Cinética dos anticorpos de origem colostral contra a toxina épsilon de Clostridium perfringens tipo D em cordeiros

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cholinergic responses of seminal vesicles isolated from rats exposed perinatally to hydrocortisone

This study was performed in order to investigate the cholinomimetic response of seminal vesicles isolated from rats treated with hydrocortisone acetate during perinatal life. At the adult phase, the body weight and the wet weight of the seminal vesicle of these animals were unchanged. However, these male rats exhibited a significant reduction in plasma testosterone concentration. A significant increase in the sensitivity of the seminal vesicle to acetylcholine was also observed. Despite this, there was a significant reduction in the maximum contractile response of the organ to this transmitter. These results indicate that exposure to hydrocortisone during the critical period of brain sexual differentiation has a long-term effect on testosterone production of male rats. In addition, physiological levels of cortisone in perinatal life are also essential to support the contractile response pattern of the seminal vesicle to acetylcholine in adult life, probably crucial to the reproductive process. (C) 2003 Elsevier B.V. Ltd. All rights reserved.

Puberty installation and adrenergic response of seminal vesicle from rats exposed prenatally to hydrocortisone

We investigated the effects of hydrocortisone during the prenatal period and its repercussion on puberty installation and adrenergic response of seminal vesicle in adult rats. The efficacy of the hydrocortisone treatment in reducing adrenal wet weight immediately after delivery in both the treated mothers and respective pups at birth may indicate impairment of the hypothalamus-pituitary-adrenal axis. This parameter was unchanged in the adult phase of these descendants, suggesting recuperation of this axis. In addition, the treatment with hydrocortisone delayed the age of puberty installation, probably by absence of both physiologic production and liberation of luteinizing hormone and testosterone. Despite the significant reduction in testosterone level as well as of wet weights of both vas deferens and testis in the adult phase, no difference was observed in the sensitivity of the seminal vesicle to the studied sympathetic agonist. However, the observed reduction in contractile response of the seminal vesicle may be a consequence of contractile-system damage in this organ. It is possible that this alteration may cause a reduction in the amount of vesicular secretion so important in the process of ejaculation. In conclusion, these results suggest that administration of hydrocortisone in late prenatal life did not influence the hypothalamus-pituitary-adrenal axis in adult life, although it altered the hypothalamus-pituitary-gonadal axis, and reduced testosterone production starting at puberty, as a consequence of an incomplete masculinization of the hypothalamus plus a reduction in the contractile response of the seminal vesicle. (c) 2005 Elsevier B.V. All rights reserved.

5alpha-reductase 2 inhibition impairs brain defeminization of male rats: Reproductive aspects

The present study was carried out to determine whether 5alpha-reductase 2 (5alpha-R2) metabolic pathway plays a key role in brain sexual differentiation. The inhibition of 5alpha-R2 by finasteride (20 mg/kg/day) from gestational day 19 to postnatal day 5 has long-term effects on sexual behavior and reproductive physiology detected only in adult life. Sexual maturation assessed by timing of preputial separation was unchanged. Finasteride-treated males were able to mate with untreated females which became pregnant but exhibited increased rate of pre-implantation loss. The subfertility observed was probably due to abnormally shaped sperm, since the sperm number was not altered. While plasma testosterone was enhanced, LH levels were not changed. The copulatory potential was not affected and all finasteride-treated rats presented male sexual behavior. Despite this, 53% of them showed homosexual behavior when pretreated with estradiol, suggesting an incomplete brain defeminization. These results indicate that 5alpha-R2 acts in brain sexual differentiation of male rats. Moreover, we suggest that 5alpha-R2 not only produces essential metabolites that act together with estradiol in brain sexual differentiation but also protects the brain from the damaging effects of estradiol excess. (c) 2005 Elsevier B.V. All rights reserved.

Effects of neonatal clomiphene citrate on fertility and sexual behavior in male rats

In order to investigate the participation of estrogen during the period of brain sexual differentiation, male rats were treated with clomiphene citrate in the neonatal phase. Fertility and sexual behavior were assessed during adult life. Sexual maturation, body weight, and wet weight of the testes were unchanged. Although the adult male rats treated with clomiphene in the neonatal phase presented a significant reduction in the frequency of mounts, 90% of these rats were able to mate with normal females, which became pregnant. However, these females exhibited a significantly increased number of pre- and post-implantation losses. When these adult male rats were castrated and received estrogen, 60% presented female sexual behavior (receptive behavior and acceptance of mount). Thus, treatment of pups with clomiphene immediately after birth has a long-term effect on the reproductive physiology and sexual behavior of male rats. (C) 2002 Elsevier B.V. All rights reserved.

