Showing papers in "Environmental Health Perspectives in 1980"

Pyrethrum flowers and pyrethroid insecticides.

Abstract: The natural pyrethrins from the daisy-like flower, Tanacetum or Chrysanthemum cinerariifolium, are nonpersistent insecticides of low toxicity to mammals. Synthetic analogs or pyrethroids, evolved from the natural compounds by successive isosteric modifications, are more potent and stable and are the newest important class of crop protection chemicals. They retain many of the favorable properties of the pyrethrins.

Relationship between biotransformation and the toxicity and fate of xenobiotic chemicals in fish.

Abstract: Many of the biotransformation reactions which have been described for xenobiotic substances in mammals have been demonstrated in fish in both in vitro and in vivo experiments. Several of these biotransformation reactions have been shown to occur in fish at rates which are sufficient to have significant effects on the toxicity and residue dynamics of selected chemicals. Inhibition of these reactions can lead to increased toxicity and bioaccumulation factors for certain chemicals. Several classes of compounds, including some polychlorinated biphenyls, are metabolized slowly, and their disposition in fish may not be influenced to any great extent by biotransformation. Metabolites of compounds which are biotransformed rapidly may appear in certain fish tissues, and in many instances these are not accounted for by conventional residue analysis methods. Microsomal mixed-function oxidases in several species of fish have been demonstrated to be induced by specific polycyclic aromatic hydrocarbons and by exposure of fish to crude oil. Induction of these enzymes in fish can result in both qualitative and quantitative differences in the metabolic disposition of xenobiotics to which fish are exposed.

Interaction between environmental pollutants and respiratory infections.

Abstract: The major aspects that must be considered in studies of the health effects of environmental pollutants are: the direct damage due to the exposure, the role of pre-existing disease, and effects of the exposure on the response to secondary stresses. In experimental studies at concentrations of air pollutants found in urban environments frank toxicological responses are rarely observed. However, exposure to a secondary stress, i.e., respiratory challenge with infectious bacteria, can exacerbate the response of the experimental host. Changes in the resistance to respiratory infections provide a highly sensitive experimental animal model system, which is increasingly used in studies of health effects of air pollutants. This model indicates the impairment of the basic defense mechanisms of the respiratory system by the combined exposure to low concentrations of pollutants and the superimposed bacterial infection. Changes in the resistance to respiratory infections were studied in various species of laboratory animals. S. pyogenes and K. pneumoniae are the bacteria of choice to induce the pulmonary infection. Included in the studies are short-term single and multiple exposures as well as long-term exposures to gaseous pollutants such as O3 and NO2 and particulate pollutants such as sulfates and nitrates. Changes in the resistance are measuredmore » as excess mortalities and reduced survival time as compared to those in infected animals not exposed to the pollutants. Other parameters measured ranged from changes in the immune response to changes in retention rates of bacteria in lungs.« less

Long-term hazards of polychlorinated dibenzodioxins and polychlorinated dibenzofurans.

Abstract: During January 10-11, 1978 in Lyon, France, a joint National Institute of Environmental Health Sciences/International Agency for Research on Cancer ad hoc Working Group considered and discussed the feasibility of coordinating epidemiological studies on the long-term hazards associated with the chlorinated dibenzo-p-dioxins and chlorinated dibenzofurans (PCDDs and and PCDFs). Nineteen invited scientists from eight countries presented introductory working papers summarizing the most up-to-date and relevant information available from their individual programs. This report represents the collective views and scientific opinions of the Working Group. The greater part of this document comprises epidemiological studies related to episodes of human exposures. The review begins with a brief section concerning possible routes of human exposure, an overview of the pertinent chemical characteristics, and the salient toxicological properties of the structurally similar PCDDs/PCDFs. The Working Group report ends with recommendations for future activities.

Negative ions of polyatomic molecules

Abstract: In this paper general concepts relating to, and recent advances in, the study of negative ions of polyatomic molecules area discussed with emphasis on halocarbons. The topics dealt with in the paper are as follows: basic electron attachment processes, modes of electron capture by molecules, short-lived transient negative ions, dissociative electron attachment to ground-state molecules and to "hot" molecules (effects of temperature on electron attachment), parent negative ions, effect of density, nature, and state of the medium on electron attachment, electron attachment to electronically excited molecules, the binding of attached electrons to molecules ("electron affinity"), and the basic and the applied significance of negative-ion studies.

