bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of aflatoxin on lymphoid cells of weanling rat
Authors: Raisuddin  , Singh K. P. , Zaidi S. I. A. , Saxena A. K. , Ray P. K. 
Published: October 2006

AbstractAflatoxin (AF), the hepatocarcinogenic food contaminant produced by the Aspergillus flavus group of fungi, is known to interact with various vital processes, including the immune function. Effects of long‐term treatment of three dose levels of aflatoxin B1 (AFB1) on lymphoid cells of weanling rats were studied. AFB1 treatment caused a reduction in body weight gain, significantly (P<0.01) at the 700 μg level. There was also a significant decrease in the weight of spleen and thymus in AFB1‐treated animals in comparison to control. Similarly, AFB1 depleted cell populations of thymus and bone marrow and WBC and RBC counts. There was a marked reduction in the population and phagocytic capacity of macrophages due to AFB1 administration‐at dose levels of 350 and 700 μg kg−1 body weight. Macromolecular synthesis of DNA, RNA and protein in macrophages was affected, as there was significant inhibition in the incorporation of [3H]‐thymidine, [3H]‐uridine and [3H]‐leucine. The hampered functioning of macrophages may be due to the cytotoxic action of AFB1.
Influence of chronic lead exposure on hormone levels in developing rats
Authors: Vyskočil Adolf , Fiala Zdeněk , Ettlerová Eva , Tenjnorová Iva 
Published: October 2006

AbstractThe effect of five months' exposure to 0.5% lead acetate in drinking water on hormone levels of developing rats was studied. The hypothalamic and striatic concentrations of noradrenaline (NA) were decreased in both sexes. In female but not in male rats, blood and adrenal catecholamines and serum corticosterone concentrations were aiso increased. No changes were observed in serum thyroxine and 3,5,3′‐triiodothyronine levels. Our results indicate that female developing rats are more susceptible to lead than male rats. In female rats, both the hypothalamo‐pituitary‐adrenal and sympatho‐adrenal systems seem to be affected by this lead exposure; in male rats, only the latter system is affected.
Prevention of hydrolysable tannin toxicity in goats fed clidemia hirta by calcium hydroxide supplementation
Authors: Murdiati Tri Budhi , McSweeney Christopher S. , Campbell Roderick S. F. , Stoltz Douglas S. 
Published: October 2006

AbstractAlthough plants containing hydrolysable tannins can be hepatotoxic, such poisoning has not been reported in Indonesia despite the presence of these plants. In order to determine the hepatotoxic potential of Indonesian plants, goats were intoxicated experimentally with the Indonesian plant Climedia hirta (harendong), which cuntained 19% hydrolysable tannin. The prophylactic effect of Ca(OH)2 supplementation on the disease was also examined. Two groups of goats were fed for 28 days with grain‐based pellets containing 50% harendong leaf or 50% harendong leaf + 8% Ca(OH)2. Two control groups were fed similar pellets containing 50% of the non‐toxic elephant grass (Pennisetum purpureum) with and without 8% Ca(OH)2. Serum enzymes indicative of liver damage were monitored during the experiment and histopathological examination of selected tissues was done at the conclusion of the experiment. In goats given unsupplemented harendong pellets there was a significant increase in aspartate aminotransferase and glutamate dehydrogenase from 50.2 and 20.6 U I−1 to 219.6 and 63.3 U I−1, respectively. These changes were associated with moderate to severe nuclear pleomorphism, vacuolation and megalocytosis of hepatocytes and deposits of brown pigment in the Kupffer cells. There was also nephrosis of the renal convoluted tubules and collecting ducts, abomasitis and enteritis. Biochemical and histological changes were reduced significanty in the harendong + Ca(OH)2 group and virtually absent from control groups. It is concluded that hydrolysable tannins in harendong leaf are hepato‐ and nephrotoxic and associated with gastroenteritis, but that poisoning may be ameliorated by Ca(OH)2 supplementation.
Evaluation of the onset and duration of response to cold air inhalation challenge in Cynomolgus monkeys (Macaca fascicularis)
Authors: Biagini R. E. , Clark J. C. , Moorman W. J. , Knecht E. A. 
Published: October 2006

