bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of palytoxin on endothelium‐dependent and ‐independent relaxation in rat aortic rings
Authors: Taylor Thomas J. , Smith Neil C. , Langford Michael J. , Parker Gerald W. 
Published: October 2006

AbstractEndothelium‐intact rat aortic rings were incubated with palytoxin (PTX, 10−11–10−9M, 10 min) in oxygenated (O2 95%, CO2 5%) baths. Phenylephrine (PE)‐contracted vascular rings demonstrated decreasing relaxation to acetylcholine (ACh), depending upon PTX incubation in a dose‐dependent manner; however, sodium nitroprusside (NaNP) persisted in returning the ring to its pre‐PE tension. After incubation with PTX, relaxation to the receptor‐independent, endothelium‐dependent relaxant A23187 was also attenuated. Thus, endothelium‐dependent mechanism(s) normally responsive to both ACh and A23187, stimulators of nitric oxide (NO) release, were disrupted. Following incubation with PTX, endothelium‐independent relaxation to NaNP remained intact but relaxation to atriopeptin II (APII) decreased. Electron microscopy demonstrated microvesiculation of endothelial cell cytoplasm and an irregular luminal surface following incubation with PTX. The intact response to NaNP, despite the loss of relaxation to ACh, indicated that soluble guanylate cyclase was not affected by PTX. However, loss of relaxation to AP‐II, involving particulate guanylate cyclase of vascular smooth muscle (VSM), was inhibited by PTX pre‐incubation. Determination of the site(s) of action of PTX requires further study.
Use of a head dome system to compare i.v. methacholine‐induced bronchoconstriction in conscious vs anesthetized rhesus monkeys
Authors: Allen D. L. , Pollard K. R. , Hughes B. L. , Dorato M. A. , Wolff R. K. 
Published: October 2006

AbstractThe use of a newly developed head dome system has allowed measurement of pulmonary function in conscious monkeys. Such information is often desired, so that pharmacological or toxicological effects of administered compounds can be measured in the absence of effects from anesthetic agents. The current study was conducted to gain experience with this method and to allow the determination of the effects of sodium pentobarbital anesthesia (30 mg kg−1 i.v.) on the bronchoconstriction seen during i.v. infusion of methacholine in rhesus monkeys. Bronchoconstriction was measured as changes in respiratory resistance using a Buxco LS20 pulmonary mechanics computer. Four male rhesus monkeys (4.2–5.1 kg) were used. For the anesthetized exposures, the animals were intubated with a 4.0‐mm cuffed endotracheal tube attached to a size ‘O’ Fleisch pneumotachograph. For the conscious exposures, the animals sat in restraining chairs with a custom‐built head dome attached to the same pneumotachograph. In both cases, transthoracic pressure was monitored with an intrapleural catheter. Each monkey was infused with methacholine in stepwise doses, while anesthetized and conscious, until a 75% increase in respiratory resistance was seen. The ed50 values of 0.134 and 0.180 mg ml−1 methacholine were not significantly different in anesthetized vs conscious monkeys, respectively.
Red blood cell damage by wollastonite: in vitro study
Authors: Aslam M. , Arif M. J. , Rahman Q. 
Published: October 2006

AbstractAsbestos is known to cause lung diseases in occupationally exposed workers. These properties have restricted its use. Industries have been exploring the possibility of other mineral fibres to replace the asbestos. In this direction, wollastonite has gained great attention owing to its high thermal resistance. In the present paper, the toxicity of three samples of Indian wollastonite was compared to that of chrysotile. Dust suspensions were added to the red blood cell suspensions to obtain a final dust concentration of 1.0–5.0 mg ml−1 in the system. The wollastonite varieties were found to have smaller haemolytic potential in human red blood cells than that of chrysotile in vitro. Chrysotile also was more effective in inducting peroxidative damage of polyunsaturated fatty acid (PUFA) than wollastonites in the present system. The peroxidative damage of PUFA and the haemolysis were both time and dose dependent. A higher value of malonaldehyde (a lipid peroxidation product) formation in low‐speed supernatant of haemolysate was observed than in the intact cells. As the free‐radical scavengers vitamin E and reduced glutathione prevent haemolysis and lipid peroxidation, these data are consistent with the involvement of lipid peroxidation in the haemolytic process.
Role of cellulose in wood dust‐induced fibrosing alveo‐bronchiolitis in rat
Authors: Tátrai Frzsébet , Adamis Zoltán , Böhm Ute , Merétey Katalin , Ungváry György 
Published: October 2006

