Maternal self-reported polycystic ovary syndrome with offspring and maternal cardiometabolic outcomes.

STUDY QUESTION: Do children born to mothers with polycystic ovary syndrome (PCOS) have an adverse cardiometabolic profile including arterial stiffness at 9 years of age compared to other children? SUMMARY ANSWER: Children of mothers with PCOS did not have differing cardiometabolic outcomes than children without exposure. WHAT IS KNOWN ALREADY: While women with PCOS themselves have higher risk of cardiometabolic conditions such as obesity and diabetes, the evidence on intergenerational impact is unclear. Given in utero sequalae of PCOS (e.g. hyperandrogenism, insulin resistance), the increased risk could be to both boys and girls. STUDY DESIGN, SIZE, DURATION: The Upstate KIDS cohort is a population-based birth cohort established in 2008-2010 to prospectively study the impact of infertility treatment on children's health. After ∼10 years of follow-up, 446 mothers and their 556 children attended clinical visits to measure blood pressure (BP), heart rate, arterial stiffness by pulse wave velocity (PWV), mean arterial pressure, lipids, high-sensitivity C-reactive protein (hsCRP), hemoglobin A1c (HbA1c), and anthropometrics. PARTICIPANTS/MATERIALS, SETTING, METHODS: Women self-reported ever diagnoses of PCOS ∼4 months after delivery of their children in 2008-2010. Linear regression models applying generalized estimating equations to account for correlation within twins were used to examine associations with each childhood cardiometabolic outcome. MAIN RESULTS AND THE ROLE OF CHANCE: In this cohort with women oversampled on infertility treatment, ∼14% of women reported a PCOS diagnosis (n = 61). We observed similarities in BP, heart rate, PWV, lipids, hsCRP, HbA1c, and anthropometry (P-values >0.05) among children born to mothers with and without PCOS. Associations did not differ by child sex. LIMITATIONS, REASONS FOR CAUTION: The sample size of women with PCOS precluded further separation of subgroups (e.g. by hirsutism). The population-based approach relied on self-reported diagnosis of maternal PCOS even though self-report has been found to be valid. Participants were predominantly non-Hispanic White and a high proportion were using fertility treatment due to the original design. Differences in cardiometabolic health may be apparent later in age, such as after puberty. WIDER IMPLICATIONS OF THE FINDINGS: Our results provide some reassurance that cardiometabolic factors do not differ in children of women with and without self-reported PCOS during pregnancy. STUDY FUNDING/COMPETING INTEREST(S): Supported by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, United States (contracts #HHSN275201200005C, #HHSN267200700019C, #HHSN275201400013C, #HHSN275201300026I/27500004, #HHSN275201300023I/27500017). The authors have no conflicts of interest. REGISTRATION NUMBER: NCT03106493.

Accuracy of heart rate measured by military-grade wearable ECG monitor compared with reference and commercial monitors.

INTRODUCTION: Physiological monitoring of soldiers can indicate combat readiness and performance. Despite demonstrated use of wearable devices for HR monitoring, commercial options lack desired military features. A newly developed OMNI monitor includes desired features such as long-range secure data transmission. This study investigated the accuracy of the OMNI to measure HR via accuracy of R-R interval duration relative to research-grade ECG and commercial products. METHODS: 54 healthy individuals (male/female=37/17, age=22.2±3.6 years, height=173.0±9.1 cm, weight=70.1±11.2 kg) completed a submaximal exercise test while wearing a reference ECG (Biopac) and a randomly assigned chest-based monitor (OMNI, Polar H10, Equivital EQ-02, Zephyr Bioharness 3). All participants also wore two wrist-based photoplethysmography (PPG) devices, Garmin fenix 6 and Empatica E4. Bland-Altman analyses of agreement, concordance correlation coefficient (CCC) and root-mean-squared error (RMSE) were used to determine accuracy of the OMNI and commercial devices relative to Biopac. Additionally, a linear mixed-effects model evaluated the effects of device and exercise intensity on agreement. RESULTS: Chest-based devices showed superior agreement with Biopac for measuring R-R interval compared with wrist-based ones in terms of mean bias, CCC and RMSE, with OMNI demonstrating the best scores on all metrics. Linear mixed-effects model showed no significant main or interaction effects for the chest-based devices. However, significant effects were found for Garmin and Empatica devices (p<0.001) as well as the interaction effects between both Garmin and Empatica and exercise intensity (p<0.001). CONCLUSIONS: Chest-based ECG devices are preferred to wrist-based PPG devices due to superior HR accuracy over a range of exercise intensities, with the OMNI device demonstrating equal, if not superior, performance to other commercial ECG monitors. Additionally, wrist-based PPG devices are significantly affected by exercise intensity as they underestimate HR at low intensities and overestimate HR at high intensities.

