965 resultados para NORTH-AMERICAN SOCIETY
Resumo:
Chronic obstructive pulmonary disease (COPD) is associated with osteoporosis and fragility fractures. The objectives of this study were to assess static and dynamic indices of cancellous and cortical bone structure in postmenopausal women with COPD. Twenty women with COPD who had not received chronic oral glucocorticoids underwent bone biopsies after double tetracycline labeling. Biopsies were analyzed by histomorphometry and mu CT and compared with age-matched controls. Distribution of the patients according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) was: Type I (15%), Type II (40%), Type III (30%), and Type IV (15%). Mean (+/-SD) cancellous bone volume (15.20 +/- 5.91 versus 21.34 +/- 5.53%, p = .01), trabecular number (1.31 +/- 0.26 versus 1.77 +/- 0.51/mm, p = .003), and trabecular thickness (141 +/- 23 versus 174 +/- 36 mu m, p = .006) were lower in patients than in controls. Connectivity density was lower in COPD (5.56 +/- 2.78 versus 7.94 +/- 3.08 mu m, p = .04), and correlated negatively with smoking (r = -0.67; p = .0005). Trabecular separation (785 +/- 183 versus 614 +/- 136 mu m, p = .01) and cortical porosity (4.11 +/- 1.02 versus 2.32 +/- 0.94 voids/mm(2); p < .0001) were higher in COPD while cortical width (458 +/- 214 versus 762 +/- 240 mu m; p < .0001) was lower. Dynamic parameters showed significantly lower mineral apposition rate in COPD (0.56 +/- 0.16 versus 0.66 +/- 0.12 mu m/day; p = .01). Patients with more severe disease, GOLD III and IV, presented lower bone formation rate than GOLDI and II (0.028 +/- 0.009 versus 0.016 +/- 0.011 mu m(3)/mu m(2)/day;p = 04). This is the first evaluation of bone microstructure and remodeling in COPD. The skeletal abnormalities seen in cancellous and cortical bone provide an explanation for the high prevalence of vertebral fractures in this disease. (C) 2010 American Society for Bone and Mineral Research.
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This report describes the identification of a murine cytomegalovirus (MCMV) G protein-coupled receptor (GCR) homolog. This open reading frame (M33) is most closely related to, and collinear with, human cytomegalovirus UL33, and homologs are also present in human herpesvirus 6 and 7 (U12 for both viruses). Conserved counterparts in the sequenced alpha- or gammaherpesviruses have not been identified to date, suggesting that these genes encode proteins which are important for the biological characteristics of betaherpesviruses. We have detected transcripts for both UL33 and M33 as early as 3 or 4 h postinfection, and these reappear at late times. In addition, we have identified N-terminal splicing for both the UL33 and M33 RNA transcripts. For both open reading frames, splicing results in the introduction of amino acids which are highly conserved among known GCRs. To characterise the function of the M33 in the natural host, two independent MCMV recombinant viruses were prepared, each of which possesses an M33 open reading frame which has been disrupted with the beta-galactosidase gene. While the recombinant M33 null viruses showed no phenotypic differences in replication from wild-type MCMV in primary mouse embryo fibroblasts in vitro, they showed severely restricted growth in the salivary glands of infected mice. These data suggest that M33 plays an important role in vivo, in particular in the dissemination to or replication in the salivary gland, and provide the first evidence for the function of a viral GCR homolog in vivo.
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Papillomaviruses (PVs) bind in a specific and saturable fashion to a range of epithelial and other cell lines. Treatment of cells with trypsin markedly reduces their ability to bind virus particles, suggesting that binding is mediated via a cell membrane protein. We have investigated the interaction bf human PV type 6b L1 virus-like particles (VLPs) with two epithelial cell lines, CV-1 and HaCaT, which bind VLPs, and a B-cell line (DG75) previously shown not to bind VLPs. Immunoprecipitation of a mixture of PV VLPs with [S-35]methionine-labeled cell extracts and with biotin-labeled cell surface proteins identified four proteins from CV-1 and HaCaT cells of 220, 120, 87, and 35 kDa that reacted with VLPs and were not present in DG75 cells. The alpha(6) beta(4) integrin complex has subunits corresponding to the VLP precipitated proteins, and the tissue distribution of this complex suggested that it was a candidate human PV receptor. Monoclonal antibodies (MAbs) to the alpha(6) or beta(4) integrin subunits precipitated VLPs from a mixture of CV-1 cell proteins and VLPs, whereas MAbs to other integrin subunits did not. An alpha(6) integrin-specific MAb (GoH3) inhibited VLP binding to CV-1 and HaCaT cells, whereas an anti-beta(4) integrin MAb and a range of integrin-specific and other MAbs did not. Furthermore, human laminin, the natural ligand for the alpha(6) beta(4) integrin, was able to block VLP binding. By use of sections of monkey esophagus, the distribution of alpha(6), integrin expression in the basal epithelium was shown to coincide with the distribution of bound VLPs. Taken together, these data suggest that VLPs bind specifically to the alpha(6) integrin subunit and that integrin complexes containing alpha(6) integrin complexed with either beta(1) or beta(4) integrins may act as a receptor for PV binding and entry into epithelial cells.
