bluuebunny/crossref_metadata_2025_split huggingface dataset:
Normal organic and inorganic mercury levels in the human feto‐placental system
Authors: Suzuki Tsuguyoshi , Yonemoto Junzo , Satoh Hiroshi , Naganuma Akira , Imura Nobumasa , Kigawa Tomonori 
Published: October 2006

AbstractTo clarify the normal metabolism of mercurials in the human feto‐placental system, organic (or methyl) mercury and inorganic mercury were measured in maternal blood (MB), umbilical cord blood (UB), and chorionic tissues of the placenta (PC) and its blood vessels (PV), obtained from pregnant women just after delivery, as well as in fetal liver and fetal brain from induced abortion cases. Organic mercury was commonly detected in MB, UB, PC and PV, with slightly more elevated values in UB and PC than in MB, whereas inorganic mercury was detected in PC and PV, but not in MB and UB. In the fetal liver, 27–60% of mercury was in the form of inorganic mercury, whilst in four of five fetal brain samples, inorganic mercury was not detected. Additionally, fetal liver demethylation activity was studied in vitro. Incubation of methyl mercury with chopped fetal liver tissue for 24 h resulted in demethylation of approximately 1% of the methyl mercury.
A comparison of two methods of bleeding rats: The venous plexus of the eye versus the vena sublingualis
Authors: Angelov O. , Schroer R. A. , Heft S. , James V. C. , Noble J. 
Published: October 2006

AbstractOf paramount importance to most toxicological studies in rats is the evaluation of hematological and clinical chemistry parameters. Currently, the principle bleeding method utilizes the venous plexus of the eye. This procedure has no detrimental effect on the general health of the animal and yields a sufficient quantity of blood, but has the potential disadvantage of damaging the eye. To avoid this disadvantage, a method was developed which is simple to perform, yields a sufficient quantity of blood and leaves the eye unimpaired. Samples are taken from the vena sublingualis. In order to compare the two methods, a study was initiated to determine the effect on body weight and food consumption as well as to compare hematological and serum chemistry parameters. The results showed that drawing blood from the vena sublingualis did not affect body weight or food consumption, and no significant differences were found in the hematological or serum chemistry values obtained by either method.
Administration of activated charcoal for the treatment of lantana poisoning of sheep and cattle
Authors: Pass Michael A. , Stewart Coralie 
Published: October 2006

AbstractThe use of activated charcoal for treating lantana poisoning was investigated. When 500 g of activated charcoal was given orally with toxic Lantana camara, it protected sheep against intoxication. Administration to sheep of 500 g of activated charcoal in 4 1 of electrolyte solution orally 6 days after the onset of lantana poisoning and then 4 1 of electrolyte solution the next day, was followed by recovery from the intoxication. Mortality was significantly higher in intoxicated sheep given only the electrolyte solution and in untreated sheep. Six cows with naturally occurring lantana poisoning were treated with 2–2.5 kg of charcoal in 20–30 1 of electrolyte solution given by stomach tube and all the animals recovered. It is recommended that sheep with lantana poisoning be treated orally with 500 g of activated charcoal in 4 1 of electrolyte solution, and that cattle be given 2 kg of charcoal in 20 1 of electrolyte solution. Supportive treatment for photosensitization and dehydration may also be required.
Vitamin E improves membrane lipid alterations induced by CCl4 intoxication
Authors: Martínez‐Calva I. , Campos‐Apáez A. , Rosales‐Vega E. , Mourellet Marisabel 
Published: October 2006

AbstractThe effect of pretreatment with vitamin E on membrane lipid alterations produced by the acute intoxication with CCl4 was studied. Rats were treated with an oral dose of CCl4 (0.4 g per 100 g body weight) and 24 h later the animals were sacrificed and liver plasma membranes isolated. After extraction, the membrane lipids were analysed by thin‐layer chromatography and quantitated by densitometry. The phospholipid: protein ratio determined in plasma membranes of CCl4‐treated rats was almost three‐fold higher than that found in control animals. Sphingomyelin (Sph) and phospharidyl choline (PC) increased, while phosphatidyl ethanolamine (PE) decreased in the plasma membranes isolated from the CCl4–treated group. Animals pretreated for 7 days with a daily dose of vitamin E (200 IU per kg body weight) showed a lower increase in the phospholipid: protein ratio (two‐fold) and the changes in Sph, PC and PE were lower. When the rats were pretreated with a higher dose of vitamin E (400 IU per kg body weight) for the same period, the lipid composition of plasma membrane was normal. These results indicate that vitamin E can protect against the alterations induced by CCl4 on the liver membranes. The protective action of vitamin E against CCl4 membrane damage is probably associated with its antioxidant properties.
The occurrence, metabolism and toxicity of cinnamic acid and related compounds
Authors: Hoskins John A. 
Published: October 2006

