NMR based Serum metabolomics revealed metabolic signatures associated with oxidative stress and mitochondrial damage in brain stroke.

Brain stroke (BS, also known as a cerebrovascular accident), represents a serious global health crisis. It has been a leading cause of permanent disability and unfortunately, frequent fatalities due to lack of timely medical intervention. While progress has been made in prevention and management, the complexities and consequences of stroke continue to pose significant challenges, especially, its impact on patient's quality of life and independence. During stroke, there is a substantial decrease in oxygen supply to the brain leading to alteration of cellular metabolic pathways, including those involved in mitochondrial-damage, leading to mitochondrial-dysfunction. The present proof-of-the-concept metabolomics study has been performed to gain insights into the metabolic pathways altered following a brain stroke and discover new potential targets for timely interventions to mitigate the effects of cellular and mitochondrial damage in BS. The serum metabolic profiles of 108 BS-patients were measured using 800 MHz NMR spectroscopy and compared with 60 age and sex matched normal control (NC) subjects. Compared to NC, the serum levels of glutamate, TCA-cycle intermediates (such as citrate, succinate, etc.), and membrane metabolites (betaine, choline, etc.) were found to be decreased BS patients, whereas those of methionine, mannose, mannitol, phenylalanine, urea, creatine and organic acids (such as 3-hydroxybutyrate and acetone) were found to be elevated in BS patients. These metabolic changes hinted towards hypoxia mediated mitochondrial dysfunction in BS-patients. Further, the area under receiver operating characteristic curve (ROC) values for five metabolic features (methionine, mannitol, phenylalanine, mannose and urea) found to be more than 0.9 suggesting their high sensitivity and specificity for differentiating BS from NC subjects.

A Eu3+doped functional core-shell nanophosphor as fluorescent biosensor for highly selective and sensitive detection of dsDNA.

Lanthanide-doped core-shell nanomaterials have illustrated budding potential as luminescent materials, but their biological applications have still been very limited due to their aqueous solubility and biocompatibility. Here, we report a simple and cost-effective approach to construct a water-stable chitosan-functionalized lanthanoid-based core shell (Ca-Eu:Y2O3@SiO2) nanophosphor. The as-synthesized Ca-Eu:Y2O3@SiO2-chitosan (CEY@SiO2-CH) nanophosphor has been characterized for its structural, morphological, and optical properties, by employing different analytical tools. This sensing platform is suitable for dsDNA probing by tracing the "turn on" fluorescence signal generated by CEY@SiO2-CH nanophosphor with the addition of dsDNA. The ratio of fluorescence intensity enhancement is proportional to the concentration of dsDNA in the range 0.1-90 nM, with the limit of detection at ⁓16.1 pM under optimal experimental conditions. The enhancement in fluorescence response of functionalized core-shell phosphor with dsDNA is due to the antenna effect. Additionally, response of probe has been studied for the real samples displaying percent recovery in between 101 and 105, maximum RSD% upto 5.23 (n = 3). This outcome can be applied to the selective sensing of dsDNA through optical response. These findings establish the CEY@SiO2-CH a simple, portable, and potential candidate as a sensor for rapid and analytical detection of dsDNA.

Vitamin D and inflammatory cytokines association in mild cognitive impaired subjects.

BACKGROUND: Mild cognitive impairment (MCI) is a prodromal stage of Alzheimer's disease (AD). The association of low Vitamin D and chronic inflammation in the onset of cognitive decline in the elderly population has been established but the variable population-based study is still lacking. METHODOLOGY: The present study aims to investigate the level of plasma Vitamin D, pro-inflammatory cytokines IL-1ß, IL-6, TNF-α, cognitive performance, and white matter changes in the elderly population in the North-Eastern part of Uttar Pradesh, India. RESULTS: 70 participants with (Mean age- 75.14 ± 1.24, Male/Female- 50/20) with an Mini Mental State Examination (MMSE) score of (24.82 ± 1.82) and Montreal Cognitive Assessment Test (MOCA) score (21.83 ± 1.75), were cognitive decline, against the 70 healthy controls (Mean Age-73.18 ± 1.43; Male/Female- 50/20) with MMSE score (28.1 ± 1.5) and MOCA (28.5 ± 1.65), White matter variable Fractional Anisotropy (FA) and Apparent Diffusion Coefficient (ADC) values in MCI subject was found significantly altered in Right temporal lobe, Corpus Callosum (Right) and Hippocampus body (Right), Hippocampus body (left), Hippocampus head (Right) and Hippocampus head (Left)as compared with healthy controls. The level of cytokines IL-1ß, IL-6, TNF-α, was significantly high in MCI subjects as compared with controls. Further lower Vitamin D level in plasma was detected in MCI as compared with healthy controls. CONCLUSION: The result from the present study depicts that chronic inflammation and lower Vitamin D level influences neurodegeneration and decline in cognitive performance in the elderly population. These variables can be used as biomarkers for early identification of AD and interventional strategies can be designed for prevention at the prodromal stage of AD.

