Ischemia-reperfusion model in rat spinal cord: cell viability and apoptosis signaling study

This work aimed at determining the ideal ischemia time in an in vitro ischemia-reperfusion model of spinal cord injury. Rat spinal cord slices were prepared and then exposed or not to oxygen deprivation and low glucose (ODLG) for 30, 45, 60, 75 and 90 minutes. Cell viability was assessed by triphenyltetrazolium (TTC), lactate dehydrogenase (LDH) release, and fluorochrome dyes specific for cell dead (ethidium homodimer) using the apotome system. Glutamate release was enzymatically measured by a fluorescent method. Gene expression of apoptotic factors was assessed by real time RT-PCR. Whereas spinal cord slices exposed to ODLG exhibited mild increase in fluorescence for 30 minutes after the insult, the 45, 60, 75 and 90 minutes caused a 2-fold increase. ODLG exposure for 45, 60, 75 or 90 minutes, glutamate and LDH release were significantly elevated. nNOS mRNA expression was overexpressed for 45 minutes and moderately increased for 60 minutes in ODLG groups. Bax/bcl-xl ratio, caspase 9 and caspase 3 mRNA expressions were significantly increased for 45 minutes of ODLG, but not for 30, 60, 75 and 90 minutes. Results showed that cell viability reduction in the spinal cord was dependent on ischemic time, resulting in glutamate and LDH release. ODLG for 45 minutes was adequate for gene expression evaluation of proteins and proteases involved in apoptosis pathways.     

Mapping Antigenic Motifs in the Trypomastigote Small Surface Antigen from Trypanosoma cruzi

The trypomastigote small surface antigen (TSSA) is a mucin-like molecule from Trypanosoma cruzi, the etiological agent of Chagas disease, which displays amino acid polymorphisms in parasite isolates. TSSA expression is restricted to the surface of infective cell-derived trypomastigotes, where it functions as an adhesin and engages surface receptors on the host cell as a prerequisite for parasite internalization. Previous results have established TSSA-CL, the isoform encoded by the CL Brener clone, as an appealing candidate for use in serology-based diagnostics for Chagas disease. Here, we used a combination of peptide- and recombinant protein-based tools to map the antigenic structure of TSSA-CL at maximal resolution. Our results indicate the presence of different partially overlapping B-cell epitopes clustering in the central portion of TSSA-CL, which contains most of the polymorphisms found in parasite isolates. Based on these results, we assessed the serodiagnostic performance of a 21-amino-acid-long peptide that spans TSSA-CL major antigenic determinants, which was similar to the performance of the previously validated glutathione S-transferase (GST)-TSSA-CL fusion molecule. Furthermore, the tools developed for the antigenic characterization of the TSSA antigen were also used to explore other potential diagnostic applications of the anti-TSSA humoral response in Chagasic patients. Overall, our present results provide additional insights into the antigenic structure of TSSA-CL and support this molecule as an excellent target for molecular intervention in Chagas disease.     

Lung cancer staging: the value of PET depends on the clinical setting

Background

Although positron emission tomography (PET) imaging is widely recommended in the evaluation of patients with lung cancer, randomized controlled trials (RCTs) assessing this have demonstrated inconsistent results. We asked whether differences in the clinical context and endpoints could explain these discrepancies.

Methods

We used realist synthesis methods to analyze how contextual differences among RCTs affected the results. We focused on RCTs to minimize confounding yet permit evaluation of differences by comparing across studies.

Results

This analysis suggests that the impact of PET depends on the clinical setting. PET is of greatest benefit in identifying M1 disease in patients with a high chance of such involvement and when little traditional imaging [e.g., abdominal/pelvis computed tomography (CT) and bone scan] is used. Identification of N2,3 involvement by PET prior to resection is seen primarily when there is at least a moderate probability of such and the rate of invasive staging is high. The rate of N2 disease not identified preoperatively appears to increase if PET is used to avoid invasive mediastinal staging in clinical settings in which the risk of N2,3 involvement is moderately high. There is both a potential benefit in avoiding stage-inappropriate resection as well as a risk of missed (stage-appropriate) resection if PET findings are not evaluated carefully.

Conclusions

A blanket recommendation for PET may be too simplistic without considering nuances of the clinical setting.     

The length of the Staphylococcus aureus protein A polymorphic region regulates inflammation: impact on acute and chronic infection

Staphylococcus aureus protein A (SpA) plays a critical role in the induction of inflammation. This study was aimed to determine whether the number of short sequence repeats (SSRs) present in the polymorphic region modulates the inflammatory response induced by SpA. We demonstrated that there is a dose-response effect in the activation of interferon (IFN)-β signaling in airway epithelial and immune cells, depending on the number of SSRs, which leads to differences in neutrophil recruitment. We also determined that a significant proportion of isolates from patients with chronic infections such as osteomyelitis and cystic fibrosis carry fewer SSRs than do isolates from patients with acute infections or healthy carriers and that there was an inverse correlation between the number of SSRs and the length of disease course. Given the importance of IFN signaling in eradication of S. aureus, loss of SSRs may represent an advantageous mechanism to adapt to and persist in the host.     

Comparison of High Ribavirin Induction Versus Standard Ribavirin Dosing, Plus Peginterferon-α for the Treatment of Chronic Hepatitis C in HIV-Infected Patients: The PERICO Trial

Background.?Ribavirin (RBV) exposure seems to be critical to maximize treatment response in human immunodeficiency virus (HIV)-positive patients with chronic hepatitis C virus (HCV) infection. Methods.?HIV/HCV-coinfected individuals naive to interferon were prospectively randomized to receive peginterferon-α-2a (180?μg/d) plus either RBV standard dosing (1000 or 1200?mg/d if <75 or ≥75?kg, respectively) or RBV induction (2000?mg/d) along with subcutaneous erythropoietin β (450?IU/kg/wk), both during the first 4 weeks, followed by standard RBV dosing until completion of therapy. Early stopping rules at weeks 12 and 24 were applied in patients with suboptimal virological response. Results.?A total of 357 patients received ≥1 dose of the study medication. No differences in main baseline characteristics were found when comparing treatment arms. Sustained virological response (SVR) was attained by 160 (45%) patients, with no significant differences between RBV induction and standard treatment arms (SVR in 72 of 169 patients [43%] vs 88 of 188 [47%], respectively). At week 4, undetectable HCV RNA (29% vs 25%) and mean RBV trough concentration (2.48 vs 2.14?μg/mL) were comparable in both arms, whereas mean hemoglobin decay was less pronounced in the RBV induction plus erythropoietin arm than in the RBV standard dosing arm (-1.7 vs -2.3?mg/dL; P?相似文献