排序方式： 共有23条查询结果，搜索用时 109 毫秒
1.
E Breininger BE Vecchi Galenda GM Alvarez C Gutnisky PD Cetica 《Reproduction in domestic animals》2014,49(6):1068-1073
Oocyte maturation depends on the metabolic activity of cumulus–oocyte complex (COC) that performs nutritive and regulatory functions during this process. In this work, the enzymes [phosphofructokinase (PFK) and malate dehydrogenase (MDH)] were tested to elucidate the metabolic profile of porcine COCs during the in vitro maturation (IVM). Enzymatic activity was expressed in U/COC and U/mg protein (specific activity) as mean ± SEM. In vitro maturation was performed with 2‐oxoglutarate (5, 10 and 20 mm ) or hydroxymalonate (30, 60 and 100 mm ) inhibitors of PFK and MDH, respectively. The PFK and MDH activities (U) remained constant during maturation. For PFK, the U were (2.48 ± 0.23) 10?5 and (2.54 ± 0.32) 10?5, and for MDH, the U were (4.72 ± 0.42) 10?5 and (4.38 ± 0.25) 10?5 for immature and in vitro matured COCs, respectively. The specific activities were significantly lower after IVM, for PFK (4.29 ± 0.48) 10?3 and (0.94 ± 0.12) 10?3, and for MDH (9.08 ± 0.93) 10?3 and (1.89 ± 0.10) 10?3 for immature and in vitro matured COCs, respectively. In vitro maturation percentages and enzymatic activity diminished with 20 mm 2‐oxoglutarate or 60 mm hydroxymalonate (p < 0.05). Viability was not affected by any concentration of the inhibitors evaluated. The U remained unchanged during IVM; however, the increase in the total protein content per COC provoked a decrease in the specific activity of both enzymes. Phosphofructokinase and MDH necessary for oocyte IVM would be already present in the immature oocyte. The presence of inhibitors of these enzymes impairs the meiotic maturation. Therefore, the participation of these enzymes in the energy metabolism of the porcine oocyte during IVM is confirmed in this study. 相似文献
2.
The degree of piliation of 29 haemolytic and 4 non-haemolytic Australian strains of Moraxella bovis representing 7 different pilus antigen groups was determined. The infectivity and virulence for the eye was measured in steroid-treated mice and in cattle. Non-piliated strains failed to infect the murine eye. Most moderately or heavily piliated strains reproducibly produced the highest infectivity and virulence scores in mice when compared with lightly or very lightly piliated strains (p less than 0.05). Non-haemolytic, piliated strains were infective and in one instance virulent for mice. Almost similar levels of infectivity and virulence were observed for 7 representative haemolytic strains tested in both cattle and mice. The relative molecular weight of pilin sub-units was compared using sodium dodecyl-sulphate polyacrylamide gel electrophoresis. Three classes of pili, alpha, beta and gamma of ascending sub-unit size were identified among the 7 pilus antigen serogroups. Pilin sub-unit size bore no relationship to the degree of piliation but most strains that were highly virulent in mice and cattle expressed alpha and gamma sub-units. Some strains appeared capable of switching from alpha to beta or form beta to gamma sub-unit production. 相似文献
3.
