Progress in a new school.

Progress in a new school.


A thieving quack.

A thieving quack.


Advertising in dentistry.

Advertising in dentistry.


A short history of local anesthesia.

A short history of local anesthesia.


The first endosseous alloplastic implant in the history of man.


Oddments in dental history.

Oddments in dental history.


In memoriam. Curt Proskauer 1887-1972.

In memoriam. Curt Proskauer 1887-1972.


Some ethnographic insights into the history of dentistry: contemporary barber-toothdrawers.


The dental society.

The dental society.


A carrier's view of dental insurance.

A carrier's view of dental insurance.


The status of the dental auxiliary in the delivery of dental health service. Auxiliary utilization.


The status of the dental auxillary in the delivery of dental health service.


The health dilemma and the delivery of dental care.


The status of the dental auxillary in the delivery of the dental health service.


The feasibility of plaque control.

The feasibility of plaque control.


Trial introduction of plaque control--CFB Chilliwack.


CFB Petawawa primary schools brush-in.

CFB Petawawa primary schools brush-in.


Four years of preventive dentistry in the Canadian Forces.


Bacterial plaque--a cause of periodontal disease.


Motivation and plaque control.

Motivation and plaque control.


Practice administration.

Practice administration.


When prevention starts young, it works.

When prevention starts young, it works.


So you're going to buy a practice.

So you're going to buy a practice.


How to pick (and train) a preventive assistant.


Design your office building to save space.


Your investments.

Your investments.


Therapy for radicular cysts.

Therapy for radicular cysts.


How aphthous ulcers respond to therapy.

How aphthous ulcers respond to therapy.


A combination technic for minor tooth movement.


Electrosurgery for a patient on anticoagulation therapy. Case report.


Forum for hygienists & assistants. The wonderful world of work.


Further, grandfathers were dentists--but his ideas aren't traditional.


Sclerosing osteogenic sarcomatosis.

Sclerosing osteogenic sarcomatosis.


"Tunnel" approach to eliminate caries at complete crown margins.


Orthodontics for the general practitioner.


How to test and hire for the professional office.


Scar scare in oral surgery--incision or aspiration.


Comprehensive care: preparing the dental student for general practice.


Is there a way to motivate your difficult patients?


A report of the mercury content of hair samples of Vermont dentists and their staffs. 1971.


The major embrasure: restorative considerations of a periodontal entity.


Bilateral mandibular subperiosteal denture implants. Case report.


Facial pain. II. Facial pain with dysfunction.


Massive osteolysis (disappearing bone, phantom bone, acute absorption of bone) of the mandible and maxilla.


Psychological aspects of dentist-patient relationships.


Pemphigus--a fresh look.

Pemphigus--a fresh look.


A philosophy of preventive thinking in crown and bridge dentistry.


How to write the minutes of that meeting.


Speech defects associated with orofacial abnormalities.


N2O-O2 analgesia system accidents and analysis.


Bingo, dental assistant.

Bingo, dental assistant.


Leadership.

Leadership.


Venipuncture--in dental therapy.

Venipuncture--in dental therapy.


To whom will expanded duties be delegated?


Needleless jet injection in comprehensive pain control and applications to oral surgery.


Acupuncture.

Acupuncture.


Case report: Dental treatment of scleroderma.


Preventive periodontics: "only a matter of time".


How (and why) patients choose a dentist--and stay with him.


Technic to help G.P. treat curved canals in posterior teeth.


Dispelling confusion about N2O analgesia.


Modern offices. "Open look" adapted to general practice.


Peer review.

Peer review.


The ecology of effective oral hygiene.

The ecology of effective oral hygiene.


Preventative dentistry. 2. Treating patients as people.


Some old and new adventures in dental research.


[The greater palatinal foramens on intra oral roentgenographs].


[Metal implants].

[Metal implants].


[How does the process of aging effect the prognosis for all dentures].


[Practical aspects of current caries research and epidemiological data].


[Surgical treatment of extreme prognathism].


Re: pollution.

Re: pollution.


Success or failure in endodontics.

Success or failure in endodontics.


Treatment of hydrocephalus. Shunts and choroid plexectomy.


Grass and ragweed pollinosis therapy. Seventeen-year study (1955 to 1971).


Clinical aspects. Minimal brain dysfunction and the hyperkinetic child.


Minimal brain dysfunction and the hyperkinetic child. Structural basis.


Normal (?) pulmonary valvular gradient..


Progressive diffuse neurologic deterioration.


Peritoneal and hemodialysis for acute glutethimide overdosage.


Iatrogenic pneumothorax.

Iatrogenic pneumothorax.


Bromide intoxication.

Bromide intoxication.


Meningoencephalitis due to Mima polymorpha.


Guillain-Barré syndrome in herpes zoster.


Ambulatory heroin detoxification in municipal hospital.


Irrelevance of relevance.

Irrelevance of relevance.


Custom modifications and specifications for bladevent implant designs to increase their biologic compatibility.


The mobile arch in the edentulous mandible. (Gum implant mobile arch).


Care and treatment of malpositioned teeth. Surgical removal of impacted canines.


Nine years' experience with "total therapy" of childhood acute lymphocytic leukemia.


An acrylate-rooted mandibular denture worn for eight years.


Rehabilitation case report.

Rehabilitation case report.


The extraction of incisors as an orthodontic measure. II.


Interpretation of radiographs.

Interpretation of radiographs.


Proposal for the design of dental chairs for treatment of the reclining patient.


The existence of Passavant's ridge.

The existence of Passavant's ridge.


Is hepatitis an unavoidable risk?

Is hepatitis an unavoidable risk?


A surgical technique for treatment of habitual luxation of the temporomandibular joint (Application in an instance of indurated temporomandibular joint luxation).


How are your public relations?

How are your public relations?


Dude dentist of Dodge.

Dude dentist of Dodge.


Malpractice problems and lawsuits.

Malpractice problems and lawsuits.


America's newest dental school.

America's newest dental school.


Consent for minors' dental care--who, when and how?


Relating, reflecting and rapping. There must be more to life than dentistry.


Probes, pockets and prevention.

Probes, pockets and prevention.


Another contraindication for odontectomy: endodontics for the wide open apex in maxillary second molars.


A porosity test for gold foil specimens.


The control of abrasion in the permanent dentition.


Help when help is needed.

Help when help is needed.


Altered states of consciousness. 3. Relevant non-drug variables.


Relationship between malalignment of the teeth and periodontal disease.


The site of mitotic activity in rat and human oral epithelium.


Rate of apposition of maxillary incisor dentin in normal male white rats.


Fractionation of parotid salivary proteins by isoelectric focusing in a wide pH range.


Copper-tin phases in dental silver amalgam alloy.


Neutron diffraction study of the  -phase in the silver-mercury system.


The 'Lyso-Plate' method for quantification of muramidase activity.


Short root anomaly.

Short root anomaly.


The prevalence of dental caries, plaque and gingivitis in 3-year-old Danish children.


Childhood leukaemia in Scotland, 1939-68.


Objective indications for respirator therapy in post-trauma and postoperative patients.


Selective in vitro cytotoxicity of a glycolytic enzyme inhibitor for immature lymphoid cells.


Glycolytic and respiratory enzyme activity in relation to leucocyte maturation.


Symposium on complications of middle third fractures.


Involvement of soft tissue by odontogenic keratocysts (primordial cysts).


Metastasis of carcinoma of the lung by implantation in tooth sockets.


Central giant-cell granuloma. Several interesting cases.


Penicillin--the duration of its activity in blood clots.


Glossopharyngeal neuralgia. Its diagnosis and treatment.


Involvement of the mandible in Gaucher's disease. Report of a case with post-mortem findings.


An adjustable locking plate for sectional metal cap splints. A further report.


Cyclization of chloroplast DNA fragments of Chlamydomonas reinhardi.


Effect of streptomycin on ribosome interconversion, a possible basis for the action of the antibiotic.


Genetic heterogeneity of xeroderma pigmentosum demonstrated by somatic cell hybridization.


Induction of  -globin synthesis in the  -thalassaemia of Ferrara.


Conformational requirements of acetylcholine analogues and local anaesthetics.


Acetylcholine formation in mouse brain and effect of cholinergic drugs.


-Aminobutyric acid uptake by sympathetic ganglia.


Inhibition of the extraneuronal uptake of catecholamine in the isolated rat heart by cholesterol.


Dose-rate and mutation frequency after irradiation of mouse spermatogonia.


Directional information transfer in protein helices.


Effects of anti-inflammatory drugs on prostaglandin biosynthesis.


Presence of poly (A) in the polyribosome-associated RNA of Sindbis-infected BHK cells.


Effect of colchicine and vinblastine on the agglutination of polymorpho-nuclear leucocytes by concanavalin A.


Anti-theta serum-induced supression of the cellular transfer of tumour-specific immunity to a syngeneic plasma cell tumour.


Significance of intracortical inhibition in the visual cortex.


Pseudoneutropenia in Negroes: a normal phenomenon.


Recognition of coronary artery disease.

Recognition of coronary artery disease.


Depression.

Depression.


Legal aspects of exercise testing.

Legal aspects of exercise testing.


Drugs versus pyschotherapy.

Drugs versus pyschotherapy.


Hypersensitivity pneumonitis due to organic dust inhalation.


Segmental polycystic disease.

Segmental polycystic disease.


Developmental factors in functional sexual disorders.


Foramen magnum lesion.

Foramen magnum lesion.


Intracerebral hemorrhage during hemodialysis.


Clinical meningeal leukemia in acute myelocytic leukemia.


Protein-losing enteropathy caused by intestinal lymphangectasia.


College drug scene as it is.

College drug scene as it is.


Blood transfusion: recent medical-legal developments.


Trauma as national problem.

Trauma as national problem.


Relation between combined widths of incisors and dimensions of the dental arches.


Duration of swallowing with and without anesthesia of the temporomandibular joints.


Periodontal healing following experimental injury to root surfaces of human teeth.


A further testing of the effect of dental materials on growth and adhesion of animal cells in vitro.


Transmission electron microscopy on sound demineralized guinea pig dentin.


Ultrastructure of palatal epithelium in guinea pigs 5 minutes and 6 hours after excisional wounding.


Scanning electron microscopic studies on demineralized guinea pig dentin.


The effect of roentgen irradiation on the formation of enamel and dentin in maxillary rat incisors.


Treatment of hypersensitive root surfaces by calcium hydroxide.


Studies on tongue carcinogenesis in rats using DMBA with and without cyanoacrylate adhesive.


Patterns of change in human mandibular arch width during jaw excursions.


Myoneural maturation and function of the foetal rat tongue at the time of secondary palate closure.


A study of the enzyme patterns of some oral filamentous bacteria by starch gel electrophoresis.


Electrophysiological evidence on the types of nerve fibres excited by electrical stimulation of teeth with a pulp tester.


