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Biomedical subjects

C Wagner

Publications and source records attributed to C Wagner.

At least 271 records · Page 15Linked to original sources
PubMed1985

Familial embryonal carcinoma in a cancer-prone kindred.

Familial testicular cancer is rare. This report describes a family with an unusual cancer spectrum that included the infantile form of embryonal carcinoma of the testis in the son of a cancer-free but putative obligate gene carrier mother, and the adult form of embryonal carcinoma in this women's maternal half-brother (their mutual mother had malignant melanoma and urinary bladder carcinoma). Hereditary syndrome designation remains elusive. Priority attention to biomarker research in families of this type for elucidation of cause and control is discussed.

Adult↗
PubMed1985

Measurement of dimethylglycine in biological fluids.

The method of quantitating N,N-dimethylglycine involves cation-exchange high-performance liquid chromatography and detection of dimethylglycine with dimethylglycine dehydrogenase. Dimethylglycine was added to plasma and urine and samples were assayed for dimethylglycine. Plasma and urine to which no dimethylglycine was added were also assayed. Recoveries of added dimethylglycine were 99 to 104% with no endogenous dimethylglycine found in rat plasma or normal human urine. The human plasma used contained a small amount of endogenous dimethylglycine. The cation-exchange chromatography separates dimethylglycine from other compounds which can serve as substrates for dimethylglycine dehydrogenase. Repeatability of the assay is +/- 10%. Using this method we have identified dimethylglycine in the urine of a 1-month-old female human patient.

Carbon Radioisotopes↗
PubMed1985

Enzymatic properties of dimethylglycine dehydrogenase and sarcosine dehydrogenase from rat liver.

Dimethylglycine dehydrogenase (EC 1.5.99.2) and sarcosine dehydrogenase (EC 1.5.99.1) are flavoproteins which catalyze the oxidative demethylation of dimethylglycine to sarcosine and sarcosine to glycine, respectively. During these reactions tightly bound tetrahydropteroylpentaglutamate (H4PteGlu5) is converted to 5,10-methylene tetrahydropteroylpentaglutamate (5,10-CH2-H4PteGlu5), although in the absence of H4PteGlu5, formaldehyde is produced. Single turnover studies using substrate levels of the enzyme (2.3 microM) showed pseudo-first-order kinetics, with apparent first-order rate constants of 0.084 and 0.14 s-1 at 23 and 48.3 microM dimethylglycine, respectively, for dimethylglycine dehydrogenase and 0.065 s-1 at 47.3 microM sarcosine for sarcosine dehydrogenase. The rates were identical in the absence or presence of bound tetrahydropteroylglutamate (H4PteGlu). Titration of the enzymes with substrate under anaerobic conditions did not disclose the presence of an intermediate semiquinone. The effect of dimethylglycine concentration upon the rate of the dimethylglycine dehydrogenase reaction under aerobic conditions showed nonsaturable kinetics suggesting a second low-affinity site for the substrate which increases the enzymatic rate. The Km for the high-affinity active site was 0.05 mM while direct binding for the low-affinity site could not be measured. Sarcosine and dimethylthetin are poor substrates for dimethylglycine dehydrogenase and methoxyacetic acid is a competitive inhibitor at low substrate concentrations. At high dimethylglycine concentrations, increasing the concentration of methoxyacetic acid produces an initial activation and then inhibition of dimethylglycine dehydrogenase activity. When these compounds were added in varying concentrations to the enzyme in the presence of dimethylglycine, their effects upon the rate of the reaction were consistent with the presence of a second low-affinity binding site on the enzyme which enhances the reaction rate. When sarcosine is used as the substrate for sarcosine dehydrogenase the kinetics are Michaelis-Menten with a Km of 0.5 mM for sarcosine. Also, methoxyacetic acid is a competitive inhibitor of sarcosine dehydrogenase with a Ki of 0.26 mM. In the absence of folate, substrate and product determinations indicated that 1 mol of formaldehyde and of sarcosine or glycine were produced for each mole of dimethylglycine or sarcosine consumed with the concomitant reduction of 1 mol of bound FAD.

Anaerobiosis↗
PubMed1985

Isolation and chemical structure of aklanonic acid, an early intermediate in the biosynthesis of anthracyclines.

The fermentation, isolation and structure elucidation of aklanonic acid are described. The compound was isolated from fermentations of Streptomyces strain ZIMET 43,717. Aklanonic acid is a yellow-orange crystalline substance, melting at 203-204 degrees C (dec), having the molecular formula C21H16O8, and possessing UV maxima at 258, 282 (sh) and 438 nm (CHCl3). In dimethyl sulfoxide or pyridine aklanonic acid is unstable and a new compound (aklanone) is formed as a conversion product. The elucidation of the structures has shown that aklanonic acid and aklanone are derivatives of 1,8-dihydroxyanthraquinone.

