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A Parra

Publications and source records attributed to A Parra.

At least 37 records · Page 2Linked to original sources
PubMed1999

Sex differences in the effects of neuroleptics on escape-avoidance behavior in mice: a review.

The literature of the effects of dopamine antagonists on escape-avoidance, focusing on data obtained in our laboratory with male and female mice, is reviewed. The acute administration of haloperidol, raclopride, clozapine, and SCH 23390 impaired escape-avoidance behavior more in males than in females, and the subchronic administration of haloperidol had a similar effect. This appeared to be a reliable phenomenon, because it was observed in both kinds of administration, in two mouse strains, and with several drugs and doses. The observed results were dose dependent, although the dose-effect relationship was not the same in all drugs. The sex differences in escape avoidance did not seem related to sex differences in the well-known deteriorating effects of these drugs on motor activity. In addition, an analysis of all our studies showed that there were no sex differences in the variability of responses, reinforcing the idea that female subjects should be included in these types of studies.

Animals↗
PubMed1999

Impaired metoclopramide-induced pituitary prolactin release in men with human immunodeficiency virus infection.

To investigate whether metoclopramide-induced prolactin release is impaired in HIV-infected men, we studied 10 clinically healthy HIV-negative adult men (group 1) and 10 consecutive HIV-positive adult men (group 2) with anti-HIV antibodies confirmed by Western blot analysis and a CD4 cell count from 13 to 570x10(6)/L. After a 10- to 12-hour overnight fast, three basal blood samples were obtained at 15-minute intervals (-30, -15, and 0 minutes) and thereafter at 15, 30, 60, 90, 120, 180, and 240 minutes after a 10-mg intravenous bolus of metoclopramide. Duplicate serum prolactin concentrations were measured in each sample with commercially available radioimmunoassay kits. No significant differences between groups were observed in basal prolactin levels. Group 2 had lower serum prolactin concentrations than group 1 throughout the test (P< or =.002). The area under the prolactin curve (mean +/- SD) was also lower in group 2 than in group 1 (7156+/-1433 ng/mL/240 min vs. 12430+/-2454 ng/mL/240 min, P<.0001), and the area under the prolactin curve had a significant correlation with the CD4 cell counts (r = 0.7912, P<.001). These findings suggest that the hypothalamic dopaminergic tone, although present, was clearly diminished in these HIV-positive men regardless of their clinical stage.

Adult↗
PubMed1999

The uncoupled couple? Prolactin and CD4 lymphocytes in HIV infection.

The possible role of prolactin (PRL) in human immunodeficiency virus (HIV) infection is unknown, despite the modulatory role of this hormone in humoral and cell-mediated immune responses. Recent studies have evidenced: (a) intralymphocyte synthesis of dopamine (DA) which down-regulates their own proliferation and differentiation; (b) decreased DA but increased PRL concentrations in cerebrospinal fluid of HIV-infected men; and (c) diminished hypothalamic DA tone in HIV-infected men. The present hypothesis proposes that, in HIV-infected men, a diminished generalized DA tone exists to stimulate human lymphocyte proliferation and differentiation at a maximum possible rate by: (1) decreasing the inhibitory influence of intralymphocyte DA; and (2) maintaining pituitary and extrapituitary (i.e. lymphocyte) PRL synthesis and release as high as possible. If this hypothesis is correct, it may have a potentially important therapeutic implication: the possibility to rebuild the battered immune system in HIV-infected patients from inside the body in a physiologic manner by the parenteral administration of recombinant human PRL.

CD4-Positive T-Lymphocytes↗
PubMed1999

Antimicrobial treatment of an experimental otitis media caused by a beta-lactamase positive isolate of Haemophilus influenzae.

