Creatinine clearance is maintained in a range of wet-bulb globe temperatures and work-rest ratios during simulated occupational heat stress.

We tested the hypothesis that compliance with the National Institute for Occupational Safety and Health (NIOSH) heat stress recommendations will prevent reductions in glomerular filtration rate (GFR) across a range of wet-bulb globe temperatures (WBGTs) and work-rest ratios at a fixed work intensity. We also tested the hypothesis that noncompliance would result in a reduction in GFR compared with a work-rest matched compliant trial. Twelve healthy adults completed five trials (four NIOSH compliant and one noncompliant) that consisted of 4 h of exposure to a range of WBGTs. Subjects walked on a treadmill (heat production: approximately 430 W) and work-rest ratios (work/h: 60, 45, 30, and 15 min) were prescribed as a function of WBGT (24°C, 26.5°C, 28.5°C, 30°C, and 36°C), and subjects drank a sport drink ad libitum. Peak core temperature (TC) and percentage change in body weight (%ΔBW) were measured. Creatinine clearance measured pre- and postexposure provided a primary marker of GFR. Peak TC did not differ among NIOSH-compliant trials (P = 0.065) but differed between compliant versus noncompliant trials (P < 0.001). %ΔBW did not differ among NIOSH-compliant trials (P = 0.131) or between compliant versus noncompliant trials (P = 0.185). Creatinine clearance did not change or differ among compliant trials (P ≥ 0.079). Creatinine clearance did not change or differ between compliant versus noncompliant trials (P ≥ 0.661). Compliance with the NIOSH recommendations maintained GFR. Surprisingly, despite a greater heat strain in a noncompliant trial, GFR was maintained highlighting the potential relative importance of hydration.NEW & NOTEWORTHY We highlight that glomerular filtration rate (GFR) is maintained during simulated occupational heat stress across a range of total work, work-rest ratios, and wet-bulb globe temperatures with ad libitum consumption of an electrolyte and sugar-containing sports drink. Compared with a work-rest matched compliant trial, noncompliance resulted in augmented heat strain but did not induce a reduction in GFR likely due to an increased relative fluid intake and robust fluid conservatory responses.

Renal vascular control during normothermia and passive heat stress does not differ between healthy younger men and women.

Men are likely at greater risk for heat-induced acute kidney injury compared with women, possibly due to differences in vascular control. We tested the hypothesis that the renal vasoconstrictor and vasodilator responses will be greater in younger women compared with men during passive heat stress. Twenty-five healthy adults [12 women (early follicular phase) and 13 men] completed two experimental visits, heat stress or normothermic time-control, assigned in a block-randomized crossover design. During heat stress, participants wore a water-perfused suit perfused with 50°C water. Core temperature was increased by ∼0.8°C in the first hour before commencing a 2-min cold pressor test (CPT). Core temperature remained clamped and at 1-h post-CPT, subjects ingested a whey protein shake (1.2 g of protein/kg body wt), and measurements were taken pre-, 75 min, and 150 min post-protein. Beat-to-beat blood pressure (Penaz method) was measured and segmental artery vascular resistance (VR, Doppler ultrasound) was calculated as segmental artery blood velocity ÷ mean arterial pressure. CPT-induced increases in segmental artery VR did not differ between trials (trial effect: P = 0.142) nor between men (heat stress: 1.5 ± 1.0 mmHg/cm/s, normothermia: 1.4 ± 1.0 mmHg/cm/s) and women (heat stress: 1.4 ± 1.2 mmHg/cm/s, normothermia: 2.1 ± 1.1 mmHg/cm/s) (group effect: P = 0.429). Reductions in segmental artery VR following oral protein loading did not differ between trials (trial effect: P = 0.080) nor between men (heat stress: -0.6 ± 0.8 mmHg/cm/s, normothermia: -0.6 ± 0.6 mmHg/cm/s) and women (heat stress: -0.5 ± 0.5 mmHg/cm/s, normothermia: -1.1 ± 0.6 mmHg/cm/s) (group effect: P = 0.204). Renal vasoconstrictor responses to the cold pressor test and vasodilator responses following an oral protein load during heat stress or normothermia do not differ between younger men and younger women in the early follicular phase of the menstrual cycle.NEW & NOTEWORTHY The mechanisms underlying greater heat-induced acute kidney injury risk in men versus women remain unknown. This study examined renal vascular control, including both vasodilatory (oral protein load) and vasoconstrictor (cold presser test) responses, during normothermia and heat stress and compared these responses between men and women. The results indicated that in both conditions neither renal vasodilatory nor vasoconstrictor responses differ between younger men and younger women.

