Volume

Volume 37 - Year :1987

(45)

Issue 2-April 1987

(14)

	An Overview of the Health Hazards Due to Toxic Exposure in the Indian Work Environment Author : Ramaswamy, S.S. Source : Defence Science Journal ; Vol:37(2) ; 1987 ; pp 113-131 Subject : 615.9 Toxicology;615 Pharmacology Keywords : Toxicology ;Organophosphorus pesticides Abstract : Since independence, there has been a phenomenal growth in the chemical industry, the number of units rising from 98 in 1947 to 964 in 1953 and 4364 in 1976. With the national demands ever growing , this trend of growth in chemical industry will continue in future also. The chemical units handle numerous toxic chemicals such as asbestos, benzene, carbon disulphide, carcinogenic dye intermediates, lead, manganese, organophosphorus pesticides, phosgene, vinyl chloride etc. Being aware of the potential health hazards arising out of exposure to these toxic chemicals necessary safeguards against health hazards have been incorporated in the Factories Act 1948. With nearly 100,000 tonnes of asbestos, over 100,000 tonnes of benzene, and considerably large quantities of other toxic chemicals being handled in the country, understandably, the random studies and surveys by research agencies have revealed the incidence of definite asbestosis (7 per cent), benzene intoxication in alkaloid extraction units (44.8 per cent), lead poisoning in storage battery units (10.6 per cent), carbon disulphide poisoning in viscose rayon units (20 per cent), mercury poisoning and intoxication in chloroalkali units (22.7 per cent), manganese poisoning in ferromanganese units (24 per cent), silicosis among slate pencil workers (54.7 per cent) etc. Albeit such a condition, the cases documented in official reports are very few. Even the scattered studies by research institution in occupational health cannot be pooled to evolve a national picture, since, quite often there is no standardised approach in the studies undertaken by different institutions. After discussing the findings of studies on various toxic chemicals and substances, the paper enumerates the present deficiencies in the current studies and suggest steps for obtaining comprehensive information on health hazards.
	Drug Xenobiotic Metabolism Disposition and Toxicity in Malnutrition Author : krishnaswamy, Kamala Source : Defence Science Journal ; Vol:37(2) ; 1987 ; pp 133-142 Subject : 615.9 Toxicology;615 Pharmacology Keywords : Bio transformation ;Protein binding distribution Abstract : "The role of malnutrition and diet in general on bioprocess, which govern the fate of drug/xenobiotic in the body only just beginning to be understood. Absorption, protein binding distribution, bio-transformation and renal elimination of xenobiotics/drugs are all affected by altered states of nutrition. As such, evaluation of nutritional status is highly relevant prior to prolonged drug thereby especially with drugs having narrow safety margin. "
	Toxicological Considerations in the Use of Consumer Products Author : Menon, K.K.G. ;Mulky, M.J.;Cherian, K.M. Source : Defence Science Journal ; Vol:37(2) ; 1987 ; pp 143-159 Subject : 615 Pharmacology;615.9 Toxicology Keywords : Carcinogenicity tests ;Carcinogens Abstract : Reviews different methods of screening carcinogens by using in vitro and in vivo carcinogenicity tests. Elaborates on naturally occurring carcinogens in food materials, in working environment and consumer products like dyes. The effects of various consumer products like oils, fats, protein foods and non-metallic and metallic substances used in consumer products have been reviewed. The long-term effects on skin such as dermatitis and irritation due to various chemicals used in consumer products have been elucidated. The effects of tetragons and hazards due to packing materials have also been examined. Finally, the need for safety in raw materials has also been emphasised as important for elimination of toxic effects.
	Toxicology of Processed and Packaged Foods Author : Sharma, T.R. ;Srivatsa, A.N. Source : Defence Science Journal ; Vol:37(2) ; 1987 ; pp 161-172 Subject : 615.9 Toxicology;615 Pharmacology Keywords : Health hazards ;Pesticides;Antioxidants Abstract : Modern food production, processing and preservation use a large number of additives at various stages. These include food sweetners, preservatives, colours, antioxidants and pesticides. In addition , the foods come in contact with packaging materials which by themselves contain a large number of additives. Some of these are potential sources of hazards to consumers. This paper is a review of investigations which have been carried out on some of the additives, the migration of additives from packing systems and naturally occurring toxic substances as possible health hazards.
