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PubMed1976

ECG changes in benzene, toluene and xylene poisoned rats.

Electrical activity of the heart was studied in acute, subacute and chronic benzene, toluene and xylene poisoning by means of NEK-2 type apparatus in CFY male rats. In the early period of acute intoxication benzene and its methyl derivatives, injected either intraperitoneally or subcutaneously or administered by inhalation did not cause changes in the ECG. Intravenously injected toluene induced a rapid and permanent decrease in blood pressure, in higher doses respiratory paralysis. In acute inhalation toluene and xylene poisoning the anesthesia was followed by respiratory paralysis, bradyarrhythmia and asystole, while inhalation of benzene induced respiratory paralysis followed by ventricular fibrillation. Subacute poisoning with benzene, toluene and xylene caused disorders in repolarization and arrhythmia. The degree, incidence and development of these phenomena depended on the dose and the duration of exposure. The effect of benzene influencing ECG was appreciably more intensive than that of toluene or xylene. Owing to the high number of spontaneous ECG changes due to ageing, it is difficult to evaluate the effect of chronic exposure to the agents under investigation.

Acute Disease↗

PubMed1978

[Control of occupational exposure to benzene in a chemical plant].

Later on detection of several cases of acute myelotoxic intoxications the use of benzene as a solvent has been banned in Italy since 1963 (Law n. 245). Its consumption has therefore been confined to synthesys processes in petrolchemical industry. The hazards arising from the operations performed in an open air chemical plant which produces alkylbenzene were monitored by the AA. The synthesis occurs in a closed system which provides opportunities for benzene exposure during filling, control and maintenance operations. Nine environmental samples out of 10 showed benzene concentrations above 10 ppm with peaks up to 110 ppm. Long term air sampling showed values ranging from 12 to 75 ppm. Urinary phenol elimination has been measured showing values above 50 mg/1 for approximately 20% of workmen. The difficulties pertaining to an adequate control of benzene exposure in chemical plants are discussed. Being skin contact a mode of entry of apreciable concern, the AA. stress out that priority in exposure monitoring should be given to biological tests such as urinary phenol level and benzene concentration in expired air measurements.

Air Pollutants↗

PubMed1977

Leukaemia in benzene workers.

Workers occupationally exposed to benzene in 1940-49 were followed for vital status up to 1975. In comparison with two control populations, a significant (P less than 0-002) excess of leukaemia was observed. A five-old excessive risk of all leukaemias and a ten-fold excess of deaths from myeloid and monocytic leukaemias combined are demonstrated in the study population compared with controls. These figures under-estimate the true leukaemia risk to benzene-exposed workers, because follow-up is only 75% complete and the untraced 25% of the study population were all regarded, in the statistical analysis, as being alive at the end of the study period. The environment of the workers in the study population was not contaminated with solvents other than benzene, and existing records indicate that the benzene levels themselves were generally below the limits recommended at the time of their measurement.

Adult↗

PubMed1975

Purification and some properties of a soluble benzene-oxidizing system from a strain of Pseudomonas.

1. A soluble enzyme system which oxidizes benzene to cis-1,2-dihydroxycyclohexa-3,5-diene (cis-benzene glycol) was obtained from a species of Pseudomonas grown on benzene as the major carbon source. 2. The system was shown to consist of three protein components. Two of these were non-haem-iron proteins of molecular weight approx. 21,000 and approx. 186,000 and the other was a flavoprotein of molecular weight approx. 60,000. 3. Fe2+ and NADH were essential cofactors for benzene oxidation.

Bacterial Proteins↗

PubMed1977

[Activity of beta-glucuronidase in peripheral blood leukocytes in rats subjected to subacute benzene vapor poisoning].

The work presents the results of investigations on the activity of beta-glucoronidase (B-GR) in neutrophiles and lymphocytes of peripheral blood in rats of Wistar strain exposed to benzene vapours of the concentration 27000 mg/m3, 6 hrs daily for 10 consecutive days. The activity of the enzyme in both types of cells was determined by cytochemical method; Hayashi et al. After an exposure to benzene, a statistically significant reduction of the number of granulocytes and lymphocytes was found. The activity of B-GR in granulocytes was lowered 5--times compared with the initial value (before exposure). The per cent of B-GR--positive lymphocytes was not changed. Instead, apparent changes in proportional values of individual types of enzyme--positive cells were found. The per cent of granular lymphocytes decreased, and at the same time the per cent of granular--diffusive and diffusive lymphocytes increased. The authors think that benzene affects granulocytes cells depressively and that it is an active labilisator of lysosomal lymphocytes. They set their hopes on the observed phenomenon to elaborate an exposure test to benzene.

Animals↗

PubMed1977

[Effect of selenium on peripheral blood in rats chronically exposed to benzene].

