Acetaminophen influences musculoskeletal signaling but not adaptations to endurance exercise training

Acetaminophen (ACE) is a widely used analgesic and antipyretic drug with various applications, from pain relief to fever reduction. Recent studies have reported equivocal effects of habitual ACE intake on exercise performance, muscle growth, and risks to bone health. Thus, this study aimed to assess the impact of a 6-week, low-dose ACE regimen on muscle and bone adaptations in exercising and non-exercising rats. Nine-week-old Wistar rats (n = 40) were randomized to an exercise or control (no exercise) condition with ACE or without (placebo). For the exercise condition, rats ran 5 days per week for 6 weeks at a 5% incline for 2 min at 15 cm/s, 2 min at 20 cm/s, and 26 min at 25 cm/s. A human equivalent dose of ACE was administered (379 mg/kg body weight) in drinking water and adjusted each week based on body weight. Food, water intake, and body weight were measured daily. At the beginning of week 6, animals in the exercise group completed a maximal treadmill test. At the end of week 6, rats were euthanized, and muscle cross-sectional area (CSA), fiber type, and signaling pathways were measured. Additionally, three-point bending and microcomputer tomography were measured in the femur. Follow-up experiments in human primary muscle cells were used to explore supra-physiological effects of ACE. Data were analyzed using a two-way ANOVA for treatment (ACE or placebo) and condition (exercise or non-exercise) for all animal outcomes. Data for cell culture experiments were analyzed via ANOVA. If omnibus significance was found in either ANOVA, a post hoc analysis was completed, and a Tukey's adjustment was used. ACE did not alter body weight, water intake, food intake, or treadmill performance (p > .05). There was a treatment-by-condition effect for Young's Modulus where placebo exercise was significantly lower than placebo control (p < .05). There was no treatment by condition effects for microCT measures, muscle CSA, fiber type, or mRNA expression. Phosphorylated-AMPK was significantly increased with exercise (p < .05) and this was attenuated with ACE treatment. Furthermore, phospho-4EBP1 was depressed in the exercise group compared to the control (p < .05) and increased in the ACE control and ACE exercise group compared to placebo exercise (p < .05). A low dose of ACE did not influence chronic musculoskeletal adaptations in exercising rodents but acutely attenuated AMPK phosphorylation and 4EBP1 dephosphorylation post-exercise.

Replacement of dietary carbohydrate with protein increases fat mass and reduces hepatic triglyceride synthesis and content in female obese Zucker rats

Previous studies have demonstrated both energy restriction (ER) and higher protein (HP), lower carbohydrate (LC) diets downregulate hepatic de novo lipogenesis. Little is known about the independent and combined impact of ER and HP/LC diets on tissue-specific lipid kinetics in leptin receptor-deficient, obese rodents. This study investigated the effects of ER and dietary macronutrient content on body composition; hepatic, subcutaneous adipose tissue (SAT), and visceral AT (VAT) lipid metabolic flux (2 H2 O-labeling); and blood and liver measures of cardiometabolic health in six-week-old female obese Zucker rats (Leprfa+/fa+ ). Animals were randomized to a 10-week feeding intervention: ad libitum (AL)-HC/LP (76% carbohydrate/15% protein), AL-HP/LC (35% protein/56% carbohydrate), ER-HC/LP, or ER-HP/LC. ER groups consumed 60% of the feed consumed by AL. AL gained more fat mass than ER (P-energy = 0.012) and HP/LC gained more fat mass than HC/LP (P-diet = 0.025). Hepatic triglyceride (TG) concentrations (P-interaction = 0.0091) and absolute hepatic TG synthesis (P-interaction = 0.012) were lower in ER-HP/LC versus ER-HC/LP. ER had increased hepatic, SAT, and VAT de novo cholesterol fractional synthesis, absolute hepatic cholesterol synthesis, and serum cholesterol (P-energy≤0.0035). A HP/LC diet, independent of energy intake, led to greater gains in fat mass. A HP/LC diet, in the context of ER, led to reductions in absolute hepatic TG synthesis and TG content. However, ER worsened cholesterol metabolism. Increased adipose tissue TG retention with the HP/LC diet may reflect improved lipid storage capacity and be beneficial in this genetic model of obesity.

Contact time has limited impact on the efficacy of disinfectant towelettes when tested under conditions reflective of realistic use

BACKGROUND

Disinfectant towelettes are increasingly being used as a means to prevent transmission of clinically important pathogens which could lead to healthcare-associated infections (HAIs). However, the efficacy of disinfectant towelette products when tested under realistic use conditions is understudied. A test model was designed to replicate realistic wiping conditions. The objective of this study was to determine the impact of varied contact time on disinfectant towelette efficacy under these conditions.

