Proceedings: Regulatory changes in the activity of L-serine: pyruvate aminotransferase and its response to cyclic AMP and cortisone in regenerating rat liver.


Proceedings: Binding constants of nicotinamide nucleotides to native and modified (tyrosine residue) lactate dehydrogenase.


Proceedings: On the action of dipyridamole (persantin) on partially purified myocardial adenosine kinase.


Proceedings: Biosynthesis of nicotinamide adenine dinucleotide in mitochondria.


Proceedings: Increased receptor affinity as basis for the enhanced biological activity of turkey insulin.


Proceedings: Binding of luteinizing hormone to functional collagenase-isolated testicular interstitial cells.


Proceedings: Purification and characterization of an endonuclease from adenovirus-infected cells.


Proceedings: Effect of adenosine 3':5'-monophosphate on active amino acid transport in Streptomyces hydrogenans.


Proceedings: Juvenile hormone-binding macromolecules in insect organs.


Proceedings: Influence of concanavalin A on nucleic acid and protein synthesis in growing baby hamster kidney-21 cells.


Proceedings: Protein-lipid and protein-protein interaction in recombined lipoprotein membranes.


Proceedings: Isoenzymes of hexosediphosphatase in small intestinal epithelium.


Proceedings: Oestrogen receptor content and hormone-responsive growth of mouse mammary tumours.


Proceedings: Nucleotide sequence analysis of the SV40 - hind H DNA fragment.


Proceedings: Synthesis and secretion of albumin and angiotensinogen by isolated rat liver cells.


Proceedings: Precursors of cytochrome oxidase in cytochrome-oxidase deficient cells of Neurospora crassa.


13-C nuclear magnetic resonance spectroscopic studies on lipid-protein interactions in human high-density lipoprotein (HDL). A model of the HDL particle.


Effects of thiophosphate analogues of ATP and ADP on the ATP-synthetase reaction of oxidative phosphorylation.


Purification of a phosphodiesterase from the thermophilic fungus Talaromyces duponti.


3':5'-cyclic-AMP phosphodiesterase from Trypanosoma gambiense.


A procedure for the isolation of Dictyostelium nuclei.


Cytolytic properties of phallolysin.

Cytolytic properties of phallolysin.


Ganglioside accumulation by transformed murine fibroblasts (3T3) cells and canine erythrocytes.


The role of the glycerolphosphate shuttle in heterogenous liver mitochondria.


Mechanism of the increased biological activity of turkey insulin.


A model for mutual excitation in a neuron population in olfactory bulb.


Mechanism of action of anesthetic gases.


Neuropharmacology of anesthetics.

Neuropharmacology of anesthetics.


Some effects of inhalation anesthetics on neurocirculatroy control.


A simple qualitative spot complementation test for temperature-sensitive mutants of SV40.


Infection of EBV-genome-negative and -positive human lymphoblastoid cell lines with biologically different preparations of EBV. Epstein-Barr virus (EBV) derived from the B95-8 line has transforming activity for cord blood cells, whereas virus derived from the P3HR-1 line lacks such activity. When the two viral preparations were compared for their ability to infect the same EBV-genome-negative lymphoblastoid cell line, BJA-B, they induced approximately the same number of EBV-determined nuclear antigen (EBNA)-positive cells. EBNA is compatibile with continued cell proliferation. No early antigen (EA)-positive cells appeared in the B95-8 virus-infected cultures, whereas P3HR-1 virus-infected cells went on to express EA. EA signals the entry of the cell into the lytic cycle. No late viral antigen (VCA) appeared and, as a consequence, the P3HR-1 virus infection became abortive. In contrast, the EBNA-positive cells induced by the B95-8 virus continued to divide over several weeks. These findings show that different EBV isolates may differ in their biological activity, probably due to their having different degrees of viral dependence on restrictive host cell controls.


Acquisition of malignant properties by SV40-transformed mouse cells: relationship to type-C viral antigen expression. BALB/c mouse embryo cells morphologically transformed by papovavirus SV40 initially failed to produce tumors in immunocompetent or immunosuppressed syngeneic newborn or adult mice. Prolonged in vitro cultivation was required for the transformed cells to produce tumors in the immunosuppressed host. The level of expression of murine leukemia virus gs antigen in transformed cells did not increase until the transformed cells had undergone four or five in vivo passages suggesting that the malignant property of the transformed cells is expressed independently of the murine leukemia virus gs antigen.


Efficiency of translation of viral and cellular mRNA's in extracts from cells infected with encephalomyocarditis virus. The relative efficiency of translation of host cell mRNA and encephalomyocarditis (emc) virus RNA has been investigated in cell-free preparations from uninfected and EMC virus-infected Drebs-II cells. The ability of cell-free extracts from infected cells to translate exogenously-added EMC virus RNA and total Krebs-II cell mRNA was markedly diminished, but no evidence for the selective inhibition of translation of host cell mRNA in these systems was obtained.


A guanidine-sensitive step of the poliovirus RNA replication cycle. It has been shown that the amount of viral RNA synthesized in synchronized HeLa cells 0-2 h after infection does not notably vary during the mitotic cycle. However, the amount of viral RNA synthesized 2-4.5 h after infection exhibited a sharp maximum in S-phase cells. Guanidine inhibited the incorporation of 3-H-uridine into the viral RNA synthesized 2-4.5 h after infection only in cells in the S-phase. It had no demonstrable effect on viral RNA synthesis 0-2 h after infection in cells in any phase of the mitotic cycle. Thus, additional indirect evidence has been presented in favor of the hypothesis that two different replicases or two different conformations of one enzyme are involved in poliovirus RNA replication. The one functioning 0-2 h after infection is cycle-independent and guanidine-sensitive, whereas the other functions exclusively in phase-S cells 2-4.5 h after infection and is inhibited by guanidine.


Morphological components of herpesvirus. I. Intercapsomeric fibrils and the geometry of the capsid. Highly purified equine herpesvirus type 1 (EHV-1) and herpes simplex virus type 1 (HSV-1) were observed by electron microscopy in various stages of disintegration. Under the conditions used, envelopes of virions usually were fragmented, and virus capsids collapsed in situ into flattened sheets of capsomeres. A matrix of intercapsomeric fibrils was observed. Evidence suggesting that the capsid hexamer has threefold structural symmetry is presented.


Inhibition of cardiolipin synthesis following infection with herpes simplex virus. The results of this study show that the synthesis of the inner mitochondrial membrane phospholipid, cardiolipin, is markedly inhibited following infection of human embryonic lung or hamster embryo fibroblast cells with herpes simplex virus type 1 or 2. The synthesis of other phospholipids, i.e., phosphatidylcholine, phosphatidylethanolamine, sphingomyelin, and phosphatidylinositol, is relatively unaffected.


Calciferol and its relatives. (part)XVIII. Total synthesis of 1alpha-hydroxy vitamin D3.


The action of topical vitamin A acid on normal epidermis and non-involved epidermis of psoriatics. A morphological and enzymatic study.


Intramitochondrial crystalloid inclusions in neuronal processes of human cerebral cortex.


Bovine gingival collagenase: demonstration and initial characterization. A collagenase active against native collagen was found in culture fluids of bovine gingiva. The enzyme first appeared in the culture fluid after 1-2 days and could be harvested thereafter for at least 30 days. The collagenase attacked collagen fibrils and cleaved collagen in solution, resulting in reaction products 1/4 and 3/4 of the length of the original molecule. The enzyme was inhibited by serum, by EDTA and by cysteine. The molecular weight was estimated by gel filtration to be 63,000 daltons.


Hormones and human sleep.

Hormones and human sleep.


Recent developments in monoamine histochemistry.


Endycytosis and exocytosis: role of microfilaments and involvement of phospholipids in membrane fusion.


The origin of mRNA and the structure of the mammalian chromosome.


The mechanism of impulse generation in excitable cells.


Physical properties of the lipid phase of membranes from cultured animal cells.


Lipid phase separations and protein distribution in membranes.


Molecular interactions in the bacterial phosphoenolpyruvate-phosphotransferase system (PTS).


Immunological surveillance against neoplasia.


Standard of care in medical malpractice cases.


The possible role of eye-muscle potentiation in several forms of prism adaptation.


Estimation of low density lipoprotein fraction concentration in blood plasma of laying turkey hens using density gradient centrifugation.


The problem of postmaturity.

The problem of postmaturity.


Methaqualone and peripheral neuropathy.

Methaqualone and peripheral neuropathy.


Phytochrome, a photochromic sensor.

Phytochrome, a photochromic sensor.


Enzymatic and nonenzymatic bioluminescence.


Effects of x-irradiation of pupae on aging of the thoracic flight muscle of the adult house fly Musca domestica L.


The role of light in nitrate metabolism in higher plants.


Effect of age on ultrastructural changes of cortisone treated mouse hepatic cells.


Action of neuraminidase from Clostridium perfringens of Tay-Sachs ganglioside.


Anomalies in the tRNA-aminoacylation reaction which could lead to misinterpretation of evidence for tRNA changes during development and aging.


Uptake of RNA fragments from ribosomal subunits by Novikoff hepatoma ascites cells.


The effect of ADP and Mg++ ions on the interaction between mitochondrial cytochrome oxidase and exogenous cytochrome c.


Estrogen stimulated pathway changes and cold-inactivated enzymes.


Oxidation of S-carboxymethyl-L-cysteine by glutamate dehydrogenase.


Regulation of hepatic glycogen synthetase of Rana catesbeiana.


Effect of ethionine on the synthesis and transfer of active methyl groups.


On the histobiological trend in the investigation of neuroectodermal tumours.


Serum lipoproteins changes in certain internal diseases. Disc electrophoretic study.


The hepatoprotecting action of methylthiouracil and carbimazol on the evolution of experimental chronic hepatitis.


A comparative study of the efficacy of inhaled beclomethasone and systemic prednisolone in bronchial asthma.


Congenital stationary nightblindness.

Congenital stationary nightblindness.


Electron microscopic histochemical studies of cyclic 3', 5'-nucleotide phosphodiesterase in the developing retina of normal mice and mice with hereditary retinal degeneration.


Isolation of 32P-labeled phosphorylserine and phosphorylthreonine from Ehrlich mouse ascites tumor cells suspended in different isotonic media containing 32P-labeled adenosine triphosphate.


Substrate incorporation into lipids and proteins in human liver slices. An experimental study with special reference to dyslipoproteinemic conditions.


Modulation of tRNA methyltransferase activity by competing enzyme systems.


Studies on an intravenous fat tolerance test. Methodological, experimental and clinical experiences with Intralipid.


Operation of pleiotropic control in hormonal regulation and in neoplasia.


Abnormalities in adenyl cyclase in psoriasis, a hyperproliferative skin disease.


Hormone receptors. IV. Solubilization and purification of a liver plasma membrane glucagon-binding protein.


DNA polymerases in normal and regenerating rat liver and hepatomas: targets for chemotherapy.


Biosynthesis of uridine-5'-monophosphate in rat liver and Morris hepatomas.


New aspects of the mechanism and regulation of pyridine nucleotide metabolism.


