The "yin and yang" of the adrenal and gonadal systems in elite military men.

We recently established daily, free-living profiles of the adrenal hormone cortisol, the (primarily adrenal) anabolic precursor dehydroepiandrosterone (DHEA) and the (primarily gonadal) anabolic hormone testosterone in elite military men. A prevailing view is that adrenal and gonadal systems reciprocally modulate each other; however, recent paradigm shifts prompted the characterization of these systems as parallel, cooperative processes (i.e. the "positive coupling" hypothesis). In this study, we tested the positive coupling hypothesis in 57 elite military men by evaluating associations between adrenal and gonadal biomarkers across the day. Salivary DHEA was moderately and positively coupled with salivary cortisol, as was salivary testosterone. Anabolic processes (i.e. salivary DHEA and testosterone) were also positively and reliably coupled across the day. In multivariate models, salivary DHEA and cortisol combined to account for substantial variance in salivary testosterone concentrations across the day, but this was driven almost exclusively by DHEA. This may reflect choreographed adrenal release of DHEA with testicular and/or adrenal release of testosterone, systemic conversion of DHEA to testosterone, or both. DHEA and testosterone modestly and less robustly predicted cortisol concentrations; this was confined to the morning, and testosterone was the primary predictor. Altogether, top-down co-activation of adrenal and gonadal hormone secretion may complement bottom-up counter-regulatory functions to foster anabolic balance and neuronal survival; hence, the "yin and yang" of adrenal and gonadal systems. This may be an adaptive process that is amplified by stress, competition, and/or dominance hierarchy.

Body composition as a marker of performance and health in military personnel.

Introduction: Body composition standards are set to ensure operational readiness in active-duty military personnel. To meet body composition standards, some individuals, however, may engage in unhealthy weight control behaviors (i.e., weight cycling and disordered eating). The objectives of this review are to: (1) evaluate the evidence regarding body composition and the associations to physical and military specific performance; (2) discuss body composition and potential health consequences; and (3) examine the evidence of weight cycling and disordered eating behaviors in military personnel for weight control. Methods: A systematic search to identify peer-reviewed research articles was conducted in PubMed on 2/20/2023 using Medical Subject Headings (MeSH) including but not limited to "Military Personnel", "Tactical Athlete", "Weight Loss", "Body Composition", and "Weight Cycling". Results: A total of 225 research articles were identified. The list was narrowed down to articles from the last 20 years (2003-2023) in military personnel. Only studies in which percent body fat was directly measured were included resulting in 17 research articles for this review. Discussion: Evidence-based research is limited on the relationship between body composition and operational readiness. Weight cycling and disordered eating behaviors also has been reported for weight control, yet additional research is needed. Specifically, future research should focus on female service members, racial and ethnic differences, age, and postpartum status and include other service branches (i.e., Air Force and Navy). A comprehensive survey on weight cycling, disordered eating, and weight management would be valuable to determine the prevalence and extent of this issue. This information along with performance data would guide policy makers on the relevance and appropriateness of existing body composition standards.

Infection with the fox lungworm (Crenosoma vulpis) in two dogs from New England - Two clinical reports and updated geographic distribution in North America.

Crenosoma vulpis, the fox lungworm, is a helminth parasite endemic to the fox population of New England. Domestic dogs are susceptible to infection via ingestion of snails and slugs. Two dogs from New England were diagnosed with C. vulpis. The predominant clinical sign in both dogs was a chronic cough. Treatment with steroids and antibiotics only temporarily relieved clinical signs. Thoracic radiographs in both dogs revealed bronchial patterns. Endotracheal washes were performed in each dog revealing marked, mixed inflammation consisting mainly of neutrophils with eosinophils in lesser numbers. Helminth larvae could also be visualized on cytology. A fecal flotation revealed helminth larvae in one dog but failed to identify larvae in the second dog. The diagnosis of C. vulpis was confirmed via PCR analysis and sequencing of samples from both endotracheal washes. One dog was treated with fenbendazole (50 mg/kg PO q24h for 14 days), enrofloxacin (13 mg/kg PO q 24 h for 5 days), and a tapering protocol of prednisone (20 mg PO q12h for 5 days, 20 mg PO q24h for 5 days, then 20 mg PO q48h for 10 days). The second dog was treated with fenbendazole (50 mg/kg PO q24h for 10 days) with an additional 7 days of febantel and two doses of milbemycin, achieving complete resolution of clinical signs. This lungworm is becoming increasingly more prevalent in domestic dogs worldwide and may be more prevalent in New England than previously thought. Veterinary practitioners of New England should include this respiratory helminth as a differential in dogs with respiratory signs, and respiratory washes and Baermann fecal examinations are warranted in dogs presenting with non-specific respiratory clinical signs.

Short-Term RCT of Increased Dietary Potassium from Potato or Potassium Gluconate: Effect on Blood Pressure, Microcirculation, and Potassium and Sodium Retention in Pre-Hypertensive-to-Hypertensive Adults.

