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Biomedical subjects

E J Fairchild

Publications and source records attributed to E J Fairchild.

15 recordsLinked to original sources
PubMed1990

Shiftwork and industrial injuries at a chemical plant in southeast Texas.

A historical retrospective study of 242 shiftworker (SW) and 224 non-SW (NSW) injuries at a chemical manufacturing plant in southeast Texas (U.S.A.) was performed. Data were collected on injuries that occurred between 1 January 1982 and 31 December 1985. The SW schedule comprised an 8-hr, 7-day backward rotation program while the dayworker schedule consisted of a typical U.S.A. 40-hr work week. Injury records were matched against payroll/attendance records to substantiate the probability of isolating possible effects of the shiftwork rotation schedule on the rates, distribution and severity of injuries. Injuries in the SW sample were compared to those in the non-SW sample. The work responsibilities of dayworkers were not exactly the same as those of shiftworkers. However, the job responsibilities for males and females within the dayworker and shiftworker groups were equivalent. Overall injury incidence rates were not significantly different between SWs and non-SWs, although female SWs had significantly higher incidence rates than did male SWs and both male and female dayworkers. The occurrence of injuries, however, was not equally distributed during the day shift and the night shift, but was equally distributed during the evening shift and for non-SWs, suggesting that certain, yet to be determined, factors were affecting the distribution of injuries during the day and night shift. However, the average number of injuries was two-three times higher during the first four days of the day and night shift, yet were not elevated during the evening shift.

Accidents, Occupational↗
PubMed1989

The influence of inhaled formaldehyde on rat lung cytochrome P450.

The effect of formaldehyde (HCHO) inhalation on total cytochrome P450 in the lungs of Sprague-Dawley rats was assessed after single and repeated exposures to 0, 0.5, 3, and 15 ppm HCHO. Whole-body exposures were conducted in dynamic, monitored exposure systems for 6 hr/day, 5 days/week, for periods of exposure of 1 day, 4 days, 12 weeks, or 24 weeks. Lung microsomal fractions were prepared and total protein and cytochrome P450 were measured 18 hr after the end of exposure at each time point. Two separate sets of exposure studies were conducted, thus duplicating all measurements for each dose group and at each time point. There were no detectable levels of total lung P450 in any of the rats that received a single 6-hr exposure to all three HCHO doses, while control lung P450 levels were similar to that found for 4-day and 12-week control rats. After 4 days of repeated exposures, however, there was a highly significant, reproducible, and dose-dependent increase in lung P450 levels relative to controls, with the 0.5, 3, and 15 ppm groups demonstrating 387, 1026, and 1123% of control values, respectively. Lung P450 levels remained elevated at all HCHO concentrations through 12 and 24 weeks of exposure, although the percentage difference between exposed and control rats continually dropped throughout the course of long-term repeated exposures. While HCHO-exposed rats did have decreased total body weight relative to controls, lung microsomal protein and lung weight of nearly all of the HCHO-exposed rats was not significantly different from the controls. The initial inactivation of lung P450 after a single HCHO exposure is apparently a transient phenomenon, with dose-dependent induction of the total P450 levels in the lung as the pattern of response to repeated exposures to inhaled HCHO.

Administration, Inhalation↗
PubMed1988

The mutagenicity of urine fractions from patients administered antineoplastic therapy.

A concern among hospital personnel is their exposure to mutagenic drugs and in the incidental exposures that could occur in caring for the patients. In a recent published study the mutagenicity of urine from patients administered antineoplastic drugs was determined and techniques were developed to chemically inactivate the mutagenicity. A question still remained as to what components of the excreted urine were mutagenic. Urine samples from patients receiving mutagenic drugs were fractionated by high pressure liquid chromatography (HPLC) to then assay by the Ames test the collected and concentrated fractions to determine what were the mutagenic compounds in the urine. Urine samples from patients on single agent cancer treatment with cisplatin, cyclophosphamide, doxorubicin and mitomycin C were assayed. In general, all urine samples containing the cytotoxic agents studied were mutagenic because of the presence of the parent compound, except cyclophosphamide which requires activation and therefore an active metabolite was the major mutagenic constituent in the urine sample. This data indicates that the mutagenicity of urine from patients receiving these antineoplastic agents is the result of the parent compound or a single major metabolite.

