Blood vessel location time by Anopheles stephensi (Diptera: Culicidae).

Probing behavior of Anopheles stephensi Liston is characterized by the following: the first probe is longer than subsequent ones, the probability of blood location rises initially and then falls, and blood vessel location is deterministic. The overall probing behavior of An. stephensi, therefore, is similar to that of Aedes aegypti (L.); i.e., differences between them were quantitative and may be accounted for by different levels of salivary apyrase and different experimental vertebrate hosts.     

Long-term anti-CD4 treatment of MRL/lpr mice ameliorates immunopathology and lymphoproliferation but fails to suppress rheumatoid factor production

MRL/lpr mice were treated with anti-CD4 mAb to define the role of CD4+ T cells in the pathogenesis of autoimmune disease and the lymphoproliferation characteristic of the strain. Anti-CD4 treatment was not associated with adverse effects, and survival of treated mice was increased over that of rat IgG-treated controls. Renal function was preserved, and the histologic severity of glomerulonephritis was minimal in treated mice. Lymphoid tissues of mice receiving anti-CD4 were effectively depleted of CD4+ T cells, and lymphoproliferation was markedly reduced. Serum IgG, anti-Sm, and anti-dsDNA levels were reduced significantly, while serum IgM and IgM rheumatoid factor levels were unaffected by anti-CD4 treatment. These data show that in MRL/lpr mice lymphoproliferation, renal disease, anti-Sm and anti-dsDNA antibody production, and elevated IgG levels are all linked to CD4+ T cell function. In contrast, both total IgM and IgM rheumatoid factor production appear to be the result of B-cell activity that is not regulated by CD4+ T cells.     

血管内皮生长因子反义基因转染对高转移人巨细胞肺癌细胞系生 …

目的 探讨反义血管内皮生长因子（ＶＥＧＦ）基因转染在抑制恶性肿瘤生长和转移的抗肿瘤血管基因治疗中的意义。方法 利用基因重组技术构建正义和反义ＶＥＧＦ１２１ ｃＤＮＡ真核表达载体,用脂质体法转染高转移性人巨细胞肺癌细胞（ＰＧ）,经Ｎｏｒｔｈｅｍ杂交和Ｗｅｓｔｅｒｎ印迹免疫化学检测ＶＥＧＦ ｍＲＮＡ和蛋白质的表达水平,并对转染前后细胞进行体外生长和裸鼠体内生长转移等多项生物学行为实验,结果 转染反义转     

Identification of novel regions of allelic loss from a genomewide scan of esophageal squamous-cell carcinoma in a high-risk Chinese population

Esophageal cancer is one of the most common fatal cancers worldwide. Deletions of genomic regions are thought to be important in esophageal carcinogenesis. We conducted a genomewide scan for regions of allelic loss using microdissected DNA from 11 esophageal squamous-cell carcinoma patients with a family history of upper gastrointestinal tract cancer from a high-risk region in north central China. Allelic patterns of 366 fluorescently labeled microsatellite markers distributed at 10-cM intervals over the 22 autosomal chromosomes were examined. We identified 14 regions with very high frequency (>/= 75%) loss of heterozygosity (LOH), including broad regions encompassing whole chromosome arms (on 3p, 5q, 9p, 9q, and 13q), regions of intermediate size (on 2q, 4p, 11p, and 15q), and more discrete regions identified by very high frequency LOH for a single marker (on 4q, 6q, 8p, 14q, and 17p). Among these 14 regions were 7 not previously described in esophageal squamous-cell carcinoma as having very high frequency LOH (on 2q, 4p, 4q, 6q, 8p, 14q, and 15q). The very high frequency LOH regions identified here may point to major susceptibility genes, including potential tumor suppressor genes and inherited gene loci, which will assist in understanding the molecular events involved in esophageal carcinogenesis and may help in the development of markers for genetic susceptibility testing and screening for the early detection of this cancer. Genes Chromosomes Cancer 27:217-228, 2000. Published 2000 Wiley-Liss, Inc.     

Tyrosine phosphorylation of a low molecular weight protein induced by RANTES in T-lymphocytes

The beta-chemokine RANTES, a T-lymphocyte activator, chemoattractant, and inducer of homotypic aggregation, is considered to exert extensive effects on T lymphocytes through either G protein-coupled or protein tyrosine kinase (PTK) signaling pathway. In the present study, we analyzed RANTES-induced signal transduction through PTK as an early event in T-lymphocyte activation. Tyrosine phosphorylation is detected by immunoblots in the human T-cell line H9 after incubation with human recombinant RANTES. The tyrosine phosphorylation of a protein with a molecular mass of about 25 kD is measurable as early as 30 s and maximal at 1-5 min; and is a dose-dependent effect. The phosphorylation response can be abrogated by the tyrosine-kinase inhibitor herbimycin A (HA) but is insensitive to heterotrimeric Galphai protein inhibitor pertussis toxin (Ptx). This phenomenon is also observed in a visible homotypic aggregation response after incubation serum-starved H9 cells with RANTES. The phosphorylation response can not be down-regulated by preincubation with either anti-CC chemokine receptor 5 (CCR5) antibody or HIV-1Bal supernatants. Our results suggest that tyrosine phosphorylation of a protein with molecular mass of about 25 kD via Src-family PTK(s) is an early event in T-lymphocyte activation associated with the homotypic aggregation in response to RANTES.     

