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Biomedical subjects

L Fishbein

Publications and source records attributed to L Fishbein.

At least 37 records · Page 2Linked to original sources
PubMed1987

Health-risk estimates for 2,3,7,8-tetrachloro-dibenzodioxin: an overview.

As has been abundantly noted by many investigators, the paucity of definitive knowledge of metabolism, pharmacokinetics and pathogenesis of the chlorinated dioxins, principally 2,3,7,8-TCDD, in human populations continues to severely limit our ability to evaluate the scope of the chronic and delayed effects of exposure to these agents. The marked qualitative and quantitative differences in the response of animals to TCDD plus the inability to validate a number of the critical assumptions and mathematical models relative to risk assessment make the extrapolation of data from intact animals to man particularly uncertain. Hence, it is vital to vigorously pursue the elaboration of the mechanism of action of TCDD at the molecular level. This should greatly contribute to our fundamental understanding of this agent and the potential danger that it may pose for man.

Accidents, Occupational↗
PubMed1987

Perspectives on occupational exposure to antineoplastic drugs.

This review has attempted to focus on the salient features of the potential risks of occupational exposure to the major antineoplastic agents that have broad utility in cancer chemotherapy, as well as in the treatment of a spectrum of refractory non-malignant conditions. An initial focus centered about the classes (primarily alkylating agents, antimitotics, antibiotics, and antimetabolites), types of action and their carcinogenicity, genotoxicity, and reproductive effects exhibited by many of these agents in animals and treated patients. Nurses, pharmacists, and oncologists are the principal individuals with a potential risk to these agents primarily during the preparation and administration of these agents. Although the number at potential risk are not known precisely, they are believed to be relatively small in the aggregate, perhaps numbering several thousand. The measurement of exposure has generally been attempted on a relatively small number of nurses and pharmacists by biological monitoring employing urinary mutagenicity assays and cytogenetic analysis with conflicting results. The levels of exposure currently found are low compared to the therapeutic doses employed and are probably much lower than that which may have occurred earlier before the employment of vertical laminar flow hoods and the more recent implementation of guidelines and/or recommendations. The long-term effects of exposure to occupational personnel at potential risk of exposure to chemotherapeutic agents and waste are not known. Although studies to date have failed to show conclusively that nurses and pharmacists are at risk to the carcinogenic, genotoxic and reproductive effects of these agents, prudence would dictate that every effort be taken to minimize their exposure during the handling and disposal of antineoplastic drugs.

Antineoplastic Agents↗
PubMed1986

A toxicological review of beta-adrenergic blockers.

The use of various beta-adrenergic blockers has become extensive as they have been found to be efficacious in the treatment of a number of cardiovascular problems including cardiac arrhythmias, angina pectoris, and hypertension. The widespread and chronic use of these drugs has generated a concern for their potential chronic toxicity. Eighteen beta-adrenergic blockers have been reviewed and the available literature pertaining to their potential carcinogenicity, mutagenicity, and teratogenicity has been summarized and compared.

Acebutolol↗
PubMed1986

An IARC Manual series aimed at assisting cancer epidemiology and prevention. "Environmental carcinogens: selected methods of analysis".

Since 1975, the IARC has been preparing a series of volumes entitled "Environmental Carcinogens: Selected Methods of Analysis" (IARC Manual series) of which the purposes are to assist analysts, epidemiologists and regulatory authorities in planning or performing exposure measurements that are truly comparable between different studies. The Manual series provides expert information within each volume on multi-media sampling, methods of analyses and some background of epidemiology, metabolism, use/occurrence for a group of known or suspect carcinogens. So far, eleven volumes have been published or are in preparation on the following subjects: N-nitrosamines, vinyl chloride, PAH, aromatic amines, mycotoxins, N-nitroso compounds, volatile halogenated hydrocarbons, metals, passive smoking, benzene and alkylated benzenes, dioxins, PCDFs and PCBs. The presentation will discuss needs and priorities for use of analytical chemistry in estimating exposures of apparently greatest relevance to cancer causation, i.e. the approach to developing this series. Indications from epidemiology, evaluations of carcinogenic risk to humans, and recent developments in total exposure assessment are that new methods and matrices need more emphasis, e.g. as with biochemical dosimetry, exhaled breath, and in indoor air.

Carcinogens, Environmental↗
PubMed1986

Contribution of organic particulates to respiratory cancer.

This paper presents some of the issues that remain to be resolved in order to assess the risk of cancer related to exposure to organic particulates. Most reviews of the effects of organic particulates from the outdoor environment on the risk of lung cancer show that this source seems to play a minor role. However, as fuel use and chemical composition of air pollutants change, the contribution of outdoor pollution as a cause of cancer may also change. Indoor air pollution is a more important source of exposure to organic particulates than is outdoor exposure. Although there is clear evidence that in occupational settings organic particulates cause human cancer, there has been almost no study of exposure to these types of particulates within indoor settings. Previous research has focused on cigarette smoke as the major indoor pollutant, but more specific characterization of contaminants in both the workplace and the home is required. The health effects of the higher levels of some of these contaminants in the workplace should be evaluated and the results extrapolated to populations exposed to lower levels in the home. Extensive research is needed to characterize organic particulate mixtures appropriately and test them for carcinogenicity. Studies on the health risks of nitropolynuclear aromatic hydrocarbons and polychlorinated dibenzodioxins and dibenzofurans are reviewed, but their contribution to the overall burden of respiratory cancer in humans cannot be estimated at this time. Characterization of mixtures, assessment of exposures, and linkage of exposures to health effects are the objectives of the recommendations proposed for further research.

