1000 resultados para bone bank


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Background: Interest in the prevention of osteoporosis is increasing and thus there is a need for an acceptable osteoporosis prevention programme in general practice. AIM. A study was undertaken to identify a cohort of middle-aged women attending a general practice who would be eligible for a longitudinal study looking at bone mineral density, osteoporosis and the effectiveness of hormone replacement therapy. This study aimed to describe the relationship between medical and lifestyle risk factors for osteoporosis and the initial bone density measurements in this group of women. METHOD. A health visitor administered a questionnaire to women aged between 48 and 52 years registered with a Belfast general practice. The main outcome measures were menopausal status, presence of medical and lifestyle risk factors and bone mineral density measurements. RESULTS. A total of 358 women our of 472 (76%) took part in the study which was conducted in 1991 and 1992. A highly significant difference was found between the mean bone mineral density of premenopausal, menopausal and postmenopausal women within the narrow study age range, postmenopausal women having the lowest bone mineral density. A significant relationship was found between body mass index and bone mineral density, a greater bone mineral density being found among women with a higher body mass index. Risk factors such as smoking and sedentary lifestyle were common (reported by approximately one third of respondents) but a poor relationship was found between these two and all the other risk factors and bone mineral density in this age group. CONCLUSION. Risk of osteoporosis cannot be identified by the presence of risk factors in women aged between 48 and 52 years. In terms of a current prevention strategy for general practice it would be better to take a population-based approach except for those women known to be at high risk of osteoporosis: women with early menopause or those who have had an oophorectomy.

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We investigated the phenotype of cells involved in leukostasis in the early stages of streptozotocin-induced diabetes in mice by direct observation and by adoptive transfer of calcein-AM-labeled bone marrow-derived leukocytes from syngeneic mice. Retinal whole mounts, confocal microscopy, and flow cytometry ex vivo and scanning laser ophthalmoscopy in vivo were used. Leukostasis in vivo and ex vivo in retinal capillaries was increased after 2 weeks of diabetes (Hb A(1c), 14.2 ± 1.2) when either donor or recipient mice were diabetic. Maximum leukostasis occurred when both donor and recipient were diabetic. CD11b(+), but not Gr1(+), cells were preferentially entrapped in retinal vessels (fivefold increase compared with nondiabetic mice). In diabetic mice, circulating CD11b(+) cells expressed high levels of CCR5 (P = 0.04), whereas spleen (P = 0.0001) and retinal (P = 0.05) cells expressed increased levels of the fractalkine chemokine receptor. Rosuvastatin treatment prevented leukostasis when both recipient and donor were treated but not when donor mice only were treated. This effect was blocked by treatment with mevalonate. We conclude that leukostasis in early diabetic retinopathy involves activated CCR5(+)CD11b(+) myeloid cells (presumed monocytes). However, leukostasis also requires diabetes-induced changes in the endothelium, because statin therapy prevented leukostasis only when recipient mice were treated. The up-regulation of the HMG-CoA reductase pathway in the endothelium is the major metabolic dysregulation promoting leukostasis.

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Transplantation of hepatocytes or hepatocyte-like cells of extrahepatic origin is a promising strategy for treatment of acute and chronic liver failure. We examined possible utility of hepatocyte-like cells induced from bone marrow cells for such a purpose. Clonal cell lines were established from the bone marrow of two different rat strains. One of these cell lines, rBM25/S3 cells, grew rapidly (doubling time, approximately 24 hours) without any appreciable changes in cell properties for at least 300 population doubling levels over a period of 300 days, keeping normal diploid karyotype. The cells expressed CD29, CD44, CD49b, CD90, vimentin, and fibronectin but not CD45, indicating that they are of mesenchymal cell origin. When plated on Matrigel with hepatocyte growth factor and fibroblast growth factor-4, the cells efficiently differentiated into hepatocyte-like cells that expressed albumin, cytochrome P450 (CYP) 1A1, CYP1A2, glucose 6-phosphatase, tryptophane-2,3-dioxygenase, tyrosine aminotransferase, hepatocyte nuclear factor (HNF)1 alpha, and HNF4alpha. Intrasplenic transplantation of the differentiated cells prevented fatal liver failure in 90%-hepatectomized rats. In conclusion, a clonal stem cell line derived from adult rat bone marrow could differentiate into hepatocyte-like cells, and transplantation of the differentiated cells could prevent fatal liver failure in 90%-hepatectomized rats. The present results indicate a promising strategy for treating human fatal liver diseases.

