Medical Students' Attitude Toward Organ Donation: Understanding Reasons for Refusal in Order to Increase Transplantation Rates.

Objectives: To assess, among medical students, the willingness to donate their own organs or those of a family member, and to establish reasons for refusal.

Materials And Methods: During the 2016 academic year, an anonymous survey was conducted among University of Buenos Aires School of Medicine second-year students.

Results: Of the total 1012 respondents, 81.

Cardiometabolic Changes in Different Gonadal Female States Caused by Mild Hyperuricemia and Exposure to a High-Fructose Diet.

Background: The objective of this study is to observe if mild hyperuricemia and a high-fructose diet influence the cardiovascular and metabolic systems in hypogonadic female Wistar rats compared to normogonadic female rats.

Methods: Fifty-six (56) adult female Wistar rats were used in the present work. Animals were divided into two groups: normogonadic (NGN) and hypogonadic (HGN).

Influence of Normo- and Hypogonadal Condition, Hyperuricemia, and High-Fructose Diet on Renal Changes in Male Rats.

. There is a gender disparity in the incidence, prevalence, and progression of renal disease. The object of this paper is to evaluate the presence and type of renal lesion in normogonadic and hypogonadic male rats in a mild hyperuricemia induced condition and exposed to a high-fructose diet.

Worsening of memory deficit induced by energy-dense diet in a rat model of early-Alzheimer's disease is associated to neurotoxic Aβ species and independent of neuroinflammation.

Diet is a modifiable risk factor for Alzheimer's disease (AD), but the mechanisms linking alterations in peripheral metabolism and cognition remain unclear. Since it is especially difficult to study long-term effects of high-energy diet in individuals at risk for AD, we addressed this question by using the McGill-R-Thy1-APP transgenic rat model (Tg(+/-)) that mimics presymptomatic AD. Wild-type and Tg(+/-) rats were exposed during 6months to a standard diet or a Western diet (WD), high in saturated fat and sugar.

Effect of a high-fat diet on 24-hour pattern of circulating adipocytokines in rats.

We have shown a significant disruption of 24-h pattern of plasma pituitary, adrenal, and gonadal hormones in high-fat-fed rats. Our objective was to assess the effect of a high-fat diet (35% fat) on mean levels and 24-h pattern of several adipocytokines in rats. A normal diet-fed rats (4% fat) were used as controls.

Effect of a high-fat diet on 24-h pattern of circulating levels of prolactin, luteinizing hormone, testosterone, corticosterone, thyroid-stimulating hormone and glucose, and pineal melatonin content, in rats.

Circadian rhythmicity is affected in obese subjects. This article analyzes the effect of a high-fat diet (35% fat) on 24-h changes circulating prolactin, luteinizing hormone (LH), testosterone, corticosterone, thyroid-stimulating hormone (TSH) and glucose, and pineal melatonin content, in rats. When body weight of rats reached the values of morbid obesity, the animals were sacrificed at six different time intervals throughout a 24-h cycle, together with age-matched controls fed a normal diet (4% fat).

Antioxidants restore aortic ring relaxation in pancreatectomized rats.

Vascular response was assessed in rats made diabetic by subtotal pancreatectomy (PPx). Adult male Wistar rats submitted to PPx eight weeks earlier, and exhibiting altered levels of fasting glucose and an abnormal tolerance glucose test, were used. Sham-operated laparotomized rats were employed as controls.

Effect of ethanol on 24-h hormonal changes in prolactin release mechanisms in growing male rats.

This study analyzes the effect of chronic ethanol feeding on 24-h variation of hypothalamic-pituitary mechanisms involved in prolactin regulation in growing male Wistar rats. Animals were maintained under a 12:12 h light/dark photoperiod (lights off at 2000 h), and they received a liquid diet for 4 wk, starting on d 35 of life. The ethanol-fed group received a similar diet to controls except that maltose was isocalorically replaced by ethanol.

Comparative effects of melatonin and vitamin E in restoring aortic relaxation in pancreatectomized rats.

In a previous study we reported the efficacy of melatonin to restore the decreased relaxation response to acetylcholine (ACh) or to sodium nitroprusside (SNP) in aortic rings of rats turned hyperglycemic by subtotal pancreatectomy. The effect was amplified by pre-incubation in a high (44 mmol/l) glucose solution, a situation that resulted in oxidative stress. We hereby compare the effect of another antioxidant, vitamin E, with that of melatonin on ACh response in intact aortic rings or on SNP response in endothelium-denuded aortic rings obtained from pancreatectomized or sham-operated rats.

