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Biomedical subjects

B West

Publications and source records attributed to B West.

At least 91 records · Page 5Linked to original sources
PubMed1985

Involvement of Ca2+ in platelet-derived growth factor-induced expression of c-myc oncogene in Swiss 3T3 fibroblasts.

Addition of platelet-derived growth factor (PDGF) to quiescent cultures of Swiss 3T3 fibroblasts rapidly increased the cytoplasmic free Ca2+ concentrations and afterwards the c-myc mRNA levels. The concentrations of PDGF needed for both reactions were roughly the same. Moreover, the Ca2+ ionophores, A23187 and ionomycin, mimicked the actions of PDGF and increased the c-myc mRNA levels. These results suggest that Ca2+ may be involved in the regulation of PDGF-induced expression of the c-myc gene.

Animals↗
PubMed1985

Efficacy of clavulanate-potentiated amoxycillin in experimental and clinical skin infections.

The efficacy of clavulanate-potentiated amoxycillin was compared with amoxycillin alone in experimental staphylococcal infection in dogs and in a controlled trial in clinical cases of skin infection in dogs and cats. The experimental infection was produced by subdermal inoculation with beta-lactamase producing (amoxycillin resistant) staphylococci absorbed in cotton dust. This produced discrete, localised lesions with no systemic involvement. In a cross over study, six animals were randomly allocated to treatment with either amoxycillin alone (10 mg/kg, dosed twice daily) or a formulation of clavulanate-potentiated amoxycillin (12.5 mg/kg, of a 1:4 ratio, dosed twice daily). The lesions of the animals treated with clavulanate-potentiated amoxycillin resolved more quickly than those treated with amoxycillin alone. The difference was significant (P less than 0.05) for both lesion diameter and inflammation score after day 6 of treatment. A trial was carried out in clinical cases of skin disease which were randomly allocated to twice daily treatment with either amoxycillin alone (10 or 20 mg/kg), or with clavulanate-potentiated amoxycillin (12.5 or 25 mg/kg of a 1:4 ratio). The required duration of treatment was shorter (P less than 0.5) for the potentiated amoxycillin treatments, and the success rate (judged by cure or substantial improvement) was higher (P less than 0.05) for this group, especially (P less than 0.01) where amoxycillin resistant organisms were isolated. It was concluded that clavulanate-potentiated amoxycillin was an effective treatment of skin infections both under experimental and clinical conditions.

Amoxicillin↗
PubMed1985

Mechanistic implications of the induction of thermotolerance in Chinese hamster cells by organic solvents.

Several organic solvents were shown to induce thermotolerance. These included: aliphatic alcohols (ethanol to octanol); local anesthetics; dimethyl sulfoxide; and dimethyl formamide. The minimum concentrations of the various alcohols required to induce tolerance were similar to the threshold doses for cytotoxicity. When only intramembrane concentrations were considered (by multiplying by the appropriate membrane:buffer partition coefficient), then the alcohols' threshold dose to induce tolerance was only mildly a function of carbon number. The efficiency increased almost linearly with a membrane dose from propanol to pentanol, but was slightly reduced for octanol. All alcohols induced tolerance rapidly (within a few hours after 30-min exposure), but the thermotolerance ratio decreased with increasing carbon number. Of the three anesthetics examined, lidocaine was a highly efficient inducer, procaine less so, and tetracaine did not induce tolerance even at a concentration mildly cytotoxic. Dimethyl sulfoxide and dimethyl formamide induced tolerance without cytotoxicity, but the kinetics of doing so was different from that seen with the other solvents. Only cells exposed to these water-soluble agents for 18 h or longer showed evidence of induced heat resistance. Our results indicate that membranes likely are the site for the initiation of solvent-induced cell killing and thermotolerance. The minimum dose of induction may be related to the degree of disorder induced by the individual alcohol, but the amount of tolerance induced is inversely related to this. The data on the effects of local anesthetics show that neither their common functional mode of inhibiting nerve transmission nor their similar level of cytotoxicity insures similar efficiency as tolerance inducers. Results with dimethyl sulfoxide and dimethyl formamide suggest that tolerance can be induced by more than one mechanism, or alternately, that a multiple-step mechanism can be activated at different points along this pathway. We also measured heat shock protein synthesis after several treatments; efficient inducers of thermotolerance also induced these proteins.

Alcohols↗
PubMed1984

Midface position after LeFort III advancement.

Nineteen of 30 patients who had midface advancement procedures between 1972 and 1980 had sufficient cephalometric data to be included in this retrospective study. The position of the midface in relation to the cranium and mandible was evaluated immediately postoperatively and for a period of 2 to 11 years (mean 5.8 years). At 1 year, midface position after LeFort III advancement was stable in 12 of 19 patients. Of these 12 patients, 8 showed some evidence of downward and/or forward movement of the midface. The remaining 7 patients showed a minor degree of midface relapse in the first year of follow-up. In 15 of 19 patients, at 2 years or more postoperatively, the final position of the midface was either at, anterior to, or inferior to its immediate postoperative location. Correction of exorbitism remained stable in all but one patient, who required a second advancement of the orbital segment. Three patients required subsequent LeFort I osteotomy to correct class III occlusion. Prognathism was determined to be secondary to mandibular growth, not midface relapse.