Ontogeny of tooth replacement in the guinea pig (Cavia cobya).


Eruption of teeth among the racial groups of eastern New Guinea: a correlation of tooth eruption with calendar age.


Localization of alkaline phosphatases in human cap-stage enamel organs by electron histochemistry.


A high-sucrose medium for the identification of Streptococcus mutans.


The dental art of ancient Mexico.

The dental art of ancient Mexico.


Factors in pathogenesis of central-nervous-system leukaemia. Eighty-three (50%) of 165 children with acute lymphoblastic or acute stem-cell leukaemia presenting during 1958-70 developed leukaemia of the central nervous system (C.N.S.). The rate of incidence of this complication is fairly constant throughout the first two-and-a-half years of the disease, but falls thereafter. The incidence of C.N.S. leukaemia is inversely correlated with the platelet count at the time of initial diagnosis of leukaemia, and directly correlated with the total leucocyte count and the presence of lymph-node enlargement. The major effect of initial leucocyte count is on the time of onset of clinical symptoms. It is suggested that leukaemic cells usually enter the C.N.S. from the blood as a result of intracranial petechial haemorrhage occurring around the time of initial diagnosis of leukaemia, and that the time for subsequent development of symptoms of C.N.S. disease is largely determined by the number and replication rate of leukaemic cells which gain access to the C.N.S. at that time. The increasing frequency of diagnosis of C.N.S. leukaemia in recent years is not wholly explained by increasing survival, and may in part be related to changes in the pattern of antileukaemic therapy.Prophylaxis for C.N.S. leukaemia should be instituted as early as practicable after diagnosis; the identification of a high-risk group may permit this to be done selectively.


Pit and fissure sealants. A new concept in preventive dentistry.


Conducting a practice for prevention of oral disease.


Moulding techniques and machines. 3. Variables of moulding.


Gypsum in context. 2.

Gypsum in context. 2.


Arthritis as the presenting feature of childhood leukemia.


He helps ease the world's toothache.

He helps ease the world's toothache.


Cohesive golds a review of the literature.


Coronal fractures involving periodontal tissues--a case report.


Dental health education of the grade 1 child.


The gothic arch tracing and facial dimensions in the edentulous patient.


Certification and licensing in the allied health professions.


Evaluating dental student performance with time-lapse photography.


Profiles of dentists trained in schools of public health.


Comprehensive approach to evaluation of clinical performance.


Applying dental techniques to fabrication of embryology teaching models.


Application of skill performance curves to clinical evaluation of dental students.


Clinician's view of future dental practitioners.


Making large featherweight tooth models.


Teaching community dental hygiene.

Teaching community dental hygiene.


SASHEP. 1. Issues and problems of accreditation.


Lactic acid dehydrogenase isoenzyme in periodically amputated rat incisor pulp.


Experimental study on the antibacterial effects of root canal filling materials.


Experimental study on antibacterial effect of dexamethasone-containing antibiotics.


Radiographic study on the resorption of iodoform paste in the apical lesion.


Hematology of dental pulp in vital pulpotomy.


The management of a periodontal patient.


Root treatment without apical curettage. Case report.


Applied radiographs.

Applied radiographs.


Dentistry for the pregnant patient.

Dentistry for the pregnant patient.


The health questionnaire in general dental practice. 9. Steroids and dentistry.


What group practice means to the dentist and to the patient.


Getting it together in order to deliver to people.


Condominium: as an apartment, O.K., as an office, better yet.


Law and economics of dental practice. Financial questions and answers.


Dental health inservice training in nursing homes.


American Indians in the health professions.


Oral physiotherapy.

Oral physiotherapy.


Caries prophylaxis via local enamel hardening.


Oral rehabilitation with the use of inlay series.


The ring restoration. (A new method for preparing cavities for the Addent XV composite material).


Preparation of a crown in the presence of an existing metal denture.


A new aid for demonstration of the pocket floor in periodontal radiography.


[The extraction of incisors as an orthodontic measure. 3].


[Unusual complication during extraction].


Chronically recurrent aphthae: dentistry and electroacupuncture.


Tissue response to varying surface finishes of titanium implants.


Bruxism.

Bruxism.


Forensic dentistry.

Forensic dentistry.


If you got 'em floss 'em. Preventive statistics after twelve years.


Letters to the editor: pseudo-sracomatous fascilities.


Hepatic glycogen synthetase deficiency. Further studies on a family.


Serum immunoglobulin levels in children with acute lymphoblastic leukaemia and their mothers and sibs.


The distribution of hydroxyproline in the dentine of carious human teeth.


Some factors affecting the metabolism of fructan by human oral flora.


Electron microscopic localization of alkaline phosphatase in the enamel organ of the young rat.


Microstructural and microradiographic qualities of lemon shark enameloid.


Pressure differential favouring tooth eruption in the dog.


Tooth contacts on the functional and nonfunctional side in children and young adults.


A semiquantitative microradiographic study of the distribution of organic mass in human carious dentine.


A method for sampling and analysing thin layers of enamel for carbonate, fluoride and other inorganic components.


Maxillary dental arch width in Chinese living in Liverpool.


The effect of cortisone treatment on the weight and nitrogen content of the salivary glands in the rat.


The response of the masseter and temporal muscles following electrical stimulation of oral mucous membrane in man.


The in-vitro effect of fungal dextranase on human dental plaque.


Processes of mammalian tooth development as illustrated by dental ontogeny in the mole Scapanus latimanus (Talpidae: insectivora).


A quantitative morphological study of the effect of urethane on the stimulation of salivary gland growth by isoproterenol in the rat.


The sinus node in chronic granulocytic leukemia.


The phosphorescence of the cut surfaces of organs important in oral physiology.


Innovative prosthetics for a cleft palate patient.


Instructions for patients who are to receive analgesia or general anesthesia.


Back the PAC.

Back the PAC.


Assessment of the mixed leucocyte reaction by target cell death: a study of leukaemic cells.


Tomorrow's dentists--a different blend.

Tomorrow's dentists--a different blend.


Opoortunities for political action--1972.


Physical fitness for the prevention of coronary attacks.


Smoking characteristics of patients with oral carcinoma and the risk for second oral primary carcinoma.


Moving teeth with high frequency oscillations; theory, method, instrumentation, and initial tests.


New England Dental Reports: continuing dental education on open-circuit television.


A psychiatric appraisal of tongue symptoms.


Dentigerous cyst of the nasal cavity and maxillary sinus: report of case.


Status report on cement bases, cavity liners, varnishes, primers, and cleansers. Council on Dental Materials and Devices. Council on Dental Therapeutics.


Survey of the dental laboratory industry, 1971. II. Dental laboratory personnel. Bureau of Economic Research and Statistics.


1971 survey of dental practice. IX. Dentist busyness. Bureau of Economic Research and Statistics.


1971 survey of dental practice. X. Some characteristics of dental practice according to level of gross receipts. Bureau of Economic Research and Statistics.


Course listing for September 1972 through January 1973.


Evaluation of a new non-extraction technique for serum thyroxine measurement.


Anaerobic bacteria from the advanced periodontal lesion.


The relationship of endodontic-periodontic lesions.


Relationships between endodontics and periodontics.


Preventive periodontics utilizing an oral physiotherapy center.


A comparison of selected oral hygiene devices in dental plaque removal.


Evaluation of an oral physiotherapy center in the reduction of bacterial plaque and periodontal disease.


Alveolar bone response to the electrosurgical scalpel.


The effect of increased blood oxygen tensions on induced periodontal disease.


Summary of patient interpretation after experiencing periodontal therapy.


Periodontosis: a periodontal syndrome.

Periodontosis: a periodontal syndrome.


Leukemic xanthomatosis with a missing no. 9 chromosome.


On fibrinolysis. A. In pregnancy, labour, puerperium and during treatment with sex hormones. B. In human ontogenesis and in human organ culture.


Analysis of mental state in workers operating port mechanical equipment.


Chronic diseases among seamen and fishermen.


Differential diagnosis of psychiatric disturbance in pre-school children.


The index of information level of the internal speech as a method of assessment of hearing rehabilitation in industrial workers.


Problem of clinical and electroencephalographical correlation in the course of hyperthyroidism.


The biological significance of sea-water distillate used as drinking water on ships.


Characteristics of mechanical vibration on harbour tugboats.


Investigations on exposure of ship painters to organic solvents.


Hygienic estimation of the ventilation in ship engine rooms.


Environmental factors causing neurosis in seamen.


Focus of tularemia in the Pisz district.


Changes in survival in haematological malignancies.


The hydrodynamics of the dentine; its possible relationship to dentinal pain.


Variations in the mineral content of the enamel of Polynesian teeth.


Clinical experience of auto- and allotransplantation of teeth.


The current status of autogenous transplantation as applied to the maxillary canine.


The nitroblue tetrazolium dye test.

The nitroblue tetrazolium dye test.


The current status of coronary arteriography.


Autotransplantation of teeth with use of cell cultivation technique.


Mitral annulus calcification in Marfan's syndrome: report of a case.


HMO's and other delivery systems.

HMO's and other delivery systems.


Prophylactic considerations in patients with prosthetic heart valves undergoing dental procedures.


Potential legal difficulties with voluntary sterilization.


Forest Haven: stepping-stone to citizenship.


Local academic training in public health.


Acute leukaemia with mastocytosis.

Acute leukaemia with mastocytosis.


Complications of vertebral angiography.

Complications of vertebral angiography.


Proventriculus of a marine annelid: muscle preparation with the longest recorded sarcomere. EACH MUSCLE OF THE SYLLID (ANNELIDA: Polychaeta) proventriculus, the region of the gut posterior to the pharynx, contains a single zigzagging Z band, flanked on each side by a sequence of I-A-H-A-I bands defined by thick (60-90 nm) and thin (5 nm) filaments. The thick filaments show a 14-nm periodicity similar to paramyosin. The muscle cell terminates at the level of the outer I bands. The muscle does not include a complete sarcomere in the strict sense, as defined by a pair of Z bands, but the equivalent H-H distance reaches about 40 mum. Electrophysiological evidence suggests that contraction and relaxation of the cell are, respectively, associated with depolarizing and hyperpolarizing potentials.


Excretion of deoxyribonucleic acid by lymphocytes stimulated with phytohemagglutinin or antigen. When human lymphocytes are cultured in the presence of phytomitogens, 70-90% of the cells undergo blast transformation and synthesize DNA. However, less than 40% of these lymphocytes actually undergo mitosis while 35-90% of the newly synthesized DNA is excreted into the media. The release of DNA by the cells is selective since experiments with [(14)C]uridine indicate that RNA is not lost into the culture media. DNA excretion occurs under many culture conditions. The excreted DNA has an estimated molecular weight of 3 to 12 x 10(6) as determined by gel filtration on Sepharose 2B. It forms a single sharp peak at a density of 1.055 g/cm(3) when examined by sucrose density gradient centrifugation, suggesting that the DNA is complexed to protein or lipid.


