Biomedical subjects
Publications and source records attributed to G Mendoza.
Myelopathy is a rare complication of chronic liver disease associated with extensive portal-systemic shunt of blood. Its main clinical feature is a spastic paraparesis without sensory or sphincteric impairment. We describe 3 patients who presented hepatic myelopathy following the performance of a portacaval shunt.
Semen was collected from six mature and sexually rested Angora bucks at one-hour intervals five times a day on each of 5 consecutive days in the breeding season. There was a marked decline in semen volume (P less than 0.001), sperm concentration (P less than 0.05) and number of spermatozoa (P less than 0.001) on consecutive days. Successive ejaculates within days differed only in number of spermatozoa (P less than 0.001). The following year at the beginning of the breeding season, the weights of testes and epididymides and the reserves of spermatozoa in these parts were examined after slaughter of the six bucks. The mean number of spermatozoa in the paired testes, capita, corpora and caudae of the epididymides were (22.8 +/- 1.24) x 10(9), (9.4 +/- 1.19) x 10(9), (3.4 +/- 0.22) x 10(9) and (35.0 +/- 2.21) x 10(9), respectively. Epididymal reserves of spermatozoa were correlated with testicular weight (r = 0.50, P = 0.01) and number of spermatozoa in the testes (r = 0.42, P = 0.07), but not with epididymal weight. The daily production of spermatozoa per animal in the breeding season was estimated to be 4.0-6.4 x 10(9).
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A candidate rabies reference vaccine of suckling mouse brain (SMB) origin was prepared and standardized at the Pan American Zoonoses Center (PAHO/WHO) and evaluated in a collaborative study involving seven laboratories. On the basis of three different tests, its potency, immunogenicity, and stability were demonstrated to be satisfactory. The vaccine was proposed for consideration of the Latin American and Caribbean countries as a regional standard to determine the potency of SMB vaccines, the most widely used in the Region.
Ejaculates were collected by artificial vagina from 11 Angora goats, once or twice weekly, between April and July in two successive years. The mean +/- SEM ejaculate volumes each year were 0.8 +/- 0.30 and 0.98 +/- 0.52 ml; the sperm concentrations were 3.33 +/- 0.49 and 2.94 +/- 0.45 x 10(9)/ml, and the pH values were 7.01 +/- 0.34 and 7.20 +/- 0.17. The concentrations (mg/100ml) of fructose (875 +/- 97) and lactic acid (73 +/- 17) in goat seminal plasma were sufficiently high to be important substrates for maintenance of sperm motility. Only trace amounts of glucose were present in seminal plasma. The glycerylphosphorylcholine (GPC) concentration of seminal plasma (809 +/- 154 mg 100 ml ) was correlated with whole semen sperm concentration (P < 0.001), indicating that GPC is of epididymal origin. Goat sperm are not likely to utilize GPC as a substrate and its metabolizable derivatives, glycerophosphate (3.3 +/- 1.1 mg 100 ml ) and glycerol (1.8 +/- 1.0 mg 100 ml ), were not present in sufficiently high concentrations to be significant as energy sources for the sperm. The mean concentration of citric acid was 331 mg 100 ml seminal plasma. Colored semen was consistently produced by eight bucks, and in yellow, light yellow and white ejaculates, the seminal plasma riboflavin (mug/ml) concentrations were 5.38 +/- 2.89, 3.09 +/- 0.85 and 1.73 +/- 0.88, respectively. This suggests that the color is due to riboflavin, which is probably produced by the vesicular glands since the concentration of riboflavin in the seminal plasma was correlated with fructose and citric acid levels.
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Post-thawing survival of ram sperm was examined after semen which had been layered on top of isolation columns containing solutions of bovine serum albumin (BSA) in Tris diluent was processed for freezing by the pellet method. Sperm isolated from the bottom of the BSA column had better post-thawing survival than sperm from the top of the column. The efficiency of sperm isolation was affected by the concentration of BSA in the column, the holding time of semen on the column and the concentration of sperm in the layered semen. The best post-thawing survival of sperm occurred when semen diluted to a concentration of 200 x 10(6) sperm/ml was layered on a column of 6% BSA in Tris diluent and the bottom layer of the column was isolated for freezing after two hours' holding time.
Two fertile women, mother and daughter, both presenting sex chromosomal mosaicism (45,X/46,XX/47,XXX and 45,X/46,Xr(X] are reported. The mechanisms through which a Turner women can eventually be fertile are discussed.
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Previous studies concerning the effect of cimetidine, a histamine H2 receptor antagonist, on histamine- or antigen-induced bronchoconstriction have yielded conflicting results. Therefore, we examined the effects of cimetidine on sensitivity to both histamine- and antigen-induced bronchospasm in 12 subjects with mild asthma (baseline FEV1 greater than 70% predicted). Bronchial challenges with inhaled histamine or antigen were performed 2 h after a single dose of 300 mg cimetidine or placebo orally administered in a random, double-blind manner on separate days. The provocative concentration of antigen or histamine that produced a 20% decline in FEV1 from the postdiluent control value (PC20) was determined and log transformed. Plasma cimetidine concentrations 2 h after oral administration (mean, 1.5 microgram/ml; range, 0.9 to 2.4 mirograms/ml) were above the minimal concentration required for suppression of gastric acid secretion. No difference was noted in FEV1, specific airway conductance, or partial expiratory flow rates after cimetidine compared with that after placebo, indicating the lack of any bronchospastic effect of cimetidine in the absence of histamine or antigen challenge. However, mean log PC20 of histamine (but not of antigen) was significantly less after cimetidine than after placebo (p less than 0.05), indicating that cimetidine augmented histamine-(but not antigen-) induced bronchospasm. Four of 12 subjects exhibited a significant (greater than or equal to fourfold) decline in PC20 for histamine after cimetidine compared with that after placebo but no subject demonstrated a significant (greater than or equal to tenfold) decline in PC20 of antigen. No relationship was apparent between baseline sensitivity to histamine and cimetidine effect on histamine sensitivity in individual subjects. We conclude that in subjects with mild asthma, cimetidine in the usual recommended orally administered dose can increase sensitivity to bronchospasm induced by histamine but not by antigen. These findings suggest that cimetidine in this dose has a blocking effect on H2 receptors in airway smooth muscle but that this effect is not sufficient to alter the net impact of immunologic release of mediators on the airways.
Two patients seen in a six-month period had a diffuse, multisystem disorder characterized by edema of the extremities and face, rash, bone pain and tenderness, symptoms of increased intracranial pressure, and hypercalcemia. Both had been receiving extraordinarily high doses of vitamin A for some time. Serum vitamin A concentrations were markedly elevated, and serum vitamin D concentrations were normal. The history of excessive vitamin administration was only elicited following the detection of hypercalcemia. This is a potential complication of the administration of unregulated food supplements, stressing the need for complete dietary histories in the evaluation of multisystem disorders, with or without hypercalcemia.
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