Myosin Transformation In Thyrotoxic Rat Soleus Muscle

Male Sprague-Dawley rats were injected with 300{dollar}\mu{dollar}g/kg body weight of Triiodo-L-thyronine (T{dollar}\sb3{dollar}) and L-thyroxine (T{dollar}\sb4{dollar}) on alternate days over a 28-day treatment period. Thyrotoxicosis was confirmed by increased serum T{dollar}\sb3{dollar} levels and a pronounced ventricular hypertrophy (p {dollar}\le{dollar} 0.05 after 5 days). The effects of thyroid hormone on isometric contractile properties of the slow-twitch soleus muscle were studied in situ after 2, 5, 7, 15, 21 or 28 days. Time to peak tension (TPT) and one half relaxation time (1/2 RT) were significantly reduced after 5 days (T-5, p {dollar}\le{dollar} 0.05) and reached 56.7% and 51.1% of age-matched control values at T-28. This abbreviated twitch response increased the fusion required for the summation, and force production at sub-maximal stimulation frequencies was reduced.;The Ca{dollar}\sp{lcub}2+{rcub}{dollar}-activated myosin ATPase activity of experimental muscles assayed at pH 9.8 increased to 400% of control activity at T-28. A further indication of myosin transformation was a decrease in the complement of slow myosin light chains (MLC1{dollar}\sb{lcub}\rm s{rcub}{dollar} and 2{dollar}\sb{lcub}\rm s{rcub}{dollar}) and a concomitant increase in fast myosin light chains (MLC1{dollar}\sb{lcub}\rm f{rcub}{dollar}, 2{dollar}\sb{lcub}\rm f{rcub}{dollar} and 3{dollar}\sb{lcub}\rm f{rcub}{dollar}) (p {dollar}\le{dollar} 0.05 at T-15).;Myosin heavy chain (MHC) composition was analyzed with four monooclonal antibodies (Mabs) which were screened for their specificity to rat MHC isoforms. Immunoblot and ELISA analyses demonstrated a reduction of type I (slow) MHC in experimental muscles (p {dollar}\le{dollar} 0.05 at T-5). The embryonic MHC was not re-expressed. A novel MHC isoform (IIB/IIX) appeared by T-5. Immunofingerprinting experiments suggested that this was the IIB rather than the IIX MHC isoform.;Enzyme histochemistry and immunocytochemistry were used to assess whether MHC transformation was uniform or fibre-specific. Type I MHC was reduced in all type I fibres but was never completely eliminated. The number of fibres expressing type II MHC increased to reach 90.3 {dollar}\pm{dollar} 1.6% at T-28 but a sub-population of fibres (10%) remained unaffected. De novo expression of IIB MHC occurred initially in pre-existing IIA fibres, and was still restricted to 31.4 {dollar}\pm{dollar} 4.4% of the fibre population at T-28.;This study demonstrated that changes in MHC composition occurred rapidly but were probably of insufficient magnitude to account for the initial changes in contractile function. The differential response of individual fibres to thyroid hormone may result from a compromised neuromuscular interaction, or may stem from their developmental origin which could limit their adaptive range

Experimental investigation of water, snow and granular ice effects on ice failure processes and impact loads

