The characterization of a subgenomic RNA and in vitro translation products of oat chlorotic stunt virus

Apoptosis has classically been viewed as a process not involving mitochondria, whereas the implication of mitochondrial dysfunction in necrosis has been recognized for several decades. Recently, it has become clear that apoptosis implies a disruption of mitochondrial membrane intregrity that is decisive for the cell death process. Cytofluorometric methods assessing the mitochondrial membrane function and structure can be employed to demonstrate that, at least in most models of apoptosis, mitochondrial changes precede caspase and nuclease activation. Moreover, pharmacological and genetic experiments suggest that the loss of mitochondrial membrane integrity is a critical event of the apoptotic process, beyond or at the point of no return of programmed cell death. Inhibitors of the mitochondrial megachannel (= permeability transition pore) can prevent both the mitochondrial and the post-mitochondrial manifestations of apoptosis.     

Pharmacotherapeutic compass 1998

The Central Medical Pharmaceutical Committee of the Health Insurance Council informs the medical profession annually about the effects of drugs through the Pharmacotherapeutical Compass. The 1998 edition now contains a chapter on pharmacokinetics as well. Compared with previous editions the main alterations of the contents concern an introduction and advice on the antidepressants, two protocols with respect to the medical treatment of patients suffering from epilepsy, advice with respect to oral drugs for the treatment of inflammatory bowel disease, an introduction and advice regarding the treatment of allergic rhinitis, the treatment of patients suffering from AIDS with antiretroviral drugs, the treatment of genital herpes, the taking of insulin lispro by patients with diabetes and the taking of bisphosphonates to prevent or to treat osteoporosis. Two corrections to the 1998 edition are given.     

Synergistic anticancer effects of ganciclovir/thymidine kinase and 5-fluorocytosine/cytosine deaminase gene therapies

BACKGROUND: A bacterial enzyme, Escherichia coli cytosine deaminase, which converts the prodrug 5-fluorocytosine into the toxic drug 5-fluorouracil, and a viral enzyme, herpes simplex virus thymidine kinase, which converts ganciclovir from an inactive prodrug to a cytotoxic agent by phosphorylation, are being actively investigated for use in gene therapy for cancer. The purpose of this study was to determine whether combining these prodrug-activating gene therapies might result in enhanced anticancer effects. METHODS: Rat 9L gliosarcoma cells were transfected with plasmids containing the E. coli cytosine deaminase gene (9L/CD cells), with plasmids containing the herpes simplex virus thymidine kinase gene (9L/TK cells), or with both expression plasmids (9L/CD-TK cells). The drug sensitivities of the cell lines were evaluated; in addition, the sensitivities of 9L and 9L/CD-TK cells mixed in varied proportions were measured. The effects of prodrug treatment on 9L/CD-TK tumor growth (i.e., size and volume) in nude mice were monitored. The isobologram method of Loewe and the multiple drug-effect analysis method of Chou-Talalay were used to measure the interaction between the two prodrug-activating gene therapies. To elucidate the mechanism of interaction, the phosphorylation of ganciclovir in 9L/CD-TK cells after varying prodrug treatments was studied. RESULTS AND CONCLUSIONS: The presence of transfected cytosine deaminase and thymidine kinase genes in 9L gliosarcoma cells reduced cell survival, both in vitro and in vivo, following treatment with the relevant prodrugs; the effects of the two components appeared to be synergistic and related mechanistically to the enhancement of ganciclovir phosphorylation by thymidine kinase following 5-fluorouracil treatment.     

Incomplete ossification of the tarsal bones in foals: 22 cases (1988-1996)

OBJECTIVE: To determine outcome for foals with incomplete ossification of the tarsal bones and to determine whether clinical and radiographic abnormalities at the time of initial examination were associated with outcome. DESIGN: Retrospective study. ANIMALS: 22 foals. PROCEDURE: Information on signalment, history, owner's initial complaint, clinical findings, whether tarsus valgus was evident, and radiographic abnormalities was obtained from medical records. Radiographic lesions were classified as type I (i.e., incomplete ossification with < 30% collapse of the affected bones) or type II (incomplete ossification with > 30% collapse and pinching or fragmentation of the affected bones). Follow-up information was obtained via telephone conversations with owners. RESULTS: Foals were between 1 day and 10 months old when first examined. Eleven were premature (i.e., < 320 days of gestation) or were twins. Sixteen had tarsus valgus. Severity of radiographic lesions was associated with outcome; 4 of 6 foals with type-I incomplete ossification of the tarsal bones performed as intended, but only 3 of 16 foals with type-II incomplete ossification of the tarsal bones performed as intended. CLINICAL IMPLICATIONS: For foals with incomplete ossification of the tarsal bones, severity of the radiographic lesions was associated with outcome. Foals with type-II incomplete ossification of the tarsal bones have a guarded prognosis for athletic soundness.     