Functional nonequivalence of   and   hemes in human adult hemoglobin. Nuclear magnetic resonance studies of the contact-shifted spectra of heme protons in deoxyhemoglobin A from human adults show conclusively that oxygen binds to the alpha hemes in preference to the beta hemes. The preferential binding is produced in 10% hemoglobin solution at neutral pH by either a 15-fold molar excess of 2,3-diphosphoglycerate or a 5-fold molar excess of inositol hexaphosphate. Preferential binding is not observable in the absence of the organic phosphates. The results indicate that the oxygenation of hemoglobin may be described by a sequential model, or by a concerted model that allows the alpha hemes to bind ligand first.


Is prolactin mitogenic for mammary epithelium? Prolactin administration to mature virgin mice leads to prolilferation of epithelium of the mammary gland. In organ culture, prolactin is not mitogenic, but insulin and insulin-free serum are. These observations are reconciled by the finding that insensitive epithelium is sensitized to insulin and/or serum by prolactin treatment in vivo. Thus, it appears that prolactin acts indirectly as a mitogen by rendering the cells susceptible to the aforementioned mitogens.


On the theory of ion transport across the nerve membrane. VI. Free energy and activation free energies of conformational change. Empirical functions, such as n(infinity)(V) and tau(n)(V) (of the Hodgkin-Huxley type), can be recast in terms of more fundamental functions F(V) (related to a conformational free energy change) and theta(V) (related to the corresponding free energies of activation). Examples of F(V) and theta(V) are given, for squid and frog node. F(V) is essentially a quadratic function of V. The possible molecular origin, for protein-like subunits, of the linear (e.g., net charge) and quadratic (e.g., polarizability) terms in F(V) is discussed. The F(V), theta(V) kind of analysis leads rather automatically to a simple explanation of the well-known approximate coincidence in location (V value) of the maximum in tau(n)(V) (time constant) and the steeply rising part of n(infinity)(V) (also m, 1 - h).


[On the role of RNA in gene amplification]. A complex of ribosomal DNA with RNA has been isolated from ovaries of metamorphosing tadpoles of Xenopus laevis. The complex is disrupted by treatments that destroy hydrogen bonds, and the sedimentation of the DNA within the complex is sensitive to RNase. We suggest that the RNA-ribosomal DNA complex is an intermediate in the synthesis of amplified ribosomal DNA and that the RNA is a template. In addition, in a preliminary attempt to mimic the amplification process in vitro, we have demonstrated the use of this RNA from the complex as a template for DNA synthesis by a DNA polymerase isolated from ovaries of Xenopus.


An RNA-DNA complex intermediate in ribosomal gene amplification. An RNA-ribosomal DNA complex can be isolated from ovaries of Xenopus laevis incubated in vitro during the amplification stage. A part of the RNA present in the complex is resistent to RNase but becomes completely sensitive after heat denaturation, a treatment that also allows the separation of the RNA from the DNA. The size of the RNA-ribosomal DNA complex is strongly reduced after treatment with RNase. A small fraction of the RNA present in the complex is complementary to the spacer region of the strand, which is not transcribed in vivo into cytoplasmic 18S and 28S ribosomal RNA.


Diphenylhydantoin inhibition of sodium conductance in squid giant axon. Diphenylhydantoin, in concentration of 5-50 muM, decreases the early, transient (sodium) currents of voltage-clamped squid giant axons. These effects are dose-dependent and largely reversible. It appears that diphenylhydantoin reduces the number of open, early, transient (sodium) channels.


Radioimmunoassay of mammalian type-C viral proteins: interspecies antigenic reactivities of the major internal polypeptide. Mammalian type-C viruses contain a major internal polypeptide of about 30,000 daltons that is characterized by both intraspecies and interspecies antigenic reactivities. Radioimmunoprecipitation assays were used for measurement of this protein; the assay was based upon interspecies reactivities of the protein. As little as 5 ng of the group-specific antigen of murine leukemia virus can be measured by radioimmunoprecipitation assays, thus providing an approximate 10,000-fold increase in sensitivity over the standard immunodiffusion procedure. The type-C viruses that were recently isolated from a woolly monkey and gibbon ape each have an interspecies type-C antigenic reactivity. The primate viruses, however, could be distinguished from the type-C viruses of murine, rat, hamster, and feline origin that were more highly related to each other. The interspecies reactivity of the 30,000-dalton polypeptide is an immunological marker of the mammalian type-C viruses, since even with this sensitive assay other mammalian viruses with RNA-dependent DNA polymerase activity did not contain the type-C interspecies antigen.


Solid-phase conjugation of ferritin to Fab-fragments of immunoglobulin G for use in antigen localization on thin sections. A technique for the solid-phase conjugation of ferritin to monovalent antibodies (Fab-fragments of immunoglobulin G) is described in which Fab-fragments from sheep antiserum to rabbit Fab-fragments are first adsorbed to Sepharose containing insolubilized rabbit immunoglobulin G, and subsequently allowed to couple with ferritin previously activated with toluene-2,4-diisocyanate. The conjugate, after elution from the adsorbent, is separated from free ferritin and unconjugated Fab by gel chromatography. We have used this conjugate as a common second-step reagent for the surface localization of intracellular antigens on thin sections of tissue embedded in albumin. The first-step reagent consists of specific rabbit antibodies (IgG) directed against the tissue component under study. An example of the use of this technique for the localization of trypsinogen in bovine exocrine pancreatic cells is given.


Characterization and partial purification of the acetylcholine receptor from Torpedo electroplax. Binding of acetylcholine in the concentration range 1 nM-1 muM was measured by equilibrium dialysis to a particulate preparation of Torpedo electroplax, without or with prior treatment of the tissue with one of three chemical modifying reagents. Significant reduction in binding of acetylcholine resulted after treatment with 1,4-dithiothreitol, p-chloromercuribenzoate, or p-(trimethylammonium)-benzenediazonium fluoroborate. Partial reversal of the reduction in binding occurred when dialysis was performed in the presence of 5,5'-dithiobis-(2-nitrobenzoic acid) or potassium ferricyanide (in the case of treatment with dithiothreitol), and 2-mercaptoethanol (in the case of treatment with p-chloromercuribenzoate). It is concluded that the functional acetylcholine-receptor macromolecule of Torpedo electroplax has disulfide bond(s), sulfhydryl group(s), and one or more of the amino acids vulnerable to diazotization by p-(trimethylammonium)-benzenediazonium fluoroborate. This, plus the effect of phospholipase C (EC 3.1.4.3) in elimination of detectable binding of acetylcholine after electrofocusing, is additional evidence that the functional acetylcholine receptor is a phospholipoprotein or a phospholipid-protein complex, which has a low isoelectric point of 4.5 +/- 0.2, yet is denatured by exposure to low pH for 24 hr. Due to this adverse effect, recovery of binding of acetylcholine after electrofocusing, as detected by equilibrium dialysis or ultrafiltration, is only 23% and, so far, only 6.3-fold purification of functional acetylcholine receptors by this technique is possible. Three or two forms of acetylcholinesterase (EC 3.1.1.7), whose peaks have isoelectric points ranging from 4.3 to 7.2, appear after electrofocusing of Torpedo extracted with 1% Triton X-100 or Lubrol, respectively. The major peak in either preparation has an isoelectric point of 5. Although the peaks of the functional acetylcholine receptors and of acetylcholinesterase of Torpedo electroplax are separable by electrofocusing, it has not been possible to isolate fractions that contain functional receptors but that are free of acetylcholinesterase. The opposite is possible.


DNA polymerase of chicken embryo: purification and properties. The almost complete purification of the previously reported DNA polymerase of chicken embryo is described; in the final isolation step the enrichment of the enzyme, which comprises about 0.01% of the protein extractable from 10-day-old embryos, is more than 9000-fold. The enzyme is a basic protein (pI = 9.15), of molecular weight about 27,000. It exhibits no nuclease activity, requires Mn(2+) ion for activity, and may contain Zn. It is very sensitive to oxidation.


Purification and biological activity of thymosin, a hormone of the thymus gland. The purification and chemical properties of thymosin, obtained from bovine thymus tissue, are described. The biological activity of the thymic hormone has been assessed by a newly developed rosette assay, which permits measurement of thymus-dependent lymphoid cells. Thymosin activity is associated with a physico-chemically homogeneous protein of molecular weight 12,600. The hormonal activity is evident in in vitro incubation assay, after injection into adult thymectomized mice, and in prolonging survival of neonatally thymectomized mice and the reconstitution of their response to a skin allograft.


Properties of the refolding and unfolding reactions of ribonuclease A. Both the refolding kinetics and unfolding kinetics of ribonuclease A have been measured at the same final conditions, as a function of temperature at pH 3.9, by stopped-flow (pH-jump) experiments; absorbance changes at 240 and 286.5 nm were measured. Refolding follows first-order kinetics in the upper two-thirds of the thermal transition zone. Under the same conditions, the unfolding kinetics are biphasic; the terminal phase has the same rate constant as refolding. The biphasic kinetics of unfolding demonstrate the presence of intermediate states. Since both the refolding and unfolding kinetics are consistent with a simple sequential model, the intermediates satisfy kinetic criteria for being on the direct pathway of unfolding. At temperatures just above the transition zone, the fast phase of unfolding becomes the major kinetic phase. The rate of the slow unfolding reaction increases rapidly with temperature, and approaches the average rate of the fast phase at temperatures just above the transition zone. The entire set of kinetic results can be reproduced semiquantitatively by assignment of values to four parameters in a cooperative sequential model. However, reasons are given for the belief that this simple model will have to be generalized before it can give a realistic description of the kinetics of the unfolding reaction.


Deamidation in vivo of an asparagine residue of rabbit muscle aldolase. Microheterogeneity of rabbit muscle aldolase is caused by deamidation in vivo of an asparagine residue near the C-terminus of each subunit. Isotopic labeling of a peptide containing the asparagine residue at various time intervals before isolation of aldolase permits estimation of the half-time for the deamidation as about 8 days, which is about the time estimated for the half-life of the enzyme in vivo. It is concluded that the aldolase as genetically determined is a tetramer, designated alpha(4), that undergoes random deamidation to form alpha(3)beta, alpha(2)beta(2), and alphabeta(3) species as intermediates in the formation of beta(4), the species in which all of the specific asparagine has been deamidated. Isoelectric focusing data indicate that the subunits do not exchange appreciably in vivo.


