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Biomedical subjects

A Stanton

Publications and source records attributed to A Stanton.

53 records · Page 3Linked to original sources

Clavulanate-potentiated amoxycillin: activity in vitro and bioavailability in the dog.

Clavulanic acid is an inhibitor of beta-lactamase (penicillinase) and when used with amoxycillin the resulting combination becomes active against most bacteria resistant to amoxycillin through production of beta-lactamase. A total of 551 bacterial isolates from dogs and cats were examined by disc sensitivity testing, which showed that there was amoxycillin resistance particularly among staphylococci (50 per cent), Klebsiella species (97 per cent) and Escherichia coli (28 per cent). A combination of potassium clavulanate and amoxycillin reduced the incidence of resistance to 0.3, 3 and 7 per cent, respectively. Minimum inhibitory concentrations were determined for a number of the isolates and showed marked reductions in the presence of potassium clavulanate. A formulation containing amoxycillin trihydrate and potassium clavulanate (4:1) was dosed to beagles at 12.5 mg/kg. Concentrations of the drugs in blood, tissue fluid and skin showed that both drugs were sufficiently well absorbed and distributed to allow a prediction of efficacy against infections caused by beta-lactamase producing bacteria.

Amoxicillin↗

Rapid viral diagnosis of acute respiratory infections: comparison of enzyme-linked immunosorbent assay and the immunofluorescence technique for detection of viral antigens in nasopharyngeal secretions.

Nasopharyngeal secretions from adults and children were obtained in Stockholm, Sweden, for routine diagnosis of influenza A virus, influenza B virus, respiratory syncytial (RS) virus, parainfluenza type 3 virus, and adenovirus infections by demonstration of viral antigens directly in the specimens. The cells in nasopharyngeal secretions were pelleted by centrifugation for preparation of cell deposits for diagnosis by the immunofluorescence technique (IF) in London, England, and in Stockholm, whereas the supernatants were used to diagnose infection by the enzyme-linked immunosorbent assay (ELISA) in Stockholm. Titrations of the various purified viruses showed that ELISA could detect viral antigens in amounts corresponding to 1 to 10 ng of virus protein per test well. In a series of 73 specimens tested for influenza A, RS, and parainfluenza type 3 viruses by IF in London and by ELISA in Stockholm, 15 of 18 RS, 14 of 15 influenza A, and 2 of 2 parainfluenza type 3 viral infections were diagnosed by ELISA as compared with IF, giving sensitivities for RS and influenza A viral diagnosis of 83 and 93%, respectively, and a specificity of 100%. In another series of specimens from 35 patients tested for influenza B virus and adenovirus, five influenza B virus and four adenovirus infections were diagnosed by both methods; one additional influenza B infection was detected only by IF and another only by ELISA. Comparisons of diagnostic results between the two methods performed in Stockholm gave nonagreement of results for 37 of 1,593 tests (2.5%) for the five viruses. The conclusion reached was that the described ELISA, although a satisfactory test, had somewhat less sensitivity than did IF for the detection of respiratory viral infections. This could possibly be explained by unnecessary dilutions of specimens at the time of collection; transportation, processing, and storage of specimens were less complicated than for IF.

Adenoviridae Infections↗

Absorption in calves of amoxicillin, ampicillin, and oxytetracycline given in milk replacer, water, or an oral rehydration formulation.

Oxytetracycline, amoxicillin or ampicillin suspended in milk replacer, water, or a glucose-glycine-electrolyte solution (GGES) was orally given to calves (n = 64). Oxytetracycline suspended in milk replacer gave lower relative bioavailability than when suspended in water (P less than 0.01) or in GGES (P less than 0.001). Seemingly, the 63% binding (only partly reversible) of oxytetracycline suspended in milk replacer was responsible for low serum concentrations, whereas the greater water absorption from the GGES was responsible for improved uptake of antibiotic. Amoxicillin suspended in milk replacer had a delayed absorption, compared with that suspended in water, but the relative bioavailabilities from milk replacer and water were similar. In contrast, peak serum concentration and bioavailability were higher (P less than 0.05) when amoxicillin was suspended in GGES than when suspended in water. Binding of amoxicillin with milk replacer was comparatively low (16%) and was reversible. Ampicillin suspended in GGES gave a higher peak serum concentration (P less than 0.05) than when suspended in milk replacer. It, therefore, appeared that these antibiotics were more bioavailable when suspended in GGES than when suspended in water or especially in milk replacer. Oxytetracycline was bound particularly strongly to milk replacer.

Amoxicillin↗

Learned helplessness and the detection of contingency: a direct test.

Two studies tested a basic hypothesis of the learned helplessness model: That performance deficits associated with exposure to uncontrollable outcomes are directly mediated by an individual's perception of response-outcome independence. In the first experiment 48 subjects were exposed to noise bursts. For one experimental group, the termination of the noise was response-contingent. For five other groups, noise-burst termination was independent of subjects' responses. These five groups varied in the number of trials on which they received positive feedback: As predicted, subjects over-estimated the amount of control they had over noise termination as a positive linear function of the amount of noncontingent positive feedback they received. Although subjects exposed to either noncontingent positive or negative feedback showed subsequent performance deficits on an anagrams task, the expected relation between perceived control and subsequent performance failed to emerge. These findings were replicated in a second experiment. In addition, subjects' locus, stability, and globality attributions failed to predict subsequent performance. These results call into question the central premises of helplessness theory: That perceived uncontrollability and causal attributions mediate learned helplessness.

Achievement↗

Adenosine deaminase activity in lymphoid subpopulations and leukemias.

Adenosine deaminase has been measured by the indirect spectrophotometric method in lymphoblasts from adult and pediatric lymphoblastic leukemias, peripheral T- and B-cells, mature T-cell leukemia (Sézary cell), and mitogen-stimulated peripheral control T- and B-cells. It was found that, if the specific activity of the enzyme is expressed in terms of cell cytoplasmic protein concentration rather than cell number, null-cell leukemia has enzyme levels markedly higher than T-cell lymphoblastic leukemic or Sézary cells. The range in values is far less than those reported by other authors using the direct spectrophotometric assay and cell number prior to lysis. Non-leukemic T- and B-cells from control individuals show minor differences as do T gamma-enriched cells. Lymphocytes from female oriental control populations were significantly lower. Both mitogen-stimulated lymphoblasts and control lymphocytes show similar elevations in adenosine deaminase activity so that no effect per se can be ascribed to lymphoblastic transformation.

Adenosine Deaminase↗

Collaboration in nursing education.

The process of development of a collaborative link between the United Midlands College for Nursing and Midwifery and Coventry Polytechnic is described. The process, which began early in 1990, has already brought benefits for the staff and students of both institutions. Evaluation of the arrangement will be ongoing, and will take into account national and regional developments in funding and organising nursing and midwifery education.

Education, Nursing↗