Diminution in kerosene-mediated induction of drug metabolizing enzymes by asbestos in rat lungs

In order to determine the pulmonary toxicity of kerosene and its ignition product (soot) in asbestos exposed subjects, the activities of phase I and phase II drug metabolizing enzymes in rat lungs after single intratracheal co-exposure to Indian chrysotile asbestos and kerosene or its soot and Indian chrysotile were assayed. Exposure to kerosene or its soot resulted in a significant increase in the level of microsomal cytochrome P-450 and the activity of P-450 dependent monooxygenase, benzo(a)pyrene hydroxylase, as well as in the activities of microsomal epoxide hydrase and cytosolic glutathione-S-transferase (GST). However, in chrysotile exposed animals a reverse pattern in these parameters was recorded. The co-exposure to chrysotile and kerosene or chrysotile and soot led to a significant depletion in cytochrome P-450 level and a decrease in the activities of benzo(a)pyrene hydroxylase, epoxide hydrase and GST when compared to kerosene and soot controls, respectively. These results suggest that asbestos by altering the pulmonary drug metabolizing enzyme system may increase the toxic potential of kerosene and its ignition product in the respiratory system.

In vitro activity of silicon carbide whiskers in comparison to other industrial fibers using four cell culture systems

Silicon carbide whiskers (SiCW) and continuous glass filaments are important components of composite materials having potentially widespread use in the automotive, aerospace, and power generation industries. We determined the in vitro activity of three well-characterized samples of silicon carbide whiskers and a continuous glass filament sample in four different cellular assays and compared this to the activities of UICC crocidolite, JM Code 100 glass microfiber, and erionite in the same assay systems. The SiCW had a diameter range of 0.32-0.75 microns and a length range of 4.5-20.1 microns. The SiCW was significantly toxic; on a mass basis, one SiCW sample was more toxic than crocidolite; however, JM Code 100 glass microfiber, which is not toxic in vivo (i.e., it does not cause fibrogenesis or carcinogenesis when inhaled), was also more toxic than crocidolite. The glass filament sample was the least cytotoxic of all the samples tested. On a fiber number basis, all three SiCW samples were more toxic than crocidolite. The results of our study showed that SiCW exhibits significant in vitro biological reactivity. Thus, despite the caution that must be exercised in extrpolating the results of in vitro studies to conclusions about in vivo health effects, SiCW should be considered toxic until further toxicological data are available.

Mutagenicity spectra in bacterial strains of airborne and engine exhaust particulate extracts

The mutagenicity spectra of the organic extracts of both airborne particulate matter and diesel and gasoline soot particles were determined using a battery of 9 bacterial strains of different genetic specificity. The assays with crude extracts and with fractionated acidic, neutral and basic components revealed striking differences in the patterns of mutagenic responses produced by each of the complex mixtures investigated. The mutagenicity of air particulate matter was shown to depend mainly on direct-acting acidic and neutral compounds, with a lesser contribution of basic promutagens which required exogenous metabolic activation by liver S9. The assays with a diesel soot extract indicated the prevailing contribution of direct-acting acidic and neutral compounds, and suggested an important role also for nitro derivatives other than nitropyrenes. The gasoline exhaust was characterized by powerful promutagenic compounds, belonging to either the acidic, neutral or basic fractions. The implications of these results are discussed with respect to the contribution of engine exhausts to air pollution, and the possible use of mutagenicity spectra in the analysis of environmental complex mixtures.

Toxicology and occupational hazards of new materials and processes in metal surface treatment, powder metallurgy, technical ceramics, and fiber-reinforced plastics

Many new materials and processes are about to find their way from the research laboratory into industry. The present paper describes some of these processes and provides an overview of possible occupational hazards and a list of chemicals used or produced in the processes. The technological areas that are considered are metal surface treatment (ion implantation, physical and chemical vapor deposition, plasma spraying), powder metallurgy, advanced technical ceramics, and fiber-reinforced plastics.

