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Biomedical subjects

B Díaz

Publications and source records attributed to B Díaz.

35 records · Page 2Linked to original sources
PubMed1995

Maternal pineal gland participates in prepubertal rats' ovarian oocyte development.

BACKGROUND: Sexual maturation is a very complex phenomenom that it is mediated by the ontogeny of the hypothalamus-pituitary-gonadal axis during intrauterine life. The maternal pineal gland can affect fetal development because the main pineal hormone, melatonin, crosses the placental barrier. We found that melatonin treatment during gestation in the rat produced delayed sexual maturation of the female offspring. The present work was undertaken to study the maturational stage of oocytes of prepubertal female rats when their mothers were either pinealectomized (PIN-X) or treated with melatonin (MEL) during pregnancy. METHODS: Three groups of female Wistar rats were used: control, PIN-X, and those treated (250 micrograms/100 g body weight) with melatonin throughout pregnancy. Ovaries of 25-30- and 34-day-old female offspring were studied during the prepubertal phase. Morphometric studies of semithin sections (1 micron) of the ovaries were performed. Oocyte, nuclear, and nucleolar volumes were calculated by a computer-assisted program (M.I.P.) in an image analyzer Kontron. Regularity of the structures was determined by the frequency distributions of circular and regular form factors. RESULTS: Cytometric study of oocyte structure showed a frequency distribution of regular and circular form factors, with a high degree of regularity very close to unit. Cellular and nuclear volumes of follicular oocytes showed a transitory increase at 30 days of age in control rats. In the offspring of MEL-treated mother rats, a pattern of oocyte development showed significantly lower nuclear and nucleolar volumes at 30 days of age than at the other time points and significantly lower cellular volume at 34 days of age than at 25 days of age. In the offspring of PIN-X mother rats, no significant differences in oocyte cellular volumes were observed throughout prepubertal development, but we observed a significantly higher nuclear volume at 25 days of age and a significantly lower nucleolar volume at 30 days of age. CONCLUSIONS: These findings show that the maternal pineal gland participates in cellular and nuclear volumes of prepubertal oocyte development. Melatonin treatment during pregnancy resulted in a redirected postnatal oocyte development.

Animals↗
PubMed1993

[The ICD-10 and mood disorders].

30 patients with affective disorders are evaluated by a Mental Health team following diagnostic criteria of ICD-10 and DSM-III-R. Results are compared. Significative aspects of ICD-10 and differences between both classifications are analyzed in this area.

Adult↗
PubMed1993

Melatonin and gonadotropin hormones in pubertal sportsgirls.

In order to determine the influence of physical training on menstrual disturbances in sportsgirls, the levels of luteinizing hormone (LH), follicle stimulating hormone (FSH) and melatonin have been studied in young athletes of track and field speciality using the Cooper test. Basal hormone levels and anthropometric data were also studied in age matched control girls. No significant differences in LH, FSH and melatonin hormone concentrations were observed between the PRE and POST Cooper test. However, significantly lower basal levels of LH were found in the early follicular phase or luteal phase of sportsgirls when contrasted with the control girls. No differences in FSH levels were observed in the early follicular phase of sportsgirls but higher FSH levels were found in the luteal phase. Daytime melatonin levels of sportsgirls were significantly higher than those in control girls. Age and anthropometric parameters studied showed no differences in height, weight, tricipital skinfold and percentage of body fat, but abdominal and subescapular skinfold measures were greater in control girls than in sportsgirls. It appears that continuous physical training can produce alterations in antireproductive hormone secretion such as melatonin, which can play an inhibitory role on the menstrual cycle hormone patterns in sportsgirls.

Adolescent↗
PubMed1991

Melatonin administration during pregnancy retards sexual maturation of female offspring in the rat.

