Consistent changes in muscle metabolism underlie dive performance across multiple lineages of diving ducks

Diving animals must sustain high activity with limited O₂ stores to successfully capture prey. Studies suggest that increasing body O₂ stores supports breath-hold diving, but less is known about metabolic specializations that underlie underwater locomotion. We measured maximal activities of 10 key enzymes in locomotory muscles (gastrocnemius and pectoralis) to identify biochemical changes associated with diving in pathways of oxidative and substrate-level phosphorylation and compared them across three groups of ducks—the longest diving sea ducks (eight spp.), the mid-tier diving pochards (three spp.) and the non-diving dabblers (five spp.). Relative to dabblers, both diving groups had increased activities of succinate dehydrogenase and cytochrome c oxidase, and sea ducks further showed increases in citrate synthase (CS) and hydroxyacyl-CoA dehydrogenase (HOAD). Both diving groups had relative decreases in capacity for anaerobic metabolism (lower ratio of lactate dehydrogenase to CS), with sea ducks also showing a greater capacity for oxidative phosphorylation and lipid oxidation (lower ratio of pyruvate kinase to CS, higher ratio of HOAD to hexokinase). These data suggest that the locomotory muscles of diving ducks are specialized for sustaining high rates of aerobic metabolism, emphasizing the importance of body O₂ stores for dive performance in these species

It takes two: Evidence for reduced sexual conflict over parental care in a biparental canid

In biparental systems, sexual conflict over parental investment predicts that the parent providing care experiences greater reproductive costs. This inequality in parental contribution is reduced when offspring survival is dependent on biparental care. However, this idea has received little empirical attention. Here, we determined whether mothers and fathers differed in their contribution to care in a captive population of coyotes (Canis latrans). We performed parental care assays on 8 (n = 8 males, 8 females) mated pairs repeatedly over a 10-week period (i.e., 5–15 weeks of litter age) when pairs were first-time breeders (2011), and again as experienced breeders (2013). We quantified consistent individual variation (i.e., repeatability) in 8 care behaviors and examined within- and among-individual correlations to determine if behavioral plasticity within or parental personality across seasons varied by sex. Finally, we extracted hormone metabolites (i.e., cortisol and testosterone) from fecal samples collected during gestation to describe potential links between hormonal mechanisms and individual consistency in parental behaviors. Parents differed in which behaviors were repeatable: mothers demonstrated consistency in provisioning and pup-directed aggression, whereas fathers were consistent in pup checks. However, positive within-individual correlations for identical behaviors (e.g., maternal versus paternal play) suggested that the rate of change in all behaviors except provisioning was highly correlated between the sexes. Moreover, positive among-individual correlations among 50% of identical behaviors suggested that personality differences across parents were highly correlated. Lastly, negative among-individual correlations among pup-directed aggression, provisioning, and gestational testosterone in both sexes demonstrated potential links between preparental hormones and labile parental traits. We provide novel evidence that paternal contribution in a biparental species reaches near equivalent rates of their partners

Surviving Mousepox Infection Requires the Complement System

Poxviruses subvert the host immune response by producing immunomodulatory proteins, including a complement regulatory protein. Ectromelia virus provides a mouse model for smallpox where the virus and the host's immune response have co-evolved. Using this model, our study investigated the role of the complement system during a poxvirus infection. By multiple inoculation routes, ectromelia virus caused increased mortality by 7 to 10 days post-infection in C57BL/6 mice that lack C3, the central component of the complement cascade. In C3−/− mice, ectromelia virus disseminated earlier to target organs and generated higher peak titers compared to the congenic controls. Also, increased hepatic inflammation and necrosis correlated with these higher tissue titers and likely contributed to the morbidity in the C3−/− mice. In vitro, the complement system in naïve C57BL/6 mouse sera neutralized ectromelia virus, primarily through the recognition of the virion by natural antibody and activation of the classical and alternative pathways. Sera deficient in classical or alternative pathway components or antibody had reduced ability to neutralize viral particles, which likely contributed to increased viral dissemination and disease severity in vivo. The increased mortality of C4−/− or Factor B−/− mice also indicates that these two pathways of complement activation are required for survival. In summary, the complement system acts in the first few minutes, hours, and days to control this poxviral infection until the adaptive immune response can react, and loss of this system results in lethal infection

