bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of polchlorinated paraffins on hepatic, renal and intestinal biotransformation rates in comparison to the effects of polychlorinated biphenyls and naphthalenes
Authors: Ahotupa Markku , Hietanen Eino , Mäntylä Eero , Vainio Harri 
Published: October 2006

AbstractPolychlorinated paraffins (PCPs), biphenyls (PCBs) and naphthalenes (PCNs) were compared as inducers of drug‐metabolizing enzymes in different rat tissues. Two different chain lengths (C11 or C20) and chlorination degrees (40 or 70% chlorine) of PCPs, two preparations of PCNs (50–70% chlorine), and one PCB preparation (54% chlorine) were used. The compounds were administered intraperitoneally to rats, and the activities of various drug‐metabolizing enzymes were analysed in hepatic and renal microsomes and in the post‐mitochondrial supernatant of the small intestinal mucosa. PCB and PCNs were potent inducers of both hepatic and renal drug‐metabolizing enzyme activities, whereas PCPs produced only minor changes in these activities. When compared with each other, PCNs were somewhat stronger inducers than PCB. The enhancement of enzyme activities in the liver was different from that of the kidney. The maximal induction of aryl hydrocarbon hydroxylase was 4.8‐fold in the liver and 7.2‐fold in the kidney, that of ethoxy‐coumarin deethylase 12‐fold in the liver and 53‐fold in the kidney, while the activity of UDP glucuronosyl‐transferase was increased only in the liver (maximally 4.5‐fold). In small intestinal mucosa, there were only moderate changes in the activities of drug‐metabolizing enzymes.
The hazards of cadmium in man and animals
Authors: Winter Hans 
Published: October 2006

AbstractThe health hazards of cadmium have attracted increased attention since the rock‐soil‐plant‐animal‐man relationship became better known, and when it was realized that low doses are cumulative over a very long time and that increasing industrial pollution may endanger the general population. Major sources are mining and smelting, metal coating, welding, incineration of refuse, fossil fuels and use of sewage sludge as fertilizer. Intoxication usually results from ingestion or inhalation, but the pathogenesis is not well understood. With chronic intoxication, the critical organ is the kidney, where one third of the body cadmium may accumulate. Apart from diseases so far recognized in man, a large number of pathological conditions have been produced in experimental animals, including congenital abnormalities, ovarian, testicular and brain lesions, as well as interference with the immune system. Their full significance for man is not yet known. Cadmium plays no useful role in the organism and its intake should be limited as much as possible, although being ubiquitous it cannot be completely eliminated. Legislation for maximum permissible levels in different food items was attempted, but is not workable and is not in the best interest of the consumer. Instead, the whole food basket of the consumer should be monitored to limit weekly intake to prescribed levels. In addition, hygienic measures should be encouraged, including cleaning, peeling or blanching of fruit and vegetables, removal of outer leaves of cabbage and lettuce to eliminate the effects of aerial pollution, discretion in using sewage sludge as fertilizer, washing hands and possibly avoiding excessive consumption of kidneys and livers.
Heavy metals in Tasmanian shellfish 1 — monitoring heavy metal contamination in the Derwent estuary: Use of oysters and mussels
Authors: Cooper R. J. , Langlois D. , Olley June 
Published: October 2006

AbstractThe contamination of an estuary with heavy metals by a single large ore processing plant provided a unique opportunity to assess the use of mussels and oysters as indicators of heavy metal contamination. Field accumulation and depuration experiments, variation of metal content with size and prediction of water movements are described from shellfish surveys covering the Derwent River and adjacent coastal waters. Oysters were found to be suitable for monitoring zinc, cadmium, lead and copper contamination. Mussels were also suitable for monitoring zinc, cadmium and lead, but in this instance were found unsuitable for monitoring copper as the surveys indicate that copper accumulation is suppressed in mussels in a contaminated environment. The rate of accumulation and depuration of metals by oysters and mussels in field trials has been related to the anatomy of the animals and the sequestering of some metals in granulocytes. Uneven metal distribution between gonad and other tissues has been found to cause seasonal variation of heavy metals in oysters.
Origin of mutagenicity of welding fumes in S. typhimurium
Authors: Stern R. M. , Thomsen E. , Anderson M. , Kiel P. , Larsen H. 
Published: October 2006

