Biomedical subjects

M A Castillo

Publications and source records attributed to M A Castillo.

8 recordsLinked to original sources

PubMed1992

Methimazole treatment reduces cardiac hypertrophy and mortality without a concomitant reduction in blood pressure in established Goldblatt two-kidney one clip hypertension.

The effects of methimazole, an antithyroid drug, on blood pressure and other parameters were evaluated in the established phase of Goldblatt two-kidney one clip (G2K-1C) hypertension. Methimazole was administered via drinking water for five weeks, starting five weeks after hypertension had been induced. After this period of treatment, similarly high blood pressures were observed in methimazole-treated and non-treated G2K-1 C rats, despite the fact that a hypothyroid state had been achieved in methimazole-treated rats. Methimazole-treated G2K-1 C rats showed reductions in heart rate, ventricular weight, ventricular/body weight ratio and mortality in comparison with rats not treated with methimazole. These results clearly demonstrate that hypothyroidism induced by methimazole: a) does not reverse G2K-1 C hypertension, but b) improves the rate of survival and c) reduces relative cardiac hypertrophy, possibly by the reduction in cardiac work observed in Goldblatt hypothyroid rats.

Animals↗

PubMed1992

Effects of methimazole on low-renal-mass hypertension: changes in blood pressure and pressor responsiveness to vasoconstrictors.

The administration of the antithyroid drug methimazole to rats via drinking water prevented the development of hypertension that usually accompanies subtotal nephrectomy and saline drinking (1% NaCl). In methimazole-treated rats, elevated blood pressure induced 5 weeks previously returned to normotensive levels. Pressor responsiveness to angiotensin, vasopressin and norepinephrine in unanesthetized rats was studied after prevention of hypertension in control, low-renal-mass hypertensive (LRM) and low-renal-mass methimazole-treated (LRM-M) rats, and in the reversion study in LRM and LRM-M rats. In LRM rats, responsiveness to vasoconstrictors was increased, whereas responsiveness to vasoconstriction was clearly reduced in LRM-M rats after prevention and reversion studies. These results suggest that (a) thyroid hormones are required in the early and established phases of LRM hypertension, and (b) the decreased pressor responsiveness to vasoconstrictors may play a role in the prevention and reversion of this type of hypertension following methimazole administration. However, the changes in pressor responsiveness may also be secondary to the reduction in blood pressure.

Administration, Oral↗

PubMed1991

Urinary excretion of digoxin-like immunoreactive factor and arginine-vasopressin in rats after several osmotic loads.

Urinary digoxin-like immunoreactive factor (DLIF), arginine-vasopressin (AVP) and other urinary parameters were investigated under normal conditions and after the i.p. injection of the following solutions: distilled water, isotonic and hypertonic NaCl, NaHCO3, KCl and urea, at a rate of 3 ml/100 g body weight. The measurement of digoxin-like immunoreactivity by two different radioimmunoassays showed that DLIF was stimulated by all volume loads regardless of the presence or absence of osmolar compounds. This dissociation between DLIF and urinary sodium excretion suggests that DLIF may not constitute the natriuretic hormone. Moreover, a dissociation between DLIF and AVP excretion also were found, which speaks against the hypothesis of a common mechanism of stimulation for both substances.

Animals↗

PubMed1990

[Developement and quality control of a radioimmunoassay for measurement of endogenous digoxin].

It has been suggested that sodium renal excretion is regulated, at least partially, by a factor with natriuretic properties called digoxin-like factor (DLF). As this substance crossreacts with digoxin antibodies, it was measured with a radioimmunoassay used to determine exogenous digoxin. Methodological conditions and quality control to determine DLF in plasma and urine have been established. Good correlation coefficients in specificity as well as dilution studies were obtained. Within--and between--assay coefficients of variations indicate good reproducibility. Moreover, changes in plasma DLF levels were detected in patients with cirrhosis or with renal failure, diseases which thrive on alterations in salt and water metabolism. In conclusion, this radioimmunoassay method for measuring DLF may be useful to investigate the role of this factor in several physiological and pathological conditions.