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We had previously demonstrated the participation of whole bone marrow cells from adult mice in the reconstitution of skin, including the epidermis and hair follicles. To get an insight into cell populations that give rise to the epithelial components of the reconstituted skin, we fractionated bone marrow cells derived from green fluorescent protein-transgenic mice by density gradient. Unexpectedly, we found that a substantial amount of mononucleated cells (approximately 30%) was recovered in the pellet fraction and that the cells in the pellet fraction preferentially differentiated into epithelial components of skin, rather than the cells in the mononuclear cell fraction. The pellet fraction contained more CD45-negative (thus uncommitted to the hematopoietic cell lineage) cells than the mononuclear cell fraction. These results indicate that density gradient fractionation results in significant loss of specific progenitor cells into the usually discarded pellet fraction.

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BACKGROUND: Patients with castration-resistant prostate cancer (CRPC) and bone metastases have an unmet clinical need for effective treatments that improve quality of life and survival with a favorable safety profile. OBJECTIVE: To prospectively evaluate the efficacy and safety of three different doses of radium chloride (Ra 223) in patients with CRPC and bone metastases. DESIGN, SETTING, AND PARTICIPANTS: In this phase 2 double-blind multicenter study, 122 patients were randomized to receive three injections of Ra 223 at 6-wk intervals, at doses of 25 kBq/kg (n=41), 50 kBq/kg (n=39), or 80 kBq/kg (n=42). The study compared the proportion of patients in each dose group who had a confirmed decrease of =50% in baseline prostate-specific antigen (PSA) levels. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Efficacy was evaluated using blood samples to measure PSA and other tumor markers, recorded skeletal-related events, and pain assessments. Safety was evaluated using adverse events (AEs), physical examination, and clinical laboratory tests. The Jonckheere-Terpstra test assessed trends between groups. RESULTS AND LIMITATIONS: The study met its primary end point with a statistically significant dose-response relationship in confirmed =50% PSA declines for no patients (0%) in the 25-kBq/kg dose group, two patients (6%) in the 50-kBq/kg dose group, and five patients (13%) in the 80-kBq/kg dose group (p=0.0297). A =50% decrease in bone alkaline phosphatase levels was identified in six patients (16%), 24 patients (67%), and 25 patients (66%) in the 25-, 50-, and 80-kBq/kg dose groups, respectively (p

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Arsenic is accumulated by free-living small mammals, but there is little information on the resultant concentrations in different tissues other than liver and kidney. Such information is important because the severity of toxicological effects may be related to the amount of arsenic accumulated in specific organs, and the availability of arsenic to predators is, in part, dependent on which tissues accumulate arsenic. The objective of this study was to quantify the arsenic concentrations and the percentage of the total body burden (%TBB) accumulated in different body tissues of free-living small mammals and to determine how these factors varied with severity of habitat contamination. Arsenic concentrations were measured in various tissues of wood mice (Apodemus sylvaticus) and bank voles (Clethrionomys glareolus) from a range of arsenic-contaminated sites in southwest Britain. Arsenic concentrations in the gastrointestinal (GI) tract (including contents), liver, kidneys, spleen, lung, femur, and fur of both species varied significantly between sites and were higher in mice and voles from heavily contaminated areas. Heart and brain arsenic concentrations did not vary with degree of environmental contamination. The GI tract and excised carcass contained roughly equal amounts of arsenic and, in sum, comprised 75-85% of the TBB on uncontaminated sites and 90-99% on contaminated sites. Although the excised carcass contains about half of the TBB, its importance in food-chain transfer of arsenic to predators may depend on the bioavailability of arsenic sequestered in fur. In contrast, the GI tract and its contents, provided that it is consumed, will always be a major transfer pathway for arsenic to predators, regardless of the severity of habitat contamination.