AbstractCold air inhalation challenge (CAIC) for the evaluation of bronchial reactivity has been proposed as a physical agent alternative to chemical agent challenges (methacholine or histamine), especially suitable for the occupational environment. The present investigation describes and evaluates a method for performing cold air inhalation challenge in Cynomologus monkeys (Macaca fascicularis), a species shown to be useful in animal modeling studies of occupational asthma. Six adult male anesthetized monkeys were ventilated by changes in external pressure while breathing cold air (−25°C to −30°C). Pulmonary function testing was performed at 10, 25, 40 and 55 min post‐challenge. Significant increases (P<0.05) in average pulmonary flow resistance (RL) and decreases in dynamic compliance (CL dyn) were observed, with maximum impairment occurring at 25 min post‐challenge, with a trend towards a return to baseline values at 55 min post‐challenge. Peak expiratory flow rate (PEFR), forced expiratory volume in 0.5 s/forced vital capacity (FEV0.5/FVC) and forced expiratory flow at 50% forced vital capacity (FEF50) showed the same general pattern of reduction as seen with RL; however, these results were not statistically significant, most probably owing to individual monkey variability and the small number of monkeys (N = 6) used. A repeat challenge at 25 min after a primary challenge yielded increased RL in one monkey, suggesting that no absolute refractory period is present from CAIC. Results of these studies demonstrate that CAIC causes bronchoconstriction in monkeys and may be useful in further animal modeling studies designed to determine the asthmogenic/airway irritant potential of occupational toxicants.
Biochemical assessment of cardiac function and damage in animal species A Review of the Current Approach of the Academic, Governmental and Industrial Institutions Represented by the Animal Clinical Chemistry Association
Authors: Evans G. O. 
Published: October 2006

AbstractSpecies differences in metabolism, tissue localization, specificity and sensitivity for cardiac damage influence the choice of biochemical investigation used in the assessment of cardiotoxicity. The tests currently used in toxicological studies are broadly categorized herein as enzymes and other proteins, lipids and electrolytes; some limitations of these tests are also discussed.
Evaluation of the embryolethality of butyl benzyl phthalate by conventional and pair‐feeding studies in rats
Authors: Ema Makoto , Itami Takafumi , Kawasaki Hironoshin 
Published: October 2006

AbstractThe embryolethality of butyl benzyl phthalate (BBP) was studied in Wistar rats. Pregnant rats were given BBP at dosages of 0 (control) and 2.0% in the diet from day 0 to day 20 of pregnancy. Daily intake of BBP was 974 mg kg−1 for the 2.0% BBP group. In this group, all dams exhibited complete resorption of all the implanted embryos, and their food consumption, body weight gain and adjusted weight gain (body weight gain excluding the gravid uterus) during pregnancy were markedly lowered. To determine whether the embryolethality was the result of reduced food consumption during pregnancy, a pair‐feeding study was performed in which the pregnant rats received the same amount of diet consumed by the 2.0% BBP‐treated pregnant rats. The pair‐fed and 2.0% BBP‐treated pregnant rats showed significant and comparable reductions in the adjusted weight gain. In the pair‐fed group, the incidences of postimplantation and total losses were higher than those in the control group, and the number of live fetuses per litter was lower than the control value. However, the complete resorption of all the implanted embryos was not found in any of the pair‐fed pregnant rats. It could be concluded that the embryolethality observed in the 2.0% BBP‐treated pregnant rats is attributable to the effects of dietary BBP but not to the maternal malnutrition from reduced food consumption during pregnancy.
In situ assessment of the rat heart during chronic carbon monoxide exposure using nuclear magnetic resonance imaging
Authors: Bambach Gregory A. , Penney David G. , Negendank William G. 
Published: October 2006

