147 research outputs found

    Recognition and attractiveness as a function of sex and race

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    The present experiment replicated and refined.tests of. recognition memory for the human face. Three subject groups were used: White American females, White American males and Black African Malawian males. In part one, eighty monochromatic slides of Black and White American college seniors of both sexes were shown as (original) stimuli and then shown again with eighty new slides in a paired comparison task. An analysis of variance performed on the recognition scores revealed the following results: (a) A main effect for groups of slides with American females generating significantly fewer errors than the African males; (b) A main effect for race of slide with White slides generating fewer errors than Black slides for the American subjects; (c) A group by sex interaction with females recognizing female slides better than Black or White males, and male slides better than the Malawians; and (d) A group by race interaction with Whites recognizing White slides better than Black slides, and White males generating significantly fewer errors in recognizing White faces than did Malawian males. In part two, the same subjects rated 144 slides for attractiveness, on a scale of one to five. Spearman\u27s rank, order correlations were made between all pairs of groups on the attractiveness judgments for each sex and race of slide. Significant agreement.of attractiveness judgments was found for all sex/race categories by\u27American males and females, African males and American males judging Black male and female slides, and African males and American females judging Black male slides, Further, Spearman’s correlations between attractiveness judgments and recognizability of slide yielded two significant resultsi a positive correlation between recognizability and attractiveness for White males looking at White male slides, and a negative correlation for White females looking at Black female slides. An additional observation was that all White Americans overestimated the percentage of Blacks presently attending the University of Nebraska at Omaha

    Doubling the number of health graduates in Zambia: estimating feasibility and costs

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    <p>Abstract</p> <p>Background</p> <p>The Ministry of Health (MoH) in Zambia is operating with fewer than half of the human resources for health (HRH) necessary to meet basic population health needs. Responding urgently to address this HRH crisis, the MoH plans to double the annual number of health training graduates in the next five years to increase the supply of health workers. The feasibility and costs of achieving this initiative, however, are unclear.</p> <p>Methods</p> <p>We determined the feasibility and costs of doubling training institution output through an individual school assessment framework. Assessment teams, comprised of four staff from the MoH and Clinton Health Access Initiative, visited all of Zambia's 39 public and private health training institutions from 17 April to 19 June 2008. Teams consulted with faculty and managers at each training institution to determine if student enrollment could double within five years; an operational planning exercise carried out with school staff determined the investments and additional operating costs necessary to achieve expansion. Cost assumptions were developed using historical cost data.</p> <p>Results</p> <p>The individual school assessments affirmed the MoH's ability to double the graduate output of Zambia's public health training institutions. Lack of infrastructure was determined as a key bottleneck in achieving this increase while meeting national training quality standards. A total investment of US58.8millionisrequiredtomeetexpansioninfrastructureneeds,withUS 58.8 million is required to meet expansion infrastructure needs, with US 35.0 million (59.5%) allocated to expanding student accommodation and US23.8million(40.5 23.8 million (40.5%) allocated to expanding teaching, studying, office, and dining space. The national number of teaching staff must increase by 363 (111% increase) over the next five years. The additional recurring costs, which include salaries for additional teachers and operating expenses for new students, are estimated at US 58.0 million over the five-year scale-up period. Total cost of expansion is estimated at US$ 116.8 million over five years.</p> <p>Conclusions</p> <p>Historic underinvestment in training institutions has crippled Zambia's ability to meet expansion ambitions. There must be significant investments in infrastructure and faculty to meet quality standards while expanding training enrollment. Bottom-up planning can be used to translate national targets into costed implementation plans for expansion at each school.</p

    Muscle-Specific Loss of \u3cem\u3eBmal1\u3c/em\u3e Leads to Disrupted Tissue Glucose Metabolism and Systemic Glucose Homeostasis

