Solvents and Parkinson disease: a systematic review of toxicological and epidemiological evidence

Parkinson disease (PD) is a debilitating neurodegenerative motor disorder, with its motor symptoms largely attributable to loss of dopaminergic neurons in the substantia nigra. The causes of PD remain poorly understood, although environmental toxicants may play etiologic roles. Solvents are widespread neurotoxicants present in the workplace and ambient environment. Case reports of parkinsonism, including PD, have been associated with exposures to various solvents, most notably trichloroethylene (TCE). Animal toxicology studies have been conducted on various organic solvents, with some, including TCE, demonstrating potential for inducing nigral system damage. However, a confirmed animal model of solvent-induced PD has not been developed. Numerous epidemiologic studies have investigated potential links between solvents and PD, yielding mostly null or weak associations. An exception is a recent study of twins indicating possible etiologic relations with TCE and other chlorinated solvents, although findings were based on small numbers, and dose-response gradients were not observed. At present, there is no consistent evidence from either the toxicological or epidemiologic perspective that any specific solvent or class of solvents is a cause of PD. Future toxicological research that addresses mechanisms of nigral damage from TCE and its metabolites, with exposure routes and doses relevant to human exposures, is recommended. Improvements in epidemiologic research, especially with regard to quantitative characterization of long-term exposures to specific solvents, are needed to advance scientific knowledge on this topic.

[Analysis on the occupational poisoning case of trichloroethylene reported in Dongguan during 2002 to 2009 ]

OBJECTIVE

To understand the demographic, occupational and clinic characteristics of occupational poisoning case due to trichloroethylene in Dongguan in recent years for the purpose of prevention.

METHODS

Using the trichloroethylene patients of poisoning diagnosed in the years between 2002 to 2009 as subjects, their age, sex, industry, job, working duration and exposure level were analysed.

RESULTS

In Dongguan between 2002 and 2009 altogether 82 cases were reported, among the 82 cases 8 patients were dead with case fatality rate of 9.8%. among them there were 12 cases of poisonings(8 females ,4 males); 9 cases were classified as mild poisonings and the rest serious ones, among the 12 cases 3 patients were dead with case fatality rate of 25.0%; Dermatitis caused by TCE there were 70 cases (37 males and 33 females), among the 70 cases 5 patients were dead with case fatality rate of 7.1%. 11 persons (91.7%) were engaged in the job of cleaning and 1 (8.3%) in water gun, and they performed the job only for 3 days in shortest and for 450 days in longest. The cases were distributed in the jobs as the following: 29 (41.4%), 12 (17.1%), 8 (11.4%), 5 (7.1%), 4 (5.7%), cases respectively in the job of cleaning, parts hanging, board washing, painting, gun water spraying; a job duration of 1-50 d (27.4 days in average).

CONCLUSION

In summary the TCE poisonings in Dongguan were two types of poisoning, i.e., systematic poisonings and drug rash-like dermatitis, occupational TCE poisonings took place mainly in the cleaning workers. Dermatitis caused by TCE can cure but hard to prevent, we should strengthen the early examination of new works.

Occupational trichloroethylene exposure and renal carcinoma risk: evidence of genetic susceptibility by reductive metabolism gene variants