Conformational interconversions of the cyclic hexapeptide cyclo(Pro-Gly) 3 . A cyclic hexapeptide, cyclo(Pro-Gly-Pro-Gly-Pro-Gly), has been synthesized; its solution conformations were examined by 220-MHz nuclear magnetic resonance spectroscopy. The solution structures have been deduced, and shown to vary as a function of solvent polarity. In addition, it has been found that this cyclic peptide binds alkali metal cations. While the predominant conformation of this cyclic peptide is 3-fold symmetric in the apolar solvent methylene chloride, an asymmetric structure is preferred in some polar solvents (water, dimethylsulfoxide). However, addition of alkali metal salts, such as sodium thiocyanate, to dimethylsulfoxide solutions of the peptide shifts the conformational equilibrium in favor of a second type of C(3)-symmetric structure, presumably the result of the formation of a stable peptide-metal ion complex. Nuclear magnetic resonance data suggest that the peptide in methylene chloride solution takes up a conformation containing three cis' Pro C(alpha)-C=O bonds and three cis Gly-Pro peptide bonds; that water and dimethylsulfoxide stabilize a conformer in which one (or two) sets of such bonds of a given Pro-Gly unit have undergone interconversion to trans'/trans forms; and that alkali metal cations complex the cyclic peptide in a C(3)-symmetric all-trans'/trans structure.


Physicochemical characterization of mitochondrial DNA from pea leaves. The mitochondrial DNA from pea leaves exists in a circular conformation. 25% of the circular molecules exist as supercoils, and 10% of the molecules are dimers. The molecular weight of mitochondrial DNA is about 66 to 70 x 10(6) by electron microscopy, and 74 x 10(6) from its renaturation kinetics. No evidence for inter- and intramolecular heterogeneity is found.


Surface properties of membrane systems: apoprotein of the Folch-Lees proteolipid from beef-brain myelin. Structural proteins in biological membranes are bimodal and ideally possess a unique surface activity that should be amenable to study by monolayer techniques. Proteins so studied, however, display, of necessity, a surface activity that reflects the laboratory history of the protein. The Folch-Lees proteolipid apoprotein was isolated from calf-brain myelin in both an organic solvent (CHCl(3)-CH(3)OH-CH(3)COOH; 50:50:1) and water. The apoprotein did not spread as a film from water, but did spread readily from the organic solvent into films that had high saturation pressures. The partitioning of the apoprotein from organic solvent to water was found to be reversible, as was the gain and loss of surface activity. Infrared spectroscopy demonstrated that the preponderant structure in films of the apoprotein was not that of extended polypeptide chains. The results suggested that the preferred structures at the interface are bimodal coils of alpha helix. This structure can sustain the high film pressures observed, whereas beta keratin structures would build films with high surface viscosity and very low surface pressure.


Coupling of a new, active morphine derivative to sepharose for affinity chromatography. A new, pharmacologically active morphine derivative, 6-succinylmorphine, was synthesized. The properties of this compound and evidence for its structure are presented. Succinylmorphine was covalently coupled to ethylamino-Sepharose. Morphine-Sepharose containing up to 40 mug of morphine did not block the electrically stimulated contraction of isolated guinea pig ileum, but after alkaline hydrolysis of beads containing 2 mug of morphine the supernatant completely blocked contraction. This block was reversed by the specific morphine antagonist naloxone. Antibodies to morphine were removed from serum by morphine-Sepharose, but not by ethylamino-Sepharose, providing evidence of the efficacy of the beads for affinity chromatography.


Increased susceptibility of cells treated with interferon to the toxicity of polyriboinosinic-polyribocytidylic acid. Concentrations of the synthetic polymer polyriboinosinic.polyribocytidylic acid that produced no detectable toxicity in normal L cells produced marked cytotoxicity in L cells treated with interferon. This increase in the susceptibility of cells to the toxicity of the polymer was also observed in human cells and secondary mouse embryo cells treated with homologous interferons before exposure to the polynucleotides. The degree of enhancement of toxicity was dependent on the concentration of interferon to which the cells were exposed. The ratio of antiviral activity induced by interferon to enhancement of toxicity by interferon remained constant through about 1000-fold purification. Various interferon preparations induced by viruses or by polyriboinosinic.polyribocytidylic acid in vivo or in vitro, and international reference standard interferons all exhibited enhancement of toxicity. Both enhancement of toxicity and antiviral activity were destroyed by trypsin and by incubation at 56 degrees for 1 hr, did not act on heterologous cells, were not sedimented by ultracentrifugation, and were not inactivated by ribonuclease, deoxyribonuclease, irradiation with ultraviolet light, or exposure to a pH of 2.


5-Fluoro-2'-deoxyuridylate: covalent complex with thymidylate synthetase. 5-Fluoro-2'-deoxyuridylate causes a rapid inactivation of thymidylate synthetase that is dependent upon prior complexation of the cofactor 5,10-methylenetetrahydrofolate. The enzyme-5-fluoro-2'-deoxyuridylate complex may be isolated on nitrocellulose membranes and is not disrupted by 6 M urea. Upon reaction of 5-fluoro-2'-deoxyuridylate with the enzyme in the presence of 5,10-methylenetetrahydrofolate a rapid loss of absorbance is observed at 269 nm, the absorption maximum for the pyrimidine chromophore. It is concluded that a covalent bond is formed between the 6-position of 5-fluoro-2'-deoxyuridylate and a nucleophilic group of the enzyme that is involved in catalysis.


Dopamine- -hydroxylase activity in mouse neuroblastoma tumors and in cell cultures. Dopamine-beta-hydroxylase activity is present in mouse neuroblastoma C-1300 tumors. The activity is proportional to the weight of the tumor. Serum activity is markedly increased in mice that bear the tumors. Treatment of mice with 5-bromodeoxyuridine causes marked inhibition of tumor growth and decrease of dopamine-beta-hydroxylase activity in the serum. The histochemical studies reveal that 1-5% of the cells in mouse C-1300 neuroblastoma tumors contain catecholamines and that catecholamine-containing processes terminate mainly around blood vessels of the tumor. Dopamine-beta-hydroxylase is present in clonal neuroblastoma cell lines. The cell line with the greater tendency to form axon-like processes has a higher activity of this enzyme.


Observation of cooperative ionizations in hemoglobin. (19)F-Nuclear magnetic resonance studies of specifically fluorinated hemoglobin derivatives have been used to determine the apparent pK(a) of the histidine beta146 imidazole in deoxyhemoglobin. The titration of this residue was found to be abnormally sharp, particularly in the presence of diphosphoglyceric acid. The explanation advanced for this unusual titration curve may have implications for the mechanism of cooperative ligand binding. The possible role of such ionizations is discussed in light of some chemical evidence that the cooperative binding process is governed to a greater extent by internal nonpolar forces than by electrostatic interactions of exposed groups.


Ultraviolet chromophore transitions in the rhodopsin spectrum. Difference spectra measured at -105 degrees show two decreases in the ultraviolet absorption spectrum of rhodopsin upon bleaching that cannot be attributed to changes in protein conformation. These absorbancy decreases in rhodopsin are consistent with a cis-trans isomerization of the chromophore.


Association of actinomycin D and deoxyribodinucleotides as a model for binding of the drug to DNA. The association of actinomycin D and eleven different deoxyribodinucleotides were studied as model complexes for the interaction of actinomycin D and DNA. All of the deoxyribodinucleotides containing guanine will complex with actinomycin D, and the guanine base has a preferred orientation with respect to the chromophore of actinomycin D. The spectrophotometric binding curve for pdG-dC is sigmoidal (Hill constant = 2.0 +/- 0.2), while the binding curves of all other dinucleotides of the form pdN-dG are hyperbolic. The equilibrium expression for the complex with pdG-dC was second order in dinucleotide concentration, with K(App) = 1.7 x 10(7) liter(2)/mol(2), while the binding of pdC-dG was first order in dinucleotide concentration, with K(App) 1.8 x 10(3) liter/mol. The sigmoidal pdG-dC binding curve shows that actinomycin D has a preference for G-C sequences of DNA as potential binding sites.


Relaxation study of complex formation between monovalent cations and cyclic polyethers. Equilibrium quotients for the 1:1 complexes of dibenzo-30-crown-10 with Na(+), K(+), Rb(+), Cs(+), NH(4) (+), and T1(+) in methanol solution have been determined spectrophotometrically. The observed selectivity pattern is discussed in terms of the hydration energy of the cations and the cation-ligand binding energy. The rate of complex formation is diffusion-controlled. Relaxation amplitude data are consistent with a mechanism that involves conformational change of the crown compound.


Conformation of lysine vasopressin: a comparison with oxytocin. Starting with assignments of proton nuclear magnetic resonance previously made for oxytocin in deuterated dimethylsulfoxide at 220 MHz, we have assigned resonances for the mammalian antidiuretic hormone, lysine vasopressin. The results demonstrate that spectral assignments of neurohypophyseal hormones and their congeners can, within certain limits, be derived from each other. Comparison of the spectra of lysine vasopressin and oxytocin suggests that the gross backbone conformations of their 20-membered ring components are for the most part similar in deuterated dimethylsulfoxide, whereas the C-terminal acyclic amino-acid sequence of lysine vasopressin is more flexible than that of oxytocin.


Electron microscope studies of heteroduplex DNA from a deletion mutant of bacteriophage phiX-174. A population of double-stranded replicative form of DNA molecules from bacteriophage varphiX-174 carrying a deletion of about 9% of the wild-type DNA has been discovered in a sample cultivated under conditions where the phage lysozyme gene is nonessential. The structures of deleted monomers, dimers, and trimers were studied by the electron microscope heteroduplex method. The dimers and trimers are head-to-tail repeats of the deleted monomers. Some interesting examples of the dynamical phenomenon of branch migration in vitro have been observed in heteroduplexes of deleted dimer and trimer strands with undeleted monomer viral strands from the wild-type phage.


Calcium-like action of phenethylbiguanide and related compounds: inhibition of pyruvate kinase. Pyruvate kinase (EC 2.7.1.40) is inhibited by phenethylbiguanide. The kinetics of inhibition are competitive between biguanide and divalent, but not monovalent, metal cation activators of the enzyme; biguanide inhibition thus resembles inhibition by Ca(++). Alteration of either the polar or nonpolar portion of the phenethylbiguanide molecule quantitatively reduces its effectiveness as an inhibitor of pyruvate kinase, but the kinetics of inhibition remain qualitatively unchanged. Measurements of [(3)H]phenethylbiguanide binding to the enzyme indicate the presence of a single class of about 12 binding sites per enzyme molecule; binding characteristics are not significantly different in the presence of either monovalent or divalent metal cations. Studies with (45)Ca(++) and (54)Mn(++) demonstrate about 4 metal binding sites per enzyme molecule; phenethylbiguanide displaces these metal cations from the enzyme. Studies with several enzymes, dependent upon divalent metal cations, of both metal-bridge and substrate-bridge classes fail to show significant inhibition except at much higher phenethylbiguanide concentrations.