The generation and characterization of silicon carbide whiskers (fibers) for inhalation toxicology studies

Atmospheres of silicon carbide whiskers (wh) were required for a repeated dose lung deposition study and a subchronic inhalation toxicity study, each involving exposure to three concentrations of whiskers for 6 hr/day, 5 days/week for 1 or 13 weeks. Target concentrations were 0, 500, 1500, and 7500 wh/cc. By using the mean fiber length (10 microns), diameter (0.555 micron), and density (3.2 g/cc) of the bulk material, target mass concentrations were approximately 0, 4, 12, and 60 mg/m3. The Pitt III generator, developed for cotton fiber dispersion at the University of Pittsburgh, was selected. This instrument consists of a vertical 18-in. long cylinder, which is closed at each end with rubber dams and coupled at the base to a loudspeaker. The sonic energy from the loudspeaker fluidizes the test material and the whiskers in the air column are carried out with the exhaust air. The output of the Pitt III generator was altered by changing the sound energy input, the rate of introduction of the test material into the fluidizing cylinder, or the airflow through the cylinder. Separate generation systems were used for each inhalation chamber. Chamber atmospheres were characterized gravimetrically and samples were analyzed by scanning electron microscopy. Mean mass and number concentrations for the subchronic study were 0.09, 3.93, 10.7, and 60.5 mg/m3 and 0, 630, 1746, and 7276 wh/cc, respectively. Weighted mean values for whisker diameters, lengths, and aspect ratios were 0.560 micron, 4.53 microns, and 8.62, respectively. Although whisker lengths were less than half those of the bulk material, nearly 30% of the whiskers were greater than 5 microns long.

[Toxicological study of materials for artificial heart valves]

The toxicological study was performed in order to establish the optimum carbon thromboresistant coat of titanium in creating new constructions of the artificial heart valves under conditions of chronic experiments in albino rats. Fine samples of carbon coats made by different techniques were studied. The biological activity of only one coat made by the method of ionoplasmic spraying with using chemically pure carbon target was established.

A subchronic inhalation toxicity study in rats exposed to silicon carbide whiskers

To determine whether inhaled silicon carbide whiskers (SiC) cause lung damage in rats, four groups (50 males/50 females each) of rats were exposed to air only or to one of three concentrations of SiC 6 hr/day, 5 days/week for 13 weeks. Half (25 males/25 females/group) were euthanized at the end of exposure, the remainder 26 weeks later. Mean concentrations were 0, 630, 1746, and 7276 SiC whiskers/ml (0.09, 3.93, 10.7, and 60.5 mg/m3). Although there were no concentration-related changes in body weight, clinical chemistry, or hematological data attributable to SiC, lung weights were increased in the high concentration exposure group at both euthanization times. In all whisker-exposed groups, after 13 weeks of exposure, the incidence of the following lung and lymph node lesions was higher than in controls: inflammatory lesions; bronchiolar, alveolar, and pleural wall thickening; focal pleural fibrosis in lung; and reactive lymphoid hyperplasia in bronchial and mediastinal lymph nodes. After 26 weeks of recovery, lung inflammatory lesions had decreased and fewer rats had enlarged lymph nodes, but the incidence of alveolar wall thickening, focal pleural wall thickening, and adenomatous hyperplasia of lung had increased further. Incidence and severity appeared to be dose-related. Therefore, until longer term studies are undertaken and it is established whether the above observed lesions will progress to more severe pathological entities, it is prudent to adopt stringent handling procedures for silicon carbide whiskers.

Alterations in in vitro functional activities of alveolar macrophages exposed in vivo to mineral dusts

To determine whether macrophages exposed to mineral dusts are altered, rats were exposed intratracheally to one of several mineral dusts, held 8 days, their lungs washed and the cellular composition of the fluid characterized morphologically and functionally. The number of cells recovered from lung washings of exposed rats increased 2 to 5 times relative to control rats; however, the percentage of such cells that were macrophages, or were capable of phagocytosis, adherence to glass or metabolism of carbohydrates via the hexose monophosphate shunt as indicated by reduction of nitroblue tetrazolium, were reduced. Silica dust produced the greatest effect, corresponding qualitatively to earlier in vivo studies.

Suppression of alveolar macrophage membrane receptor-mediated phagocytosis by model and actual particle-adsorbate complexes. Initial contact with the alveolar macrophage membrane

Alveolar macrophages were treated with carbon blacks and adsorbates in order to evaluate the biologic effect of adsorbate, adsorbent and adsorbate-adsorbent complexes. Their capacity to phagocytize a subsequent challenge via the Fc-membrane receptor was quantified. Phagocytosis was suppressed in a dose-related manner with increasing concentrations of both carbon blacks and adsorbates. Carbon black N339 covered with 0.5 monolayers of the adsorbates suppressed phagocytosis more than N339 without the adsorbates. Increasing the adsorbate acrolein coverage from 0.5 to greater than 2.0 monolayers suppressed phagocytosis in a dose-related manner. Finally, samples of diesel particulate matter collected from an engine operated on a pure hydrocarbon fuel with various oxidizers, air (PSU #1) and an oxidizer free of nitrogen (N-free) were tested. Treatment of the macrophages with PSU #1 had a negligible effect on phagocytosis whereas the N-free sample suppressed phagocytosis in a dose-related manner. The data show that alveolar macrophage Fc-receptor-mediated phagocytosis is affected by: carbon black and adsorbate identity and concentration, coverage of the carbon black with adsorbates, and the oxidizer used in the generation of particles emitted by a diesel engine.

