S-nitrosoglutathione reduces oxidative injury and promotes mechanisms of neurorepair following traumatic brain injury in rats

BACKGROUND

Traumatic brain injury (TBI) induces primary and secondary damage in both the endothelium and the brain parenchyma, collectively termed the neurovascular unit. While neurons die quickly by necrosis, a vicious cycle of secondary injury in endothelial cells exacerbates the initial injury in the neurovascular unit following TBI. In activated endothelial cells, excessive superoxide reacts with nitric oxide (NO) to form peroxynitrite. Peroxynitrite has been implicated in blood brain barrier (BBB) leakage, altered metabolic function, and neurobehavioral impairment. S-nitrosoglutathione (GSNO), a nitrosylation-based signaling molecule, was reported not only to reduce brain levels of peroxynitrite and oxidative metabolites but also to improve neurological function in TBI, stroke, and spinal cord injury. Therefore, we investigated whether GSNO promotes the neurorepair process by reducing the levels of peroxynitrite and the degree of oxidative injury.

METHODS

TBI was induced by controlled cortical impact (CCI) in adult male rats. GSNO or 3-Morpholino-sydnonimine (SIN-1) (50 μg/kg body weight) was administered orally two hours following CCI. The same dose was repeated daily until endpoints. GSNO-treated (GSNO group) or SIN-1-treated (SIN-1 group) injured animals were compared with vehicle-treated injured animals (TBI group) and vehicle-treated sham-operated animals (Sham group) in terms of peroxynitrite, NO, glutathione (GSH), lipid peroxidation, blood brain barrier (BBB) leakage, edema, inflammation, tissue structure, axon/myelin integrity, and neurotrophic factors.

RESULTS

SIN-1 treatment of TBI increased whereas GSNO treatment decreased peroxynitrite, lipid peroxides/aldehydes, BBB leakage, inflammation and edema in a short-term treatment (4-48 hours). GSNO also reduced brain infarctions and enhanced the levels of NO and GSH. In a long-term treatment (14 days), GSNO protected axonal integrity, maintained myelin levels, promoted synaptic plasticity, and enhanced the expression of neurotrophic factors.

CONCLUSION

Our findings indicate the participation of peroxynitrite in the pathobiology of TBI. GSNO treatment of TBI not only reduces peroxynitrite but also protects the integrity of the neurovascular unit, indicating that GSNO blunts the deleterious effects of peroxynitrite. A long-term treatment of TBI with the same low dose of GSNO promotes synaptic plasticity and enhances the expression of neurotrophic factors. These results support that GSNO reduces the levels of oxidative metabolites, protects the neurovascular unit, and promotes neurorepair mechanisms in TBI.

Progressive endoplasmic reticulum stress contributes to hepatocarcinogenesis in fatty acyl-CoA oxidase 1-deficient mice

Fatty acyl-coenzyme A oxidase 1 (ACOX1) knockout (ACOX1(-/-)) mice manifest hepatic metabolic derangements that lead to the development of steatohepatitis, hepatocellular regeneration, spontaneous peroxisome proliferation, and hepatocellular carcinomas. Deficiency of ACOX1 results in unmetabolized substrates of this enzyme that function as biological ligands for peroxisome proliferator-activated receptor-α (PPARα) in liver. Here we demonstrate that sustained activation of PPARα in ACOX1(-/-) mouse liver by these ACOX1 substrates results in endoplasmic reticulum (ER) stress. Overexpression of transcriptional regulator p8 and its ER stress-related effectors such as the pseudokinase tribbles homolog 3, activating transcription factor 4, and transcription factor CCAAT/-enhancer-binding protein homologous protein as well as phosphorylation of eukaryotic translation initiation factor 2α, indicate the induction of unfolded protein response signaling in the ACOX1(-/-) mouse liver. We also show here that, in the liver, p8 is a target for all three PPAR isoforms (-α, -β, and -γ), which interact with peroxisome proliferator response elements in p8 promoter. Sustained activation of p8 and unfolded protein response-associated ER stress in ACOX1(-/-) mouse liver contributes to hepatocyte apoptosis and liver cell proliferation culminating in the development of hepatocarcinogenesis. We also demonstrate that human ACOX1 transgene is functional in ACOX1(-/-) mice and effectively prevents metabolic dysfunctions that lead to ER stress and carcinogenic effects. Taken together, our data indicate that progressive PPARα- and p8-mediated ER stress contribute to the hepatocarcinogenesis in ACOX1(-/-) mice.

