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M Ruiz

Publications and source records attributed to M Ruiz.

At least 217 records · Page 12Linked to original sources
PubMed1988

Postnatal development of the renin-angiotensin system in thyroidectomized rats.

Postnatal changes in plasma renin activity (PRA), plasma renin concentration (PRC), plasma renin substrate (PRS) and plasma angiotensin II concentration (AII) were studied in young thyroidectomized rats from the 4th to the 10th week of life. Although there were no differences in the PRA pattern between thyroidectomized and euthyroid animals, an increase in PRC from the 6th week of life, together with a reduction of the glomerular filtration rate (GFR) and an increase in the fractional excretion of sodium (FENa) from the 8th week of life, was observed in young hypothyroid animals. Moreover, in thyroidectomized animals, PRS and AII declined until the 10th week of age, while in euthyroid animals an increase of PRS and AII was observed between the 8th and 10th weeks of life. These results show that the changes in sodium renal handling following thyroidectomy could have an influence on the RAS components.

Aging↗
PubMed1988

Evaluation of patients and partners 1 to 4 years after penile prosthesis surgery.

One to 4 years after penile prosthesis implantation 52 men and 22 partners were interviewed personally. All except 4 patients were having intercourse on a regular basis. A quarter of the patients reported restriction in intercourse positions, possibly because of a smaller penis postoperatively, and 15 per cent reported decreased orgasm intensity. Six men had an undiagnosed prosthesis malfunction or they used an inadequate pumping technique, suggesting that prosthesis patients should be followed on a continuing basis. The 52 men had experienced 10 malfunctions with the prosthesis. Partial erections were reported by 69 per cent of the patients but this could be confirmed in only 1 of 10 with visual sexual stimulation testing. It is suggested that differences between prosthesis models are more a result of psychological, relationship and health factors than mechanical factors. Of the patients 79 per cent would undergo the operation again but only 59 per cent of the partners had no hesitations. The longer the postoperative period the more hesitations. A satisfaction score was used to measure patient satisfaction.

Coitus↗
PubMed1987

Effect of various components of the renin-angiotensin-aldosterone system on angiotensinogen production in a monolayer culture of adult rat hepatocytes.

A monolayer culture of adult rat hepatocytes was used to study the effect of various components of the renin-angiotensin-aldosterone system (angiotensin II, aldosterone and angiotensinogen), and intracellular sodium depletion (by ouabaine addition) on the angiotensinogen production rate. Normal hepatocytes synthesized linearly angiotensinogen for 6 h at a mean rate of 110 pg angiotensin I generated/mg intracellular protein each h. The addition of hydrocortisone (0.1 microM) to the culture medium significantly enhanced the angiotensinogen production after 2 h of incubation (P less than 0.05), being about 2-fold higher than normal control values at the 6th h of incubation. In contrast to this increase, the addition of angiotensin II (70 nM) to the medium produced a higher stimulatory effect on angiotensinogen synthesis, being the differences with the control significants after 1 h of incubation (P less than 0.01). At the 6th h of incubation, angiotensin II enhanced the angiotensinogen production over 2 fold in relation to the control group. No change in the angiotensinogen production rate was observed in monolayer culture of hepatocytes in the presence of aldosterone (1 microM), angiotensinogen (0.1 microM) or ouabaine (10 microM). These results provide further evidence that angiotensinogen synthesis is subject to a positive feed-back mechanism by angiotensin II, indicating that this mechanism takes place at physiological levels of plasma AII.

Aldosterone↗
PubMed1987

Effect of thyroid hormones on angiotensinogen production in the rat in vivo and in vitro.

The influence of thyroid hormones on angiotensinogen production was studied in vitro and in vivo. In the in-vitro system, angiotensinogen production rate (APR) of monolayer cultures of rat hepatocytes in response to tri-iodothyronine (T3) and thyroxine (T4) was assayed. In the in-vivo system, plasma angiotensinogen concentration (PAC) and liver angiotensinogen content (LAC) were measured in hyper- and hypothyroid rats. In both thyroid dysfunctions, a significant decrease of PAC was found compared with that in control animals; however, LAC showed a significant increase in hyperthyroidism and a marked decrease in hypothyroidism. As PAC is dependent upon both angiotensinogen production by the liver and angiotensinogen degradation by renin, the decrease in PAC observed in hyperthyroidism could be due to an increase in plasma renin concentration, which would overcome the increased synthesis of liver angiotensinogen observed in these animals. In fact, addition of various concentrations of T4 or T3 to monolayer cultures of adult rat hepatocytes significantly enhanced APR. This increase was greater and started earlier with T3 (1196.1 +/- 143.7 (S.D.) pg/mg protein per 6-h incubation; significant differences at the third hour of incubation) than with T4 (858.3 +/- 88.2 pg/mg protein per 6-h incubation; significant differences at the sixth hour of incubation). In addition, a close dose-response relationship was found in the cultures supplemented with T3. The different time-course in the response elicited by T3 and T4 on APR could be a consequence of the necessary transformation of T4 into T3 to acquire biological activity.

Angiotensinogen↗
PubMed1987

[Gynecomastia].

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Adolescent↗
PubMed1986

Postnatal development of renin-angiotensin system in rats.

The changes occurring in several components of the rat renin-angiotensin system (RAS) were studied for the brief postnatal period, between the fourth and tenth week of life. The parameters were: plasma renin activity (PRA), plasma renin concentration (PRC), plasma renin substrate (PRS) and the plasma angiotensin II concentration (AII). A gradual decrease in PRA with age was noticed. Between the fourth and the eighth weeks of life, this was attributed to a corresponding decline in both PRC and PRS. However, between the eighth and tenth weeks, no changes in PRA could be detected, but PRC and PRS increased, perhaps as a consequence of the changes in renal function and the AII increase observed. In this second period, simultaneously with the RAS changes described, there was reduced sodium chloride excretion as the glomerular filtration rate (GFR) stabilized. The data presented suggest that this postnatal period is critical, in rats, for the maturation of the RAS component control mechanisms; they appear to be closely related to the development of the renal function.

Angiotensin II↗