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Biomedical subjects

J D Williams

Publications and source records attributed to J D Williams.

At least 343 records · Page 19Linked to original sources
PubMed1983

Suppressor cell numbers and activity in non-transfused renal dialysis patients.

Suppressor cell activity was studied in 30-non-transfused renal dialysis patients using the Concanavalin A enhancement method. Suppressor cell numbers were estimated in 19 patients by the T suppressor (T gamma) rosette technique and in 15 patients using a monoclonal antibody (OKT8) specific for T suppressor cells. The role of prostaglandin secreting monocytes in the observed suppression was investigated in 6 patients using the prostaglandin secreting inhibitor flurbiprofen. Both suppressor cell numbers and activity were either normal or low compared with normal healthy controls. Flurbiprofen at concentrations of 10(-4) and 10(-6) M caused a decrease in activity in both patients and normal controls. The results indicate that the increased suppressor cell activity and number reported in dialysis patients may be due to the effect of blood transfusion previously administered to the patients.

Adult↗
PubMed1983

Failure of bovine complement levels measured by radial hemolysis to correlate with tube titration.

Hemolytic complement levels in 30 duplicate samples of normal bovine sera were determined by a tube titration method (CH50) and by a radial hemolysis in gel assay. Significant correlation was not observed between the values obtained by the 2 tests. This lack of correlation could be a result of considerable error observed in values obtained for duplicate samples in the CH50 method or to the relative insensitivity of the hemolysis in gel test. The hemolytic reaction in gel was found to depend on Mg2+, thus raising questions (i) about its validity in determining total hemolytic complement or (ii) about bovine C1q depending on Mg2+ rather than Ca2+ for binding to immune complexes.

Animals↗
PubMed1983

Activity of cephalosporin antibiotics against Haemophilus influenzae.

Minimum inhibitory concentrations (MICs) of nine cephalosporins were determined for 90 isolates of Haemophilus influenzae including 70 amoxycillin-resistant strains. Cefotaxime was the most active of the parenteral antibiotics tested, with a modal MIC of 0.03 mg/l, compared with ceftazidime 0.12 mg/l, cefamandole 0.25 mg/l, cefuroxime 0.5 mg/l and cefathiamidine 4 mg/l. Cefaclor was the most active of the oral cephalosporins tested, with a modal MIC of 2 mg/l compared with cephalexin 8 mg/l and cephradine 32 mg/l. Amoxycillin-sensitive and beta-lactamase-producing haemophili had similar MICs for all cephalosporins. Twenty amoxycillin-resistant beta-lactamase non-producing strains showed high MICs for all beta-lactams tested. A cell permeability barrier is postulated as a mechanism of resistance in these strains.

Amoxicillin↗
PubMed1982

Increase in antibiotic resistance in Haemophilus influenzae in the United Kingdom since 1977: report of study group.

A survey of antibiotic resistance in Haemophilus influenzae was carried out in the United Kingdom with 25 laboratories participating. The incidence of resistance in the 1841 strains examined was: tetracycline 3.1%, ampicillin 6.2%, chloramphenicol 1.03%, trimethoprim 1.4%, and sulphamethoxazole 1.5%. Of the 115 strains resistant to ampicillin, 106 produced beta-lactamase. Seventy-nine strains were capsulate, none of which was chloramphenicol resistant, but nine produced beta-lactamase (11.4%). Comparison of these figures of antibiotic resistance with those from a similar survey performed in 1977 showed a significant increase in resistance of H influenzae to ampicillin, chloramphenicol, and trimethoprim.

Ampicillin↗
PubMed1982

Antibodies to Brucella abortus in sera from Strain 19 vaccinated and non-vaccinated cows as determined by enzyme linked immunosorbent assay and conventional serologic methods.

The sensitivity of an enzyme linked immunosorbent assay was compared with 4 other serologic methods for detecting antibodies in B. abortus vaccinated and non-vaccinated cows. Antibodies were detected by ELISA in sera from more than 93% of the culture positive cows, however, less than 55% of the infected animals were identified by any other serologic method. Similarly, antibodies were detected in 82% of the culture negative cows by the ELISA method.

Animals↗
PubMed1982

Peripheral blood lymphocytes in sarcoidosis.

Sarcoidosis is characterised by changes in the lymphocyte subpopulations of the peripheral venous blood in the majority of patients. Thymus derived lymphocytes (T cells) are low whilst Bursa derived lymphocytes (B cells) are usually normal in number. The T cell lymphopaenia is best regarded as a "switching off" of available receptors as in vitro treatment with Levamisole restores this population to normal control values. A functional subset of T cells, T suppressor cells (T gamma) are activated, in sarcoidosis, in peripheral venous blood. Sarcoid sera is characterised by two inhibiting fractions; one, of low molecular weight (60 000 daltons) inhibits E rosette formation by normal T lymphocytes and may be a product of T suppressor cells or epithelioid/macrophage cells: the other is an immune complex which is capable of activating normal T suppressor cells and the serum immune complex concentration is positively correlated with suppressor cell activation in sarcoidosis.