Prediction of quantitative intrathoracic fluid volume to diagnose pulmonary oedema using LabVIEW

Pulmonary oedema is a life-threatening disease that requires special attention in the area of research and clinical diagnosis. Computer-based techniques are rarely used to quantify the intrathoracic fluid volume (IFV) for diagnostic purposes. This paper discusses a software program developed to detect and diagnose pulmonary oedema using LabVIEW. The software runs on anthropometric dimensions and physiological parameters, mainly transthoracic electrical impedance (TEI). This technique is accurate and faster than existing manual techniques. The LabVIEW software was used to compute the parameters required to quantify IFV. An equation relating per cent control and IFV was obtained. The results of predicted TEI and measured TEI were compared with previously reported data to validate the developed program. It was found that the predicted values of TEI obtained from the computer-based technique were much closer to the measured values of TEI. Six new subjects were enrolled to measure and predict transthoracic impedance and hence to quantify IFV. A similar difference was also observed in the measured and predicted values of TEI for the new subjects.

Smoking among Saudi university students: consumption patterns and risk factors

Tobacco use is increasing among young people, especially in Gulf nations such as Saudi Arabia. The objectives of this study were to estimate the prevalence and behavioural patterns of tobacco use among undergraduate students at King Saud University, Riyadh, Saudi Arabia during the academic year 2008/09 and investigate factors that influenced their tobacco use. A cross-sectional study was done of a representative sample (n = 6793) of the undergraduate student population using a modified version of the global youth tobacco survey questionnaire. The prevalence of smoking was 14.5% among students, 22.2% and 2.2% among fathers and mothers and 43.1% and 14.8% for male and female siblings; 15.0% reported all or most of their friends smoked. The most important independent predictors of smoking were: friends' smoking (some: OR = 6.7 and all: OR = 54.9), sister's smoking (OR = 2.2), mother's smoking (OR = 2.1), single status (OR = 1.7) and age (OR = 1.18).

Fc24-01 - Ego defense mechanisms in pakistani medical students: a cross sectional analysis

Background

Ego defense mechanisms, defined by Freud as unconscious resources used by the ego to reduce conflict between the id and superego, are a reflection of how an individual deals with conflict and stress. Vaillants’ proposed Hierarchy of Defenses states that mature defenses are associated with better adaptive functioning and health, as opposed to immature defense which are correlated negatively with measures of adaptive adult functioning.

Objectives

This study assesses the prevalence of various ego defense mechanisms employed by medical students of Karachi, which is a group with higher stress levels than the general population.

Methods

A questionnaire based cross-sectional study was conducted on 682 students from five major medical colleges of Karachi in November 2006. Ego defense mechanisms were assessed using the Defense Style Questionnaire(DSQ-40) individually and as grouped under Mature, Immature, and Neurotic factors.

Results

Neurotic defenses had a higher mean score(5.62) than Mature(5.60) and Immature(4.78) mechanisms. Immature mechanisms were more commonly employed by males whereas females employed more Neurotic mechanisms than males. Neurotic and Immature defenses were significantly more prevalent in first and second year students. Mature mechanisms were significantly higher in students enrolled in Government colleges than Private institutions (p< 0.05).

Conclusions

Neurotic mechanisms are more commonly encountered than Mature or Immature mechanisms among medical students of Karachi, and this could reflect greater stress levels than the general population. Employment of these mechanisms was associated with female gender, enrollment in a private medical college, and students enrolled in the first 2 years of medical school.