AbstractOur experiments suggest that in the development of plant dust‐induced fibrosing alveobronchiolitis—Scadding's fibrosing alveolitis—the cellulose content of plant dusts has a decisive aetiological role. Namely, the wood dust (pine) and the cellulose induced morphologically identical granulomatous inflammation and fibrosis, whereas the fibre‐free extract of wood dust did not cause pathological changes in the lungs. The induction of H2O2 and superoxide anion production, shown in vitro in leucocytes, probably has an important role in the development of fibrosis.
Relationship between oxygen‐induced alveolar macrophage injury and cell antioxidant defence
Authors: Aerts Colette , Wallaert Benoit , Gosset Philippe , Voisin Cyr 
Published: October 2006

AbstractExposure to hyperoxia causes alveolar macrophage (AM) injury. The present study investigates the roles of intracellular antioxidant enzymes and of glutathione in the protection of AMs against hyperoxia in a biphasic cell culture system in aerobiosis. The effect of normoxia or hyperoxia on the integrity of AMs was related to indices of cell injury (ATP cell content and lactate dehydrogenase release into culture medium) and cell mass (protein content of AMs). Antioxidant activities were measured in guinea‐pig AMs exposed to 95% O2 or to normoxia (control cells) for 3 days. A 3‐day AM culture in normoxia showed a significant decrease in protein and catalase, whereas ATP cell content, superoxide dismutase (SOD) (both Cu, Zn‐SOD and Mn‐SOD) and glutathione peroxidase (GPx) activities significantly increased. The content of reduced glutathione (GSH) did not change. Using the ATP content in AMs expressed as a cell injury index (CII), AM injury increased with increasing O2 exposure time (1 day: 13 ± 4.4%; 2 days: 34 ± 3.8%; 3 days: 40 ± 4.1%; 4 days: 55 ± 7.3%; 6 days: 87.5 ± 5.4%). Exposure to 95% O2 for 3 days was associated with a significant decrease in ATP cell content, protein, catalase and GSH to the total glutathione ratio, whereas SOD, GSH and total glutathione did not change significantly. The GPx activities increased significantly. There was no significant correlation between the AM CII and SOD or GPx content. In contrast, a significant correlation was observed between hyperoxia‐induced AM CII and catalase content (r = 0.71) and glutathione content (r = 0.71). Incubation of AMs with buthionine sulphoximine, a specific inhibitor of glutathione synthesis, significantly decreased the GSH content, whereas the ATP content and antioxidant enzyme activities in the AMs did not change. Reduction of intracellular GSH increased hyperoxia (50% O2)‐induced AM injury from 2.2 ± 6% to 53 ± 10.2%. Our results support the concept that regulation of cell GSH is an important mechanism of protection against hyperoxic injury.
Long‐term effects of a cross‐linked polyacrylate superabsorbent in the hamster
Authors: McGrath James J. , Purkiss Laquetta , Eberle Mary , McGrath W. R. 
Published: October 2006

AbstractMale and female Syrian Golden hamsters breathed respirable (<10 μm) cross‐linked polyacrylate dust (0.3, 1.0 or 10 mg m−3) for 6 h a day, 5 days per week for 28 exposures and were then held for 42 and 46 weeks. The animals appeared healthy during and immediately following the exposure; there were no differences in body weight at any dose, nor were there any deaths.Foreign material was detected in the lungs 42 and 46 weeks post‐exposure. There was a slight increase in alveolar macrophages, which appeared to be dose related, and there was a slight increase in inflammatory cells at the highest dose. There was no evidence of fibrosis in any group either 42 or 46 weeks post‐exposure.The first animal (male, control) died 12 weeks post‐exposure and mortality increased from 21 weeks post‐exposure. The deaths were not dose related but were distributed equally across all groups and appeared to be part of the normal mortality patterns for hamsters.These results indicate that repeated exposure of Syrian Golden hamsters to low concentrations of cross‐linked polyacrylate dust in particle sizes capable of reaching deep lung structures does not cause pulmonary fibrosis at a later time in the life‐cycle. When combined with our earlier results, these data indicate that the test material is continuously cleared from the lung following termination of the exposure.
Dose‐response relationship between total cadmium intake and prevalence of renal dysfunction using general linear models
Authors: Hochi Yasushi , Kido Teruhiko , Nogawa Koji , Kito Hideaki , Kito Hideaki , Shaikh Zahir A. 
Published: October 2006

