Outcomes of Head and Neck Free Tissue Transfer in Renal Failure Patients.

OBJECTIVE: To assess if there is increased risk of free flap failure in renal failure patients undergoing head and neck reconstruction. We seek to primarily assess free flap outcomes based on stages of chronic kidney disease (CKD) and secondarily determine increased risk for postoperative complications. METHODS: Retrospective chart review was performed at five tertiary care centers. Patients were identified that had undergone microvascular free flap reconstruction of the head and neck with diagnosis of renal failure, classified as Stage 3 CKD or higher. Demographic data was collected. Outcomes in the postoperative period were examined. RESULTS: Seventy-three patients met inclusion criteria. The average patient age was 69 years with a male predominance (n = 48). The majority of patients had CKD Stage 3 (n = 52). Overall flap failure rate was 12.33% (n = 9, CKD stage 3 = 7.69%, CKD stage 4 = 30%, CKD stage 5 = 18%). There was an increased risk of flap failure on multivariate analysis for CKD stage 4/5 patients when compared to CKD 3 patients (p = 0.0095). When compared to matched controls, there was an increased risk of flap failure in CKD patients (p = 0.01) as well as an increased risk of overall complications (p < 0.0001). CONCLUSIONS: Patients with CKD undergoing head and neck reconstruction are at a higher risk of flap failure and overall complications. When comparing CKD stages there may be increased risk of flap failure in later stages of CKD compared to CKD 3. Appropriate patient counseling is recommended pre-operatively in this patient population with consideration for regional flaps in the appropriate patient. LEVEL OF EVIDENCE: 3 Laryngoscope, 134:688-694, 2024.

Effect of acute heat exposure on the pressor response to a voluntary hypoxic apnea.

The pressor response induced by a voluntary hypoxic apnea is mediated largely by increased sympathetic outflow. The neural control of blood pressure is altered in recovery from acute heat exposure, but its effect on the pressor response to a voluntary hypoxic apnea has never been explored. Therefore, we tested the hypothesis that prior heat exposure would attenuate the pressor response induced by a voluntary hypoxic apnea. Eleven healthy adults (five women) were exposed to whole body passive heating (water-perfused suit) sufficient to increase body core temperature by 1.2°C. Voluntary hypoxic apneas were performed at baseline and in recovery when body core temperature returned to ≤ 0.3°C of baseline. Participants breathed gas mixtures of varying [Formula: see text] (21%, 16%, and 12%; randomized) for 1 min followed by a 15-s end-expiratory apnea. The change in arterial oxygen saturation during each apnea did not differ from baseline to recovery (P = 0.6 for interaction), whereas the pressor response induced by a voluntary hypoxia apnea was reduced ([Formula: see text] 21%, baseline 17 ± 7 mmHg vs. recovery 14 ± 7 mmHg; [Formula: see text] 16%, baseline 24 ± 8 mmHg vs. recovery 18 ± 7 mmHg; [Formula: see text] 12%, baseline 28 ± 11 mmHg vs. recovery 24 ± 11 mmHg; P = 0.01 for main effect of time). These data suggest that prior heat exposure induces a cross-stressor effect such that the pressor response to a voluntary hypoxic apnea is attenuated.NEW & NOTEWORTHY The pressor response induced by a voluntary hypoxic apnea is mediated by increased sympathetic outflow. The neural control of blood pressure is altered in recovery from acute heat exposure, but its effect on the pressor response to a voluntary hypoxic apnea has never been explored. Our data suggest that prior heat exposure induces a cross-stressor effect such that the pressor response to a voluntary hypoxic apnea is attenuated.

Biomarkers related to gas embolism: Gas score, pathology, and gene expression in a gas bubble disease model.