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    Background: Diabetes is the seventh leading cause of death in the USA, and disruption of circadian rhythms is gaining recognition as a contributing factor to disease prevalence. This disease is characterized by hyperglycemia and glucose intolerance and symptoms caused by failure to produce and/or respond to insulin. The skeletal muscle is a key insulin-sensitive metabolic tissue, taking up ~80 % of postprandial glucose. To address the role of the skeletal muscle molecular clock to insulin sensitivity and glucose tolerance, we generated an inducible skeletal muscle-specific Bmal1 −/− mouse (iMSBmal1 −/−). Results: Progressive changes in body composition (decreases in percent fat) were seen in the iMSBmal1 −/− mice from 3 to 12 weeks post-treatment as well as glucose intolerance and non-fasting hyperglycemia. Ex vivo analysis of glucose uptake revealed that the extensor digitorum longus (EDL) muscles did not respond to either insulin or 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) stimulation. RT-PCR and Western blot analyses demonstrated a significant decrease in mRNA expression and protein content of the muscle glucose transporter (Glut4). We also found that both mRNA expression and activity of two key rate-limiting enzymes of glycolysis, hexokinase 2 (Hk2) and phosphofructokinase 1 (Pfk1), were significantly reduced in the iMSBmal1 −/− muscle. Lastly, results from metabolomics analyses provided evidence of decreased glycolytic flux and uncovered decreases in some tricarboxylic acid (TCA) intermediates with increases in amino acid levels in the iMSBmal1 −/− muscle. These findings suggest that the muscle is relying predominantly on fat as a fuel with increased protein breakdown to support the TCA cycle. Conclusions: These data support a fundamental role for Bmal1, the endogenous circadian clock, in glucose metabolism in the skeletal muscle. Our findings have implicated altered molecular clock dictating significant changes in altered substrate metabolism in the absence of feeding or activity changes. The changes in body composition in our model also highlight the important role that changes in skeletal muscle carbohydrate, and fat metabolism can play in systemic metabolism

    A Randomized Controlled Trial to Determine Whether Beta-Hydroxy-Beta-Methylbutyrate and/or Eicosapentaenoic Acid Improves Diaphragm and Quadriceps Strength in Critically Ill Mechanically Ventilated Patients

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    BACKGROUND: Intensive care unit acquired weakness is a serious problem, contributing to respiratory failure and reductions in ambulation. Currently, there is no pharmacological therapy for this condition. Studies indicate, however, that both beta-hydroxy-beta-methylbutyrate (HMB) and eicosapentaenoic acid (EPA) increase muscle function in patients with cancer and in older adults. The purpose of this study was to determine whether HMB and/or EPA administration would increase diaphragm and quadriceps strength in mechanically ventilated patients. METHODS: Studies were performed on 83 mechanically ventilated patients who were recruited from the Medical Intensive Care Units at the University of Kentucky. Diaphragm strength was assessed as the trans-diaphragmatic pressure generated by supramaximal magnetic phrenic nerve stimulation (PdiTw). Quadriceps strength was assessed as leg force generated by supramaximal magnetic femoral nerve stimulation (QuadTw). Diaphragm and quadriceps thickness were assessed by ultrasound. Baseline measurements of muscle strength and size were performed, and patients were then randomized to one of four treatment groups (placebo, HMB 3 gm/day, EPA 2 gm/day and HMB plus EPA). Strength and size measurements were repeated 11 days after study entry. ANCOVA statistical testing was used to compare variables across the four experimental groups. RESULTS: Treatments failed to increase the strength and thickness of either the diaphragm or quadriceps when compared to placebo. In addition, treatments also failed to decrease the duration of mechanical ventilation after study entry. CONCLUSIONS: These results indicate that a 10-day course of HMB and/or EPA does not improve skeletal muscle strength in critically ill mechanically ventilated patients. These findings also confirm previous reports that diaphragm and leg strength in these patients are profoundly low. Additional studies will be needed to examine the effects of other anabolic agents and innovative forms of physical therapy. TRIAL REGISTRATION: ClinicalTrials.gov, NCT01270516. Registered 5 January 2011, https://clinicaltrials.gov/ct2/show/NCT01270516?term=Supinski&draw=2&rank=4

