In Vitro Cell Culture Model for Osteoclast Activation during Estrogen Withdrawal.

Estrogen (17ß-estradiol) deficiency post-menopause alters bone homeostasis whereby bone resorption by osteoclasts exceeds bone formation by osteoblasts, leading to osteoporosis in females. We established an in vitro model to examine the consequences of estrogen withdrawal (E2-WD) on osteoclasts derived from the mouse macrophage RAW 264.7 cell line and utilized it to investigate the mechanism behind the enhanced osteoclast activity post-menopause. We found that a greater population of osteoclasts that underwent E2-WD contained a podosome belt necessary for osteoclasts to adhere and resorb bone and possessed elevated resorptive activity compared to osteoclasts exposed to estrogen (E2) continuously. Our results show that compared to osteoclasts that received E2 continuously, those that underwent E2-WD had a faster rate of microtubule (MT) growth, reduced RhoA activation, and shorter podosome lifespan. Thus, altered podosome and MT dynamics induced by the withdrawal of estrogen supports podosome belt assembly/stability in osteoclasts, which may explain their enhanced bone resorption activity.

From Habitat to Hormones: Year-around territorial behavior in rock-dwelling but not in forest and grassland lagomorphs and the role of DHEA.

Year-around defense of extremely patchy habitat may require hormones that drive territorial behavior, but have no other costly physiological effects. The American pika (Ochotona princeps), but not the snowshoe hare (Lepus americanus) nor the eastern cottontail rabbit (Sylvilagus floridanus), exhibits this behavior. The former engages in contest competition against all individuals independent of sex to protect its territory in highly fragmented patches on mountain talus slopes; the latter in scramble competition in more continuous forests, grasslands, and shrublands. The hormonal basis for this difference in lagomorphs is unknown. Dehydroepiandrosterone is a prohormone produced by the zona reticularis of the adrenal cortex. It has no effect on aggressive behavior until converted in the brain to estrogen. We assessed levels (DHEA-S plus DHEA) in all species collected in the wild. In nonbreeding pikas, levels were 256 times higher than in hares and 22 times higher than in rabbits. Within species, females and males had similar levels. The proportion of the adrenal cortex devoted to the zona reticularis was significantly larger in pikas than in hares or rabbits. Our evidence is consistent with the hypothesis that dehydroepiandrosterone drives this individual-based, year-around territoriality in pikas. We propose a definitive experiment to determine this and recommend comparative studies in central Asia where there is high diversity of pika species whose behavior ranges from individual-based territoriality to colonial. Thus, we speculate that the wild American pika has the adrenal-brain nexus for all seasons and is an excellent model to understand how habitat drives the hormonal control of spacing behavior.

Outcomes of Protocol-Driven Care of Critically Ill Severely Anemic Patients for Whom Blood Transfusion Is Not an Option.

OBJECTIVE: To compare the outcomes of severely anemic critically ill patients for whom transfusion is not an option ("bloodless" patients) with transfused patients. DESIGN: Cohort study with propensity score matching. SETTING: ICU of a referral center. PATIENTS: One hundred seventy-eight bloodless and 441 transfused consecutive severely anemic, critically ill patients, admitted between May 1996 and April 2011, and having at least one hemoglobin level less than or equal to 8 g/dL within 24 hours of ICU admission. Patients with diagnosis of brain injury, acute myocardial infarction, or status postcardiac surgery were excluded. INTERVENTIONS: Allogeneic RBC transfusion during ICU stay. MEASUREMENTS AND MAIN RESULTS: Primary outcome was in-hospital mortality. Other outcomes were ICU mortality, readmission to ICU, new electrocardiographic or cardiac enzyme changes suggestive of cardiac ischemia or injury, and new positive blood culture result. Transfused patients were older, had higher hemoglobin level at admission, and had higher Acute Physiology and Chronic Health Evaluation II score. Hospital mortality rates were 24.7% in bloodless and 24.5% in transfused patients (odds ratio, 1.01; 95% CI, 0.68-1.52; p = 0.95). Adjusted odds ratio of hospital mortality was 1.52 (95% CI, 0.95-2.43; p = 0.08). No significant difference in ICU readmission or positive blood culture results was observed. Analysis of propensity score-matched cohorts provided similar results. CONCLUSIONS: Overall risk of mortality in severely anemic critically ill bloodless patients appeared to be comparable with transfused patients, albeit the latter group had older age and higher Acute Physiology and Chronic Health Evaluation II score. Use of a protocol to manage anemia in these patients in a center with established patient blood management and bloodless medicine and surgery programs is feasible and likely to contribute to improved outcome, whereas more studies are needed to better delineate the impact of such programs.