Trichloroethylene (TCE) is a suspected renal carcinogen. TCE-associated renal genotoxicity occurs predominantly through glutathione S-transferase (GST) conjugation and bioactivation by renal cysteine beta-lyase (CCBL1). We conducted a case-control study in Central Europe (1,097 cases and 1,476 controls) specifically designed to assess risk associated with occupational exposure to TCE through analysis of detailed job histories. All jobs were coded for organic/chlorinated solvent and TCE exposure (ever/never) as well as the frequency and intensity of exposure based on detailed occupational questionnaires, specialized questionnaires, and expert assessments. Increased risk was observed among subjects ever TCE exposed [odds ratio (OR) = 1.63; 95% confidence interval (95% CI), 1.04-2.54]. Exposure-response trends were observed among subjects above and below the median exposure [average intensity (OR = 1.38; 95% CI, 0.81-2.35; OR = 2.34; 95% CI, 1.05-5.21; P(trend) = 0.02)]. A significant association was found among TCE-exposed subjects with at least one intact GSTT1 allele (active genotype; OR = 1.88; 95% CI, 1.06-3.33) but not among subjects with two deleted alleles (null genotype; OR = 0.93; 95% CI, 0.35-2.44; P(interaction) = 0.18). Similar associations for all exposure metrics including average intensity were observed among GSTT1-active subjects (OR = 1.56; 95% CI, 0.79-3.10; OR = 2.77; 95% CI, 1.01-7.58; P(trend) = 0.02) but not among GSTT1 nulls (OR = 0.81; 95% CI, 0.24-2.72; OR = 1.16; 95% CI, 0.27-5.04; P(trend) = 1.00; P(interaction) = 0.34). Further evidence of heterogeneity was seen among TCE-exposed subjects with >or=1 minor allele of several CCBL1-tagging single nucleotide polymorphisms: rs2293968, rs2280841, rs2259043, and rs941960. These findings provide the strongest evidence to date that TCE exposure is associated with increased renal cancer risk, particularly among individuals carrying polymorphisms in genes that are important in the reductive metabolism of this chemical, and provides biological plausibility of the association in humans.

Clinical analysis of seven cases of trichloroethylene medicamentose-like dermatitis

To grasp the clinical characteristics, treatment and prognosis of trichloroethylene medicamentose-like dermatitis, seven hospitalized cases were analyzed in detail. The disease has various manifestations, among them, those accompanied by hepatitis or renal diseases are crucial. Adequate dose of corticosteroid hormone in earlier period could effectively control the patient's condition. Besides paying close attention to changes of the patient's skin, we should also keep an eye for the changes of the liver and kidneys and their relevant indices, as different patients have different prognoses.

A meta-analysis of occupational trichloroethylene exposure and liver cancer

OBJECTIVE

Findings from epidemiologic studies of trichloroethylene (TCE) exposure and liver cancer have been inconsistent. To quantitatively evaluate this association and to examine sources of heterogeneity, we conducted a meta-analysis of occupational studies of TCE exposure and liver/biliary tract cancer.

METHODS

We identified 14 occupational cohort studies of TCE exposed workers and one case-control study that met our inclusion criteria. Nine studies specifically identified TCE as a workplace exposure, and were classified as Group I cohort studies. Subcohorts of workers, identified within eight of these studies as more likely exposed to TCE than the total cohort, were analyzed separately.

RESULTS

The combined liver/biliary cancer summary relative risk estimate (SRRE) for all studies was 1.08 (95% CI 0.91-1.29; heterogeneity (H)-P-value=0.12). For the total study populations in the Group I cohorts, the SRRE was 1.14 (95% CI 0.93-1.39; H-P-value=0.05) and for the subcohorts, the SRRE was 1.30 (95% CI 1.09-1.55). Within this subcohort analysis, the association for the European studies of workers from various industries (SRRE=1.38; based on four studies) was higher than the association for the US studies of aerospace and aircraft workers (SRRE=0.97, based on four studies).

CONCLUSION

Although positive associations were observed for some analyses, results were inconsistent across occupational groups (aerospace/aircraft vs. other industries combined), study location, and incidence versus mortality endpoints. In addition, exposure-response trends were not observed consistently across studies. Interpretation is also limited by the potential impact of uncontrolled confounding by other occupational or lifestyle exposures such as smoking or alcohol consumption. Given these limitations, the currently available epidemiologic data are not sufficient to support a causal relation between occupational TCE exposure and liver/biliary cancer.

