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Biomedical subjects

A Parra

Publications and source records attributed to A Parra.

At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

A computerized system for learned helplessness experiments.

A microcomputer-based system for carrying out learned helplessness experiments is described. The hardware is inexpensive and easily available. The program is written in BASIC and must be executed in the compiled form in order to keep up with real-time events. It contains an algorithm for calculating inter-trial intervals and allows the experimentor to freely select experimental conditions such as duration of shock, number of trials, etc. The task that the rat is required to do to stop the shock is also selectable, thus giving the experimentor the opportunity to maximize behavioral differences between escapable and inescapable rats while these differences are being induced. Experimental data on 12 rats that went through this automated protocol are analyzed and discussed.

Analysis of Variance↗
PubMedDate not supplied

Hypothalamic dopaminergic tone and prolactin bioactivity in women with polycystic ovary syndrome.

BACKGROUND: The present study was carried out to investigate the functional significance of the reduced dopaminergic tone in subjects affected with polycystic ovary syndrome (PCOS). METHODS: Our group evaluated the response of pituitary PRL, LH, FSH, and TSH to the administration of a single 10-mg oral dose of the dopamine (DA) receptor antagonist metoclopramide in lean (n = 7) and obese (n = 8) PCOS women and in 11 regularly cycling age- and weight-matched controls (six lean and five obese). In addition, circulating PRL bioactivity was evaluated by its mitogenic activity on a lymphoma cell bioassay. RESULTS: Oral administration of metoclopramide resulted in a significant increase in serum PRL in all subjects; however, the highest increments, regardless of body mass index (BMI), were observed in control women (p <0.005). Measurements of PRL mitogenic activity on the Nb2 lymphoma cell bioassay revealed a significant increase in the bioactive/immunoreactive (B/I) ratio of PRL under basal and stimulated conditions in obese PCOS subjects (p <0.05). Mean fasting glucose/insulin and glucose/insulin-AUC ratios were significantly lower (p <0.001) in obese PCOS when compared with all other groups. CONCLUSIONS: These data support the existence of low DA hypothalamic tone in PCOS women that is likely involved in the inappropriate LH and PRL secretion frequently seen in this syndrome. In addition, our results suggest changes in PRL bioactivity in obese PCOS that may play a role in the development of hyperinsulinemia; however, whether PRL has a functional significance in the development of the metabolic disturbances frequently seen in PCOS remains to be elucidated.

Adolescent↗
PubMedDate not supplied

Intravenous magnesium sulfate does not increase ventricular CSF ionized magnesium concentration of patients with intracranial hypertension.

Magnesium sulfate has attracted interest as a potential neuroprotectant but passage of magnesium ion into the central nervous system has not been well documented. For this study, we quantified plasma and cerebrospinal fluid (CSF) ionized magnesium concentration after systemic magnesium sulfate infusion in patients with intracranial hypertension. Patients ( N = 9) received an intravenous infusion of 5 g/20 mmol magnesium sulfate (125 mL of a 4% wt/vol solution) over 30 minutes. Before and after dosing, CSF (from an indwelling ventricular catheter) and blood samples were collected at hourly intervals. Ionized magnesium concentration in all samples was determined using an electrolyte analyzer. Baseline plasma and CSF ionized magnesium concentrations were 0.58 +/- 0.05 and 0.82 +/- 0.06 mmol/L, respectively. Intravenous magnesium sulfate infusion significantly increased plasma ionized magnesium concentration (peak, 0.89 +/- 0.11 mmol/L), but CSF magnesium levels did not change during the 4-hour study. Systemic administration of magnesium sulfate failed to increase CSF ionized magnesium concentration in patients with intracranial hypertension despite increasing plasma magnesium levels by >50%.

Adolescent↗
PubMedDate not supplied

Serum ECP levels in asthmatic patients: comparison with other follow-up parameters.