Regulation of carbohydrate and lipid metabolism in the liver and adipose tissue of normal and diabetic mice.


Magnesium, a second messenger for insulin: ion translocation coupled to transport activity.


Hormonal control of tRNA methyltransferases and of tRNA structure.


Specificity of Bordetella endotoxins in bactericidal systems.


Aetiological changes in acute infectious clinical pictures.


Determination of moisture content of freeze-dried products by tritium isotope.


Effect of antiviral agents in equine abortion virus-infected hamsters. Equine abortion virus, a member of the herpesvirus group, produces a lethal infection in hamsters. With this system, the protective effect of certain inhibitors of deoxyribonucleic acid viruses, inducers of interferon and exogenous interferon, was evaluated. Of the various agents studied, 9-beta-d-arabinofuranosyladenine markedly suppressed mortality, and 5-iodo-2'-deoxyuridine, distamycin A, and N-ethylisatin beta-thiosemicarbazone were inactive. Of the inducers tested, statolon, ultraviolet-irradiated Newcastle disease virus, and polyriboinosinic:polyribocytidylic acid (poly I:C) were protective, and endotoxin, polyacrylic acid, and polymethacrylic acid did not protect. Administration of exogenous interferon did not afford protection. Statolon and ultraviolet-irradiated Newcastle disease virus induced circulating interferon in hamsters, whereas poly I:C, endotoxin, and polyacrylic acid did not produce interferon. Because of the severity of the disease produced in hamsters by equine abortion virus, lack of protective activity by an agent in this system should not preclude possible efficacy against other members of the herpesvirus group.


Congocidine and distamycin A, antipoxvirus antibiotics. The antibiotics congocidine and distamycin A inhibited the replication of Shope fibroma and vaccinia viruses in BSC(1) cells. Treatment of infected cultures with congocidine for a 12-hr period resulted in an irreversible inhibitory effect on virus development. A longer period of treatment with the antibiotic also resulted in inhibition of the residual infectious virions present in the treated cells. Distamycin A inhibited the replication of poxviruses, but its inhibitory effect was reversed when the antibiotic was removed from the infected cells even as long as 24 hr after treatment. The inhibitory effect of distamycin A and its reversibility resembled the antipoxvirus activity of rifampin.


Mechanism of the antiviral action of 3-methyleneoxindole. The biochemical basis underlying the antiviral action of 3-methyleneoxindole (MO), a plant metabolite, was examined in HeLa cells infected with poliovirus. In the presence of antiviral concentrations of MO, poliovirus-specific ribonucleic acid (RNA) synthesis can proceed normally, and the RNA synthesized under such conditions is infectious. It is suggested that the ability of MO to bind to ribosomes of HeLa cells may underlie the antiviral affect. Data are presented which indicate that poliovirus messenger RNA cannot attach to those ribosomes which already are bound to MO. Consequently, virus-specific polysomes cannot be recovered from infected cells treated with antiviral concentrations of MO. In contrast, antiviral concentrations of MO do not prevent the formation of polysomes in uninfected HeLa cells.


Glycolytic enzymes in E. histolytica.

Glycolytic enzymes in E. histolytica.


A comparison of the virulence of nine strains of axenically cultivated E. histolytica in hamster liver.


Pathogenicity of E. histolytica.

Pathogenicity of E. histolytica.


Observations on the persistence of antibodies to E. histolytica.


Studies in nocturnal migraine.

Studies in nocturnal migraine.


Studies on the structure and activity of rabbit Clq (a subcomponent of the first component of complement). 1. The subunit structure of rabbit subcomponent C1q was examined in a previous publication (Reid et al., 1972). The present paper describes some aspects of the structure of the polypeptide chains derived from the molecule. 2. The three polypeptide chains, produced by performic oxidation, of rabbit subcomponent C1q were isolated by ion-exchange chromatography in 8m-urea on DEAE-cellulose. 3. Each chain was found to contain 15-18% glycine and significant amounts of the amino acids hydroxyproline and hydroxylysine. 4. By means of collagenase digestion it was shown that all three chains of rabbit subcomponent C1q contain collagen-like sequences of amino acids which constitute about 40% of each chain. 5. By use of carboxypeptidase A it was established, indirectly, that the collagen-like sequences, in one of the chains, are probably located near, or at, the N-terminal end of the chain. 6. Collagenase digestion and heating at 52 degrees C (but not at 49 degrees C) caused rapid loss of native rabbit subcomponent C1q haemolytic activity.


Studies on chemical modification of thionucleosides in the transfer ribonucleic acid of Escherichia coli. (35)S-labelled tRNA from Escherichia coli was treated with chemical reagents such as CNBr, H(2)O(2), NH(2)OH, I(2), HNO(2), KMnO(4) and NaIO(4), under mild conditions where the four major bases were not affected. Gel filtration of the treated tRNA showed desulphurization to various extents, depending on the nature of the reagent. The treated samples after conversion into nucleosides were chromatographed on a phosphocellulose column. NH(2)OH, I(2) and NaIO(4) reacted with all the four thionucleosides of E. coli tRNA, 4-thiouridine (s(4)U), 5-methylaminomethyl-2-thiouridine (mnm(5)s(2)U), 2-thiocytidine (s(2)C) and 2-methylthio-N(6)-isopentenyladenosine (ms(2)i(6)A), to various extents. CNBr, HNO(2) and NaHSO(3) reacted with s(4)U, mnm(5)s(2)U and s(2)C, but not with ms(2)i(6)A. KMnO(4) and H(2)O(2) were also found to react extensively with thionucleosides in tRNA. Iodine oxidation of (35)S-labelled tRNA showed that only 6% of the sulphur was involved in disulphide formation. Desulphurization of E. coli tRNA with CNBr resulted in marked loss of acceptor activities for glutamic acid, glutamine and lysine. Acceptor activities for alanine, arginine, glycine, isoleucine, methionine, phenylalanine, serine, tyrosine and valine were also affected, but to a lesser extent. Five other amino acids tested were almost unaffected. These results indicate the fate of thionucleosides in tRNA when subjected to various chemical reactions and the involvement of sulphur in aminoacyl-tRNA synthetase recognition of some tRNA species of E. coli.


A comparison of wild-type and mutant ribitol dehydrogenases from Klebsiella aerogenes. A ribitol dehydrogenase (ribitol-NAD(+) oxidoreductase, EC. 1.1.1.56) having increased specificity and catalytic efficiency toward xylitol was isolated from mutant strains of Klebsiella aerogenes, which were selected for increased growth rate on xylitol over the ribitol dehydrogenase constitutive wild-type organism. 2. The mutant enzyme was purified to homogeneity and its general characteristics were compared with those of the previously purified wild-type enzyme. 3. Initial-velocity steady-state kinetic parameters were determined for both wild-type and mutant enzymes and the results compared. 4. The results are interpreted in terms of a model in which the mutant enzyme results from a small change of amino acid sequence, which affects both the stability and conformational equilibria of the molecule.


The copolymeric structure of pig skin dermatan sulphate. Isolation and characterization of L-idurono-sulphate-containing oligosaccharides from copolymeric chains. Dermatan sulphate was degraded by testicular hyaluronidase and an oversulphated fraction was isolated by ion-exchange chromatography. This preparation, which contained fairly long segments derived from the non-reducing terminal portion of the molecule, was subjected to periodate oxidation under acidic conditions. The oxidized iduronic acid residues were cleaved by reduction-hydrolysis (Smith-degradation) (Fransson & Carlstedt, 1974) or by alkaline elimination. The oligosaccharides so obtained contained both GlcUA (glucuronic acid) and IdUA-SO(4) (sulphated iduronic acid) residues. Copolymeric oligosaccharides obtained after alkaline elimination were cleaved by chondroitinase-AC into disaccharide and higher oligosaccharides. Since the corresponding oligosaccharides obtained by Smith-degradation were unaffected by this enzyme, it was concluded that the carbohydrate sequences were GalNAc-(IdUA-GalNAc)(n)-GlcUA-GalNAc. The iduronic acid-containing sequences were resistant to digestion with chondroitinase-ABC. It was demonstrated that the presence of unsulphated N-acetylgalactosamine residues in these sequences could be responsible for the observed effect. This information was obtained in an indirect way. Chemically desulphated dermatan sulphate was found to be a poor substrate for the chondroitinase-ABC enzyme. Moreover, digestion with chondroitinase-ABC of chondroitinase-AC-degraded dermatan sulphate released periodate-resistant iduronic acid-containing oligosaccharides. It is concluded that copolymeric sequences of the following structure are present in pig skin dermatan sulphate: [Formula: see text] N-acetylgalactosamine moieties surrounding IdUA-SO(4) residues are unsulphated to a large extent.


Kinetic studies on oxidized nicotinamide--adenine dinucleotide-facilitated reactions of D-glyceraldehyde 3-phosphate dehydrogenase. The kinetics of the acylation of d-glyceraldehyde 3-phosphate dehydrogenase from pig muscle by 1,3-diphosphoglycerate in the presence of NAD(+) has been analysed by using the relaxation temperature-jump method. At pH7.2 and 8 degrees C the rate of acylation of the NAD(+)-bound (or holo-) enzyme was 3.3x10(5)m(-1).s(-1) and the rate of phosphorolysis, the reverse reaction, was 7.5x10(3)m(-1).s(-1). After a temperature-jump perturbation the equilibrium of NAD(+) binding to the acyl-enzyme was re-established more rapidly than that of the acylation. The rate of phosphorolysis of the apoacylenzyme from sturgeon muscle and of aldehyde release from the d-glyceraldehyde 3-phosphate-apoenzyme complex were </=40m(-1).s(-1) and </=12s(-1) respectively at pH8.0 and 22 degrees C, which means that both processes are too slow to contribute significantly to the reaction pathway of the reversible NAD(+)-linked oxidative phosphorylation of d-glyceraldehyde 3-phosphate. Phosphorolysis of both acyl-apoenzyme and acyl-holoenzyme was first-order in P(i) up to 100mm-P(i) and more. PO(4) (3-) could be the reactive species of the phosphorolysis of the acyl-holoenzyme, in which case phosphorolysis is a diffusion-controlled reaction, although other kinetically indistinguishable rate equations for the reaction are possible.


An inhibitor of phospholipase D in saliva. 1. Bovine, dog and human saliva contain substances which inhibit the soluble phospholipase D present in grass leaf or celery stalk. 2. The inhibitor in bovine saliva is of high molecular weight and exhibits considerable stability to heat, acids and alkalis. 3. The inhibitor has been purified free from salivary mucoprotein. 4. It is suggested that the inhibitor could protect the upper alimentary tract of a herbage-eating animal from the necrotic action of phospholipase D.