Air Pollutants↗
PubMed1986

Perspectives in metal carcinogenesis. I. Selenium.

This review has focused primarily on the sources of exposure to selenium and its role as an antioxidant as well as its anticarcinogenic and antimutagenic properties. Selenium is an essential trace element and a constituent of glutathione peroxidase in human erythrocytes. Numerous studies with animals have demonstrated that it is a potent inhibitor of virally- and chemically-induced tumorigenesis when administered continuously in a variety of tumor systems (predominantly in the skin, liver, colon, and mammary gland). The mechanisms by which selenium inhibits tumorigenesis is not definitely known. Several epidemiological studies have demonstrated statistically significant inverse associations between human cancer mortalities in different populations. In these studies, the regional availabilities of selenium were measured via a variety of means, including blood selenium levels, the concentration of selenium in grains and forage crops or from calculated apparent selenium intake estimated from food consumption and consumption data. These animal and human studies demonstrating inverse associations between tumorigenesis and selenium levels have led to suggestions that selenium be considered a prophylactic agent in the chemoprevention of tumorigenesis. It would appear prudent to avoid the unnecessary supplementation of normal diets with selenium.

Air Pollutants↗
PubMed1985

An overview of environmental and toxicological aspects of aromatic hydrocarbons. III. Xylene.

The commercial product "mixed xylenes" (a technical product generally containing approximately 40% m-xylene and 20% each of o-xylene, p-xylene and ethylbenzene, as well as small quantities of toluene) analogously to toluene is an agent of major chemical and occupational significance. It is produced in very large quantities and is extensively employed in a broad spectrum of applications, primarily as a solvent for which its use is increasing as a "safe" replacement for benzene, and in gasoline as part of the BTX component (benzene-toluene-xylene); xylenes are also frequently used in the rubber industry with other solvents such as toluene and benzene. As individual isomers they are extensively employed in the synthesis of synthetic agents, for example phthalic acid, isophthalic acid, terephthalic acid and dimethylterephthalate, which have very broad applications in the further preparation of phthalate ester plasticizers and components of polyester fiber, film and fabricated items. There is a broad potential for exposure both to industrial workers in the production and use of the xylenes and to the general public (via vehicle exhausts, consumer products, etc). Compared with benzene and toluene, very much less is known of the human health hazards, particularly the chronic effects of xylenes, either as mixed xylenes, as individual isomers or in admixture with other alkylbenzenes. It is of importance to note that coal-based solvents (e.g., xylene) have been suggested to be possible potent lymphocytic leukemogens, such as benzene, in a limited study of the relationship between lymphocytic leukemia and exposures to benzene and other solvents in the rubber industry. Available animal data on the carcinogenicity of xylene(s) are inadequate to permit an evaluation. Mixed xylenes are currently being investigated in a chronic bioassay by the National Toxicology Program. In limited studies thus far, the individual isomers have not been found genotoxic when tested in a number of short-term tests.

Biological Transport↗
PubMed1985

An overview of environmental and toxicological aspects of aromatic hydrocarbons. II. Toluene.

The salient aspects of the exposure to toluene were reviewed via an initial examination of the production, use, occurrence and disposition of toluene, as well as populations at potential risk. Special note should be taken as to the increasing use of toluene as a "safe" replacement for benzene in solvent applications and its increasing use in many consumer products. There is a broad potential for exposure by industrial workers and the general public (via vehicle exhausts and consumer products). The effects on humans and animals as well as the genetic effects of toluene were also reviewed following an initial consideration for its absorption and elimination. The narcotic and neurotoxic properties of toluene represent the main recognized health hazards to humans.

Animals↗
PubMed1985

An overview of environmental and toxicological aspects of aromatic hydrocarbons. IV. Ethylbenzene.

The solvent aspects of exposure to ethylbenzene are reviewed via an initial examination of the production, use, occurrence, and disposition of ethylbenzene as well as populations potentially at risk. While occupational exposure to ethylbenzene during its production and subsequent conversion to styrene is believed to be minimal, the broader occupational exposure to ethylbenzene during the production and use of 'mixed xylenes' is another area of concern. The general public can be exposed to ethylbenzene in ambient air as a result of its occurrence in motor vehicle exhaust. Additional exposure can arise in indoor environments, mostly from passive exposure to cigarette smoke. Ethylbenzene is primarily an irritant to the skin and mucous membranes and possesses narcotic properties at high concentrations.

Animals↗
PubMed1984

An overview of environmental and toxicological aspects of aromatic hydrocarbons. I. Benzene.