AbstractThe origin of mutagenicity in S. typhimurium in response to exposure to welding fumes, a complex mixture of metallic oxides and other inorganic compounds, was studied through the quantitative use of the histidine revertant Salmonella microsome test of Ames. Dose‐response experiments and factorial design studies independently showed the mutagenic activity to be due to the presence of soluble Cr(VI). A rate of 65 ± 15 revertants per plate per μg Cr(VI) was found for all fumes produced by the metal inert gas welding of stainless steel. A significantly reduced rate was found for manual metal arc welding fumes. The presence of other metals in low oxidation states (e.g. Fe(0), Fe(II), Al(0)), results in a significant reduction of the Cr(VI), accompanied by a corresponding decrease of the absolute revertant rate per unit fume mass.
Toxicity of alcide
Authors: Abdel‐Rahman Mohamed S. , Gerges Sammy E. , Alliger Howard 
Published: October 2006

AbstractAlcide is now used as a liquid sterilizer in an ultrasonic cleaner. It is excellent for herpes, fungus of the fingernail, warts and treatment of burn infection. The active ingredients (AI's) in this compound are sodium chlorite (ClO2−) and lactic acid. Studies were conducted to determine the toxicity of Alcide in its liquid and gel forms. The oral lethal doses after 14 days (LD50) in female and male rats were 340 and 292 mg kg−1 (AI), respectively. No mortality occurred during the acute dermal toxicity study. The ocular irritation study in rabbits indicated redness in the conjunctivae within 1 h which became normal after 24 h. The cornea and iris remained without changes during the observation period. The guinea pig sensitization study revealed the occurrence of reversible necrosis after 3 days. On day 11, healing began and was completed by day 15 after the intradermal injection. No significant changes were observed in red blood cell compartments, glutathione levels, hemolysis, methemoglobin and blood chemistry in rabbits treated daily with 0.5, 1.0 or 2.0 (gm kg−1) Alcide for 1 month using intact and abraded skin.
Comparison of toxic and transforming effects of ten environment‐related polycyclic hydrocarbons, including benzo [a] pyrene, on Fetal Hamster Lung Cell Cultures
Authors: Emura M. , Richter‐Reichhelm H.‐B. , Schneider P. , Schoch C. , Mohr U. 
Published: October 2006

AbstractStandardized procedures were developed to compare quantitatively the toxic and transforming effects of ten environment‐related polycyclic aromatic hydrocarbons (PAH's) using early passage mixed cultures of fetal Syrian golden hamster lung cells. Evaluation of toxicity was attempted by applying a linear regression to the relative number of surviving colonies. Transformation data were fitted satisfactorily to the one‐hit model. Used as a monitor compound in each subexperiment, benzo[a]pyrene (BaP) showed dose‐related colony reduction (0.01–0.5 μg ml−1). Benzo[b]fluoranthene (BbF), indeno[1,2,3‐cd]pyrene (IcdP), benzo[k]fluoranthene (BkF) and benzo[e]pyrene (BeP) were generally colony enhancing at dose ranges up to 1.0 μg ml−1. Fluoranthene (FLT), pyrene (PYR), chrysene (CHR), benzo[ghi]perylene (BghiPL) and benz[a]anthracene (BaA) were neither stimulatory nor inhibitory to colony formation. For transformation induction, BaP was over 14‐fold more effective than BbF, IcdP or BaA. The other PAH's showed no transformation.
Relationship between solubility and hemolytic effects of toxic dusts
Authors: Singh S. V. , Das Ballabh , Rahman Qamar 
Published: October 2006

AbstractTwo varieties of native and chemically treated slate dust were tested in vitro for their hemolytic effects and the extent of silicic acid dissolution in various physiological fluids. The extent of hemolysis was found to be proportional to the degree of dissolution of dust constituents. Membrane lysis by the dust appeared to be prevented by coating it with polyvinyl pyrrolidone, serum proteins and pulmonary lavage lipids. The significance of the findings is discussed.
Initiation/promotion studies with coal‐derived liquids
Authors: Mahlum D. Dennis 
Published: October 2006

