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Biomedical subjects

A Zarate

Publications and source records attributed to A Zarate.

At least 19 recordsLinked to original sources
PubMed2001

Insulin-like growth factor I, epidermal growth factor and transforming growth factor beta expression and their association with intrauterine fetal growth retardation, such as development during human pregnancy.

AIM: Fetal intrauterine growth retardation (IUGR) is one of the most common obstetric problems, with a frequency of 12% in Mexico. In the past, investigations have focused on extrinsic causes of IUGR. More recent studies have examined the intrinsic factors that cause fetal intrauterine growth. Maintenance of fetal growth has been attributed to insulin-like growth factor (IGF), epidermal growth factor (EGF) and transforming growth factor beta (TGF-beta). The objective of this study was to assess the levels of these growth factors during pregnancy and to determine whether or not low concentrations are associated with IUGR. METHODS: Nine women whose pregnancies were complicated by IUGR and a group of nine women whose pregnancies exhibited normal fetal intrauterine growth were studied. IUGR was determined by sonography and confirmed by weight at birth. Venous blood samples were taken from both groups of pregnant women at the end of each trimester. Enzyme-linked immunosorbent assays, immunoradiometric assays and radioimmunoassays were used to process samples, and the results were analysed by anova. RESULTS: IGF-I levels increased in both groups during pregnancy, but the increase was lower (p < 0.001) in the IUGR group throughout pregnancy and at delivery. EGF did not show any significant changes during pregnancy. Blood TGF-beta levels varied only during the first trimester of pregnancy. The differences were not statistically significant. However, TGF-beta concentrations were higher in the pregnancies with IUGR. Women in the IUGR group were smaller than in the control group (p < 0.05), and, using the covariance test (p < 0.05), this was found to be correlated with IGF-I levels but not with EGF or TGF-beta levels. CONCLUSIONS: Changes in fetal weight might be explained by the different concentrations of IGF. The structural homology between IGF-1 and insulin could mean that the presence of higher levels of IGF would result in a increased energetic metabolism that could contribute to fetal growth. EGF levels were not related to IUGR, and TGF-beta levels increased only during the first 3 months in the IUGR group. This observation correlates with the in vitro action of TGF-beta as a negative factor of growth, but as a positive support for sustaining early pregnancy. Our data illustrates that low height represents an increased risk factor for IUGR. These data also correlate with the studies involving extrinsic factors.

Adult↗
PubMed1999

Differential effects of octreotide treatment and transsphenoidal surgery on growth hormone-binding protein levels in patients with acromegaly.

OBJECT: The high-affinity growth hormone-binding protein (GHBP) represents the extracellular portion of the growth hormone (GH) receptor, and its serum levels are a reflection of the tissue receptor status. Levels of GHBP are decreased in patients with active acromegaly, probably because of downregulation of GH receptors. However, there are no studies of patients with acromegaly in which the effects of medical (that is, administration of somatostatin analogs) and surgical therapy on GHBP levels have been compared. That is the task the authors set out to accomplish in this study. METHODS: The authors studied seven patients in whom acromegaly had been recently diagnosed. They examined these patients at baseline, 2 months after octreotide treatment (subcutaneous administration of 100 microg octreotide three times per day), and 1 month after transsphenoidal surgery. Growth hormone-binding activity was measured, as well as the following biochemical markers of the somatotropic axis: GH suppression induced by oral administration of glucose, insulin-like growth factor-I (IGF-I), and insulin-like growth factor-binding protein-3 (IGFBP3). Although octreotide treatment induced a decrease in the levels of GH, IGF-I, and IGFBP3, as well as an increase in the level of GHBP, these biochemical markers did not reach normal levels. On the other hand, after transsphenoidal surgery, GHBP levels became normal, particularly in those patients in whom serum GH could be suppressed to an undetectable level after glucose loading. CONCLUSIONS: The authors conclude that persistently low GHBP levels in patients with acromegaly are normalized by successful pituitary surgery and correlate well with disease activity.

Acromegaly↗
PubMed1996

[Variations in the molecular forms of LH and FSH during the normal ovarian cycle].

FSH and LH concentrations during the menstrual cycle are well known, showing characteristically a midcycle surge in LH as well as in less degree in FSH. At the present there is an increasing interest in studying variations of the moleculoar forms of both gonadotropins. We have studied the chromatographic profile of FSH and LH in sera obtained from women regularly ovulating and in patients with anovulatory cycles by the use of gel column chromatography. It was observed the predominance of LH 32-34 kDa at midcycle and the heterogeneous FSH profile during the ovarian cycle. In sera from anovulatory patients the chromatographic profile was even more irregular for both LH and FSH. It is concluded that LH 32-34 kDa may be the more biological isoform in turn related with the process of ovulation.

