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91.
Momcilovic D Archbald LF Walters A Tran T Kelbert D Risco C Thatcher WW 《Theriogenology》1998,50(7):1131-1139
The objective of this study was to determine the reproductive performance of lactating dairy cows treated with GnRH and/or PGF2a for synchronization of estrus and ovulation. Between Days 43 and 57 post partum, a total of 374 dairy cows was divided into 4 groups. Cows in Group 1 (n = 62) were treated with 25 mg, i.m. PGF2a on Days 43 and 57; cows in Group 2 (n = 65) were not treated at this time; cows in Group 3 (n = 118) were treated with 100 ug, i.m. GnRH on Day 50, 25 mg, i.m. PGF2a on Day 57, 100 ug, i.m. GnRH on Day 59, and time-inseminated 16 h later; cows in Group 4 (n = 129) were treated with 25 mg, i.m. PGF2a once on Day 57. Cows in Groups 1 and 4 were inseminated at an induced estrus within 7 d after the last PGF2a treatment, and cows in Group 2 were inseminated at a noninduced estrus within a corresponding period of time. Conception rate, estrus detection rate and pregnancy rate were analyzed using logistic regression, and controlled for lactation number, body condition score and time of year. Days from calving to conception were analyzed using the GLM procedures of SAS, and the model included group, body condition score, lactation number, time of year, and their interactions. Cows in Group 3 had a significantly higher pregnancy rate than cows in Groups 1, 2 and 4. Orthogonal contrasts of mean days from calving to conception showed that cows in Group 3 had significantly (P < 0.01) less days from calving to conception than cows in Group 1 and Group 4. There was a significant effect of time of year on pregnancy rate and days from calving to conception, but there was no interaction between time of year and these reproductive characteristics. There was no effect of body condition score and lactation number on the reproductive characteristics evaluated. From the results of this study, it was concluded that better reproductive performance was observed in cows inseminated at a synchronized ovulation than in those inseminated at a synchronized estrous period. 相似文献
92.
Walters T. J.; Ryan K. L.; Tehrany M. R.; Jones M. B.; Paulus L. A.; Mason P. A. 《Journal of applied physiology》1998,84(4):1269-1277
We havepreviously documented the regional distribution of 70-kDa heat shockprotein (HSP70) in brains of rats made hyperthermic by brief exposureto high-powered microwaves (HPM; 2.06 GHz). We now compare HSP70expression induced by HPM exposure to that induced by exertionaland/or environmental heat stress. Rats were chronicallyimplanted with a temperature probe guide in the hypothalamic region ofthe brain (Tbr). After recovery,the following treatment groups were examined: HPM; sham exposed;treadmill exercise at room temperature (24°C; Ex-1); treadmillexercise in a warm environment (34°C; Ex-2); and sedentary groups(Sed-1 and Sed-2), in which ambient temperature was adjusted so thatthe Tbr mimicked the Tbr in the corresponding exercisegroups. Significant HSP70 expression occurred only in the hyperthermic(Ex-2, Sed-2, and HPM) groups. The pattern of HSP70 expression wassimilar among Ex-2 and Sed-2 rats but differed from that in HPM rats.We conclude that 1) the pattern ofHSP70 expression differs between HPM and nonmicrowave heating, and2) exercise alone was not sufficientto induce central HSP70 expression. 相似文献
93.
A. Stenyakina L.J. Walters E.A. Hoffman C. Calestani 《Molecular reproduction and development》2010,77(3):222-230
We studied the reproductive biology of Mytella charruana to determine the potential reproductive success of this newly introduced bivalve species from Central/South America. We analyzed gonad morphology, gametogenesis, and the sex ratios of introduced populations throughout a 12 month period. In the non‐native habitat M. charruana shows the same strategy of gametogenesis that had been observed in its native environment, which is an opportunistic type of gonadal cycle with gametes produced throughout the year. Instead, the spawning period of M. charruana along the southeastern US coast is extended compared to that found in the native environment. We determined the minimum size (shell length) of sexually reproductive mussels to be 1.25 cm. Interestingly, throughout the year the population samples were typically composed of a higher proportion of females. The female to male sex ratio varied within a wide range from 1:0 to 1:3.3. Upon this discovery we tested the effects of food availability on the gametogenesis of adult animals. The sex ratio of mussels collected from different locations and maintained in the laboratory with or without food changed toward a male‐bias under starvation conditions within a month. This is the first study directly showing that food availability can trigger sex reversal in an adult bivalve. According to our data this mussel species will likely continue to spread along the east coast of the US. Moreover, M. charruana may prove to be a model organism in the study of alternative sexuality in bivalves. Mol. Reprod. Dev. 77: 222–230, 2010. © 2009 Wiley‐Liss, Inc. 相似文献
94.
