958 resultados para Iniciação cientifica
Resumo:
1. Adrenal ectopic tissue has been detected in the paragonadal region of normal women. In patients with congenital adrenal hyperplasia due to 21-hydroxylase (21-OH) deficiency, the manifestation of hyperplasia of paragonadal accessory adrenal tissue has been usually reported to occur in males. Probably, this is the first report of a female with 3beta-hydroxysteroid dehydrogenase (3beta-HSD) deficiency with ectopic adrenal tissue in ovaries. However, the occurrence of hyperplasia of adrenal rests among women with classical congenital adrenal hyperplasia may not be rare, especially among patients with a late diagnosis.2. We report a woman with 3beta-HSD deficiency whose definitive diagnosis was made late at 41 years of age immediately before surgery for the removal of a uterine myoma. During surgery, exploration of the abdominal cavity revealed the presence of bilateral accessory adrenal tissue in the ovaries and in the para-aortic region. The patient had extremely high levels of ACTH (137 pmol/l), DHEA (901.0 nmol/l), DHEA-S (55.9 mumol/l), androstenedione (70.2 nmol/l), testosterone (23.0 nmol/l) and 17alpha-hydroxypregnenolone (234.4 nmol/l) suggesting 3beta-HSD deficiency.3. In view of these elevated androgen levels, with an absolute predominance of DHEA and DHEA-S, we evaluated the effect of this hormonal profile on carbohydrate tolerance and insulin response to glucose ingestion.4. The patient presented normal glucose tolerance but her insulin response was lower than that of 14 normal women (area under the curve, 3beta-HSD = 17,680 vs 50,034 pmol/l for the control group over a period of 3 h after glucose ingestion).5. These results support recent data suggesting that patients with increased serum DHEA and DHEA-S levels do not present resistance to insulin.
Resumo:
Amitraz, a formamidine insecticide and acaricide used in veterinary practice, presents side effects related to its pharmacological activity on az-adrenergic receptors. The present study was undertaken to investigate the antinociceptive effect of amitraz in rats and mice. The tail-flick test was used to determine the duration of the antinociceptive effect of the intraperitoneal tip) administration of amitraz (1 and 2 mg/kg, 10 animals per group) in male Wistar rats weighing 180-220 g. The writhing test (using 10 ml/kg of a 0.6% acetic acid solution as a painful stimulus). was performed in 140 male Swiss mice weighing 20-30 g, divided into 14 groups that received ip injections of saline, amitraz (0.5, 1.0, 1.5, 2.0 and 4.0 mg/kg), xylazine or detomidine (1.0, 1.5, 2.0 and 4.0 mg/ kg), in order to compare the effect of amitraz to that caused by xylazine and detomidine, and to investigate the participation of alpha(2)-adrenergic receptors which were blocked by idazoxan (1 mg/kg). Amitraz induced a significant antinociceptive effect in both rats and mice. This effect is blocked in mice by idazoxan.
Effect of pancreas transplantation on the prevention of nephropathy in alloxan-induced diabetic rats
Resumo:
We studied the effects of pancreas transplantation on kidney lesions of rats with alloxan-induced diabetes. Ninety inbred male Lewis rats were randomly assigned to 3 experimental groups: group NC included 30 non-diabetic control rats, group DC included 30 alloxan-induced diabetic control rats, and group PT included 30 alloxan-induced diabetic rats that received pancreas transplants from normal donor Lewis rats. Each group was further divided into 3 subgroups of 10 rats which were sacrificed at 1, 3, and 6 months of follow-up, respectively. Clinical and laboratory parameters during these periods were documented. The kidneys of 5 rats in each subgroup were studied and 50 glomeruli and tubules from each kidney were analyzed by light microscopy by two different investigators in a double-blind study. There was progressive glomerular basement membrane thickening (GBMT), mesangial enlargement (ME), and Bowman's capsule thickening (BCT) in kidneys of rats in the 3 experimental groups during follow-up. These alterations were significantly higher in DC rats (GBMT: 1.99 +/- 0.31; ME: 2.00 +/- 0.33; BCT: 1.88 +/- 0.27) when compared to NC(GBMT: 1.54 +/- 0.30; ME: 1.56 +/- 0.47; BCT: 1.36 +/- 0.35) and PT rats (GBMT: 1.49 +/- 0.29; ME: 1.57 +/- 0.36; BCT: 1.35 +/- 0.28) at 6 months (P<0.01). The extent of GBMT, ME, and BCT observed in DC rats at 1 and 3 months was not significantly different from NC and PT rats. The amount of kidney lesions in PT rats was similar to that of NC rats and lower than those of DC rats at 6 months (P<0.01). In addition, Armanni-Ebstein lesions of the tubules (AE) and tubular lumen protein (PRO) observed in DC rats were not present in NC or PT rats. We conclude that pancreas transplantation in alloxan-induced diabetic rats prevents the development of kidney lesions beginning at 6 months after transplantation.