A gerbil model of otitis media induced by a beta-lactamase producing and non-serotypeable isolate of Haemophilus influenzae was used to assess the in-vivo efficacy of co-amoxiclav and cefuroxime at low (5 mg/kg) and high (20 mg/kg) doses. The MIC of the antibiotics tested against the pathogen was 1 mg/L (1/0.5 mg/L for co-amoxiclav). The organism was inoculated (+/-10(6) cfu) by transbullar challenge directly in the middle ear and antibiotic treatment was commenced 2 h post-inoculation and continued at 8 h intervals for three doses. Only high dose co-amoxiclav significantly reduced the number of culture-positive specimens as compared with untreated animals or with other treatment groups (91.7% as compared with 36.7% for high dose cefuroxime). The results obtained in any treatment group were related to middle ear antibiotic level/MIC. Antibiotic concentrations in the middle ear 90 min after administration were about 10% of serum levels at 15 min, probably related to a slight inflammatory response. Only after high dose co-amoxiclav did the concentration in the middle ear exceed the MIC by a factor of four. In otitis media with effusion, if indicated, antibiotics active in vitro should be administered in high doses and, to avoid side effects, probably in short courses.

Amoxicillin-Potassium Clavulanate Combination↗
PubMed1999

The after breakfast 50-g, 1-hour glucose challenge test in urban Mexican pregnant women: its sensitivity and specificity evaluated by three diagnostic criteria for gestational diabetes mellitus.

BACKGROUND: To study the sensitivity and specificity of the 50-g, 1-hour gestational glucose challenge test performed 1 to 2 hours after a non-standardized home breakfast in urban Mexican women by using three different gestational diabetes mellitus diagnostic criteria. METHODS: Four hundred and forty-five consecutive women of 24-28 weeks gestation were studied. The glucose challenge test was performed in the fed state and a week later a fasting 100-g, 3-hours oral glucose tolerance test was carried out in all of them. Duplicate serum glucose concentrations were determined by a glucose-oxidase method. Sensitivity and specificity were calculated using three different diagnostic criteria for gestational diabetes mellitus. RESULTS: The glucose challenge test performed as indicated, with a cutoff of 7.8 mmol/L, had 88-89% sensitivity and 85-87% specificity when using as diagnostic criteria those proposed by the National Diabetes Data Group and by Carpenter & Coustan; by using Sacks et al. criteria, the values were 82% and 88%, respectively. Considering only pregnant women > or = 25 years of age, the sensitivity increased to 92% with the National Diabetes Data Group criteria. Pregnant women < 25 years of age had significantly lower blood glucose values than those with age > or = 25 years during the glucose tolerance test. CONCLUSIONS: For the general group the sensitivity of the glucose challenge test performed 1 to 2 hours after breakfast was similar, based on the National Diabetes Data Group and the Carpenter & Coustan's diagnostic criteria for gestational diabetes mellitus. However, when pregnant women > or = 25 years of age were considered, the use of the former criteria yielded a slightly better sensitivity.

Adult↗
PubMed1998

HLA associations with multiple sclerosis in the Canary Islands.

The study of small island populations has proved informative with respect to the epidemiology and genetics of many complex traits including multiple sclerosis. The class II major histocompatibility antigen DR15 is associated with multiple sclerosis in all groups except Sardinians, where the primary association is with DR4. We compared HLA-DR and -DQ allele frequencies in a representative sample of patients with multiple sclerosis from the Canary Islands with appropriate controls. There was a significant association with DR15 (patients 21/53: 40%: controls 11/55; 20%: chi2=4.09; pc=0.04; relative risk [RR]=1.98). DRB1*1501-DRB5*0101 was present in 17/53 (32%) patients in whom sub-types could be identified compared with 6/55 (11%) controls (chi2=7.21; pc=< 0.01; RR=2.94). All DR15 positive controls carried the DQA1*0102, DQB1*0602 haplotype whereas this was only present in 26/30 patients, suggesting that the primary association is with HLA-DR and not -DQ. We also found a significant increase in HLA-DR4 (16/53 [30%] in patients compared with 7/55 [13%] in controls; pc=0.05). This study contributes a new point on the immunogenetic map of multiple sclerosis in Europe, confirming the primary DR15 association with multiple sclerosis in a previously unstudied population but again highlighting the importance of DR4 in Mediterranean peoples.

Alleles↗
PubMed1998

The higher the dose, the greater the sex differences in escape-avoidance response in mice after acute administration of haloperidol.