Fish exposed to water supersaturated with dissolved gas experience gas embolism similar to decompression sickness (DCS), known as gas bubble disease (GBD) in fish. GBD has been postulated as an alternative to traditional mammals' models on DCS. Gas embolism can cause mechanical and biochemical damage, generating pathophysiological responses. Increased expression of biomarkers of cell damage such as the heat shock protein (HSP) family, endothelin 1 (ET-1) or intercellular adhesion molecule 1 (ICAM-1) has been observed, being a possible target for further studies of gas embolism. The GBD model consisted of exposing fish to supersaturation in water with approximately 170% total dissolved gas (TDG) for 18 hours, producing severe gas embolism. This diagnosis was confirmed by a complete histopathological exam and the gas score method. HSP70 showed a statistically significant upregulation compared to the control in all the studied organs (p <0.02). Gills and heart showed upregulation of HSP90 with statistical significance (p = 0.015 and p = 0.02, respectively). In addition, HSP70 gene expression in gills was positively correlated with gas score (p = 0.033). These results suggest that gas embolism modify the expression of different biomarkers, with HSP70 being shown as a strong marker of this process. Furthermore, gas score is a useful tool to study the abundance of gas bubbles, although individual variability always remains present. These results support the validity of the GBD model in fish to study gas embolism in diseases such as DCS.

Optimizing Innervation in Radial Forearm Phalloplasty: Consider the Posterior Antebrachial Cutaneous Nerve.

SUMMARY: One goal of an ideal phallic reconstruction is achieving tactile and erogenous sensation. Traditionally, the most common flap used in phalloplasty has been the radial forearm flap, where the medial and lateral antebrachial cutaneous nerves are coapted to meet this goal. The purpose of this article is to draw attention to the lesser-known posterior antebrachial cutaneous nerve (PABC) as an alternative or additional nerve for coaptation that innervates a majority of the shaft, where sensation is most desired. The presence, anatomical location, and territory of innervation of the antebrachial cutaneous nerves were assessed in a series of 12 consecutive in vivo radial forearm phalloplasties. A literature review was conducted to establish which nerves have traditionally been used for sensory reinnervation of the phallus. The PABC was the first nerve encountered on the radial border of the flap lying on the fascia in the interval between the brachioradialis and extensor carpi radials longus. The posterior and lateral antebrachial cutaneous nerves innervated the phallic shaft, whereas the anterior branch of the medial antebrachial cutaneous nerve innervated the phallic urethra. There were no articles in our review that used PABC for nerve coaptation in radial forearm phalloplasty. The skin innervated by the PABC represents a significant portion of the phallic shaft when using the standard template for radial forearm phalloplasty. Despite this, its use is not described in the literature. The authors introduce the PABC as an alternative or additional nerve for coaptation in radial forearm phalloplasty.

Cardiovascular Adjustments After Acute Heat Exposure.

In this review, we highlight recent studies from our group and others that have characterized the cardiovascular adjustments that occur after acute heat exposure. Special emphasis will be placed on underlying mechanisms and clinical implications. Finally, we postulate that these acute cardiovascular adjustments may predict the long-term adaptive response to chronic heat therapy.

Hydrocarbon ladder polymers with ultrahigh permselectivity for membrane gas separations.

Membranes have the potential to substantially reduce energy consumption of industrial chemical separations, but their implementation has been limited owing to a performance upper bound-the trade-off between permeability and selectivity. Although recent developments of highly permeable polymer membranes have advanced the upper bounds for various gas pairs, these polymers typically exhibit limited selectivity. We report a class of hydrocarbon ladder polymers that can achieve both high selectivity and high permeability in membrane separations for many industrially relevant gas mixtures. Additionally, their corresponding films exhibit desirable mechanical and thermal properties. Tuning of the ladder polymer backbone configuration was found to have a profound effect on separation performance and aging behavior.

Acute heat exposure protects against endothelial ischemia-reperfusion injury in aged humans.