HIV Type 1 Nef is released from infected cells in CD45(+) microvesicles and is present in the plasma of HIV-infected individuals

HIV-1 Nef has been demonstrated to be integral for viral persistence, infectivity, and the acceleration of disease pathogenesis (AIDS) in humans. Nef has also been detected in the plasma of HIV-infected individuals and is released from infected cells. The form in which Nef is released from infected cells is unknown. However, Nef is a myristoylated protein and has been shown to interact with the intracellular vesicular trafficking network. Here we show that Nef is released in CD45-containing microvesicles. This microvesicular Nef (mvNef) is detected in the plasma of HIV-infected individuals at relatively high concentrations (10 ng/ml). It is also present in tissue culture supernatants of Jurkat cells infected with HIV(MN). Interestingly, plasma mvNef levels in HIV(+) patients did not significantly correlate with viral load or CD4 count. Microvesicular Nef levels persisted in the plasma of HIV-infected individuals despite the use of antiretroviral therapy, even in individuals with undetectable viral loads. Using cell lines, we found Nef microvesicles induce apoptosis in Jurkat T-lymphocytes but had no observed effect on the U937 monocytic cell line. Given the large amount of mvNef present in the plasma of HIV-infected individuals, the apoptotic effect of mvNef on T cells, and the observed functions of extracellular soluble Nef in vitro, it seems likely that in vivo mvNef may play a significant role in the pathogenesis of AIDS.

Comparison between ultrasound and plain X-ray in evaluating the cause of shoulder pain

Painful shoulder is a common painful condition among patients. Apart from acute traumatic lesions such as fractures, dislocations, contusions, sprains and ruptured tendons, 85 to 90% of painful shoulders are due to adhesive capsulitis, acute or chronic calcific tendinitis, bursitis, bicipital tendinitis and lesions of the musculotendinous cuff. Arthritis is the cause of less than 5% of painful shoulders. For evaluating conditions of shoulder joint, X-ray has been regarded as only method of choice for long time. Magnetic resonance imaging (MRI) is an alternative procedure but the cost limits its utilization especially in Bangladesh. Ultrasonography is an effective imaging modality in the evaluation of both rotator and non-rotator cuff disorders. Because of low cost and availability, it can be an alternative procedure for the diagnosis of painful shoulder. The present study was conducted to assess ultrasonography as a useful modality in evaluating cases of shoulder pain and to compare the findings with X-ray findings. Thirty two patients with shoulder pain were evaluated by X-ray and Ultrasonography (USG). Clinical diagnosis was done for correlation. To identify the cause of shoulder pain, 100% patients were found normal in plain X-ray. On Ultrasonography (USG) 12.5% patients had displaced long head of biceps, 21.9% had biceps tendinitis, and 3.1% had bursitis. In the assessment of shoulder pathology, USG had a sensitivity of 73.3%, specificity of 88.2%, Positive predictive value (PPV) of 84.6%, Negative predictive value (NPV) of 78.9% and an accuracy of 81.3%. USG is a useful modality for evaluation the shoulder joint in case of painful shoulder even plain X-ray is non conclusive.

Short-term hyperglycaemia causes non-reversible changes in arterial gene expression in a fully 'switchable' in vivo mouse model of diabetes

AIMS/HYPOTHESIS

Irreversible arterial damage due to early effects of hypo- or hyperglycaemia could account for the limited success of glucose-lowering treatments in preventing cardiovascular disease (CVD) events. We hypothesised that even brief hypo- or hyperglycaemia could adversely affect arterial gene expression and that these changes, moreover, might not be fully reversible.

METHODS

By controlled activation of a 'switchable' c-Myc transgene in beta cells, adult pIns-c-MycER(TAM) mice were rendered transiently hypo- and then hyperglycaemic, after which they were allowed to recover for up to 3 months. Immediate and sequential changes in aortic global gene expression from normal glycaemia through hypo- and hyperglycaemia to recovery were assessed.

RESULTS

Gene expression was compared with that of normoglycaemic transgenic and tamoxifen-treated wild-type controls. Overall, expression of 95 genes was significantly affected by moderate hypoglycaemia (glucose down to 2.5 mmol/l), whereas over 769 genes were affected by hyperglycaemia. Genes and pathways activated included several involved in atherogenic processes, such as inflammation and arterial calcification. Although expression of many genes recovered to initial pre-exposure levels when hyperglycaemia was corrected (74.9%), in one in four genes this did not occur. Quantitative reverse transcriptase PCR and immunohistochemistry verified the gene expression patterns of key molecules, as shown by global gene arrays.

CONCLUSIONS/INTERPRETATION

Short-term exposure to hyperglycaemia can cause deleterious and persistent changes in arterial gene expression in vivo. Brief hypoglycaemia also adversely affects gene expression, although less substantially. Together, these results suggest that early correction of hyperglycaemia and avoidance of hypoglycaemia may both be necessary to avoid excess CVD risk in diabetes.

Steady state performance test analysis of actively cooled extractor grids for SST-1 neutral beam injector

Neutral beam injection (NBI) system is a workhorse to heat magnetically confined tokamak fusion plasma. The heart of any NBI system is an ion extractor system. Steady State Superconducting Tokamak-1 (SST-1) needs 0.5 MW of hydrogen beam power at 30 kV to raise the plasma ion temperature to ~1 keV and 1.7 MW of hydrogen beam power at 55 kV for future upgradation. To meet this requirement, an ion extractor system consisting of three actively cooled grids has been designed, fabricated, and its performance test has been done at MARION test stand, IPP, Julich, Germany. During long pulse (14 s) operation, hydrogen ion beam of energy 31 MJ has been extracted at 41 kV. In this paper, we have presented detailed analysis of calorimetric data of actively cooled extractor grids and showed that by monitoring outlet water temperature, grid material temperature can be monitored for safe steady state operation of a NBI system. Steady state operation of NBI is the present day interest of fusion research. In the present experimental case, performance test analysis indicates that the actively cooled grids attain steady state heat removal condition and the grid material temperature rise is ~18°C and saturates after 10 s of beam pulse.

Purification, characterization and toxicity profile of ricin isoforms from castor beans

The castor seed contains the toxin ricin, one of the most poisonous naturally occurring toxins. The whole of the plant is poisonous, however the seeds are considered the major source of ricin. Ricin exists in different forms in beans of different origin. We investigated the presence of ricin in different isoforms and elucidate some of their structural and biological features isolated from the castor seeds. The isoforms were sub fractionated into ricin I, II and III by chromatography. Their molecular weights lie between 60-65 kDa with difference in their relative electrophoretic mobility. An acidic native PAGE of ricin isoforms at pH 2.9 was performed. Ricin I, II and III are highly cytotoxic against Vero cell line with IC(50) values of 60, 30 and 8 ng/ml respectively. Difference in cytotoxicity of isoforms was confirmed through hemagglutination assay, ricin III caused high degree of hemolysis. The preliminary in vivo toxicity studies showed that ricin III is highly toxic. Immunological studies revealed that anti-ricin I and II antibodies are cross reactive with all the ricin variants, whereas the anti-ricin III antibody is highly specific. The present study shows that anti-ricin I and II antibodies can be used for detection of entire ricin isoforms.

Mitochondrial DNA diversity and PCR-based sex determination of Irrawaddy dolphin (Orcaella brevirostris) from Chilika Lagoon, India

Of the only known two Lagoon populations of Irrawaddy dolphins (Orcaella) in the world, one is residing in the Chilika Lagoon in Orissa state, India. In addition to accidental deaths in gill net fishery and mechanized boat operations, there has been exploitation of the species for their oil. Extreme patchy distribution and vulnerability to becoming entangled in fishing gear has made it a focus of conservation concern. Information on genetic diversity of populations has considerable potential for informing conservation plans. The present paper reports the first genetic study of O. brevirostris from Chilika Lagoon based on mtDNA sequencing and PCR-based sex identification from 11 individuals. Control region sequence comparison showed two haplotypes and cytochrome b a single haplotype in the Chilika population of the species. Phylogenetic analysis indicated distinct clades within the Asian samples, with the Indian population showing closest genetic proximity to the haplotypes from Thailand. Sex of the animal was determined by PCR-based method. It is important to continue to examine the population discreteness and genetic variation of Irrawaddy dolphin in Chilika Lagoon vis-à-vis its global geographic distribution for formulating the conservation plans of the species.