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Adsorption of dyes and phenols from water on the activated carbons prepared from corncob wastes.

Pore structures and physical properties of the activated carbons prepared from corncob wastes at various activation temperatures (830, 860, 890 degrees C.) were first studied. Equilibria and rates of adsorption of two commercial dyes, phenol, and 3-chlorophenol from water on such activated carbons were then measured at 30 degrees C. All adsorption isotherms of the solutes could be well fitted by the Langmuir equation. Three simplified kinetic models including pseudo-first-order equation, pseudo-second-order equation, and intraparticle diffusion model were selected to follow the adsorption processes. It was shown that the adsorption of both phenols could be best described by the pseudo second-order equation, but that of both dyes best by the intraparticle diffusion model. Kinetic parameters of each best-fit model were calculated and discussed.

Adsorption↗

Fungal diversity and use in decomposition of environmental pollutants.

This article presents a critical review of the actual state of fungal activities on environmental pollutants, fungal diversity, the use of fungi in the degradation of chemical pollutants, enzyme degrading systems and perspectives on the use of fungi in bioremediation and unexplored research. The ability of fungi to transform or metabolize chemical pollutants has received much attention due to environmental persistence and chemical toxicity. The fungal degradation of xenobiotics is looked upon as an effective method of removing these pollutants from the environment by a process which is currently known as bioremediation. This review summarizes information from fundamental works that have revealed that a wide variety of fungi are capable of degrading an equally wide range of toxical chemical. The capacity of non-ligninolytic and ligninolytic fungi in the bioremediation of polycyclic aromatic hydrocarbon (PAHs), benzene-toluene-ethylbenzene-xylene (BTEX), chlorophenols, polychlorinated biphenyl, munitions waste and pesticides have been discussed. Besides this, several extracellular enzymes are involved in the metabolism of xenobiotic compounds as well as other factors related to these processes.

Benzene Derivatives↗

Systematics and environmental application of the genus Trichoderma.

Trichoderma, an anamorphic Hypocreaceae (class Ascomycetes), is common in the environment, especially in soils. Species of this genus have been used in the production of cellulolytic and hemicellulolytic enzymes, biological control of plant disease, biodegradation of chlorophenolic compounds, and soil bioremediation. They are also the cause of disease in commercially produced mushrooms. The species Trichoderma has not been clearly defined yet, despite being a very common fungus with an expanding number of applications. Therefore, we highlight the importance of the use of molecular techninques along with conventional methodologies based on morphological characters in order to achieve a "natural" taxonomic system for this group of fungi, as well as for any other complex group of fungi.

Biodegradation, Environmental↗

Health impact of polychlorinated dibenzo-p-dioxins: a critical review.

