Multiple transformation phenotypes among revertants of temperature-sensitive mutants in the type 5 adenovirus DNA-binding protein

Seven independently isolated revertants of temperature-sensitive mutants in the 72K protein of Ad5 were tested for the ability to transform rat cells under a variety of conditions. Using the continuous cell line designated CREF, at 36° the range of transformation phenotypes of the different revertants included a frequency characteristic of WT and also the elevated frequency associated with the parental temperature-sensitive alleles. Transformation frequency did not correlate with other phenotypes, such as plaque size or plaquing efficiency on HeLa cells at 38.5°–39°. Therefore, although it is likely that the 72K protein modulates transformation, it is possible to dissociate genetically this regulatory function of the protein from its replicative function in permissive infection.     

Multiple sclerosis retrovirus particles and recombinant envelope trigger an abnormal immune response in vitro, by inducing polyclonal Vbeta16 T-lymphocyte activation

A retroviral element (MSRV) defining a family of genetically inherited endogenous retroviruses (HERV-W) has recently been characterized in cell cultures from patients with multiple sclerosis (MS). To address the possible relationship with MS, direct detection of circulating virion RNA was proposed but revealed technically difficult to perform in standardized conditions, in the face of multiple endogenous HERV-W copies. A parallel approach has evaluated MSRV potential pathogenicity in relation to characteristic features of multiple sclerosis, in particular, T-lymphocyte-mediated immunopathology. We report here that MSRV particles induce T-lymphocyte response with a bias in the Vbeta16 chain usage in surface receptor, whatever the HLA DR of the donor. A recombinant MSRV envelope-but not core-protein reproduced similar nonconventional activation. Molecular analysis of Vbeta CDR3 showed that Vbeta16 expansions are polyclonal. Our results thus provide evidence that MSRV envelope protein can trigger an abnormal immune response with similar characteristics to that of superantigens.     

Differential regulation of IL-13 and IL-4 production by human CD8+ and CD4+ Th0, Th1 and Th2 T cell clones and EBV-transformed B cells

In the present study, the requirements and characteristics forthe production of IL-13 by human T cells, T cell clones andB cells were determined and compared with those of IL-4. IL-13was produced by human CD4⁺ and CD8⁺ T lymphocyte subsets isolatedfrom peripheral blood mononuclear cells and by CD4⁺ and CD8⁺T cell clones. CD4⁺ T cell clones belonging to T_h0, T_h1-likeand T_h2-like subsets produced IL-13 following antigen-specificor polyclonal activation. In addition, EBV-transformed B celllines expressed IL-13 mRNA and produced small amounts of IL-13protein. Expression of IL-13 mRNA and production of IL-13 proteinby peripheral blood T cells and T cell clones was induced rapidlyand was relatively long lasting, whereas IL-4 production bythese cells was transient In addition, IL-13 mRNA expressionwas induced by modes of activation that failed to induce IL-4mRNA expression. IL-13 shares many biological activities withIL-4 which Is compatible with the notion that the IL-13 andIL-4 receptors share a common component required for signaltransduction. However, IL-13 lacks the T cell-activating propertiesof IL-4. Here we have shown that this is related to the factthat T cells fall to bind radiolabeled IL-13 and do not expressthe IL-13-speclflc receptor component Taken together, theseresults indicate that the differences In expression and biologicalactivities of IL-4 and IL-13 on T cells may have consequencesfor the relative roles of these cytokines In the immune response.     

Kallmann syndrome: 14 novel mutations in KAL1 and FGFR1 (KAL2)

Kallmann syndrome (KAL) combines hypogonadotropic hypogonadism and anosmia. Hypogonadism is due to Gonadotropin Releasing Hormone (GnRH) deficiency and anosmia is related to hypoplasia of the olfactory bulbs. Occasional symptoms include renal agenesis, bimanual synkinesia, cleft lip palate, dental agenesis. KAL is genetically heterogeneous and two genes have so far been identified, namely KAL1 (Xp22.3) and FGFR1/KAL2 (8p12), which underlie the X chromosome‐linked form and an autosomal dominant form of the disease, respectively. We studied a cohort of 98 unrelated Caucasian KAL patients. We identified KAL1 mutations in 14 patients, of which 7 (c.3G>A (p.M1?), g.IVS1+1G>T, c.570_571insA (p.R191fsX14), c.784G>C (p.R262P), c.958G>T (p.E320X), c.1651_1654delinsAGCT (p.P551_E552delinsSX), c.1711T>A (p.W571R)) have not been previously reported. In addition, we found FGFR1 mutations in 7 patients, namely c.303G>A (p.V102I), C.385A>C (p.D129A), c.810G>A (p.V273M), c.1093_1094delAG (p.R365fsX41), c.1561G>A (p.A520T), c.1836_1837insT (p.Y613fsX42), c.2190C>G (p.Y730X), all of which were novel mutations. In this study, unilateral renal agenesis and bimanual synkinesia were exclusively found associated with KAL1mutations, cleft palate and dental agenesia with FGFR1mutations. © 2004 Wiley‐Liss, Inc.     