The independent effects of hydrostatic pressure and hypercapnic breathing during water immersion on ventilatory sensitivity and cerebrovascular reactivity.

Head-out water immersion (HOWI) induces ventilatory and hemodynamic changes, which may be a result of hydrostatic pressure, augmented arterial CO2 tension, or a combination of both. We hypothesized that the hydrostatic pressure and elevated CO2 tension that occur during HOWI will contribute to an augmented ventilatory sensitivity to CO2 and an attenuated cerebrovascular reactivity to CO2 during water immersion. Twelve subjects [age: 24 ± 3 yr, body mass index (BMI): 25 ± 3 kg/m2] completed HOWI, waist water immersion with CO2 (WWI + CO2), and WWI, where a rebreathing test was conducted at baseline, 10, 30, and 60 min, and postimmersion. End-tidal pressure of carbon dioxide ([Formula: see text]), minute ventilation, expired gases, blood pressure, heart rate, and middle cerebral artery blood velocity were recorded continuously. [Formula: see text] increased throughout all visits (P ≤ 0.011), was similar during HOWI and WWI + CO2 (P ≥ 0.264), and was greater during WWI + CO2 versus WWI at 10, 30, and 60 min (P < 0.001). When HOWI vs. WWI + CO2 were compared, the change in ventilatory sensitivity to CO2 was different at 10 (0.59 ± 0.34 vs. 0.06 ± 0.23 L/min/mmHg; P < 0.001), 30 (0.58 ± 0.46 vs. 0.15 ± 0.25 L/min/mmHg; P < 0.001), and 60 min (0.63 ± 0.45 vs. 0.16 ± 0.34 L/min/mmHg; P < 0.001), whereas there were no differences between conditions for cerebrovascular reactivity to CO2 (P ≥ 0.163). When WWI + CO2 versus WWI were compared, ventilatory sensitivity to CO2 was not different between conditions (P ≥ 0.642), whereas the change in cerebrovascular reactivity to CO2 was different at 30 min (-0.56 ± 0.38 vs. -0.30 ± 0.25 cm/s/mmHg; P = 0.010). These data indicate that during HOWI, ventilatory sensitivity to CO2 increases due to the hydrostatic pressure, whereas cerebrovascular reactivity to CO2 decreases due to the combined effects of immersion.NEW & NOTEWORTHY Although not fully elucidated, the ventilatory and hemodynamic alterations during water immersion appear to be a result of the combined effects of immersion (i.e., elevated [Formula: see text], central hypervolemia, increased cerebral perfusion, increased work of breathing, etc.). Our findings demonstrate that an augmented ventilatory sensitivity to CO2 during immersion may be due to the hydrostatic pressure across the chest wall, whereas an attenuated cerebrovascular reactivity to CO2 may be due to the combined effects of immersion.

Activation of cardiac parasympathetic and sympathetic activity occurs at different skin temperatures during face cooling.

Sufficiently cold-water temperatures (<7°C) are needed to elicit the sympathetic response to the cold pressor test using the hand. However, it is not known if stimulating the trigeminal nerve via face cooling, which increases both sympathetic and cardiac parasympathetic activity, also has a threshold temperature. We tested the hypothesis that peak autonomic activation during a progressive face cooling challenge would be achieved when the stimulus temperature is ≤7°C. Twelve healthy participants (age: 25 ± 3 yr, four women) completed our study. Six pliable bags, each containing water or an ice slurry (34°C, 28°C, 21°C, 14°C, 7°C, and 0°C) were applied sequentially to participants' forehead, eyes, and cheeks for 5 min each. Mean arterial pressure (photoplethysmography; index of sympathetic activity) and heart rhythm (3-lead ECG) were averaged in 1-min increments at the end of baseline and throughout each temperature condition. Heart rate variability in the time [(root mean square of successive differences (RMSSD)] and frequency [high-frequency (HF) power] domains was used to estimate cardiac parasympathetic activity. Data are presented as the increase from baseline ± SD. Mean arterial pressure only increased from baseline in the 7°C (13.1 ± 10.3 mmHg; P = 0.018) and 0°C (25.2 ± 7.8 mmHg; P < 0.001) conditions. Only the 0°C condition increased RMSSD (160.6 ± 208.9 ms; P = 0.009) and HF power (11,450 ± 14,555 ms2; P = 0.014) from baseline. Our data indicate that peak increases in sympathetic activity during face cooling are initiated at a higher forehead skin temperature than peak increases in cardiac parasympathetic activity.

Relation between resting spleen volume and apnea-induced increases in hemoglobin mass.