Deoxycytidylate deaminase evidence for a new enzyme in cells infected by the virus of herpes simplex. The activities of dCMP deaminase and DNA polymerase I increased twofold and fivefold in BHK-21/C13 cells after infection by the virus of herpes simplex. The increases were greatly diminished, and under certain conditions prevented, by inclusion of actinomycin D or cycloheximide in the cell-virus system during the infective cycle. The dCMP deaminase purified from infected cells harvested 8h after infection differed from the deaminase purified from non-infected cells inasmuch as (a) it was more resistant to heating at 37 degrees C; (b) the substrate (dCMP) concentration at half-maximum velocity was lower; (c) maximum activation was achieved by a lower concentration of dCTP; (d) it was more resistant to inhibition by dTTP; and (e) it behaved differently when assayed in the presence of a herpes-virus-specific antiserum. The DNA polymerase activity in the infected cells was markedly decreased in the presence of the herpes-virus-specific antiserum.


The preparation of crystalline human L-lactate--nicotinamide--adenine dinucleotide oxidoreductase isoenzyme 1 involvoing preparative polyacrylamide-gel electrophoresis. A method is presented for the preparation of human heart lactate dehydrogenase (l-lactate-NAD(+) oxidoreductase; EC 1.1.1.27) isoenzyme 1; this involves the use of polyacrylamide-gel electrophoresis as a preparative step. The yield was about 10% with a final specific activity of 220 units/mg of protein, one unit being defined as the amount of enzyme catalysing the oxidation of 1mumol of NADH/min at 25 degrees C, in the presence of 0.33mm-pyruvate. The crystalline preparation contained less than 2% of the other isoenzymes, was homogeneous in the ultracentrifuge and showed only a trace of protein contamination on polyacrylamide-gel electrophoresis. Some properties of the crystalline isoenzyme are reported; E(1%) (1cm)=13.2 at 280nm, s(0) (20,w)=7.43S, pI=4.6, and the apparent K(m) for pyruvate=1.02x10(-4)m. The human isoenzyme and the isoenzyme from pig heart differ with respect to amino acid composition, electrophoretic mobility and solubility. It is possible that these differences do not involve the active site, or sites, but are due to changes in amino acid residues elsewhere in the molecule. The importance of purified human LDH-1 isoenzyme with regard to enzyme radioimmunoassay is emphasized.


Protection of glutamate dehydrogenase by nicotinamide-adenine dinucleotide against reversible inactivation by pyridoxal 5'-phosphate as a sensitive indicator of conformational change induced by substrates and substrate analogues. 1. The steady residual activity of ox liver glutamate dehydrogenase at equilibrium with the reversible inactivator pyridoxal 5'-phosphate was measured in the presence and absence of various protecting agents. 2. NAD(+) (up to 15mm) and its 3-acetylpyridine analogue (up to 5mm) both failed to protect, in contrast with NADH. 3. Partial protection was given by glutarate and by succinate. Adipate and pentanoate were much less effective. 4. Correspondingly, whereas succinate and glutarate were both shown to be strong inhibitors of the catalytic reaction, competitive with glutamate, adipate was only weakly competitive, and the still weaker inhibition by pentanoate was non-competitive. 5. When the enzyme was saturated with glutarate, NAD(+) became a good, although still partial, protecting agent. In the absence of protection, 1.8mm-pyridoxal 5'-phosphate decreased enzyme activity to 9%, in the presence of 150mm-glutarate to 29%, and with glutarate and 1mm-NAD(+) only to 73%. 6. 2-Oxoglutarate also promoted protection by NAD(+), but neither pentanoate nor succinate did so. The finding with succinate is remarkable in view of findings 3 and 4 above. 7. It seems possible that substrates or analogues possessing the glutarate structure promote a conformational change that alters the mode of NAD(+) binding. This may explain why glutamate is a much better substrate than norvaline or aspartate and why negative interactions in coenzyme binding occur only in the formation of ternary complexes with glutamate or its analogues.


Nuclear protein kinase activity in glucagon-stimulated perfused rat livers. Nuclei isolated from glucagon-stimulated perfused rat livers contained 2-3 times as much protein kinase activity as did nuclei from control animals. In the presence of either the heat-stable inhibitor or the protein kinase regulatory subunit the elevated cyclic AMP-independent enzyme activity from stimulated nuclei was inhibited to an activity equivalent to that found in controls.


Electron-paramagnetic-resonance studies on cobalt(II) carbonic anhydrase-sulphonamide complexes. Sulphonamide adducts of three Co(II) carbonic anhydrases were investigated by e.p.r. (electron paramagnetic resonance) at helium temperatures. The highly anisotropic 9 GHz spectra exhibited only three distinct features, with g values between 6.3 and 1.5. Such spectra arise from an electronic state with effective spin S'=(1/2), indicating that the high-spin (S=3/2) ground level is split into two spin doublets differing in energy by an amount large compared with the microwave quantum, but small in relation to thermal energies at ambient temperature. This situation would occur in a tetrahedral system suffering a large rhombic distortion. Calculations based on this model accounted for apparent discrepancies in integrated spectral intensities, and yielded magnetic moments in good agreement with independent measurements, especially in the case of certain small Co(II) complexes resembling the enzyme adducts in their e.p.r. signals. Precise sets of g values, reflecting a particular co-ordination geometry, were found to be representative of each enzyme variant and the type of sulphonamide inhibitor, whether benzocyclic or heterocyclic. A series of substituted benzene sulphonamides bound to the same enzyme gave rise to closely similar spectra despite a wide range of pK(i) values. Thus benzocyclic and heterocyclic sulphonamides were evidently held in the active-site cleft in characteristic orientations irrespective of side chains that might considerably influence the total binding strength. Visible absorption spectra of various sulphonamide adducts at room temperature showed a similar pattern of inhibitor dependence to the e.p.r. spectra, suggesting a correspondence between the co-ordination structures in liquid and frozen solution. E.p.r. spectra of the sulphonamide complexes were remarkable not only for their range of g values, but also for their variations in line-width and spin-lattice relaxation behaviour. Addition of glycerol to the medium produced marked enhancement in resolution, owing to the creation of a more homogeneous frozen matrix. The non-uniform spin relaxation was probably a consequence of the large anisotropy in effective g tensor.


Properties of pig heart aconitase.

Properties of pig heart aconitase. Comparison of pig heart aconitase (Kennedy et al., 1972) with yeast (Candida lipolytica) aconitase (Suzuki et al., 1973) reveals similarities in molecular weight and iron content but not in sulphide content. Comparison with the Mildvan & Villafranca (1971) pig heart aconitase preparation reveals differences in iron ligands, specific activity and other properties; these differences possibly arise from protein association as pig heart protein associates under a variety of conditions. The electron spin resonance spectrum, g 4.25, and the low molar relaxivity, 473m(-1).s(-1), of water H(+) suggest the presence of high-spin Fe(III) unco-ordinated to water in the enzyme. The iron chromophore on acid titration at 320nm gives a curve with an inflexion at pH4.2. Ten of 16 expected thiol equivalents are titrated with p-hydroxymercuribenzoate suggesting the presence of cystine as well as cysteine residues. Inhibition of the activation of inactive (activatable) enzyme is sigmoidally related to the molar ratio, p-hydroxymercuribenzoate/enzyme with 10-11mol of mercurial compound causing complete inhibition. Active enzyme, free from activating reagents, requires high molar ratios of mercurial compound for rapid inhibition. In terms of p-hydroxymercuribenzoate the enzyme then lacks an essential thiol group.


Inhibition of the soluble adenosine triphosphatase from mitochondria by adenylyl imidodiphosphate. 1. Adenylyl imidodiphosphate is an inhibitor with high affinity for the soluble ATPase (adenosine triphosphatase) from mitochondria. 2. The reaction of the inhibitor with the ATPase is slow and estimates for the association and dissociation reaction rate constants are given. 3. The number of binding sites for the inhibitor appears to be doubled in the presence of 2,4-dinitrophenol. 4. Adenylyl imidodiphosphate is less effective as an inhibitor of the ATPase activity of this enzyme than of the inosine triphosphatase activity. It is also less effective on the ATPase of frozen-thawed or intact mitochondria and did not inhibit ADP-stimulated respiration by intact mitochondria.


Mössbauer effect in the 'super-reduced' form of the high-potential iron-sulphur protein from Chromatium. Mössbauer-effect studies of the super-reduced form of Chromatium high-potential iron-sulphur protein indicate that the iron atoms are in a similar valency state to those in reduced ferredoxin from Clostridium pasteurianum, with possibly some inequivalence between the iron atoms within the four-iron centre. Mössbauer spectroscopy also shows magnetic differences between the four-iron centres in the two proteins.


Activities of prolyl hydroxylase, lysyl hydroxylase, collagen galactosyltransferase and collagen glucosyltransferase in the liver of rats with hepatic injury. The activities of four enzymes catalysing post-translational modifications of the collagen polypeptide chains were assayed in the livers of rats with experimental hepatic injury. The liver injury was induced by injecting carbon tetrachloride twice weekly, and assays of the enzymic activities were carried out 2 and 4 weeks after commencement of administration of carbon tetrachloride. The liver homogenates were preincubated with Triton X-100 before the assays, because such treatment was found to increase the activities of all four enzymes in the supernatants of liver homogenates. The activities of all four enzymes had increased by 2 weeks after commencement of carbon tetrachloride administration. No increase was found in the collagen content of the livers at this stage and thus an increase in all four enzyme activities preceded an increase in the collagen content of the liver. A further slight increase was found in three of the enzyme activities during the subsequent 2 weeks of the experiment, whereas no further increase was found in the collagen galactosyltransferase activity. A statistically significant correlation was found between all four enzyme activities, but the magnitude of the increases varied considerably. The largest increase was found in lysyl hydroxylase activity, and at 4 weeks the magnitude of this was about three times that of the collagen galactosyltransferase activity. The results thus indicate that the increased enzyme activities cannot be explained simply by an increase in the number of collagen-producing cells having similar enzyme activity patterns to those of the cells initially present in the liver.


Glucose transport in Entamoeba histolytica. That the uptake of glucose by the parasitic amoeba Entamoeba histolytica occurs by an equilibrative transport system is supported by the following observations. 1. The rate of glucose uptake is several orders of magnitude greater than the uptake by pinocytosis. 2. The uptake of glucose exhibits saturation kinetics, with K(m)=1.6mm and V(max.) ranging from 2 to 5mumol/min per ml of cells at 37 degrees C. 3. The glucose analogues 2-deoxyglucose, 3-O-methylglucose and d-xylose are transported by the glucose system although with much less affinity. Competitive inhibition was observed between pairs of substrates, with K(i) values for any sugar closely coincident with the corresponding K(m). 4. d-Xylose, a sugar not metabolized by the cells, equilibrated with 80% of the amoebal cell water. 5. Cells equilibrated with xylose exhibited countertransport of this sugar against its concentration gradient when another substrate was added to the medium. 6. Blocking of glycolysis by iodoacetate or F(-) has no immediate effect on transport. The presence of a glucose-transport system in E. histolytica contrasts with the situation found in the non-parasitic amoeba, where pinocytosis seems to be the only mechanism of solute uptake.


