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Biomedical subjects

A Parra

Publications and source records attributed to A Parra.

At least 73 records · Page 4Linked to original sources
PubMed1995

Simultaneous determination of cefepime and L-arginine in injections by second-derivative spectrophotometry.

A simple spectrophotometric assay for the determination of cefepime and L-arginine in injections is described. Since zero-order spectra showed considerable overlap, second-derivative spectrophotometry was used to enhance the spectral details. A linear relationship between second-derivative amplitude and concentration of each compound was found. Beer's law was obeyed up to 50 and 22 micrograms ml-1 of cefepime and arginine, respectively, in the second-derivative mode. Detection limits were 0.31 and 0.58 micrograms ml-1 for cefepime and arginine, respectively. The method, which is rapid, simple and does not require any separation step, has been successfully applied to the assay of commercial injections containing cefepime and arginine.

Arginine↗
PubMed1995

Opposite effects of breakfast vs. oral glucose on circulating androgen levels in healthy women.

Since certain hormone abnormalities can be food-dependent as in some cases of nodular adrenal hyperplasia, as a first step to study other more frequent endocrine disorders, using a standard meal as means of a more physiologic stimulus, we investigated in healthy women whether or not the changes in serum glucose, insulin, cortisol, and androgens are different following a breakfast than after oral glucose alone. Ten women (group 1) ingested a 725 kilocalories (173 kiloJoules) breakfast and ten women (group 2) ingested a 100-g glucose load at 8:00 A.M. Serum glucose, insulin, cortisol, dehydroepiandrosterone sulfate (DHEAS), free testosterone (free-T), and androstenedione (A) were determined every 30 min for the next 2 h. Serum glucose rose higher in group 2 than in group 1 (p < or = 0.05), yet insulin increased similarly in both groups. In group 1 free-T and DHEAS increased at 30 min (p < or = 0.05) while cortisol decreased (p < or = 0.04); A did not change. On the contrary, in group 2 only a decrease in free-T (p < or = 0.01) was detected. In these healthy women, serum androgen changed inversely depending on the type and composition of the oral stimulus used. The simultaneous increase of serum insulin, free-T and DHEAS coinciding with a cortisol decrease may enhance insulin anabolic effects following breakfast, but not after oral glucose alone.

Administration, Oral↗
PubMed1995

Serum androgen changes during meal-induced hyperinsulinemia and after acute sequential blockade and hyperstimulation of insulin release in women with polycystic ovary syndrome.

To investigate if acute changes in endogenous insulin release are associated with similar changes in serum androgen, 13 healthy ovulatory women (group 1) and six women with polycystic ovary syndrome (PCOS) and hyperinsulinemia, three with acanthosis nigricans (group 2) were studied. On day 1 all women ingested a 725 kilocalories breakfast between 7:30 and 8:00 A.M. The next day (day 2) only PCOS women had the breakfast and a simultaneous 90-min intravenous infusion of epinephrine (E, 6 micrograms/min) and propranolol (P, 80 micrograms/min). On both days serum glucose, insulin, cortisol, 17 alpha hydroxyprogesterone (17 OHP), dehydroepiandrosterone sulfate (DHEAS), free testosterone (free T), and androstenedione (A) were determined every 30 min for a period of 3 h. In group 1, glucose, insulin, free T, and DHEAS simultaneously rose (p < or = 0.026) while cortisol and 17 OHP fell (p < or = 0.020). Group 2 on day 1 had fasting and meal-stimulated hyperinsulinemia but all serum steroids progressively decreased. In only one woman free T rose. On day 2 during the E + P infusion, glucose increased yet fasting insulin remained constant and serum steroids decreased again. During the 90 min post-infusion, insulin sharply increased but no acute elevation in any steroid occurred. In conclusion, in PCOS women no parallel changes in serum androgen concentrations were seen in association with acute truly physiologic endogenous hyperinsulinemia or during the acute pharmacologically induced hypoinsulinemia and subsequent hyperinsulinemia.