Sex differences in the effects of haloperidol in the escape-avoidance response have previously been found in various studies carried out in our laboratory in which mice were used as experimental subjects. Males were more affected than females by the disruptive effects of this neuroleptic of frequent clinical use. In the present work these sex differences were evaluated in a unique training session using several doses of the drug (0.075, 0.25, and 0.75 mg/kg i.p.). The number of avoidances, escapes, nonresponses, crossings during the adaptation period, crossings during intertrial intervals, and response latencies were analyzed. Statistically significant sex differences were found in the number of escapes and nonresponses: males showed fewer escape responses and more nonresponses than females. These sex differences were dose dependent: a positive correlation was obtained between doses of haloperidol and sex differences observed in the number of escapes and nonresponses. The higher the dose, the greater the sex differences. These are related not only to the impairment of motor activity, because no sex differences were found in the number of crossings during the adaptation period and intertrial intervals.

Animals↗
PubMed1998

Sex differences in escape-avoidance response in mice after acute administration of raclopride, clozapine, and SCH 23390.

Sex differences in the effects of haloperidol in the escape-avoidance response in mice have previously been found in various studies carried out in our laboratory. Males were more affected than females by the disruptive effects of this neuroleptic. The work described herein extended the study of these sex differences to raclopride, clozapine, and SCH 23390, using several doses of each drug in acute administration. The results showed dose-dependent sex differences in the deteriorating effects of these dopamine antagonists in the escape-avoidance response. Male mice were more affected by the inhibitory effects of these drugs, showing fewer escape responses and more nonresponses than females. Sex differences were found with all three of the dopamine antagonists studied, indicating, therefore, that these differences do not depend on a unique type of dopaminergic receptor. The results obtained in motor activity, measured by the number of crossings during the adaptation period and the intertrial intervals, suggest that the motor effects are not the origin of these differences. It is concluded that, besides haloperidol, other dopamine antagonists also show sex differences in their behavioral effects in escape-avoidance response in mice, with males being more affected than females by the inhibitory action of these drugs.

Animals↗
PubMed1998

In vivo efficacies of amoxicillin and cefuroxime against penicillin-resistant Streptococcus pneumoniae in a gerbil model of acute otitis media.

The comparative efficacies of amoxicillin and cefuroxime against acute otitis media caused by a penicillin-resistant (MIC, 2 micrograms/ml) Streptococcus pneumoniae strain were assessed in a gerbil model by challenging each ear with 10(7) bacteria through transbullar instillation. Each antibiotic was tested at two doses (5 and 20 mg/kg of body weight) administered at 2, 10, and 18 h postinoculation. Samples were obtained from the middle ear (ME) on days 3 and 7 postinoculation for determination of bacterial counts. Only amoxicillin, at both doses, was able to significantly halt the weight loss in animals, reducing both the number of culture-positive animals and the bacterial concentration in ME samples versus the values for untreated animals. Comparison of the efficacies between the antibiotics, determined by their ability to achieve culture-negative ME specimens, showed that amoxicillin at 5 mg/kg was significantly more active than cefuroxime at the same dose. The use of higher doses of either amoxicillin or cefuroxime did not produce significantly better results than those obtained with the lower dose but caused a greater inflammatory response. The more favorable results obtained with amoxicillin compared with those obtained with cefuroxime could be related to the antimicrobial susceptibility of the pneumococcal strain (MICs and minimum bactericidal concentrations of 1 and 1 microgram/ml and 4 and 4 micrograms/ml for amoxicillin and cefuroxime, respectively) as well as to the better pharmacokinetic parameters obtained with amoxicillin.

Acute Disease↗
PubMed1997

Acute dopaminergic blockade augments the naloxone-induced LH rise in estrogen-treated postmenopausal women.