Resumo:
We tested the effects of estradiol, progesterone and testosterone on water and salt intake induced by angiotensin II (ANG II) injected into the third ventricle of female Holtzman rats weighing 250-300 g. The water and salt ingestion observed after 120 min in the control experiments (injection of 0.5 mu l of 0.15 M NaCl into the third ventricle) was 1.6 +/- 0.3 ml (N = 10) and 0.3 +/- 0.1 ml (N = 8) in intact rats, respectively, and 1.4 +/- 0.3 ml (N = 10) and 0.2 +/- 0.1 (N = 8) in ovariectomized rats, respectively. ANG II injected in intact rats (4, 6, 12, 25, and 50 ng, icv, in 0.5 mu l saline) induced an increase in water intake (4.3 +/- 0.6, 5.4 +/- 0.7. 7.8 +/- 0.8, 10.4 +/- 1.2, 11.2 +/- 1.4 ml/120 min, respectively) (N = 43). The same doses of icv ANG II in intact rats increased the 3% NaCl intake (0.9 +/- 0.2; 1.4 +/- 0.3, 2.3 +/- 0.4, 2.2 +/- 0.3. and 2.5 +/- 0.4 ml/120 min, respectively) (N = 42). When administered to ovariectomized rats ANG II induced comparable amounts of water intake (4.0 +/- 0.5, 4.8 +/- 0.6, 6.9 +/- 0.7. 9.6 +/- 0.8, and 10.9 +/- 1.2 ml/120 min, respectively) (N = 43) but there was a significant decrease of 3% NaCl solution ingestion (0.3 +/- 0.1, 0.4 +/- 0.1, 0.8 +/- 0.2, 0.7 +/- 0.2, and 0.6 +/- 0.2 ml/120 min, respectively) (N = 44). Estrogen (50 mu g), progesterone (25 ng), and testosterone (300 mu g) were injected daily into ovariectomized rats for 21 days. Treatment with estrogen decreased the water intake and abolished the saline ingestion induced by icy injection of ANG II (12 ng (2.8 +/- 1.2 and 0.3 +/- 0.1 ml/120 min, respectively) (N = 8). Treatment with progesterone also reduced the water intake (3.3 +/- 0.6 ml/120 min) (N = 8) and abolished the ANG II-induced saline ingestion (0.4 +/- 0.1 ml/120 min) (N = 8), but these effects were not observed with testosterone (6.4 +/- 0.8 and 2.2 +/- 0.3 ml/120 min, respectively) (N = 8). These results indicate that ANG II induces a greater increase in sodium intake in intact female rats than in ovariectomized rats and that estrogen and progesterone impair water and sodium intake in ovariectomized rats.
