Search PubMed⌕ Search

Biomedical subjects

C Vega

Publications and source records attributed to C Vega.

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

The role of matching menstrual data with hormonal measurements in evaluating effectiveness of postcoital contraception.

The effectiveness of postcoital contraception can only be estimated. The most commonly used method of calculation compares the expected pregnancy rate in the exposed population to the resultant pregnancies after treatment. Estimation of the fertile period and the day of ovulation are critical to calculate the expected pregnancies. The aim of this study was to improve the accuracy of calculations by evaluating the hormonal status on the day of contraceptive treatment. A total of 483 consecutive women requesting postcoital contraception was included in a prospective observational trial. A blood sample was obtained at the moment of consultation to measure serum luteinizing hormone, estradiol, and progesterone concentrations. An ethinylestradiol-levonorgestrel combination (100 micrograms/500 mg for two doses, 12 h apart) was then prescribed. The fertile period was estimated according to previous hormonal studies in the normal cycling population. Of 483 women, 64 (13.25%) women were excluded because they presented irregular menstrual cycles and 37 (7.6%) women were lost to follow-up. Two pregnancies occurred in the remaining 382 women. Following Wilcox's and Trussell's methods, 21.1 and 17.75 pregnancies should be expected, yielding an overall treatment effectiveness of 90.52% (95% confidence interval [CI] 62.58%-97.6%) and 88.73% (95% CI 55.93%-97.12%), respectively. Hormonal data were available in 356 women; 303 of whom presented with regular cycles. Hormonal information in this group restricted the number of exposed cases to 88 women. Of the women included in Trussell's method of analysis, only 51 (51.5%; p < 0.05) were at risk using hormonal data. Fifty-six percent (95% CI 34.9%-75.6%) of women with luteinizing hormone levels > 20 IU/L were not between days-1 and +1 of the cycle. Hormonal studies suggest that methods based on pregnancy risk calculated by cycle day do not faithfully reflect the real exposure.

Contraceptives, Postcoital, Hormonal↗
PubMed1999

Hepato-biliary abnormalities secondary to ceftriaxone use: a case report.

Ceftriaxone was approved in 1997 for the treatment of otitis media despite previous studies that documented an association of ceftriaxone with elevated hepato-biliary enzymes and transient biliary stasis. The case cited here highlights the need for continued awareness education for physicians who may use ceftriaxone to treat common illnesses such as acute exudative tonsillitis and otitis media in children. Specifically, for children with a family history of gallbladder, biliary tract, liver or pancreas dysfunction, ceftriaxone may not be the drug of choice since the likelihood of complications is increased in this population. Additionally, ceftriaxone may cause problems in either adults or children with preexisting disease, who may not be well-nourished, or who may be dehydrated.

Alanine Transaminase↗
PubMed1997

On the reaction mechanism of class Pi glutathione S-transferase.

Theoretical calculations were performed to examine the ionization of the phenolic group of Tyr7 and the thiol group of glutathione in aqueous solution and in the protein class-pi glutathione S-transferase (GST-Pi). Three model systems were considered for simulations in the protein environments the free enzyme, the complex between glutathione and the enzyme, and the complex between 1-chloro-2.4-dinitrobenzene, glutathione, and the enzyme. The structures derived from Molecular Dynamics simulations were compared with the crystallographic data available for the complex between the inhibitor S-(p-nitrobenzyl)glutathione and GST-Pi, the glutathione-bound form of GST-Pi, and the free enzyme carboxymethylated in Cys47. Free-energy perturbation techniques were used to determine the thermodynamics quantities for ionization of the phenol and thiol groups. The functional implications of Tyr7 in the activation of the glutathione thiol group are discussed in the light of present results, which in agreement with previous studies suggest that Tyr7 in un-ionized form contributes to the catalytic process of glutathione S-transferase, the thiolate anion being stabilized by hydrogen bond with Tyr7 and by interactions with hydrating water molecules.

Animals↗
PubMed1995

Pyrogens specifically disrupt the acquisition of a task involving cognitive processing in the rat.

