Biomedical subjects
Publications and source records attributed to J S Kennedy.
Advances in laparoscopic surgical procedures will be facilitated by the ability to perform suturing efficiently and effectively. A simple technique of extracorporeal suturing is described, which permits rapid and reliable knot placement for a wide variety of laparoscopic procedures.
The relationship between self-reports of caffeine ingestion on two occasions and measured plasma concentrations of caffeine and its major metabolites was examined. A subject population [25 men and 25 women, age 20-45 years (mean: 28.7 yr)] that was enrolled in a benzodiazepine pharmacokinetic study underwent general medical screening on two occasions, each including detailed caffeine histories. Before beginning their scheduled study, plasma samples were obtained and evaluated by HPLC for caffeine, paraxanthine, theophylline, and theobromine. These values were compared with estimates of caffeine consumption in mg/day generated from both histories. There was no significant difference between plasma levels of caffeine, metabolites, or caffeine plus metabolites for categories corresponding to reports of low, intermediate or high caffeine use. A self-reported caffeine consumption of greater than 300 mg/day (high) did correlate, however, with a significant smoking history. The authors conclude that self-reports of caffeine ingestion do not accurately reflect acute exposure, and that if caffeine use is of importance in a given setting, reports should be confirmed by biochemical means.
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In consideration of the pulsatile blood flow in a conduit, the constitutive equation for the whole human blood of F. J. Walburn and D. J. Schneck (Biorheology, Vol. 13, 1976, pp. 201-210) is utilized. Governing equations are solved numerically yielding the velocity and the shear stress distributions. These results are discussed and compared with the Newtonian fluid, Casson's fluid, and Bingham fluid applications.
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It is shown analytically and experimentally that, within the scope of a surgery, the effects of variations in the position of the transplant-aorta contact point (relative to the renal artery natural location), in the transplant departure angle (relative to the aorta), in the transplant length and in the transplant curvature are relatively insignificant regarding mean flow resistance. Hence, it is concluded that, from this point of view, it is not important how the transplant will be situated and that the space convenience should be the surgical determining factor. Nevertheless, it is also shown that the rate of blood flow to the kidney may be significantly curtailed if the selected transplant diameter is too small. However, it is indicated that the above may not constitute the only criterion. Since there exists a theory that the atherosclerotic formations begin and develop within the separation regions, additional research is suggested correlating separation regions with the variables indicated above.
The presenting problems and pre-admission diagnoses of 100 consecutive admissions to a geriatric psychiatry inpatient assessment unit were assessed in a retrospective survey and the use of psychotropic medication examined. Although post-admission diagnoses showed a high proportion of depressive illness amongst the patients, depression was infrequently diagnosed prior to admission and antidepressants infrequently used. The majority of these elderly patients were referred with a diagnosis of dementia and 'behaviour problems'. These were treated prior to admission with neuroleptics or benzodiazepines in line with prescribing habits in this population reported elsewhere in North America. Attention is drawn to the significant incidence of major depression in these patients and the excellent response to treatment, both with chemotherapy or with electrotherapy. Attention is also drawn to the pre-admission prescribing of psychotropic drugs which are likely to lead to problems when used in the elderly and likely to result in significant iatrogenic disorders.
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A 2-year-old girl being prepared for a bone marrow transplant for treatment of stage IV neuroblastoma suffered a fatal graft v host (GVH) reaction following a transfusion on nonirradiated packed RBC. GVH disease is a recognized complication of transfusion in patients with leukemia and lymphoma and is a frequent complication following bone marrow transplantation. GVH disease has also been reported in pediatric patients with solid tumors who have received sufficient chemotherapy to render them immunocompromised. GVH disease can be prevented by irradiating all blood products with at least 1,500 rad for patients having total lymphocyte counts less than 1,000/microL or for those who have received greater than 30 mg/kg/d of Cytoxan.
Using an indirect immunoperoxidase staining technique we have demonstrated the plasma protein, prealbumin, in the cells of the pancreatic islets of Langerhans. Serial sections stained with antisera to glucagon, insulin and somatostatin revealed that the distribution of the prealbumin stained cells matched that of the glucagon A-cells. Absorption and cross-absorption experiments with prealbumin and glucagon showed that the staining was specific. We also found positive staining for prealbumin in single cells in the mucosa of the gastrointestinal tract, mainly stomach and colon, and kidney tubules.
The aortic arch has, on average, an angle of twist of 15 degrees. The purpose of the research conducted was to ascertain if this twist angle has any effect on the flow field of the aortic arch and the distribution of the flow amongst the branches. It was found that the blood flow distribution is practically independent of the angle of twist of the aortic arch. However, the destination of a fluid particle located at a specific point in the cross-section at the entrance to the aortic arch does depend on the angle of twist.
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Steady flow within a uniform circular curved tube formed by two 90-deg elbows was studied as a function of psi, the angle between the planes of curvature of the two elbows. Boundary layer separation was found at two locations. The sites of these separation zones were observed to be essentially independent of psi while the Reynolds number at which separation was first detected was found to decrease as psi increased. The relation between separation and the pathogenesis of atherosclerosis is discussed. Secondary flow pattern was found to depend on psi and in some instances on Reynolds number as well.
Thirty-five golden hamsters infected with Leishmania donovani were treated with Pentostam and followed up to determine the effect of treatment on the development of secondary amyloidosis. Seventy untreated golden hamsters infected with L. donovani were followed up as controls to determine the pattern of development of secondary amyloidosis. Amyloid developed in all animals treated and untreated. The treatment significantly prolonged the survival time, but did not inhibit the development of renal amyloid in animals shown by biopsy to be free from renal amyloid at the time of treatment. When amyloid was present in kidney at the time of treatment it progressed invariably to renal failure.
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The effects on pituitary-thyroid function of the commonly prescribed anti-bacterial preparations co-trimoxazole and co-trifamole, and their component drugs, have been studied in the rat and compared to the changes caused by propylthiouracil. Co-trimoxazole and co-trifamole, in doses 20-fold in excess of a pharmacological dose administered for 10 days, produced marked changes in hormone levels consistent with blocking of hyperplastic goitre formation, were also demonstrated. Propylthiouracil produced less marked changes of thyroid hormone levels but higher levels of thyroid-stimulating hormone. Pharmacological doses of co-trimoxazole and co-trifamole and sulphamoxole, the sulphonamide component of co-trifamole, caused significant changes in thyroid hormone levels consistent with anti-thyroidal activity. In contrast, there was no evidence that trimethoprim, which is common to both preparations, or sulphamethoxazole, the sulphonamide component of co-trimoxazole, had an anti-thyroidal action, indeed, serum thyroxine levels were significantly increased at pharmacological dosage. We have concluded that the new commonly prescribed combination preparations retain the goitrogenic properties of the earlier sulphonamides.
A 52-year-old woman presented with a laryngeal sarcoma eight years after receiving two doses, each of 30 mCi, of iodine-125 for thyrotoxicosis. That extrathyroidal tissue receives a higher radiation dose of low-energy photon radiation from iodine-125 than from an equivalent microcurie dose of iodine-131 and that the tumour was of a type which rarely arises spontaneously in the larynx suggest a possible link between the development of the tumour and iodine-125 therapy.