No abstract

ABSTRACT. The mechanism of heat extraction from the lower oceanic crust near the ridge axis is poorly constrained despite its importance for understanding both the process of accretion of the plutonic complex and the mass fluxes associated with ridge hydrothermal systems.

There is disagreement in the literature as to whether biological attribution increases or decreases stigma. This study investigated the effect of an online biological intervention on stigma and help-seeking intentions for depression among adolescents. A three-arm, pre-post test, double-blind randomised controlled trial (RCT) was used to compare the effects of a biological and a psychosocial intervention delivered online. Participants comprised secondary school students (N = 327) aged 16-19 years. Outcome measures included anticipated self-stigma for depression (primary), personal stigma, help-seeking intention for depression, and biological and psychosocial attribution. Neither the biological nor the psychosocial educational intervention significantly reduced anticipated self-stigma or personal stigma for depression relative to the control. However, a small increase in help-seeking intention for depression relative to the control was found for the biological educational condition. The study was undertaken over a single session and it is unknown whether the intervention effect on help-seeking intentions was sustained or would translate into help-seeking behaviour. A brief online biological education intervention did not alter stigma, but did promote a small increase in help-seeking intentions for depression among adolescents. This type of intervention may be a practical means for facilitating help-seeking among adolescents with current or future depression treatment needs.

Adolescence is a critical developmental period. An important change that occurs in adolescence is the neurological maturation for adult-type cognitive abilities. Research has linked adequate sleep quantity to successful learning and memory capabilities. However, due to a shift in sleep timing drive in adolescence, in combination with early awakening for school, the adolescent population is experiencing chronic sleep restriction (CSR). What repercussions to long-term memory capabilities could CSR in adolescence have immediately and are the consequences longlasting? The present study modeled human adolescent CSR in rats through four hours of sleep deprivation for five days, followed by two days of unrestricted sleep, and five more days of four hours of sleep deprivation; thus the rats were exposed to CSR throughout the two-week rat adolescent period. Long-term hippocampal dependent and non-hippocampal dependent memory were tested through the object location task and the object recognition task, respectively. Testing occurred in adolescence and after a four-week delay during which the rats slept freely and matured to adulthood. The results showed that, given the appropriate conditions for successful long-term memory, the rats exposed to CSR in adolescence showed impaired hippocampal dependent memory in adolescence and this impairment was also evident in adulthood. These findings were not the case for non-hippocampal dependent memory, for which a significant effect of sleep was not found. Given the findings of the hippocampal dependent task, these results suggest that CSR in adolescence may influence less than optimal memory performance among adolescents. Further, the pattern in adulthood suggests that even after undisturbed sleep in the period from adolescence to adult maturation, the consequences of adolescent CSR are relentless. The findings in this study inform the research as the first rodent model of adolescent CSR and indicate practical implications for the health of adolescents.

Background Although efforts to treat hepatitis C virus (HCV) in people who inject drugs (PWID) yield high rates of sustained virologic response (SVR), the relationship between successful HCV treatment and health-related quality of life (HRQOL) among PWID is poorly understood. This study examined HRQOL changes throughout HCV treatment and post-treatment for PWID achieving SVR. Methods Participants included 141 PWID who achieved SVR following HCV treatment onsite at three opioid agonist treatment (OAT) clinics in Bronx, NY. The EQ-5D-3L assesses five health dimensions (mobility, self-care, usual activities, pain/discomfort, anxiety/depression), producing an index of HRQOL ranging from 0-1. EQ-5D-3L was measured at baseline, 4-, 8-, and 12-weeks during treatment and 12- and 24-weeks post-treatment. Linear mixed effects regression models were used to assess changes in the mean EQ-5D-3L index over time. Results Mean EQ-5D-3L index baseline was 0.66 (SE=0.02). Whereas over half the population reported no baseline problems with self-care (85.1%), usual activities (56.0%), and mobility (52.5%), at least two-thirds reported problems with pain/discomfort (78.0%) and anxiety/depression (66.0%), with 22.0% and 21.3% reporting extreme problems for pain/discomfort and anxiety/depression, respectively. Twenty-four weeks post-treatment, proportions reporting pain/discomfort and anxiety/depression decreased by 25.7% and 24.0%, respectively. The mean EQ-5D-3L index significantly improved during treatment (p<0.0001), and improvement was sustained following treatment completion, with mean EQ-5D-3L index of 0.77 (SE=0.02) 12-weeks post-SVR. Conclusions HCV treatment led to sustained improvement in HRQOL for PWID on OAT who achieved SVR. Future research is necessary to determine whether improvements in HRQOL can be sustained beyond 12-weeks post-SVR.

