bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neuropathy target esterase in human lymphocytes and platelets
Authors: Maroni M. , Bleecker M. L. 
Published: October 2006

AbstractThe target enzyme in organophosphorous‐induced delayed neuropathy (OPIDN) has been designated neuropathy target esterase or neurotoxic esterase (NTE). NTE activity can be measured in blood lymphocytes and platelets, which could be of use as biomonitors in man at risk for the development of OPIDN. Separation of lymphocytes and platelets from whole blood, recovery, purity, storage and expression of data were examined. A substantial amount of the NTE activity of a human lymphocyte preparation made using Ficoll/Pacque was due to contamination by platelets; further purification was achieved by sucrose‐gradient centrifugation. In an easily prepared sample of human platelets less than 10% of NTE was associated with contaminating white cells. We were unable to preserve NTE activity of platelets or lymphocytes at −80°C either ‘dry’ or with added buffer and glycerol. In 68 male subjects, NTE activity in platelets averaged 8.36±1.54 nmol min−1 mg protein−1 and NTE activity in lymphocytes, obtained from blood after removal of platelets, 13.34±2.42 nmol min−1 mg protein−1. A good correlation was found between platelet and lymphocyte NTE activity. NTE activity in platelets may be a preferable method for measuring exposure to axonopathic organophosphorous compounds because of the ease and purity of separation. No correlation with other neuropathic risk factors such as age, smoking and alcohol intake was noted.
Effect of ascorbic acid on humoral and other factors of immunity in coal‐tar exposed workers
Authors: Dobiáš Lubomír , Lochman Ivo , Machálek Jan , Šrám Radim 
Published: October 2006

AbstractA group of 30 coal‐tar workers was treated with 1 g of ascorbic acid (AA) orally five times a week for 3 months. The effect of this treatment was assessed on serum IgG, IgM, IgA, α1‐antitrypsin, prealburmin, orosomucoid, transferrin, α2‐macroglobulin, C‐reactive protein, ceruloplasmin, the latex fixation test and cancer serum index (CSI). After 3 months treatment the concentration of AA in the blood increased from 9.52 to 60.75 μmol 1−1 (i.e. from 0.15 to 1.07 mg 100 ml−1), prealbumin increased from 0.37±0.08 g 1−1 to 0.48±0.08 g 1−1 (P < 0.01), CSI decreased from 2.28±0.88 to 1.76±0.50 (P <0.01) and α2‐macroglobulin decreased from 3.40±0.95 to 2.06±0.39 g 1−1 (P <0.01). These findings, together with reports that AA is a strong stimulator of xenobiotic biotransformatin in the liver, support the use of AA as a prophylactic agent for coal‐tar exposed workers.
Deposition of ultrafine aggregate particles in exercising rats
Authors: Hesseltine Gregg R. , Wolff Ronald K. , Mauderly Joe L. , Cheng Yung‐Sung 
Published: October 2006

AbstractThe effect of exercise on particle deposition in rats was investigated. Twenty male rats were trained to run on a treadmill and were exposed to gallium‐67 oxide (67Ga2O3) particles (0.1 μm activity median diffusion diameter) for 30 min while running at 30m min−1. Twenty resting controls were exposed in the same system while confined in wire mesh cages. Ten exercising and 10 resting rats were killed 2 h and 12 days after exposure. Tissue radioactivity levels of 67Ga2O3 were measured and normalized for differences in exposure concentration and body weight. Significantly (P<0.05) more 67Ga was deposited in the nasal passages (20 vs 5 nCi) and in the trachea and mainstem bronchi (0.5 vs 0.03 nCi) of exercising rats than in resting rats. There were no significant differences between the exercising and resting rats in amounts of 67Ga in the lung lobes at 2 h after exposure. Using assumed minute volumes, exercising rats had a significantly (P<0.05) lower lung deposition effeciency, expressed as percentage of estimated inhaled material, than did resting rats (3 vs 10%). The results suggest that exercising rats inhale more ultrafine particles, but deposit a smaller fraction of them in their lungs. The result is a similar lung burden of 0.1 μm particles in resting and exercising animals.
Effects of methyl mercuric chloride and sulfhydryl inhibitors on phospholipid synthetic activity of lymphocytes
Authors: Kageyama Katsuhiro , Onoyama Yasuto , Kano Eiichi 
Published: October 2006