Polychlorinated dibenzo-p-dioxins (PCDDs), commonly known as dioxins, form as unwanted impurities in the manufacturing of chlorophenol and its derivatives--pulp and paper--and in the combustion of municipal, sewage-sludge, hospital, and hazardous waste. Combustion, in presence of a chlorine donor, seems to be a major source of these compounds. High levels of dioxins are also emitted from metallurgical industries including copper smelters, electric furnaces in steel mills, and wire reclamation incinerators. Trace levels are detectable in emissions from motor vehicles using leaded gasoline or diesel fuel, in forest fires, and in residential wood burning. Extremely persistent and widely distributed in the environment, PCDDs have been detected in all three primary and many secondary media. Releases into the air occur mainly from combustor emissions. Atmospheric dispersion, deposition, and subsequent accumulation in the food chain seem to be the major pathways of exposure to the general population. Residues of these chemicals have been detected in soil, sediment, fish, meat, cow's milk, human adipose tissue, and mothers' milk. In general, these chemicals have high lipophilicity. The elimination half-life of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in humans is approximately 7-11 years. Very little human toxicity data from exposure to PCDDs are available. Health-effect data obtained from occupational settings in humans are based on exposure to chemicals contaminated with TCDD. It produces a spectrum of toxic effects in animals and is one of the most toxic chemicals known. Most of the toxicity data available on TCDD are from high-dose oral exposures to animals. Very few percutaneous and no inhalation exposure data are available in the literature. There is a wide range of difference in sensitivity to PCDD lethality in animals. The signs and symptoms of poisoning with chemicals contaminated with TCDD in humans are analogous to those observed in animals. Dioxin exposures to humans are associated with increased risk of severe skin lesions such as chloracne and hyperpigmentation, altered liver function and lipid metabolism, general weakness associated with drastic weight loss, changes in activities of various liver enzymes, depression of the immune system, and endocrine- and nervous-system abnormalities. It is a potent teratogenic and fetotoxic chemical in animals. A very potent promoter in rat liver carcinogenesis, TCDD also causes cancers of the liver and other organs in animals. Populations occupationally or accidentally exposed to chemicals contaminated with dioxin have increased incidences of soft-tissue sarcoma and non-Hodgkin's lymphoma. No comprehensive studies have been conducted to determine any health impact to the general population from environmental exposure to PCDDs. This paper presents a brief review of relevant animal and human data for projecting any possible health effects from environmental exposures to PCDDs.

Animals↗

A comparison of two methods for fractionating complex mixtures in preparation for toxicity analysis.

Chemical fractionation is a widely used tool for the chemical and toxicological characterization of complex mixtures. The objective of this research was to compare two frequently employed methods for fractionating a wood preserving waste (WPW) containing polycyclic aromatic hydrocarbons (PAHs) and pentachlorophenol (PCP). The first method involved fractionation of the WPW into acid, base, and neutral fractions using a liquid-liquid acid/base/neutral (A/B/N) technique. The second method utilized alumina column chromatography to produce two fractions, A1 and A2. Gas chromatography and mass spectrometry were used to quantify the chemical components in all fractions. The alumina method recovered 473,338 mg of total PAHs (tPAHs) per kilogram crude, while the A/B/N method yielded only 193,379 mg tPAHs/kg crude. In contrast, the A/B/N method recovered 13.7 mg PCP/kg crude while the alumina method yielded only 0.5 mg PCP/kg crude. Three bioassays were used to determine the toxicity of the crude extract and fractions. The neutral and A1 fractions contained the highest levels of tPAHs and benzo[a]pyrene (BaP) but failed to induce a positive response in the Salmonella/microsome assay with concentrations containing as much as 1800 and 2500 ng BaP/plate, respectively. In the Escherichia coli prophage induction assay, the acid fraction, which contained 472 mg PCP/kg fraction, induced a positive response, as did the base fraction, which did not contain detectable PCP. Significant reduction of gap junctional intercellular communication in hepatic cells occurred with the crude extract and acid, base, and neutral fractions. Overall, the results of these bioassays suggest that PCP genotoxicity was expressed in the acid fraction, whereas the cumulative genotoxicity of genotoxic PAHs appeared to be masked in the isolates from either fractionation method. The optimal fractionation method for a mixture of chlorophenols and PAHs may involve a refined hybrid method.

Animals↗

Effect of hydroxychlorodiphenyl ethers (chlorinated pre-and isopredioxins) on erythrocyte membrane adenosinetriphosphatase activity.