Collagen biosynthesis. Characterization of subcellular fractions from embyonic chick fibroblasts and the intracellular localization of protocollagen prolyl and protocollagen lysyl hydroxylases. 1. Subcellular fractions of freshly isolated matrix-free embryonic chick tendon and sternal cartilage cells have been characterized by chemical analysis, electron microscopy and the location of specific marker enzymes. These data indicate the fractions to be of a high degree of purity comparable with those obtained from other tissues, e.g. liver and kidney. 2. When homogenates were assayed for protocollagen prolyl hydroxylase and protocollagen lysyl hydroxylase activities, addition of Triton X-100 (0.1%, w/v) was found to stimulate enzyme activities by up to 60% suggesting that the enzymes were probably membrane-bound. 3. Assay of subcellular fractions obtained by differential centrifugation for protocollagen prolyl hydroxylase activity indicated the specific activity to be highest in the microsomal fraction. Similar results were obtained for protocollagen lysyl hydroxylase activity. 4. Submicrosomal fractions obtained by discontinuous sucrose-gradient centrifugation were assayed for the two enzymes and protocollagen prolyl hydroxylase and protocollagen lysyl hydroxylase were found to be associated almost exclusively with the rough endoplasmic reticulum fraction in both tendon and cartilage cells.


Oestradiol uptake and retention, and high-affinity binding sites in cultured rabbit uterus. Oestradiol uptake and turnover was examined in rabbit uterus maintained in organ culture for up to 3 days. Serum decreased the uptake of [(3)H]oestradiol, whereas insulin had no significant effect. During the first 24h of culture unoccupied high-affinity receptors for oestradiol were markedly depleted in the cytosol. Nuclear binding sites remained high during the first day of culture, and were still present after 3 days. The stability of nuclear-bound oestradiol was confirmed by examining the turnover of radioactivity during culture of uteri of rabbits injected with [(3)H]oestradiol 6h before death. Over half of the radioactivity was retained for as long as 3 days in tissue cultured in the absence of oestrogen. In tissue cultured for 24h with unlabelled oestrogen, there was a progressive increase in the displacement of [(3)H]oestradiol as the concentration of unlabelled hormone in the medium was increased from 0.1 to 5nm. Higher concentrations of oestradiol had little additional effect. The oestradiol involved in this displacement reaction was associated with macromolecules, characterized by Sephadex G-25 chromatography and sucrose-density-gradient ultracentrifugation of the 0.4m-KCl extract of the nuclear pellet.


Synthesis of phosphoenolpyruvate carboxykinase (guanosine triphosphate) by isolated liver polyribosomes. 1. Phosphoenolpyruvate carboxykinase (GTP) (EC 4.1.1.32) was synthesized by postmitochondrial supernatants of rat liver in the presence of appropriate salts, an energy supply and [(3)H]leucine. Synthesis of enzyme released from polyribosomes was detected by immunoprecipitation with specific antibody followed by electrophoresis of the dissolved antibody-antigen precipitates on sodium dodecyl sulphate-polyacrylamide gels in the presence of a (14)C-labelled enzyme marker. 2. Enzyme synthesis in vitro occurs predominantly on free rather than bound polyribosomes. 3. Starved animals in which de-induction of phosphoenolpyruvate carboxykinase (GTP) had been initiated by re-feeding for 2h had a markedly decreased rate of enzyme synthesis, whether the measurements were made after injection of radioactive leucine into the intact animal or if synthesis was determined in vitro. 4. The low rate of enzyme synthesis by liver polyribosomes from re-fed animals was not due to the absence of soluble factors, nor could it be increased by the addition of cyclic AMP to the protein synthesis system. 5. Phosphoenolpyruvate carboxykinase (GTP) synthesis in vitro is diminished relative to total protein synthesis when the postmitochondrial supernatant is kept at 0 degrees C for several hours before measurement of protein synthesis. Since this effect is blocked by heparin, it is probably caused by selective ribonuclease attack on enzyme mRNA. 6. De-induction of phosphoenolpyruvate carboxykinase (GTP) is tentatively explained as being due to a transcriptional block in specific mRNA synthesis, followed by rapid degradation of existing message.


Adenosine 3': 5'-cyclic monophosphate in young and senescent human fibroblasts during growth and stationary phase in vitro. Effects of prostaglandine E1 and of adrenaline. Cyclic AMP levels per mg of cell protein were higher in late-passage (senescent) fibroblasts than in early-passage (young) fibroblasts both during growth and stationary phase, but, because the protein concentration per unit volume in senescent cells was lower than in young cells, the molar concentrations of intracellular cyclic AMP were very similar in the two cell types. In both young and senescent fibroblasts cyclic AMP levels declined during growth and no increase in intracellular cyclic AMP occurred in association with density-dependent inhibition of growth. These results indicate that changes in cyclic AMP concentration do not play a role in controlling the growth or in the senescent decline of human fibroblasts. Prostaglandin E(1) (1mum) caused maximal increases in fibroblast cyclic AMP concentration of 60-500-fold after 10-30min, and adrenaline (epinephrine) (10mum) caused maximum increases of 5-25-fold after 2-10min, depending on both the number of passages and the period after subculture. The cyclic AMP level in confluent young cells increased more with prostaglandin E(1) and far less with adrenaline than the cyclic AMP level in confluent senescent cells. During growth to confluence the cyclic AMP response to adrenaline declined in young cells and increased in senescent cells. As these responses to prostaglandin E(1) and to adrenaline changed independently of each other and of the basal cyclic AMP concentration, it is suggested that the expression of hormone receptors is altered both during growth to confluence and during senescence of human fibroblasts.


A study of 3':5'-cyclic mononucleotide-dependent protein kinase from canine prostate glands. 1. An adenosine 3':5'-cyclic monophosphate (cyclic AMP)-dependent protein kinase, located predominantly in the cytosol, was studied in canine prostate. 2. The enzyme exhibited cyclic AMP-binding activity, and could be isolated by chromatography on diethylaminoethyl cellulose. 3. The enzyme was maximally stimulated (fourfold) by 1mum-cyclic AMP, and half-maximal activation of the enzyme was observed in presence of 50nm-cyclic AMP. 4. Equilibrium studies at pH5.0 indicated the presence of one major class of binding site for cyclic AMP, with an association constant of approx. 10(8)m(-1). 5. Stimulation of the enzyme was also observed with the 3':5'-cyclic monophosphate derivatives of cytidine, inosine, guanosine and uridine as well as with dibutyryl cyclic AMP, but higher concentrations of these cyclic nucleotides were required to provide the same degree of activation as that seen with cyclic AMP. 6. Comparing alpha-casein, protamine and different histone subfractions as substrates, highest cyclic AMP stimulation was demonstrated with histones. 7. Although maximum velocity of the enzyme was enhanced approximately fivefold in presence of cyclic AMP, kinetic studies indicated that the apparent K(m) for histone (0.5mg/ml) remained the same whether determined in the presence or absence of the cyclic nucleotide. 8. In addition, cyclic AMP did not significantly change the apparent K(m) for ATP (1.2x10(-5)m). 9. The purified enzyme showed an absolute requirement for bivalent metal ion. Substitution of Mn(2+) for Mg(2+) decreased basal protein kinase activity as well as the stimulation noted with cyclic AMP. Similarly, the basal activity was lowered when Mg(2+) was replaced by Ca(2+) and cyclic AMP produced only little stimulation of the prostatic enzyme.


The effect of adrenocorticotrophin on protein degradation in rat adrenal gland and liver. The rate of adrenal protein degradation appears to be slower in rats to which ACTH (adrenocorticotrophin) has been chronically administered. As measured by the exponential decay of radioactively labelled adrenal protein in vivo, the mean half-lives of total protein and of mitochondrial, microsomal and 18000g-supernatant protein were significantly longer in ACTH-treated animals. Experiments in which either [(3)H]leucine or NaH(14)CO(3) was used to label proteins showed that of the fractions studied, the effect on mitochondrial protein degradation was most pronounced. The half-lives of the same subcellular fractions in rat liver were not affected by ACTH. The possibility that the results might have been caused by changes in radioisotope reutilization and pool size is discussed.


Pullulanase synthesis in klebsiella (aerobacter) aerogenes strains growing in continuous culture. 1. Pullulanase synthesis was studied in 16 classified (N.C.I.B.) strains and in an industrial strain (R) of Klebsiella aerogenes grown in chemostats containing maltose as inducer and sole carbon source. 2. Maximum synthesis was associated with carbon-limited growth at a low dilution rate (about 0.2h(-1)). The enzyme remained firmly cell-bound and seemed to be located on the cell surface. 3. Three strains had high activity (R, N.C.I.B. 5938, 8017), twelve were intermediate, and two (N.C.I.B. 8153, 9146) had negligible activity but were inducible with pullulan. 4. Pullulan similarly induced low, but adequate, activity in the other strains in conditions (nutrient limitation other than carbon-limitation) in which pullulanase was otherwise very seriously repressed. Nevertheless, in carbon limitation pullulan induced no more enzyme than did maltose, maltotriose or oligosaccharide mixtures, and ;hyperactivity' never developed on protracted culture. 5. Cyclic AMP relieved the transient repression produced by adding glucose to maltose-limited cultures and a further change to glucose-limited conditions led to constitutive pullulanase synthesis. 6. Amylomaltase and alpha-glucosidase activities were also examined but in less detail. 7. The presence of pullulanase in maltose-limited growth is discussed, but no clear function can be assigned to it at present. The molar growth yields for all the strains were very similar, and no correlation was found between the overgrowth of one strain by another and pullulanase activity. Further, any function as a general branching enzyme in polysaccharide synthesis seems unlikely.


Role of steroid synthesis in the process of ovulation.


Binding of gonadotropins to ovarian cells.


Triglyceride lipase activity in rhesus monkey spermatozoa.


Alpha-chlorohydrin-induced changes in the distribution of free myo-inositol and prostaglandin F2alpha, and synthesis of phosphatidylinositol in the rat epididymis.


Electron microscopic cytochemical study of phosphatases during spermiogenesis in Chinese hamster.


Abnormality of the structure and composition of plasma lipoproteins (HDL) during different types of hepatitis.


Vascular reactivity to angiotensin in borderline hypertension.


The effect of colymycin M, gentamycin and kanamycin on depression of neuromuscular transmission induced by pancuronium bromide.


Pattern of intrafamilial transmission of smallpox in Calcutta, India. The pattern of intrafamilial transmission of smallpox in Calcutta was studied in 43 index cases, 3 of which were haemorrhagic, 14 confluent, and 26 discrete. They had 741 contacts. The attack rate in vaccinated contacts was significantly less than in unvaccinated contacts, but there was no such difference in the case rates caused by severe and mild index cases. Females had higher attack rates than males, the difference being more marked among the vaccinated. The vaccination status of the index cases seemed to affect their secondary case rates. The incidence of secondary cases among contacts living in the same room as a patient and in other rooms in the same compound was practically equal.


Seleno methionine-75 as a scanning agent for neuroblastoma.


Lack of adaptation of ACTH secretion to sequential ether, tourniquet, or leg-break stress.


Evidence for homology between ovine and human placental lactogens.


Behaviour of Wilms tumour and normal metanephros in organ culture.


Long-term in vitro culture of pathogenic Gross leukemia virus in mouse thymus cells.


Properties of the mouse cells transformed with DNA containing the murine sarcoma provirus.


Immunization against Gross malignant lymphoma with mouse cell lines chronically infected with non-oncogenic murine C-type viruses.


