The kinetics of sodium channel inactivation in the sensory neurons depends on the type of hydrogen ion buffer

The kinetics of inactivation of TTX-sensitive and TTX-resistant sodium channels in the excitable membrane of rat dorsal root ganglion cells were studied using whole-cell recording technique with the presence of two different pH buffers, Tris and Hepes. It is shown that Tris ions irreversibly interact with inactivation system, accelerating the decaying phase of sodium current. The buffer regulates the gating machinery of two types of the channels. It makes the second order properties more pronounced. On the contrary, the characteristics of inactivation process in Hepes are more close to that we register immediately after the rupture of the cell membrane. We suppose that Hepes buffer is more adequate for investigation of sodium channel inactivation processes.     

In vitro induction of primary DNA double-strand breaks in leukemic and normal blood cells by ultraviolet irradiation

The yield of UV-induced DNA double-strand breaks was studied for white blood cells ("light" fraction) derived from peripheral blood, and from patients with lymphomas, chronic lymphoid leukemia (CLL), and chronic myeloid leukemia (CML). The method employed was constant-field electrophoresis of plug-embedded DNA in agarose gel. Characteristic dose-response curves were obtained for various cell populations. Lymphoid cells, both from healthy subjects and CLL patients, revealed less damage to DNA under UV-irradiation, whereas CML cells were much more affected. Possible interpretation of these results includes species-specific differences in UV-induced DNA damage, as well as sufficient DNA crosslinking, thus interfering with DNA dsbs detection in irradiated cells.     

Acculturation, sexual behavior, and alcohol use among Latinas

We explored the relationship of alcohol use to unsafe sex in Latinas. Telephone interviews were conducted with 523 currently sexually active Latinas aged 18-49 years. Only 7.5% of these women used alcohol half of the time or more prior to sex. "Regular" alcohol users had more sexual partners, but also had more experience with condom use, used condoms with primary partners as frequently as nonusers of alcohol, and used condoms more with secondary partners. While Latinas who use alcohol prior to sex more often have multiple sexual partners, alcohol use does not appear to interfere with condom use.     

Human monocyte binding to fibronectin enhances IFN-gamma-induced early signaling events

Leukocyte integrins are fundamentally important in modulating adhesion to extracellular matrix components and to other cells. This integrin-mediated adhesion controls leukocyte arrest and extravasation during the onset of inflammatory responses. Moreover, integrin-ligand interactions trigger signaling pathways that may influence leukocyte phenotype and function at sites of inflammation. In the current studies, we evaluated the combinatorial effects of monocyte adhesion and IFN-gamma on intracellular signaling pathways. IFN-gamma triggers a well-defined signal transduction pathway, which although not directly stimulated by monocyte adherence to fibronectin or arginine-glycine-aspartate (RGD)-coated substrata, was enhanced significantly in these matrix-adherent cells. Compared with monocytes in suspension or adherent on plastic surfaces, monocytes adherent to fibronectin or RGD exhibited a greater than threefold increase in steady state levels of IFN-gamma-induced mRNA for the high affinity Fc gammaRI receptor. By electrophoretic mobility shift assays, this increase in mRNA was associated with a 5- to 10-fold increase in the STAT1-containing DNA-binding complex that binds to Fc gammaRI promoter elements. Furthermore, the tyrosine phosphorylation of STAT1 and the tyrosine kinases JAK1 and JAK2 was enhanced significantly in RGD-adherent monocytes compared with control cells. These results suggest a novel mechanism by which integrin-mediated cell adhesion can modulate the magnitude of cytokine-induced signal transduction pathways, thereby amplifying cellular events leading to monocyte activation and inflammation.     

