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Biomedical subjects

C Graham

Publications and source records attributed to C Graham.

At least 127 records · Page 7Linked to original sources

Bovine serum eliminates rapid nonspecific toxic reactions during bioassay of stored fish for Clostridium botulinum toxin.

When stored fish or some fish products were tested for the presence of Clostridium botulinum toxin, nonspecific toxic reactions in mice often occurred, rendering the bioassay inconclusive. The nonspecific toxic reactions were mediated by the gram-negative microbiota, inherent to the fish, which were the source of lethal, heat-stable endotoxins. The treatment of assay samples with bovine serum eliminated nonspecific reactions through the interaction of constituent serum immunoglobulin M (IgM) with endotoxic material. Removal of IgM from bovine serum through treatment with protein A or concanavalin A resulted in a loss of protective activity.

Animals↗

A comparison of tomato (Lycopersicon esculentum) lectin with its deglycosylated derivative.

A deglycosylated derivative of tomato (Lycopersicon esculentum) lectin was prepared with the use of trifluoromethanesulphonic acid. Its properties were generally similar to those of the native lectin, but differences were evident in terms of relative agglutinating activity towards sheep, (untreated) human and trypsin-treated human erythrocytes. The two forms of tomato lectin were used in conjunction with a battery of specific antisera to investigate structural relatedness among solanaceous lectins. Immunological cross-reactivity between tomato, potato and Datura lectins depends on the integrity of the glycosylated region of those lectins; that between Datura lectin and other seed lectins, however, has a separate structural basis.

Cross Reactions↗

Solubilization studies on the epicuticular antigens of Strongyloides ratti.

Antigens on the epicuticular surface of Strongyloides ratti infective third-stage larvae (L3) were demonstrated by both ferritin-conjugated antibody and indirect fluorescent antibody techniques. The rat antibodies from immune serum that bind to these antigens were chiefly of the IgG2a subclass. Solubilization of these antigens by extraction with detergents, hypertonic salt, organic solvents and by freezing and thawing was limited as measured by the reduction in antibody binding to the epicuticle. The epicuticular antigens were resistant in situ to degradation by a variety of proteases, carbohydrases and lipase. Infectivity of the L3 in the rat was not reduced by prior sensitization with rat antibody. The epicuticular antigens are not completely species-specific since antibody from S. ransomi-infected pigs cross-reacted well with S. ratti L3 antibody. However, high levels of resistance to S. ratti could be induced in rats only by multiple inoculations of heat-killed S. ratti L3.

Animals↗

Trazodone--a new assay procedure and some pharmacokinetic parameters.

1 A simple and specific procedure is described for the determination of the new anti-depressant trazodone in human plasma utilising reverse-phase HPLC which is sensitive to 20 ng ml-1. 2 Following oral administration of single 50 mg doses of two formulations of trazodone on separate occasions to healthy fasted volunteers, the peak plasma concentration, time to peak concentration, area under the curve, elimination rate constant and half-life were determined. 3 The two formulations are closely similar and they are considered to have comparable bioavailability.

Biological Availability↗

Fatalities on the liquid-protein diet: an analysis of possible causes.

Reports of deaths occurring in patients using variants of the liquid-protein diet (LPD) have raised some questions about the safety of this procedure for the management of obesity. Case reports involving 44 publicized deaths were reviewed. Possible causes of death including such factors as potassium and/or electrolyte deficiencies, inadequate or poor quality protein, imperfect patient selection or compliance, an associated medications or disease were examined. Data in eight patients are insufficient for analysis or show that the patients were not using a LPD. Of the remaining 36 patients 32 were inappropriately managed as judged by conservative standards. Four patients who may have been properly managed all had known preexisting cardiac disease. The analysis does not identify any single factor which is responsible for the deaths. It shows that the procedure was widely misused and suggests that this contributed in multiple ways to the fatalities. No properly managed patient died as a direct result of the LPD and the cardiac deaths could not be ascribed to the LPD. Since the LPD, when properly supervised, has demonstrated great promise in the management of obesity, it is suggested that caution be exercised in dismissing the LPD because of adverse publicity.

Adult↗

Epidural analgesia and cardiac output in severe pre-eclamptics.

Labour and delivery cardiac output was assessed by thermal dilution in ten severe pre-eclamptics who received lumbar epidural analgesia. Control cardiac output was 8.8 litres/min which remained statistically unchanged following administration of lumbar epidural analgesia. At birth and delivery of the placenta, there was a moderate increase in cardiac output which increased significantly (28%) by 15 min after delivery of the placenta. Subsequently over the next hour, cardiac output returned toward baseline levels. Mother and fetus were stable throughout and infant Apgar scores were good. These results emphasise that lumbar epidural analgesia has little effect on cardiac output in severe pre-eclamptics.

Adolescent↗

Conservation of human research teeth by controlling cavity depth.

In order for the dental profession to obtain reliable data as to whether new or experimental restorative materials and adjunct agents are more or less irritating to pulp tissues than dental products currently in use, pulp studies at the national and international level are being standardized to enhance corroboration. The purpose of this study was to reduce the number of human teeth required in any experimental pulp toxicity study by controlling the problem of cavity depth. Many valuable teeth are wasted by making cavity preparations that are either too shallow or too deep, with consequent pulp exposures. This needs to be corrected.

Dental Cavity Preparation↗