The effect of hydroxychlorodiphenyl ethers (HO-ClX-DPEs; chlorinated pre- and isopredibenzodioxins), contaminants of technical chlorophenol preparations, on human erythrocyte membrane-bound adenosinetriphosphatases (ATPases) has been investigated. Both 2- and 3-HO-Cl9-DPE inhibited the Na+ + K+-activated, Mg2+-dependent ATPase (Na+, K+, Mg2+-ATPase). The Mg2+-dependent ATPase (Mg2+-ATPase) was stimulated at lower concentration of these compounds, but at higher concentrations there was a gradual decrease in the extent of stimulation, 2-Hydroxy-21, 41, 41-trichlorodiphenyl ether (2-HO-Cl3-DPE; Irgasan DP-300; Triclosan) was not as effective as the nonachloro compounds at inhibiting Na+, K+, Mg2+-ATPase and was inactive at stimulating Mg2+-ATPase. Pure pentachlorophenol (PCP) caused both inhibition of Na+, K+, Mg2+-ATPase and stimulation of Mg2+-ATPase, although each effect required a higher concentration of PCP than was needed for the HO-CL9-DPEs. The possible relationship of the effects of HO-CL x-DPEs on human erythrocyte membrane ATPase activities to the potent hemolytic activity of these compounds is discussed.

Adenosine Triphosphatases↗

Effects of chlorinated bisphenols on torula yeast glucose-6-phosphate dehydrogenase.

Chlorinated bisphenol antibacterial and antifungal agents are potent inhibitors of torula yeast glucose-6-phosphate dehydrogenase (G6PD). Several compounds were tested, including hexachlorophene [HCP; 2,2'-methylenebis(3,4,6-trichlorophenol)]; 2,2'-oxybis(tetrachlorophenol); 2',4-dihydroxy-2,3,3',5,5',6-hexachlorodiphenylmethane; 2,2'-methylenebis(3,4-dichlorophenol) (3,4-TCP); bithionol [2,2'-thiobis(4,6-dichlorophenol)]; 2,2'-methylenebis(3,5-dichlorophenol); 2,2'-dihydroxy-3,3',5,6,6'-pentachlorodiphenylmethane; 2,2'-methylenebis(4-chlorophenol) (DCP); 2,2'-methylenebis(4,6-dichlorophenol); and the related uncoupler 2,4-dinitrophenol. The relative inhibitory activity of the chlorinated bisphenols tended to increase with degree of chlorination of the aromatic rings. the concentrations of the bisphenols that caused 50% inhibition ranged from 2.5 micrometers for 2,2'-oxybis(tetrachlorophenol) to 40 micrometers for 2,2'-methylenebis(4,6-dichlorophenol) under comparable assay conditions. More detailed kinetic analysis showed that, as with HCP, the inhibition of G6PD by 3,4-TCP and DCP followed noncompetitive kinetics. Calculations from the kinetic data gave apparent inhibition constant (Ki) values for 3,4-TCP of 267 micrometers with G6P and 308 micrometers with NADP, and for DCP of 697 micrometers with both G6P and NADP.

Anti-Infective Agents↗

A comparison of organochlorine residues in human adipose tissue autopsy samples from two Ontario municipalities.

Human adipose tissue samples obtained during autopsies in a Canadian Great Lakes community, Kingston, Ontario, and a second community, Ottawa, Ontario, were analyzed for organochlorine pesticides, polychlorobiphenyls, chlorobenzenes, and chlorophenols. Significantly different levels of Dichlorodiphenyl -dichloroethane, mirex, hexachlorobenzene, and 2,3,4,6-tetrachlorophenol were found in Kingston adipose tissues compared to Ottawa tissues. Residue levels of oxychlordane , mirex, and polychlorinated biphenyls were significantly different in Kingston males versus Kingston females. The means and ranges of residue levels were contrasted with those reported in previous Canadian surveys.

Adipose Tissue↗

A proposed occupational exposure limit for 2,3,7,8-tetrachlorodibenzo-p-dioxin.

One contaminant produced unintentionally during the manufacture of chlorophenols and phenoxy herbicides is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The resulting TCDD-containing wastes have been detected at many hazardous waste sites which in recent years have been in the process of remediation. Concerns about worker exposure to TCDD-contaminated soil (dust) during remediation of hazardous waste sites have produced a need for an occupational exposure limit (OEL) for TCDD. The animal toxicology data and human experience with TCDD are reviewed, and an occupational exposure limit for TCDD is proposed. The animal data support risk estimations which are based on TCDD as a nongenotoxic carcinogen. Studies on human populations have failed to demonstrate clearly any significant long-term health effects at levels to which humans have been exposed. The data indicate that an 8-hr time-weighted average limit of 2 ng/m3 is appropriate, and the associated risk would be consistent with other carcinogens at their corresponding OELs. A preliminary OEL of 0.2 ng/m3 (200 pg/m3) is recommended, however, in light of other sources of exposure because of TCDD's ubiquitousness in the environment, its unclear mechanism of action, and its rather long biological half-life in humans. This limit provides an ample margin of safety to prevent chloracne following repeated, acute exposure, and it addresses those chronic effects of TCDD observed in animal studies as well as those observed after accidental human exposure. The resulting body burden caused by chronic exposure to TCDD at the proposed OEL is examined. Its toxicological significance is compared with human tissue data and with other similarly persistent chemicals.(ABSTRACT TRUNCATED AT 250 WORDS)

Acne Vulgaris↗

By-side impurities in chloronaphthalene mixtures of the Halowax series: all 75 chlorodibenzo-p-dioxins.

A by-side chlorodibenzo-p-dioxins (CDDs) has been identified as impurity in concentration between 1.5 and 370 ng/g in the Halowax formulations of all type. Halowax 1014 was relatively richer in number of CDD congeners detected when compared to six other CN formulations examined. Amongst the mono- to tri-CDDs, the most prevalent in the Halowaxes were 1- and 2-MoCDD, and especially they were abundant in the formulations of a lower than a higher degree of chlorination. Amongst the tetra- to octaCDD only 1,2,3,4-/1,2,4,6-/1,2,4,9-/ 1,2,3,8-TeCDD, 1,2,3,4,6,7,8-HpCDD and OcCDD were found in all the Halowaxes, and 1,2,3,4,6,7,9-HpCDD remained undetected only in Halowax 1099 and 1013, while most of TeCDDs, PeCDD, and HxCDDs were absent in a majority of the formulations examined. The compositional profile of 1,2,3,4-/1,2,4,6-/1,2,4,9,-/1,2,3,8-TeCDD and OcCDD congeners found in the Halowaxes seem to indicate, that after an initial in situ formation of mono- and di-CDDs during CNs synthesis, a further increase of reaction time, temperature, and pressure can lead to successive chlorination of the already established chlorodibenzo-p-dioxin molecule, and so to enrichment in 1,2,3,4-/ 1,2,4,6-/1,2,4,9,-/1,2,3,8-TeCDD but also OcCDD content for most of the final products obtained. Nevertheless, also due to the co-synthesis of chlorophenols in the Halowaxes, their condensation reactions could also contribute to the formation of CDDs. In term of dioxin-like toxicity the most potent due to CDDs content was Halowax 1014 with 0.95 ng TCDD TEQ/g, and between 0.00068 and 0.058 ng/g were for other formulations. A rough estimation made implies that a net CDDs production due to manufacture of the technical CNs in the XX century could reach an amount between 3.0 and 12.6 kg, while for most toxic dioxin-like constituents between 5.25 and 24 g TCDD TEQ, For the worst case scenario and involvement of Halowax 1014 only the net total CDDs production was estimated to be 1.5 kg, and for highly-toxic congeners 71 g TCDD TEQ. All these figures are much lower when compared to co-production of CDFs.

Dioxins↗

Environmental transformation of triadimefon in water and on plant leaf surface.

Phototransformation of triadimefon was studied in aqueous solution and on plant leaf surface under natural and simulated conditions. Photoproducts such as 4-chlorophenol, 1-(4-chlorophenoxy)-3,3-dimethyl-1-(1,2,4-triazole-1-yl)-butan-2-ol and 1-phenoxy-3,3-dimethyl-but-2-one were identified on leaf as well as in aqueous solution. A new photoproduct product 1-(4-chlorophenoxymethyl)-1,2,4-triazole was identified only on the leaf surface. The rate of degradation was more in tap water as compared to rain and distilled water.