Anti-poliovirus activity of Baccharis dracunculifolia and propolis by cell viability determination and real-time PCR

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A morphometric study of the mud crab, Panopeus austrobesus Williams, 1983 (Decapoda, Brachyura) from a subtropical mangrove in South America

The relative growth of the xanthid crab, Panopeus austrobesus was investigated by means of the allometric method. Crabs were obtained in the mangrove formed by the estuary of the rivers Comprido and Escuro (23degrees29'24S 45degrees10'12W), Ubatuba, São Paulo State, Brazil. All crabs were measured to obtain their carapace width (CW) and length (CL), abdomen width (AW) at the basis of the 5(th) somite, and major cheliped propodus length (PL) and height (PH). Males were also measured for their gonopod length (GL). The size of crabs based on CW ranged from 4.0 to 44.8 mm for males and 3.1 to 34.5 mm for females. The relative growth equation (Y = aX(b)) based on the relationship between GL and CW suggested that males reach their sexual maturity near 14.6 mm CW. Such relationship shows a positive allometry during the juvenile phase and an isometric growth in adult life. In females, the estimated size at 50% maturity is 13.0 mm CW, based on the relationship AW vs. CW. Males reach larger sizes than females, which probably provides them better conditions to protect females during courtship. Concerning cheliped size, approximately 73% of the crabs analysed (N = 209), disregarding sex, have the right PL larger than the left. The PL growth shows that specimens with a left major cheliped (26%) have a higher allometric coefficient, despite being smaller considering their CW. Such a difference may compensate the smaller size of the crab during defense or prey capture.

Alterations induced by the juvenile hormone in glandular cells of the Apis mellifera venom gland: Applications on newly emerged workers (Hymenoptera, Apidae)

Histological and histochemical analyses were carried out in order to evaluate the influence of the topical application of a synthetic juvenile hormone on the secretory cycle and degeneration of the venom gland of Apis mellifera. Newly emerged workers received the topical application of synthetic hormone and the results were compared to the normal development of the secretory cycle in virgin and mated queens. The first worker group received the juvenile hormone diluted in hexane (2 mu g/mu L), the second received only mu L of hexane, and the third did not receive any kind of application. After the application the workers were returned to the colony and collected at the ages of 14 and 25 days of adult life. The groups with virgin queens and the other with mated queens, did not receive the treatment. The results show that the individuals treated with juvenile hormone and with pure hexane presented differences in the histological and cytochemical aspects of the secretory cells of the venom gland. The data indicate that both the juvenile hormone and hexane accelerate the activity of the secretory cycle and the degeneration of the venom gland; however, the juvenile hormone proved to be more effective than hexane. (c) 2006 Elsevier Ltd. All rights reserved.

Tissue evidence of the testosterone role on the abnormal growth and aging effects reversion in the gerbil (Meriones unguiculatus) prostate

Prostate differentiation during embryogenesis and its further homeostatic state maintenance during adult life depend on androgens. Abundant biological data suggest that androgens play an important role in the development of the prostate cancer and other prostatic diseases. The objective of this work was to evaluate the effects of the testosterone supplementation in gerbil (a new experimental model) at different ages. Tissues from experimental animals were studied by histological and histochemistry procedures, androgen receptor immunohistochemistry assay, morphometric-stereological analysis, and transmission electron microscopy (TEM). After the treatment were observed increase of prostate weight and epithelium height in all ages studied. In some adult and aged treated animals, hyperplasic and displasic process were observed, including prostatic intraepithelial neoplasias and adenocarcinomas. Increase of the thickness of the smooth muscle cell (SMC) layer was observed in pubescent and adult animals and TEM revealed apparent SMC hypertrophy. An apparent increase in the frequency of blood vessels distributed by the subepithelial stroma in the treated animals was noticed. Reversion of the natural effects of aging on the prostate was observed in the aged treated animals in some acini of the gland. These data demonstrate that the gerbil prostate is susceptible to androgenic action at the studied ages and it can serve, for example, as experimental model to studies of prostate neoplasic process induction and hormonal therapy in aged animals.

Environmental evaluation of metals in sediments and dragonflies due to sugar cane cultivation in neotropical streams

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

O México como aliado dos EUA no projeto de integração das Américas

O artigo sugere que, nas duas últimas décadas, os governos mexicanos vêm adotando medidas políticas e econômicas amplamente afinadas com o modelo de integração econômica das Américas proposto pelos EUA. A adesão incondicional ao Nafta e o empenho para consolidar os projetos do Corredor Biológico Mesoamericano e do Plano Puebla-Panamá são exemplos fundamentais dessa estratégia.

