Environmental cancer in the Indian context

There is increasing global concern on the upward trend of cancer attributable to environmental causes. This has found articulate expression in the intensive action programme initiated in developed countries to carry out systematic epidemiological surveillance studies on environmental based cancer, to conduct both short-term and long-term studies on experimental animals on the mechanism of induction and to search for preventive measures. Of all environmental agents, chemicals which have been introduced by man have received the maximum attention on account of the fact that besides functioning per se as carcinogens, many chemicals can play roles of synergists, promotors, or procarcinogens. The total number of chemicals in wide use today will be more than a million but hardly a thousand of them has been subjected to the vigorous three animal safety evaluation according to Brigg. Developmental programmes initiated in post-independence India in the last three decades include industrialisation and modernisation of agriculture. So far as industrialisation is concerned, the major units have grown round certain urban centres or in settlements which have become identifiable pockets of high levels of air and water pollution. Data on air pollution inventory provided by NEERI and other agencies indicate a high content of polycyclic hydrocarbons, including 3,4-benzpyrenes especially in Bombay and Calcutta. The marginal health surveys conducted in these metropolitan cities have attempted only correlation between high incidence of respiratory disorders to particulate or gaseous pollutants. The modernisation of agriculture, particularly boosting of farm productivity, involves greater and greater use of past control chemicals and synthetic fertilisers. Chlorinated pesticides are also being used in massive quantities for controlling vector-borne epidemics. The evidence for an unusually high body burden of organochlorine pesticide residues in Indians has been documented. Many of them have been shown to be carcinogenic to experimental animals. Relatively high levels of residues of organochlorine have been detected in placentae, cord blood, and breast milk. The presence of high levels of suspected particulate matter (SPM) made up of industrially released pollutant in industrial areas, or air-borne pollens and microbial or fungal spores or the minute fugitive dust particles is also a problem of concern to us in this country. Besides health effects caused by them per se, they can act as nuclei for absorption of NO2 released from industrial activity or from bacterial reduction of nitrate fertilisers. Ideal matrices are formed for chain photochemical reaction triggered by solar or other cosmic irradiation giving rise to nitrosamines, free radicals, etc. Water used for potable purposes in some rural areas has been shown to contain relatively high nitrate and nitrite content. Occupational exposure to carcinogenic chemicals has also received some attention. Sporadic surveys have been conducted for the ulceration of the nose and septum in workers handling chromate salts (valency vi) or bladder tumors in anthracene dyes. Detailed analysis of environment related morbidity and mortality data has not yet been attempted to build models for the purpose of predictive epidemiology. Welders are exposed to fumes of heavy metals including those of chromium and nickel. The intake of nickel through leafy vegetables and hydrogenated vegetable oils has been considered as one possible source of bioaccumulation of this carcinogenic metal. In the absence of data banks or registry of reliable morbidity/mortality data in humans, the Industrial Toxicology Research Centre has made a partial survey of the dust load of lungs of food animals killed in abbatoirs in the industrial and mining areas of Bihar and West Bengal. Blocking of lymph nodes by dust has been observed in most of the animals and analysis of the dust collected from lung by X-ray fluorescence spectroscopy has revealed the presence of many toxic metals. The Outdoor Occupational Clinic run by the Industrial Toxicology Research Centre in ESI Hospital at Kanpur has recorded cases of skin allergy due to chromium