Nonpharmacological therapies that protect against endothelial ischemia-reperfusion injury (I/R) remain limited in aged adults. Acute heat exposure protects against endothelial I/R injury in young adults, but its efficacy has never been explored in aged adults. Therefore, we tested the hypothesis that acute heat exposure would prevent the attenuation of endothelium-dependent vasodilation after I/R injury in aged adults. Nine (2 men, 69 ± 8 yr) aged adults were exposed to a thermoneutral control condition or whole body passive heating (water-perfused suit) sufficient to increase body core temperature by 1.2°C. Experiments were separated by at least 7 days. Heat exposure was always performed first to time match the thermoneutral control condition. Endothelium-dependent vasodilation was assessed via flow-mediated dilation of the brachial artery before (pre-I/R) and after I/R injury (post-I/R), which was induced by 20 min of arm ischemia followed by 20 min of reperfusion. Flow-mediated dilation was reduced following I/R injury for the thermoneutral control condition (pre-I/R, 4.5 ± 2.9% vs. post-I/R, 0.9 ± 2.8%, P < 0.01), but was well maintained with prior heat exposure (pre-I/R, 4.4 ± 2.8% vs. post-I/R, 3.5 ± 2.8%, P = 0.5). Taken together, acute heat exposure protects against endothelial I/R injury in aged adults. These results highlight the therapeutic potential of heat therapy to prevent endothelial dysfunction associated with I/R injury in aged adults who are most at risk for an ischemic event.

Mucoepidermoid Carcinomas of the Larynx.

OBJECTIVES: Discussions regarding the specific management and outcomes for laryngeal MEC are limited to very small, single-institution case series. To look further into the diagnosis and management of these uncommon non-squamous cell carcinomas of the larynx, we present 3 recent cases of laryngeal MEC treated at our institution. METHODS: Patients at a tertiary hospital treated for MEC between October 2019 and December 2020 were retrospectively identified. Chart review, imaging analysis, and histologic slide creation were completed for all patients. RESULTS: We identified and treated 2 patients with high-grade supraglottic and 1 patient with intermediate-grade glottic MEC. These patients presented to our clinic with a primary complaint of either gradual, worsening dysphonia, dysphagia, or both. All patients underwent laryngovideostroboscopy as well as panendoscopy with directed submucosal biopsy, which was consistent with MEC. MRI was performed in 2 of the cases further elucidating the extent of submucosal spread. PET-CT was performed in all 3 cases, and none demonstrated evidence of regional or distal metastases. Surgically, high-grade MEC lesions were treated with a total laryngectomy. The intermediate MEC lesion was managed with a supracricoid partial laryngectomy (SCPL). Surgical margins were free of tumor in all cases with no nodal metastases by modified radical neck dissection. Radiation therapy was offered to both high-grade MEC patients and declined by one. Radiation was not recommended to the patient with intermediate-grade MEC as we believed that the risk of additional treatment outweighed the benefit. CONCLUSION: We believe that MEC of the larynx should be considered in patients with atypical submucosal laryngeal masses. Laryngovideostroboscopy, MRI, and PET imaging may be valuable in determining the extent of the lesions and planning appropriate surgery. Postoperative radiation therapy should be considered a per tumor grade in other more studied sites, as there is no data on efficacy in laryngeal MEC.

Acute heat exposure improves microvascular function in skeletal muscle of aged adults.