The entry of antifertility and other compounds into the testis.


Idle thoughts of idle pharmacologists.

Idle thoughts of idle pharmacologists.


Feedback regulation of gonadotrophins in the male.


Cyclic changes in uterine venous and peripheral plasma levels of F prostaglandins correlated with peripheral progesterone levels in the golden hamster.


Prostaglandins and myometrial contractility.


Studies on the purification of normal immunoglobulin for intravenous use.


Antibody spectrum in human immunoglobulin preparation in Japan.


Changes with age in pituitary-adrenal responsiveness and reactivity to mild stress in mice.


Gestational trophoblastic neoplasms.

Gestational trophoblastic neoplasms. A review of the classification, biological behavior, clinical diagnosis, and treatment of gestational trophoblastic neoplasms is presented. The events which followed the utilization of chemotherapy as a successful means of therapy are included. Especially important has been the recent recognition that high risk patients, i.e., patients with HCG titers greater than 100,000 IU/24 hr, duration of symptoms greater than four months, and metastasis to the brain and/or liver, with metastatic trophoblastic disease can be managed successfully if treated initially with combination chemotherapy and adjuvant measures including radiation and infusional therapy. Detectable levels of human chorionic gonadotropin are necessary for diagnosis and management of patients with this disease. The lack of sensitivity of commercially available pregnancy tests and the recent ability to determine HCG by means of an antigenically different beta-subunit are discussed.


Chemotherapy of advanced ovarian  carcinoma: a prospective randomized comparison of phenylalanine mustard and high dose cyclophosphamide. Twenty-four fully staged, previously untreated patients with advanced ovarian carcinoma were prospectively randomized to either intensive intravenous cyclophosphamide or conventional oral Melphalan therapy. The median durations of initial remissions (5 and 6 mo) and the median durations of survival (15 and 14 mo) were similar for the two regimens but the toxicity of the intensive regimen was excessive. Followup indicates that long term disease free survivals are possible in those patients who achieve complete remissions on chemotherapy alone as three of the four patients achieving complete remission in the present study remain free of disease with a median survival in excess of 30 mo. High dose intensive alkylating agent therapy in the manner used in the present study fails to enhance the response to chemotherapy and produces unacceptable toxicity.


Fetal lung maturation. I. Phosphatidic acid phosphohydrolase in rabbit lung.


Observations on the type of infection by Epstein-Barr virus in peripheral lymphoid cells of patients with infectious mononucleosis. Transformation to continuous cell lines has been studied in cultures of peripheral leuckocytes from infectious mononucleosis (IM) patients and in co-cultures of IM leukocytes and foetal cord blood leukocytes of opposite sex. The transformed cells in the co-cultures were of mixed origin with foetal cells usually predominating. Neutralizing antisera to EB virus markedly reduced or abolished the incidence of transformation in IM leukocyte cultures. This effect was not due to cytotoxicity and followed the pattern seen with cultures where transformation was known to depend on the inter-cellular transfer of infectious EB virus. The findings suggest that EB virus is harboured in peripheral lymphocytes of IM patients as a non-productive unexpressed infection which is activated to produce virus in vitro, the particles released then infecting neighbouring cells to give transformed lines. The differences between this mechanism and the one whereby lines arise in culture from malignant cells of Burkitt's lymphoma are considered, and their significance is discussed.


Cytogenetic studies on human lymphoblastoid cell lines from Burkitt's lymphomas and other sources. The occurrence and incidence of a characteristic banding abnormality in a No. 14 chromosome has been studied in Burkitt-lymphoma-derived and certain other EB virus-associated lymphoblastoid cell lines. The abnormality was readily detected in 7 out of 7 Burkitt lines, and when present could be seen in 100% of cells with recognizable No. 14 chromosomes. In contrast, the abnormality was not observed in 775 cells from 31 infectious mononucleosis-derived lines nor in 450 cells from 18 lines obtained from cord blood lymphocytes experimentally transformed by EB virus in vitro. The significance of the abnormality as an indication of cells transformed by the virus in vivo is discussed, and the importance of this considered in relation to a possible oncogenic role for EB virus in man.


Increased polyamine concentrations in the cerebrospinal fluid of patients with brain tumors. An automated method for the quantitative analysis of the polyamines putrescine, spermidine and spermine in cerebrospinal fluid (CSF) was used to analyze CSF samples from 37 patients with central nervous system (CNS) tumors and from 13 patients without tumors. The putrescine and spermidine concentrations in the CSF of most patients in tumors, particularly those with glioblastomas or medulloblastomas, were elevated when compared with those of non-tumor-bearing patients.


The effects of cyclophosphamide on in vitro correlates of tumor immunity. The effects of cyclophosphamide (CY) on tumor immunity against isografts of rat sarcomas induced by polyoma virus were studied using in vitro techniques. Groups of sarcoma-bearing animals received CY (250 mg/kg intraperitoneally 11 days after isografting) CY (150 mg/kg IP 8 days after isografting), or IP injections of 0.9% NaCl. In control rats tumor growth was progressive. All CY-treated animals showed transient tumor regression of at least 50% of their pretreatment tumor volume. Despite a drastic depression in numbers of blood leukocytes as well as lymph-node cells following CY treatment, animals treated with 150 mg/kg CY were shown to have blood lymphocyte and lymph-node cell cytotoxicity in vitro against plated sarcoma target cells comparable to untreated sarcoma-bearing animals. Sera obtained from sracoma-bearing rats prior to CY treatment specifically blocked lymphocyte cytotoxicity against sarcoma target cells. After CY treatment serum blocking activity could not be demonstrated during the period of tumor regression, but reappeared in parallel with tumor regrowth. Antibodies cytotoxic to sarcoma target cells when homologous complement was added could not be demonstrated in sera obtained from animals before CY treatment, but were present after treatment during tumor remission. Following CY treatment, sera obtained from treated animals, when mixed with blocking sera from control animals, could counteract or unblock the blocking activity of tumor-bearer sera. Unblocking capacity was present only in sera obtained during CY-induced tumor remission. Serum IgG concentration was significantly and temporarily decreased after CY treatment.


Evaluation of Epstein-Barr virus-associated nuclear antigen with various human cell lines. Critical evaluation of the anti-complement immunofluorescence (ACIF) test for Epstein-Barr virus-associated nuclear antigen (EBNA) in known EBV-associated cell lines was carried out. The ACIF procedure, in which the cell smears were thoroughly air-dried and fixed with carbon tetrachloride (for 15 min at room termperature), provided reproducible staining results with minimum variations. The fixed smears coulb be stored for at least 5 weeks at minus 80 degrees C without loss of reactivity. On the basis of the above evaluation, a total of 59 human cell lines, which had unknown or uncertain association with EBV, were examined for the presence or absence of EBNA by the ACIF procedure. All of the cell lines tested could be judged positive or negative for EBNA. All of 21 lines growing as monolayer or in a mixed state of monolayer and suspension, were negative. Of 38 lines grown in suspension, 36 lymphoblastoid lines were positive but the remaining 2 lines (seemingly not lymphoblastoid) were negative.


Chromosome analysis and agglutination by concanavalin a of primary simian-virus-40-induced tumors. Tumors induced by SV40 virus in newborn and adult Syrian hamsters were analyzed for their growth properties in vitro, transplantation, agglutination with concanavalin A and chromosome constitution. Following transfer to culture flasks tumor cells grew for 2-3 weeks, then went through a "degenerative phase". Eventually lines were established which became adapted to in vitro culture conditions. Agglutination properties of these tumor cells were similar to those of cells transformed in vitro with SV40 virus. Of five subcutaneous and six intratesticular tumors that were analyzed for their chromosome constitution, all had a hypotetraploid chromosome number distribution. The results of the chromosome studies suggest a similiar pattern in the evolution of malignant properties of cells transformed in vitro and in vivo following infection with SV40 virus.


Genetic control of the regulation of cell susceptibility to carcinogenic polycyclic hydrocarbons by cyclic AMP. The metabolism of benzo (a) pyrene (BP) in normal golden hamster and BHK cells in culture was increased by treating the cells with dibutyryl cyclic AMP (dcAMP), prostaglandin E1, theophylline or aminophylline. The largest increase, 6-fold for the normal cells and 20-fold for the BHK cells, was obtained by treatment with both dcAMP and aminophylline. Treatment with aminophylline also stimulated the metabolism of 20-methylcholanthrene and 7,12-dimethylbenz (a) anthracene. The increased metabolism of these three carcinogeneic polycyclic hydrocarbons was associated with an increased cytotoxicity. Treatment with aminophylline increased the cytotoxicity of five other potent and weak carcinogenic polycyclic hydrocarbons, but not of two non-carcinogenic polycyclic hydrocarbons. The amount of BP metabolism in 27 different cell types from various mammals, including humans, ranged from less than 0.1 mug to 2.3 mug metabolized BP per 10-6 cells. Treatment of these different cell types with aminophylline gave either an increase in BP metabolism, an induction of metabolism in cells that did not metabolize without aminophylline, or no induction after treatment with aminophylline and dcAMP. The existence of responding and non-responding cell lines indicates that the regulation of the level of polycyclic hydrocarbon metabolism by dcAMP is genetically controlled. The induction of metabolism in cells that did not metabolize without aminophylline resulted in the conversion of cell resistance to cell susceptibility to the cytotoxic effect of BP. Treatment with dcAMP and aminophylline can therefore be used to increase the sensitivity of screening tests for chemical carcinogens.


The role of nitrosamines in the causation of primary carcinoma.


Leukocyte adherence inhibition as measured by a radioisotopic technique for detection of cell-mediated tumor immunity. It has been previously reported that cell-mediated tumor immunity may be detected by leukocyte adherence inhibition (LAI) as determined by a visual counting technique in the presence of soluble tumor antigen. In the present experiments leukocyte adherence was measured by a radioisotopic technique. Peripheral blood mononuclear cells from Wistar/Fu rats and lymph-node cells (LNC) from C3H/J mice were labelled with Technetium 99m (99mTc) and incubated with medium alone and with medium containing tumor antigens (high dilutions of dialyzed tumor homogenates) in the wells of plastic tissue-culture plates. After incubation, fluid and non-adherent cells were removed. The ratio of residual radioactivity in wells with antigen to that in wells without antigen was determined. Adherence of blood mononuclear cells from rats bearing syngeneic transplants of a polyoma-virus-induced tumor was inhibited by dialyzed homogenates of this tumor. Adherence of blood mononuclear cells from normal rats was not inhibited. Adherence of LNC from mice bearing syngeneic transplants of a 3-methylcholanthrene (3-MCA)-induced fibrosarcoma was inhibited by dialyzed homogenates of this tumor. Adherence of LNC from normal mice or from mice or from mice bearing a different 3-MCA-induced tumor was not inhibited. These results support the use of LAI as a simple test for cell-mediated tumor immunity. Measuring relative leukocyte adherence with the radioisotope 99mTc eliminates possible bias in counting and permits multiple replicate determinations with a small number of leukocytes.