Effect of Ficus hispida L. on normal and dexamethasone suppressed wound healing

Ethanolic extract of roots of Ficus hispida was investigated in normal and dexamethasone depressed healing conditions, using incision, excision and dead space wound models in albino rats. The root extract of Ficus hispida has shown the maximum breaking strength compared to control group. The rate of epithelialization and wound contraction in excision model was better as compared to control groups. There was significant increase in granulation tissue weight and hydroxyproline content in dead space model compared to control group. The antihealing effect of dexamethasone was also reverted by the administration of ethanolic extract of Ficus hispida in all the wound models .The results indicated that the root extract of Ficus hispida has a significant wound healing activity and also promotes healing in dexamethasone depressed healing conditions.O extrato etanólico de raízes de Ficus hispida foi ensaiado em ratos albinos normais e em condições de cicatrização deprimida por dexametasona, utilizando modelos de ferida por incisão, excisão e de espaço morto. O extrato da raiz de Ficus hispida mostrou a força máxima de tensão comparativamente ao grupo controle. A velocidade de epitelização e de contração da ferida no modelo de excisão foi melhor do que a dos grupos controles. Houve aumento significativo no peso do tecido de granulação e no conteúdo de hidroxiprolina no modelo de espaço morto comparativamente ao grupo controle. O efeito anticicatrizante da dexametasona foi, também, revertido pela administração do extrato etanólico de Ficus hispida em todos os modelos de feridas. Os resultados indicaram que o extrato de Ficus hispida tem atividade cicatrizante em feridas e, também, promove a cicatrização em condições de depressão de cicatrização pela dexametasona

Differentiation of pathogenic amoebae: encystation and excystation ofacanthamoeba culbertsoni - a model

Differentiation into dormant cysts and vegetative trophozoites is an inherent character intimately associated with the life cycle and infectivity of pathogenic amoebae. In the case of human intestinal amoebiasis encystation and excystation are of immediate relevance to the process of transmission of the disease from healthy carriers to susceptible individuals. Using a pathogenic free living amoebaAcanthamoeba culbertsoni as a model, considerable progress has been achieved in understanding the mechanism and control of the process of differentiation. The turnover of the regulatory molecule cyclic 3: '5' adenosine monophosphate is responsible for triggering the process of encystation. Amoebae bind effector molecules such as biogenic amines to a membrane localized receptor which itself resembles the β-adrenergic receptor of mammalian organisms. The activation of adenylate cyclase or inhibition of cyclic AMP phosphodiesterase maintain the dynamic intracellular cyclic AMP. The cytosol fraction of amoebae has a cyclic AMP binding protein. During encystation, enzymes needed for synthesis of cellulose and glycoproteins are induced. Control is exercised at transcriptional level and the process is subject to catabolic repression. Excystation of mature amoebic cysts is mediated by glutamic acid and certain other amino acids by an as yet unelucidated mechanism. During excystation there is dormancy break, induction of deploymerizing enzymesviz. two proteases, a cellulase and a chitinase. The empty cysts or cyst walls are digested by these enzymes and their break down products are used for cellular growth. By invoking a flip-flop mechanism of repression and derepression some plausible explanation can be offered for the cascade of biochemical events that sets in when amoeba is 'turned on' to encystation or excystation

Uptake and release of bilirubin by skin

1. Skin epithelium of albino rat, mouse and guinea pig was shown to accumulate bilirubin from a medium containing free or bound bilirubin. 2. The Km values for bound bilirubin were 2.22×10-3, 1.33×10-3 and 9.5×10-4m for rat, mouse and guinea pig respectively and the corresponding Km values for free bilirubin were 5.2×10-4, 4.0×10-4, 1.8×10-4m; the Vmax. values of bound and free bilirubin were unchanged. 3. The uptake showed saturation kinetics. Bound bilirubin was released together with serum proteins. Free bilirubin bound to skin was not released into the medium. 4. Freezing and thawing of skin epithelium did not cause any significant lowering of the uptake of bilirubin but heat-denatured skin epidermis took up only 50% of the bound bilirubin or free bilirubin taken up by control unheated skin epithelium. 5. The uptake of free and bound bilirubin was prevented by HgCl2 but not by sodium arsenate, NaCN, NaF, cycloheximide, 2,4-dinitrophenol or iodoacetate. 6. Most of the free bilirubin was bound to the lipids or lipoprotein fraction of skin epithelium and could be extracted by solvents. 7. Rat skin showed the highest accumulation and efflux of bilirubin

Design of Packaging for Microballoon Actuators and Feasibility of their Integration within Aerodynamic Flight Vehicle