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An aggregate-forming coccus, isolated twice as the predominant microorganism in sputa from a cystic fibrosis patient on consecutive days, was shown to belong to the species Lautropia mirabilis on the bases of similarities of 16S rRNA gene sequences and phenotype. These isolates of L. mirabilis appear to be the first reported from a patient with cystic fibrosis and outside of Denmark.
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Background and objectives Fibroblast growth factor 23 (FGF-23) has emerged as a new factor in mineral metabolism in chronic kidney disease (CKD). An important regulator of phosphorus homeostasis, FGF-23 has been shown to independently predict CKD progression in nondiabetic renal disease. We analyzed the relation between FGF-23 and renal outcome in diabetic nephropathy (DN). Design, setting, participants, & measurements DN patients participating in a clinical trial (enalapril+placebo versus enalapril+losartan) had baseline data collected and were followed until June 2009 or until the primary outcome was reached. Four patients were lost to follow-up. The composite primary outcome was defined as death, doubling of serum creatinine, and/or dialysis need. Results At baseline, serum FGF-23 showed a significant association with serum creatinine, intact parathyroid hormone, proteirturia, urinary fractional excretion of phosphate, male sex, and race. Interestingly, FGF-23 was not related to calcium, phosphorus, 25OH-vitamin D, or 24-hour urinary phosphorus. Mean follow-up time was 30.7 +/- 10 months. Cox regression showed that FGF-23 was an independent predictor of the primary outcome, even after adjustment for creatinine clearance and intact parathyroid hormone (10 pg/ml FGF-23 increase = hazard ratio, 1.09; 95% CI, 1.01 to 1.16, P = 0.02). Finally, Kaplan-Meier analysis showed a significantly higher risk of the primary outcome in patients with FGF-23 values of >70 pg/ml. Conclusions FGF-23 is a significant independent predictor of renal outcome in patients with macroalbuminuric DN. Further studies should clarify whether this relation is causal and whether FGF-23 should be a new therapeutic target for CKD prevention. Clin J Am Soc Nephrol 6: 241-247, 2011. doi: 10.2215/CJN.04250510
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Background: Significant hemodynamic changes, including preload and afterload modifications, occur during the transition from the fetal to the neonatal environment. The ductus arteriosus closes, pulmonary vascular resistance decreases, and pulmonary blood flow increases. Strain rate (SR) and strain (e) have been proposed as ultrasound indices for quantifying regional wall deformation. This study was designed to determine if these indices can detect variations in regional deformation between early and late neonatal periods. Methods: Data were obtained from 30 healthy neonates (15 male). The initial study was performed at a mean age of 20.1614 hours (exam 1) and the second at 31.962.9 days (exam 2). Apical and parasternal views were used to quantify regional left ventricular (LV) and right ventricular (RV) longitudinal and radial SR and e, and systolic, early, and late diastolic values were calculated from these curves. A paired-samples t test was performed comparing the two groups. Results: Compared with exam 1, LV radial deformation showed significant reductions in peak systolic e in the basal and mid segments (51615% vs 4669%, P < .01). LV longitudinal deformation behaved similarly, showing significant peak systolic e reductions in all measured segments. Systolic SR showed reductions only in the basal and apical segments of the lateral wall and in the mid portion of the inferior wall (-1.9 +/- 0.5 vs -1.7 +/- 0.3 s(-1) and -1.9 +/- 0.4 vs -1.7 +/- 0.2 s(-1), respectively, P = .03). RV longitudinal free and inferior wall systolic SR and e values were significantly higher in exam 2. Conclusions: LV peak systolic e decreases in exam 2 were possibly due to afterload increase and preload decrease. The lower RV initial deformation indices could be attributed to increased afterload caused by physiologic pulmonary hypertension or immature RV contractile properties. SR seemed to be a more robust index than e and less influenced by preload and afterload hemodynamic alteration. (J Am Soc Echocardiogr 2010;23:294-300.)