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Arsenic can be highly toxic to mammals but there is relatively little information on its transfer to and uptake by free-living small mammals. The aim of this study was to determine whether intake and accumulation of arsenic by wild rodents living in arsenic-contaminated habitats reflected environmental levels of contamination and varied between species, sexes and age classes. Arsenic concentrations were measured in soil, litter, wood mice (Apodemus sylvaticus) and bank voles (Clethrionomys glareolus) from six sites which varied in the extent to which they were contaminated. Arsenic residues on the most contaminated sites were three and two orders of magnitude above background in soil and litter, respectively. Arsenic concentrations in the stomach contents, liver, kidney and whole body of small mammals reflected inter-site differences in environmental contamination. Wood mice and bank voles on the same sites had similar concentrations of arsenic in their stomach contents and accumulated comparable residues in the liver, kidney and whole body. Female bank voles, but not wood mice, had significantly higher stomach content and liver arsenic concentrations than males. Arsenic concentration in the stomach contents and body tissues did not vary with age class. The bioaccumulation factor (ratio of arsenic concentration in whole body to that in the diet) in wood mice was not significantly different to that in bank voles and was 0.69 for the two species combined, indicating that arsenic was not bioconcentrated in these rodents. Overall, this study has demonstrated that adult and juvenile wood mice and bank voles are exposed to and accumulate similar amounts of arsenic on arsenic-contaminated mine sites and that the extent of accumulation depends upon the level of habitat contamination.

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ABSTRACT: Bone-seeking radionuclides including samarium-153 ethylene diamine tetramethylene phosphonate and strontium-89 have been used for decades in the palliation of pain from bone metastases especially from prostate cancer. Emerging evidence of improved survival in metastatic castration-resistant prostate cancer (CRPC) with the first-in-class a-radionuclide, radium-223 (Ra) has rekindled interest in the role of bone-seeking radionuclide therapy.We review the literature for randomized controlled trials of bone-seeking radionuclides and explore some of the issues regarding the optimal use of these agents. In particular, we discuss dose, dose rate, radiobiology, and quality of radiation and postulate on potential future directions in particular combination schedules. ß-Emitting, bone-seeking radionuclides have proven ability to control pain in prostate cancer metastatic to bone with pain response rates in the order of 60% to 70% when used as single agents. Most of the published trials were underpowered to detect differences in survival; however, there is evidence of the potential for disease modification when these agents are used in combination with chemotherapy or in multiple cycles.Data from the recent phase III ALSYMPCA trial that compared Ra to placebo in symptomatic CRPC demonstrate a significant improvement in median overall survival of 3.6 months for patients with symptomatic CRPC metastatic to bone treated with 6 cycles of the a-emitting radionuclide Ra compared with placebo. The success of Ra in improving survival in CRPC will lead this agent to become part of the treatment paradigm for this disease, and with such an excellent safety profile, Ra has huge potential in combination strategies as well as for use earlier in the natural history of metastatic prostate cancer.

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Conflicting results have been reported on the detection of paramyxovirus transcripts in Paget's disease, and a possible explanation is differences in the sensitivity of RT-PCR methods for detecting virus. In a blinded study, we found no evidence to suggest that laboratories that failed to detect viral transcripts had less sensitive RT-PCR assays, and we did not detect measles or distemper transcripts in Paget's samples using the most sensitive assays evaluated.

Introduction: There is conflicting evidence on the possible role of persistent paramyxovirus infection in Paget's disease of bone (PDB). Some workers have detected measles virus (MV) or canine distemper virus (CDV) transcripts in cells and tissues from patients with PDB, but others have failed to confirm this finding. A possible explanation might be differences in the sensitivity of RT-PCR methods for detecting virus. Here we performed a blinded comparison of the sensitivity of different RT-PCR-based techniques for MV and CDV detection in different laboratories and used the most sensitive assays to screen for evidence of viral transcripts in bone and blood samples derived from patients with PDB.