In recent years, eosinophil cationic protein (ECP) has been considered as a useful eosinophilic activation marker in asthmatic patients. In this study, serum ECP levels in different stages of bronchial asthma were evaluated. We studied 123 patients suffering from asthma, which was classified as mild (n = 49), moderate (n = 49), severe asthma (n = 25), and also 31 healthy controls. Serum ECP levels were 13.22 +/- 1.11 ng/mL (mean +/- s.e.m.) in controls, and 30.15 +/- 2.38 ng/mL in asthmatic patients. By subgroups, ECP levels were 24.23 +/- 3.37 ng/mL, 31.69 +/- 4.21 ng/mL and 37.61 +/- 4.52 ng/mL, in mild, moderate and severe asthmatic patients, respectively, being the differences among the three groups statistically significant (P < 0.01-P < 0.001). Peripheral blood eosinophil numbers were 157 +/- 20 eos/mm3 in controls, and 334 +/- 35 eos/mm3, 510 +/- 87 eos/mm3, and 658 +/- 72 eos/mm3, in mild, moderate, and severe asthmatic patients, respectively, with significant differences among all groups (P < 0.05-P < 0.001). The serum ECP levels as well as the eosinophil numbers were higher in symptomatic patients than in the asymptomatic ones (P < 0.01). Moderate negative correlations, although highly significant (P < or = 0.001), were found between serum ECP levels and forced vital capacity (FVC) (rs = -0.27), FEV1, MEF25-75 (rs = -031), and MEF50 (rs = -0.32). There was also a good positive correlation between ECP levels and peripheral blood eosinophil numbers (rs = 0.67, P < 0.001).

Adolescent↗
PubMedDate not supplied

Thyroid peroxidase antibodies in Mexican-born healthy pregnant women, in women with type 2 or gestational diabetes mellitus, and in their offspring.

OBJECTIVE: To search for differences in the frequency of thyroid peroxidase antibodies (TPO-Ab) among 150 pregnant Mexican women who were healthy, had type 2 diabetes mellitus (DM), or had gestational diabetes mellitus (GDM). METHODS: Fifty healthy women, 50 women with type 2 DM, and 50 women with GDM were studied at delivery. In addition, 142 of their offspring were included in the study. TPO-Ab were determined by enzyme immunoassay, and total triiodothyronine, free thyroxine, and thyroid-stimulating hormone (thyrotropin) were measured by radioimmunoanalysis. RESULTS: TPO-Ab were < or = 70 U/mL (negative) in 50% of the healthy women and in 60% and 60% of women with type 2 DM and GDM, respectively (no significant difference). TPO-Ab were 71 to 250 U/mL (slightly positive) in 40% of healthy women and in 30% and 34% of women with type 2 DM and GDM, respectively (no significant difference). TPO-Ab were > or =251 U/mL (strongly positive) in 10% of healthy women and in 10% and 6% of women with type 2 DM and GDM, respectively. One healthy woman had subclinical hypothyroidism, and the rest were euthyroid. The newborn offspring of these Mexican women were euthyroid and had similar frequencies of TPO-Ab (all had TPO-Ab <250 U/mL). CONCLUSION: (1) The frequency of TPO-Ab > or =251 U/mL was similar in pregnant Mexican women with GDM in comparison with those who were healthy or had type 2 DM. (2) The similar high frequencies of slightly positive TPO-Ab in the three groups of pregnant women can partially be explained by the existence of an ethnic factor, the very strong family history of DM in a substantial percentage of them, and the use of a more sensitive and specific assay for detection of TPO-Ab.

Adult↗
PubMedDate not supplied

Eosinophil soluble protein levels, eosinophil peroxidase and eosinophil cationic protein in asthmatic patients.