Anthraquinones↗
PubMed1985

[Development of a numerically additive combined vaccine against tetanus and smallpox].

Mandatory vaccination against smallpox was abolished on the account of smallpox-eradication proclaimed by the WHO and the postvaccinal complications detected after smallpox vaccination. At the same time vaccine banks with the vaccinia virus strain "Elstree" were organized. Should mass vaccinations with this vaccinia virus strain be carried out in a case of emergency, severe postvaccinal diseases and complications can arise in overaged and immunosuppressed vaccinees after primovaccination. Therefore attenuated vaccinia virus strains should be used for vaccine banks, which cannot be activated, or increase in virulence in impaired vaccinees after primovaccination. For these individuals the vaccinia virus strain "MVA", among other attenuated vaccinia strains, is recommended. The MVA virus strain can be applied parenterally without complications. From the scientific and field-relevant point of view it was tried to combine the vaccinia virus strain "MVA" with tetanus toxoid and to develop a combination vaccine "tetanus-smallpox". In immunization experiments using mice, piglets and monkeys, safety and efficacy of the vaccine were investigated. Efficacy was demonstrated by means of postvaccinal antibody determination and by the mouse protection test. Tetanus antitoxin was measured by ELISA and indirect hemagglutination test, antibody levels to vaccinia virus were investigated employing the neutralization test and hemagglutination inhibition test. No significant differences in potency could be demonstrated between the combination vaccine and the corresponding monovalent vaccines in mice, piglets and monkeys. The combination vaccine consisted of 12 Lf tetanus toxoid and 10 TCID50 vaccinia virus "MVA" preserved with gelatine and glucosamine. The double intramuscular immunization of monkeys stimulated average tetanus antitoxin titers of 1:310 and average vaccinia virus titers of 1:195 2 weeks p. revacc. Similar results were obtained in mice and piglets. Side reactions were not observed in mice and piglets. Except for occasional local reactions of short duration at the injection site of the monkeys, similarly no adverse reactions were observed after intramuscular vaccination with the combination vaccine.

Adjuvants, Immunologic↗
PubMed1985

Localization of phosphatidylethanolamine in the plasma membrane of diamide-treated human blood platelets.

In human blood platelet plasma membranes phosphatidylethanolamine (PE) is asymmetrically distributed between the two leaflets. The main part of this phospholipid is localized at the inner half of the lipid bilayer. Upon stimulation of the cell a substantial transbilayer movement of PE as well as phosphatidylserine occurs and the outer leaflet then provides a procoagulant surface. The thrombin-induced PE flip-flop is inhibited by pretreatment of platelets with diamide, whereas pretreatment of platelets with diamide alone up to 5 mM did not change considerably the localization of PE in the platelet membrane. Thus, cytoskeletal proteins, which are modified by diamide, are not involved in the maintenance of the PE asymmetry but are important for the realization of the agonist-induced events in the platelets.

Adenosine Diphosphate↗
PubMed1984

Identification of the covalently bound flavin of dimethylglycine dehydrogenase and sarcosine dehydrogenase from rat liver mitochondria.

Dimethylglycine dehydrogenase (EC 1.5.99.2) and sarcosine dehydrogenase (EC 1.5.99.1) are the folate binding proteins of rat liver mitochondria. These two enzymes contain covalently bound flavin and catalyze similar oxidative demethylation reactions (Wittwer, A. J., and Wagner, C. (1981) J. Biol. Chem. 256, 4102-4108). Flavin-peptides have been purified from these two enzymes after proteolytic digestion by trypsin and chymotrypsin. The spectral and chromatographic properties of these flavin peptides changed after treatment with nucleotide pyrophosphatase in a manner consistent with the conversion of an FAD-peptide to an FMN-peptide. The pKa for pH-dependent fluorescence quenching of the purified flavin-peptides was not affected by borohydride reduction which, in conjunction with the pKa values, indicated that the flavin was covalently linked via the 8 alpha position of the isoalloxazine ring to an imidazole N(3) of a histidine residue. Peptides from both enzymes showed histidylflavin at the N terminus. Amino acid composition and sequence analysis showed that the flavin-peptide from dimethylglycine dehydrogenase was His(flavin)-Ala-Ala-Gly-Leu. Amino acid composition and N-terminal analysis suggested the sequence of the flavin-peptide of sarcosine dehydrogenase was His(flavin)-(Ala, Gly,Thr)-Leu.