Age, Disease Severity and Ethnicity Influence Humoral Responses in a Multi-Ethnic COVID-19 Cohort

The COVID-19 pandemic has affected all individuals across the globe in some way. Despite large numbers of reported seroprevalence studies, there remains a limited understanding of how the magnitude and epitope utilization of the humoral immune response to SARS-CoV-2 viral anti-gens varies within populations following natural infection. Here, we designed a quantitative, multi-epitope protein microarray comprising various nucleocapsid protein structural motifs, including two structural domains and three intrinsically disordered regions. Quantitative data from the microarray provided complete differentiation between cases and pre-pandemic controls (100% sensitivity and specificity) in a case-control cohort (n = 100). We then assessed the influence of disease severity, age, and ethnicity on the strength and breadth of the humoral response in a multi-ethnic cohort (n = 138). As expected, patients with severe disease showed significantly higher antibody titers and interestingly also had significantly broader epitope coverage. A significant increase in antibody titer and epitope coverage was observed with increasing age, in both mild and severe disease, which is promising for vaccine efficacy in older individuals. Additionally, we observed significant differences in the breadth and strength of the humoral immune response in relation to ethnicity, which may reflect differences in genetic and lifestyle factors. Furthermore, our data enabled localization of the immuno-dominant epitope to the C-terminal structural domain of the viral nucleocapsid protein in two independent cohorts. Overall, we have designed, validated, and tested an advanced serological assay that enables accurate quantitation of the humoral response post natural infection and that has revealed unexpected differences in the magnitude and epitope utilization within a population

Blood‐ and muscle‐O2 storage capacity in North American diving ducks

Breath‐hold diving presents air‐breathing vertebrates with the challenge of maintaining aerobic respiration while exercising underwater. Adaptive increases in the oxygen (O2) storage capacity in the lungs, blood, or muscle tissues can enhance these reserves and greatly extend aerobic foraging time underwater. Here, we report blood‐ and muscle‐O2 storage parameters (blood hemoglobin concentration ([Hb]), hematocrit, and myoglobin concentration ([Mb]) in the pectoralis and gastrocnemius) for 16 species of diving and dabbling ducks found in North America, and investigate which parameters are correlated with the diving behaviors reported in both the sea ducks (Mergini) and the pochards (Aythini). Both [Hb] in the blood and [Mb] in the gastrocnemius, a major leg muscle used in propulsion for these predominantly leg‐propelled divers, were significantly higher in the sea ducks compared to the dabblers (Anatini). The pochards also showed a significant increase in [Hb] and were intermediate between the sea ducks and the dabblers in hematocrit and [Mb] in the gastrocnemius. Among these four variables and total body mass, [Mb] in the gastrocnemius was the most significant predictor of mean species dive time, and these two variables were correlated across the phylogeny. Our results indicate that the observed changes in O2 storage capacity in the blood and muscles are positively correlated with diving behavior in two clades of ducks, such that larger increases are correlated with longer dive times

Pulmonary blastomycosis presenting as primary lung cancer

Abstract Background Blastomycosis is an endemic mycosis in North America that is caused by the dimorphic fungus Blastomyces dermatitidis. The illness is a systemic disease with a wide variety of pulmonary and extra-pulmonary manifestations. The initial presentation of blastomycosis may easily be mistaken for other infectious or non-infectious etiologies. Case presentation We present the case of a 52-year-old African-American male and former smoker that presented to his primary care provider with a 2-week history of non-productive cough, night sweats and weight loss. Initially diagnosed with primary lung malignancy, the patient was subsequently found to have pulmonary blastomycosis mimicking lung cancer. The patient underwent a successful course of treatment with posaconazole. Conclusions Chronic blastomycosis can present with clinical and radiographic features indistinguishable from thoracic malignancies. There is no clinical syndrome specific for blastomycosis, thus a high degree of suspicion is required for early diagnosis. In this case report, we review recent evidence in radiographic features, diagnostic considerations and treatment of the disease