AbstractThe effect of methyl mercuric chloride on the activity of phospholipid synthesis of rat lymph node lymphocytes was compared with that of sulfhydryl inhibitors. Measurement of the radioactivity of [14C]oleic acid and [14C]acetate incorporated into lecithin of cells during short‐term incubation showed that all the inhibitors tested similarly reduced the incorporation. However, methyl mercuric chloride (MMC) was the strongest inhibitor, being effective at 4 μM, and causing more than 80% decrease at 20 μM. Inhibition by the sulfhydryl inhibitors, at less than 40 μM, ranked as follows: N‐ethylmaleimide > α‐chloroacetophenone > hydroquinone > iodoacetamide. MMC also obstructed the enhancement by phytohemagglutinin of [14C]oleic acid incorporation into lecithin. MMC was effective at 2 μM, while the other agents had little or no effect at this concentration. Further investigation suggested that inhibition of phospholipid synthesis did no depend on reduced incorporation of oleic acid into the cellular membrane but on decreased turnover of the fatty acid into phospholipids after the incorporation. The viability of lymphocytes incubated with the agents was measured by trypan blue dye‐exclusion test. More than 90% of the cells treated with MMC at a concentration as low as 20–40 μM died, but the SH inhibitors, including NEM which greatly inhibited the phospholipid synthesis, produced few cell deaths at these concentrations. These observations show that the SH inhibitors affect enzymes in phospholipid synthesis, whereas MMC not only inhibits the enzymes but kills cells.
The teratogenic effect of phenobarbital on the embryonic chick heart
Authors: Nishikawa Toshio , Bruyere Harold J. , Takagi Yasuo , Gilbert Enid F. , Matsuoka Rumiko 
Published: October 2006

AbstractPhenobarbital was observed to produce cardiovascular malformations in embryonic chicks. Malformations included simple ventricular septal defects, ventricular septal defect associated with dextroposition of the aorta, double outlet right ventricle, and several types of aortic arch anomalies. Embryos were exposed to phenobarbital at doses of 1–25 μmol on day 4 of incubation (Hamburger‐Hamilton development stage 24). Doses equal to and greater than 5 μmol phenobarbital (26 mg/kg egg) significantly increased the frequency of embroys with cardiovascular malformations compared with lesser doses and with saline. A significant reduction in heart rate and abnormal rhythm of the heart were observed in embryros treated with teratogenic doses of phenobarbital. No arrhythmia nor significant changes in heart rate were observed in embryos exposed to subteratogenic doses of phenobarbital or to saline.
The effect of composite oral treatment for internal contamination with several radionuclides on 131I thyroid uptake in humans
Authors: Šimonović I. , Kargačin B. , Kostial K. 
Published: October 2006

AbstractThe efficiency of a composite oral treatment on 131I thyroid uptake was investigated in three adult volunteers. The treatment consisted of 10 g of calcium alginate, 3 g ferrihexacyanoferrate(II), 130 mg of potassium iodide and 5 g of Zn‐DTPA. This mixture when administered 30 min before 131 I almost completely blocked the 131 I thyroid uptake. This indicates that simultaneous administration of other antidotal agents do not cancel or decrease the effect of potassium iodide on 131 I thyroid uptake. The finding deserves attention since composite oral treatment is the recommended therapy in cases of accidental environmental exposure to several radionuclides.
Lung development and postnatal survival for rats exposed in utero to a high‐boiling coal liquid
Authors: Springer D. L. , Hackett P. L. , Miller R. A. , Buschbom R. L. 
Published: October 2006

AbstractPrevious studies performed in this laboratory indicated that exposure of rat fetuses to high‐boiling coal liquids from 12–14 days of gestation (dg) induced a number of major malformations, including cleft palate, diaphragmatic hernia and small lungs. The study reported here was designed to determine postnatal viability and development of survivors following in utero exposure to Harmarville process solvent (HPS), a wideboiling‐range (150 to > 455°C) coal liquid. For this study, 0.74 g kg−1 of the coal liquid was administered (by intragastric intubation) to rats from 12 to 14 dg. Offspring were evaluated for postnatal survival, growth and lung and thymus weights. Randomly selected pups from control and treated liters were killed and necropsied at 1, 3, 7 and 21 days postpartum. In addition, data for control pups were obtained at 0.25 and 0.5 days postpartum for comparison with body, lung and thymus weights of pups that died during this interval. Fifty‐four per cent of the exposed pups and 9% of the control pups died between birth and 3 days postpartum. Of the treated pups that died, 10% (6/5; pups/litters) had cleft palate, 27% (17/9) had small lungs and 33% (21/8) had both cleft palate and small lungs. No gross malformations were observed in the remaining 30% of the dead pups. Microscopic examination of lungs from HPS‐treated pups revealed no evident histological abnormalities. Body, lung and thymus weights for treated animals that died were significantly less than those of controls. Surviving exposed pups weighed significantly less than control pups from 0.25 to 21 days postpartum and their thymus weights were also depressed through 21 days postpartum. These data suggest that retarded lung growth during prenatal life as a result of in utero exposure to the coal liquid contributes to a significant portion of the observed neonatal mortality. Furthermore, lung weights of survivors, although significantly lower than control values through 7 days postpartum, appeared to have recovered by 21 days postpartum.
Neurotoxicity assessment of O‐ethyl‐O'‐(2‐diisopropylaminoethyl) methylphosphonite (QL) in hens
Authors: Olajo E. J. , Bergmann J. , Weimer J. T. , Wall H. 
Published: October 2006

