Results: A coefficient of variation (CV) below 10% was obtained in terms of total variance and repeatability for ADP and EPI agonists. By the ability of the device determining simultaneously platelet ...aggregation and ATP release, we hope to improve our diagnosis of platelet disorders in our laboratory.
The aim of this study is to evaluate the analytical performance of the new Sysmex XN-2000® analyzer in our routine laboratory. Overall, 798 adult and 340 pediatric blood samples were analyzed during ...a period of 3weeks on the Sysmex XN-2000® and Advia 2120i® as well as 100 body fluids. Analytical parameters as within-run and inter-day precisions, carry-over, linearity, limit of quantification, stability are excellent for the complete blood count (CBC) and correlation with Advia results shows high concordance between most parameters, except for the monocytes counts which are systematically higher with the Sysmex XN-2000®. The body fluids module shows high precision (CV<10%) for WBC with negligible carry-over and excellent linearity. However, the BF module cannot give a number of RBC below 1000μL. RBC results are only provided in interval of 103/μL cells with no intermediate counts. We concluded that the Sysmex XN-2000 provides highly reliable results. However, in our view, improvement of RBC count is mandatory and impairs full-automated counts of this kind of samples.
Le but de cette étude est l’évaluation des performances analytiques du nouveau Sysmex XN 2000® (Sysmex, Japon) au laboratoire de routine. Au total, 798 échantillons sanguins adultes et 340 pédiatriques ont été analysés en parallèle sur le Sysmex XN-2000® et sur l’Advia 2120i® (Siemens, Allemagne), ainsi que 100 liquides biologique. Notre évaluation a porté sur les précisions intra-jour et inter-jour, le degré de contamination, la linéarité et la limite de quantification avec des résultats excellents pour tous les paramètres de l’hémogramme. La comparaison avec l’appareil Advia 2120i® montre une absence de biais pour tous les paramètres analysés, à l’exception du comptage des monocytes qui est plus élevé avec le Sysmex XN-2000®. Le module d’analyse des liquides biologiques (BF) montre également une grande performance en termes de précision, de contamination et de linéarité pour les comptages des leucocytes et des érythrocytes (GR). Toutefois, ce module manque de sensibilité pour des valeurs inférieures à 1000GR/μL et il est impossible d’avoir des valeurs intermédiaires de GR, l’appareil les dénombrant uniquement par tranche de 1000GR/μL. En conclusion, le Sysmex XN-2000® fournit des résultats fiables. Cependant, à notre point de vue, l’amélioration du comptage des GR dans les liquides est une condition indispensable.
Pediatric venous thromboembolism is a multifactorial disorder with an annual incidence of 1/100.000 patients (0-18 years). The presence of central venous catheters is a major trigger for development ...of venous thrombosis, especially in neonates. As a consequence, thrombosis in the upper extremities are much more frequent in children than in adults. Congenital prothrombotic disorders may play a role in children thrombosis, often in combination with several acquired risk factors like immobilization, serious illness and/or hospitalization. Diagnosis is most frequently made by noninvasive radiologic techniques, like ultrasonography. Prophylaxis and treatment are extrapolated from adult patient protocols or small observational studies performed in small groups of patients.
Stem cell factor (SCF) is a newly described hematopoietic growth factor that stimulates the growth of primitive hematopoietic progenitors and mast cells. Since the osteoclast precursor is ...hematopoietic in origin, we tested SCF for its capacity to stimulate the formation of osteoclast-like multinucleated cells (MNC) in long-term human marrow cultures. These MNC express an osteoclast phenotype and form resorption lacunae on calcified matrices. Addition of SCF alone (0.1 pg/ml to 100 ng/ml) to long-term marrow cultures did not increase MNC formation. However, treatment of these cultures sequentially with SCF for 1 week followed by 1,25-(OH)2D3 for the second and third weeks of culture significantly enhanced MNC formation. 3HThymidine incorporation studies showed that SCF increased the proliferation of MNC precursors. These data suggested that SCF was acting on early MNC precursors. We then tested the capacity of SCF to stimulate the formation of colonies of committed precursors for osteoclast-like MNC. SCF (20 pg/ml to 20 ng/ml) enhanced osteoclast precursor formation in unfractionated bone marrow mononuclear cells but was unable to increase osteoclast precursor formation when a highly purified population of hematopoietic precursors was used as the target cells for SCF. These data suggest that SCF works in concert with other factors produced by nonhematopoietic marrow cells to increase the precursor pool for osteoclasts and that other factors, such as 1,25-(OH)2D3, complete the differentiation process to the mature osteoclast.
