Subregional DXA-derived vertebral bone mineral measures are stronger predictors of failure load in specimens with lower areal bone mineral density, compared to those with higher areal bone mineral density

Measurement of areal bone mineral density (aBMD) in intravertebral subregions may increase the diagnostic sensitivity of dual-energy X-ray absorptiometry (DXA)-derived parameters for vertebral fragility. This study investigated whether DXA-derived bone parameters in vertebral subregions were better predictors of vertebral bone strength in specimens with low aBMD, compared to those with higher aBMD. Twenty-five lumbar vertebrae (15 embalmed and 10 fresh-frozen) were scanned with posteroanterior- (PA) and lateral-projection DXA, and then mechanically tested in compression to ultimate failure. Whole-vertebral aBMD and bone mineral content (BMC) were measured from the PA- and lateral-projection scans and within 6 intravertebral subregions. Multivariate regression was used to predict ultimate failure load by BMC, adjusted for vertebral size and specimen fixation status across the whole specimen set, and when subgrouped into specimens with low aBMD and high aBMD. Adjusted BMC explained a substantial proportion of variance in ultimate vertebral load, when measured over the whole vertebral area in lateral projection (adjusted R2 0.84) and across the six subregions (ROIs 2–7) (adjusted R2 range 0.58–0.78). The association between adjusted BMC, either measured subregionally or across the whole vertebral area, and vertebral failure load, was increased for the subgroup of specimens with identified ‘low aBMD’, compared to those with ‘high aBMD’, particularly in the anterior subregion where the adjusted R2 differed by 0.44. The relative contribution of BMC measured in vertebral subregions to ultimate failure load is greater among specimens with lower aBMD, compared to those with higher aBMD, particularly in the anterior subregion of the vertebral body

Clinical and biomarker changes in premanifest Huntington disease show trial feasibility: A decade of the PREDICT-HD study

There is growing consensus that intervention and treatment of Huntington disease (HD) should occur at the earliest stage possible. Various early-intervention methods for this fatal neurodegenerative disease have been identified, but preventive clinical trials for HD are limited by a lack of knowledge of the natural history of the disease and a dearth of appropriate outcome measures. Objectives of the current study are to document the natural history of premanifest HD progression in the largest cohort ever studied and to develop a battery of imaging and clinical markers of premanifest HD progression that can be used as outcome measures in preventive clinical trials. Neurobiological predictors of Huntington’s disease is a 32-site, international, observational study of premanifest HD, with annual examination of 1013 participants with premanifest HD and 301 gene-expansion negative controls between 2001 and 2012. Findings document 39 variables representing imaging, motor, cognitive, functional, and psychiatric domains, showing different rates of decline between premanifest HD and controls. Required sample size and models of premanifest HD are presented to inform future design of clinical and preclinical research. Preventive clinical trials in premanifest HD with participants who have a medium or high probability of motor onset are calculated to be as resource-effective as those conducted in diagnosed HD and could interrupt disease 7–12years earlier. Methods and measures for preventive clinical trials in premanifest HD more than a dozen years from motor onset are also feasible. These findings represent the most thorough documentation of a clinical battery for experimental therapeutics in stages of premanifest HD, the time period for which effective intervention may provide the most positive possible outcome for patients and their families affected by this devastating disease

Surgical management of ascending aortic aneurysm and its complications

Ascending aortic aneurysms involving the proximal aortic arch, arising anywhere from the aortic valve to the innominate artery, represent various problems in which open surgery is generally required. Surgical options include excision of the aortic pathology or wrapping the aneurysm shell with an aortic Dacron graft. Intervention using the latter method can lead to extravasation of blood along the suture lines resulting in continuous bleeding within the periprosthetic space. The Cabrol technique was developed as a method for decompression of postoperative leaks by the formation of a conduit system from the periprosthetic space to the right atrium. The coronary ostia are anastomosed to a second graft in an end-to-end fashion, which is then anastomosed to the ascending aortic conduit side to side. The native aorta is then sewn around the prosthesis, hereby creating a shunt to drain anastomotic leakage. This shunt reduces postsurgical risk of pseudoaneurysm formation and normally closes a few days following surgery. We discuss the case of a patient who underwent Cabrol\u27s variation and six months later was demonstrated to have a patent shunt

Herbivores suppress soil microbes to influence carbon sequestration in the grazing ecosystem of the Trans-Himalaya

Understanding factors that regulate carbon (C) pools is of high importance for offsetting greenhouse-gas emissions. Soils represent a vast C pool, whose size and stability are strongly influenced by land-use. Grazing, by native herbivores and livestock, is the predominant land-use across over 40% of the terrestrial surface and influences over 109 Mg of soil-C annually in the world’s dry regions. The interactions between plants, grazers, and soil microbes, is of critical importance for this soil-C pool. However, soil microbial responses to grazing, and associated feedbacks, remain poorly understood. Grazing management policies are unable to adequately accommodate key interactions that are important for effective ecosystem stewardship. After 10-yr of experimental herbivore-exclusion in the semiarid Trans-Himalayan ecosystem, we measured grazer effects on soil microbial abundance in n = 30 herbivore exclosures, each paired with an adjacent control plot using substrate-induced respiration, microbial-carbon, and microbial-nitrogen (SIR, MBC, MBN). We found that grazing reduced soil microbial biomass by 13–16%, over the course of the vegetation growing season. But, the strength and direction of grazer effects varied through time at different points in the growing season. Grazing also shifted fungal:bacterial ratio towards dominance by fungi which were more tolerant of periodic dry-down and seasonal fluctuations in soil moisture than bacteria. So, grazer influence on microbial abundance and community composition may collectively play crucial roles in net soil-C dynamics. But, this effect is constrained by environmental factors, such as moisture availability. The projected climatic trend in the Trans-Himalaya is towards progressively wetter conditions, and this may counter grazer effect on microbes, alter microbial communities, and ultimately impact potential soil-C storage. So, accounting for projected changes in precipitation, in addition to managing stocking density of herbivores, may also be crucial for these large soil-C pools

In vivo colchicine manipulation for enhancing DH production efficiency in Triticum durum using Imperata cylindrica-mediated chromosome elimination approach

Durum wheat×Imperata cylindrica hybridization was carried out utilizing two durum wheat genotypes as maternal parents (A-9-30-1 and PDW 314) and I. cylindrica as a pollen source followed by in vivo application of colchicine to establish a standard protocol for colchicine application aimed at enhancement of doubled haploid production in durum wheat. Various concentrations of colchicine ranging from 500 to 7000 ppm were injected to the pollinated spikes at diferent time interval viz., 24 h, 48 h and 72 h after pollination. Application of 5000–7000 ppm colchicine at 48 h after pollination was established as the optimum colchicine dose for chromosome doubling as confrmed through cytological studies in durum wheat using I. cylindrica-mediated chromosome elimination approach. PDW 314 was identifed as a durum wheat genotype having more potential for doubled haploid induction via in vivo colchicine application than A-9-30-1. Identifcation of optimum dose of colchicine for application at in vivo level for induction of doubled haploids has opened new vistas in durum wheat improvement programme

Impact of Immunosuppression on T-cell Responses After mRNA-Based Sars-CoV-2 Vaccination

2022 American Transplant Congress22766-76