AbstractFractions derived from solvent‐refined coal‐II (SRC‐II) heavy distillate (HD) were tested for their skin tumor initiating activity. Basic (BF), basic tar (BTF), neutral tar (NTF) and polynuclear aromatic (PNA) fractions were prepared from HD by solvent extraction. These fractions were tested for their initiating activities by applying a single dose to the shaved back of male, CD‐1 mice (Charles River, Portage, MI). Positive control groups were initiated with either dimethylbenz[a]anthracene (DMBA) or benzo[a]pyrene (BaP). Two weeks after initiation, all mice received twice weekly applications of 5 μg of phorbol myristate acetate (PMA) for a period of 24 weeks. Papillomas were noted and recorded for each animal at the time of PMA application. Heavy distillate and its fractions all showed initiating activity. However, the incidence of mice with tumors, the rate of tumor appearance and the total number of tumors varied with the test material. The tumor responses after initiation with HD, NTF and BTF were similar to that found with BaP, but lower than that with DMBA. Somewhat lower activity was found for BF and PNA. Even lower activity was found with a distillate boiling from 800 to 850°F and no activity was found with a 300 to 700°F distillate. These data are in general agreement with the results of long‐term, skin painting assays, suggesting that initiation/promotion (I/P) may be useful for studying the tumorigenicity of coal‐derived materials.
Pharmacokinetics of methylmercury in sheep
Authors: Kostyniak Paul J. 
Published: October 2006

AbstractA preliminary study of the pharmacokinetics of methylmercury was performed in sheep after a single intravenous dose of 203 Hg‐labeled methylmercury. Blood samples were taken periodically, and plasma and whole blood 203Hg were determined. Blood and plasma 203Hg concentrations exhibited a biphasic exponential decline. The half‐time for the major component was 14.6 days for plasma 203Hg and 14.1 days for whole blood. There was a uniform distribution of 203 Hg between red cells and plasma throughout the study. A red cell to plasma concentration ratio of 14.9:1 was obtained, with approximately 88% of the 203 Hg in blood associated with the red cell fraction. Both the feces and the wool represented major routes of excretion. Approximately 18% of the dose was present in the wool taken on day 8. This is compared with a total excretion in the feces of 11.5% of the dose over the same time course. The total of 29.5% compares favorably with a reduction of 32.5% in the terminal component of the whole blood curve. Sequential analysis of wool from the root end revealed increasing concentrations of 203 Hg to a peak. Using the first appearance of the 203 Hg label in the wool as a marker to determine the wool growth rate, the 203 Hg in wool shewed an exponential decline with a half‐time similar to that seen for whole blood and plasma. The wool to blood ratio was estimated to be approximately 120:1. Tissue analysis at sacrifice revealed a rather uniform distribution of 203 Hg label in the brain. Somewhat lower levels were observed in the spinal cord and ganglia. Kidney had the highest 203 Hg concentration, and edible muscle had approximately six times the concentration measured in blood. The concentration of 203 Hg was three times higher in bile than in plasma, consistent with the substantial fecal excretion observed. The sheep may be a useful animal model for studying regional deposition of methylmercury in the CNS and mechanisms of methylmercury deposition into hair.
Enhanced intestinal excretion of hexachlorobenzene in rats by intraluminal injection of hexadecane
Authors: Rozman K. , Rozman T. , Greim H. 
Published: October 2006

AbstractThe effect of hexadecane on the intestinal excretion of hexachlorobenzene was studied in female Sprague‐Dawley rats dosed twice with 14C‐hexachlorobenzene at 50 mg kg−1 per os. Injection of 75 mg n‐hexadecane into ligated and unligated segments of the intestine increased concentrations of hexachlorobenzene in intestinal contents by about two‐ or three‐fold in jejunal and ileal segments, and about two‐fold in the cecal—colon segment. The jejunum appeared to be the site of greatest excretion of hexachlorobenzene, followed by the ileum, the cecum and the colon. This order is opposite to our previous data from animals with an undisturbed intestinal passage. The apparently greater excretion of hexachlorobenzene into the small intestine is probably due to its much larger surface area than that of the large intestine. However, the residency time of luminal contents in the large intestine normally exceeds that in the small intestine by about 20–40‐fold, which apparently more than compensates for the difference in relative surface area between small and large intestine. Thus, residency time appears to be a more important factor than surface area in determining the intestinal elimination of hexachlorobenzene. These results with hexachlorobenzene are probably typical of physiological disposition of lipophilic halogenated hydrocarbons generally.
Review of the health effects of methylmercury
Authors: Inskip M. J. , Piotrowski J. K. 
Published: October 2006

