The effect of soy isoflavones on the development of intestinal neoplasia in ApcMin mouse

Large polymeric 3-alkylpyridinium salts have been isolated from the marine sponge Reniera sarai. They are composed of N-butyl(3-butylpyridinium) repeating subunits, polymerized head-to-tail, and exist as a mixture of two main polymers with molecular weights without counterion of about 5520 and 18900. The monomer analogue of the inhibitor, N-butyl-3-butylpyridinium iodide has been synthesized. This molecule shows mixed reversible inhibition of acetylcholinesterase. The polymers also act as acetylcholinesterase inhibitors and show an unusual inhibition pattern. We tentatively describe it as quick initial reversible binding, followed by slow binding or irreversible inhibition of the enzyme. This kinetics suggests that there are several affinity binding sites on the acetylcholinesterase molecule where the polymer can bind. The first binding favors binding to other sites which leads to an apparently irreversibly linked enzyme-inhibitor complex.     

In vitro blood compatibility of surface-modified polyurethanes

Polyurethanes have proven durable materials for the manufacture of flexible trileaflet heart valves, during in vitro tests. The response of two polyurethanes of differing primary structure to parameters of blood compatibility has now been investigated, using an in vitro test cell. Platelet (beta-thromboglobulin) release, complement (C3a) activation, the activation of free plasma and surface-bound factor XII were studied using fresh, human blood (no anticoagulant) or citrated plasma in control and surface-modified polyurethane. Surface modifications were designed to affect material thrombogenicity and included covalent attachment of heparin, taurine, a platelet membrane glycoprotein fragment, polyethylene oxide (PEO), 3-aminopropyltriethoxysilane, and glucose or glucosamine. Unmodified control polyurethanes caused platelet release and complement activation. High molecular weight (2000 D) polyethylene oxide reduced platelet release slightly but only glucose attachment to the surface produced a significant reduction in platelet activation. All modifications reduced C3 activation compared with controls, but the greatest reduction was achieved with polyethylene oxide attachment or glycosylation. Most surface modifications were more activating of factor XII, both in plasma and on the material surfaces, than the control polyurethanes. Heparin and high molecular weight PEO produced the greatest activation of factor XII in the free plasma form, but low molecular weight PEO and glucosamine produced the greatest activation of surface-bound factor XIIa. The least activating surfaces, affecting both free plasma and surface-bound factor XIIa, were those treated with platelet membrane glycoprotein fragment and glucose. PEO surfaces performed relatively well, compared with controls and most surface modifications. The best overall surface, however, was the glucose-modified surface which was least activating considering all parameters of blood compatibility.     

Partial depletion and multiple deletions of muscle mtDNA in familial MNGIE syndrome

OBJECTIVE: To describe the unique combination of partial depletion and multiple deletions of mitochondrial DNA (mtDNA) on muscle DNA analysis of three siblings with mitochondrial neurogastrointestinal encephalomyopathy (MNGIE). BACKGROUND: MNGIE is a relatively homogeneous autosomal recessive disorder characterized by gastrointestinal dysmobility, ophthalmoparesis, peripheral neuropathy, mitochondrial myopathy, and altered white matter signal at brain imaging. Muscle multiple mtDNA deletions have been found in about half of the described cases. METHODS: We studied three affected siblings (two were monozygotic twins) born to nonconsanguineous parents. Muscle mtDNA was investigated by quantitative Southern and Slot blot techniques and by PCR analysis. Morphologic confirmation in the muscle tissue was achieved by using in situ hybridization with a mtDNA probe complementary to an undeleted region and by DNA immunohistochemistry. RESULTS: All three patients showed ragged red (RRF) and cytochrome c oxidase-negative fibers, as well as partial deficiency of complexes I and IV. Southern and Slot blot analyses showed mtDNA depletion in all patients. Multiple mtDNA deletions were also detected by PCR analysis. In situ hybridization demonstrated an overall signal weaker than controls, with a relatively higher signal in RRF. Antibodies against DNA showed a decreased cytoplasmic network. CONCLUSIONS: The muscle histopathology and respiratory chain enzyme defects may be accounted for by the decreased mtDNA amount and by the presence of mtDNA deleted molecules; however, relative levels of mtDNA seem to correlate with life span in these patients. The combination of partial depletion and multiple deletions of mtDNA might indicate the derangement of a common genetic mechanism controlling mtDNA copy number and integrity.     