Adult↗
PubMed1996

[Clinical trial with tibolone in postmenopausal replacement therapy].

Estrogen deficiency is the basic change in women around the climateric stage. This hormone deficiency is different among women regarding the age and intensity of symptoms. The hormone replacement has proved its benefit on relieve of symptoms and long term effect on prevention of cardiovascular disease and osteoporosis. A new pharmacological agent Tibolona has been studied recently as replacement therapy. This work reports the results obtained with the use of Tibolona in 36 postmenopausal women. The effectiveness and security were confirmed as well as the low occurrence of side effects. It was also apparent that this therapy had a relevant effect on the psycho-emotional component and upon the improvement of sexual satisfaction and activity.

Adult↗
PubMed1991

Diabetes mellitus in Mexico.

Diabetes in Mexico is a public health problem with considerable medical, social, and economic consequences. Although detailed data on the prevalence of diabetes and its complications are not available, health services utilization data of the Social Security organization (Instituto Mexicano del Seguro Social) indicate increasing use of primary and tertiary care for diabetes over a recent 10-yr period. A health interview survey conducted in 1988 indicated that, in different areas, from 3.5 to 12.7% of people aged greater than or equal to 65 yr are believed to have diabetes, and that rates are higher in many of the states bordering the United States. Diabetes ranks among the leading 10 causes of death throughout the country. Although the ranking varies from state to state and the diagnosis may not appear on the death certificate when death results from a complication of the disease, in 1983 diabetes was the leading cause of death in Mexico and the first or second leading cause in many of the states bordering the U.S. Gestational diabetes contributes to perinatal mortality, and in view of the high birth rates, represents an important facet of the disease in Mexico. The impact of specific complications of diabetes on morbidity and mortality in Mexico are not well delineated. The relative frequency and impact of insulin-dependent and non-insulin-dependent diabetes in Mexico are not known.

Adolescent↗
PubMed1987

Long-acting bromocriptine for the acute treatment of large macroprolactinomas.

Six patients with hyperprolactinemia, visual impairment and large macroprolactinoma were treated with a long-acting bromocriptine, in dosage of 50 mg as a single im injection. All patients underwent a full assessment of pituitary prolactin (PRL) secretion before treatment and the studies were repeated about every week during 40 days. Following bromocriptine injection a rapid amelioration of the clinical and visual defects occurred in all patients. Likewise, a significant reduction of the hyperprolactinemia was documented in all six patients and in three of them serum PRL levels reached values as low as 20 ng/ml, and a tumor size reduction was demonstrated by cranial computerized tomography in three of the six cases. No side effects were associated with the administration of bromocriptine. From this study we conclude that the long-acting bromocriptine represents an additional option for the initial management of large prolactinomas in particular when they are associated with severe visual impairment.

Bromocriptine↗
PubMed1987

The significance of elevated levels of gastrin in patients with pituitary adenoma.

Six patients were studied with pituitary adenomas and elevated concentrations of gastrin similar to those found in cases of benign antral gastrinoma syndrome. Chromatography of the serum using Sephadex-G50 revealed different molecular forms of gastrin according to the type of adenomas. In those cases of acromegaly and gonadotrophinoma, gastrin-34 and unsulphated gastrins constitute the predominant forms. In contrast, in cases of Cushing's disease, gastrin-17, sulphated as well as non-sulphated were the predominant types; the chromatographic pattern was similar to that observed in two patients with antral gastrinoma syndrome who acted as controls. These findings demonstrate that pituitary adenomas might secrete gastrin. Taking into account that gastrin-34 and unsulphated gastrins were the predominant forms in cases of acromegaly, gonadotrophinoma and non-functioning adenoma, it is assumed that those molecular forms are mainly produced in the anterior lobe of the hypophysis. Conversely, gastrin-17 was the principal molecular form in cases of Cushing's disease confirming the close relationship of the synthesis of gastrin and corticotrophin peptides. The cases with Cushing's disease exhibited a serum gastrin pattern similar to that observed in the two cases with antral syndrome in which the predominant immunoreactive form of gastrin in gastrin-17 exhibiting a degree of sulphation corresponding to that of antral gastrin. It is concluded that the circulating excess of gastrin originated in the pituitary tumour tissue and the molecular form varied with the type of pituitary adenoma.

Adenoma↗
PubMed1981

Anovulatory effect of a LHRH antagonist in women.