AbstractCinnamic acid is a compound of low toxicity, but its molecular structure and the known toxicity of similar molecules, such as styrene, have brought it to the toxicologist's attention. Commercially, its use is permitted as flavouring and it is ubiquitous in products containing cinnamon oil and to a lesser extent in all plants. The related aldehyde, alcohol and esters are all more toxic than cinnamic acid. Certain substituted cinnamates containing cyano and fluoro moieties are of particular interest because they inhibit mitochondrial pyruvate transport. The literature about this whole group of commercially important compounds is diverse and many key studies are in languages other than English. This review looks at the history and legal constraints, as well as the results of metabolism and toxicology studies.
Kidney toxicity of 3‐methylxanthine in the rat
Authors: Sellman R. , Klemi P. J. 
Published: October 2006

AbstractThe effects of 3‐methylxanthine, the pharmacologically active metabolite of theophylline, on the kidneys of Wistar rats after short‐term administration were studied. 3‐Methylxanthine was administered in oral doses of 0 (control), 50, 100 and 200 mg per kg per day for 1, 8 and 16 days. The kidneys were examined by light and electron microscopy. Tubular necrosis was noticed at a dose level of 100 mg kg−1 after 16 days and at a dose level of 200 mg kg−1 after 8 days. Elevated values of serum urea were found after 1 day of treatment with a dose of 200 mg kg−1 and after 16 days with a dose of 100 mg kg−1. Elevated values of serum creatinine were detected after 8 days of treatment with a dose of 200 mg kg−1. The results indicate dose‐ and time‐related renal failure following administration of 3‐methylxanthine.
Thallium replaces potassium in activation of the (Na+, K+)‐atpase of rat liver plasma membranes
Authors: Favari Liliana , Mourelle Marisabel 
Published: October 2006

AbstractThe capacity of thallium to substitute for K+ in activation of (Na+, K+)‐ATPase of liver plasma membranes was studied. Our results indicate that Tl+ can replace K+ in the activation of the (Na+, K+)‐ATPase of liver plasma membranes. In the presence of Na+, similar activation is obtained with Tl+ concentrations only 1/10 of those of K+. In all other aspects, the (Na+, K+)‐ and (Na+, Tl+)‐ATPases were found to be identical.
Hexachloro‐1, 3‐butadiene‐induced hydropic change in mouse liver
Authors: Lock Edward A. , Pratt Iona S. , Ishmael John 
Published: October 2006

AbstractHexachloro‐1, 3‐butadiene (HCBD) produced a time‐ and dose‐related increase in hepatic water content following i.p. administration to male Alderley Park (Alpk/AP) mice. The increase in liver water was maximal 1–2 days after a single dose of 50 mg kg−1 and had returned to normal by day 5. Associated with the increased water, there was a parallel increase in Na+ and K+ ions, with no overall change in intracellular cation concentration. Liver non‐protein sulphydryl content showed no consistent time‐related decrease after 50 mg kg−1 HCBD. Histopathological examination of the liver showed fine cytoplasmic vacuolation of periportal hepatocytes which was more marked following 100 or 200 mg kg−1 than 50 mg kg−1 HCBD. In one animal, following 200 mg kg−1 HCBD, the liver showed ballooning and degeneration of periportal hepatocytes. Ultrastructural changes were evident 4 h after 50 mg kg−1 and consisted of mitochondrial swelling in periportal hepatocytes, whilst pericentral hepatocytes appeared normal. By 16 h, marked mitochondrial swelling and some proliferation of smooth endoplasmic reticulum were evident in periportal hepatocytes. Male mice of the C57BL/10J and C3H strains appeared to be more sensitive to HCBD‐induced hepatic hydropic change than did the male and female Alpk/AP strain and male Balbc and DBA/2 J strains. It appears that HCBD or a metabolite causes disruption of mitochondria in periportal hepatocytes which results in an influx of water and ions into the cell without compromising the Na+ pump.
Comparative chemical and biological analysis of coal tar‐based therapeutic agents to other coal‐derived materials
Authors: Wright Cherylyn W. , Later Douglas W. , Pelroy Richard A. , Mahlum D. Dennis , Wilson Bary W. 
Published: October 2006

