Vitamin C in the Prevention and Treatment of Frostbite

Two series of experiments were conducted on rats to evaluate the effect of Vit C for prevention and treatment of frostbite. For studies on prevention, 45 rats were divided into 3 groups, as control, Vit C-short term and Vit C-long term. Frostbite was produced experimentally in both the hind limbs by exposing the animals at -15 degree centigrade for 1 h and the assessment of cold injury was done after 15 days. In another study on prevention, frostbite was produced on 20 rats twice, in each limb separately with and without Vit C therapy. The result showed that administration of Vit C for a short period prior to cold exposure period maintained higher rectal temperature and significantly reduced the incidence of frostbite. For studies on treatment, frostbite was produced experimentally in 4 groups of rats. Group I was treated as control, group II was administered 5 mg of Vit C/100 g bw (orally) daily for 15 days. rapid rewarming at 37 degree centigrade on the exposed limbs of group III animals was carried out immediately after cold exposure. Combination of rapid rewarming followed by C therapy was given to group IV. The degree of injury of various groups were compared statistically. Prolonged Vit C therapy as well as waterbath rewarming at body temperature immediately after cold exposure showed significant reduction in tissue damage. High dose of Vit C therapy preceded by rapid rewarming showed additional benefit in reducing the tissue loss

Use of Hyperbaric Oxygen in Experimental Frost-Bite

Frost bite produced in rates by exposing them to -15 degree calcius and the extent of injury in the hind limbs and the tail was assessed at the end of 15 days. Hyperoxic treatment at normal atmospheric pressure and 1.5 atmosphere was given to experimental groups for 30 minutes daily for seven days in a hyperoxic chamber immediately after cold exposure. The controls were not given any treatment. Single oxygen treatment at normal atmosphere pressure was of no value, however, repeated hyperoxic treatment showed limited improvement but repeated treatment for seven days with hyperbaric oxygen at 1.5 atmosphere showed distinct recovery of frozen parts

Free Radical Scavenging, Cytotoxic and Hemolytic Activities from Leaves of Acacia nilotica (L.) Wild. ex. Delile subsp. indica (Benth.) Brenan

Dietary intake of phytochemicals having antioxidant activity is associated with a lower risk of mortality from many diseases. Therefore, the aim of this study was to determine the free radical scavenging, cytotoxic and hemolytic activities of leaves of Acacia nilotica by using various methods. The results of the present study revealed that ethanol extract was the most effective and IC50 value was found to be 53.6 μg mL−1 for Vero cell lines and 28.9 μg mL−1 for Hela cell lines in cytotoxicity assays. The zone of color retention was 14.2 mm in β-carotene bleaching assay, which was as significant as positive control, butylated hydroxy toluene. None of the tested extracts possessed any hemolytic activity against rat and human erythrocytes revealing their cytotoxic mechanism and non-toxicity. Thus, only the ethanol extract could be considered as a potential source of anticancer and antioxidant compounds. Further phytochemical studies will be performed for specification of the biologically active principles

Underwater Breathing Apparatus

An independent closed circuit regenerative type of breathing apparatus has been developed for isolating the respiratory tract from the ambient medium for use during breathing by personnel working in underwater or polluted atmosphere. An oxygen reducer is used in the design of this apparatus for catering to the required flows of oxygen for breathing during use of the apparatus and thus avoiding oxygen poisoning. The paper describes some of the salient aspects of the breathing apparatus to be deployed for submariners and other diving personnel of the Indian Navy and its potential usefulness as a life saving equipment

Explaining the Atypical Reaction Profiles of Heme Enzymes with a Novel Mechanistic Hypothesis and Kinetic Treatment

Many heme enzymes show remarkable versatility and atypical kinetics. The fungal extracellular enzyme chloroperoxidase (CPO) characterizes a variety of one and two electron redox reactions in the presence of hydroperoxides. A structural counterpart, found in mammalian microsomal cytochrome P450 (CYP), uses molecular oxygen plus NADPH for the oxidative metabolism (predominantly hydroxylation) of substrate in conjunction with a redox partner enzyme, cytochrome P450 reductase. In this study, we employ the two above-mentioned heme-thiolate proteins to probe the reaction kinetics and mechanism of heme enzymes. Hitherto, a substrate inhibition model based upon non-productive binding of substrate (two-site model) was used to account for the inhibition of reaction at higher substrate concentrations for the CYP reaction systems. Herein, the observation of substrate inhibition is shown for both peroxide and final substrate in CPO catalyzed peroxidations. Further, analogy is drawn in the “steady state kinetics” of CPO and CYP reaction systems. New experimental observations and analyses indicate that a scheme of competing reactions (involving primary product with enzyme or other reaction components/intermediates) is relevant in such complex reaction mixtures. The presence of non-selective reactive intermediate(s) affords alternate reaction routes at various substrate/product concentrations, thereby leading to a lowered detectable concentration of “the product of interest” in the reaction milieu. Occam's razor favors the new hypothesis. With the new hypothesis as foundation, a new biphasic treatment to analyze the kinetics is put forth. We also introduce a key concept of “substrate concentration at maximum observed rate”. The new treatment affords a more acceptable fit for observable experimental kinetic data of heme redox enzymes