Advance Care Planning Coaching in CKD Clinics: A Pragmatic Randomized Clinical Trial

Rationale & Objective: Although guidelines recommend more and earlier advance care planning (ACP) for patients with chronic kidney disease (CKD), scant evidence exists to guide incorporation of ACP into clinical practice for patients with stages of CKD prior to kidney failure. Involving nephrology team members in addition to primary care providers in this important patient-centered process may increase its accessibility. Our study examined the effect of coaching implemented in CKD clinics on patient engagement with ACP. Study Design: Multicenter, pragmatic randomized controlled trial. Setting & Participants: Three CKD clinics in different states participated: 273 patients consented to participate, 254 were included in analysis. Eligible patients were 55 years or older, had stage 3-5 CKD, and were English speaking. Intervention: Nurses or social workers with experience in nephrology or palliative care delivered individualized in-person ACP sessions. The enhanced control group was given Make Your Wishes About You (MY WAY) education materials and was verbally encouraged to bring their completed advance directives to the clinic. Outcome: Primary outcome measures were scores on a 45-point ACP engagement scale at 14 weeks and a documented advance directive or portable medical order at 16 weeks after enrollment. Results: Among 254 participants analyzed, 46.5% were 65-74 years of age, and 54% had CKD stage 3. The coached patients scored 1.9 points higher at 14 weeks on the ACP engagement scale (β = 1.87 [95% CI, 0.13-3.64]) adjusted for baseline score and site. Overall, 32.8% of intervention patients (41 of 125) had an advance directive compared with 17.8% (23 of 129) of patients in the control group. In a site-adjusted multivariable model, coached patients were 79% more likely to have a documented advance directive or portable medical order (adjusted risk ratio, 1.79 [95% CI, 1.18-2.72]), with the impact principally evident at only 1 study site. Limitations: Small number of study sites and possible unrepresentativeness of the broader CKD population by study participants. Conclusions: Individualized coaching may be effective in enhancing ACP, but its impact may be influenced by the health care environment where it is delivered. Funding: The Patrick and Catherine Weldon Donaghue Medical Research Foundation, via the Greater Value Portfolio. Trial Registration: Registered at ClinicalTrials.gov with study number NCT03506087

Invisible Wounds of War: Psychological and Cognitive Injuries, Their Consequences, and Services to Assist Recovery

Since October 2001, approximately 1.64 million U.S. troops have been deployed for Operations Enduring Freedom and Iraqi Freedom (OEF/OIF) in Afghanistan and Iraq. Early evidence suggests that the psychological toll of these deployments may be disproportionately high compared with the physical injuries of combat. Research has focused primarily on three conditions: post-traumatic stress disorder (PTSD), depression, and traumatic brain injury (TBI). Karney et al. review the empirical literature on these three conditions, focusing on research that supports projections about the likely outcomes for OEF/OIF veterans and their families. These include an increased risk of suicide, substance abuse, and cardiovascular disease. Mental health conditions among veterans are also associated with reduced work productivity and future job prospects and may be a precursor to homelessness. Post-combat mental health disorders also affect servicemembers' spouses and children: For example, each of the three disorders has been linked to intimate partner violence and divorce. The authors also emphasize that it is common for veterans with one of the three conditions -- PTSD, depression, or TBI -- to also develop another of the three, and such individuals tend to experience more severe symptoms, poorer treatment outcomes, and more disability in social and occupation function. Karney et al. conclude with two series of recommendations: one for future research, and one for policy and interventions to mitigate the consequences of post-combat mental health conditions