Neuraminidase-mediated augmentation of in vitro immune response of patients with solid tumors. Host blood lymphocytes undergo accentuated blastic transformation when cultured with tumor cells pretreated with neuraminidase. The effect has been observed in 38 patients with such common solid tumors as bronchus carcinoma, skin melanoma, hypernephroma, or adenocarcinoma of the breast, lung, colon, or rectum. Individual response varied but often exceeded response to allogeneic cells. Three patients with glioblastoma of the brain did not respond. Lymphoblastic transformation was not observed in three of four cultures containing benign tumor or in any cultures containing normal tissue analogues of the malignant tumors. A factor in host blood serum inhibiting lymphoblastic transformation correlated to abnormal elevation of serum-bound sialic acid. This blocking factor differed in specificity from enhancing antibody or serum blocking complexes described by other investigators. Blocking effects were observed when the tumor-cell type of a serum donor differed from the cell type of the culture test tumor. Serum with abnormal elevation of bound sialate from a cancerfree human also non-specifically blocked host response to tumor. The blocking effect could be eliminated by partial enzymatic removal of bound sialic acid from serum glycoproteins.


Studies on nasopharyngeal carcinoma in Thailand.


Serologic survey for certain childhood viral infections in Rangoon in 1971.


Role of thiamine metabolism in the central nervous system. I. Basic properties of thiamine triphosphatase in rat brain. The properties of soluble and microsomal thiamine triphosphatase (TTPase) in rat brain were examined. The subcellular distributions and the pH optima of these enzyme activities differ markedly. TTPase seems to be distinct from a general nucleoside triphosphatase. The TTPase activities have an absolute divalent cation requirement which is fulfilled by Mg-++ or Ca-++ in microsomes and by Mg-++, but not Ca-++, in the soluble fraction. Addition of a physiological concentration of Ca-++ markedly inhibited the soluble TTPase activity.


Role of thiamine metabolism in the central nervous system. II. Effects of various agents on thiamine triphosphatase activity in rat brain. The effects of various agents on the activity of brain thiamine triphosphatase (TTPase) in vivo and in vitro were studied. Thiamine deficiency caused a significant increase in soluble TTPase activity and a decrease in membrane-associated TTPase activity. Insulin and a fasting state did not affect these enzyme activities. DL-Methamphetamine (10mg/kg i.p.) increased the activity of the soluble TTPase, whereas reserpine (2.5 mg/kg i.p.) caused no change in the enzyme activities. A single injection of chlopromazine (25 mg/kg s.c.) had no effect on the microsomal or soluble TTPase activities, but repeated injections reduced the activity of the microsomal enzyme. The effects of various neuroactive agents on microsomal TTPase activity were examined in vitro. Among the drugs tested, only chlorpromazine caused marked inhibition of the enzyme activity.


Effect of dibutyryl adenosine 3',5'-monophosphate on catecholamine synthesis in rat brain cortical slices and isolated vasa deferentia.


Inhibitory effect produced by stimulation of afferent nerves on responses of cat dorsolateral fasciculus fibres to nocuous stimulus.


Cytomegalovirus infections in human renal transplants.


Cyclic nucleotide regulation of gastric acid secretion.


Recovery from hepatorenal syndrome after successful orthotopic liver transplantation.


Cyclic GMP in stimulated gastric mucosa.


Influence of loxapine on the sleep-wakefulness cycle of the rat.


Mechanism of impaired diuresis in dog with liver disease secondary to bile duct obstruction.


Behavioral effects of norepinephrine and dibutyryl 3',5'AMP in centrally sympathectomized rats.


Evidence for presence of a virus in glioblastoma multiforme cells.


Collagen synthesis in keloid and hypertrophic scar following intralesional use of triamcinolone.


Effects of clofibrate and anovulatory drugs on biliary lipid composition and bile acid kinetics.


Testicular torsion: an experimental study.


Radioimmunoassay of the beta-subunit of human chorionic gonadotropin, monitor of chemotherapy in gestational trophoblastic neoplasm.


Action of psychotropic drugs upon pO2 in the lateral amygdala and pontine reticular formation during the sleep-wakefulness cycle.


Hypocalcemic, calcitonin-like factor from a Zollinger-Ellison tumor.


Phosphodiesterase inhibitors and cerebral vasospasm.


The anatomical substratum of pain: evidence derived from morphometric studies on peripheral nerve.


Persistence of encephalitogenic arbovirus in brain cell cultures.


An outbreak of a previously undescribed toxic polyneuropathy due to industrial solvent.


Acrylamide neuropathy: selective vulnerability of sensory fibers.


Biologic behavior of canine mammary neoplasms based on a histogenetic classification.


The relationship between hepatitis-associated antigen and the development of hepatocellular cancer.


Functional control of the biliary tract.


Adipose tissue and endotoxin shock.

Adipose tissue and endotoxin shock.


The pre-beta lipoprotein phenomenon in relation to serum cholesterol and triglyceride levels, the Lp(a) lipoprotein and coronary heart disease.


Prostaglandin antagonists.

Prostaglandin antagonists.


Hypothalamic amines and the release of gonadotrophins and other anterior pituitary hormones.


Action of imidazole and some of its derivatives on nerve-muscle transmission in frog.


Chemotaxis: Impressions and problems.

Chemotaxis: Impressions and problems.


Mechanism of movement and maintenance of polarity in leucocytes.


The chemotactic effect of cyclic AMP and its analogues in the Acrasieae.


Influence of incisor tooth development on osteoclast abundance and generation in the foetal rat mandible.


The lactate dehydrogenase--reduced nicotinamide--adenine dinucleotide--pyruvate complex. Kinetics of pyruvate binding and quenching of coeznyme fluorescence. The stopped-flow kinetic studies described in this and the following paper (Südi, 1974) demonstrate that a Haldane-type description of the reversible lactate dehydrogenase reaction presents an experimentally feasible task. Combined results of these two papers yield numerical values for the six rate constants defined by the following equilibrium scheme, where E represents lactate dehydrogenase: [Formula: see text] The experiments were carried out at pH8.4 at a relatively low temperature (6.3 degrees C) with the pig heart enzyme. Identification of the above two intermediates and determination of the corresponding rate constants actually involve four series of independent observations in these studies, since (a) the reaction can be followed in both directions, and (b) both the u.v. absorption and the fluorescence of the coenzymes are altered in the reaction, and it is shown that these two spectral changes do not occur simultaneously. Kinetic observations made in the reverse direction are reported in this paper. It is demonstrated that the fluorescence of NADH can no longer be observed in the ternary complex E(NADH) (Pyr). Even though the oxidation-reduction reaction rapidly follows the formation of this complex, the numerical values of k(-4) (8.33x10(5)m(-1).s(-1)) and k(+4) (222s(-1)) are easily obtained from a directly observed second-order reaction step in which fluorescent but not u.v.-absorbing material is disappearing. U.v.-absorption measurements do not clearly resolve the subsequent oxidation-reduction step from the dissociation of lactate. It is shown that this must be due partly to the instrumental dead time, and partly to a low transient concentration of E(NAD+) (Lac) in the two-step sequential reaction in which the detectable disappearance of u.v.-absorbing material takes place. It is estimated that about one-tenth of the total change in u.v. absorption is due to a ;burst reaction' in which E(NAD+) (Lac) is produced, and this estimation yields, from k(obs.)=120s(-1), k(-2)=1200s(-1).


Macroscopic rate constants involved in the formation and interconversion of the two central enzyme--substrate complexes of the lactate dehydrogenase turnover. The preceding paper (Südi, 1974) reports partial success in describing the conversion of E(NADH) plus pyruvate into E(NAD+) plus lactate in terms of a simple Haldane-type scheme which involves two intermediates (E(NADH) (Pyr) and E(NAD+) (Lac)), where E represents lactate dehydrogenase. This information is completed here by reporting kinetic results obtained by carrying out the same reaction in the opposite direction. The combined results of these two papers confirm the findings of Holbrook & Gutfreund (1973) that the observed spectral changes do take place at the level of resolution of this simple two-intermediate scheme. The following numerical values for the rate (and equilibrium) constants involved in their formation and decomposition are reported: [Formula: see text] It is shown that although the precision of estimation of some of these numerical values is subject to some experimental uncertainty, their derivation from direct experimental observations only involves the principle of microscopic reversibility. This paper describes stopped-flow kinetic observations made with E(NAD+) and lactate as the two reactants. It is shown that fluorescence and u.v.-absorption measurements yield the same experimental rate constant for the last reaction step in which E(NADH) is generated. On the other hand, the generation of E(NADH) (Pyr) can only be indirectly observed, as a less than stoicheiometric ;burst', and by u.v.-absorption measurements only. It is shown that the stoicheiometry of this partial ;burst reaction', and a pre-equilibrium factor in the directly observed rate of E(NADH)-production, yield equivalent information about the reversible oxidation-reduction step. It is further shown that the pre-equilibrium factor that is involved in the generation of E(NADH) can be determined because k(+4)=222s(-1) is already known (Südi, 1974). Since the fluorescence measurements yield much more precise estimations, and their interpretation is considered by the author to be free of ambiguity, the presented quantitative analysis is based on the fluorescence observations.


The reaction of Pseudomonas aeurginosa cytochrome c oxidase with sodium metabisulphite. Spectrophotometric evidence is presented for the formation of a complex between metabisulphite and reduced Pseudomonas aeruginosa cytochrome c oxidase. The effects of metabisulphite on the recombination of CO with the reduced enzyme are discussed in terms of alternate binding sites for S(2)O(5) (2-) and CO.


Comparative enzymology of the adenosine triphosphate sulphurylases from leaf tissue of selenium-accumulator and non-accumulator plants. 1. ATP sulphurylases were partially purified (20-40-fold) from leaf tissue of Astragalus bisulcatus, Astragalus racemosus (selenium-accumulator species) and Astragalus hamosus and Astragalus sinicus (non-accumulator species). Activity was measured by sulphate-dependent PP(i)-ATP exchange. The enzymes were separated from pyrophosphatase and adenosine triphosphatase activities. The properties of the Astragalus ATP sulphurylases were similar to the spinach enzyme. 2. The ATP sulphurylases from both selenium-accumulator and non-accumulator species catalysed selenate-dependent PP(i)-ATP exchange; selenate competed with sulphate. The ratio of V(selenate)/V(sulphate) and K(m)(selenate)/K(m)(sulphate) was approximately the same for the enzyme from each species. 3. Sulphate-dependent PP(i)-ATP exchange was inhibited by ADP, chlorate and nitrate. The kinetics of the inhibition for each enzyme were consistent with an ordered reaction mechanism, in which ATP is the first substrate to react with the enzyme and PP(i) is the first product released. 4. Synthesis of adenosine 5'-[(35)S]sulphatophosphate from [(35)S]sulphate was demonstrated by coupling the Astragalus ATP sulphurylases with Mg(2+)-dependent pyrophosphatase; the reaction was inhibited by selenate. An analogous reaction using [(75)Se]selenate as substrate could not be demonstrated.


