PubMed Health⌕ Search

Biomedical subjects

C Osorio

Publications and source records attributed to C Osorio.

At least 37 records · Page 2Linked to original sources
PubMed1984

Role of pineal gland in kidney-adrenal homeostasis.

The effects of pineal gland on kidney-adrenal axis have been studied in male rats. Rats were pinealectomized and exposed to a photoperiod of 12 h light: 12 h dark. Plasma renin activity (PRA), corticosterone and corticotropin (ACTH) levels were measured at 10, 20 and 35 days postpinealectomy. Pinealectomy increased corticosterone and ACTH levels and decreased PRA in all age groups. A significant negative correlation was found between corticosterone and PRA, which suggest that changes in PRA were due to changes in circulating corticosterone, via feedback mechanism on renin secretion. On the other hand, melatonin administration prevents these effects of pinealectomy. It is suggested that the lack of this pineal indol is responsible for the pinealectomy-induced alterations in male rats.

Adrenal Glands↗
PubMed1984

Effects of sulpiride on levels of FSH, LH and steroid hormones.

In order to study the effects of prolactin upon the gonadotrophins and steroid hormones, hyperprolactinaemia was induced by the administration of sulpiride. 12 men between the ages of 18 and 20 were given 3 capsules of 50 mg of sulpiride daily for a period of 15 days, and the following parameters being measured before and after the treatment: (prolactine, FSH, LH, testosterone, estradiol, ACTH and DHEA-S) by RIA, (cortisol) by fluorimetry and (etiocholanone, androsterone, pregnandiol, pregnantriol, pregnantriolone, 11-keto etiocholanone and 11-OH androsterone) by gas chromatography. Our results show that on termination of the treatment there was a significant rise in the prolactin and DHEA-S serum levels and a drop in the FSH serum levels but not of LH. In addition there was a marked increase in all the androgen levels studied, (etiocholanone, androsterone and 11-keto etiocholanone) with the exception of testosterone.

Adolescent↗
PubMed1983

Afferent pathways to points of self-stimulation in the medial prefrontal cortex of the rat as revealed by the horseradish peroxidase technique.

Afferent projections to points of self-stimulation (SS) in the medial prefrontal cortex (MPC) of the rat were studied using the horseradish peroxidase (HRP) technique. Intracranial microinjections of HRP (30%) were delivered at the same stereotaxic points at which the electrodes eliciting SS were located. Retrogradely transported HRP labeled neurons in different thalamic, hypothalamic, mesencephalic and pontine areas. In the thalamus, labeled neurons were found in the dorsomedial, anteromedial, anteroventral, ventral, ventromedial, posteromedial, paratenial, parafascicular nuclei and n. reuniens. Labeled neurons in mesencephalic areas were found in the n. interpeduncularis, ventral tegmental area (AVT) and substantia nigra (SN). In the pons, labeled neurons were found in the locus coeruleus and in the periaqueductal gray. Other nuclei in which labeled neurons were also found were: lateral hypothalamus (LH), periventricular gray and zona incerta (ZI). Theoretically it is possible that all these afferent areas contribute to SS of MPC. This assumption is discussed and criticized in connection with previous literature on SS. It is suggested that only specific areas and their projections are good candidates for the neural mechanisms involved in the reward produced by electrical stimulation of the prefrontal cortex.

Afferent Pathways↗
PubMed1983

Putative amino acid neurotransmitters and the nucleus dorsomedialis thalamus-prefrontal cortex pathway in the rat.

Endogenous levels of putative amino acid neurotransmitters (glycine, glutamic acid, aspartic acid, and GABA) in medial and sulcal prefrontal cortex of the rat were analyzed using gas liquid chromatography. No changes were found in the levels of these amino acids in medial and sulcal prefrontal cortex after lesion of the nucleus dorsomedialis of the thalamus suggesting, therefore, that the NDMT-prefrontal cortex pathway is not mediated by these amino acids.

Amino Acids↗
PubMed1983

Monoamines and self-stimulation of the medial prefrontal cortex in the rat.