Acute, nonfatal intoxication with trichloroethylene

Nonfatal acute inhalation of trichloroethylene (TRI) at work was described. The subject, male, 54 years old, was drawn unconscious by a metal-degreasing machine and immediately sheltered in intensive care unit. Other than basic life support and common laboratory indices, blood and urine were collected to measure dose and kidney effect parameters such as TRI in blood and urine, trichloroethanol (TCE) and trichloroacetic acid (TCA) in urine, and total urinary proteins (TUP), urinary glutamine synthetase (GS) and urinary N-acetyl-beta-D-glucosaminidase (NAG). Two hours after accident, TRI in blood was 9 mg/l, but after 38 h it was below 1 mg/l. TCE and TCA have a peak 11 and 62 h after poisoning, respectively. Acute renal involvement was revealed by a peak of urinary proteins and enzymes 7 h after exposure with a second peak 74 h after. Seven day after hospitalisation the patient was dismissed with complete recovery. This nonfatal intoxication with TRI shows that the exposure was approximately 150 ppm, three times the ACGIH TLV (50 ppm) and that kidney was the only organ affected. Urinary enzymes, in particular GS, are good indices to monitor transient effects of TRI on the kidney.

[Acute intoxication with trichloroethylene--a case report]

In a study the case of an acute intoxication following inhalant abuse of trichloroethylene vapours is presented. Narcotic effects lasting for 48 hours after exposure were seen. The patient complained of strong, polyneuropathic lower legs and feet pain lasting for 7 days. Urinary trichloroacetic acid (TCA) was monitoring. Peak urine TCA concentration reached 840 mg/L on 4 day after exposure.

Crises temporales symptomatiques d’une intoxication au trichloroéthylène

INTRODUCTION

Trichloroethylene (TCE) is extensively used as a degreasing agent in the metal industry and as a solvent for organic compounds. Its neurotoxicity (with respect to both the peripheral and central nervous systems) is now widely acknowledged.

OBSERVATION

Here, we report the case of a 32-year-old male drug addict presenting temporal seizures after "huffing" TCE (i.e. voluntary inhalation). The patient also deve loped a "psycho-organic syndrome" which included cognitive dysfunction (with memory disorders in particular) and personality changes. These disorders had not been noticed by the patient's wife prior to the last episode of inhalation. Four months later, the cognitive disorders had stabilized and no further seizures had been observed.

CONCLUSION

The patient's overall clinical picture (notably featuring neuropsychological disorders) and electroencephalographic and brain imaging data argue in favor of a selective effect of TCE on the temporal lobe.

[Psychiatric patient with elevated liver values]

Bei unklaren Leberwerterhöhungen, besonders wenn Therapien mit verschiedenen potentiell hepatotoxischen Medikamenten bestehen, muss an eine medikamentöse Ursache gedacht werden. In unserem Fall konnte diese weitgehend ausgeschlossen werden. Eine Leberwerterhöhung nach Therapie mit Amoxicillin und Clavulansäure betrifft vorrangig cholestatische Enzyme und kommt bis zu sechs Wochen nach Therapie vor, während bei Clozapin Bilirubin und alkalische Phosphatase eher nicht betroffen sind. Die Hepatotoxizität von Trichlorethylen tritt unmittelbar nach der Ingestion auf. Durch diese differentialdiagnostischen Überlegungen und den Nachweis einer Cholezysto- und Choledocholithiasis konnte somit eine Ursache gefunden und die Indikation zur Operation beziehungsweise ERCP gestellt werden.

ATSDR's trichloroethylene subregistry methods and results: 1989-2000

The National Exposure Registry of the Agency for Toxic Substances and Disease Registry (ATSDR) uses standard methods to study human exposure in four chemical subregistries: trichloroethylene (TCE), dioxin, benzene, and trichloroethane. The TCE Subregistry includes a baseline cohort of 4006 white registrants with drinking water exposure in Michigan, Indiana, Illinois, Pennsylvania, and Arizona. Between 3 and 6 follow-ups per site were conducted from 1989 to 2000, after baseline. Standardized morbidity ratios, controlling for age and sex, compared prevalences of 16 general health conditions in the subregistry with aggregated national estimates from the 1989-1994 National Health Interview surveys. Excess cases of dermatologic, hematologic, or hepatic disorders and strokes persisted over the lifetime of the registry. Persistent excess urinary tract disorders are likely caused by a systematic bias. This review of first-generation methods may be used to strengthen future exposure registries.

VHL mutations in renal cell cancer: does occupational exposure to trichloroethylene make a difference?