AbstractIn this study, methodologies developed for the analysis of synthetic fuel products were applied to the coal tar fractions isolated from coal tar‐based pharmaceutical products. A pharmaceutical stock solution of 20% coal tar in alcohol, a 50% coal tar bath emulsion and a 4.3% coal tar shampoo were studied. The toxicology and chemical composition of the coal tar fractions isolated from these materials were compared with an industrial coal tar and with a direct‐liquefaction coal liquid product. The coal tars and coal liquid product were fractionated into chemical classes by alumina column chromatography and individual components were identified and quantitated by high‐resolution gas chromatography. The microbial mutagenicity of these materials was measured against S. typhimurium, TA 98. In addition, the industrial coal tar, coal‐liquid product, and coal tar isolate from the 20% coal tar in alcohol solution were tested for initiating activity in an initiation/promotion mouse skin painting assay for carcinogenicity. The chemical compositions of the coal tar‐based therapeutic agents, the industrial coal tar and direct‐liquefaction coal liquid were similar. With the exception of the 50% bath emulsion, the microbial mutagenicity and tumor‐initiating activity in mouse skin for those materials tested were also similar.
Effects of alcide® gel on fetal development in rats and mice. II
Authors: Gerges Samy E. , Abdel‐Rahman Mohamed S. , Skowronski Gloria A. , Hagen Stanley Von 
Published: October 2006

AbstractAlcide® gel is a germicidal agent which is highly effective in killing a wide range of bacterla and fungi in vitro within 1 min. Alcide® gel consists of sodium chlorite and lactic acid, parts A and B, respectively. Chlorine dioxide is formed when sodium chlorite and lactic acid, the active ingredients of Alcide®, are mixed. The objective of this investigation was to study the teratogenic effects of Alcide® gel both in rats and in mice. The gel was administered topically in doses of 1 and 2 g per kg body weight on days 6–15 of gestation. No toxic symptoms were observed following exposure of pregnant rats and mice to Alcide® gel. Viability of the fetuses as well as weight, length and number of resorptions were quite similar compared with control groups. Fetuses were examined for external, visceral and skeletal anomalies. Some incidence of missing or incompletely ossified sternebrae, missing ribs and incomplete ossification of skull bones were observed from skeletal examination. Gastromegaly, kidney agenesis, heart displacement, interatrial septal defect, limb hyperflexion and club foot were observed from soft‐tissue examination. These defects, however, were not significantly different compared with control animals. Alcide® gel was not teratogenic at the doses tested.
Comparative cytotoxicity of naphthalene and its monomethyl‐ and mononitro‐derivatives in the mouse lung
Authors: Rasmussen Ronald E. , Do Diem Hoang , Kim Tae Sun , Dearden Lyle C. 
Published: October 2006

AbstractMale Swiss‐Webster mice were exposed to napthalene, 1‐methyl‐, 2‐methyl‐, 1‐nitro‐ and 2‐nitronaphthalene by intraperitoneal injection of peanut oil solutions over a dose range of 0.5–3.0 mmol kg−1 body weight. Treated mice were killed at times from 6 hours to 14 days post‐treatment. Tissues were analyzed for cytotoxic effects by optical and electron microscopy, and for cell proliferation by autoradiography following in vitro labeling of lung slices with 3H‐thymidine. The naphthalene derivatives varied widely in their cytotoxic effects. The most toxic was 1‐nitronaphthalene with no mice surviving doses greater than 1 mmol kg−1. Naphthalene and 2‐methylnaphthalene were about equally toxic, followed by 2‐nitro‐ and 1‐methylnaphthalene, in decresing order of toxicity. In all cases the first evidence of cytotoxic effects was seen in the Clara cells of the bronchiolar epithelium, and at the highest doses, toxic effects were found in the adjacent ciliated cells. Changes could be detected at the ultrastructural level at all doses, and within 6 hours after treatment. Only slight effects were seen in other cell types. Increased cell proliferation following chemical treatment was seen only in the bronchiolar epithelium, among cells tentatively identified as Clara cells or their precursors. Cytotoxic effects of naphthalene and its 1‐ and 2‐methyl derivatives were confined to the lung, with minimal evidence of toxicity in the liver and kidney. The mononitronaphthalenes both produce small areas of centrizonal necrosis in the liver, but no discernible effects in the kidney. The experiments demonstrate the effect of small structural differences on the cytotoxicity of this group of environmental pollutants and also illustrate the sensitivity of the Clara cell as a target for xenobiotics.
The relative induction of mixed‐function oxidase specific activity to CH and CC1 bond strengths in polychlorinated derivatives of dibenzo‐p‐dioxin (PCDDs)
Authors: Brownlee L. J. , Evans C. H. , Hollebone B. R. 
Published: October 2006

