bluuebunny/crossref_metadata_2025_split huggingface dataset:
Subjective symptoms in workers with low‐level exposure to lead
Authors: Fischbein Alf , Thornton John C. , Sarkozi Laszlo , Kon Steven , Levin Stephen 
Published: October 2006

AbstractIn an attempt to identify health effects associated with low‐level lead exposure, 45 cable‐manufacturing workers underwent clinical examinations in a cross‐sectional study. Thirteen workers were in direct contact with lead‐containing stabilizers, while 31 were only indirectly exposed. The directly exposed had a higher prevalence of reported neurological and gastrointestinal symptoms than those with low or insignificant lead exposure. None of the directly exposed had blood lead levels exceeding 60 μg per 100 ml. The clinical symptoms correlated with blood lead and zinc protoporphyrin. However, when the data were subjected to hierarchical log–linear modeling, a partial association was found between zinc protoporphyrin and symptoms, but not between blood lead and symptoms. The data suggest that non‐specific neurological and gastrointestinal symptoms may occur at relatively low blood lead and zinc protoporphyrin levels, and that measurement of zinc protoporphyrin and exploration of clinical symptoms are valuable components in lead screening programs.
Toxic alkaloids and their interaction with microsomal cytochrome P‐450 in vitro
Authors: Peeples A. , Dalvi R. R. 
Published: October 2006

AbstractStudies on the binding spectra of certain alkaloids with rat liver microsomes revealed that brucine, scopolamine and strychnine are type I compounds, whereas boldine, emetine, nicotine, reserpine and sanguinarine show type II binding. In contrast, colchicine and solanine failed to produce any measurable binding spectra. In vitro incubation of colchicine, nicotine or scopolamine with microsomal suspensions and NADPH resulted in demethylation of these alkaloids, while the incubation of boldine, brucine, emetine, reserpine, sanguinarine or solanine showed little or no dealkylation reaction. Furthermore, the effect of these alkaloids on the in vitro microsomal metabolism of a drug, benzphetamine, has also been studied.
Blood levels of caffeine and results of fetal examination after oral administration of caffeine to pregnant rats
Authors: Ikeda George J. , Sapienza Philip P. , McGinnis Marcy L. , Bragg Lois E. , Walsh John J. , Collins Thomas F. X. 
Published: October 2006

AbstractPregnant FDA‐strain Osborne–Mendel rats were administered repeated doses of caffeine by oral intubation (gavage) and by administration in the drinking water (ad libitum sipping). When [1‐methyl‐14C] caffeine was administered at a dosage of 80 mg per kg per day by ad libitum sipping on days 12 to 15 of gestation, the amounts of radioactivity in blood were variable; the highest level on day 12 was 0.2% of the dose per ml of blood. The highest blood level of caffeine observed during a 24‐h sampling period averaged 5.7 μg ml−1. When [14C] caffeine was administered by gavage at a dosage of 80 mg kg−1 on day 12, the blood level of radioactivity reached a peak of 0.4% of the dose per ml of blood and declined rapidly thereafter. The highest amount of caffeine observed in blood averaged 63.1 μg ml−1, 1 h after gavage. The overall blood elimination half‐life of radioactivity in pregnant rats treated by gavage was 2.6 h, and the half‐life of caffeine in blood was 1.7 h. The levels of radioactivity in the fetus and maternal muscle per unit weight were comparable after each method of administration. A comparison of autopsy results from both groups indicated that resorptions were increased when compared with rats that did not receive caffeine; this effect was more marked in the gavage group than in the ad libitum sipping group. Ectrodactyly was observed only in offspring of the gavage group. The incidences of ectrodactyly or resorptions did not appear to be directly related to nutrition or fluid intake.
Urinary mercapturic acid in chemical workers and in control subjects
Authors: Buffoni F. , Santoni G. , Albanese V. , Dolara P. 
Published: October 2006

AbstractMercapturic acid urinary excretion was followed in a control group and in chemical workers exposed to toxic and mutagenic compounds. Chemical workers had a significantly lower excretion of mercapturic acid when compared with controls. Smoking effects were not significant statistically. No correlation was found between urinary mutagenic activity and mercapturic acid urinary excretion.
Acetaminophen and its toxicity
Authors: Savides Michael C. , Oehme Frederick W. 
Published: October 2006