AbstractO‐ethyl‐O'‐(2‐diisopropylaminoethyl) methylphosphonite (QL), an intermediate in the formation of ethyl S‐2‐diisopropylaminoethyl methylphosphonothiolate, was evaluated for neurotoxicity in the adult hen. Birds were given a single oral dose of QL ranging from 635 to 6080 mg kg−1. The QL‐treated hens were observed for up to 24 h after dosing for acute toxicologic effects and over a 24 d post‐dose period for evaluation of delayed neurotoxicity. The oral LD50 in hens is 1186 mg kg−1. Neurologic dysfunction, as evidenced by motor incapacitation, was observed at 6 days and thereafter after treatment with QL. Neurotoxic esterase (NTE) activity was not inhibited at 24 h after exposure to compound. Neural damage, multifocal in nature, was noted in the peripheral nervous system of QL‐treated hens at dose levels ≥ 635 mg kg−1, oral dose. These findings indicate neural damage tendencies following QL exposure.
Estimation of acute oral toxicity in rates by determination of the approximate lethal dose rather than the LD50
Authors: Kennedy Gerald L. , Ferenz Rayanne L. , Burgess Bruce A. 
Published: October 2006

AbstractThe approximiate lethal dose (ALD) to rats following oral administration of nine chemicals was determined. The ALD (lowest dose at which death was produced) for each chemical was used to define the general order of toxicity as being either extremely, highly, moderately, slightly, or practically non‐toxic. For each of the nine chemicals tested, the category indicated by the ALD was identical with the category determined in the more extensive LD50 studies. In this study, an average of 6.8 rats was needed to determine the ALD while an average of 56.3 rats was needed to determine the LD50.
Reproductive and teratological effects of continuous low‐level dietary T‐2 toxin in female CD‐1 mice for two generations
Authors: Rousseaux C. G. , Schiefer H. B. , Hancock D. S. 
Published: October 2006

AbstractA two‐generation female reproduction and teratology study was undertaken using 0, 1.5 and 3.0 ppm of T‐2 toxin in a semisynthetic diet. Conception rate was lowest at the first breeding and lowest in the control group at this time, but in later breedings the conception rates of each group were very similar. No significant differences were noted in litter size, death of fetuses, sex of fetuses and gestational length. Feed consumption was similar in all groups, as were the non‐pregnant or pregnant female weight gains. Although the second‐generation offspring grew faster than the first‐generation offspring, and significantly lower body weights were seen in the 3.0 ppm T‐2 toxin group at 2, 5 and 6 weeks of age, all offspring reached the normal weight for CD‐1 mice at 6 weeks of age. Gross and histological evaluation of all animals at postmortem examination did not reveal any significant results, nor were there significant differences in major and minor or retardation defects among the treatment groups. Relative spleen weights of the second‐generation offspring were significantly higher in control females compared with the treated groups but treated males had significantly increased relative spleen weights compared with control males of this generation. It was concluded that no long‐term reproductive and teratological effects of low‐dose dietary T‐2 toxin were found in this study.
1984 survey of genetic toxicology testing in industry, government and academic laboratories
Authors: Farrow M. G. , McCarroll N. E. , Auletta A. E. 
Published: October 2006

AbstractComplied results of the 1984 Genetic Toxicology Association's survey representing a total of 72 responses from governmental, contract, industrial, or academic institutions regarding the status of 32 recognized genetic toxicology assays, were as follows:

Most frequently performed on a routine or occasional basis: Ames (76% of all respondents routinely or occasionally perform the assay); in vitro cytogenetics (59%); in vivo Bone Marrow Cytogenetics (56%); in vitro Sister Chromatid Exchange (56%); in vitro Unschedled DNA Synthesis (43%); Mutation in CHO HGPRT (42%); Micronucleus test (41%); Mutation in L5178Y (36%).
Assay associated with in vivo and in vitro chromosomal end points (aberrations, SCE, micronucleus) constituted the major area of increased use since the 1982 survey.
Assays of developmental interest included DNAS binding both in vitro and in vivo and UDS in vivo.