Designing the latex test system for express identification of legionella in the external medium and clinical materials

Biopsies and blood of 36 patients with bedsores developing due to spinal cord trauma were studied. Pronounced alterations in the blood content of IgA, IgM, IgG, a significant increase in circulating immune complexes (CIC) content and a decrease of neutrophil leukocyte chemotactic activity were found. The authors conclude that an immune system dysfunction occurs in patients with bedsores as well as secondary immune deficiency and immunoglobulin and CIC deposition in the granulation tissue vessels. Development of chronic vasculitis, obliteration and reduction of vessels, hypoxia and metabolic disturbances in the wound edges, formation of deficient fibroblasts synthesizing collagen type III which does not facilitate skin epithelium maturation, all these changes result in a chronic course of the wound and almost complete lack of healing.     

Efficacy of spray application of chlorinated water in killing pathogenic bacteria on raw apples, tomatoes, and lettuce

Washing whole and cut produce by dipping or submerging in chlorinated water has a sanitizing effect, although reduction in microbial populations is minimal and is usually less than 100-fold. A study was undertaken to evaluate the efficacy of a spray application of chlorine in killing Salmonella, Escherichia coli O157:H7, Listeria monocytogenes, yeasts and molds, and total aerobic mesophilic microorganisms on whole apples, tomatoes, and lettuce leaves. Inoculated produce was treated (sprayed and then soaked) with water (control) or solutions containing 200 or 2,000 ppm of chlorine for 0, 1, 3, 5, or 10 min, rinsed with sterile water, and analyzed for populations (CFU/cm2) of target microorganisms. Compared to the control treatment, further reductions in numbers of pathogens of 0.35 to 2.30 log CFU/cm2 were achieved by treatment with chlorine. Chlorine was generally more effective at 2,000 ppm than at 200 ppm. Inactivation of microorganisms occurred essentially within 1 min after application of chlorine. These reductions are significant relative to populations of pathogenic microorganisms that may be present on produce. Spray application of chlorine to raw produce at food service or household levels may be a suitable, and more convenient, alternative to treatment by dipping or submersion.     

Disruption of a PEX1-PEX6 interaction is the most common cause of the neurologic disorders Zellweger syndrome, neonatal adrenoleukodystrophy, and infantile Refsum disease

Peroxisomal matrix protein import requires the action of two AAA ATPases, PEX1 and PEX6. Mutations in either the PEX1 or PEX6 gene are the most common cause of the lethal neurologic disorders Zellweger syndrome, neonatal adrenoleukodystrophy, and infantile Refsum disease and account for disease in 80% of all such patients. We report here that overexpression of PEX6 can suppress the phenotypes of certain PEX1-deficient cells, that overexpression of PEX1 can suppress the phenotypes of certain PEX6-deficient cells, and that these instances of suppression are allele-specific and require partial activity of the mutated gene. In addition to genetic evidence for interaction between PEX1 and PEX6, we find that the PEX1 and PEX6 proteins interact in the yeast two-hybrid assay and physically associate with one another in vitro. We previously identified a missense mutation in PEX1, G843D, which attenuates PEX1 function and is the most common cause of these diseases, present in one-third of all such patients. The G843D mutation attenuates the interaction between PEX1 and PEX6 in both the two-hybrid system and in vitro and appears to be suppressed by overexpression of PEX6. We conclude that PEX1 and PEX6 form a complex of central importance to peroxisome biogenesis and that mutations affecting this complex constitute the most common cause of the Zellweger syndrome spectrum of diseases.     

Viracept (nelfinavir mesylate, AG1343): a potent, orally bioavailable inhibitor of HIV-1 protease

Using a combination of iterative structure-based design and an analysis of oral pharmacokinetics and antiviral activity, AG1343 (Viracept, nelfinavir mesylate), a nonpeptidic inhibitor of HIV-1 protease, was identified. AG1343 is a potent enzyme inhibitor (Ki = 2 nM) and antiviral agent (HIV-1 ED50 = 14 nM). An X-ray cocrystal structure of the enzyme-AG1343 complex reveals how the novel thiophenyl ether and phenol-amide substituents of the inhibitor interact with the S1 and S2 subsites of HIV-1 protease, respectively. In vivo studies indicate that AG1343 is well absorbed orally in a variety of species and possesses favorable pharmacokinetic properties in humans. AG1343 (Viracept) has recently been approved for marketing for the treatment of AIDS.