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Biomedical subjects

W Walter

Publications and source records attributed to W Walter.

At least 55 records · Page 3Linked to original sources
PubMed1979

Altered chemical properties in three mutants of E. coli RNA polymerase sigma subunit.

We have analyzed some chemical properties of the sigma subunit of RNA polymerase from the sigma mutants: rpoD1 (Gross et al., 1978), rpoD2 (formerly known as alt-1) (Silverstone et al., 1972; Travers et al., 1978), and rpoD800 (Gross et al., 1979). Each of the three mutants is located at about 66 min on the E. coli genetic map and exhibits an alteration in the enzymatic properties of its sigma subunit. The tryptic peptides and isoelectric focusing behavior were analyzed for mutant and wild type sigma. A single, but different altered lysine tryptic peptide was observed for each mutant. No altered arginine tryptic peptides were observed. The rpoD800 mutant sigma showed an altered isoelectric point. These studies provide chemical evidence that the sigma polypeptide in all three mutants is altered and strongly support the conclusion that the mutations are in the structural gene for sigma.

Alleles↗
PubMed1979

Solubilization of membrane-bound adenylate cyclase of isolated rat adrenal cortex cells.

The membrane-bound adenylase cyclase (ATP pyrosphosphate-lyase (cyclizing), EC 4.6.1.1) of isolated rat adrenal cortex cells can be rendered soluble using 0.02 M Lubrol 12A9. The solubilized enzyme can be filtered through Milipore filters with pores 0.22 micron in diameter. Using gel filtration, on Sephadex G-200, adenylate cyclase activity was eluted with a distribution coefficient of 0.139, whereas on Sephadex G-100 the activity was eluted in the excluded volume. Half-maximum activation of the postulated guanyl nucleotide regulator site of adenylate was achieved with 5'-guanylyl-imidodiphosphate at a concentration of 1 . 10(-6)M. In contrast, however, using intact isolated rat adrenal cortex cells the guanyl nucleotide regulator site could not be stimulated by 5'-guanylyl-imidodiphosphate.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1979

[A prospective trial on osteoporosis following bilateral ovariectomy with and without oestrogen replacement (author's transl)].

During four years a prospective study was carried out on 59 women, who had ovariectomized bilaterally for non-malignant diseases. It was studied the loss of the body length, the loss of bone mineral content in a middle phalanx expressed as percentage and several x-ray criteria. By means of combined performance signs of a beginning osteoporosis were found in 59 per cent of women after 2 years and in 68 per cent after 4 years after ovariectomy. -- The authors recommend relative simple screening methods: observation of body length, the dual beam x-ray spectrophotometry (Krokowski) and the minimal combined cortex thickness of the proximal radius according Meema. Women undergoing ovariectomy before the menopause should be attended by medical teamwork. The results of oestrogen prophylaxis were not so convincing as other investigators described.

Adult↗
PubMed1977

[Growth hormone, LH and FSH under function dynamical conditions in serum and basic corticol and testosterone serum levels in brain-injured patients during dexamethasone treatment].

In 14 male patients with severe head injury the following hormones were measured by radioimmunological methods in plasma: Basal levels of LH, FSH, GH, testosterone and total corticoids; furthermore LH-releasing-hormone- and insulin-hypoglycaemia-tests were done. The investigations have shown, that in patients with severe head injury no essential impairment of the hypothalamus-hypophyseal-system controlled by LH-, FSH- and GH-secretion could be detected. Diminished testosterone and accelerated LH-levels are measurable, whereas total corticoids were not significantly accelerated. Because of treatment with dexamethasone the effect of this substance has to be discussed.

Adolescent↗
PubMed1977

Biosynthesis of thiamin in Bacillus subtilis. Isolation of mutants accumulating 4-amino-5-hydroxymethyl-2-methylpyrimidine phosphate.

Thiamin-deficient mutants of Bacillus subtilis were characterized by their growth responses to the pyrimidine and thiazole moieties of the vitamin molecule and by cross-feeding tests. All mutants growing on the thiazole moiety and all mutants with an absolute requirement for thiamin fed all those growing on the pyrimidine moiety. No other cross-feeding effects were observed. From the culture fluid of a mutant growing on the thiazole moiety, two compounds were isolated which supported growth of mutants requiring the pyrimidine moiety. These compounds were identified by chromatographic, bioautographic and spectrophotometric procedures as 4-amino-5-hydroxymethyl-2-methylpyrimidine and its monophosphate derivative.

Bacillus subtilis↗
PubMed1976

Leukocyte-derived complement inhibitor. IV. The functional properties of C1 bound to erythrocytes pretreated with leukocyte culture supernatant.

E, pretreated with leukocyte cultures supernatant (ES), binds C1 through C1q; ES and EIgM that bind the same amount of C1 as measured in a hemolytic assay have the same uptake of 125I-C1q; ESC1q and EIgMC1q, carrying the same number of molecules of CUq per cell, have the same uptake of CUr and CUs; soluble immune compleses prevent the binding of C1 and C1q to ES. The activity of C1 bound to ES is impaired; ESC1 can react with C4 but not with C2. The C4 turnover and the C1 ING turnover by ESC1 are reduced so that ES-bound C1 is protected from destruction by C1 ING. These modifications are fully reversed when C1 is transferred from ES to EA:C1 recovers its ability to react with C2, and C1 INH. Thus the C1s activity can be modulated inside the C1 molecular complex upon binding of C1q to a lymphocyte product. In addition, the 125I-C1q uptake is proportional to the amount of IgM hemolysin used to sensitize E; it has, however, an exponential relationship to the amount of IgG or S used to sensitize E. The ratio of 125I-C1q uptake towhole C1 uptake measured in a hemolytic assay is lowerthan 2. This indicates that one molecule of IgM is sufficient to bind one molecule of C1q on E, that several molecules of IgG or S are required to bind one molecule of C1q, and that one molecule of C1q is sufficient to create a lytic site on E.

Animals↗