577 research outputs found

    Effect of Cytoskeletal Disruption on Mechanotransduction of Hydrostatic Pressure by C3H10T1/2 Murine Fibroblasts

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    Cyclic hydrostatic pressure of physiological magnitude (< 10 MPa) stimulates chondrogenic differentiation of mesenchymal stem cells, but mechanotransduction mechanisms are not well understood. It was hypothesized that an intact cytoskeleton would be required for uninhibited mechanotransduction of hydrostatic pressure. Therefore we examined the effects of drugs which selectively interfere with actin and tubulin polymerization on pressure-induced upregulation of aggrecan and col2a1 (type II collagen) mRNA expression. C3H10T1/2 cells were cultured as pellets in either 4µM cytochalasin D or 4µM nocodazole and subjected to 3 days of cyclic hydrostatic compression (1 Hz, 5 MPa, 2 h per day). Phalloidin staining and indirect immunostaining with anti α-tubulin antibody confirmed disruption of microfilament and microtubule assemblies, respectively. Real time RT-PCR revealed that both drugs substantially lowered the basal level of aggrecan and col2a1 mRNA, but that neither drug prevented a pressure-stimulated increase in gene expression relative to the altered basal state. Thus upregulation of macromolecular gene expression by cyclic hydrostatic pressure did not require a completely intact cytoskeleton

    Tension-Compression Loading with Chemical Stimulation Results in Additive Increases to Functional Properties of Anatomic Meniscal Constructs

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    Objective: This study aimed to improve the functional properties of anatomically-shaped meniscus constructs through simultaneous tension and compression mechanical stimulation in conjunction with chemical stimulation. Methods: Scaffoldless meniscal constructs were subjected to simultaneous tension and compressive stimulation and chemical stimulation. The temporal aspect of mechanical loadingwas studied by employing two separate five day stimulation periods. Chemical stimulation consisted of the application of a catabolic GAG-depleting enzyme, chondroitinase ABC (C-ABC), and an anabolic growth factor, TGF-b1. Mechanical and chemical stimulation combinations were studied through a full-factorial experimental design and assessed for histological, biochemical, and biomechanical properties following 4 wks of culture. Results: Mechanical loading applied from days 10–14 resulted in significant increases in compressive, tensile, and biochemical properties of meniscal constructs. When mechanical and chemical stimuliwere combined significant additive increases in collagen per wet weight (4-fold), compressive instantaneous (3-fold) and relaxation (2-fold) moduli, and tensile moduli in the circumferential (4-fold) and radial (6-fold) directions were obtained. Conclusions: This study demonstrates that a stimulation regimen of simultaneous tension and compression mechanical stimulation, C-ABC, and TGF-b1 is able to create anatomic meniscus constructs replicating the compressive mechanica

    The academic backbone: longitudinal continuities in educational achievement from secondary school and medical school to MRCP(UK) and the specialist register in UK medical students and doctors

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    Background: Selection of medical students in the UK is still largely based on prior academic achievement, although doubts have been expressed as to whether performance in earlier life is predictive of outcomes later in medical school or post-graduate education. This study analyses data from five longitudinal studies of UK medical students and doctors from the early 1970s until the early 2000s. Two of the studies used the AH5, a group test of general intelligence (that is, intellectual aptitude). Sex and ethnic differences were also analyzed in light of the changing demographics of medical students over the past decades. Methods: Data from five cohort studies were available: the Westminster Study (began clinical studies from 1975 to 1982), the 1980, 1985, and 1990 cohort studies (entered medical school in 1981, 1986, and 1991), and the University College London Medical School (UCLMS) Cohort Study (entered clinical studies in 2005 and 2006). Different studies had different outcome measures, but most had performance on basic medical sciences and clinical examinations at medical school, performance in Membership of the Royal Colleges of Physicians (MRCP(UK)) examinations, and being on the General Medical Council Specialist Register. Results: Correlation matrices and path analyses are presented. There were robust correlations across different years at medical school, and medical school performance also predicted MRCP(UK) performance and being on the GMC Specialist Register. A-levels correlated somewhat less with undergraduate and post-graduate performance, but there was restriction of range in entrants. General Certificate of Secondary Education (GCSE)/O-level results also predicted undergraduate and post-graduate outcomes, but less so than did A-level results, but there may be incremental validity for clinical and post-graduate performance. The AH5 had some significant correlations with outcome, but they were inconsistent. Sex and ethnicity also had predictive effects on measures of educational attainment, undergraduate, and post-graduate performance. Women performed better in assessments but were less likely to be on the Specialist Register. Non-white participants generally underperformed in undergraduate and post-graduate assessments, but were equally likely to be on the Specialist Register. There was a suggestion of smaller ethnicity effects in earlier studies. Conclusions: The existence of the Academic Backbone concept is strongly supported, with attainment at secondary school predicting performance in undergraduate and post-graduate medical assessments, and the effects spanning many years. The Academic Backbone is conceptualized in terms of the development of more sophisticated underlying structures of knowledge ('cognitive capital’ and 'medical capital’). The Academic Backbone provides strong support for using measures of educational attainment, particularly A-levels, in student selection