The studies have been performed on 32 adult male rats of Wistar strain, divided into three groups. Control rats have been exposed to benzene vapours, of 1200 mg/m3 concentration, 6 hours daily, for 12 weeks. In the remaining two groups, before the exposure to benzene vapours, the rats had been given, to their stomachs, sodium selenate at the dose of 1.0 and 5.0 microgram/kg (converting to selenium), for 10 consecutive days. In the blood from a tail, before the experiment and after 6 and 12 weeks of exposure to benzene, some hematological indices were determined. In control group and in rats which before the exposure had been administered selenium at the dose of 1.0 microgram/kg, lymphocytopenia, correlating with duration of exposure, and thrombocytopenia were found. In rats which before the exposure had been given selenium at the dose of 5.0 microgram/kg, lymphocytopenia did not occur and thrombocytopenia occurred as late as after 12 months of exposure. The authors think that selenium at the dose of 5.0 microgram/kg, indicates a protective effect on lymphocytic system, before benzene's toxic effects.

Animals↗

PubMed1978

[Changes in lysosomal activity of beta-glucuronidase in leukocytes of rats exposed to benzene under selenic protection].

The authors demonstrated that a chronic exposure to benzene caused in rats a reduction in the number of lymphocytes in peripheral blood, decrease in beta-glucoronidase (BG) activity in neutrophils and increase in BG-positive lymphocytes fraction. In addition, a failure was found in lysosomes of lymphocytes, revealed by scattering of a given enzyme in cytoplasma. Administration of 1.0 microgram/kg for 10 consecutive days before benzene exposure, did not prevent lymphocytopenia but hampered BG activity decrease in neutrophils as well as a damage to lymphocytic lysosomes. Administration of 5.0 microgram/kg for 10 successive days prior to benzene exposure, prevented lymphocytopenia and caused a reactive increase in the amount of neutrophils and resulted in an increase of BG-positive lymphocytes fraction, especially those with cytoplasmatic localization of enzyme. The results obtained demonstrate that only a smaller dose of selenium protected lysosomal membrane of lymphocytes from toxic effects of benzene, whereas both selenium doses protect BG in neutrophils.

Animals↗

PubMed1978

Hematologic and hemopoietic alterations following experimental benzene exposure in newts (Triturus cristatus).

Changes in the hematological picture in newts have been investigated utilizing benzene exposure. The first deviation occurs in circulating white cells that become more numerous. Subsequently there is an increase of immature cells on the cortical zone of the liver. About two weeks after the first treatments a decrease of circulating leukocytes begins and the immature white cells continue to increase both in circulation and in the cortical zone of the liver. The red cells present a decrease after one month of treatment. This is preceeded by a decrease in hemoglobin percentage and an increase in the size of red cells and in the number of immature red cells. The data concerning animals treated with an hemolytic agent and with benzene demonstrates an early action of benzene also on red cells. The results suggest a maturation in capacity caused by benzene in both white and in red cells. The intensity of alteration seems proportional to the frequency of treatments. The onset of a particular modification, however, is related to the time interval following the first treatment.

Animals↗

PubMed1979

Transcutaneous gamma benzene hexachloride absorption and toxicity in infants and children.

A premature, malnourished infant had seizures and abnormal neurological function associated with topical gamma benzene hexachloride (lindane) therapy. The level of gamma benzene hexachloride in his blood was 17 times greater than expected after a single topical application of 1% gamma benzene hexachloride. Significant levels developed in another child's blood after repeated applications of small amounts to areas of dermatitis and excoriations on the skin. The use of topical gamma benzene hexachloride in pediatric patients is reviewed because of increased evidence of unpredictable absorption and toxicity.

Administration, Topical↗

PubMed1978

Mutagenicity in Salmonella typhimurium mutants of the benzene-soluble organic matter derived from air-borne particulate matter and its five fractions.

Air-borne particulate matter was collected on a filter, then extracted with benzene. The benzene-soluble material was separated into 5 fractions, namely acidic, basic, alipathic, polyaromatic and oxygenated fractions. The mutagenic activities of these fractions were examined with a set of Salmonella typhimurium mutants. The 6 mutants were from the TA1535 series, deep rough strains without excision repair, namely TA100 and TA98 (having a resistance-transfer factor) and the standard strain TA1535, TA1536, TA1537 and TA1538. Linear dose-response curves were obtained for the benzene-soluble organic matter, and its acidic, polyaromatic and oxygenated fractions with strain TA98 and a 9000 X g liver supernatant from both phenobarbital(PB)- and dibenz(a,h)anthracene(DBA)-treated rats. Among the 5 fractions tested, 3 fractions, namely the acidic, polyaromatic and oxygenated, played an important role in the mutagenicity of the benzene-soluble organic matter derived from air-borne particulate matter. The 9000 X g rat-liver supernatant was not required to make the acidic fraction mutagenic.

Air Pollutants↗

PubMed1977

Chlorinated benzenes in the environment.