METHODS

Five product types were tested against Staphylococcus aureus (ATCC 6538) and Pseudomonas aeruginosa (ATCC 15,442) at five contact times (30 s, one min, two min, three min, and 10 min) on hard, non-porous laminate templates to determine the impact of contact time on disinfectant towelette efficacy when tested under realistic use.

RESULTS

Product type had a significant impact on the efficacy of disinfectant towelettes when tested under conditions reflective of realistic use. The effect of contact time was limited and no differences in efficacy were seen at a contact time of one min compared with the other contact times tested. Only one disinfectant towelette product achieved a mean 5-log reduction under the tested conditions.

CONCLUSION

Efficacy of disinfectant towelettes was primarily impacted by product type when applied in a model designed to replicate realistic use in which only a limited effect of contact time was observed. There is a need for further investigation into which factors have the greatest impact on disinfectant towelette efficacy when applied in clinical settings.

Contact time and disinfectant formulation significantly impact the efficacies of disinfectant towelettes against Candida auris on hard, non-porous surfaces

There has been an increase in Candida auris healthcare-associated infections, which result from cross-contamination from surfaces and equipment. In this study, we tested the efficacies of EPA-registered disinfectant towelettes products that are increasingly used for infection control against C. auris at a range of contact times following modifications to standard EPA protocol MB-33-00. Hydrogen peroxide (HP)-based disinfectant towelettes were more efficacious against C. auris than the quaternary ammonium chloride (QAC)-alcohol-based disinfectant towelettes irrespective of tested contact times. Thirty s contact time was significantly less effective in reducing C. auris compared to 1-, 2-, 3-, and 10-min contact times. However, there were no statistically significant differences in the level of disinfection among 1-min and longer contact times regardless of product chemistry. None of the products achieved a standard six-log₁₀ reduction at any tested contact times. Overall, the HP-based disinfectant towelette was significantly more fungicidal than the QAC-alcohol-based disinfectant towelette. For all product types, 30 s contact time did not achieve the same level of disinfection as 1-min or longer contact times. Overall, disinfectant towelette efficacy is dependent upon product formulation and contact time.

Slc39a4 in the small intestine predicts zinc absorption and utilization: a comprehensive analysis of zinc transporter expression in response to diets of varied zinc content in young mice

Zinc homeostasis is primarily maintained by zinc transporters that regulate zinc uptake and efflux in the small intestine; however, the relative contribution of the many zinc transporters identified (Slc39a1-14, Slc30a1-10) to dietary zinc absorption and utilization remains unknown. The objective of this study was to determine the expression of Slc39a1-14 and Slc30a1-10 in the small intestine and their relative contribution to dietary zinc absorption in mice. Five-week-old male C57BL/6J mice were fed modified AIN-93G diets containing <1, 30, or 100ppm zinc (n=15 mice/diet). Following 1 week of feeding, mice were given an oral gavage containing ⁶⁷Zn and liver and plasma isotope appearance was determined 6-h later by ICP-MS. Expression of Slc39a1-14 and Slc30a1-10 was determined in mucosa from duodenum, jejunum, and ileum. Plasma and liver total zinc concentrations were not different after one week of feeding (P>.05). Liver and plasma appearance of ⁶⁷Zn was greater in mice fed <1ppm compared to the 30ppm (P<.0001) and 100ppm (P<.0001) zinc diets. With the exception of Slc39a2, Slc39a12, Slc30a3, and Slc30a8, the remaining zinc transporters were expressed across all diets and intestinal segments. Expression of Slc39a4, Slc39a11, and Slc30a6 changed with diet (P_diet<.05 for all); expression of Slc39a5, Slc39a7, Slc39a11, Slc39a14, Slc30a1, Slc30a2, Slc30a4, Slc30a5, Slc30a7, and Slc30a10 changed by intestinal segment (P_segment<.05 for all). Slc39a4 was the only transporter positively associated with liver (r²=0.316, P<.001) and plasma (r²=0.189, P<.01) ⁶⁷Zn appearance. Although most zinc transporters are expressed in the small intestine, intestinal Slc39a4 predicts fractional zinc absorption and utilization in young mice.

