NAD(P)H: Quinone Oxidoreductase 1 Deficiency Conjoint with Marginal Vitamin C Deficiency Causes Cigarette Smoke Induced Myelodysplastic Syndromes

BACKGROUND: The etiology of myelodysplastic syndromes (MDS) is largely unknown. Exposure to cigarette smoke (CS) is reported to be associated with MDS risk. There is inconsistent evidence that deficiency of NAD(P)H-quinone: oxidoreductase 1 (NQO1) increases the risk of MDS. Earlier we had shown that CS induces toxicity only in marginal vitamin C-deficient guinea pigs but not in vitamin C-sufficient ones. We therefore considered that NQO1 deficiency along with marginal vitamin C deficiency might produce MDS in CS-exposed guinea pigs. METHODOLOGY AND PRINCIPAL FINDINGS: Here we show that CS exposure for 21 days produces MDS in guinea pigs having deficiency of NQO1 (fed 3 mg dicoumarol/day) conjoint with marginal vitamin C deficiency (fed 0.5 mg vitamin C/day). As evidenced by morphology, histology and cytogenetics, MDS produced in the guinea pigs falls in the category of refractory cytopenia with unilineage dysplasia (RCUD): refractory anemia; refractory thrombocytopenia that is associated with ring sideroblasts, micromegakaryocytes, myeloid hyperplasia and aneuploidy. MDS is accompanied by increased CD34(+) cells and oxidative stress as shown by the formation of protein carbonyls and 8-oxodeoxyguanosine. Apoptosis precedes MDS but disappears later with marked decrease in the p53 protein. MDS produced in the guinea pigs are irreversible. MDS and all the aforesaid pathophysiological events do not occur in vitamin C-sufficient guinea pigs. However, after the onset of MDS vitamin C becomes ineffective. CONCLUSIONS AND SIGNIFICANCE: CS exposure causes MDS in guinea pigs having deficiency of NQO1 conjoint with marginal vitamin C deficiency. The syndromes are not produced in singular deficiency of NQO1 or marginal vitamin C deficiency. Our results suggest that human smokers having NQO1 deficiency combined with marginal vitamin C deficiency are likely to be at high risk for developing MDS and that intake of a moderately large dose of vitamin C would prevent MDS

The Effect of Stimulus Rates in Chirp and Click Evoked Auditory Brainstem Response in Adults with Normal Hearing Sensitivity

Introduction The effects of increasing stimulus repetition rate on the ABR using click stimuli have been investigated in normal and hearing impaired subjects with neurologic abnormality but there is limited study on the effect of stimulus repetition rate on ABR using chirp stimuli. The present study aims to compare the chirp evoked auditory brainstem responses with reference to changes in latency of peaks, interaural latency differences and interwave latency intervals as a function of rate and compare those responses with the  click evoked auditory brainstem responses, in normal hearing subjects. Materials and Methods Total 30 normally hearing adults were considered for this study. All participants were screened for normal hearing sensitivity upto 8 kHz in pure tone audiometry for middle ear pathology and central auditory processing disorder. Four parameters of ABR were considered to assess in this study including absolute latency, interwave latency intervals, latency-rate function and interaural latency. ABR was done based on the protocol of this study. Results Results revealed that there was a significant difference in the absolute latency and interwave intervals when the stimulus repetition rate was increased. Conclusion The latencies of wave III and V increases and waveform morphology changed as the stimulus repetition rate increased above 20/sec. The absolute latency of wave III and V was found to be shorter than clicks and can be used especially in newborn hearing evaluation assuming in shorter time window

Achieving abiotic stress tolerance in plants through antioxidative defense mechanisms

Climate change has increased the overall impact of abiotic stress conditions such as drought, salinity, and extreme temperatures on plants. Abiotic stress adversely affects the growth, development, crop yield, and productivity of plants. When plants are subjected to various environmental stress conditions, the balance between the production of reactive oxygen species and its detoxification through antioxidant mechanisms is disturbed. The extent of disturbance depends on the severity, intensity, and duration of abiotic stress. The equilibrium between the production and elimination of reactive oxygen species is maintained due to both enzymatic and non-enzymatic antioxidative defense mechanisms. Non-enzymatic antioxidants include both lipid-soluble (α-tocopherol and β-carotene) and water-soluble (glutathione, ascorbate, etc.) antioxidants. Ascorbate peroxidase (APX), superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GR) are major enzymatic antioxidants that are essential for ROS homeostasis. In this review, we intend to discuss various antioxidative defense approaches used to improve abiotic stress tolerance in plants and the mechanism of action of the genes or enzymes involved

Viper and Cobra Venom Neutralization by b-Sitosterol and Stigmasterol Isolated from the Root Extract of Pluchea Indica Less. (Asteraceae)

We reported previously that the methanolic root extract of the Indian medicinal plant Pluchea indica Less. (Asteraceae) could neutralize viper venom-induced action [Alam, M.I., Auddy, B., Gomes, A., 1996. Viper venom neutralization by Indian medicinal plant (Hemidesmus indicus and P. indica) root extracts. Phytother. Res. 10, 58–61]. The present study reports the neutralization of viper and cobra venom by b-sitosterol and stigmasterol isolated from the root extract of P. indica Less. (Asteraceae). The active fraction (containing the major compound b-sitosterol and the minor compound stigmasterol) was isolated and purified by silica gel column chromatography and the structure was determined using spectroscopic analysis (EIMS, 1H NMR, 13C NMR). Anti-snake venom activity was studied in experimental animals. The active fraction was found to significantly neutralize viper venom-induced lethal, hemorrhagic, defibrinogenation, edema and PLA2 activity. Cobra venom-induced lethality, cardiotoxicity, neurotoxicity, respiratory changes and PLA2 activity were also antagonized by the active component. It potentiated commercial snake venom antiserum action against venom-induced lethality in male albino mice. The active fraction could antagonize venom-induced changes in lipid peroxidation and superoxide dismutase activity. This study suggests that b-sitosterol and stigmasterol may play an important role, along with antiserum, in neutralizing snake venominduced actions

dGTP-Templated Luminescent Gold Nanocluster-Based Composite Nanoparticles for Cancer Theranostics

dGTP-templated facile synthesis of luminescent gold nanoclusters (Au NCs) in the presence of cisplatin following PEG coating developed spherical composite NPs. The composite NPs delivered cisplatin efficiently into HeLa cells to induce apoptosis-mediated cell death, and simultaneously bioimaged the cellular uptake

Cigarette Smoke induces p-Benzoquinone–Albumin Adduct in Blood Serum:Implications on Structure and Ligand Binding Properties

Earlier we had reported that irrespective of the source cigarette smoke (CS) contains substantial amounts of p-benzosemiquinone, which is readily converted to p-benzoquinone (p-BQ) by disproportionation and oxidation by transition metal containing proteins. Here we show that after CS-exposure, p-BQ-protein adducts are formed in the lungs as well as serum albumin of guinea pigs. We also show that serum of human smokers contains p-BQ-albumin adduct. It is known that human serum albumin (HSA) plays a very important role in binding and transport of a variety of ligands, including fatty acids and drugs. We show in vitro that p-BQ forms covalent adducts with free amino groups of all twenty amino acids as well as �-amino groups of lysine residues of HSA in a concentration dependent manner. When HSA is incubated with p-BQ in the molar ratio of 1:1, the number of p-BQ incorporated is 1. At the molar ratio of 1:60, the number of p-BQ incorporated is 40. The formation of HSA–p-BQ adduct has been demonstrated by absorption spectroscopy, MALDI-MS and MALDI-TOF–TOF-MS analyses. Upon complexation with p-BQ, the secondary structure and conformation of HSA are altered, as evidenced by steady state and timeresolved fluorescence, circular dichroism, 8-anilino-1-napthalenesulfonic acid binding and differential scanning calorimetry. Alteration of the structure and conformation of HSA results in impairment of its ligand binding properties with respect to myristic acid, quercitin and paracetamol. This might be one of the reasons why transport and distribution of lipids and drugs are impaired in smoker

Molecular and Cellular Mechanisms of Cigarette Smoke-Induced Myocardial Injury: Prevention by Vitamin C

<div><h3>Background</h3><p>Cardiovascular disease (CVD) remains one of the major killers in modern society. One strong risk factor of CVD is cigarette smoking that causes myocardial injury and leads to the genesis of pathological cardiovascular events. However, the exact toxic component(s) of cigarette smoke (CS) and its molecular and cellular mechanisms for causing myocardial injury leading to heart damage and its prevention are largely unknown.</p> <h3>Methodology/Principal Findings</h3><p>Using a guinea pig model, here we show that chronic exposure to CS produces myocardial injury that is prevented by vitamin C. Male guinea pigs were fed either vitamin C-deficient (0.5 mg/day) or vitamin C-sufficient (15 mg/day) diet and subjected to CS exposure from 5 Kentucky Research cigarettes (3R4F)/day (6 days/week) in a smoke chamber up to 8 weeks. Pair-fed sham controls were subjected to air exposure instead of CS exposure under similar conditions. Myocardial injury was produced in CS-exposed marginal vitamin C-deficient guinea pigs as evidenced by release of cardiac Troponin-T and I in the serum, oxidative stress, inflammation, apoptosis, thrombosis and collagen deposition in the myocardium. Treatment of rat cardiomyocyte cells (H9c2) <em>in vitro</em> and guinea pigs <em>in vivo</em> with p-benzoquinone (p-BQ) in amounts derived from CS revealed that p-BQ was a major factor responsible for CS-induced myocardial damage. A moderately large dose of vitamin C (15 mg/day) prevented CS/p-BQ-induced myocardial injury. Population based studies indicated that plasma vitamin C levels of smokers without disease were significantly lower (p = 0,0000) than that of non-smokers. Vitamin C levels of CS-related cardiovascular patients were further lower (p = 0.0000) than that of smokers without disease.</p> <h3>Conclusions/Significance</h3><p>The results indicate that dietary supplementation of vitamin C may be a novel and simple therapy for the prevention of pathological cardiovascular events in habitual smokers.</p> </div

Assessment of apoptosis in the myocardium of CS-exposed guinea pigs and prevention by vitamin C.

<p>(Panel <b>A</b>) Release of cytochrome c from mitochondria to cytosol. Bottom panel indicates cropped SDS-PAGE with coomassie stain as the loading control. (Panel <b>B</b>) Quantitative estimation of cytochrome c of both fractions; * significantly increased (p<0.05) in cytosolic fraction with respect to AIR exposed sham controls; ** significantly decreased (p<0.05) in mitochondrial fraction with respect to AIR exposed sham controls. (Panel <b>C</b>) Overexpression of pp53 (phospho-p53), Bax, and formation of cleaved caspase 3 (CC3). (Panel <b>D)</b> Formation of cleaved caspase 8 (CC8). (Panel <b>E</b>) TUNEL positive cells in the myocardium (green fluorescence); respective lower rows stained with, 6-diamidino-2-phenylindole (DAPI) (magnification 200X). (Panel <b>F</b>) Quantitative evaluation of TUNEL positive cells; bars over the columns indicate means ± SEM (n = 6); * significantly increased (p<0.05) with respect to AIR exposed sham controls. Vit C means vitamin C.</p