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Biomedical subjects

R Long

Publications and source records attributed to R Long.

At least 145 records · Page 8Linked to original sources

Management of uremic pericarditis: a report of 11 patients with cardiac tamponade and a review of the literature.

Uremic pericarditis remains a significant cause of morbidity and mortality in most hemodialysis programs. A review of the literature and out own experience show that uremic pericarditis should be vigorously treated when detected. Usually an increase in the dialysis program with regional heparinization is sufficient to control the pericarditis. When signs of pericardial effusion are manifested, patients often progress rapidly to cardiac tamponade. A surgical anterolateral pericardiectomy is the most satisfactory measure in controlling pericardial effusion and preventing fatal cardiac tamponade. Although these patients have severely impaired renal function, the operation can be performed safely with a low morbidity and mortality.

Adolescent↗

Pericardiectomy for uremic tamponade.

Pericardial tamponade developed in 29 patients with uremia. The clinical presentation varied, some patients having no symptoms whereas others sustained circulatory collapse. Pericardial friction rub, elevated central venous pressure and a paradoxical pulse were the most common physical findings. Serial chest radiography and echocardiography were most useful procedures in confirming this diagnosis. Two patients were treated conservatively and died despite repeated pericardiocentesis. The remaining 27 patients underwent partial pericardiectomy. One patient died of cardiorespiratory failure and a second from brain damage related to cardiac arrest before pericardiectomy. The other 25 patients reported immediate relief of symptoms and no recurrence of pericarditis. Pericardiectomy is the treatment of choice in uremic pericardial tamponade.

Adolescent↗

Separation of sperm through a 12-layer percoll column decreases the percentage of sperm staining with quinacrine.

Previous methods of enriching sperm with a higher percentage of Y-bearing sperm have been questioned because the claims that Y enrichment was present were based on quinacrine staining of the Y chromosome, and the enrichment was not confirmed by polymerase chain reaction (PCR) or fluorescent in situ hybridization (FISH) techniques. A technique was evaluated that theoretically could increase the percentage of X-bearing sperm by isolating a fraction of the "heaviest" sperm by passing them through 12 layers of discontinuous Percoll gradient. Initially 12 specimens were checked both before and then after separation with 12 layers of Percoll for percentage of Y sperm. The median for baseline Y percentage was 49% and after processing the percentage of Y dropped to 10%. An additional 19 specimens were checked after separation only. The median was 19%. The sample with the lowest preseparation % of quinacrine staining sperm was 45% and the highest was 54%. After 12-layer Percoll, the lowest percentage was 3% and the highest was 24%. There have been claims that quinacrine staining can falsely increase apparent Y-bearing sperm enrichment following certain separation procedures, e.g.. albumin separation, by nonspecific staining of autosomal chromosomes. If anything, then, it should falsely decrease X-bearing sperm enrichment. Thus, 12-layer Percoll separation may actually enrich for X-bearing sperm or possibly this procedure somehow nonspecifically inhibits the ability of quinacrine to stain the Y chromosome.

Cell Separation↗

Treatment of sperm with subnormal host scores with chymotrypsin/viable pregnancy after IUI.

Men with low hypoosmotic swelling test (HOST) scores (<50%) rarely achieve a pregnancy with intercourse or conventional intrauterine insemination (IUI) or even IVF. The defect seems to be related to a toxic factor attached to the sperm that can be transferred to the zona pellucida, which ultimately interferes with implantation. A small case series showed optimistic pregnancy outcome with treatment of the sperm with low HOST scores with chymotrypsin. However, the live pregnancy rate in 90 subsequent IUI cycles in men whose low HOST scores were improved by chymotrypsin was only 3.3%. IVF with ICSI remains the only highly effective treatment of this disorder.

Chymotrypsin↗

Renin-angiotensin-aldosterone system, electrolyte homeostasis and blood pressure in alloxan diabetes.