Adolescent↗
PubMed1982

Serum beta-2-microglobulin and angiotensin-converting enzyme activity in sarcoidosis.

Angiotensin-converting enzyme activity in sarcoidosis is regarded both as a diagnostic feature and as an index of disease activity. Increased activity of this enzyme is thought to parallel macrophage and epithelioid cell activity. Beta-2-microglobulin, a low-molecular-weight protein associated with the histocompatibility antigens, is thought to reflect activation of immunocompetent cells, particularly lymphocytes. In 132 patients with known sarcoidosis no close association was found to exist between the results of the two assays (r = 0.53). Angiotensin-converting enzyme activity was raised in 33% and beta 2-microglobulin concentrations in 63% of patients with sarcoidosis. When analysed prospectively, the results of the two assays showed no correlation in 29 patients over periods of up to 19 months. Stage, duration of disease, and corticosteroid treatment showed no significant effect on levels of either angiotensin-converting enzyme or beta 2-microglobulin. The disparity between indices of macrophage and lymphocyte activation requires further study in sarcoidosis.

Acute Disease↗
PubMed1982

Interaction of immune complexes and T suppressor cells in sarcoidosis.

Circulating immune complexes were present in half of 31 patients with sarcoidosis and raised levels were associated with low numbers of T suppressor cells (T gamma- and Fc gamma-receptor-positive lymphocytes). Incubation of T cells with trypsin restored the percentage of T gamma cells to within or above the normal range. Incubation of normal lymphocytes with sarcoid immune complexes significantly reduced the number of detectable T gamma cells. Preincubation of normal lymphocytes with circulating immune complexes significantly reduced their blastogenic response to concanavalin A. These studies suggest an interaction between immune complexes and T suppressor cells in sarcoidosis and emphasise the importance of immune complexes in modulating the immune response.

Adult↗
PubMed1982

Dose dependence of piperacillin pharmacokinetics.

Pharmacokinetics were evaluated for piperacillin given as doses of 15, 30 and 60 mg/kg body weight to 12 healthy volunteers subdivided into three groups which were each given different dosage levels. For the 15, 30 and 60 mg/kg doses, the serum half-lives were 0.8, 1.0 and 0.9 h, and the disposition phase distribution volume coefficients, delta d. beta, 0.31, 0.30, ad 0.25 l/kg. The total body clearances for the three doses normalized to 70 kg body weight were 18.53, 14.00 and 13.53 l/h for the 15, 30 and 60 mg/kg doses, respectively. The corresponding values for the total area under the curves per 1.0 g dose were 57.1, 75.0 and 79.6 micrograms/ml. The urinary elimination of the antibiotic corresponding to the antimicrobial activity of unchanged drug rose from 50.0 to 71.3% of the dose, for a dose increment of 15 to 60 mg/kg. These results document that piperacillin is subject to dose-dependent pharmacokinetics. Capacity-limited kinetics is a property shared by other ureidopenicillins.

Adult↗
PubMed1981

Relationships among fertility, scrotal circumference, seminal quality, and libido in Santa Gertrudis bulls.

Forty Santa Gertrudis bulls were used to examine relationships among scrotal circumference, seminal quality, libido, and fertility [assessed as the percent pregnant of estrous females (PE rate) and the percent pregnant of females mated (PM rate)]. These bulls were selected from 220 two year old bulls to represent variations in scrotal circumference and seminal quality. Each of the 40 bulls were exposed to 100 cyclic Santa Gertrudis heifers for a 4-day (96 hr) breeding period. The number of estrous females available to each bull varied from 12 to 27. A breeding soundness examination (BSE) was conducted on each bull approximately 45 days prior to the 4-day breeding period and immediately after the 4-day breeding period. The three components of the BSE scroe (scrotal circumference, spermatozoal abnormalities and spermatozoal motility) were not significantly correlated with PE rate or PM rate at either evaluation. There was no significant correlation between PM rate and scrotal circumference; however, each of the 4 bulls having a scrotal circumference less than 30 cm had a PM rate below 31%. Relationships between seminal quality and PM rate were unclear and differed between the two evaluations. There was a trend for bulls having poor seminal quality at the first evaluation to improve by the second evaluation. Consequently, fluctuations in seminal quality between evaluations is one possible explanation for low correlations between seminal parameters and PM rate. Libido (number mated/number in estrus x 100) was positively correlated (r = 0.44) with PE rate. Using a stepwise regression procedure, the independent variables accounting for the most variation in PE rate (dependent variable) included libido, secondary spermatozoal abnormalities, and BSE score (r(2) = 0.44). Results of this study indicate that current methods of fertility evaluation did not accurately predict the fertility of individual Santa Gertrudis bulls as measured by PE rate and PM rate during a 4 day breeding period.

Journal Article↗