Chromatography, Gas↗

Nonionic polymeric micelles for oral gene delivery in vivo.

The main aim of this study was to investigate the feasibility of using nonionic polymeric micelles of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) as a carrier for oral DNA delivery in vivo. The size and appearance of DNA/PEO-PPO-PEO polymeric micelles were examined, respectively, by dynamic light scattering and atomic force microscopy, and their zeta potential was measured. Expression of the delivered lacZ gene in various tissues of nude mice was assessed qualitatively by 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside staining of sections and quantitatively by measuring enzyme activity in tissue extracts, using the substrate of beta-galactosidase, chlorophenol red-beta-D-galactopyranoside. In addition, the types of cells expressing the lacZ gene in the duodenum were identified by histological analysis. DNA/PEO-PPO-PEO polymeric micelles are a single population of rounded micelles with a mean diameter of 170 nm and a zeta potential of -4.3 mV. Duodenal penetration of DNA/PEO-PPO-PEO polymeric micelles was evaluated in vitro by calculating the apparent permeability coefficient. The results showed a dose-independent penetration rate of (5.75 +/- 0.37) x 10(-5) cm/sec at low DNA concentrations (0.026-0.26 microg/microl), but a decrease to (2.89 +/- 0.37) x 10(-5) cm/sec at a concentration of 1.3 microg/microl. Furthermore, when 10 mM RGD peptide or 10 mM EDTA was administered before and concurrent with the administration of DNA/PEO-PPO-PEO polymeric micelles, transport was inhibited ([0.95 +/- 0.57] x 10(-5) cm/sec) by blocking endocytosis or enhanced ([29.8 +/- 5.7] x 10(-5) cm/sec) by opening tight junctions, respectively. After oral administration of six doses at 8-hr intervals, the highest expression of transferred gene lacZ was seen 48 hr after administration of the first dose, with gene expression detected in the villi, crypts, and goblet cells of the duodenum and in the crypt cells of the stomach. Reporter gene activity was seen in the duodenum, stomach, and liver. Activity was also seen in the brain and testis when mice were administered 10 mM EDTA before and concurrent with DNA/PEO-PPO-PEO polymeric micelle administration. lacZ mRNA was detected in these five organs and in the blood by reverse transcription-polymerase chain reaction. Taken together, these results show efficient, stable gene transfer can be achieved in mice by oral delivery of PEO-PPO-PEO polymeric micelles.

Administration, Oral↗

Solid-phase microextraction in the analysis of food taints and off-flavors.

Selected food taints and off flavors, for which solid phase microextraction (SPME) has been used as a method for volatiles isolation, are the subject of review. Compounds responsible for musty and earthy odor off-flavors and taints in foods are discussed. This group contains haloanisoles, geosmin, and methylisoborneol. Chlorophenols are discussed as precursors of chloroanisoles and compounds impairing the flavor of food. Also described are volatile phenolic compounds responsible for medicinal off flavors, mainly ethyl phenols and vinyl phenols. Sulfur compounds that contribute to off-flavor are also discussed. Finally, a group of volatile compounds being the products of lipid oxidation are summarized. A short review of the formation, occurrence, and information on odor properties of all of these groups of compounds is given. Examples of SPME use for the analysis of compounds belonging to all described groups are shown. Elaboration of method parameters, fiber selection, experimental conditions, and quantitation of compounds are subjects of interest. Also, applications of SPME as a method for introduction of volatiles in mechanical olfaction technologies are shortly outlined.

Food Analysis↗

Exposure to polychlorinated dioxins and furans (PCDD/F) and mortality in a cohort of workers from a herbicide-producing plant in Hamburg, Federal Republic of Germany.

