204 research outputs found
Milieu-adopted in vitro and in vivo differentiation of mesenchymal tissues derived from different adult human CD34-negative progenitor cell clones
Adult mesenchymal stem cells with multilineage differentiation potentially exist in the bone marrow, but have also been isolated from the peripheral blood. The differentiation of stem cells after leaving their niches depends predominately on the local milieu and its new microenvironment, and is facilitated by soluble factors but also by the close cell-cell interaction in a three-dimensional tissue or organ system. We have isolated CD34-negative, mesenchymal stem cell lines from human bone marrow and peripheral blood and generated monoclonal cell populations after immortalization with the SV40 large T-antigen. The cultivation of those adult stem cell clones in an especially designed in vitro environment, including self-constructed glass capillaries with defined growth conditions, leads to the spontaneous establishment of pleomorphic three-dimensional cell aggregates ( spheroids) from the monoclonal cell population, which consist of cells with an osteoblast phenotype and areas of mineralization along with well-vascularized tissue areas. Modifications of the culture conditions favored areas of bone-like calcifications. After the transplantation of the at least partly mineralized human spheroids into different murine soft tissue sites but also a dorsal skinfold chamber, no further bone formation could be observed, but angiogenesis and neovessel formation prevailed instead, enabling the transplanted cells and cell aggregates to survive. This study provides evidence that even monoclonal adult human CD34-negative stem cells from the bone marrow as well as peripheral blood can potentially differentiate into different mesenchymal tissues depending on the local milieu and responding to the needs within the microenvironment. Copyright (C) 2005 S. Karger AG, Basel
Quantitative assessment of angiogenesis in murine antigen-induced arthritis by intravital fluorescence microscopy
Inhibition of angiogenesis might be a therapeutic approach to prevent joint destruction caused by the overgrowing synovial tissue during chronic joint inflammation. The aim of this study was to investigate angiogenesis in the knee joint of mice with antigen-induced arthritis (AIA) by means of intravital microscopy. In 14 mice (C57BL6/129Sv) intravital microscopic assessment was performed on day 8 after AIA induction in two groups (controls, AIA). Synovial tissue was investigated by intravital fluorescence microscopy using FITC-dextran (150 kD). Quantitative assessment of vessel density was performed according to the following categories: functional capillary density (FCD, vessels 10 mum) and FVD of vessels with angiogenic criteria (convoluted vessels, abrupt changes of diameter, vessels which are generated by sprouting and progressively pruned and remodelled). Microvessel count was performed using immunohistochemistry. There was no significant difference in FCD between the control group (337 +/- 9 cm/cm(2); mean +/-SEM) and the AIA group (359 +/- 13 cm/cm(2)). The density of vessels larger than 10 gm diameter was significantly increased in animals with AIA (135 +/- 10 vs. 61 +/- 5 cm/cm(2) in control). The density of blood vessels with angiogenic criteria was enhanced in arthritic animals (79 +/- 17 vs. 12 +/- 2 cm/cm(2) in control). There was a significant increase in the microvessel count in arthritic animals (297 +/- 25 vs. 133 +/- 16 mm(-2) in control). These findings demonstrate that angiogenesis in murine AIA can be assessed quantitatively using intravital microscopy. Further studies will address antiangiogenic strategies in AIA
Development and Testing of the Dysmenorrhea Symptom Interference (DSI) Scale
Dysmenorrhea affects most reproductive-age women and increases the risk of future pain. To evaluate dysmenorrhea interventions, validated outcome measures are needed. In this two-phase study, we developed and tested the dysmenorrhea symptom interference scale. During the scale-development phase (n = 30), we created a nine-item scale based on qualitative data from cognitive interviews. During the scale-testing phase (n = 686), we evaluated reliability, validity, and responsiveness to change. The scale measures how dysmenorrhea symptoms interfere with physical, mental, and social activities. Internal consistency was strong with Cronbach's α > 0.9. Test-retest reliability was acceptable (r = 0.8). The scale showed satisfactory content validity, construct validity (supported by confirmatory factor analysis), concurrent validity, and responsiveness to change. The minimally important difference was 0.3 points on a scale with a possible total score ranging from 1 to 5. This new psychometrically sound scale can be used in research and clinical practice to facilitate the measurement and management of dysmenorrhea
Исследование возможности применения технологии сохранения трехмерных объектов для ракетно-космической промышленности
Ascites due to right atrial myxoma in a haemodialysis patient
BACKGROUND: Persistent fluid overload in patients on renal replacement therapy despite good dialysis adequacy or obvious cardiac dysfunction should prompt a search for rarer causes. CASE PRESENTATION: We report here a rare cause of persistent peripheral oedema and ascites in a well-dialysed patient. CT scanning revealed a right atrial myxoma that was later confirmed on an echocardiogram. CONCLUSION: Fluid overload states are common in patients on dialysis. Common causes are inadequacy of dialysis and non-compliance. Where aetiology is not easily apparent further investigations into rarer causes should be sought
Measuring research mistrust in adolescents and adults: Validity and reliability of an adapted version of the Group-Based Medical Mistrust Scale
Mistrust of health care providers among persons of color is a significant barrier to engaging them in research studies. Underrepresentation of persons of color is particularly problematic when the health problem under study disproportionately affects minoritized communities. The purpose of this study was to test the validity and reliability of an abbreviated and adapted version of the Group Based Medical Mistrust Scale. The GBMMS is a 12-item scale with three subscales that assess suspicion, experiences of discrimination, and lack of support in the health care setting. To adapt for use in the research setting, we shortened the scale to six items, and replaced "health care workers" and "health care" with "medical researchers" and "medical research," respectively. Using panelists from a market research firm, we recruited and enrolled a racially and ethnically diverse sample of American adults (N = 365) and adolescents aged 14-17 (N = 250). We administered the adapted scale in a web-based survey. We used Cronbach's alpha to evaluate measure internal reliability of the scale and external factor analysis to evaluate the relationships between the revised scale items. Five of the six items loaded onto a single factor, with (α = 0.917) for adolescents and (α = 0.912) for adults. Mean scores for each item ranged from 2.5-2.9, and the mean summary score (range 6-25) was 13.3 for adults and 13.1 for adolescents. Among adults, Black respondents had significantly higher mean summary scores compared to whites and those in other racia/ethnic groups (p<0.001). There was a trend toward significance for Black adolescents as compared to white respondents and those in other racial/ethnic groups (p = 0.09). This five-item modified version of the GBMMS is reliable and valid for measuring research mistrust with American adults and adolescents of diverse racial and ethnic identities
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