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Background: Color Doppler myocardial imaging (CDMI) allows the calculation of local longitudinal or radial strain rate (SR) and strain (epsilon). The aims of this study were to determine the feasibility and reproducibility of longitudinal and radial SR and epsilon in neonates during the first hours of life and to establish reference values. Methods: Data were obtained from 55 healthy neonates (29 male; mean age, 20 +/- 14 hours; mean birth weight, 3,174 +/- 374 g). Apical and parasternal views quantified regional longitudinal and radial SR and epsilon in differing ventricular wall segments. Values at peak systole, early diastole, and late diastole were calculated from the extracted curves. CDMI data acquired at 300 +/- 50 frames/s were analyzed offline. Three consecutive cardiac cycles were measured during normal respiration. The timing of specific systolic or diastolic regional events was determined. Multiple comparisons between walls and segments were made. Results: Left ventricular (LV) longitudinal deformation showed basal differences compared with apical segments within one specific wall. Right ventricular (RV) longitudinal deformation was not homogeneous, with significant differences between basal and apical segments. Longitudinal 3 values were higher in the RV free basal and middle wall segments compared with the left ventricle. In the RV free wall apical segment, longitudinal SR and 3 were maximal. LV systolic SR and epsilon values were higher radially compared with longitudinally (radial peak systolic SR midportion, 2.9 +/- 0.6 s(-1); radial peak systolic epsilon 53.8 +/- 19%; longitudinal peak systolic SR midportion, -1.8 +/- 0.5 s(-1); longitudinal peak systolic epsilon, -24.8 +/- 3%; P < .01). Longitudinal systolic epsilon and SR interobserver variability values were 1.2% and 0.7%, respectively. Conclusion: Ultrasound-based SR and 3 imaging is a practical and reproducible clinical technique in neonates, allowing the calculation of regional longitudinal and radial deformation in RV and LV segments. These regional SR and epsilon indices represent new, noninvasive parameters that can quantify normal neonate regional cardiac function. Independent from visual interpretation, they can be used as reference values for diagnosis in ill neonates. (J Am Soc Echocardiogr 2009;22:369-375.)
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To date, several activating mutations have been discovered in the common signal-transducing subunit (h beta c) of the receptors for human granulocyte-macrophage colony-stimulating factor, interleukin-3, and interleukin-5. Two of these, Fl Delta and 1374N, result in a 37 amino acid duplication and a single amino acid substitution in the extracellular domain of h beta c, respectively. A third, V449E, results in a single amino acid substitution in the transmembrane domain, Previous studies comparing the activity of these mutants in different hematopoietic cell lines imply that the transmembrane and extracellular mutations act by different mechanisms and suggest the requirement for cell type-specific molecules in signalling. To characterize the ability of these mutant hpc subunits to mediate growth and differentiation of primary cells and hence investigate their oncogenic potential, we have expressed all three mutants in primary murine hematopoietic cells using retroviral transduction. It is shown that, whereas expression of either extracellular hpc mutant confers factor-independent proliferation and differentiation on cells of the neutrophil and monocyte lineages only, expression of the transmembrane mutant does so on these lineages as well as the eosinophil, basophil, megakaryocyte, and erythroid lineages, Factor-independent myeloid precursors expressing the transmembrane mutant display extended proliferation in liquid culture and in some cases yielded immortalized cell lines. (C) 1997 by The American Society of Hematology.
