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Biomedical subjects

D Cook

Publications and source records attributed to D Cook.

252 records · Page 14Linked to original sources
PubMedDate not supplied

Changes in vasoactive properties of blood products with time and attempted identification of the spasmogens.

The contractile activity of various fresh, or incubated blood fractions was studied in vitro using the isolated canine basilar artery. Significantly greater contraction was induced by fresh platelet rich plasma (PRP) and serum compared to red blood cells (RBC). Following incubation, the contractile activity of RBC increased, reaching a plateau at day-3 and it was maintained for at least 14 days, while both PRP and serum lost most of their activity after 24 h of incubation. The contractions induced by fresh blood fractions were only partially blocked by desensitization of 5-hydroxytryptamine (5-HT) receptors or by the 5-HT antagonist methysergide. D-600 effectively antagonized the response to all blood fractions. Biochemical analysis of the incubated RBC by means of Sephacryl S-200 column chromatography and SDS-urea polyacrylamide gel electrophoresis revealed that the contractile substance possessed a molecular weight of about 60,000 daltons. Vasoactivity was only present in one peak of the chromatographically eluted fractions which was shown to possess a similar absorption spectrum to that of hemoglobin. Hemoglobin concentration was highest in day 3, 7, and 14 fractions and may be correlated with the contractile activity of incubated samples.

Animals↗
PubMedDate not supplied

Indications, technique, and complications of balloon tamponade for variceal gastrointestinal bleeding.

Timely treatment of bleeding esophageal varices with balloon tamponade effectively achieves initial hemostatis. However, therapeutic endoscopy and sclerotherapy in patients with acute upper gastrointestinal hemorrhage is associated with better short- and long-term follow-up. We describe the technique of esophagogastric balloon insertion, as well as principles of monitoring and maintenance. The different types of balloons for tamponade are described, as well as potential complications.

Balloon Occlusion↗
PubMedDate not supplied

Quantitative evaluation of sympathetic and parasympathetic control of iris function.

The use of quantitative measurements of pupil size as an index of autonomic nervous system (ANS) activity in normal and diabetic subjects is described. The dual innervation of the iris by the parasympathetic (PNS) and sympathetic (SNS) nervous system was demonstrated by measurement of steady-state pupil size before and after changes in ANS activity by pharmacologic agents. In the presence of total PNS blockade, dark-adapted pupil size was a reliable index of SNS activity to the iris. Latency time (time from light stimulation to initial pupil response) appeared to be a good index of PNS activity. However, increased SNS activity may also prolong the latency time. Thus, consideration of SNS activity is necessary when evaluating the latency time. In 25 diabetic subjects, there was evidence of impaired SNS activity (smaller dark-adapted pupil size during total PNS blockade) and PNS activity (prolonged latency time). In a subgroup of diabetic subjects without clinical manifestations of autonomic neuropathy and normal subjects, both dark-adapted pupil size during PNS blockade (SNS index) and latency time (PNS index) were abnormal. The coefficient of variation for these two indices was less than 5% in glycemic stable diabetic subjects. Thus, these two indices are reliable and sensitive measures of the SNS and PNS activity to the iris in normal and diabetic subjects.

Adult↗
PubMedDate not supplied

Non-nominal HIV surveillance: preserving privacy while tracking an epidemic.

OBJECTIVE: To enhance HIV surveillance within a non-nominal provincial testing system. METHODS: Confirmatory HIV tests from a provincial laboratory were analyzed during 1995 and 1996. Enhancements included elimination of repeat positive tests for the same individual using automated matching of non-nominal identifiers and nurse call-back of health care providers, completion of missing information through call-back and connection of providers with resources for patient care. RESULTS: Forty-seven percent of 2,683 reactive HIV tests were identified as duplicates for the same individual, meaning that 1,401 people tested positive for the first time. From laboratory test data to enhanced unduplicated data after call-back, the proportion of tests for which risk and ethnic information was unknown dropped from 37% to 11% and from 64% to 18% respectively (p < 0.0001). CONCLUSIONS: Enhanced non-nominal surveillance for HIV is a practical means of marrying the needs of public health for epidemiological information and the rights of patients to privacy.

AIDS Serodiagnosis↗
PubMedDate not supplied

Determinants of HIV-related high risk behaviours among young offenders: a window of opportunity.

PURPOSE: To study HIV-associated risk behaviours among young offenders. METHODS: Juveniles aged 12 to 19 years entering correctional facilities in British Columbia volunteered in an unlinked anonymous study. Logistic regression was used to identify factors associated with high-risk sexual behaviours and injection drug use (IDU). RESULTS: Despite low HIV prevalence (0.25%), patterns of risk behaviour were evident. IDU and homosexual/bisexual activity were equally prevalent among youth aged 12 to 15 and 16 to 19 years. For both age groups, IDU and female gender were significant predictors of sex for trade and sex with another drug user. Natives aged 12 to 15 years were five times more likely to inject drugs than non-Natives. However, predictors of IDU differed for older vs. younger youth. CONCLUSIONS: Patterns of high-risk activity begin early and selective pressures may differ for younger vs. older young offenders. Youth in detention provide a window of opportunity for enhanced HIV/AIDS education.

AIDS Serodiagnosis↗