Purification and properties of biologically active messenger RNA for a myeloma light chain. A cell-free system derived from Krebs II ascites tumor has been used to assay biologically active mRNA for myeloma (MOPC-41) light chain during its purification by oligothymidylate-cellulose chromatography and sucrose gradient centrifugation. The purified mRNA directs the synthesis of a product that yields tryptic peptides corresponding to those derived from authentic myeloma protein and that forms a specific immunoprecipitate with antibody directed against the MOPC-41 protein. The fact that the light-chain mRNA anneals to oligothymidylic acid-cellulose suggests that it, like several other eukaryotic mRNAs, contains a region rich in adenylic acid residues. The most active fractions of light-chain mRNA, representing about 0.1% of the RNA originally extracted from membrane-bound myeloma polysomes, sediment as a discrete peak with an s(20,w) of about 13, roughly corresponding to an RNA molecule containing 850 bases. The results suggest that the light-chain mRNA is monocistronic and that it contains about 200 more bases than would be necessary to encode the variable and constant regions of a single light-chain molecule.


A novel mechanism for the NIH-shift.

A novel mechanism for the NIH-shift. Kinetics of aromatization of 1,4-dimethylbenzene oxide (I) to 2,5-dimethylphenol (II) and 2,4-dimethylphenol (III), the latter arising by an NIH-Shift of a methyl group, as measured in the pH range 1-12, follow the equation -d[I]/dt = [I][k(0) + (k[unk] + k[unk])aH], where k(0) = 4.8 x 10(-3) sec(-1), k[unk] = 7.3 x 10(2) M(-1) sec(-1), and k[unk] = 5.3 x 10(2) M(-1) sec(-1). The ratio of products II to III at pH >/= 6 in the spontaneous rearrangement (k(0)) is 13 to 87, and changes to 54 to 46 in the acid-catalyzed rearrangement (k[unk] and k[unk]). While no intermediate is detectable in the acid-catalyzed rearrangement of the arene oxide by pathway k[unk], simultaneous addition of water (and other nucleophiles) by pathway k[unk] leads, via the intermediate 1,4-dimethyl-2,5-cyclohexadiene-1,4-diol (IV), to the phenols II and III. This new mechanism for the NIH-Shift serves as a model for the ease of nucleophilic addition to other arene oxides, such as those of the polycyclic aromatic hydrocarbons recently implicated in mechanisms of carcinogenesis.


Protein changes in different brain areas as a function of intermittent training. Incorporation of [(3)H]leucine into protein of eight different brain areas in rats was determined during 1 month of intermittent training for reversal of handedness. The incorporation values of all areas of the trained animals were lower than those of the controls. This finding was corroborated by autoradiography. After initial training the relative specific activities of the sensory-motor and entorhinal cortex and reticular formation were low compared to those of the hippocampus. With more training and time, these values became inversed.


Synthesis, acetylation, and phosphorylation of histone IV and its binding to DNA during spermatogenesis in trout. During spermatogenesis in trout testis, histone IV is extensively modified by acetylation and phosphorylation. To examine the relationship of synthesis of histone IV to its modification, histone IV labeled with [(3)H]aminoacids and inorganic [(32)P]phosphate was prepared from testis cells by acid extraction and column chromatography. Purified histone IV was resolved by starch gel electrophoresis into 10 bands, of which nine are modified by acetylation and/or phosphorylation. In the first 4 hr of labeling, the diacetyl-histone IV band showed the highest proportion of [(3)H]aminoacid label. After 12 hr of incorporation, more label was found in the triacetyl and tetraacetyl bands. A significant amount of amino-acid label in the two major bands (the unsubstituted and monoacetyl bands) of histone IV was not seen until 16 hr of incubation. From 1 to 12 days, the proportion of label in the unsubstituted and monoacetylated bands increased, while that in the tetra-, tri-, and monoacetyl bands decreased. Very little [(3)H]aminoacid was found in the phosphorylated bands of histone IV in the first 12 hr. However, after 16 hr about 20% of the total (3)H was found in the phosphorylated bands. The proportion increased to 33% and remained at this level between 1 and 8 days, but, by 16 days, had decreased to 12% of the total. These data suggest that an "obligatory" acetylation of recently synthesized histone IV is involved in the correct binding of newly synthesized histone IV to DNA. We propose that epsilon-amino acetylation of lysyl residues 5, 8, 12, and 16 neutralizes their positive charges and allows the NH(2)-terminal region of histone IV to assume the correct conformation (in this case, an alpha-helix), and fit into the major groove of DNA. Deacetylation then "locks" histone IV to DNA by ionic linkages. The biological significance of phosphorylation of histone IV is not known.


Biosynthesis of acetylcholine in turtle photoreceptors. For determination of possible neurotransmitters synthesized by photoreceptor cells, turtle retinas were dissociated into single cells with proteolytic enzymes. These cells were partially separated by velocity sedimentation to yield a fraction rich in photoreceptors. Individual photoreceptor cells were then sucked into a micropipette and incubated with labeled precursors of known or suspected neurotransmitters. After incubation, the radioactive products were analyzed by high-voltage electrophoresis. Of all the chemicals tested, turtle photoreceptor cells synthesized only acetylcholine, suggesting that these cells may be cholinergic.


Drug abuse in industry--issues and comments.


Programs of the National Institute for Occupational Safety and Health.


National Institute for Occupational Safety and Health.


Research, DDT and cancer.

Research, DDT and cancer.


Automatic respiratory gas monitoring.

Automatic respiratory gas monitoring.


Letter to the editor. Warning for halothane use.


A legal approach to the physical examination.


Orofacial infection due to bacteroides, a neglected pathogen.


Depressor responses to spinal stimulation in the pithed rat. 1. Electrical stimulation of the spinal nerves in the pithed rat preparation produces a pressor response due to sympathetic vasoconstriction.2. When the vasoconstrictor effect of sympathetic stimulation is abolished by guanethidine or hexamethonium and the blood pressure is raised by noradrenaline infusion, spinal stimulation produces depressor responses or complex responses containing depressor components.3. Contractions of skeletal muscle caused by stimulation of motor nerves result in complex changes in blood pressure consisting of a pressor component due to clamping of muscle blood vessels and a secondary depressor phase due to functional hyperaemia.4. The depressor response is partly due to stimulation of cholinergic postganglionic fibres. The acetylcholine released, which causes vasodilatation, may be the overflow from neuromuscular junctions or ganglionic synapses.5. Stimulation of the nerves to the adrenal medulla causes release of adrenaline which has a vasodilator effect during noradrenaline infusion.


Median palatal cyst: report of case.

Median palatal cyst: report of case.


Fibrosarcoma of the mandible: a clinicopathologic controversy: report of case.


Decompression and secondary enucleation of a mandibular cyst: report of case.


Immediate management of facial gunshot wounds: report of case.


Carcinoma of the upper and lower lips: treatment with hyperbaric oxygenation, cobalt teletherapy, and surgical reconstruction: report of case.


Occult fracture of the odontoid process: report of case.


Meningitis as a result of a postextraction infection: report of case.


Lipoma in the infant and child: report of cases.


Antrolith: report of case.

Antrolith: report of case.


Legal aspects of public health nursing.

Legal aspects of public health nursing.


Odontogenic fibroma.

Odontogenic fibroma.


Dentigerous cysts involving the maxillary sinus.


Multiple canals in the rami of a mandible.


Dental changes in osteopetrosis.

Dental changes in osteopetrosis.


Oral extension of regional enteritis (Crohn's disease). Report of a case.


Calcifying epithelial odontogenic cyst.

Calcifying epithelial odontogenic cyst.


Oral leukoplakia in relation to tobacco habits. A ten-year follow-up study of Bombay policemen.


Palatal opening of the nasopalatine duct: a developmental anomaly. Report of a case.


Distant cutaneous metastases in a patient with squamous-cell carcinoma of the lip.


Cystic odontoma with concomitant adenoameloblastoma (adenoameloblastic odontoma).


Nonsurgical resolution of radicular cysts.


A commentary on General Bhaskar's hypothesis.


Inflammation and infection of the pulp and periapical tissues: a synthesis.


Comparison of orthopantomography with conventional periapical dental radiography.


The effect of calcium hydroxide and zinc oxide-eugenol on dentine in extracted human teeth.


Root resorption of reimplanted tooth.

Root resorption of reimplanted tooth.


Tooth under the tongue.

Tooth under the tongue.


Hepatitis-associated antigen in pregnant women.


The growth and morphology of Acholeplasma (Mycoplasma) laidlawii A in different media.


Zinc and bone healing: effect of zinc cysteamine-N-acetic acid on the healing of experimentally injured guinea pig bone.


Anaerobic gliding bacteria isolated from the oral cavity.


Intravascular clearance of endotoxin in warfarin-treated rabbits. The influence of immune serum on clearance and distribution.


Studies on bacterial surface translocation. 2. Correlation of twitching motility and fimbriation in colony variants of Moraxella nonliquefaciens, M. bovis, and M. kingii.


Preventive effect of a nonviral interferon inducer, a bacterial vaccine, on experimental influenza in mice.


Effect of a standard bacterial vaccine on infection with an obligate intracellular parasite (Toxoplasma gondii) in mice.


The implementation of a program for utilizing auxiliaries; the experience of the Indian Health Service.


Dental health knowledge and attitudes in Haiti.


Public health in the curricula for dental hygienists.


A career-ladder for educating dental personnel.


Dental utilization of a neighborhood health center.


An appraisal of the report of the Task Force on National Health Programs.


Some problems encountered in administering Head Start.


Behavioral scientists in dental research; a survey of publishing problems and prospects.


Effect of dietary linolenic acid and docosahexaenoic acid on growth and fatty acid composition of rainbow trout (Salmo gairdneri).


The immediate complete denture.

The immediate complete denture.


Marriage.

Marriage.


American Indian dentistry.

American Indian dentistry.


Tax games.

Tax games.


One way to wreck a dental practice.

One way to wreck a dental practice.


How do doctors rate the A.D.A. stand on health insurance.


"Ko on Keogh: new rules block voluntary contributions".


Dear Juli--Special patients, special problems.


A union in your future?

A union in your future?


Partnership on the rocks.

Partnership on the rocks.


Dear Juli--Handling Mamma.

Dear Juli--Handling Mamma.


The new rules on political gifts.

The new rules on political gifts.


Questions and answers about ADPAC.

Questions and answers about ADPAC.


I protest. "How now Dow Jones".

I protest. "How now Dow Jones".


Maxillary retainer with lingual arch.

Maxillary retainer with lingual arch.


Adult orthodontics.

Adult orthodontics.


Where reciprocity stands now.

Where reciprocity stands now.


Idiopathic gingival hyperlasia.

Idiopathic gingival hyperlasia.


Rhinoscleroma of the maxilla.

Rhinoscleroma of the maxilla.


Prediction of tooth size and its clinical application.


The ankylosed tooth.

The ankylosed tooth.


Biologic and physical properties of a zinc polycarboxylate cement.


Sealing composite resin restorations with a cavity sealant.


Class 3 direct-gold restoration for adolescents.


A direct pattern technique for posts and cores.


Fabrication and duplication of a temporary acrylic resin splint.