A large series of laboratory ice crushing experiments was performed to investigate the effects of external boundary condition and indenter contact geometry on ice load magnitude under crushing conditions. Four boundary conditions were considered: dry cases, submerged cases, and cases with the presence of snow and granular ice material on the indenter surface. Indenter geometries were a flat plate, wedge shaped indenter, (reverse) conical indenter, and spherical indenter. These were impacted with artificially produced ice specimens of conical shape with 20° and 30° cone angles. All indenter – ice combinations were tested in dry and submerged environments at 1 mm/s and 100 mm/s indentation rates. Additional tests with the flat indentation plate were conducted at 10 mm/s impact velocity and a subset of scenarios with snow and granular ice material was evaluated. The tests were performed using a material testing system (MTS) machine located inside a cold room at an ambient temperature of - 7°C. Data acquisition comprised time, vertical force, and displacement. In several tests with the flat plate and wedge shaped indenter, supplementary information on local pressure patterns and contact area were obtained using tactile pressure sensors. All tests were recorded with a high speed video camera and still photos were taken before and after each test. Thin sections were taken of some specimens as well. Ice loads were found to strongly depend on contact condition, interrelated with pre-existing confinement and indentation rate. Submergence yielded higher forces, especially at the high indentation rate. This was very evident for the flat indentation plate and spherical indenter, and with restrictions for the wedge shaped indenter. No indication was found for the conical indenter. For the conical indenter it was concluded that the structural restriction due to the indenter geometry was dominating. The working surface for the water to act was not sufficient to influence the failure processes and associated ice loads. The presence of snow and granular ice significantly increased the forces at the low indentation rate (with the flat indentation plate) that were higher compared to submerged cases and far above the dry contact condition. Contact area measurements revealed a correlation of higher forces with a concurrent increase in actual contact area that depended on the respective boundary condition. In submergence, ice debris constitution was changed; ice extrusion, as well as crack development and propagation were impeded. Snow and granular ice seemed to provide additional material sources for establishing larger contact areas. The dry contact condition generally had the smallest real contact area, as well as the lowest forces. The comparison of nominal and measured contact areas revealed distinct deviations. The incorporation of those differences in contact process pressures-area relationships indicated that the overall process pressure was not substantially affected by the increased loads

Learning Communities: A Business School Perspective

This paper discusses the organization and operation of a university learning community program at the University of North Carolina at Greensboro (UNCG). After several years, the program administrator and certain of the faculty and staff reflected on the achievements of the program. The learning community concept is discussed as well as the nature of the learning activities both general and those specific to the business school. The program reported higher levels of student retention and students reported higher involvement in leadership skill development and the UNCG community than students who were not in the learning community program

Increased APOBEC3G and APOBEC3F expression is associated with low viral load and prolonged survival in simian immunodeficiency virus infected rhesus monkeys

<p>Abstract</p> <p>Background</p> <p>The cytidine deaminases APOBEC3G (A3G) and APOBEC3F (A3F) are innate cellular factors that inhibit replication of a number of viruses, including HIV-1. Since antiviral activity of APOBEC3 has been mainly confirmed by <it>in vitro </it>data, we examined their role for disease progression in the SIV/macaque model for AIDS.</p> <p>Results</p> <p>We quantified A3G and A3F mRNA in PBMC and leukocyte subsets of uninfected and SIVmac-infected rhesus macaques. Compared with uninfected animals, we found increased A3G and A3F mRNA levels in PBMC, purified CD4+ T-cells and CD14+ monocytes as well as lymph node cells from asymptomatic SIV-infected macaques. APOBEC3 mRNA levels correlated negatively with plasma viral load, and highest amounts of APOBEC3 mRNA were detected in long term non-progressors (LTNPs). During acute viremia, A3G mRNA increased in parallel with MxA, a prototype interferon-stimulated gene indicating a common regulation by the initial interferon response. This association disappeared during the asymptomatic stage.</p> <p>Conclusion</p> <p>Our findings suggest a protective effect of APOBEC3 for HIV and SIV <it>in vivo </it>and indicate regulation of APOBEC3 by interferon during early infection and by contribution of other, hitherto undefined factors at later disease stages. Elucidating the regulatory mechanisms leading to increased APOBEC3 mRNA levels in LTNPs could help to develop new therapies against HIV.</p

Capacity-building and participatory research development of a community-based Nutrition and Exercise Lifestyle Intervention Program (NELIP) for pregnant and postpartum Aboriginal women: Information gathered from talking circles

Objectives were to gather information from Talking Circles of Aboriginal women who participated in a maternal Nutrition and Exercise Lifestyle Intervention Program (NELIP) to identify strategies to bring NELIP into the community. Twelve First Nations women participated. Several main themes were identified regarding health: balance, knowledge/education and time management. Benefits of the NELIP were improvement in health, stamina, stress, and a healthy baby, no gestational diabetes and a successful home birth, with social support as an important contributing factor for success. Suggestions for improvement for the NELIP included group walking, and incorporating more traditional foods into the meal plan. The information gathered is the first step in determining strategies using participatory research and capacity-building to develop a community-based NELIP for pregnant Aboriginal women

