Investigation of Protease Activity in Early Postmortem MuscleSubjected to Alternative Chilling Conditions

The objective of this study was two-fold: 1) determine the conditions (temperature, pH) that exist in early postmortem muscle of normally-chilled and delay-chilled beef carcasses to provide a model for in vitro work, and 2) determine the mechanism by which specific early postmortem temperature/pH conditions found in normally-chilled and delay-chilled muscle influence the enzymes that regulate the aging process in vitro. For objective 1, seven market-ready calves (HCW 848 ± 17.5 lb) were harvested with the right sides subjected to normal chilling (2.3°C) and the left sides subjected to ambient temperature (delay chilling; 22.6°C) for an additional 4.75 h and then allowed to normally chill. Carcasses were monitored for longissimus dorsi muscle temperature, pH, postmortem proteolysis, and sarcomere length. Steaks aged for 1, 7 and 14 d were evaluated for tenderness using Warner-Bratzler shear force (WBSF) and carcasses were swabbed over the rump, flank, and brisket for total aerobic plate counts. Delay-chilled carcasses had a faster pH decline and a slower rate of carcass cooling (P\u3c0.05). No differences were seen in sarcomere length, total plate counts, or in postmortem proteolysis of troponin T (TnT)(P\u3e0.05). WBSF was not different at 1 and 7 d (P\u3e0.05), but was less in steaks from normally-chilled carcasses at 14 d (P=0.0144). Further data analysis indicated a strong, negative correlation between 14 d WBSF and the change in pH from 6 to 12 hr postmortem (Figure 3, r = -0.8105, P=0.0004). These results were utilized to design the methodology for objective 2, where isolated myofibrils were subjected to μ-calpain digestion at 4 or 22°C with either a fast or slow initial pH decline. Digests were evaluated for pH, μ-calpain activity, and intact TnT degradation. Digestions with a fast initial pH decline had lower pH values in the early time points of the incubation (P\u3c0.05). No differences were detected in μ-calpain activity or in the degradation of intact TnT (P\u3e0.05) between the fast and slow pH decline treatments. Meanwhile, a temperature x time interaction was revealed in μ-calpain activity and in the degradation of intact TnT (P\u3c0.05). Additionally, intact TnT and μ-calpain activity decreased over time (P\u3c0.05) while warmer digestions resulted in a tendency for reduced μ-calpain activity (P=0.0854) and a significant reduction in intact TnT (P=0.0105)

Effects of space allocation within a deep-bedded finishing system on pig growth performance, fatty acid composition and pork quality

The objectives of the current study were to determine the degree to which space allocation in a deep-bedded system influences swine performance and pork quality. The deep-bedded method employed was hoop structures, which are large, tent-like shelters with cornstalks or straw for bedding. One hundred gilts ranging in weight from 59 to 71 kg were randomly assigned to treatments of low (0.70 m2 per pig, n = 50) or high (1.13 m2 per pig, n = 50) space allocation. During the 45-day experimental period, gilts were ad libitum fed a two-phase diet. Six gilts per treatment were used for carcass composition and pork quality evaluation for each replication. Five replications were conducted over a period of 4 months. Pigs finished with greater space allocation had smaller longissimusmuscle area and produced pork that appeared to be darker. Variations in fatty acid composition and lipid percentage of subcutaneous adipose and longissimus dorsi muscle were observed when space allocation was changed within hoop structures. Less space resulted in greater proportion of lipid present as polyunsaturated fatty acids. Greater space allocation resulted in lower total lipid in subcutaneous pork adipose tissue. Space allocation did not affect fat firmness. Replications spanned the months of August to November, with temperatures ranging from 32°C to −2°C within the hoop structure. As environmental temperature declined, the proportion of monounsaturated fatty acids increased. Providing more space during finishing in these systems had only a small affect on pig growth and pork quality. Variations observed from replication to replication at fluctuating temperatures provide insight to seasonal differences in growth and adipose tissue composition and firmness. Therefore, finishing pigs in these systems may lead to seasonal variation in lipid composition

The Physics of Star Cluster Formation and Evolution

© 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00689-4.Star clusters form in dense, hierarchically collapsing gas clouds. Bulk kinetic energy is transformed to turbulence with stars forming from cores fed by filaments. In the most compact regions, stellar feedback is least effective in removing the gas and stars may form very efficiently. These are also the regions where, in high-mass clusters, ejecta from some kind of high-mass stars are effectively captured during the formation phase of some of the low mass stars and effectively channeled into the latter to form multiple populations. Star formation epochs in star clusters are generally set by gas flows that determine the abundance of gas in the cluster. We argue that there is likely only one star formation epoch after which clusters remain essentially clear of gas by cluster winds. Collisional dynamics is important in this phase leading to core collapse, expansion and eventual dispersion of every cluster. We review recent developments in the field with a focus on theoretical work.Peer reviewe

A Germline Variant at 8q24 Contributes to Familial Clustering of Prostate Cancer in Men of African Ancestry