Technique for temporomandibular joint radiographs.


The relining of partial dentures involving precision attachments.


Condylar guidance settings on articulators from protrusive records.


Construction of functional occlusion in complete dentures.


Studies on lysozyme from human leucemic urine by isoelectric focusing.


Development of the anterior segment of the maxillary deciduous dentition.


The six keys to normal occlusion.

The six keys to normal occlusion.


Current application of Begg mechanics.

Current application of Begg mechanics.


Professional organizations and personal responsibilities.


A cephalometric radiography evaluation of pharyngeal flap surgery.


A biomathematical approach to craniofacial form.


Caries and plaque inhibition by mutanase in rats.


Changes in the fluoride concentration of the labial enamel surface with age.


Some population changes in oral anaerobic microorganisms, Streptococcus mutans and yeasts following irradiation of the salivry glands.


Effect of sodium lactate under conditions of neutral pH on the release of calcium from the enamel surface in vitro.


Membrane potentials in teeth: the effect of pH.


Changes in diet and dental health of children living in the Scottish Island of Lewis.


Habituation and sensitization of the flexor withdrawal reflex.


Serum vitamin B 12  and vitamin B 12  binding capacity in chronic myelogenous leukemia and other disorders.


Congenital malformations: clinic and experiment.


Certain effects of cleft palate repair on eustachian tube function.


The evaluation of arch form and occlusion in unilateral cleft palate subjects.


Sex of mouse (CDI) offspring not a factor in hydrocortisone induced cleft palate.


Pharyngeal surgery: meningitis following accidental rupture of a meningocele.


A comparison of selected cleft palate children and their siblings on the variables of intelligence, hearing loss, and visual-perceptual-motor abilities.


Correlation between functional lingual pressure and oral cavity size.


Submucous cleft palate: prevalence in a school population.


Clinicopathological conference of the medical University of South Carolina.


Acute head trauma--contraindication for lumbar puncture.


A survey of intestinal parasites in Charleston County school children.


How do we choose our future physicians?: A survey of American Medical Schools.


Anodontia of all bicuspids.

Anodontia of all bicuspids.


Smudges or dark areas appearing on radiographs.


Dental records.

Dental records.


Phosphate supplemented chewing gum.

Phosphate supplemented chewing gum.


Training program for graduates of foreign dental schools.


The apical amalgam root filling for anterior teeth.


Effects of alpha-amanitin in vivo on RNA polymerase and nuclear RNA synthesis.


Separation of alpha- and beta-globin messenger RNAs.


3-Deazauridine: crystal structure and conformation.


Amino-acid sequence homology in the muscle aldolases from sturgeons of different species.


Mechanism of accumulation of DNA in giant cells of mouse trophoblast.


E-type prostaglandins and gastric acid secretion in the rat.


Passive intercellular pathway in amphibian epithelia.


Alternative, non-immunoglobulin origin of amyloid fibrils.


Carbon monoxide poisoning: experimental hypothermic and hyperbaric studies.


The role of central nervous system irradiation in children with acute lymphoblastic leukemia.


Fungal infection in acute leukemia.

Fungal infection in acute leukemia.


Juvenile myeloid leukemia with fetal erythropoiesis.


Long-term serum copper studies in acute leukemia in children.


Osteosarcoma. An assessment of management with particular reference to primary irradiation and selective delayed amputation.


Priapism in acute lymphoblastic leukemia.


Some aspects of hypoglycemia in pediatrics.


Respirator helps tracheostomy patient to again become a fully productive employee.


The functional ultrastructure of the blood-lymph barrier. Computer analysis of data from dog heart-lymph experiments using theoretical models.


An investigation of mental morbidity in a rural county in the south of Sweden.


Ultrastructural identification of degenerating boutons of monosynaptic pathways to the lumbosacral segments in the cat after spinal hemisection.


Women and the professions.

Women and the professions.


Conferencemanship. How to conduct oneself successfully at learned meetings without actually disrupting them.


Student tutoring in preclinical technique laboratory.


AADS proposal for establishing a council of students.


Recruitment and selection of students in dentistry.


Correlation of performance in basic sciences in dental school with predental science experiences.


Student-faculty contrasts in priorities for preventive dentistry and community health programs.


Introduction to clinical dentistry--conjoint course for first-year dental students.


Fulbright lectureships.

Fulbright lectureships.


Survey of grading methods in prosthodontics in American and Canadian Dental Schools.


Auxilaries for the legal profession?

Auxilaries for the legal profession?


Update: Bourns infant ventilator.

Update: Bourns infant ventilator.


Physical evaluation of the patient presenting for implant surgery. 2.


Professional management.

Professional management.


A technique for restoring the pulpless tooth.


The riddles of education.

The riddles of education.


Pit and fissure sealants.

Pit and fissure sealants.


Clinical and morphological side-effects of busulfan (Myleran) treatment.


Oral disease control.

Oral disease control.


Peer review and you.

Peer review and you.


Relief for the fearful patient--in hypnosis.


The development of the periodontal indices.


Injured permanent incisor teeth: an epidemiological study.


Case report. Root treatment and apical curettage after 32 years.


The results of premature extraction of deciduous teeth.


A clinical pulp cap study.

A clinical pulp cap study.


Altered state of consciousness. IV. The relationship between the N2O-O2 experience and the hypnotic experience.


The dental auxiliary and oxygen-nitrous oxide conscious sedation.


A typical introduction to nitrous oxide sedation.


Signal-to-noise ratios and spatial frequency spectra of radiographic images of the bone obtained by optical and digital simulation.


Proposed legislation to create a new dental auxiliary--The Dental Technologist.


The De-Senso-Dent Ionizer: an iontophoretic instrument employing the principal of strontium and or fluoride ion transfer to hypersensitive teeth.


X-ray findings in spontaneous pneumothorax suggesting bleb formation.


Canada's oldest Olympic gold medalist.

Canada's oldest Olympic gold medalist.


A new method for the determination of biological quarternary structure by neutron scattering. Determination of quaternary structure by neutron scattering is proposed. The method gives the identity and relative spatial position of each component of a complex, provided that the complex can be obtained in deuterated form and can be reconstituted from its separated parts. If two components are rich in hydrogen and if the rest of the complex is deuterated, the contrast in scattering power permits the measurement of the separation of the pair from an interference cross term. The structure is obtained by triangulation from a set of measured pair separations.


Introducing nitrous oxide sedation to a patient for the first time.


Journey to relaxation with tranquilizing air.


Control of the rat pineal gland by light spectra. Control of pineal hydroxyindole-O-methyl transferase (S-adenosylmethionine:N-acetylserotonin-O-methyl transferase; EC 2.1.1.4) by light spectra was determined by placing groups of rats previously housed in continuous darkness under one of seven light sources for 96 hr; rats were exposed to the same intensity of irradiation. Activity of the enzyme was lowest in rats maintained under green light (lambda peak = 530 nm); blue and yellow light were somewhat less effective; red and ultraviolet light did not significantly lower the enzyme activity. The suppression of pineal hydroxyindole-O-methyl transferase by full-spectrum light sources could be correlated with the proportions of their spectral outputs in the blue-green-yellow range. These observations suggest that the retinal photopigment that mediates pineal responses to light in rats is rhodopsin or another compound with similar absorption properties.


Amino-terminal sequences and sites of in vivo acetylation of trout-testis histones 3 and IIb 2 . The sequences of the first 25 residues of histone III, and the first 22 residues of histone IIb(2), from trout testis have been determined on an automatic protein sequencer. The amino-terminal sequence of trout-testis histone III is identical to the corresponding region of calfthymus histone III, whereas the trout-testis histone IIb(2) sequence differs from that of calf-thymus histone IIb(2) at several positions in the amino-terminal region. Several in vivo sites of acetylation of these trout-testis histones have also been determined, by the same automated procedure. In addition to the two main sites at lysyl residues 14 and 23 acetylated in calf-thymus histone III, a lower degree of acetylation at two other sites, lysyl residues 9 and 18, has been detected. Four sites of acetylation have also been detected in trout-testis histone IIb(2), at lysyl residues 5, 10, 13, and 18. When the amino-acid sequences around the acetylated lysyl residues of different histones are compared, striking similarities are seen. The methods used in these studies should prove useful in elucidation of the locations of chemically stable modifications in other proteins.


Mass production of Coelomomyes, a fungus that kills mosquitoes. In work on the control of mosquitoes by the fungus Coelomomyces, the main problem is a source of inoculum since the fungus has not been cultured artificially with production of sporangia. We reared the larvae of Anopheles quadrimaculatus in algal water instead of in water with soil. By addition of inoculum once or twice in small amounts, the larvae become infected, and many grow to large fourth instars whose bodies are filled with sporangia. Such larvae are perfect for inoculum. If inoculum is added in much larger amounts and so timed that sporangia will be discharging spores during the first, second, and third ecdyses up to 100%, infection occurs, most of the larvae dying as late second or early third instars. This type of infection is good for extermination of mosquitoes but not for production of inoculum. Crude field tests have averaged 60% infection.


Association by hydrogen bonding of mononucleotides in aqueous solution. Evidence for hydrogen bonding between 5'-ribonucleotides in water has been obtained from a 220-MHz proton magnetic resonance study of nitrogenous protons. The amino groups of GMP, AMP, and CMP exhibit proton resonance lines which are somewhat broadened by proton exchange with the solvent at 0 degrees ; their downfield Shifts in mixtures of mononucleotides provide the basis for the following order of base-pairing tendencies: GMP.CMP > AMP.UMP. Hydrogen bonding is also observed in other pairs of mononucleotides, notably GMP.UMP, AMP.CMP, and CMP.UMP, to a lesser extent in GMP.IMP, CMP.XMP, and possibly in CMP.IMP. In agreement with previous reports, hydrophobic interactions of mononucleotides have also been observed; base pairing occurs in addition to vertical stacking of these bases, their hydrogen bonding to water, or self-association. Only CMP shows clear evidence of self-association via hydrogen bonding in water; the evidence for GMP is less direct, and that for AMP is negative. This lack of observable self-association may occur as a result of competition from strong stacking interactions. Only CMP shows restricted rotation of the amino group at 0 degrees and neutral pH. As expected, higher temperatures increase the rate of rotation of the amino group for CMP, as well as accelerate the rate of proton exchange between water and the amino protons of mononucleotides.High-resolution proton magnetic resonance spectroscopy could prove to be a valuable tool in mapping out the specificities conferred by hydrogen bonding between biomolecules in aqueous solution.