	Toxicology of Biomedical Polymers Author : Fernandez, A.C. ;Vedanarayanan, P.V. Source : Defence Science Journal ; Vol:37(2) ; 1987 ; pp 173-183 Subject : 615 Pharmacology;615.9 Toxicology Keywords : Polymer science ;Medical science Abstract : This paper deals with the various types of polymers, used in the fabrication of medical devices, their diversity of applications and toxic hazards which may arise out of their application. The potential toxicity of monomers and the various additives used in the manufacture of biomedical polymers have been discussed along with hazards which may arise out of processing of devices such as sterilization. The importance of quality control and stringent toxicity evaluation methods have been emphasised since in our country, at present, there are no regulations covering the manufacturing and marketing of medical devices. Finally the question of the general and subtle long term systemic toxicity of biomedical polymers have been brought to attention with the suggestion that this question needs to be resolved permanently by appropriate studies.
	Aerobiology and Spread of Microbial Diseases Author : Roffey, Roger ;Bovallius, Ake Source : Defence Science Journal ; Vol:37(2) ; 1987 ; pp 185-204 Subject : 579 MicroBiology Keywords : Occupational hazard ;Micro organisms Abstract : The different steps in spread of micro-organisms through the atmosphere causing diseases have been detailed. Case studies of a variety of disease outbursts have been correlated with the sources and spread of causative agents. These micro-organisms also flourish in certain work environments causing an occupational hazard.
	Toxicological Significance of Silicon Protein Interaction Author : Viswanathan, P.N. ;Jaffery, Farhat N. Source : Defence Science Journal ; Vol:37(2) ; 1987 ; pp 221-233 Subject : 615.9 Toxicology;615 Pharmacology Keywords : Cardiovascular diseases ;BSA Si complex ;Pollutants;Molecular mechanism Abstract : In order to understand the molecular mechanism of the toxicity of Si containing particulate air pollutants, the interaction between silicate anion and proteins was studied. On the basis of molecular sieving profile, the presence of a protein fraction capable of binding silicic acid was detected in rat lung and serum. The binding is firm being able to withstand dialysis, Si-binding by Bovine Serum Albumin (BSA) follows stoichiometric principles indicating true chemical reaction in terms of effects of pH, temperature and period of incubation. Fluorescence spectrum of the BSA-Si complex decreased with an increase in Si concentration. Effect of Si-binding on trypsin activity against albumin showed that proteins other than albumin could also interact with Si-trypsin containing silica showed distinctly low catalytic activity against native BSA. When both the substrate and enzyme contained bound Si, the activity further reduced by 36 per cent as compared to both pure trypsin and pure BSA, clearly indicating that binding of Si with substrate or enzyme proteins can adversely effect the biological activity. Complexing with proteins is likely to play a role in pathogenesis of pneumoconiosis, elimination of dusts, formation of silicate stones in plants and animals, and possibly in the reported role of Si in nutrition, cardiovascular diseases and ageing.
	Immunotoxicology: Modulation of the Immune System by Xenobiotics Author : Nagarkatti, Mitzi ;Nagarkatti, Prakash S. Source : Defence Science Journal ; Vol:37(2) ; 1987 ; pp 235-244 Subject : 61 Medical Sciences Keywords : Immunotoxicological screening ;Immune system;Immunity Abstract : Starting with a definition of immunity, this review describes general mechanisms by which immune system is modulated and details several immunotoxicological screening methods to assess the immumologic and host resistance alterations following chemical exposure. Among a variety of immuno toxic compounds known, only four representative compounds namely o-chloro benzylidine malonoitrile (CS), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), chloroquine 1,3-bis (2-chloroethyl) 1-nitrosourea (BCNU) have been chosen for an elaborate discussion.
	Immunomodulation of Host as a Predictive Bio Indicator of Toxicity in the Mammalian System Author : Singh, K.P. ;Saxena, A.K.;Ray, P.K. Source : Defence Science Journal ; Vol:37(2) ; 1987 ; pp 245-255 Subject : 61 Medical Sciences Keywords : Micro organisms ;Immune system;Immune Abstract : Immune system is complex in nature, consisting of multi organ involvement in its activity. It is one of the most sensitive systems in the body. Any foreign material i.e. chemicals, drugs and micro-organisms, if enters in the body, may produce alteration in the function of the immune system. Only recently information has been generated that many environmental chemicals and drugs can produce modulation of the immune system in even low doses of exposure and for a short period. Some chemicals in low doses produce severe immunotoxicity well before producing any sign of overt toxicity to the other system. This can be only predicted by using immunotoxicological tests. The chemicals that enhance the immune response may predispose the host to auto-immune disease or lymphoreticular disorders resulting in allergic or hypersensitivity reactions. On the other hand, the chemicals that suppress immunity may sufficiently disrupt the immunoregulatory network, resulting in increased susceptibility to infection or to develop cancer. In the recent past toxicological assessments were done by using lethal dose (50%) evaluation, use of biochemical and pathological examination of different organs, which gives information only about the cell number or degree of cellularity. The early effect of chemicals on the cell function may be missing in that type of study. Currently, the inclusion of immunological assessment parameters in toxicity evaluation of chemicals have made it possible to test the toxicity at the cellular level. It has been well known that many of the environment chemicals at very low doses can modulate immune system without producing any clinical sign or symptoms of the disease or disorders. It is of importance that assessment of immunomodulation can be used as a sensitive bio-indicator for predicting the toxicity casused by environmental chemicals, since immunotoxicity can be determined with much smaller dosages of chemicals than is needed for toxicity evaluation of chemicals using animals.
