bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dominant lethal study of sulfur mustard in male and female rats
Authors: Sasser L. B. , Cushing J. A. , Dacre J. C. 
Published: October 2006

AbstractSulfur mustard (HD) (bis(2‐chloroethyl)sulfide) is a strong alkylating agent with known mutagenic and suspected carcinogenic properties, but occupational health standards have not been established. The purpose of this study was to determine the dominant lethal effect in male and female rats dosed orally with HD, for which currently available data are ambiguous.Sprague‐Dawley rats of each sex, 6–7 weeks old, were orally administered 0, 0.08, 0.20 or 0.50 mg kg−1 HD 5 days a week for 10 weeks, after which dominant lethal studies were conducted during the post‐exposure period. The studies were conducted in two phases: a female dominant lethal phase in which treated or untreated males were mated with treated females and their fetuses were evaluated 14 days after copulation; and a male dominant lethal phase in which treated males cohabited with untreated females for 5 days and fetuses were evaluated 14 days after the mid‐point of the week of cohabitation, for each of 10 weeks. In addition, motility, population size and morphology were measured in sperm obtained from the cauda epididymis.Parental growth rates were reduced in both sexes treated with the high level of HD. Female dominant lethal effects were not observed, although significant male dominant lethal effects were observed in HD‐exposed male rats mated to untreated females at 2 and 3 weeks' post‐exposure. These effects, which included increases of early fetal resorptions and preimplantation losses and decrease in total live embryo implants, were most consistently observed at a dose of 0.50 mg kg−1. A significant P(P<0.05) increase in the percentage of abnormal sperm was detected in males exposed to 0.50 mg kg−1 HD. The timing of dominant lethal effects is consistent with an effect during the post‐meiotic stages of spermatogenesis, possibly involving the generally sensitive spermatids.
Kidney function in male and female rats chronically exposed to potassium dichromate
Authors: Vyskočil A. , Viau C. , Čížková M. , Truchon G. 
Published: October 2006

AbstractMale and female Wistar rats were given 25 mg I−1 chromium (as potassium dichromate) in drinking water for 6 months. Lactate dehydrogenase, lysozyme, total proteins, N‐acetyl‐β‐D‐glucosaminidase, albumin and β2‐microglobulin (β2‐m) were measured in 24‐h urine after 3 and 6 months of exposure. Body and kidney weight and chromium excretion were also examined.Except for the chromium excretion, no statistically significant changes were observed in the exposed male rats. In female rats there were significant increases in the urinary excretion of albumin after 3 and 6 months of exposure and the urinary excretion of β2‐m after 3 months of exposure.
Risk assessment and management of chemical contaminants in fishery products consumed in the USA
Authors: Ahmed Farid E. , Hattis Dale , Wolke Richard E. , Steinman David 
Published: October 2006

AbstractIn the USA a small proportion of fishery products are contaminated with appreciable amounts of potentially hazardous contaminants. However, risks to consumers are not generally high. Inorganic contaminants with the greatest potential for toxicity are antimony, arsenic, cadmium, lead, mercury, selenium and sulfites. Among organic compounds, polychlorinated biphenyls, dioxins, several chlorinated hydrocarbon insecticides, certain processing‐related and aquaculture‐related contaminants pose potential risks for consumers.Log‐normal distributions appear to provide good descriptions of the pattern of variation of contaminant concentrations among different geographic areas, and some contaminants (mostly organic) appear to be much more variable than others. This variability offers a solution for reduction of exposure through restricting the harvest of aquatic organisms from specific sites, and by excluding certain species.It is recommended that: (i) existing State and Federal regulations and environmental monitoring be strengthened and enforced to minimize contamination of the aquatic environment; (ii) a program of shared responsibility be instituted, where Federal agencies develop a set of monitoring and inspection practices and state agencies assume responsibility for primary control, site closures and advisories issue; (iii) research and public education by government agencies and health professionals be expanded to determine actual risks and approaches to manage them; (iv) mandatory labeling be considered for specific contaminants; (v) a better system requiring international agreements be developed in order to minimize the differences among various national regulatory approaches.
Toxicity of diethanolamine. 1. Drinking water and topical application exposures in F344 rats
Authors: Melnick Ronald L. , Mahler Joel , Bucher John R. , Thompson Morrow , Hejtmancik Milton , Ryan Michael J. , Mezza Lawrence E. 
Published: October 2006