High-efficiency vertical fibre-to-polymer waveguide coupling scheme for scalable polymer photonic circuits.

Polymer photonic circuits offer a versatile platform for various applications, including communication, sensing and optical signal processing. Though polymers offer broadband, linear and nonlinear optical properties, the coupling between an optical fibre and a polymer waveguide has been a challenge. In this work, we propose and demonstrate a wafer-scale vertical coupling scheme for polymer waveguides. The scheme uses a silicon nitride grating coupler with an inverse taper to couple between an optical fibre and a SU8 polymer waveguide. We demonstrate a maximum coupling efficiency of -3.55 dB in the C-band and -2.92 dB in the L-band with a 3-dB bandwidth of 74 and 80 nm, respectively. A detailed design and simulation, fabrication, and characterisation results are presented. The scheme demonstrates a scalable and efficient surface grating approach for polymer photonic integrated circuits.

An elaborative NMR based plasma metabolomics study revealed metabolic derangements in patients with mild cognitive impairment: a study on north Indian population.

Mild cognitive impairment (MCI) is transition phase between cognitive decline and dementia. The current study aims to investigate altered metabolic pattern in plasma of MCI for potential biomarkers. MCI (N = 50) and healthy controls (HC, N = 50) age group 55-75 years were screened based on Mini Mental State Examination Test (MMSE) and diffusion tensor imaging (DTI imaging). The MMSE score of MCI was significantly lower (25.74 ± 1.83) compared to healthy control subjects (29 ± 1). The MCI patients exhibit significant changes in white matter integrity in the right frontal lobe, right temporal lobe, left frontal lobe, forcep major, fornix, corpus callosum. Further, the plasma samples of twenty seven MCI patients (N = 27) and twenty HC subjects (N = 20; having no significant differences in any demographics) were analyzed using 1H NMR based metabolomics approach. Consistent with many previous reports, the levels of several plasma metabolites were found to be elevated in MCI patients compared to healthy controls. Further univariate and multivariate ROC curve analyses provided three plasma metabolites as a diagnostic panel of biomarker for MCI; which are lysine, glycine, and glutamine. Overall, the results of this study will help to improve the diagnostic and prognostic strategies of MCI in addition to improving our understanding about disease pathogenesis. We believe that the over-nutritional metabolic phenotype of MCI needs to be targeted for developing future dietary interventions so that the progression of MCI can be limited. Metabolic derangements associated with Mild Cognitive Impairment.

Frontotemporal dementia: an unusual cause.

Intracerebral pneumocephalus is commonly associated with head and facial trauma, ear infection, tumors and surgical interventions. Osteomas are relatively common, benign tumors that occur mainly in the paranasal sinuses, the frontal sinus in particular. Pneumocephalus has been commonly reported with frontal osteoma but isolated presentation as frontotemporal dementia is uncommon. Patient was admitted with complaints of change of behavior and forgetfulness for the last one year. He had progressively become more apathetic and presented with behavioral abnormalities. General physical examinations were within normal limits including the motor and sensory system although neuropsychiatry assessments were below the average level, with features of dementia. Further, MRI brain revealed pneumocephalus in bilateral frontal lobe. CT cisternography revealed a well defined lobulated densely sclerotic lesion of approximate size 20 × 17 × 27mm transverse and cranio-caudal axis respectively arising from right ethmoid sinus. Clinically, the association of pneumocephalus and isolated presentation as frontotemporal dementia has not been described to the best of our knowledge. A single case has been described with ethmoid osteoma. Radiological features were suggestive of osteoid osteoma. The uniqueness of the case is the development of dementia with frontotemporal involvement and resemblance with Frontotemporal Dementia. This is the only case with dementia and pneumocephalus (secondary to osteoid osteoma) to best of our knowledge.

Diffusion tensor imaging based white matter changes and antioxidant enzymes status for early identification of mild cognitive impairment.

Mild cognitive impairment (MCI) is an early stage of dementia. The changes in white matter integrity and antioxidant enzymes levels are crucial in onset and progression to Alzheimer's disease (AD). To elucidate the changes in cognitive performance, white matter integrity, oxidative stress marker, for early detection of prodromal state of AD. Fifty cases of MCI and controls (55-75 years) were subjected to Mini Mental State Examination (MMSE), diffusion tensor imaging (DTI) followed by estimation of superoxide dismutase, glutathione peroxidase and lipid peroxidation in serum of MCI and control population. The MMSE scores of MCI subjects were (28±2 - 22.6±1) as compared with controls (28±1- 29±1). DTI metrics fractional anisotropy (FA) values in right and left frontal lobe, fornix, corpus callosum, while apparent diffusion coefficient (ADC) values in right temporal lobe, hippocampus head, corpus callosum right, and forcep major were significantly altered in MCI as compared with controls. Superoxide dismutase, glutathione peroxidase level were lower while lipid peroxidation marker malondialdehyde (MDA) was increased in patients with MCI as compared with controls. The study emphasized that changes in neuro-psychological performance, white matter integrity and antioxidant enzymes level provide early signature for diagnosis of MCI.

Proteomics based identification of differential plasma proteins and changes in white matter integrity as markers in early detection of mild cognitive impaired subjects at high risk of Alzheimer's disease.

Mild cognitive impairment (MCI) is an intermediate stage of cognitive decline and dementia. The absence of specific diagnostic test for identification of MCI and AD. The current study aims to find proteomics based change in plasma proteins and diffusion tensor imaging (DTI) based white matter changes in MCI for early detection of prodromal Alzheimer's disease. Fifty cases of mild cognitive impairment and age matched control between (55-75 yrs) were screened on basis of Mini Mental State Examination (MMSE). Two dimensional gel electrophoresis and DTI imaging was performed in MCI and age matched control. The MMSE score of MCI were in the range of (28 ±â€¯2-22.6 ±â€¯1) as compared with healthy control (28 ±â€¯2), DTI metrics apparent diffusion coefficient (ADC) and fractional Anisotropy (FA) has shown significant changes in fornix, corpus callosum, hippocampus, right temporal and right frontal lobe, left frontal lobe, forcep major of MCI subjects as compared with controls. The protein expression of keratin type-2 was up regulated and albumin was down regulated in MCI subjects as compared with control. The data from present study signifies that expression of Keratin type-2 and albumin along with white matter changes provides early signatures for identification of MCI at high risk of Alzheimer's disease.

Candidemia-induced pediatric sepsis and its association with free radicals, nitric oxide, and cytokine level in host.

Candida species has become the seventh most frequent causal microorganisms of nosocomial sepsis. Prematurity and low birth weights are strongly associated with the development of neonatal nosocomial bloodstream infections. Candida albicans has been the species most often associated with neonatal infections, but recently, there has been a changing pattern in the isolates recovered from neonates with invasive candidiasis, which poses resistance to the existing class of azoles such as fluconazole antifungals along with cross resistance to newer triazoles, which results in a therapeutic challenge in invasive fungal infections causing high incidence of mortality. Candida species was isolated from blood of neonates and children younger than 15 years admitted to hospital and susceptible for Candida-induced sepsis. Polymerase chain reaction-based identification and confirmation of individual Candida species were done using DNA sequencing. Antibiotic susceptibility assay and resistance pattern for fluconazole, voriconazole, and amphotericin were done for all the isolates. Furthermore, the change in free radical, cytokine release, and nitric oxide synthase expression and nitric oxide release from polymorphonuclear leukocytes isolated from control and pediatric sepsis cases were also performed. The present study probably for the first time reports the change in increasing incidence of nonalbicans Candida-induced sepsis in neonates and children admitted to the intensive care unit of hospital, and current antibiotics load posing resistance for antifungal treatment strategy and provide serious threats in future treatment. The increase in free radicals in polymorphonuclear leukocytes and increase in expression of nitric oxide synthase expression and nitric oxide release in Candida-infected pediatric sepsis cases underlie the role of host factor in dissemination and invasiveness of infection from exogenous sources and pathogenesis of systemic inflammation during sepsis.

Proteomics-based identification of plasma proteins and their association with the host-pathogen interaction in chronic typhoid carriers.

BACKGROUND: Current diagnostic tests are inadequate to detect typhoid cases, as well as the chronic carrier state, the sole reservoir of Salmonella enterica serovar Typhi. The current study was conducted to find new molecular signatures of pathogen/disease to understand the mechanism behind the host-pathogen interaction in enteric fever. METHODS: Proteomics-based studies were done to determine the expression of differentially expressed proteins in the plasma of controls, acute typhoid cases, and chronic typhoid carriers. Further, transcriptome-based analysis using reverse-transcriptase PCR (RT-PCR) was done in controls, acute typhoid cases, and chronic typhoid carriers. RESULTS: Results showed the upregulation of proprotein convertase subtilisin, furin, haptoglobin, and albumin in the plasma of chronic typhoid carriers. The elevation in mRNA expression of four differentially expressed proteins confirms the changes at the transcriptional level. Further, the increase in albumin and haptoglobin in chronic typhoid carriers shows their role in free radical generation, inflammation, and monocyte cell signaling. CONCLUSION: Through proteomics techniques, this study identified four proteins in the chronic typhoid carrier host that may have a role in the disease pathogenesis of enteric fever.

Extracellular activation of arginase-1 decreases enterocyte inducible nitric oxide synthase activity during systemic inflammation.

Liver dysfunction secondary to severe inflammation is associated with the release of enzymes normally sequestered within hepatocytes. The purpose of these studies was to test the hypothesis that these enzymes are released, at least in part, to modulate potentially deleterious inflammatory processes in distant tissues like the gut. Human Caco-2(BBe) enterocyte-like cells were exposed to cytomix (IFN-gamma, TNF-alpha, and IL-1beta) in the absence or presence of human liver cytosol (LC). Nitric oxide (NO(*)) and inducible nitric oxide synthase (iNOS) protein production were measured by the Griess assay and Western analysis, respectively. Cytomix induced the expression of iNOS and release of NO(*). LC protein (400 microg/ml) added to the basal compartment but not apical compartment completely blocked the release of NO(*) but only slightly decreased the magnitude of iNOS protein induction. Ultrafiltration and ultracentrifugation studies demonstrated that microsome-associated arginase-1 activity was the iNOS-suppressing activity in LC. Liver arginase required activation by a <10-kDa factor that was present in supernatants of cytomix-stimulated cells. The selective iNOS inhibitor l-N(6)-(1-iminoethyl)-lysine.2HCl prevented production of this factor. The biotin switch assay detected increased S-nitrosylation of arginase-1 after incubation with supernatants from immunostimulated Caco-2 cells. Serum from endotoxemic mice contained significantly greater arginase activity compared with serum from control mice. Furthermore, the ratio of mucosal monomeric to dimeric iNOS increased in endotoxemic mice compared with controls. Thus reciprocal activation of arginase-1 and modulation of mucosal iNOS activity may be protective because it would be expected to decrease NO(*)-dependent intestinal barrier dysfunction on that basis.

Resveratrol modulates pyrogallol-induced changes in hepatic toxicity markers, xenobiotic metabolizing enzymes and oxidative stress.

Previously, we reported that pyrogallol, an anti-psoriatic agent, causes hepatotoxicity in experimental animals and silymarin, an herbal antioxidant, reduces pyrogallol-induced changes [Upadhyay, G., Kumar, A., Singh, M.P., 2007. Effect of silymarin on pyrogallol- and rifampicin-induced hepatotoxicity in mouse. Eur. J. Pharmacol. 565, 190-201.]. The present study was undertaken to assess the effect of resveratrol against pyrogallol-induced changes in hepatic damage markers, xenobiotic metabolizing enzymes and oxidative stress. Swiss albino mice were treated intraperitoneally, daily with pyrogallol (40 mg/kg), for one to four weeks, along with respective controls. In some set of experiments, animals were pre-treated with resveratrol (10 mg/kg), 2 h prior to pyrogallol treatment, along with respective controls. Alanine aminotransaminase, aspartate aminotransaminase and bilirubin were measured in blood plasma and mRNA expression of cytochrome P-450 (CYP) 1A1, CYP1A2, CYP2E1, glutathione-S-transferase (GST)-ya and GST-yc, catalytic activity of CYP1A1, CYP1A2, CYP2E1, GST, glutathione reductase and glutathione peroxidase, lipid peroxidation and reduced glutathione (GSH) level were measured in liver. Resveratrol reduced pyrogallol-mediated increase in alanine aminotransaminase, aspartate aminotransaminase, bilirubin, lipid peroxidation and mRNA expression and catalytic activity of CYP2E1 and CYP1A2. Pyrogallol-mediated decrease in GST-ya and GST-yc expressions, GST, glutathione peroxidase and glutathione reductase activities and GSH content was significantly attenuated in resveratrol co-treated animals. CYP1A1 expression and catalytic activity were not altered significantly in any treated groups. The results demonstrate that resveratrol modulates pyrogallol-induced changes in hepatic toxicity markers, xenobiotic metabolizing enzymes and oxidative stress.

The involvement of secondary signaling molecules in cytochrome P-450 1A1-mediated inducible nitric oxide synthase expression in benzo(a)pyrene-treated rat polymorphonuclear leukocytes.

Benzo(a)pyrene induces cytochrome P-450 1A1 (CYP1A1) expression in rat polymorphonuclear leukocytes (PMNs) that upregulates expression of inducible nitric oxide synthase (iNOS). In the present study, the involvement of secondary signaling molecules in CYP1A1-mediated augmentation of iNOS expression in benzo(a)pyrene-treated rat PMNs was investigated. PMNs were isolated from the peripheral blood of controls and benzo(a)pyrene-treated rats. The expression and/or activity of CYP1A1, iNOS, tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1beta), and intracellular calcium ([Ca(2+)]i) concentrations were measured in control and benzo(a)pyrene-treated rat PMNs with and without alpha-naphthoflavone, aminoguanidine, genistein, pyrrolidine dithiocarbamate (PDTC), felodipine, or SB202190 pre-treatment. A significant elevation in CYP1A1 and [Ca(2+)]i was observed in benzo(a)pyrene-treated rat PMNs, which was significantly restored by alpha-naphthoflavone or genistein. Neither PDTC, SB202190, nor aminoguanidine altered the benzo(a)pyrene-mediated increase in [Ca(2+)]i. Although felodipine reduced the benzo(a)pyrene-mediated increase in [Ca(2+)]i, no significant change was observed in CYP1A1 expression and activity. Benzo(a)pyrene-augmented iNOS expression and activity in PMNs were significantly reverse by felodipine, genistein, or PDTC. Benzo(a)pyrene also induced TNF-alpha and IL-1beta production in PMNs, which was significantly reversed by genistein. The results demonstrated the involvement of [Ca(2+)]i, tyrosine kinase, inflammatory cytokines, and NF-kappaB in CYP1A1-mediated iNOS expression in benzo(a)pyrene-treated rat PMNs.

Effect of silymarin on pyrogallol- and rifampicin-induced hepatotoxicity in mouse.

Rifampicin and pyrogallol, besides beneficial effects, elicit hepatotoxicity in experimental animals and humans. The present investigation was undertaken to elucidate the role of drug/toxicant-metabolizing enzymes in rifampicin- and pyrogallol-induced hepatotoxicity and the effect of silymarin, a herbal antioxidant, on rifampicin- and pyrogallol-induced alterations in mouse liver. Male Swiss albino mice were treated intraperitoneally with and without rifampicin (20 mg/kg) and/or pyrogallol (40 mg/kg) for 1, 2, 3 and 4 weeks. In some experiments, animals were treated with silymarin (40 mg/kg), 2 h prior to rifampicin and/or pyrogallol. The differential expression and catalytic activity of cytochrome P-450 (CYP) 1A1, CYP1A2 and CYP2E1, the activity of glutathione-S-transferase, glutathione peroxidase and glutathione reductase, and lipid peroxidation were measured in the liver of control and treated groups. CYP1A1 expression and catalytic activity were not altered following individual or combinational treatment. A significant augmentation in the expression and activity of CYP1A2 and CYP2E1 was observed following pyrogallol and rifampicin+pyrogallol treatment; however, rifampicin exhibited a significant induction of CYP2E1 only. Attenuation of glutathione-S-transferase, glutathione reductase and glutathione peroxidase activities and augmentation of lipid peroxidation were observed following rifampicin and/or pyrogallol treatment and a cumulative effect was seen when the two drugs were administered in combination. Silymarin restored the rifampicin- and/or pyrogallol-induced alterations in the expression and activity of CYP1A2 and CYP2E1, the activity of glutathione-S-transferase, glutathione reductase, and glutathione peroxidase, and lipid peroxidation. The results demonstrate the role of CYP1A2, CYP2E1, glutathione-S-transferase, glutathione reductase and glutathione peroxidase in rifampicin- and pyrogallol-induced hepatotoxicity and provide evidence for the involvement of silymarin in attenuation of drug-induced hepatotoxicity.

A study on the association of cytochrome-P450 1A1 polymorphism and breast cancer risk in north Indian women.

Cytochrome P-450 1A1 (CYP1A1) is involved in the 2-hydroxylation of estrogens and mammary carcinogens into 2-hydroxy catechol metabolites. Many commonly occurring single nucleotide polymorphism (SNP) are reported in CYP1A1 in various populations that include, isoleucine to valine substitution at 462 codon in heme binding region in exon 7 (A to G transition at position 2455; M2), threonine to asparagine substitution at codon 461 (C to A transversion at position 2453; M4), T to C transition at 3801 position (M1) and T to C transition at position 3205 (M3) in 3' non-coding region. Epidemiological studies have shown inconsistent patterns between CYP1A1 polymorphism and breast cancer risk among various populations. Most of the studies have shown significant association between CYP1A1 genotype polymorphism and breast cancer risk. The present investigation was therefore undertaken to investigate the association of M1, M2, M3 and M4 polymorphisms and their subsequent contribution in premenopausal and postmenopausal women with breast cancer risk in north Indian women. Genomic DNA was isolated from case controls and breast cancer patients, specific segments of genomic DNA were amplified and restriction fragment length polymorphism (RFLP) was performed. CYP1A1 expression and catalytic activity were also assessed in premenopausal and postmenopausal case controls and patients. Polymorphism at M1, M2 and M4 alleles was detected and odds ratio for W/M1 and M1/M1 was calculated as 1.07 (95% CI, 0.59-1.87) and 0.74 (95% CI, 0.28-1.96) respectively. Odds ratio for W/M1 and M1/M1 alleles in premenopausal and postmenopausal women was 1.09 (95% CI, 0.45-2.49)/0.62 (95% CI, 0.10-2.66) and 1.60 (95% CI, 0.60-4.22)/1.06 (95% CI, 0.22-7.33) respectively. Odds ratio for W/M4 and M4/M4 allele was 1.20 (95% CI, 0.65-2.24)/4.55 (95% CI, 0.44-226.2) and 0.96 (95% CI, 0.36-2.64)/4.51 (95% CI, 0.23-273.0) respectively in total and premenopausal women. In postmenopausal women odds ratio was calculated as 1.16 (95% CI, 0.45-2.94) for M4/W but it could not be detected for M4/M4 since this genotype was not found in any postmenopausal case controls. Odds ratio for W/M2 genotype was calculated 0.57 (95% CI, 0.28-1.02), 1.06 (95% CI, 0.40-2.47) and 0.33 (95% CI, 0.12-0.89) respectively for total, premenopausal and postmenopausal women, however, in any group the odds ratio for M2/M2 could not be detected as M2/M2 genotype was not found in breast cancer patients. Polymorphism at M1 and M4 alleles was not found significantly associated with breast cancer risk and only wild type genotype was found in case controls and patients for M3 allele. Lack of protective association between CYP1A1 M2 genotype was also observed, however, in postmenopausal women a significant protective association with breast cancer risk was found (odds ratio, 0.33; 95% CI, 0.12-0.89; P-value 0.03). Similarly, no significant alteration in CYP1A1 expression and catalytic activity was observed in wild type and variant genotypes both in premenopausal and postmenopausal patients as compared with their respective controls. The results obtained from the present investigation thus suggest that probably CYP1A1 (M1, M2, M3, and M4) polymorphism alone does not play a significant role in the breast cancer risk in north Indian women.

