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J Williams

Publications and source records attributed to J Williams.

At least 1,081 records · Page 60Linked to original sources
PubMed1979

Location of additional early gene sequences in the adenoviral chromosome.

Genetic and biochemical analysis has revealed additional early gene sequences in the group C human adenovirus genome. Physical mapping by an improved marker rescue method showed that a group of "early function" mutations previously found by us to map within the left quarter of the genome do not map within the known early sequence (0-11.2) in that region, but instead lie within the coordinates 18.5-22.0. A search for early expression in this region of the genome using saturation hybridization techniques showed the presence of two discrete sets of viral cytoplasmic RNA sequences, present early in infection at low copy number and complementary to sequences on the I strand of the adenovirus genome lying between 11.2-14.5 and 19.8-23.5 untis.

Adenoviruses, Human↗
PubMed1979

The treatment of femoral fractures by cast-brace and early walking: a review of seventy-nine patients.

Seventy-nine cases of fracture of the femoral shaft treated by cast-brace and early walking have been reviewed. Discrepancy in femoral length was assessed by scanogram. The cases were analysed to relate the incidence of shortening greater than 2 centimetres to the type and site of the fracture, and the time which elapsed from injury until the cast-brace was applied. Such shortening was encountered most frequently when the cast-brace was applied within the first two weeks from injury or after six weeks and in those patients with comminuted fractures of the middle third of the femoral shaft.

Adult↗
PubMed1979

Plasma testosterone levels in intact and hemicastrated growing cockerels.

Changes in the levels of testosterone in plasma were measured by radioimmunoassay in blood samples taken at frequent intervals between 2 and 26 weeks of age from entire cockerels and cockerels hemicastrated before 2 weeks of age. In both groups the pattern of testosterone secretion could be divided into three clearly defined phases. In young birds, the levels of testosterone in plasma were low (0.3 ng/ml) but in the prepubertal period, at 11 weeks of age, they started to rise and continued to rise until 22 weeks of age when adult levels, which fluctuated between 2.5 and 3.5 ng/ml, were reached. In the immediate period after hemicastration, the concentration of testosterone decreased temporarily. From 11 weeks of age the levels of testosterone in the hemicastrated birds were approximately 75% of those in intact birds. These results are discussed in relation to the compensatory testicular hypertrophy which occurs in growing cockerels hemicastrated at an early age.

Animals↗
PubMed1979

Effects of picrotoxin, naloxone, and vagotomy on chlordiazepoxide-induced respiratory depression.

Intravenous administration of chlordiazepoxide (CDP) caused respiratory depression in both rats and cats. The maximally tolerated dose of CDP was found to be 165 +/- 15 mg/kg, i.v., in rats. Pretreatment with picrotoxin (1.5 mg/kg) or naloxone (20 mg/kg, i.v.) significantly increased the maximally tolerated dose of CDP to 330 +/- 40 mg/kg, i.v., and 270 +/- 35 mg/kg, i.v., respectively. The protective effects of both naloxone and picrotoxin were absent in bilaterally vagotomized rats. Naloxone pretreatment (25 mg/kg, i.v.) was also found to block the respiratory depressant effects of CDP in anesthetized cats, but had no effect on the cardiovascular actions of CDP. It is possible that the respiratory effects of CDP are due to its actions on GABA receptors, and that peripheral GABA receptors may mediate the protective actions of picrotoxin and naloxone.

Animals↗
PubMed1978

alpha-Galactosidases II, III and IV from seeds of Trifolium repens. Purification, physicochemical properties and mode of galactomannan hydrolysis in vitro.

Five alpha-galactosidases (alpha-D-galactoside galactohydrolase, EC 3.2.1.22) were identified by chromatography and by their different electrophoretic mobilities, in the germinated seeds of Trifolium repens (white clover). alpha-Galactosidases II, III and IV were purified to homogeneity, with increases in specific activity of approx. 4600-, 4900- and 2800-fold respectively. The enzymes were purified by a procedure that included (NH4)2SO4 precipitation, hydroxyapatite, Sephadex G-75 and DEAE-cellulose chromatography, and preparative polyacrylamide-gel disc electrophoresis. The purified enzymes showed a single protein band, corresponding to the alpha-galactosidase activity, when examined by polyacrylamide-gel electrophoresis. The pH optimum was determined with o-nitrophenyl alpha-D-galactoside and the galactomannan of T. repens To as substrate. All three enzymes are highly thermolabile. Hydrolysis of oligosaccharides and galactomannans was examined, including two galactomannans from the germinated seed of T. repens (T24 and T36). By sodium dodecyl sulphate/polyacrylamide-gel electrophoresis the mol.wts. of the multiple forms of enzyme were found to be identical (41 000).