Materials and Methods: Participating laboratories analyzed samples spiked with known amounts of MV and CDV transcripts and control samples that did not contain viral nucleic acids. All analyses were performed on a blinded basis.

Results: The limit of detection for CDV was 1000 viral transcripts in three laboratories (Aberdeen, Belfast, and Liverpool) and 10,000 transcripts in another laboratory (Manchester). The limit of detection for MV was 16 transcripts in one laboratory (NIBSC), 1000 transcripts in two laboratories (Aberdeen and Belfast), and 10,000 transcripts in two laboratories (Liverpool and Manchester). An assay previously used by a U.S.-based group to detect MV transcripts in PDB had a sensitivity of 1000 transcripts. One laboratory (Manchester) detected CDV transcripts in a negative control and in two samples that had been spiked with MV. None of the other laboratories had false-positive results for MV or CDV, and no evidence of viral transcripts was found on analysis of 12 PDB samples using the most sensitive RT-PCR assays for MV and CDV.

Conclusions: We found that RT-PCR assays used by different laboratories differed in their sensitivity to detect CDV and MV transcripts but found no evidence to suggest that laboratories that previously failed to detect viral transcripts had less sensitive RT-PCR assays than those that detected viral transcripts. False-positive results were observed with one laboratory, and we failed to detect paramyxovirus transcripts in PDB samples using the most sensitive assays evaluated. Our results show that failure of some laboratories to detect viral transcripts is unlikely to be caused by problems with assay sensitivity and highlight the fact that contamination can be an issue when searching for pathogens by sensitive RT-PCR-based techniques.

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Results of recent studies have indicated that bone marrow cells can differentiate into various cells of ectodermal, mesodermal, and endodermal origins when transplanted into the body. However, the problems associated with those experiments such as the long latent period, rareness of the event, and difficulty in controlling the processes have hampered detailed mechanistic studies. In the present study, we examined the potency of mouse bone marrow cells to differentiate into cells comprising skin tissues using a skin reconstitution assay. Bone marrow cells from adult green fluorescent protein (GFP)-transgenic mice were transplanted in a mixture of embryonic mouse skin cells (17.5 days post-coitus) onto skin defects made on the backs of nude mice. Within 3 weeks, fully differentiated skin with hair was reconstituted. GFP-positive cells were found in the epidermis, hair follicles, sebaceous glands, and dermis. The localization and morphology of the cells, results of immunohistochemistry, and results of specific staining confirmed that the bone marrow cells had differentiated into epidermal keratinocytes, sebaceous gland cells, follicular epithelial cells, dendritic cells, and endothelial cells under the present conditions. These results indicate that this system is suitable for molecular and cellular mechanistic studies on differentiation of stem cells to various epidermal and dermal cells.

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Evidence suggests that increased fruit and vegetable (FV) intake may be associated with improved bone health, but there is limited evidence from intervention trials to support this. This 16-week study showed that increased FV consumption (five or more portions per day) does not have any effect on the markers of bone health in older adults. INTRODUCTION: Observational evidence suggests that increased FV consumption may be associated with improved bone health. However, there is lack of evidence from intervention trials to support this. This study examined the effect of increased FV consumption on bone markers among healthy, free-living older adults. METHODS: A randomised controlled trial was undertaken. Eighty-three participants aged 65-85 years, habitually consuming less than or equal to two portions of FV per day, were randomised to continue their normal diet or to consume five or more portions of FV per day for 16 weeks. FV were delivered to all participants each week, free of charge. Compliance was assessed at baseline and at 6, 12 and 16 weeks by diet histories and biomarkers of micronutrient status. Fasting serum bone markers (osteocalcin (OC) and C-terminal telopeptide of type 1 collagen (CTX)) were measured using enzyme-linked immunosorbent assay. RESULTS: Eighty-two participants completed the intervention. The five portions per day group showed a significantly greater change in daily FV consumption compared to the two portions per day group (p?