Molecular characterization of a glycosylphosphatidylinositol-linked ADP- ribosyltransferase from lymphocytes

Mono ADP-ribosyltransferases catalyze the transfer of the ADP-ribose moiety of nicotinamide adenine dinucleotide (NAD) to proteins. It was reported by Wang et al (J Immunol 153:4048, 1994) that incubation of mouse cytotoxic T lymphocytes (CTL) with NAD resulted in the ADP- ribosylation of membrane proteins and inhibition of cell proliferation and cytotoxicity. Treatment of CTL with phosphatidylinositol-specific phospholipase C (PI-PLC) before incubation with NAD prevented the inhibitory effects of NAD on the cells, consistent with the removal of a glycosylphosphatidylinositol (GPI)-anchored ADP-ribosyltransferase on the lymphocyte surface. We have identified and cloned a GPI-linked ADP- ribosyltransferase from Yac-1 mouse T-cell lymphoma cells. The deduced amino acid sequence of the Yac-1 transferase was 70% and 41% identical to those of the rabbit skeletal muscle and chicken heterophil, respectively. It contained three noncontiguous sequences similar to those found in several of the bacterial toxin and vertebrate ADP- ribosyltransferases. Based on crystallography of the bacterial toxins, these regions are believed to form, in part, the catalytic site consistent with a common mechanism for the ADP-ribose transfer reaction. In rat mammary adenocarcinoma (NMU) cells transformed with the Yac-1 transferase cDNA, transferase activity was present on the cell surface and was released into the medium by treatment of cells with PI-PLC. Thus, we have cloned a novel gene that has properties identical to the transferase detected in CTL, and may be involved in the NAD-dependent regulation of proliferation and cytotoxicity.     

Molecular phenotype of a human lymphoblastoid cell-line homoplasmic for the np 7445 deafness-associated mitochondrial mutation

We have studied mitochondrial gene expression and metabolic function in a human lymphoblastoid cell-line homoplasmic for the np 7445, deafness- associated mitochondrial DNA mutation. The mutation maps to the 3' termini of the oppositely oriented genes encoding cytochrome oxidase subunit I (COI) and tRNA-ser(UCN). In comparison with control lymphoblastoid cells, we detected a marked depletion (> 60%) of tRNA- ser(UCN). There was, however, no significant impairment of respiratory function, no alteration to the structure or abundance of COI mRNA or its precursors, and no detectable abnormality of mitochondrial protein synthesis. We also found considerable tissue-variation in the abundance of tRNA-ser(UCN). We propose that the tissue-specific phenotype associated with this mutation results from an inherent deficiency in the processing of the mutant pre-tRNA, that becomes limiting for protein synthesis only in a restricted set of cells of the auditory system in which the tRNA is, for other reasons, already at a critically low level.      

Sources and sequelae of bacterial contamination of hematopoietic stem cell components: implications for the safety of hematotherapy and graft engineering

Background: It is important to compare the incidence of bacterial contamination of components collected from the peripheral blood or bone marrow (BM), as well as of components processed with or without cell selection or depletion, and to evaluate the sequelae of such contamination. Study Design and Methods: Bacterial contamination rates were compared in 1380 untreated autologous peripheral blood progenitor cells (PBPCs), 291 untreated autologous BM samples, 916 monoclonal antibody (MoAb)-treated autologous and allogeneic BM samples, and in 45 autologous PBPC components from which the CD34+ cells were selected. Bacterial cultures were performed at sequential time points during the processing of MoAb-treated BM. Results: Bacterial contamination was documented in 44 of 2632 components from 1593 patients (1.67% of components, 2.76% of patients) before cryopreservation. Although only 0.65% of untreated PBPCs were contaminated before cryopreservation, each patient was more likely to have given a contaminated PBPC component than a contaminated BM component (2.41% vs. 0%, p < 0.01). Bacterial contamination of MoAb-treated BM was greater during or after manipulation than it was before (2.33% vs. 0.77%, p < 0.05). At thawing, contamination was documented in 42 (1.97%) of 2136 components cultured. Ten (13.7%) of 73 patients who received hematopoietic progenitor cells that were contaminated before cryopreservation or at thawing developed fever or positive blood cultures within 48 hours of transfusion. Fever was associated with bacteremia in two cases, but no irreversible clinical sequelae were noted. Conclusion: These studies suggest that, despite careful attention to sterile procedures, low-level contamination of hematopoietic stem cell components can be introduced before or during manipulation as well as at thawing, and that standards for monitoring of the procedures for collection, processing, cryopreservation, thawing, and transfusion of hematopoietic progenitor cells are necessary.     