Increased potassium intake has been linked to improvements in cardiovascular and other health outcomes. We assessed increasing potassium intake through food or supplements as part of a controlled diet on blood pressure (BP), microcirculation (endothelial function), and potassium and sodium retention in thirty pre-hypertensive-to-hypertensive men and women. Participants were randomly assigned to a sequence of four 17 day dietary potassium treatments: a basal diet (control) of 60 mmol/d and three phases of 85 mmol/d added as potatoes, French fries, or a potassium gluconate supplement. Blood pressure was measured by manual auscultation, cutaneous microvascular and endothelial function by thermal hyperemia, utilizing laser Doppler flowmetry, and mineral retention by metabolic balance. There were no significant differences among treatments for end-of-treatment BP, change in BP over time, or endothelial function using a mixed-model ANOVA. However, there was a greater change in systolic blood pressure (SBP) over time by feeding baked/boiled potatoes compared with control (-6.0 mmHg vs. -2.6 mmHg; p = 0.011) using contrast analysis. Potassium retention was highest with supplements. Individuals with a higher cardiometabolic risk may benefit by increasing potassium intake. This trial was registered at ClinicalTrials.gov as NCT02697708.

Short-Term Supplemental Dietary Potassium from Potato and Potassium Gluconate: Effect on Calcium Retention and Urinary pH in Pre-Hypertensive-to-Hypertensive Adults.

Potassium supplementation has been associated with reduced urinary calcium (Ca) excretion and increased Ca balance. Dietary interventions assessing the impact of potassium on bone are lacking. In this secondary analysis of a study designed primarily to determine blood pressure effects, we assessed the effects of potassium intake from potato sources and a potassium supplement on urinary Ca, urine pH, and Ca balance. Thirty men (n = 15) and women (n = 15) with a mean ± SD age and BMI of 48.2 ± 15 years and 31.4 ± 6.1 kg/m2, respectively, were enrolled in a cross-over, randomized control feeding trial. Participants were assigned to a random order of four 16-day dietary potassium interventions including a basal diet (control) of 2300 mg/day (~60 mmol/day) of potassium, and three phases of an additional 1000 mg/day (3300 mg/day(~85 mmol/day) total) of potassium in the form of potatoes (baked, boiled, or pan-heated), French fries (FF), or a potassium (K)-gluconate supplement. Calcium intake for all diets was approximately 700-800 mg/day. Using a mixed model ANOVA there was a significantly lower urinary Ca excretion in the K-gluconate phase (96 ± 10 mg/day) compared to the control (115 ± 10 mg/day; p = 0.027) and potato (114 ± 10 mg/day; p = 0.033). In addition, there was a significant difference in urinary pH between the supplement and control phases (6.54 ± 0.16 vs. 6.08 ± 0.18; p = 0.0036). There were no significant differences in Ca retention. An increased potassium intake via K-gluconate supplementation may favorably influence urinary Ca excretion and urine pH. This trial was registered at ClinicalTrials.gov as NCT02697708.

Are the Effects of Oral and Vaginal Contraceptives on Bone Formation in Young Women Mediated via the Growth Hormone-IGF-I Axis?

Purpose: Combined hormonal contraceptive therapy has been associated with negative bone mineral density outcomes that may be route-dependent [i.e., combined oral contraception (COC) vs. contraceptive vaginal ring (CVR)] and involve the hepatic growth hormone (GH)/insulin-like growth factor-I (IGF-I) axis. The objective of the pilot study was to assess the impact of route of contraceptive administration on IGF-I and procollagen type I N-terminal propeptide (PINP) responses to an IGF-I Generation Test. We hypothesized that the peak rise in IGF-I and PINP concentration and area under the curve (AUC) would be attenuated following COC, but not CVR, use. Methods: Healthy, premenopausal women not taking hormonal contraception were recruited. Women were enrolled in the control group (n = 8) or randomly assigned to COC (n = 8) or CVR (n = 8) for two contraceptive cycles. IGF-I Generation Tests were used as a probe to stimulate IGF-I release and were completed during the pre-intervention and intervention phases. Serum IGF-I and PINP were measured during both IGF-I Generation Tests. The study was registered at ClinicalTrials.gov (NCT02367833). Results: Compared to the pre-intervention phase, peak IGF-I concentration in response to the IGF-I Generation Test in the intervention phase was suppressed in the COC group (p < 0.001), but not the CVR or Control groups (p > 0.090). Additionally, compared to the pre-intervention phase, PINP AUC during the intervention phase was suppressed in both COC and CVR groups (p < 0.001), while no difference was observed in the control group (p = 0.980). Conclusion: These data suggest that changes in recombinant human GH-stimulated hepatic IGF-I synthesis in response to combined hormonal contraception (CHC) use are dependent on route of CHC administration, while the influence on PINP is route-independent. Future research is needed to expand these results with larger randomized control trials in all age ranges of women who utilize hormonal contraception. Clinical Trial Registration: www.ClinicalTrials.gov registration NCT02367833.