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We measured bone mineral content (BMC) and estimated calcium accretion in children to provide insight into dietary calcium requirements during growth. Anthropometric measurements were done semiannually and whole-body BMC was measured annually by dual-energy X-ray absorptiometry for 4 y in 228 children (471 scans in 113 boys and 507 scans in 115,girls). Mean values for BMC, skeletal area, and height were calculated for 1-y age groups from 9.5 to 19.5 y of age. Cross-sectional analysis of the pooled data gave peak height velocity and peak BMC velocity (PBMCV) and the ages at which these occurred (13.3 y in boys and 11.4 y in girls). PBMCV did not peak until 1.2 y after peak height velocity in boys and 1.6 y after peak height velocity in girls. Within 3 y on either side of PBMCV, boys had consistently higher BMC and BMC velocity compared with girls and the discrepancy increased steadily through puberty. Three years before PBMCV, BMC Values in girls were 69% of those in boys; 3 y after peak height velocity this proportion fell to 51%. PBMCV was 320 g/y in boys and 240 g/y in girls. Under the assumption that bone mineral is 32.2% calcium, these values corresponded to a daily calcium retention of 282 mg in boys and 212 mg in girls. Individual Values could be much greater. In one boy in a group of six subjects for whom there were enough data for individual analysis through puberty, PBMCV was 555 g Ca/y or 490 mg Ca/d. Such high skeletal demands for calcium require large dietary calcium intakes and such requirements may not be met immediately in some children.
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The aims of this study were to characterize the recently cloned rat norepinephrine transporter (NET) in more detail and in particular to study possible species differences in its pharmacological properties compared with the human and bovine NETs. The study was carried out by measuring the uptake of [3H]norepinephrine in COS-7 cells expressing the NET after transient transfection with rat, human, or bovine NET cDNA. There were small but significant differences between the rat NET and the human or bovine NETs with respect to the affinities of sodium ions (greater for rat than for bovine) of the substrates norepinephrine, epinephrine, and 1-methyl-4-phenylpyridinium (greater for human than for rat), and of the inhibitor cocaine (greater for human and bovine than for rat), whereas the affinities of dopamine and of most inhibitors, including tricyclic antidepressants, showed no species differences. The fact that the affinities for some substrates, cocaine and sodium ions exhibited small but significant interspecies differences among the rat, human, and bovine NETs suggests that ligand recognition, the translocation process, and sodium ion dependence are influenced differentially by just a few amino acid exchanges in the primary sequences of the transporters. On the other hand, the lack of any major differences in the pharmacological properties of the rat, human, and bovine NETs in this study suggests that data obtained in previous studies on rat tissues and bovine cells can be extrapolated, in all except the most quantitative analyses, to the properties of the human NET.
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Background & aims: Multiple definitions for malnutrition syndromes are found in the literature resulting in confusion. Recent evidence suggests that varying degrees of acute or chronic inflammation are key contributing factors in the pathophysiology of malnutrition that is associated with disease or injury. Methods: An International Guideline Committee was constituted to develop a consensus approach to defining malnutrition syndromes for adults in the clinical setting. Consensus was achieved through a series of meetings held at the ASPEN and ESPEN Congresses. Results: It was agreed that an etiology-based approach that incorporates a current understanding of inflammatory response would be most appropriate. The Committee proposes the following nomenclature for nutrition diagnosis in adults in the clinical practice setting. ""Starvation-related malnutrition"", when there is chronic starvation without inflammation, ""chronic disease-related malnutrition"", when inflammation is chronic and of mild to moderate degree, and ""acute disease or injury-related malnutrition"", when inflammation is acute and of severe degree. Conclusions: This commentary is intended to present a simple etiology-based construct for the diagnosis of adult malnutrition in the clinical setting. Development of associated laboratory, functional, food intake, and body weight criteria and their application to routine clinical practice will require validation. (C) 2009 European Society for Clinical Nutrition and Metabolism and ASPEN American Society for Parenteral and Enteral Nutrition. Published by Elsevier Ltd. All rights reserved.
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CD40 ligand (CD40-L), a member of the tumor necrosis family of transmembrane glycoproteins, is rapidly and transiently expressed on the surface of recently activated CD4+ T cells. Interactions between CD40-L and CD40 induce B cell immunoglobulin production as well as monocyte activation and dendritic cell differentiation. Since these features characterize rheumatoid arthritis (RA), the expression and function of CD40-L in RA was examined. Freshly isolated RA peripheral blood (PB) and synovial fluid (SF)T cells expressed CD40-L mRNA as well as low level cell surface CD40-L. An additional subset of CD4+ RA SF T cells upregulated cell surface CD40-L expression within 15 min of in vitro activation even in the presence of cycloheximide, but soluble CD40-L was not found in SF. CD40-L expressed by RA T cells was functional, since RA PB and SF T cells but not normal PB T cells stimulated CD40-L-dependent B cell immunoglobulin production and dendritic cell IL-12 expression in the absence of prolonged in vitro T cell activation. In view of the diverse proinflammatory effects of CD40-L, this molecule is likely to play a central role in the perpetuation of rheumatoid synovitis. Of importance, blockade of CD40-L may prove highly effective as a disease modifying therapy for RA.
