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1.
D. M. Reid I. Mackay S. Wilkinson C. Miller D. G. Schuette J. Compston C. Cooper E. Duncan N. Galwey R. Keen B. Langdahl A. McLellan H. Pols A. Uitterlinden J. O’Riordan J. A. H. Wass S. H. Ralston S. T. Bennett 《Osteoporosis international》2006,17(1):125-132
Osteoporosis is a common disease with a strong genetic component characterized by reduced bone mass and an increased risk of fragility fractures. Bone mineral density (BMD) is the most important determinant of osteoporotic fracture risk, but the genes responsible for BMD regulation and fracture are incompletely defined. To enable multi-center studies to examine the genetic influences on BMD there is a requirement to standardize measurements across different manufacturers of bone densitometers, different versions of machines and different normative ranges. This paper describes a method developed to allow near-identical subjects with low age-adjusted BMD (based on Z-scores) to be recruited in 17 centers using 27 different densitometers. Cross-calibration was based on measurements using a European spine phantom circulated to all centers and measured ten times on each individual machine. From theses values an individual exponential curve, based on nominal versus observed BMD, was derived for each machine. As expected, there were large and significant variations in nominal BMD values, not only between scanners from different manufacturers but also between different versions of scanners from the same manufacturer. Hologic scanners tended to underestimate the nominal BMD, while Lunar scanners overestimated the value. Norland scanners gave mixed values over estimating BMD at the lower nominal value (0.5 g/cm2) while underestimating the value at the higher value (1.5 g/cm2). The validity of the exponential equations was tested using hip and spine measurements on 991 non-proband women from a familial osteoporosis study (FAMOS). After cross-calibration there was a considerable reduction in variation between machines. This observation, coupled with the absence of a similar reduction in variation attributable to a linear regression on age, demonstrated the validity of the cross-calibration approach. Use of the cross-calibration curves along with a standard normative range (in the case of this study, the Hologic normative range) allowed age-specific Z-scores to be used as an inclusion criterion in this genetic study, a method that will be useful for other trials where age-specific BMD inclusion criteria are required. 相似文献
2.
D J Doudet C A McLellan R Carson H R Adams H Miyake T G Aigner R T Finn R M Cohen 《Journal of cerebral blood flow and metabolism》1991,11(5):726-734
Most attempts to model accurately [18F]-DOPA imaging of the dopamine system are based on the assumptions that its main peripheral metabolite, 3-O-methyl-6-[18F]fluoro-L-DOPA ([18F]3-OM-DOPA), crosses the blood-brain barrier but is present as a homogenous distribution throughout the brain, in part because it is not converted into [18F]DOPA in significant quantities. These assumptions were based mainly on data in rodents. Little information is available in the primate. To verify the accuracy of the above assumptions, we administered 18F-labeled 3-OM-DOPA to normal rhesus monkeys and animals with lesions of the DA nigrostriatal system. No selective 18F regional accumulation in brain was apparent in normal or lesioned animals. The plasma metabolite analysis revealed that only the negatively charged metabolites (e.g., sulfated conjugates) that do not cross the blood-brain barrier were found in significant quantities in the plasma. A one-compartment, three-parameter model was adequate to describe the kinetics of [18F]3-OM-DOPA. In conclusion, assumptions concerning [18F]3-OM-DOPA's behavior in brain appear acceptable for [18F]DOPA modeling purposes. 相似文献
3.
To determine the accuracy of bibliographic citation in the anesthesia literature, we reviewed all 1988 volumes of ANESTHESIOLOGY, Anesthesia and Analgesia, British Journal of Anaesthesia, and Canadian Journal of Anaesthesia and sequentially numbered all references appearing in that year (n = 22,748). One hundred references from each of the four journals were randomly selected. After citations to nonjournal articles (i.e., books or book chapters) were excluded, the remaining 348 citations were analyzed in detail. Six standard bibliographic elements--authors' names, article title, journal title, volume number, page numbers, and year--were examined in each selected reference. Primary sources were reviewed, unless our institution did not own the source or could not obtain it through interlibrary loan, in which case standard indexes, abstracting services, and computerized databases were consulted. Each element was checked for accuracy, and references were classified as either correct or incorrect. A reference was correct if each element of the citation was identical to its source. Of the examined references, more than half (50.3%) contained an error in at least one element. The elements most likely to be inaccurate were, in descending order, article title, author, page numbers, journal title, volume number, and year. No significant differences (P = 0.283) existed in the error rates of the four journals; the percentage of citations containing at least one error ranged from 44% (Anesthesia and Analgesia) to 56% (British Journal of Anaesthesia). The citation error rate of anesthesia journals is similar to that reported in other specialties, where error rates ranging from 38% to 54% have been documented. 相似文献
4.
5.