[Element composition of aerosol exhaust from thermal stations using coal]

Out of the whole number of impurities (more than 30) detected in aerosol discharge of TES using Cheliabinsk mine coal only for 16 of them MACs for the air of residentials areas or tentative safe exposure levels were established. The most important from the hygienic point of view are dust, aluminum, iron, manganese, barium, vanadium and lead.

An evaluation of the "in vivo" and "in vitro" biological reaction and mechanical features of carbon fibre composites

Tissue reaction to an epoxy resin-carbon fibre composite was tested "in vivo" and "in vitro" in order to evaluate this material as an alternative to metal alloys for clinical use in orthopaedic surgery. While the "in vitro" tests suggest a mild toxic effect of the composite on cells, good biocompatibility "in vivo" was observed when debris are not generated. The mechanical tests compared the composite and stainless steel plates, confirming the expected values for static strength and elastic modulus, revealing, however, the formation of long needles of carbon fibre following breakage of the plate.

Reduction in pulmonary and hepatic respiratory cytochrome contents by fly ash inhalation in rats

Exposure of rats to fly ash for 15 days, 6 hours daily, inhibited pulmonary and hepatic NADH-oxidase activity. The content of cytochrome b and cytochromes a + a3 was significantly lower in the lungs of the fly-ash-exposed group. However, in liver, fly ash exposure reduced the cytochrome a + a3 level without affecting the cytochrome b content, indicating a tissue-specific effect. Mitochondrial protein content in both organs was the same in both groups.

Effects of inhaled municipal refuse incinerator fly ash in the guinea pig

Fly ash was collected from two municipal refuse incinerators. It was analyzed for heavy metals, elements, and a wide range of toxic organics. It was resuspended in air for inhalation exposure of guinea pigs. These animals were exposed at high concentrations of each ash 6 h/d for 5 d, and tissues were taken 45 d after the exposure. Following the first exposure and after each daily exposure the ventilatory response of these animals upon challenge with CO2 was found to be depressed. Recovery occurred following exposure. Heavy metals, cadmium, lead, zinc, and mercury were elevated in the lungs of these animals. Histologic evaluation of pulmonary tissue revealed multifocal pneumoconiosis. Interstitial infiltration by macrophages and smooth muscle hypertrophy of blood vessels and bronchioles were also observed. There was no evidence of a dioxinlike toxic effect following inhalation of these ashes.

Genotoxic effects of fly ash in bacteria, mammalian cells and animals

The increasing use of fossil fuels has raised concerns about possible deleterious health effects of the final combustion product, fly ash. Seven ash samples from coal sources obtained from Battelle Columbus Laboratories were evaluated in the Salmonella/mammalian microsome mutagenicity assay to determine their mutagenic potential. While dimethyl sulfoxide extracts of five samples showed no mutagenicity, sample 102 caused an increase in the number of revertants per plate over controls in TA100 and TA98 with activation by liver homogenate (2-fold and 2.4-fold, respectively), and without (2-fold and 6-fold). This ash was thus evaluated in whole animal studies. Animals treated by inhalation or oral gavage were assayed for the presence of mutagens in the urine, micronuclei in polychromatic erythrocytes, and chromosomal aberrations in metaphase bone marrow cells. Those animals treated by inhalation were also examined for local damage in the lung. The assay for mutagens in the urine was negative as shown by the Ames assay with TA100 and TA98 and there was no increase in micronuclei or in metaphase aberrations. Histological sections from the animals treated by inhalation did not show the presence of particles, macrophage infiltrations and generalized lung damage. We tested the same fly ash with an in vitro cell transformation assay with the cell line Balb/c 3T3 subclone A31-1-13. Although there was not an increase in Type III foci, there was a dose-dependent increase of Type II foci in the treated cells over the controls. In one assay, there was approximately a 14-fold increase in Type II foci in the highest dose (2 mg/ml) compared to the solvent control. One other ash sample induced cell transformation without being markedly cytotoxic, while a third sample was highly toxic but did not induce transformation.