Sequence relationships among the variable regions of immunoglobulin heavy chains from various mammalian species. Immunoglobulin heavy chains of myeloma proteins from dogs and cata have been subjected to automated sequence analysis. When the results were compared with human heavy-chain sequences, all the dog and cat proteins could be unequivocally assigned to the V(H)III subgroup. This pattern contrasts with that in human proteins in which only 25% of all heavy chains sequenced belong to this subgroup. The 30 residues at the NH(2) termini of dog, cat, and human heavy chains had sequence identities near or exceeding 90%, in contrast to established interspecies sequence homologies of constant regions of about 60%. Some genes of the immunoglobulin heavy-chain variable region thus appear to have been conserved through a considerable period of evolutionary time. The analyses also showed that the presence of certain amino acids at certain positions in these heavy chains could be correlated with the species of origin. The occurrence of such "phylogenetically associated" residues is most consistent with the presence of a restricted number of genes in the heavy-chain variable region pool.


Rapid lateral diffusion of phospholipids in rabbit sarcoplasmic reticulum. Phospholipid spin labels incorporated in the sarcoplasmic reticulum from rabbit-skeletal muscle undergo rapid lateral diffusion within the plane of the membrane. The diffusion constant, D, is 6x10(-8) cm(2)/sec at 37 degrees . With this diffusion constant, a phospholipid molecule can diffuse a distance of the order of 5000 nm in 1 sec.


Stimulation of chondromucoprotein synthesis in chondrocytes by extracellular chondromucoprotein. Chondrocytes in suspension culture preserve their differentiated state, as expressed by a high rate of chondromucoprotein synthesis. Purified chondromuco-protein added to a suspension of cultured embryonic epiphyseal cartilage cells stimulates the rate of synthesis of chondromucoprotein at concentrations up to 2 mg/ml. The stimulation involved synthesis of the entire molecule since incorporation of labeled serine (into core protein), glucosamine, acetate, or sulfate was increased. Neither the amount of synthesis of total protein nor that of collagen was increased. No elevation of xylosyltransferase and N-acetylgalactosaminyltransferase activities was observed. The stimulation was produced by several other polyanionic substances. No evidence was found of the entry of chondromucoprotein into chondrocytes under the conditions of the experiments. Mild trypsinization lowered the response to added chondromucoprotein and decreased the endogenous rate of chondromucoprotein synthesis. Incubation of cells after trypsinization results in restoration of the rates of chondromucoprotein synthesis. The endogenous, as well as the stimulated, rate of chondromucoprotein synthesis varied with the density of chondrocytes in culture. It is suggested that the rate of chondromucoprotein synthesis may be partially controlled by cell surface receptors.


Proton magnetic resonance reveals high-spin iron (II) in ferrous cytochrome P450 cam  from Pseudomonas putida. High-resolution proton nuclear magnetic resonance spectra were studied in D(+)-camphor-saturated solutions of ferric and ferrous cytochrome P450(cam) from Pseudomonas putida, and of the cyanide complex of ferric P450(cam). In all these compounds several hyperfineshifted resonances of the heme group could be detected. In the ferrous protein, these resonance lines, which exhibit a Curie-type temperature dependence in the range of 5-28 degrees , indicate the presence of high-spin iron (II). It is suggested that the iron (II) in ferrous P450(cam) might be pentacoordinated, as in other hemoproteins that can reversibly bind molecular oxygen and carbon monoxide.


Microelectrophoretic application of cholinergic compounds, protein oxidizing agents, and mercurials to the chemically excitable membrane of the electroplax. Cholinergic compounds, protein oxidizing agents, heavy metal ions, and organic mercurials were microelectrophoretically (or electro-osmotically) applied to the innervated surface of the isolated electroplax of Electrophorus electricus. Phasic potential changes, resembling those observed under similar conditions in frog muscle, followed not only pulses of the common cholinergic drugs, but were also elicited by o-iodosobenzoate, p-chloromercuribenzoate, and Hg(++) ions. These results suggest that cholinergic receptors of both the electroplax and amphibian endplates behave in essentially the same manner. The discrepancies previously observed can be attributed mainly to the different techniques of drug application.


Serological detection of a cell-surface antigen specified by the T (brachyury) mutant gene in the house mouse. A cell-surface component specified by a mutant gene at the T-locus in the mouse has been detected on sperm by serological methods. The gene product thus recognized is not present on other adult cells.


Reactions involved in bioluminescence systems of limpet (Latia neritoides) and luminous bacteria. Luminescence in Latia involves a specific flavoprotein enzyme ("luciferase"), which has a tightly bound flavin group constituting the light-emitter. The overall reaction includes oxidation of a specific substrate ("luciferin," an enol formate derivative of an aliphatic aldehyde), by 2 O(2) molecules, in the presence of a "purple protein" cofactor, yielding a ketone, HCOOH, CO(2), and light. In Achromobacter, a required aliphatic aldehyde, which is functionally equivalent to Latia luciferin, is oxidized to an acid containing the same hydrocarbon chain as the aldehyde; this reaction proceeds in the presence of bacterial luciferase and reduced flavin mononucleotide with a quantum yield of 0.17 + 0.1 photons per aldehyde molecule that is independent of aldehyde chain length from 9 to at least 14 carbons.


Translation of messenger RNA for histones from HeLa cells by a cell-free extract from mouse ascites tumor. 7-9S RNA has been isolated from polyribosomes of HeLa S-3 cells in S phase. These RNA species direct the synthesis in vitro of all five classes of human histones when they are added to a protein-synthesizing system derived from mouse ascites tumor cells. The histones synthesized in vitro have been identified by two kinds of acrylamide gel electrophoresis, and by paper electrophoresis of tryptic digests. By use of the ratio of tyrosine to tryptophan incorporation as an index of contamination, it was determined that less than 10% of the 7-9S RNA is translated into proteins other than histones.


In vitro conversion of estradiol-receptor protein to its nuclear form: dependence on hormone and DNA. Early events in the action of 17-beta-estradiol can be studied in soluble extracts of rat uterus by exposure of the estradiol-receptor protein to a DNA-cellulose matrix. After complexing with [(3)H]estradiol, the 4S receptor protein binds to the DNA, and it can be eluted with buffer of high ionic strength as a more tightly binding, 5S form. This parallels the in vivo situation, where migration of the receptor to the nucleus follows addition of hormone and is concomitant with a similar increase in sedimentation rate to 5 S. In both cases, the formation of a 5S receptor requires the presence of 17-beta-estradiol. The rate at which 5S receptor forms is sensitive to extract concentration in a way that suggests that this receptor is a complex created by addition of a second subunit to the hormone-binding 4S component; physical studies on both in vivo and in vitro 5S receptors also support this view. These results are interpreted in terms of a model for action of estrogen in which the hormone potentiates binding of receptor to DNA, and in turn, the DNA-binding process triggers the cell response.


Coboglobins: heterotropic linkage and the existence of a quaternary structure change upon oxygenation of cobaltohemoglobin. Cobaltohemoglobin prepared from horse hemoglobin retains the full heterotropic linkage properties of the normal iron hemoglobin, including both the Bohr and phosphate effects. From this result, and the known connection between heterotropic linkage properties and hemoglobin conformational change, it is concluded that cobaltohemoglobin undergoes a quaternary structure transition upon oxygenation. Thus, the stereochemical changes that occur upon oxygen binding to cobalt, as well as to iron, must be compatible with the mechanism triggering such a transition.


Blocking by histones of accessibility to DNA in chromatin. The effect of histones on accessibility of DNA to DNase in chromatin of thymus nuclei has been studied by selective extraction of either lysine-rich or arginine-rich histones. It was found that all histones block accessibility but that, weight for weight, lysine-rich histones block much more effectively than do arginine-rich histones. We point to the contrast between accessibility of DNA to DNase and of DNA to RNA polymerase, and to what may be the similarity between accessibility to DNase and DNA polymerase.


Three-dimensional structure of L-thyroxin. The biological importance of L-thyroxin, the principal hormone secreted by the thyroid gland, is well established, but the mechanisms of thyroid-hormone action are still largely unexplained. We have crystallized L-thyroxin and determined its three-dimensional structure by x-ray crystallography in the hope that comparison of structures of active and inactive thyroid-hormone analogues will shed some light on hormone mechanisms. We compare the conformation of L-thyroxin to that of triiodo-L-thyronine, a thyroid hormone with greater activity.


Proton magnetic resonance comparison of neurohypophyseal hormones and analogs: deletion of amino groups and the conformation of lysine vasopressin. Proton nuclear magnetic resonances of two analogs of the mammalian antidiuretic hormone, lysine vasopressin, have been assigned. The analogs studied were deamino-lysine vasopressin and deamino-8-tosyllysine vasopressin, formally derived from lysine vasopressin by removal of the potential cationic sites. Most assignments made in deuterated dimethylsulfoxide at 220 MHz were directly derived from the already determined spectrum of lysine vasopression in this solvent [Walter et al., Proc. Nat. Acad. Sci. USA (1972) 69, 1920]. Comparison of chemical shifts of peptide NH peaks, alphaCH-NH coupling constants, temperature dependence of peptide NH resonances, and proton-deuterium exchange rates revealed that from a conformational standpoint both deamino analogs occupy intermediary positions between lysine vasopressin and oxytocin.


The C-group pachytene bivalent with a locus characteristic for parachromosomally situated particulate bodies (parameres): a provisional map in human males. During prophase stages of the first meiotic division in human males, an autosomal divalent in the C group (autosomes 6-12) characteristically has associated with it, at a specific locus, small, DNA-containing bodies (parameres). A pachytene chromomere map is presented, as is evidence suggesting that the parameres are disposed in two lateral loops, each of which is coaxial with one of the homologs. Stereophotographs of stacks of plates from electron micrographs of serial ultrathin sections show the parameres in their in situ configuration to be composed of tightly compacted fibrils, 85-90 A in diameter.


Nuclear magnetic resonance spectrum of lysine-vasopressin in aqueous solution and its structural implictions. The peaks in the proton NMR spectrum of lysine-vasopressin in aqueous solution at pH 3-5 were assigned to particular amino-acid residues by the use of the results of dilution studies and NH-C(alpha)H and C(alpha)H-C(beta)H decoupling experiments. The conformation of lysine-vasopressin in water differs from its conformation in dimethylsulfoxide.


Partial restoration of normal functional properties in carboxypeptidase A-digested hemoglobin. In the absence of organic phosphates human hemoglobin A digested with carboxypeptidase A (des His, Tyr beta) has high ligand affinity, a greatly reduced Bohr effect, and no heme-heme interaction. Under these conditions, it shows the simple, homogeneous ligand-binding kinetics characteristic of noncooperative heme proteins in which the high combination velocity for both O(2) and CO accounts, to a larger extent, for the increased affinity for both these ligands. Addition of inositol hexaphosphate dramatically alters the functional properties of this digested hemoglobin. The Bohr effect is greatly increased, and at neutral pH the protein shows significant, though still reduced, heme-heme interaction, together with a 5-fold decrease in affinity. In the presence of saturating amounts of the organic phosphate, the value of n is pH dependent, dropping from 1.9 at pH 5.8 to 1.3 at pH 8.6. After inositol hexaphosphate addition, the combination of the deoxy form of the digested hemoglobin with CO is 10-times slower than that observed in the absence of the inorganic phosphate; also the combination with CO after flash photolysis is biphasic and is similar, in many respects, to that observed for unmodified hemoglobin. Besides these functional changes, addition of inositol hexaphosphate to the modified deoxyhemoglobin results in an increase in the extinction coefficient at 430 nm similar to that observed on mixing the isolated alpha and beta chains of normal hemoglobin. The results are consistent with the idea that inositol hexaphosphate shifts an equilibrium between high- and low-affinity forms of the protein.


