Analysis of cell proliferation rate in Oral Leukoplakia and Oral Squamous Cell Carcinoma

Objectives: Assessment of the cell proliferation rate in tissues can be one of the markers for impending malignancy in precancers. The state of activation and the proliferation activity of the cells can be assessed by the frequency of silver stained Nucleolar Organiser regions (AgNOR) within the nuclei which is significantly higher in malignant cells. The present study was carried out to analyze the distribution of the AgNOR in oral leukoplakia (OL) and oral squamous cell carcinoma (OSCC), and in their various histological grades, and to assess if the AgNOR distribution could give information on the malignant potentiality in premalignant lesions and aggressiveness of the malignant lesions. Study design: The study specimens comprised of 35 archival cases, of which 15 cases were of OL and 20 cases of OSCC. The specimens were stained by hematoxylin and eosin and modified silver staining method of Ploton et al. for the Nucleolar Organiser Regions. The specimens were analyzed independently by the two observers and was further statistically analysed. Results: The mean AgNOR count in OL was 2.80 ±0.50 and in cases of OSCC was 5.71± 1.08. The mean AgNOR count in OL cases of mild dysplasia was 2.59 ±0.66, in moderate dysplasia was 2.92± 0.43 and in severe dysplasia was 2.79. The mean AgNOR count in cases of well differentiated OSCC was 5.73± 1.62 and in cases of moderately differentiated OSCC was 5.67±1.19. Conclusion: The mean AgNOR count was higher in cases of OSCC as compared to cases of OL, and the AgNOR counts increased with the increase in the grades of dysplasia indicating a higher proliferative rate with increase in dysplasi

Formation of robust and completely tunable resonant photonic band gaps

We identify different types of the photonic band gaps (PBGs) of two dimensional magnetic photonic crystals (MPCs) consisting of arrays of magnetic cylinders and study the different tunability (by an external static magnetic field) of these PBGs. One type of the band gaps comes from infinitely degenerate flat bands and is closely related to those in the study of plasmonics. In addition, such PBGs are magnetically tunable and robust against position disorder. We calcualte the transmission of the PBG's and found excellent agreement with the results of the photonic band structure calculation. Positional disorder of the lattice structure affects the different types of PBGs differently.Comment: 4 pages, 5 figure

A theoretical study of methanol oxidation mechanisms by methanol dehydrogenase enzymes for fuel cell applications

Enzymes are considered for electrochemical generation of power in fuel cells. Methanol dehydrogenase (MDH) is one such enzyme, which has been used as an anodic catalyst for a methanol-fed biofuel cell producing enough power for small electronic device applications. In practice, however, there are power output limitations associated with this MDH fuel cell, which may potentially be eliminated or reduced if the reactivity of this enzyme during the oxidation of methanol at the molecular level is clearly understood. Two mechanisms for the methanol oxidation process by MDH have been proposed in the literature, Addition-Elimination (A-E) and Hydride Transfer (H-T), but no agreement has been reached about what mechanism actually operates in reality. Also, it was suggested that ion-modified MDH, particularly Ba 2+-MDH enzyme, is more active towards oxidation of methanol than Ca 2+-MDH from experimental kinetic observations. In this dissertation, MDH active site models of varying sizes were tested for the A-E and H-T methanol oxidation in the presence of both Ca2+ and Ba2+. Potential energy surfaces for the reactions were calculated, and the feasibility of the suggested reaction mechanisms was judged by comparison with available experimental free energy barriers. By systematically increasing the size of the models, deeper insight into the details of the reactions was obtained, and the role of the various active site residues was also analyzed. Comparison of free energy barriers calculated for the rate-determining steps in this work for the A-E and H-T oxidation mechanisms with experimental Gibbs energy of activation by Ca2+-MDH showed that these two mechanisms may not be correctly proposed in the literature. Also, the reduction of barriers for the rate-determining steps in the presence of Ba2+ for A-E and H-T obtained with the best MDH active site model tested here is almost twice as much the experimental free energy reduction with Ba 2+-MDH for methanol oxidation. A modified first step of original H-T resulted in a newly proposed two-step H-T oxidation mechanism, where the barrier for the formation of final product, formaldehyde, during the first step is very much comparable (11.4 kcal/mol) to the experimental Gibbs energy of activation (8.5 kcal/mol). In the case of Ba2+ presence during this new mechanism, the free energy barrier is 6.2 kcal/mol, which is comparable to free energy of activation for oxidation of methanol by Ba2+-MDH (3.5 kcal/mol). The second and final step involving proton transfer in this Two-step H-T was observed to be mediated by a water molecule in the presence of both ions. Moreover, DFT-MD investigations on the reactant complex and necessary intermediates associated with all mechanisms also lead us to the conclusion that oxidation of methanol by MDH has a greater probability of proceeding through the two-step hydride transfer mechanism compared to proposed A-E and H-T

Fishers in Post-harvest Fisheries Sector in India : An Assessment of Socio-economic Status

This paper presents the results of study carried out during 2009-11, to assess literacy, health and income status of fishers in India with reference to postharvest sector which covered fishers in marketing and processing. The study covered five states and one union territory, covering 11 districts reaching 548 households. About 52.19% of the respondents fell in the age group of 36-55. The average male- female ratio was 1.03 and 66.61% of the families were in the small family category of 2-4 members. It was observed that the literacy rates among fishers in post-harvest sector in different states ranged from 63.74 to 95.81%. In general, the literacy rates were comparable to the national average. Maternal and child mortality were low in the sample studied and the average birth weight of infants was 2.68 kg. The average monthly income was Rs. 7027.45 with a daily income of Rs. 234.25. About 44.70% of the households had no savings and 47.81% of households were in debt

Depletion of glutathione and enhanced lipid peroxidation in the CSF of acute psychotics following haloperidol administration

Haloperidol administration for 2 weeks results in significant reduction in the concentration of GSH in the CSF. Concomitantly, the levels of lipid peroxidation products increased as evidenced by increased malondialdehyde levels. The malondialdehyde levels in the CSF prior to haloparidol administration were not significantly higher than that seen in CSF from normal controls (data not shown) suggesting that increased oxidative stress did not exist in these patients prior to haloperidol administration. All the patients included in the present study were drug naive and hence the changes observed in the glutathione and malon6ialdehyde levels in the CSF were indeed mediated by haloperidol administration. The only other medication that was administered namely, anticholinergic drug, trihexyphenidyl is not known to cause any oxidative stress. The present study thus demonsuates that haloperidol administration results in significant oxidative stress. The generation of the oxidative stress is probably due to the increased turnover of dopemine caused by typical neuroleptics. Increased dopamine turnover is also observed in Parkinson's disease and the combination therapy consisting of antioxidant vitamin E and monoamine oxidase inhibitor, deprenyl has been shown to offer limited protection against the progression of the disease (Parkinson Disease Study Group 1989). In the present study, all the 15 patients exhibited extrapyramidal symptoms although the time of onset, the duration and the severity of the side effects differed between patients. On the presumption that the oxidative stress generated by haloperidel may cause extrapyramidal symptoms, the present study in humans taken together with the evidence provided in our earlier studies on rats (Shivakumar and Ravindranath 1992,1993) may justify experimental coadministration of antioxidanls (e.g., vitamin E) with typical neuroleptics like haloperidol to prevent the acute side effects