The influence of pineal gland function and of melatonin during pregnancy upon sexual maturation of female offspring in rats was examined. The following groups of Wistar rats were studied: (A) control, (B) melatonin treated (250 micrograms/100 g.b.w. per day) throughout pregnancy, and (c) pinealectomized (pin-x). Melatonin was injected subcutaneously 2 hr before lights off. All groups were housed in 12-hr L:12-hr D. The female offspring were observed until the onset of puberty, and blood samples were collected 5.5 hr after lights off under red light for melatonin and LH determinations by RIA. Ovary, pineal, and pituitary gland as well as body weights were recorded. The offspring of melatonin-treated rats showed later vaginal opening than did those of the other two groups (P less than 0.05 vs. control and P less than 0.01 vs. pin-x offspring), which was accompanied by a lower LH concentration, 0.42 + 0.05 ng LH/ml, showing statistically significant differences with the control levels [1.00 + 0.22 ng LH/ml (P less than 0.05)] and with the pin-x group [1.16 + 0.22 ng LH/ml (P less than 0.05)]. The percentage of rats in proestrus was higher in the offspring of pin-x rats (78.6%; P less than 0.01) compared to control offspring (30%) and offspring of melatonin-treated rats (11.8%). The concentrations of melatonin, 5.5 hr after darkness, were not significantly different among groups. No differences were observed in the body, ovarian, and pineal weights of the studied offspring. The pituitary weight was significantly lower (P less than 0.05) in the offspring of pin-x rats than in the other two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[Hyperaluminemia and parathormone release].

Previous studies have shown that aluminum (Al) could inhibit parathyroid function. However, controversy still remains about the possible mechanisms implicated. Thus, the aim of this study was to evaluate the acute parathyroid hormone (PTH) response to intravenous Al infusion. Male Wistar rats were divided into two groups: Group A (n = 5): received 0.1 ml of saline. Group B (n = 5): received 0.5 mg of Cl3Al in 0.1 ml of saline. In both groups ionized calcium (Ca(+)+) decreased, but despite a similar degree of haemodilution, this change was only significant in group A. This variable Ca(+)+ decrease was followed by different responses in the PTH secretion. In group B there was a significantly (p less than 0.05) lower PTH release compared with control group. These results suggest that Al could directly inhibit the PTH secretion, and at the same time might exert an indirect effect on PTH release "blunting" the serum Ca(+)+ variations.

Aluminum↗
PubMedDate not supplied

Prenatal melatonin exposure influences the maturation of gonadotropin and prolactin estradiol-benzoate feedback system.

Gonadotropin and prolactin response to estrogen feedback in female rat offspring of control and melatonin treated (150 microg/100 g BW) mother rats during pregnancy (MEL-offspring) were studied at these periods: infantile, prepubertal and pubertal. In controls negative or absent LH feedback developed after estradiol benzoate (EB) injection up to 30 days of age indicating that the onset of puberty had not occurred. The positive feedback was established from day 33 on. However, in MEL-offspring the first activation of gonadotropin secretion during afternoon, 31 h after EB, was observed at 25 days of age, representing the first neuroendocrine sign of the onset of puberty. This positive response disappeared on day 30 in MEL-offspring. At 33 days of age, the LH positive response to EB was found in both groups, indicating a more advanced sexual development. In controls, this response increased at 35 days of age while in MEL-offspring it was highly depressed. FSH secretion in response to EB showed a negative feedback effect from infantile to the end of prepubertal period in both groups. The positive feedback was observed earlier in MEL-offspring (at 33 days of age) than in controls (at 35 days of age), but at this age it was absent in MEL-offspring. A positive prolactin response to EB at all ages in controls was observed. The typical pulsatility with higher values in the afternoon appeared by the first time at 30 days of age. However, in MEL-offspring no pulsatile response was observed throughout any age. These data suggest that prenatal melatonin administration altered gonadotropin and prolactin response to EB inducing precocious sensitivity during prepubertal period but depressed response during the pubertal period.

Animals↗
PubMedDate not supplied

Effect of prenatal melatonin on the gonadotropin and prolactin response to the feedback effect of testosterone in male offspring.

