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Biomedical subjects

R E Williams

Publications and source records attributed to R E Williams.

At least 127 records · Page 7Linked to original sources
PubMed1987

Double-blind study comparing aztreonam with placebo for prophylaxis of infection following prostatic surgery.

In a prospective, randomised, double-blind study, 179 patients undergoing retropubic or transurethral prostatectomy were given pre-operatively either 1 g aztreonam or a placebo. In patients treated with aztreonam there was a significant reduction in the number with post-operative bacteriuria and in the number requiring treatment of post-operative bacteriuria. Other differences were not significant. The mean duration of post-operative hospital stay for patients receiving aztreonam was 7.1 days compared with 6.9 days for those receiving placebo. In patients treated with aztreonam there was no increase in the frequency of infections due to Gram-positive bacterial species.

Aztreonam↗
PubMed1986

Influence of hog lice, Haematopinus suis, on blood components, behavior, weight gain and feed efficiency of pigs.

Blood components, behavior, weight gain and feed efficiency were studied in 40 weaner pigs infested with lice and 40 left uninfested (controls). Packed cell volumes and concentrations of hemoglobin, serum proteins, leukocytes, serum globulins, and serum albumins increased significantly in both groups. Eosinophil concentrations increased and neutrophil concentrations decreased in the infested group but not in the controls. There was a significant increase in erythrocyte concentrations in the control group while the infested group's erythrocyte concentrations decreased at the middle of the experiment. Blood of infested and uninfested pigs showed no significant differences from pre-infestation values in sedimentation rates and concentrations of fibrinogen, basophils, and monocytes. Control pigs spent more time at feeders and more time active while not at feeders. Nevertheless, average daily gains (ADG) and feed efficiencies (FE) of the two groups were not significantly different. When ADG and FE were grouped by severity of Haematopinus suis infestation, pigs with more H. suis had higher ADG and better FE than pigs with fewer or no lice. The results suggest that a decrease in activity by infested pigs allows them to save energy which is then available for growth.

Animals↗
PubMed1986

A comparison of the effect of diethylstilbestrol with low dose estramustine phosphate in the treatment of advanced prostatic cancer: final analysis of a phase III trial of the European Organization for Research on Treatment of Cancer.

In a randomized phase III trial performed by the Urological Group of the European Organization for Research on Treatment of Cancer low dose estramustine phosphate (280 mg. twice daily for 8 weeks and 140 mg. twice daily thereafter) was compared to diethylstilbestrol (1 mg. 3 times daily) in patients with stages T3 to T4, M0 or M1 prostatic cancer. Of 248 patients entered 227 were evaluable for analysis: 115 received estramustine phosphate and 112 received diethylstilbestrol. The best response of the local tumor as assessed by palpation was seen in patients receiving diethylstilbestrol. There was no significant difference between treatments for response rate of metastases, interval to local progression, distant progression, over-all survival and death of carcinoma of the prostate. Duration of survival was correlated with the assessment of local response as determined by palpation. The response of distant lesions also was correlated closely with survival. Diethylstilbestrol (1 mg. 3 times daily) was associated with a significantly worse degree of cardiovascular toxicity than estramustine phosphate. This finding was especially obvious in patients who had no history of cardiovascular disease. Gastrointestinal toxicity occurred in 25 patients treated with estramustine phosphate, including 6 in whom cessation of treatment was necessary. Further studies are required to determine the optimum dose of diethylstilbestrol and estramustine phosphate, and to establish the best form of hormonal treatment for prostatic carcinoma.

Aged↗
PubMed1985

The circular dichroism of phosphocholine-specific mouse hybridoma and myeloma proteins: unusual properties of the hybridoma protein 101.6G6.

The circular dichroism (CD) spectra of five myeloma and six hybridoma proteins specific for phosphocholine were measured in the 250-310-nm range. The effect on the CD spectra of adding phosphocholine was also examined. The five myeloma proteins all had distinctive native spectra and, except for M603 and W3207, unique changes occurred on ligand binding. The hybridomas were chosen as pairs from each of the three known families of phosphocholine-specific immunoglobulins. Those from the T15 or M603 families resembled the appropriate prototype. However, the proteins from the M167 family were all distinctively different in their CD properties. In particular, the hybridoma protein 101.6G6 showed large CD changes on hapten binding and values for the association constant for phosphocholine of 1.1 X 10(5) M-1 and of 5.8 X 10(2) M-1 for acetylcholine were obtained by CD spectrophotometric titration. The CD properties of the proteins are interpreted in the light of the sequence data so far available, including the possible role of the D-segment.

Acetylcholine↗
PubMed1985

Assignment of lectins specific for D-galactose or N-acetyl-D-galactosamine to two groups, based on their circular dichroism.