Acute heat exposure improves microvascular function in aged adults as assessed using reactive hyperemia. The cutaneous and skeletal muscle microcirculations are thought to contribute to this response, but this has never been confirmed due to the methodological challenges associated with differentiating blood flow between these vascular beds. We hypothesized that acute hot water immersion would improve endothelial-dependent, but not endothelial-independent vasodilation in the microcirculation of the vastus lateralis muscle in healthy aged adults. Participants (70 ± 5 yr) were immersed for 60 min in thermoneutral (36°C) or hot (40°C) water. Ninety minutes following immersion, skeletal muscle microdialysis was used to bypass the cutaneous circulation and directly assess endothelial-dependent and endothelial-independent vasodilation by measuring the local hyperemic response to graded infusions of acetylcholine (ACh, 27.5 and 55.0 mM) and sodium nitroprusside (SNP, 21 and 42 mM), respectively. The hyperemic response to 27.5 mM ACh did not differ between thermal conditions (P = 0.9). However, the hyperemic response to 55.0 mM ACh was increased with prior hot water immersion (thermoneutral immersion, 43.9 ± 23.2 mL/min/100 g vs. hot water immersion, 66.5 ± 25.5 mL/min/100 g; P < 0.01). Similarly, the hyperemic response to 21 mM SNP did not differ between thermal conditions (P = 0.3) but was increased following hot water immersion with the infusion of 42 mM SNP (thermoneutral immersion, 48.8 ± 25.6 mL/min/100 g vs. hot water immersion, 90.7 ± 53.5 mL/min/100 g; P < 0.01). These data suggest that acute heat exposure improves microvascular function in skeletal muscle of aged humans.NEW & NOTEWORTHY Acute heat exposure improves microvascular function in aged adults as assessed using reactive hyperemia. The cutaneous and skeletal muscle microcirculations are thought to contribute to this response, but this has never been confirmed due to the methodological challenges associated with differentiating blood flow between these vascular beds. Using the microdialysis technique to bypass the cutaneous circulation, we demonstrated that heat exposure improves endothelial-dependent and endothelial-independent vasodilation in the microcirculation of skeletal muscle in aged humans.

Implications of Tumor Characteristics and Treatment Modality on Local Recurrence and Functional Outcomes in Children With Chest Wall Sarcoma: A Pediatric Surgical Oncology Research Collaborative Study.

OBJECTIVE: To determine the impact of tumor characteristics and treatment approach on (1) local recurrence, (2) scoliosis development, and (3) patient-reported quality of life in children with sarcoma of the chest wall. SUMMARY OF BACKGROUND DATA: Children with chest wall sarcoma require multimodal therapy including chemotherapy, surgery, and/or radiation. Despite aggressive therapy which places them at risk for functional impairment and scoliosis, these patients are also at significant risk for local recurrence. METHODS: A multi-institutional review of 175 children (median age 13 years) with chest wall sarcoma treated at seventeen Pediatric Surgical Oncology Research Collaborative institutions between 2008 and 2017 was performed. Patient-reported quality of life was assessed prospectively using PROMIS surveys. RESULTS: The most common diagnoses were Ewing sarcoma (67%) and osteosarcoma (9%). Surgical resection was performed in 85% and radiation in 55%. A median of 2 ribs were resected (interquartile range = 1-3), and number of ribs resected did not correlate with margin status ( P = 0.36). Local recurrence occurred in 23% and margin status was the only predictive factor(HR 2.24, P = 0.039). With a median follow-up of 5 years, 13% developed scoliosis (median Cobb angle 26) and 5% required corrective spine surgery. Scoliosis was associated with posteriorrib resection (HR 8.43; P= 0.003) and increased number of ribs resected (HR 1.78; P = 0.02). Overall, patient-reported quality of life is not impaired after chest wall tumor resection. CONCLUSIONS: Local recurrence occurs in one-quarter of children with chest wall sarcoma and is independent of tumor type. Scoliosis occurs in 13% of patients, but patient-reported quality of life is excellent.

Shear stress induced by acute heat exposure is not obligatory to protect against endothelial ischemia-reperfusion injury in humans.