OBJECTIVES: To assess the effect of estrogen replacement on the simultaneous blockade of the dopaminergic (DA) and opioidergic neural control of hypothalamic-gonadotropic function in postmenopausal women. METHODS: Twenty healthy postmenopausal women, 48-55 years old were randomly assigned to receive either a 4-h naloxone infusion at 2 mg/h (group 1, n = 7) or a 10 mg i.v. bolus of metoclopramide (group 2, n = 7) or both drugs, simultaneously (group 3, n = 6) before and after 3 weeks of transdermal estradiol (100 microg/day). Blood samples were obtained at 30-min intervals during 4 h and duplicate determinations of serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2) and prolactin (PRL) were performed in all samples. RESULTS: In group 1 only a mild but significant LH rise after but not before estrogen replacement was seen. In group 2 PRL had a greater rise after than before estrogen therapy, without other hormonal changes. In group 3 a greater rise in PRL occurred after than before estrogen administration and serum LH had a sustained rise throughout the test only after estrogen replacement (greater than in group 1). No FSH changes were observed. The after-estradiol PRL response was nearly similar in groups 2 and 3. CONCLUSIONS: Our results indicate that in the untreated postmenopausal women, the dopaminergic system has little and the opioidergic system has no significant input in the control of gonadotropin or prolactin release. However, following estrogen replacement, opioids are involved in the inhibition of LH release and stimulating PRL release, while the dopaminergic system acts to inhibit PRL release and modulates LH release or inhibition, depending on the levels of circulating estrogens.

Dopamine↗
PubMed1997

Differences in the metoclopramide-induced prolactin release related to age at first full-term pregnancy or nulliparity.

To investigate if an association exists in parous women between metoclopramide-induced prolactin (PRL) release and chronological age at first full-term pregnancy and to compare their response to a group of non-parous women, we studied 139 healthy, non-lactating women, aged 15.8-48.2 years, on days 18-22 of their menstrual cycle (except two post-menopausal women). There were 61 parous women divided according to chronological age at first full-term pregnancy: 22 were aged < or = 20.0 years, 25 were aged 20.1-29.9 years and 14 were aged > 30 years. There were also 50 nulliparous women and 28 women who had experienced only first trimester abortions. Three basal blood samples were obtained before oral metoclopramide (10 mg) was administered; subsequently samples were taken at 60, 90 and 120 min. Duplicate serum PRL determinations were performed by radioimmunoanalysis and the area under the curve (AUC) calculated. In parous women, the PRL AUC was positively correlated with chronological age at first full-term pregnancy (P < 0.0001), and it was lower than in nulliparous women or in women with abortions. These data suggest that in parous women a greater dopaminergic tone may exist compared with non-parous women, which seems to decrease gradually as chronological age at first full-term pregnancy increases.

Age Factors↗
PubMed1997

Serum eosinophil peroxidase (EPO) levels in asthmatic patients.

Eosinophil granular proteins are a useful eosinophilic activation marker in asthmatic patients. In this study, the eosinophil peroxidase (EPO) levels were assessed in different stages of bronchial asthma, in 123 patients suffering from asthma, classified as mild (n =49), moderate (n = 49), and severe (n = 25), according to the International Consensus Report of Diagnosis and Treatment of Asthma, as well as in 27 healthy controls, with the aim of evaluating the importance of this protein as a severity marker in bronchial asthma, and its possible correlation with parameters such as anamnesis, respiratory function tests, and peripheral blood eosinophil count, and also with some allergologic diagnostic tests, both in vivo and in vitro. The geometric mean serum level of EPO was 9.3 +/- 11.3 ng/ml (median +/- SD) in controls, 28 +/- 37.8 ng/ml in the asthmatic patients. Depending on the asthma severity, the EPO levels were 25 +/- 30.5; 29 +/- 37.1, and 41 +/- 47.3 ng/ml in mild, moderate, and severe asthmatics, respectively, being the significant differences between the group of patients with mild and severe asthma (P < 0.001). The number of eosinophils (eos) in peripheral blood was 157 +/- 20 eos/mm3 in the controls, 334/35 eos/mm3 in mild asthmatics, 510 +/- 87 eos/mm3 in moderate asthmatics, and 658 +/- 72 eos/mm3 in severe asthmatics, with significant differences between all groups (from P < 0.05 to P < 0.001). Both the serum levels of EPO and the number of eosinophils were greater in patients with active asthma patients with inactive asthma (P < 0.001). Significant negative correlations (P < 0.001) were found between serum levels of EPO and FEV1 (rs = 0.30), MEF25-75 (rs = -0.33) and MEF50 (rs = -0.34), and a good positive correlation (rs = 0.80, P < 0.001) was found between EPO levels and the number of eosinophils in peripheral blood. We also found a significant positive correlation between eosinophil number and clinical score (rs = 0.54, P < 0.001) and between EPO levels and the mentioned score (rs = 0.46, P < 0.001).