Introduction: Indigenous populations renowned for apneic diving have comparatively large spleen volumes. It has been proposed that a larger spleen translates to heightened apnea-induced splenic contraction and elevations in circulating hemoglobin mass (Hbmass), which, in theory, improves O2 carrying and/or CO2/pH buffering capacities. However, the relation between resting spleen volume and apnea- induced increases in Hbmass is unknown. Therefore, we tested the hypothesis that resting spleen volume is positively related to apnea-induced increases in total Hbmass. Methods: Fourteen healthy adults (six women; 29 ± 5 years) completed a two-minute carbon monoxide rebreathe procedure to measure pre-apneas Hbmass and blood volume. Spleen length, width, and thickness were measured pre-and post-five maximal apneas via ultrasound. Spleen volume was calculated via the Pilström equation (test-retest CV:2 ± 2%). Hemoglobin concentration ([Hb]; g/dl) and hematocrit (%) were measured pre- and post-apneas via capillary blood samples. Post-apneas Hbmass was estimated as post-apnea [Hb] x pre-apnea blood volume. Data are presented as mean ± SD. Results: Spleen volume decreased from pre- (247 ± 95 mL) to post- (200 ± 82 mL, p<0.01) apneas. [Hb] (14.6 ± 1.2 vs. 14.9 ± 1.2 g/dL, p<0.01), hematocrit (44 ± 3 vs. 45 ± 3%, p=0.04), and Hbmass (1025 ± 322 vs. 1046 ± 339 g, p=0.03) increased from pre- to post-apneas. Pre-apneas spleen volume was unrelated to post-apneas increases in Hbmass (r=-0.02, p=0.47). O2 (+28 ± 31 mL, p<0.01) and CO2 (+31 ± 35 mL, p<0.01) carrying capacities increased post-apneas. Conclusion: Larger spleen volume is not associated with a greater rise in apneas-induced increases in Hbmass in non-apnea-trained healthy adults.

Diagnostic accuracy of thermal, hydration, and heart rate assessments in discriminating positive acute kidney injury risk following physical work in the heat.

Occupational heat stress increases the risk of acute kidney injury (AKI). This study presents a secondary analysis to generate novel hypotheses for future studies by investigating the diagnostic accuracy of thermal, hydration, and heart rate assessments in discriminating positive AKI risk following physical work in the heat in unacclimatized individuals. Unacclimatized participants (n = 13, 3 women, age: ∼23 years) completed four trials involving 2 h of exercise in a 39.7 ± 0.6 °C, 32 ± 3% relative humidity environment that differed by experimental manipulation of hyperthermia (i.e., cooling intervention) and dehydration (i.e., water drinking). Diagnostic accuracy was assessed via receiver operating characteristic curve analysis. Positive AKI risk was identified when the product of concentrations insulin-like growth factor binding protein 7 and tissue inhibitor of metalloproteinase-2 [IGFBP7∙TIMP-2] exceeded 0.3 (ng∙mL-1)2∙1000-1. Peak absolute core temperature had the acceptable discriminatory ability (AUC = 0.71, p = 0.009), but a relatively large variance (AUC 95% CI: 0.57-0.86). Mean body temperature, urine specific gravity, urine osmolality, peak heart rate, and the peak percent of both maximum heart rate and heart rate reserve had poor discrimination (AUC = 0.66-0.69, p ≤ 0.051). Mean skin temperature, percent change in body mass and plasma volume, and serum sodium and osmolality had no discrimination (p ≥ 0.072). A peak increase in mean skin temperature of >4.7 °C had a positive likelihood ratio of 11.0 which suggests clinical significance. These data suggest that the absolute value of peak core temperature and the increase in mean skin temperature may be valuable to pursue in future studies as a biomarker for AKI risk in unacclimatized workers.

A draft Diabrotica virgifera virgifera genome: insights into control and host plant adaption by a major maize pest insect.

