Application of rearrangements of T cell receptor gene in the diagnosis of mediastinal T-lymphoblastic lymphoma: a case report

Liver veno-occlusive disease is a severe toxic effect observed after bone marrow transplantation. Clinical manifestations are jaundice, painful liver enlargement, and fluid-sodium retention. Histologically there is non-thrombotic obliteration of the centro-lobular veins associated with centro-lobular necrosis. This severe complication of bone marrow transplantation occurs early and is caused by a toxic processing effect. Incidence is variable, 2 to 50% in reported series, depending on patients, type of marrow provessing and on diagnostic criteria (which hinders comparison between studies). According to most studies, veno-occlusive disease regresses spontaneously. Mortality, depending on the severity of the symptoms, varies from 20 to 50%. Pathogenesis remains under debate: the initial event would occur in the sinusoid endothelium creating a state of local hypercoagulability by release of tissue factors favoring deposit of coagulation factors, especially factor VIII, in the subendothelial region of the veinules. There is also a direct toxic effect on centro-lobular hepatocytes which is further aggravated by ischemia and venous stasis. use of heparin to prevent veno-occlusive disease was proposed by the Besan?on group in 1985 after they observed a low incidence (1 case in 65) in patients who were given low doses of heparin to maintain patent central catheters. The same team confirmed in 1992 the low incidence in a large retrospective series of 444 patients given either an autograft (3 cases in 253 patients, i.e. 1.2%), or an allograft (5 cases in 191 patients, i.e. 2.6%). Two single-center studies, one in Seattle and the other at the Saint-Antoine hospital in Paris, published in 1990 and 1991, did not show any difference in patients given heparin or not. Inversely, a randomized study published by Attal in 1992 including 161 patients showed a significant difference in the incidence of veno-occlusive disease between patients given heparin (2.5%) and those who were not given heparin (13.7%; p < 0.01). All these studies show that with low doses (100-150 U/kg) the risk is very very low. The mechanism of action of heparin would appear to be related to its protective effect on the endothelium rather than its hemostasis effect. The vascular protective effect of prostaglandin E1 suggests it might also be useful in preventing veno-occlusive disease.     

ZrV1.5Ni1.5 as electrode material in nickel-metal hydride batteries An in situ scanning tunnelling microscopy investigation

We have investigated the alloy ZrV_1.5Ni_1.5 by means of scanning electron microscopy (SEM) with electron probe X-ray microanalysis (EPMA), X-ray diffraction (XRD), in situ STM (scanning tunnelling microscopy in an electrolyte under controlled electrochemical potential) and electrochemical charge discharge measurements. By means of EPMA we found that the alloy is composed of three different crystallographic phases. The main phase (≈75 vol.%) is ZrV_0.81Ni_1.47, the second phase (≈20 vol.%) is V₉₂Ni₈ and the third (≈5 vol.%) is a ZrNi based phase. Using in situ STM we investigated the different corrosion behaviour of the phases. At a potential of −600 mV versus the Hg/HgO reference electrode we observed the corrosion of the vanadium rich phase while the other two phases passivated.     

A new hydrogen storage electrode

This paper presents experimental evidence that it is possible to use a cathodic charge to store hydrogen on compounds such as LaNi₅. Using an alkaline medium (KOH 5N) in an unpressurized system at 20°C, the mass capacity was found to be approximately 330 mAH/g (5H/mol LaNi₅). Comparison of these results with the solid-gas isotherms indicated that the hydrogen is held in a non-equilibrium state.The influence of temperature, stoichiometry and substitution in the LaNi₅ on the capacity are presented.     

高压IGBT和二极管SOA性能的突破——SSCM

介绍了一种新型高压IGBT和二极管设计平台,它展现出目前安全工作区域SOA(Safe Operation Area,简称SOA)所能达到的最高极限.首次展示了一种额定电压3.3～6.5kV、能够同时承受动态雪崩和开关自箝位模式(SwitchSelf Clamp Mode,简称SSCM)、低损耗的IGBT和二极管芯片组.这项成果将促成高压器件SOA能力的全新突破.     