The salient aspects of the exposure to benzene were reviewed via an initial examination of the production, use, occurrence and dispersion of benzene, as well as populations at potential risk. Although benzene is ubiquitous in the environment, the major source of benzene in ambient air is via its use and occurrence in gasolines and subsequent emissions. Exposure to benzene in the general population is suggested to be several orders of magnitude less than to occupational cohorts. Levels of benzene exposure in the workplace have dropped considerably from that which was manifest in the 1940-1950 decade (e.g., 10-100 ppm) also due to the decreasing use of benzene as a solvent. The effects on humans and animals as well as genetic effects of benzene were also reviewed following an initial consideration of its absorption and elimination. The toxic effects on the hemopoietic system were cited with special consideration to the long-term exposure to benzene and the occurrence of leukemia.

Animals↗
PubMed1984

Overview of analysis of carcinogenic and/or mutagenic metals in biological and environmental samples. I. Arsenic, beryllium, cadmium, chromium and selenium.

One of the most dangerous and pernicious forms of pollution arises from the potential mobilization of a spectrum of toxic trace metals and metalloids in our environment. Among the most important elements in this regard are arsenic, beryllium, cadmium, chromium and selenium whose adverse toxic effects are now well recognized including their carcinogenicity and/or mutagenicity. These agents (and their derivatives) can be widely dispersed throughout the environment as a result of fossil fuel combustion, industrial and agricultural processes and natural processes. The trend for the immediate future appears to be of greater exposure to these metals not only as a result of generally increased usage patterns but also because of prospective enhanced use of fossil fuels for space heating and electricity generation. In order to more readily evaluate trends of human exposure as well as the toxicity, bioavailability, bioaccumulation and transport of these elements, sensitive analytical procedures are required for the determination of their various oxidation states (as well as their organic derivatives) in complex matrices such as those found in both environmental and biological samples. Hence, the principal objective of this overview is to highlight the more recent trends and state-of-the-art methodologies for the determination of arsenic, beryllium, cadmium, chromium and selenium (in their various forms) in environmental compartments such as air, water, soil and in human tissues (primarily blood, urine, and milk). Techniques to be discussed primarily include atomic absorption spectrometry, neutron activation analysis, gas chromatography, differential pulse polarography and electrochemical analysis. The importance of quality control and differentiation according to speciation will also be stressed.

Air↗
PubMed1984

Toxicity of the components of poly(vinylchloride) polymers additives.

The salient features of the toxicity of a number of additives used in polyvinyl chloride polymers were reviewed with primary emphasis on the toxicity of plasticizers (e.g., diethylhexyl phthalate and its metabolites, butylbenzylphthalate and di(2-ethylhexyl)adipate), heat stabilizers (e.g., organotin and lead stabilizers), blowing agents (e.g., azodicarbonamide), free-radical initiators (e.g., benzoylperoxide, lauroyl peroxide, ter.butylhydroperoxide and di-tert.butylperoxide, and flame retardants (e.g., decabromodiphenyl oxide). The paucity of toxicity data on the vast majority of PVC additives should be stressed.

Animals↗
PubMed1984

Toxicity of the components of styrene polymers: polystyrene, acrylonitrile-butadiene-styrene (ABS) and styrene-butadiene-rubber (SBR). Reactants and additives.

The toxicity of the components of styrene polymers, e.g., polystyrene, ABS and SBR, were reviewed with primary focus on the reactive monomers (except styrene) (e.g., acrylonitrile, butadiene) as well as on impurities and solvents such as benzene, hexane and methylethyl ketone, and additives such as phenyl-2-naphthylamine, di-n-butyl phthalate, and a number of peroxide initiators and flame retardants (e.g., 2,3-dibromopropanol, decadibromodiphenyl oxide and antimony trioxide). It is stressed that toxicity data are generally lacking for the majority of additives employed in the production of styrene polymers. Information is also lacking as to the numbers of individuals at potential risk and the extent of their exposure to the large number of additives employed.

1-Naphthylamine↗
PubMed1984

Additives in synthetic polymers: an overview.

The 14 major classes of additives in plastics, e.g., plasticizers, flame retardants, heat stabilizers, antioxidants, UV absorbers, foaming agents, initiators, lubricants, antistatic agents, curing agents, colorants, fillers and reinforcements, solvents, and optical brighteners were reviewed from a primary consideration of their structural chemical classes, areas of application as well as their production volumes and future use trends. The number of possible combinations of plastics additives that can be employed are staggering. In most cases, little is known of their toxicological properties and in many cases their identity is not commonly known. It should also be noted that many new additives of new generic types in each of the above classes are being developed and introduced into the market yearly as well as new technology in polymer production, e.g., increasing use of additive polymers for PVC.

Chemical Industry↗
PubMed1983

Chemicals used in the rubber industry. An overview.

Hundreds of chemicals illustrative of many structural and use categories are employed in the rubber industry. The present overview has centered on the structural features of a number of compounds representative of several select use categories, eg, vulcanizing agents, accelerators, antioxidants, antiozonants, and blowing agents, with focus on the nature of their impurities, their chemical degradation, and by-products, as well as on those chemicals that can be converted to N-nitrosamines.

Carcinogens↗