Adult↗
PubMed1994

Activation of protein kinase C family members by the novel polyphosphoinositides PtdIns-3,4-P2 and PtdIns-3,4,5-P3.

The effect of phosphoinositides on the activity of protein kinase C (PKC) isotypes was investigated. PKC alpha, beta I, beta II, gamma, delta, epsilon, eta, and zeta were expressed in baculovirus-infected insect cells and purified by column chromatography. The calcium-activated PKC isotypes alpha, beta I, beta II, and gamma were not significantly activated by any of the phosphoinositides investigated (phosphatidylinositol-4-phosphate (PtdIns-4-P), PtdIns-3-P, PtdIns-4,5-P2, PtdIns-3,4-P2, and PtdIns-3,4,5-P3) when added in the presence of concentrations of phosphatidylserine that give maximal stimulation. The calcium-insensitive PKC isotypes delta, epsilon, and theta also showed little response to PtdIns-3-P, PtdIns-4-P, or PtdIns-4,5-P2 when these lipids were added in the presence of phosphatidylserine. In contrast, PtdIns-3,4-P2 and PtdIns-3,4,5-P3 caused a 5-15-fold stimulation of these enzymes compared with phosphatidylserine alone. 50% maximal stimulation of PKC epsilon by PtdIns-3,4,5-P3 occurred when this lipid was present at about 1% of the carrier PtdIns-4,5-P2 (about 100 nM). These lipids had little effect on baculovirus-expressed PKC zeta, which was constitutively active. A short chain version of PtdIns-3,4,5-P3, dioctanoyl-PtdIns-3,4,5-P3, activated PKC delta, epsilon, and eta in the absence of other lipids, whereas a short chain version of PtdIns-4,5-P2, dihexanoyl-PtdIns-4,5-P2, did not. Since PtdIns-3,4-P2 and PtdIns-3,4,5-P3 are nominally absent in unstimulated cells and appear within seconds to minutes of stimulation by various cell activators, these lipids could act as second messengers to activate PKC delta, epsilon, or eta in vivo.

Animals↗
PubMed1994

First and second derivative spectrophotometric determination of cefoperazone and sulbactam in injections.

A simple, spectrophotometric assay to measure the concentrations of cefoperazone and sulbactam in injectable formulations is described. Since zero-order spectra are subject to interference, derivative spectrophotometry was used to enhance the spectral details. A linear relationship between derivative amplitudes and the concentrations of the compounds was found. Beer's law is obeyed up to 75 and 80 micrograms ml-1 of cefoperazone in the first and second derivative modes, respectively, and up to 75 micrograms ml-1 of sulbactam in the second derivative mode. Detection limits were 0.64 and 0.88 microgram ml-1, respectively for cefoperazone in the first and second derivative modes and 0.30 micrograms ml-1 for sulbactam in the second derivative mode. The method is rapid, simple, does not require a separation step and has successfully been applied to the assay of commercial injections containing cefoperazone and sulbactam.

Anti-Infective Agents, Urinary↗
PubMed1994

Chemical-microbiological synthesis of ent-13-epi-manoyl oxides with biological activities.

The biotransformation of ent-13-epi-3-keto manoyl oxide, which possesses antileishmania activity, with Curvularia lunata produced ent-6 beta-hydroxy, ent-1 alpha-hydroxy, ent-11 beta-hydroxy and delta 1-derivatives, as well as a reduction product a C-3 (S-alcohol) with another hydroxyl group at C-6 (ent-6 beta) or C-11 (ent-11 beta). The ent-6 beta-hydroxy and delta 1-derivatives inhibited growth of the pathogenic protozoa, Leishmania donovani. The biotransformation of ent-12 alpha-acetoxy-3 beta-hydroxy-13-epi-manoyl oxide and ent-3 beta-acetoxy-12 beta-dihydroxy-13-epi-manoyl oxide gave ent-3 eta,12 beta-dihydroxy-13-epi-manoyl oxide and ent-3 beta,6 beta,12 beta-trihydroxy-13-epi-manoyl oxide (trimanoyl). Both products increased the activity of adenylatecyclase.

