Low oxygen tension enhances hepatitis C virus replication.

Low oxygen tension exerts a significant effect on the replication of several DNA and RNA viruses in cultured cells. In vitro propagation of hepatitis C virus (HCV) has thus far been studied under atmospheric oxygen levels despite the fact that the liver tissue microenvironment is hypoxic. In this study, we investigated the efficiency of HCV production in actively dividing or differentiating human hepatoma cells cultured under low or atmospheric oxygen tensions. By using both HCV replicons and infection-based assays, low oxygen was found to enhance HCV RNA replication whereas virus entry and RNA translation were not affected. Hypoxia signaling pathway-focused DNA microarray and real-time quantitative reverse transcription-PCR (qRT-PCR) analyses revealed an upregulation of genes related to hypoxic stress, glycolytic metabolism, cell growth, and proliferation when cells were kept under low (3% [vol/vol]) oxygen tension, likely reflecting cell adaptation to anaerobic conditions. Interestingly, hypoxia-mediated enhancement of HCV replication correlated directly with the increase in anaerobic glycolysis and creatine kinase B (CKB) activity that leads to elevated ATP production. Surprisingly, activation of hypoxia-inducible factor alpha (HIF-α) was not involved in the elevation of HCV replication. Instead, a number of oncogenes known to be associated with glycolysis were upregulated and evidence that these oncogenes contribute to hypoxia-mediated enhancement of HCV replication was obtained. Finally, in liver biopsy specimens of HCV-infected patients, the levels of hypoxia and anaerobic metabolism markers correlated with HCV RNA levels. These results provide new insights into the impact of oxygen tension on the intricate HCV-host cell interaction.

High levels of HCV core+1 antibodies in HCV patients with hepatocellular carcinoma.

The core region of the hepatitis C virus (HCV) genome possesses an overlapping ORF that has been shown to encode a protein, known as the alternate reading frame protein (ARFP), F or core+1. The biological role of this protein remains elusive, as it appears to be non-essential for virus replication. However, a number of independent studies have shown that the ARFP/F/core+1 protein elicits humoral and cellular immune responses in HCV-infected individuals and interacts with important cellular proteins. To assess the significance of the core+1 humoral response in HCV-infected patients, we examined the prevalence of anti-core+1 antibodies in sera from patients with hepatocellular carcinoma (HCC) in comparison with chronically HCV-infected individuals without HCC. We produced two HCV core+1 histidine-tagged recombinant proteins for genotypes 1a (aa 11-160) and 1b (aa 11-144), as well as a non-tagged highly purified recombinant core+1/S protein (aa 85-144) of HCV-1b. Using an in-house ELISA, we tested the prevalence of core+1 antibodies in 45 patients with HCC in comparison with 47 chronically HCV-infected patients without HCC and 77 negative-control sera. More than 50 % of the serum samples from HCC patients reacted with all core+1 antigens, whereas <26 % of the sera from the non-HCC HCV-infected individuals tested positive. No core+1-specific reactivity was detected in any of the control samples. In conclusion, the high occurrence of anti-core+1 antibodies in the serum of HCC patients suggests a role for the ARFP/F/core+1 protein in the pathogenesis of HCC.

Psychogenic status epilepticus in children.

Epilepsy features, psychiatric profile, psychosocial factors, and outcome are described for six children (three males) aged 5-15 years (mean 12.1) with psychogenic status epilepticus (PSE), i.e., prolonged or repetitive psychogenic seizures (PSs), >30 minutes, simulating status epilepticus. They had epilepsy, they were on chronic anticonvulsants (ACVs), and some had other neurological deficits. All received intravenous and/or rectal ACVs prior to suspicion of PSE. PSE was confirmed via video/EEG, demonstrating no epileptogenic activity during alleged seizures. Provocation and placebo therapy techniques were used in two. Psychiatric assessment identified comorbid disorders such as depression, anxiety disorder, obsessive-compulsive disorder, obsessive-compulsive symptoms, and posttraumatic stress disorder. Psychosocial stressors were almost ubiquitous. Psychiatric intervention included psychotherapy, family therapy, and medical treatment in one patient. Outcome was monitored for an average of 3.6 years (3-5 years). PSE did not recur. PSs recurred in three. Psychiatric comorbidity improved in four, who accepted psychiatric intervention and whose epilepsy also improved. In conclusion, the occurrence of PSE in children and adolescents with epilepsy is stressed. Prompt diagnosis was often missed in the acute care setting, and this carries important implications for iatrogenic complications. PSE diagnosis resulted in identification and management of comorbid psychiatric disorders. This was probably important in reducing the predominating anxiety and affective disorders in most patients as well as PSE recurrence. Epilepsy severity and associated deficits were most likely important factors in determining outcome.