The circular dichroism (CD) spectra of thirteen lectins, most being specific for D-galactose or N-acetyl-D-galactosamine, were compared. Two groupings are proposed on the basis of the CD in the near-ultraviolet region. Group one comprises the lectins from Arachis hypogaea, Glycine max, Phaseolus coccineus, P. lunatus, P. vulgaris, and Vicia villosa, and group two comprises lectins from Caragana arborescens, Cytisus sessilifolius, Dolichos biflorus, Griffonia simplicifolia, and Wisteria floribunda. The CD spectra of lectins from Bauhinia purpurea and Sophora japonica were different from any of the other lectins. CD difference spectra produced by the two sugars were distinctive for each protein, suggesting that the combining sites of these lectins are not homologous despite similarities in specificity and that the CD spectral similarities arise from residues in other, more homologous regions of the proteins.

Acetylgalactosamine↗
PubMed1984

Structural differences between two lectins from Cytisus scoparius, both specific for D-galactose and N-acetyl-D-galactosamine.

Three lectin fractions were obtained from seeds of the leguminous plant Cytisus scoparius (Scotch broom) by means of affinity chromatography on a N-acetyl-D-galactosamine medium. The first fraction, termed CSIa, was equally well inhibited in haemagglutination experiments by D-galactose and by N-acetyl-D-galactosamine and consisted of a group of isolectins formed from closely related polypeptide chains of approx. Mr 30000. The second fraction, CSIb, was closely related to CSIa in specificity, c.d. and other properties. The third fraction contained a homogeneous lectin, CSII, formed from subunits again of approx. Mr 30000. CSII was 100 times more readily inhibited by N-acetyl-D-galactosamine than by D-galactose. Despite the similarity in specificity, comparative studies of their amino acid composition, c.d. and N-terminal amino acid sequence showed that the CSIa and CSII lectins diverged considerably in structure. The lectin from Cytisus sessilifolius, specific for chitobiose, was also examined and resembled CSIa in composition and c.d. properties.

Acetylgalactosamine↗
PubMed1984

Chemical modification and serological properties of the 3-deoxy-alpha-D-manno-2-octulosonic acid-containing polysaccharide from Escherichia coli LP1092.

The alpha-D configuration of the 3-deoxy-D-manno-2-octulosylonic acid residues in the E. coli LP1092 polysaccharide was definitively assigned by a comparison of its c.d. spectrum with those of methyl 3-deoxy-alpha- and -beta-D-manno-2-octulopyranosidonic acid. The c.d. spectrum of the polysaccharide showed a negative n----pi transition at 211 nm, associated with carboxyl groups, which correlated well with the negative band at 218 nm exhibited in the c.d. spectrum of the methyl alpha-D-glycoside. In contrast, the methyl beta-D-glycoside gave a positive band in the same region of its c.d. spectrum, at 221 nm. Treatment of the E. coli LP1092 polysaccharide with 3-(3-dimethylaminopropyl)-1-ethylcarbodiimide hydrochloride yielded a modified polysaccharide containing O-acylisourea groups and intramolecular lactones, in addition to some unesterified carboxyl groups. Both forms of ester could be reduced to hydroxymethyl groups by sodium borohydride. Although immuno-precipitation of an antiserum specific for the E. coli LP1092 polysaccharide is not sensitive to the introduction of O-acylisourea groups into the polysaccharide, precipitation was completely eliminated when approximately half of the carboxyl groups of the polysaccharide were converted either into lactone or hydroxymethyl groups. Failure to precipitate the antiserum can be attributed to significant conformational changes in the polysaccharide brought about by the introduction of the latter two groups.

Carbohydrate Conformation↗
PubMed1984

Conformational changes induced by binding of bivalent cations to oncomodulin, a paravalbumin-like tumour protein.

When Mg2+ was added to rat oncomodulin, a paravalbumin-like tumour protein, changes in the c.d. spectrum and tyrosine fluorescence intensity were observed. The addition of Ca2+ resulted in even greater changes in these spectra. The fluorescence excitation spectra of apo- and Mg-oncomodulin were superimposable, whereas that of Ca-oncomodulin was markedly different. The u.v.-absorption spectrum of the Ca2+ form also showed major differences from those of the other two forms. These observations indicate that Ca2+ induced a significant and specific conformational change in the protein that was not observed on binding Mg2+. In contrast, the conformational change induced by either Mg2+ or Ca2+ was identical in the homologous rat parvalbumin. This Ca2+-specific conformational change may be the basis for oncomodulin's Ca2+-dependent protein/protein interaction.

Animals↗
PubMed1984

Immobilization of isolated and cellular hydrogenase of D. desulfuricans in radiation-polymerized polyacrylamides.

Purified hydrogenase from Desulfovibrio desulfuricans was immobilized either by entrapment or absorption onto porous neutral and charged acrylamide beads. Surface absorption and crosslinking on the beads resulted in a high hydrogenase activity and a good immobilization coefficient compared to the enzyme and whole cells entrapped in the same matrix. Maximum enzyme activity (citrate-phosphate buffer) was shifted to pH 6.5 upon immobilization in contrast to 6.0 for the free enzyme and the range of 6-7 for whole cells. Both the purified enzyme and whole cells were most active when held in neutral matrices. Immobilization improved the temperature stability (65 degrees C) and long term storage (4 degrees C) of the hydrogenase activity of both the purified enzyme and whole cells.

