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Biomedical subjects

R Pastor

Publications and source records attributed to R Pastor.

28 records · Page 2Linked to original sources
PubMed1986

Effects of maternal iodine deficiency on the L-thyroxine and 3,5,3'-triiodo-L-thyronine contents of rat embryonic tissues before and after onset of fetal thyroid function.

Female rats were placed on a low iodine diet (LID) or LID supplemented with KI. They were mated 3-6 months later. Maternal and embryonic tissues were obtained both before the onset of fetal thyroid function, at 11 and 17 days of pregnancy, and at 21 days of gestation. T4 and T3 concentrations were measured by RIA. T4 concentrations were very low in the plasma, liver, and lung of LID dams and in all embryonic samples obtained from such mothers, namely 11-day-old embryotrophoblasts, 17-day-old placentas and embryos, 21-day-old placentas, embryos, plasma, liver, lung, and carcass (whole embryos minus the trachea, thyroid, blood, liver, and brain). T3 was low in 17-day-old placentas and embryos and in all fetal tissues obtained at 21 days of gestation from LID dams. These results show that when iodine deficiency is severe enough to result in very low maternal plasma T4 levels, embryonic tissues are deficient in T4 and T3 both before and after the onset of fetal thyroid function. This finding might be relevant to the etiopathology of human iodine deficiency disorders.

Animals↗
PubMed1985

Effects of maternal hypothyroidism on the weight and thyroid hormone content of rat embryonic tissues, before and after onset of fetal thyroid function.

Embryonic tissues were obtained from normal (C) and thyroidectomized (T) rats between 9 and 21 days of pregnancy. We determined the number and weight, as well as the T4 and T3 contents (RIA), of 9- to 12-day-old embryotrophoblasts, of 13- to 21-day-old embryos and placentas, and of liver, lung, and brain from 20- and 21-day-old fetuses. T4 and T3 were found in all samples obtained from C dams, both before and after onset of fetal thyroid function. Despite low levels of both iodothyronines in fetal plasma near term, their concentrations in fetal brain and lung had reached half the maternal values. The T3/T4 ratio in fetal organs was the same, or higher, than in adult rats. Maternal thyroidectomy resulted in a marked decrease of the number and individual weights of viable conceptuses, throughout gestation. Fetal organ weights near term were also decreased, and changes were found in brain DNA and protein concentrations. T4 and T3 were undetectable in all embryotrophoblasts, embryos and placentas obtained from T dams before onset of fetal thyroid secretion. They were still markedly reduced in 21-day-old placentas. Total extrathyroidal contents of T3 and T4 in 20- and 21-day-old fetuses from T dams were also low as compared to those from normal mothers, but individual organs were not affected to the same degree. Thus concentrations were decreased in the carcass (whole embryo minus the trachea + thyroid + liver + lung + brain), but normal in the brain. These results show that maternal hypothyroidism is accompanied by thyroid hormone deficiency of the conceptus before the fetal thyroid functions. After this, alterations of T4 and T3 concentrations persist until term. Development is also delayed. Thus, adverse effects of maternal hypothyroidism may be due, at least in part, to the thyroid hormone deficiency of the embryonic tissues, and not only to the hypothyroid condition of the mother.

Animals↗
PubMed1985

[Sclerodermiform porphyria cutanea tarda. Ultrastructural study].

Approximately 30% of patients affected of PCT present scleroderma-like lesion of the skin. Two cases of PCT, presenting scleroderma-like lesions are reported. The patients were diabetic but not alcoholic and tolerate relatively well sunshine. Porphyrin elimination diminished with urine alkalinization and phlebotomies, and the scleroderma-like lesions improved with N-acetyl-hydroxy-proline administration.

Aged↗
PubMed1985

[Post-phlebitis cutaneous calcinosis. Histochemical study].

A case of cutaneous localized calcinosis of the left upper limb is reported and classified as dystrophic calcinosis because the antecedent of superficial phlebitis. This kind of manifestation is rare in relationship with the frequence of superficial inflammatory processus of veins.