AbstractAcetaminophen (APAP) is considered one of the safest of all minor analgesics, but when taken in large doses (>10g) toxicity occurs. Severely poisoned patients experience hepatic and/or renal failure. The major metabolic pathway of APAP is formation of glucuronide and sulfate conjugates. A minor pathway is formation of a reactive metabolite that conjugates with glutathione (GSH). When GSH is depleted, the reactive metabolite causes necrosis of hepatic and other tissues. Treatment of APAP toxicity involves supplying alternate sulfhydryl donors or inhibiting oxidative formation of the reactive metabolite. Estimation of plasma APAP levels is necessary for effective treatment.
Embryotoxicity of sixteen industrial amines to the chicken embryo
Authors: Korhonen A. , Hemminki K. , Vainio H. 
Published: October 2006

AbstractSixteen amine compounds that are used in the rubber industry, and sodium nitrite, were tested on three‐day chicken embryos for embryotoxicity. The parameters measured were: early deaths recorded within two days of injection, late deaths of malformed embryos, late deaths of non‐malformed embryos and malformed survivors. The most embryotoxic chemicals were N‐phenyl‐N′‐isopropyl‐p‐phenylenediamine, N,N,N,‐triethylethylenediamine, N,N′,‐dicyclohexyl‐p‐phenyleneamine and triethylamine, with total effect ED50 values, including deaths and malformations, between 0.11 and 0.90 μmol per egg. The ED50 values for triethylenetetramine, N‐(1,3‐dimethylbutyl)‐N′‐phenyl‐p‐phenylenediamine, triethanolamine, N‐phenyl‐2‐naphtylamine, aniline and N‐nitrosodiphenylamine ranged from 1.1 to 7.0 μnol per egg. Sodium nitrite was the least potent, with an ED50 of 22 μmol per egg. Six chemicals produced no effects. They probably did not reach the embryo. The four most potent chemicals, together with aniline, caused the highest frequencies of malformations.
Binding of silicic acid by proteins and its relation to toxicity of silicate dusts
Authors: Misra Virendra , Rahman Qamar , Viswanathan P. N. 
Published: October 2006

AbstractA possible mechanism of biological effects of silicate dusts is the interaction between silicic acid and tissue constituents, and this has been studied in vitro. On incubating silicic acid with lung homogenate, appreciable amounts of silicon were recovered in the trichloroacetic acid precipitate in both organic solvent extract and residual protein. Polyvinyl pyrrolidone inhibited this interaction as well as reducing the dissolution of silicic acid from asbestos dust. The capacity of serum albumin to bind silicic acid was also observed. Chemical interaction between macromolecules and silicic acid could be one of the factors responsible for the biological effects of silicon—containing dusts.
Effects of partial hepatectomy on organ‐specific toxic response to 1,2‐dibromo‐3‐chloropropane (DBCP)
Authors: Kluwe William M. 
Published: October 2006

AbstractThe organ‐specific toxic potency of subcutaneously administered 1,2‐dibromo‐3‐chloropropane (DBCP) was compared in partially hepatectomized and sham‐operated rats over a dose range of 20–80 mg kg−1 to assess the roles of hepatic and extrahepatic metabolism in protection against acute renal and gonadal injury. Relative kidney weight and the severity of DBCP‐induced renal proximal tubular cell necrosis were increased in rats subjected to a partial (70%) surgical hepatectomy 48 h prior to treatment with DBCP at 80 mg kg−1. Relative liver weight was reduced by DBCP in the hepatectomized, but not in the shamoperated, rats. The severity of DBCP‐induced (80 mg kg−1) hepatocellular centrilobular necrosis was greater in hepatectomized than in sham rats. DBCP reduced the relative weights of the testis and epididymis in a progressive manner and produced dose‐dependent seminiferous tubular atrophy within 12 days of treatment. The morphologically apparent lesions of the testis and epididymis were enhanced by hepatectomy. The concentration of non‐protein sulfhydryl groups (NPS) in rat liver was increased by partial hepatectomy. Because of the resulting decrease in liver size, however, the total amount of hepatic NPS per kg body weight 48 h post‐surgery was lower than in sham rats. The surgery had no effect on renal, testicular or epididymal NPS concentrations or organ weights. Partial hepatectomy greatly increased pentobarbital and ethanol sleeping times, while sleep induction time for pentobarbital was decreased. These results are consistent with previous studies indicating that the metabolism of DBCP and conjugation with glutathione in the liver protects extrahepatic organs from toxic insult. Moreover, since extrahepatic toxicity was still evident, and often enhanced, after partial hepatectomy, extrahepatic necrogenic or cytotoxic responses would not appear to be dependent on hepatic metabolism of DBCP to a direct toxicant.
A comparative kinetics study of monochloramine and hypochlorous acid in rat
Authors: Abdel‐Rahman M. S. , Waldron D. M. , Bull R. J. 
Published: October 2006