"Much better than I thought it was going to be": Telehealth delivered group-based education and exercise was perceived as acceptable among people with knee osteoarthritis.

Objective: To understand patient perceived acceptability of participating in a telehealth delivered group-based education and exercise-therapy program for knee osteoarthritis. Design: This qualitative study involved semi-structured, one-on-one interviews with knee osteoarthritis patients who have completed the Good Living with osteoArthritis from Denmark (GLA:D®) program via telehealth or in-person. Interviews were recorded, transcribed verbatim, coded, and analysed using an inductive content analysis approach, focusing on themes related to telehealth. Results: Nineteen participants [12 (63%) female, mean aged 62 years, range 49-72 years] were included. Eleven (58%) received GLA:D® via telehealth and 8 (42%) attended in-person sessions. Two overarching themes (6 sub-themes) related to telehealth perceived acceptability were identified: 1) Perceptions of telehealth acceptability was highly influenced by exposure. Individuals who had received telehealth considered it easy, convenient, and flexible, whereas telehealth was perceived to be inferior and misunderstood by those without exposure. 2) Telehealth participants reported similar program benefits to in-person participants, including reduced fear of pain and joint damage, changed beliefs in value of exercise, and stated improvements in pain and function. Conclusions: Telehealth delivery of group-based education and exercise-therapy for knee osteoarthritis was acceptable for people who had experienced it and provides similar benefits as in-person care for pain and beliefs about the safety and value of exercise. Wider implementation of telehealth group-based education and exercise-therapy may improve access to high value care for people with knee osteoarthritis.

Demography of an ice-obligate mysticete in a region of rapid environmental change.

Antarctic minke whales (Balaenoptera bonaerensis, AMW) are an abundant, ice-dependent species susceptible to rapid climatic changes occurring in parts of the Antarctic. Here, we used remote biopsy samples and estimates of length derived from unoccupied aircraft system (UAS) to characterize for the first time the sex ratio, maturity, and pregnancy rates of AMWs around the Western Antarctic Peninsula (WAP). DNA profiling of 82 biopsy samples (2013-2020) identified 29 individual males and 40 individual females. Blubber progesterone levels indicated 59% of all sampled females were pregnant, irrespective of maturity. When corrected for sexual maturity, the median pregnancy rate was 92.3%, indicating that most mature females become pregnant each year. We measured 68 individuals by UAS (mean = 8.04 m) and estimated that 66.5% of females were mature. This study provides the first data on the demography of AMWs along the WAP and represents the first use of non-lethal approaches to studying this species. Furthermore, these results provide baselines against which future changes in population status can be assessed in this rapidly changing marine ecosystem.

Does land-based exercise-therapy improve physical activity in people with knee osteoarthritis? A systematic review with meta-analyses.

PRIMARY OBJECTIVE: Investigate the effects of land-based exercise-therapy on physical activity in people with knee osteoarthritis (KOA). DESIGN: Systematic review and meta-analysis of randomised or quasi-randomised trials investigating land-based exercise-therapy on physical activity, fitness, and general health in people with KOA. We updated a 2013 Cochrane review search on exercise-therapy for KOA in April 2021 and applied the Cochrane Risk-of-Bias Tool 1.0 to included articles. Standardised mean differences (SMDs) and 95% confidence intervals (CI) were calculated. GRADE was used to assess certainty of the evidence. RESULTS: Twenty-eight randomised controlled trials (2,789 participants) evaluating the effects of resistance-training (n = 10), walking (n = 6) and mixed-exercise programs (n = 7) were identified. Low to moderate certainty evidence indicated small increases in physical activity for exercise-therapy compared to non-exercise interventions in the short-term (SMD, 95% CI = 0.29, 0.09 to 0.50), but not the medium- (0.03, -0.11 to 0.18) or long-term (-0.06, -0.34 to 0.22). Low certainty evidence indicated large increases in physical activity for walking programs (0.53, 0.11 to 0.95) and mixed-exercise programs (0.67, 0.37 to 0.97) compared to non-exercise interventions in the short-term. Low certainty evidence indicated moderate and small increases in physical activity for resistance-training combined with education focused on pain coping skills and self-efficacy compared to education alone at medium-term follow-up (0.45, 0.19 to 0.71). CONCLUSION: Walking and mixed-exercise, but not resistance-training, may improve physical activity in people with KOA in the short-term. Combining resistance-training with education may increase physical activity in the medium-, but not the long-term, highlighting the potential importance of developing more effective longer-term interventions for people with KOA. Future studies evaluating land-based exercise-therapy are encouraged to include physical activity outcomes and longer-term follow-up to increase the certainty of evidence.

