169,921 research outputs found
Hyaluronic acid synthesis by mural granulosa cells and cumulus cells in vitro is selectively stimulated by a factor produced by oocytes and by transforming growth factor-beta
No full textIn ovarian antral follicles cumulus cells (approximately 1,000/follicle) closely surround the oocyte, and mural granulosa cells (approximately 50,000/follicle) are distributed at the periphery. Previous work (Salustri, A., Yanagishita, M., and Hascall, V. C. (1990) Dev. Biol. 138, 26-32) showed that oocytes produce a factor(s) which stimulates hyaluronic acid (HA) synthesis by cumulus cells during expansion of the cumulus cell-oocyte complex. We now show that mural granulosa cells also respond in vitro to the oocyte factor(s) with greatly increased HA synthesis. As with cumulus cells, a factor(s) present in fetal calf serum is required to retain newly synthesized HA in the extracellular matrix. Unlike cumulus cells, follicle-stimulating hormone (FSH) is not required for maximal stimulation, in part because mural granulosa cells synthesize prostaglandin E2 which can substitute for FSH in promoting cumulus cell-oocyte complex expansion. Of several growth factors studied, only transforming growth factor-beta 1 (TGF-beta 1) stimulated HA synthesis in both cell types. However, the stimulation of HA synthesis by TGF-beta 1 was additive with that for the oocyte factor(s), and neutralizing antibodies to TGF-beta did not inhibit the response to the oocyte factor(s). The results indicate that the oocyte factor(s) and TGF-beta 1 are not the same and that they operate through different receptors in stimulating HA synthesis. Epidermal growth factor was able to replace FSH in amplifying the response of cumulus cells to the oocyte factor(s) and in stimulating synthesis of dermatan sulfate proteoglycans
La fine del movimento del ’77. Bologna punto e a capo?
No full textil contributo analizza la vicenda del convegno che si tenne a Bologna nel 1977 e che segnò una cesura all'interno del movimento studentesco
Agents Complexing Copper as a Therapeutic Strategy for the Treatment of Alzheimer's Disease
No full textThe notion that a copper dysfunction is implicated in Alzheimer's disease (AD) is based on a number of observations from in vitro and clinical studies, as well as animal models. However, there is still significant controversy over whether it is an excess or a deficiency of copper to be involved in the pathogenesis of AD. Numerous studies support the hypothesis that an excess of copper contributes to AD, but experimental evidence in transgenic mouse models seems to suggest the contrary, and at least one clinical study shows that cognitive decline correlates positively with low copper levels. We have recently reported on a deregulation of the ceruloplasmin-copper relationship, specific to AD patients, consisting of an elevation of the copper pool not bound to ceruloplasmin, i.e. 'free' copper. This phenomenon could provide an explanation of the contrasting results obtained in clinical studies. Several clinical trials have been attempted in search of an anti-metal effect counteracting AD progression. Some of them have delivered encouraging results indicating that "metal protein attenuating compounds" can indeed alter positively the progression of the disease. This review summarizes these clinical studies and provides an overview of those in progress and in preparation
Fetal magnetocardiographic signals extracted by 'signal subspace' blind source separation.
No full textIn this paper, we apply independent component analysis to fetal magnetocardiographic data. In particular, we propose an extension of the "cumulant-based iterative inversion" algorithm to include a two-step "signal subspace" subdivision, which allows the user to control the number of components to be estimated by analyzing the eigenvalues distribution in an interactive way. Our results show that this method is a powerful means not only for the extraction of the cardiac signals from the background noise but also for a sharp separation of the baby's heart from the mother's
Coding sequence of a hyaluronan synthase homologue expressed during expansion of the mouse cumulus-oocyte complex
No full textMaturation of mammalian cumulus cell-oocyte complex in the preovulatory follicle involves the deposition of a hyaluronan-rich extracellular matrix by the cumulus cells. In this study, we report the complete coding sequence of a novel mouse hyaluronan synthase homologue expressed in cumulus cell-oocyte complexes induced to expand in vivo. The time frame of mRNA expression of this molecule correlates well with previous biochemical and immunohistochemical findings on the initiation of hyaluronan synthesis in maturing preovulatory follicles. Evolutionary comparison of the vertebrate hyaluronan synthase homologues indicates that there are at least two genes that code for these proteins
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