Although men of African ancestry have a high risk of prostate cancer (PCa), no genes or mutations have been identified that contribute to familial clustering of PCa in this population. We investigated whether the African ancestry–specific PCa risk variant at 8q24, rs72725854, is enriched in men with a PCa family history in 9052 cases, 143 cases from high-risk families, and 8595 controls of African ancestry. We found the risk allele to be significantly associated with earlier age at diagnosis, more aggressive disease, and enriched in men with a PCa family history (32% of high-risk familial cases carried the variant vs 23% of cases without a family history and 12% of controls). For cases with two or more first-degree relatives with PCa who had at least one family member diagnosed at age <60 yr, the odds ratios for TA heterozygotes and TT homozygotes were 3.92 (95% confidence interval [CI] = 2.13–7.22) and 33.41 (95% CI = 10.86–102.84), respectively. Among men with a PCa family history, the absolute risk by age 60 yr reached 21% (95% CI = 17–25%) for TA heterozygotes and 38% (95% CI = 13–65%) for TT homozygotes. We estimate that in men of African ancestry, rs72725854 accounts for 32% of the total familial risk explained by all known PCa risk variants. Patient summary: We found that rs72725854, an African ancestry–specific risk variant, is more common in men with a family history of prostate cancer and in those diagnosed with prostate cancer at younger ages. Men of African ancestry may benefit from the knowledge of their carrier status for this genetic risk variant to guide decisions about prostate cancer screening. © 2020 The AuthorsThe African ancestry–specific prostate cancer risk variant at 8q24, rs72725854, is enriched in men diagnosed at younger ages and men with a prostate cancer family history. Carriers of this risk allele would benefit from regular and earlier prostate cancer screening

Padrão geográfico de diversidade genética em populações naturais de Pau-rosa (Aniba rosaeodora), na Amazônia Central

Rosewood (Aniba rosaeodora Ducke, Lauraceae) is an Amazonian evergreen tree and a source of the purest linalool, the main component of its essential oil, which is very valuable in the international perfumery market. After decades of over-exploitation it is currently considered as threatened. We evaluated the genetic diversity and its distribution in four populations in Central Amazonia. Thirty-five reliable RAPD markers were generated, of which 32 were polymorphic (91.4%). Variation was higher within the populations (76.5%; p < 0.0001) and geographic distribution contributed to population differentiation (23.4%; p < 0.0001). The Amazon River had a small influence on gene flow (3.3%; p < 0.0001), but we identified evidence of gene flow across the river. There were significant differences in marker frequencies (p < 0.05), in agreement with the low gene flow (Nm = 2.02). The correlation between genetic distance and gene flow was - 0.95 (p = 0.06) and between geographic distance and gene flow was -0.78 (p = 0.12). There was a geographic cline of variability across an East-West axis, influenced as well by the Amazon River, suggesting the river could be a barrier to gene flow. Although threatened, these Rosewood populations retain high diversity, with the highest levels in the Manaus population, which has been protected for over 42 years in a Reserve.O Pau-rosa (Aniba rosaeodora Ducke, Lauraceae) é uma árvore amazônica fonte do mais puro linalol, o qual é o principal componente do seu óleo essencial e muito valioso no mercado internacional de perfumaria. Após várias décadas de intensa exploração, a espécie foi levada à categoria de ameaçada de extinção. Quatro populações naturais distribuídas na bacia Amazônia Central foram avaliadas quanto ao nível e a distribuição da diversidade genética. Trinta e cinco marcadores RAPD reprodutíveis foram gerados, dos quais 32 foram polimórficos (91,4%). A diversidade foi maior dentro das populações (76,5%; p < 0,0001) e a distribuição geográfica contribuiu para a diferenciação entre as populações (23,4%; p < 0,0001). A AMOVA indicou que pode haver uma influência parcial do Rio Amazonas no fluxo gênico (3,3%; p < 0,0001), mas foram identificadas evidências de fluxo gênico atravessando o rio. Houve diferenças significativas nas freqüências dos marcadores (p < 0,05) e o fluxo gênico estimado foi relativamente baixo (Nm = 2,02). A correlação entre a distância genética e o fluxo gênico foi de - 0,95 (p = 0,06) e para a distância geográfica e o fluxo gênico foi de - 0,78 (p = 0,12). Houve um padrão geográfico de variabilidade ao longo do eixo Leste - Oeste, influenciado também pelo Rio Amazonas, o que sugere que o rio poderia funcionar como uma barreira para o fluxo gênico. Apesar de ameaçadas, estas populações de Pau-rosa possuem alta diversidade, com o maior valor na população de Manaus, que vem sendo protegida por 42 anos em uma reserva

Lung adenocarcinoma promotion by air pollutants

A complete understanding of how exposure to environmental substances promotes cancer formation is lacking. More than 70 years ago, tumorigenesis was proposed to occur in a two-step process: an initiating step that induces mutations in healthy cells, followed by a promoter step that triggers cancer development1. Here we propose that environmental particulate matter measuring ≤2.5 μm (PM2.5), known to be associated with lung cancer risk, promotes lung cancer by acting on cells that harbour pre-existing oncogenic mutations in healthy lung tissue. Focusing on EGFR-driven lung cancer, which is more common in never-smokers or light smokers, we found a significant association between PM2.5 levels and the incidence of lung cancer for 32,957 EGFR-driven lung cancer cases in four within-country cohorts. Functional mouse models revealed that air pollutants cause an influx of macrophages into the lung and release of interleukin-1β. This process results in a progenitor-like cell state within EGFR mutant lung alveolar type II epithelial cells that fuels tumorigenesis. Ultradeep mutational profiling of histologically normal lung tissue from 295 individuals across 3 clinical cohorts revealed oncogenic EGFR and KRAS driver mutations in 18% and 53% of healthy tissue samples, respectively. These findings collectively support a tumour-promoting role for PM2.5 air pollutants and provide impetus for public health policy initiatives to address air pollution to reduce disease burden

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo