Respiration and ROS production in brain and spinal cord mitochondria of transgenic rats with mutant G93a Cu/Zn-superoxide dismutase gene

Mitochondrial dysfunction is involved in the pathogenesis of motor neuron degeneration in the G93A mutant transgenic (tgmSOD1) animal model of ALS. However, it is unknown whether mitochondriopathy is a primary or secondary event. We isolated brain (BM) and spinal cord (SCM) mitochondria from 2 month old presymptomatic tgmSOD1 rats and studied respiration and generation of reactive oxygen species (ROS) using a new metabolic paradigm (Panov et al., Am. J. Physiol., Regul. Integr. Comp. Physiol., 2011). The yields of BM and SCM from tgmSOD1 rats were 27% and 58% lower than normal rats (WT). The rates of the State 3 and State 3U respiration of tgBM and tgSCM were normal with glutamate+pyruvate+malate as substrates but were inhibited with pyruvate+malate in tgBM and glutamate+malate in tgSCM. In tgSCM the State 4 respiration with all substrates was significantly (1.5-2 fold) increased as compared with WT-SCM. Western blot analysis showed that tgSCM had lower contents of complexes III (-60%) and IV (-35%), and the presence of mutated SOD1 protein in both tgBM and tgSCM. With glutamate+pyruvate+malate or succinate+glutamate+pyruvate+malate as substrates, tgBM and tgSCM generated 5-7 fold more ROS than normal mitochondria, and tgSCM generated two times more ROS than tgBM. We show that the major damaging ROS species in tgmSOD1 animals is H(2)O(2). It is known that mutated SOD1, damaged by H(2)O(2), associates with mitochondria, and we suggest that this further increases production of H(2)O(2). We also show that the total tissue calcium content remained normal in the brain but was diminished by 26% in the spinal cord of presymptomatic tgmSOD1 rats. CONCLUSION: In tgSCM abnormally high rates of ROS generation, associated with reverse electron transport, result in accelerated mitochondriopathy, and the Ca(2+)-dependent excitotoxic death of motor neurons. Thus mitochondrial dysfunction is a key early element in pathogenesis of motor neuron degeneration in tgmSOD1 rats.     

Health-related quality of life in patients with chronic hepatitis C and advanced fibrosis

BACKGROUND/AIMS: Although the antiviral and histological benefits of peginterferon/ribavirin therapy are well established, the effects on health-related quality of life (HRQOL) and sexual health are less certain. This study assessed HRQOL and sexual health in patients with advanced fibrosis or cirrhosis in the HALT-C Trial. METHODS: Subjects completed SF-36 and sexual health questionnaires prior to and after 24 weeks of peginterferon/ribavirin therapy (n=1144). Three hundred and seventy-three (33%) subjects were HCV RNA negative at week 20 and continued therapy through week 48; 258 were seen at week 72. One hundred and eighty achieved sustained virological responses (SVR) and 78 relapsed. RESULTS: At baseline, patients had poorer scores for all eight SF-36 domains compared to healthy controls. Patients with cirrhosis had lower HRQOL scores than those with bridging fibrosis, as did patients with higher depression scores. SVR patients had significant improvements in seven domains, whereas relapsers had significant worsening in one domain. Sexual scores improved in SVR patients and decreased in relapsers (p=0.03). In multivariate analyses, improvements in HRQOL and sexual scores were significantly associated with SVR but were less striking in patients with lower depression scores. CONCLUSIONS: Achievement of SVR after peginterferon/ribavirin therapy improves HRQOL and sexual health in chronic hepatitis C patients with advanced fibrosis or cirrhosis.     

Cytochrome P450 of small intestinal epithelial cells. Immunochemical characterization of the increase in cytochrome P450 caused by phenobarbital

We have studied total cytochrome P450 and the major form of cytochrome P450 increased by phenobarbital in small intestinal epithelial cells and livers of male Sprague-Dawley rats. Using an improved method for preparing microsomes from intestinal epithelial cells, we find that concentrations of total cytochrome P450 in intestinal cell microsomes are 10% of those in liver microsomes, and that this percentage is unchanged after phenobarbital treatment. In untreated rats, less than 5% of total cytochrome P450 of liver or intestinal epithelium is the form induced by phenobarbital, as measured by rocket immunoelectrophoresis. In phenobarbital-treated rats, the major phenobarbital-induced form accounts for approximately 50% of the total in both organs. In the small intestine of phenobarbital-treated rats, the concentrations of total cytochrome P450 and of the major phenobarbital-induced form increase concurrently as epithelial cells mature from crypt to upper villus. Concentrations of total cytochrome P450 and of the major phenobarbital-induced form in the proximal two-thirds of the rat small intestine are twofold higher than in the distal third. Immunoblotting performed with a monoclonal antibody to the major phenobarbital-induced form of cytochrome P450 from rat liver revealed a subtle difference between this form in liver and intestine.     

Four-Hour Measurement of Urinary Iron Excretion after Deferoxine Treatment: A Rapid, Simple Method for Study of Iron Excretion

In a group of 56 patients being evaluated for iron storage disease, all of whom underwent liver biopsy with quantitative measurement of liver iron concentration, urinary excretion of iron was measured following intramuscular injection of deferoxamine (10 mg/kg body weight). Urine was collected in two portions, 0-4 h and 4-24 h after deferoxamine administration. Iron excretion in the first 4 h was closely correlated to that over the entire 24-h period (r = 0.88, p less than 0.0001, 95% confidence interval = 0.80-0.93), indicating that the 4-h deferoxamine urinary excretion test can be adapted readily to an outpatient clinical setting, helping to insure complete and accurate urine collections. Correlation of 0- to 4-h urinary iron excretion and quantitative liver iron (r = 0.335), although higher than for the full 24 h (r = 0.192), was not sufficient to accurately predict hepatic iron concentration in the individual patient.