AbstractThe structure–activity relationships between the mixed‐function oxidase (MFO) system and six polychlorinated derivatives of dibenzo‐p‐dioxin (PCDDs) were studied using Sprague Dawley rats. The study was set up in accordance with previous work in these laboratories involving monocyclic hydrocarbons. Three possible mechanisms at the MFO active site are proposed. C—H bond hydroxylation in low chlorine substituted PCDDs, and probable exposidation in the intermediate chlorinated species including 2378 tetrachlorodibenzodioxin. Benzo[a]pyrene activity induced by some PCDDs appears irrelevant to the desired metabolic result.
Alterations in prostacyclin and thromboxane formation by chronic cigarette smoke exposure: Temporal relationships and whole smoke vs. gas phase
Authors: Lubawy W. C. , Culpepper B. T. , Valentovic M. A. 
Published: October 2006

AbstractChronic cigarette smoke exposure in vivo causes decreased conversion of [14C]arachidonic acid (AA) to prostacyclin (PGI2) by isolated aortic tissue and increased conversion to thromboxane (TXA2) by isolated platelets from rats. Alterations in the PGI2/TXA2 balance may be part of the mechanism through which smoking increases the risk of cardiovascular disease. To study the influence of smoke exposure duration on this response, male rats were exposed daily to 10 puffs of freshly generated cigarette smoke. Animals were klledd after 1, 4, 14, 28 and 57 days of smoke exposure and 3, 7, 14 and 28 days after cessation of the 57‐day of smoke‐exposure regimen. Elevated carboxyhemoglobin levels during the smoke‐exposure sessions verified smoke (gas phase) inhalation. Statistically significant alterations in prostacyclin synthesis preceded those of thromboxane. A decrease of 20‐25% (P<0.05) in PGI2 production from [14C]AA in isolated aortic tissue was found beginning 28 days after smoke was initiated and quickly rebounded when smoke exposure was terminated. Increased production of TXA2 from [14C]AA by isolated platelets became statistically significant (P<0.05) on the 57th day and returned to normal 7–14 days after cessation of smoke exposure.To determine the effect of gas phase constituents on the PGI2/TXA2 balance a second series of experiments divided male and female Sprague‐Dawley rats into sham, whole smoke and gas phase groups. Gas phase was produced by passing whole smoke through a Cambridge filter to remove particulate matter. Per cent COHb averaged 1.4 for sham, 7.8 for whole smoke and 9.4 for gas phase groups. After 8 and 12 weeks of exposure, whole smoke decreased aortic PGI2 and increased platelet TXA2 both in male and in female rats. In contrast to whole smoke exposure, 8 or 12 weeks of exposure to gas phase constituents filed to produce any statistically significant alteration in PGI2 and TXA2 formation.It was concluded that changes in PGI2 and TXA2 formation occur readily following initiation or termination of chronic whole smoke exposure and that substances present in the particulate phase of smoke are essential to producing these changes.
The effects of chronic ozone exposure on pulmonary collagen content and collagen synthesis in rats
Authors: Filipoicz C. , McCauley R. 
Published: October 2006

AbstractMale rats were exposed to 0.125, 0.25 or 0.5 ppm of ozone or clean air for up to 1 year. During this exposure period there was little evidence for collagen accumulation in the lungs. However, the rate of incorporation of tritriated proline into both lung collagen and total lung protein was accelerated. These data suggest that exposure to ozone under these conditions results in an increase in the turnover of collagen as well as other lung proteins.
Effect of donor age on the levels of activity of rat, hamster and human liver S9 preparations in the Salmonella mutagenicity assay
Authors: Raineri R. , Andrews A. W. , Poiley J. A. 
Published: October 2006