AbstractToxicology studies of diethanolamine were conducted in male and female F344 rats for 13 weeks' duration to characterize and compare effects of exposure in the drinking water with those caused by topical application. Doses of diethanolamine ranged from 160 to 5000 ppm in the drinking water study (equivalent to daily doses of 25–440 mg kg−1 in males and 15–240 mg kg−1 in females) and from 32 to 500 mg kg−1 in the topical application study. Dose‐dependent toxic effects due to exposure to diethanolamine included hematological changes (a poorly regenerative, microcytic anemia), as well as toxic responses in the kidney (increased weight, tubular necrosis, decreased renal function, and/or tubular mineralization), brain and spinal cord (demyelination), testis (degeneration of the seminiferous tubules) and skin (site of application: ulceration, inflammation, hyperkeratosis and acanthosis). A no‐observed‐adverse‐effect level was not achieved for hematological changes, nephropathy or hyperkeratosis of the skin. Differences in dose‐response between the drinking water and topical application exposures were attributed largely to the limited dermal absorption of this chemical.
Toxicity of diethanolamine. 2. Drinking water and topical application exposures in B6C3F1 mice
Authors: Melnick Ronald L. , Mahler Joel , Bucher John R. , Hejtmancik Milton , Singer Allen , Persing Ronald L. 
Published: October 2006

AbstractToxicology studies of diethanolamine were conducted in male and female B6C3F1 mice to characterize and compare effects of exposure in the drinking water with those caused by topical application and to compare responses in mice to those observed in rats. Each study consisted of five dose groups plus controls and the size of each group was 10 animals per sex. Doses of diethanolamine ranged from 630 to 10 000 ppm in the drinking water study (approximately equivalent to daily doses of 100–1700 mg kg−1 in males and 140–1100 mg kg−1 in females) and from 80 to 1250 mg kg−1 in the topical application study. Exposure to diethanolamine caused dose‐dependent toxic effects in the liver (hepatocellular cytological alterations and necrosis), kidney (nephropathy and tubular epithelial necrosis in males), heart (cardiac myocyte degeneration) and skin (site of application: ulceration, inflammation, hyperkeratosis, and acanthosis). Cytological alterations in the liver consisted of multiple hepatocyte changes, including enlarged cells that were frequently multinucleated, increased nuclear pleomorphism, increased eosinophilia and disruption of hepatic cords. A no‐observed‐adverse‐effect level (NOAEL) was not achieved for hepatocellular cytological alterations or for acanthosis in the skin.
Effect of tordon 2,4‐D 64/240 triethanolamine BR on the energy metabolism of rat liver mitochondria
Authors: Pereira Luiz Fernando , Campello Annibal P. , Silveira Orieta 
Published: October 2006

AbstractTordon herbicide, which is a mixture of 4‐amino‐3,5,6‐trichloropicolinic acid (picloram) and 2,4‐dichlorophenoxyacetic acid (2,4‐D), depresses the phosphorylation efficiency of the rat liver mitochondria, as inferred from the decrease of the respiratory control coefficient and the ADP/O ratios when NAD+‐dependent substrates were used; NADH oxidase and NADH cytochrome c reductase were also inhibited, without any effect on the other enzymatic complexes of the respiratory chain. Tordon (66.2 nmol picloram + 270 nmol 2,4‐D mg−1 protein) affected the amplitude of swelling induced by glutamate, succinate, (N,N,N′,N′‐tetramethyl‐p‐phenyldiamine + sodium ascorbate and ATP. These results characterize an interaction of Tordon with complex I of the respiratory chain and also a partial collapse of the proton motive force of the mitochondrial inner membrane without affecting its elasticity.
Cardioteratogenic dose of ethanol reduces both lactic dehydrogenase and succinic dehydrogenase activity in the bulbar ridges of the embryonic chick heart
Authors: Bruyere Harold J. , Stith Charles E. , Thorn Thomas A. 
Published: October 2006