High-Altitude Acclimatization Suppresses Hepcidin Expression During Severe Energy Deficit

Hennigar, Stephen R., Claire E. Berryman, Alyssa M. Kelley, Bradley J. Anderson, Andrew J. Young, James P. McClung, and Stefan M. Pasiakos. High-altitude acclimatization suppresses hepcidin expression during severe energy deficit. High Alt Med Biol. 21:232-236, 2020. Background: The erythropoietic cells in the bone marrow require iron to synthesize heme for incorporation into hemoglobin. Exposure to hypoxic conditions, such as extended sojourns to high altitude (HA), results in increased erythropoiesis and an increased physiological requirement for iron. In addition to increasing iron requirements, hypoxic conditions suppress appetite and often lead to decreased energy intake. The objective of this study was to determine the combined effects of severe energy deficit and hypoxia on hepcidin and measures of iron status in lowlanders sojourning to HA. Methods: Iron status indicators and hepcidin were determined in 17 healthy male volunteers (mean ± standard deviation, age 23 ± 6 years, body mass index 27 ± 4 kg/m²) fed a controlled diet (12 ± 1.2 mg iron/day) during a 20-day sojourn to 4300 m above sea level. Results: Chronic exposure to HA during severe energy deficit increased hematocrit by 12% (p < 0.01) and decreased serum hepcidin by 37% (p < 0.01) compared with baseline. Ferritin declined by 18% (p = 0.02) and transferrin saturation and soluble transferrin receptor increased by 55% and 83%, respectively (p < 0.01 for both) compared with baseline. Conclusions: HA acclimatization suppresses hepcidin expression to increase iron availability during severe energy deficit. Registered at ClinicalTrials.gov as NCT02731066.

Metallothionein and Zinc Transporter Expression in Circulating Human Blood Cells as Biomarkers of Zinc Status: a Systematic Review

Zinc is an essential nutrient for humans; however, a sensitive biomarker to assess zinc status has not been identified. The objective of this systematic review was to compile and assess studies that determined zinc transporter and/or metallothionein expression in various blood cell types and to determine their reliability and sensitivity to changes in dietary zinc. Sixteen studies were identified that determined the expression of zrt-, irt-like protein (ZIP) 1 [solute carrier family (SLC) 39A1], ZIP3 (SLC39A3), ZIP5 (SLC39A5), ZIP6 (SLC39A6), ZIP7 (SLC39A7), ZIP8 (SLC39A8), ZIP10 (SLC39A10), ZIP14 (SLC39A14), zinc transporter (ZnT)1 (SLC30A1), ZnT2 (SLC30A2), ZnT4 (SLC30A4), ZnT5 (SLC30A5), ZnT6 (SLC30A6), ZnT7 (SLC30A7), ZnT9 (SLC30A9), and/or metallothionein in various blood cells isolated from healthy adult men and women in response to zinc supplementation or depletion. Cell types included leukocytes, peripheral blood mononuclear cells, T lymphocytes, monocytes, and erythrocytes. ZIP1, ZnT1, and metallothionein were the most commonly measured proteins. Changes in ZIP1 and ZnT1 in response to zinc supplementation or depletion were not consistent across studies. Leukocyte metallothionein decreased with zinc depletion (-39% change from baseline, <5 mg Zn/d, n = 2 studies) and increased with zinc supplementation in a dose-dependent manner (35%, 15-22 mg Zn/d, n = 7 studies; 267%, 50 mg Zn/d, n = 2 studies) and at the earliest time points measured; however, no change or delayed response was observed in metallothionein in erythrocytes. A greater percentage of studies demonstrated that metallothionein in leukocyte subtypes was a more reliable (100%, n = 12; 69%, n = 16) and responsive (92%, n = 12; 82%, n = 11) indicator of zinc exposure than was plasma zinc, respectively. In conclusion, current evidence indicates that metallothionein in leukocyte subtypes may be a component in determining zinc status.

Factor structure of a measure of anxiety sensitivity in children

Anxiety sensitivity (i.e., the disposition to react to autonomic arousal with fear) has taken a central role in recent conceptualizations of anxiety. However, questions regarding the dimensional nature of anxiety sensitivity remain. In particular, the factor structure of anxiety sensitivity is unexplored in nonadult populations. The factor structure of the Anxiety Sensitivity Index for Children (ASIC) was examined in three studies. Study 1 (N = 95) used a sample of school children in Grades 4-8 to investigate the reliability of items and factor structure. Items with weak psychometric properties were eliminated, and subsequent analyses revealed that the ASIC was best viewed as a hierarchical scale with a higher order factor (Anxiety Sensitivity) and two first-order factors (Fear of Physiological Arousal and Fear of Mental Catastrophe). Study 2 (N = 112) and Study 3 (N = 144) used more distressed samples of youngsters, and they also found the ASIC to be a hierarchical scale. These findings add a developmental perspective to the Anxiety Sensitivity Index factor analytic discussion and are highly consistent with emergent thinking in the adult anxiety sensitivity literature.