Involvement of endogenous nitric oxide in myeloperoxidase mediated benzo(a)pyrene induced polymorphonuclear leukocytes injury.

The present study was undertaken to investigate the involvement of nitric oxide in the augmentation of benzo(a)pyrene induced cellular injury in polymorphonuclear leukocytes (PMNs). Polymorphs were isolated from the blood collected from Wistar rats treated with and without benzo(a)pyrene (50mg/kg, i.p.) through cardiac puncture. Catalase, superoxide dismutase (SOD), glutathione-s-transferase (GST), myeloperoxidase (MPO) and nitrite content were estimated in PMNs using standard procedures. Inducible nitric oxide synthase (iNOS) and cytochrome P-4501A1 (CYP1A1) expression in PMNs were also analyzed in presence or absence of nitric oxide synthase (NOS) inhibitors, aminoguanidine (AG, 5mM) and L-NG nitro L-arginine methyl ester (L-NAME, 1mM). A significant augmentation was observed in the nitrite content, activities of superoxide dismutase, MPO and GST and the expressions of iNOS and CYP1A1, however, catalase activity was attenuated in PMNs of benzo(a)pyrene treated rats as compared with their respective controls. AG and L-NAME resulted in a significant attenuation in nitrite content, MPO activity and iNOS expression; however, no significant alteration was observed in CYP1A1 expression. CYP1A1 inhibitor alpha-naphthoflavone inhibited the expression of iNOS in PMNs of benzo(a)pyrene treated animals significantly. The results obtained thus suggest that CYP1A1 induces iNOS expression leading to the generation of endogenous nitric oxide (NO) that could be responsible for the augmentation of myeloperoxidase-mediated benzo(a)pyrene-induced injury in PMNs.

Status of antioxidant defense system and expression of toxicant responsive genes in striatum of maneb- and paraquat-induced Parkinson's disease phenotype in mouse: mechanism of neurodegeneration.

Parkinson's disease (PD) is a progressive neurodegenerative disorder contributed by the combination of age, genetic and environmental factors. Several studies have clearly shown increase in the incidences of PD in the rural environments and hypothesized the involvement of pesticides such as paraquat and maneb in neurodegeneration. These studies have prompted researchers to develop paraquat and maneb models to study the effect of co-treatment of maneb and paraquat on neuronal toxicity; however, the mechanism underlying maneb and paraquat co-treatment induced neuronal toxicity has not yet been clearly understood. The involvement of cytochrome P4502E1 and glutathione S-transferases A4-4 enzymes in the detoxification of several pesticides such as atrazine, fenamirol, organophosphorous insecticide parathion, methoxychlor, diethyl dithiocarbamate and paraquat has been known. The contribution of CYP2E1 and GSTA4-4 in neuronal toxicity has also been reported. The present study was therefore undertaken to investigate the mechanism of maneb- and paraquat-induced neurodegeneration by estimating the level of antioxidant defense enzymes in the striatum and measuring the differential expressions of CYP2E1 and GSTA4-4 genes. Animals were treated with and without maneb (30 mg/kg, i.p.) or paraquat (10 mg/kg, i.p.) either alone or in combination in exposure time-dependent manner. A significant increase in catalase, glutathione S-transferase and lipid peroxidation in the striatum was found following 3, 6 and 9 weeks of co-treatment as compared with individual treatment or controls. Individual treatment of maneb or paraquat did not exhibit any significant alteration in CYP2E1 and GSTA4-4 expression up to 6 weeks; however, an augmentation in CYP2E1 and GSTA4-4 expression was observed in the animals exposed to maneb or paraquat for 9 weeks. Augmentation in the expression of CYP2E1 and GSTA4-4 was more pronounced in the animals treated with maneb and paraquat in combination for nine weeks. A significant reduction in the augmented lipid peroxidation in the striatum was observed when the striatum was pre-administered with CYP2E1 inhibitors; however, glutathione pre-administration induced lipid peroxidation. Results obtained from the present investigation suggest the involvement of CYP2E1 and GSTA4-4 in the augmentation of the lipid peroxidation thereby enhancing neurodegeneration.