Reduction and inactivation of superoxide dismutase by hydrogen peroxide. Reactions of H(2)O(2) with superoxide dismutase were studied by e.p.r. (electron paramagnetic resonance) spectroscopy and other methods. In agreement with earlier work, the Cu(2+) of the enzyme is reduced by H(2)O(2), although the reaction does not go to completion and its kinetics are not simple. With dilute enzyme the time for half-reduction with 9mm-H(2)O(2) is about 150ms. It is suggested that the reaction is a one-electron reduction, involving liberation of O(2) (-). On somewhat more prolonged exposure to H(2)O(2), the enzyme is inactivated. For enzyme in dilute solution and over a limited range of H(2)O(2) concentrations, inactivation is first-order with respect to enzyme and reagent, with k=3.1m(-1).s(-1) at 20-25 degrees C. Inactivation is accompanied by marked changes in the e.p.r. and visible spectra and appears to be associated with destruction of one histidine residue per subunit. It is suggested that this histidine is close to the metal in the native enzyme and essential for its enzymic activity.


Mechanism of action of superoxide dismutase from pulse radiolysis and electron paramagnetic resonance. Evidence that only half the active sites function in catalysis. 1. Detailed studies on the mechanism of the enzymic reaction of bovine superoxide dismutase were carried out by using pulse radiolysis and electron paramagnetic resonance (e.p.r.). 2. The second-order rate constant for reaction between superoxide dismutase and the superoxide ion was redetermined as (2.37+/-0.18)x10(9)m(-1).s(-1) at 25 degrees C. This reaction governs the turnover, and any first-order steps must have rate constants higher than about 10(6)s(-1). Turnover has a low activation energy and is slowed substantially when the viscosity is increased with glycerol, confirming that the reaction rate is near the limit for diffusion control. In water a reversible conformation change to a less active form appears to take place above about 40 degrees C. 3. Pre-steady-state rates of reduction and reoxidation of copper in the enzyme are consistent with these processes being rate-limiting in enzyme turnover. 4. Examination, with the help of computer simulation, of the e.p.r. spectra at 9 and 35GHz of native superoxide dismutase indicated that, apart from 10-20% of impurities, only one species of Cu(2+) is distinguishable. Further, the specific activity of our enzyme preparations, measured by pulse radiolysis, is at least as high as that obtained by other workers. 5. Nevertheless, measurement of the proportion of copper present as Cu(2+) (determined both optically and by e.p.r. spectroscopy) in the steady states approached from both the oxidized and the reduced forms of the enzyme, indicates (after allowing for the impurities) that only half of the copper atoms participate in turnover. E.p.r. spectroscopy provided no evidence for differences between functioning and non-functioning Cu(2+) atoms. 6. It is suggested that the results may be best interpreted in terms of an allosteric type of mechanism, with two initially indistinguishable copper atoms in the enzyme. Reaction of one of these with a superoxide ion then renders the other, at least transiently, unreactive.


The binding of oxidized and reduced nicotinamide--adenine dinucleotides to bovine liver uridine diphosphate glucose dehydrogenase. The binding of NAD(+) and NADH to bovine liver UDP-glucose dehydrogenase was studied by using gel-filtration and fluorescence-titration methods. The enzyme bound 0.5mol of NAD(+) and 2 mol of NADH/mol of subunit at saturating concentrations of both substrate and product. The dissociation constant for NADH was 4.3mum. The binding of NAD(+) to the enzyme resulted in a small quench of protein fluorescence whereas the binding of NADH resulted in a much larger (60-70%) quench of protein fluorescence. The binding of NADH to the enzyme was pH-dependent. At pH8.1 a biphasic profile was obtained on titrating the enzyme with NADH, whereas at pH8.8 the titration profile was hyperbolic. UDP-xylose, and to a lesser extent UDP-glucuronic acid, lowered the apparent affinity of the enzyme for NADH.


Characterization of plasma lipoproteins separated and purified by agarose-column chromatography. 1. A simple method for isolation of individual human plasma lipoprotein classes is presented. In this technique, lipoproteins are removed from plasma at d1.225 by ultracentrifugation, after which they are separated and purified by agarose-column chromatography. 2. Three major classes are obtained after agarose-column chromatography. Separation between classes is excellent; more than 95% of the lipoproteins eluted from the column are recovered in the form of a purified lipoprotein class. 3. Each lipoprotein class was characterized immunologically, chemically, electrophoretically and by electron microscopy. A comparison of the properties of the column-isolated lipoproteins was made with very-low-density lipoproteins, low-density lipoproteins, and high-density lipoproteins separated by sequential ultracentrifugation at densities of 1.006, 1.063 and 1.21 respectively. 4. By each criterion, peak-I lipoproteins from the agarose column are the same as very-low-density lipoproteins, peak-II lipoproteins are the same as low-density lipoproteins, and peak-III lipoproteins are the same as high-density lipoproteins. Thus the lipoprotein classes isolated by both methods are similar if not identical. 5. The agarose-column separation technique offers the advantage of a two- to three-fold saving in time. In addition, the column-elution pattern serves as a recording of the size distribution of lipoproteins in plasma. 6. The most complete characterization is reported for human plasma lipoproteins. The results with rhesus-monkey and rabbit lipoproteins were identical.


Phosphonomethyl analogues of phosphate ester glycolytic intermediates. Analogues of dihydroxyacetone phosphate and of 3-phosphoglycerate were made in which the phosphate group, -O-PO(3)H(2), is replaced by the phosphonomethyl group, -CH(2)-PO(3)H(2). The analogue of dihydroxyacetone phosphate is a substrate for aldolase and glycerol 1-phosphate dehydrogenase (Stribling, 1974), but not for triose phosphate isomerase. The analogue of 3-phosphoglycerate oxidizes NADH under the combined action of 3-phosphoglycerate kinase and glyceraldehyde 3-phosphate dehydrogenase if ATP is added. Thus four out of the five glycolytic enzymes tested handle the phosphonomethyl compounds like the natural phosphates.


Properties of the phosphonomethyl isosteres of two phosphate ester glycolytic intermediates. The enzymic synthesis of the 1-phosphonomethyl isostere of fructose 1,6-diphosphate in which the 1-phosphate (-OPO(3)H(2)) is replaced by the phosphonomethyl group (-CH(2)PO(3)H(2)) is described. The kinetic properties of this fructose diphosphate isostere and of 4-hydroxy-3-oxobutylphosphonic acid, an isostere of dihydroxyacetone phosphate, with aldolase (EC 4.1.2.13), fructose diphosphatase (EC 3.1.3.11) and glycerol phosphate dehydrogenase (EC 1.1.1.8) are described (see Table 1).


Phosphorylation of troponin and the effects of interactions between the components of the complex. 1. The troponin complex from skeletal muscle contains approximately 1 mol of phosphate/80000g of complex, covalently bound to the troponin T component. 2. On prolonged incubation of the troponin complex or troponin T with phosphorylase kinase the phosphate content of troponin T was increased to approx. 3mol/mol. 3. On prolonged incubation of troponin I with phosphorylase kinase up to 1.6mol of phosphate/mol were incorporated. 4. Phosphorylation of troponin I was greatly inhibited by troponin C owing to the strong interaction between these proteins. Thus in the troponin complex troponin T was the main substrate for phosphorylase kinase. The phosphorylation of isolated troponin T was also inhibited by troponin C. 5. Troponin I was phosphorylated when the troponin complex was incubated with a bovine cardiac 3':5'-cyclic AMP-dependent protein kinase. Troponin T either in its isolated form or in the troponin complex was not phosphorylated by bovine protein kinase to any significant extent under the conditions used. 6. If the troponin complex was dephosphorylated to 0.2mol/mol, or phosphorylated up to 2.5mol/mol there was no significant effect on the ability of normal concentrations to confer Ca(2+) sensitivity on the adenosine triphosphatase of densensitized actomyosin.


Affinity chromatography of nicotinamide nucleotide-dependent dehydrogenases on immobilized nucleotide derivatives. A series of chemically-defined adenosine phosphate ligands attached to Sepharose 4B were used as active-site probes in studying the interaction of enzymes with their coenzymes and substrates and to test the suitability of these matrices for ;general ligand' affinity chromatography. Nicotinamide nucleotide-dependent dehydrogenases were used as models to test this methodology. Elution from these columns by NAD(+) and/or AMP gradients (in the presence or the absence of substrates and/or nicotinamide mononucleotide) was consistent with: (1) the compulsory ordered addition of substrates to lactate and malate dehydrogenase; (2) the necessity for the NMN moiety of NAD(+) to bind to these enzymes before the substrate; and illustrated: (3) that the binding of these two hydrogenases to these columns compared very well with the published three-dimensional models for these enzymes and (4) that separation of mixtures of dehydrogenases depended on the choice of matrix and displacing ion and whether any additions (e.g. substrates) were made to the gradients used. These techniques were used to purify UDP-glucose dehydrogenase from a crude starting material on a phosphate-linked UDP (or ADP) matrix. The binding of this enzyme to these two columns was not consistent with either an ordered or random addition of substrates and suggested a more complex mechanism.


Kinetic studies of bovine liver carbamoyl phosphate synthetase. A through study of initial-rate data has been made on carbamoyl phosphate synthetase from bovine liver. On the basis of the results the order of substrate binding to the enzyme is ATPMg followed by HCO(3) (-), ATPMg and NH(4) (+). A model for the enzymic mechanism is proposed, and the rate equations describing it are presented. Details of the derivation of the initial-rate equation for the kinetic mechanism proposed have been deposited as Supplementary Publication SUP 50032 (6 pages) at the British Library, Lending Division (formerly the National Lending Library for Science and Technology), Boston Spa, Yorks. LS23 7QB, U.K., from whom copies may be obtained on the terms indicated in Biochem. J. (1973), 131, 5.


Product inhibition studies on bovine liver carbamoyl phosphate synthetase. A study of the product-inhibition patterns of carbamoyl phosphate synthetase from bovine liver is reported. Inhibition by adenosine, AMP and inorganic ions is also reported. The results are in agreement with the previously proposed model in which the order of substrate binding is ATPMg, followed by HCO(3) (-), ATPMg and NH(4) (+). The order of product release on the basis of the reported results is carbamoyl phosphate, followed by ADPMg, ADPMg and inorganic phosphate.


Hydrolysis of bradykinin and its higher homologues by angiotensin-converting enzyme. The hydrolysis of bradykinin and its higher homologues by angiotensin-converting enzyme has been investigated by using an automated ninhydrin technique. The results show an inverse relationship of hydrolysis rate with size and charge of the peptide, which parallels the inactivation in the pulmonary circulation and offers an explanation for the selectivity of metabolism of these kinins by the lungs.


Study of the experimental infection of pigs with bovine viral diarrhea (BVD) virus.


A serologic survey in cattle to bovid herpesvirus 2.


A non-chromatographic radioimmunoassay for plasma dexamethasone.


Specific binding of 125I-labeled human follicle stimulating hormone to testicular slice.


Treatment of idiopathic pituitary dwarfism with human growth hormone (KABI).


Thyroid function and polyamines. I. Rapid fluctuation of thyroid ornithine decarboxylase activity in response to change in circulating thyrotropin level in the rat.