The relation between mortality (all cause; cancer; cardiovascular diseases (International Classification of Diseases, Ninth Revision (ICD-9), codes 390-459); ischemic heart diseases (ICD-9 codes 410-414)) and exposure to polychlorinated dibenzo-p-dioxins and -furans (PCDD/F) was investigated in a retrospective cohort study. The cohort consisted of 1,189 male workers in a chemical plant in Hamburg, Federal Republic of Germany, who had produced phenoxy herbicides, chlorophenols, and other herbicides and insecticides known to be contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin and other, higher chlorinated dioxins and furans. The authors reported previously on cancer mortality in this cohort for the follow-up period 1952-1989. The current study covers the years 1952-1992 and investigates the relation of PCDD/F exposure to mortality using a quantitative estimate of PCDD/F exposure for the whole cohort derived from blood and adipose tissue levels measured in a subgroup (n = 190). Quintiles and deciles of these estimates served as dose parameters in the estimation of relative risks (RRs), using year-of-birth stratified Cox regression. An unexposed cohort of gas workers served as an external reference group. The total mortality was elevated in all dose groups. The highest relative risk was observed for the highest 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) decile (RR = 2.43, 95% confidence interval (CI) 1.80 to 3.29). Cancer mortality and mortality due to ischemic heart diseases showed a dose-dependent relation with TCDD and all PCDD/F combined. The highest relative risks for cancer (RR = 3.30, 95% CI 2.05 to 5.31) and ischemic heart diseases (RR = 2.48, 95% CI 1.32 to 4.66) were observed in the highest PCDD/F exposure group. The pattern of effects and tests for trend were similar when the lowest exposure group within the chemical worker cohort served as the reference, but the relative risks were smaller and the confidence intervals were larger. Potential confounding exposures complicate the interpretation of the internal comparison. These findings indicate a strong dose-dependent relation between mortality due to cancer or ischemic heart diseases and exposure to polychlorinated dioxins and furans.

Causality↗

Development of a transgenic mouse model for carcinogenesis bioassays: evaluation of chemically induced skin tumors in Tg.AC mice.

Transgenic rodent models have emerged as potentially useful tools in the assessment of drug and chemical safety. The transgenic Tg.AC mouse carries an inducible v-Ha-ras oncogene that imparts the characteristic of genetically initiated skin to these animals. The induction of epidermal papillomas in the area of topically applied chemical agents, for duration of not more than 26 weeks, acts as a reporter phenotype that defines the activity of the test article. We describe here the activity of six chemicals that have been previously characterized for activity in the standard 2-year bioassay conducted by the National Toxicology Program (NTP). Homozygous female Tg.AC mice were treated with benzene (BZ), benzethonium chloride (BZTC), o-benzyl-p-chlorophenol (BCP), 2-chloroethanol (2-CE), lauric acid diethanolamine (LADA) and triethanolamine (TEA). BZ and LADA induced skin papillomas in a dose-dependent manner, while BCP induced papillomas only at the highest dose. BZTC, 2-CE, and TEA exhibited no activity. The correspondence of chemical activity in Tg.AC mice with that in the 2-year bioassay was high. A comparison of responsiveness to BZ and LADA was made between hemizygous and homozygous female Tg.AC mice. Both genotypes appear to be equally sensitive to maximum doses of active compounds. The results reported here indicate that the Tg.AC transgenic mouse model can discriminate between carcinogens and noncarcinogens and that both mutagenic and nonmutagenic chemicals can be detected. These studies provide support for the adjunctive use of the Tg.AC transgenic mouse skin tumor model in drug and chemical safety assessment and for the prediction of the carcinogenic potential of chemicals.

Animals↗

The estrogen receptor relative binding affinities of 188 natural and xenochemicals: structural diversity of ligands.