Adolescent↗

PubMed1989

Effects of selective and non-selective beta 1-blockade on renin secretion in the isolated rat kidney.

The participation of beta 1-adrenoceptor on renin secretion was studied in perfused rat kidney. Administration of propranolol, inhibited the renin release mediated by isoproterenol. Likewise, metoprolol and practolol, showed a similar potency to propranolol in inhibiting isoproterenol-induced renin secretion. These results suggest that the for isoproterenol-induced renin release in rats is a beta 1-type adrenoceptor.

Adrenergic beta-Antagonists↗

PubMed1988

Decrease in tumor-cell attachment and in a 140-kDa fibronectin receptor correlate with greater expression of multiple 34-kDa surface proteins and cytoplasmic 54-kDa components.

B16 melanoma cells attach to matrix-bound fibronectin but fail to adhere to albumin-coated surfaces supplemented with soluble fibronectin. Attachment to substratum is also decreased in the presence of an adhesion-disrupting antibody, or when cells are seeded on substrates poorly adhesive for these cells, such as collagen gels. We have now investigated some of the more general adhesion-related alterations that occur between flattened and poorly attached cells. Immune blots of octylglucoside extracts with the adhesion-disrupting IgG revealed a 140-kDa component in flattened cells, in contrast to the increased detection of a 54-kDa species in a comparable assay with rounded cells. Surface iodination also showed a decreased external exposure of a 140-kDa fibronectin binding species and an increased labelling in multiple 34-kDa protein species, in cells with decreased attachment to substratum. Analysis of 35S-methionine-labelled cell aggregates cultured on collagen gels also revealed a decrease in the 140-kDa region and a greater labelling of multiple 54-kDa components, compared to the same cells flattened on fibronectin. A change in 54- and 34-kDa species was also seen in matrix-associated components of rounded cells that failed to attach with soluble fibronectin. Since the 34-kDa species increase in poorly adherent cells is mainly detected by iodination, and the 54-kDa species increase in the same cells is partly associated with the corresponding detergent-insoluble matrices, we propose that these 2 novel proteins may relate to cell rounding, through a transmembrane modulation involving both surface membrane and cytoskeletal structures.

Animals↗

PubMed1988

[Teaching-inservice integration in primary care. Experience of the Facultad de Enfermería de la Universidad Autónoma de Nuevo León, Mexico].

This paper presents the reasons which justify the need to integrate teaching in-service and health care delivery in nursing, and the mechanisms to achieve efficiency in health programs. In 1976 the Autonomous University of Nuevo Leon (Universidad Autónoma de Nuevo León), as an educational and training center and as a means for scientific and humanistic endeavor to foster the development of the community it serves, began a joint experimental project with the health sector, by means of the Guadalupe Health Program and the Nursing Development Program, with the participation of the Schools of Medicine, Nursing and Dentistry. Special importance is attached to the objectives and organization of these nursing programs, the teaching in-service methodology, and the functions and responsibilities of teachers, students and support staff. The achievements of eleven years of work are reported.

Education, Nursing↗

PubMed1985

Serum mediated changes in cell attachment and cytoplasmic organization of B16 melanoma correlates with selective alterations in secreted proteins.

B16 melanoma cells exhibited decreased adhesion to substration and the presence of cytoplasmic granules, resembling lipid inclusions, when cultured in vitro in the presence of syngenic serum from C57/BL6 mice. This constrasted with the rapid cell attachment and absence of cytoplasmic granules in cultures seeded in medium supplemented with an identical concentration of fetal bovine serum. Electrophoretic comparison of intracellular proteins revealed similar patterns in detergent-soluble and matrix-associated proteins from cells grown with bovine or mouse serum. However, a similar analysis of the conditioned media showed clear differences in methionine-rich species which migrated in the 100 kd region in cells grown with bovine serum, and as 110 kd component in cells grown with mouse serum. Our data indicate that the poor attachment to substratum and changes in cytoplasmic organization of B16 melanoma cells, is primarily associated with specific changes in secreted proteins.

Animals↗