The participation of noradrenaline (NE) and serotonine (5-HT) in self-stimulation (SS) of the medial prefrontal cortex (MPC) in the rat has been studied. Three groups of rats with bilateral electrodes implanted into the MPC were used in these experiments. In one of the groups, electrodes were also implanted into the locus coeruleus. In the first group, the rats received systemic injections of the following drugs: clonidine (alpha-agonist), phenoxybenzamine (alpha-antagonist), isoproterenol (beta-agonist) and propranolol (beta-antagonist). In the second group, p-chlorophenylalanine (a 5-HT synthesis inhibitor) was administered intragastrically and SS measured during the following 16 days. In these two groups of rats and previous to every SS session, spontaneous motor activity (SM) was measured as control for non specific effects of the drugs. In a third group of rats, lesions of the locus coeruleus were performed unilaterally and SS measured in both prefrontal cortex during the following 16 days post-lesion. SS contralateral to the lesioned side served as control for non-specific effects of the lesions. After all these treatments, SS of the MPC was not specifically affected. Our results suggest the non participation of NE and 5-HT terminals in the neural substrates underlying SS of the MPC.

Adrenergic alpha-Antagonists↗
PubMed1983

LHRH test in ovariectomized women with and without treatment of sex hormones.

The modulatory effect of sex hormones on the LHRH test, has been studied on ovariectomized women, randomly divided into groups which received estrogen (E2), progesterone (P) and E2 + P respectively. One group was left untreated. Menstruating women in follicular phase were also studied. The LHRH test was performed on all women and FSH, LH levels were measured in the blood. The LH levels in the blood following the LHRH test showed an increase in all the groups under investigation, including the ovariectomized untreated one. This suggests that, after ovariectomy, the hypophysis does not reach its maximum capacity for gonadotrophin release. The FSH response to the LHRH test was very low in all the groups studied, including the ovariectomized without treatment. It thus could be suggested that FSH needs other stimuli besides LHRH for its physiological release.

Adult↗
PubMed1982

Calcium and renin release: inhibition of low sodium-induced renin secretion by high calcium concentration in rat kidney perfusion.

The effects of changes in calcium on renin secretion have been studied in the isolated perfused rat kidney. Perfusion with free calcium buffer significantly decreases renin secretion as compared with control experiments (Ca++: 2.5 mM/l). Other calcium concentrations (1.25 mM/l) and 5 mM/l) do not affect basal renin secretion. When the renin release is previously increased by low sodium concentration (Na+: 110 mM/l) however, perfusion with high calcium buffer (Ca++: 5 mM/l) significantly inhibits this stimulation.

Animals↗
PubMed1982

Increased activity of the renin-angiotensin-aldosterone system during the perinatal period.

Plasma renin activity (PRA), plasma renin substrate (PRS), plasma renin concentration (PRC), and plasma aldosterone concentration (PAC) were measured in normal full-term newborn infants and infants up to 22 days after birth (36 in all). As compared to the control, PRA and PAC levels were significantly higher (p less than 0.001) in cord blood, and in 2 to 6 and 12 to 22 day old infants. The high values of PRA in 2 to 6 day old infants were due to the high PRS values. In cord blood and in 12 to 22 day old infants, however, the high levels of PRA reflect elevation of PRC. No correlation was found between PRA, PAC and serum potassium in cord blood and in 2 to 6 day old infants, but there was a significant correlation between the parameters (r = 0.72 and p less than 0.02) in 12 to 22 day old infants, indicating that at this age, as in healthy adults, the renin-angiotensin system and serum potassium seem to be the major stimuli for aldosterone secretion.

Adult↗
PubMed1982

Inhibition of the renin-angiotensin system by pinealectomy in female rats.

The influence of the pineal gland on the renin-angiotensin system has been studied in female rats. Pinealectomy produces a decreased plasma renin activity (PRA) concomitant with an increased corticosterone level, and with no changes in plasma aldosterone. Administration of indol melatonin reverses the effects of pinealectomy. On the other hand ovariectomy induces an increased PRA while decreasing corticosterone and aldosterone levels. However when pinealectomy and ovariectomy are both performed, neither PRA nor corticosterone changes. These results suggest that the pineal gland may exert an influence on the renin-angiotensin system via adrenal and/or ovarian pathways.