Adolescent↗
PubMed1984

Mycobacterium bovis infection in primates in Dublin Zoo: epidemiological aspects and implications for management.

An outbreak of tuberculosis in non-human primates was successfully contained in the isolation area of Dublin Zoo. A Mayotte lemur, a lion-tailed macaque, a Patas monkey and a Siamang gibbon developed tuberculosis, and Mycobacterium bovis was isolated from all but the lemur, from which lesions were not cultured. Procedures for the prevention of tuberculosis in primate collections and for the management of outbreaks are discussed. The need for typing of the isolated pathogen is emphasized.

Animals↗
PubMed1981

Appraisal of the suitability of a disease model of acute salmonellosis in calves for chemotherapeutic studies.

When young calves were dosed orally with 10(10) organisms of a culture of Salmonella dublin, typical symptoms of acute salmonellosis followed with a death rate of 86 per cent. Peak mortality occurred six days after infection. As a result of a statistical appraisal of the consistency of mortality in groups of untreated calves a model is proposed for the therapeutic evaluation of antibacterial compounds, which compares the number of survivors in groups of seven or eight calves with a minimum of four needed for significant indication of efficacy. Bacteriological and pathological investigations showed that the experimental disease was initially an acute systemic infection followed by severe enteritis. Measurements of plasma concentrations of enzymes and other constituents did not achieve the desired objective of establishing a method of quantitative evaluation of the clinical status of individual animals, although some changes occurred which were consistent with the pathology of the disease and suggested possible mechanisms by which jaundice occurred.

Acute Disease↗
PubMed1980

Effect of pulsed high frequency electromagnetic radiation on embryonic mouse palate in vitro.

Palatal shelves from 14-day-old embryonic mice were exposed to a 27.12 MHz pulsed non-ionizing radiofrequency (Diapulse) for 20 min followed by 24-hour organ culture in nutrient agar. Diapulse-treated palatal shelves showed induction of cartilage within the mesenchymal compartment and loss of the overlying epithelium in contrast to controls which were free of cartilage. The results are thought to be independent of thermal changes and may be due to calcium flux within the tissue.

Animals↗
PubMed1979

Effects of concurrent sepsis with clinically significant pulmonary embolic disease.

Forty-one patients with significant pulmonary emboli were reviewed. The presence of heart disease and obesity was found with relatively constant frequency throughout the groups presented. Postoperative infections (wounds or abscess) were frequently associated with fatal or significant pulmonary embolism, particularly after abdominal and pelvic operations. The infection rate (65 per cent) in patients in whom significant pulmonary embolism developed after abdominal and pelvic operations is particularly striking when compared to the overall infection rate of 7 per cent for major operations in our hospital. Recent studies of prophylactic minidose heparinization reveal an increased number of complications due to the heparin [24], and thus the proper selection of cases for prophylactic minidose heparin is mandatory. The data suggest that patients at high risk for the development of postoperative complications of infection are also at high risk for the development of significant pulmonary emboli and should be considered candidates for prophylactic minidose heparinization.

Adult↗
PubMed1979

A survey of trimethoprim resistance in the enteric bacterial flora of farm animals.

For 29 months the Veterinary Investigation Centres, covering the whole of Great Britain, forwarded trimethoprim-resistant gram negative enteric bacteria to the Wellcome Research Laboratories. These were examined for degree of resistance, presence and type of R factors. Trimethoprim resistance was found in 0.6% of the total number of strains examined by the Veterinary Investigation Centres. Trimethoprim R factors were demonstrated in one quarter of the resistant strains, and R factors were found in two strains of Salmonella typhimurium. It was concluded that while the incidence of trimethoprim resistance revealed by the survey gave no cause for alarm, the detection of resistant strains, and particularly R factors, indicated that the drug should continue to be used only for specific therapeutic purposes.

Animals↗
PubMed1979

A serological survey of St Lucia.

A serological survey of a random sample of 541 of the population of St Lucia was undertaken. The prevalence of antibodies to dengue, herpes virus, VZ, rotavirus, rubella and syphilis is described and compared with other communities.

Adolescent↗
PubMed1979

Antipsychotic drugs inhibit prolactin release from rat anterior pituitary cells in culture by a mechanism not involving the dopamine receptor.

Bromocriptine, a dopamine agonist, inhibited secretion of PRL and did not affect GH release from rat anterior pituitary cells in culture. The reversal of this inhibition of PRL release by butaclamol, a dopamine antagonist, was stereospecific; 10 nM d-butaclamol completely reversed the inhibition caused by 10 nM bromocriptine, while l-butaclamol had no effect at concentrations up to 10 microM. However, both enantiomers at 10 microM inhibited PRL release to 30% and GH release to 91% of control values. Two other dopamine antagonists also inhibited hormone release. Haloperidol (10 microM) inhibited PRL release to 23% of control values and did not affect GH release; 3.3 microM pimozide inhibited PRL and GH release to 18% and 38% of control values, respectively. These data indicate that, the inhibition of PRL by antipsychotic drugs is not mediated through the dopamine receptor.

Animals↗