AbstractThe study critically reviews recent data relating to the health effects of methylmercury in man and the attendant dose‐response relationships. New data obtained from animal studies, including pre‐ and postnatal exposure, are also examined. The consumption of fish and fish produce represents the major source of methylmercury exposure in the general population. Reported mercury concentrations in fish throughout the world are examined, particularly in the Mediterranean Sea. Here there is limited knowledge of methylmercury intake in critically exposed populations such as fishermen, employees of the fish industries and their families. The measurement of mercury in hair is now regarded as the most useful indicator of exposure but more experimental data are still required to increase the value of this index. The threshold levels of methylmercury in blood, hair and for dietary intake, as estimated by the World Health Organization, have been largely endorsed. However, new information from Japan and Canada suggests the existence of a latency period for some effects, so that the frequency or probability of their occurrence is inversely related to the duration of exposure. Incorporation of such findings would therefore lead to the designation of lower threshold values than are presently recognized. Pregnant women and the fetus have been identified as groups that are at special risk. The fetal blood mercury level is up to twice that of the mother and the sensitivity of both mother and fetus may be higher than in non‐pregnant adults. This should be taken into account when assigning protective threshold concentrations.
Subchronic toxicology of butyl nitrites in mice by inhalation
Authors: McFadden David P. , Maickel Roger P. 
Published: October 2006

AbstractMice were exposed by inhalation to n‐butyl, iso‐butyl sec‐butyl or tert‐butyl nitrite in a dynamic airflow chamber 7 h per day for 60 days at concentrations that caused less than 20% fatalities. Under these conditions, body‐weight gain was depressed over the first 30 days by all four compounds, but returned to normal over the final 30 days for all compounds except tert‐butyl nitrite. Spleen weights were increased by all four butyl nitrites, and lung weights were increased by all except sec‐butyl nitrite. Kidney weights were increased by iso‐butyl and sec‐butyl nitrites, but decreased by the tert‐butyl compound. Liver weights were increased by iso‐butyl nitrite exposure and decreased by tert‐butyl nitrite exposure. The results are consistent with the hypothesis that a significant aspect of butyl nitrite toxicity is due to the resultant methemoglobinemia.
Alveolar permeability to protein in rats differentially susceptible to ozone
Authors: Costa D. L. , Schafrank S. N. , Wehner R. W. , Jellett E. 
Published: October 2006

AbstractSprague‐Dawley rats susceptible (DS) to NaCl‐induced hypertension suffer higher mortality when exposed daily to 2.0 ppm ozone than do hypertension‐resistant (DR) rats, independent of salt in the diet or systemic blood pressure. To investigate one possible contribution to this differential sensitivity to ozone, alveolar permeabilities to serum albumin were measured both in ozone‐exposed and in control DS and DR rats. Female rats aged 5–7 weeks maintained on a low‐salt (0.4% NaCl) diet were injected intravenously with 125I‐bovine serum albumin and were then exposed to either 2.0 ppm ozone or air for 5 h. After pentobarbital anesthesia, the rats were exsanguinated and their lungs were lavaged in situ with saline. Lavage fluids and blood samples were measured for radioactivity using a Nal‐well gamma counter. The results indicated that while DS and DR control rats have similar pulmonary permeabilities to 125I‐albumin, the lungs of the ozone‐exposed DS animals were 63% (p<0.02) more permeable than those of DR rats exposed to ozone. Sloughing of epithelial tissue, mucous formation and an accumulation of macrophages in the end‐airways were more pronounced among ozone‐exposed DS animals than in DR‐ozone‐exposed rats. This increased damage among DS rats correlated well with the increased protein permeability levels. In similar studies, Sprague‐Dawley (D) rats were more variable in their response to ozone than either inbred strain. However, the results appeared generally more like those of the DS animals, suggesting that the trait selected by inbreeding may have been resistance rather than sensitivity to ozone‐induced lung injury.
The efficacy of three non‐mammalian test systems in the identification of chemical teratogens
Authors: Sabourin T. D. , Faulk R. T. , Goss L. B. 
Published: October 2006

