Biomedical subjects

Marcela González

Publications and source records attributed to Marcela González.

6 recordsLinked to original sources

PubMed2006

Role of endogenous nitric oxide in classic preconditioning in rat hearts.

Ischemic preconditioning (IPC) protects the heart against subsequent sustained ischemia reperfusion (RP). Despite many triggers and signaling pathways, which seem to be involved in IPC, the IPC-mechanisms remain a controversial issue. One of them is endogenous production of nitric oxide (NO). To assess the role of NO in IPC and its relation with glycogen and glycolysis, the effects of inhibiting NO synthase with L-NAME (50 microM) were examined in IPC rat hearts perfused with medium containing 10 mM glucose. Left ventricular developed pressure-rate product (RPP) and end diastolic pressure (EDP), lactate and glycogen contents, and cell viability were measured. Global ischemia (25 min) was followed by 30 min RP. IPC consisted in one cycle of 3 min ischemia-5 min RP. IPC reduced EDP and improved RP recovery of RPP. L-NAME had no effects on the non-IPC group but abolished these effects of IPC. IPC reduced ischemic decrease of glycogen and the acceleration of glycolysis, and improved cell viability. L-NAME did not affect these effects of IPC. The results suggest that NO is ineffective on the noxious effects of ischemia-RP in non-IPC hearts and on the effects of IPC on cell viability, glycogenolysis and glycolysis whereas it is only involved in functional protection.

Animals↗

PubMed2006

Iron depletion affects nitrogenase activity and expression of nifH and nifA genes in Herbaspirillum seropedicae.

Herbaspirillum seropedicae Z67 is a nitrogen-fixing bacterium able to colonize the rhizosphere and the interior of several plants. As iron is a key element for nitrogen fixation, we examined the response of this microorganism to iron deficiency under nitrogen fixing conditions. We identified a H. seropedicae exbD gene that was induced in response to iron limitation and is involved in iron homeostasis. We found that an exbD mutant grown in iron-chelated medium is unable to fix nitrogen. Moreover, we provide evidence that expression of the nifH and nifA genes is iron dependent in a H. seropedicae genetic background.

Bacterial Proteins↗

PubMed2006

[Ultrasonographic estimation of the normal volume of the thyroid gland in pediatric populations].

INTRODUCTION: The World Health Organization bases its reference standards for normal thyroid volume on values derived from measurements of European children. However, WHO recommends that normal values for each region be estimated separately, given the variability as a consequence of geographic, racial, and nutritional differences. OBJECTIVE: A normal standard of thyroid volume was estimated for the pediatric population of Bogotá, Colombia. MATERIALS AND METHODS: A cross-sectional study was carried-out in 591 children assessed at the Clínica Jorge Bejarano, Bogotá, Colombia, between January and August 2003. Children with maternal or personal history of thyroid disease and those with abnormal weight or height characteristics were excluded. Age, weight, and body surface index were recorded for each child. Thyroid volume was estimated by ultrasonography using the ellipse formula. RESULTS: The mean estimated volume for each age group was as follows: 0.6 +/- 0.2 cm3 for neonates, 1.1 +/- 0.6 cubic centimeters for milk-fed babies, 2.2 +/- 1.3 cc for pre-school age children, 3.0 +/- 1.7 cc for school age children and 5.7 +/- 3.1 cc for adolescents. Thyroid volume increases with increasing body surface. A linear relationship between the natural logarithm of the thyroid volume and the square root of the body surface was found. CONCLUSIONS: The normal thyroid volume for Bogotá children was smaller than the World Health Organization reference value. Values described in the current study are recommended for local use as the normal parameter.

Adolescent↗

PubMed2005

Libido and orgasm in middle-aged woman.

