86,585 research outputs found
The use of satellite data to calibrate a hydrodynamic model of the Venice Lagoon
No full textThe use of satellite data to calibrate a hydrodynamic model of the Venice Lagoon was discussed. Three couples of Landsat data was processed to retrieve the surface water temperature of the lagoon. A two-dimensional (2D) finite elements hydrodynamic model was developed to stimulate the tidal level within the lagoon considering all the variables related to morphological and astronomical factors
Evaluation of Suspended Particulate Matter for the Venice Lagoon Waters, by Using LANDSAT 7 ETM+ Data
No full textMOLECULAR DETERMINANTS OF MAMMALIAN FERTILITY: ROLE OF PROGESTERONE RECEPTOR MEMBRANE COMPONENT 1 (PGRMC1)
No full textReproductive efficiency in dairy cows is decreasing worldwide. The root cause of the declining fertility is probably a combination of a variety of physiological and management factors that have an additive effect on reproductive efficiency. These factors include increasing in milk production and herd size, greater use of confinement housing, labor shortages and higher inbreeding percentages. In addition, the reproductive physiology of dairy cattle has also changed in response to genetic selection for milk production. Compared with traditional dairy cows, modern dairy cows have longer intervals to first ovulation, a higher incidence of anestrus and abnormal luteal phases, lower blood progesterone and IGF-I concentrations, higher incidence of multiple ovulations and twinning rates as well as greater embryonic loss. Declining fertility represents an obstacle in maintaining profitability of dairy farms. It has been estimated that a slight increase in pregnancy rates results in a significant increase in profitability that could make the difference in whether a family farm remains in operation. These findings suggest that defining the factors and mechanisms that contribute to oocyte and embryo quality is essential for improving female fertility. In particular, basic knowledge of which proteins within the oocyte regulate meiosis, oocyte fertilizability and developmental potential would be advantageous.
Starting from these observations, our studies were conducted to test the hypothesis that PGRMC1 is one of the key factors that regulate mammalian oocyte quality and therefore female fertility. Initial indications that PGRMC1 participates in progesterone signaling in the reproductive system come from studies in which PGRMC1 expression was silenced using siRNA in ovarian cells. These experiments demonstrated that Progesterone’s ability to inhibit ovarian cells from undergoing apoptosis in vitro is dependent on PGRMC1, indicating that PGRMC1 plays an essential role in promoting the survival of ovarian cell in vitro. This led us to start our investigations on the function of PGRMC1 in bovine fertility.
Initial experiments were conducted to determine the presence and localization of PGRMC1 in various compartments of the bovine female reproductive organs, during the follicular and luteal phases of the estrous cycle. Importantly, these studies revealed the presence of PGRMC1 in the nucleus of bovine oocytes. Further studies revealed that PGRMC1 is present in both GV- and MII-stage oocyte, is associated with male and female pronuclei in the zygote and is highly expressed in the blastocysts, with typical localization at each of these stages.
Since fertilization and embryonic development are mainly dependent on the completion of oocyte maturation, we focused our attention on PGRMC1’s role during this important step. Our localization as well as our functional data suggest an important role of PGRMC1 in oocyte maturation that may be specifically related to the mechanism by which chromosomes segregate and the first polar body extruded. Moreover, we have started to elucidate the mechanism by which PGRMC1 could act as a regulator of oocyte meiosis. In fact we demonstrated not only that PGRMC1 co-localize with the active form of AURKB, but also that the activities of these two molecules may be somehow related. In fact, inhibition of AURKB causes changes in the localization of PGRMC1 and alterations in the MII chromosomal plate. Furthermore, our data suggest that alteration in the localization of PGRMC1 and AURKB could account in part for the increased aneuploidy and low development competence of oocytes of ovaries isolated from cows with reduced ovarian reserve.
In conclusion, the present study raise important questions regarding the role of PGRMC1 in the regulation of oocyte maturation and the loss of fertility of dairy cows. Despite the mechanism through which PGRMC1 regulates these processes is still unknown and remains to be deeply investigated, our data indicate that functional alterations of PGRMC1 could impair meiosis and reduce development competence of oocytes. Finally, understanding these mechanisms in cattle could provide insight into how these processes are regulated in other species, including humans
Tecniche di rivolgimento del podalico : le conoscenze delle donne coinvolte
No full textBackground
The breech presentation of the fetus inside the uterus is a situation in which the lower extremity of the fetus’s body is pointed downwards, and it occurs in 3-4% of pregnancies. If the breech presentation persists until the end of the pregnancy, the most indicated delivery procedure is the cesarean section. However, there are different methods and techniques to promote the cephalic version of the breech, that can be employed in different periods of the pregnancy to avoid the cesarean section procedure with the objective of a natural delivery.