JO Simcock SS Withers CY Prpich CA Kuntz BE Rutland 《Journal of the American Veterinary Medical Association》2012,241(5):608-614
Objective-To evaluate adverse effects and survival times in dogs with osteosarcoma that received a single SC infusion of carboplatin as adjunctive chemotherapeutic treatment following limb amputation or limb-sparing surgery. Design-Retrospective case series. Animals-17 client-owned dogs with spontaneously occurring osteosarcoma. Procedures-Medical records of dogs that underwent limb amputation or limb-sparing surgery followed by a single continuous SC infusion of carboplatin (total dose, 300 mg/m(2) infused over 3, 5, or 7 days) were evaluated. Signalment, tumor location, type of surgery (amputation or limb-sparing), duration of carboplatin infusion, results of hematologic and serum biochemical analyses, and adverse effects were recorded. Kaplan-Meier survival analysis was performed. Results-Median survival time for all dogs was 365 days. Nine dogs had adverse bone marrow-related (hematologic) effects, 1 had adverse gastrointestinal effects, and 7 had infections at the surgical site. No significant differences were detected in survival times of dogs grouped according to tumor location, type of surgery, duration of carboplatin infusion, or development of postoperative infection. Conclusions and Clinical Relevance-Median survival time and adverse effects in dogs with osteosarcoma that received a single SC infusion of carboplatin over a 3-, 5-, or 7-day period as adjunctive treatment following limb amputation or limb-sparing surgery were comparable to those of previously reported chemotherapy protocols requiring IV drug administration over several weeks. Further investigation is needed to evaluate the efficacy of this protocol as adjunctive treatment for osteosarcoma and other tumors in dogs. 相似文献
4.
Transition into higher education requires students to adjust to a new environment while showing greater independence in managing their own academic and personal life. This is often more difficult for international students who have to adjust to a different country, culture, and potentially another language. A cohort of first-year veterinary medicine students (17% international students) was investigated at a UK university using qualitative and quantitative questionnaires rating first-year experience and support services and statistical analysis of students' assessment performance. While the overall undergraduate perception was that they had learned a lot and progressed well, students in both groups struggled to cope with the workload. The non-UK educated students and students with English as a foreign language also struggled more with teaching delivery in lectures and participation in self-directed group learning and were more likely to feel that the veterinary degree program was too difficult. There was no statistical difference in how British and international students perceived the support system, although it was noticeable that the level of tutorial support was perceived as tutor-dependent. The international students particularly struggled with the assessments in early modules and also with the spot assessment method. However, in the practical assessments, using observed, structured practical exam stations, international and British students performed equally well. Increased support in the initial transition time, especially with regard to communication skills and confidence required for interactive teaching and learning environments such as small-group teaching, as well as increased time for specific assessment types, might benefit the needs of many international students. 相似文献
5.
NR Salvetti C Baravalle GA Mira EJ Gimeno BE Dallard F Rey HH Ortega 《Reproduction in domestic animals》2009,44(5):805-814
The purpose of this study was to estimate the expression and relative amounts of estrogen (ER) and progesterone receptors (PR) and their isoforms as well as heat shock protein 70 (HSP70) in ovaries of rats with induced cystic ovarian disease (COD). Primary, secondary, tertiary, atretic and cystic follicles were evaluated by immunohistochemistry and total ovarian proteins were analyzed by Western blot. In the granulosa layer, growing and cystic follicles in the treated group have a higher expression of ERα than growing follicles of control individuals. In the theca interna layer, tertiary follicles presented a significantly higher expression of ERα in the treated group. An increase in total ERα protein was detected in the treated group. Granulosa cells of all growing, atretic and cystic follicles show a lower expression of ERβ in animals with COD, and the total protein expression of ERβ was lower in this group. The expression of PR was lower in the granulosa cell layer of tertiary and cystic follicles in treated animals, and theca interna layer had less intense immunostaining in this group. Although there were no differences in the expression of PR-B by Western blotting, the expression of PR-A was higher and the expression of PR-C was smaller in the treated group. An intense HSP70 immunostaining was observed in the cells of cystic follicles. By Western blotting, higher protein expression of HSP70 was detected in the ovarian samples of the control group than those of the treated ones. Ovaries of animals with COD exhibited an altered steroid receptor expression and subtype balance as compared with control animals, and an increase in HSP70 immunoexpression. 相似文献
6.