Long-term carcinogenicity study in Syrian golden hamster of particulate emissions from coal- and oil-fired power plants

Male Syrian golden hamsters were given 15 weekly intratracheal instillations with suspensions of coal fly ash or oil fly ash. Controls were instilled with saline containing gelatine (0.5 g/100 mL) or to check particle effects with suspensions of hematite (Fe2O3). The common weekly dose was 4.5 mg/hamster. In addition, one subgroup of hamsters was treated with oil fly ash at a weekly dose of 3.0 mg/hamster and another with coal fly ash at a weekly dose of 6.0 mg/hamster. Other groups of hamsters were treated with suspensions of benzo[a]pyrene (BaP) or with suspensions on coal fly ash, oil fly ash, or Fe2O3 coated with BaP. The mass median aerodynamic diameters of the coal and oil fly ashes were 4.4 microns and 28 microns, respectively. Hamsters treated with oil fly ash showed a higher frequency of bronchiolar-alveolar hyperplasia than hamsters in the other treatment groups. Squamous dysplasia and squamous metaplasia were most frequent in animals treated with suspensions of BaP or BaP-coated particles. The earliest appearance of a tumor, the highest incidence of tumors, and the highest incidence of malignant tumors were observed in hamsters treated with oil fly ash coated with BaP. Squamous cell carcinoma and adenosquamous carcinoma were the most frequent malignant tumors. No malignant tumors and only few benign tumors were observed in hamsters instilled with suspensions of fly ash not coated with BaP. The present study gives no indication that coal fly ash could create more serious health problems than oil fly ash.

Release of corrosion products by F-75 cobalt base alloy in the rat. III: Effects of a carbon surface coating

A pyrolytic carbon coating was applied to F-75 chromium-cobalt-molybdenum alloy in an effort to reduce the release of corrosion products in vivo. After intramuscular implantation in the rat, a complex pattern of serum and urine concentration elevations of chromium, cobalt, and nickel was seen. The carbon-coated implants released more chromium and cobalt than uncoated controls, as seen by significantly elevated metal concentrations in serum and urine. Animals receiving carbon-coated implants showed a high rate of recurrent implant site inflammation. Neoplastic infiltration of 24 animals with coated implants, but not in any of the 16 animals which received either uncoated F-75 microsphere or poly(ethylene) particulate implants.

[Compatibility of glass-carbon implants in the middle ear--animal experiment studies]

28 tympanoplastic procedures with destruction and reconstruction of the ossicular chain were performed in rabbits. Vitreous carbon implants were used as prosthetic material. The animals were followed up from 14 days to one year. In 23 cases extensive inflammation of the middle ear mucosa was observed macroscopically. The histological findings were formation of an increasing fibrous capsule with duration of time, permanent foreign body reaction at the surface of the implants and missing formation of new bone or contact with bone respectively. Thus vitreous carbon seems to be a less promising material in middle ear surgery.

Co-carcinogenic effect of carbon black ingestion with dietary fat on the development of colon tumors in rats

Previous studies in our laboratory on the co-carcinogenic effect of the ingestion of an industrial carbon black (CB) on chemically induced colon cancer in rats and mice demonstrated no differences in tumor incidences attributable to CB feeding. The present study examined the effect of CB ingestion within the context of a high fat diet, formulated to simulate the typical diet of western industrialized nations. Corn oil was added to ground commercial chow at 20% by weight and CB added at 2.05 g/kg diet and fed for 52 weeks to female Sprague-Dawley rats. Colon tumors were induced with 16 weekly injections of 1,2-dimethylhydrazine (DMH, 10 mg/kg body weight). Tumor incidences in DMH-treated rats ingesting CB were significantly (P less than 0.05) higher than in those with no CB added to the diet (76% vs. 60%). The survival of CB + DMH treated animals (64%) was also lower than that of animals treated with DMH and not ingesting CB (80%). These findings may implicate CB ingestion as a co-carcinogen for industrial workers when acting in synergism with high fat diets and other unknown colon carcinogens.

Evaluation of occupational exposure to mixed dusts and polycyclic aromatic hydrocarbons in silicon carbide plants

Workers in the silicon carbide industry have experienced occupational health diseases, particularly lung disorders such as silicosis. The silicon carbide production process mainly employs petroleum coke, sawdust, pure crystalline silica and graphite. Since crystalline silica is present in the occupational environment, the airborne dust content of various polymorphs of silica, especially quartz, cristobalite and tridymite, was determined by X-ray diffraction analysis. The analytical method was modified to eliminate graphite, since it overlaps with the main diffraction plane of quartz. Exploratory field surveys were conducted to identify the minerals present in that occupational environment and to evaluate the validity of the analytical method. The surveys provided information on the mineralogical nature of the dust, its respirable content and the concentration of silica polymorphs. Polycyclic aromatic hydrocarbons also were measured, and the effect of their adsorption on graphite was evaluated.