Antineoplastic Agents↗
PubMed1987

Stability and inactivation of mutagenic drugs and their metabolites in the urine of patients administered antineoplastic therapy.

Urine samples from patients administered mutagenic antineoplastic drugs are mutagenic in the Ames assay, and hence may pose a genotoxic hazard to hospital personnel or family members caring for the patient. The urine samples in the present study were tested for mutagenicity in several strains of Salmonella typhimurium that were uvr negative (TA98, TA100) or positive (TA102, UTH8413, UTH8414), and were analyzed for the presence of drugs and their metabolites using high-pressure liquid chromatography (HPLC). Urine samples from cancer patients were kept at room temperature and their mutagenicity as well as the chemical stability of the drugs was tested for a period of 14 days. It was observed that, in general, the urine remained mutagenic for the 14-day period while the parent compound degraded within the first seven days. An exception was cisplatin, which was chemically stable as platinum, but the urine decreased in mutagenicity with time. This decrease was probably the result of ligand exchange with the platinum. Inactivation methods were developed to reduce the genotoxic hazard posed by the mutagenic compounds in the urine. Cisplatin was inactivated by complexing with sodium diethyldithiocarbamate (DDTC). Oxidation of urine containing mitomycin C and doxorubicin (sodium thiosulfate must be added to urine containing doxorubicin) with 5.25% sodium hypochlorite solution (bleach) results in mutagenic inactivation. Urine containing cyclophosphamide and its metabolites was oxidized with alkaline potassium permaganate and the active degradation products trapped with sodium thiosulfate. Both chemical and mutagenic assays are necessary to determine the reduction of risk. Methods of inactivation of mutagenic urine developed in this study are both effective and practical for the reduction of exposure to genotoxic hazards.

Antineoplastic Agents↗
PubMed1987

Toxicologic interactions between ozone and bacterial endotoxin.

The effects of acute exposure of mice to bacterial lipopolysaccharide (LPS), the endotoxin of gram negative microorganisms, and ozone (O3) have been investigated. Intraperitoneal (ip) administration of 5 mg/kg LPS to CD-1 mice followed by exposure to 15 ppm O3 for 1.5 hr produced synergistic effects as measured by pulmonary edemagenesis and lethality assays. In contrast, ip administration of 0.1-1.6 mg/kg LPS to CD-1 mice over 5 consecutive days, a dose regimen resulting in LPS tolerance, protected against a lethal challenge of 20 ppm O3 for 3 hr. A statistically significant increase in catalase and glutathione peroxidase activity was measured in homogenates of lungs obtained from CD-1 mice receiving a tolerance-inducing regimen of LPS. These results demonstrate that two, distinct toxicologic interactions can occur between O3 and bacterial LPS. Synergism between these agents could explain, in part, the increased susceptibility of O3-exposed animals to respiratory infection with gram negative microorganisms. Protection resulting from LPS-induced increases in pulmonary antioxidant activity provides additional evidence that O3 and, possibly, LPS mediate their toxicity through oxidative mechanisms.

Animals↗
PubMed1987

Distribution of DNA and RNA content in the bone marrow and alveolar macrophages of rats after subchronic inhalation of formaldehyde.

The technique of flow cytometry was used to monitor the cell-cycle distribution of DNA and RNA in selected tissues of rats that were subchronically exposed to formaldehyde (HCHO) inhalation. Male Sprague-Dawley rats inhaled HCHO vapor concentrations of 0, 0.5, 3, or 15 ppm for 6 hr/day, 5 days/week, for up to 24 weeks. Simultaneous two-parameter measurements were made on a Phywe ICP 22 pulse cytophotometer by use of an acridine orange stain of the DNA and RNA of each cell sampled. No significant changes relative to the controls were determined in the percentage S and G2 + M phases of the DNA from sample tissues of the HCHO-exposed animals. Increases of 50 to 60% in the RNA content of G1 cells (RI) in the alveolar macrophages were seen after 1 week of exposure at all three HCHO doses. This effect was diminished after subchronic exposure. No HCHO-related effect was observed, though, in the RI of the rat bone marrow cells at any time point. However, the observed changes in RNA content were of rather limited magnitude relative to the cell-cycle perturbation induced by known cytotoxic agents in this and other flow cytometry studies. These modest and transient RI increases therefore probably did not reflect any significant effect on cell viability or cell proliferation in the affected tissues.