Chlorinated benzenes are composed of twelve chemical species: one mono-, three di-, three tri-, three tetra-, one penta-, and one hexachlorobenzene. Most of these are not only important intermediates for various kinds of chemicals but are also extensively employed for various applications singly or in combination. For example, 1,4-dichlorobenzene is used chiefly against termites in soil; trichlorobenzenes are used as solvents for pesticides and also as heat transfer agents with PCBs; the mixture of trichlorobenzene and tetrachlorobenzene is applied in controlling shellfish predators; and hexachlorobenzene is applied to wheat as a fungicide in some countries and as an additive to rubber products. The annual production (1973) of monochlorobenzene, 1,2-dichlorobenzene, and 1,4-dichlorobenzene in Japan was about 23,000, 9000, and 20,000, tons, respectively. Production volumes of other chlorinated benzenes are not well known but are assumed to be smaller than those of the above three compounds. The total annual production of chlorinated benzenes far surpasses the peak production of PCBs (7000 tons/year) which are known as a ubiquitous pollutant in this country. Since chlorinated benzenes have a chemical structure and properties similar to those of PCBs and PCTs, it seemed necessary to direct our attention to environmental contamination by these materials. The present paper describes only the occurrence and the fate of these materials. Toxicity and biological impact are not referred to here.

Air Pollution↗

PubMedDate not supplied

Mortality among individuals occupationally exposed to benzene.

The mortality experience of 594 individuals occupationally exposed to benzene was investigated using a retrospective cohort design. Three hundred thirty-five of the employees began working in benzene areas prior to 1950, which provided a sound data base from which to examine latency. Data derived from work histories and industrial hygiene records permitted estimation of exposure intensities and cumulative dosages for each employee. No mortalities directly attributable to benzene exposure were observed. Several cases of leukemia and other blood disorders were noted and discussed.

Anemia↗

PubMed1979

Distribution of Fe59 in benzene and iomex treated rats.

The distribution of Fe59 in plasma and blood at various time intervals has been studied in control, benzene and iomex administered, and anemic rats. A significant difference between control and benzene, and iomex treated animals was observed in the rate of reappearance of Fe59 in blood circulation. The accumulation of Fe59 in various organs was noted at the end of 48 h. A significant increase in the radio-iron content was observed in bone marrow, spleen and liver of benzene and iomex treated rats as compared to those of control rats.

Alkenes↗

PubMed1979

Petit mal and grand mal seizures produced by toluene or benzene intoxication in the cat.

Motor incoordination, euphoria and hallucinations are symptoms reported for humans voluntarily intoxicated by industrial solvents. An epileptic-like consciousness impairment has also been noted. The present paper describes a technique used for the experimental study of solvent intoxication in which toluene and benzene can be applied directly into the trachea of freely moving cats with chronically implanted electrodes. This technique permits the control of solvent dose and time of exposure. Results showed a 3 Hz spike-wave activity in the gyrus cinguli recording with both toluene or benzene intoxication. Furthermore, benzene inhalation produced generalized tonic-clonic seizures. These effects were dose-related. However, a sensitization period was essential for the development of such alterations, and effects showed a tendency to shortening through chronic exposures. These alterations were correlated with behavioral disturbances such as nodding, twitching and apparent hallucinations. Results are discussed regarding the sensitization period, the optimal peak of effects, and the period of tolerance development relevant to an earlier found amygdalar activation that could be correlated with other methods inducing experimental seizures, such as repetitive stimulation of the brain (kindling).

Amygdala↗

PubMed1975

The dynamics of histoenzymatic changes in the kidney in acute poisoning with benzene.

The experiments were carried out in mice which were divided into 4 experimental groups and a control group. In the course of the experiment SD, NADH2-tetrazolium reductase; ATP-ase, G-6-P-ase and AP were observed. It was found that acute benzene intoxication causes the disturbances in the enzymatic activities of the cells of the main segment of the nephron. The impairment of tissue respiration and oxygen phosphorylation and of active transport is due to benzene intoxication. Benzene leads to injury of the endoplasmatic reticulum in the cells of the kidney.

Acid Phosphatase↗

PubMed1978

The behaviour of some enzymes in the mouse liver due to chronic benzene intoxication.

1. Long trem benzene action brings about a permanent decrease in oxidoreductive enzymes and active transport as well as an inactivation of the lysosomal apparatus in liver-cells. 2. Particular liver lobule zones show different sensitivity to toxic action of benzene which might result from their different role in the processes of benzene biotransformation.

Acid Phosphatase↗

PubMed1977

A study of benzene exposure versus urinary phenol levels.

On the job benzene vapor exposures of less than 5 ppm were measured concurrent with the 24 hour collection of urine from 52 employees. Urinary phenol levels of the collective study group, measured as either concentration or weight, showed a positive statistically significant correlation with benzene exposure. However, due to variances in individual baseline phenaol levels, determination of benzene exposure at these low concentrations is relatively weak. Since baseline phenol concentrations exist over a range of values, adjustment for a single value of each individual's baseline did not improve correlation for the collective study group.

Air Pollutants, Occupational↗

PubMed1979

Embryotoxicity of inhaled benzene in mice and rabbits.

The effect of inhaled benzene on embryonal and fetal development was assessed in mice and rabbits. CF-1 mice and New Zealand white rabbits were exposed to 0 or 500 ppm of benzene for 7 hr per day from days 6 through 15 (mice) and 6 through 18 (rabbits) of gestation. Little evidence of maternal toxicity was seen in either species. Although some signs of embryonal toxicity were observed in both mice and rabbits, a teratogenic effect was not discerned in either species inhaling 500 ppm of benzene.

Aerosols↗