Acrylic Resins↗
PubMed1984

Application of hydrophobic chromatography to the large scale purification of Desulfovibrio desulfuricans cytochrome C3.

Hydrophobic chromatography on Phenyl-Sepharose was employed for large scale purification of cytochrome c3 from Desulfovibrio desulfuricans. This chromatographic procedure minimizes operational volumes and eliminates the lengthy dialysis ordinarily used to remove large amounts of salts. Pure cytochrome c3 was obtained after one additional purification by ion-exchange chromatography.

Amino Acids↗
PubMed1983

Self-association of the cardiac fatty acid binding protein. Influence on membrane-bound, fatty acid dependent enzymes.

The present study on the fatty acid binding protein, purified from pig heart and studied by three independent techniques (electron spin resonance, circular dichroism, and polyacrylamide gel electrophoresis), suggests that the protein self-aggregates and exists in at least four distinct molecular species. This plurality is demonstrated by the presence of four bands after electrophoretic migration at pH 7.2 and by three transitions of molar ellipticity theta 225 that depend on protein concentration. A mathematical model is formulated to simulate the three transitions and to calculate the concentrations of the four species. The multistates manifest themselves in a complex binding capacity for fatty acid, with two sigmoidal components in the binding curve. A general equation for the curve is formulated, and the characteristic constants are evaluated by a nonlinear least-squares fit. The experimental results and their interpretation in quantitative terms lead to a theoretical evaluation of the importance of this new property of self-aggregation of the protein on the activity of membrane-bound model enzymes which are fatty acid or acyl coenzyme A dependent.

Animals↗
PubMed1983

The circular dichroism of ovoverdin and other carotenoproteins from the lobster Homarus americanus.

The circular dichroic (CD) spectra of the alpha-, beta'-, and gamma-crustacyanins, ovoverdin, and the yellow lobster-shell protein were measured in the region 200-750 nm, for comparison with the CD spectrum of the free carotenoid astaxanthin. The two carotenoid chromophores of ovoverdin gave a CD spectrum with a series of bands of alternating sign and ellipticities up to 1.9 X 10(5) degree X cm2 X dmol-1, comparable to the low temperature CD spectrum of astaxanthin in the UV region. The visible region of ovoverdin also contained strong CD bands where astaxanthin itself has very weak ones. The blue (640 nm) chromophore of ovoverdin gave a broad negative CD feature quite different from the blue chromophores of the three crustacyanins. The crustacyanins have a broad positive feature between 400 and 610 nm with ellipticities up to 2 X 10(5) degree X cm2 X dmol-1, followed at higher wavelengths by a negative band with an ellipticity up to 1 X 10(5) degree X cm2 X dmol-1. Gaussian curve-fitting procedures showed the positive features to consist of a minimum of two or three CD bands. In addition to the exciton bands at the main visible absorption, the yellow lobster-shell protein had a pair of CD bands of equal but opposite ellipticity associated with an absorption band between 250 and 340 nm. The UV regions of the CD spectra of the five carotenoproteins have bands from both carotenoid and protein chromophores, and possible assignments of these bands to one or the other of the two types of chromophore are proposed.

Animals↗
PubMed1982

Unusual emission properties of the tryptophans at the surface of short ragweed allergen Ra5.

The fluorescence and low-temperature phosphorescence of short ragweed pollen allergen Ra5 have been examined. Both the fluorescence of Ra5 in aqueous solution at room temperature and the phosphorescence of Ra5 in rigid glycol-water solvents at low temperature result entirely from the tryptophan residues in the molecule. The heterogeneity in the low-temperature phosphorescence spectra indicates that the two tryptophans in Ra5 are located in distinct environments and can be studied independently. The fluorescence wave-length maximum and large solvent-relaxation shift in the fluorescence of the allergen in 1:1 ethylene glycol-water reveal that at least one of the residues is exposed to the polar solvent. Studies of the iodide and cesium ion quenching of the fluorescence of Ra5 are consistent with this assignment but suggest that one of the tryptophans may be shielded by a negative charge in the protein. Phosphorescence data obtained in the presence of iodide and with increasing temperature confirm that both aromatic residues are readily subject to perturbation but identify the more susceptible one with one of the two spectral components that manifest themselves in the phosphorescence of Ra5. The phosphorescence wavelength maxima and the triplet-state lifetimes of the distinct tryptophans reveal that both residues lie in unusual local environment at the protein surface. While one aromatic side chain appears to be stabilized by an intramolecular interaction with a polar function, the other is perturbed quite possibly through an interaction with a disulfide linkage in the molecule.

Allergens↗