Intrinsic human immunodeficiency virus type 1 resistance of hematopoietic stem cells despite coreceptor expression

Interactions of human immunodeficiency virus type 1 (HIV-1) with hematopoietic stem cells may define restrictions on immune reconstitution following effective antiretroviral therapy and affect stem cell gene therapy strategies for AIDS. In the present study, we demonstrated mRNA and cell surface expression of HIV-1 receptors CD4 and the chemokine receptors CCR-5 and CXCR-4 in fractionated cells representing multiple stages of hematopoietic development. Chemokine receptor function was documented in subsets of cells by calcium flux in response to a cognate ligand. Productive infection by HIV-1 via these receptors was observed with the notable exception of stem cells, in which case the presence of CD4, CXCR-4, and CCR-5, as documented by single-cell analysis for expression and function, was insufficient for infection. Neither productive infection, transgene expression, nor virus entry was detectable following exposure of stem cells to either wild-type HIV-1 or lentivirus constructs pseudotyped in HIV-1 envelopes of macrophage-tropic, T-cell-tropic, or dualtropic specificity. Successful entry into stem cells of a vesicular stomatitis virus G protein-pseudotyped HIV-1 construct demonstrated that the resistance to HIV-1 was mediated at the level of virus-cell membrane fusion and entry. These data define the hematopoietic stem cell as a sanctuary cell which is resistant to HIV-1 infection by a mechanism independent of receptor and coreceptor expression that suggests a novel means of cellular protection from HIV-1.     

Irreversible inactivation of Caldariomyces fumago chloroperoxidase by hydrogen peroxide. A kinetic study in chloride and bromide system

The rate constants for the H2O2-induced irreversible inactivation (kinact) of chloroperoxidase from Caldariomyces fumago evaluated from the analysis of complete kinetic curves of chlorination or bromination of monochlorodimedon were found to follow the rate law kinact = k[H2O2]/(K + [H2O2]) with k = 0.009 > or = 0.002 and 0.0095 > or = 0.010 s-1 and K = (13 > or = 4) x 10(-3) and (9 > or = 2) x 10(-3) M in the presence of 0.01 M chloride and bromide, respectively, at pH 2.75 and 25 degrees C. The data show that chloroperoxidase investigated is more than by a factor of 10 less resistant toward hydrogen peroxide compared to horseradish peroxidase. The possible reason for it and the biotechnological implications are briefly discussed.     

New techniques for guiding catheter management during directional coronary atherectomy

In an uncontrolled retrospective recall study of 57 patients treated with conical crown retained dentures, 60 restorations (37 in the maxillae and 23 in the mandible jaw) with a mean wearing time of 30.1 months (range 4 to 76) were evaluated. Of the 248 abutments, eight (3.2%) had been lost. Clinically healthy mucosa was seen in 35 jaws. The marginal fit of the copings was judged to be good. No caries or new restorations were observed in 44 patients. Thirteen patients had 19 surfaces with new restorations and 20 surfaces with caries lesions. Of these 39 surfaces, 38 were located subgingivally.     

APOE-epsilon 4 in patients with Alzheimer disease and vascular dementia

This study reports seven cases of epulis excised by the CO2 laser without anesthesia. The laser was used in a continuous wave mode at power setting of 2-4 W. All lesions were excised completely, and no patients felt pain during laser irradiation. The operation was successful without using surgical packs, and there was no postoperative discomfort. There has been no evidence of recurrence after operation.     

Hantavirus antigen detection in kidney biopsies from patients with nephropathia epidemica

We investigated the inhibition mechanism of lipid peroxidation by estrogens. Estradiol and 2-hydroxyestradiol showed strong inhibitory activities toward NADPH and ADP-Fe(3+)-dependent lipid peroxidations in the microsomes from rat livers only when the steroids were added to the reaction system before the start of the peroxidation reaction. These steroids also strongly inhibited oxygen uptake only when added before the start of the reaction. These results suggest that estradiol and 2-hydroxyestradiol inhibit the initial stage of microsomal lipid peroxidation. Lipid peroxidation of erythrocyte membranes induced by the systems of xanthine oxidase-hypoxanthine and ascorbate was strongly inhibited by 2-hydroxyestradiol, but not by estradiol. Lipid peroxidation of erythrocyte membranes induced by 2.2'-azobis- (amidinopropane) dihydrochloride was not markedly inhibited by estradiol and 2-hydroxyestradiol, suggesting that the steroids have low reactivity with lipid peroxyl radicals. However, lipid peroxidation induced by t-butyl hydroperoxide-Fe3+ was strongly inhibited only by 2-hydroxyestradiol. It seems that 2-hydroxyestradiol may interact with alkoxyl rather than with peroxyl radicals during lipid peroxidation.     

Changes in the duodenal glands with a modification of the diet (a histochemical study using lectins)

A set of lectins with different carbohydrate specificities were used for a histochemical analysis of the duodenal glands of rats which had different food rations during 3 months. Lectin receptors in glandulocytes of the duodenum had different spectra under different food regimens: protein diets of the animals correlated with the accumulation of glycopolymers in the glandular epithelium with the terminal residues of N-acetyl-D-galactosamine, N-acetyl-D-glucosamine, L-fucose, higher content of cellulose in food was followed by reduction of fucosoglycans in combination with accumulation of mannose-containing glycopolymers. The regular specific features found point to quantitative and qualitative changes to the formed secretion of the duodenal glands under the influence of changing conditions of nutrition.