The microballoon actuators are used for the active flow control in turbulent boundary layer for aerodynamic control of flight vehicles. The packaging, interfacing, and integration of the microballoon actuators within the flight vehicle play a key role for functioning of the microballoon actuators during the flight conditions. This paper addresses the design and analysis of packaging and integration aspects and associated issues. The use of microballoon actuators on the control surfaces and nose cone of flight vehicles has the positive influence of delaying the flow separation from the aerodynamic surface. This results in enhancing aerodynamic effectiveness and lift as well as reduction of drag. A typical control surface is configured with eight microballoon actuators symmetric wrt the hinge line of the control surface and embedded within the control surface. Provision of the Pneumatic feed line system for inflation and deflation of the microballoons within the control surface has been made. The nose cone has been designed to have 32 such actuators at the circular periphery. The design is found to be completely feasible for the incorporation of microballoon actuators, both in the nose cone and in the control surface.Defence Science Journal, 2009, 59(5), pp.485-493, DOI:http://dx.doi.org/10.14429/dsj.59.154

Determination of leucine metabolism and protein turnover in sheep, using gas-liquid chromatography-mass spectrometry

1. Whole-body protein synthetic rates in non-pregnant ewes were determined by the continuous infusion of L-[15N]- and [1-13C]leucine and measuring the plasma enrichment of leucine, α-ketoisocaproate (α-KIC) and expired carbon dioxide by gas-liquid chromatography-mass spectrometry. 2. The mean whole-body protein synthesis estimated from plasma leucine flux corrected for oxidation was 5.38 (SE 0.54) g/kg per d. 3. Under the conditions of the present study leucine oxidation was 0.323 (SE 0.067) mmol/kg per d and accounted for 10.71 (SE 2.26) % of plasma [13C]leucine flux. Deamination of leucine was 0.55 (SE 0.035) mmol/kg per d and accounted for approximately 17% of plasma [15N]leucine flux. 4. The rate of a-KIC reamination to leucine, calculated by subtracting 13C flux from 15N flux, was 0.228 (SE 0.101) mmol/kg per d. 5. The rate of whole-body protein degradation was 4.49 (SE 0.54) g/kg per d and there was a net protein gain of 0.89 (SE 0.21) g/kg per d

Role of human skin in the photodecomposition of bilirubin

1. Human skin epithelium and human skin were found to absorb both free bilirubin and serum-bound bilirubin from an aqueous buffered medium. The serum-bound bilirubin thus absorbed was readily released when human skin epithelium or human skin were transferred to media containing no bilirubin. 2. The Km values for serum-bound bilirubin were 1.8×10-3m and 2.2×10-3m respectively for human skin epithelium and human skin; corresponding Km values for free bilirubin were 3.0×10-4m and 5×10-4m. The Vmax. for bound and free bilirubin was of the same magnitude, the apparent Vmax. being 1.0 and 1.66mmol/g of tissue for human skin epithelium and human skin respectively. 3. When human skin that had acquired a yellow tinge by absorbing bilirubin was incubated in a buffered medium and exposed to a mercury-vapour light, the yellow colour disappeared and decomposition products of bilirubin accumulated in the medium. 4. Experiments with [3H]bilirubin indicated that the pigment absorbed by skin was photo-oxidized to products that were soluble in water and the quantity and number of such products increased with the time of exposure of human skin to the light-source. Under similar conditions [3H]bilirubin alone in buffered medium was also oxidized and gave products which by paper chromatography appeared to be different from those released by human skin that had absorbed bilirubin. 5. The results suggest that by virtue of its large surface area human skin can act as a matrix for the degradative action of light on bilirubin

A systems approach to the control of chemical disasters

A systems approach is suggested for interlinking the three main components of a chemical accident: the event, the target and the effects. Such an approach helps in identifying information gaps vitally needed for establishing cause-effect relationship, forassessing risks from continuing or long term effects and for developing preventive measures for reducing injury from chemical accidents. Feasible classification modes of accidents such as during production, processing, distribution, transport and dismissal can be conveniently incorporated. Contingency and rehabilitation plans can be put in proper perspective so that the support infrastructure needed can be established and updated. Areas of research to be pursued on proirity basis to get feedback on methods for assessing risks can be delineated along with programmes for the development of the required technical manpower