Epidemiology of Asbestos-Related Diseases

Abstract: This paper is intended to give the reader an overview of the epidemiology of asbestos-related diseases and is restricted to primarily occupational exposure studies. However, some mention of nonoccu...

Macrophage damage in relation to the pathogenesis of lung diseases.

Abstract: Pulmonary macrophages are important since their migratory patterns and behavior are often pivotal events in the pathogenesis of pulmonary disease. Alveolar macrophages act to decrease the probabili...

Lymphatic removal of fluids and particles in the mammalian lung.

Abstract: The structure and distribution of pulmonary lymphatics and their permeability to fluids and particulate materials have been investigated in the lungs of rats following fixation by combined intratra

Cellular effects of asbestos and other fibers: correlations with in vivo induction of pleural sarcoma.

Abstract: The phenomenon of fiber-induced cytotoxicity to P388D1 macrophagelike cells has been demonstrated to parallel (thus far without exception) the probability that the fiber will induce a pleural sarcoma (mesothelioma) in rats This startling parallel in both cases seems to be essentially independent of the chemical nature of the fiber and correlates best with the presence of fibers greater than 8 micrometers in length and fibers with diameters in the range 05 to 10 micrometer (Stanton Hypothesis) In both systems evidence has been produced which cast strong doubts on any role played by absorbed (or adherent) impurities The existence of multiple physical forms of the same chemical moiety (aluminum oxide, dihydroxy-sodium aluminum carbonate, borosilicate glass, etc,) provides additional test material for the chemical independence corollary The similar, cytotoxic or sarcomatogenous behavior of chemically different materials (eg amosite, chrysotile, aluminum oxide) exhibits the necessary converse argument As long as the fiber size-shape dependency effect was limited to whole animal phenomena, such as tumor induction, one could make implicitly what were essentially statistical or probabilistic inferences involving transport and/or distribution of fibers to account for the physical effect The demonstration of strict parallelism at the cellular level in vitro suggests the possibility that in the case of durable fiber toxicology we are dealing with a form of cell-solid interaction in which physical properties for which we have as yet no known receptors play a prominent role

Response of a phagocyte cell system to products of macrophage breakdown as a probable mechanism of alveolar phagocytosis adaptation to deposition of particles of different cytotoxicity.

Abstract: The adaptation of the alveolar phagocytosis response to the quantitative and qualitative features of dust deposited during inhalation consists not only in enhanced recruitment of alveolar macrophages (AM), but also in adding a more or less pronounced neutrophil leukocyte (NL) recruitment as an auxiliary participant of particle clearance. The NL contribution to clearance is especially typical for response to cytotoxic particles (quartz, in particular). An important feature of the adaptation considered is the limitation of the number of AM and NL recruited when an efficient clearance can be achieved by a lesser number of cells due to increased AM reistance to the damaging actin of phagocytized particles. The main mechanism providing the adequacy of the alveolar phagocytosis response is its self-regulation thrugh the products of macrophage breakdown (PMB). In a series of experiments with intraperitoneal and intratracheal injections of syngenetic PMB into rats and mice, it was shown that these products stimulate respiration and migration of phagocytic cells, their dose-dependent attraction to the site of PMB formation with the predominant NL contribution, increasing with the increase of amount of PMB, the AM and NL precursor cells recruitment from reserve pools, and the replenishment of these reserves in the process of hemopoiesis. At least some of the above effects are connected with the action of the lipid components of PMB. The action of specialized regulative systems of the organism can modify the response to PMB, judging by the results obtained by hydrocortisone injection. Autocontrol of alveolar phagocytosis requires great care in attempts at artificial stimulation of this process, as an excessive cell recruitment may promote the retention of particles in lungs.

Relation of pediatric blood lead levels to lead in gasoline.

Abstract: Analysis of a large data set of pediatric blood lead levels collected in New York City (1970-1976) shows a highly significant association between geometric mean blood lead levels and the amount of lead present in gasoline sold during the same period. This association was observed for all age and ethnic groups studied, and it suggests that possible exposure pathways other than ambient air should be considered. Even without detailed knowledge of the exact exposure pathways, sufficient information now exists for policy analysis and decisions relevant to controls and standards related to lead in gasoline and its effect on subsets of the population.

Concentration and size of asbestos in water supplies.