Aim
The objective of this study is to primarily determine the amount of knowledge of women regarding the techniques that promote an inversion of the breech presentation and secondarily to pinpoint the sources of information of these women.
Methods
This research took place from July to August 2018 and consisted in the distribution of anonymous questionnaires to women who accessed the ward “Gravidanza a termine” of the foundation “IRCCS Cá Granda” of the clinic “Ospedale Maggiore Policlinico di Milano”. The participants of this study were 20 women who still presented a breech fetus at term of pregnancy.
Results
16 over 20 women knew at least one method for the cephalic version of a breech presentation. Half of these women, 8 over 16, came by this knowledge navigating the internet for personal interest. 6 women received information regarding these techniques through a trusted doctor, 1 woman through a trusted midwife and 1 woman through friends/family members. Furthermore, all women who participated showed interest in knowing more information regarding the existing techniques of cephalic version.
Conslusions
From the results of this research it emerges that the knowledge of women regarding the methods and techniques of a cephalic version is weak and lacks in-depth information; it is also clear that the main source of information of these women is not a midwife or a doctor, but more often the Internet itself. In conclusion, the solution to increase the knowledge of women regarding the existing techniques, could be to enable the midwife to provide information to women at the right time and with suitable materia
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Oxidative stress may impair oocyte quality in dairy cows of reproductive age with a reduced antral follicle count
No full textIn dairy cattle, oocytes isolated from ovaries with a reduced antral follicle count (AFC) have a low embryonic developmental competence. This may be related to oxidative stress, as indicated by our recent finding that ovaries with reduced AFC show a defective endothelial nitric oxide synthase/nitric oxide system. To further test this hypothesis, we evaluated whether the poor developmental competence of these oocytes was possibly due 1) to an imbalance of the reduced glutathione (GSH) system, because GSH is the major antioxidant compound stored within the oocyte and protects the zygote and early embryos from oxidative damage, and 2) to reduced mitochondrial activity. Ovaries were obtained from the abattoir, and oocytes were collected from ovaries with reduced AFC, with fewer than 10 follicles of 2 to 6 mm in diameter, and aged-matched controls, with more than 10 follicles of 2 to 6 mm in diameter. Oocyte GSH content was evaluated using the 5,5′-dithio-bis(2-nitrobenzoic acid)-GSH reductase recycling micro-GSH assay before and after in vitro maturation (IVM) in the presence or absence of 100 μM cysteamine, a GSH precursor. At the same time the developmental competence after IVF was assessed. Moreover, the mitochondrial activity during IVM was evaluated in additional oocytes from the two ovarian categories by specific MitoTracker dyes (MitoTracker FM Green and MitoTracker Orange CMTMRos, Invitrogen, Carlsbad, CA, USA) and subsequent image analysis (ImageJ software). All data were analysed by ANOVA followed by Fisher’s least significant differences test, and P-values <0.05 were considered significant. Experiments were repeated at least three times. Oocytes isolated from ovaries with a low AFC had a similar GSH content compared with oocytes isolated from control ovaries (n = 65 and 85, respectively; 4.31 ± 0.41 v. 4.51 ± 0.42 pmol oocyte–1). After IVM, oocytes from ovaries with reduced AFC showed a significantly lower GSH content compared with control oocytes (n = 55 and 65, respectively; 4.36 ± 0.31 v. 6.59 ± 0.39 pmol oocyte–1); however, cysteamine supplementation during IVM induced GSH accumulation similar to the control (n = 80 and 85, respectively; 9.88 ± 0.77 v. 10.45 ± 0.88 pmol oocyte–1). It is interesting that the increase in intracellular GSH content significantly improved the developmental competence of oocytes from ovaries with a reduced AFC (n = 196 and 201, respectively; 20.1 ± 2.9% v. 6.2 ± 1.6%), although the blastocyst rate remained lower than the control either with or without cysteamine (n = 218 and 212, respectively; 33.3 ± 3.8% and 34.2 ± 2.4%). Further, immature oocytes from ovaries with a low AFC showed a reduced mitochondrial membrane potential compared with control oocytes (n = 13 and 18, respectively; 1.74 ± 1.19 v. 2.22 ± 1.72, calculated as the ratio between the fluorescence of active and total mitochondria), whereas at the end of IVM, it declined in both categories at a comparable level (n = 17 and 24, respectively; 1.19 ± 0.10 and 1.30 ± 0.06). Our data confirmed the hypothesis that both the GSH imbalance and defective mitochondrial activity contribute to the limited developmental competence of oocytes from ovaries with a reduced AFC