AbstractLiver S9 fractions were prepared from male and female Syrian Golden hamsters and Sprague‐Dawley rats, 1, 3, 6 and 12 months of age, which were either iuninduced (corn‐oil treated) or induced with Aroclor 1254 suspended in corn oil. These preparations were compared at varying protein levels for their ability to metabolize polycyclic aromatic hydrocarbons (benzo(a)pyrene, 3‐methylcholanthrene, 7,12‐dimethylbenzanthracene), aromatic amines (N‐2‐acetyl‐aminofluorene, β‐naphthylamine, benzidine), and nitroso compounds (N‐nitroso‐diethylamine, nitrosopyrrolidine, nitrosodiethylmethylurea) to products mutagenic to Salmonella typhimurium. With 3‐methylcholanthrene or benzo(a)pyrene in the presence of S9 preparations from Aroclor‐treated male rats, the numbers of revertant colonies decreased with increasing age of the animals. Mutagenicity of aromatic amines was not affected by the age of the donor animals from which the S9 was prepared. The use of liver S9 from 1‐month‐old hamsters produced the highest number of revertant colonies with nitrosodiethylamine. This number decreased with preparations from animals of increasing age. The greatest number of revertant colonies with nitrosopyrolidine occurred with preparations from male hamsters. A decrease in numbers of revertant colonies with increasing age was observed with the S9 preparation from Arcolor‐treated male rats. Nitroso‐diethylmethylurea was mutagenic only in the presence of S9 from male or female Aroclor‐treated hamsters and the metabolic activity of the S9 preparations did not change with age.S9 preparations from livers of 50–70‐year‐old humans were compared for their ability to produce mutagenic metabolites at a number of protein levels. Very low levels of mutagenicity with polycyclic aromatic hydrocarbons were seen with all human liver S9. Two preparations from human liver obtained shortly after death metabolized both benzidine and β‐naphthylamine (known human carcinogens) to mutagenic products. Very low or no increases in the number of revertant colonies were seen with the other human S9s. However, all of these liver S9 preparations gave a positive mutagenic response with N‐2‐acetylaminofluorene. The only nitrosamine mutagenic with human liver S9 was nitrosopyrrolidine. All of the human preparations metabolized this carcinogen at similar levels.To obtain a positive mutagenic response with a number of these compounds, it was important that the tissue samples be obtained with minimum delay after death. The ability of S9 preparations made from tissues of older rats to metabolize chemicals to mutagenic products was diminished, and compared well with the results obtained with S9s from 50–70‐year‐old humans. These findings demonstrate the value of the Salmonella mutagenicity assay used with liver S9 preparations from humans in screening for potentially harmful agents.
Measurement of the deposition and clearance of inhaled radiolabeled particles from rat lungs
Authors: Newton Paul E. , Pfledderer Chris 
Published: October 2006

AbstractImmediately after a 20 min nose only exposure to 51Cr labeled polystyrene latex microspheres (1.4 MMAD, geometric standard deviation = 1.3, 2 μg m−3), 23% of the measured radioactivity was within the trachealungs of the exposed rats, 37% was within the gastrointestinal tract, 10% was within the defurred head, and 30% was on the fur. One hour after deposition these percentages had changed to 20, 64, 5 and 11% respectively. As a result of this non‐pulmonary particle load transiting the esophagus, external thoracic radioactivity measurements did not accurately reflect excised lung measurements until 30 h post‐deposition. Consequently, it was necessary to combine excised lung ratioactivity data (0–30 h post deposition) with serial external thoracic measurements (30–934 h post‐deposition) to measure the clearance of these microspheres. Use of an annulus shaped detector sufficiently increased sensitivity to allow measurements to be made through at least 934 h post‐deposition. The lung radioactivity retention curve was biexponential with half times of 34.3 ± 2.3 and 963 ± 107 h. Simultaneous exposures to 5% CO2 increased deposition by 40% but failed to reduce deposition inhomogeneity and test variability.
Mercury–selenium interaction in workers exposed to elemental mercury vapor
Authors: Suzuki Tsuguyoshi , Himeno Sei‐Ichiro , Hongo Tetsuro , Watanabe Chiho , Satoh Hirosi 
Published: October 2006

AbstractMercury (Hg) and selenium (Se) levels were determined for erythrocytes, plasma and urine of 25 male and 29 female workers exposed to elemental mercury (Hg0) vapor. Interrelationship between the Hg levels and the Se levels was examined by the correlational analysis and the stepwise regression analysis.Indicators of Se status (erthrocyte Se levels, plasma Se levels and urinary Se levels) were closely inter‐correlated; similary, indicators of exposure to Hg0 vapor (erythrocyte inorganic Hg levels, plasma Hg levels and urinary Hg levels) were significantly intercorrelated. Since plasma Hg level was one of the significant independent variables in determining the erythrocyte Se and plasma Se levels, Hg0 vapor exposure was though likely to influence the Se metabolism in workers. None of the Se status indicators were significant as determinants of the indicators of Hg0 vapor exposure.