Evaluation of myocardial revascularization utilizing Tc-99m pyrophosphate. Early clinical application of technetium 99m labeled pyrophosphate for cardiac imaging has revealed a safe noninvasive method of determining areas of impaired myocardial perfusion in patients with atherosclerotic occlusive coronary artery disease. Using this method, we were able to demonstrate improvement in myocardial blood supply following coronary artery bypass surgery.


Clinical evaluation of cinnarizine in hyperlipaemic patients.


Immunofluorescent staining of placental alkaline phosphatase in gastric and rectal carcinoma.


Transfer-RNA methylase activity in rat ascites hepatomas: Altered methylation patterns in the presence of guanidine carbonate.


Protein-bound polysaccharide preparation, PS-K, effective against mouse sarcoma-180 and rat ascites hepatoma AH-13 by oral use.


[Depressed lymphocyte response in mixed-wife-husband leucocyte cultures in normal and pathological pregnancies; effect of heat-inactivated serum].


Antiviral effect of some indigenous plant extracts on vaccinia & fowl-pox viruses in chick embryo fibroblast cell culture.


Studies on the geographic distribution of the human serum beta-lipoprotein antigen Ag(x).


Antimicrobial properties of some organometallic diethyldithiocarbamates.


From the symbolic stimulus to the pathophysiologic response: immune mechanisms.


Cytoplasmic synthesis of viral DNA early during infection and cell transformation by the murine sarcoma-leukemia virus.


Immune complexes associated with neoplasia: presence of Epstein-Barr virus antigen-antibody complexes in Burkitt's lymphoma.


Growth characteristics of acute hemorrhagic conjunctivitis (AHC) virus in monkey kidney cells. I. Effect of temperature on viral growth.


Picornaviridae.

Picornaviridae.


Precipitating antibodies to herpes simplex virus in human sera: prevalence of antibody to common antigen (band II).


Pathogenesis and pathology of infection with two strains of avian adenovirus.


High-pressure liquid chromatography with ion-exchange celluloses and its application to the separation of estrogen glucuronides.


Pathogenicity of avian adenoviruses for day-old chicks.


Relation of enterotoxigenic Clostridium perfringens type A to food poisoning. II. Acid exposure and storage conditions affecting enterotoxigenesis of C. perfringens.


Serum inhibition of gingival collagenase. Collagenases derived from bovine and human gingiva are inhibited effectively by serum. In bovine and human serum fractionated by gel chromatography, alpha2-macroglobulin is the only significant inhibitor of gingival collagenase. alpha11-Antitrypsin inhibited collagenase only in very high concentration and was several hundred-fold less effective than alpha2-macroglobulin. Inhibition of gingival collagenase with alpha2-macroglobulin is accompanied by the formation of an enzyme-inhibitor complex, which has retained no collagenolytic activity.


Studies on vitamin D and its analogs. VI. 3-deoxy-A-homovitamin D3, a model synthesis.


Integration of progeny simian virus 40 DNA into the host cell genome.


Editorial: The cross-cultural approach to medical practice.


Strength development in boys from 10 through 16 years.


Single units and sensation: a neuron doctrine for perceptual psychology?


Anomalous responses to stimulation and suppression tests in Cushing's syndrome due to a calcified adrenal adenoma.


Acute onset diabetes due to an ACTH secreting oat cell carcinoma of the bronchus.


Acute emphysematous cholecystitis.

Acute emphysematous cholecystitis.


Viral infections of the liver in childhood.


Maturation, repair and aging of the arteries as reflected in the biochemistry of the arterial smooth muscle cell.


Controlled trials of immunosuppressive therapy in hepatitis.


Electrogenetical differences of cortical auditory evoked potentials in dogs.


Infectious diseases: annual review of significant publications.


Characterization of X Gf mice with respect to their resistance to oncogensis.


Petit mal absences in night sleep with special reference to transitional sleep and REM periods.


A simple competitive protein-binding assay for cyclic adenosine 3':5'-monophosphate.


Utilization of iodine kinetic coefficients for the analysis of pharmacological responses.


Laboratory models for atherosclerosis.

Laboratory models for atherosclerosis.


Hyperlipidaemia and the pathogenesis of atherosclerosis.


Selected factors that affect the measurement of plasma progesterone concentrations in pregnant ewes.


Golgi beta-glucuronidase of androgen-stimulated mouse kidney. Subcellular fractions were prepared from mouse kidney homogenates by differential and sucrose-gradient centrifugation. A fraction enriched in Golgi apparatus was obtained, which had considerably enriched galactosyltransferase and thiamin pyrophosphatase activities, and was morphologically typical of Golgi material. This preparation also had high beta-glucuronidase activity, which increased concomitantly with microsomal beta-glucuronidase activity during the specific stimulation of the enzyme in male mouse kidney after androgen administration. The degree of stimulation was much greater in the Golgi fraction. Gel-electrophoretic patterns of Golgi beta-glucuronidase resembled more closely those of the enzyme located within lysosomes, but contained minor bands similar to those described previously (Swank & Paigen, 1973) as characteristic of the microsomal enzyme. It was concluded that the Golgi complex is involved in the distribution of the enzyme after its synthesis to both lysosomal and microsomal fractions.


Phosphodiesterase II in epithelial cells from guinea-pig and rat small intestine. Phosphodiesterase II activity was determined by using a synthetic substrate, the 2,4-dinitrophenyl ester of thymidine 3'-phosphate. The enzyme activity was determined in fractions obtained by differential centrifugation of homogenates of epithelial cells from the small intestinal mucosa of guinea pigs and rats. In guinea-pig preparations phosphodiesterase II occurred with highest specific activity in those fractions rich in succinate dehydrogenase and acid phosphatase. A lysosomal location for the guinea-pig enzyme was indicated by its structure-linked latency and by its association with particles that under-went a characteristic decrease in equilibrium density when Triton WR-1339 was injected into the animals. With rat preparations a much greater proportion of the phosphodiesterase II activity was found in the soluble fraction after ultracentrifugation. The rat enzyme exhibited a lower degree of latency and administration of Triton WR-1339 had no effect. The rat enzyme further differed from that of the guinea pig in other respects; it was more labile at 60 degrees C, it exhibited a lower pH optimum and it had a higher molecular weight as determined by gel-filtration chromatography.


Breakdown of phosphatidylinositol provoked by muscarinic cholinergic stimulation of rat parotid-gland fragments. When rat parotid fragments that had been labelled with (32)P in vivo were exposed to high concentrations of acetylcholine, radioactivity was lost from phosphatidylinositol but not from other phospholipids. Simultaneously the concentration of phosphatidylinositol in the tissue decreased. If previously unlabelled tissue was incubated with (32)P(i) an increase in incorporation of radioactivity into phosphatidylinositol was observed during this decrease in concentration. The effects of acetylcholine were blocked by atropine, but not by tubocurarine. The response to acetylcholine was rapid, with up to one-third of the tissue's phosphatidylinositol disappearing within 5min. Similar effects were evoked by stimulation with methacholine and by high concentrations of tetramethylammonium ion; these responses were also atropine-sensitive and tubocurarine-insensitive. It is concluded that the event in inositol lipid metabolism that is affected by acetylcholine stimulation is removal of the phosphorylinositol group from the molecule; this is mediated through muscarinic cholinergic receptors. This is followed by a compensatory increase in the rate of synthesis of phosphatidylinositol, which has been described in detail in the past. These observations are compared with those of previous workers and are discussed in relation to the existing hypotheses relating to the significance of stimulus-provoked phosphatidylinositol turnover.


Protein kinase activity stimulated by adenosine 3' :5'-cyclic monophosphate in synaptic-membrane fragments from ox brain. Inhibition of intrinsic activity by free and membrane-bound calcium ions. 1. Cyclic AMP-stimulated protein kinase activity phosphorylating intrinsic substrates in preparations of synaptic-membrane fragments from ox cerebral cortex was examined in relation to (a) the content of membrane-bound Ca(2+) in the preparations and (b) added Ca(2+) in the assay medium. 2. Centrifugal washing of synaptic-membrane fragments with buffered ethane dioxybis(ethylamine)tetra-acetate solutions decreased bound Ca(2+) from 2.8+/-0.4 (s.d.) to 0.9+/-0.3nmol/mg of protein. In washed preparations basal protein kinase activity was increased by about 40% and the cyclic AMP-stimulated activity by about 15%. Addition of Ca(2+) in the concentration range 5-50mum to the assay medium progressively inhibited the kinase activity of the washed preparations; in this range of Ca(2+) concentration the basal activity was inhibited more than the stimulated activity. 3. In unwashed preparations concentrations of Ca(2+) above 100mum inhibited the cyclic AMP-stimulated activity more than the basal activity. 4. The inhibitory effect of several concentrations of Ca(2+) was examined in relation to cyclic AMP concentration; no evidence for competition between Ca(2+) and cyclic AMP for a site on the enzyme was observed.


Phosphatidylinositol cleavage in lymphocytes. Requirement for calcium ions at a low concentration and effects of other cations. The soluble activity in lymphocytes which converts phosphatidylinositol into 1,2-diacylglycerol and inositol phosphates requires Ca(2+) ions. At pH7 maximum activity occurs at [Ca(2+)](free) approximately 0.7mum whereas at pH5.5 the equivalent value is approx. 50mum. At [Ca(2+)](free) approximately 1mum, a concentration similar to common intracellular values, essentially all activity is confined to the peak of activity at pH7.0. Previous reports of requirements for larger amounts of Ca(2+) may reflect the fact that the Ca(2+)-buffering capacity of phosphatidylinositol means that high substrate concentrations can effectively decrease [Ca(2+)](free). Cations which displace Ca(2+) from association with phosphatidylinositol can, at low [Ca(2+)](free), enhance enzyme activity. Phosphatidylinositol breakdown in intact cells might be controlled, at least in part, by changes in intracellular [Ca(2+)](free).


Phosphatidylinositol cleavage catalysed by the soluble fraction from lymphocytes. Activity at pH5.5 and pH7.0. Phosphatidylinositol breakdown by subcellular preparations of small lymphocytes from pig mesenteric lymph nodes was investigated. Activity was higher than in preparations from the tissues studied previously; it was recovered largely in the soluble fraction, which showed pH optima at both 5.4-5.6 and 7.0-7.3. As in other tissues, phosphatidylinositol cleavage produced 1,2-diacylglycerol and a mixture of myo-inositol 1:2-cyclic phosphate and myo-inositol 1-phosphate. It was stimulated by addition of CaCl(2) and, less effectively, by MgCl(2). On sucrose-density-gradient ultracentrifugation at pH7.0 two peaks of activity were observed (approx. sedimentation coefficients 8S and 10S); the activity profiles on the gradients were similar when assayed at pH7.0 and 5.5. Activity at pH7.0 (and 0.4mm-CaCl(2)) was decreased by agents, such as salts and lipophilic cations, which tend to neutralize the negative charge of phosphatidylinositol; at pH5.5 these agents slightly stimulated activity. It is suggested that the same enzyme(s) may be responsible for activity at both pH optima and that previous workers may have underestimated the pH7.0 activity because of the inhibitory influence of cations under the usual assay conditions.