295 resultados para Gonadal steroids
Resumo:
In order to study the divergence of teleost sex chromosomes, subtractive cloning was carried out between genomic DNA of males and females of the rainbow trout (XX/XY) and of Leporinus elongatus (ZW/ZZ). Inserts cloned in a plasmid vector were individually tested on Southern blots of DNA of males and females for sex specificity. No sex-specific insert was obtained from trout, but two out of ten inserts cloned from L. elongatus showed sex-specific patterns in this species: one corresponds to a sequence present on both Z and W chromosomes, while the other is W specific. Sequences of these two inserts show neither clear homology with other known sequences, nor an open reading frame. They cross-hybridize with the genomic DNA of Leporinus friderici, but without sex-specific patterns. Twenty-four L. elongatus adults were sexed by gonadal observation, chromosomed examination and Southern hybridization with one or the other insert. Ten males and 11 females had chromosomes and hybridization patterns typical of their sex. One ZW female was recognized as a male with the W-specific probe. This was also the case for two unusual ZW males, one having a male hybridization pattern with the other probe. These three atypical individuals may result from single genetic exchanges between four regions of the Z and the W, giving rise to three atypical W chromosomes. Finding males with such atypical heterochromosomes in a female heterogametic species may indicate that a gradual transition occurs between the heterogametic systems.
Resumo:
This paper reports the separation and identification of indole alkaloids, steroids and triterpenoids from the ethanolic extracts of Tabernaemontana hilariana (Apocynaceae). The alkaloidal fractions from the ethanolic extracts obtained (root barks, green fruits, ripe fruits and seeds) were fractionated and analysed by thin-layer chromatography, capillary gas chromatography-flame ionization detection (cGC-FID) as well as by high-resolution gas chromatography-mass spectrometry (HRGC-MS). 3-Hydroxycoronaridine, ibogamine, coronaridine pseudoindoxyl, coronaridine, catharanthine, voacangine hydroxyindolenine, voacangine pseudoindoxyl, tabernanthine, tetraphyllicine, 3-hydroxyvoacangine, voacangine, isovoacangine and 3-oxocoronaridine were identified. The insoluble fraction of ethanolic extracts obtained from the root barks and green fruits were analysed and ten aliphatic constituents were also identified by cGC-FID and HRGC-MS. (C) 1998 Elsevier B.V. B.V. All rights reserved.
Resumo:
Background: Therapy strategies for myelodysplastic syndromes (MDS) and juvenile myelomonocytic leukemia (JMML) vary considerably. Objective: To review the treatment of Brazilian children who were diagnosed with MDS or JMML in the past decade and reported to the Brazilian Cooperative Group on Pediatric Myelodysplastic syndromes (BCG-MDS-PED). Results: of 173 children reported to the BCG-MDS-PED from January 1997 to January 2003 with a suspected diagnosis of MDS or JMML, 91 had the diagnosis confirmed after central review of the bone marrow aspirate and biopsy. Information on previous treatments was available for 78 MDS/JMML patients. Treatment varied from different schedules of low-dose (14%) and standard-dose chemotherapy (50%), granulocyte-colony-stimulating factor (G-CSF 7%), interferon (5%), steroids (2%) and erythropoietin (2%) to allogeneic stem-cell transplantation (SCT) (14%). No survival advantage could be demonstrated based on Hasle's classification or based on treatment. Conclusion: This report reflects the current practice in treating Brazilian children with MDS/JMML without specific Cooperative Group guidelines. Treatment modalities were very heterogeneous. The strategies for implementing a national protocol should consider international guidelines and focus on local experience and available resources. (C) 2004 Elsevier Ltd. All rights reserved.
Resumo:
Dichloromethane extracts from twigs of Virola surinamensis (Myristicaceae) showed in vitro trypanosomicidal activity against trypomastigote form of Trypanosoma cruzi. The extract, fractionated by preparative circular chromatography and preparative high-performance liquid chromatography yielded two steroids, two lignans, five flavonoids, and one polyketide. Among the isolated compounds, the lignans presented the highest trypanosomicidal activity.
