Thrombospondin in essential thrombocythemia

Essential thrombocythemia is a myeloproliferative disorder characterized by frequent bleeding and thrombotic complications. On a molecular level, two abnormalities of platelet thrombospondin have been identified: abnormal glycosylation of the intact 185,000-dalton chain has been detected and a shortened form of the thrombospondin chain is present. We have used two monoclonal antibodies and Lens culinaris lectin to probe the structure of thrombospondin in the platelets from three patients with essential thrombocythemia; one patient with polycythemia vera and two patients with secondary thrombocytosis. The presence of abnormal thrombospondin fragments with molecular weights of 160,000 and 30,000 was detected in the intact platelets and in the supernatant from thrombin-treated platelets, in all of the individuals except one of the secondary thrombocytosis patients. Monoclonal antibody binding studies indicate that both fragments are produced by proteolysis at a single site, which results in the removal of a 30,000- dalton fragment from the NH2-terminal. Lens culinaris lectin-binding studies revealed that some of the carbohydrate moieties of thrombospondin are near this cleavage site. The results are consistent with the hypothesis that the abnormal thrombospondin fragments observed under conditions of increased platelet production are due to increased susceptibility to proteolysis which, in turn, may be due to defective glycosylation.     

Flow cytometric detection of receptors for interleukin-6 on bone marrow and peripheral blood cells of humans and rhesus monkeys

The expression of receptors for interleukin-6 (IL-6) on human and rhesus monkey peripheral blood and bone marrow (BM) cells was examined by multiparameter flow cytometry after staining with biologically active, biotin-labeled human IL-6 and phycoerythrin-conjugated streptavidin. Consistent with the multiple biologic effects of IL-6 in stimulating immune functions and hematopoiesis, IL-6 receptors were detectable on a wide variety of cell types. In peripheral blood, IL-6 receptors were detectable on monocytes, granulocytes, and on CD4+ T lymphocytes but not on resting, CD19+ B lymphocytes and CD56+ natural killer (NK) cells. CD8+ T lymphocytes also expressed IL-6 receptors but at lower levels than CD4+ cells. The IL-6 receptors on granulocytes were only detectable after staining with high concentrations of biotin- IL-6, suggesting that most IL-6 receptors on these cells represent low- affinity sites. In contrast, IL-6 receptors on both CD4+ and CD8+ T lymphocytes were detectable at biotin-IL-6 concentrations as low as 10 pmol/L, indicating that these cells bind IL-6 with high affinity. IL-6 receptor expression patterns on rhesus monkey and human blood cells were very similar except that receptor levels on granulocytes were lower in humans than in rhesus monkeys. Similar differences in expression levels were observed for IL-6 receptors that were detectable on most granulocyte precursors in the mononuclear fraction of rhesus monkey and human bone marrow. In addition to these relatively mature cell types, IL-6 receptors were detectable on a large fraction of human and rhesus monkey BM blast cells that express the CD34 antigen. The presence of IL-6 receptors on CD34+ BM blast cells, which are the precursor cells of most, if not all, BM-derived blood cells, is consistent with the ability of IL-6, in conjunction with other cytokines, to stimulate immature hemopoietic cells in vitro and to promote blood cell production when administered in vivo.     

