Pramod Kumar Avti

Kinetics of 14carbon dioxide excretion from 14C-urea by oral commensal flora

Background and Aim:  Previous studies have shown that while performing the 14C‐urea breath test (14C‐UBT) for the detection of Helicobacter pylori (H. pylori), there is possibility of false‐positive results due to the other urease producing bacteria present in oropharynx, if breath samples are obtained within 30 min after administration of non‐capsulated 14C‐urea. Therefore, we have exclusively evaluated the kinetics of 14carbon dioxide (14CO2) excretion by oral commensal flora to theoretically propose optimum breath collection timings for 14C‐UBT.

Effect of esomeprazole on the pharmacokinetics of carbamazepine

Objective: Present study was carried out to evaluate effect of esomeprazole on the pharmacokinetics of carbamazepine in rabbits. Materials and Methods: Study was conducted at Department of Pharmacology, Postgraduate Institute of Medical Education and Research from March to October 2007. In a parallel design study, carbamazepine 40 mg/kg/day was given orally for 14 days. On day 15, blood samples were taken at various time intervals between 0 and 24 hours. In esomeprazole group, carbamazepine was administered for 14 days as above. On day 8, esomeprazole 2.8 mg/kg/day along with carbamazepine 40 mg/kg/day was administered till 14 days and blood samples were drawn on 15th day. Plasma levels of carbamazepine were assayed by high-performance liquid chromatography and pharmacokinetic parameters were calculated. Results: In all groups there was a decrease in the AUC0-24 when carbamazepine was coadministered with esomeprazole. The decrease in AUC0-24 (22.78 ± 4.71 to 10.46 ± 2.29), Cmax (2.76 ± 0.77 to 1.412±1.08), Tmax (2.83 ± 0.17 to 3 ± 0.40) was statistically significant (P < 0.05) when esomeprazole was given along with carbamazepine. Additionally, absorption and elimination constant were also altered significantly. Conclusions: These results suggest that concomitant use of esomeprazole alters the pharmacokinetics of carbamazepine. Confirmation of these results in human studies will warrant changes in carbamazepine dose or frequency when esomeprazole is coadministered.

Intestinal inflammation and seizure susceptibility: understanding the role of tumour necrosis factor-α in a rat model

Objectives The aim of the study was to evaluate the correlation between colitis and susceptibility to seizures.

Role of neuroimaging in drug development.

Abstract The development of new molecular imaging techniques has bridged the gap between preclinical and clinical research. During the last decade, the developments in imaging strategies have taken a great leap by the advancements in new imaging scanners, development of pharmaceutical drugs, diagnostic agents, and new therapeutic regimens that made significant improvements in health care. The knowledge gained from imaging techniques in preclinical research can be applicable to the patients. Similarly, the problems from clinical studies with humans can be tested and studied in preclinical studies. The appropriate application of molecular imaging to drug discovery and development can markedly reduce costs and the time required for new drug development. Some imaging techniques, such as computed tomography (CT) or magnetic resonance imaging (MRI), reveal anatomical images, and single-photon emission computed tomography (SPECT), SPECT/positron emission tomography (PET), and PET show functional images. These developing molecular or neuroimaging methods provide increasingly detailed structural and functional information about the nervous system. The basic principles of each technique are described followed by examples of the current applications to cutting-edge neuroscience research. In summary, it is shown that neuroimaging continues to grow and evolve, embracing new technologies and advancing to address ever more complex and important neuroscience questions.

Therapeutic potential of arachidonyl trifluromethyl ketone, a cytosolic phospholipaseA2 IVA specific inhibitor, in cigarette smoke condensate-induced pathological conditions in alveolar type I & II epithelial cells

Cigarette smoke is responsible for multiple disorders and causes almost 10 million annual deaths globally but underlying mechanisms are still underexplored. Continuous exposure of Cigarette smoke condensate (CSC) leads to cytosolic phospholipase A2 (cPLA2) mediated high free radicals where cPLA2s seems to play crucial role in generated various patho-physiological conditions such as chronic inflammation, oxidative stress and cancer. In this view, we assessed the therapeutic potential of arachidonyl trifluromethyl ketone (ATK), a cPLA2 inhibitor, via pharmacological inhibition of most expressible CSC-induced cPLA2 group IVA in type-I and type-II alveolar epithelial cells. The In Vitro inhibitory effect of ATK on CSC-induced PLA2 activity and its cellular role were assessed in terms of cell viability, fluorescein diacetate (FDA) dye uptake assay for membrane integrity, reactive oxygen species (ROS)/reactive nitrogen species (RNS) levels and pro apoptotic as well as anti apoptosis markers via flow cytometry, along with extracellular signal-regulated kinases (ERK) levels using enzyme-linked immunosorbent assay (ELISA). The experimental findings demonstrated that ATK acts as potent inhibitor of cPLA2 activity and shown its effectiveness as therapeutic agent by significantly mimicking CSC-induced levels of free radicals, primary apoptosis, ratio of pro-apoptotic/apoptotic proteins and levels of ERK whereas protected cells from loss of cell viability and membrane integrity. Thus, this study is an important step towards the opening up of avenues for the applicability of the cPLA2 isoform specific inhibitors such as ATK for pre-clinical and clinical studies and could be beneficial during smoking-induced lung pathological conditions.