AbstractVentricular hypertrophy induced in male Sprague‐Dawley rats by inhalation of 500 ppm carbon monoxide (40% carboxyhemoglobin level) for 0–62 days was assessed by contiguous 2‐mm thick axial cardiac crosssections, using 32 accumulated averages of ungated fast‐scan gradient‐recalled nuclear magnetic resonance (NMR) images. Following final imaging, the rats were sacrificed and the hematocrit and heart mass were determined. The mean outside diameter of the left ventricle plus interventricular septum (LV + S) showed a strong correlation (r = 0.73, P<0.01) with the duration of CO exposure, while the correlation coefficients for the LV + S Iumen diameter and wall thickness were marginally significant. The mean pleural space diameter also increased significantly (r = 0.64, P<0.05) with the duration of CO exposure. The ratio of LV + S wall thickness and the Iumen radius was 0.53 in the rats exposed to CO for 0–8 days; this value did not change with longer CO exposure. The LV + S outside and Iumen diameter showed significant correlations to the hematocrit (r = 0.72, p<0.05 and r = 0.66, P<0.05, respectively), and the LV + S outside diameter correlated with the increase in the LV + S mass (r = 0.72, P<0.05). The results achieved with NMR imaging are consistent with past morphometric studies of CO‐induced ventricular hypertrophy, where heart dimensions were determined in relaxed frozen tissue, and corroborate the eccentric nature of CO‐induced ventricular hypertrophy.
Cyanide‐induced alteration of the adenylate energy pool in a rat neurosecretory cell line
Authors: Maduh Edward U. , Borowitz Joseph L. , Isom Gary E. 
Published: October 2006

AbstractCultures of a rat PC12 pheochromocytoma neurosecretory cell line were used to determine the responsiveness of oxidative energy status of isolated neuronal cells to cyanide exposure. Intracellular levels of ATP and its immediate metabolites, ADP and AMP, were measured in monolayer cultures of PC12 cells incubated for 0–30 min with KCN (10 mM). Over the period 2.5–30 min, cyanide treatment decreased ATP levels by 32–51% but ADP and AMP levels were not altered significantly. Additionally, ATP/ADP and ATP/AMP ratios were significantly reduced in KCN‐intoxicated cells. These alterations in energy status may explain the prompt ablation of ion homeostasis reported previously in this model upon exposure to KCN. The energy‐depleting actions of cyanide were not modified by pretreatment of cells with diltiazem, a calcium channel antagonist demonstrated to possess cytoprotective activity against histotoxic hypoxia induced by cyanide. Since PC12 cells rapidly respond to cyanide, with predictable depletions of the cell adenylate energy pool, this cell line can serve as a suitable in vitro model for studies of neurotoxicity involving ischemic/hypoxic conditions.
A comparison of the effects of inorganic and alkyllead compounds on human erythrocytic δ‐aminolevulinic acid dehydratase (ALAD) activity in vitro
Authors: Burns C. B. , Godwin I. R. 
Published: October 2006

AbstractA study comprising two experiments comparing the effects of the alkyllead compounds triethyllead acetate and tetraethyllead as well as an inorganic lead compound (Pb(NO3)2) on human erythrocytic δ‐aminolevulinic acid dehydratase activity was undertaken. In Experiment 1, four human blood samples were pre‐incubated for 0 min or 60 min with increasing concentrations (0–1000 μM) of triethyllead acetate, tetraethyllead and Pb(NO3)2, and the δ‐aminolevulinic acid dehydratase activity was determined. There was no discernible inhibitory effect of tetraethyllead at any concentration, with or without pre‐incubation. Pb(NO3)2 showed a distinct effect at an addition concentration of 1 μM, with a substantial inhibition only following pre‐incubation. Triethyllead acetate showed no difference in effect with pre‐incubation. In the second experiment, the activating effects of zinc chloride (60 μM) and dithiothreitol (20 mM) on δ‐aminolevulinic acid dehydratase activity were examined on four human blood samples in the presence of varying concentrations of Pb(NO3)2 (0–50 μM) and triethyllead acetate (0–1000 μM). The addition of zinc chloride alone showed little effect on enzyme activity, while dithiothreitol alone caused a substantial activation of the enzyme at all lead concentrations. The addition of both zinc chloride and dithiothreitol caused an even greater activation of the enzyme. The data indicate that Pb(NO3)2 is a much more potent inhibitor of δ‐aminolevulinic acid dehydratase activity than triethyllead acetate (Ki values of 0.77 μM versus 130.37 μM, respectively). The use of δ‐aminolevulinic acid dehydratase activity as an indicator of exposure may be questionable in cases of alkyllead exposure. Possible causes for differences in the inhibition of δ‐aminolevulinic acid dehydratase by these compounds is also discussed.
Cardiopathic effect of 1,2,3‐trichloropropane after subacute and subchronic exposure in rats
Authors: Merrick B. Alex , Robinson Merrel , Condie Lyman W. 
Published: October 2006