Abstract: A review of the results of over 1500 asbestos analyses from U.S. water supplies suggests that the majority of water consumers are not exposed to asbestos concentrations in their drinking water over...

Carcinogenicity and toxicity of methoxychlor.

Abstract: Methoxychlor is carcinogenic for the liver of C3H and BALB/c mice and Osborne-Mendel rats, and possibly for the liver of dogs. Methoxychlor is also carcinogenic for the testis of BALB/c male mice, bone of B6C3F1 female mice, and the ovary of Osborne-Mendel female rats. The incidences of carcinomas of the liver were increased in C3H male mice and BALB/c male and female mice fed methoxychlor. There also was an increase in malignant neoplasms at all sites in BALB/c male and female mice. C3H and BALB/c male mice were more susceptible to the carcinogenic effects of methoxychlor than were female mice. BALB/c mice were more susceptible than C3H mice. Osborne-Mendel male and female rats developed significant incidences of carcinomas of the liver. The incidence of sarcomas of the spleen and abdomen, mostly hemangiosarcomas, was increased in male rats. Neoplasms of the pituitary, adrenals, and mammary gland were also increased in methoxychlor-treated female rats. Miniature swine given methoxychlor developed chronic renal disease in relatively short periods of time. There also was hyperplasia of the mammary gland and uterus, suggesting an estrogen-like effect on those organs. Methoxychlor applied to the skin of rabbits caused a dose-related atrophy of the testes, as well as chronic renal disease. Atrophy of the testes and chronic renal disease could not be evaluated in mice and rats because of insufficient data.

Air pollution and human health: a review and reanalysis.

Abstract: Since 1970, Lave and Seskin have published a series of articles dealing with the question, "Does air pollution shorten lives?" Their recent book reports revised and extended analyses of their previ...

Experimental approaches for exposure to sized glass fibers.

Abstract: A number of studies have shown that glass fibers induce both malignant mesothelioma and fibrosis in rats and that these reactions may be primarily a function of the physical properties of the fiber...

The lung mast cell: its physiology and potential relevance to defense of the lung.

Abstract: The mast cell, located at mucosal surfaces and surrounding venules, is uniquely positioned to respond rapidly to insults to the host by mediating the development of a wide-ranging inflammatory response. Activaton of the mast cell releases preformed granule-associated chemical mediators and generates de novo biologically active materials. The properties of the mast cell mediators permit development of both acute and prolonged inflammatory responses. the immediate response is characterized by edema and the delayed response by leukocyte infiltration and vascular damage. the mast cell mediators responsible for these inflammatory events are characterized functionally. The vasoactive/smooth muscle reactive mediators include preformed histamine and serotonin and newly-generated platelet activating factor, slow reacting substance of anaphylaxis and prostaglandins. Chemotactic mediators include eosinophil-selective ECF-A and ECF-oligopeptides, neutrophil-selective NCF, and lipid chemotactic mediators with broad specificity. These factors induce directed migration and localization of leukocytes. The mast cell releases the structural proteoglycan, heparin, which is anticoagulant and inhibits complement. Released mast cell enzymes include chymotryptic and tryptic proteases, arylsulfatase, beta-glucuronidase, and hexosaminidase. The proteolytic enzymes may activate inflammatory pathways while the others degrade ground substance. The capacity of the mast cell to enhance vascular permeability, to cause the influx of regulatory or inflammatory leukocytes, and to provide a variety of active enzymes permits regulation of inflammatory events at the site of tissue injury.

Structural basis of ciliary movement.

Abstract: All motile somatic cilia, including those of the human respiratory tract, are similar in ultrastructure in that they consist of an axenome of 9 + 2 microtubules surrounded by a specialized extension of the cell membrane. The axonemal elements provide the ciliary motor, which is powered by ATP hydrolysis. In respiratory cilia, mutants occur where axonemal assembly is aberrant such that the doublet attachments known as arms (Afzelius and co-workers) or spokes (Sturgess) have been shown to be missing. These mutant cilia are apparently nonmotile. In model cilia, the arms are composed of dynein, a class of ATPase isoenzymes and associated polypeptides characterized byGibbons and colleagues. In negative stain preparations of arms, three subunits can be seen. In the presence of ATP, dynein functions with a set polarity to form transient cross-bridges that cause the microtubule doublets of the axoneme to slide relative to one another. After brief trypsin treatment, the axonemal microtubules slide almost completely apart with the arms of doublet n pushing doublet n + 1 in a tipward direction. To produce ciliary beating in vivo, sliding is carefully controlled and coordinated, in part probably by the spoke system. The ciliary membrane is responsible for maintaining the appropriate levels of ATP, Mg2+, and Ca2+, and Ca2+ (ca. 10(-7) M) around the axoneme. The beat of certain cilia--e.g., L cilia of mussel gills--can be arrested by increasing axonemal Ca2+ concentration, for example, in the presence of the ionophore A23187 and high external Ca2+. Although the net results of changes in axonemal Ca2+ concentration are not always complete stoppage of beat or of sliding, this ion is also part of the general behavioral control of ciliary motility.