Quantitative analysis of the data indicated:

Industrial and contract laboratories processed the largest volumes of chemicals over the broadest spectrum of assays.
Industrtial laboratories showed a marked increased since 1982 in testing compounds in‐house.
The number of assays sponsored by governmental laboratories, both in‐house or subcontracted, increased from 1982.
Academic institutions ranked lowest in number of compounds examined.
Pulmonary toxicity of the insecticide fenitrothion in the rat following a single field exposure
Authors: Coulombe P. A. , Lortie S. , Cčte M. G. , Chevalier G. 
Published: October 2006

AbstractThe pulmonary toxicity of the organophosphorus insecticide fenitrothion was evaluated following a single exposure of rats to the field formulation, at the site of an aerial spraying. Four groups of 40 Sprague‐Dawley rats (including a control), set in wood enclosures, were placed under the aerial lines of the spraying aircraft. The degree of exposure was monitored at the ground level by air sampling and visual evidence of droplet activity deposition. Plasma pseudocholinesterase activity and pulmonary alveoli ultrastructure were used as indices to the fenitrothion exposure. Rat lungs were examined under light and electron microscopy at days 3, 7, 21, 60 and 180 after the exposure. Although a few signs of toxic lung injury were observed at days 3 and 7 there was no cholinergic crisis nor an effect on the pseudocholinesterase activity within 12 h in the exposed animals, when compared with controls. The alveolar toxic reaction was limited to small and discrete foci, and was entirely reversible within a period of 2 months. On a morphological basis it is thus concluded that a single field exposure to fenitrothion did not induce any permanent change in the alveolar area of the rat lung.
Influence of chelating agents on the toxicity, distribution and excretion of vanadium in mice
Authors: Domingo J. L. , Llobet J. M. , Tomas J. M. , Corbella J. 
Published: October 2006

AbstractThe effects of the chelating agents Na2Ca‐ethylendiaminetetraacetate (EDTA), Na3Ca‐diethylentriaminepentaacetate (DTPA), L‐cysteine, 4,5‐dihydroxy‐1,3‐benzene‐disulfonic acid (Tiron) and deferoxamine mesylate and the reducing agent ascorbic acid on the toxicity, excretion and distribution of i.p. injected vanadium were studied in male Swiss mice. Chelating and reducing agents were administered intraperitoneally at doses equal to one‐forth of their respective LD50. To determine the effects of the various chelators on the mortality of vanadium, various doses of NaVO3 (0.30–1.20 mmol kg−1 i.p.) were given, followed immediately by one of the chelating or reducing agents. Survival was recorded at the end of 14 days. Significant increases in survival were noted with ascorbic acid, Tiron and deferoxamine, with ascorbic acid being the most effective. Deferoxamine and Tiron were the most effective in increasing the excretion of vanadium and reducing the concentration of vanadium found in various tissues. However, ascorbic acid appears to be the most effective agent in the prevention of vanadium intoxication.
Inhibition of tributyltin mediated hemolysis by mercapto compounds
Authors: Gray Bryan H. , Porvaznik Martin , Lee Lanfong H. , Flemming Carlyle 
Published: October 2006

AbstractHydrophobic tributylin (TBT) compounds at concentrations greater than 10 μM used hemolysis of human erythrocytes and formed structures in plasma membranes. The mercapto compounds, β‐mercaptoethanol (β MER), 2,3‐dimercaptopropanol (BAL), 2,3‐dimercapto‐1‐propane sulfonate (DMPS), DL‐dithiothreitol (DTT), and meso‐2,3‐dimercaptosuccinic acid (DMSA) were examined for their ability to inhibit TBT mediated hemolysis. The relative order of effectiveness for inhibition of TBT mediated hemolysis was BAL>DTT>DMSA>DMPS>β MER. A four‐fold excess of BAL over TBT prevented hemolysis for 4 hrs and addition of BAL 0.5 hr after TBT reduced the rate of hemolysis. The number of membrane associated TBT aggregates observed per cell profile decreased as the BAL concentration increased from 0 to 100 μM. However, the mean diameter of TBT aggregates nearly doubled in erythrocyte suspensions at 100 μM BAL. Reactions of dimercapto compounds with lipophilic TBT aggregates may depend on their relative lipid solubilities. Also, conversion of the weak Lewis acid, TBT, from a four to a five or six‐coordinate tin adduct by the dimercapto Lewis bases used could also be a factor slowing hemolysis rates.
Subacute (4‐week) inhalation toxicity study of formaldehyde in male rats: 8‐hour intermittent versus 8‐hour continuous exposures
Authors: Wilmer J. W. G. M. , Woutersen R. A. , Appelman L. M. , Leeman W. R. , Feron V. J. 
Published: October 2006