The effect of a chronic glucose osmotic diuresis on electrolyte homeostasis was evaluated in alloxan diabetic rats with urine volumes greater than 150 ml/day and glycosuria of 4 to 10 gm/day. Results were compared with control rats for periods up to 84 days. Sodium and potassium intake and urinary losses were significantly higher in diabetic animals throughout the study periods. Negative Na balance, however, persisted for only four days, and negative K balance for only 18 days. Blood volumes were elevated probably secondary to the osmotic effect of hyperglycemia (serum glucose greater than 600 mg %). Plasma renin activity decreased progressively, in part because of an early decrease in renin substrate at a time when renin concentration was normal. Despite hyperkalemia, mean plasma aldosterone was not increased compared with that in control rats, suggesting diabetic rats had relative hypoaldosteronism. Although three diabetic rats became hypertensive, no significant difference in mean blood pressure was observed between the groups. The results suggest that diabetic rats have losses of Na and K early in their diabetes, following which mechanisms to conserve Na and K are activated preventing further electrolyte depletion despite continuation of the osmotic diuresis. Decreased renin activity with inadequate stimulation of aldosterone would contribute to K conservation. Maintenance of Na balance must be explained by increased Na intake and other renal Na conserving mechanisms.

Aldosterone↗

Multidrug-resistant tuberculosis in Alberta and British Columbia, 1989 to 1998.

OBJECTIVE: To describe the extent of the problem of multidrug-resistant tuberculosis (MDR-TB) in Alberta and British Columbia from 1989 to 1998. DESIGN: A retrospective, population-based descriptive study of all notified MDR-TB cases in the context of all notified TB cases, all notified culture-positive TB cases and all notified drug-resistant TB cases. SETTING: Provinces of Alberta and British Columbia, and their TB registries. PATIENTS: All people with TB reported to the TB registries of Alberta and British Columbia between January 1, 1989 and June 30, 1998. MAIN OUTCOME MEASURES: Drug susceptibility testing was performed in all cases of culture-positive TB. Demographic, clinical and laboratory data on all cases of MDR-TB were recorded. RESULTS: Of 4606 notified cases of TB, 3553 (77.1%) were culture positive. Of these, 365 (10.3%) were drug resistant; of the drug-resistant cases, 24 (6.6%) were MDR. Most MDR-TB patients were foreign-born; of the four Canadian-born patients, two were infected while travelling abroad. Although foreign-born patients were significantly more likely to harbour drug-resistant strains, 14.3% versus 4.8%, respectively (P<0.001), among those who were harbouring a drug-resistant strain, the proportion of Canadian-born versus foreign-born patients with an MDR strain was the same (6.7% versus 6. 6%, respectively). From 1994 to 1998 versus 1989 to 1993, the proportion of all drug-resistant strains that were MDR was greater (9.0% versus 4.3%, respectively), but the difference was not statistically significant. Isolates from 16 of the 24 MDR-TB cases had been archived. Each of these was fingerprinted and found to be unique. Most MDR-TB cases (88%) were respiratory. Of those tested for human immunodeficiency virus (n=17), only one was seropositive. MDR-TB was 'acquired' in 67% and 'primary' in 33% of cases. Eight (33%) of the MDR-TB cases received curative courses of treatment, six (25%) are still being treated, and the remainder have either died (five, 21%), transferred out (four, 17%) or become 'chronic' (one, 4%). No secondary case of MDR-TB has been identified in Alberta and British Columbia. CONCLUSIONS: Most MDR-TB in Alberta and British Columbia is imported. The proportion of all drug-resistant cases that are MDR appears to be increasing, but not because of disease acquired from recent contact with MDR-TB in Canada.

Adult↗

'Pseudo' treatment failure of pulmonary tuberculosis in association with a tuberculoma.

Failure of tuberculosis patients to respond to treatment is usually explained by one or more of five mechanisms: improper drug prescription; patient nonadherence to prescribed therapy; primary or acquired drug resistance; drug malabsorption; and rarely, exogenous reinfection with a drug-resistant isolate. Response to treatment is best measured bacteriologically; two different smear and one culture criteria for failure are widely used. Patients meeting either smear, but not culture, criteria for treatment failure may be said to have 'pseudo' treatment failure. Whether a patient can meet both smear criteria for failure, and not have a mechanism for treatment failure nor meet culture criteria, is unknown. A case of 'pseudo' treatment failure is reported in which both smear criteria for failure were met, but no mechanism for failure was proven to be operative.

Antitubercular Agents↗