PO-239 Benzo(a)pyrene, an active product of cigarette smoke, role in PLA2 isoforms activation in colon cancer

Introduction One of the active combustion product of cigarette smoke, Benzo[a]pyrenes, role in pulmonary cancer is clearly understood. However, its role in gastrointestinal cancer including colon cancer is not clearly understood. Material and methods In this study, benzo(a)pyrene’s was treated to colon cells to evaluate its role in cell viability, cellular ROS, and gene expression of various PLA2 isoforms was evaluated by FACS and PCR. The identified PLA2 was silenced at the gene level to evaluate its role in cell viability and ROS generation. Results and discussions B(a)P treatment at 1 µg/ml for 48 hour to HCT-15 male colon cells significantly reduced the cell viability without affecting HT-29 female colon cells. Higher doses and longer treatment duration with B(a)P showed that female colon cells were highly sensitive than male colon cells. Annexin-V/PI staining for pre-apoptotic detection showed that B(a)P treatment increased the apoptosis in both the cell types in a concentration and time-dependent manner. The cytosolic ROS (cROS) and superoxide radical (SOR) formation in the female colon cells was significantly higher than male colon cells unlike the mitochondrial ROS (mtROS) production which was significantly higher in male colon cells. Treatment with B(a)P significantly upregulated the IID and IVA PLA2 isoform groups in HCT-15 male colon cells, whereas IB was upregulated in HT-29 female colon cells among the various PLA2 isozyme gene studied (IB, IID, III, IVA, IVB, IVC, VI, X, aiPLA2 and iPLA2). Gene silencing experiments targeting PLA2 IID and IVA in the HCT-15 male colon cells and IB in HT-29 female colon cells showed no effect with B(a)P treatment on the cell proliferation, apoptosis, membrane integrity and free radicals (ROS, mtROS, and SOR) generation. Conclusion Targeting specific PLA2 isozymes in a cell specific manner abolished the B(a)P-induced PLA2 mediated oxidative damage related signalling pathways.

SU‐E‐T‐20: Differential Modulation of Antioxidant Defense System in Various Organs of Balb/c Mice by Whole Body Exposure to Low‐Dose Gamma Radiation

Purpose: To evaluate the effect of low‐dose (< 50 cGy) whole body gamma irradiation on antioxidant defense system enzymes in the liver,lung and kidney of Balb/c mice at various post‐irradiation intervals. We examined the critical level of radiation dose and the degree to which these changes remain affected in these organs after irradiation. Methods: Young male Balb/c mice (5–6 wks), were divided into irradiated and non‐irradiated groups. Whole body irradiation was done with gamma rays from a , 60 Cobalt source at doses of 10, 25 and 50 cGy (48.78 cGy/min). Lipid peroxidation and antioxidant defense enzymes (reduced glutathione, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase) were measured in liver,lung and kidney at 4, 12 and 24 hr after irradiation.Results: Lipid peroxidation increased by 1.38, 2.0 and 1.33 folds in lung,liver and kidney respectively at 12 hrs after exposure to 25 cGy. Reduced glutathione increased significantly in all these organs at 12 hrs after exposure of the animals at these doses as compared to control. Superoxide dismutase activity increased in liver and kidney up to 1.37 folds at 12 hrs of exposure at these doses. The antioxidant enzyme activities of catalase, glutathione peroxidase and glutathione reductase also increased between 1.1 and 1.3 folds in kidney and liver of mice at these doses. Interestingly, the activities of these enzymes remained unaltered in the lung after exposure of the animals at different doses Conclusions: Low‐dose whole body irradiation differentially modulates the antioxidant defense system in liver,lungs and kidneys of mice which may be due to variable sensitivities in activation of the related genes in these organs. The induction of endogenous glutathione immediately after exposure to low‐dose gamma irradiation, may be beneficial in protecting the cells from the reactive oxygen species (ROS) induced oxidative stress in various ROS‐related diseases Funds for conducting this project were provided by Director, Post Graduate Institute of Medical Education and Research, Chandigarh, India.