The antagonistic analog of LHRH, NAc-D-p-Cl-Phe(1),(2), D-Trp(3),D-Phe(6), D-Ala(10)-LHRH was administered intramuscularly in a dose of 2 mg to ten normally ovulating women on day 12 of the menstrual cycle. Ovulation was inhibited in six patients, and two more presented an insufficient corpus luteum. No pregnancies were recorded in this series. In those patients who did not ovulate, it was demonstrated that the LHRH analog abolished the midcycle surge of both LH and FSH. Luteolysis evidenced by the rapid decline in progesterone levels was present in 2 cases. Bleeding pattern showed a tendency to delayed menses. The morphological findings in endometrial biopsies of 6 women exhibited mild proliferation. Further research along these lines is necessary for appraisal of this approach to birth control.

Adult↗
PubMed1981

Propranolol-associated hypoglycemia in patients on maintenance hemodialysis.

Propranolol is widely employed in hemodialysis patients for the control of renin-dependent hypertension. Infrequent reports have linked hypoglycemia and propranolol, especially in complex situations such as malnutrition, anesthesia, and excessive insulin use. Three patients on maintenance hemodialysis taking propranolol developed severe hypoglycemia resulting in cardiac arrest. The life-threatening hypoglycemia occurred without apparent precipitating cause and unaccompanied by the classical signs and symptoms of hypoglycemia. These three cases suggest that propranolol in a setting of chronic renal failure and dialysis may bring about severe hypoglycemia, a complication previously unsuspected.

Adult↗
PubMed1980

Pericardial effusion associated with minoxidil therapy in dialyzed patients.

Pericardial effusion, diagnosed clinically or by echocardiography, was found in 13 of 16 regularly dialyzed patients (81%) receiving minoxidil for refractory hypertension. In a comparable group of 125 patients not receiving minoxidil, 28 patients (23%) had evidence of pericardial effusion, the difference between the groups being highly significant (p less than 0.0005). In minoxidil treated patients, the effusions resolved spontaneously in 4 (3 remaining on treatment), required pericardiocentesis (3), or pericardiectomy (1), and persisted in 4 (3 remaining on treatment). It is suggested that minoxidil treated dialysis patients be regulary examined for the development of potentially threatening pericardial effusions.

Adult↗
PubMed1977

[Gonadotropin reserve in anorexia nervosa].

Four patients with anorexia nervosa were studied. All patients in the acute stage of the illness had low serum luteinizing hormone (LH) levels which were unresponsive to clomiphene. The four women showed almost no LH response on a single iv injection of 100 mug LH-RH; however, the FSH response was similar to that of normal eumenorrheic women. When the patients had regained weight the LH levels were normal, and they responded normally to LH-RH. These results seem to suggest that impaired hypothalamic function is the cause of gonadotropin deficiency in most patients with anorexia nervosa.

Anorexia Nervosa↗
PubMed1976

Triple X female and Turner's syndrome offspring.

A mentally retarded young female having 47 chromosomes with a triple X karotype produced a child with Turner's syndrome associated with mental defeciency. To our knowledge this is the first example of a triple X female giving birth to a child with Turner's syndrome.

Adult↗
PubMed1976

The effect of oral administration of thyrotropin-releasing hormone on lactation.

Sixteen puerperal women between the ages of 17-30 years, were studied in a double blind trial during the four weeks postpartum. Eight women received orally 20 mg of synthetic TRH three times a day, 30 minutes before the corresponding breast feeding; the remaining group received a placebo in the same fashion. The women receiving TRH exhibited higher basal concentrations of serum PRL as well as a higher increment in response to suckling; however, the PRL concentrations before and after breast feeding in this group were similar to those of the control group by the fourth week postpartum. TRH treatment showed no effect on the yield or content of milk during the four-week period. In a conjoint study, PRL concentrations did not rise after TRH administration in women with defective lactation, suggesting that some impairment of the PRL release mechanism was present. TRH caused no clinical hyperthyroidism in the mothers nor in the children. Serial determinations of serum T3 and TBG revealed values within the normal limits. It was also observed that TRH administration had no effect on FSH and LH secretion, and gonadotropin secretion was not inhibited despite of the increments on PRL concentrations. In both groups, suckling had no effect on serum levels of pituitary gonadotropins determined before and after breast feeding. We have concluded that in full lactating mothers: a) the oral administration of TRH produced a marked increment in PRL concentration but no significant augmentation of milk production was observed; b) in some cases of hypogalactia, TRH did not improve the milk production; and c) the PRL-enhanced secretion showed no effect on gonadotropin secretion.

Administration, Oral↗
PubMed1976

Serum FSH and synthetic LHRG response in pregnant women at term and in the newborn.

Serum immunoreactive FSH was undetectable in a) pregnant women past 38 weeks of gestation, b) newborn infants, and c) anencephalic infants. The intravenous administration of 100 mug of synthetic LHRH elicited no FSH release in each instance. These results seem to indicate that the absence of FSH in serum in pregnant women in the last trimester, as well as in the newborn, is due to the suppressive effect on the anterior pituitary of the increased amount of circulating sex steroids.

Anencephaly↗