Administration, Inhalation↗
PubMed1987

Induction of metallothionein synthesis in human peripheral blood leukocytes.

Metallothionein (MT), a low molecular weight, metal-binding protein, has recently been shown to protect murine mononuclear phagocytic cells from the cytotoxic effects of bacterial lipopolysaccharides (LPS), the endotoxic component of Enterobacteriaceae. MT appears to function intracellularly as an antioxidant since autolysis results from lipid peroxidation initiated by free radicals of O2. Since this activity is distinct from MT's capacity to specifically sequestrate heavy metals, we examined whether MT synthesis can be induced by direct membrane activation or through interaction with soluble leukocyte mediators. Normal human monocytes, polymorphonuclear neutrophils (PMN), and lymphocytes, isolated from heparinized whole blood, were incubated with and without LPS from Escherichia coli and Salmonella typhosa. MT in cell lysates was quantitated using a 203Hg-binding assay employing Sephadex G-10 "minicolumns." When incubated with monocytes, PMN, or lymphocytes, neither preparation of LPS (10-100 micrograms/ml) was capable of enhancing 203Hg-binding activity after 24 or 72 hr incubation. CdCl2 (2 micrograms/ml), however, increased binding activity in monocyte and lymphocyte cultures 4- and 15-fold, respectively. When monocytes and lymphocytes were cocultured with LPS, 203Hg-binding activity was not enhanced. Addition of human interleukin 1 (endogenous pyrogen) to these cultures had no significant effect. Leukocyte endogenous mediator (LEM), a product of LPS-activated PMN that possesses hypozincemic activity in vivo, did not induce MT synthesis. Collectively, these results demonstrate that leukocyte MT does not arise from direct LPS activation or from interaction with products secreted by LPS-activated cells. De novo synthesis of MT observed during endotoxemia and gram negative sepsis appears, therefore, to be induced by endogenously released corticosteroids.

Adult↗
PubMed1986

Evidence for lipid peroxidation in endotoxin-poisoned mice.

Ethane has been identified and quantitated in air exhaled by mice following intraperitoneal injection of 20, 40, or 200 mg of Escherichia coli O111:B4 lipopolysaccharide (LPS) per kg. Significant increases in ethane concentration occurred within 1 to 5 h after LPS administration. In addition, increased concentrations of malondialdehyde were found in crude homogenates of livers obtained from mice 16 h after administration of 20 mg of LPS per kg. These results suggest that lipid peroxidation may be an important mechanism responsible for LPS toxicity.

Animals↗
PubMed1985

Primary irritant contact dermatitis from synthetic pyrethroid insecticide exposure.

Synthetic pyrethroids are widely used insecticides with numerous applications, varying from food protection to general pest control. Humans are capable of tolerating greater acute and chronic exposures to the pyrethroids than to many other insecticides. An abnormal cutaneous sensation (paresthesia) is known to occur after dermal contact with the pyrethroids. Recent field studies have indicated that a primary irritant contact dermatitis may also develop. This investigation evaluated dermal irritancy from cutaneous synthetic pyrethroid application to albino rabbits. Through repeated daily applications of either fenvalerate or permethrin, a slight erythema was noted visually which correlated with increased cutaneous blood flow measured by laser Doppler velocimetry. Histopathological changes were also documented, but no significant differences were detected in edema or thermal variation.

Animals↗
PubMed1985

Effect of subchronic formaldehyde inhalation on minute volume and nasal deposition in Sprague-Dawley rats.