Mechanisms of T cell-induced glomerular injury in anti-glomeruler basement membrane (GBM) glomerulonephritis in rats

The effector mechanisms of T cell-dependent acute glomerular injury were studied in autologous phase anti-GBM glomerulonephritis (GN) in rats. Acute proliferative GN was induced in sensitized rats by a subnephritogenic dose of sheep anti-rat GBM antibody. Injury was manifested by proteinuria and glomerular leucocyte infiltration composed predominantly of macrophages but also CD4⁺ and CD8⁺ T cells. T cell depletion, using an anti-CD5 MoAb, demonstrated that glomerular leucocyte infiltration and proteinuria were T cell-dependent. Inhibition of T helper cell function using an anti-CD4 MoAb prevented proteinuria and glomerular macrophage and CD4⁺ T cell influx, but not accumulation of CD8⁺ T cells. Depletion of CD8⁺ T cells also prevented proteinuria and the influx of macrophages and CD8⁺ T cells, but not accumulation of CD4⁺ T cells. Macrophage depletion, using micro-encapsulated clodronate, prevented proteinuria and glomerular macrophage infiltration, but not the accumulation of CD4⁺ or CD8⁺ T cells, indicating that macrophages are the common cellular effectors for both CD4 and CD8 T cell-dependent injury. Evidence for cytotoxic mechanisms of injury (increased numbers of apoptotic cells or accumulation of natural killer (NK) cells in glomeruli) could not be demonstrated. These data suggest that acute glomerular injury in anti-GBM GN is the result of macrophage recruitment, which is dependent on both CD4 and CD8 T cells, and that direct T cell-mediated injury (cellular cytotoxicity) is not involved.     

Cocrystallization of an immunoglobulin light chain dimer with bis(dinitrophenyl) lysine: tandem binding of two ligands, one with and one without accompanying conformational changes in the protein

Previous studies showed that the Mcg dimer of immunoglobulin light chains bound bis(dinitrophenyl)lysine both in trigonal crystals and in solution. On prolonged storage in ammonium sulfate, mixtures of ligand and protein produced small trigonal cocrystals in low frequency. These crystals were nearly isomorphous with those of the unliganded dimer in which the subunits were covalently linked by an interchain disulfide bond. By difference Fourier analyses at 3.5 A resolution and subsequent crystallographic refinement, the cocrystals were found to contain molecules with two ligands aligned in tandem along the interface of the variable (V) domains of the protein. One ligand molecule adopted an almost fully extended conformation, with the epsilon-DNP ring situated near the floor, the alpha-carboxyl group directed toward the solvent at the entry, and the alpha-DNP ring outside the rim of the main cavity. As if architecturally designed, the ligand was located symmetrically between the two domains in an orientation that was compatible with both the unaltered structure of the cavity lining and with the known crystal packing interactions of neighboring protein molecules. The second ligand molecule in the cocrystal lodged in the deep pocket immediately under the floor of the main cavity. The ligand adopted a very compact conformation with the two DNP rings roughly antiparallel to each other. This molecule appeared to be semi-permanently sequestered in the pocket since it could not be dislodged by exhaustive perfusion with ammonium sulfate crystallizing media. Relative to its volume in the native dimer, the pocket was expanded to accommodate the oversized ligand. Within a single protein molecule, therefore, two types of binding of a flexible ligand were observed, one with and one without accompanying conformational changes in the protein. The number of cocrystals which could be produced was markedly increased if the interchain disulfide bond between the Mcg monomers was first reduced and alkylated.     

Microsatellite analysis of synchronous and metachronous tumors: a tool for double primary tumor and metastasis assessment.

Despite well-established histopathological features and the development of immunostaining of human neoplasms, there are a number of cases in which surgical pathologists cannot assure the origin of synchronous and metachronous tumors. In many cases, the classification of these lesions as either two separate primary tumors or as a single primary tumor with a metastasis has significant implications with respect to patient prognosis and recommendations for therapy. To establish the origin of tumors, we assessed tumor cell clonality using PCR-based microsatellite analysis on microdissected archival tissues for loss of heterozygosity (LOH) and microsatellite instability (MSI) in a series of 19 paired synchronous and metachronous tumors from several organs. As a control group, 15 autopsy cases with an unequivocally recognizable primary tumor and associated metastases were also examined. Based on LOH and MSI findings, and using a panel of 4 to 12 (median 7) microsatellite markers, we were able to establish the clonal pattern of microsatellite changes in 17 out of 19 (89%) biopsy cases and thus determine if they were either double primary tumors (41%) or metastases (59%). Of interest, identical or similar pattern of microsatellite abnormalities were detected in 15 primary tumors and corresponding metastasis from autopsies. Our results indicate that microsatellite analysis for LOH and MSI, as an expression of clonality, provides a useful tool to distinguish double primary neoplasms and metastases in synchronous and metachronous tumors.