Three different approaches were used to investigate the role of extracellular phospholipases in the pathogenicity of Candida albicans. First, we compared 11 blood isolates of this yeast with an equal number of commensal strains isolated from the oral cavities of healthy volunteers. Blood isolates produced significantly more extracellular phospholipase activity than the commensal strains did. Second, two clinical isolates of C. albicans that differed in their levels of virulence in a newborn mouse model were compared for their ability to secrete phospholipases. The invasive strain produced significantly more extracellular phospholipase activity than the noninvasive strain did. Third, nine blood isolates were characterized for their phospholipase and proteinase production, germ tube formation, growth, and adherence to and damage of endothelial cells in vitro. These factors were analyzed subsequently to determine whether they predicted mortality in a mouse model of hematogenously disseminated candidiasis. By proportional hazard analysis, the relative risk of death was 5.6-fold higher (95% confidence interval, 1.672 to 18.84 [P < 0.005]) in the mice infected with the higherphospholipase-secreting strains than in the low-phospholipase secretors. None of the other putative virulence factors predicted mortality. Characterization of phospholipases secreted by three of the blood isolates showed that these strains secreted both phospholipase B and lysophospholipase-transacylase activities. These results implicate extracellular phospholipase as a virulence factor in the pathogenesis of hematogenous infections caused by C. albicans.
The Model for End-Stage Liver Disease (MELD) is an important predictor in patients awaiting orthotopic liver transplantation (OLT). However, the model's association with posttransplant patient survival is unclear. We studied 1-year patient survival in 404 adult patients who underwent OLT at the University of California Los Angeles. The hazard rates of patient survival according to the MELD strata and United Network for Organ Sharing (UNOS) statuses were assessed by Proportional Hazard Cox regression analysis. The difference in survival for MELD strata and UNOS status were compared using the Cox model. There was a significant difference in 1-year patient (P ؍ .0006) survival using different MELD strata, whereas there was a trend according to UNOS status (P ؍ .051). Increased rate of death was observed in recipients of OLT with higher MELD scores (> 36, hazard ratio 3.9; 95% CI 1.55, 10.27) and more urgent UNOS status (2A; hazard ratio, 1.99; 95% CI 1.07, 3.7). The MELD stratum is better associated with 1-year patient survival in liver transplant recipients than UNOS statuses.
We have previously shown that α-linolenic acid (ALA), a (n-3) PUFA exerts in vitro antiinflammatory effects in the intestine. In this study, we aimed to evaluate its effect on inflammatory and oxidative stress in a colitis model. Colitis was induced in 2 groups at d 0 by intrarectal injection of 2-4-6-trinitrobenzen sulfonic acid (TNBS), whereas the control group received the vehicle. Rats we fed 450 mg . kg(-1) . d(-1) of ALA (TNBS+ALA) while the other colitic group (TNBS) and the control group were fed an isocaloric corn oil formula for 14 d (from d -7 to d 7). RBC fatty acid composition was assessed. Oxidative stress was studied by measuring urinary 8-isoprostanes (8-IP) and colon glutathione (GSH) concentration and inducible nitric oxide synthase (iNOS) expression. Colitis was assessed histologically, by production of proinflammatory mediators, including cytokines, leukotrienes B(4) (LTB(4)), and cyclooxygenase-2 (COX-2) and by nuclear factor-κB (NF-κB) activation. The ALA-rich diet significantly increased the RBC levels of ALA, eicosapentaenoic acid, and docosapentaenoic acid (n-3) compared with the TNBS group (P < 0.01 for all). The beneficial effect of ALA supplementation on oxidative stress was reflected by lower urinary 8-IP levels (P < 0.05), a normalized colon GSH concentration (P < 0.01), and reduced colon iNOS expression (P < 0.05) compared with the TNBS group. ALA also protected against colon inflammation as assessed by lower tumor necrosis factor-α secretion and mRNA level (P < 0.05), reduced NF-κB activation (P = 0.01), and lower colon lipid mediator concentrations such as LTB(4) and COX-2 (P < 0.05) compared with the TNBS group. These findings show that an ALA-rich formula is beneficial to TNBS-induced colitic rats via inhibition of oxidative and inflammatory stress.
L iver allocation is currently based on the model for end-stage liver disease score (MELD). 1 The transition from using Child-Turcotte-Pugh (CTP) class to the MELD score in liver transplantation was based on studies demonstrating that the MELD score better predicted short survival than did the United Network for Organ Sharing (UNOS) status, which was based on CTP score. 2,3,4 In a recent study of 3437 adults added to the liver transplantation waiting list, the MELD score was found to be a better predictor of short-term survival than CTP scores. 5 The MELD score uses three laboratory parameters-International Normalized Ratio (INR), serum creatinine, and serum bilirubin, 2,3 -to predict shortterm prognoses and thus is believed to be an accurate measure of liver disease severity. Complications such as hepatic encephalopathy and ascites, which are inherent in the CTP score, are not included in the MELD score. 6 These manifestations of decompensated liver disease are subjective and lack strict operational definition, rendering them amenable to diverse interpretation. Moreover, these manifestations have not shown to increase the predictive ability of the MELD score substantially. 4 While previous studies have demonstrated that liver disease severity as assessed by the CTP score is associated with impaired quality of life, 7,8,9,10,11 it is not clear whether the MELD score is also associated with quality of life. Both hepatic encephalopathy and ascites, which can affect quality of life, are not part of the MELD score. Furthermore, the MELD score has not been correlated with the severity of ascites and hepatic encephalopathy. 12 Thus, liver disease severity assessed by the Abbreviations: MELD, model for end-stage liver disease; CTP,
Platelet microbicidal protein (PMP) is released from platelets in response to thrombin stimulation. PMP is known to possess in vitro bactericidal activity against Staphylococcus aureus and viridans group streptococci. To determine whether PMP is active against other intravascular pathogens, we evaluated its potential fungicidal activity against strains of Candida species and Cryptococcus neoformans. Anionic resin adsorption and gel electrophoresis confirmed that the fungicidal activity of PMP resided in a small (approximately 8.5-kDa), cationic protein, identical to previous studies of PMP-induced bacterial killing (M.R. Yeaman, S.M. Puentes, D.C. Norman, and A.S. Bayer, Infect. Immun. 60:1202-1209, 1992). When assayed over a 180-min period in vitro, the susceptibilities of these fungi to PMP varied considerably. Generally, Candida albicans strains (mean survival, 33.5% +/- 6.9% [n = 6]) as well as isolates of Candida glabrata (mean survival, 50.8% +/- 2.9% [n = 2]) were the most susceptible to killing by PMP, while Candida guillermondii and Candida parapsilosis were relatively resistant to PMP-induced killing. Compared with C. albicans, C. neoformans was relatively resistant to the fungicidal activity of PMP, with a mean survival among the isolates studied of 77.4% +/- 12.4% (n = 6). Against C. albicans, PMP-induced fungicidal activity was time dependent (range, 0 to 180 min), PMP concentration dependent (range, 10 to 150 U/ml), and inversely related to the fungal inoculum (range, 5 x 10(3) to 1 x 10(5) CFU/ml). Scanning electron microscopy of PMP-exposed C. albicans and C. neoformans cells revealed extensive surface damage and collapse, suggesting that the site of PMP fungicidal action may directly or indirectly involve the fungal cell envelope.
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