Aldosterone↗
PubMed1982

Inorganic phosphate-insulin relationships in normal subjects and in patients with moderate glucose intolerance.

The relationship between serum insulin and serum inorganic phosphate levels was investigated in normal subjects (NGT) and in patients with moderate impairment of glucose tolerance (IGT1 with subnormal and IGT2 with excessive insulin secretion) fasting and after oral glucose. Insulin and phosphate fasting levels were similar in all groups. In NGT subjects, a significant correlation between fasting insulin and inorganic phosphate levels are observed. In NGT and in IGT1 subjects, oral glucose administration was followed by a fall in serum phosphate level that was well correlated with the total insulin released. The phosphate fall was severely impaired in IGT2 patients, despite the increased insulin secretion. The plasma ionized calcium levels remain unchanged throughout the OGTT. The present results support the hypothesis that in IGT1 patients a reduced glucose-induced insulin release and in IGT2 patients, a peripheral resistance to insulin action could be the determinant of impaired glucose tolerance.

Adult↗
PubMed1981

Effect of insulin on acetate metabolism in chicken adipocytes.

The effects of insulin on the metabolism of acetate-U-14C in isolated chicken adipocytes have been investigated. Insulin added in vitro at physiological concentrations did not stimulate the incorporation of acetate-U-14C into triglycerides or CO2 when the acetate was present alone. In the presence of glucose 11m M, however, insulin stimulated significantly lipogenesis from acetate. This is an indirect action mediated by glucose.

Acetates↗
PubMed1981

Immunogenetic studies of H-2 antigens of MCG 3 tumour cells.

MCG 3 is a B 10(H-2b) sarcoma induced as a solid tumour with 0.2 mg of methylcholantrene in our laboratory. The ascites form obtained was used to study the expression of H-2 antigeneic specificities in a postlabelling radioassay. H-2D.2, H-2K.33 (private specificities of H-2b) and H-2.28, H-2.35 (public specificities) were normally expressed for MCG 3 while H-2.5, H-2.29, H-2.36 (public specificities) were abnormally absent. These results were confirmed by quantitative absorption analysis using MCG 3 and positive-negative normal lymphoid cells for a particular specificity.

Animals↗
PubMed1980

Effect of insulin in vivo on the synthesis of free fatty acids (FFA) in chicken heart and skeletal muscle.

The effect of insulin on the synthesis of free fatty acids from glucose in the skeletal and heart muscles of chicken is examined. 10 min after glucose-(U-14C) administration, labeled free fatty acids (FFA) appeared in both skeletal and heart muscles. 0.75 IU of insulin kg-1 b. wt significantly increased the labeled FFA at the 30, 60 and 120 min intervals, with a maximum at 60 min.

Animals↗
PubMed1980

The effect of orthostatism, passive tilting and recumbent exercise on renin release.

Three postural tests, orthostatism, passive tilting and recumbent exercise, were applied to fourteen normal volunteers. Orthostatism and tilting produce a significant increase in plasma renin activity (PRA) and plasma renin concentration (PRC), without changes in plasma renin substrate concentration (PSC). Recumbent exercise induces an inhibition of PRA and PRC and does not changes PSC. The present study seems to suggest that sympathetic activity and intravascular blood volume could play an important role in the responses of the renin-angiotensin system to postural changes.

Adult↗
PubMed1980

A comparative study between Fc receptor bearing cells and antibody dependent cell cytotoxicity in cancer patients.

The capacity of 14 cancer patients lymphoid cells to destroy antibody-coated target cells (antibody-dependent cell cytotoxicity ADCC), and to form rosettes with immunoglobulin-coated erythrocytes (EA) was compared. The lymphocyte functions were investigated immediately prior to chemo-immunotherapy. Our observations show a correlation between the percentage of EA-rosette forming cells and ADCC activity of cancer patients and controls. However, the regressive lines were different in both groups. Interestingly, cancer patients with a lower. EA rosette forming cells than controls, showed higher cytotoxic activity.

Adult↗