The purpose of this study was to investigate the effects of prenatal melatonin administration on the sensitivity of the androgens negative feedback effect on gonadotropin and prolactin secretion in male offspring. Male offspring of control (control-offspring) and melatonin treated (MEL-treated) (150 microg/100 g BW) mother rats during pregnancy (MEL-offspring), at infantile, prepubertal, and pubertal periods were studied. LH secretion in response to testosterone propionate (TP) in control-offspring showed the classical negative feedback effect at all ages studied. In MEL-offspring a negative response after TP was also observed in all ages studied although the magnitude of this response was altered in this group as compared to controls. FSH values were significantly lower at most ages and time points studied in MEL-offspring than in control-offspring. FSH secretion in MEL-offspring showed a delayed negative feedback action of TP injection as compared to control-offspring. This response was observed at 21 days of age in control-offspring and delayed until day 30 of life in MEL-offspring. Parallely it remain at later age in MEL-offspring than in control-offspring. Prolactin secretion in control-offspring showed increased values after TP injections from infantile to pubertal periods. This increase was blunted in MEL-offspring at 17 and 35 days of age showing significantly reduced (p<0.01; p<0.05) plasma prolactin levels. During pubertal period a prolactin positive response to TP administration was observed in MEL-offspring but with significantly lower magnitude than in control-offspring. These results indicate that prenatal melatonin exposure induced changes in the sensitivity of gonadotropin and prolactin feedback response to testosterone, indicating a delayed sexual maturation of the neuroendocrine-reproductive axis in male offspring.

Aging↗
PubMedDate not supplied

Extraperitoneal laparoscopic para-aortic lymphadenectomy for lymph node recurrence of fallopian tube carcinoma.

The endoscopic retroperitoneal approach is a minimally invasive method for surgical staging of cervical cancer. A 57-year-old woman had an intraoperative diagnosis of carcinoma of the left fallopian tube and undergone a retroperitoneal pelvic and para-aortic lymphadenectomy with no peritonization during surgical staging. Small suspicious nodes in the serous membrane of the sigmoid colon and peritoneal washings were positive for malignancy. A total of 12 nodes were obtained, all of which were negative. She received six cycles of paclitaxel and platinum-based chemotherapy and showed a complete clinical response. Thirty-two months after surgery, the abdominal computed tomography scan showed a left para-aortic lymph node, 19 mm in diameter, which was successfully removed through an extraperitoneal laparoscopic approach. The extraperitoneal laparoscopic approach of the para-aortic region is a feasible procedure after previous transperitoneal lymphadenectomy and chemotherapy.

Carcinoma↗
PubMedDate not supplied

Hypothyroidism and primary open-angle glaucoma.

OBJECTIVE: To test if there is an association between hypothyroidism and primary open-angle glaucoma (POAG) and the utility of routine study of thyroid function in these patients. METHODS: The study was conducted in a case-control fashion. Seventy-five consecutive patients with a previous diagnosis of POAG and 75 control patients were prospectively evaluated for hypothyroidism. The levels of thyroid-stimulating hormone and free thyroxin were measured. RESULTS: Hypothyroidism was revealed in only 2 patients with previous diagnosis of POAG (2.67%) and 3 patients of the control group (4%). CONCLUSIONS: As we have not been able to demonstrate the previously reported relationship between hypothyroidism and POAG, we cannot recommend the systematic screening for hypothyroidism in patients with POAG.

Adult↗
PubMedDate not supplied

Hepatitis B virus exposure in human immunodeficiency virus seropositive Cuban patients.

In order to estimate the prevalence of serological markers of exposure to Hepatitis B Virus (HBV), 295 subjects were selected at random from the National Registry of human immunodeficiency virus positive subjects. Evidence of exposure to HBV was defined as: testing Hepatitis B surface antigen (HBsAg) and anti-Hepatitis B core antigen (anti-HBc) positive or anti-HBc positive only. Overall, 133 (45.5%) were positive for anti-HBc and 15 (5.1%) resulted positive to HBsAg. Significant statistical association was found between male sex and exposure to HBV (p<0.01). Homosexual or bisexual behavior was found to be strongly associated to HBV exposure (p<0.001). In conclusion, the prevalence of HBV serological markers is higher in Cuban HIV positive subjects compared to the Cuban general population.

Adolescent↗