Induction of intrauterine growth restriction with a low-sodium diet fed to pregnant rats.

OBJECTIVE: A low-sodium diet fed to female rats before mating through parturition leads to pups of lower weight. We characterized the effect of low dietary sodium during the last week of gestation (after fetal organogenesis) on fetal and maternal homeostasis. STUDY DESIGN: Pregnant Sprague-Dawley rats were randomly assigned to a control group or to a group fed a low-sodium diet from gestational days 15 through 22. Systolic blood pressures were measured throughout pregnancy. On day 22 plasma volume was measured and blood samples were taken for electrolyte and hormonal measurements. Fetal and placental weights were also determined. RESULTS: Plasma renin activity and aldosterone level were significantly higher in the experimental group than in the control group. Plasma volume was significantly lower in pregnant rats receiving a low-sodium than in those receiving a control diet. Rats receiving a low-sodium diet had pups of lower weight and length (4.45 +/- 0.22 g, 3.90 +/- 0.06 cm) than pups of the control group (5.21 +/- 0.12 g, 4.10 +/- 0.02 cm). Pups born to mothers with low-sodium diets recuperated from intrauterine growth restriction by 14 days after birth. CONCLUSION: These data indicate that a low-sodium diet given to pregnant rats for the last 7 days of gestation leads to reduced plasma volume expansion and fetal growth restriction. This could prove to be a simple animal model for studying the relationship between maternal plasma volume and fetal growth.

In vivo regulation of enzymes controlling aldosterone synthesis in pregnant rats.

There are two main regulatory sites of aldosterone biosynthesis, the early rate-limiting step by the P450scc and the final steps by the P450aldo. We have already demonstrated that, during gestation, activity and mRNA levels of P450aldo are increased. It has been shown that changes in sodium and potassium in the diet modulate the expression of P450aldo in adrenal zona glomerulosa (ZG). In the present study, we compared the effects of low-sodium (Na+) and high-potassium (K+) diet on the expression of enzymes controlling aldosterone synthesis during gestation. Pregnant and nonpregnant rats were randomly assigned to control group or to group receiving low Na+ or high K+ diet during the last week of pregnancy. By the end of the treatment, the two diets induced increases of plasma aldosterone and P450aldo mRNA levels in nonpregnant and pregnant rats. However, plasma renin activity and P450scc mRNA levels were only in the pregnant group fed the low Na+ diet. High K+ diet had no effect on these parameters. We, thus, suggest that the renin-angiotensin system and the enzymes implicated in aldosterone synthesis are differently regulated during gestation.

[Medical research in Chile: quantitative indicators]. / La investigacion medica en Chile. Indicadores epistemometricos.

Diverse indicators were used to examine medical research in Chile. According to participation in Fondecyt projects, it was concluded that 420 persons were involved in medical sciences research and that 41.9% of them had no postgraduate title. During the eighties, there was a clear aging of the community dedicated to medical research. The scientific productivity was assessed through the inventory of publications in indexed journals. During the eighties, the number of articles in Clinical Medicine and Biomedical Sciences increased two-fold. The University of Chile published the greatest number of articles, followed by the Catholic University and, with a remarkable lower amount, other Universities. The impact of the published articles in Clinical Medicine and Biomedical Sciences was calculated from the citations that they generated from 1986 to 1988. Likewise, the articles registered in 1985 with the higher citation indexes were identified.

[Cytological diagnosis of prostatic cancer by transrectal aspiration biopsy (author's transl)]. / Le cytodiagnostic des cancers prostatiques.

From the cytologic study of fifty transrectal needle aspirations of the prostate the authors try to establish the principles leading to the diagnosis of prostatic carcinoma. Correlation with clinical diagnosis shows that in positive cases, cytologic diagnosis is accurate. In the case of negative cytologic responses this negative response may be imputable: to the paucicellularity of the sample, unavoidable blind needle aspiration, an early necrosis of the cellular material, a false interpretation of minimal cellular and nuclear abnormalities. This method proves valuable for the clinician. In two cases out of three the cytological diagnosis confirms the clinical diagnosis.