Disease and sleep satisfaction at age 70

A new arylnaphthalene lignan, 9-(1,3-benzodioxol-5-yl)-4,5,6, 7-tetramethoxynaphtho[2,3-C]furan-1(3H)-one (5-methoxyjusticidin A, 1), was isolated from a Et2O extract of the wood of Protium unifoliolatum. The structure of 1 was determined by both spectroscopic and X-ray crystallographic methods.     

Stimulation of human cytotoxic T cells with HIV-1-derived peptides presented by recombinant HLA-A2 peptide complexes

HLA-A2 heavy chain and beta 2-microglobulin were expressed in Escherichia coli, and refolded in the presence of peptides derived from HIV-1 RT and gag proteins. When recombinant HLA-A2 molecules were attached to cells lacking HLA-A2, the cells became susceptible to lysis by HLA-A2-restricted cytotoxic T lymphocyte (CTL) clones specific for peptides derived from RT and gag proteins. Limiting dilution analyses of peripheral blood mononuclear cells from HIV-1-infected individuals showed that the recombinant HLA-A2 peptide complexes covalently immobilized on microspheres stimulated the development of HLA-A2 peptide-specific CTL. Preformed HLA-peptide complexes may provide an alternative to immunization procedures that depend upon intracellular processing of antigen to elicit T cell responses.     

17Beta-estradiol antagonizes effects of 1alpha,25-dihydroxyvitamin D3 on interleukin-6 production and osteoclast-like cell formation in mouse bone marrow primary cultures

In mouse bone marrow primary cultures, the formation of osteoclast-like, i.e. tartrate-resistant acid phosphatase (TRAP)- and calcitonin receptor-positive multinucleated cells (MNC), when induced by 1alpha,25-dihydroxyvitamin D3 (1alpha,25(OH)2D3), can be suppressed by 17beta-estradiol (17beta-E2), whereas 17alpha-E2 is without any effect. 17beta-E2, above 10(-11) M, significantly reduced 1alpha,25(OH)2D3-mediated TRAP+ MNC formation in cultured bone marrow cells from both female and male mice. The estrogen at 10(-8) M suppressed the peak response to the vitamin D sterol by 50%. 17beta-E2 significantly suppressed basal and 1alpha,25(OH)2D3-stimulated cellular production of interleukin (IL)-6. IL-6 alone, although bone marrow cells in hormone-free culture produced appreciable amounts of the cytokine, did not induce any TRAP+ MNC. Therefore, the changes in IL-6 production induced by the hormones could not be the sole determinant for the extent of TRAP+ MNC formation. However, the stimulatory effect of 1alpha,25(OH)2D3 on osteoclastogenesis nevertheless can be significantly reduced by a neutralizing monoclonal anti-IL-6 antibody. In the presence of 10(-8) M 17beta-E2, the anti-IL-6 monoclonal antibody does not achieve any further suppression of 1alpha,25(OH)2D3-related osteoclast-like cell formation. Our data suggest that induction of osteoclastogenesis by 1alpha,25(OH)2D3 is partially dependent on IL-6 signaling and can be modulated by 17beta-E2 through interference with IL-6 receptor activation, in addition to inhibition of IL-6 production by marrow stromal cells.     

Mutagenesis of retroviral vectors transducing human beta-globin gene and beta-globin locus control region derivatives results in stable transmission of an active transcriptional structure

Retrovirus-mediated gene transfer of the human beta-globin gene into hematopoietic stem cells is an attractive approach to the therapy of human beta-globin gene disorders. However, expression of the transduced beta-globin gene linked to its proximal cis-acting sequences (-0.8 to +0.3 kb from the cap site) is considerably below the level required for a significant therapeutic effect. The discovery of the beta-locus control region (beta-LCR), organized in four major DNase I hypersensitive sites far upstream of the human beta-like globin gene cluster, provided a potential means to achieve a high level of expression of a linked human beta-globin gene, but initial attempts to incorporate beta-LCR derivatives in retroviral vectors resulted in the production of low-titer viruses with multiple rearrangements of the transmitted proviral structures. We now describe how extensive mutagenesis of the transduced beta-globin gene, eliminating a 372 bp intronic segment and multiple reverse polyadenylation and splicing signals, increases viral titer significantly and restores stability of proviral transmission upon infection of cell lines and bone marrow-repopulating cells. These optimized vectors have enabled us to analyze the expression properties of various retrovirally transduced beta-LCR derivatives in dimethylsulfoxide-induced murine erythroleukemia cells and to achieve ratios of human beta-globin/murine beta maj-globin mRNA, on a per gene basis, as high as 80%.