Tomato: a crop species amenable to improvement by cellular and molecular methods

Tomato is a crop plant with a relatively small DNA content per haploid genome and a well developed genetics. Plant regeneration from explants and protoplasts is feasable which led to the development of efficient transformation procedures. In view of the current data, the isolation of useful mutants at the cellular level probably will be of limited value in the genetic improvement of tomato. Protoplast fusion may lead to novel combinations of organelle and nuclear DNA (cybrids), whereas this technique also provides a means of introducing genetic information from alien species into tomato. Important developments have come from molecular approaches. Following the construction of an RFLP map, these RFLP markers can be used in tomato to tag quantitative traits bred in from related species. Both RFLP's and transposons are in the process of being used to clone desired genes for which no gene products are known. Cloned genes can be introduced and potentially improve specific properties of tomato especially those controlled by single genes. Recent results suggest that, in principle, phenotypic mutants can be created for cloned and characterized genes and will prove their value in further improving the cultivated tomato.

Epstein-Barr virus: clinical and epidemiological revisits and genetic basis of oncogenesis

Epstein-Barr virus (EBV) is classified as a member in the order herpesvirales, family herpesviridae, subfamily gammaherpesvirinae and the genus lymphocytovirus. The virus is an exclusively human pathogen and thus also termed as human herpesvirus 4 (HHV4). It was the first oncogenic virus recognized and has been incriminated in the causation of tumors of both lymphatic and epithelial nature. It was reported in some previous studies that 95% of the population worldwide are serologically positive to the virus. Clinically, EBV primary infection is almost silent, persisting as a life-long asymptomatic latent infection in B cells although it may be responsible for a transient clinical syndrome called infectious mononucleosis. Following reactivation of the virus from latency due to immunocompromised status, EBV was found to be associated with several tumors. EBV linked to oncogenesis as detected in lymphoid tumors such as Burkitt's lymphoma (BL), Hodgkin's disease (HD), post-transplant lymphoproliferative disorders (PTLD) and T-cell lymphomas (e.g. Peripheral T-cell lymphomas; PTCL and Anaplastic large cell lymphomas; ALCL). It is also linked to epithelial tumors such as nasopharyngeal carcinoma (NPC), gastric carcinomas and oral hairy leukoplakia (OHL). In vitro, EBV many studies have demonstrated its ability to transform B cells into lymphoblastoid cell lines (LCLs). Despite these malignancies showing different clinical and epidemiological patterns when studied, genetic studies have suggested that these EBV- associated transformations were characterized generally by low level of virus gene expression with only the latent virus proteins (LVPs) upregulated in both tumors and LCLs. In this review, we summarize some clinical and epidemiological features of EBV- associated tumors. We also discuss how EBV latent genes may lead to oncogenesis in the different clinical malignancie

Intestinal IFN-γ–producing type 1 regulatory T cells coexpress CCR5 and programmed cell death protein 1 and downregulate IL-10 in the inflamed guts of patients with inflammatory bowel disease

BACKGROUND: IL-10 is an anti-inflammatory cytokine required for intestinal immune homeostasis. It mediates suppression of T-cell responses by type 1 regulatory T (TR1) cells but is also produced by CD25+ regulatory T (Treg) cells. OBJECTIVE: We aimed to identify and characterize human intestinal TR1 cells and to investigate whether they are a relevant cellular source of IL-10 in patients with inflammatory bowel diseases (IBDs). METHODS: CD4+ T cells isolated from the intestinal lamina propria of human subjects and mice were analyzed for phenotype, cytokine production, and suppressive capacities. Intracellular IL-10 expression by CD4+ T-cell subsets in the inflamed guts of patients with IBD (Crohn disease or ulcerative colitis) was compared with that in cells from noninflamed control subjects. Finally, the effects of proinflammatory cytokines on T-cell IL-10 expression were analyzed, and IL-1\u3b2 and IL-23 responsiveness was assessed. RESULTS: Intestinal TR1 cells could be identified by coexpression of CCR5 and programmed cell death protein 1 (PD-1) in human subjects and mice. CCR5+PD-1+ TR1 cells expressed IFN-\u3b3 and efficiently suppressed T-cell proliferation and transfer colitis. Intestinal IFN-\u3b3+ TR1 cells, but not IL-7 receptor-positive TH cells or CD25+ Treg cells, showed lower IL-10 expression in patients with IBDs. TR1 cells were responsive to IL-23, and IFN-\u3b3+ TR1 cells downregulated IL-10 with IL-1\u3b2 and IL-23. Conversely, CD25+ Treg cells expressed higher levels of IL-1 receptor but showed stable IL-10 expression. CONCLUSIONS: We provide the first ex vivo characterization of human intestinal TR1 cells. Selective downregulation of IL-10 by IFN-\u3b3+ TR1 cells in response to proinflammatory cytokines is likely to drive excessive intestinal inflammation in patients with IBDs

Coping, social support and quality of life over time after myocardial infarction

Aim. This paper describes gender differences in perceived coping, social support and quality of life 1, 4 and 12 months after myocardial infarction.Background. There is a shortage of studies with a longitudinal research design investigating coping, social support and quality of life in women and men after myocardial infarction.Methods. A longitudinal, descriptive and comparative design was used for the study, which included 74 women and 97 men. At 12 months, 60 women and 88 men remained. Data were collected using the Jalowiec Coping Scale, a social support questionnaire, the SF-36 Health Survey (health-related quality of life) and the Quality of Life Index-Cardiac version (quality of life). The data were collected during the period 1999–2001.Results. No statistically significant changes over time in coping assessments emerged in the study group, except for fatalistic coping, which diminished over time in men. Women used more evasive coping than men at 4 and 12 months. The perceived efficiency in coping with physical aspects of the heart disease increased. More women than men perceived available support from grandchildren and staff of the church. Health-related quality of life increased in women and men in physical functioning, role-physical, vitality, social functioning, and role-emotional scales.Moreover, an improvement in the mental health scale was evident in women and a reduction in pain in men. No statistically significant gender differences were found for quality of life at any point in time.Conclusions. The findings can be used to inform caregivers that optimistic, selfreliant and confrontational coping were the most frequently used by both women and men over the first year after myocardial infarction, and that confrontational coping has been shown to have positive outcomes in the longer term. Nurses should tell women about the importance of seeking prompt treatment and discuss health problems with caregivers and significant others. Care planning should include family members and significant others so that they can support and encourage patients to cope with problems in daily life.</p