Resumo:
1. A method for obtaining the end-systolic left ventricular (LV) pressure-diameter and stress-diameter relationships in man was critically analyzed.2. Pressure-diameter and stress-diameter relationships were determined throughout the cardiac cycle by combining standard LV manometry with M-mode echocardiography. Nine adult patients with heart disease and without heart failure were studied during intracardiac catheterization under three different conditions of arterial pressure, i.e., basal (B) condition (mean +/- SD systolic pressure, 102 +/- 10 mmHg) and two stable states of arterial hypertension (H(I), 121 +/- 12 mmHg; H(II), 147 +/- 17 mmHg) induced by venous infusion of phenylephrine after parasympathetic autonomic blockade with 0.04 mg/kg atropine.3. Significant reflex heart rate variation with arterial hypertension was observed (B, 115 +/- 20 bpm; H(I), 103 +/- 14 bpm; H(II), 101 +/- 13 bpm) in spite of the parasympathetic blockade with atropine. The linear end-systolic pressure-diameter and stress-diameter relationships ranged from 53.0 to 160.0 mmHg/cm and from 97.0 to 195.0 g/cm3, respectively.4. The end-systolic LV pressure-diameter and stress-diameter relationship lines presented high and variable slopes. The slopes, which are indicators of myocardial contractility, are susceptible to modifications by small deviations in the measurement of the ventricular diameter or by delay in the pressure curve recording.
Resumo:
The LH-RH analog LH-RH-A (des-Gly10,[D-Trp6]-LH-RH ethylamide) was administered in pharmacological doses (20-mu-g/kg, sc) to adult male cats for 15 days and its effect on testis and adrenal function was determined. Daily administration of the analog promoted a 3-fold increase in plasma testosterone levels after 7 days, indicating a stimulatory effect of LH-RH-A (mean +/- SD for 6 treated cats, 1.88 +/- 0.35 vs 0.51 +/- 0.08 ng/ml for 6 control cats). After 15 days the LH-RH-A-treated group exhibited a similar plasma testosterone concentration as the control group (mean +/- SD, 0.96 +/- 0.35 ng/ml vs 0.88 +/- 0.39 ng/ml, respectively), similar testicular and adrenal weights and no significant differences in the spermatogenic process. However, semiquantitative analysis of the zona fasciculata of the adrenals from the LH-RH-A-treated group showed a significant accumulation of a substance not stained by hematoxylin-eosin or Schiff periodic acid (mean +/- SD of index of accumulation was 3.50 +/- 0.4 for treated cats vs 2.20 +/- 0.3 for control cats). The present results show that pharmacological doses of LH-RH-A have an effect on the adrenal cortex of cats without modifying spermatogenesis or plasma testosterone levels.
Resumo:
The involvement of opioid receptors in the analgesic response was evaluated by the tail-immersion test in simultaneously adrenalectomized and ovariectomized female Wistar rats (210-250 g). The reaction time (mean +/- SEM) for tail withdrawal from hot water decreased significantly 2 weeks after surgery (3.52 +/- 0.20 s) when compared to intact animals (6.09 +/- 0.23 s). Hormonal replacement with dexamethasone (50-mu-g/day) did not affect reaction time (3.38 +/- 0.19 s). However, this response was restored by combined adrenal and gonadal steroid substitution (estradiol 5-mu-g/day and progesterone 1.5-mu-g 6 h before the tests) therapy (5.11 +/- 0.45 s in animals treated with dexamethasone plus estradiol and 5.04 +/- 0.43 s in animals treated with dexamethasone plus estradiol plus progesterone). Naloxone (2 mg/kg) decreased the reaction time of animals treated with adrenal and gonadal steroids (5.11 +/- 0.45 vs 4.15 +/- 0.44 s and 5.04 +/- 0.43 vs 3.87 +/- 0.28 s, respectively, before and after naloxone) but failed to decrease it in rats treated with dexamethasone only (3.88 +/- 0.18 vs 4.34 +/- 0.25 s, before and after naloxone). These observations indicate that gonadal steroids are the most important steroid factors involved in the reaction time to tail immersion in hot water and confirm other reports that the opioid pathways modulating the neuronal circuitry require the presence of these hormones.