AbstractTo determine the maximum allowable intake limits for chronic dietary exposure to cadmium (Cd), the dose‐response relationship between total Cd intake and prevalence of renal dysfunction was examined using general linear models considering the effect of age as a confounder. The target population comprised 1850 Cd‐exposed and 294 non‐exposed inhabitants of Ishikawa, Japan. They were divided into 96 subgroups by sex, age (four categories) cadmium concentrations in rice (three categories) and length of residence (four categories). As indicators of the cadmium‐induced renal dysfunction, glucose, total protein, amino nitrogen, β2‐microglobulin and metallothionein in urine were employed. General linear models were fitted statistically to the relationship among prevalence of renal dysfunction, sex, age and total Cd intake. Prevalence of abnormal urinary findings other than glucosuria had significant associations with total Cd intake. When total Cd intake corresponding to the mean prevalence of each abnormal urinary finding in the non‐exposed subjects was calculated using general linear models, total Cd intakes corresponding to glucosuria, proteinuria, aminoaciduria (men only) and proteinuria with glucosuria were determined to be ca. 2.2–3.8 g and those corresponding to prevalence of metallothioneinuria were calculated as ca. 1.5–2.6 g. The low‐molecular‐weight protein in urine was confirmed to be a more sensitive indicator of renal dysfunction, and these total Cd intake values were close to those calculated previously by simple regression analysis, suggesting them to be reasonable values as the maximum allowable intake of Cd.
Two‐generation reproduction toxicity study with isopropanol in rats
Authors: Bevan C. , Tyler T. R. , Gardiner T. H. , Kapp R. W. , Andrews L. , Beyer B. K. 
Published: October 2006

AbstractA two‐generation reproduction toxicity study was conducted in rats with isopropanol. Thirty rats of each sex per group (P1) were dosed once daily by oral gavage with 0, 100, 500 or 1000 mg isopropanol kg−1 for at least 10 weeks prior to mating. Parental animals were mated within groups for up to 3 weeks. Parental females were dosed during mating, gestation and lactation; parental males were dosed during mating through delivery of their last litter sired. The P2 adults were selected from the F1 litters and were dosed for 10–13 weeks before mating to produce a single litter. Findings in the parental animals included increased lactation body weight gain in the mid‐ and high‐dose females, increased liver and kidney weights in the mid‐ and high‐dose groups of both sexes and centrilobular hepatocyte hypertrophy in some P2 males. There was also accumulation of hyaline droplets and other microscopic findings in the kidneys from the mid‐ and high‐dose P1 males and from all treated groups of the P2 males. Increased mortality was observed in the high‐dose F1 offspring during the early postnatal period, although no other clinical signs of toxicity were observed in the offspring of either generation. In addition, offspring body weight was reduced during the early postnatal period in the high‐dose F1 males and in the high‐dose F2 pups of both sexes. Eighteen out of 70 F1 weanlings in the 1000 mg kg−1 group died or were euthanized prior to P2 selection. No treatment‐related post‐mortem findings were observed in the offspring from either generation. A statistically significant reduction was observed in the male mating index of the high‐dose P2 males compared with that of the controls. However, no treatment‐related microscopic changes in reproductive tissues or biologically meaningful differences in other reproductive parameters were observed in adults of either generation. The no‐observed‐effect‐level (NOEL) for reproductive effects in this study, based on the reduced male mating index of the high‐dose P2 males, is 500 mg kg−1 day−1.
High fat diet and liver damage induced by biliary obstruction in the rat
Authors: Muriel Pablo 
Published: October 2006