Nutrition and exercise prevent excess weight gain in overweight pregnant women

Purpose: To determine the effect of a Nutrition and Exercise Lifestyle Intervention Program (NELIP) for overweight (OW) and obese (OB) pregnant women on pregnancy weight gain, birth weight, and maternal weight retention at 2 months postpartum. Methods: This is a single-arm intervention matched by prepregnant body mass index, age, and parity to a historical cohort (4:1). Women with a prepregnancy body mass index of\u3e25.0 kg•m (N = 65) participated in a NELIP starting at 16-20 wk of pregnancy, continuing until delivery. NELIP consisted of an individualized nutrition plan with total energy intake of approximately 2000 kcal•d (8360 kJ•d) and 40%-55% of total energy intake from carbohydrate. Exercise consisted of a walking program (30% HR reserve), three to four times per week, using a pedometer to count steps. Matched historical cohort (MC; N = 260) was from a large local perinatal database. Results: Weight gained by women on the NELIP was 6.8 ± 4.1 kg (0.38 ± 0.2 kg•wk), with a total pregnancy weight gain of 12.0 ± 5.7 kg. Excessive weight gain occurred before NELIP began at 16 wk of gestation. Eighty percent of the women did not exceed recommended pregnancy weight gain on NELIP. Weight retention at 2 months postpartum was 2.2 ± 5.6 kg with no difference between the OW and the OB women on NELIP. Mean birth weight was not different between NELIP (3.59 ± 0.5 kg) and MC (3.56 ± 0.6 kg, P \u3e 0.05). Conclusions: NELIP reduces the risk of excessive pregnancy weight gain with minimal weight retention at 2 months postpartum in OW and OB women. This intervention may assist OW and OB women in successful weight control after childbirth. Copyright © 2010 by the American College of Sports Medicine

Mid-term effects on ecosystem services of quarry restoration with Technosols under Mediterranean conditions : 10-year impacts on soil organic carbon and vegetation development

Ajuts : This study was funded by the Department of Territory and Sus-tainability of the Government of Catalonia through the project"Research and innovation on the control and the restoration ofextractive activities.The use of Technosols for the restoration of limestone quarries overcomes the usual "in situ" scarcity of soil and/or its poor quality. The use of mine spoils, improved with mineral and/or organic amendments, could be an efficient and environmentally friendly option. Properly treated sewage sludge from urban wastewater treatment plants could be a suitable organic amendment and fertilizer (rich in N and P) whenever its pollutant burden is low (heavy metals and/or organic pollutants). Its appropriate use could improve essential soil physical and chemical properties and, therefore, promote key ecosystem services of restored areas, such as biomass production and carbon sequestration, as well as biodiversity and landscape recovery. However, the mid-term impacts of these restoration practices on soil functioning and their services have rarely been reported in the available literature. In this study we assess the mid-term effects (10 years) of the use of sewage sludge as a Technosol amendment on soil organic carbon (SOC), nutrient status, and plant development in several restored quarries. Soils restored using sewage sludge showed a threefold increase in SOC compared to the corresponding unamended ones, despite the moderate sludge dosage applied (below 50 tonnes/ha). Plant cover was also higher in amended soils, and recruitment was not affected by sludge amendment at these doses. This study demonstrates that, used at an appropriate rate, sewage sludge is a good alternative for the valorization of mine spoils in quarry restoration, improving some important regulatory ecosystem services such as carbon sequestration, without compromising woody plant encroachment

Mucosal prior to systemic application of recombinant adenovirus boosting is more immunogenic than systemic application twice but confers similar protection against SIV-challenge in DNA vaccine-primed macaques

AbstractWe investigated the immunogenicity and efficacy of a bimodal prime/boost vaccine regimen given by various routes in the Simian immunodeficiency virus (SIV) rhesus monkey model for AIDS. Twelve animals were immunized with SIV DNA-vectors followed by the application of a recombinant adenovirus (rAd5) expressing the same genes either intramuscularly (i.m.) or by oropharyngeal spray. The second rAd5-application was given i.m. All vaccinees plus six controls were challenged orally with SIVmac239 12 weeks post-final immunization.Both immunization strategies induced strong SIV Gag-specific IFN-γ and T-cell proliferation responses and mediated a conservation of CD4+ memory T-cells and a reduction of viral load during peak viremia following infection. Interestingly, the mucosal group was superior to the systemic group regarding breadth and strength of SIV-specific T-cell responses and exhibited lower vector specific immune responses. Therefore, our data warrant the inclusion of mucosal vector application in a vaccination regimen which makes it less invasive and easier to apply