    Genetic diversity of Brazilian isolates of feline immunodeficiency virus

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    We isolated Feline immunodeficiency virus (FIV) from three adult domestic cats, originating from two open shelters in Brazil. Viruses were isolated from PBMC following co-cultivation with the feline T-lymphoblastoid cell line MYA-1. All amplified env gene products were cloned directly into pGL8MYA. The nucleic acid sequences of seven clones were determined and then compared with those of previously described isolates. The sequences of all of the Brazilian virus clones were distinct and phylogenetic analysis revealed that all belong to subtype B. Three variants isolated from one cat and two variants were isolated from each of the two other cats, indicating that intrahost diversity has the potential to pose problems for the treatment and diagnosis of FIV infection

    Particulate Matter (PM) Research Centers (1999–2005) and the Role of Interdisciplinary Center-Based Research

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    Objective: The U.S. Environmental Protection Agency funded five academic centers in 1999 to address the uncertainties in exposure, toxicity, and health effects of airborne particulate matter (PM) identified in the “Research Priorities for Airborne Particulate Matter” of the National Research Council (NRC). The centers were structured to promote interdisciplinary approaches to address research priorities of the NRC. In this report, we present selected accomplishments from the first 6 years of the PM Centers, with a focus on the advantages afforded by the interdisciplinary, center-based research approach. The review highlights advances in the area of ultrafine particles and traffic-related health effects as well as cardiovascular and respiratory effects, mechanisms, susceptibility, and PM exposure and characterization issues. Data sources and synthesis: The collective publications of the centers served as the data source. To provide a concise synthesis of overall findings, authors representing each of the five centers identified a limited number of topic areas that serve to illustrate the key accomplishments of the PM Centers program, and a consensus statement was developed. Conclusions: The PM Centers program has effectively applied interdisciplinary research approaches to advance PM science

    Personality trait development in midlife: exploring the impact of psychological turning points

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    This study examined long-term personality trait development in midlife and explored the impact of psychological turning points on personality change. Selfdefined psychological turning points reflect major changes in the ways people think or feel about an important part of their life, such as work, family, and beliefs about themselves and about the world. This study used longitudinal data from the Midlife in the US survey to examine personality trait development in adults aged 40–60 years. The Big Five traits were assessed in 1995 and 2005 by means of self-descriptive adjectives. Seven types of self-identified psychological turning points were obtained in 1995. Results indicated relatively high stability with respect to rankorders and mean-levels of personality traits, and at the same time reliable individual differences in change. This implies that despite the relative stability of personality traits in the overall sample, some individuals show systematic deviations from the sample mean-levels. Psychological turning points in general showed very little influence on personality trait change, although some effects were found for specific types of turning points that warrant further research, such as discovering that a close friend or relative was a much better person than one thought they were

    Parental health limitations, caregiving and loneliness among women with widowed parents: longitudinal eveidence from France

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    We investigate how daughters’ feelings of loneliness are impacted when widowed parents develop health limitations, and when daughters take on personal care tasks in response. Using longitudinal data from daughters of widowed parents drawn from the French Family and Intergenerational Relationships Study (ERFI, 1485 observations nested in 557 daughters), we assess (a) whether health limitations of widowed parents are associated with daughters’ feelings of loneliness regardless of whether or not daughters provide personal care and (b) whether there is an effect of care provision on loneliness that cannot be explained by parental health limitations. Fixed effect regression analyses show that widowed parents’ health limitations were associated with raised feelings of loneliness among their daughters. No significant additional effect of providing personal care to a widowed parent was found. Prior research on the impact of health limitations of older parents on the lives of their adult–children has focused mostly on issues related to informal caregiving. Our findings suggest that more attention to the psychosocial impact of parental health limitations—net of actual caregiving—on adult children’s lives is warranted

    Enhanced Eyelashes: Prescription and Over-the-Counter Options

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    Women have long strived to possess long, thick, and dark eyelashes. Prominent eyes and eyelashes are often considered a sign of beauty and can be associated with increased levels of attractiveness, confidence, and well-being. Numerous options may improve the appearance of eyelashes. Mascara aims to temporarily darken, lengthen, and thicken eyelashes using a combination of waxes, pigments, and resins. Artificial eyelashes can be adhered either to the dermal margin or to individual eyelashes. Individuals may even use eyelash transplantations to improve the appearance of their eyelashes. The unique properties of eyelashes (e.g., relatively long telogen and short anagen phases compared with scalp hairs, slow rate of growth, and a lack of influence by androgens) may allow for specific aesthetic interventions to improve the appearance of natural eyelashes. Some over-the-counter (OTC) products may contain prostaglandin analogs that can affect eyelash growth, but neither the safety nor efficacy of these OTC cosmetics has been fully studied. Originally indicated for the reduction of intraocular pressure, the synthetic prostaglandin analog bimatoprost was recently approved for the treatment of hypotrichosis of the eyelashes. In a double-blinded, randomized, vehicle-controlled trial, bimatoprost safely and effectively grew natural eyelashes, making them longer, thicker, and darker. Bimatoprost was generally safe and well tolerated and appears to provide an additional option for individuals looking to improve the appearance of their eyelashes

    What is new in surgical treatment of vesicoureteric reflux?

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    In addition to conventional open surgery and endoscopic techniques, laparoscopic correction of vesicoureteric reflux, sometimes even robot-assisted, is becoming an alternative surgical treatment modality for this condition in a number of centres around the world. At least for a subgroup of patients laparoscopists are trying to develop new techniques in an effort to combine the best of both worlds: the minimal invasiveness of the STING and the same lasting effectiveness as in open surgery. The efficacy and potential advantages or disadvantages of these techniques are still under investigation. The different laparoscopic techniques and available data are presented
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