Anthropometric Predictors of Heart Rate Variability in Overweight Individuals: A Comparative Study.

Introduction The autonomic nervous system is crucial in regulating cardiovascular function. Heart rate variability (HRV) analysis, a non-invasive method to assess autonomic function, reflects the beat-to-beat variations in heart rate and provides insights into the dynamic interplay between sympathetic and parasympathetic influences on the cardiovascular system. In this study, we aimed to find the HRV parameters in overweight individuals by comparing different anthropometric parameters, including body mass index (BMI), percentage body fat (%BF), waist circumference (WC), and waist-hip ratio (WHR). Method The descriptive cross-sectional study was conducted on 132 healthy first-year MBBS students (82 males and 50 females), aged between 17 and 23 years. Anthropometric parameters (BMI, %BF, WC, WHR) and HRV were recorded for the participants. The HRV parameters were analyzed for either gender. A student 't' test was used to test the difference between groups BMI <25 kg/m2 and = or >25 kg/m2, and a p-value less than 0.05 was taken to be statistically significant. The Pearson correlation coefficient was used to show the relationship between HRV parameters and BMI, %BF, WC, and WHR as the independent variables. Result A total of 132 healthy individuals participated in the study, including 82 males and 50 females. The participants had a mean age of 18.72 ± 0.98 years. Our results suggest that while WC and WHR can be used alongside BMI to indicate sympathetic hyperactivity in males, BMI remains the most significant predictor in females. We found gender-specific differences in high-frequency (HF) related to various anthropometric measures, but these differences were not statistically significant. The low-frequency:high-frequency (LF/HF) ratio exhibits strong positive correlations with all measured anthropometric parameters, suggesting that increased values in BMI, %BF, WC, and WHR are associated with greater sympathetic involvement. Conclusion WC and WHR, alongside BMI, are reliable indicators of heightened sympathetic activity in both males and females. These measures should be utilized to assess healthy individuals for the early diagnosis of dysautonomia, disrupt the cycle of sympathetic overactivity, and prevent cardiovascular complications. All these anthropometric parameters are valuable for indicating sympathovagal balance, making them essential tools in the proactive management of autonomic dysfunction and associated health risks.

Critical care physicians: attitudes, beliefs, and knowledge about pressure ulcers.

OBJECTIVE: The objective of this study was to determine critical care physicians' attitudes, beliefs, and knowledge toward pressure ulcer (PrU) prevention and treatment in critical care patients. DESIGN: Descriptive, correlational PARTICIPANTS: 56 critical care physicians MAIN OUTCOME MEASURES: Survey instrument developed to collect demographic information and information regarding attitudes and beliefs about PrUs and PrU knowledge. RESULTS: The majority of physicians (69%) reported poor to adequate basic medical education training on PrU prevention and treatment. Sixty percent reported never attending a PrU lecture. Most physicians reported their role to be important to very important in the areas of PrU prevention (71.4%) and treatment (67.9%). Physicians' perceived knowledge regarding PrU prevention and treatment was most frequently reported as adequate (48%) and poor (37%). The mean score on the knowledge test was 18.1 (range, 12-24; SD, 2.26), equating to a percentage score of 75%. No significant relationship was found between physicians' perceived PrU knowledge and actual knowledge score. CONCLUSIONS: Prevalence rates of acquired PrUs in critical care adult patients are cited as the highest among hospitalized patients; thus, critical care physicians encounter patients at risk for or with PrUs regularly in clinical practice. Management of a critically ill patient requires a cohesive, multidisciplinary approach, including prevention and/or management of PrUs. The critical care physician, as a vital member of this team, may benefit from PrU education in an effort to heighten awareness of this phenomenon in critical care patients.

An unusual case of orthodeoxia.

Progressive hypoxia in hospitalized patients can be due to many etiologies, especially in patients with multiple comorbidities. More unusual causes of hypoxia, such as patent foramen ovale (PFO) with a right to left shunting in the absence of elevated right atrial pressures, should be considered when workup does not reveal a specific etiology. .

Interventions to prevent skin cancer by reducing exposure to ultraviolet radiation: a systematic review.

