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A Aranda

Publications and source records attributed to A Aranda.

7 recordsLinked to original sources
PubMed1992

The thyroid hormone response element is required for activation of the growth hormone gene promoter by nicotinamide analogs.

N'-Methylnicotinamide and nicotinamide, which decreased in vitro ADP-ribosylation of nuclear proteins and/or cellular NAD+ content, selectively increased the basal expression of the rat growth hormone (GH) gene promoter and its response to triiodothyronine (T3). This increase was not found when the thyroid hormone response element (TRE) was deleted from the promoter. Transfection with an expression vector for the T3 receptor inhibited basal activity of the TRE-containing promoter and repressed the stimulatory effect of N'-methylnicotinamide. The addition of hormone relieved this inhibition and enhanced transcription above levels found in the absence of the transfected receptors. These results suggest a modulatory role of ADP-ribosylation in hormonal regulation of gene expression.

Adenosine Diphosphate Ribose↗
PubMed1992

Impairment by cyclosporin A of reperfusion-induced arrhythmias.

This study introduces the immunosuppressor, cyclosporin A, as a cardioprotective drug. This effect was analyzed during development of reperfusion/induced arrhythmias after 5-min period of coronary ligation in hearts of rats under anesthesia. The results indicate that cyclosporin, when given before coronary occlusion, at a dose of 20 mg/kg, effectively protects against the high incidence of arrhythmias and the fall in blood pressure induced by reperfusion. In addition, in inhibits the delivery of lactic dehydrogenase and creatine kinase enzymes to the plasma. We propose that the protective effect could be related with its well documented action to restrain Ca(2+)-induced damage of mitochondrial functions.

Animals↗
PubMed1979

Attempts to induce ovulation in amenorrheic patients using D-Ala-6-LH-RH propylamide.

Thirteen amenorrheic patients, two with primary amenorrhea, and eleven with secondary amenorrhea, including five with anorexia nervosa, were treated with an analog of LH-RH, D-Ala-6-desGly-10-LH-RH propylamide (D-Ala-6-LH-RH PA). The patients were follwed with checks of daily basal body temperature, cervical mucus characteristics, urinary total estrogens and pregnanediol, plasma LH and FSH, and twice-weekly clinical checkups. D-Ala-6-LH-RH PA was given continuously for 11 days at a dose of 50 microgram im from the 4th day of a steroid-induced cycle. Ethynyl estradiol (50 microgram orally) was given twice on day 14 followed by 250 microgram of D-Ala-6-LH-RH PA for the following 3 days. All the treated cycles were monophasic. Withdrawal bleeding occured in nine patients from the 4th to 6th days posttreatment. A significant total maximal increment in estrogens was found in seven patients, which was higher than the values obtained previously in the same patients with human menopausal gonadotropin. One patient conceived in the cycle immediately following discontinuation of treatment, indicating a possible effect of analog on the follicular development during the treatment; a normal baby was delivered. A second patient conceived three cycles afterwards, and two other patients began normal menstrual cycles.

Adult↗
PubMed1976

Effects of small doses of L-thyroxine and triiodo-L-thyronine on pituitary LH content of thyroidectomized rats.

Pituitary LH was studied by means of a specific radioimmunoassay (RIA) in male rats at different time intervals after thyroidectomy (T), and in rats which were T at least 30 days before and were then treated with different doses of L-thyroxine or triiodo-L-thyronine. A decrease in the pituitary LH of the T animals, with respect to the intact age-paired controls, was demonstrable from 13 days after the operation, when total pituitary LH content was taken into consideration, or from 5 days after T, when the LH concentration (mug/mg pituitary) was considered. Doses of thyroid hormones lower than the daily maintenance dose for the rat produced very little effect on the pituitary LH levels of T animals. However, a single dose of 1.75 mug of T4 or 0.2 mug of T3 (doses approximately equivalent to the T4 and T3 maintenance dose for T rats) induced such a rapid and intense increase in the pituitary LH content that it no longer differed from that of the intact age-paired controls by 12 hours. Surprisingly, 5.0 mug of T4 and 1.0 mug of T3 did not produce any increase in the pituitary LH content of T rats.

Animals↗
PubMedDate not supplied

[Interaction of a mixture of epimastigotes and tripomastigotes from a culture of a Mexican isolate of Trypanosoma cruzi with mouse macrophages].

Chagas disease, a cause of important morbo-lethality in Latinamerica, is produced by a protozoan which has a circulating and tissular phase the Trypanosoma cruzi. Adhesion between T. cruzi and phagocytes is the first step in cellular parasitism, which has a central role in pathogenesis. Although there are studies on parasite phagocyte interaction with some strains of T. cruzi, and it is known that biological variation does exist. We now report the first studies with a mexican isolate using a mix of different phases of T. cruzi obtained from acellular culture resembling the natural conditions. Murine macrophages adheres to epimastigotes, transitional trypomastigotes and metacyclic trypomastigotes since the first minutes of observation, progression on cell-cell interaction was demonstrated, there were no differences among parasite faces however, in some cases there was a failed adhesion, this suggest a possible parasite evasion mechanism. These studies limited only to morphologic aspects the adhesion phenomena, should be pursued.

Animals↗
PubMedDate not supplied

[Analysis of rheumatic valvulopathy with scanning electron microscopy].

There is a high incidence of rheumatic endocarditis in our environment. Therefore it is important to know the structural characteristics of the valvular lesions in order to better understand the physiopathologic pathways of tissue injury. We have chosen a non-conventional method, the scanning electron microscopy. There were very few such reports in the current literature. We analyzed ten mitral valve with rheumatic scarring lesion and five normal, as a control group. We were able to establish three structural patterns. 1) Stone pavement like (endocardium with nuclear bulge cells and marginal folds at the cell boundaries, abundant number of microvillous projections and few areas of endothelial loosening). 2) Cerebroid (subendothelium with wrinkles caused by deformity of the valve with or without endothelial loosening) and 3) Smooth pattern (flattened endothelium with scanty microvillous projections and abundant areas of endothelial denundation and exposition of subendothelium). More damage was noted in the auricular surface of the rheumatic group, characterized by a predominance of the smooth pattern. We found Lambl's excrecences in two mitral leaflets, they were formed by collagen break fascicles of the subendothelium. This technique allowed us to analyze integrity of the endocardial selective barrier and the interactions between the damaged surface of the valve and elements of the peripheral blood and showed more endocardial injury in the rheumatic group. These alterations could play an important role in the pathogenesis of this disease.

Adult↗