Occupational exposures have long been suspected to play a role in the incidence of renal cell carcinoma (RCC). Especially, the carcinogenicity of the industrial solvent trichloroethylene (TCE) has been controversially debated, both with respect to the epidemiological and the molecular studies. In order to further elucidate this issue, it appeared important to compare suitable RCC patient groups, i.e., TCE-exposed versus non-TCE-exposed patients. We evaluated RCC from a previous German study that had described differences in RCC risks between TCE-exposed (n=17) and non-exposed patients (n=21). We compared age at diagnosis and histopathologic parameters of tumors as well as somatic mutation characteristics in the kidney cancer causing VHL tumor suppressor gene. RCC did not differ with respect to histopathological characteristics in both patient groups. We noticed a younger age at diagnosis in TCE-exposed patients compared to non-exposed patients (P=0.01). Moreover, the non-TCE-exposed patients did not share the somatic VHL mutation characteristics of TCE-exposed patients such as the previously identified hot spot mutation 454 C > T P81S or multiple mutations. These data support the notion of a putative genotoxic effect of TCE leading to VHL gene damage and subsequent occurrence of RCC in highly exposed subjects.

Male Reproductive Toxicity of Trichloroethylene: Sperm Protein Oxidation and Decreased Fertilizing Ability1

The objective of the present study was to characterize and investigate potential mechanisms for the male reproductive toxicity of trichloroethylene (TCE). Male rats exposed to TCE in drinking water exhibited a dose-dependent decrease in the ability to fertilize oocytes from untreated females. This reduction in fertilizing ability occurred in the absence of treatment-related changes in combined testes/epididymides weight, sperm concentration, or sperm motility. In addition, flow cytometric analysis showed that there were no treatment-related differences in sperm mitochondrial membrane potential or acrosomal stability. TCE caused slight histological changes in efferent ductule epithelium, coinciding with the previously reported ductule localization of cytochrome P450 2E1. However, no alterations were noted in the testis or in any segment of the epididymis. Because there were no treatment-related changes to sperm indices and no clear pathological lesions to explain the reduced fertilization, the present study investigated TCE-mediated sperm oxidative damage. Oxidized proteins were detected by immunochemical techniques following the derivatization of sperm protein carbonyls with dinitrophenyl hydrazine. Immunochemical staining of whole, intact sperm showed the presence of halos of oxidized proteins around the head and midpiece of sperm from TCE-treated animals. The presence of oxidized sperm proteins was confirmed by Western blotting using in vitro-oxidized sperm as a positive control. Thiobarbituric acid reactive substances analyses showed a dose-dependent increase in the level of lipid peroxidation in sperm from treated animals, as well. Oxidative damage to sperm may explain the diminished fertilizing capacity of exposed animals and provide another mechanism by which TCE can adversely affect reproductive capabilities in the male.

Tissue distribution of trichloroethylene in a case of accidental acute intoxication by inhalation

This article describes the toxicological findings in a fatality due to an accidental inhalation of trichloroethylene which took place during wall coating of a poorly ventilated well using trichloroethylene. The man was wearing protective clothing and a mouthmask with adsorbent. He was found dead on the floor of the well 5h after descending. Trichloroethylene was added to the mortar to enhance drying. Identification and quantitation of trichloroethylene in the postmortem samples (blood, lung, liver, kidney, stomach content and bile) and identification of its metabolite trichloroacetic acid in urine was performed using static headspace gas chromatography with mass spectrometric detector. The compounds were separated on a CP-SIL 5CB Low Bleed/MS column using n-butanol as internal standard. The method was linear over the specific range investigated, and showed an accuracy of 104% and an intra-day precision of 11%. Trichloroethylene concentrations of 84mg/l in subclavian blood, 40mg/l in femoral blood, 72mg/kg in liver, 12mg/kg in kidney, 78mg/kg in stomach content, 104mg/l in bile and 21mg/kg in lung were found. Trichloroacetic acid was identified in the urine.

Do duration of exposure, proximity to electronic manufacturing plants, and involvement in a lawsuit affect chlorinated solvent toxicity?

