6 research outputs found

    Isolation and Characterization of the Saccharomyces cerevisiae DPP1 Gene Encoding Diacylglycerol Pyrophosphate Phosphatase

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    Diacylglycerol pyrophosphate (DGPP) is involved in a putative novel lipid signaling pathway. DGPP phosphatase (DGPP phosphohydrolase) is a membrane-associated 34-kDa enzyme fromSaccharomyces cerevisiae which catalyzes the dephosphorylation of DGPP to yield phosphatidate (PA) and then catalyzes the dephosphorylation of PA to yield diacylglycerol. Amino acid sequence information derived from DGPP phosphatase was used to identify and isolate the DPP1(diacylglycerol pyrophosphatephosphatase) gene encoding the enzyme. Multicopy plasmids containing the DPP1 gene directed a 10-fold overexpression of DGPP phosphatase activity in S. cerevisiae. The heterologous expression of the S. cerevisiae DPP1 gene in Sf-9 insect cells resulted in a 500-fold overexpression of DGPP phosphatase activity over that expressed in wild-type S. cerevisiae. DGPP phosphatase possesses a Mg2+-independent PA phosphatase activity, and its expression correlated with the overexpression of DGPP phosphatase activity in S. cerevisiae and in insect cells. DGPP phosphatase was predicted to be an integral membrane protein with six transmembrane-spanning domains. The enzyme contains a novel phosphatase sequence motif found in a superfamily of phosphatases. Adpp1Δ mutant was constructed by deletion of the chromosomal copy of the DPP1 gene. The dpp1Δ mutant was viable and did not exhibit any obvious growth defects. The mutant was devoid of DGPP phosphatase activity and accumulated (4-fold) DGPP. Analysis of the mutant showed that the DPP1 gene was not responsible for all of the Mg2+-independent PA phosphatase activity in S. cerevisiae

    Cryptococcosis in Patients With Cirrhosis of the Liver and Posttransplant Outcomes

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    BACKGROUND: The outcomes and optimal management of cirrhotic patients who develop cryptococcosis before transplantation are not fully known. METHODS: We conducted a multicenter study involving consecutive patients with cirrhosis and cryptococcosis between January 2000 and March 2014. Data collected were generated as standard of care. RESULTS: In all, 112 patients were followed until death or up to 9 years. Disseminated disease and fungemia were present in 76.8% (86/112) and 90-day mortality was 57.1% (64/112). Of the 39 patients listed for transplant, 20.5% (8) underwent liver transplantation, including 2 with active but unrecognized disease before transplantation. Median duration of pretransplant antifungal therapy and posttransplant therapy was 43 days (interquartile range, 8-130 days) and 272 days (interquartile range, 180-630 days), respectively. Transplantation was associated with lower mortality (P = 0.002). None of the transplant recipients developed disease progression during the median follow-up of 3.5 years with a survival rate of 87.5%. CONCLUSIONS: Cryptococcosis in patients with cirrhosis has grave prognosis. Our findings suggest that transplantation after recent cryptococcal disease may not be a categorical exclusion and may be cautiously undertaken in liver transplant candidates who are otherwise deemed clinically stable

    Unique characteristics of cryptococcosis identified after death in patients with liver cirrhosis: comparison with concurrent cohort diagnosed antemortem

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    Characteristics of cirrhosis-associated cryptococcosis first diagnosed after death are not fully known. In a multicenter study, data generated as standard of care was systematically collected in 113 consecutive patients with cirrhosis and cryptococcosis followed for 80 patient-years. The diagnosis of cryptococcosis was first established after death in 15.9% (18/113) of the patients. Compared to cases diagnosed while alive, these patients had higher MELD score (33 vs. 22, P = .029) and higher rate of cryptococcemia (75.0% vs. 41.9%, P = .027). Cases diagnosed after death, in comparison to those diagnosed during life were more likely to present with shock (OR 3.42, 95% CI 1.18-9.90, P = .023), require mechanical ventilation at admission (OR 8.5, 95% CI 2.74-26.38, P = .001), less likely to undergo testing for serum cryptococcal antigen (OR 0.07, 95% CI 0.02-0.21, P \u3c .001) and have positive antigen when the test was performed (OR 0.07, 95% CI 0.01-0.60, P = .016). In a subset of cirrhotic patients with advanced liver disease cryptococcosis was first recognized after death. These patients had the characteristics of presenting with fulminant fungemia, were less likely to have positive serum cryptococcal antigen and posed a diagnostic challenge for care providers

    The effect of induction immunosuppression for kidney transplant on the latent HIV reservoir

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    The HIV latent viral reservoir (LVR) remains a major challenge in the effort to find a cure for HIV. There is interest in lymphocyte-depleting agents, used in solid organ and bone marrow transplantation to reduce the LVR. This study evaluated the LVR and T cell receptor repertoire in HIV-infected kidney transplant recipients using intact proviral DNA assay and T cell receptor sequencing in patients receiving lymphocyte-depleting or lymphocyte-nondepleting immunosuppression induction therapy. CD4 + T cells and intact and defective provirus frequencies decreased following lymphocyte-depleting induction therapy but rebounded to near baseline levels within 1 year after induction. In contrast, these biomarkers were relatively stable over time in the lymphocyte-nondepleting group. The lymphocyte-depleting group had early TCRβ repertoire turnover and newly detected and expanded clones compared with the lymphocyte-nondepleting group. No differences were observed in TCRβ clonality and repertoire richness between groups. These findings suggest that, even with significant decreases in the overall size of the circulating LVR, the reservoir can be reconstituted in a relatively short period of time. These results, while from a relatively unique population, suggest that curative strategies aimed at depleting the HIV LVR will need to achieve specific and durable levels of HIV-infected T cell depletion
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