FREDDY激光器的碎石效率的体外分析

背景和目的　双频双脉冲Nd :Yag(FREDDY)激光 (德国W .O .M .公司生产 )是一个短脉冲 ,双频率 ( 5 3 2nm和 10 64nm)的固体激光器。该激光器功率小 ,成本低 ,目前已在腔内碎石术中得到应用。我们设计了一个试验 ,以测试在不同能量和不同频率下的碎石效率。材料和方法　 40个预先称过重量的硫酸钙石头被分成 4组 ,在 5Hz和 10Hz情况下 ,分别碎石 2min和 4min。一个水下的试验装置包括一个支架和一个容器 ,使得石英玻璃光纤可以直接抵住石头 ,发射激光。光纤被剥离成直径为 2 80 μm的裸露光纤 ,以保证最佳的能量传输。碎石完成后 ,所有的残余颗粒都落在容器内 ,晾干 48小时后 ,再重新称重 ,根据重量缺失的百分比来测试碎石效果。结果　 5Hz时 ,碎石 2min的重量缺失为 2 4%;碎石 4min的重量缺失为 5 4%。 10Hz时 ,碎石 2min的情况与 5Hz时碎石 4min的结果相似 ,重量缺失为 5 1%;碎石 4min的重量缺失为 64 %,原先估计这么高的能量设置 ,重量缺失应该更大些。在高能量发射时 ,可以观察到光纤有损耗 ,这可能是导致碎石效率下降的原因。结论　FREDDY激光器在 5Hz时碎石 4min ,和在 10Hz时碎石 2min的效率是同等的 ,提示传输到结石的能量与碎石效率的相关性很好。而 10Hz、4min组的碎石效率比预期的略有下降 ,     

Dengue hemorrhagic fever is associated with polymorphisms in JAK1

To identify genes associated with the clinical presentation of dengue, 50 cases of probable or possible dengue hemorrhagic fever (DHF), 236 dengue fever (DF), and 236 asymptomatic infections were genotyped for 593 single-nucleotide polymorphisms (SNPs) in 56 genes across the type 1 interferon (IFN) response pathway as well as other important candidate genes. By single locus analysis comparing DHF with DF, 11 of the 51 markers with P<0.05 were in the JAK1 gene. Five markers were significantly associated by false discovery rate criteria (q<0.20 when P<6 × 10⁻⁴). The JAK1 SNPs showed differential distribution by ethnicity and ancestry consistent with epidemiologic observations in the Americas. The association remained significant after controlling for ancestry and income. No association was observed with markers in the gene encoding CD209 (DC-SIGN). An association between DHF and JAK1 polymorphisms is in agreement with expression profiles showing generalized decreased type 1 IFN-stimulated gene expression in these patients.     

Extrapancreatic spread of acute pancreatitis: new observations with real-time US

Real-time ultrasonography (US) was compared with abdominal computed tomography (CT) in 40 patients with moderate to severe acute pancreatitis. Emphasis was placed on the ability of US to disclose peripancreatic involvement of the anterior pararenal spaces, lesser sac, and transverse mesocolon. When a realtime US scanning technique emphasizing semierect patient positioning and coronal views was used, 20 of 26 lesions in the anterior pararenal space (77%) and 14 of 14 abnormalities in the lesser sac (100%) were visualized. Abnormalities in the transverse mesocolon, however, were poorly detected on US scans. Ten patients (25%) in the study had extrapancreatic abnormalities missed by US. CT remains the imaging method of choice in patients with clinically moderate to severe pancreatitis. In patients with mild pancreatitis, the real-time US technique we describe improved extra-pancreatic visualization compared with previous studies using static scanners. A new US observation of perivascular spread of acute pancreatitis around the splenic and portal veins is described.     

Deep venous thrombosis of the lower extremity: US evaluation

The sensitivity of duplex ultrasonography (US) for detecting deep venous thrombosis of the lower extremity was compared with that of venography in a prospective study of 54 patients. Doppler analysis of the common femoral vein and US imaging of the deep venous system from the common femoral vein to the popliteal vein was performed. Common femoral vein response to the Valsalva maneuver was recorded. Sonographically visible thrombi and abnormal vein compressibility were 91% sensitive for the common femoral vein, and 94% sensitive for the superficial femoral or popliteal veins, with no false-positive examinations. Abnormal Doppler flow and abnormal response of the common femoral vein to the Valsalva maneuver enabled thrombi to be detected only in the common femoral and iliac veins. Combined data allowed accurate diagnoses in all patients with deep venous thrombosis proximal to the deep calf veins. US should be the screening examination of choice for evaluating patients with suspected lower extremity deep venous thrombosis.