Acute heat exposure protects against endothelial ischemia-reperfusion (I/R) injury in humans. However, the mechanism/s mediating this protective effect remain unclear. We tested the hypothesis that inhibiting the increase in shear stress induced by acute heat exposure would attenuate the protection of endothelial function following I/R injury. Nine (3 women) young healthy participants were studied under three experimental conditions: 1) thermoneutral control; 2) whole body heat exposure to increase body core temperature by 1.2°C; and 3) heat exposure + brachial artery compression to inhibit the temperature-dependent increase in shear stress. Endothelial function was assessed via brachial artery flow-mediated dilatation before (pre-I/R) and after (post-I/R) 20 min of arm ischemia followed by 20 min of reperfusion. Brachial artery shear rate was increased during heat exposure (681 ± 359 s-1), but not for thermoneutral control (140 ± 63 s-1; P < 0.01 vs. heat exposure) nor for heat + brachial artery compression (139 ± 60 s-1; P < 0.01 vs. heat exposure). Ischemia-reperfusion injury reduced flow-mediated dilatation following thermoneutral control (pre-I/R, 5.5 ± 2.9% vs. post-I/R, 3.8 ± 2.9%; P = 0.06), but was protected following heat exposure (pre-I/R, 5.8 ± 2.9% vs. post-I/R, 6.1 ± 2.9%; P = 0.5) and heat + arterial compression (pre-I/R, 4.4 ± 2.8% vs. post-I/R, 5.8 ± 2.8%; P = 0.1). Contrary to our hypothesis, our findings demonstrate that shear stress induced by acute heat exposure is not obligatory to protect against endothelial I/R injury in humans.NEW & NOTEWORTHY Acute heat exposure protects against endothelial ischemia-reperfusion injury in humans. However, the mechanism/s mediating this protective effect remain unclear. We utilized arterial compression to inhibit the temperature-dependent increase in brachial artery blood velocity that occurs during acute heat exposure to isolate the contribution of shear stress to the protection of endothelial function following ischemia-reperfusion injury. Our findings demonstrate that shear stress induced by acute heat exposure is not obligatory to protect against endothelial I/R injury.

Influence of ischemia-reperfusion injury on endothelial function in men and women with similar serum estradiol concentrations.

Prior data suggest that, relative to the early follicular phase, women in the late follicular phase are protected against endothelial ischemia-reperfusion (I/R) injury when estradiol concentrations are highest. In addition, endothelial I/R injury is consistently observed in men with naturally low endogenous estradiol concentrations that are similar to those of women in the early follicular phase. Therefore, the purpose of this study was to determine whether the vasodeleterious effect of I/R injury differs between women in the early follicular phase of the menstrual cycle and age-matched men. We tested the hypothesis that I/R injury would attenuate endothelium-dependent vasodilation to the same extent in women and age-matched men with similar circulating estradiol concentrations. Endothelium-dependent vasodilation was assessed via brachial artery flow-mediated dilation (duplex ultrasound) in young healthy men (n = 22) and women (n = 12) before (pre-I/R) and immediately after (post-I/R) I/R injury, which was induced via 20 min of arm circulatory arrest followed by 20-min reperfusion. Serum estradiol concentrations did not differ between sexes (men 115.0 ± 33.9 pg·mL-1 vs. women 90.5 ± 40.8 pg·mL-1; P = 0.2). The magnitude by which I/R injury attenuated endothelium-dependent vasodilation did not differ between men (pre-I/R 5.4 ± 2.4% vs. post-I/R 3.0 ± 2.7%) and women (pre-I/R 6.1 ± 2.8% vs. post-I/R 3.7 ± 2.7%; P = 0.9). Our data demonstrate that I/R injury similarly reduces endothelial function in women in the early follicular phase of the menstrual cycle and age-matched men with similar estradiol concentrations.

Trends in robotic surgery utilization across tertiary children's hospitals in the United States.