Oil-soluble dyes for marking Spodoptera frugiperda (Lepidoptera : Noctuidae)

Although various biological aspects of Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) have been examined, adult movement and dispersal of this insect pest is not well understood. Release-recapture techniques by using marked insects is a useful approach for dispersal studies; however, the marking technique should not significantly affect insect biology or behavior. Therefore, the effect of different concentrations of oil-soluble dyes (Solvent Blue 35 [C.I. 61554], Sudan Red 7B [C.I. 26050], Sudan Black B [26150], Sudan Orange G [C.I. 11920], and Sudan I 103624 [C.I. 12055]) on development, mortality, and fecundity of S. frugiperda was evaluated. Dyes were added to artificial diet used to feed larvae. Larval and pupal development and mortality, adult longevity, and female fecundity were evaluated. High concentrations (400 and 600 ppm) of all dyes led to longer larval and pupal stages. Adult life span and number of eggs were not affected by the dyes. Sudan Red 7B marked both adults and eggs very well. Solvent Blue 35 marked both adults and eggs, but the blue-marked eggs could not be distinguished from some bluish eggs laid by nonlabeled females. Adults and eggs were not adequately marked by the Sudan Black B, Sudan Orange G, and Sudan I 103624 (a yellow dye).

Puberty and growth rate in thoroughbred fillies

We measured progesterone and estradiol levels from birth to the beginning of adult life in 10 Thoroughbred fillies from the Equilia Stud Farm in Avare SP, Brasil. The animals were measured and weighed monthly for the determination of body development and of a possible correlation between the rate of weight and height gain and the onset of detectable sex hormone levels. Jugular blood was collected twice a week and stored at -20 degrees C until assay of progesterone by a solid phase RIA with a sensitivity of 0.32 nmol/L and of estradiol by liquid phase RIA adapted to low levels (3.67 pmol/L). The fillies were born with high serum levels of both hormones,which fell to undetectable levels by the first week of life. A variation in growth rate was observed, with the highest levels occuring from birth to the 3rd month of life, followed by a reduction until 15 mo of life, when fast growth was resumed. The monthly weight gain was 1.5% when the fillies reached puberty and 5.4% during the next month, (P<0.05, Friedman test). During this second period of accelerated growth after the beginning of progesterone production at detectable levels (above 0.318 nmol/L), the parameters of skeletal growth did not differ (P>0.05). The month of onset of puberty was the month of lowest weight gain in the life of the fillies, and it coincided with the highest insolation period. In conclusion, horses, like all other developed vertebrates, have a double pattern of development, with the acceleration observed at puberty depending on sex steroids, which in turn coincides with the highest insolation period. Gonadal activity characterized by serum progesterone levels was low from birth to the onset of puberty. After puberty the progesterone cycles were similar to those of adult animals with a mature hypothalamic-gonadal axis. (C) 1997 by Elsevier B.V.

Reproductive aspects in female rats exposed prenatally to hydrocortisone

We investigated the effects of hydrocortisone during the prenatal period and its later repercussion on reproductive aspects of female rats. Pregnant rats were treated (s.c.) with hydrocortisone acetate, at 1.5 mg/day on the 17th, 18th, and 19th days of pregnancy. Although the present study was not intended to identify mechanisms of toxicity, the treatment with hydrocortisone in the last period of pregnancy presented no signs of toxicity. The efficacy of the hydrocortisone in reducing the adrenal wet mass and plasma corticosterone levels immediately after delivery in both the treated mothers and in respective pups at birth may indicate impairment of the hypothalamus-pituitary-adrenal axis. In addition, the treatment with hydrocortisone did not interfere in the development of the female descendants until puberty. However, it affected the estrous cycle and fertility, Probably, the prenatal exposure to corticosteroids had altered at least partially the hypothalamus-pituitary-gonadal axis, resulting in the damages observed in adult life. These results indicate that the use of the hydrocortisone at a dose that apparently does not endanger the neonate led to undesirable effects in the adult reproductive phase, resulting in later deleterious alteration of the reproductive physiology in female rats. (C) 2004 Elsevier B.V. All rights reserved.

Torpor in three species of Brazilian hummingbirds under semi-natural conditions

We measured body temperatures in three species of Brazilian hummingbirds, the Versicolored Emerald (Amazilia versicolor; body mass 4.1 g), the Black Jacobin (Me lantrochilus fuscus; body mass 7.7 g) and the Swallow-tailed Hummingbird (Eupetomena macroura; body mass 8.6 g), during overnight exposure to natural conditions of photoperiod and ambient temperatures. All three species entered torpor. In both A. versicolor and E. macroura, individuals entered torpor even if they had access to feeders up to the time of sunset. In contrast, M. fuscus was less prone to enter torpor and did so mainly if it had been fasting for more than two hours before sunset. Furthermore, M. fuscus often spent the whole night in torpor, whereas the two other species entered torpor for a variable, often short, period of the night. We observed more than one torpor bout during a single night in all three species. We suggest that multiple nocturnal torpors result from interruption of the normal torpor pattern by some (unknown) external stimuli. Any interrupted torpor was always followed by a new entry into torpor, supporting the view that there is a body mass threshold below which the hummingbirds must enter torpor Our data also indicate that these hummingbird species might use torpor even if they are not energetically stressed.