Testosterone-immunopositive primordial germ cells in the testis of the bullfrog, Rana catesbeiana

In amphibia, steroidogenesis remains quiescent in distinct seasonal periods, but the mechanism by which spermatogenesis is maintained under low steroidogenic conditions is not clear. In the present study, testosterone location in the testes of Rana catesbeiana was investigated immunohistochemically during breeding (summer) and nonbreeding (winter) periods. In winter, the scarce interstitial tissue exhibited occasional testosterone immunopositivity in the interstitial cells but the cytoplasm of primordial germ cells (PG cells) was clearly immunopositive. By contrast, in summer, PG cells contained little or no immunoreactivity whereas strong immunolabelling was present in the well-developed interstitial tissue. These results suggest that PG cells could retain testosterone during winter. This androgen reservoir could be involved in the control of early spermatogenesis in winter and/or to guarantee spermiogenesis and spermiation in the next spring/summer. The weak or negative immunoreaction in the summer PG cells might reflect consumption of androgen reservoir by the intense spermatogenic activity from spring to summer. Thus, besides acting as stem cells, PG cells of R. catesbeiana could exert an androgen regulatory role during seasonal spermatogenesis.

Germ line Cysts and the Formation of the Germinal Epithelium During the Female Gonadal Morphogenesis in Cyprinus Carpio (Teleostei: Ostariophysi: Cypriniformes)

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

Cytotoxic effects of permethrin in oocytes of Rhipicephalus sanguineus (Acari: Ixodidae) fully engorged females: I. Direct or indirect action of the acaricide in germ cells?

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

Ultrastructural aspects of the intercellular bridges between female bee germ cells

No ovário das abelhas as células germinativas e as células foliculares são interconectadas por pontes intercelulares mantidas abertas por reforços do citoesqueleto na membrana plasmática. As pontes entre as células germinativas têm comportamento dinâmico e provavelmente atuam na determinação do ovócito entre as células do clone formado pelas mitoses pré meióticas formando posteriormente uma via de transporte para que os produtos sintetizados pelas células nutridoras atinjam o ovócito durante sua maturação. Os elementos do citoesqueleto presentes nas pontes intercelulares das gônadas das abelhas são basicamente microfilamentos e microtúbulos, mas nas pontes entre os cistócitos pré-meióticos outro tipo de filamento (espesso de natureza não definida, associado a elementos do retículo endoplasmático) está presente, atravessando a ponte e prendendo-se através dos microfilamentos à membrana plasmática. Estes filamentos aparentemente controlam o vão da ponte. Terminada a fase de proliferação os cistócitos tomam a forma de uma roseta e um fusoma, formado pela convergência das pontes, aparece no centro desta. Nesta conformação os filamentos grossos não estão presentes. Nova mudança ocorre com a diferenciação do ovócito e das células nutridoras, com a reorientação de todas as pontes de maneira a canalizar o conteúdo das futuras células nutridoras para o ovócito.

Spontaneous germ cell death by apoptosis in epididymis of the adult bat Artibeus lituratus

Many factors can lead cells to apoptosis during the various stages of cell life. This study was undertaken to characterize germ cell death in the epididymis of the adult Artibeus lituratus by histochemical and immunohistochemical techniques using light microscopy and transmission electron microscopy. The results showed that cells with a nuclear phenotype and ultrastructural characteristics of chromatin compaction were common in apoptosis. The Apoptag test confirmed that the suspected cells were apoptotic. It is suggested that immature germ cells, when released from the germinative epithelium, may be directed towards the epididymis instead of being disposed of in the testicle. Furthermore, intact immature cells can leave the testicle in the initial phases of apoptosis and complete this phenomenon in the epididymis.

Germ Cell Dynamics during the Annual Reproductive Cycle of Dendropsophus minutus (Anura: Hylidae)

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

The effect of sodium chloride on the formation of W/O microemulsions in soy bean oil/surfactant/water systems and the solubilization of small hydrophilic molecules

Partial pseudoternary phase diagrams were constructed for soy bean oil (SBO)/surfactant/NaCl aqueous solution systems, at 25 degrees C, using the anionic sodium bis(2-ethylhexyl) sulfosuccinate (ACT) and zwiterionic phosphatidylcholine (PC) or mixtures of these surfactants. The isotropic single phase of water-in-oil (W/O) microemulsions (MEs) is shown in the phase diagram and their viscosity reported. ME samples containing small amount of surfactant exhibit slightly higher viscosity than pure SBO, and were used in the solubilization of small water soluble molecules. NaCl enhances the area of the ME phase and MEs with different surfactant composition exhibit different induction time as obtained from tests of oxidative stability, and so are the MEs enriched with ascorbic acid, folic acid and FeSO4, with the latter exhibiting lower stability. The so prepared enriched soy bean oil has potential application in food industry since the surfactants are food grade. (C) 2007 Elsevier B.V. All rights reserved.

Effect of estrogen therapy, soy isoflavones, and the combination therapy on the submandibular gland of ovariectomized rats

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

Effect of broiler chicken age on ileal digestibility of corn germ meal

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efficacy and safety of a soy isoflavone extract in postmenopausal women: A randomized, double-blind, and placebo-controlled study

Objective: To investigate the efficacy of soy isoflavone on climacteric symptoms in postmenopausal women.Design: In this double-blind, randomized, placebo-controlled study, a total of 80 women (mean age =55.1 years), who reported 5 or more hot flush episodes per day, were randomized to receive either 250 mg of standardized soy extract (Glycine max AT) a total of 100 mg/day of isoflavone (n=40) or placebo (n=40). Exclusion criteria included: contra-indication for hormone therapy (HT), chronic gastrointestinal diseases, and users of HT within the preceding 6-months. For 10-months, climacteric symptoms were evaluated using a score card and the menopausal Kupperman index. Compliance and safety were also assessed. At baseline and the end of the study, lipid and hormonal profiles, as well as vaginal, mammographic and ultrasonographic parameters were measured. The t-test, Wilcoxon test and ANOVA were used in the statistical analysis.Results: At baseline, the mean number of hot flushes was 9.6 +/- 3.9 per day in the isoflavone group and 10.1 +/- 4.9 in the placebo group (p>0.05). After 10 months, there was a significant reduction in frequency of hot flushes among isoflavone users when compared to those on placebo (3.1 +/- 2.3 and 5.9 +/- 4.3, respectively) (p<0.001). Kupperman index mean values showed a significant reduction in both groups. However, soy isoflavone was significantly superior to placebo, in reducing hot flush severity (69.9% and 33.7%, respectively) (p<0.001). Endometrial thickness, mammography, vaginal cytology, lipids and hormonal profile did not change in both groups. No serious adverse event related to isoflavone treatment was reported.Conclusions: the soy isoflavone extract exerted favorable effects on vasomotor symptoms and good compliance, providing a safe and effective alternative therapeutic for postmenopausal women. (C) 2007 Elsevier B.V.. All rights reserved.

Histologic alterations of the submandibular glands and testicles induced by soy and zinc deficient diets

The purpose of this study was to examine in rats the histologic alterations of the submandibular glands and testicles induced by soy diets and zinc deficients diet. The zinc deficiency produced testicles alterations including seminiferous tubulus atrophy, germinative epithelium degeneration, spermatogenesis alterations and a significant atrophy of the submandibular glands which presented no much delimitated acines. The soy diet without complementations also compromised the spermatogenesis by showing seminiferous tubulus atrophied and a reduction of the germinative epithelium. The soy diet complemented by saline and vitaminic mixtures didn't produced testicles alterations but its induced in the submandibular glands a hypertrophy of the ductal component mainly in relation to the granular component.