James E. Squires Pranavkumar Shivakumar Reena Mourya Kazuhiko Bessho Stephanie Walters Jorge A. Bezerra 《PloS one》2015,10(5)
ConclusionsLower inoculation of RRV-induced progressive liver injury and fibrosis via NK cells. These findings point to the potential use of NK cell-depleting strategies to block progression of liver disease in biliary atresia. 相似文献
95.
Airway basal cells (BC) function as stem/progenitor cells capable of differentiating into the luminal ciliated and secretory cells to replenish the airway epithelium during physiological turnover and repair. The objective of this study was to define the role of Notch signaling in regulating human airway BC differentiation into a pseudostratified mucociliated epithelium. Notch inhibition with γ-secretase inhibitors demonstrated Notch activation is essential for BC differentiation into secretory and ciliated cells, but more so for the secretory lineage. Sustained cell autonomous ligand independent Notch activation via lentivirus expression of the intracellular domain of each Notch receptor (NICD1-4) demonstrated that the NOTCH2 and 4 pathways have little effect on BC differentiation into secretory and ciliated cells, while activation of the NOTCH1 or 3 pathways has a major influence, with persistent expression of NICD1 or 3 resulting in a skewing toward secretory cell differentiation with a parallel decrease in ciliated cell differentiation. These observations provide insights into the control of the balance of BC differentiation into the secretory vs ciliated cell lineage, a balance that is critical for maintaining the normal function of the airway epithelium in barrier defense against the inhaled environment. 相似文献
96.
Sally A. Entrekin Kelly O. Maloney Katherine E. Kapo Annika W. Walters Michelle A. Evans-White Kenneth M. Klemow 《PloS one》2015,10(9)
Multiple stressors threaten stream physical and biological quality, including elevated nutrients and other contaminants, riparian and in-stream habitat degradation and altered natural flow regime. Unconventional oil and gas (UOG) development is one emerging stressor that spans the U.S. UOG development could alter stream sedimentation, riparian extent and composition, in-stream flow, and water quality. We developed indices to describe the watershed sensitivity and exposure to natural and anthropogenic disturbances and computed a vulnerability index from these two scores across stream catchments in six productive shale plays. We predicted that catchment vulnerability scores would vary across plays due to climatic, geologic and anthropogenic differences. Across-shale averages supported this prediction revealing differences in catchment sensitivity, exposure, and vulnerability scores that resulted from different natural and anthropogenic environmental conditions. For example, semi-arid Western shale play catchments (Mowry, Hilliard, and Bakken) tended to be more sensitive to stressors due to low annual average precipitation and extensive grassland. Catchments in the Barnett and Marcellus-Utica were naturally sensitive from more erosive soils and steeper catchment slopes, but these catchments also experienced areas with greater UOG densities and urbanization. Our analysis suggested Fayetteville and Barnett catchments were vulnerable due to existing anthropogenic exposure. However, all shale plays had catchments that spanned a wide vulnerability gradient. Our results identify vulnerable catchments that can help prioritize stream protection and monitoring efforts. Resource managers can also use these findings to guide local development activities to help reduce possible environmental effects. 相似文献
97.
The identification of a series of novel, soluble non-peptidic neuropeptide Y Y2 receptor antagonists
Lunniss GE Barnes AA Barton N Biagetti M Bianchi F Blowers SM Caberlotto LL Emmons A Holmes IP Montanari D Norris R Puckey GV Walters DJ Watson SP Willis J 《Bioorganic & medicinal chemistry letters》2010,20(24):7341-7344
The identification and subsequent optimisation of a selective non-peptidic NPY Y2 antagonist series is described. This led to the development of amine 2, a selective, soluble NPY Y2 receptor antagonist with enhanced CNS exposure. 相似文献
98.
99.
Senes A Chadi DC Law PB Walters RF Nanda V Degrado WF 《Journal of molecular biology》2007,366(2):436-448
We have developed an empirical residue-based potential (E(z) potential) for protein insertion in lipid membranes. Propensities for occurrence as a function of depth in the bilayer were calculated for the individual amino acid types from their distribution in known structures of helical membrane proteins. The propensities were then fit to continuous curves and converted to a potential using a reverse-Boltzman relationship. The E(z) potential demonstrated a good correlation with experimental data such as amino acid transfer free energy scales (water to membrane center and water to interface), and it incorporates transmembrane helices of varying composition in the membrane with trends similar to those obtained with translocon-mediated insertion experiments. The potential has a variety of applications in the analysis of natural membrane proteins as well as in the design of new ones. It can help in calculating the propensity of single helices to insert in the bilayer and estimate their tilt angle with respect to the bilayer normal. It can be utilized to discriminate amphiphilic helices that assume a parallel orientation at the membrane interface, such as those of membrane-active peptides. In membrane protein design applications, the potential allows an environment-dependent selection of amino acid identities. 相似文献
100.