PHASE: An Open-Source Program for the Analysis of DrosophilaPhase, Activity, and Sleep Under Entrainment.

The problem of entrainment is central to circadian biology. In this regard, Drosophila has been an important model system. Owing to the simplicity of its nervous system and the availability of powerful genetic tools, the system has shed significant light on the molecular and neural underpinnings of entrainment. However, much remains to be learned regarding the molecular and physiological mechanisms underlying this important phenomenon. Under cyclic light/dark conditions, Drosophila melanogaster displays crepuscular patterns of locomotor activity with one peak anticipating dawn and the other anticipating dusk. These peaks are characterized through an estimation of their phase relative to the environmental light cycle and the extent of their anticipation of light transitions. In Drosophila chronobiology, estimations of phases are often subjective, and anticipation indices vary significantly between studies. Though there is increasing interest in building flexible analysis tools in the field, none incorporates objective measures of Drosophila activity peaks in combination with the analysis of fly activity/sleep in the same program. To this end, we have developed PHASE, a MATLAB-based program that is simple and easy to use and (i) supports the visualization and analysis of activity and sleep under entrainment, (ii) allows analysis of both activity and sleep parameters within user-defined windows within a diurnal cycle, (iii) uses a smoothing filter for the objective identification of peaks of activity (and therefore can be used to quantitatively characterize them), and (iv) offers a series of analyses for the assessment of behavioral anticipation of environmental transitions.

The Christchurch mosque shooting, the media, and subsequent gun control reform in New Zealand: a descriptive analysis.

In March 2019, a mass shooting at two Christchurch mosques, livestreamed to Facebook, resulted in the deaths of 51 people. Psychologically, this served as a focusing event with high threat salience, shocking a country unused to gun violence despite its comparatively lax firearm legislation. The unprecedented reluctance by the New Zealand media to feature the shooter as a protagonist or even publish his name, concentrating instead on victims and societal issues, helped promote a sense of collective responsibility for change. This was strongly modeled by political leaders. Within weeks, new gun control laws were introduced with bipartisan support. We present this as a national case study, considering psychological and societal enablers for legislative reform in response to extreme gun violence. The shooting also raised the intractable problem of the internet allowing terrorists to promulgate violent content and extremist ideology with regulation in this area harder to achieve than gun control.

Hemispheric asymmetry in ocean change and the productivity of ecosystem sentinels.

Climate change and other human activities are causing profound effects on marine ecosystem productivity. We show that the breeding success of seabirds is tracking hemispheric differences in ocean warming and human impacts, with the strongest effects on fish-eating, surface-foraging species in the north. Hemispheric asymmetry suggests the need for ocean management at hemispheric scales. For the north, tactical, climate-based recovery plans for forage fish resources are needed to recover seabird breeding productivity. In the south, lower-magnitude change in seabird productivity presents opportunities for strategic management approaches such as large marine protected areas to sustain food webs and maintain predator productivity. Global monitoring of seabird productivity enables the detection of ecosystem change in remote regions and contributes to our understanding of marine climate impacts on ecosystems.

Infertility treatment and autism risk using the Modified Checklist for Autism in Toddlers (M-CHAT).