Effect of melatonin on vascular responses in aortic rings of aging rats.

In old animals a marked reduction in endothelium-dependent relaxation occurs. Since there is evidence that the endothelial dysfunction associated with aging may be partly related to the local formation of reactive oxygen species, the purpose of this study was to examine the effect of the natural antioxidant melatonin (10(-5)mol/l) on in vitro contractility of aged aortic rings under conditions of increased oxidative stress (40 m mol/l glucose concentration in medium). Experiments were carried out in 18-20 months old, Wistar male rats, using adult (6-7 months old) animals as controls.

Effect of melatonin treatment on oxygen consumption by rat liver mitochondria.

The objective of this study was to examine the in vivo effect of melatonin on rat mitochondrial liver respiration. Two experiments were performed: For experiment 1, adult male rats received melatonin in the drinking water (16 or 50 microg/ml) or vehicle during 45 days. For experiment 2, rats received melatonin in the drinking water (50 microg/ml) for 45 days, or the same amount for 30 days followed by a 15 day-withdrawal period.

Melatonin restores endothelium-dependent relaxation in aortic rings of pancreatectomized rats.

In rats turned hyperglycemic by a subtotal pancreatectomy, a decreased relaxation response of aortic rings to acetylcholine (ACh) was found; this effect was amplified by preincubation in a high glucose medium (44 mmol/L). The relaxation response to ACh did not occur in endothelium-denuded rings or after the aortic rings were exposed to l-nitro-arginine methyl ester [L-NAME, a nitric oxide (NO) synthase inhibitor]. Incubation with the NO donor sodium nitroprusside (SNP) restored the impaired relaxation response seen in endothelium-denuded or L-NAME-treated aortic rings.

Effect of ethanol on 24-hour hormonal changes in peripubertal male rats.

We analyzed the effect of chronic (4 weeks) ethanol feeding on 24-h variation of pituitary-testicular function in peripubertal male Wistar rats by measuring circulating concentrations of prolactin, follicle-stimulating hormone, luteinizing hormone, testosterone, and thyrotropin. Animals were maintained under a 12-h light: 12-h dark photoperiod and received a liquid diet for 4 weeks, starting on day 35 of life. The ethanol-fed group received a diet similar to that provided to control animals, except that maltose was replaced isocalorically with ethanol.

24-hour pattern of circulating prolactin and growth hormone levels and submaxillary lymph node immune responses in growing male rats subjected to social isolation.

To assess the effect of social isolation of growing rats on 24-h rhythmicity of circulating prolactin and growth hormone (GH) levels and submaxillary lymph node immune responses, male Wistar rats were either individually caged or kept in groups (4-5 animals per cage) for 30 d starting on d 35 of life. Plasma prolactin and GH levels, and submaxillary lymph node lymphocyte subset populations, interferon (IFN)-gamma release and mitogenic responses to concanavalin A (Con A) and lipopolysaccharide (LPS) were determined at six time intervals during the 24 h span. Social isolation brought about changes in mean values and 24-h pattern of plasma prolactin and GH levels and lymph node immune responses.

Effect of melatonin on vascular reactivity in pancreatectomized rats.

The present study was undertaken to assess whether the improvement of contractile performance of aortic rings by melatonin described in streptozotocin diabetic rats also occurs in another model of type I diabetes, the pancreatectomized rats. Adult male Wistar rats submitted to a subtotal pancreatectomy and exhibiting altered levels of fasting glucose and an abnormal tolerance glucose test, were used. Sham-operated laparotomized rats were employed as controls.

d24-hour changes in circulating prolactin, follicle-stimulating hormone, luteinizing hormone and testosterone in male rats subjected to social isolation.

BACKGROUND: This work analyzes the effect of social isolation (a mild stressor) on the 24-h variation of pituitary-testicular function in young Wistar rats, assessed by measuring circulating levels of prolactin, FSH, LH and testosterone. METHODS: Animals were either individually caged or kept in groups (4-5 animals per cage) under a 12:12 h light-dark cycle (lights on at 0800 h) for 30 days starting on day 35 of life. Rats were killed at 4-h intervals during a 24-h cycle, beginning at 0900 h.

Changes of prolactin regulatory mechanisms in aging: 24-h rhythms of serum prolactin and median eminence and adenohypophysial concentration of dopamine, serotonin, (gamma-aminobutyric acid, taurine and somatostatin in young and aged rats.