Hemoglobin switching in sheep and goats: change in functional globin messenger RNA in reticulocytes and bone marrow cells. ANEMIA CAUSES A CHANGE IN THE TYPE OF CIRCULATING HEMOGLOBIN IN GOATS AND CERTAIN SHEEP: HbA (alpha(2)beta(2) (A)) is replaced by HbC (alpha(2)beta(2) (C)). We have isolated globin mRNA from erythroid cells of anemic and nonanemic animals to investigate the mechanism whereby anemia causes this switch. To study several stages in transition from beta(A) to beta(C) synthesis, active globin mRNA was isolated from bone marrow cells, as well as from reticulocytes. By assaying these globin mRNAs in a rabbit reticulocyte cell-free system, we have demonstrated that the switch from beta(A) to beta(C) globin synthesis is mediated via a change in functional globin mRNA.


Conformation studies of various hemoglobins by natural-abundance  13 C NMR spectroscopy. Studies of variously liganded hemoglobins (both from human and rabbit) by natural-abundance (13)C NMR spectroscopy have revealed apparent conformational differences that have been interpreted on the basis of two quaternary structures for the alpha(2)beta(2) tetramer, and variable tertiary structures for the individual alpha and beta subunits. In solution, rabbit hemoglobins appear to have somewhat more flexibility than human hemoglobins.


Stereochemistry of a curare alkaloid: O,O',N-trimethyl-d-tubocurarine. The three-dimensional structure of O,O',N-trimethyl-d-tubocurarine, a neuromuscular blocking agent, has been determined by x-ray crystallography. This may help to provide insight into its pharmacologic action.


In vitro synthesis of a regulator of mammalian gene expression. Peritoneal cells isolated from guinea pigs homozygous for a deficiency of the fourth component of complement (C4), produce in vitro a factor that induces the synthesis and secretion of functionally active human C4 by a human cell. This factor appeared to switch on production of C4 in the responsive cell without affecting total protein synthesis. The regulator factor is not species specific, inasmuch as guinea pig regulator affected a corresponding human gene function. Both synthesis of the factor and the response to it were inhibited by actinomycin D. The amount of regulator recovered from genetically deficient cells was about 5-10 times that recovered from normal guinea pig cells.


Kinetics of small Ising systems: deviations from internal equilibrium in a tetrahedral model. Computer modeling is used to derive some of the exact kinetic properties of a small Ising system.


Calcium-dependent norepinephrine release from presynaptic nerve endings in vitro. Potassium concentrations above 15-20 mM in the medium, or addition of 75 muM veratridine to medium that contains 5 mM K, stimulate calcium accumulation and Ca-dependent norepinephrine release by presynaptic nerve terminals (synaptosomes) incubated in vitro. The effects of veratridine, but not of K, are blocked by 0.2 muM tetrodotoxin. This association between Ca entry and norepinephrine release is consistent with the Calcium Hypothesis of transmitter release. These results add further evidence that synaptosomes may retain many functional properties of intact presynaptic endings.


Creatine and the control of myosin synthesis in differentiating skeletal muscle. These experiments provide evidence that creatine, an end product of contraction unique to muscle, is involved in the control of muscle-protein synthesis. Skeletal muscle cells formed both in vitro and in vivo synthesize myosin heavy chain faster when supplied creatine in vitro. The response is apparent within four hours after addition of creatine to the culture medium, and is dependent on concentration over a range of 10-100 muM creatine. The effect seems to be selective for cell-specific proteins(s), since the rate of total protein synthesis is unaffected.


Simultaneous determination of viscosity and density of protein solutions by magnetic suspension. The first results are reported with a magnetic suspension instrument for determination of the viscosity and density concurrently on small volumes (0.2 ml) of protein solution. Reasonable agreement was obtained with literature values for the intrinsic viscosities and specific volumes (partial or isopotential) of serum albumin and ribonuclease in native solvents, and in 6 M guanidinium chloride with or without 2-mercaptoethanol. Turnip Yellow Mosaic virus and myosin were also studied, the results with the virus being related to hydration and structure data and those with myosin to the dissociative character of the protein. The possibility of using this approach to follow the time course of viscosity and density changes during reactions is shown.


Effects of nonpolar environments on the redox potentials of heme complexes. A method has been described for measurement of the oxidation-reduction potentials of redox couples in nonaqueous solutions. This method has been applied to a study of the effect of a nonpolar environment on the redox potential of a heme complex. A positive potential difference of some 300 mV is observed for the measured redox potentials by comparison with reported values for the corresponding heme complex in aqueous solution. The proposal is made that the redox potentials of many high-potential cytochromes may be accounted for by a local heme environment of low-dielectric constant, characteristic of nonpolar amino-acid side chains, and that this factor may play a dominant role in the determination of the oxidation-reduction properties of these proteins.


Interactions between native and chemically modified subunits of matrix-bound glycogen phosphorylase. Phospho-dephosphohybrids of rabbit skeletal muscle phosphorylase (EC 2.4.1.1; alpha-1,4-glucan: orthophosphate glucosyl transferase) have been prepared and stabilized by attachment to Sepharose activated by cyanogen bromide. They can be distinguished from phosphorylase a by their sensitivity to inhibition by glucose-6-phosphate and activation by adenosine 5'-monophosphate. Stable hybrids have also been formed between phosphorylase subunits containing the active cofactor pyridoxal-phosphate and inactive analogs (pyridoxalphosphate monomethylester or the corresponding reduced compounds). After complete dissociation to monomers, the Sepharose-bound phosphorylase had a residual activity of less than 3% of that of the original matrix-bound dimeric enzyme. The hybrid enzyme is composed of a potentially active subunit containing pyridoxal-phosphate and an intrinsically inactive subunit carrying the analog, and it had half the activity of the original dimeric enzyme. Thus, the interaction of the inactive subunit with matrix-bound phosphorylase monomers elicited activity in the monomers.


Rat brain microtubule protein: purification and determination of covalently bound phosphate and carbohydrate. Microtubule protein purified from rat brain by published procedures contains nucleic acid and carbohydrate contaminants. Microtubule protein isolated from the soluble fraction of rat brain homogenates by a new procedure contains no covalently bound amino sugars and no more than 0.2% neutral sugar, but does contain covalently bound phosphate. Total phosphate analysis of rat brain microtubule protein indicates the presence of 0.8 mol of phosphate per mol of protein dimer (110,000 g). The presence of covalently bound phosphate has been confirmed by preparation of (32)P-labeled microtubule protein from rat brain slices maintained in tissue culture in the presence of [(32)P]orthophosphate. Furthermore, phosphorylation is specific to the more negatively charged microtubule protein subunit. (32)P-Labeled serine phosphate has been identified after partial acid hydrolysis of labeled microtubule protein.


Sites of replication of chromosomal DNA in a eukaryotic cell. In mouse cells (line P815), newly synthesized DNA labeled for 20-30 sec during exponential growth is found by electron microscope autoradiography at sites throughout the cell nucleus. These sites are relatively more concentrated in the peripheral region of the nucleus (averaged over a random population of S-phase cells), probably reflecting a higher local concentration of DNA in this region. Newly synthesized DNA is not preferentially associated with purified nuclear envelopes, but is found in a fraction of the chromosomal deoxynucleoprotein whose buoyant density in CsCl after formaldehyde treatment is about 1% lower than that of the deoxynucleoprotein peak. Kinetics experiments suggest that this material is a precursor of mature deoxynucleoprotein; it may represent regions of deoxynucleoprotein containing replicating DNA and the additional proteins involved in DNA replication. Other complexes of newly replicated DNA that are found in the interphase after phenol extraction of nuclei are formed during the extraction procedure, probably due to the partially single-stranded nature of replicating DNA, and do not appear to exist in vivo.


Resolution of a spectrum of nucleoprotein species in sonicated chromatin. Sonicated rabbit-liver chromatin is fractionated by ion-exchange chromatography on ECTHAM-cellulose, a weakly cationic adsorbent. The chromatographic procedure provides a series of fractions having a spectrum of thermal denaturation profiles. The earliest-eluting fractions melt cooperatively at a significantly higher temperature than bulk chromatin, and totally lack any of the components of chromatin that melt at low temperatures. In contrast, the latest-eluting fractions are significantly enriched in their content of DNA sequences that melt at low temperatures. Although the protein to DNA mass ratio of all fractions is equal to that of unfractionated chromatin, polyacrylamide gel electrophoresis demonstrates that the relative amounts of individual proteins vary across the chromatographic peak. The most pronounced changes observed are the enrichment of a particular high molecular weight nonhistone protein in the later fractions, and a significant diminution of lysine-rich histone in the last fractions. The results, in conjunction with the demonstration by McConaughy, B. L. & McCarthy, B. J. (Biochemistry 11, 998-1003, 1972) that RNA transcribed in vivo in immature chick erythrocytes hybridizes to the DNA of only the portions of chromatin from these cells that melt at low temperatures, suggest that this fractionation may separate transcribable DNA sequences in chromatin from the repressed segments of a eukaryotic genome.


Transamidase reactions involved in the enzymic coagulation of semen: isolation of  -glutamyl- -lysine dipeptide from clotted secretion protein of guinea pig seminal vesicle. New supportive evidence is advanced in favor of the hypothesis that the enzymic coagulation of guinea pig semen involves transamidase reactions that result in the formation of gamma-glutamyl-epsilon-lysine intermolecular cross linkages between molecules of a basic protein in seminal vesicle secretion. The dipeptide gamma-glutamyl-epsilon-lysine was isolated in large quantities from proteolytic digests of the coagulated basic vesicular secretion protein that comprises the seminal clot.


Control of daughter-cell number variation in multiple fission: genetic versus environmental determinants in Prototheca. Prototheca zopfii has been developed as an experimental system for studying the control of cytokinesis and daughter-cell number variation in multiple fission. Although mean daughter-cell number increases linearly with growth rate, and this dependency is genetically controlled, pedigree analysis shows that daughter-cell number variation is not under direct genetic control. In a population growing in steady-state balanced growth, each cell has a given probability of dividing into 2, 4, 8 16, or 32 daughter-cells. These probabilities are independent of the division number of the cell in the preceding generation, and can be altered by changes in the culture medium.


Care and treatment of malpositioned teeth. Surgical-orthodontic repositioning of impacted canines.


Foreign body in a root canal.

Foreign body in a root canal.