Clinical tests in aquatic toxicology: state of the art.

Abstract: The state of the art of physiological, biochemical, and histological tests in aquatic toxicology is summarized. Currently utilized clinical tests are shown to have a low relative utility in determining aquatic toxicities. The problems associated with the development of diagnostic tests in aquatic toxicology are discussed. Considerations for improving the state of the art of diagnostic tests in aquatic toxicology are outlined. (20 references)

Instrumental aspects of positive and negative ion chemical ionization mass spectrometry.

Abstract: Differences in recording positive and negative ion chemical ionization mass spectra on a quadrupole mass spectrometer are discussed. An analog positive and negative ion electron multiplier detector...

Negative chemical ionization studied of human and food chain contamination with xenobiotic chemicals

Abstract: Negative chemical ionization mass spectrometry with a mixture of isobutane, methylene chloride, and oxygen as the reagent gas has been used to explore contamination of environmental substrates with xenobiotic chemicals The substrates in question, fish tissue, human seminal plasma, and human adipose tissue, were cleaned up by one of the following three cleanup procedures: (1) continuous liquid-liquid extraction steam distillation; (2) gel-permeation chromatography; and (3) adsorption on activated carbon followed by elution with toluene The third procedure was used only for the examination of planar polychlorinated aromatic hydrocarbons in environmental samples Using these techniques, we have found evidence for contamination of fish samples with polychloronaphthalenes, polychlorostyrenes, polychlorobiphenyls, polychlorodibenzofurans, and polychlorodibenzodioxins among other chemicals The polychlorodibenzodioxins appeared only in the spectra of extracts of fish obtained from the Tittabawassee River at Midland Michigan The polychlorodibenzofuran ions appeared in NCI mass spectra of fish that were significantly contaminated (above 2 ppm) with polychlorobiphenyls Toxic substances occurring in human seminal plasma included pentachlorophenol, hexachlorobenzene, DDT metabolites, and polychlorobiphenyls We have investigated toxic substances in human seminal plasma because of the apparent decrease in sperm density in US males over the last 30 years Results of screening human adipose tissue for contamination with xenobiotic chemicals have been largely coincident with result of the EPA human monitoring program Polychlorobiphenyls, DDT metabolites, nonachlor, and chlordane have appeared in most samples examined Detection limits for all of these chemicals were of the order of 1 ppb

Comparative studies on the cytotoxicity of amphibole and serpentine asbestos.

Abstract: The chemical and physical properties of serpentine and amphibole asbestos are considered in the context of their interaction with tissue of the tracheobronchial tree and lungs. In vitro studies in ...

Mesothelioma in man and experimental animals.

Abstract: Asbestos has been established as the cause of most cases of diffuse malignant mesothelioma occurring in the industrialized world. The morphology of mesothelioma may be complex, and the employment of chemical, histochemical and ultrastructural studies are often helpful in identification. Diagnostic difficulties may to some degree blur the extent of its prevalence and reliance on exposure history may not reveal its association with asbestos. Reference panels can be useful in assessing the former and analysis of lung tissue asbestos content may help to clarify the latter, especially in the low dose range. Electron microscopy may prove to be of assistance in this respect, possibly with particular attention to the peripheral areas of the lung. Animal experimentation has supported epidemiologic conclusions and revealed the phenomenon of fiber carcinogenesis. The morphology of mesothelioma in experimental animals is very similar to that in humans, including ultrastructural and biochemical features.

Experimental models for study of common respiratory viruses.

Abstract: Numerous epidemiological studies have shown that there is excess respiratory disease morbidity in areas of high atmospheric pollution, implying an interactive effect on the clinical illness associa...