We have utilized a validated (standardized) estrogen receptor (ER) competitive-binding assay to determine the ER affinity for a large, structurally diverse group of chemicals. Uteri from ovariectomized Sprague-Dawley rats were the ER source for the competitive-binding assay. Initially, test chemicals were screened at high concentrations to determine whether a chemical competed with [3H]-estradiol for the ER. Test chemicals that exhibited affinity for the ER in the first tier were subsequently assayed using a wide range of concentrations to characterize the binding curve and to determine each chemical's IC50 and relative binding affinity (RBA) values. Overall, we assayed 188 chemicals, covering a 1 x 10(6)-fold range of RBAs from several different chemical or use categories, including steroidal estrogens, synthetic estrogens, antiestrogens, other miscellaneous steroids, alkylphenols, diphenyl derivatives, organochlorines, pesticides, alkylhydroxybenzoate preservatives (parabens), phthalates, benzophenone compounds, and a number of other miscellaneous chemicals. Of the 188 chemicals tested, 100 bound to the ER while 88 were non-binders. Included in the 100 chemicals that bound to the ER were 4-benzyloxyphenol, 2,4-dihydroxybenzophenone, and 2,2'-methylenebis(4-chlorophenol), compounds that have not been shown previously to bind the ER. It was also evident that certain structural features, such as an overall ring structure, were important for ER binding. The current study provides the most structurally diverse ER RBA data set with the widest range of RBA values published to date.

Animals↗

Role of gas chromatography-mass spectrometry with negative ion chemical ionization in clinical and forensic toxicology, doping control, and biomonitoring.

This paper reviews procedures for the detection or quantification of drugs, pesticides, pollutants, and/or their metabolites relevant to clinical and forensic toxicology, doping control, or biomonitoring using gas chromatography-mass spectrometry with negative ion chemical ionization (GC-MS-NICI). Papers written in English between 1995 and 2000 are reviewed. Procedures are included for the analysis of the following halogen-containing or derivatizable compounds in common biosamples, such as whole blood, plasma, or urine, and in alternative matrices such as sweat, hair, bone, or muscle samples of humans or rats: benzodiazepines, cannabinoids, opioids, acetylsalicylic acid, angiotensin-converting enzyme inhibitors, ketoprofen, methylphenidate enantiomers, tegafur, zacopride, anabolic steroids, chlorophenols, chlorpyrifos, hexachlorocyclohexanes, organochlorines, and polychlorinated biphenyls. The principal information on each procedure is summarized in three tables to facilitate the selection of a method suitable for a specific analytic problem.

Doping in Sports↗

Hodgkin's disease, work, and the environment. A review.

Hodgkin's disease (HD), a lymphoma with an annual incidence in the United States of approximately 7500 cases, primarily affects the lymph nodes, spleen, and liver. The point of this article is to critically review the literature regarding the purported relationships between HD, certain occupations, and exposure to chemical agents. Attention will also be focused on recent advances in molecular genetics in the etiology of this ailment. A MEDLINE search was conducted to assess case-control and mortality evaluations that investigated links between HD and certain occupations and exposure to designated hazards. A review of citations in the Silver Platter Occupational and Environmental Medicine CD-ROM database was also conducted to ensure that all pertinent reports were obtained. Of the industries evaluated, woodworking showed the most consistent link between an increased risk of HD (relative risk, 1.8 to 7.2), but not all studies conducted showed positive associations. Although certain chemicals (ie, chlorophenols, pesticides) were reported as risks, no chemical was consistently and unambiguously linked with HD. Recent investigative work, however, points to a major etiological role for the Epstein-Barr virus (EBV), genetic fragments of which have been noted in Reed-Sternberg cells, the classic malignant cells of HD. The occupation most consistently associated with HD appears to be woodworking, although no specific chemical has been consistently linked with this lymphoma. The most persuasive evidence regarding the cause of HD arises from recent studies, including epidemiological, clinical, and genetic studies, that point to a major role by the EBV.

Adolescent↗