Synthesis of carbon nanotubes over Fe catalyst on aluminium and suggested growth mechanism

Carbon nanotubes (CNTs) have been grown by the decomposition of C₂H₂ over a thin catalyst film in order to investigate the growth mechanism of CNTs by chemical vapour deposition (CVD). The catalyst was prepared from an iron nitrate precursor solution that was spin-coated on an aluminium substrate. The density (mg cm⁻²) and the length of the CNTs were greatly influenced by the precursor concentration, the time of deposition, the temperature and the ratio of C₂H₂:N₂. Scanning and transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction measurements have been carried out in order to investigate the behaviour of the catalyst before and during the growth process. The iron nitrate film formed an amorphous iron oxide layer that transformed to crystalline Fe₂O₃, which was reduced to Fe₃O₄ and FeO in contact with the C₂H₂: N₂ reaction atmosphere. The CNTs synthesis took place on small iron carbide (Fe₃C) particles that were formed from the FeO.     

TNF-alpha and IFN-gamma render microglia sensitive to Fas ligand-induced apoptosis by induction of Fas expression and down-regulation of Bcl-2 and Bcl-xL

The immune response in the central nervous system (CNS) involves microglial cells which represent intraparenchymal antigen-presenting cells (APC). To control immune effector mechanisms it may be required to induce apoptosis of APC and thereby limit reactivation of T cells that have invaded the CNS. In the present study we investigated the susceptibility of primary murine microglia and of the murine microglial cell line BV-2 to undergo Fas-mediated apoptosis. Whereas resting microglia are resistant to Fas ligand (FasL) treatment, induction of FasL-mediated apoptosis was achieved by treatment with TNF-alpha or IFN-gamma. The effect of these cytokines was paralleled by up-regulation of Fas expression and down-regulation of Bcl-2 and Bcl-xL but not Bax. Activation of microglia by TNF-alpha and IFN-gamma was also accompanied by increased amounts of mRNA for the apoptosis inhibitor FLIP, an effect which did not protect the cells from FasL-induced apoptosis. The FasL-induced cell death pathway in microglia involves reactive oxygen intermediates because the antioxidants N-acetylcysteine and glutathione interfere with induction of apoptosis. Surprisingly, microglia constitutively express FasL on the cell surface. However, blocking of endogenous Fas-FasL interaction with Fas-Fc fusion protein did not enhance the survival of microglia, excluding the possibility of suicide or fratricide mechanisms. By their expression of FasL and their TNF-alpha/IFN-gamma-dependent sensitivity to the pro-apoptotic effect of exogenous FasL, microglial cells may influence the course of T cell-mediated diseases of the CNS.     

Apoptosis induced by sulindac sulfide in epithelial and mesenchymal cells from human abdominal neoplasms

A tadpole of bullfrog, Rana catesbeiana, is originally covered with the larval skin over its entire body. Drastic changes arise in both the epidermis and the subcutaneous connective tissue at an early developmental stage, producing the precursor of adult type skin (pre-adult skin). It was found that calcium is a useful probe to detect the region where the precursor formation has occurred because its deposition in the upper part of subcutaneous collagen bundles coincides with the appearance of the pre-adult skin. Whole-mount in situ staining of tadpoles with alizarin red S revealed the initiation site of the premetamorphic transformation of the larval skin into the adult precursor and its ensuing region-dependent expansion. The pre-adult skin first emerged at TK II to III (TK, Taylor and Kollros staging) t lateral sides of the body, which led us to postulate that 'the center for premetamorphic skin transformation' is formed at the specific site in this region. This center moved dorsally and then ventrally, then reached to the most proximal region of the tail, yielding a unique sequential conversion pattern by around TK V when the conversion was completed in the trunk. The present study also visualized the process of the hindlimb skin transformation.