Search

This study investigated the factors affecting circulating progesterone (P4) concentrations in cows with similar genetic merit for milk production traits, but with extremes of good (Fert+) or poor (Fert-) genetic merit for fertility traits. Study 1: 28 cows were enrolled in an ovulation synchronization protocol at 61 ± 13 (±standard deviation) days postpartum, and data are presented for 13 Fert+ and 9 Fert- cows that remained in the study. Progesterone concentrations were determined from d 0 to 9 (d 0 = estrus) and on d 7, corpus luteum (CL) volume and blood flow area (BFA) were measured by B-mode and Doppler ultrasonography, respectively. Cows were administered PGF2α on d 7 in the p.m. and d 8 in the a.m. to regress the CL, and 2 controlled internal drug release devices were inserted per vaginum on d 8 in the a.m. Liver biopsies were collected on d 9 and hepatic mRNA abundance of genes involved in P4 catabolism was determined. On d 10, the controlled internal drug release inserts were removed and frequent blood samples were collected to measure the rate of decline in circulating P4. The Fert+ cows tended to have greater dry matter intake compared with Fert- cows (+0.79 kg of dry matter/d), but similar milk production (29.82 kg/d). After synchronized ovulation, the rate of increase in circulating P4 concentrations was greater in Fert+ cows compared with Fert- cows. No effect of genotype on CL volume was detected, but BFA was 42% greater in Fert+ cows compared with Fert- cows. The Fert- cows had greater mRNA abundance of cytochrome P450, family 3, subfamily A (CYP3A) compared with Fert+ cows, but the mRNA abundance of aldo-keto reductase family 1, member C1 (AKR1C1), AKR1C3, AKR1C4, and cytochrome P450, family 2, subfamily C (CYP2C) were similar. The half-life and metabolic clearance rate of P4 were similar in Fert+ cows and Fert- cows. Study 2: 23 cows were enrolled in an ovulation synchronization protocol at 55 ± 7 (±standard deviation) d postpartum, and data are presented for 13 Fert+ and 8 Fert- cows that remained in the study. On d 4, 7, 10, and 13 (d 0 = estrus), CL volume and BFA were measured as in study 1. Progesterone concentrations were measured from d 1 to 13. Corpus luteum volume was 41% greater in Fert+ cows compared with Fert- cows but no effect of genotype on BFA was detected. Mean circulating P4 concentrations were 79% greater in Fert+ cows compared with Fert- cows. Milk yield was similar in both genotypes. The results indicate that greater circulating P4 concentrations were primarily due to greater CL P4 synthetic capacity rather than differences in P4 clearance in this lactating cow genetic model of fertility. [ABSTRACT FROM AUTHOR]

With the worldwide increase in diabetes prevalence there is a pressing unmet need for novel antidiabetic therapies. Insufficient insulin production due to impaired β-cell function and apoptotic reduction of β-cell mass is a common denominator in the pathogenesis of diabetes. Current treatments are directed at improving insulin sensitivity, and stimulating insulin secretion or replacing the hormone, but do not target progressive apoptotic β-cell loss. Here we review the current development of small-molecule inhibitors designed to rescue β-cells from apoptosis. Several distinct classes of small molecules have been identified that protect β-cells from inflammatory, oxidative and/or metabolically induced apoptosis. Although none of these have yet reached the clinic, β-cell protective small molecules alone or in combination with current therapies provide exciting opportunities for the development of novel treatments for diabetes. [ABSTRACT FROM AUTHOR]