Since respiratory depression during formaldehyde (HCHO) inhalation is an important mechanism in reducing the dose received and potentially the toxicity in the nasal passages of exposed animals, this study was conducted to determine if changes in the pattern of minute volume response and nasal deposition occurred in nosepiece challenges to rats after long-term repeated exposures to HCHO. Male Sprague-Dawley rats were exposed to 0, 0.5, 3, or 15 ppm HCHO for 6 h/d, 5 d/wk, for 8 or 16 wk. The preexposed animals and age-specific controls were then submitted to a HCHO nosepiece challenge at the same concentration that was received in the subchronic exposure. Very high nasal deposition was demonstrated in all measurements. There was a diminished maximum minute volume depression in the 16-wk group relative to the 8-wk group. The difference in response was not statistically associated with the subchronic preexposure concentration. The substantial recovery of all initially depressed responses that occurred during the challenges probably diminished the impact of the decreased maximum responses on the resulting nasal deposition over the course of the long-term exposures.

Absorption↗
PubMed1985

Synthetic pyrethroid insecticides: a dermatological evaluation.

Synthetic pyrethroids are lipophilic insecticides whose biological activity seems to be directly related to their chemical structure. In this investigation differences in cutaneous sensation were detected by human participants between synthetic pyrethroids with a cyano group in the (S)-configuration of the 3-phenoxybenzyl alcohol of their molecular structure (fenvalerate) and those that do not (permethrin). A strong relation was noted between insecticidal potency and degree of induced cutaneous sensation for the alpha-cyano and non-cyano pyrethroids, with a prominent difference between the two. No sensation was observed by any of the same participants on topical exposure to the inert ingredients of these agents. A linear correlation between concentration and degree of induced dysaethesia was observed for both pyrethroids. Regressing the cutaneous sensation on the common logarithm of concentration resulted in a regression equation of Y = 84.0 + 31.0X1 for fenvalerate and Y = 27.5 + 15.8X1 for permethrin. A highly efficacious therapeutic agent for pyrethroid exposure was noted to be dl-alpha tocopherol acetate. An impressive degree of inhibition of paraesthesia resulted from the topical application of vitamin E acetate, with a therapeutic index of almost 100%.

Dose-Response Relationship, Drug↗
PubMed1978

Occupational safety and health: United States of America.

The major legislation in the United States to implement safety and health in the workplace is the Occupational Safety and Health Act of 1970 (Public Law 91-595). The United States has enacted a number of laws to reduce the number and severity of work-related injuries and illnesses which, despite efforts of employers and government, were resulting in ever-increasing human misery and economic loss. The Act calls not only for enforcement of standards but for programmes of research, education and training. The Secretary of the Department of Labour Uniformly applies occupational safety and health standards which have been developed with the assistance of the Secretary of the Department of Health, Education and Welfare. A strong programme has been developed in research and application of research to problems in the special areas of mining, construction, and agriculture, as well as for general industry and other employment.

Accidents, Occupational↗
PubMedDate not supplied

Respiratory responses in the lower respiratory tract of Sprague-Dawley rats to formaldehyde inhalation.

This study was conducted to determine the characteristic response of Sprague-Dawley rats to formaldehyde (HCHO) challenges to the lower respiratory tract, and whether these response patterns are altered in rats that have received repeated exposures to HCHO. Male Sprague-Dawley rats were exposed to 0, 0.5, or 15 ppm HCHO for 6 hours/day, 5 days/week, for 8 or 16 weeks. Both naive rats and rats repeatedly exposed to HCHO were then administered 30 ppm HCHO test challenges by tracheal exposure, with the minute volume, respiratory rate, and tidal volume responses monitored. The pulmonary response of naive rats to HCHO tracheal challenge involved the correlation of minute volume and tidal volume depression, while respiratory rate was either unaffected or slightly increased. This was also the response pattern for rats that received 8 weeks of repeated exposure to HCHO. The only significant difference in respiratory response patterns between naive and pre-exposed animals existed in a slight increase in the respiratory rate compensatory response in the rats pre-exposed for 16 weeks to 15 ppm. There was substantial recovery of initially depressed respiratory parameters during the tracheal challenge in both naive and pre-exposed rats. The characteristic pulmonary response to HCHO in the lower respiratory tract demonstrated for Sprague-Dawley rats was thus similar to patterns of lower respiratory response to HCHO reported for other rodent species.

Animals↗