STUDY QUESTION: Are toddlers conceived by fertility treatment at higher risk of failing a screening tool for autism spectrum disorders (ASD) than toddlers not conceived by treatment? SUMMARY ANSWER: Compared with children not conceived by infertility treatment, children conceived by any infertility treatment, ovulation induction with or without intrauterine insemination (OI/IUI), or assisted reproductive technologies (ART) appeared to have had higher odds of failing an ASD screening; however, results were inconclusive and need replication. WHAT IS KNOWN ALREADY: Although most of the studies which have examined risk of ASD after ART show no association, the results are mixed. Thus, further studies are needed to clarify this association. STUDY DESIGN SIZE, DURATION: The Upstate KIDS Study is a population-based, prospective cohort study of children born in New York State between 2008 and 2010. Children were screened for ASD using the Modified Checklist for Autism in Toddlers (M-CHAT) at ages 18 and 24 months. PARTICIPANTS/MATERIALS, SETTING, AND METHODS: The New York State live-birth registry was used to identify newborns conceived with and without fertility treatment with a 1:3 ratio, frequency matched on region of birth. At 18 and 24 months, 3183 and 3063 mothers, respectively, completed the M-CHAT questionnaire. The current analysis included 2586 singletons and 1296 twins with M-CHAT information at 18 and/or 24 months. Multivariable logistic regression with generalized estimating equations (GEE) was used to estimate odds ratios (aOR) and 95% confidence intervals (CI) after adjustment for covariates such as maternal age, education and plurality. MAIN RESULTS AND THE ROLE OF CHANCE: We found that 200 (5.2%) and 115 (3.0%) children failed the M-CHAT at 18 and 24 months, respectively. The associations between use of infertility treatment and failing the M-CHAT at 18 and/or 24 months were positive but inconclusive as they failed to exclude no association (18 months aOR 1.71, 95% CI: 0.81-3.61; 24 months aOR 1.78, 95% CI: 0.66-4.81; and both 18 and 24 months aOR 1.53, 95% CI: 0.78-2.99). The relationships between OI/IUI and ART with M-CHAT failure at 18 and/or 24 months were similar to those of using any fertility treatment. In vitro fertilization with intracytoplasmic sperm injection was not consistently positively or inversely associated with M-CHAT failure at each time point (18 months aOR 1.20, 95% CI: 0.51-2.83; 24 months aOR 0.93, 95% CI: 0.37-2.31; and both 18 and 24 months aOR 1.09, 95% CI: 0.50-2.60). LIMITATIONS REASONS FOR CAUTION: The M-CHAT is a screening tool used for ASD risk assessment, and therefore, M-CHAT failure does not indicate ASD diagnosis. In addition, we did not have power to detect associations of small magnitude. Finally, non-response to follow-up may bias the results. WIDER IMPLICATIONS OF THE FINDINGS: Despite lack of precision, the positive associations between ART and M-CHAT failure suggest that larger population-based studies with longer follow-up are needed. STUDY FUNDING/COMPETING INTEREST(S): Supported by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD; contracts HHSN275201200005C, HHSN267200700019C). The sponsor played no role in the study design, data collection, data analysis or interpretation, writing of the manuscript or decision to submit the article for publication. There are no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: Not applicable.

A 3-D Rat Brain Model for Blast-Wave Exposure: Effects of Brain Vasculature and Material Properties.

Exposure to blast waves is suspected to cause primary traumatic brain injury. However, existing finite-element (FE) models of the rat head lack the necessary fidelity to characterize the biomechanical responses in the brain due to blast exposure. They neglect to represent the cerebral vasculature, which increases brain stiffness, and lack the appropriate brain material properties characteristic of high strain rates observed in blast exposures. To address these limitations, we developed a high-fidelity three-dimensional FE model of a rat head. We explicitly represented the rat's cerebral vasculature and used high-strain-rate material properties of the rat brain. For a range of blast overpressures (100 to 230 kPa) the brain-pressure predictions matched experimental results and largely overlapped with and tracked the incident pressure-time profile. Incorporating the vasculature decreased the average peak strain in the cerebrum, cerebellum, and brainstem by 17, 33, and 18%, respectively. When compared with our model based on rat-brain properties, the use of human-brain properties in the FE model led to a three-fold reduction in the strain predictions. For simulations of blast exposure in rats, our findings suggest that representing cerebral vasculature and species-specific brain properties has a considerable influence in the resulting brain strain but not the pressure predictions.

Neurodevelopmental outcomes among extremely premature infants with linear growth restriction.