AbstractThere is a great body of evidence linking a high fat diet with the formation of gallstones. However, the effect of fat per se on obstructive liver damage (not involving gallstone formation) has not been assessed. The aim of this work was to study the effect of a high fat diet on liver damage induced by bile duct ligation in rats. Male 21‐day‐old Wistar rats were divided into two groups: group 1 received standard Purina chow diet 5001 containing 4.5% fat, group 2 received Purina chow diet 5001 enriched with 33% pork fat. Animals were allowed food and water ad libitum for 5 weeks. Obstructive jaundice was induced by double ligation and division of the common bile duct. The animals were sacrificed 1 week after biliary obstruction. Control animals were sham operated. Serum bilirubins and alkaline phosphatase, γ‐glutamyl transpeptidase and glutamic pyruvic transaminase enzyme activities increased by biliary obstruction. Glycogen content decreased in the bile duct‐ligated rats. These effects were more important in the group fed a 33% fat diet. Our results show that a high animal fat diet increases liver damage in experimental biliary obstruction in rats. Owing to our experimental design (bile duct ligation), the effect of a high fat diet cannot be attributed to an increase in the formation of gallstones but a direct effect must be considered. The mechanism by which fat augmented liver damage can be associated with an increase of total bile content and its toxicity.
Decrease in hepatotoxicity by lead exposure is not explained by its mitogenic response
Authors: Calabrese Edward J. , Baldwin Linda A. , Leonard Denise A. , Zhao Xiao Qiang 
Published: October 2006

AbstractThe present research was conducted to evaluate the effect of mitogen pre‐exposure on CCl4‐induced hepatotoxicity. Male Wistar rats were administered a single i.p. injection of CCl4 (0.3 ml kg−1 in corn oil) 48 h following either a single dose of lead nitrate (0.33 mg kg−1) or distilled water via i.v. injection. Hepatotoxicity, as measured by serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, was monitored 6, 24, 48, 72 and 120 h after CCl4 exposure. The lead nitrate‐pretreated rats displayed markedly lower serum ALT and AST levels at 24, 48 and 72 h than rats pretreated with distilled water. However, treatment with the antimitotic agent colchicine did not alter the lead‐induced protection. These findings suggest that the lead‐induced protection is not associated with the major mitogenic response of lead, despite its strong temporal association. A critical review of the available toxicological data also argues against the lead protection being a function of its capacity to inhibit cytochrome P‐450.
Acute renal and hepatic effects induced by 3‐haloanilines in the fischer 344 rat
Authors: Rankin Gary O. , Valentovic Monica A. , Nicoll Derek W. , Ball J. G. , Anestis Dianne K. , Brown Patrick I. , Hubbard John L. 
Published: October 2006

AbstractHaloanilines are commonly used as chemical intermediates in the manufacture of a wide range of products. The purpose of this study was to examine the in vivo nephrotoxic and hepatotoxic potentials of the 3‐haloanilines. The in vitro effects of the 3‐haloanilines on renal function were also examined. In the in vivo experiments, male Fischer 344 rats (four rats/group) were administered a single intraperitoneal (i.p.) injection of an aniline hydrochloride (1.0 or 1.25 mmol kg−1) or vehicle. Renal and hepatic function were monitored at 24 and/or 48 h post‐treatment. None of the 3‐haloanilines were potent nephrotoxicants at either dose level. The greatest effects on renal function were observed following administration of 3‐chloroaniline at a dose of 1.25 mmol kg−1 (oliguria, glucosuria, hematuria, decreased p‐aminohippurate accumulation by renal cortical slices and increased blood urea nitrogen concentration). 3‐Chloroaniline also was the only aniline compound to increase plasma ALT/GPT activity at 48 h. In the in vitro experiments, the ability of an aniline (10−5–10−3M) to decrease organic ion accumulation in renal cortical slices from untreated rats was examined. The decreasing order of in vitro nephrotoxic potential was 3‐iodoaniline > 3‐bromoaniline > 3‐chloroaniline > aniline > 3‐fluoroaniline. These results indicate that the 3‐haloanilines are not potent nephrotoxicants or hepatotoxicants at sublethal doses. In addition, the reasons why the 3‐haloanilines have different orders of nephrotoxic potential in vivo and in vitro are not clear at this time.
Potency ranking of methemoglobin‐forming agents
Authors: French C. L. , Yaun S.‐S. , Baldwin L. A. , Leonard D. A. , Zhao X. Q. , Calabrese E. J. 
Published: October 2006