The author examined the effects of duration of residence, proximity to microchip plants, and being a party in litigation involving neurobehavioral functioning in individuals who had been chronically exposed to trichloroethylene-associated solvents from the environment. The author compared duration of exposure for the 236 residents, all of whom were located in 3 proximity zones in Phoenix, Arizona; some of the individuals had been in the process of solvent-related litigation for fewer than 10 yr, whereas some had been involved for more than 10 yr. The 236 residents were compared with 58 nonclaimants in 3 residential areas within the exposure zones. Neurobehavioral function testing was described in the study that appears prior to this study in this issue. Prior to comparisons, test scores were adjusted for age, sex, education level, and other significant factors. Individuals who had been exposed for fewer than 10 yr were not different from individuals who had been exposed for longer periods. Proximity to microchip plants produced no statistically significant effects. Among the 169 exposed subjects (i.e., exposure for 15 yr to trichloroethylene-associated solvents), of whom some were parties in lawsuits, those who lived in the near west area (Zone A) of Phoenix did not differ with respect to results of the 14 neurobehavioral tests that were administered. However, Zone B subjects, located to the north of the plant, differed with respect to 2 of the tests; and Zone C subjects, located beyond Zone A, Phoenix, differed with respect to 3 of the tests. In conclusion, duration of residence, proximity to microchip plants, and being a party to a lawsuit had no significant effects on neurobehavioral functioning, but, in this study, parties in the lawsuit were subjects who experienced more frequent symptoms.

Is neurotoxicity associated with environmental trichloroethylene (TCE)?

Individuals who lived near 2 electronic manufacturing plants were exposed to odorous chlorinated solvents by inhalation (directly) and by out gassing from well water. An exposure zone was defined by concentrations of trichloroethylene, 1,1,1-trichloroethane, tetrachloroethylene, and vinyl chloride in groundwater. The author adopted trichloroethylene as a "shorthand" for the exposure designation. Residents complained of impaired recall and concentration, and of dizziness; therefore, the focus of this investigation was brain functions. Neurobehavioral functions, Profile of Mood States, frequencies of 35 symptoms, and questionnaire responses provided by 236 residents from exposure zones were compared with responses provided by 161 unexposed regional referents and by 67 Phoenix residents who lived outside the exposure zone areas. Pulmonary functions were measured with spirometry. Residents of the exposure zones were compared with regional referents, and the former had significantly (p < .05) delayed simple and choice reaction times, impaired balance, delayed blink reflex latency R-1, and abnormal color discrimination. In addition, these individuals had impaired (1) cognitive functions, (2) attention and perceptual motor speed, and (3) recall. Individuals who lived in exposure zones had airway obstructions. Adverse mood state scores and frequencies of 33 of 35 symptoms were elevated. In conclusion, individuals who lived in the exposure zones had neurobehavioral impairments, reduced pulmonary functions, elevated Profile of Mood State scores, and excessive symptom frequencies.

An unusual presentation of inhalant abuse with dissociative amnesia

A 38-y-old male with occult inhalant abuse underwent an 18-mo evaluation for presumed seizure disorder. Although past medical history was significant for alcohol abuse, his wife confirmed a 6-y histoy of abstinence. His seizures were characterized as episodes of unconsciousness preceded by a feeling of "things slowing down". No muscular activity was witnessed during these episodes, and upon regaining consciousness the patient had slurred speech, disorientation, dissociative amnesia, and bizarre behavior that resolved spontaneously. Despite 4 emergency department visits, 4 hospital admissions, 5 neurologic and 7 psychiatric outpatient evaluations, extensive work-up was non-diagnostic. These episodes recurred until his wife found him huffing trichloroethylene. Questioning of the patient revealed that huffing always preceded these episodes and that he started huffing after discontinuing alcohol. The patient underwent addiction treatment. Toxic inhalants should be suspected as a substitute drug of abuse in patients attempting abstention. Disorientation clinically similar to dissociative amnesia can occur following loss of consciousness during an episode of trichloroethylene use.

Tetrachloroethylene and trichloroethylene fatality: case report and simple headspace SPME-capillary gas chromatographic determination in tissues

We describe a simple, precise, and sensitive assay of tetrachloroethylene and trichloroethylene in tissues, suitable both for emergency cases and forensic medicine. The method employs headspace solid phase microextraction-capillary gas chromatography and electron capture detection. The case is relative to a 45-year-old woman discovered unconscious in a laundry area. The concentrations of the solvents in tissues were determined and compared to other previously published fatalities.

