Interaction of Epstein-Barr viral (EBV) origin of replication (oriP) with EBNA-1 and cellular anti-EBNA-1 proteins

We have previously shown that 12-O-tetradecanoylphorbol-13-acetate (TPA) which activates expression of the latent genome of the Epstein-Barr virus (EBV) in Burkitt lymphoma cells induces the synthesis of two cellular anti-EBNA-1 competitor proteins, anti-EBNA-1.1 and anti-EBNA-1.2. Both anti-EBNA-1 proteins can uncouple the specific binding of the EBNA-1 to the region required for EBV plasmid maintenance (oriP). Here, we show by DNase I footprinting that the binding sites on oriP for the EBNA-1 and the anti-EBNA-1 proteins were indistinguishable. The proteins bound to the 30-bp tandem repeats of the oriP. Glycerol-gradient centrifugation and gel retardation assay revealed that a 60-kDa protein formed the anti-EBNA-1.1-DNA complex and a 40-kDa protein formed the anti-EBNA-1.2-DNA complex.     

Chronic intracranial pressure monitoring by telemetry: Clinical experience

Intracranial pressure (ICP) monitoring is a critical measure for avoiding severe brain dysfunction or brain death by directing supportive therapy so as to prevent ICP increase severe enough to reduce cerebral blood perfusion. Such situations occur with brain swelling, increased cerebral vascular volume, and increase in cerebrospinal fluid (CSF) volume. Causes include ischemic stroke, subarachnoid bleeding, brain contusion, encephalitis (as in Reye's syndrome), and hydrocephalus from meningitis or neoplasm. When several days of ICP monitoring can direct resolution of the pressure crisis, the invasive direct connection of an intracranial sensor with external recording device carries only minimal infection risk. Prolonged ICP monitoring for weeks or months demands telemetry and becomes desirable in a number of chronic disease problems including both congenital and acquired hydrocephalus where enlarged and pressurized cerebral ventricles develop with reduced absorption of continuously secreted CSF. Although the primary disturbance in CSF circulation can remain incurable, its palliation by valve-regulated CSF diversions or shunting can restore normal brain function and in infants permit normal brain development. Missing this goal can result from failure to maintain a sufficiently normal pattern of CSF dynamics and ICP. Monitoring of the CSF pressure fluctuations transmitted through an intraventricular catheter provides the most accurate record of ICP pulsations. Therefore, a pressure sensing module can be “T'd” into an existing shunt system in continuity with the already placed ventricular tube. The capacity to monitor ICP accurately by telemetry was first established in dogs made hydrocephalic to assure free CSF pulse through a ventricular catheter (1,2,3, 4,5). The subsequent use of ICP monitoring by telemetry in three patients will be described.     

Role of actin microfilament in osmotic stretch-induced increase of voltage-operated calcium channel current in guinea-pig gastric myocytes

 Using the whole-cell patch clamp technique, the role of actin microfilament in hyposmotic increase of voltage-operated calcium channel current (I _Ba) was studied in guinea-pig gastric myocytes. Hyposmotic superfusate (212 mOsm) increased peak I _Ba amplitude by 32.7 ± 6.5%; when cytochalasin-D (Cyt-D, 20 μM), an actin cytoskeleton disruptor, was used, an increase of only 9.7 ± 3.1% was seen. I _Baresponse to osmotic stress was potentiated (45.1 ± 4.1% increase) by 20 μM phalloidin, an actin microfilament stabilizer. However, colchicine (100 μM), an microtubule cytoskeleton disruptor, had no effect on either I _Ba or its response to hyposmotic solution. Phalloidin also induced a rightward shift of the I/V relationship of I _Ba, while Cyt-D itself had no effect. These results suggest that actin cytoskeleton may mediate hyposmotic stretch-induced I _Ba increase in gastric smooth muscle. Received: 26 March 1997 / Received after revision: 28 May 1997 / Accepted: 3 June 1997     

华南、华北人群HLA-DQB1等位基因多态性

目的从基因水平调查了中国华南、华北地区人群HLA-DQB1等位基因频率，并研究比较两地区人群HLA-DQB1多态性分布。方法采用深圳益生堂生物企业有限公司研制开发的“HLA-DQB1低分辨率分型基因芯片检测试剂盒”，应用聚合酶链反应．序列特异性引物＋序列特异性寡核苷酸探针芯片检测技术，对700名南方地区的中国人和320名北方地区的中国人进行基因分型。结果鉴定了10个HLA-DQB1等位基因，获得了一组准确、科学的统计数据。结论得到了中国华南、华北地区人群HLA-DQB1等位基因频率差异的数据，证明中国人群HLA-DQB1＊02，05，0601，0602，0603的分布南北差异有统计学意义（P〈0．05），为疾病相关性研究、人文科学研究提供了可靠的遗传学数据。     

Nitric Oxide Synthase Expression in Macrophages of Histoplasma capsulatum-Infected Mice Is Associated with Splenocyte Apoptosis and Unresponsiveness

Splenic macrophages from Histoplasma capsulatum-infected mice express inducible nitric oxide synthase (iNOS), and the iNOS expression correlates with severity of the infection. We examined whether production of NO is responsible for apoptosis and the anti-lymphoproliferative response of splenocytes from mice infected with H. capsulatum. In situ terminal deoxynucleotidyl transferase nick end labeling revealed apoptotic nuclei in cryosections of spleen from infected but not normal mice. Splenocytes of infected mice were unresponsive to stimulation by either concanavalin A or heat-killed H. capsulatum yeast cells. Splenocyte responsiveness was restored by addition to the medium of N^G-monomethyl-l-arginine, a known inhibitor of NO production. The proliferative response of splenocytes from infected mice was also restored by depletion of macrophages or by replacement with macrophages from normal mice. In addition, expression of iNOS returned to its basal level when the animals had recovered from infection. These results suggest that suppressor cell activity of macrophages is associated with production of NO, which also appears to be an effector molecule for apoptosis of cultured splenocytes from infected mice.