Animals↗
PubMed1994

Antimicrobial activity of natural and semisynthetic diterpenoids from Sideritis spp.

The antimicrobial activity of 22 natural diterpenoids of endemic Sideritis from Eastern Andalusia (Spain) is described. Only ent-kaur-16-ene foliol and ent-beyer-15-ene isopusillatriol proved to be active towards Gram-positive and acid-fast bacteria. The introduction of a ketonic group at C-15 on ent-kaur-16-enic systems produced a remarkable degree of activity.

Anti-Bacterial Agents↗
PubMed1993

Gender differences in escape-avoidance behavior of mice after haloperidol administration.

Gender differences in the disruptive effects of haloperidol on some reinforced behaviors have been observed in different species. However, the inhibitory action of haloperidol on the acquisition and performance of escape-avoidance behavior has only been investigated in male subjects. The present experiment was designed to investigate possible gender differences in the effects of haloperidol on the initial phase of an escape-avoidance learning task. Male and female mice of the OF1 strain were given a single training session in a shuttle-box. Thirty minutes prior to the behavioral test, mice were injected IP with haloperidol (0.25 mg/kg) or physiological saline (10 ml/kg). Latencies of escape and avoidance responses and the number of nonresponses, escapes, avoidances, pseudoavoidances, crossings during the adaptation period, and crossings during intertrial intervals (ITIs) were evaluated. The disruptive action of haloperidol on the escape-avoidance behavior of the mice was greater in males than in females. The number of nonresponses were higher and the number of escapes lower in treated males than in their female counterparts. These gender differences were not found in control subjects. Activity measures of spontaneous motor behavior (crossings in the adaptation period and during ITIs) did not present gender differences either. Several possible mechanisms responsible for this greater susceptibility of males to the inhibitory effects of haloperidol on escape-avoidance learning are discussed, especially the modulating role of female hormones on dopaminergic activity.

Animals↗
PubMed1993

First- and second-derivative spectrophotometric determination of imipenem and cilastatin in injections.

First- and second-derivative spectrophotometry has been used for the quantitation of mixtures of imipenem and cilastatin sodium, compounds that have closely overlapping spectral bands. Beer's law was obeyed at concentrations up to 100 micrograms ml-1 of imipenem in both the first- and second-derivative modes and up to 75 micrograms ml-1 of cilastatin in the first-derivative mode. Detection limits at the P = 0.05 level of significance were calculated to be 0.40 and 0.52 micrograms ml-1 of imipenem and cilastatin sodium, respectively, in the first-derivative mode, and in a range from 0.45 to 0.68 micrograms ml-1 for imipenem in the second-derivative mode. The method, which is rapid, simple and does not require a separation step, has been successfully applied to the assay of commercial injections.

Cilastatin↗
PubMed1993

Age-related changes in the metoclopramide-induced prolactin release in nulliparous women.

OBJECTIVE: To assess the metoclopramide-stimulated PRL response in nulliparous women as a function of chronological age (CA). DESIGN: Open and prospective study. SETTING: Outpatient endocrine clinic of a third level medical institution. PATIENTS: Fifty-one clinically healthy volunteer nulliparous women 15.8 to 48.2 years of age, with regular menses at least 1 year before the study (except 3 postmenopausal women) and no regular drug ingestion during the last 6 months, studied on days 18 to 22 of their menstrual cycle. INTERVENTIONS: After a 30-minute rest, three basal blood samples were obtained; oral metoclopramide (10 mg) was administered followed by subsequent blood samples at 60, 90, and 120 minutes. MAIN OUTCOME MEASURES: Duplicate serum PRL determinations were performed by RIA in all samples with P and E2 only in the pool of the basal samples. Hypothesis was formulated before data collection. RESULTS: All menstruating women had serum P levels > or = 4.0 ng/mL (> or = 12.72 nmol/L). A linear correlation was observed between CA and the serum PRL response, and also between CA and serum E2. Multiple regression analysis showed that CA and body mass index had the most marked effect on PRL response. Women < or = 25.0 years old had a serum PRL response and mean basal serum E2 levels lower than women > 25.1 years old. CONCLUSIONS: The metoclopramide-induced PRL response in nulliparous women augmented linearly as CA increased, suggesting a gradual decrease in the dopaminergic tone in older women, perhaps partially compensated by a high estrogen level to prevent an unrestrained rise in serum PRL levels.