BACKGROUND: Adaptations by arthropod pests to host plant defenses of crops determine their impacts on agricultural production. The larval host range of western corn rootworm, Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae), is restricted to maize and a few grasses. Resistance of D. v. virgifera to crop rotation practices and multiple insecticides contributes to its status as the most damaging pest of cultivated maize in North America and Europe. The extent to which adaptations by this pest contributes to host plant specialization remains unknown. RESULTS: A 2.42 Gb draft D. v. virgifera genome, Dvir_v2.0, was assembled from short shotgun reads and scaffolded using long-insert mate-pair, transcriptome and linked read data. K-mer analysis predicted a repeat content of ≥ 61.5%. Ortholog assignments for Dvir_2.0 RefSeq models predict a greater number of species-specific gene duplications, including expansions in ATP binding cassette transporter and chemosensory gene families, than in other Coleoptera. A majority of annotated D. v. virgifera cytochrome P450s belong to CYP4, 6, and 9 clades. A total of 5,404 transcripts were differentially-expressed between D. v. virgifera larvae fed maize roots compared to alternative host (Miscanthus), a marginal host (Panicum virgatum), a poor host (Sorghum bicolor) and starvation treatments; Among differentially-expressed transcripts, 1,908 were shared across treatments and the least number were between Miscanthus compared to maize. Differentially-expressed transcripts were enriched for putative spliceosome, proteosome, and intracellular transport functions. General stress pathway functions were unique and enriched among up-regulated transcripts in marginal host, poor host, and starvation responses compared to responses on primary (maize) and alternate hosts. CONCLUSIONS: Manual annotation of D. v. virgifera Dvir_2.0 RefSeq models predicted expansion of paralogs with gene families putatively involved in insecticide resistance and chemosensory perception. Our study also suggests that adaptations of D. v. virgifera larvae to feeding on an alternate host plant invoke fewer transcriptional changes compared to marginal or poor hosts. The shared up-regulation of stress response pathways between marginal host and poor host, and starvation treatments may reflect nutrient deprivation. This study provides insight into transcriptomic responses of larval feeding on different host plants and resources for genomic research on this economically significant pest of maize.

Salivary Cortisol Dynamics After Mild Traumatic Brain Injury.

OBJECTIVE: To assess mild traumatic brain injury (mTBI)-related alterations in baseline (resting) salivary cortisol and cortisol reactivity to cognitive and exercise stressors, which are frequently encountered during mTBI rehabilitation and recovery. SETTING: Persons with mTBI were recruited from a level 1 trauma center emergency department. Uninjured controls (UCs) were recruited from the community. PARTICIPANTS: Participants were 37 individuals with mTBI and 24 UCs. All patients with mTBI were enrolled at 7 ± 3 days post-injury, met the American Congress of Rehabilitation Medicine definition of mTBI, and had no acute intracranial findings on clinical neuroimaging (if performed). DESIGN: A prospective cohort study design was used. All participants provided saliva samples 10 times during each of 2 visits spaced 3 weeks apart (1 week and 1 month post-injury for the mTBI group). Each visit included baseline saliva sampling and sampling to evaluate reactivity to a cognitive stressor (Paced Auditory Serial Addition Test) and physical stressor (Buffalo Concussion Treadmill Test [BCTT]). MAIN OUTCOME MEASURE: Natural log-transformed salivary cortisol was measured by enzyme immunoassay. Cortisol was predicted using a linear mixed-effects model by group (mTBI and UC), visit (1 week and 1 month), and saliva sample. RESULTS: Mean salivary cortisol was higher in the mTBI group (1.67 nmol/L [95% CI 1.42-1.72]) than in controls (1.30 nmol/L [1.12-1.47]), without an mTBI × time interaction. At 1 week, the mTBI group had greater cortisol reactivity in response to the BCTT. CONCLUSIONS: Higher cortisol in individuals with mTBI at 1 week and 1 month post-injury extends previous findings into the subacute recovery period. Furthermore, the mTBI group demonstrated a greater cortisol response to mild-to-moderate aerobic exercise (BCTT) at 1 week post-injury. Given the increasing role of exercise in mTBI rehabilitation, further research is warranted to replicate these findings and identify the clinical implications, if any, of enhanced hypothalamic-pituitary-adrenal axis responses to exercise in civilians with recent mTBI.

Aerobic exercise performance is reduced following prolonged cold-water immersion.

Background: We tested the hypotheses that self-paced aerobic exercise performance is reduced following four hours of cold-water immersion when breathing air and further reduced when breathing 100% oxygen (O2). Nine healthy adults (four women; age 24 ± 3 years; body fat 17.9 ± 6.4%; VO2max 48±9 mL • kg • minute⁻¹) completed three visits: a no-immersion control trial and two experimental trials consisting of a four-hour cold-water immersion (20.1±0.3°C) either breathing air (FIO2 = 0.21) or O2 (FIO2 = 1.0). During the no-immersion control trial and following immersion in the experimental trials, subjects first completed a 60-minute ruck-march carrying 20% of body mass in a rucksack, immediately followed by an unweighted, self-paced 5-km time trial on a motorized treadmill. Core temperature, heart rate, and rating of perceived exertion were recorded every 1,000 meters during the 5-km time trial. Data are presented mean± SD. Time trial performance was reduced following immersion in both the 100% O2 trial (32±6 minutes; p=0.01) and air trial (32±5 minutes; p=0.01) compared to the control trial (28± 4 minutes). However, there was no difference between the 100% O2 and air trials (p=0.86). Heart rate, core temperature, and rating of perceived exertion increased during the time trial (time effect: p≺0.01), but were not different between trials (trial effect: p≥0.33). These findings suggest that prolonged cold-water immersion attenuates self-paced aerobic exercise performance, but does not appear to be further affected by breathing gas type.