Acute intoxication with trichloroethene: clinical symptoms, toxicokinetics, metabolism, and development of biochemical parameters for renal damage

The present study reports on a 17-year-old male who ingested approximately 70 ml trichloroethene (TRI) in a suicide attempt. The patient developed fever, tremor, general motor restlessness, and sinus tachycardia and lost consciousness 5 h after poisoning. After 5 days of intubation under narcosis with forced hyperventilation and diuresis he regained consciousness. During this period blood and urine were collected and TRI and its metabolites were quantified. The highest concentration of TRI in blood was detected 13 h after ingestion. Trichloroethanol and trichloroacetic acid, metabolites of the cytochrome P450-mediated pathway, and N-acetyl-S-(1, 2-dichlorovinyl)-l-cysteine and N-acetyl-S-(2, 2-dichlorovinyl)-l-cysteine from the glutathione-dependent pathway of TRI were quantified in urine samples. Besides these known metabolites in humans, chloroacetic acid and dichloroacetic acid were identified for the first time in urine of a human exposed to TRI. Although the patient exhibited normal levels of glucose and total protein in urine, excretion of alpha1- and beta2-microglobulin as well as beta-NAG was significantly increased. In addition to these typical markers of selective tubule damage, analysis of the urinary protein pattern by SDS-PAGE revealed increased excretion of several low-molecular-mass proteins between 10,000 and 50,000 Da, clearly indicating tubular damage. Based on the elucidated glutathione-dependent mechanism for the nephrotoxicity of TRI, activation of the formed S-conjugates by beta-lyases to reactive intermediates may account for the observed renal effects after a single, high dose of TRI.

Tissue distribution of trichloroethylene and its metabolites in a forensic case

A fatality that was due to the ingestion of the halogenated solvent trichloroethylene is presented. The decedent was a 43-year-old male who was found dead at his home. Screening of the blood and stomach contents with the enzyme multiplied immunoassay technique and radioimmunoassay demonstrated the presence of ethanol, amphetamine-like compounds, caffeine, cotinine, and acetaminophen. These compounds were present in toxicologically irrelevant concentrations as confirmed by thin-layer chromatography, high-performance liquid chromatography, and gas chromatography (GC). The Fujiwara reaction was performed on all available matrices, and it revealed the presence of chlorinated hydrocarbons in high concentrations. A specific GC method with electron capture detection allowed the quantitation of trichloroethylene and its metabolites trichloroethanol and trichloroacetic acid in different matrices. GC with Fourier-transform infrared detection was used for the confirmation of the identity of trichloroethylene.

Hazardous waste and neurobehavioral effects: a developmental perspective

This paper summarizes the findings gleaned from detailed clinical examinations of three groups of residents who were exposed to trichloroethylene in well water. Also summarized are diagnostic findings for peripheral neuropathy. A detailed description of the neuropsychological test results is included, as well as a summary of domain-specific findings and diagnostic outcomes. A high rate of cognitive deficits of the type seen in patients with central nervous system dysfunction attributable to solvent exposure was seen. In addition, there was a clear developmental trend: subjects who were younger at the time of TCE exposure showed deficits in a larger variety of cognitive realms than did subjects who had already reached adulthood by the time of exposure. In particular, language deficits were seen in the younger, but not older, exposed subjects.

[The pathogenesis, clinical picture and treatment of poisonings by organic solvents, derivatives of chlorinated hydrocarbons (trichloroethylene, carbon tetrachloride)]

Clinical studies and experiments on laboratory animals covered mechanism of trichloroethylene toxicity. The chemical and its metabolites cause nonspecific toxic effects in membranes and therefore induce energy metabolism disorder that is proved to be a trigger of pathologic process in the intoxication. Experimental studies failed to disclose and explain mechanism of compromised calcium metabolism and its role in cardiac manifestations seen in trichloroethylene poisoning.