In addition to changes in body temperature and other metabolic and physiological responses corresponding to immune activation, pyrogens can induce profound behavioral changes referred to collectively as sickness behavior. One feature of sickness behavior, sometimes reported in clinical settings, but rarely exposed to experimental analysis, is depressed cognitive functioning. The present series of five experiments sought to demonstrate the existence of specific cognitive deficits in rats, independently of any confounding performance effects of pyrogen injections. The behavioral task used, called autoshaping, consisted of presenting hungry Wistar rats with a stimulus (introduction of a retractable lever) that predicted food delivery. Control rats quickly learned to press the lever, although this response does not influence the probability of food delivery. When pyrogens (250 micrograms/kg lipopolysaccharide, 4 micrograms/rat interleukin-1 beta, or 300 mg/rat yeast) were injected to rats during acquisition of this task, they severely disrupted acquisition while the pyrogen was active. The same treatments were, however, without effect on performance when injected later, when performance had stabilized. It is argued that these results demonstrate specific, performance-independent effects of pyrogens on the cognitive processes needed for the acquisition of this task. The results are discussed in terms of the relationship between these effects and the cytokines induced in the brain by pyrogens, and in terms of the exact nature of the cognitive process likely to be affected.

Animals↗
PubMed1994

Increased sensitivity to triiodothyronine (T3) of broiler lines with a high susceptibility for ascites.

1. In the studies reported here, broiler lines divergently selected for susceptibility to ascites under low temperature conditions were tested for their sensitivity to 3,3',5-triiodothyronine (T3) with respect to growth rate, rate of mortality, plasma concentrations of T3, right ventricular hypertrophy (RVH) and incidence of ascites. 2. Mean body weight of the ascites-susceptible line (BC-line) was higher than that of the ascites-resistant line (A-line). Adding 0.5 mg T3/kg of the diet depressed growth rate to the same extent in both lines. The effect of T3 on growth was more pronounced for males than for females. 3. T3-supplementation increased the relative weight of the heart and the incidence of RVH to the same extent in both lines. More of the T3-treated BC-line chickens had fluid accumulation in the abdominal cavity than the T3-treated A-line chickens. 4. Dietary T3-treatment depressed the plasma concentration of growth hormone (GH) profoundly and insulin-like growth factor (IGF-I) slightly but to the same extent in both lines. The coefficient of variation of GH concentrations indicate that T3 treatment mainly decreased GH-pulsatility in young growing broilers. 5. Higher doses of dietary T3 (1 and 2 mg/kg) increased mortality in a dose-dependent manner. With 2 mg T3/kg, mortality in the BC-line was almost double that in the A-line. 6. These studies indicate that the development of ascites could be linked with thyroid function. Moreover, dietary T3 supplementation could be used to help identify ascites-inducing factors or genetic lines with differential sensitivity for ascites.

Animals↗
PubMed1994

Bovine babesiosis: a review of recent advances.

Bovine babesiosis, caused by parasites of the genus Babesia, is one of the world's most severe tick-borne problems of cattle in temperate to tropical areas. In the Americas Babesia bovis and B. bigemina are the causative agents, with the former considered to produce the greatest economic impact. The great complexity of the relationships causal agent-vector-host has severely hindered the efforts towards the production of a safe, long-lasting, solid-protection inducing vaccine. Recent important contributions that have encouraged the study of these agents include the development of in vitro cultivation systems, procedures for the isolation of single infected-erythrocytes, density gradient-based centrifugation systems for the isolation and concentration of both infected erythrocytes and merozoites, isozyme detection and differentiation systems that help discriminate between parasite species, and development of DNA-based diagnostics and characterization protocols. Currently, the study of the cellular immune responses against these parasites is taking new endeavors in order to discern the relationship between B cells, T cells, macrophages and their products and parasites leading to the establishment of solid, long-lasting protection. In an attempt to design a rational vaccine, T cell lines and clones are being established, and phagocytosis of infected erythrocytes and their antigens studied to try to pinpoint relevant epitopes.

Animals↗
PubMed1993

Growth of Candida utilis in solid state fermentation.

In this work, the growth of the yeast Candida utilis on different solid substrate (wheat bran) and supports (sugarcane bagasse and Amberlite resin) imbibed with a liquid culture medium was studied. Growth was followed by sugars consumption, carbon dioxide production rate (CDPR) and cell count. The results showed the ability of the yeast to grow on the three solid media with fairly good viability and total dextrose consumption in the case of sugarcane bagasse and Amberlite, and partial consumption of wheat bran sugars. After two or three days of culture, a five hundred fold increase in cell population was observed.