    Age-Associated Disruption of Molecular Clock Expression in Skeletal Muscle of the Spontaneously Hypertensive Rat

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    It is well known that spontaneously hypertensive rats (SHR) develop muscle pathologies with hypertension and heart failure, though the mechanism remains poorly understood. Woon et al. (2007) linked the circadian clock gene Bmal1 to hypertension and metabolic dysfunction in the SHR. Building on these findings, we compared the expression pattern of several core-clock genes in the gastrocnemius muscle of aged SHR (80 weeks; overt heart failure) compared to aged-matched control WKY strain. Heart failure was associated with marked effects on the expression of Bmal1, Clock and Rora in addition to several non-circadian genes important in regulating skeletal muscle phenotype including Mck, Ttn and Mef2c. We next performed circadian time-course collections at a young age (8 weeks; pre-hypertensive) and adult age (22 weeks; hypertensive) to determine if clock gene expression was disrupted in gastrocnemius, heart and liver tissues prior to or after the rats became hypertensive. We found that hypertensive/hypertrophic SHR showed a dampening of peak Bmal1 and Rev-erb expression in the liver, and the clock-controlled gene Pgc1α in the gastrocnemius. In addition, the core-clock gene Clock and the muscle-specific, clock-controlled gene Myod1, no longer maintained a circadian pattern of expression in gastrocnemius from the hypertensive SHR. These findings provide a framework to suggest a mechanism whereby chronic heart failure leads to skeletal muscle pathologies; prolonged dysregulation of the molecular clock in skeletal muscle results in altered Clock, Pgc1α and Myod1 expression which in turn leads to the mis-regulation of target genes important for mechanical and metabolic function of skeletal muscle

    Temperature as a Circadian Marker in Older Human Subjects: Relationship to Metabolic Syndrome and Diabetes

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    Background: Circadian rhythms are characterized by approximate 24-hour oscillations in physiological and behavioral processes. Disruptions in these endogenous rhythms, most commonly associated with shift work and/or lifestyle, are recognized to be detrimental to health. Several studies have demonstrated a high correlation between disrupted circadian rhythms and metabolic disease. The aim of this study was to determine which metabolic parameters correlate with physiological measures of circadian temperature amplitude (TempAmp) and stability (TempStab). Methods: Wrist skin temperature was measured in 34 subjects (ages 50 to 70, including lean, obese, and diabetic subjects) every 10 minutes for 7 consecutive days. Anthropometric measures and fasting blood draws were conducted to obtain data on metabolic parameters: body mass index, hemoglobin A1C, triglycerides, cholesterol, high-density lipoprotein, and low-density lipoprotein. A history of hypertension and current blood pressure was noted. Results: Analysis of the data indicated a substantial reduction in TempAmp and TempStab in subjects with metabolic syndrome (three or more risk factors). To determine the impact of individual interdependent metabolic factors on temperature rhythms, stepwise multilinear regression analysis was conducted using metabolic syndrome measurements. Interestingly, only triglyceride level was consistently correlated by the analysis. Triglyceride level was shown to contribute to 33% of the variability in TempAmp and 23% of the variability in TempStab. Conclusion: Our results demonstrate that elevated triglycerides are associated with diminished TempAmp and TempStab in human subjects, and triglycerides may serve as a primary metabolic predictor of circadian parameters

    Cardiomyocyte Deletion of \u3ci\u3eBmal1\u3c/i\u3e Exacerbates QT- and RR-Interval Prolongation in \u3ci\u3eScn5a\u3c/i\u3e\u3csup\u3e+/ΔKPQ\u3c/sup\u3e Mice