AbstractIt has been established previously that the chick embryo is an appropriate model for studying the pathogenesis of ethanol‐induced ventricular septal defect and that the growth and fusion of the proximal bulbar ridges are critical to ventricular septation within the embryonic heart. To determine whether enzyme activity was altered significantly in bulbar ridges in response to a cardioteratogenic dose of ethanol, we injected 0.32 ml of 50% ethanol in chick Ringer's saline (CRS) into the air cells of 3‐day‐old chick embryos (72–84 h incubation, Hamburger‐Hamilton stages 18–19, Dekalb Delta strain). Embryos were harvested 48–60 h after treatment (stages 26–27). Hearts were removed, frozen and sectioned, and the tissues were processed for enzyme histochemical demonstrations of lactic and succinic dehydrogenase. Twelve ethanol‐treated embryos and 12 CRS‐treated controls were compared for lactic dehydrogenase (LDH) levels. Fourteen ethanol‐treated embryos and 14 controls were compared for succinic dehydrogenase (SDH) levels. Formazan deposits were quantified by means of computer‐assisted microdensitometry. Our results showed that ethanol decreased the mean LDH activity level by 36.3% (P = 0.05) and the mean SDH level by 40.8% (P < 0.02). Furthermore, ethanol significantly reduced LDH activity in 41.7% of the matched embryo pairs and significantly reduced SDH activity in 57.1% of the matched embryo pairs. Although some investigators have proposed that a disturbance in neural crest cell migration plays a major role in the pathogenesis of ethanol‐induced cardiac malformations, this study provides evidence that the bulbar ridges of the embryonic heart are also potential target tissues for ethanol.
Cardioteratogenic dose of ethanol in the chick embryo results in albumin ethanol concentrations comparable to human blood alcohol levels
Authors: Bruyere Harold J. , Choudhury Somesh , Nelson Eric , Stith Charles E. 
Published: October 2006

AbstractThree‐day‐old chick embryos (Hamburger‐Hamilton stages 18–19) were exposed to a dose of ethyl alcohol (0.32 ml of 50% ethanol) that causes cardiac malformations in 96.6% of the animals. Ethanol was administered into the air sac after 72–80 h of incubation. Samples of albumin at the opposite pole of the egg were drawn 0–50 h after treatment and quantitated for ethanol concentration with capillary gas‐liquid chromatography. Ethanol concentrations in the albumin increased significantly (P < 0.05) at 2, 5 and 15 h after injection of ethanol, reached a maximum mean ethanol concentration at 20 h (217.3 ± 23.5 mg dl−1), decreased significantly at 30 h to 175.4 ± 27.5 mg dl−1, then increased again and stabilized at 40–50 h. Individual sample concentrations ranged from 0 mg dl−1 (at 0.5–2 h) to 286.5 mg dl−1 at 40 h. Ethanol concentrations in the albumin were comparable to human blood alcohol levels during intoxication ( > 150 mg dl−1). Our results suggest that a potent cardioteratogenic dose of ethanol in the chick embryo is reasonable in terms of potential human embryo exposure.
Isoflurane increases the anaerobic metabolites of halothane
Authors: Rahman Mustafizur , Fujii Kohyu , Sato Nobuyoshi , Yuge Osafumi 
Published: October 2006

AbstractThe effect of isoflurane on the anaerobic metabolism of halothane to chlorodifluoroethene (CDE) and chlorotrifluoroethane (CTE) was studied with microsomes of guinea pig liver by gas chromatography. The reaction mixture used to measure the end products of anaerobic metabolism consisted of a microsomal suspension, 3 mM NADPH, halothane and isoflurane (except in control groups) in 0.1 M potassium phosphate buffer solution (pH 7.4). The Km values for CDE formation were 601.61 ± 266.91, 254.22 ± 86.58, 257.92 ± 129.11, 268.55 ± 125.66 and 319.22 ± 86.76 μM (mean ± SD, n = 5) at 0 mM (0%), 0.12 mM (0.26%), 0.29 mM (0.64%), 0.58 mM (1.30%) and 1.16 mM (2.59%) isoflurane, respectively. The Km values for CTE formation were 1204.74 ± 551.64, 553.75 ± 177.89, 521.14 ± 249.77, 560.67 ± 229.61 and 711.05 ± 317.13 μ (n = 5) at 0 mM (0%), 0.12 mM (0.26%), 0.29 mM (0.64%), 0.58 mM (1.30%) and 1.16 mM (2.59%) isoflurane, respectively. In contrast, the Vmax values for CDE and CTE formation at these isoflurane concentrations were not significantly different than in the control groups. In this study the production of CDE and CTE was significantly (P < 0.05) increased by isoflurane, at concentrations up to 0.58 mM (1.30%).
Coronary vessel alterations following chronic carbon monoxide exposure in the adult rat
Authors: Penney David G. , Giraldo Alvaro A. , Van Egmond Eve M. 
Published: October 2006