Abstract1,2,3‐Trichloropropane (1,2,3‐TCP) is an industrial water contaminant with potential for human exposure by the oral route. The systemic toxicology of 1,2,3‐TCP was evaluated after subacute or subchronic exposure in male and female Sprague‐Dawley rats. Animals were treated with 0.01, 0.05, 0.20 and 0.80 mmol kg−1 day−1 for 10 days and 0.01, 0.05, 0.10 and 0.40 mmol kg−1 day−1 for 90 days. Chemical exposure was by oral gavage in corn oil. Lethality did not occur in either study. Toxicity was observed primarily in the high dose group of subacute and subchronically treated rats of both sexes. Weight gain suppression occurred at a dose of 0.8 mmol kg−1 (118 mg kg−1) after 10 days. After 90 days of exposure to 0.40 mmol kg−1, the final body weights were 81% and 86% of control values for males and females, respectively. When major organ weights were normalized by body weight, liver and kidney values were generally increased relative to control in the two highest dose groups after 10‐ and 90‐day chemical exposure. Serum chemistries and histopathology indicated a mild hepatotoxic response to 1,2,3‐TCP in the high dose group of each study but did not support any renal toxicity. Thymic weight reduction due to atrophy occurred at 10 days of exposure in high dose groups but was normal in all groups after the 90‐day treatment. The primary histological finding in this study was an inflammation‐associated cardiopathy produced by 1,2,3‐TCP. Myocardial necrosis and degeneration occurred in a diffuse pattern with marked eosinophilia of affected cells. Male and female animals showed a cardiopathic response only at a dose of 0.8 mmol kg−1 1,2,3‐TCP after the 10‐day exposure. In the subchronic study, the incidence of cardiopathy was more prevalent in males than in females. In addition to cardiac effects, the 90‐day chemical exposure produced bile duct hyperplasia in 40% and 80% of males and females, respectively. This observation may be significant, since five other neoplastic and proliferative lesions were observed in rats receiving 1,2,3‐TCP subchronically. Thus, this study demonstrates that heart and liver were target organs for 1,2,3‐TCP toxicity and suggests that 1,2,3‐TCP exposure may be involved in carcinogenesis.
Four‐week inhalation exposures of rats to aerosols of three lubricant base oils
Authors: Dalbey W. , Osimitz T. , Kommineni C. , Roy T. , Feuston M. , Yang J. 
Published: October 2006

AbstractSprague‐Dawley rats were exposed to aerosols of one of three base stocks used to formulate lubricating oils. These stocks were a solvent‐refined oil (SRO), a hydrotreated and acid‐washed white oil (WTO) and a severely hydrotreated and hydrocracked oil (HBO). Exposures were for 6 h per day, 5 days per week for ca. 4 weeks. There were four groups of rats for each study (10 per sex per group). Aerosol concentrations were ca. 0, 50, 210 and 1000 mg m−3 for each material; the mass median aerodynamic diameter was ca. 1 μm. Following the last exposure, all animals were sacrificed and necropsied. Samples were taken for serum chemistry, hematology, sperm morphology, weights of seven organs and histopathology on at least nine organs. Body weights and clinical signs were not affected by exposures. The only treatment‐related changes were in the lung and associated lymph nodes. Both the wet weight of the lung and the dry/wet weight ratio increased in a concentration‐related manner. Associated with the increased weight were accumulations of foamy alveolar macrophages, particularly in alveoli close to alveolar ducts. Mild infiltration by neutrophils was observed with WTO and SRO; thickened alveolar walls were noted with the highest concentration of HBO. These mild responses to exposures at very high concentrations indicate a low degree of toxicity for these aerosols.
Ultrastructural localization of silver in rat testis and organ distribution of radioactive silver in the rat
Authors: Ernst Erik , Rungby Jørgen , Baatrup Erik 
Published: October 2006

AbstractThe deposition of silver after a single intravenous injection (2 μg Ag g−1 body weight) was studied in the testes of Wistar rats 24 h and 1 and 2 weeks after dosing with radiolabelled 110AgNo3 (2 μg Ag and 1.2 kBq g−1 body weight). Also, the temporal accumulation of silver during the experimental period was monitored in the blood, testes, epididymides, kidney, liver and brain.The subcellular distribution of silver within the testes was demonstrated by using the histochemical technique of autometallography. Silver was cleared rapidly from the blood. After an initial rise, concentrations in organs remained almost stable throughout the experimental period.Silver was especially abundant in interstitial macrophages and in the basement membrane. Deposits of silver were found in all cell types of spermatogenesis and in the lysosomes of the Sertoli cells.
Serum histamine and the elicitation of murine contact sensitivity
Authors: Kimber Ian , Cumberbatch Marie , Coleman John W. 
Published: October 2006