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    Circadian rhythms are generated by cell autonomous circadian clocks that perform a ubiquitous cellular time-keeping function and cell type-specific functions important for normal physiology. Studies show inducing the deletion of the core circadian clock transcription factor Bmal1 in adult mouse cardiomyocytes disrupts cardiac circadian clock function, cardiac ion channel expression, slows heart rate, and prolongs the QT-interval at slow heart rates. This study determined how inducing the deletion of Bmal1 in adult cardiomyocytes impacted the in vivo electrophysiological phenotype of a knock-in mouse model for the arrhythmogenic long QT syndrome (Scn5a+/ΔKPQ). Electrocardiographic telemetry showed inducing the deletion of Bmal1 in the cardiomyocytes of mice with or without the ΔKPQ-Scn5a mutation increased the QT-interval at RR-intervals that were ≥130 ms. Inducing the deletion of Bmal1 in the cardiomyocytes of mice with or without the ΔKPQ-Scn5a mutation also increased the day/night rhythm-adjusted mean in the RR-interval, but it did not change the period, phase or amplitude. Compared to mice without the ΔKPQ-Scn5a mutation, mice with the ΔKPQ-Scn5a mutation had reduced heart rate variability (HRV) during the peak of the day/night rhythm in the RR-interval. Inducing the deletion of Bmal1 in cardiomyocytes did not affect HRV in mice without the ΔKPQ-Scn5a mutation, but it did increase HRV in mice with the ΔKPQ-Scn5a mutation. The data demonstrate that deleting Bmal1 in cardiomyocytes exacerbates QT- and RR-interval prolongation in mice with the ΔKPQ-Scn5a mutation

    Long QT Syndrome Type 2: Emerging Strategies for Correcting Class 2 \u3cem\u3eKCNH2 (hERG)\u3c/em\u3e Mutations and Identifying New Patients

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    Significant advances in our understanding of the molecular mechanisms that cause congenital long QT syndrome (LQTS) have been made. A wide variety of experimental approaches, including heterologous expression of mutant ion channel proteins and the use of inducible pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) from LQTS patients offer insights into etiology and new therapeutic strategies. This review briefly discusses the major molecular mechanisms underlying LQTS type 2 (LQT2), which is caused by loss-of-function (LOF) mutations in the KCNH2 gene (also known as the human ether-à-go-go-related gene or hERG). Almost half of suspected LQT2-causing mutations are missense mutations, and functional studies suggest that about 90% of these mutations disrupt the intracellular transport, or trafficking, of the KCNH2-encoded Kv11.1 channel protein to the cell surface membrane. In this review, we discuss emerging strategies that improve the trafficking and functional expression of trafficking-deficient LQT2 Kv11.1 channel proteins to the cell surface membrane and how new insights into the structure of the Kv11.1 channel protein will lead to computational approaches that identify which KCNH2 missense variants confer a high-risk for LQT2

    SerpinB2 deficiency in mice reduces bleeding times via dysregulated platelet activation

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    SerpinB2, also known as plasminogen activation inhibitor type 2 (PAI-2), is classically viewed as an inhibitor of fibrinolysis. However, we show herein a distinct, hitherto unrecognized role for SerpinB2 in hemostasis. Mice deficient in SerpinB2 expression and mice with an active site mutation in SerpinB2, both showed significant reductions in tail bleeding times. This hemostatic phenotype was associated with platelets, with SerpinB2 and SerpinB2-urokinase complexes clearly present in platelet fractions, and immunohistochemistry of blood clots suggesting SerpinB2 is associated with platelet aggregates. Thromboelastography illustrated faster onset of clot formation in blood from SerpinB2 deficient mice, whereas clotting of platelet-free plasma was unaffected. The results appear consistent with the low circulating SerpinB2 levels and hypercoagulation seen during pre-eclampsia; however, SerpinB2 was not detected in human platelets.This work was supported by the National Health and Medical Research Council of Australi
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