BACKGROUND: A growing number of tertiary children's hospitals are utilizing robotic surgical technology. We sought to characterize national trends in pediatric surgical robotic case utilization and related drivers. METHODS: Pediatric urology and pediatric surgery (abdominal and thoracic) procedures, performed from January 2010 to December 2019 across 19 U.S. tertiary care children's hospitals, were identified using the Pediatric Health Information System (PHIS). Trends in robot utilization were evaluated by surgical subspecialty, procedure type, and number of individual operating surgeons. RESULTS: Increases were noted in the overall numbers of pediatric surgery (1.3% per quarter, p = 0.005) and urology robotic procedures (2.0% per quarter, p < 0.001), as well as the numbers of pediatric surgeons (7.5% per year, p < 0.001) and pediatric urologists (7.8% per year, p < 0.001) operating robotically. Biliary system and spleen surgery were the most common robotic pediatric surgery procedures (45.5%) and had stable utilization over time (- 0.8% per quarter, 95% CI - 2.3-0.8). Robotic foregut surgery showed the most rapid growth in utilization (2.1% per quarter, 95% CI 0.7-3.6, p = 0.004) in pediatric surgery, while mediastinal/thoracic surgery demonstrated a decrease in utilization (- 4.6%, 95% CI - 7.9-1.2, p = 0.008). Renal pelvis/ureter surgery was the most common robotic urologic procedure (55.8%) and also demonstrated the fastest growth utilization (2.2% per quarter, 95% CI 1.5-2.9, p < 0.001) in urology. CONCLUSIONS: Utilization of robotic-assisted surgery in pediatric surgery and pediatric urology has increased both in case volume and the number of operating surgeons, with foregut and renal pelvis/ureter surgery responsible for the areas of greatest growth.

Assessing opioid administration in pediatric burn patients with nonsurgical management.

BACKGROUND: Despite the vast literature studying the opioid crisis, sparse data describe this in the pediatric burn population. This study sought to assess patient-level characteristics and their potential effects on opioid administration in nonsurgical pediatric burn inpatients. METHODS: Admitted burn patients from 2013 to 2018 with nonsurgical management at an American Burn Association (ABA) verified pediatric burn center were retrospectively identified. Morphine milligram equivalents by weight (MME/kg) per admission were evaluated through a multiple loglinear regression with race, sex, age, total body surface area burned (TBSA), and burn depth as predictors. Simple linear regression was used to evaluate the temporal trend of median opioid utilization. RESULTS: A total of 806 patients (55% White, 35% Black, 5% Hispanic, 5% Other) were included. In an adjusted analysis, no differences in opioid administration were seen by sex, burn degree, or for Blacks and Hispanics when compared with Whites. Increased MME/kg was associated with older age (10-18 years; p<0.0001) and larger burns (>5% TBSA burned; p<0.0001). From 2013 to 2018, median MME/kg per admission declined significantly (2013:0.21, 2018:0.09; p=0.0103). CONCLUSIONS: Nonsurgical burn patients who were older and presented with larger TBSA experienced marked increases in opioid utilization. Overall, opioid administration decreased over time.

Effect of endoplasmic reticulum stress on endothelial ischemia-reperfusion injury in humans.

Endoplasmic reticulum stress contributes to ischemia-reperfusion (I/R) injury in rodent and cell models. However, the contribution of endoplasmic reticulum stress in the pathogenesis of endothelial I/R injury in humans is unknown. We tested the hypothesis that compared with placebo, inhibition of endoplasmic reticulum stress via ingestion of tauroursodeoxycholic acid would prevent the attenuation of endothelium-dependent vasodilation following I/R injury. Twelve young adults (6 women) were studied following ingestion of a placebo or 1,500 mg tauroursodeoxycholic acid (TUDCA). Endothelium-dependent vasodilation was assessed via brachial artery flow-mediated dilation (duplex ultrasonography) before and after I/R injury, which was induced by 20 min of arm ischemia followed by 20 min of reperfusion. Endothelium-independent vasodilation (glyceryl trinitrate-mediated vasodilation) was also assessed after I/R injury. Compared with placebo, TUDCA ingestion increased circulating plasma concentrations by 145 ± 90 ng/ml and increased concentrations of the taurine unconjugated form, ursodeoxycholic acid, by 560 ± 156 ng/ml (both P < 0.01). Ischemia-reperfusion injury attenuated endothelium-dependent vasodilation, an effect that did not differ between placebo (pre-I/R, 5.0 ± 2.1% vs. post-I/R, 3.5 ± 2.2%) and TUDCA (pre-I/R, 5.6 ± 2.1% vs. post-I/R, 3.9 ± 2.1%; P = 0.8) conditions. Similarly, endothelium-independent vasodilation did not differ between conditions (placebo, 19.6 ± 4.8% vs. TUDCA, 19.7 ± 6.1%; P = 0.9). Taken together, endoplasmic reticulum stress does not appear to contribute to endothelial I/R injury in healthy young adults.