AbstractAdult male rats were exposed to 500 ppm CO continuously for 30 days, while litter‐mate controls remained in room air (AIR). Heart weight‐to‐body weight ratio and hematocrit were increased significantly. Right ventricle (RV) free wall thickness was increased significantly as was right to left heart diameter and average heart diameter. Cross‐sectional areas of the left ventricle (LV) free wall, interventricular septum (S) and RV midway between the apex and base were increased significantly. Morphometric analysis of the CO‐exposed and AIR hearts revealed no significant differences in the number of small (27–114 μm) or larger (>114 μm) blood vessels in any region; however, there was a trend towards an increased number of the smaller vessels, both arterioles and venules, in the CO‐exposed rats. The larger arteries in the S and RV were significantly larger in the CO‐exposed rats. There was a significant overall effect of CO on larger artery diameter across all heart regions, consistent with the appearance of heart radiographs taken. There were no differences in the diameter of the small vessels in any region of the heart between the CO‐exposed and AIR rats. The vessel cross‐sectional area of the larger vessels tended to be increased in all regions of the heart. The cross‐sectional area of the large arteries in the LV was increased significantly. Arterial wall thickness was decreased significantly in RV and there was a significant overall effect of CO in decreasing wall thickness and the ratio of wall thickness‐to‐vessel luminal diameter in these vessels. No vascular pathology was observed. The results of this study suggest changes in coronary vessel architecture during chronic CO‐induced cardiac hypertrophy and are consistent with earlier hemodynamic and morphometric studies of CO‐exposed hearts.
Validation of an improved nose‐only exposure system for rodents
Authors: Pauluhn J. 
Published: October 2006

AbstractSeveral types and modifications of nose‐only inhalation chambers for exposing rodents are described. The improvement of this ‘flow‐past’ ‐like nose‐only exposure system is that it is modular, i.e. it can be used for acute studies with a maximum of 20 rodents (one segment) or for chronic inhalation studies with 100 (or more) rodents per chamber with five (or more) segments. Another goal was to design a nose‐only exposure system that provides maximal computer support and automatization, as well as robust aerosol collection conditions. The evaluation of the five‐segment chamber, charged with 98 rats, revealed that a flow rate of 0.75 I air min−1 or approximately 2.5 times the rat minute ventilation volume per exposure port is sufficient to provide homogeneous temporal and spatial exposure conditions. Also, the aerosol size distribution was constant throughout the chamber. Experimental data suggest that computer‐controlled sampling of the test atmosphere up to ca. 6 I air min−1 did not alter the flow dynamics of the exposure system. The nose‐only inhalation chamber developed is suitable for short‐term and long‐term inhalation toxicity studies using small laboratory rodents with minimal consumption of test compound.
Flow cytometric analysis of the direct toxic effects of paraquat on cultured MDCK cells
Authors: Yamagami Kazunobu , Matsubara Mineo , Kitazawa Yasuhide , Takeyama Naoshi , Tanaka Takaya , Kawamoto Keiji 
Published: October 2006

AbstractWe used flow cytometry to assess the cell cycle kinetics of cultured Maden Darby canine kidney cells after exposure to paraquat. Fluorescein diacetate fluorescence was used as a marker of cell viability, while bromodeoxyuridine incorporation was detected with a monoclonal antibody and propidium iodide staining to assess DNA synthesis. Flow cytometry was performed immediately, 48 h and 96 h after exposure to paraquat for 24 h. Lactate dehydrogenase release was also measured to determine the extent of cytolysis. Flow cytometry of paraquat‐treated cells showed a marked increase of the S phase population immediately after exposure, at a time when there was no increase of lactate dehydrogenase release. In contrast, the cell cycle profile returned towards normal at 48 and 96 h after paraquat exposure, but lactate dehydrogenase release increased. These findings indicate that paraquat arrested cells in the S phase and that inhibition of DNA synthesis by this agent appeared to influence cell viability because S phase block occurred before cytolysis. In addition, this method proved useful for assessing the effects of paraquat on DNA synthesis by cultured cells.
Cytogenetic studies on commercial hexane solvent
Authors: Daughtrey W. C. , Putman D. L. , Duffy J. , Soiefer A. I. , Kirwin C. J. , Curcio L. N. , Keenan T. H. 
Published: October 2006

AbstractCommercial hexane is a solvent mixture of six‐carbon isomers, consisting principally of n‐hexane, 3‐methylpentane, methylcyclopentane and 2‐methylpentane. The potential of commercial hexane to produce chromosome aberrations was evaluated in both an in vitro assay using Chinese hamster ovary (CHO) cells and an in vivo cytogenetics assay using Sprague‐Dawley rats. The CHO cells were exposed to media containing commercial hexane at concentrations of 0.014–0.42 μl ml−1 in the presence and absence of an S‐9 activation mixture. Cellular toxicity was observed at the higher dose levels, but no increase in chromosome aberrations was observed in either the non‐activated or S‐9‐activated systems. For the in vivo cytogenetics assay, rats were exposed nose‐only for 6 h per day for 5 consecutive days to commercial hexane vapor at target concentrations of 900, 3000 and 9000 ppm. Bone marrow cells were collected at 6 and 24 h after the midpoint of the last exposure. Metaphase cells were examined microscopically for chromosome aberrations. No statistically significant increases in aberrant cells were observed in the commercial hexane‐exposed animals of any dose group at either of the bone marrow harvest times. In conclusion, commercial hexane did not produce chromosomal mutations under the conditions of these studies.
Snake poisoning in rural Zimbabwe—A prospective study
Authors: Nhachi Charles F. B. , Kasilo Ossy M. J. 
Published: October 2006