Administration, Oral↗
PubMed1993

Serum pattern of different molecular forms of prolactin during normal human pregnancy.

In this study, the molecular heterogeneity of prolactin was analysed in serum from normal women throughout pregnancy. Lectin affinity chromatography and denaturing polyacrylamide gel electrophoresis under reducing and non-reducing conditions, followed by Western blotting and immunostaining were used to resolve and identify the molecular variants of prolactin. During the first trimester, large molecular forms (64 and 53 kDa) and those corresponding to glycosylated and non-glycosylated prolactin (25 and 23 kDa, respectively) were present either under reducing or non-reducing conditions. The 64 and 23 kDa were the predominant species at this stage of gestation. As pregnancy progressed, the 64 kDa variant, which did not bind to concanavalin A, decreased until disappeared at the third trimester of gestation. The unbound/bound ratio of serum prolactin to concanavalin A increased only at the third trimester; however, the relative proportions of concanavalin A-bound prolactin did not show statistically significant changes along the gestational period. The results demonstrated the occurrence of changes in the heterogeneity of prolactin during gestation and further confirmed previous observations that various forms of non-glycosylated prolactin are indeed the predominant species in serum from normal women throughout pregnancy.

Adult↗
PubMed1993

Patients with psoriasis often have increased serum levels of IgA antibodies to gliadin.

It was recently observed that in six patients with psoriasis and one with palmoplantar pustulosis, with newly discovered gluten intolerance, a gluten-free diet had a remarkable effect on the skin lesions. This prompted us to undertake a screening investigation to discover whether increased levels of serum antibodies to gliadin are more common in patients with psoriasis than in healthy persons. IgA and IgG antibodies to gliadin (IgA AGA and IgG AGA) were quantified by a micro-ELISA method. Out of 302 patients with psoriasis, 16% (18 females, 31 males) showed serum IgA AGA levels above the 90th percentile value (51 u/ml) of the reference group. This tendency was even more marked when the proportion of patients with values > 70 u/ml was compared with the corresponding proportion of 99 reference subjects. Thus, 3% of the reference subjects but 7.9% of the patients had values > 70 u/ml. The corresponding figures for men were 1.6% and 8.9%, respectively. Men with psoriasis had a significantly higher mean IgA AGA than the male reference group. The means based on logarithmic values of the individual IgA AGA values were significantly higher in the psoriatic groups than in the reference groups. Although the mean level of IgG AGA was not increased in the psoriasis group, there was a correlation between the values for IgA AGA and IgG AGA. The serum concentrations of IgG, IgA and IgM were also measured. In the male patients, the mean IgA value was significantly increased. Women in whom IgA AGA was elevated also showed a significantly increased mean IgA.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

[Cancer of the middle third of the choledochus: an infrequent diagnosis].

We report the case of an 80-year-old woman with a previous history of HBP, hysterectomy due to cancer of the uterus and cholelithiasis, who was admitted in our hospital because of diffuse abdominal pain, marked jaundice, choluria and acholia during one week, together with anorexia and loss of weight. Blood chemistry results disclosed a total bilirubin of 11 mg/dl, a direct bilirubin of 8 mg/dl, GGTP 826 U/I, alkaline phosphatase 287 U/I, AST 285 U/I, ALT 837 U/I and LDH 242 U/I. The CA 19-9 marker was higher than 500 U/ml. The abdominal ultrasound examination did not show any space-occupying lesions; the extra and intrahepatic bile ducts were very dilated and the gall bladder showed multiple stones within its contents. The endoscopic retrograde cholangiopancreatography (ERCP) showed a homogeneous filiform defect at the middle third of the common bile duct of approximately 1 cm in length and with a marked dilatation of the bile ducts. A percutaneous drainage of the bile tree was performed, but the patient died.