AbstractThe problem of trihalomethane formation now exists with the use of chlorine (technically, a mixture of HOCl and OCl−, depending on pH) as a disinfectant in drinking water. Monochloramine (NH2Cl) may be considered as an alternative to HOCl as a disinfectant in public water supplies. This study was conducted to compare the kinetics of NH236Cl with HO36Cl in rats. The peak plasma levels of 36Cl occurred at 8 and 2 h for NH236Cl and HO36Cl, respectively. The distribution of NH236Cl and HO36Cl was highest in plasma, while the lowest activity was observed in the fat. The half‐life for 36Cl absorption was 2.49 and 2.16 h, while the elimination from plasma was 38.8 and 44.1 h after oral NH236Cl and HO36Cl treatment, respectively. Urinary excretion accounted for most of the 36Cl eliminated in both treatments.
Metabolic activation, detoxification and transformation studies with benzo[a]pyrene using rat and hamster organ cells in vitro
Authors: Raineri R. , Hillesund T. , Ernst M. K. , Cavanaugh D. M. , Poiley J. A. 
Published: October 2006

AbstractThe metabolism of benzo[α]pyrene (BP) by cultured kidney, liver, small intestine, lung and trachea from male Syrian golden hamsters and Sprague‐Dawley rats was compared. The metabolic capacity of intact cell systems was assessed by determining the formation of organic‐solvent‐soluble and water‐soluble metabolites, levels of covalent binding and levels of BP metabolites following separation using high‐pressure liquid chromatography. Hepatocytes from both species metabolized three to four times more BP than the other cells studied. Formation of water‐soluble metabolites by hepatocytes was at least 10 times that of the other cell types. Generally, hamster cells had greater metabolic capability than rat cells. Levels of covalent binding of metabolites of BP were at least 10 times greater in hepatocytes (uninduced) from both species than in the other cell types. Binding to hepatocytes and hamster embryo cells increased with incubation time coinciding with an increase in the formation of water‐soluble and diol metabolites. High levels of water‐soluble metabolites accompanied high levels of covalent, whole‐cell binding. Hamster embryo cells are transformed by BP without an exogenous metabolic activation system. The presence of hamster and rat hepatocytes inhibited transformation of hamster embryo cells by BP. This inhibition of transformation correlated with the increased rate of formation of water‐soluble detoxification metabolites by hepatocytes from both species. The high rate of formation of water‐soluble products by intact hepatocytes reflects the in vivo activity of liver cells. Use of hepatocytes in short‐term tests allows a system for carcinogen metabolism more closely representing that which is present in the whole animal.
Effects of daily interrupted nursing on body weight and survival of fischer 344 rat pups
Authors: Zelenak Janice P. , Snellings William M. 
Published: October 2006

AbstractThe effects on Fischer 344 rat pup body weight and survival were investigated when the dam was separated from her litter and deprived of food and water, approximately 7 h per day, from day 5 to day 21 of the postnatal period. This separation procedure simulates an inhalation reproduction study in whch only the dams are exposed to the test material during lactation. The dams and pups were observed daily for clinical signs, and the number of pups in each litter and their body weights were determined on days 4, 9, 14 and 21 after parturition. When pups and dams were so separated, there was no effect on pup survival, but the pup body weights were moderately lower for this group by the end of the postnatal observation period.
Carbon disulphide intrauterine sensitization
Authors: Tabacova Sonia , Nikiforov Bojidar , Balabaeva Liudmila 
Published: October 2006

AbstractThis study was designed to evaluate the effect of carbon disulphide (CS2) exposure during pregnancy in two subsequent generations. Albino rats (F1), which had been prenatally exposed by maternal inhalation to teratogenic (200 and 100 mgm−3) and subteratogenic (10 and 0.03 mg m−3) concentrations of CS2, were reared until maturity and mated to produce an F2 generation. During pregnancy the F1 females were again subjected to CS2 exposure at the same concentrations as the F0 females throughout gestation. Pre‐and postnatal development of F1 and F2 generations, as well as the corresponding maternal effects, were studied. Embryonic lethality, weight, congenital malformations, indices of lipid and energy metabolism, DNA and some liver drug metabolizing enzymes in maternal and fetal tissues were studied at term. Postnatal viability, physical and behavioral development, and hexobarbital sleeping time of the progeny were evaluated. Comparisons of CS2 effect on F1 and F2 generations were performed. A marked increase in CS2‐induced teratogenicity was found in the F2 generation, together with retarded development of MFO system and increased postnatal behavioral effects. The results point to intrauterine sensitization of progeny to CS2‐This effect is discussed in the light of possible interference of the agent with the hormonal programming of intrauterine development.
Effect of vehicle on the pharmacokinetics and uptake of four halogenated hydrocarbons from the gastrointestinal tract of the rat
Authors: Withey Jim R. , Collins Brian T. , Collins Peter G. 
Published: October 2006

AbstractA variety of low molecular weight aliphatic chlorinated hydrocarbons have a history of use in the processing of foods, and their presence in potable water supplies has also been demonstrated. In this study, the relative uptake of four different aliphatic chlorinated hydrocarbons (methylene chloride, dichloroethane, chloroform and trichloroethylene) was studied after administration, by intragastric intubation, at the same dose level as corn‐oil or aqueous solutions. Serial blood samples were collected over a 5‐h period and uptake was assessed as the calculated area under blood concentration‐time curves. A significant decrease in the rate and extent of uptake was observed for the compounds when administered as an oil solution as compared with an aqueous solution. Lower peak concentrations and an increase in the time taken to reach peak concentration, after dosing with corn oil solutons, was also observed.
Odor as an ald to chemical safety: Odor thresholds compared with threshold limit values and volatilities for 214 industrial chemicals in air and water dilution
Authors: Amoore John E. , Hautala Earl 
Published: October 2006

AbstractThe body of information in this paper is directed to specialists in industrial health and safety, and air and water pollution, who need quantitative data on the odor thresholds of potentially hazardous chemical vapors and gases. The literature, largely unorganized, has been reviewed for 214 compounds and condensed into tables based on consistent units. Data on the volatility, solubility, ionization and water‐air distribution ratio at 25°C are included. From the currently recommended threshold limit value (TLV), a safe dilution factor and an odor safety factor are calculated for each compound. The equivalent data are presented for both air and water dilutions of the chemicals. Available data are summarized on the variability of odor sensitivities in the population, and the increased odor concentrations that are required to elicit responses from persons whose attention is distracted, or who are sleeping. This information is reduced to calibration charts that may be used to estimate the relative detectability, warning potential and rousing capacity of the odorous vapors. Each compound has been assigned a letter classification, from A to E, to indicate the margin of safety, if any, that may be afforded by the odor of the compound as a warning that its threshold limit value is being exceeded.
Blood‐flow distribution in the mouse
Authors: Stott William T. , Dryzga Mark D. , Ramsey John C. 
Published: October 2006

AbstractBlood‐flow distribution was determined in pentobarbital‐anesthetized male B6C3F1 mice, using intracardially administered 141Ce‐radiolabelled microspheres (10μm). The proportion of cardiac output and blood flow per g tissue was determined in 18 organs and tissues, including the nasal cavity, lobes of the liver, individual kidneys and sections of the intestinal tract. To provide comparative data, blood‐flow distribution was also determined in pentobarbital‐anaesthetized male Fischer 344 rats. In general, there was close agreement between the distribution of blood flow between these two rodent species. The bladder and large intestine of mice appear to receive more, while the testes receive less, of the cardiac output than in rats. Rat liver and kidney, however, appear to receive approximately twice the amount of blood on a weight basis as in the mouse.
The neurotoxicity of trimethyltin chloride in hamsters, gerbils and marmosets
Authors: Brown A. W. , Verschoyle R. D. , Street B. W. , Aidridge W. N. , Grindley H. 
Published: October 2006