Jennie N. Jeyapalan Victoria. James David S. Gardner Jennifer H. Lothion-Roy Nigel P. Mongan Catrin Sian Rutland 《Anatomia, histologia, embryologia》2023,52(1):93-100
Research is often an essential component of completing a veterinary medicine degree, with universities worldwide aiming to teach students a variety of techniques and general research comprehension and skills. As universities worldwide navigated the COVID-19 pandemic, it was often necessary to move towards distance learning, this was employed for the research module at The University of Nottingham, School of Veterinary Medicine and Science. Following completion of their independent research project, each student cohort was sent a student evaluation of the module questionnaire and quantitative and qualitative analysis was undertaken. In addition, assessment outcomes based on dissertation grade, supervisor grade and overall module score were analysed quantitatively. This was conducted on both the individual cohorts and between the pre- and peri-pandemic groups, ranging from 2017–2018 through to 2021–2022 cohorts. The students received increased dissertation and supervisor grades (by nearly 6%) during the 2021–2022 peri-pandemic cohort, when compared to the pre-pandemic cohorts, but did differ significantly compared to the 2020–2021 cohort. The pre- and peri-pandemic Likert-scale ratings for module organisation and assessment criteria were similar, workload management and the ability to explore concepts and ideas was reduced in the peri-pandemic cohorts, whereas the accessibility to resources was increased in the peri-pandemic students compared to those taught prior to the pandemic. Student feedback can provide essential information when designing and managing research projects and when compared to assessment grades it can help us understand attainment, essential information when providing a quality university level education whilst supporting student welfare following the COVID-19 pandemic. 相似文献
7.
The objective of this study was to investigate whether butylated hydroxytoluene (BHT) could be used as a suitable supporter or alternative of egg yolk during preservation of goat spermatozoa. Three in vitro experiments and a fertility test were conducted to evaluate the effect of BHT on viability of chilled‐stored semen as well as motility and kidding rate of frozen‐thawed spermatozoa. In the first two experiments, ejaculates (n = 30/experiment) were collected from 10 bucks, split, diluted with egg yolk‐based and egg yolk‐free extenders supplemented with or without 0.3, 0.6, 2, 5 and 8 mm BHT and stored at 5°C for 168 h. In the third experiment, 30 ejaculates were collected from the above‐mentioned bucks, split and diluted with egg yolk‐free extenders supplemented with or without 0.3, 0.6 and 0.9 mm BHT and egg yolk‐based extenders supplemented with or without 5 mm BHT. Diluted semen was cooled to 5°C over a period of 4 h, frozen and thawed in the form of 0.3‐ml pellets. In the fertility test, 75 ejaculates were collected from two proven fertile bucks, split, diluted with egg yolk‐free extenders containing 0.6 mm BHT and egg yolk‐based extenders supplemented with or without 5 mm BHT, frozen and thawed as described above. An insemination volume of 0.6 ml containing 120–140 × 106 progressively motile spermatozoa was used for a single cervical insemination of cloprostenol‐synchronized does (n = 230). The results showed that addition of 5 mm BHT to egg yolk‐deficient (2.5%) extenders significantly improved viability of chilled‐stored semen together with motility (48.5%) and fertility (62.5%) of frozen‐thawed spermatozoa. Replacement of egg yolk in semen extenders by 0.6 mm BHT could sustain not only viability of chilled‐stored semen but also post‐thaw motility (47.5%) and fertility (53.75%) of frozen‐thawed spermatozoa. In conclusion, supplementation of semen diluents with BHT can ameliorate preservability of goat sperm. 相似文献
8.
A "Schrodinger Cat" Superposition State of an Atom 总被引：1，自引：0，他引：1
A "Schrodinger cat"-like state of matter was generated at the single atom level. A trapped 9Be+ ion was laser-cooled to the zero-point energy and then prepared in a superposition of spatially separated coherent harmonic oscillator states. This state was created by application of a sequence of laser pulses, which entangles internal (electronic) and external (motional) states of the ion. The Schrodinger cat superposition was verified by detection of the quantum mechanical interference between the localized wave packets. This mesoscopic system may provide insight into the fuzzy boundary between the classical and quantum worlds by allowing controlled studies of quantum measurement and quantum decoherence. 相似文献
10.