Galactans↗
PubMed1978

Purification and properties of beta-mannanases I and II from the germinated seeds of Trifolium repens. Mode of galactomannan degradation in vitro.

Two beta-mannanases (beta-mannosidases, EC 3.2.1.25) purified from the germinated seeds of Trifolium repens by a procedure that included chromatography on hydroxyapatite, gel filtration on acrylamide/agarose (Ultragel 5/4) and preparative polyacrylamide-gel-electrophoresis. The final purification step completely resolved two beta-mannanases with distinct specificities, which were termed beta-mannanase I and beta-mannanase II. beta-Mannanase I was purified 1400-fold and beta-mannanase II 1000-fold. The purified enzymes showed a single protein band when examined by polyacrylamide-gel disc electrophoresis. beta-Mannanase I, apparent mol.wt. 43 000, accounted for 49% of the total activity recovered from the final step of purification. beta-Mannanase II, apparent mol.wt. 38 000, accounted for the remaining 51% of activity. Molecular-weight determinations were by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and by the electrophoretic method of Hendrick & Smith [(1968) Arch. Biochem. Biophys. 126, 155-164]. The substrate specificities of both enzymes were examined with the galactomannans of T. repens and of Medicago sativa, as well as with manno-oligosaccharides. The pH optimum was between pH 5.1 and 5.6 for both enzymes.

Enzyme Activation↗
PubMed1978

The iron-binding properties of hen ovotransferrin.

1. The distribution of iron between the two iron-binding sites in partially saturated ovotransferrin was studied by labelling with 55Fe and 59Fe and by gel electrophoresis in a urea-containing buffer. 2. When iron is added in the form of chelate complexes at alkaline pH, binding occurs preferentially at the N-terminal binding site. In acid, binding occurs preferentially at the C-terminal site. 3. When simple iron donors (ferric and ferrous salts) are used the metal is distributed at random between the binding sites, as judged by the gel-electrophoresis method. The double-isotope method shows a preference of ferrous salts for the N-terminal site. 4. Quantitative treatment of the results of double-isotope labelling suggests that in the binding of iron to ovotransferrin at alkaline pH co-operative interactions between the sites occur. These interactions are apparently absent in the displacement of copper and in the binding of iron at acid pH.

Binding Sites↗
PubMed1978

Studies of the binding of different iron donors to human serum transferrin and isolation of iron-binding fragments from the N- and C-terminal regions of the protein.

1. Trypsin digestion of human serum transferrin partially saturated with iron(III)-nitrilotriacetate at pH 5.5 or pH 8.5 produces a carbohydrate-containing iron-binding fragment of mol.wt. 43000. 2. When iron(III) citrate, FeCl3, iron (III) ascorabate and (NH4)2SO4,FeSO4 are used as iron donors to saturate the protein partially, at pH8.5, proteolytic digestion yields a fragment of mol.wt. 36000 that lacks carbohydrate. 3. The two fragments differ in their antigenic structures, amino acid compositions and peptide 'maps'. 4. The fragment with mol.wt. 36000 was assigned to the N-terminal region of the protein and the other to the C-terminal region. 5. The distribution of iron in human serum transferrin partially saturated with various iron donors was examined by electrophoresis in urea/polyacrylamide gels and the two possible monoferric forms were unequivocally identified. 6. The site designated A on human serum transferrin [Harris (1977) Biochemistry 16, 560--564] was assigned to the C-terminal region of the protein and the B site to the N-terminal region. 7. The distribution of iron on transferrin in human plasma was determined.

Amino Acids↗
PubMed1978

Iron-binding fragments from the N-terminal and C-terminal regions of human lactoferrin.

Digestion of lactoferrin with pepsin at pH3.0 gave an iron-binding half-molecule that represents the C-terminal part of the native protein. Tryptic or chymotryptic digestion of 30%-iron-saturated lactoferrin yielded the N- and C-terminal half molecules, which could be separated by DEAE-Sephadex chromatography. The N- and C-terminal fragments did not show any immunological cross-reaction. The carbohydrate of lactoferrin was distributed equally between the two fragments.

Amino Acids↗