AbstractOver a period of 2 years (January 1991 to December 1992) 274 cases of snake bite were admitted to hospital in the eight provinces of Zimbabwe. Of these patients, 54% were males and 88% belonged to the 6–40‐year age group. Five deaths (1.8% of the total cases) were reported. The majority of snake bites (63%) occurred at night (between 6.30 p.m. and midnight) and over 74% took place during the hot rainy season, i.e. between November and April. In over 58% of the cases the victim accidentally stepped on the snake, the snake being cobra in 37%, puff adder in 20% and the black and green mamba in 18% of the cases. Most of the bites occurred on the leg, below the knee.Treatment of snake envenomation consisted mainly of the administration of antibiotics (151 cases), analgesics (144 cases), antivenom tropical snake polyvalent (ATT) (89 cases), antitoxoid tetanus (TT) (61 cases), antihistamines (47 cases) and traditional medicines (43 cases). This study indicates that snake envenomation in rural Zimbabwe is common but fatalities are relatively rare.
Initial interlaboratory validation study of FETAX: Phase I testing
Authors: Bantle John A. , Rayburn James R. , Burton Dennis T. , Turley Steven D. , Dawson Douglas A. , Dumont James N. , Finch Robert A. , Maurice Margaret A. , Fort Douglas J. , Linder Greg , Buchwalter David 
Published: October 2006

AbstractAn interlaboratory validation study was undertaken to evaluate the repeatability and reliability of the Frog Embryo Teratogenesis Assay‐Xenopus (FETAX), which is a whole embryo developmental toxcity screening assay. A three‐phase experimental program with seven participants was carried out. Phase I was a training and protocol evaluation phase where the identity of the three test materials was known. Hydroxyurea, isoniazid and 6‐aminonicotinamide were tested in Phase I. Because the chemicals has been tested previously in FETAX, the same concentrations needed to establish the 96‐h median lethal concentration (LC50) and the concentration inducing malformations in 50% of the surviving embryos (EC50) were used by all laboratories. The results of Phase I are presented in this report, and FETAX has proved to be as repeatable and reliable as many other bioassays. Some excess variation was observed in individual laboratories. Some of this variation may have been due to training difficulties. One change in protocol design necessitated by this study was the use of 6‐aminonicotinamide as a reference toxicant. While 6‐aminonicotinamide provided excellent concentration‐response data in most laboratories, the protocol was written too strictly based on historical FETAX data. Phases II and III are currently in progress.
Sensitivity of adenosine triphosphatases in different brain regions to polychlorinated biphenyl congeners
Authors: Maier William E. , Kodavanti Prasada Rao S. , Harry G. Jean , Tilson Hugh A. 
Published: October 2006

AbstractPolychlorinated biphenyl (PCBs) mixtures contain a number of different congeners, some of which have been proposed to be neuroactive. Recent studies have suggested that ortho‐substituted PCBs may be neuroactive, while ‘dioxin‐like’ non‐ortho‐substituted congeners are not. This study compared the in vitro effects of a putative neuroactive ortho‐biphenyl (2,2′‐dichlorobiphenyl; DCBP) with that of a putative non‐neuroactive congener lacking ortho‐chlorine substitutions (3,3′,4,4′,5‐pentachlorobiphenyl; PCBP) on Mg2+‐ATPase activity in mitochondrial and synaptosomal preparations from striatum, hypothalamus, cerebellum and hippocampus. In these studies, DCBP significantly inhibited oligomycin‐sensitive (OS) Mg2+‐ATPase activity in all four brain regions in a concentration‐dependent manner; PCBP, on the other hand, had no effect on OS Mg2+‐ATPase activity in any brain region examined at concentrations up to 100 μM. The striatum, a dopamine‐rich region, was not preferentially sensitive to the effects of DCBP. Furthermore, DCBP did not inhibit synaptosomal Na+/K+‐ATPase activity, suggesting a specificity of action on OS Mg2+‐ATPase. These data support previous structure‐activity relationships, suggesting that ortho‐substituted PCB congeners are neuroactive while non‐ortho‐substituted congeners are not. Disruption of mitochondrial oxidative energy production may play a role in the neuroactivity of ortho‐chlorinated PCBs.