Resumo:
The objective of this work was to caracterize the morphological characterization of the development stages of male reproduction apparel of bullfrog Rana catesbeiana from intensive Anfigranja system. During the period of one year, 657 bullfrog males were removed from regrowing and reproduction sections in Anfigranja system to study basic aspects of the reproduction of this specie. The collections were realized monthly and, in that occasion, the body and testicles weights for each animal were recorded and their macroscopic gonadal characteristics, registred. Testicles from 274 males were removed and histologically analyzed. From the macro and microscopic gonadal characteristics, analysis set of the testicles, five stages of gonadal maturation for the male of Rana catesbeiana were determined: juvenile, beginning of maturation, intermediate maturation, advanced maturation and spent.
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
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.
Resumo:
A case of a 43-year-old nonobese woman with adiposis dolorosa (Dercum's disease) is reported. Muscle glucose uptake and oxidation before and after ingestion of 75 g of glucose were similar to control group values, although a greater insulin release (16,578 vs 6,242 +/- 1,136 muU/3 h) occurred simultaneously. In vitro studies of abdominal normal and painful subcutaneous adipose tissue of the patient revealed lower responsiveness to norepinephrine and lack of response to the antilipolytic effect of insulin in the painful adipose tissue (0.98 vs 1.43 muM FFA/10(6) cells at 5.0 muM of norepinephrine). The disease was not correlated with the HLA system and there were no alterations in hormonal secretion at the pituitary, adrenal, gonadal, and thyroid levels. These findings indicate the presence of peripheral insulin resistance in this patient with adiposis dolorosa.
Resumo:
Two novel acylated flavonol glycosides, along with iridoids, triterpenes, steroids and alpha-tocopherolquinone, were isolated from the leaves of Alibertia sessilis (Rubiaceae). The determination of the structures of the new compounds was based mainly on H-1- and C-13-NMR.
Resumo:
The influence of testosterone on the development of the pressor response to common carotid occlusion was investigated in control and median eminence-lesioned male rats. In control rats (N = 9), gonadectomy performed 21 days before the experiments reduced by 22% (from 51 +/- 2 to 40 +/- 2 mmHg) and treatment with testosterone (300-mu-g for 4 days before the measurements) increased the initial peak pressor response (from 51 +/- 2 to 57 +/- 2 mmHg) which depends on carotid innervation. The maintained response which is of central origin (probably ischemic) was less affected. In nongonadectomized rats (N = 6), lesions of the median eminence (6 days) decreased the initial peak by 19% (from 52 +/- 2 to 42 +/- 3 mmHg) and the maintained response by 56% (from 32 +/- 2 to 14 +/- 1 mmHg). Sham-operated rats served as controls. In gonadectomized animals (N = 6) the lesion reduced only the maintained response (from 23 +/- 2 to 11 +/- 1 mmHg). Testosterone supplementation restored the maintained response but did not alter the initial peak. These results indicate that the pressor response to common carotid occlusion in male rats is modulated by testosterone and that the depression in the maintained response caused by median eminence lesion can be reversed by steroid supplementation.
Resumo:
Chromatographic fractionation of the dichloromethane extract from roots of Virola surinamensis yielded two new natural products, 3-epi-juruenolide C and 2'-hydroxy-7,4'-dimethoxyisoflavone, as well as various known steroids, lignans, isoflavones, flavonoids and diarylpropanes. of these, alpha,2'-dihydroxy-4,3'-dimethoxydihydrochal biochanin A and 2'-hydroxy-7,4'-dimethoxyisoflavone displayed antifungal activity against Cladosporium cladosporioides at a minimum amount of 5 mu g, whereas 7-hydroxyflavanone and 7-hydroxy-4'-methoxyisoflavone exhibited an antifungal activity 10-fold higher than the positive control Nystatin. (C) 1999 Elsevier B.V. Ltd. All rights reserved.