Correlation of nitroaromatic compounds with the mutagenic activity of coal fly ash

Stack-collected fly-ash particles from a commercial pulverized-coal power plant were extracted with 60/40 w/w benzene-methanol to remove as much of the organic fraction as possible. The extract was sequentially fractionated on a series of high-performance liquid chromatography columns, and the Salmonella bacterial mutagenicity assay using both normal and nitroreductase-deficient strains was used to localize the most mutagenic fractions. Selected fractions were analyzed by a variety of techniques, including gas chromatography with dual-flame ionization and thermionic nitrogen-phosphorus detectors, gas chromatography-mass spectrometry, direct-probe low-resolution or low-voltage mass spectrometry, and high-resolution mass spectrometry. Mutagenicity data indicated that nitroorganic compounds were the primary mutagens in all samples submitted for chemical analysis. A series of homologous alkylated nitrophenanthrenes appear to be important mutagens in one major fraction, while alkylated nitrofluorenones appear to be the dominant mutagens in a second major fraction. No nitro compounds were identified in a third major fraction. In addition to the nitro compounds, substantial amounts of fluorenones were also found, although these are not believed to contribute to the direct-acting mutagenic activity of the samples.

Mutagenic activity of carbon black dyes used in the leather industry

Seven carbon black pastes used as commercial leather dyes were tested for their mutagenicity in the Salmonella/microsome test (TA98 and TA100 strains). All the samples assayed either directly or after extraction with a 30-min sonication in benzene were devoid of mutagenicity both in the presence and absence of a metabolic activation preparation. After a 48-h extraction with boiling toluene in a Soxhlet apparatus, four samples were mutagenic in TA98 strain in the presence of S9 mix. The activity ranged from 1.3 to 9.6 induced revertants/mg equivalent of extract. A weak direct mutagenic activity in strain TA98 was shown by one extract. Polycyclic aromatic hydrocarbons (PAH) were determined in the toluene extracts by high resolution gas chromatography/mass spectrometry. The presence of PAH could explain the mutagenicity of only one sample (8.79 micrograms of total PAH/100 mg equivalents of extract), while low or undetectable levels of PAH were found in the other mutagenic extracts. The mutagenic activity was evident only after a vigorous extraction process, thus a low bioavailability of the mutagens present in these compounds is suggested.

Subchronic inhalation toxicology of carbon fibers

Male Sprague Dawley rats were exposed to carbon fibers 7 microns in diameter and 20 to 60 microns in length, for six hours a day and five days a week for up to 16 weeks at an average chamber concentration of 20 mg/m3. Rats were killed at 4, 8, 12, and 16 weeks of exposure and after a 32-week postexposure recovery period. A similar number of control rats exposed only to air were killed at the same times. Pulmonary function tests, conducted just prior to the animals' death, did not demonstrate any significant or consistent changes. The only pulmonary finding that could be causally related to the subchronic inhalation of carbon fibers was phagocytosis of the inhaled particles by alveolar macrophages. This physiologic response was not accompanied by any local reactive pulmonary inflammation or fibrosis.

Subchronic oral toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin in the guinea pig: comparisons with a PCB-containing transformer fluid pyrolysate

In contrast to the well-characterized acute toxicity of the environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) in the guinea pig, the effects of prolonged po exposure in this species are unknown. The present report describes the results of administration to guinea pigs of 2,3,7,8-TCDD in the feed at levels of 0, 2, 10, 76, or 430 ppt for up to 90 days. Additional aims were to examine recovery following prolonged 2,3,7,8-TCDD exposure in the guinea pig and to generate data to facilitate comparison of the previously reported toxicity of a transformer fluid pyrolysate with that of pure 2,3,7,8-TCDD. Animals receiving 430 ppt 2,3,7,8-TCDD exhibited body weight loss, thymic atrophy, liver enlargement, and 60% mortality by Day 46 (males) and by Day 60 (females), when surviving animals in this group were sacrificed. Total 2,3,7,8-TCDD consumption was approximately 1.3 and 1.9 micrograms/kg, respectively. Animals receiving 76 ppt 2,3,7,8-TCDD for 90 days (total 0.44 microgram/kg) exhibited a decreased rate of body weight gain and increased relative (to body) liver weights. Male animals also displayed a reduction in relative thymus weights and elevated serum triglycerides, while females exhibited hepatocellular cytoplasmic inclusion bodies and lowered serum alanine aminotransferase activities. Toxic effects were generally similar to those observed after acute 2,3,7,8-TCDD administration. No dose-related alterations were seen in animals receiving either 10 ppt (total 0.06 micrograms/kg) or 2 ppt (total 0.01 micrograms/kg) for 90 days, establishing a no-observed-effect level of approximately 0.65 ng 2,3,7,8-TCDD/kg/day. In the recovery study, groups of guinea pigs were administered 430 ppt 2,3,7,8-TCDD for 11, 21, or 35 days and then allowed to recover for an additional 79, 69, or 55 days, respectively. Treatment-related mortality in each group was 0, 10, and 70%, respectively, by Day 90. An effective LD50 of 0.8 microgram 2,3,7,8-TCDD/kg for prolonged exposure was calculated on the basis of these results, a value lower than those previously reported from this laboratory for acute exposure. The results also suggested a possible lowering of the body weight "set point" following 2,3,7,8-TCDD exposure. Comparison of the present findings with those previously reported for a transformer fluid pyrolysate containing a mixture of polychlorinated aromatic species indicated both a greater variety of toxic effects and flatter dose-response relationships for the pyrolysate in the guinea pig.

