2,681 research outputs found

    Electron-impact excitation of X 1Sigma<sub>g</sub><sup>+</sup>(v[double-prime]=0) to the a[double-prime] 1Sigma<sub>g</sub><sup>+</sup>, b 1Piu, c3 1Piu, o3 1Piu, b[prime] 1Sigma<sub>u</sub><sup>+</sup>, c<sub>4</sub><sup>[prime]</sup> 1Sigma<sub>u</sub><sup>+</sup>, G 3Piu, and F 3Piu states of molecular nitrogen

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    Measurements of differential cross sections (DCSs) for electron-impact excitation of the a[double-prime] 1Sigmag+, b 1Piu, c3 1Piu, o3 1Piu, b[prime] 1Sigmau+, c4[prime] 1Sigmau+, G 3Piu, and F 3Piu states in N2 from the X 1Sigmag+(v[double-prime]=0) ground level are presented. The DCSs were obtained from energy-loss spectra in the region of 12 to 13.82 eV measured at incident energies of 17.5, 20, 30, 50, and 100 eV and for scattering angles ranging from 2° to 130°. The analysis of the spectra follows a different algorithm from that employed in a previous study of N2 for the valence states [Khakoo et al. Phys. Rev. A 71, 062703 (2005)], since the 1Piu and 1Sigmau+ states form strongly interacting Rydberg-valence series. The results are compared with existing data

    Long term follow up of HIV-infected patients with tuberculosis treated with 6-month intermittent short course chemotherapy

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    Background . Tuberculosis occurs in 60%–70% of HIVpositive persons in India. The outcome of HIV-positive patients treated with 6-month intermittent short course antituberculosis regimens in India is not well described. Methods . This was a prospective observational feasibility study of 71 patients with HIV and tuberculosis who were treated with category I regimen of the Revised National Tuberculosis Control Programme (ethambutol, isoniazid, rifampicin and pyrazinamide thrice weekly for the initial 2 months followed by rifampicin and isoniazid thrice weekly for the next 4 months). Sputum was examined by smear and culture for Mycobacterium tuberculosis every month up to 24 months. Chest X-ray, CD4 cell count and viral load were done prior to and at the end of treatment. None of the patients received antiretroviral therapy. Results . We present here the treatment response of patients with sputum culture-positive pulmonary tuberculosis to category I regimen. By efficacy analysis, among 43 patients treated with category I regimen, sputum smear conversion was observed in 79% and culture conversion in 82% at the second month. A favourable response was seen in 72% of patients. The mean (SD) CD4% fell from 12.6 (5.9) to 8.9 (4.9) (p<0.001) with no significant change in mean (SD) CD4 cell count (169 [126] to 174 [158]; ns) at the end of treatment. Viral load change from 1.8x105 at baseline to 1.3x105 at the end of treatment was not statistically significant. Thirty-one patients, who completed the full course of treatment, were declared cured and were followed up for 24 months. Twelve had recurrent tuberculosis (39%); 16 of 43 (37%) patients had died by the end of 24 months, twothirds due to causes other than tuberculosis. Conclusion . Though the early bacteriological response to intermittent short course antituberculosis regimen was satisfactory, the overall outcome was adversely affected by the high mortality (during and after completion of treatment) and recurrence rate among HIV-infected patients with tuberculosis. Immune status deteriorated in spite of antituberculosis treatment, highlighting the need for antiretroviral treatment in addition to antituberculosis treatment to improve the long term outcome. The results of this pilot study need to be confirmed by larger studies

    Cultures of caste and rural development in the social network of a south Indian village

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    Cultures of caste in much of rural India have become entangled with institutions of rural development. In community-driven development, emphasis on “local resource persons” and “community spokespersons” has created new opportunities for brokerage and patronage within some villages, which interact with existing forms of authority and community afforded by caste identity and intra-caste headmanship. In this article, we study how these entangled cultures of caste and development translate into social network structures using data on friendship ties from a south Indian village. We find that although caste continues to be important in shaping community structures and leadership in the village’s network, its influence varies across different communities. This fluidity of caste’s influence on community network structures is argued to be the result of multiple distinct yet partially overlapping cultural-political forces, which include sharedness afforded by caste identity and new forms of difference and inequality effected through rural development