Encephalopathy and cranial nerve palsies caused by intentional trichloroethylene inhalation

This report describes an acute intentional trichloroethylene exposure that developed neurological and cardiovascular toxicity. The patient presented with palsies of the third, fifth, and sixth cranial nerves. Clinical manifestations, laboratory values, and treatment plans are discussed. Emergency physicians should be aware of the complications of trichloroethylene exposure and consider the diagnosis in patients with similar symptoms.

Concentrations of trichloroethylene and its metabolites in blood and urine after acute poisoning by ingestion

A 58-year-old man fell into a trichloroethylene reservoir bath head first, during a maintenance degreasing bath and accidentally ingested the solvent. Although he showed deep coma, chemical burns and pneumonia on admission, these symptoms gradually subsided. The concentrations of trichloroethylene (TRI) and its metabolites, trichloroethanol (TCE) and trichloroacetic acid (TCA) in blood and urine were measured during hospitalization. Eight hours after the accident, the concentrations of TRI and its metabolites in serum were 31.4 micrograms/ml TRI, 16.5 micrograms/ml TCE and 79.5 micrograms/ml TCA. The serum TRI concentration decreased to 4.3 micrograms/ml on the following day. Elimination of TCE and TCA from serum occurred biphasically, the estimated half-lives of each metabolites being about 52.6 and 50.4 h in an initial fast phase and 268.3 and 277.2 h in a subsequent slow phase, respectively. Urinary TRI excretion persisted for the first 2 days. The urinary TCE and TCA excretions were longer than that of TRI with a biphasic decrease and the total amount of TCE excreted during the first 2 days was about two times that of TCA. The half-life of urinary TCE excretion (t1/2 25.7 h) was shorter than that of TCA (t1/2 52.1 h) in the fast phase but did no difference during the slow phase, with each half-time being about 166.3 h. The kinetics of TRI metabolites in blood and urine in this case were in slight agreement with the results following inhalation exposure previously reported in the literature.

Hepatitis, rash and eosinophilia following trichloroethylene exposure: a case report and speculation on mechanistic similarity to halothane induced hepatitis

CASE REPORT

A previously healthy 30-year-old male began work as a degreaser. The solvent used in the degreasing operation was trichloroethylene. Over the next month he experienced symptoms of weakness, dizziness, decreased appetite, nausea, abdominal pain, diarrhea, fever, chills, dry skin, red rash with bumps, peeling face, and itching. At that time he had marked liver enzyme elevation without evidence of cholestasis. CBC was remarkable for a significant number of atypical lymphocytes. Two weeks later his liver enzymes showed a marked reduction in ALT from a peak of 1250 IU to 717 IU. Tests for Hepatitis A, B, and C, CMV, HIV1 were all negative. The night following his first day back at work he had a recurrence of a red, diffuse rash without any consumption of alcohol. The rash caused tremendous itching. Over the next few days off work the rash continued and peeled. Physical examination one week after re-exposure was remarkable for diffuse, erythematous rash; some peeling skin and pitting edema to the knees. ALT was 517 IU/L. White blood cell count was 10,100/mm3 with 27% eosinophilia.

CONCLUSION

This patient had possibly experienced sensitization to trichloroethylene, or more likely, to one of its metabolites. Similar symptoms attributed to trichloroethylene have been reported in only a few other patients. Patch testing with trichloroethylene and its metabolites may better clarify a causal relationship in future patients. If an immune mechanism is involved it may be similar to one postulated for halothane induced hepatitis.

Deaths from acute exposure to trichloroethylene

Trichloroethylene (TCE) is a commonly used halogenated hydrocarbon in industry. We report on deaths attributed to TCE exposure that occurred between 1975 and 1992. In addition, we present a case report from the most recent death, including tissue concentration modeling. The deaths shared a number of features. All occurred in young men who were usually working in confined spaces without adequate ventilation. These preventable deaths suggest that safety precautions are not being observed by workers and employers. Employers should ensure that their employees are adequately trained in the dangers of working with TCE, that adequate ventilation of the working environment is provided, that the proper personal protective equipment (PPE) is available to their workers, and that workers should not work alone or unobserved when using TCE in confined spaces.