Adolescent↗
PubMed1997

[Participation of growth factors in human reproduction].

The Growth Factors (GFs) include a group peptidic molecules, with important trophic, mitotic and cellular differentiation effects in most human tissues. This review encompasses the different types of GFs and their biologic effects on tissues involved in the human reproductive process. The importance of the GF in the embryonic development and the implantation process is also commented. Finally, we assess the participation of the GFs in the pathophysiology of the Polycystic Ovary Syndrome and Endometriosis based on recent investigations. The review permit us appreciate the importance of the GFs as mediators of different hormones (in their secretion and biological effects) and in the regulation of some cellular events. The real value of these GFs in the daily clinical practice is as yet to be established, due to the technical laboratory limitations with respect to their identification and quantification, as well as the lack of more clinical research in humans. The GFs are promising molecules for the treatment of infertiles couples and for the application of the technics of assisted reproduction, in vivo and in vitro.

Endometrium↗
PubMed1996

Granulocyte-macrophage colony-stimulating factor as adjuvant therapy for factor as adjuvant therapy for interferon alpha treatment of chronic hepatitis C.

The safety and efficacy of granulocyte-macrophage colony-stimulating factor (GM-CSF) as adjuvant therapy for interferon alpha (IFN-alpha) treatment has been evaluated in 20 non-cirrhotic patients with chronic hepatitis C virus (HCV) infection. Adjuvant therapy with GM-CSF plus IFN-alpha was associated with less myelosuppression than with IFN-alpha alone (P < .01), although the rate of local adverse reactions increased. GM-CSF adjuvant therapy led to a 50% biochemical response (transaminase values within the normal range at therapy end) and to reductions in HCV RNA concentrations (median HCV RNA reduction of 99%, range 8-100%), which were similarly observed in single IFN-alpha recipients (median HCV RNA reduction of 91%, range 38-100%). However, HCV RNA became undetectable in three biochemical responders to the GM-CSF adjuvant therapy, but in only one biochemical non-responder to IFN-alpha alone. The use of GM-CSF as adjuvant therapy is safe and, although it has not improved the biochemical response, it might potentiate the virologic response to IFN-alpha treatment alone.

Adult↗
PubMed1996

Apparent vs real effects of scopolamine on the learning of an active avoidance task.

The effects of scopolamine hydrobromide (0.5 and 2 mg/ kg) administered intraperitoneally to Balb/c male mice before or after training in active avoidance were explored in four training sessions and in a subsequent test session, free of drug. Animals given scopolamine prior to training performed better than controls, an effect that was reversed in the session free of drug. However, a deeper analysis of the data permits us to interpret this increment in the number of avoidance responses as a consequence of the increase in activity produced by the drug and not as learning. In the animals injected with scopolamine after sessions no effects were observed. In conclusion, the results of the present experiment confirm that scopolamine produces an impairment in the acquisition of an active avoidance task, but also show that this impairment can be easily masked by the facilitating effects of the drug on activity.

Animals↗
PubMed1996

Correlation of in-vitro activity and pharmacokinetic parameters with in-vivo effect of amoxycillin, co-amoxiclav and cefotaxime in a murine model of pneumococcal pneumonia.

In an attempt to determine the susceptibility breakpoints for amoxycillin, co-amoxiclav and cefotaxime in pneumococcal pneumonia, a neutropenic mouse model was established and tested with two strains having different susceptibility to penicillins and cefotaxime. With a penicillin-sensitive strain (MIC/MBC = 0.01/0.01 mg/L) the minimum dosage tested achieving significant cure was 2 mg/kg for amoxycillin, co-amoxiclav and cefotaxime. For the penicillin-insensitive strain (MIC/MBC = 1/2 mg/L), the minimum dosage tested giving significant cure was 50 mg/kg for amoxycillin and co-amoxiclav but 100 mg/kg for cefotaxime. Our results support the belief that MICs of amoxycillin, co-amoxiclav and cefotaxime for pneumococcal strains of < or = 0.5 or < or = 1 mg/L can be considered as clinically relevant susceptibility breakpoints.

Amoxicillin↗