Eosinophil granular proteins are useful eosinophil activation markers in asthmatic patients. In this study, eosinophil peroxidase (EPO) and eosinophil cationic protein (ECP) levels were assessed in different stages of bronchial asthma in 123 patients suffering from intrinsic (n = 42) and extrinsic (n = 81) asthma, with the aim of evaluating the difference in the protein levels between both types of asthma and their importance as a severity marker of the disease. The geometric mean serum level of EPO was 12.3 +/- 2.17 ng/ml (mean +/- SD) in controls, and 38.6 +/- 3.4 ng/ml in the asthmatic patients. Mean ECP levels were 13.22 +/- 1.11 ng/ml in controls and 30.5 +/- 2.38 ng/ml in patients. Depending on the asthma severity, the EPO levels were 30.4 +/- 4.35, 38.7 +/- 5.29, and 54.46 +/- 9.46 ng/ml in mild, moderate and severe asthmatics, respectively, with the differences being significant between the groups of patients with mild and severe asthma (p < 0.001). ECP levels were 24.23 +/- 3.37 in mild, 31.69 +/- 4.21 in moderate, and 37.61 +/- 4.52 ng/ml in severe asthma. There were significant differences in ECP levels between mild and moderate asthma (p < 0.001) and between mild and severe asthma (p < 0.001). Peripheral eosinophil count was 157 +/- 20 eosinophils/mm3 in controls, 334 +/- 35 eosinophils/mm3 in mild asthmatics, 510 +/- 87 eosinophils/mm3 in moderate asthmatics and 658 +/- 72 eosinophil/mm3 in severe asthmatics, with significant differences between all groups (p < 0.05-p < 0.001). Serum EPO and ECP levels and peripheral eosinophil count were significantly greater in patients with active asthma than in patients with silent asthma (p < 0.001). Significant negative correlations (p < 0.001) were found between serum EPO levels and FEV1 (rs = -0.30), MEF25-75 (rs = -0.33), MEF50 (rs = -0.34). There was also a significant (p < 0.001) and negative correlation between ECP levels and FEV1 (rs = -0.31), MEF25-75 (rs = -0.31), MEF50 (rs = -0.32). A good positive correlation was found between peripheral eosinophil count and EPO levels (rs = 0.80, p < 0.001), and ECP levels (rs = 0.67, p < 0.001). We also found a significant positive correlation between clinical score and peripheral eosinophil count (rs = 0.54, p < 0.001), EPO levels (rs = 0.46, p < 0.001) and ECP levels (rs = 0.52, p < 0.001).

Adolescent↗
PubMedDate not supplied

Hypoglycaemia associated to vaginal insulin placement in rats.

The effect of vaginal placement of insulin was ascertained in rats by measuring plasma glucose levels. A rapid and sustained decrease of plasma glucose levels at 30, 60, 90 and 120 minutes after vaginal insulin administration was observed, returning to basal levels by 240 minutes. Thus, rapid insulin absorption was not curtailed by vaginal mucose. The effect was independent of the rat oestrous cycle phase.

Absorption↗
PubMedDate not supplied

Clinical and hormonal response to short-term intermittent versus continuous oral bromocriptine in hyperprolactinemic women.

UNLABELLED: OBJECTIVE -- To determine if intermittent oral bromocriptine administration could be a useful therapeutic alternative in infertile hyperprolactinemic women. DESIGN -- Open, randomized and prospective study. SETTING -- Outpatient infertility clinic of a third-level medical institution. PATIENTS -- Fourteen low-income women, 23 to 36 years of age with anovulatory infertility (1-13 years in duration) secondary to hyperprolactinemia (>35 ng/mL). Endocrine profile ruled out anovulation of other origin. INTERVENTIONS -- After a control period of 30 days, seven women (group 1) received daily oral bromocriptine (2.5-10.0 mg/day) continuously during two consecutive 30-day periods (T-1 and T-2), and seven women (group 2) received oral bromocriptine only from day 1 to 15 of each 30-day period of treatment. Morning blood samples were drawn similarly during the three periods on days 6 to 8, 13 to 15, and 21 to 23. MAIN OUTCOME MEASURES -- FSH, LH, and prolactin were determined in all samples, estradiol only in samples of days 6 to 8 and 13 to 15, and progesterone exclusively between days 21 and 23. RESULTS: Mean serum prolactin levels during the control period were similarly elevated in groups 1 and 2. A marked decrease occurred during period T-1 (P < .004) and further during period T-2 (P < .05) in both groups, but at no time were significant intergroup differences documented. During the control period all women had a serum progesterone < 3.0 ng/mL (<9.54 nmol/L); during period T-2 it was > or = 3.0 ng/mL in three and five women of groups 1 and 2, respectively. Over the following 10 months of treatment, two and three normal pregnancies and deliveries ensued in groups 1 and 2, respectively. CONCLUSION -- The intermittent use of oral bromocriptine may indeed be a useful therapeutic approach in treating infertile hyperprolactinemic women.