Neural control of blood pressure is altered following isolated leg heating in aged humans.

There is a sustained reduction in arterial blood pressure that occurs in aged adults following exposure to acute leg heating. We tested the hypothesis that acute leg heating would decrease arterial blood pressure in aged adults secondary to sympathoinhibition. We exposed 13 young and 10 aged adults to 45 min of leg heating. Muscle sympathetic nerve activity (radial nerve) was measured before leg heating (preheat) and 30 min after (recovery) and is expressed as burst frequency. Neurovascular transduction was examined by assessing the slope of the relation between muscle sympathetic nerve activity and leg vascular conductance measured at rest and during isometric handgrip exercise performed to fatigue. Arterial blood pressure was well maintained in young adults (preheat, 86 ± 6 mmHg vs. recovery, 88 ± 7 mmHg; P = 0.4) due to increased sympathetic nerve activity (preheat, 16 ± 7 bursts/min vs. recovery, 22 ± 10 bursts/min; P < 0.01). However, in aged adults, sympathetic nerve activity did not differ from preheat (37 ± 5 bursts/min) to recovery (33 ± 6 bursts/min, P = 0.1), despite a marked reduction in arterial blood pressure (preheat, 101 ± 7 mmHg vs. recovery, 94 ± 6 mmHg; P < 0.01). Neurovascular transduction did not differ from preheat to recovery for either age group (P ≥ 0.1). The reduction in arterial blood pressure that occurs in aged adults following exposure to acute leg heating is mediated, in part, by a sympathoinhibitory effect that alters the compensatory neural response to hypotension.NEW & NOTEWORTHY There is a sustained reduction in arterial blood pressure that occurs in aged adults following exposure to acute leg heating. However, the neurovascular mechanisms mediating this response remain unknown. Our findings demonstrate for the first time that this reduction in arterial blood pressure is mediated, in part, by a sympathoinhibitory effect that alters the compensatory neural response to hypotension in aged adults.

Vertical Clinging and Leaping Ahead: How Bamboo Has Shaped the Anatomy and Physiology of Hapalemur.

Hapalemur sps. and Prolemur simus (bamboo lemurs, collectively) stand out from the relatively homogeneous lemurids because they are bamboo feeders and vertical clingers and leapers. This unique diet presents equally unique challenges, like its verticality, toughness, and toxicity. The bamboo lemurs share the generalized anatomy of the other lemurids, but also display some well-documented skeletal adaptations, perhaps to overcome the problems presented by their specialization. Soft-tissue adaptations, however, remain largely unexplored. Explored here are possible soft-tissue adaptations in Hapalemur griseus. We compare H. griseus with other lemurids, Propithecus, Galago, Tarsier, and a tree shrew. Based on the available anatomical and physiological data, we hypothesize that Hapalemur and Prolemur species will have differences in hindlimb morphology when compared with other lemurids. We predict that H. griseus will have more hindlimb muscle mass and will amplify muscle mass differences with increased type II muscle fibers. Relative hindlimb muscle mass in H. griseus is less than other prosimians sampled, yet relative sural muscle mass is significantly heavier (P < 0.01) in H. griseus. Results show that the soleus muscle of H. griseus has a higher amount of type II (fast) fibers in plantarflexors. These findings indicate although H. griseus shares some generalized lemurid morphology, its diet of bamboo may have pushed this generalized lemurid to an anatomical extreme. We suspect additional bamboo-specific adaptations in their anatomy and physiology will be uncovered with further examination into the anatomy of the bamboo lemurs. Anat Rec, 2019. © 2019 Wiley Periodicals, Inc. Anat Rec, 303:295-307, 2020. © 2019 American Association for Anatomy.