Rapid detection of Clostridium difficile toxin A in stool specimens

Objective: To evaluate a rapid (15-min) enzyme immunoassay in the format of an individual cassette (ImmunoCard toxin A, Meridian, BMD, Marne-la-Vallée, France) for the detection of Clostridium difficile toxin A in stool specimens.
Methods: We compared this new test with the cytotoxicity assay using MRC-5 cells, the ToxA test (TechLab, BioWhittaker, Fontenay-sous-bois, France) and toxigenic culture for the diagnosis of C. difficile -associated diseases (CDAD). A total of 236 stool specimens collected from 220 patients was simultaneously tested with the four methods. Discordant results were resolved by reviewing patients' clinical records.
Results: The prevalence of CDAD was 13.9%. Test sensitivities and specificities were 100% and 99% respectively for the cytotoxicity assay, 87.5% and 100% for ImmunoCard toxin A, 77.4% and 100% for the ToxA test and 100% and 98% for toxigenic culture.
Conclusions: The ImmunoCard Toxin A is a very rapid, individual and easy-to-perform test for the diagnosis of CDAD. It provides same-day results and may be useful for both guiding appropriate treatment and controlling nosocomial spread of C. difficile.     

Prognostic values of galectin-3 and the macrophage migration inhibitory factor (MIF) in human colorectal cancers.

This study aims to investigate whether the immunohistochemical levels of expression of galectin-3 and the macrophage migration inhibitory factor (MIF) are associated with prognostic values in human colorectal tumors. This was performed on 99 specimens including 69 colorectal tumors (17 Dukes A, 19 Dukes B, 15 Dukes C and 18 metastatic tumors that we labeled as D), 10 hepatic metastases from colorectal cancers and 20 normal specimens (biopsies). The immunohistochemical levels of expression of MIF and galectin-3 were quantified on routine histological slides by means of computer-assisted microscopy. Separate analyses were performed on epithelial and connective tissue. The levels of expression of both MIF and galectin-3 were very significantly higher in epithelial tumor tissue when compared with normal epithelial specimens. A positive and significant correlation between MIF and galectin-3 expression was evidenced in connective tumor tissue, and in particular in the cases associated with short survival periods (less than 5 years). In the case of the Dukes A or B tumors, we established two new prognostic groups (labeled I and II) on the basis of the levels of galectin-3 expression measured in the tumor epithelium. In the case of the Dukes C or D tumors, we established two other prognostic groups (labeled III and IV) on the basis of the levels of MIF expression measured in the connective tissue. Kaplan-Meyer analyses confirmed the additional prognostic values (as compared with conventional clinical staging) given by this new classification (groups I to IV). They show that the Dukes A or B tumors characterized by low levels of galectin-3 expression in the tumor epithelium are associated with significantly better prognoses than those characterized by high levels. In addition, the Dukes C or D tumors characterized by high levels of MIF expression in the connective tumor tissue are associated with significantly better prognoses than those characterized by low levels. In conclusions, MIF and galectin-3 expression levels in colorectal tumors are related to their levels of biological aggressiveness. These markers could be used to identify patients at risk, for whom more aggressive adjuvant therapy seems to be indicated.     

Potential cancer therapy with the fragile histidine triad gene: review of the preclinical studies.