Adolescent↗
PubMed1984

L-thyroxine and 3,5,3'-triiodo-L-thyronine in rat embryos before onset of fetal thyroid function.

T4 and T3 have been measured by RIA in 10-12-day-old rat embryo-trophoblasts, and in 13-20-day-old embryos and placentas, as well as in a few samples of amniotic fluid. Both T4 and T3 were measured after extraction of the samples with ethanol, purification by paper chromatography, anion exchange resin, or both. T4 and T3 could be shown in all samples studied. The amounts of T4 and T3 per conceptus and their concentrations were higher in embryo-trophoblasts and placentas than in 13-18-day-old embryos. The concentrations of T4 and T3 remained fairly constant in the embryos until day 19, when they appeared to increase. The molar ratios of T4 to T3 were 1.4, 8.5 and 103 for embryos, placentas and maternal plasma, respectively. These data show that, for at least one mammalian species, embryonic tissues are provided with T4 and T3 from the earliest date studied, namely 4 days after uterine implantation, and well before onset of thyroid function, which in the rat starts after 17 days gestational age. Such a result suggests that statements denying a possible role of thyroid hormones in early embryogenesis ought to be reconsidered.

Animals↗
PubMedDate not supplied

[Costs analysis of ambulatory blood pressure monitoring in mild hypertension].

BACKGROUND: To contrast the costs of conventional and ambulatory blood pressure monitoring (ABPM) methods in the diagnosis, treatment and follow-up of mild hypertensive patients. METHODS: Among patients with conventional diagnosis of mild hypertension, the ABPM would discriminate patients with sustained hypertension, who would receive drug treatment, from patients with white coat hypertension (WCH), who would be only followed up. The diagnosis, treatment and control costs were obtained from 446 mild hypertensive patients from the Primary Health Care Center Aranbizkarra II (Vitoria, Spain) during 1996. For each gender, the overall costs per patient were estimated in both conventional and ABPM methods in terms of mean diagnosis age and WCH percentage. RESULTS: For 45 years old patients and 30% of WCH, the overall costs per patient among men were 414,999 and 371, 101 pesetas with conventional and ABPM methods, respectively. From 30 to 60 years old patients, the ABPM method turned up to be less expensive as long as the WCH percentage was higher than 6%. Similar results were obtained among women with mild hypertension. CONCLUSIONS: ABPM can be accepted as an useful clinical tool for the screening of patients with conventional diagnosis of mild hypertension. On the one hand, ABPM allows to select patients with low cardiovascular risk (WCH). On the other hand, the savings resulting from treatment reduction and fewer physician visits are higher than the additional costs of ABPM recordings.

Aged↗
PubMedDate not supplied

Ambulatory blood pressure monitoring and diagnostic errors in hypertension: a Bayesian approach.

Random variability of blood pressure complicates the diagnosis and subsequent treatment of hypertension. To evaluate the importance of the number of blood pressure measurements in the correct diagnosis and control of hypertension, the authors used a Bayesian model to estimate the true average blood pressure of a group of newly diagnosed hypertensives, then calculated the diagnostic error that would result from monitoring methods using 24 daytime measurements or from using only three random monitoring measurements. The study population consisted of 129 individuals with newly diagnosed mild hypertension according to standard criteria, who were also evaluated with an ambulatory blood pressure monitor. In true normotensives (daytime diastolic blood pressure <90 mm Hg), the negative predictive value with three measurements was 0.92, and it rose to 0.96 with monitoring methods. In mild hypertensives (90-104 mm Hg), the positive predictive value was 0.64 with three measurements and 0.84 with monitoring methods, thus reducing the rate of false mild hypertensives from 35% to 15%. Finally, in patients with moderate or severe hypertension (>104 mm Hg), the positive predictive value improved from 0.26 with three readings to 0.61 with monitoring methods. Similar results were observed with daytime systolic pressure measurements. As the number of measurements increased, the diagnostic error due to the random variability of blood pressure became progressively smaller. In cases of hypertension, the large improvement in predictive values may justify using monitoring methods to confirm standard diagnosis.

Adult↗