Radiation-induced red cell damage: role of reactive oxygen species

BACKGROUND: Cellular blood components are irradiated to prevent graft- versus-host disease in transfusion recipients at risk for this syndrome. Because gamma radiation can result in the production of reactive oxygen species, the role of reactive oxygen species was investigated in radiation-induced red cell damage. STUDY DESIGN AND METHODS: Whole blood from normal donors was exposed to various doses of t-butyl hydroperoxide (0-1 mM) and/or to gamma-radiation (0-50 Gy). Oxidative damage was assessed by the extent of lipid peroxidation (measured by thiobarbituric acid-reactive substances [TBARS]) and hemoglobin oxidation. Fresh blood was divided into three parts-one initially irradiated and stored, another stored with portions irradiated weekly, and a third stored without irradiation. TBARS and hemoglobin oxidation were measured weekly. RESULTS: As expected, t- butyl hydroperoxide induced TBARS formation and hemoglobin oxidation in a dose-dependent fashion. The gamma-radiation not only increased hemoglobin oxidation and TBARS formation, but also enhanced the t-butyl hydroperoxide effect on red cells. Red cell storage increased TBARS generation and hemoglobin oxidation in a time-dependent fashion. When radiation was administered either initially or after weekly storage, TBARS production and hemoglobin oxidation were increased over that measured in unirradiated paired controls. CONCLUSION: Gamma radiation at clinically used doses increases lipid peroxidation and hemoglobin oxidation in human red cells. The effect of gamma-radiation is accentuated by blood storage and induces damage independent of time of storage.     

Pre-B cells and other possible precursor lymphoid cell lines derived from patients with X-linked agammaglobulinemia

A group of unique Epstein-Barr virus-containing cell lines was derived from the bone marrow of three patients with X-linked agammaglobulinemia. Efforts to obtain cell lines from the peripheral blood of these patients were uniformly unsuccessful. Immunofluorescence analyses as well as biosynthetic studies with [(35)S]methionine indicated unusual patterns of Ig synthesis in many of these bone marrow derived lines. Seven of the lines were of particular interest in that two produced no Ig of any type; two others showed no Ig by fluorescence but small amounts by [(35)S]methionine labeling; one expressed only cytoplasmic μ chains without any evidence of light chain synthesis, and two produced primarily μ chains with only slight amounts of light chains. One of the lines without membrane or cytoplasmic Ig studied in detail grew like a typical lymphoid line and was carried in intermittent culture over a period of 2 yr without Ig expression. One line grew quite differently and resembled the round cell type described previously, which has been obtained from a variety of sources. The cell line with cytoplasmic μ chains and no light-chain expression had the characteristic properties of pre-B cells. Three normal type Ig-producing cell lines also were obtained from the patients. The accumulated evidence obtained in the present study indicates that these unusual cell lines represent normal precursor cells of the B-cell lineage; these grew out in these cases because of the virtual absence of mature B cells that ordinarily overgrow the culture system. However, the possibility that in certain instances they reflect abnormal Ig synthesis characteristic of the disease has not been ruled out.     

Bioresorbable vascular scaffold to treat in‐stent restenosis: Single‐center experience

Aims

The management of patients with in‐stent restenosis (ISR) is still a major clinical challenge even in the era of drug‐eluting stents (DES). Recent studies have demonstrated acceptable clinical outcomes for the everolimus‐eluting bioresorbable vascular scaffold (BVS) ABSORB? in patients with stable coronary artery disease but data are scarce on its use in patients with ISR. We report the long‐term results of our preliminary experience with this novel approach at our institution.

Methods and Results

We investigated the safety and efficacy of BVS implantation to treat ISR. 34 consecutive patients (37 lesions) underwent PCI for ISR with BVS implantation between May 2013 and June 2015 at our institution and were included in the current analysis. Follow‐up was available in 91.9% of the patients. Mean follow‐up period was 801.9 ± 179 days. One patient had definite scaffold thrombosis (ScT) 2 months after stent implantation which was treated with DES. Five patients (six lesions) experienced target lesion revascularization (TLR). The composite endpoint rate of TLR, ScT, myocardial infarction, and death occured in 6/37 lesions at follow‐up (16.2%).