Hepatic microsomal phospholipids in rats exposed intratracheally to coal fly ash

The effects of intratracheal administration of fly ash (50 mg/kg body weight, daily for 7 days) on hepatic microsomal phospholipid metabolism has been studied in rats using various phospholipid precursors, viz NaH2(32)PO4, (methyl-14C)-choline, and (methyl-14C)-methionine. Fly ash administration significantly increased microsomal phosphatidylcholine (PC), and lysophosphatidylcholine (LPC). The incorporation of NaH2(32)PO4 into total liver phospholipids, PC and Phosphatidyl ethanolamine (PE) was significantly increased in fly ash-treated rats as compared to the control. Fly ash administration also increased the incorporation of (methyl-14C)-choline into microsomal PC. Incorporation of (methyl-14C)-methionine into microsomal PC was not affected. Fly ash administration decreased the per cent distribution of arachidonic acid in PC and PE and increased that of oleic acid in PC and of linoleic acid in PE.

Inhibition of coal fly ash polycyclic aromatic hydrocarbons and metals induced mixed-function oxidase activity in rat lung and liver by vitamin A and citrate

Administration of benzene-soluble fraction (FAE) and benzene-insoluble fraction (FAR) of fly ash for 3 consecutive days to rats significantly raised cytochrome P-450 levels, aryl hydrocarbon hydroxylase (AHH) activity, and glutathione S-transferase activity in liver. This treatment also significantly increased pulmonary AHH and glutathione S-transferase activity. Intratracheal administration of FAR (5 mg/100 g body weight) alone for 6 consecutive days also significantly increased hepatic cytochrome P-450 levels and the activity of glutathione S-transferase. Intragastric administration of retinyl palmitate (5000 IU/100 g body weight), along with intratracheal FAE and FAR administration, significantly reduced P-450 levels, activity of glutathione S-transferase in liver, and activity of AHH and glutathione S-transferase in lung of rats. Intraperitoneal administration of citrate (40 mg/100 g body weight) along with FAR significantly reduced FAR-induced increase in hepatic cytochrome P-450 levels and glutathione S-transferase activity. The activity of AHH was not affected by these treatments.

Prolonged cataleptogenic effects of potentized homoeopathic drugs

The four homoeopathic drugs, Gelsemium, Cannabis Indica, Graphites and Agaricus Muscarius, administered orally in 30th and 200th potencies on white rats, enhanced restraint-induced catalepsy in a similar manner to the two standard drugs pilocarpine and haloperidol (IP injection at 5 mg/kg). All the drugs tested differed from each other in the duration of cataleptogenic effect, which was more prolonged with Cannabis, Graphites and Agaricus than with Gelsemium and the two non-homoeopathic drugs used. The 200th potency of any homoeopathic drug tested acted longer than its 30th potency.

Development of alterations in hamster distal lung following exposure to fly ash from fluidized bed coal combustion: a morphometric study

Fly ash (30 mg) from an experimental fluidized bed coal combustor (FBC) was intratracheally instilled once into male Syrian golden hamsters. At 1, 3, 6, 9, or 30 days postadministration, lungs were fixed by intratracheal perfusion and tissues were processed for light and electron microscopic evaluation. Standard point count morphometry, used to analyze distal lung structures, revealed: an increase in volume density (Vv) of noncellular interstitial space at Day 1 which remained elevated at Day 3 but returned to control values subsequently; increased Vv for polymorphonuclear leukocytes (PMNs) and alveolar macrophages in alveolar air space at Day 6; increased Vv of cellular interstitium at Day 9; and increased Vv of noncellular interstitium at Day 30 following exposure. These observations are consistent with the hypothesis that the primary response of the distal lung to particle exposure is recruitment of PMNs and macrophages. When activated, these cells may release substances affecting the cellular and noncellular composition of the interstitial space, leading eventually to increased connective tissue in the interstitium.