	Environment in Submarine Compartments Author : Rao, M.V.R. Koteswara ;Shrivastava, Anil K. Source : Defence Science Journal ; Vol:37(2) ; 1987 ; pp 257-267 Subject : 61 Medical Sciences Keywords : Air pollution ;Air pollutants;Physiological stress Abstract : The crew operating in the confined environment of a submarine are subjected to discomfort as a result of physiological stress caused by toxic substances which are generated due to engineering, operational and other human activites. The physiological problems of men under prolonged confinement in a submarine have been reviewed. Data on air pollutants monitored during 'cruise' and 'at rest' conditions inside a submarine are given. Threshold limit value(TLV) of trace substances in the confined environment has been discussed. The merits of air purification and air revitalization system currently employed for control of air pollution have been brought out.
	Health Effects and Toxicity of Phosgene: Scientific Review Author : Mehlman, M.A. Source : Defence Science Journal ; Vol:37(2) ; 1987 ; pp 269-279 Subject : 615.9 Toxicology;615 Pharmacology Keywords : Pathology ;Phosgene Abstract : The chemistry and toxicology of phosgene are reviewed at length. Manufacture, physical and chemical properties and industrial application of this important chemical intermediate are presented. Both acute and chronic exposure studies on animals and some human exposure data are also discussed. Pathology of phosgene poisoning and reliable therapeutic measures are critically examined.
	Chemistry and Toxicity of Tear Gases Author : Pravin Kumar ;Malhotra, R.C. Source : Defence Science Journal ; Vol:37(2) ; 1987 ; pp 281-296 Subject : 615.9 Toxicology;615 Pharmacology Keywords : Irritants ;Gases Abstract : The article presents a historical background on the use of tear gases in war and civilian riot control activity. The classification of chemical compounds used as irritants, and their structure-activity relationship established through different studies has been examined. A review of toxic effects which is different from irritancy of Adamsite, omega-chloroacetophenorie(CN), o-chlorobenzylidene malononitrile (CS) and Dibenz (b,f),[1,4}-oxazepine(CR) has been presented.
	Generation of Toxicological Data on Chemicals in the U.S.A. Author : Upton, A.C. ;Nelson, N. Source : Defence Science Journal ; Vol:37(2) ; 1987 ; pp 85-97 Subject : 615.9 Toxicology;615 Pharmacology Keywords : Carcinogenicity tests ;Toxicological testing Abstract : The paper reviews the current trends of toxicological testing of chemicals in the U.S.A. and the methods of data generation for risk assessment and regulatory purpose. The recent survey conducted by NAS/NRC revealed that only a small fraction of widely used chemicals have been tested toxicologically. In spite of developments in short-term toxicological tests, using non-mammalian test species continue to be indispensable. In evaluating carcinogenicity tests, the current approach is generally based on the assumption that there is not threshold. Under the regulation of the Toxic Substances Act 1977(U.S.A.) the responsibility of providing toxicological data lies with the manufacturer. The National Toxicology programmme emerged as a new governmental agency for toxicological evaluation since 1978 integrating a number of pre-existing testing activities in U.S.A. A number of private testing laborites which can provide test data on contract basis also have come into existence in U.S.A. The guidelines published for risk assessment by the Environmental Protection Agency is expected to provide standards for the conduct of toxicological tests used for regulatory purposes. The newly formed Broad on Environmental Studies Toxicology reviews and evaluates the toxicological issues.
	Conceptual Approaches to Alternate Methods in Toxicological Testing Author : Rowan, Andrew N. ;Goldberg, Alan M. Source : Defence Science Journal ; Vol:37(2) ; 1987 ; pp 99-112 Subject : 615.9 Toxicology Keywords : Cell biology ;Computer modelling;Toxicity testing Abstract : Due to public pressure in vivo methods of toxicity testing is being attempted to be replaced by in vitro methods, such as cell and organ culture, computer modelling and modified LD/sub 50/ tests using lesser number of animals. Specifically in the case of Draize eye irritancy test using rabbits, a number of refinements have been incorporated by different workers, mainly use of a local anaesthetic which will reduce animal distress without vitiating the test results. The author recommends exploration of new avenues for testing based on the advances in cell biology.