Water consumption patterns impact hydration markers in males working in accordance with the National Institute for Occupational Safety and Health recommendations.

The impact of water consumption bolus volume and frequency on hydration biomarkers during work in the heat is unknown. In a randomized, crossover fashion, eight males consumed either 500 mL of water every 40 min or 237 mL of water every 20 min during 2 hr of continuous walking at 6.4 kph, 1.0% grade in a 34 °C/30% relative humidity environment, followed by 2 hr of rest. Hydration biomarkers and variables were assessed pre-work, post-work, and after the 2 hr recovery. There were no differences in body mass between trials at any time point (all p > 0.05). Percent change in plasma volume during work was not different when 237 mL of water was repeatedly consumed (-1.6 ± 8.2%) compared to 500 mL of water (-1.3 ± 3.0%, p = 0.92). Plasma osmolality was maintained over time (p = 0.55) with no difference between treatments (p = 0.21). When consuming 500 mL of water repeatedly, urine osmolality was lower at recovery (205 ± 108 mOsmo/L) compared to pre-work (589 ± 95 mOsmo/L, p < 0.01), different from repeatedly consuming 237 mL of water which maintained urine osmolality from pre-work (548 ± 144 mOsmo/L) through recovery (364 ± 261 mOsmo/L, p = 0.14). Free water clearance at recovery was greater with repeated consumption of 500 mL of water (1.2 ± 1.0 mL/min) compared to 237 mL of water (0.4 ± 0.8 mL/min, p = 0.02). Urine volume was not different between treatments post-work (p = 0.62), but greater after 2 hr of recovery when repeatedly consuming 500 mL of water compared to 237 mL (p = 0.01), leading to greater hydration efficiency upon recovery with repeated consumption of 237 mL of water (68 ± 12%) compared to 500 mL (63 ± 14%, p = 0.01). Thirst and total gastrointestinal symptom scores were not different between treatments at any time point (all p > 0.05). Body temperatures and heart rate were not different between treatments at any time point (all p > 0.05). Drinking larger, less frequent water boluses or drinking smaller, more frequent water boluses are both reasonable strategies to promote adequate hydration and limit changes in body mass in males completing heavy-intensity work in the heat.

Glomerular filtration rate reserve is reduced during mild passive heat stress in healthy young adults.

We tested the hypothesis that, compared with normothermia, the increase in glomerular filtration rate (GFR) after an oral protein load (defined as the GFR reserve) is attenuated during moderate passive heat stress in young healthy adults. Sixteen participants (5 women; 26 ± 2 yr) completed two experimental visits, heat stress or a normothermic time-control, assigned in a block-randomized crossover design. During the heat stress trial, core temperature was increased by 0.6°C in the first hour before commencing a 2-min cold pressor test (CPT) to assess renal vasoconstrictor responses. One-hour post-CPT, subjects ingested a whey protein shake (1.2 g of protein/kg body wt), and measurements were taken pre-, 75, and 150 min postprotein. Segmental artery vascular resistance was calculated as the quotient of Doppler ultrasound-derived segmental artery blood velocity and mean arterial pressure and provided an estimate of renal vascular tone. GFR was estimated from creatinine clearance. The increase in segmental artery vascular resistance during the CPT was attenuated during heat stress (end CPT: 5.6 ± 0.9 vs. 4.7 ± 1.1 mmHg/cm/s, P = 0.024). However, the reduction in segmental artery vascular resistance in response to an oral protein load did not differ between heat stress (at 150 min: 1.9 ± 0.4 mmHg/cm/s) and normothermia (at 150 min: 1.8 ± 0.5 mmHg/cm/s; P = 0.979). The peak increase in creatinine clearance postprotein, independent of time, was attenuated during heat stress (+26 ± 19 vs. +16 ± 20 mL/min, P = 0.013, n = 13). GFR reserve is diminished by mild passive heat stress. Moreover, renal vasoconstrictor responses are attenuated by mild passive heat stress, but renal vasodilator responses are maintained.

Increased spleen volume provoked by temperate head-out-of-water immersion.

