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Biomedical subjects

A Escalante

Publications and source records attributed to A Escalante.

64 records · Page 4Linked to original sources
PubMed1990

The effect of testosterone on the immune response. 1. Mechanism of action on antibody-forming cells.

Sex hormones are known to be implicated in humoral and cellular immune responses. In this study we report the effects of orchidectomy and testosterone replacement on the immune response using T-dependent and T-independent antigens. It was found that the response was dependent on the nature of the antigen employed and on the presence of testosterone. The absence of testosterone receptors in spleen lymphocytes was also found. An hypothesis that testosterone regulates the immune system through the enhancement of suppressive activity is advanced.

Animals↗
PubMed1989

Inhibitory action of various 5-HT1B receptor agonists on rat masculine sexual behaviour.

The systemic administration of the 5-HT1B receptor agonists, RU 24969 (0.25 and 0.5 mg/kg), TFMPP (0.25 and 0.5 mg/kg) and mCPP (0.75 and 1.0 mg/kg) resulted in an inhibition of rat masculine sexual behaviour reflected as a reduction in the proportion of copulating animals. Additionally, the analysis of the sexual behaviour of the animals obtaining ejaculation revealed that RU 24969 and TFMPP administration resulted in an increase in the number of mounts and in a prolongation of the intromission and ejaculation latencies and of the postejaculatory interval. Administration of mCPP increased the number of mounts preceding ejaculation. None of these changes could be attributed to a motor coordination impairment since none of these drugs, at the doses tested, produced changes in a treadmill test. The administration of the 5-HT1A agonist, ipsapirone (2.5, 5 and 10 mg/kg) resulted in a facilitation of the sexual behaviour expressed as a reduction in the number of intromissions preceding ejaculation accompanied by a shortening of the ejaculation latency. Present data show a differential action of 5-HT1A and 5-HT1B receptor subtypes in the control of rat masculine sexual behaviour. The hypothesis that the endogenous serotonin inhibitory action on copulation is mediated via the 5-HT1B receptor subtype is proposed.

Animals↗
PubMed1989

Effect of albendazole in experimental toxocariasis of mice.

Fifty-five mice were each infected with 800 embryonated eggs of Toxocara canis. Beginning on the second day of the infection, one group received a single 9 mg dose of albendazole every 24 hours for an eight-day period while a second group received 3 mg of albendazole every eight hours for the same period. On the tenth day of infection, mice in each treatment group and their corresponding controls were sacrificed, and the presence and motility of T. canis larvae in the brain were determined. With both therapeutical procedures the administration of albendazole reduced the number of larvae which reach the brain. However, for the same total dose, the administration of the drug every eight hours yielded results which were significantly superior to those produced by administering a single dose every 24 hours, reducing both the number of larvae in the brain and their motility.

Albendazole↗
PubMed1989

Acute myelocytic leukemia after the use of cyclophosphamide in the treatment of polyarteritis nodosa.

The use of cyclophosphamide has been associated with the delayed appearance of neoplasms. We report a woman who developed myelodysplastic syndrome leading to acute myelocytic leukemia, 4 years after receiving 13 g of cyclophosphamide over 6 months for severe polyarteritis nodosa. Cytogenetic abnormalities typical of damage induced by alkylating agents, including partial deletions of chromosomes 5 and 7, were present. This case represents the first reported occurrence of cyclophosphamide associated malignancy in polyarteritis nodosa.

Adult↗
PubMed1988

Morphological differences between Venezuelan and African microfilariae of Onchocerca volvulus.

Comparative morphological and biometric characteristics of microfilariae of Onchocerca gutturosa and O. volvulus from different geographical areas (Upper Orinoco, Venezuela; Togo; Liberia) were assessed. "Stepwise" discriminant analysis and Mahalanobis estimators were applied to measure distance between populations. The results indicate a strong similarity between the two strains from the Upper Orinoco (Venezuela) and the Togo strain, as well as a clear separation between these strains and that of O. gutturosa. The Liberian strain was easily distinguishable from microfilariae from Togo and Venezuela. Discriminant analysis showed the Liberian deme to be as different from the Venezuelan and Togo demes as these demes were from microfilariae of the reference species, O. gutturosa. Although it is necessary to confirm these data using formalin-fixed specimens obtained from the skin, the present findings suggest the existence of geographically-different strains of O. volvulus in America and Africa.

Animals↗
PubMedDate not supplied

[Usefulness of laryngeal stroboscopy].

The extended use of optic fibers and TV cameras and videos make easier the stroboscopic exploration of the vocal folds. The ENT surgeons must stress the use of this unique method which allows us the study of the laryngeal voice function. This exploration is based on a fictional slow motion movement of the vocal fold that lets us see the mucosal wave. The most useful clinical implications of the laryngeal stroboscopic study are: phonatory function, differential diagnosis between benign and malignant lesions and laryngeal paresis.

Biophysical Phenomena↗