AbstractThis report concerns an evaluation of three in vitro teratogenesis tests: the Dugesia regeneration assay, the Hydra reaggregation assay and the Xenopus embryo assay. Our approach involves the establishment and/or refinement of test protocols, definition of endpoints, and evaluation of test performance by comparison with available results of in vivo mammalian studies. Chemicals used for preliminary evaluation studies were the known mammalian teratogens, vinblastine sulfate (VIN) and hydroxyurea (HU), a coeffective teratogen, cadmium chloride (Cd), and an National Toxicology Program priority chemical, 9‐aminoacridine hydrochloride (9AA). The Dugesia assay takes advantage of the ability of beheaded flatworms to regenerate and can be completed in 7–14 days. Concentrations of VIN of 3.2 mg 1−1 inhibited auricle formation and further regeneration observed in 3–6 days. Similarly, eyespot and auricle formation was blocked by HU (180 mg 1−1). The duration of regeneration, measured as the time elapsed between decapitation and eyespot formation (control =5 days), was extended by 1–4 days during exposure to 9AA. Sublethal Cd had little effect on regeneration. The Hydra assay is an evaluation of the ability of dissociated cells to regenerate complete organisms when randomly reassociated. A teratogenic test substance is detected by observing the ratio of the minimal effective concentrations of a substance between intact organisms and regenerates. Compounds with a ratio > 2.0 are potential teratogens. The ratios determined for 9AA, VIN, HU and Cd, respectively, were 10.0, 4.0, 2.7 and 1.2. These results indicate that the first three compounds tested positive for teratogenesis. The Xenopus assay has several endpoints, all of which can be compared with embryolethality in order to index teratogenic hazard. A 4‐day test encompasses development from the blastula stage, through hatching, to formation of swimming tadpoles. Reduced growth was noted during exposure to HU concentrations above 50 mg 1−1 (embryolethality of HU was above 200 mg1−1). Significant skeletal abnormalities, recorded as moderate to severe spinal curvature and resultant loss of swimming ability, were observed during exposure to all four test chemicals. However, this phenomenon was apparent at non‐embryolethal concentrations only for HU and VIN. Further abnormalities, such as altered skin pigmentation and osmoregulatory failure were also recorded.
Development of aquarium fish models for environmental carcinogenesis: An intermittentflow exposure system for volatile, hydrophobic chemicals
Authors: Walker William W. , Manning C. Steve , Overstreet Robin M. , Hawkins William E. 
Published: October 2006

AbstractAn intermittent‐flow exposure system was designed to provide stable and manipulative concentrations of volatile and hydrophobic compounds to small aquatic animals for uninterrupted long periods. Test species for 28‐day experiments included two aquarium fishes, the Japanese medaka (Oryzias latipes) and the king cobra guppy (Poecilia reticulata). Test chemicals included trichloroethylene, vinylidene chloride, bis (2‐chloroethyl)ether, ethylene dichloride, and a mixture of carbon tetrachloride, trichloroethylene, chloroform, bromodichloromethane, chlorodibromomethane and bromoform. These compounds are drinking water biorefractories and are potentially carcinogenic. Concentrated aqueous toxicant solutions, delivered from a remote triple carboy dispensing system, were mixed with diluent water within an isolated chamber containing exposure aquaria and test fish. Toxicant concentrations measured throughout each exposure period proved to be stable within acceptable variability ranges as indicated by coefficients of variation generally less than 15%.
Development of aquarium fish models for environmental carcinogenesis: Tumor induction in seven species
Authors: Hawkins William E. , Overstreet Robin M. , Fournie John W. , Walker William W. 
Published: October 2006

AbstractFor small fish species to be utilized as models for carcinogenicity testing they should be capable of developing neoplasms, preferably in multiple tissues, when exposed to known carcinogens. Seven species of small fish were exposed to methylazoxymethanol acetate (MAM‐Ac) and tumor development was monitored. Specimens 6–10 days old were exposed to nominal concentrations of MAM‐Ac up to 100 mg l−1 for 2 h, then transferred to carcinogen‐free water. Hepatic neoplasms developed in the Japanese medaka, guppy, sheepshead minnow, Gulf killifish, inland silverside, rivulus, and fathead minnow. Additionally, neoplasms occurred in other organs and tissues of the medaka (retina, various mesenchymal tissues, exocrine pancreas, kidney, and nervous tissue), guppy (mesenchymal tissue, exocrine pancreas, and kidney), and sheepshead minnow (choroid gland, mesenchymal tissues, and nervous tissue). All tumors were diagnosed in specimens within 1 year post‐exposure. Early signs of liver tumors appeared in medaka and guppy at about 1 month post‐exposure. These studies show that both medaka and guppy would be good models because they appear sensitive to carcinogens, develop tumors in multiple tissues and are easy to breed and maintain. Certain other small fish species also may prove to be good models because of habitat preferences, breeding strategies, or genetic attributes.