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Biomedical subjects

F Alba

Publications and source records attributed to F Alba.

71 records · Page 4Linked to original sources
PubMed1979

Effect of sodium and osmolarity on renin secretion.

The effect of changes in sodium and osmolarity on renin secretion has been studied in the isolated perfused rat kidney. Perfusion with low sodium buffer (110 mM/l) produced a significant increase in renin secretion compared with control experiments (Na+:135 mM/l). Since the presence of tubules seems necessary for such an effect to take place, it suggests that the high renin secretion stimulated by a low sodium buffer centers in the Macula densa. Perfusion with high sodium buffer (170 mM/l; osmolarity 350 mOs/l) induces a stimulation on renin release. However, a greater rise in renin is achieved in control experiments if choline chloride increases the osmolarity from 300 to 350 mOs/l. All this suggests that high sodium buffer, independently of its osmotic effect, has an inhibitory role on renin release.

Animals↗
PubMed1978

[Effects of postural changes and volume depletion on renin-angiotensin system (author's transl)].

The effects of orthostatism and furosemide tests on different parameters of renin-angiotensin system have been studied in 14 normal human subjects. Both tests produced a significant increase in plasma renin activity and plasma renin concentration. Plasma substrate concentration was slightly, but significantly, increased on the furosemide test. Plasma aldosterone rose in both tests, while aldosterone urinary excretion decreased after orthostatism and increased after furosemide.

Adult↗
PubMed1977

Stimulation of renin release by prostaglandin E2.

The effect of different doses of prostaglandin E2 on renin secretion in isolated perfused rat kidney has been studied. The infusion of 5 ng/ml of prostaglandin E2 produced a significant rise on renin secretion compared with control group. A dosage increase of prostaglandin E2 (10 and 50 ng/ml) produced an increase in the released renin. From this a correlation between doses and responses can be obtained. The perfusion pressure was slightly--but significantly--modified with the highest dose of prostaglandin (50 ng/ml). The possible pathways of action are dicussed.

Animals↗
PubMedDate not supplied

Differential effects produced by an anticholinergic on the neuroleptic inhibition of motor behaviour and self-stimulation of the prefrontal cortex in the rat.

A specific dopamine receptor blocker, spiroperidol (0.016, 0.032, 0.064 and 0.128 mg/kg) alone or in combined treatment with the centrally acting anticholinergic, dexetimide (0.5, 1.0 mg/kg) was given intraperitoneally to rats pressing a lever for brain self-stimulation through electrodes implanted in the medial prefrontal cortex. The same treatment was also given to rats in which the spontaneous motor behaviour was measured. Spiroperidol produced a dose-related inhibtion of both self-stimulation and spontaneous motor activity. Dexetimide, given to spiroperidol treated rats, was able to antagonize the motor impairment produced by spiroperidol, but prefrontal cortex self-stimulation remained decreased. These data support the suggested role for dopamine in self-stimulation of the prefrontal cortex in the rat.

Animals↗
PubMedDate not supplied

Effects of dietary supplementation with fish oil, lard, or coconut oil on oxytocinase activity in the testis of mice.

Oxytocin (OT), locally synthesized in the testis, is involved in androgen biosynthesis. The use of polyunsaturated fatty acids (e.g., fish oil) in the diet may improve the fertilizing ability in mammals. Cystinyl aminopeptidase (oxytocinase) activity plays a major role regulating the functional status of OT. Sex steroids and the type of the fatty acid used in the diet modify aminopeptidase activities in serum. In the present study, the authors compared the effect of a fish oil supplemented diet with two other diets supplemented with saturated oils (lard and coconut) on oxytocinase activity in the testis of mice. The enzymatic activity was determined fluorometrically using cystinyl-beta-naphthylamide as substrate. The results demonstrated higher levels of oxytocinase activity in mice fed the diet supplemented with fish oil than in those that were fed diets containing lard or coconut oils. The testicular functions in which OT is involved may be attenuated by the use of fish oil in the diet.

Animals↗
PubMedDate not supplied

[Population and development in Mexico: a synthesis of recent experience].

Changes in the relationship between population factors and the development process in Mexico from 1940 to the present are reviewed. The authors show how the development that occurred up to about 1970 both absorbed and encouraged rapid population growth. They then describe how the emergence of problems concerning this relationship led to the development of a population policy during the 1970s. "The paper then takes up the implementation of that policy and the determinants of the fertility decline that took place afterwards, and closes with a brief review of the implications that demographic considerations have for Mexico's future." (SUMMARY IN ENG)

Americas↗
PubMedDate not supplied

[Urban aspects of labor migration: the situation in the countries of origin].

"A bibliographical review serves to analyze the role of urban growth in patterns of international labor-force migration, as well as the effect of this migration on the development of the countries of origin, especially on their cities. While the review confirms the general idea that international migrants are either peasants or highly qualified personnel, it also shows that qualified workers are increasingly involved in international labor movements and that a great part of them come from large cities. It is to be expected that in these circumstances large cities of the countries of origin will become more integrated to international migratory systems." (SUMMARY IN ENG)

Demography↗
PubMedDate not supplied

[Interhemispherical study of the activities of aminopeptidases, lactate dehydrogenase and glutamate-oxaloacetate transaminase in the rat brain].

Aminopeptidase activity has been assayed from both soluble and membrane bound fractions in eleven regions of the left and right hemispheres of the rat brain, using L-leucine-2-naphthylamide as substrate. Two other metabolic enzymes, lactate dehydrogenase and glutamate-oxalacetate aminotransferase activities were simultaneously determined in the same areas. When individual zones of the left hemisphere were compared with its corresponding right zones, soluble aminopeptidase activities were significantly higher in left frontal cortex and left hypothalamus than in right frontal cortex and right hypothalamus, respectively. No other significant differences were found neither in the remaining areas nor for the other enzymatic activities between both brain hemispheres.

Aminopeptidases↗
PubMedDate not supplied

[Demographic and economic development in contemporary Mexico].

This paper briefly reviews the main features of the recent Mexican experience in demographic and economic development matters. It assesses the development pattern that prevailed between 1940 and 1970 and the ways and policies that were instrumental in accommodating the rapid population growth of the period. The author considers that by 1970 the relatively acceptable demo-economic system in place since 1940 entered a period of emerging tensions, and examines the responses to those difficulties, among them the change in population policy. It closes with a brief review of the tasks ahead considering future demographic and economic tendencies in Mexico.

Demography↗
PubMedDate not supplied

[A fluorimetric method for the determination of brain aminopeptidases].

A fluorometric method adapted to the determination of brain aminopeptidase activities has been developed in our laboratory. This method is based in the fluorescence produced by 2-naphthylamine when it is released from aminoacyl-2-naphthylamides under the hydrolytic action of these enzymes. Values of enzymatic activities and kinetic constants are similar to those previously described in the literature.

Aminopeptidases↗