Adult↗
PubMedDate not supplied

Fruit sensitization in patients with allergy to latex.

In the last years, latex has frequently been found to be involved in immediate hypersensitivity reactions. The first case mentioned with recurrent urticaria and laryngoedema was reported by Stern (1) in 1927. Since then, latex has also been implicated in generalized urticaria, rhinoconjunctivitis, asthma and anaphylaxis. Associated sensitization to several fruits is frequently seen in latex-allergic patients with the symptoms described above. This study was performed in seven patients (six females and one male) with hypersensitivity to latex and concomitant fruit sensitization. Six of them were healthcare personnel. The age of the patients ranged from 25-39 years, with a mean of 30 years. Prick tests and intracutaneous tests with latex (10% w/v in PBS), banana, chestnut, avocado, kiwi and melon were carried out. A specific histamine release test (HRT) was performed according to the fluorometric assay. Antigen-specific IgE was also performed. Latex CAP inhibition with banana and SDS-PAGE immunoblotting were carried out in one patient. Although in latex-allergic patients multiple sensitization to fruits may be observed, banana and avocado are those most frequently involved, followed by chestnut and melon. This is likely to be due to the presence of common antigens in these fruits and latex, as demonstrated in our study only for banana and avocado. We consider that further investigation is needed on the possible sensitization to latex in sanitary personnel reporting symptoms after fruit ingestion.

Adult↗
PubMedDate not supplied

Fasting glucose/insulin ratio. An index to differentiate normo from hyperinsulinemic women with polycystic ovary syndrome.

OBJECTIVE: To evaluate a simple laboratory index useful to differentiate normo from hyperinsulinemic women with polycystic ovary syndrome. DESIGN: Open and prospective study. SETTING: Outpatient infertility clinic of a third level medical institution. PATIENTS: Twenty five women 27.8 +/- 3.4 years of age with chronic anovulation, hirsutism and hyperandrogenemia (free testosterone [free-T] > 3.4 pg/mL) but no acanthosis nigricans (group 1) were compared with ten healthy women 27.5 +/- 1.5 years of age (group 2). INTERVENTIONS: Three fasting blood samples were obtained followed by a 100-g, 2-hours oral glucose tolerance test (OGTT). MAIN OUTCOME MEASURES: Glucose, insulin, FSH, LH, E2, free-T, androstenedione (A), DHEAS and 17 alpha-hydroxyprogesterone (17-OHP) were measured in the three fasting samples. Glucose and insulin were also determined in the OGTT samples. The fasting glucose/insulin (G/I) ratio was calculated. RESULTS: In group 2 the fasting insulin was < 16.8 microU/mL, the sum of serum insulin (sigma INS) during the OGTT was < 385 microU/mL (mean + 3SD) and the fasting G/I ratio was > 4.5. The fasting LH, FSH, free-T, cortisol, and insulin were higher in group 1 than in group 2. In group 1, eleven women had a sigma INS below and fourteen above 385 microU/mL. Fasting insulin had a linear correlation with sigma INS (r = 0.780) while the fasting G/I ratio had an exponential correlation with sigma INS (r = -0.699). Fasting insulin versus the G/I ratio best fitted a reciprocal regression model (r = 0.912). For screening of hyperinsulinemia during OGTT, fasting insulin had a 75% sensitivity and 62% specificity while for the G/I ratio it was 79% and 73%, respectively. CONCLUSIONS: Both fasting hyperinsulinemia (> 16.8 microU/mL) and a fasting G/I ratio < or = 4.5 can satisfactorily differentiate women with hyperandrogenism and hyperinsulinemia from those with normoinsulinemia. However, the ratio does not require a previous definition of a normal value as for fasting or post-oral glucose insulin levels, and thus, it can be easily calculated in daily clinical practice to establish specific therapeutic maneuvers at an early stage of the evaluation of such patients.

Adult↗