This study tested the hypotheses that 1) spleen volume increases during head-out-of-water immersion (HOWI) and returns to pre-HOWI values postdiuresis, and 2) the magnitude of apnea-induced spleen contraction increases when preapnea spleen volume is elevated. Spleen volume was measured before and after a set of five apneas in 12 healthy adults (28 ± 5 yr, 3 females) before, during (at 30 and 150 min), and 20 min after temperate temperature (36 ± 1°C) HOWI. At each time point, spleen length, width, and thickness were measured via ultrasound, and spleen volume was calculated using the Pilström equation. Compared with pre-HOWI (276 ± 88 mL), spleen volume was elevated at 30 (353 ± 94 mL, P < 0.01) and 150 (322 ± 87 mL, P < 0.01) min of HOWI but returned to pre-HOWI volume at post-HOWI (281 ± 90 mL, P = 0.58). Spleen volume decreased from pre- to postapnea bouts at each time point (P < 0.01). The magnitude of reduction in spleen volume from pre- to postapneas was elevated at 30 min of HOWI (-69 ± 24 mL) compared with pre-HOWI (-52 ± 20 mL, P = 0.04) but did not differ from pre-HOWI at 150 min of HOWI (-54 ± 16 mL, P = 0.99) and post-HOWI (-50 ± 18 mL, P = 0.87). Thus, spleen volume is increased throughout 180 min of HOWI, and whereas apnea-induced spleen contraction is augmented after 30 min of HOWI, the magnitude of spleen contraction is unaffected by HOWI thereafter.

Heterogeneous Synthetic Vesicles toward Artificial Cells: Engineering Structure and Composition of Membranes for Multimodal Functionalities.

The desire to develop artificial cells to imitate living cells in synthetic vesicle platforms has continuously increased over the past few decades. In particular, heterogeneous synthetic vesicles made from two or more building blocks have attracted attention for artificial cell applications based on their multifunctional modules with asymmetric structures. In addition to the traditional liposomes or polymersomes, polypeptides and proteins have recently been highlighted as potential building blocks to construct artificial cells owing to their specific biological functionalities. Incorporating one or more functionally folded, globular protein into synthetic vesicles enables more cell-like functions mediated by proteins. This Review highlights the recent research about synthetic vesicles toward artificial cell models, from traditional synthetic vesicles to protein-assembled vesicles with asymmetric structures. We aim to provide fundamental and practical insights into applying knowledge on molecular self-assembly to the bottom-up construction of artificial cell platforms with heterogeneous building blocks.

Ultrasonographic Inferior Vena Cava Measurement is More Sensitive Than Vital Sign Abnormalities for Identifying Moderate and Severe Hemorrhage.

BACKGROUND: Ultrasound inferior vena cava (IVC) diameter has been shown to decrease in response to hemorrhage. IVC diameter cut points to identify moderate and severe blood loss have not been established. OBJECTIVES: This study sought to find ultrasound IVC diameter cut points to identify moderate and severe hemorrhage and assess the performance of these cut points vs. vital sign abnormalities. METHODS: This is a secondary analysis of data from a study that described changes in vital signs and sonographic measurements of the IVC during a lower body negative pressure model of hemorrhage. Using receiver operator curve analyses, optimal cut points for identifying moderate and severe hemorrhage were identified. The ability of these cut points to identify hemorrhage in patients with no vital sign abnormalities was then assessed. RESULTS: In both long- and short-axis views, maximum and minimum IVC diameters (IVCmax and IVCmin) were significantly lower than baseline in severe blood loss. The optimal cut point for IVCmax in both axes was found to be ≤ 0.8 cm. This cut point is able to distinguish between no blood loss vs. moderate blood loss, and no blood loss vs. severe blood loss. The optimal cut point for IVCmin was variable between axes and blood loss severity. IVC diameter cut points obtained were able to identify hemorrhage in patients with no vital sign abnormalities. CONCLUSION: An ultrasound IVCmax of ≤ 0.8 cm may be useful in identifying moderate and severe hemorrhage before vital sign abnormalities are evident.

Physical symptoms provoked by normobaric hot and humid disabled pressurized rescue module scenarios.

We tested the hypothesis that thermal discomfort will be greater, mood will be worse, and physical symptoms of heat illness will be exacerbated with elevations in dry bulb temperature during exposure to >95% relative humidity disabled pressurized rescue module simulation. On three occasions, 15 healthy males (23 ± 3 years) sat in 32.1 ± 0.1°C, 33.1 ± 0.2°C or 35.0 ± 0.1°C, and 95 ± 2% relative humidity normobaric environments for eight hours. Thermal discomfort (visual analog scale), mood (profile of mood states), and physical symptoms of heat illness, ear-nose-throat, and muscle discomfort (environmental symptoms questionnaire) were assessed before and following each hour of exposure. Thermal discomfort was greater throughout the exposure in 35°C versus both 32°C and 33°C (p ≥ 0.03) and did not differ between the latter conditions (p ≥ 0.07). Mood worsened over time in all trials (p ≺ 0.01) and was worse in 35°C compared to 32°C and 33°C after five hours of exposure (p ≤ 0.05). Heat illness symptoms increased over time in all trials and was greater in 35°C versus 32°C and 33°C throughout the exposure (p ≤ 0.04). Ear-nose-throat and muscle discomfort symptoms increased over time in all trials (p < 0.01) and were higher in 35°C versus 32°C and 33°C after the sixth hour of exposure (p ≤ 0.02). In support of our hypothesis, mood was worse, physical symptoms of heat illness, and ear-nose-throat and muscle discomfort symptoms were exacerbated, and thermal discomfort was greater with elevations in dry bulb temperature during an eight-hour exposure to a >95% relative humidity disabled PRM simulation.

