bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative carcinogenic and mutagenic activity of coal tar and petroleum asphalt paints used in potable water supply systems
Authors: Robinson M. , Buii R. J. , Munch J. , Meier J. 
Published: October 2006

AbstractCoal tar and petroleum asphalt paints are among the products used as coatings for water pipes and storage tanks to retard corrosion. Formulations of these coatings were tested in the Ames mutagenesis and the mouse skin carcinogenesis bioassays. To test the mutagenicity of the paints, six doses ranging from 0.005 to 10 μl per plate were assayed. In the mouse skin bioassay, doses of the coal tar paints ranging from 0.2 to 200 μl were administered topically to 30 SENCAR mice per group. These initiating doses were followed by applications of 1.0 μg of 12‐o‐tetradecanoyl‐phorbol‐13‐acetate (TPA) in 0.2 ml acetone topically, three times weekly for 20 weeks. Petroleum asphalt paints were tested in groups of 40 animals at 200 and 600 μl doses. All coal tar paints showed mutagenic activity after metabolic activation with S‐9, with the highest response being in strains TA 98 and TA 100. None of the petroleum asphalt paints gave mutagenic responses. Both types of coatings resulted in positive responses in the initiation/promotion study. The coal tar paints gave rise to 1000–1800 times the tumor response observed with petroleum asphalt products. One coal tar product was positive when tested as a complete carcinogen in the mouse at 2 μl per application once weekly for 30 weeks, whereas the asphalt paint was negative at 100 times the dose. The biological responses to the products were greater than expected from their polycyclic aromatic hydrocarbon (PAH) content. These findings suggest that the hazard posed by these coatings may not be fully explained by their PAH contents.
Respiratory responses of humans exposed to an aerosol–gas pollutant mixture: Multivariate contrast of a complex atmosphere to clean air and sodium chloride aerosol controls
Authors: Kleinman M. T. , Bailey R. M. , Linn W. S. , Whynot J. D. , Anderson K. R. , Venet T. G. , Hackney J. D. 
Published: October 2006

AbstractData from a group of 20 subjects with normal baseline pulmonary function, who were exposed for 2 h to a test atmosphere containing a complex mixture of pollutants, have been contrasted with data from two other groups exposed to presumably non‐toxic control atmospheres. Group 1 was exposed to clean air, group 2 was exposed to clean air containing sodium chloride aerosol at 270 μg m−3, and group 3 was exposed to the complex atmosphere containing sodium chloride (332 μg m−3) and zinc ammonium sulfate (23 μg m−3) aerosols plus nitrogen dioxide (0.5 ppm) and sulfur dioxide (0.5 ppm). These atmospheres (ranked according to the presumed relative toxicities of the components; clean air=0, sodium chloride=1, complex mixture=2) were contrasted using multiple regression and partial correlation analyses. The effects of exposure to the complex gas‐aerosol mixture on forced expiratory performance were not significantly different from those observed in subjects exposed to clean air or to sodium chloride aerosol.
Blood glutathione as a measure of exposure to toxic compounds
Authors: Simplicio P. Di , Dolara P. , Lodovici M. 
Published: October 2006

AbstractBlood and liver glutathione levels were measured under the effect of an acute exposure to high doses of glutathione‐depleting substances. Among direct‐acting glutathione‐depleting substances, diethyl maleate (0.3, 0.7 and 1.4 ml kg−1) caused a marked reduction of both blood and liver glutathione, whereas methyl iodide (320 mg kg−1) led to a decrease in liver glutathione stores immediately and in blood stores with a longer latency. Indirectly glutathione‐depleting substances, like paracetamol (0.5–1.0 g kg−1) and styrene (250 mg kg−1), caused a reduction of liver glutathione, but not a similar reduction of blood glutathione. Blood glutathione is not a good measure of organ glutathione stores when dealing with indirect‐acting glutathione‐depleting substances.
Short‐term test systems to assess thiophosphoryl chloride standards
Authors: Coloşi‐Esca Doina , Anca Zoe , Barbarino Fedora , Surcel Didi , Papilian V. V. 
Published: October 2006