Amino Acids↗
PubMed1984

[Leukemomycin-blocked mutants of Streptomyces griseus and their pigments. II. New 7-hydroxy-bisnahydro-rhodomycinones from the mutant ZIMET 41707/1P].

Various blocked mutants were isolated from three leukaemomycin-(daunomycin-)producing strains IMET JA 3933, IMET JA 5142 and IMET JA 5570 of Streptomyces griseus by NTG and UV treatments. Among them, one class of four mutants ZIMET 43707/1P, IMET JA 5570/3P, IMET JA 5570/10P and IMET JA 5142/01P1 produced new blue and red pigments. Two red compounds designated 1PI and 1PII are the main components of the pigment complex produced by culture of the blocked mutant ZIMET 43707/1P. This paper describes the isolation of 1PI and IPII; furthermore, the spectral and physicochemical properties of these anthracyclinones and the elucidation of their structures are reported.

Chemical Phenomena↗
PubMed1984

Covalent binding of folic acid to dimethylglycine dehydrogenase.

Dimethylglycine dehydrogenase (EC 1.5.99.2) carries out the oxidative demethylation of dimethylglycine to sarcosine in liver mitochondria. In vivo, the enzyme uses tightly bound tetrahydropteroyl pentaglutamate (H4PteGlu5) as an acceptor of the one-carbon group generated during the reaction. The purified enzyme can use, but does not require, H4PteGlu5 and under these conditions formaldehyde is the one-carbon unit produced. It is reported that folic acid may be covalently linked to dimethylglycine dehydrogenase in a specific and saturable manner so that only 1 mole of folic acid is bound per mole of enzyme. Covalently bound folic acid blocks the subsequent binding of H4PteGlu, and does not inhibit the rate of dimethylglycine dehydrogenase activity in vitro.

Animals↗
PubMed1984

Glycine N-methyltransferase is a folate binding protein of rat liver cytosol.

A comparison of the amino acid compositions of one of the folate-binding proteins of rat liver cytosol, folate-binding protein-cytosol II, and that of glycine N-methyltransferase (S-adenosyl-L-methionine:glycine methyltransferase, EC 2.1.1.20) from the same source indicated a great deal of structural homology between the two proteins. Antiserum prepared against the purified folate-binding protein almost completely inactivated the enzyme activity in crude liver cytosol. Purification of glycine N-methyltransferase resulted in the separation of two enzyme species, one that contained bound folate and one that did not. Each species was homogeneous, as judged by NaDodSO4/polyacrylamide gel electrophoresis, and they migrated identically.

Amino Acids↗
PubMed1982

Purification and partial characterization of rat liver folate binding protein: cytosol I.

The high molecular weight folate binding protein of rat liver cytosol has been purified to apparent homogeneity. Purification was achieved by using a combination of gel filtration, O-(diethylaminoethyl)cellulose chromatography, and affinity chromatography. This folate binding protein was initially identified during purification by an in vivo labeling procedure involving intraperitoneal injection of [3H]folic acid prior to sacrifice and subsequently by its ability to bind naturally reduced [3H]folate polyglutamates in vitro. A molecular weight of 210 000 was estimated by gel chromatography. This is distinct from the trifunctional formyl-methenyl-methylene synthetase of rat liver which has a molecular weight of 225 000. Sodium dodecyl sulfate electrophoresis revealed a single band with a molecular weight of about 100 000 which suggests the native protein is composed of two identical subunits. The partially purified protein contains bound tetrahydropteroylpentaglutamate.

Animals↗
PubMed1982

Cellular folate binding proteins; function and significance.

It appears that specific functions may be assigned to some of the cellular folate binding proteins with some degree of certainty. Those that are membrane bound or derived from membranes probably have a role in transport of folate molecules into the cell. This is in spite of the fact that the localization of this protein to the plasma membrane has been carried out in only a limited number of cases. The role of the folate binding protein of L. casei in transport is much clearer. Bacteria provide the opportunity to obtain mutants defective in both transport and binding, and such mutants are more difficult to obtain with mammalian cell lines. The intracellular folate binding proteins have been discovered so far only in liver. The fact that the folate binding proteins in rat liver mitochondria are two enzymes, dimethylglycine dehydrogenase and sarcosine dehydrogenase, suggests that enzyme activities may eventually be discovered for the other intracellular folate binding proteins. This may not possible, however, and a reasonably strong case has been made that the folate binding protein of cytosol, FBP-CII, serves in a storage role. Such a storage role is difficult to prove since it depends, in part, on the demonstration that the protein becomes progressively less saturated during deficiency--a situation true also for enzymes.

Animals↗