Do the National Institute for Occupational Safety and Health recommendations for working in the heat prevent excessive hyperthermia and body mass loss in unacclimatized males?

The National Institute for Occupational Safety and Health recommendations for work in the heat suggest workers consume 237 mL of water every 15-20 min and allow for continuous work at heavy intensities in hot environments up to 34 °C and 30% relative humidity. The goal was to determine whether the National Institute for Occupational Safety and Health recommendations prevented core temperature from exceeding 38.0 °C and greater than 2% body mass loss during heavy-intensity work in the heat. Eight males consumed 237 mL of water every 20 min during 2 hr of continuous heavy-intensity walking (6.4 kph, 1% grade) in a 34 °C/30% relative humidity environment, in accordance with the National Institute for Occupational Safety and Health recommendations. Projected core temperature and percent body mass loss were calculated for 4 and 8 hr of continuous work. Core temperature rose from baseline (36.8 ± 0.3 °C) to completion of 2 hr of work (38.1 ± 0.6 °C, p < 0.01), with two participants reaching the 38.0 °C threshold. Projected core temperatures remained elevated from baseline (p < 0.01), did not change from 2 to 4 hr (38.1 ± 0.7 °C, p > 0.99) and 4 to 8 hr (38.1 ± 0.8 °C, p > 0.99), respectively, and one participant exceeded 38.0 °C at 4 to 8 hr. There was no change in body mass loss over time (p > 0.99). During 2 hr of continuous heavy-intensity work in the heat, 75% of participants did not reach 38 °C core temperature and 88% did not reach 2% body mass loss when working to National Institute for Occupational Safety and Health recommendations.

Molecular identification of trematode parasites infecting the freshwater snail Bithynia siamensis goniomphalos in Thailand.

Digenetic trematodes are important parasites of humans and animals. They have complex life cycles and typically infect a gastropod as the first intermediate host. Bithynia siamensis goniomphalos, the first intermediate host of the liver fluke, Opisthorchis viverrini, harbours a wide variety of other trematode species. Morphological details of cercariae of 20 trematode taxa from B. s. goniomphalos, collected mainly in Thailand from 2009 to 2014, were provided in an earlier paper. Correct identification to the species or genus level based on morphology of these cercariae is generally not possible. Therefore, we used molecular data to improve identification and to investigate the diversity of the species of trematodes infecting B. s. goniomphalos. We were successful in extracting, amplifying and sequencing portions of the 28S ribosomal RNA (rRNA) gene for 19 of these 20 types of cercaria, and the internal transcribed spacer 2 region for 18 types. BLAST searches in GenBank and phylogenetic trees inferred from the 28S rRNA sequences identified members of at least nine superfamilies and 12 families. Only a few cercariae could be assigned confidently to genus or species on the basis of the sequence data. Matching sequence data from named adult trematodes will be required for definitive identification. There is clearly a great diversity of trematode species utilizing B. s. goniomphalos in Thailand.

Up-regulation of apoptotic- and cell survival-related gene pathways following exposures of western corn rootworm to B. thuringiensis crystalline pesticidal proteins in transgenic maize roots.