OBJECTIVE: To compare neurodevelopmental outcomes in linear growth-restricted (LGR) infants born <29 weeks with and without weight gain out of proportion to linear growth. STUDY DESIGN: We compared 2-year neurodevelopmental outcomes between infants with and without LGR and between LGR infants with and without weight gain out of proportion to linear growth. The outcomes were Bayley-III cognitive, motor, and language scores, cerebral palsy, Gross Motor Function Classification System (GMFCS) level ≥ 2, and neurodevelopmental impairment. RESULT: In total, 1227 infants were analyzed. LGR infants were smaller and less mature at birth, had higher BMI, and had lower Bayley-III language scores (82.3 vs. 85.0, p < 0.05). Among infants with LGR, infants with high BMI had lower language scores compared with those with low-to-normal BMI (80.8 vs. 83.3, p < 0.05), and were more likely to have GMFCS level ≥2 and neurodevelopmental impairment. CONCLUSION: Among infants with LGR, weight gain out of proportion to linear growth was associated with poorer neurodevelopmental outcomes.

Material Properties of Rat Middle Cerebral Arteries at High Strain Rates.

Traumatic brain injury (TBI), resulting from either impact- or nonimpact blast-related mechanisms, is a devastating cause of death and disability. The cerebral blood vessels, which provide critical support for brain tissue in both health and disease, are commonly injured in TBI. However, little is known about how vessels respond to traumatic loading, particularly at rates relevant to blast. To better understand vessel responses to trauma, the objective of this project was to characterize the high-rate response of passive cerebral arteries. Rat middle cerebral arteries (MCAs) were isolated and subjected to high-rate deformation in the axial direction. Vessels were perfused at physiological pressures and stretched to failure at strain rates ranging from approximately 100 to 1300 s-1. Although both in vivo stiffness and failure stress increased significantly with strain rate, failure stretch did not depend on rate.

Understanding and managing fish populations: keeping the toolbox fit for purpose.

Wild fish populations are currently experiencing unprecedented pressures, which are projected to intensify in the coming decades. Developing a thorough understanding of the influences of both biotic and abiotic factors on fish populations is a salient issue in contemporary fish conservation and management. During the 50th Anniversary Symposium of The Fisheries Society of the British Isles at the University of Exeter, UK, in July 2017, scientists from diverse research backgrounds gathered to discuss key topics under the broad umbrella of 'Understanding Fish Populations'. Below, the output of one such discussion group is detailed, focusing on tools used to investigate natural fish populations. Five main groups of approaches were identified: tagging and telemetry; molecular tools; survey tools; statistical and modelling tools; tissue analyses. The appraisal covered current challenges and potential solutions for each of these topics. In addition, three key themes were identified as applicable across all tool-based applications. These included data management, public engagement, and fisheries policy and governance. The continued innovation of tools and capacity to integrate interdisciplinary approaches into the future assessment and management of fish populations is highlighted as an important focus for the next 50 years of fisheries research.

Barriers to enrollment in a randomized controlled trial of hydrocortisone for cardiovascular insufficiency in term and late preterm newborn infants.

OBJECTIVE: To analyze reasons for low enrollment in a randomized controlled trial (RCT) of the effect of hydrocortisone for cardiovascular insufficiency on survival without neurodevelopmental impairment (NDI) in term/late preterm newborns. STUDY DESIGN: The original study was a multicenter RCT. Eligibility: ⩾34 weeks' gestation, <72 h old, mechanically ventilated, receiving inotrope. Primary outcome was NDI at 2 years; infants with diagnoses at high risk for NDI were excluded. This paper presents an analysis of reasons for low patient enrollment. RESULTS: Two hundred and fifty-seven of the 932 otherwise eligible infants received inotropes; however, 207 (81%) had exclusionary diagnoses. Only 12 infants were randomized over 10 months; therefore, the study was terminated. Contributing factors included few eligible infants after exclusions, open-label steroid therapy and a narrow enrollment window. CONCLUSION: Despite an observational study to estimate the population, very few infants were enrolled. Successful RCTs of emergent therapy may require fewer exclusions, a short-term primary outcome, waiver of consent and/or other alternatives.

Linkage of clinical trial and administrative data: a survey of cancer patient preferences.