Occupational exposure to chlorinated aliphatic hydrocarbons and risk of astrocytic brain cancer

Chlorinated aliphatic hydrocarbons (CAHs) were evaluated as potential risk factors for astrocytic brain tumors. Job-exposure matrices for six individual CAHs and for the general class of organic solvents were applied to data from a case-control study of brain cancer among white men. The matrices indicated whether the CAHs were likely to have been used in each industry and occupation by decade (1920-1980), and provided estimates of probability and intensity of exposure for "exposed" industries and occupations. Cumulative exposure indices were calculated for each subject. Associations of astrocytic brain cancer were observed with likely exposure to carbon tetrachloride, methylene chloride, tetrachloroethylene, and trichloroethylene, but were strongest for methylene chloride. Exposure to chloroform or methyl chloroform showed little indication of an association with brain cancer. Risk of astrocytic brain tumors increased with probability and average intensity of exposure, and with duration of employment in jobs considered exposed to methylene chloride, but not with a cumulative exposure score. These trends could not be explained by exposures to the other solvents.

Trichloroethylene exposure in vapour degreasing and the urinary excretion of N-acetyl-beta-D-glucosaminidase

In order to elucidate the potential nephrotoxicity of low level occupational exposure to trichloroethylene (TRI), urine analysis of the tubular enzyme N-acetyl-beta-D-glucosaminidase (U-NAG) was included in a cross-sectional study of metal degreasers in central Sweden. Eighty-six percent of 8-h TRI in air measurements were well below 50 mg/m3. Normal levels of NAG were found in morning urine samples from 29 workers compared to a historical reference group. A weak positive correlation (r = 0.48; P < 0.01) was observed between U-NAG activity and the concentration of the TRI metabolite trichloroacetic acid in urine but not with other estimates of recent or long-term exposure. In conclusion, TRI does not seem to be nephrotoxic at low exposure levels.

Kinetics of trichloroethylene elimination from venous blood after acute inhalation poisoning

The kinetics of trichloroethylene were examined in three men, 28-36 years old, hospitalized after an acute occupational exposure. The trichloroethylene concentration of venous blood was determined by gas chromatography with headspace analysis; urinary trichloroacetic acid was assayed by the colorimetric method of Fujiwara. The kinetics of blood trichlorethylene (t1/2 21.7 h) and the urinary elimination of trichloracetic acid over six days were used to calculate the total inhalation exposures. Blood trichlorethylene was diagnostically more relevant than urinary trichloracetic acid.

[Trigeminal somatosensory evoked potentials in workers handling trichloroethylene]

Trigeminal somatosensory evoked potentials (TSEP) were studied in 33 workers manipulating trichlorethylene for 3 to 22 years and in 33 control subjects. A significant excessive latency delay of N13, P17 and N45 waves in workers was found. Evoked potential abnormalities found in 15 exposed subjects (45%) were as following: excessive latency delay in 9 cases (27%), decrease of amplitude in 2 cases (6%) and asymmetrical responses in 4 cases (12%). Among 5 workers (15%) presenting clinical abnormalities of trigeminal nerve impairment, only one had normal evoked potential. TSEP were altered in 11 workers (33%) who had no clinical impairment. We suggest that TSEP should be confirm trigeminal impairment in chronic cases of workers exposed to carbon tetrachloride and to predict infraclinic lesions.

Acute trichloroethylene poisoning by ingestion: clinical and pharmacokinetic aspects

Five hours after ingestion of an unknown amount of trichloroethylene (TCE) a 32-year-old woman was admitted to hospital in deep coma. The neurological condition remained unchanged for 3 days, after which there was an improvement of the central nervous system function. The concentrations of TCE in the blood, which were measured during 7 days after the solvent ingestion, gave us the opportunity to study some toxicokinetic parameters of TCE. Using a physiologically based pharmacokinetic model, the toxicokinetic parameters and blood concentrations of TCE are discussed in relation to the neurological conditions. Moreover the same model has suggested that the alveolar hyperventilation during the first 12 h following the TCE poisoning is the only treatment which may shorten the duration of the poisoning.