Conclusions

These real‐world data using BVS in patients with ISR demonstrates that ISR treatment with ABSORB? BVS is feasible but could have slightly higher target lesion failure rates as compared to DES. This proof of concept could be hypothesis‐generating for larger randomized controlled studies.

     

Xenophagy in Helicobacter pylori‐ and Epstein–Barr virus‐induced gastric cancer

Helicobacter pylori and Epstein–Barr virus (EBV) account for roughly 80% and 10%, respectively, of gastric carcinomas worldwide. Autophagy is an evolutionarily conserved and intricately regulated cellular process that involves the sequestration of cytoplasmic proteins and organelles into double‐membrane autophagosomes that eventually fuse with lysosomes for degradation of the engulfed content. Emerging evidence indicates that xenophagy, a form of selective autophagy, plays a crucial role in the pathogenesis of H. pylori‐ and EBV‐induced gastric cancer. Xenophagy specifically recognizes intracellular H. pylori and EBV and physically targets these pathogens to the autophagosomal–lysosomal pathway for degradation. In this connection, H. pylori or EBV‐induced dysregulation of autophagy may be causally linked to gastric tumourigenesis and therefore can be exploited as therapeutic targets. This review will discuss how H. pylori and EBV infection activate autophagy and how these pathogens evade recognition and degradation by the autophagic pathway. Elucidating the molecular aspects of H. pylori‐ and EBV‐induced autophagy will help us better understand the pathogenesis of gastric cancer and promote the development of autophagy modulators as antimicrobial agents. Published by John Wiley & Sons, Ltd     

Mucosal vaccination delays or prevents prion infection via an oral route

In recent years major outbreaks of prion disease linked to oral exposure of the prion agent have occurred in animal and human populations. These disorders are associated with a conformational change of a normal protein, PrP(C) (prion protein cellular), to a toxic and infectious form, PrP(Sc) (prion protein scrapie). None of the prionoses currently have an effective treatment. A limited number of active immunization approaches have been shown to slightly prolong the incubation period of prion infection. Active immunization in wild-type animals is hampered by auto-tolerance to PrP and potential toxicity. Here we report that mucosal vaccination with an attenuated Salmonella vaccine strain expressing the mouse PrP, is effective at overcoming tolerance to PrP and leads to a significant delay or prevention of prion disease in mice later exposed orally to the 139A scrapie strain. This mucosal vaccine induced gut anti-PrP immunoglobulin (Ig)A and systemic anti-PrP IgG. No toxicity was evident with this vaccination approach. This promising finding suggests that mucosal vaccination may be a useful method for overcoming tolerance to PrP and preventing prion infection among animal and potentially human populations at risk.     

Cerebrospinal fluid hepatocyte growth factor level in meningitis

BACKGROUND AND PURPOSE: Hepatocyte growth factor (HGF) is a multifunctional cytokine that has been found to be elevated in tuberculous and bacterial meningitis, but no evaluation has been undertaken of its usefulness in identifying various forms of aseptic meningitis. METHODS: In a retrospective study, the levels of HGF in the cerebrospinal fluid of 65 patients were measured prior to treatment. The association of HGF with non-infectious diseases and clinically or microbiologically proven bacterial, tuberculous, viral, fungal and parasitic meningitis was observed, along with its relation to other parameters of the cerebrospinal fluid. RESULTS: Forty six of the 65 patients (71%) were diagnosed as having meningitis. Cerebospinal fluid HGF level was significantly elevated in patients with meningitis compared with patients with non-infectious diseases (1501 vs 578 pg/mL; Mann-Whitney U test, p=0.001). The highest HGF level was found in bacterial meningitis (2699 pg/mL), followed by tuberculous meningitis (1540 pg/mL), viral meningitis (1431 pg/mL), fungal meningitis (714 pg/mL) and parasitic meningitis (174 pg/mL). There was no association between HGF level and other parameters of the cerebrospinal fluid (Pearson's correlation test). CONCLUSION: Cerebrospinal fluid HGF may offer additional information in the classification of meningitis. This may assist in patient management when no pathogen is cultured from the cerebrospinal fluid and when other parameters of the cerebrospinal fluid demonstrate equivocal results.