Journal Article↗
PubMed1991

[Emphysematous pyelonephritis: 3 cases].

We report 3 patients who developed emphysematous pyelonephritis. All were diabetic females over 50 years of age with unilateral necrotizing pyelonephritis. Intra and perirenal gas was demonstrated and all patients had infection by E coli. X ray and ultrasound studies allowed the diagnosis. Antibiotic therapy was unsuccessful and all patients had to be operated on.

Aged↗
PubMed1989

Clindamycin with primaquine for Pneumocystis carinii pneumonia.

Combined therapy with clindamycin and primaquine was used in twenty-eight episodes of Pneumocystis carinii pneumonia in 25 patients, of whom 17 had been unresponsive or intolerant to conventional treatment and 8 were being treated for the first time. The treatment was effective in all but two episodes, the main adverse reaction being a generalised maculopapular rash.

Administration, Oral↗
PubMed1989

Once-daily therapy with ceftriaxone compared with daily multiple-dose therapy with cefotaxime for serious bacterial infections: a randomized, double-blind study.

A randomized, double-blind study was done to compare the efficacy and toxicity of daily single-dose therapy with intravenous ceftriaxone (2 g every 24 h) with daily multiple-dose therapy with cefotaxime (2 g every 6 h) for treatment of serious bacterial infections in nonneutropenic patients. Of the 325 patients who were evaluable for toxicity, 241 (74.2%) were evaluable for efficacy. Infection sites included lung (106), urinary tract (42), skin and soft tissue (43), bone and joint (23), bacteremia (21), and hepatobiliary (5). Definite infections were present in 173 cases (71.8%) and possible infections in 68 (28.2%). Analysis of clinical and bacteriologic responses and adverse drug reactions showed no significant differences between the regimens. Values for 95% confidence limits on the differences between regimens for positive clinical and bacteriological outcomes in definite infections were -0.8% to 3.0% and -1.9% to 9.1%, respectively. Thus, daily single-dose therapy with ceftriaxone was comparable to daily multiple-dose therapy with cefotaxime in treating these bacterial infections.

Adult↗
PubMed1989

[Enalapril in essential arterial hypertension].

The hypotensive effect of enalapril, a converting enzyme inhibitor, given as a single agent once daily, was evaluated prospectively over a 16 week period in 20 subjects. One patient abandoned therapy and 2 were withdrawn (increased creatinine levels in one and the need for associated therapy in the other). Side effects developed in 3 patients: creatinine elevation, skin rush and a "salty taste", respectively. A significant decrease in blood pressure (p less than 0.01) attaining normal levels in 6 out of 17 patients was observed. Normal blood pressure levels were not reached in severe hypertension; the association of hydrochlorothyazide was effective in 5 of 11 such subjects. Thus, enalapril may be safely used as a first stage single therapy in mild or moderate hypertension.

Adult↗
PubMed1987

Anorexia elicited by different catecholamines in rats.

Adrenaline (A) produces a strong anorexic effect, possibly by acting on hepatic receptors (nerve endings on hepatocytes). To study whether this is mediated by alpha- or beta-adrenergic mechanisms, or both, the anorexigenic effects of intraperitoneal injections of A, noradrenaline (NA) and isoproterenol (I) were studied under four different experimental conditions: (I) at the beginning of the dark period in rats fed ad libitum, or (II) on a 24 h-feeding/24 h-fasting schedule; (III) during the light period, under the same feeding schedule; (IV) after an acute 24 h fast. In condition I, the three catecholamines produced a marked decrease in feeding, slightly larger for A. In condition II (dark), they elicited a decrease in food intake about double that in condition III (light), their relative potencies also differed: A greater than I greater than NA in II and A greater than I = NA in III. In IV, the same relative potencies were obtained as in III. A mixture of half-doses of NA and I had the same effect in III and IV as either NA or I alone, suggesting that the alpha and beta effects are additive. However, even a mixture of the full doses of NA and I was not as effective as A in condition IV. This suggests that A is more potent than NA or I at stimulating hepatic adrenergic receptors that cannot be classified as either alpha or beta.

Animals↗