BACKGROUND: Personal health information, including diagnoses and hospital admissions, is routinely collected in administrative databases. Patients enrolling on clinical trials consent to separate collection and storage of their personal health information. We evaluated patient preferences for linking long-term data from administrative databases with clinical trials. METHODS: Adults with cancer attending outpatient clinics at 3 Ontario hospitals were surveyed about their willingness, when faced with the hypothetical scenario of participating in a clinical trial, to provide potentially identifying information such as initials and date of birth to facilitate long-term research access to normally deidentified publicly collected databases. RESULTS: Of 569 patients surveyed, 335 (59%) were women, 452 (79%) were white, 385 (68%) had a post-secondary education, and 386 (68%) had never participated in a clinical trial. Median age in the group was 59 years. Most participants (93%, cohort 1) would allow long-term access to their information and allow personal information to be used to match clinical trial with administrative data. At the time of clinical trial closure, two thirds of participants (68%, cohort 2) preferred to make additional clinical information available through linkage with administrative databases, and 8 (9%) preferred to have no further information made available to researchers. No significant differences were found in the subset of patients who were part of a clinical trial and those who had never participated (p = 0.65). INTERPRETATION: Almost all patients would allow a clinical trial research team to access their confidential information, providing a more comprehensive assessment of an intervention's long-term risks and benefits.

Prolonged suppressive antibiotic therapy for prosthetic joint infection in the elderly: a national multicentre cohort study.

During prosthetic joint infection (PJI), optimal surgical management with exchange of the device is sometimes impossible, especially in the elderly population. Thus, prolonged suppressive antibiotic therapy (PSAT) is the only option to prevent acute sepsis, but little is known about this strategy. We aimed to describe the characteristics, outcome and tolerance of PSAT in elderly patients with PJI. We performed a national cross-sectional cohort study of patients >75 years old and treated with PSAT for PJI. We evaluated the occurrence of events, which were defined as: (i) local or systemic progression of the infection (failure), (ii) death and (iii) discontinuation or switch of PSAT. A total of 136 patients were included, with a median age of 83 years [interquartile range (IQR) 81-88]. The predominant pathogen involved was Staphylococcus (62.1%) (Staphylococcus aureus in 41.7%). A single antimicrobial drug was prescribed in 96 cases (70.6%). There were 46 (33.8%) patients with an event: 25 (18%) with an adverse drug reaction leading to definitive discontinuation or switch of PSAT, 8 (5.9%) with progression of sepsis and 13 died (9.6%). Among patients under follow-up, the survival rate without an event at 2 years was 61% [95% confidence interval (CI): 51;74]. In the multivariate Cox analysis, patients with higher World Health Organization (WHO) score had an increased risk of an event [hazard ratio (HR) = 1.5, p = 0.014], whereas patients treated with beta-lactams are associated with less risk of events occurring (HR = 0.5, p = 0.048). In our cohort, PSAT could be an effective and safe option for PJI in the elderly.

Cerebrovascular dysfunction following subfailure axial stretch.

Cerebral blood vessels are vital to maintaining the health of the brain. Traumatic brain injury (TBI) commonly results in autoregulatory dysfunction and associated failure of cerebral vessels to maintain homeostasis in the brain. While post-injury changes to brain biochemistry are known to contribute to this dysfunction, tissue deformation may also directly alter vascular smooth muscle cell (SMC) function. As a first step toward understanding stretch-induced dysfunction, this study investigates the effect of overstretch on the contractile behavior of SMCs in middle cerebral arteries (MCAs). We hypothesized that vessel function is altered above a threshold of stretch and strain rate. Twenty-four MCAs from Sprague Dawley rats were tested. Following development of basal SMC tone, vessels were subjected to increasing levels of isosmotic extracellular potassium (K+). Samples were then subjected to an axial overstretch of either 1.2*λIV or 1.3*λIV at strain rates of 0.2 or 20s-1. Following overstretch, SMC contractile behavior was measured again, both immediately and 60min after overstretch. Control vessels were subjected to the same protocol but without overstretch. SMC contractile behavior was characterized using both percent contraction (%C) relative to the fully dilated inner diameter and the K+ dose required to evoke the half maximal contractile response (EC50). Control vessels exhibited increased sensitivity to K+ in successive characterization tests, so all effects were quantified relative to the time-matched control response. Samples exhibited the typical biphasic response to extracellular K+, dilating and contracting in response to small and large K+ concentrations, respectively. As hypothesized, axial overstretch altered SMC contractile behavior, as seen in a decrease in %C for sub-maximal contractile K+ doses (p<0.05) and an increase in EC50 (p<0.01), but only for the test group stretched rapidly to 1.3*λIV. While the change in %C was only significantly different immediately after overstretch, the change to EC50 persisted for 60min. These results indicate that deformation can alter SMC contractile behavior and thus potentially play a role in cerebrovascular autoregulatory dysfunction independent of the pathological chemical environment in the brain post-TBI.