Applications of a versatile technique for trace analysis: atmospheric pressure negative chemical ionization.

Abstract: The ability to use ambient air as a carrier and reagent gas in an atmospheric pressure chemical ionization source allows instantaneous air analysis to be combined with hypersensitivity toward a wid...

Human health hazards associated with chemical contamination of aquatic environment.

Abstract: Given the finite supply of water available for human use, continued chemical contamination of the aquatic environment may pose a significant human health hazard. Consequently, an effort must be mad...

Chemical modulation of airway epithelial permeability.

Abstract: The mucosal surface of the conducting airways has specialized structures for respiratory defense. Glands secret mucus that may act as a barrier to particle penetration and participate in particle clearance. Intraepithelial irritant receptors aid in particle clearance through airway constriction and cough. The epithelium acts as a barrier to the penetration of inhaled material into the airway wall. Morphologic studies have identified the tight junctions adjoining respiratory epithelial cells as the principal barrier to passive solute translocation across the airway. New approaches have been used to study airway epithelial function. Use of excised canine trachea mounted in Ussing chambers has permitted quantitative estimates of probe molecule permeation, the correlation of permeability with bioelectric properties, and estimation of equivalent pore radii. Probe molecule diffusion across canine trachea [mean transmucosal electric potential difference (PD) = 33 mV, lumen negative] is directly related to conductance (2.9 mS/cm2) and is compatible with an equivalent pore radius of 7.5 nm. Direct measurement of tracheal PD in vivo (-29 mV) facilitates study of the genesis of the biopotential in intact animals. Measurement of the movement of HRP by radioimmunoassay has allowed correlation of the rate of probe flow across airway walls in vivo with ultrastructure. These approaches lend themselves to the study of pharmacologic and toxicologic effects on epithelial function. Antigen challenge, diethyl ether, and unfractionated cigarette smoke have been shown to increase epithelial permeability to HRP accompanied by ultrastructural evidence of tight junctional damage. Application of pharmacologic agents, e.g. amphotericin, ouabain, onto the respiratory epithelium induces similar changes in in vitro and in vivo PD. We conclude that techniques that have been used to measure permeability and transport in other epithelia may help elucidate modes of action of environmental agents on airways.

Macrophage stimulation and the inflammatory response to asbestos.

Abstract: Chrysotile fibers injected into the peritoneal cavity of mice elicit a cellular exudate. Macrophages appearing in this exudate produce high levels of the neutral protease, plasminogen activator, wh...

Angiotensin-converting enzyme: I. New strategies for assay.

Abstract: The disposition of converting enzyme (kininase II) on the luminal surface of pulmonary endothelial cells is well established. Further, it is known that there is a net conversion of angiotensin I in...

Negative chemical ionization of alcohols.

Abstract: Reactions of the oxygen radical anion at low pressure (ICR conditions) with aliphatic alcohols are seen to give a limited number of product anions which allows for unambiguous determination of the structure of the neutral. The reactions of OH- are also investigated and mechanisms of reactions are discussed. Analytical application of NCI is also considered. OH- negative chemical ionization mass spectra, negative metastable ion spectra, and negative collisional activation spectra (negative product from negative precursor ions) have been applied to stereochemical problems of cyclic diols. The spectra of the cis and trans isomers of 1,3- and 1,4-cyclohexanediols and 1,2- cyclopentanediols show substantial and characteristic differences. The (M-H)- alkoxide anions produced by OH- reagent ions are stabilized for the cis isomers by formation of an intramolecular hydrogen bridge involving both oxygen functions. However, trans geometry of the (M-H)- ions is indicated by abundant (M-H3)- and/or (M-H-H2O) fragment ions. The stereospecificity increases with ion internal energy (high temperature, collisional activation) or especially with ion life times (metastable ions). It is shown that in F- negative chemical ionization the relative intensities of the fluoride attachment ions MF- and of the proton abstraction ions (M-H)- reflect the stereochemistry of the cyclic diols. The results demonstrate the potential of negative ion mass spectrometry for stereochemical investigations.

Studies of negative ions by collision-induced decomposition and hydrogen-deuterium exchange techniques.

Abstract: Development of two new techniques for studying the gas phase chemistry of negative ions is reported. Collision induced dissociation (CID) of (M-1)- ions has been accomplished in a newly constructed...