AbstractWe report that challenge of previously contact‐sensitized mice results in a significant increase in the concentration of serum histamine. In an attempt to determine whether this phenomenon might form the basis of an alternative method for the evaluation of elicitation reactions in experimental contact sensitivity, we have compared challenge‐induced increases in ear thickness with elevations in serum histamine. Challenge of sensitized mice revealed that both ear thickness changes and increases in the serum level of histamine were dependent upon the concentration of oxazolone used for sensitization. The kinetics of changes in serum histamine concentration were found to be biphasic, with a small increase measurable 2 h following challenge and the maximal response at 24 or 48 h. In contrast, increases in ear thickness were monophasic, although maximum responses were also observed at 24 h. It is concluded that, although they do not exactly parallel increases in ear thickness, changes in histamine concentration may provide a useful serological correlate of the challenge reaction in contact sensitivity.
Inhalation toxicity of furfural vapours: An assessment of biochemical response in rat lungs
Authors: Gupta Ghanshyam D. , Misra Anil , Agarwal Deepak K. 
Published: October 2006

AbstractThe pulmonary biochemical response, particularly the effects on mixed‐function oxidases, was investigated in rats exposed to 40 ppm furfural for 1 h daily, 5 days per week, for periods of 7, 15 and 30 days. This concentration is ca. 22% of the acute LC50 dose. Exposure to furfural increased the activities of acid and alkaline phosphatases and glutamic‐pyruvic transaminase, inhibited the activities of arginase and succinic dehydrogenases and elevated the concentration of lactic acid in the lungs. In the group of mixed‐function oxidases, the activities of aminopyrene‐N‐demethylase and aniline hydroxylase (phase I, cytochrome P‐450b specific) significantly increased and the activity of Benzo[a]pyrene hydroxylase (phase I, cytochrome P‐450c specific) decreased. The activity of glutathione‐S‐transferase (phase II component) also was increased concurrently with a decrease in the concentration of glutathione. The magnitude of biochemical alterations in most cases was related directly to the duration of exposure. Our observations indicate that furfural caused pulmonary irritation, parenchymal injury and the regenerative proliferation of type II pneumocytes. Selective (cellular and/or cytochrome P‐450 isozyme specific) enhancement of pulmonary mixed‐function oxidases by furfural appears to stimulate its own pulmonary biotransformation, and the excretion of oxidative metabolites was facilitated by their enzymatic conjugation with glutathione.
In vitro effects of organophosphorus compounds on calmodulin activity
Authors: Pala I. , Vig P. J. S. , Desaiah D. , Srinivasan A. 
Published: October 2006

AbstractIn vitro effects of organophosphorus compounds (OP), such as malathion (M), methyl parathion (MP) and ethyl parathion (EP), on calmodulin (CaM) activity and its active conformation were studied to understand the mechanism(s) of neurotoxicity, since CaM is known to regulate Ca2+ transport and the enzymes involved in signal transduction and nucleotide metabolism. The biological activity of CaM was assessed as a measure of phosphodiesterase (PDE) stimulation. The effect of OP compounds on the active conformation of CaM was determined by studying the binding of fluorescence probes, namely N‐phenyl‐1‐naphthylamine (NPN), and changes in dansyl‐calmodulin fluorescence. Dansylated calmodulin was also used to study the effect of OP compounds on complex formation between CaM and PDE. All three OP compounds inhibited the CaM activity and its active conformation in a concentration‐dependent manner. Malathion was less effective in comparison to EP and MP, with IC50 values of 37 μM, 34.5 μM and 32 μM, respectively, for CaM activity. EP and MP significantly altered NPN and dansyl‐calmodulin fluorescence (50 μM concentrations of OP compounds), whereas M did not show any significant effect on NPN fluorescence. All these compounds significantly affected complex formation between the dansylated CaM and PDE. These results suggest that OP compounds may be interacting with CaM, altering its active conformation, and thus may be inhibiting its biological activity.