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Biomedical subjects

R C Graham

Publications and source records attributed to R C Graham.

64 records · Page 4Linked to original sources
PubMed1967

Metabolic and morphological observations on the effect of surface-active agents of leukocytes.

Morphological and metabolic observations have been made on the effects of endotoxin, deoxycholate, and digitonin (at less than 50 microg/ml) on polymorphonuclear leukocytes and mononuclear cells. The agents stimulate the respiration and glucose oxidation of these cells in a manner similar to that seen during phagocytosis. Electron microscopy revealed no morphological changes with the first two agents, but dramatic membrane changes were seen in the case of digitonin. Here tubular projections of characteristic size and shape formed on and split off the membrane. All the agents stimulated uptake of inulin, but efforts to demonstrate increased pinocytosis by electron microscopy have not so far succeeded, probably due to limitations in present experimental techniques.

Animals↗
PubMed1966

Glomerular permeability. Ultrastructural cytochemical studies using peroxidases as protein tracers.

1. Glomerular permeability was studied by ultrastructural cytochemistry, using as protein tracers two intravenously injected peroxidases of differing molecular weight. 2. Horseradish peroxidase (molecular weight 40,000) passed rapidly through the endothelial fenestrae, across the basement membrane, and through the epithelial slits into the urinary space. Human myeloperoxidase (molecular weight 160,000 to 180,000) also passed rapidly through the endothelial fenestrae and across the basement membrane, but was impeded at the level of the epithelial slits. Both proteins were taken up in large amounts by the mesangial cells. 3. The present findings indicate that the epithelial slits are the primary filtration barrier responsible for the differential permeability to proteins of varying molecular size. 4. The observations also support the concept that an important function of the mesangial cells is the incorporation and disposal of glomerular filtration residues.

Animals↗
PubMedDate not supplied

Young Investigator Award. In vivo treatment of infected prosthetic graft material with urokinase: an animal model.

PURPOSE: Pyogenic infection of vascular grafts represents a serious complication that may necessitate graft removal. If better treatment methods could be developed, perhaps some infected grafts could be salvaged and not removed. This study reports an animal model that evaluates the sterilization of contaminated vascular graft material implants with urokinase and antibiotics. MATERIALS AND METHODS: Polytetrafluoroethylene (PTFE) implants were incubated overnight in a known concentration of bacteria (Staphylococcus epidermidis) and were then implanted subcutaneously into four groups of anesthetized hamsters. The first group (control) received no treatment. The second group received urokinase injections twice daily into each abscess. The third group received intraabscess urokinase and systemic gentamicin twice daily. The fourth group received only systemic gentamicin. The hamsters were killed after 1 week. The graft implants and surrounding tissues were excised and submitted for quantitative cultures. RESULTS: With use of a cutoff value of 100 organisms per milliliter, below which the abscesses were considered noninfected, the following rates of noninfectivity were observed: group 1 (control), 5% noninfected; group 2 (urokinase only), 19.4%; group 3 (urokinase and gentamicin), 63.2%; and group 4 (gentamicin only), 32.5%. The noninfectivity rate of group 3 was significantly higher than that of all other groups combined (P < .001) and was significantly better than that of group 4 alone (P = .013). CONCLUSION: The combination of intraabscess urokinase and systemic gentamicin is very synergistic in graft sterilization. Urokinase may assist in the degradation of both fibrin and the biofilm produced by S epidermidis, thus improving penetration of antibiotics and local host defense mechanisms.

Abscess↗
PubMedDate not supplied

Health professionals' perspectives in exercise referral: implications for the referral process.

The number of exercise referral schemes expanded rapidly across the UK during the 1990s. Health professionals are thought to be one of the most credible sources of health advice for patients and, hence, are thought to have a pivotal role to play in exercise referral schemes. The aim of the study was to investigate the exercise referral process from the health professional's perspective, specifically examining perceived barriers to referral, priority given to an exercise referral scheme in day-to-day consultations, perceived importance of their role in the process and referring practices. Quantitative and qualitative research methods were utilized with 49% (n = 71) of general practitioners and practice nurses (collectively referred to as health professionals throughout), in a large North West borough (population size approximately 287,000) responding to a postal survey and 11 health professionals (general practitioners n = 9 and practice nurses n = 2) volunteering to take part in a semi-structured interview. Barriers to the referral of patients included lack of time, lack of feedback regarding the patients referred, medico-legal responsibility, a feeling that patients may not take exercise advice given and the belief that physical activity promotion is not a priority during routine consultations. Health professionals refer individuals to an exercise referral scheme on an unsystematic basis and express mixed opinions regarding their perceived role in patient physical activity behaviour change. This study calls for closer partnership working, involving training for promoting physical activity in general practice. Also, greater feedback with regard to patient benefits is needed, in order to overcome some of the practical and perceived barriers for health professionals when referring patients to an exercise referral scheme.

Attitude of Health Personnel↗