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The aim of this work was to determine the effect of aging and gender on plasma norepinephrine (NE) response to orthostatic stress. Fifty-six men and sixty women non-smokers, sedentary, non-obese, were studied at supine and standing positions. On the basis of the age of the subjects, they were divided into three groups of either men or women. Group A, young, range 17-34 years, Group B, middle-age, range 40-60 years, and Group C: senescent, range 61-91 years. Senescent subjects had the highest absolute supine values of NE and significant differences between women and men were found in groups B Men: 298 +/- 15 pg/mL; Women: 348 +/- 14 pg/mL), and C (M: 386 +/- 29 pg/mL; W: 473 +/- 19 pg/mL), but not between young (M: 246 +/- 21 pg/mL; W: 261 +/- 18 pg/mL). NE increased markedly in response to the orthostatic stress but the relative (percentage) increases were smaller in the older subjects perhaps related to their elevated baseline levels. The highest percent positive variation was observed in group A (M: 85%; W: 82%). The oldest group (C), had the lowest variation (M: 23%; W: 21%). The relative increases in NE responses were not different in men and women. The orthostatic-induced variation in NE was negatively related to aging in both men and women (M: r = -0.654; p < 0.0001; W: r = -0.557; p < 0.0001). It is concluded that orthostatic stress induced rise of blood NE is attenuated by age but does not appear to be dependent on gender.

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The prevalence and clinical significance of leukocytes (WBC) and immature germ cells in semen is currently a matter of controversy. The aim of this work was to assess the prevalence of leukocytospermia in semen samples from Venezuelan men and its possible effects on sperm parameters. The concentration of WBC and round cells (RC) was evaluated in 118 semen samples from 19 fertile subjects (group 1), 62 infertile patients (group II), and 37 men with varicocele (group III). Semen WBC concentration was assessed by peroxidase assay. Twenty-six (22%) of the total samples had more than 10 WBC/mL semen. Twenty of the infertile men had leukocytospermia (32%) compared with 16% in the fertile group and 8% in the varicocele group. Semen RC concentration was lower than 5 x 10(6)/mL in all groups but, in groups II and III was significantly higher compared with group I. Infertile men had the highest WBC concentration. WBC concentration was negatively correlated with progressive motility, percentage of morphologically normal sperm, and hypoosmotic swelling test in infertile men but not in the varicocele group. In this group a negative correlation was obtained between immature germ cells and normal sperm morphology. The data show that leukcytospermia occurs frequently in infertile patients and is associated with poor semen quality parameters. In contrast, in men with varicocele, the increased number of immature germ cells might play a pivotal role in the pathogenesis of abnormal spermatozoa.

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We administered arecoline to rats, with experimentally induced chagasic myocarditis, in order to study the sinus node sensitivity to a muscarinic agonist. Sixteen month old rats were inoculated with 200,000 T. cruzi parasites ("Y" strain). Between days 18 and 21 (acute stage), 8 infected rats and 8 age-matched controls received intravenous arecoline as a bolus injection at the following doses: 5. 0, 10.0, 20.0, 40.0, and 80.0 microg/kg. Heart rate was recorded before, during and after each dose of arecoline. The remaining 8 infected animals and 8 controls were subjected to the same experimental procedure during the subacute stage, i.e., days 60 to 70 after inoculation. The baseline heart rate, of the animals studied during the acute stage (349 +/- 68 bpm, mean +/- SD), was higher than that of the controls (250 +/- 50 bpm, p < 0.005). The heart rate changes were expressed as percentage changes over baseline values. A dose-response curve was constructed for each group of animals. Log scales were used to plot the systematically doubled doses of arecoline and the induced-heart rate changes. The slope of the regression line for the acutely infected animals (r = - 0.99, b =1.78) was not different from that for the control animals (r = - 0.97, b = 1.61). The infected animals studied during the subacute stage (r = - 0.99, b = 1.81) were also not different from the age-matched controls (r = - 0.99, b = 1.26, NS). Consequently, our results show no pharmacological evidence of postjunctional hypersensitivity to the muscarinic agonist arecoline. Therefore, these results indirectly suggest that the postganglionic parasympathetic innervation, of the sinus node of rats with autopsy proved chagasic myocarditis, is not irreversibly damaged by Trypanosoma cruzi.

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The study comprised 323 cryptorchidic boys, between 6 months and 14 years of age (mean age 5.68 years) with 440 maldescended testes. Testicular position was graded as inguinal low or prescrotal (I), inguinal middle (II), inguinal high (III), and abdominal testes (IV). Boys before 4 years of age received human chorionic gonadotropin (hCG) as intramuscular injections (I.M.), 500 IU twice a week for 5 weeks; and boys 4 or more years of age received hCG (IM), 1000 IU twice a week for 5 weeks. The objectives of this study were to evaluate the response of maldescended testes to treatment with hCG, and to investigate possible associations between the patients' ages and position of the testes with the response to hCG. Out of the 440 maldescended testes, 329 were in an inguinal location (75%) and 111 were abdominally located (25%). The overall response to hCG was 40%, and the inguinal testes response was 49%, with the highest success rates (72%) for the prescrotal testes. A positive correlation was found (p < .0001) between the rate of success and the testicular position. There was no association between the hCG response and the age at which treatment was initiated.

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We studied the functional reserve of Leydig cells in adult rats of different ages in vitro. Suspensions of Leydig cells after digestion by collagenase were stimulated with Human Chorionic Gonadotropin (hCG) during different times (1, 3 and 5 hours). We observed that response of Leydig cells, expressed by the testosterone concentration in the culture medium, showed a similar pattern in all studied group, and the highest response was seen at three hours of incubation. On the other hand, the testosterone response to hCG varied with age of animal. Thus, it was higher in the group of 14 months old (middle aged) than young animals (5 month old) and decreased in old animals (21 months old). These results suggest that a primary testicular lesion occurs with aging.

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