26th Annual Computational Neuroscience Meeting (CNS*2017): Part 3 - Meeting Abstracts - Antwerp, Belgium. 15–20 July 2017

This work was produced as part of the activities of FAPESP Research,\ud Disseminations and Innovation Center for Neuromathematics (grant\ud 2013/07699-0, S. Paulo Research Foundation). NLK is supported by a\ud FAPESP postdoctoral fellowship (grant 2016/03855-5). ACR is partially\ud supported by a CNPq fellowship (grant 306251/2014-0)

Biotechnology in defence (Review Paper)

Biotechnology, in its present perspective, encompasses activities, such as recombination of genes; cloning, or making genetically identical copies of a living thing; and splicing of genes from DNA of one organism into the genome of unrelated species, to create new, self-reproducing forms of life. The vast potential of biotechnology is being increasingly realised, and efforts are in progress to harness it for improving quality and quantity of bio-weapons, The bio-weapons, as such, are highly attractive because of their non-detection by routine security systems, ease of access, low production cost and easy transportation, A wide range of genetically manipulated organisms and their by-products are considered to have an added advantage, because these genetically manipulated biologics not only accentuate the existing properties of bio-weapons, but also could be made target-specific. Biotechnology, if used prudently, can play a significant role to counter such threats of biologics, viz., by producing (i) bio-armoury comprising powerful antibiotics, antisera toxoids and vaccines to neutralise and eliminate a wide range of diseases, and (ii) bio-sensors for rapid detection, identification and neutralisation of biological warfare agents. This article elucidates some facets of biological warfare, legal protective strategies emphasised through international consultation, cooperation and adherence to the Biological and Toxin Weapons Convention, and discusses how biotechnology could be effectively used to strengthen countries' defence and combat the threat of biological warfare

Effect of gamma irradiation on DNA and <span style="font-size:14.0pt;font-family:HiddenHorzOCR;mso-bidi-font-family:HiddenHorzOCR">nucleohiston <i>in vitro </i>under <span style="font-size:14.0pt;font-family:"Times New Roman";mso-fareast-font-family: "Times New Roman";mso-ansi-language:EN-US;mso-fareast-language:EN-US; mso-bidi-language:AR-SA">physiological conditions</span></span>

178-182Pentose sugar and histones have been shown to deplete from DNA and nucleohistone (DNH) on gamma irradiation in a dose-dependent and biphasic manner in EDTA buffer while depletion of inorganic phosphorus (Pi) is a linear function of dose. In DNA, the depletion of sugar is more compared to that of Pi for 100 Gy. In DNH for 100 Gy the order of depletion is hitone > sugar> Pi .With 0.9% sodium chloride as solvent, for a total dose of 100 Gy, variation in the amount of sugar and protein depletion were observed when the dose rates were varied. From DNH at higher dose rate of radi ation (i.e. 2.92 Gy/sec), sugar depletion was 4 times and total histone depletion was 2.5 times than that for lower dose rate (i.e. 0.0156 Gy/sec). Pi depletion was found to be not dependent upon dose rate. Percentage hyperchromicity and hyperfluorophoricity for DNH decreased with increase in concentration both in 0.9% sodium chloride and standard saline citrate in the pH range 6.14 to 7.67, the values being higher in the former than in latter. DNA also showed consistent hyperchromicity with increase in radiation dose in EDTA buffer at ionic strength of 2.00.<span style="font-size: 14.0pt;font-family:HiddenHorzOCR;mso-bidi-font-family:HiddenHorzOCR"> </span

Role of topoisomerases in cytotoxicity induced by DNA ligand Hoechst-33342 and UV-C in a glioma cell line

313-323DNA ligand Hoechst-33342 significantly enhances UV induced cytotoxicity in human glioma cell lines (BMG-1 & U-87) with supra additive increase in cell death, cytogenetic damage, cell cycle delay, apoptosis and inhibition of PLDR. Cytotoxicity of Hoechst-33342 arises due to its interference in the breakage-rejoining reaction of DNA topoisomerases by stabilization of cleavable complexes. Since topoisomerases have also been implicated in the generation of potentially lethal DNA breaks by interaction with various types of DNA damage including UV induced DNA lesions, we investigated in present studies the role of functional topoisomerases in the synergistic cytotoxicity of Hoechst-33342 and UV in a human glioma cell line (BMG-1). Topoisomerase I activity analyzed by the plasmid relaxation assay, was significantly enhanced upon UV irradiation, implying a possible role of this enzyme in the processing of UV induced lesions. However, this increase in the activity was reduced by >50% in cells incubated with Hoechst-33342 for 1 hr prior to irradiation. Imunoflowcytometric analysis of the chromatin bound topoisomerases I and II levels (cleavable complex) using topoisomerases I and II anti-antibodies showed a good correlation between the induction of apoptosis by Hoechst-33342 and UV and enhancement in the level of topoisomerase II mediated cleavable complexes. Induction of apoptosis was associated with a decline in the level of Bcl2. Taken together; these studies show that supra additive cytotoxic effects of UV-C and Hoechst-33342 in BMG-1 cells are consequences of enhanced stabilization of topo II mediated cleavable complexes and alterations in specific signal transduction pathways of apoptosis, besides the inhibition of topoisomerase mediated repair processes