Aged↗
PubMed1993

The reproducibility of the 50-g, 1-hour glucose screen for diabetes in pregnancy.

OBJECTIVE: To explore the day-to-day reproducibility of the 50-g, 1-hour glucose screening test performed on 2 consecutive days in the same women. METHODS: Eight women at 12-23.6 weeks' gestation (early subjects) and 80 women at 24-28 weeks (late subjects) without known diabetes mellitus were studied. The glucose screening test was performed in the morning on 2 consecutive days in the same women, under an identical or opposite sequence of fasting and fed conditions. The women were thus divided into four subgroups: fast-fast, fed-fed, fast-fed, and fed-fast. Duplicate serum glucose concentrations were measured by the glucose oxidase method. Paired Student t test was used to analyze day-1 versus day-2 glucose levels in each woman of each subgroup. RESULTS: The serum glucose concentrations were higher on day 1 than on day 2 in the subgroups fast-fast and fast-fed (P < .05) in both early and late patients, whereas the opposite was seen in the subgroups fed-fast (P < .05). No significant differences were observed in the subgroups of fed-fed. At three different glucose thresholds (130, 135, and 140 mg/dL), there was more than 90% daily reproducibility for normal results in both groups, and nearly 50 and 83% daily reproducibility for abnormal results in the early and late patients, respectively. CONCLUSIONS: Up to 28 weeks of pregnancy, the screening test had a high reproducibility for normal results. For abnormal results, daily reproducibility was better after than before 24 weeks' gestation, regardless of prior testing conditions. Depending on the pre-testing conditions, the use of a different serum glucose threshold seems warranted.

Adult↗
PubMed1993

[Serum prolactin during oral metoclopramide in normal nulliparous women].

As a first step in an extensive project planned to determine serum PRL levels in response to oral metoclopramide in women with a diverse gyneco-obstetric history, it was decided to study 51 clinically healthy nulliparous women, aged 15.8 to 48.2 years, with history of regular menses at least one year before the study (except the three postmenopausal women), with no regular drug ingestion during the last six months. Women were studied on days 18 to 22 of menstrual period, after a 30 minute rest on basal conditions (3 samples) at 60, 90, and 120 minutes after a single 10 mg. oral dose of metoclopramide. Duplicate PRL determinations were performed in all samples and progesterone(P) only in a pool of the three basal samples by radioimmunoanalysis. All women had serum P levels > or = 4.0 ng/ml. A significant linear positive correlation (r > or = 0.6795, p < 0.001) was observed between chronologic age (CA) and serum PRL levels, regardless the way they were expressed. Considering the individual responses it was decided to divide the group according to CA and it was observed that serum PRL levels--expressed in any form were always significantly greater in women aged > 25 years (Group 2) in contrast with women aged < or = 25 years (Group 1). Since differences were evident, percentiles 3, 50 and 97 for serum PRL levels were calculated during each test time for both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1992

Esophageal atresia and tracheoesophageal fistula in two infants born to hyperthyroid women receiving methimazole (Tapazol) during pregnancy.

We report on 2 newborn infants with esophageal atresia and tracheoesophageal fistula (EA + TEF) born to hyperthyroid mothers receiving methimazole (Tapazol) before and during their entire pregnancies. Both mothers were euthyroid during gestation and developed hydramnios diagnosed during weeks 34 and 33 of gestation. Premature delivery (36.2 weeks of gestation) occurred in one case, and both newborn infants were small for date with palpable goiter; one of them had other associated malformations. Hypothyroidism was diagnosed by laboratory tests in both cases. Corrective surgery was undertaken, but both newborn infants developed septicemia and renal insufficiency and died in the first week of life. The EA + TEF and a normally placed enlarged thyroid gland were confirmed at necropsy. These cases represent a previously unreported example of the association of maternal ingestion of methimazole during pregnancy and EA + TEF.

Abnormalities, Drug-Induced↗