A reassessment of the role of arteriography in penetrating proximity extremity trauma: a prospective study 总被引:4,自引:0,他引:4
E R Frykberg J M Crump F S Vines G L McLellan J W Dennis R G Brunner R H Alexander 《The Journal of trauma》1989,29(8):1041-50; discussion 1050-2
Penetrating proximity extremity trauma (PPET) was prospectively studied to clarify the role of routine arteriographic evaluation (AG). Over a 24-month period, 135 patients were identified with 152 injuries from PPET. All patients underwent AG and were randomized to either immediate or delayed timing. There were 27 arteriographic abnormalities from these 152 wounds, of which 16 (10.5%) were in major arteries. One acute arteriovenous fistula underwent immediate surgery. The remaining 15 major vessel injuries were nonoperatively observed, including seven cases of segmental arterial narrowing, six intimal flaps, and two small pseudoaneurysms (one of which enlarged and underwent surgical repair after 10 weeks of followup). Nine of the remaining 14 lesions resolved; two improved and three remained clinically unchanged over a mean followup interval of 2.7 months. Shotgun trauma was the mechanism which carried the greatest risk of significant vascular injury. Although "soft" clinical signs were significantly more predictive of vascular injury following PPET than proximity alone (p less than 0.0005), 50% of all injuries to major arteries did not manifest soft signs. No extremity morbidity resulted from delayed AG or from vascular injury management. We conclude from our study population: 1) the natural history of clinically occult arterial injuries was predominantly benign; 2) AG could be safely delayed up to 24 hours; 3) "soft" signs were not clinically useful predictors of vascular injury; and 4) with the exception of shotgun wounds, AG did not appear to be a cost effective screening modality, since detection of a single vascular injury requiring surgery cost $66,420.00. 相似文献
6.
An absolute lymphocyte count is included in the routine results provided by most automated blood cell counters, providing a prompt indication of peripheral blood lymphocytosis. Transient lymphocytosis is seen in many acutely ill patients, including those with multiple injuries. We have observed a significantly higher death rate among trauma patients with lymphocytosis at presentation; patients with lymphocytosis, on subsequent assessment of injury, proved to have higher Injury Severity Scores than those without lymphocytosis. Investigation of lymphocyte subsets in nine patients with lymphocytosis showed an increase in T cells, reversal of the CD4:CD8 ratio, and, in seven patients, an increase in "natural killer" cells. The presence of lymphocytosis and its early detection as part of a routine blood count may supply a readily available means of identifying a high-risk trauma patient. 相似文献
7.
8.
Antibodies against listerial protein 60 act as an opsonin for phagocytosis of Listeria monocytogenes by human dendritic cells 下载免费PDF全文
Kolb-Mäurer A Pilgrim S Kämpgen E McLellan AD Bröcker EB Goebel W Gentschev I 《Infection and immunity》2001,69(5):3100-3109
Human-monocyte-derived dendritic cells (MoDC) are very efficient in the uptake of Listeria monocytogenes, a gram-positive bacterium which is an important pathogen in humans and animals causing systemic infections with symptoms such as septicemia and meningitis. In this work, we analyzed the influence of blood plasma on the internalization of L. monocytogenes into human MoDC and compared the uptake of L. monocytogenes with that of Salmonella enterica serovar Typhimurium and Yersinia enterocolitica. While human plasma did not significantly influence the uptake of serovar Typhimurium and Y. enterocolitica by human MoDC, the efficiency of the uptake of L. monocytogenes by these phagocytes was strongly enhanced by human plasma. In plasma-free medium the internalization of L. monocytogenes was very low, whereas the addition of pooled human immunoglobulins resulted in the internalization of these bacteria to a degree comparable to the highly efficient uptake observed with human plasma. All human plasma tested contained antibodies against the 60-kDa extracellular protein of L. monocytogenes (p60), and anti-p60 antibodies were also found in the commercially available pooled immunoglobulins. Strikingly, in contrast to L. monocytogenes wild type, an iap deletion mutant (totally deficient in p60) showed only a minor difference in the uptake by human MoDC in the presence or the absence of human plasma. These results support the assumption that antibodies against the listerial p60 protein may play an important role in Fc-receptor-mediated uptake of L. monocytogenes by human MoDC via opsonization of the bacteria. This process may have a major impact in preventing systemic infection in L. monocytogenes in immunocompetent humans. 相似文献
9.
Identification of a novel dendritic cell surface antigen defined by carbohydrate specific CD24 antibody cross-reactivity. 总被引:1,自引:0,他引:1 下载免费PDF全文
Dendritic cells (DC) are characterized as leucocytes that lack mature lineage specific markers and stimulate naive T-lymphocyte proliferation in vitro and in vivo. The mouse heat stable antigen (HSA) participates in T lymphocyte co-stimulation and is expressed by DC isolated from thymus, skin and spleen. The human HSA homologue, CD24, is predominantly expressed by B lymphocytes and granulocytes, but its expression on DC has not been studied in detail. CD24 clearly participates in B-lymphocyte signalling but co-stimulatory activity for T lymphocytes has not yet been described. We have examined the expression of CD24 on human peripheral blood DC populations isolated directly or following in vitro culture. The CD24 antigen was absent from blood DC however, cross-reactive sialylated carbohydrate epitopes were detected on DC with some CD24 monoclonal antibodies (mAb). These CD24 mAb define a protein surface antigen, which is expressed by an immature or resting subpopulation of peripheral blood DC and is down-regulated following activation differentiation in vitro. 相似文献
10.
Expression of multilectin receptors and comparative FITC-dextran uptake by human dendritic cells 总被引:7,自引:0,他引:7
Kato M Neil TK Fearnley DB McLellan AD Vuckovic S Hart DN 《International immunology》2000,12(11):1511-1519