Resumo:
The influence of fetal calf serum alone (FCS) or associated with proestrous (FCS+PCS), estrous (FCS+ECS) or metaestrous (FCS+MCS) cow serum added to the culture medium and of the steroids produced by co-cultured granulosa cells were evaluated in terms of the in vitro maturation (TVM) and fertilization (IVF) of bovine oocytes. Supplementation of the medium with FCS+ECS and FCS+MCS resulted in higher proportions of oocytes that reached metaphase II (96.0% and 93.3%, respectively) and in higher proportions of embryos that reached the four- and eight-cell/morula stages (51.9% and 65.6%, respectively), whereas the supplementation with FCS and FCS+PCS resulted in only 79.2% and 67.5%, respectively, of matured oocytes and 26.7% and 34.3%, respectively, of cleaved embryos. These findings show that the best IVM and IVF were obtained at lower concentrations of estradiol produced by co-cultured granulosa cells (supplementation with FCS+ECS: 10.3 ng/ml and FCS+MCS: 2.1 ng/ml), whereas the worst-results in IVM and IVF occurred at higher concentrations of estradiol that were obtained with FCS (33.1 ng/ml) and FCS+PCS (19.9 ng/ml) supplementation. These data suggest an inhibitory effect of estradiol on resumption of oocyte meiosis in vitro.
Resumo:
Genetic analyses of sex determination have identified sex chromosomes in many teleost fish species. However, there are several cases for which sex ratios do not fit perfectly with the expectations of heterogametic systems, suggesting the influence of either minor sex determining genes or environmental influences on the process of sex differentiation. The frequent absence of sex chromosome markers makes the identification of minor sex-determining genes very difficult. It is easier to test first the hypothesis of environmental sex determination (ESD) by studying the temperature effect, since temperature-dependent sex determination has been demonstrated to occur in several vertebrate groups including 1 fish species. To contribute to a better understanding of fish sex determination, we have tested the effects of high temperatures on sex ratios of Oreochromis niloticus, and have attempted to isolate sex chromosome molecular markers in Leporinus elongatus. Treatments of O. niloticus fry at 36 degrees C applied for 10 days and more, and starting 1 week after fertilization markedly increased the proportion of males, and progeny-testing these males confirmed that some of them are sex-reversed genetic females. Two non-coding sequences of L. elongatus Z and W chromosomes were cloned by genomic subtraction. They cross-hybridized with the genome of a close species without providing sex-specific patterns. A collection of L. elongates individuals was subjected to gonadal and chromosomal sexing, and DNA hybridization with both sequences. These analyses revealed 3 individuals having atypical W chromosomes. Interestingly, 2 of these were males having a ZW karyotype. We assume that these atypical sex chromosome arise by exchanges between Z and W chromosomes, and that a transition between female and male heterogamety is underway in this species.
Resumo:
From stems of Aristolochia chamissonis Duch., five new diterpenes, one rearranged (4 --> 2)-abeo-clerodane and four ent-clerodanes, were isolated. Their structures were determined to be (+)-(4 --> 2)-abeo-kolavelool-3-oic acid, (-)-13-epi-2-oxokolavelool, (-)-2 beta-hydroxykolavelool, (-)-2 beta-hydroperoxykolavelool and (+)- 13-epi-2 alpha-hydroxykolavelool. In addition, lignans, sesquiterpenes, steroids and two known ent-clerodane diterpenes were isolated. (C) 1998 Elsevier B.V. Ltd. All rights reserved.
Resumo:
A. suite of 10 different marine evaporitic oil samples from Sergipe-Alagoas Basin, Brazil was studied for its biomarker content, in particular its acidic constituents. The oils showed different molecular distributions and relative abundances of n-alkanoic, isoprenoid and hopanoic acids. The observed differences were assigned to the incorporation of immature organic matter in the oils and fractionation along the migration pathway. The diagenetic precursor functionality (alcohol/ether or acid) was proposed based on the comparison of the relative abundances of the neutral and acidic biomarkers (hopanoids, isoprenoids, alkyl-steranes, monoaromatic alkyl-steroids). In the acidic fraction, 3 series of steroid-alkanoic acids and monoaromatic steroid-alkanoic acids (steroid-methanoic, ethanoic and propanoic acids and monoaromatic steroid-methanoic, ethanoic and propanoic acids) were detected, while in the neutral fraction only 2 series of each corresponding class could be observed (methyl and ethyl-steranes and monoaromatic methyl and ethyl-steroids). These carbon shifts suggest that decarboxylation is an important process in the formation of the alkyrsteranes and monoaromatic alkyl-steroids, and we infer that carboxylic acids are the diagenetic precursors of these classes of compounds. When alcohol or ether are the diagenetic precursors (isoprenoids and hopanoids), no significant differences in the molecular distributions between neutral and acidic fractions were observed. (C) 2000 Elsevier B.V. Ltd. All rights reserved.