Abstract: A finite element methodology for thermo-mechanical fatigue analysis of a subcritical power plant outlet header under realistic loading conditions is presented. The methodology consists of (i) a transient heat transfer model, (ii) a sequential anisothermal cyclic viscoplastic model and (iii) a multiaxial, critical-plane implementation of the Ostergren fatigue indicator parameter. The methodology permits identification of the local thermo-mechanical stress–strain response at critical locations and prediction of fatigue life and cracking orientation for complex transient, anisothermal, cyclic elastic–plastic-creep material behaviour. Measured plant data, in the form of steam and pipe temperature transients and steam pressure data, are employed to identify heat transfer constants and validate the predicted thermal response, with particular attention given to plant start-up and attemperation effects. The predictions indicate out-of-phase temperature-strain response at the header inside surface and in-phase response on the outside surface. Cooling transients are predicted to control damage and crack initiation at the inner bore, whereas heating transients are predicted to have a more damaging effect at weld locations. A representative test cycle is presented, which is shown to capture the salient thermo-mechanical cyclic damage of the realistic cycle. The predicted results correlate well with industrial experience in terms of crack (initiation) orientation, location and life. [Copyright &y& Elsevier]

This paper is concerned with the development of a methodology for thermomechanical analysis of high temperature, steam-pressurized P91 pipes in electrical power generation plant under realistic (measured) temperature and pressure cycles. In particular, these data encompass key thermal events, such as "load-following" temperature variations and sudden, significant fluctuations in steam temperatures associated with attemperation events and "trips" (sudden plant shut-down), likely to induce thermomechanical fatigue damage. An anisothermal elastic-plastic-creep material model for cyclic behavior of P91 is employed in the transient finite element (FE) model to predict the stress-strain-temperature cycles and the associated strain-rates. The results permit characterization of the behavior of pressurized P91 pipes for identification of the thermomechanical loading histories relevant to such components, for realistic, customized testing. This type of capability is relevant to design and analysis with respect to the evolving nature of power plant operating cycles, e.g., associated with more flexible operation of fossil fuel plant. [ABSTRACT FROM AUTHOR]

Matrix remodeling, degradation, inflammation and invasion liberate peptide fragments that can subsequently interact with cells in an attachment-independent manner. Such ‘soluble’ matrix components, including collagens, fibronectin and laminin, induced Smad activation (termed crosstalk signaling), which follows a similar chronological sequence and R-Smad specificity as induced by transforming growth factor (TGF)-β1. Smad4 nuclear translocation occurred in response to collagen binding, indicating downstream signal propagation. TGF-β scavenging antibody affected only TGF-β1, but not crosstalk-induced responses. TGF-β type II receptor mutation (DR26Δ25), which is deficient in TGF-β type I receptor recruitment to the ligand, induced a heterotetramer signaling complex, and propagated Smad2 activation only through collagen induction and not TGF-β signaling. Consequentially, TGF-β ligand participation is not required for crosstalk signaling. This signaling requires a functional integrin β1 receptor as showed by RNA interference. Co-immunoprecipitation (co-IP) and fluorescent microscopy indicate the involvement of focal adhesion kinase (FAK) and Src activity in collagen-induced signal propagation, and suggest a membrane signaling complex formation that includes both TGF-β receptors and integrins. The related gene expressional responses are distinct from that evoked by TGF-β1, supporting its separate function. This signaling mechanism expands and partially explains TGF-β receptor dynamics and consequential signaling diversity-related gene expressional plasticity. [ABSTRACT FROM AUTHOR]

Significant developments in minimally invasive surgery (MIS) for the adult population have led to increased application of MIS techniques for pediatric patients.Laparoscopy is the most common mis procedure used in pediatrics. Traditional surgical procedures that are now being performed laparoscopically include gastrostomy, pyloromyotomy, and repair of congenital diaphragmatic hernia and imperforate anus.All perioperative team members must be prepared to provide appropriately sized instruments and equipment to facilitate use of MIS techniques in the pediatric population and must ensure safe patient care to achieve optimal patient outcomes. [ABSTRACT FROM AUTHOR]

Calcific myonecrosis is a rare and latent condition characterized by a dystrophic calcified lesion that can present 10-64 years following initial trauma. Of the 25 cases documented in English world literature, all have occurred in the lower extremity exclusively. We report a case of a 60-year-old man with a painless enlarging left forearm mass that was subsequently diagnosed as calcific myonecrosis. Awareness of this lesion arising outside of the lower extremity is important to avoid unnecessary surgical intervention and patient reassurance. [ABSTRACT FROM AUTHOR]