The determination of antimicrobial susceptibility of a clinical isolate, especially with increasing resistance, is often crucial for the optimal antimicrobial therapy of infected patients. Nucleic acid-based assays for the detection of resistance may offer advantages over phenotypic assays. Examples are the detection of the methicillin resistance-encoding mecA gene in staphylococci, rifampin resistance in Mycobacterium tuberculosis, and the spread of resistance determinants across the globe. However, molecular assays for the detection of resistance have a number of limitations. New resistance mechanisms may be missed, and in some cases the number of different genes makes generating an assay too costly to compete with phenotypic assays. In addition, proper quality control for molecular assays poses a problem for many laboratories, and this results in questionable results at best. The development of new molecular techniques, e.g., PCR using molecular beacons and DNA chips, expands the possibilities for monitoring resistance. Although molecular techniques for the detection of antimicrobial resistance clearly are winning a place in routine diagnostics, phenotypic assays are still the method of choice for most resistance determinations. In this review, we describe the applications of molecular techniques for the detection of antimicrobial resistance and the current state of the art

To determine the effect of timing of surgical intervention for necrotizing pancreatitis. Design: Retrospective study of 53 patients and a systematic review. Setting: A tertiary referral center. Main Outcome Measure: Mortality. Results: Median timing of the intervention was 28 days. Eighty-three percent of patients had infected necrosis and 55% had preoperative organ failure. The mortality rate was 36%. Sixteen patients were operated on within 14 days of initial admission, 11 patients from day 15 to 29, and 26 patients on day 30 or later. This latter group received preoperative antibiotics for a longer period (PϽ.001), and Candida species and antibiotic-resistant organisms were more often cultured from the pancreatic or peripancreatic necrosis in these patients (P=.02). The 30-day group also had the lowest mortality (8% vs 75% in the 1 to 14-days group and 45% in the 15 to 29days group, PϽ.001); this difference persisted when outcome was stratified for preoperative organ failure. During the second half of the study, necrosectomy was further postponed (43 vs 20 days, P = .06) and mortality decreased (22% vs 47%, P=.09). We also reviewed 11 studies with a total of 1136 patients. Median surgical patient volume was 8.3 patients per year (range, 5.3-15.6), median timing of surgical intervention was 26 days (range, 3-31), and median mortality was 25% (range, 6%-56%). We observed a significant correlation between timing of intervention and mortality (R=−0.603; 95% confidence interval, −2.10 to −0.02; P =.05). Conclusion: Postponing necrosectomy until 30 days after initial hospital admission is associated with decreased mortality, prolonged use of antibiotics, and increased incidence of Candida species and antibioticresistant organisms.

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Background Tumor segmentation of glioma on MRI is a technique to monitor, quantify and report disease progression. Manual MRI segmentation is the gold standard but very labor intensive. At present the quality of this gold standard is not known for different stages of the disease, and prior work has mainly focused on treatment-naive glioblastoma. In this paper we studied the inter-rater agreement of manual MRI segmentation of glioblastoma and WHO grade II-III glioma for novices and experts at three stages of disease. We also studied the impact of inter-observer variation on extent of resection and growth rate. Methods In 20 patients with WHO grade IV glioblastoma and 20 patients with WHO grade II-III glioma (defined as non-glioblastoma) both the enhancing and non-enhancing tumor elements were segmented on MRI, using specialized software, by four novices and four experts before surgery, after surgery and at time of tumor progression. We used the generalized conformity index (GCI) and the intra-class correlation coefficient (ICC) of tumor volume as main outcome measures for inter-rater agreement. Results For glioblastoma, segmentations by experts and novices were comparable. The inter-rater agreement of enhancing tumor elements was excellent before surgery (GCI 0.79, ICC 0.99) poor after surgery (GCI 0.32, ICC 0.92), and good at progression (GCI 0.65, ICC 0.91). For non-glioblastoma, the inter-rater agreement was generally higher between experts than between novices. The inter-rater agreement was excellent between experts before surgery (GCI 0.77, ICC 0.92), was reasonable after surgery (GCI 0.48, ICC 0.84), and good at progression (GCI 0.60, ICC 0.80). The inter-rater agreement was good between novices before surgery (GCI 0.66, ICC 0.73), was poor after surgery (GCI 0.33, ICC 0.55), and poor at progression (GCI 0.36, ICC 0.73). Further analysis showed that the lower inter-rater agreement of segmentation on postoperative MRI could only partly be explained by the smaller volumes and fragmentation of residual tumor. The median interquartile range of extent of resection between raters was 8.3% and of growth rate was 0.22 mm/year. Conclusion Manual tumor segmentations on MRI have reasonable agreement for use in spatial and volumetric analysis. Agreement in spatial overlap is of concern with segmentation after surgery for glioblastoma and with segmentation of non-glioblastoma by non-experts.