    Mycobacteremia in tuberculosis patients with HIV infection

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    Background: Mycobacteremia in HIV positive tuberculosis patients is associated with extra-pulmonary tuberculosis and disseminated tuberculosis. Objective: To study the occurrence of mycobacteremia among HIV-infected patients with tuberculosis (both pulmonary and extra-pulmonary forms) using radiometric BACTEC method. Methods: HIV positive patients admitted to the Government Hospital of Thoracic Medicine with a clinical diagnosis of tuberculosis were screened. HIV serology was reconfirmed using ELISA (two different tests) at Tuberculosis Research Centre. Five ml of venous blood was collected on the day of admission to the ward before start of anti-tuberculosis therapy. Results: Of the 105 patients screened, 85 were were found to be eligible for analysis. Patients were aged between 20-40 years, with a male preponderance (5:1). Pulmonary tuberculosis was the predominant form of tuberculosis (85%), while 15 % had associated extra-pulmonary involvement. Eight-four percent of the patients had CD4 counts of less than 200 cells/mm3, with 42% being below 50 cells/mm3. Four of the 85 patients were blood culture positive; three were identified as M.tuberculosis and one as Mycobacterium phlei. Conclusions: Mycobacteremia was detected in 4% of HIV positive patients with tuberculosis. All of them were immunosuppressed with CD4 counts of <50 cells/m3. More work needs to be done in India to understand the risk factors and outcome of patients with mycobacteremia

    The cytoplasm of living cells: A functional mixture of thousands of components

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    Inside every living cell is the cytoplasm: a fluid mixture of thousands of different macromolecules, predominantly proteins. This mixture is where most of the biochemistry occurs that enables living cells to function, and it is perhaps the most complex liquid on earth. Here we take an inventory of what is actually in this mixture. Recent genome-sequencing work has given us for the first time at least some information on all of these thousands of components. Having done so we consider two physical phenomena in the cytoplasm: diffusion and possible phase separation. Diffusion is slower in the highly crowded cytoplasm than in dilute solution. Reasonable estimates of this slowdown can be obtained and their consequences explored, for example, monomer-dimer equilibria are established approximately twenty times slower than in a dilute solution. Phase separation in all except exceptional cells appears not to be a problem, despite the high density and so strong protein-protein interactions present. We suggest that this may be partially a byproduct of the evolution of other properties, and partially a result of the huge number of components present.Comment: 11 pages, 1 figure, 1 tabl

    Structural basis of the carbohydrate specificities of Jacalin: an X-ray and modeling study

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    The structures of the complexes of tetrameric jacalin with Gal, Me-α-GalNAc, Me-α-T-antigen, GalNAcβ1-3Gal-α-O-Me and Galα1-6Glc (mellibiose) show that the sugar-binding site of jacalin has three components: the primary site, secondary site A, and secondary site B. In these structures and in the two structures reported earlier, Gal or GalNAc occupy the primary site with the anomeric carbon pointing towards secondary site A. The α-substituents, when present, interact, primarily hydrophobically, with secondary site A which has variable geometry. O-H···π and C-H···π hydrogen bonds involving this site also exist. On the other hand, β-substitution leads to severe steric clashes. Therefore, in complexes involving β-linked disaccharides, the reducing sugar binds at the primary site with the non-reducing end located at secondary site B. The interactions at secondary site B are primarily through water bridges. Thus, the nature of the linkage determines the mode of the association of the sugar with jacalin. The interactions observed in the crystal structures and modeling based on them provide a satisfactory qualitative explanation of the available thermodynamic data on jacalin-carbohydrate interactions. They also lead to fresh insights into the nature of the binding of glycoproteins by jacalin

    Prevalence of Underweight, Stunting, and Wasting among Children Infected with Human Immunodeficiency Virus in South India

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    Background. Growth failure is a common feature of children with human immunodeficiency virus (HIV) infection. Malnutrition increases mortality and may impair the response to antiretroviral treatment. Objective. Our objective was to describe the prevalence of stunting, underweight, and wasting in HIV-infected children in south India and to assess the utility of these parameters in predicting immune status. Methodology. In this cross-sectional study, anthropometric measurements and CD4 counts were performed on 231 HIV-infected children. Z scores for height for age, weight for age, and weight for height were correlated with CD4 cell counts and receiver operating characteristic curves plotted. Results. Prevalence of underweight was 63%, stunting 58%, and wasting 16%, respectively. 33–45% of children were moderately or severely malnourished even at CD4 >25%; sensitivity and specificity of stunting or underweight to predict HIV disease severity was low. Conclusions. Undernutrition and stunting are common among HIV-infected children at all stages of the disease in India. Early and aggressive nutritional intervention is required, if long-term outcomes are to be improved