Acute lower leg hot water immersion protects macrovascular dilator function following ischaemia-reperfusion injury in humans.

NEW FINDINGS: • What is the central question of this study? What is the effect of lower leg hot water immersion on vascular ischaemia-reperfusion injury induced in the arm of young healthy humans? • What is the main finding and its importance? Lower leg hot water immersion successfully protects against vascular ischaemia-reperfusion injury in humans. This raises the possibility that targeted heating of the lower legs may be an alternative therapeutic approach to whole-body heating that is equally efficacious at protecting against vascular ischaemia-reperfusion injury. ABSTRACT: Reperfusion that follows a period of ischaemia paradoxically reduces vasodilator function in humans and contributes to the tissue damage associated with an ischaemic event. Acute whole-body hot water immersion protects against vascular ischaemia-reperfusion (I-R) injury in young healthy humans. However, the effect of acute lower leg heating on I-R injury is unclear. Therefore, the purpose of this study was to test the hypothesis that, compared with thermoneutral control immersion, acute lower leg hot water immersion would prevent the decrease in macro- and microvascular dilator functions following I-R injury in young healthy humans. Ten young healthy subjects (5 female) immersed their lower legs into a circulated water bath for 60 min under two randomized conditions: (1) thermoneutral control immersion (∼33°C) and (2) hot water immersion (∼42°C). Macrovascular (brachial artery flow-mediated dilatation) and microvascular (forearm reactive hyperaemia) dilator functions were assessed using Doppler ultrasound at three time points: (1) pre-immersion, (2) 60 min post-immersion, and (3) post-I/R (20 min of arm ischaemia followed by 20 min of reperfusion). Ischaemia-reperfusion injury reduced macrovascular dilator function following control immersion (pre-immersion 6.0 ± 2.1% vs. post-I/R 3.6 ± 2.1%; P < 0.05), but was well-maintained with prior hot water immersion (pre-immersion 5.8 ± 2.1% vs. post-I/R 5.3 ± 2.1%; P = 0.8). Microvascular dilator function did not differ between conditions or across time. Taken together, acute lower leg hot water immersion prevents the decrease in macrovascular dilator function that occurs following I-R injury in young healthy humans.

Facile Synthesis and Study of Microporous Catalytic Arene-Norbornene Annulation-Tröger's Base Ladder Polymers for Membrane Air Separation.

We report the facile synthesis and study of two soluble microporous ladder polymers, CANAL-TBs, by combining catalytic arene-norbornene annulation (CANAL) and Tröger's base (TB) formation. The polymers were synthesized in two steps from commercially available chemicals in high yields. CANAL-TBs easily formed mechanically robust films, were thermally stable up to 440 °C, and exhibited very high Brunauer-Teller-Emmett surface areas of 900-1000 m2 g-1. The gas separation performance of the CANAL-TBs for the O2/N2 pair is located between the 2008 and 2015 permeability/selectivity upper bounds. After 300 days of aging, CANAL-TBs still exhibited O2 permeability of 200-500 barrer with O2/N2 selectivity of about 5. The polymer with more methyl substituents exhibited higher permeability and slightly larger intersegmental spacing as revealed by WAXS, presumably due to more frustrated chain packing. The facile synthesis, excellent mechanical properties, and promising air separation performance of the CANAL-TB polymers make them attractive membrane materials for various air separation applications, such as aircraft on-board nitrogen generation and oxygen enrichment for combustion.