Synthesis and biological activity of novel thiazolidinediones

Novel compounds having a dual pharmacophore were synthesised and evaluated for their insulin sensitiser and anti-inflammatory properties in different animal models.     

Glutathione and catalase provide overlapping defenses for protection against hydrogen peroxide in the yeast Saccharomyces cerevisiae

Glutathione (GSH) is an abundant and ubiquitous low-molecular-weight thiol which has proposed roles in many cellular processes including protection against the deleterious effects of reactive oxygen species. Our experiments have addressed the role of GSH in protection against hydrogen peroxide in the yeast Saccharomyces cerevisiae, and have shown that GSH and catalase provide overlapping defense systems. GSH appears to be the primary antioxidant for protection against hydrogen peroxide since mutants lacking GSH (gsh1) or glutathione reductase (glr1) are sensitive, whereas, strains lacking catalase A (cta1) or catalase T (ctt1) are unaffected in resistance to this oxidant. Furthermore, following treatment with hydrogen peroxide, the levels of oxidized, protein-bound and extracellular GSH were all increased at the expense of intracellular GSH. However, there are two lines of evidence that indicate catalases are required in the absence of GSH; firstly, strains that lack both catalase A and T accumulate increased levels of oxidized glutathione following treatment with hydrogen peroxide; and secondly, deletion of catalase genes exacerbates the hydrogen peroxide sensitivity of glr1 and gsh1 mutants.     

Heterogeneity of rheumatoid arthritis: from phenotypes to genotypes

Rheumatoid arthritis (RA) is now recognized as a multigene disorder with a number of genetic polymorphisms contributing to disease pathogenesis. Here, we propose that the diagnostic category of RA includes multiple subtypes of disease and that the different phenotypes of RA correlate to different genotypes. Support for this concept has come from a reappraisal of the clinical heterogeneity of RA and the observation that HLA-DRB1 polymorphisms are useful in describing genetic heterogeneity of RA phenotypes. A series of HLA-DRB1 genes has been identified as RA associated, and in recent years emphasis has been put on the sequence similarities of these alleles. An alternative view focuses on the amino acid variations found in RA-associated HLA-DRB1 alleles with different alleles being enriched in distinct subtypes of RA. Rheumatoid factor-positive destructive joint disease is predominantly associated with the HLA-DRB1*0401 allele, while HLA-DRB1*0404 and B1*0101 predispose for milder and often seronegative disease. Expression of disease-associated alleles on both haplotypes carries a high risk for extra-articular manifestations. In particular, patients homozygous for HLA-DRB1*0401 frequently develop rheumatoid vasculities on follow-up. Besides HLA gene polymorphisms, abnormalities in the generation and function of CD4 T cells and in inflammatory pathways established in synovial lesions can be used to dissect patient subsets with different variants of RA. Emergence of CD28-deficient CD4 T cells identifies RA patients with extra-articular manifestations. These cells undergo clonal expansion in vivo, produce high amounts of IFN-gamma, and exhibit autoreactivity. Concordance of monozygotic twins for the expression of CD4+ CD28- T cells suggests a role for genetic factors in the generation of these unusual T cells. Evidence for heterogeneity of the synovial component of RA comes from studies describing three distinct patterns of lymphoid organization in the synovium. Based upon the topography of tissue-infiltrating mononuclear cells, diffuse, follicular, and granulomatous variants of rheumatoid synovitis can be distinguished. Each pattern of lymphoid organization correlates with a unique profile of tissue cytokines, demonstrating that several pathways of immune deviation modulate disease expression in RA. A dissection of RA variants would have major implications on how the disease is studied, treated, and managed. Identifying combinations of RA risk genes that correlate with disease variants could, therefore, become an important diagnostic tool.