Twenty-four hour rhythmicity of serum prolactin and median eminence and anterior pituitary content of dopamine (DA), serotonin (5HT), gamma-aminobutyric acid (GABA), taurine and somatostatin were examined in 2 months-old and 18-20 months-old Wistar male rats. The concentration of prolactin was higher in aged rats, with peaks in both groups of rats at the early phase of the activity span. Median eminence DA content of young rats attained its maximum at the middle of rest span and decreased as prolactin levels augmented while the lowest values of adenohypophysial DA were observed at the time of prolactin peak.

In vitro effect of melatonin on oxygen consumption in liver mitochondria of rats.

Objective: To examine the in vitro effect of melatonin on rat mitochondrial liver respiration.

Methods: Oxygen consumption by liver mitochondria was measured polarographically in the presence of one of the following Krebs' cycle substrates: Lsuccinate, DL-3- beta-hydroxybutyrate or L-malate. Respiratory velocities at rest (state 4) and during rapid respiration in the presence of substrate and adenosine diphosphate (state 3) were measured in the presence of 10 (-9)-10(-3) M concentrations of melatonin.

Effect of aging on 24-hour changes in dopamine and serotonin turnover and amino acid and somatostatin contents of rat corpus striatum.

This study examined the 24-hour changes in a number of transmitters in the corpus striatum of young and middle-aged male Wistar rats. The contents of excitatory amino acids (glutamate, aspartate) and inhibitory amino acids (gamma-aminobutyric acid, GABA; taurine, glycine) and of somatostatin were measured in 2-month- and 18- to 20-month-old rats killed at six different time points along the 24-hour cycle. The striatal serotonin and dopamine turnover was also measured.

Vascular reactivity in diabetic rats: effect of melatonin.

The aim of the present study was to evaluate the in vitro contractile response of rat aorta in mild and severe type I diabetes and the effect of melatonin on it. Aortic rings were obtained from male Wistar rats injected with streptozotocin 8-12 wks earlier. Rats were divided into three groups: non-diabetic rats (NDR), mildly diabetic rats (MDR) and severely diabetic rats (SDR).

Age-related changes in 24-hour rhythms of norepinephrine content and serotonin turnover in rat pineal gland: effect of melatonin treatment.

The 24-hour rhythms of pineal norepinephrine (NE) content and serotonin (5-HT) turnover [estimated from the ratio of 5-hydroxyindoleacetic acid (5-HIAA) to 5-HT] were studied in young (2 months) and aged (18-20 months) Wistar rats killed at 6 different time points throughout a 24-hour cycle. In the first study, significant changes dependent on the time of day were identified, with acrophases in the first half of the activity span for both parameters. Old rats showed significantly smaller mesor and amplitude of the 24-hour rhythm of pineal NE content.

Nighttime changes in norepinephrine and melatonin content and serotonin turnover in pineal glands of young and old rats injected with Freund's adjuvant.

Objectives: This study was performed to search for changes in rat pineal function attributed to age and immunization with Freund's adjuvant.

Methods: Young (2 months) and old (18-20 months) Wistar rats were injected s.c.

Age-dependent changes in 24-hour rhythms of catecholamine content and turnover in hypothalamus, corpus striatum and pituitary gland of rats injected with Freund's adjuvant.

Background: Little information is available on the circadian sequela of an immune challenge in the brain of aged rats. To assess them, we studied 24-hour rhythms in hypothalamic and striatal norepinephrine (NE) content, hypothalamic and striatal dopamine (DA) turnover and hypophysial NE and DA content, in young (2 months) and aged (18-20 months) rats killed at 6 different time intervals, on day 18th after Freund's adjuvant or adjuvant's vehicle administration.

Results: Aging decreased anterior and medial hypothalamic NE content, medial and posterior hypothalamic DA turnover, and striatal NE concentration and DA turnover.

Effect of melatonin on 24h changes in plasma protein levels during the preclinical phase of Freund's adjuvant arthritis in rats.

The 24h rhythms in plasma protein concentration were examined in rats on the third day after injection of Freund's complete adjuvant or adjuvant's vehicle, performed 3h after light on. In rats treated with adjuvant's vehicle, peak values of albumin and gamma globulin occurred during the nocturnal activity span (P < .02 and P < .

Extracellular acidification related to the stimulation of catecholamines release by strontium in the bovine adrenal medulla.

The possible modifications of extracellular pH associated with the secretion of catecholamines evoked by the introduction of 2.2 mM Sr2+ to a Ca(2+)-free, buffer-free, Locke solution were investigated in decorticated perfused bovine adrenal glands. A progressive and reversible decrease of external pH accompanied the catecholamine release promoted by Sr(2+)-introduction into the perfusion fluid.