OBJECTIVES: Determine which social, demographic and sexual function variables that most influence libido or desire and orgasm domains in the premenopausal and postmenopausal women. METHODS: A cross-sectional analysis of 231 Colombian-born women, aged 40-62 years. The sexual function was measured by self-questionnaire. The analysis was performed by using the chi2-test and multivariate regression analysis. The sexual function was divided in five domains: desire, arousal, lubrication, orgasm, pain; additionally satisfaction was included. RESULTS: The women with a higher level of education and with a good perception of their satisfaction with their partners, reported better performance in the desire. Age and the non existence of sexual partner influenced in a negative way on the desire. In sexual active women the orgasm was negatively influenced by low satisfaction scores, lack of emotional closeness with their partners and low educational level. High scores in lubrication and desire were associated with a good performance in the orgasm. The hormone therapy (HT) was associated with better scores in orgasm. CONCLUSIONS: Age, level of education, the presence or lack of sexual partner, degree of satisfaction with emotional closeness with the partner and adequate lubrication, influence the desire and orgasm domains in a significant way. By identifying these associations we can then perform some inexpensive interventions. Improving lubrication for menopausal women. Including men in educational activities to sensitize them toward women's feelings. Organizing educational campaigns for middle-aged women to demystify that sexuality is only for young people.

Adult↗

PubMed2005

Alterations of the renal function and oxidative stress in renal tissue from rats chronically treated with aluminium during the initial phase of hepatic regeneration.

Various indices of renal functions during the early stage of hepatic injury were studied in rats chronically treated with aluminum (Al) lactate. Tubular and hemodynamic parameters were analyzed four days after producing a 65% partial hepatectomy (PH). Water and sodium balances were also studied. Oxidative stress and the activity of Na-K-ATPase were determined in renal tissue. The rats were distributed in four groups: control, Al, PH, Al+PH. Al did not modify the hemodynamic renal functions and the PH-group reduced the glomerular filtrate rate (GFR). The Al + PH group presented a decrease in the renal blood flow and accentuated the GFR fall as compared with PH. The fractional excretion (FE) of water and sodium increased in the PH group. The rats chronically treated with Al and then submitted to the PH protocol developed a further increase in FE of water but a reduction in FE of sodium. Both PH and Al promoted an increase in the aldosterone. PH and Al induced a similar increase of the lipoperoxidation status with reduction of glutathione (GSH) and the activity of glutathione peroxidase (GSH-Px). The data indicated that Al is an inhibitor of catalase. The GSH and GSH-Px activity in the Al + PH group demonstrated a synergic effect of Al and PH. This work demonstrates that rats treated chronically with Al and submitted to another injury (such as hepatic damage) can aggravate renal functions, probably by increasing the oxidative state, at least in kidneys.

Animals↗

PubMed2004

Sexual function, menopause and hormone replacement therapy (HRT).

OBJECTIVE: To assess the prevalence of female sexual dysfunction in premenopausal and postmenopausal women with and without hormone replacement therapy (HRT). To determine the relationship between menopause and sexual activity, and the impact of HRT on sexual function. METHODS: A cross-sectional analysis of 231 Colombian-born women, aged 40-62 years. Sexual function was measured by self-questionnaire. The analysis was performed by using the chi2-test and multivariate regression analysis. The sexual function was divided in five domains: desire, arousal, lubrication, orgasm and pain; in addition, questioning about sexual satisfaction was included in the research. RESULTS: In the study 38.1% of women showed sexual dysfunction in the desire, and 25% in the arousal, these two being the most affected domains. Even though menopause marginally decreases all stages of sexual function, this association was statistically significant only for the lubrication and pain domains. HRT improves sexual function in the orgasm, lubrication and pain domains in a statistically significant manner. The level of sexual satisfaction was better on postmenopausal women with HRT than ones without HRT. Age negatively influences almost all sexual function domains in a significant manner. CONCLUSIONS: Menopause affects in a negative manner some domains of female sexual function. HRT improves some factors of the sexual function during menopause but it not improves desire and arousal which were the most affected domains. There is a negative association between age and female sexual response in middle-aged women.

Adult↗