Objective: Claudication is an early-stage subtype of peripheral artery disease that may result in surgical intervention. The purpose of this study was to compare the types of elective bypass in a population of Black and White patients with claudication and to identify actionable areas that may explain the higher limb amputation rates observed in Black patients. Methods: We identified Black and White patients undergoing elective infrainguinal bypass for claudication using data from the Vascular Quality Initiative registry (2011-2018). Distal bypass target was classified as 1) at or above the popliteal artery (above-knee) or 2) below the popliteal, including all tibial, peroneal, dorsalis pedis and tarsal/plantar arteries (below-knee). Graft conduit was categorized as vein or prosthetic. We calculated one-year risk of major lower limb amputation with 95% confidence intervals (CI) for all combinations of target and conduit, stratified by race. We then forced an intervention on the data to estimate the post-intervention incidence of amputation and the proportion of racial disparity eliminated and 95% CI if everyone received the gold standard treatment (above-knee, vein). Results: We identified 8,401 infrainguinal bypass revascularizations for claudication (12% Black/88% White); 82% were performed above-knee and 44% of those used a vein conduit. The remaining 18% of bypasses were to below-knee arteries, of which 78% used a vein conduit. The remaining 1,534 (18.3%) bypasses were to below-knee arteries, including 1,197 (78.4%) using vein and 330 (21.6%) using prosthetic material. One-year incidence of major limb amputation was 1.6% (1.3%,1.9%) among all grafts, 1.2% (1.0%,1.5%) in above-knee grafts, and 3.3% (2.4%,4.2%) in below-knee grafts. Black patients had higher incidence of amputation across bypass target/conduit groups compared to White patients; the difference was greatest for below-knee revascularizations (8.9%, 95% CI: 4.8%,12.3% v 2.1%, 95% CI: 0.9%,2.9%). Pre-intervention amputation incidence was 1.3% (1.0%,1.5%) in White patients and 3.6% (1.9%,5.2%) in Black patients. Overall amputation incidence decreased significantly after our gold standard intervention was applied for both White (1.0%; 0.7%,1.2%) and Black (2.0%; 0.7%,3.2%) patients. The risk difference (i.e. the disparity gap) between Black and White patients was lessened post-intervention by 56.8% (31.9%,116.3%). Conclusions: We observed risk of amputation higher than would be expected based on other studies of the natural history of claudication without bypass surgery; future work should identify the mechanisms that alter the natural history of claudication via open bypass surgery. Interventions below-knee or using a prosthetic graft were particularly harmful and their harm was concentrated in Black patients.

Background. People undergoing revascularization for symptomatic peripheral artery disease (PAD) have a high incidence of major limb amputation in the year following their surgical procedure. The incidence of limb amputation is particularly high in patients from racial and ethnic minority groups. The purpose of our study was to investigate the role of sub-optimal prescription of preoperative antiplatelets and statins in producing disparities in risk of major amputation following revascularization for symptomatic PAD. Methods. We used data from adult (≥18 years old) patients in the Vascular Quality Initiative (VQI) registry who underwent a revascularization procedure from 2011-2018. Patients were categorized as non-Hispanic Black, non-Hispanic White, and Hispanic. We estimated the crude probability of a patient being prescribed a preoperative antiplatelet and preoperative statin. We calculated one year risk incidence of amputation by prescription groups and by race/ethnicity. We estimated the amputation risk difference between race/ethnicity groups (the proportion of disparity) that could be eliminated under a hypothetical intervention where a pre-operative antiplatelet and statin was provided to all patients. Results. Across 100,579 revascularizations recorded in the Vascular Quality Initiative, a vascular procedure-based registry in the United States and Canada, 1-year risk of amputation was 2.5% (95% CI: 2.4%,2.6%) in White patients, 5.3% (4.9%,5.6%) in Black patients and 5.3% (4.7%,5.9%) in Hispanic patients. Black (57.5%) and Hispanic patients (58.7%) were only slightly less likely than White patients (60.9%) to receive recommended antiplatelet and statin therapy prior to their procedures. However, the effect of antiplatelets and statins was greater in Black and Hispanic patients such that, had all patients received the appropriate guideline recommended medications, the estimated risk difference comparing Black to White patients would have reduced by 8.9% (-2.9%,21.9%) and the risk difference comparing Hispanic to White patients would have been reduced by 17.6% (-0.7%,38.6%). Conclusions. Even though guideline-based care appeared evenly distributed by race/ethnicity, increasing access to such care may still decrease health care disparities in major limb amputation.

No abstract