Effects of short-term exposure to diesel exhaust on lung cell proliferation and phospholipid metabolism

The effect of exposure to diesel exhaust (DE) on DNA synthesis in lung tissue and type II cells was investigated. Parallel experiments with carbon black (CB) and NO2 were designed to mimic exposure to individual components of DE. Continuous exposure to 6 mg/m3 DE particulate or 7 ppm NO2 elicited significant increases in DNA synthesis and type II cell labeling index. The maximal response occurred after 2 days of exposure, and all measures returned to control levels after one week. Exposure to 6 mg/m3 CB did not cause similar changes, suggesting that the initial wave of cell proliferation elicited by DE exposure may be related to the presence of NO2 in the exhaust. In investigations of the effect of DE exposure on lung lipid metabolism, the incorporation in vivo of 14C-palmitic acid into lung tissue phosphatidylcholine increased three-fold after the first exposure day, when tissue palmitic acid content was significantly decreased and lavaged phospholipid (PL) increased. In vitro measures of PL biosynthesis showed no changes. These results suggest that exposure to a high concentration of DE results in immediate, transient changes in fatty acid and PL metabolism, but that these effects are not necessarily related to a stimulation of PL biosynthesis.

Induction of pulmonary drug metabolizing enzymes by coal fly ash in rats

The effect of intratracheal administration of fly ash, benzene extracted fly ash residue and benzene extract of fly ash has been studied on the activity of pulmonary mixed function oxidase. Fly ash, its benzene extract and benzene extracted residue significantly increased the levels of cytochrome P-450, cytochrome b5 and the activities of NADPH-cytochrome c reductase, NADH cytochrome b5 reductase, aminopyrine N-demethylase and glutathione S-transferase in a dose dependent manner. Phenobarbital or 3-methylcholanthrene treatment along with administration of fly ash, its benzene extracted residue and benzene extract of fly ash showed a synergistic effect on the activity of mixed function oxidase. The observed effects were due to chemical causes, i.e. organic and inorganic fractions of fly ash and not, due to its particulate nature. This was shown by the administration of glass beads which caused no alteration in the activity of pulmonary mixed function oxidase.

The effect of carbon black ingestion on 1,2-dimethylhydrazine-induced colon carcinogenesis in rats and mice

The possible co-carcinogenic effect of ingestion of industrial carbon black was examined in female Sprague-Dawley rats and female CF1 mice treated with 1,2-dimethylhydrazine (DMH) to induce adenocarcinomas of the colon. Carbon black was added to the diet at 2.05 g/kg feed and fed for 52 weeks. No differences (P greater than 0.05) in tumor incidences were seen in rats or mice. Simultaneous 2-year feeding experiments with carbon black alone showed no increase in the development of spontaneous tumors. These findings are consistent with the belief that carbon blacks are ineffective as carcinogens because of their adsorptive properties.

Inhalable particles and pulmonary host defense: in vivo and in vitro effects of ambient air and combustion particles

The ability of particulate air pollutants (and possible constituents) to alter pulmonary host defenses was examined using an in vitro alveolar macrophage cytotoxicity assay and an in vivo bacterial infectivity screening test which employed intratracheal injection of the particles. A wide range of response between particles was seen at the 1.0-mg/ml level in vitro and the 0.1-mg/mouse level in vivo. A sample of fluidized-bed coal fly ash, bentonite, asbestos, some ambient air particles, and heavy metal oxides greatly increased susceptibility to pulmonary bacterial infection. Most coal fly ash samples and some air particles caused moderate increases in infectivity, while diesel particulates, volcanic ash, and crystalline silica caused only small increases. Cytotoxic effects on macrophages in vitro were observed with most of the particles. The in vivo and in vitro assays produced a similar ranking of toxicity; however, not all particles that were highly cytotoxic were potent in increasing bacterial infectivity. Increased toxicity measurable by either assay often appeared to be associated with small size or with the presence of metal in the particles.