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Background: The 6-minute walk test (6MWT) is a well-known instrument for assessing the functional capacity of a variety of groups, including the obese. It is a simple, low-cost and easily applied method to objectively assess the level of exercise capacity. The aim of the present study was to study the functional capacity of a severely obese population before and after bariatric surgery. Methods: A total of 51 patients were studied. Of the 51 patients, 86.2% were women, and the mean age was 40.9 +/- 9.2 years. All 51 patients were evaluated preoperatively and 49 were evaluated 7-12 months postoperatively. The initial body mass index was 51.1 +/- 9.2 kg/m(2), and the final body mass index was 28.2 +/- 8.1 kg/m(2). All patients underwent Roux-en-Y gastric bypass. The 6MWT was performed in a hospital corridor, with patients attempting to cover as much distance as they could, walking back and forth for as long as possible within 6 minutes at their regular pace. The total distance, Borg Scale of perceived exhaustion, modified Borg dyspnea scale for shortness of breath, and physical complaints at the end of the test were recorded. In addition, the heart rate and respiratory frequency were assessed before and after the test. Results: The tolerance was good, and no injuries occurred at either evaluation. The patients` mean distance for the 6MWT was 381.9 +/- 49.3 m before surgery and 467.8 +/- 40.3 m after surgery (p < .0001). Similar results were observed for the other parameters assessed. Conclusion: The 6MWT provided useful information about the functional status of the obese patients undergoing bariatric surgery. A simple, safe, and powerful method to assess functional capacity of severely obese patients, the 6MWT is an objective test that might replace the conventional treadmill test for these types of patients. (Surg Obes Relat Dis 2009;5:540-543.) (C) 2009 American Society for Metabolic and Bariatric Surgery. All rights reserved.
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The cDNAs encoding wild type (WT) human receptor tyrosine kinase c-Kit and a constitutively activated mutant, V816Kit, were introduced into granulocyte-macrophage colony-stimulating factor (GM-CSF)-dependent early murine hemopoietic cells, which had been transformed with activated Myb, WTKit cells were able to grow in the presence of the human ligand for Kit, stem cell factor (SCF), but displayed reduced growth and clonogenic potential in either SCF or GM-CSF compared with the parental cells in GM-CSF. In contrast, V816Kit cells grew without factor at a higher rate than the parental cells in GM-CSF and displayed increased clonogenicity. Dissection of the growth characteristics in liquid culture showed that in the presence of appropriate factors, the different populations had similar proliferation rates, but that V816Kit profoundly increased cell survival compared with WTKit or parental cells, This suggests that the signals transduced by WTKit activated with SCF, and by V816Kit, were not identical. Also, WTKit and V816Kit-expressing cells both varied from the early myeloid progenitor phenotype of the parental cells and gave rise to a small number of large to giant adherent cells that expressed macrophage (alpha-naphthyl acetate) esterase and neutrophil (naphtol-AS-D-chloroacetate) esterase, were highly phagocytic and phenotypically resembled histiocytes. Thus, WTKit activated by SCF and V816Kit were able to induce differentiation in a proportion of Myb-transformed myeloid cells. The factor independent V816Kit cells, unlike the parental and WTKit expressing cells, were shown to produce tumors of highly mitotic, invasive cells at various stages of differentiation in syngeneic mice. These results imply that constitutively activated Kit can promote the development of differentiated myeloid tumors and that its oncogenic effects are not restricted to lineages (mast cell and B-cell acute lymphoblastic leukemia), which have been reported previously. Furthermore, the mixed populations of cells in culture and in the tumors phenotypically resembled the leukemic cells from patients with monocytic leukemia with histiocytic differentiation (acute myeloid leukemia-M5c), a newly proposed subtype of myeloid leukemia. (C) 1997 by The American Society of Hematology.