[Amoebic liver abscess--case report].

Authors describe a case of asymptomatic amoebic liver abscess discovered at the seven years old boy admitted, and operated on account of appendicitis. In otherwise correct postappendectomy period raised leucocytosis and ESR was observed. Ultrasound examination revealed an abscess in the right liver lobe.

Effects of occupational exposure to a mixture of solvents on the inner ear: a field study.

Some clinical and laboratory studies indicate that industrial solvents such as toluene, styrene, xylene, trichloroethylene and carbon disulfide or their mixtures may affect the inner ear, although the mechanism of this process is still not well understood. The aim of this investigation was to assess the incidence of hearing and vestibular disorders (using modem audiological and vestibular tests) in 61 workers exposed to a mixture of organic solvents at the production of paints and varnishes; the control group included 40 age-matched non-exposed subjects. Environmental and biological monitoring revealed that the most significant exposure can be attributed to the following mixture constituents: ethylbenzene, xylene and trimethylbenzene isomers such as pseudocumene, mesitylene and hemimellitene.

[New sources of occupational exposure in modified or new technological processes].

Mixtures of organic solvents with frequently changing composition are employed in many industries. It is true that dangerous solvents are eliminated from the work environment, but simultaneously new manufacturing techniques are implemented. Glues, varnishes and stains, containing chemicals of unknown toxicity and non-recognized effects on the human body are extensively used in the footwear and furniture industries.

[Specific nature of the software used to construct simulations: physiologically-based toxicokinetic models].

Building of the physiologically-based toxicokinetic (PBTK) models is based on the application of simulation languages, such as advanced continuous simulation language (ACSL). The aim of this study was to develop the principles of constructing the fundamental model and the models dedicated to chemicals found in the work environment (e.g.

[Use of the ACSL simulation language for physiologic toxicokinetic models].

For the description of the processes of absorption, excretion or elimination of chemicals, the open one- or two-compartment models have been used thus far. The latter consist mainly of the fast (central) and slow (peripheral) compartments. The toxicological studies were based on an assumption that the organic processes develop according to is the first order kinetic reaction.

[Compartment simulation models and physiologic use in pharmaco- and toxicokinetics].

The pharmaco- and toxicokinetic studies describe the process of absorption, distribution, metabolism and elimination of drugs or chemical compounds in animals and humans. In simple compartmental models, the body is divided into basic compartments, central and peripheral. The central compartment is an equilibrium of arterial and venous blood flows, and the peripheral one is connected to the central compartment through a series of flow rate constants that describe the flow of chemicals in both directions.

Biological monitoring of experimental human exposure to trimethylbenzene.

Trimethylbenzene (TMB) is a component of numerous commercial preparations of organic solvents (Farbasol, Solvesso, Shellsol) used in the chemical, plastics, printing and other industries. TMB is a mixture of three isomers (pseudocumene-1,2,4-TMB; mesitylene-1,3,5-TMB; hemimellitene-1,2,3-TMB). The proportion of individual isomers in the mixture differs.

[Comparison of standard methods for determination of pseudocumene in urine using gas chromatography with the headspace technique and a new method using a headspace automatic sampler].

The biological indicators that have been proposed for monitoring occupational exposure are: concentration of the solvent or metabolized compounds in alveolar or expired air samples, in venous or arterial capillary blood samples and in urine samples. Recently, many researches have reported significant relationships between the time-weighted average exposure and the urinary concentrations for various solvents. The aim of our study was to compare two methods in which urinary concentrations of pseudocumene were determined by gas chromatography using headspace technique.

[Use of biological monitoring for evaluating occupational exposure in the paint and varnish industry].

Multi-component solvent mixtures are used in the painting and varnishing industry. Trimethylbenzene (TMB approximately 50%) is a main component of these mixtures. Assessment of occupational exxposureto TMB and xylene based on the biological exposure index (capillary blood, urine) was the aim of the study.

[Alkyl derivatives of benzene, indene, naphthalene, diphenyl and fluorene as a potential source of occupational and environmental exposure].

Mixtures of organic solvents are used extensively in industry. The aim of this study was to develop a method for the determination of components of commercial multi-component solvent mixtures, and to perform qualitative and quantitative analyses of the mixtures. Farbasol, Solvesso and Shellsol mixtures were analysed by gas chromatography with a mass spectrometry detector (GC/MS).

[Determination of dimethylbenzoic acid isomers in urine by gas chromatography].

Trimethylobenzene (TMB) is a main ingredient of many organic solvents used in industry. In Farbasol (Polish trade name of the solvent) TMB occurs as a mixture of three isomers: pseudocumene (1, 2, 4-TMB) 30%; mesitylene (1, 3, 5-TMB) 15%; hemimellitene (1,2,3-TMB) 5%. As it is known in human organism, TMB is metabolized mainly to dimethylbenzoic (DMBA) and dimethylhippuric (DMHA) acids, and some authors suggest, that the acids excreted in urine can be biological indicators of exposure to TMB.

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.

[Micromethods for determining organic solvents in blood by headspace analysis].

The evaluation in industrial exposure to volatile organic compounds based on assessing concentrations of unchanged substances in blood of exposed workers seems to gain increasing interest. The main obstacle to a wide application of this method is the difficulty in collecting venous blood samples. Many authors suggest determining volatiles in capillary blood samples because they display the same concentrations as the arterial blood samples.

Metabolic disposal of antipyrine and lipid peroxidation indices in volunteers jointly exposed to industrial organic solvents and ethanol.

Each of twelve volunteers, at 2 week intervals, received 1 g of antipyrine, a test drug, and were exposed for 4 h either to toluene (375 mg/m3) or xylene (435 mg/m3) singly or in combination with ethanol (0.45 g/kg body wt. before the onset of exposure and 0.

Toluene determination in capillary blood as a biological indicator of exposure to low levels of toluene.

The possibility of evaluating occupational exposure to toluene at low levels (50-150 mg/m3), based on the determination of unchanged substances in capillary blood, was investigated. The volunteers were exposed in a toxicological chamber; during and after exposure venous and capillary blood samples were analysed by gas chromatography using the headspace technique. Toxicokinetic data point out that determination of toluene should be performed in blood samples collected 15-20 min after termination of exposure.

Neurobehavioral effects of experimental exposure to toluene, xylene and their mixture.

The effects of experimental exposure to toluene (100 ppm), xylene (100 ppm) and their mixture (50 ppm of toluene and 50 ppm of xylene) on CNS functions were studied in 10 male volunteers aged 22-35. Changes in CNS functions were measured by means of nine psychological tests. Acute exposure to xylene produced the most adverse effect on simple reaction time SRT and choice reaction time ChRT.

Excretion of methylbenzoic acid in urine as a result of single and combined exposure to m-xylene.

Influence of combined exposure to solvent vapours on the metabolism of m-xylene and the kinetics of excretion of methylbenzoic acid (MBA) in urine was investigated. The volunteers were exposed in groups of four or five. Each experiment consisted of two parts.

[Determining trichloroacetic acid in the urine by the gas chromatography method].

It has been found that the method of determination of trichloroacetic acid in urine after Monster and Boersma due to high detectability and specificity may be used for determination of trichloroacetic acid (TCA) in urine particularly when aimed at evaluation of exposure to tetrachloroethylene (PERC) or to trichloroethylene (TRI) et low concentrations range. The improvement of determinations precision has been obtained by introduction of internal standard. In case of application of full procedure for trichloroacetic acid solutions in urine ranging from 1.