CONTEXT: The fragile histidine triad gene (FHIT) encompasses a human common fragile site, FRA3B, that is susceptible to environmental carcinogens. Deletion and inactivation of FHIT have been seen in a number of human premalignant and malignant lesions. OBJECTIVE: To review and evaluate preclinical studies of cancer therapy using the FHIT tumor suppressor gene and related studies involving Fhit protein expression. DATA SOURCES: A MEDLINE search of articles published from 1996 to June 2001 was performed; article reference lists were used to retrieve additional relevant articles. STUDY SELECTION: Immunohistochemical studies of primary tumors or relevant lesions were selected to evaluate Fhit expression in premalignant or malignant stages. Preclinical studies on antitumorigenic or therapeutic introduction of FHIT were reviewed for the effects of exogenous Fhit expression. For the immunohistochemical analyses, 26 studies were included that analyzed at least 15 cases of a single type of tumor. For precancerous lesions, 9 studies were included that analyzed at least 4 cases. For studies of FHIT introduction, 9 published studies were included. DATA EXTRACTION: Using primary data from each of the studies, we assessed the rationale and potential contribution of FHIT cancer therapy. Data was independently abstracted by 2 authors and study quality was assessed by 2 other authors. DATA SYNTHESIS: Overall, 60% (1162/1948 cases) of primary tumors showed absent or markedly reduced Fhit protein expression in cancer cells. Studies of preneoplastic lesions or early-stage cancer showed absence or marked reduction of Fhit protein expression in 0% to 93% of samples (overall, 31% [127/408 cases]). Preclinical studies using 26 cancer-derived cell lines from human lung, head and neck, esophageal, gastric, cervical, pancreatic, and kidney cancers, showed that reintroduction of FHIT resulted in inhibition of in vitro tumor cell growth or of in vivo tumorigenicity in 17 (57%) of 30 cell line experiments. Model systems for human preventive cancer therapy suggested that oral introduction of viral vector-mediated FHIT into Fhit-deficient mice may prevent carcinogen-induced tumor development in some cases. CONCLUSION: These findings show that FHIT gene therapy may potentially be clinically useful for treatment of cancer and also prevention of carcinogen-induced tumor development, suggesting a rationale for further research involving FHIT introduction.     

Family Belongingness Attenuates Entrapment and Buffers Its Association with Suicidal Ideation in a Sample of Dutch Sexual Minority Emerging Adults

Sexual minority emerging adults are more likely to engage in suicidal ideation than their heterosexual counterparts. Experiences of homophobic violence are associated with suicidal ideation. Yet, the specific mechanisms linking homophobic violence to suicidal ideation remain unclear. Entrapment and social belongingness were tested to determine their relevance for understanding the link between homophobic violence and suicidal ideation. A sample of sexual minority Dutch emerging adults (N?=?675; ages 18–29, M?=?21.93 years, SD?=?3.20) were recruited through online platforms and flyers. Homophobic violence was expected to be positively associated with suicidal ideation and entrapment. The association between homophobic violence and suicidal ideation was expected to be indirectly linked through entrapment. We explored whether various sources of social belongingness moderated the path between entrapment and suicidal ideation and whether those sources of social belongingness moderated the indirect effect of homophobic violence on suicidal ideation through entrapment. Results showed that homophobic violence and entrapment were positively associated with suicidal ideation and that family belongingness was negatively associated with suicidal ideation. Homophobic violence and suicidal ideation were not indirectly linked through entrapment. The interaction effect between entrapment and family belongingness was significant, suggesting that, on average, the effect of entrapment on suicidal ideation decreased when family belongingness was high. These results suggest that family belongingness may reduce the association between entrapment and suicidal ideation while adjusting for homophonic violence. Reducing entrapment and improving family belongingness may be useful targets for programs aimed at preventing suicidal ideation among sexual minority emerging adults.

     

The origin of human B and T cells from multipotent stem cells: a study of the Tn syndrome

The Tn (or polyagglutinability) syndrome corresponds to a human nonmalignant acquired condition which results from a somatic mutation occurring at the level of bone marrow stem cells. This model offers therefore a unique opportunity to study the contribution of multipotential stem cells to the maintenance of cells from the lymphoid lineage. We found that the Tn mutation is expressed by both myeloid and lymphoid mature blood cells. Whereas a large proportion of surface IgM-bearing B cells carry the Tn mutation, only a small percentage of T cells and IgA- or IgG-bearing B cells are defective, showing that under physiological conditions the penetration of stem cells into the various myeloid and lymphoid compartments is variable.     

HIV-1感染者外周血单个核细胞缺损病毒基因的研究

目的:研究HIV-1感染者缺损HIV-1 DNA的特性.方法:用长片段PCR法(LD-PCR)研究分析HIV-1感染者外周血单个核细胞(peripheral blood mononuclear, PBMCs)和体外培养感染淋巴细胞中HIV-1基因特征,使用位于HIV-1 DNA链两端的LTR(U5)、LTR(R)为引物,插入有全长HIV-1基因片段的大肠杆菌质粒PNL4-3等为标准对照,并对部分标本克隆测序.结果:经扩增9.1 kb是LD-PCR的主要产物,但在10例HIV-1感染者中有9例PBMCs检测出大小不一、范围较广的缺失HIV-1基因片段,经用基因探针杂交,发现近HIV-1基因中心部位缺失频率增加,缺失结合点常存在3～4个核苷酸短片段直接重复,体外培养中HIV-1基因缺损量减少,完整和缺失基因的存在与培养中病毒分离的时间密切相关.结论:HIV-1感染者PBMCs中存在大量HIV-1基因重组和缺损片段.