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The objective of this study is to investigate the effects of an acute necrotizing pancreatitis (ANP), without biliary obstruction, on the migrating motor complex (MMC), small bowel bacterial overgrowth (SBBO), bacterial translocation (BT) and infection of the pancreas simultaneously. Rats were divided into four groups: mild pancreatitis, control, ANP and sham operated control. Jejunal myoelectrodes were used to measure MMCs. Blood, peritoneal fluid, bile, and abdominal organs were harvested for microbial culturing 72 h after induction of pancreatitis. The splenic portion of the pancreas was taken for histology. During ANP the MMC cycle length was significantly increased from 14.1 +/- 0.2 to 22.4 +/- 1.9 min (P < 0.05). The duodenum of ANP rats was in contrast with the other groups characterized by Enterobacteriacae (> 3 log 10 CFU g-1 in seven of 12 rats, P < 0.05). A positive correlation (r = 0.78, P < 0.01) existed between duodenal Gram-negative and anaerobic flora and the MMC cycle. Correlation between MMC cycle length and BT to the pancreas was positive as well (r = 0.70, P < 0.01). A positive correlation (r = 0.85, P < 0.01) was found between the severity of pancreatitis and duodenal bacterial overgrowth. During ANP without biliary obstruction, the jejunal MMC is disturbed and consequently SBBO occurs. The correlation between the severity of pancreatitis, the disturbance of the MMC and SBBO suggests an important pathophysiological role of the proximal small bowel in the infection of pancreatic necrosis.

The relationship between T cell activation and human immunodeficiency virus type 1 (HIV-1) replication was studied in HIV-infected subjects, 20 with and 10 without anti-HIV treatment. Expression of Ki-67 proliferation-associated antigen was increased in CD4+ and CD8+ T cells and correlated with HLA-DR. In subjects without anti-HIV treatment, the plasma HIV-1 RNA level correlated with HLA-DR in CD4+ T cells, with Ki-67 in CD8+ T cells, and with expression of CD38 in both T cell subsets. A proportion of treated subjects had increased T cell activation despite 4 months of highly active antiretroviral treatment (HAART). In subjects receiving HAART, a high percentage of HLA-DR+ CD4+ T cells was associated with signs of opportunistic infections. This work supports the concept that, in the natural course of HIV-1 infection, HIV replication itself leads to general T cell activation and that opportunistic infections generate additional CD4+ T cell activation and HIV replication.

Atherosclerotic lesions have been reported to contain herpes simplex virus 1 (HSV-1) genomic material. This, and other previous evidence, suggests that latent viral infection may be an atherogenic trigger. Moreover, active HSV-1 lesions manifest marked fibrin deposition in microvessels. In this report we show that very early infection of human endothelial cells with HSV-1 appears to alter surface conformation as detected by merocyanine 540 staining. Concomitantly, the efficiency of prothrombinase complex assembly increases, resulting in a 2-to 3-fold accelerated rate of thrombin generation on the cell surface. Increased thrombin generation is probably doubly procoagulant, since we also demonstrate that thrombin-induced platelet accumulation on HSV-infected endothellum (50.7 ± 9.3%) is increased compared to uninfected endothelium (9.5 ± 2.1%; P < 0.002). Associated with HSV infection, prostacyclin secretion in response to thrombin is diminished by a factor of 20, probably explaining the enhanced platelet attachment. We conclude that HSV infection shifts endothelial cell properties from anticoagulant to procoagulant, both by promoting prothrombinase complex formation and function and by increasing platelet binding, well before cell disruption takes place. Virus-induced changes in the endothellal plasma membrane and diminished prostacyclin secretion are suggested as the pathways for this pathophysiologic mechanism, which may be germane to atherosclerotic thrombosis as well as HSV-mediated tissue necrosis.An intact vascular endothelium is actively antithrombotic. Rather than forming a passive vascular lining, endothelium has a variety of natural anticoagulant properties that are able to exert a dampening effect upon the coagulation cascade (1, 2): heparin-like species, thrombomodulin, plasminogen activator, and prostacyclin are endothelial constituents thought to contribute to vascular thromboresistance. Consequently, a breach of this barrier by mechanical disruption of the endothelial lining with frank endothelial loss and exposure of the subendothelium can lead to massive coagulation activation and platelet adherence. More subtle injury to endothehum that might alter its thromboresistant properties has only recently emerged as a topic of inquiry (3). Theoretically, several different mechanisms may be involved in diminished endothelial thromboresistance: (i) decreased production or exhibition of the above-mentioned antithrombotic factors; (ii) increased production or secretion ofthrombogenic factors such as tissue factor, platelet-activating factor, von Willebrand factor, and plasminogen-activator inhibitor; and (iii) changes in the endothelial cell surface, leading to altered exposure of proteins or procoagulant phospholipids.With regard to mechanism iii, endothelial cell surface alterations can result from viral infection, which readily occurs with several viruses in vitro. Diverse viruses replicate readily in cultured endothelium, including herpesviruses, adenoviruses, and enteroviruses, among others (4,...