35 research outputs found
Imperfect Tests, Pervasive Pathogens, and Variable Demographic Performance: Thoughts on Managing Bighorn Sheep Respiratory Disease
Respiratory disease (pneumonia) has been a persistent challenge for bighorn sheep (Ovis canadensis) conservation and its cause has been attributed to numerous bacteria including Mycoplasma ovipneumoniae and several Pasteurellaceae family species. This study sought to investigate efficacy of diagnostic protocols in detecting Pasteurellaceae and Mycoplasma ovipneumoniae, generate sampling recommendations for different protocols, assess the distribution of these disease agents among 17 bighorn sheep populations in Montana and Wyoming, and evaluate what associations existed between detection of these agents and demographic performance of bighorn sheep populations. Analysis of replicate samples from individual bighorn sheep revealed that detection probability for regularlyused diagnostic protocols was generally low (<50%) for Pasteurellaceae and was high (>70%) for Mycoplasma ovipneumoniae, suggesting that routine pathogen sampling likely mischaracterizes respiratory pathogen communities. Power analyses found that most pathogen species could be detected with 80% confidence at the population-level by conducting regularly-used protocols multiple times per animal. Each pathogen species was detected in over half of the study populations, but after accounting for detection probability there was low confidence in negative test results for populations where Pasteurellaceae species were not detected. Seventy-six percent of study populations hosted both Mycoplasma ovipneumoniae and Pasteurellaceae pathogens, yet a number of these populations were estimated to have positive population growth rates and recruitment rates greater than 30%. Overall, the results of this work suggest that bighorn sheep respiratory disease may be mitigated by manipulating population characteristics and respiratory disease epizootics could be caused by pathogens already resident in bighorn sheep population
Distinct H-2-linked Ir genes control both antibody and T cell responses to different determinants on the same antigen, myoglobin
The murine antibody and T lymphocyte proliferative responses to sperm whale myoglobin (Mb) were found to be under control of two distinct H-2-linked immune response (Ir) genes (Ir-Mb-1, mapping in the I-A subregion, and Ir-Mb-2, mapping in I-C). H-2(d) mice (B10.D2 and DBA/2), with both genes, were high responders to Mb and its fragments for both antibody secretion and T cell proliferation, while H-2(b) (B10) and H-2(k) (B10.BR) mice were low responders. Strains with only Ir-Mb-2 [B10.A and B10.A(5R)], which were intermediate responders to Mb, made antibodies to and proliferated in response to the NH(2)-terminal fragment (1-55) but not the COOH-terminal fragment (132-153) when immunized with Mb. In contrast, mice carrying only the Ir-Mb-1 gene (D2.GD and B10.GD) made antibodies to and proliferated in response to both fragments. However, their proliferation to fragment (1-55) was often lower than that of their congenic high responders (DBA/2 and B10.D2, respectively), possibly because they respond to only some of the determinants on this NH(2)-terminal fragment. Thus, these data demonstrate that distinct Ir genes, mapping in separate I-subregions of H-2, control responses to different antigenic determinants on the same protein molecule. Moreover, the gene that controls the T lymphocyte responses to a given determinant also controls production of antibodies specific for that same determinant (or a closely associated one)
Dialysis Catheter–Related Bloodstream Infections: A Cluster-Randomized Trial of the ClearGuard HD Antimicrobial Barrier Cap
BackgroundThe rate of bloodstream infections (BSIs) is disproportionately high in hemodialysis (HD) patients with central venous catheters (CVCs) versus those with permanent accesses, contributing to poorer outcomes, such as increased rates of death and hospitalizations.Study Design12-month, prospective, cluster-randomized, multicenter, open-label trial.Setting & Participants40 Fresenius Medical Care North America dialysis facilities were matched and paired by positive blood culture rate and number of patients with CVCs and then cluster-randomized with 20 in each study group. 2,470 patients participated in the study (1,245, intervention group; 1,225, control group), accruing approximately 350,000 CVC-days.InterventionUse of ClearGuard HD Antimicrobial Barrier Caps versus use of standard CVC caps; assigned at the facility level.OutcomePrimary end point was positive blood culture rate as an indicator of BSI rate.MeasurementsPositive blood cultures, hospital admissions for BSI, hospitalization-days for BSI, intravenous antibiotic starts, and CVC-days.ResultsBaseline positive blood culture rates were similar (P=0.8) between groups. Use of ClearGuard HD caps for 12 months was associated with a 56% lower BSI rate versus use of standard CVC caps (0.26 vs 0.59/1,000 CVC-days, respectively; P=0.01). When considering sustained use (defined as last 6 months of the study), the intervention versus the control was associated with a 69% lower BSI rate (0.22 vs 0.72/1,000 CVC-days, respectively; P=0.01), 43% fewer hospital admissions for BSI (0.28 vs 0.48/1,000 CVC-days, respectively; P=0.04), and 51% fewer hospitalization days for BSI (2.42 vs 4.94/1,000 CVC-days, respectively; P=0.04). No device-related adverse events were reported.LimitationsStudy was open label; patients occasionally received HD at nonresearch facilities; patients did not receive the intervention when hospitalized.ConclusionsThe findings show that use of ClearGuard HD Antimicrobial Barrier Caps, when compared with standard CVC caps, significantly lowers rates of catheter-related BSIs and hospital admissions for BSI in HD patients using CVCs