AbstractThe rat acute oral LD50 value of PSCI3 is 750 mg per kg body weight. A rat 90‐day oral feeding study at dose levels of 7.5 mg (P1) and 37.5 mg (P5) per kg resulted in increased body weight gain. Other responses inconsistently varied between dose levels. At 7.5 mg kg−1, a trend towards enhancement of relative weight of liver, spleen, kidney and adrenals was noted; at 37.5 mg kg−1, decreasing relative spleen and adrenal weights were observed. The most of the hematological and biochemical changes in blood serum cannot be believed to be transitory adaptive changes, but valid toxic effects. On the other hand, there are some indicators that suggest a possible trophic effect of this compound. However, the reversible dystrophic changes in liver, as well as the histochemical and histoenzymical results, require us to take into account that inactive chronic hepatitis could be reactivated by further toxic insult. A teratology study demonstrated increased number, body weight and length of fetuses, without apparent pathological events (tumors, external malformations). A mutagenicity test performed on rat femoral bone marrow after 30‐days feeding of 37.5 mg kg−1 did not indicate any significant change in the incidence of chromosomal aberrations, compared with the control group. The recommended maximum allowable concentration in the working zone for thiophosphoryl chloride in air was set at 3 mg m−3.
Gamma‐glutamyl transpeptidase: A sensitive marker in DDT and toxaphene exposure
Authors: García B. Martha , Mourelle Marisabel 
Published: October 2006

AbstractGamma‐glutamyl transpeptidase (GGTP) activity in rat liver plasma membrane and blood serum was investigated as an analytical marker for studying acute and sub‐chronic exposure to DDT and toxaphene. Twenty‐four hours after a single oral dose of DDT (200 mg per kg body weight) or toxaphene (110 mg per kg body weight), GGTP activity increased two‐fold in liver plasma membranes, followed by a return to normal values 48 h post‐exposure. In addition, serum GGTP activity doubled following acute exposure to DDT or toxaphene, and remained elevated for 48 and 96 h, respectively. Following 2 months continuous exposure to either insecticide, serum GGTP activity levels increased to double that of control values. GGTP activity in liver plasma membranes was elevated 2.5‐fold following the initial treatment with toxaphene (16.5 mg per kg body weight per day) and the activity remained high throughout the treatment period (120 days). Prolonged exposure with DDT (30 mg per kg body weight per day) did not produce any change in liver GGTP activity. Based on these results, it appears that GGTP activity could be used as a marker for acute DDT and toxaphene exposure.
Acute target organ toxicity of 1‐nitronaphthalene in the rat
Authors: Johnson Dale E. , Riley Michael G. I. , Cornish Herbert H. 
Published: October 2006

Abstract1‐Nitronaphthalene (1‐NN) produced respiratory distress and centrilobular liver necrosis in male Sprague‐Dawley rats after a single intraperitoneal injection (100 mg kg−1). Microscopic examination of the lungs of rats killed 24 h after the injection revealed a highly selective non‐ciliated bronchiolar (Clara) cell necrosis as the only remarkable lesion. Pretreatment of animals with phenobarbital offered complete protection from the respiratory distress induced by 1‐NN, but increased the severity of the hepatotoxicity. Pretreatment with SKF‐525A protected against 1‐NN‐induced liver necrosis, but did not alter the incidence or severity of the respiratory distress. Under similar conditions, this pattern of toxicity was not seen with the structural analogue 2‐nitronaphthalene.
Comparative effects of various lead salts on delayed hypersensitivity in mice
Authors: Descotes Jacques , Evreux Jean Claude , Laschi‐Locquerie Alda , Tachon Pierre 
Published: October 2006

AbstractIntraperitoneal administration of lead acetate, lead carbonate, lead chloride, lead nitrate or lead oxide at 0.5 or 6 mg per kg per day on five consecutive days was found to produce diverging effects on delayed hypersensitivity to sheep erythrocytes in Balb/c mice according to the salt used. Lead carbonate, lead nitrate and lead oxide exerted immunosuppressing properties, while lead acetate and lead chloride enhanced this cell‐mediated immune response. From these findings, it is concluded that lead immunotoxicity critically depends on which salt is present.
Dimethylnitrosamine genotoxicity in rat liver primary cell cultures with low cytochrome P‐450 levels
Authors: Mendoza‐Figueroa Tomäs 
Published: October 2006

AbstractLiver primary cell cultures (LPCC) with decreasing concentrations of cytochrome P‐450 were used to investigate the genotoxicity of the hepatic carcinogen dimethylnitrosamine (DMN) and the correlation between DMN genotoxicity and cytochrome P‐450 levels. Hepatocytes were isolated from partially hepatectomized rats and incubated with [3H]thymidine; single‐strand DNA molecular weight was determined by alkaline sucrose sedimentation. The molecular weight of DNA decreased 50% in LPCC plated either 2 or 24 h before being treated for 24 h with 70 μm DMN. Cytochrome P‐450 content was 188 pmol per mg protein in freshly isolated hepatocytes, whereas it was 70 and 32 pmol per mg protein in hepatocytes that had been cultured 24 and 48 h, respectively. Incorporation of 14C into acid‐insoluble material was the same in LPCC exposed 24 h to [14C]DMN starting either 2 or 24 h after cell plating. At non‐toxic concentrations (0.01‐1 μM), SKF 525‐A, an inhibitor of mixed‐function oxidase enzymes, inhibited approximately 20% of the binding of 14C from [14C]DMN to acid‐insoluble material in LPCC plated either 2 or 24 h before they were exposed to DMN for 24 h. Hepatocyte cultures exposed to the direct‐acting alkylating agent N‐methyl‐N‐nitro‐N‐nitrosoguanidine (at concentrations ranging between 6.8 × 10−8 and 6.8 × 10−5M) starting 2 and 24 h after plating, exhibited significant unscheduled DNA synthesis. These results indicate that DMN genotoxicity was similar in LPCC differing considerably in cytochrome P‐450 levels, and they suggest that DMN genotoxicity in these cultures is due mainly to similar DMN activation than to decreased DNA repair.
The effect of substrate and potassium on the inhibitory kinetics of mnci2 on the enzyme k+‐p‐nitrophenyl phosphatase in rat brain
Authors: Bansal S. K. , Husain Tahir , Murthy R. C. , Chandra S. V. 
Published: October 2006

AbstractThe effect of Mn2+, a divalent metal, on the enzyme K+‐p‐nitrophenyl phosphatase (K+‐PNPPase) was studied in rat brain. The metal was found to be a moderate inhibitor of the enzyme, with an I50 of approximately 480 μM. The inhibition was pH dependent, but not temperature dependent. On measurement of the inhibition with varying concentrations of PNPP (1–5 mM), the I50 value remained constant. However, when the inhibition was measured with K+ (5–20 mM), the lso value increased from 130 μM to 490 μM, suggesting that K+ antagonized the effect of Mn2+. In kinetic studies, Mn2+ inhibited the enzyme in a non‐competitive manner with respect to PNPP. The Km remained constant (2.9), but the Fmax was decreased from 5.0 to 1.6. However, with respect to K+, the inhibition was competitive, as the concentration for half maximal activation (K0.5) increased from 1.3 to 8.9 mmol I−1 with 1 mM of MnCl2, suggesting that the apparent affinity of K+ for the enzyme was decreased. The apparent Vmax was not affected. The degree of cooperativity (n) measured as the slope of the Hill plot remained unaltered (1.9 ± 0.2) over the entire concentration range of MnCl2 tested.
Application of dimethyl sulfoxide to skin of white and hairless mice
Authors: McGraw J. Leon , Greco John 
Published: October 2006

AbstractDimethyl sulfoxide (DMSO) was applied to a 2‐cm2 area on the backs of four groups of mice for a 5‐min period each day, 5 days per week, for the designated periods: groups I and II — six hairless albino mice (hrhr, c/c) per group — were treated for 8 weeks; group III — three hairless albino mice (hrhr, c/c) — were treated for 4 weeks; group IV — three white mice (ICR Swiss) — were treated for 8 weeks. A group of six untreated hairless albino mice (hrhr, c/c) (group V) functioned as controls for groups I, II and III, and a group of three white mice (ICR Swiss) (group VI) served as controls for group IV. Except for DMSO applications, controls were handled and treated in the same way as the experimental groups. At the end of the experimental periods, the claws of all appendages were removed, measured and average lengths were determined. The claws of group I and group II hairless albino mice were, on average, 2.4‐fold longer than the claws of the control hairless albino mice, a significant increase (p<0.01) in the average claw length. There was no significant difference in the lengths of the claws of the group III mice after 4 weeks of DMSO application. The claws of group IV (ICR Swiss mice) were, on average, 1.2‐fold longer than the claws of the control white mice, representing a significant increase (p <0.02) in claw length after 8 weeks of DMSO application.
Studies on the mechanism of toxicity of the mycotoxin sporidesmin. IV. Inhibition by copper‐chelating agents of the generation of superoxide radical by sporidesmin
Authors: Munday K. 
Published: October 2006

AbstractSporidesmin, the mycotoxin responsible for “facial eczema” in ruminants, has previously been shown to generate superoxide free radical, the latter being formed during autoxidation of the reduced form of the mycotoxin, a dithiol. The autoxidation of reduced sporidesmin is catalysed by iron and by copper, although cobalt, nickel, manganese, cerium, vanadium and molybdenum were found to be without effect. The catalytic activity of copper was some 900‐fold that of iron. Cyanide and certain organic complexing agents inhibit superoxide production from reduced sporidesmin by virtue of their ability to chelate copper. Some proteins behave likewise, again through binding of the metal catalyst, although arnino acid‐bound copper was found to be as effective as ionic copper in catalysing the autoxidation reaction. From the results of the present experiments, it is suggested that any superoxide production from sporidesmin in vivo would be mediated by the intracellular transport pool of copper. Furthermore, the ability of zinc to inhibit intestinal absorption of copper may be involved in the mechanism whereby salts of this metal afford protection against the harmful effects of sporidesmin in the living animal.
Renal handling of ‘filterable’ plasma metals and organic substances in man
Authors: Yokoyama Kazuhito , Araki Shunichi , Yamamoto Reiko 
Published: October 2006

AbstractTo estimate the plasma ‘filterable’ form concentration, glomerular filtration and tubular reabsorption in man for metals and organic substances, the regressions of the 24‐h urinary excretion of lead (Pb), inorganic mercury (Hg), δ‐aminolevulinic acid (ALA) and coproporphyrinogen (CP‐gen) on glomerular filtration rate were examined. The regressions were significant for ALA in two ‘healthy’ men examined and for Pb and for CP‐gen in one of them. From these data, it was estimated that the plasma concentration of ‘filterable’Pb was approximately 0.01 μg dl−1; the ALA concentration was 2.3 and 4.5 μg dl−1; and CP‐gen was 0.11 μg dl−1. Similarly, the filtered loads of Pb, ALA and CP‐gen were assumed to be nearly twice as large as their urinary excretion. Hg was not considered to undergo glomerular filtration.
Teratologic evaluation of alcide® liquid in rats and mice. I
Authors: Skowronski Gloria A. , Abdel‐Rahman Mohamed S. , Gerges Samy E. , Klein Kenneth M. 
Published: October 2006

AbstractAlcide®, a liquid sterilizer, was evaluated for teratogenic potential in rats and mice. Sodium chlorite and lactic acid, the active ingredients of this compound, form chlorine dioxide when mixed. Pregnant rats and mice were administered 1 ml and 0.1 ml, respectively, of Alcide® liquid by gavage on days 6–15 of gestation. The general health of the dams was evaluated and the fetuses examined for external, visceral and skeletal malformations. There was no evidence of maternal toxicity among treated rats and mice. Fetal viability, weight, length and number of resorptions were comparable with control groups. Teratogenic toxicity was not detected in either species. There was some incidence of skeletal and visceral anomalies; however, these variances were not significantly different from control animals.
Respiration of F344 rats in nose‐only inhalation exposure tubes
Authors: Mauderly Joe L. 
Published: October 2006

AbstractThe respiration of naive F344 rats confined in nose‐only inhalation exposure tubes was measured to obtain data for normal adult rats of different ages and to evaluate the tubes for exposures lasting several hours. Exposure tubes were modified for use as volume‐displacement plethysmographs. Respiration of 10 male and 10 female rats at 3, 6, 12 and 24 months of age was measured in the tubes during simulated exposures of up to 6 h duration. Measurements included respiratory frequency, tidal volume, minute volume and body surface temperature. The mean respiratory frequencies of 3, 6, 12 and 24 month old rats during the first hour of exposure were 172, 152, 123 and 136 breaths min−1, respectively. Minute volumes were 1.40, 089, 0.67 and 0.82 ml g−1 body weight, respectively. Both frequency and minute volume g−1 body weight were significantly greater for the youngest group, declined with age to 12 months and then increased at 24 months. Minute volumes g−1 body weight were similar for males and females. Minute volume and respiratory frequency of 3 and 12 month old rats declined progressively between 1 and 6 h of confinement in the tubes. Surface temperature did not increase after the first hour. The age and sex‐specific data provide a basis for predicting respiration of naive tube‐confined rats during inhalation exposures to non‐irritating materials.
Intestinal absorption of aluminum in rats: Effect of intraluminal pH and aluminum concentration
Authors: van der Voet Gijsbert B. , de Wolff Frederik A. 
Published: October 2006

AbstractThe intestinal absorption of aluminum (Al) was studied in an in situ perfusion system of rat small intestine in combination with systemic and portal blood sampling. The jejunum‐ileum was perfused with media containing 4.63, 9.25 and 18.50 mmol l−1 Al chloride at pH 4.0 and 7.0. Both mucosal retention and release of Al into the blood increased at increasing perfusate concentrations. Mucosal retention was not affected by pH but at lower pH more Al was released into the blood. The amount of Al which appeared in the blood was linearly related to the mucosal retention. The Al release into the blood was much less (μmol l−1) than the mucosal retention (mmol l−1). It is concluded that the intestinal absorption of Al is pH‐ and concentration‐dependent.
The role of the red blood cell in the transport of carbon disulfide
Authors: Lam Chiu‐Wing , Distefano Victor , Morken Donald A. 
Published: October 2006

AbstractWhen rats were exposed to 2 mg l−1 (˜640 ppm) of carbon dislfide (CS2) for 4 h, the concentration of free CS2 in the red blood cells (RBCs) approached a plateau within 2 h. Free CS2 in plasma reached a steady state concentration within 15 min of exposure. More than 90% of the free CS2 in blood was found in the RBCs regardless of the length of exposure. In vitro studies showed that about 90% of the free CS2 partitioned into the RBCs regardless of whether the CS2 was added first to the plasma or directly to the RBCs. Hence, it appears that the RBC is the major carrier of CS2 in blood. It was found that 98% of the free CS2 in red blood cell lysates was associated with hemoglobin. Free CS2 in RBCs was readily partitioned into olive oil (RBCs/oil=1/6), less readily into the plasma (RBCs/plsma=12/1), and only to a small extent into phosphate buffer (RBCs/buffer=39/1). The extraction of free CS2‐loaded RBCs into albumin solution increased with increasing albumin concentrations. CS2 can be extracted with buffer, protein solution, and oil, indicating that CS2 in RBCs can be transferred to the medium in which the RBCs contact. It is proposed that RBCs may also play an important role in the transport of CS2 from lung to tissues and vice versa. The possible role of RBCs in the transport of other organic solvents in the blood is also discussed.
Detection of andromedotoxins for the diagnosis of rhododendron poisoning in animals
Authors: Humphreys D. J. , Stodulski J. B. J. 
Published: October 2006

AbstractA method for the detection of andromedotoxin in plant material and relicta from cases of poisoning due to Rhododendron and other members of the Ericacea is described. This method, which overcomes the problems associated with basing the diagnosis on the clinical signs exhibited and untrained identification of plant materials, has been successfully applied to the investigation of a number of field outbreaks of Rhododendron poisoning in animals.
Penetration of nicotine and nitrosonornicotine across porcine oral mucosa
Authors: Squier C. A. 
Published: October 2006

AbstractThe use of smokeless tobacco (chewing tobacco or snuff) results in contact between this material and the lining of the mouth over relatively long periods of time. As tobacco contains nicotine and a carcinogen, nitrosonornicotine (NNN) there is a likelihood of systemic absorption of both these compounds under these conditions. This study measured the penetration of nicotine and NNN across skin and various regions of oral mucosa. Specimens of porcine skin, keratinized gingiva and non‐keratinized floor of mouth and cheek mucosa were placed in perfusion chambers and the flux across these tissues of isotopically labeled water, nicotine and NNN was determined; permeability constants were calculated for each compound and for each region and the values compared statistically. Skin showed a lower permeability than the oral regions to all compounds and floor of mouth was generally the most permeable site. Nicotine passed across oral mucosa almost as rapidly as water, the most permeable region being floor of mouth, whereas gingiva and buccal mucosa showed a similar, but lower, permeability. The non‐keratinized oral carcinomas, regions with the higher permeability being sites that show the greatest tendency to develop such lesions.