AbstractTrimethyltin chloride (TMT) was given to Syrian hamsters, gerbils and marmosets, and the changes in the brain were studied 1 day to 7 weeks later by light and electron microscopy. Within the marmoset brain, TMT was found to be uniformly distributed, similar to that in the rat. In all three species, signs of poisoning included whole‐body tremors and prostration, while death might occur in 3–4 days; in marmosets ataxia, agitation, aggression and occasional fits were also observed. Bilateral symmetrical neuronal necrosis and chromatolysis were seen in the majority, which involved the hippocampus, pyriform cortex, amygdaloid nucleus, neocortex, various brain stem nuclei and in marmosets the retina. The probably lethal dose of TMT in all three species is approximately 3 mg kg−1, while the LD50 for the rat is 12.6 mg kg−1. The lower figure is probably related to lack of binding to haemoglobin in contrast to the binding in the rat. TMT does not bind to human haemoglobin and thus the predicted lethal dose for humans may be about 3 mg kg−1 (15.1 μmolkg−1), while the dose required to produce neuronal damage could well be less.
Correction factors for determining body exposure from forearm percutaneous absorption data
Authors: Guy Richard H. , Maibach Howard I. 
Published: October 2006

AbstractEvaluation of toxic exposure via the skin is invariably based upon forearm percutaneous absorption data and an appropriate area multiplication factor. Published experimental data clearly show, however, substantial site variation in skin penetration such that the use of forearm data may produce an inaccurate prediction of total body exposure. Using literature results for cutaneous absorption as a function of anatomic position and accepted estimations of human body surface areas, correction factors for use with forearm penetration data have been evaluated. Calculations have been performed for an adult, a small child and a neonate. Examples of limited exposure to specific regions of the body have also been assessed relative to predictions based upon percutaneous absorption across forearm skin. It appears that the use of forearm skin penetration data alone underestimates body exposure by at least a factor of two.
Dimethoxyethylphthalate metabolism: Teratogenicity of the diester and its metabolites in the pregnant rat
Authors: Campbell J. , Holt Daphne , Webb M. 
Published: October 2006

AbstractThe rat foetus, in contrast with the maternal liver and placenta, has little or no ability to hydrolyse di‐(2‐methoxyethyl)‐phthalate (DMEP) to mono‐2‐methoxyethylphthalate (MMEP). At short times after the administration of DMEP to the dam on the 14th day of gestation, however, both the di‐ and mono‐ester are present in the foetus. Clearance of total phthalate from the foetus and placenta, is rapid and the foetal burden is reduced by 96% between 45 min and 4h. Although MMEP, when injected into the dam at the same molar dose level, crosses the placenta, its concentration in the foetus is lower than that after the injection of DMEP. MMEP (2.49 mmol kg−1), is no teratogenic when administered as an aqueous solution of the sodium salt on day 8, 10, 12 or 14 of gestation, in contrast with the same molar dose of the liquid DMEP. The alcohol, 2‐methoxyethanol (ME), when administered as a single injection at this dose level (2.49 mmol kg−1), however, is highly teratogenic and its effects cannot be differentiated clearly from those of DMEP. These results, which indicate the possibility that ME, derived by metabolism of DMEP, may be the teratogenic agent, suggest that both the rate of hydrolysis to the monoester and the chemical properties of the liberated alcohol, could be important determinant factors in the teratogenic activities of different phthalate diesters.
Differentation of rat embryo cells in culture: Response following acute maternal exposure to teratogens and non‐teratogens
Authors: Flint O. P. , Orton T. C. , Ferguson R. A. 
Published: October 2006

AbstractAn in vivo–in vitro test system with high sensitivity to teratogens has been developed and validated. A single acute intra‐peritoneal injection of teratogens (18) and non‐teratogens (13) was administered to pregnant rats on the 12th day after fertilisation, and uteri were removed after 16 h by laparotomy. 34–36 Embryos somites were selected, and mid‐brain (CNS) and fore‐limb buds (LB) were dissected free and dispersed as single‐cell suspensions in Ham's F12 culture medium. The cells were cultured as micromass cell islands for 5 days, and discrete foci of neuronal cells differentiated in CNS cultures and chondrocytes in LB cultures. After 5 days, differentiation as determined by number of stainable foci of differentiated cells and 3H‐GABA incorporation in CNS or 35SO4 incorporation in LB and growth (as determined by total protein) were measured. Both differentiation and growth of CNS and LB cultures were markedly reduced following exposure of the dam to teratogens, whereas no significant effect was observed with non‐teratogens. One teratogen (amaranth) and one non‐teratogen (nitrilotriacetic acid) were classified as false negative and positive, respectively; the sensitivity of the test (proportion of teratogens correct) was therefore 92% and the specificity (proportion of non‐teratogens correct) was 94%. Inhibition of growth and differentiation in the rat embryo cell cultures following maternal exposure forms the basis of a short‐term in vitro test for teratogens.