Gap junction-mediated intercellular coupling controls chromatin remodeling during bovine oocyte growth and differentiation through cAMP-dependent mechanism(s)
No full textSynaptophysin and synaptobrevin 2 associate closely with packaging and storage of synaptic vesicles and transmitter release, and both play important roles in the development of rat cochlea. We examined the differential expression of synaptophysin and synaptobrevin 2 in the developing Sprague-Dawley rat cochlea, and investigated the relationship between their expression and auditory development. The expression of synaptophysin and synaptobrevin 2 was not observed in Kolliker's and Corti's organ at postnatal 1 day (P1) and P5, and the top turn of the cochlea at P10. Expression was detected in the outer spiral bundle (OSB), the inner spiral bundle (ISB), and the medial wall of the Deiters' cell of the cochlea at P14, and P28, and in the middle or the basal turn of Corti's organ at P10. Synaptobrevin 2 was expressed in the top of the inner hair cells (IHCs) in Corti's organ of both P14 and P28 rats. All spiral ganglion neurons (SGNs) were stained at all ages examined. The localization of synaptophysin and synaptobrevin 2 in the cochlea was closely associated with the distribution of nerve fibers and neural activity (the docking and release of synaptic vesicles). Synaptophysin and synaptobrevin 2 were expressed in a dynamic manner during the development of rat cochlea. Their expression differences during the development were in favor of the configuration course constructed between nerve endings and target cells. It also played a key role in the formation of the correct coding of auditory information during auditory system development
New insights on Flavescence dorée phytoplasma ecology in the vineyard agro-ecosystem in southern Switzerland
No full textPhytoplasmas associated with Flavescence dorée (FDp) grapevine disease are quarantine pathogens controlled through mandatory measures including the prompt eradication and destruction of diseased plants, and the insecticide treatments against the insect vector, the ampelophagous leafhopper Scaphoideus titanus. In the present study, a multidisciplinary approach has been applied to investigate the FDp ecological cycle in a test vineyard agro-ecosystem in Canton Ticino, south Switzerland. Despite the scarce population density of S. titanus, a regular trend of new infections (3.4% of the total vines) through the years was observed. The leafhopper Orientus ishidae was found as the most abundant among the captured insect species known as phytoplasma vectors (245 out of 315 specimens). The population of O. ishidae was evidenced prevalently (167 specimens) in the south-western side of the vineyard and within the neighbouring forest constituted mainly by hazel (Corylus avellana) and willow (Salix spp.). These plant species were found infected by FDp related strains (30% of analysed trees) for the first time in this study. Interestingly, O. ishidae was found to harbour FDp related strains in high percentage (26% of the analysed pools). In addition, 16SrV phytoplasma group was detected for the first time in the insect Hyalesthes obsoletus and a FDp related strain in Thamnotettix dilutior, present in low populations within the test vineyard. Molecular characterisation and phylogenetic analyses of methionine aminopeptidase (map) gene sequences of FDp and related strains, here identified, revealed the great prevalence of the map-type FD2 in grapevines (97%) and in O. ishidae pools (72%). Such a map-type was found also in hazel and in T. dilutior, but not in S. titanus. Moreover, map-types FD1 and FD3 were identified for the first time in Switzerland in several host plants and phytoplasma vectors, including grapevine (FD1), S. titanus (FD1) and O. ishidae (FD1 and FD3). Based on the data obtained in this study, it is reasonable to hypothesise that the ecological cycle of FDp could be related not exclusively to the grapevine-specific feeding diet of S. titanus, but it could include other insect vector(s) and/or plant host(s). Further studies will be needed to prove the role of O. ishidae as vector able to transmit FDp from wild plants (e.g. hazel) to grapevine
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