Nitric oxide (NO) has been reported to induce apoptosis in many cells including smooth muscle cells (20), oligodendrocytes (27), pancreatic β cells (11), melanoma cells (35), thymocytes (7), B lymphocytes (4), and macrophages (2). Fehsel et al. recently demonstrated apoptosis in freshly isolated thymocytes after exposure to NO (7). In the same report, they also showed apoptotic foci in close proximity to blood vessels after lipopolysaccharide treatment. Capillary endothelial and dendritic cells adjacent to apoptotic foci stained strongly for inducible nitric oxide synthase (iNOS), suggesting that NO may be the mediator for thymic apoptosis (7). Data from another laboratory also showed that cloned thymic stromal cell monolayers eliminate thymocytes in vitro through production of NO (26). Furthermore, apoptosis has been suggested as a mechanism by which the immune system replenishes itself and maintains homeostasis (30).The dimorphic fungus Histoplasma capsulatum is a facultative intracellular pathogen of the macrophage (32). Although it is not an obligate intracellular pathogen, the organism is found almost exclusively inside host cells during histoplasmosis (5). In our in vitro studies, H. capsulatum exhibits uninhibited growth in normal unstimulated murine macrophages (32). In activated macrophages, either peritoneal macrophages and cells from the Raw 264.7 line stimulated by gamma interferon (IFN-γ) or splenic macrophages stimulated by IFN-γ and lipopolysaccharide, growth of the fungus is inhibited (13, 18, 32). Furthermore, the anti-histoplasma activity of macrophages is dependent on the expression of iNOS and the production of NO (14, 18). However, the significance of NO production in immunoregulation of histoplasmosis is not clearly defined.In this study, we examined whether NO can act as a regulator of apoptosis in lymphoproliferative responses of splenocytes from H. capsulatum-infected mice. We showed that iNOS was induced in splenic macrophages during active infection and the expression of iNOS coincided with active infection. We also observed by in situ terminal deoxynucleotidyl transferase (TdT) nick end labeling (TUNEL) of spleen sections that apoptosis occurred in immune cells in the spleens of infected mice but was minimal in control mice. The link between apoptosis and NO production was established by inclusion of N^G-monomethyl-l-arginine (NMMA) in the culture medium. Inhibition of NO production reduced the amount of apoptosis in splenocyte culture. Thereby, we also confirmed the findings of Zhou et al. (36) that production of NO by splenocytes of H. capsulatum-infected mice suppressed the splenic lymphocyte proliferative response. In addition, we showed that macrophages were mediators of splenocyte unresponsiveness through the NO that they produced and that NO production was associated with apoptotic changes in cultured splenocytes from infected mice.     

Effect Of Pulsatile Electromagnetic Fields On Blood Viscosity And Coagulation

Ithasbeenprovedthatanumberofdiseasesarerelatedwithabnormalityofbloodviscosityandcoagulationinclinicalresearch.Bloodhyperviscosityandhypercoagulationcauseandaccelearatethedevelopmentofcertaindiseases,deathrateofsomeofwhicharerisingwithyears.Lookingforawaytoreducebloodviscosityandrestrainfasterandstrongercoagulationbecomesasubjectdrawingmoreattention.Theproperseofthisresearchwastofindsuchaway.Intheblood,therearechargrdRBC,WBC,PLT,inorganicions,sothattheremustbesensitiveandcomplicatedresponse…     

C1q受体研究进展

补体分子C1q具有调节各种细胞反应的能力.近年,随着C1q功能研究的深入,发现许多细胞内或者细胞表面存在结合C1q的蛋白或者受体,如C1qRp、gC1qbp、C1qRo2-、钙网素/CRT/cC1qR胶凝素受体、CR1.其中某些蛋白除结合C1q外还结合其它配体.     

Paternal mosaicism and hereditary angioedema in a Taiwanese family.

BACKGROUND: Hereditary angioedema (HAE) is a rare disorder characterized by recurrent attacks of localized subcutaneous or submucosal edema. It is inherited in an autosomal dominant fashion and caused by a deficiency of C1 inhibitor (C1 INH). Most patients with HAE have an absolute deficiency of C1 INH (type I HAE), whereas the rest (approximately 15%) synthesize a dysfunctional C1 INH protein (type II HAE). Mosaicism is rare in HAE. OBJECTIVE: To describe the clinical manifestations, laboratory findings, and molecular genetic studies in a Taiwanese family with type I HAE with paternal mosaicism. METHODS: A family that included a 34-year-old man (index patient) and his 25-year-old brother who both had recurrent peripheral angioedema was evaluated. A younger sister had died of an unexplained cause at 18 years of age. We analyzed blood levels of C3, C4, and C1 INH and sequenced the SERPING] (C1NH) gene that codes for C1 INH in 5 family members, including the parents and 3 brothers. RESULTS: The 4 men in the family had a novel mutation c.3_73del, p.N1fsX34 in exon 3 of the C1INH gene, resulting in C1 INH deficiency. Although the father carried this mutant gene, he had normal serum levels of C1 INH. Based on quantitative analysis of allele dosage by DNA fragment analysis (GeneScan), the father was determined to have genetic mosaicism. CONCLUSION: Parental mosaicism is a possible explanation for normal C1 INH plasma concentrations in both parents despite clinically apparent HAE in the children.