Several studies have suggested a role of bone marrow stroma injury in long-term chemotherapy-induced hematopoietic failure. To evaluate whether bone marrow microenvironment is altered by chemotherapy ...for acute lymphoblastic leukemia (ALL) and to determine its contribution to postchemotherapy anemia, we investigated the ability of stroma from children receiving maintenance chemotherapy for ALL to support hematopoiesis. Long-term bone marrow cultures (LTBMC) were established with bone marrow cells either from ALL children under therapy (n = 24) or from control subjects (n = 19). Nonadherent cells and colony forming units-granulocytic monocytic (CFU-GM) output in LTBMC did not differ between patients and controls. In contrast, burst forming unit-erythroid (BFU-E) numbers were lower in patient LTBMC (p = 0.013). Co-cultures of normal CD34+ cells and preformed patient or control stromas showed significantly reduced hematopoietic supportive capabilities of patient stromas: both CFU-GM and BFU-E were reduced (p = 0.002 and 0.046, respectively). In addition, supernatants (SN) of patients' LTBMC inhibited normal BFU-E growth compared with SN of normal LTBMC. Transforming growth factor (TGF)-beta1 levels were increased in patient cultures (p = 0.0039) and inversely correlated with BFU-E produced in LTBMC (r = -0.36, p = 0.04). Neutralization of TGF-beta1 significantly increased the BFU-E output of patient LTBMC (p = 0.0078). In contrast, macrophage inflammatory peptide (MIP)-1alpha levels were lower in SN of patients compared with controls (p = 0.015). Thus, chemotherapy for ALL induces functional deregulation within bone marrow stromal cells with an increase in the growth-inhibiting factor TGF-beta1, together with a decrease in MIP-1alpha, which might contribute to hematopoietic toxicity.
Osteoclast-like cell (OCL-like) differentiation is increased in long term cultures of bone marrow taken from paralyzed areas of paraplegic patients. Among the neuropeptides recently described in ...bone, calcitonin gene-related peptide (CGRP) has been shown in animal studies to inhibit bone resorption in vivo and OCL-like differentiation in vitro: its deficiency could thus be a link between the neural lesion and increased OCL-like production in paraplegia and some other neurologic disorders. We therefore investigated in this study the effects of CGRP on human OCL-like formation and found that it indeed has an inhibitory effect mediated at least in part via cAMP.
Paget’s disease—A VDR coactivator disease? Kurihara, Noriyoshi; Ishizuka, Seiichi; Demulder, Anne ...
Journal of steroid biochemistry and molecular biology,
05/2004, Volume:
89, Issue:
1-5
Journal Article, Conference Proceeding
Peer reviewed
Paget’s disease is the most exaggerated example of bone remodeling with increased osteoclastic bone resorption followed by excessive bone formation. One of the earliest findings in our studies of ...Paget’s disease is that pagetic osteoclast (OCL) precursors are hyper-responsive to 1,25-(OH)
2D
3 and form OCL at concentrations of 1,25-(OH)
2D
3 that are physiologic rather than pharmacologic. The increased responsivity to 1,25-(OH)
2D
3 is not due to increased levels of the Vitamin D receptor (VDR) or to increased infinity of 1,25-(OH)
2D
3 for VDR. We have recently shown using GST-VDR chimeric protein pull-down assays that TAF
II-17, a member of the TAF
II-D transcription complex, is increased in OCL precursors from patients with Paget’s disease compared to normals. We further showed that TAF
II-17 can enhance VDR mediated gene transcription and allow formation of the transcription complex at very low levels of 1,25-(OH)
2D
3. In addition, coactivators of VDR including CPB300 and DRIP205 are also increased in OCL precursors from Paget’s patients. These data suggest that the enhanced sensitivity of OCL precursors for 1,25-(OH)
2D
3 in Paget’s disease results from increased expression of coactivators of VDR and suggest that part of the pathophysiology underlying OCL formation in Paget’s disease may result from enhanced expression of VDR coactivators.
Cell biology of paget's disease Reddy, Sakamuri V.; Menaa, Cheikh; Singer, Frederick R. ...
Journal of bone and mineral research,
November 1999, Volume:
14, Issue:
S2
Journal Article, Conference Proceeding
Peer reviewed
Open access
Paget's disease is characterized by markedly increased osteoclast formation and bone resorption followed by excessive new bone formation. Osteoclasts in Paget's disease are increased both in number ...and size, contain paramyxoviral‐like nuclear inclusions, and can have up to 100 nuclei per cell. Marrow culture studies have identified several abnormalities in osteoclast formation in Paget's disease. Osteoclast‐like multinucleated cells formed more rapidly in marrow cultures from patients with Paget's disease, produced increased levels of inter‐leukin‐6 (IL‐6), and expressed high levels of IL‐6 receptors compared to normals. IL‐6 levels were also increased in bone marrow and peripheral blood of patients with Paget's disease. In addition, osteoclast precursors from patients with Paget's disease are hyperresponsive to 1,25‐dihydroxyvitamin D3 (1,25(OH)2D3) and calcitonin. The increased sensitivity of osteoclast precursors to 1,25(OH)2D3 is mediated through the vitamin D receptor (VDR), since 24‐hydroxylase activity is also up‐regulated at concentrations of 1,25(OH)2D3 that are one log less than that needed to induce 24‐hydroxylase activity in osteoclast precursors from normals. However, VDR numbers and affinity for 1,25(OH)2D3 do not differ in osteoclast precursors from Paget's patients compared to those from normals. Synergistic interactions between cytokines such as IL‐6 and 1,25(OH)2D3 also cannot explain the enhanced sensitivity of osteoclast precursors from patients with Paget's disease to 1,25(OH)2D3. Interestingly, coculture studies of osteoclast precursors and cells from the marrow microenvironment of patients with Paget's disease and normals have demonstrated that the marrow microenvironment is more osteoclastogenic than normal. Thus, studies of the cell biology of osteoclasts in Paget's disease have demonstrated an increased rate of osteoclast formation and abnormalities in both osteoclast precursors and the marrow microenvironment Enhanced IL‐6 production by osteoclasts in Paget's disease may further amplify the increased osteoclast formation already ongoing in the pagetic lesion, and may explain the increased bone turnover at uninvolved sites distant from the pagetic lesion.
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