Acyl CoA synthetase 5 (ACSL5) ablation in mice increases energy expenditure and insulin sensitivity and delays fat absorption
Objective: The family of acyl-CoA synthetase enzymes (ACSL) activates fatty acids within cells to generate long chain fatty acyl CoA (FACoA). The differing metabolic fates of FACoAs such as incorporation into neutral lipids, phospholipids, and oxidation pathways are differentially regulated by the ACSL isoforms. In vitro studies have suggested a role for ACSL5 in triglyceride synthesis; however, we have limited understanding of the in vivo actions of this ACSL isoform. Methods: To elucidate the in vivo actions of ACSL5 we generated a line of mice in which ACSL5 expression was ablated in all tissues (ACSL5−/−). Results: Ablation of ACSL5 reduced ACSL activity by ∼80% in jejunal mucosa, ∼50% in liver, and ∼37% in brown adipose tissue lysates. Body composition studies revealed that ACSL5−/−, as compared to control ACSL5loxP/loxP, mice had significantly reduced fat mass and adipose fat pad weights. Indirect calorimetry studies demonstrated that ACSL5−/− had increased metabolic rates, and in the dark phase, increased respiratory quotient. In ACSL5−/− mice, fasting glucose and serum triglyceride were reduced; and insulin sensitivity was improved during an insulin tolerance test. Both hepatic mRNA (∼16-fold) and serum levels of fibroblast growth factor 21 (FGF21) (∼13-fold) were increased in ACSL5−/− as compared to ACSL5loxP/loxP. Consistent with increased FGF21 serum levels, uncoupling protein-1 gene (Ucp1) and PPAR-gamma coactivator 1-alpha gene (Pgc1α) transcript levels were increased in gonadal adipose tissue. To further evaluate ACSL5 function in intestine, mice were gavaged with an olive oil bolus; and the rate of triglyceride appearance in serum was found to be delayed in ACSL5−/− mice as compared to control mice. Conclusions: In summary, ACSL5−/− mice have increased hepatic and serum FGF21 levels, reduced adiposity, improved insulin sensitivity, increased energy expenditure and delayed triglyceride absorption. These studies suggest that ACSL5 is an important regulator of whole-body energy metabolism and ablation of ACSL5 may antagonize the development of obesity and insulin resistance. Keywords: Dietary fat absorption, Acyl-CoA, ACSL, Intestine, Liver, FGF2
An Institutional Perspective on Prehispanic Maya Residential Variation: Settlement and Community at San Estevan, Belize
Interaural Attenuation of a Click Stimulus Using Deep and Shallow Placement of an Insert Earphone
Dialysis Catheter–Related Bloodstream Infections: A Cluster-Randomized Trial of the ClearGuard HD Antimicrobial Barrier Cap
Desarrollo de una prueba de inteligibilidad de habla en ambientes ruidosos para niños en edad escolar
Respiratory pathogens and their association with population performance in Montana and Wyoming bighorn sheep populations.
Respiratory disease caused by Mycoplasma ovipneumoniae and Pasteurellaceae poses a formidable challenge for bighorn sheep (Ovis canadensis) conservation. All-age epizootics can cause 10-90% mortality and are typically followed by multiple years of enzootic disease in lambs that hinders post-epizootic recovery of populations. The relative frequencies at which these epizootics are caused by the introduction of novel pathogens or expression of historic pathogens that have become resident in the populations is unknown. Our primary objectives were to determine how commonly the pathogens associated with respiratory disease are hosted by bighorn sheep populations and assess demographic characteristics of populations with respect to the presence of different pathogens. We sampled 22 bighorn sheep populations across Montana and Wyoming, USA for Mycoplasma ovipneumoniae and Pasteurellaceae and used data from management agencies to characterize the disease history and demographics of these populations. We tested for associations between lamb:ewe ratios and the presence of different respiratory pathogen species. All study populations hosted Pasteurellaceae and 17 (77%) hosted Mycoplasma ovipneumoniae. Average lamb:ewe ratios for individual populations where both Mycoplasma ovipneumoniae and Pasteurellaceae were detected ranged from 0.14 to 0.40. However, average lamb:ewe ratios were higher in populations where Mycoplasma ovipneumoniae was not detected (0.37, 95% CI: 0.27-0.51) than in populations where it was detected (0.25, 95% CI: 0.21-0.30). These findings suggest that respiratory pathogens are commonly hosted by bighorn sheep populations and often reduce recruitment rates; however ecological factors may interact with the pathogens to determine population-level effects. Elucidation of such factors could provide insights for management approaches that alleviate the effects of respiratory pathogens in bighorn sheep. Nevertheless, minimizing the introduction of novel pathogens from domestic sheep and goats remains imperative to bighorn sheep conservation
RespiratoryPathogenDetectionData.xlsx
Detection histories of respiratory pathogens for individual bighorn sheep that were sampled using several specified diagnostic protocols