What Is the Evidence Base for a Potassium Requirement?

Increased intake of potassium should be promoted to reduce the risk of cardiovascular disease and stroke and to protect against bone loss, but confidence in recommended intakes depends on the strength of the evidence. All public health recommendations are considerably higher than current average intakes. Evidence on which current potassium intake recommendations for the United States, Europe, and globally have limitations. More recent evidence reviewed by the Agency for Healthcare Research and Quality affirms that more evidence is needed to define specific values for optimal potassium intakes. Potassium requirements undoubtedly vary with a number of factors including energy needs, race, and intake of sodium.

Potassium Intake, Bioavailability, Hypertension, and Glucose Control.

Potassium is an essential nutrient. It is the most abundant cation in intracellular fluid where it plays a key role in maintaining cell function. The gradient of potassium across the cell membrane determines cellular membrane potential, which is maintained in large part by the ubiquitous ion channel the sodium-potassium (Na+-K+) ATPase pump. Approximately 90% of potassium consumed (60-100 mEq) is lost in the urine, with the other 10% excreted in the stool, and a very small amount lost in sweat. Little is known about the bioavailability of potassium, especially from dietary sources. Less is understood on how bioavailability may affect health outcomes. Hypertension (HTN) is the leading cause of cardiovascular disease (CVD) and a major financial burden ($50.6 billion) to the US public health system, and has a significant impact on all-cause morbidity and mortality worldwide. The relationship between increased potassium supplementation and a decrease in HTN is relatively well understood, but the effect of increased potassium intake from dietary sources on blood pressure overall is less clear. In addition, treatment options for hypertensive individuals (e.g., thiazide diuretics) may further compound chronic disease risk via impairments in potassium utilization and glucose control. Understanding potassium bioavailability from various sources may help to reveal how specific compounds and tissues influence potassium movement, and further the understanding of its role in health.

Assessment of stress levels among cats in four animal shelters.

OBJECTIVE: To measure stress levels among cats in traditional and enriched shelter environments via behavioral assessment and urine cortisol-to-creatinine ratios. DESIGN: Cross-sectional observational study. ANIMALS: 120 cats in 4 Boston-area animal shelters. PROCEDURE: Cats were randomly selected and observed during 3 periods (morning, midday, and afternoon) of 1 day and scored by use of a behavioral assessment scale. The next day, urine samples were collected for analysis of the urine cortisol-to-creatinine ratio. Information about each cat's background before entering the shelter was collected. RESULTS: Stress scores were highest in the morning. The relationships between the amount of time cats spent in the shelter and the cat stress score or urine cortisol-to-creatinine ratio were not strong. There was no correlation between the cat stress score and urine cortisol-to-creatinine ratio. Urine cortisol-to-creatinine ratios did correlate with signs of systemic disease and were significantly lower in cats in the more environmentally enriched shelters, compared with cats in the traditional shelters. Urine cortisol-to-creatinine ratio was highest among cats with high exposure to dogs. Of the cats in the study, 25% had subclinical hematuria detectable on a urine dipstick. CONCLUSIONS AND CLINICAL RELEVANCE: In this study, the cat stress score was not a useful instrument for measuring stress because it failed to identify cats with feigned sleep and high stress levels. Urine cortisol-to-creatinine ratios can be monitored to noninvasively assess stress levels in confined cats. Environmental enrichment strategies may help improve the welfare of cats in animal shelters.

Neutropenia associated with vincristine and L-asparaginase induction chemotherapy for canine lymphoma.

Vincristine (VCR) and L-asparaginase (L-ASP) are commonly used to treat canine lymphoma. As single agents, these drugs are not myelosuppressive. However, in combination, VCR and L-ASP cause severe neutropenia in some dogs. It has been recommended that L-ASP be administered 12-24 hours after VCR to minimize toxicity. The purpose of this retrospective study was to determine the prevalence of neutropenia after VCR/L-ASP induction therapy for canine lymphoma and to evaluate risk factors for myelosuppression, especially the interval between VCR and L-ASP administration. Medical records of 147 dogs were reviewed. L-ASP was given 0 (n = 50), 6 (n = 23), 18 (n = 20), or 24 (n = 54) hours after VCR. Forty percent of the dogs were neutropenic 7 days after VCR/L-ASP, and 18% had neutrophil counts of <1,000 cells/microL. The median neutrophil count was 3,712 cells/microL (range 0-30,968 cells/microL). No correlation was found between administration interval and day 7 neutrophil count (P = .84) or development of gastrointestinal signs, including vomiting (P = .80), diarrhea (P = .52), and decreased appetite (P = .30). No significant predictors of neutropenia were identified. Higher clinical stage and substage b were associated with decreased appetite after treatment (P = .04 and .01, respectively). Sixteen percent of the dogs were hospitalized. This study demonstrates that VCR/L-ASP induction for canine lymphoma may result in neutropenia but that separation of VCR and L-ASP administration may not be necessary to avoid toxicity.