The relationship between skin cancer and ultraviolet radiation is well established. Behaviors such as seeking shade, avoiding sun exposure during peak hours of radiation, wearing protective clothing, or some combination of these behaviors can provide protection. Sunscreen use alone is not considered an adequate protection against ultraviolet radiation. This report presents the results of systematic reviews of effectiveness, applicability, other harms or benefits, economic evaluations, and barriers to use of selected interventions to prevent skin cancer by reducing exposure to ultraviolet radiation. The Task Force on Community Preventive Services found that education and policy approaches to increasing sun-protective behaviors were effective when implemented in primary schools and in recreational or tourism settings, but found insufficient evidence to determine effectiveness when implemented in other settings, such as child care centers, secondary schools and colleges, and occupational settings. They also found insufficient evidence to determine the effectiveness of interventions oriented to healthcare settings and providers, media campaigns alone, interventions oriented to parents or caregivers of children, and community-wide multicomponent interventions. The report also provides suggestions for areas for future research.

Promoting informed decisions about cancer screening in communities and healthcare systems.

Individuals are increasingly involved in decisions about their health care. Shared decision making (SDM), an intervention in the clinical setting in which patients and providers collaborate in decision making, is an important approach for informing patients and involving them in their health care. However, SDM cannot bear the entire burden for informing and involving individuals. Population-oriented interventions to promote informed decision making (IDM) should also be explored. This review provides a conceptual background for population-oriented interventions to promote informed decisions (IDM interventions), followed by a systematic review of studies of IDM interventions to promote cancer screening. This review specifically asked whether IDM interventions (1) promote understanding of cancer screening, (2) facilitate participation in decision making about cancer screening at a level that is comfortable for individuals; or (3) encourage individuals to make cancer-screening decisions that are consistent with their preferences and values.Fifteen intervention arms met the intervention definition. They used small media, counseling, small-group education, provider-oriented strategies, or combinations of these to promote IDM. The interventions were generally consistent in improving individuals' knowledge about the disease, accuracy of risk perceptions, or knowledge and beliefs about the pros and cons of screening and treatment options. However, few studies evaluated whether these interventions resulted in individuals participating in decision making at a desirable level, or whether they led to decisions that were consistent with individuals' values and preferences. More research is needed on how best to promote and facilitate individuals' participation in health care. Work is especially needed on how to facilitate participation at a level desired by individuals, how to promote decisions by patients that are consistent with their preferences and values, how to perform effective and cost-effective IDM interventions for healthcare systems and providers and in community settings (outside of clinical settings), and how to implement these interventions in diverse populations (such as populations that are older, nonwhite, or disadvantaged). Finally, work is needed on the presence and magnitude of barriers to and harms of IDM interventions and how they might be avoided.

Angiotensin II stimulates alpha3(IV) collagen production in mouse podocytes via TGF-beta and VEGF signalling: implications for diabetic glomerulopathy.

BACKGROUND: The podocyte is bathed in an angiotensin II (AngII)-rich ultrafiltrate, but the impact of AngII on podocyte pathobiology is not well known. Because podocytes play a direct role in the glomerular basement membrane (GBM) thickening of diabetes, the alpha3(IV) collagen chain was examined. Podocyte expression of alpha3(IV) collagen may involve the transforming growth factor-beta (TGF-beta) and vascular endothelial growth factor (VEGF) systems. METHODS: Cultured mouse podocytes were treated with various doses of AngII for selected periods of time, with or without inhibitors of TGF-beta and VEGF signalling, SB-431542 and SU5416, respectively. TGF-beta1 and VEGF were assayed by enzyme-linked immunosorbent assay (ELISA); alpha3(IV) collagen, TGF-beta type II receptor and phospho-Smad2 were assayed by immunoblotting. RESULTS: AngII >or=10(-10) M was found to stimulate the production of alpha3(IV) collagen significantly in as short a time as 3 h. The expression of alpha3(IV) collagen was influenced by the TGF-beta system, but AngII did not increase the podocyte's production of TGF-beta1 ligand; rather, it increased the expression of the TGF-beta type II receptor and activated the TGF-beta signalling system through Smad2. Despite the TGF-beta receptor upregulation, synergy between AngII and TGF-beta1 to boost alpha3(IV) collagen production was not observed. However, blockade of TGF-beta signalling with SB-431542 prevented AngII from stimulating alpha3(IV) collagen production. Podocyte expression of alpha3(IV) collagen was also increased by the autocrine activity of VEGF. Podocytes were stimulated to secrete VEGF by 10(-10) M or higher AngII after 48 h. Blockade of the endogenous VEGF activity by SU5416 prevented AngII-stimulated alpha3(IV) collagen production. CONCLUSIONS: AngII stimulates the podocyte to produce alpha3(IV) collagen protein via mechanisms involving TGF-beta and VEGF signalling. Alterations in alpha3(IV) collagen production may contribute to GBM thickening and perhaps proteinuria in diabetes.