Opioid signalling in the rat rostral ventrolateral medulla

1. The present article reviews several aspects of opioid signalling in the rostral ventrolateral medulla (RVLM) and their implications for the neural control of blood pressure. 2. In the RVLM, preproenkephalin (PPE) mRNA is expressed by bulbospinal cells that are strongly barosensitive. These putative presympathetic neurons includes C1 and non-C1 neurons. 3. In the RVLM, PPE mRNA is also present in GABAergic neurons that do not project to the thoracic spinal cord. 4. Rostral ventrolateral medulla presympathetic cells receive enkephalinergic inputs and express mu-opioid receptors (MOR). Some of their synaptic inputs also contain MOR. 5. Pre- and post-synaptic modulation of RVLM presympathetic neurons by MOR agonists has been demonstrated in slices of neonate brain. The post-synaptic effect is inhibitory (increased gK). Presynaptic effects include disfacilitation (reduction of glutamate release) and possibly dishinhibition (reduction of GABA release). 6. In conclusion, opioid signalling plays a pervasive role in the medullospinal network that controls sympathetic tone and arterial pressure. Opioid peptides are made by the presympathetic, presumably excitatory, cells of the RVLM and by local GABAergic inhibitory neurons. In addition, RVLM presympathetic neurons are also controlled by opioid peptides at the pre- and post-synaptic level. mu-Opioid receptors are found post-synaptically, whereas presynaptic receptors probably include both mu and delta subtypes. Conditions that trigger the release of opioid peptides by presympathetic neurons or by inputs to these cells are not fully understood and may include decompensated haemorrhage and certain types of peripheral sensory stimulation related to acupuncture.     

丹参通络解毒汤联合内皮祖细胞移植对心肌缺血再灌注损伤大鼠促血管新生作用的研究

目的探讨丹参通络解毒汤(DSTLJD)联合内皮祖细胞(endothelial progenitor cells, EPCs)移植对心肌缺血再灌注损伤(ischemic reperfusion injury, IRI)模型大鼠促血管新生作用的影响及其机制。方法采用密度梯度离心法及差数贴壁法分离和培养EPCs,采用免疫荧光法鉴定EPCs。通过结扎左冠状动脉左前降支的方法建立IRI模型,采用随机数字表法分为SH组(假手术组)、IRI组(模型组)、EPCs组(EPCs移植组)、DSTLJD组(丹参通络解毒汤组)、DSTLJD+EPCs组(丹参通络解毒汤+EPCs移植),每组10只。4周后,采用HE染色法观察心肌组织的病理形态,用免疫组化法测定各组大鼠心肌微血管计数(microvessel count, MVC)、心肌微血管密度(microvessel density, MVD),并检测各组大鼠血管内皮生长因子(vascular endothelial growth factor, VEGF)、碱性成纤维生长因子(basic fibroblast growth factor, bFGF)的蛋白表...     

组成型αB晶体蛋白在热休克蛋白核转录因子1敲除小鼠心肌中的表达

目的:了解热休克蛋白核转录因子1(HSF1)对小鼠心肌组成型αB晶体蛋白(αB-Crystallin,αBC)表达的影响.方法:用western blot和免疫组织化学的方法,测定组成型αBC在HSF1基因野生型(hsf1+/+)和HSF1基因敲除型(hsf1-/-)小鼠心肌中的表达.结果:αBC在hsf1-/-和hsf1+/+小鼠心肌表达量分别为68.42±4.16和100.00±7.58(心肌可溶性组分,P＜0.05),20.35±1.01和37.55±1.91(心肌不可溶性组分,P＜0.05);免疫组化显示αBC在hsf1-/-心肌细胞内的表达信号较hsf1+/+明显减弱.结论:HSF1基因是介导组成型αBC基因表达重要的、但不是惟一的因子.     

Need for recovery from work in relation to age: a prospective cohort study

Purpose  

To investigate the impact of increasing age on the need for recovery (NFR) over time among day workers     

Effective treatment of painful bone crises in type I gaucher's disease with high dose prednisolone

In type I Gaucher's disease, episodes of severe disabling bone pain, the so called bone crises, may be resistant to all analgesics, including narcotics. The demonstration of subperiosteal oedema on magnetic resonance imaging (MRI) led to an attempt to use steroids to relieve the oedema and thereby the pain. On eight occasions, five patients with documented bone crises received conventional dose steroids (20 mg/m2/day) with considerable shortening of the attacks. On six occasions five further patients received high dose methylprednisolone (30 mg/kg intravenously or 1 g/m2 orally daily for two days), which was followed by oral prednisone for three to five days on the last four occasions. In this later group, pain relief was evident within several hours. Three treatments were given on an ambulatory basis. The MRI scan of one of these patients showed no subperiosteal fluid collection five days after high dose steroids had been started, and on subsequent x ray examination, there was no periosteal elevation. This treatment should be considered in cases of Gaucher's disease with bone crises.