mTOR Controls Ovarian Follicle Growth by Regulating Granulosa Cell Proliferation

We have shown that inhibition of mTOR in granulosa cells and ovarian follicles results in compromised granulosa proliferation and reduced follicle growth. Further analysis here using spontaneously immortalized rat granulosa cells has revealed that mTOR pathway activity is enhanced during M-phase of the cell cycle. mTOR specific phosphorylation of p70S6 kinase and 4E-BP, and expression of Raptor are all enhanced during M-phase. The predominant effect of mTOR inhibition by the specific inhibitor Rapamycin (RAP) was a dose-responsive arrest in the G1 cell cycle stage. The fraction of granulosa cells that continued to divide in the presence of RAP exhibited a dose-dependent increase in aberrant mitotic figures known as anaphase bridges. Strikingly, estradiol consistently decreased the incidence of aberrant mitotic figures. In mice treated with RAP, the mitotic index was reduced compared to controls, and a similar increase in aberrant mitotic events was noted. RAP injected during a superovulation regime resulted in a dose-dependent reduction in the numbers of eggs ovulated. Implications for the real-time regulation of follicle growth and dominance, including the consequences of increased numbers of aneuploid granulosa cells, are discussed

The effects of mid-altitude on endocrine profile

Many of the physiologic changes that occur during acute and prolonged altitude exposure may actually negate adaptations that possibly improve physiologic performance upon return to sea level. Fourteen volunteer male students (male scouts) who inhabit at 1050 m were enrolled into the study to research; how mid-altitude affects some endocrine parameters. The basic evaluation was done before the camping at 3200 m, and the endocrine evaluation was repeated 10 days after, at the end of the camping. Volunteer students went through a general check up at the beginning. Blood samples were taken for determining the amount of growth hormone (GH), prolactine (PRL), follicule stimulating hormone (FSH), luteinizing hormone (LH), thyroid stimulating hormone (TSH), total triiodotyronine (TT3), total tyroxine (TT4), total testosterone (TTes) and cortisol levels. The levels of GH, PRL, FSH, LH, and TTes levels were changed after the camping period, and the difference found statistically significant (p<0.05). These observations suggest that exposure to altitude is associated with hyperprolactinemia and an impaired pituitary gonadal function. The alterations in the hormones levels are either be due to hypoxic stress or secondary to altitude induced hyperprolactinemia. The special characteristics of hypobaric hypoxia have been affected directly the endocrine profile

The effects of mid-altitude on endocrine profile

Many of the physiologic changes that occur during acute and prolonged altitude exposure may actually negate adaptations that possibly improve physiologic performance upon return to sea level. Fourteen volunteer male students (male scouts) who inhabit at 1050 m were enrolled into the study to research; how mid-altitude affects some endocrine parameters. The basic evaluation was done before the camping at 3200 m, and the endocrine evaluation was repeated 10 days after, at the end of the camping. Volunteer students went through a general check up at the beginning. Blood samples were taken for determining the amount of growth hormone (GH), prolactine (PRL), follicule stimulating hormone (FSH), luteinizing hormone (LH), thyroid stimulating hormone (TSH), total triiodotyronine (TT3), total tyroxine (TT4), total testosterone (TTes) and cortisol levels. The levels of GH, PRL, FSH, LH, and TTes levels were changed after the camping period, and the difference found statistically significant (p<0.05). These observations suggest that exposure to altitude is associated with hyperprolactinemia and an impaired pituitary gonadal function. The alterations in the hormones levels are either be due to hypoxic stress or secondary to altitude induced hyperprolactinemia. The special characteristics of hypobaric hypoxia have been affected directly the endocrine profile

The consequences of the Chernobyl accident: First results in the radioecology project of the French-German initiative

The French-German Initiative for Chernobyl, implemented by IPSN and GRS, includes a Project on the Radioecological Consequences of the Accident. Different fields of radioecology and post-accidental aspects had been chosen, such as radionuclides transfers to plants, to animals, by surface run-off, in the aquatic environment and in the urban environment, wastes management and countermeasures. Data from Belarus, Russia and Ukraine, have been collected, verified and organized. This constitutes a tool for development and validation of operational, assessment and explicative models. In the different part of ecosystems, the radionuclides transfers have been quantified and the main parameters influencing identified. For wastes, unified categorizations for the three countries have been adopted for wastes and for disposals. The operational database built allows the management of the wastes disposal sites. Countermeasures used after the accident for urban areas, natural and agricultural environment, have been described and classified. A methodology for evaluating their effectiveness has been developed. For linking the different data, maps of initial and present contamination by 137Cs and 90Sr have been drawn up and relevant environmental non radioactive data have been collected with all the others, structured in an unique database REDAC and georeferenced using a Geographical Information System

Ultrastructural and immunohistochemical similarities of two distinct entities; multiple sclerosis and hereditary motor sensory neuropathy

In the present study, we present the ultrastructural. and immunohistochemical. properties of the sural nerves of two patients, one of whom was diagnosed as having multiple sclerosis with involvement of the peripheral nervous system (PNS), and the other as having hereditary motor sensory neuropathy type-I with involvement of the central nervous system (CNS). Expression of several extracellutar matrix (ECM) proteins (fibronectin, laminin, and collagen type-IV), intermediate filaments (vimentin) and S-100 protein (marker for the axon-Schwann cell interface) was investigated by means of immunohistochemical. methods. In addition, the tissue samples were evaluated ultrastructurally. Immunohistochemical staining revealed increased expression of the ECM molecules mentioned above in relation with the sural. nerves of the patients. We hypothesize that this enhanced expression is due to Schwann cell-axon interactions. Vimentin expression was different in Schwann cells and S-100 immunostaining was decreased near the Schwann cell-axon interface. Myelin fragmentation, axon vacuolization, onion bulbs, tomoculous formation, axonal. degeneration were found to occur. These results suggest that there is active ECM reorganization in the sural nerve of these patients, and some ultrastructural changes are similar in the damaged axonal organization and in Schwann cells although the changes are not completely the same in the two patients. In conclusion, our study demonstrates that there is an association between the demyelinization process in the CNS and the PNS even though they are affected by different mechanisms. (C) 2004 Elsevier GmbH. All rights reserved