AbstractThis study represents the first systematic attempt to rank methemoglobin‐forming agents. It is a quantitative potency ranking study utilizing linear regression analysis of dose‐response data for comparative purposes. Six agents that are direct‐acting and eight that require bioactivation were tested for their ability to induce methemoglobin formation in Dorset sheep erythrocytes under defined in vitro conditions. The agents were then ranked according to three complementary methods based on the slope of the linear regression, the calculated dose expected to induce a given amount of methemoglobin formation and the calculated percentage methemoglobin response induced by 1 mmol 1−1 of the agent. The direct‐acting agents, ranked from most to least potent inducers of methemoglobin formation, are: p‐dinitrobenzene > o‐dinitrobenzene > copper = nitrite > chlorite > chlorate. The ranking from most to least potent inducers of the bioactivated agents are: α‐naphthol > p‐nitroaniline > m‐nitroaniline, o‐nitroaniline > p‐nitrotoluene = aniline > m‐nitrotoluene = o‐nitrotoluene. The ranking procedures are discussed and issues of interindividual variation and agent‐specific sensitivities are addressed.
Monoisoamyl and mono‐n‐hexyl meso‐2,3‐dimercaptosuccinate in mobilizing 203hg retention in relation to age of rats and route of administration
Authors: Kostial K. , Blanuša M. , Piasek M. , Prester Lj. , Jones M. M. , Singh P. K. 
Published: October 2006

AbstractMonoisoamyl (Mi‐ADMS) and mono‐n‐hexyl (Mn‐HDMS) monoesters of meso‐2,3‐dimercaptosuccinic acid (DMSA) were given orally or parenterally for the mobilization of inorganic mercury in suckling and older rats. Chelators were administered at a dose of 2 × 0.5 mmol kg−1 on two consecutive days 2 weeks after a single 203Hg injection. Six days later, whole‐body, kidney, liver and brain radioactivities were determined in gamma scintillation counters.Both Mi‐ADMS and Mn‐HDMS were found to be superior to DMSA in mobilizing mercury from body and organs. The results were similar after oral or parenteral treatment. The efficiency of both monoesters was even higher in younger than in older rats. This is the first report on the mobilization of mercury from the body of sucklings under conditions of late oral treatment.
Histopathological changes in the respiratory tract of mice exposed to ten families of airborne chemicals
Authors: Zissu D. 
Published: October 2006

AbstractThe objective of this experimental work was to identify and compare the histopathological changes induced in the respiratory tract of Swiss mice exposed to repeated inhalation (4, 9 or 14 days) at typical concentrations of RD50, 0.3 × RD50 and 3 × RD50 of airborne chemicals. These substances were selected from ten chemical families: aldehydes, organic acids, alcohols, ketones, ethers, aromatic hydrocarbons, halogenated aromatic hydrocarbons, inorganic bases, amines and isocyanates.These experiments showed that the lesion intensity observed in the nasal passages varied with exposure duration and type of airborne chemical, but did not depend on the concentration of the substance. Results did not allow us to establish a relationship between the histopathological changes and the type of chemical family. No injuries were observed in trachea and lungs.
Effects of zearalenone and/or tamoxifen on swine and mink reproduction
Authors: Yang H.‐H. , Aulerich R. J. , Helferich W. , Yamini B. , Chou K. C. , Miller E. R. , Bursian S. J. 
Published: October 2006

AbstractTamoxifen (TAM), which binds to estrogen receptors and can act as an estrogen antagonist, was incorporated into the diets of swine and mink to determine if it would ameliorate the effects of the estrogenic mycotoxin zearalenone (ZEN). Sows and female mink were fed diets containing 2 ppm (swine) or 20 ppm (mink) ZEN and/or 10 ppm TAM from day 30 of gestation through weaning (swine) or from 2 months prior to breeding through weaning (mink). The diets containing ZEN and/or TAM did not adversely affect reproduction in the sows. Although some hyperestrogenic effects on testes, uterine and ovarian weights were observed in the F1 piglets at 21 days of age, subsequent breeding performance was not affected. All the female mink exposed to ZEN mated, but only 25% whelped. No mink fed TAM (singly or in combination with ZEN) mated. Necropsy of these unmated females fed TAM revealed consistent severe pyometra. Histological examination of the reproductive tracts of the ZEN, TAM and ZEN + TAM‐treated mink showed similar alterations, including ovarian follicular atrophy and degeneration, and mild to severe uterine atrophy, pyometra and endometritis. The results of these studies indicate that TAM was not effective in ameliorating the hyperestrogenic effects of ZEN in swine and mink, but rather it acted as an estrogen agonist.