AbstractMale Wistar rats were exposed for 4 weeks, 5 days a week, to 0 (controls), 5 or 10 ppm formaldehyde continuously (8 hours a day), or to 10 or 20 ppm formaldehyde interruptedly (eight 30 min exposure periods separated by 30 min non‐exposure periods). Histopathology and cell proliferation studies indicated that under the conditions of exposure used, concentration rather than the total dose of formaldehyde determined the severity of the cytotoxic effects on the nasal epithelium.
Discovery of multiple organofluorophosphate hydrolyzing activities in the protozoan Tetrahymena thermophila
Authors: Landis Wayne G. , Haley Donna M. , Haley Mark V. , Johnson Dennis W. , Durst H. Dupont , Savage Russell E. 
Published: October 2006

AbstractRecently it has been found that homogenates of Tetrahymena thermophila can hydrolyze the potent acetylcholinesterase inhibitors O,O‐diisopropylphosphofluoridate (DFP) and O‐1,2,2‐trimethylpropylmethylphosphonofluoridate (soman). Upon purification of the DFP hydrolyzing activity 10‐fold it had been noted that the soman hydrolyzing activity increased only 2–3 fold. Treatment with manganous ion and comparison of the soman and DFP hydrolysis rates of the homogenate indicated that a mixture of the squid‐type and Mazur‐type DFPases may be present. Subsequent purification of the enzymatic activities within the Tetrahymena‐homogenate demostrated that there are at least five functioning proteins of molecular weights 67 000 to 96 000. None are directly homologous to the DFPases found in hog kidney or squid. The enzymatic activities are designated DFPase‐1 through DFPase‐5. A hypothesis is presented that the functions of DFPases are in the normal metabolism of organophosphates naturally synthesized by T. thermophila.
Subchronic (13‐week) inhalation toxicity study of formaldehyde in rats
Authors: Woutersen R. A. , Appelman L. M. , Wilmer J. W. G. M. , Falke H. E. , Feron V. J. 
Published: October 2006

AbstractMale and female albino Wistar rats were exposed to concentrations of 0, 1, 10 or 20 ppm formaldehyde vapour during 6 h/day, 5 days/wk for 13 weeks. Treatment‐related changes observed at 20 ppm included in both sexes: stared coats, uncoordinated locomotion and excitation during the first 30 minutes of each exposure, yellowing of the fur, growth retardation, a decreased level of plasma protein, severe and extensive karatinized stratified squamous metaplasia of the nasal respiratory epithelium, and focal degeneration and squamous metaplasia occasionally accompanied by keratinization of the olfactory epithelium; in males only; increased activities of plasma aspartate amino transferase (ASAT), alanine amino transferase (ALAT) and alkaline phosphatase (ALP) and squamous metaplasia of the laryngeal epithelium.Lesions seen at 10 ppm included yellowing of the fur and moderate squamous metaplasia of the nasal respiratory epithelium. The only change observed in three out of twenty 1 ppm exposed animals that might or might not be treatment‐related was minimal focal epithelial hyperplasia and squamous metaplasia of the respiratory epithelium lining the nasal septum and maxillary turbinates.No histopathological evidence of hepatotoxicity was detected in any of the formaldehyde‐treated groups.An in vivo/in vitro cell proliferation study showed an increase in [3H]‐thymiding labeling index of the respiratory epithelium lining the nasoturbinates of rats exposed to 10 or 20 ppm formaldehyde on three successive days, whereas at the 1 ppm level the labeling index was similar to that of controls. It was concluded that under the conditions of the present 13‐week inhalation study, formaldehyde at concentrations up to 10 ppm was not hepatotoxic to rats. At the 20 ppm formaldehyde level, a slight effect on the fiver of mate rats cannot be completely excluded. The study was inconclusive with respect to 1 ppm formaldehyde being a cytotoxic or a no‐cytotoxic effect level for the nasal epithelium.