In vitro biological effects of volcanic ash from Mount Sakurajima

Mount Sakurajima in the south of the Kyushu Island of Japan erupts hundreds of times a year and continuously emits large amounts of ash. More than a million people live under this ash plume, and there is considerable concern about the possible effects of this on their health. We have studied the physicochemical characteristics and in vitro effects of airborne ash collected at 8 km from the crater. More than 30% of the ash was found to be SiO2 (w/w) with most of the particles within the respirable size range. The ash did not inhibit the colony formation of V79-4 cells and failed to activate complement or generate chemotactic factor activity in samples of fresh human serum. It was minimally active in causing the release of lysosomal enzymes from human neutrophile, and did not cause arachidonic acid release from macrophage-like cells. These results were in accord with our epidemiological study, in which very low prevalences of nonspecific respiratory disease were demonstrated even at the area with highest ash exposure.

Cytokinetic and morphological changes in the lungs and lung-associated lymph nodes of rats after inhalation of fly ash

Fischer-344 rats (male and female) were exposed to 36 mg/m3 of fluidized bed coal combustion fly ash or sham-exposed for 7 hr/day, 5 days/week for 4 weeks, and sacrificed after 2 or 4 weeks of exposure and at 2, 22, and 42 weeks after the end of exposure. Animals were injected with tritiated thymidine 2 hr before sacrifice and autoradiographs prepared from 1-micron sections of lung and lymph node tissue embedded in glycol methacrylate plastic. Differences in labeling indices of pulmonary epithelial cells, alveolar macrophages, airway epithelial cells, and cells of the lung-associated lymph nodes between the exposed and control animals were maximal after 2 and 4 weeks of exposure. Labeling indices for lung epithelial cells were about the same in control and exposed animals at 2, 22, and 42 weeks after the end of exposure. However, these values were elevated relative to earlier control levels. In contrast, morphological changes in the fly ash-exposed animals were most prominent after the end of the exposure. These changes included thickening of the alveolar walls, clusters of particle-filled macrophages in the alveolar region, and perivascular inflammation. Additionally, there were small granulomas in the alveolar region at 42 weeks after the end of exposure. Granulomas were also formed in the lung-associated lymph nodes and and bronchus-associated lymphoid tissue. We conclude that the inhalation of fly ash alone had little detrimental effect upon the rat lung. However, the increases in proliferation indicate the potential for fly ash combined with a carcinogen to enhance the carcinogen's effect.

Application of an in vitro keratinization assay to extracts of soot from a fire in a polychlorinated biphenyl-containing transformer

A fire in the State Office Building in Binghamton, New York, involving a polychlorinated biphenyl-containing electrical transformer, resulted in contamination of the structure with soot containing 2,3,7,8-tetrachlorodibenzo-p-dioxin and 2,3,7,8-tetrachlorodibenzofuran. Benzene extracts of soot collected from various areas of the building were tested for in vitro keratinization-inducing activity by the method of J. C. Knutson and A. Poland (Cell 22, 27-36, 1980). The results, in terms of relative keratinization-inducing activity, are compared to a high-resolution gas chromatographic/mass spectrometric analysis for total polychlorinated dibenzofurans in the same samples. This comparison showed a good correlation and suggests that the in vitro keratinization model has potential for use as a semiquantitative assay for dioxinlike activity.

The comparative toxicity of volcanic ash and quartz. Effects on cells derived from the human lung

To evaluate the effects of volcanic ash and free crystalline silica on cells derived from the air space of the human lung, we compared the effects of these minerals on human alveolar macrophages and A549 cells, which are derived from human type II pneumocytes. The quartz was markedly cytotoxic to alveolar macrophages and A549 cells and stimulated the release of neutrophil chemotactic activity from alveolar macrophages. By contrast, volcanic ash was much less toxic to human alveolar macrophages and A549 cells and did not stimulate the release of neutrophil chemotactic activity from alveolar macrophages. The results with A549 cells were similar to findings with isolated type II pneumocytes recovered from rat lungs. Secretory IgA, IgG, and albumin, which are normally present in the air spaces of the lung, reduced the cytotoxicity of quartz in a dose-dependent manner. These results suggest that in the human lung quartz, but not volcanic ash, may cause direct damage to cells in the alveolar spaces and lead to the recruitment of phagocytes from the bloodstream to the lung.

Effect of trace elements found in coal fly ash, on lymphocyte blastogenesis

To evaluate the potential health effects of coal fly ash, a byproduct of coal combustion for electrical energy production, on the immune system, we studied the effects of trace elements found in fly ash on lymphocyte blastogenesis. Of the sixteen trace elements studied, seven inhibited lectin-induced lymphocyte division, six showed no inhibition and three produced inconsistent effects. The ranking of the toxicity of the elements is Mn, V, As (III), Cu, Cd, Se, and Be. Our data indicate that whole blood lectin-induced lymphocyte blastogenesis is a sensitive and reproducible test for in vitro screening of trace elements affecting the immune system.