    Sensitivity & specificity of combination testing algorithms for HIV in a tuberculosis clinic

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    Introduction: Co-management of tuberculosis (TB) and HIV is complicated by pharmacologic drug interactions between rifampicin (RMP) and certain classes of antiretroviral agents. The NNRTIs Nevirapine (NVP) or Efavirenz (EFV), used to HIV infection, are known to induce the CYP 450 enzyme system. Thus when RMP is co-administered along with NVP or EFV, the bioavailability of RMP could be lowered leading to drug resistance and treatment failure. Objectives: To study the steady state pharmacokinetics of RMP in HIV and HIV-TB patients receiving antiretroviral regimens containing NVP or EFV respectively. Methods: The study population comprised of HIV and HIV-TB patients undergoing antiretroviral treatment with NVP and EFV containing regimens respectively. These patients were also receiving concomitant RMP. Rifampicin was estimated by HPLC in blood collected at different time points after drug administration. The pharmacokinetic variables of RMP were calculated using WinNonlin software. Results & Conclusions: Co-administration of NVP or EFV did not alter the pharmacokinetics of RMP in HIV and HIV-TB patients, suggesting that the dose of RMP need not be altered during antiretroviral treatment with NVP or EFV

    E2F site activates transcription in fission yeast Schizosaccharomyces pombe and binds to a 30-kDa transcription factor

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    The mammalian transcription factor E2F binds to several cellular proteins including Rb, p107, cyclin A, cyclin E, and p33cdk2 protein kinase in a stage-specific manner during cell cycle. Its recognition sequence, TTTCGCGC, is present in two of the human adenovirus early promoters and in several promoters of cellular genes whose products are implicated in the control of cell proliferation. These observations suggest that E2F may play an important role in cell-cycle regulation and prompted us to ask whether E2F-like activities are present in yeast. We found that the E2F motif can function as an activating sequence in Schizosaccharomyces pombe when cloned upstream of a reporter gene. Consistent with this, the expression of adenovirus E2 promoter in S. pombe was dependent on both E2F motifs of this promoter. A protein, spE2F, that binds to the E2F site was partially purified from S. pombe using DNA-affinity chromatography. The binding specificity of this protein was compared to that of human E2F using a number of mutant E2F sites as competitors. These studies showed that spE2F recognizes a sequence closely related to the E2F site. Ultraviolet cross-linking and Southwestern blot studies indicated that the molecular size of spE2F is 30 kDa. Previous studies have shown that a cis-acting element, ACGCGTNA, also called MluI cell cycle box, or MCB, is critical for the regulated expression of cell cycle related genes both in fission and budding yeast. In S. pombe, the cdc10 gene product binds to this element and controls the cell cycle related genes. Electrophoretic mobility shift assays and molecular size determination studies indicated that spE2F is different from that encoded by cdc10. Thus, our studies suggest that spE2F is a novel transcription factor. We discuss these results in light of recent observations about the periodically expressed genes involved in the cell cycle progression in yeast

    Acetylator status influences bioavailability of isoniazid in patients with advanced HIV disease

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    Patients with advanced HIV disease may exhibit malabsorption of anti-tuberculosis(TB) drugs. We evaluated the effect of isoniazid (INH) acetylator status on the bioavailability of INH in HIV-infected patients with and without tuberculosis, based on urinary excretion of the drug. Estimation of INH in urine collected up to 8 hours after oral administration of 300 mg INH were undertaken in 23 TB, 40 HIV and 26 HIV-TB patients. Determination of acetylator status of all these patients was also carried by differential estimations of INH and acetyl INH in urine collected between 5 and 6 hours after oral administration of 300 mg INH. Both slow and rapid acetylators in HIV and HIV-TB groups had significantly lower concentration of INH in urine compared to TB patients. The percent decrease in urinary excretion of INH was significantly higher in rapid than in slow acetylators, when compared to the corresponding TB patients. Acetylator status has an impact on the bioavailability of INH. Malbsorption in patients with advanced HIV disease may lead to decreased bioavailability of INH, particularly in rapid acetylators. Urinary estimation of INH provides reliable information on the bioavailability of the drug
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