BACKGROUND: Resistance of pest insect species to insecticides, including B. thuringiensis (Bt) pesticidal proteins expressed by transgenic plants, is a threat to global food security. Despite the western corn rootworm, Diabrotica virgifera virgifera, being a major pest of maize and having populations showing increasing levels of resistance to hybrids expressing Bt pesticidal proteins, the cell mechanisms leading to mortality are not fully understood. RESULTS: Twenty unique RNA-seq libraries from the Bt susceptible D. v. virgifera inbred line Ped12, representing all growth stages and a range of different adult and larval exposures, were assembled into a reference transcriptome. Ten-day exposures of Ped12 larvae to transgenic Bt Cry3Bb1 and Gpp34/Tpp35Ab1 maize roots showed significant differential expression of 1055 and 1374 transcripts, respectively, compared to cohorts on non-Bt maize. Among these, 696 were differentially expressed in both Cry3Bb1 and Gpp34/Tpp35Ab1 maize exposures. Differentially-expressed transcripts encoded protein domains putatively involved in detoxification, metabolism, binding, and transport, were, in part, shared among transcripts that changed significantly following exposures to the entomopathogens Heterorhabditis bacteriophora and Metarhizium anisopliae. Differentially expressed transcripts in common between Bt and entomopathogen treatments encode proteins in general stress response pathways, including putative Bt binding receptors from the ATP binding cassette transporter superfamily. Putative caspases, pro- and anti-apoptotic factors, as well as endoplasmic reticulum (ER) stress-response factors were identified among transcripts uniquely up-regulated following exposure to either Bt protein. CONCLUSIONS: Our study suggests that the up-regulation of genes involved in ER stress management and apoptotic progression may be important in determining cell fate following exposure of susceptible D. v. virgifera larvae to Bt maize roots. This study provides novel insights into insect response to Bt intoxication, and a possible framework for future investigations of resistance mechanisms.

Carotid body chemosensitivity is not attenuated during cold water diving.

Tonic carotid body (CB) activity is reduced during exposure to cold and hyperoxia. We tested the hypotheses that cold water diving lowers CB chemosensitivity and augments CO2 retention more than thermoneutral diving. Thirteen subjects [age: 26 ± 4 yr; body mass index (BMI): 26 ± 2 kg/m2) completed two 4-h head-out water immersion protocols in a hyperbaric chamber (1.6 ATA) in cold (15°C) and thermoneutral (25°C) water. CB chemosensitivity was assessed with brief hypercapnic ventilatory response ([Formula: see text]) and hypoxic ventilatory response ([Formula: see text]) tests before dive, 80 and 160 min into the dive (D80 and D160, respectively), and immediately after and 60 min after dive. Data are reported as an absolute mean (SD) change from predive. End-tidal CO2 pressure increased during both the thermoneutral water dive [D160: +2 (3) mmHg; P = 0.02] and the cold water dive [D160: +1 (2) mmHg; P = 0.03]. Ventilation increased during the cold water dive [D80: 4.13 (4.38) and D160: 7.75 (5.23) L·min-1; both P < 0.01] and was greater than the thermoneutral water dive at both time points (both P < 0.01). [Formula: see text] was unchanged during the dive (P = 0.24) and was not different between conditions (P = 0.23). [Formula: see text] decreased during the thermoneutral water dive [D80: -3.45 (3.61) and D160: -2.76 (4.04) L·min·mmHg-1; P < 0.01 and P = 0.03, respectively] but not the cold water dive. However, [Formula: see text] was not different between conditions (P = 0.17). In conclusion, CB chemosensitivity was not attenuated during the cold stress diving condition and does not appear to contribute to changes in ventilation or CO2 retention.

Sugar-sweetened soft drink consumption acutely decreases spontaneous baroreflex sensitivity and heart rate variability.

In healthy humans, fructose-sweetened water consumption increases blood pressure variability (BPV) and decreases spontaneous cardiovagal baroreflex sensitivity (cBRS) and heart rate variability (HRV). However, whether consuming commercially available soft drinks containing high levels of fructose elicits similar responses is unknown. We hypothesized that high-fructose corn syrup (HFCS)-sweetened soft drink consumption increases BPV and decreases cBRS and HRV to a greater extent compared with artificially sweetened (diet) and sucrose-sweetened (sucrose) soft drinks and water. Twelve subjects completed four randomized, double-blinded trials in which they drank 500 mL of water or commercially available soft drinks matched for taste and caffeine content. We continuously measured beat-to-beat blood pressure (photoplethysmography) and R-R interval (ECG) before and 30 min after drink consumption during supine rest for 5 min during spontaneous and paced breathing. BPV was evaluated using standard deviation (SD), average real variability (ARV), and successive variation (SV) methods for systolic and diastolic blood pressure. cBRS was assessed using the sequence method. HRV was evaluated using the root mean square of successive differences (RMSSD) in R-R interval. There were no differences between conditions in the magnitude of change from baseline in SD, ARV, and SV (P ≥ 0.07). There were greater reductions in cBRS during spontaneous breathing in the HFCS (-3 ± 5 ms/mmHg) and sucrose (-3 ± 5 ms/mmHg) trials compared with the water trial (+1 ± 5 ms/mmHg, P < 0.03). During paced breathing, HFCS evoked greater reductions in RMSSD compared with water (-26 ± 34 vs. +2 ± 26 ms, P < 0.01). These findings suggest that sugar-sweetened soft drink consumption alters cBRS and HRV but not BPV.