摘要:

AbstractThis study was performed to evaluate the effect of oral and intraperitoneal treatment withN‐(4‐methoxybenzyl) D‐glucamine dithiocarbamate monohydrate (MeOBDCG) after a single oral administration of115mCd to 6‐week‐old rats. Oral treatment reduced the retention of115mCd in the whole body, gut, liver and kidney by 5, 3, 4 and 3 times respectively, and intraperitoneal treatment reduced the retention by 7,2.5, 16 and 4.5 times, respectively. This finding is new, since it was believed that oral dithiocarbamate treatment would increase the toxicity and absorption of ingeste

ISSN:0260-437X    

DOI:10.1002/jat.2550110503

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe deposition of silver after a single intravenous injection (2 μg Ag g−1body weight) was studied in the testes of Wistar rats 24 h and 1 and 2 weeks after dosing with radiolabelled110AgNo3(2 μg Ag and 1.2 kBq g−1body 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

ISSN:0260-437X    

DOI:10.1002/jat.2550110504

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractFour groups of 40 Wistar rats of each sex per dose level were fed diets containing 0, 80, 400 or 2000 ppm of the magnesium salt of bis(2,3‐dibromopropyl)phosphate (Bis‐BP) for 24 months. A high incidence of tumours was induced, in both sexes, in the digestive system. Tumours included papillomas and adenocarcinomas of the tongue, oesophagus and forestomach, adenocarcinomas of the intestine and hepatocellular adenomas (neoplastic nodules) and carcinomas. Pre‐terminal mortalities were associated with an increased incidence of forestomach papillomas in both sexes, adenocarcinomas of the small intestine in male rats and increased incidence of hepatocellular carcinomas in females. The data suggest that Bis‐BP is a more potent proximate carcinogen than tris‐(2,3‐dibromopropyl)phosphat

ISSN:0260-437X    

DOI:10.1002/jat.2550110505

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractRuminants consuming either tannic acid or hydrolysable tannins from the Australian yellow‐wood tree (Terminalia oblongata) and the Indonesian shrubClidemia hirtaare intoxicated by simple phenolics liberated in the gut. The affinity of these tannins and of the simple phenolic gallic acid for the two proteins casein and pepsin, polyvinylpyrolidone (PVP), activated charcoal and Ca(OH)2was examinedin vitro.The studies were undertaken to predict the effect of these phenolics on digestion and to identify substances that would act as antidotes by precipitating phenolics. Tannins but not gallic acid were precipitated as stable complexes with both pepsin and casein at pH 3–5. Optimal complexing of tannin with protein occurred at a weight ratio of 1:1. Ionic strength and temperature did not affect the amount of tannin precipitated from solution with protein. The precipitation of tannins with PVP and Ca(OH)2was unaffected by pH within the range 2–8 while maximum binding with activated charcoal occurred between pH 3 and 7. In contrast to protein, the other substances complexed with gallic acid; only gallic acid‐PVP complexess were affected by pH. Calcium hydroxide bound more tannin and gallic acid on a weight basis than PVP and charcoal. Both Ca(OH)2and activated charcoal should complex with phenolics in the forestomach, abomasum and intestines.The reaction of hydrolysable tannins and proteins at the pH found in the abomasum suggests that hydrolysable tannins would interfere with enzyme function and protein digestion post‐ruminally rather than in the fo

ISSN:0260-437X    

DOI:10.1002/jat.2550110506

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

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 sensitiv

ISSN:0260-437X    

DOI:10.1002/jat.2550110507

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

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 LC50dose. 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 conjuga

ISSN:0260-437X    

DOI:10.1002/jat.2550110508

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe effect of extracellularly applied Cu2+was studied on isolated intracellularly perfusedHelix pomatia neurons.It was found that the Cu2+‐activated current (ICu) is biphasic and composed of overlapping outward and inward components. The outward component ofICuis the result of a blockade by Cu2+of the steady‐state outward Cl−current. The inward component is assumed to flow through Ca2+‐activated non‐selective cationic channels. The washing‐out procedure resulted in a large inward current (Iw), which was composed of transient and steady‐state components. It is most likely that the activation of metabolic pumps is responsible for the transient component and the steady‐state component is the result of increased neuronal membrane permeability for Cl−. Moreover, bothICuandIwwere highly Ca2+‐ and temperature‐dependent processes. It is concluded that Cu2+application resulted in complex permeability changes in the

ISSN:0260-437X    

DOI:10.1002/jat.2550110509

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractCigarette smoking constitutes a major source of cadmium exposure via inhalation in man. To determine how smoke exposure affects the organ distribution and accumulation of cadmium, male C57B1 mice and Sprague‐Dawley rats were exposed daily for 52–60 consecutive weeks to mainstream smoke from the University of Kentucky reference cigarettes (2R1) in a nose‐only exposure system. Exposed mice and rats averaged blood carboxyhemoglobin values of 17.7 and 7.2%, and a daily total particulate matter (TPM) dose of 7.2 and 3.2 mg kg−1body wt. per exposure, respectively. These results suggested effective inhalation of smoke by the animals. The tissues were acid digested and analyzed for cadmium by atomic absorption spectrometry. Cadmum levels 5–6‐ and 2–3‐fold greater than control levels were detected in the lungs and kidneys, respectively, of exposed animals of both species. In contrast, the liver did not show increased cadmium levels in exposed mice or rats. The data suggest that low‐dose chronic inhalation exposure to cigarette smoke leads to highest cadmium accumulation in the lung, followed by the kidney, with minimal effects on cadmium le

ISSN:0260-437X    

DOI:10.1002/jat.2550110510

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractStrand breaks in hamster lung DNA were analyzed followingin vivoexposure to bleomycin. An alkaline unwinding procedure involving separation of single‐strand from double‐strand DNA by hydroxylapatite chromatography followed by fluorescence detection of DNA with bisbenzimide was adapted for these studies. Procedures were developed that allowed preparation of DNA from lungs of control animals with a relatively low amount of single‐strand DNA relative to double‐strand DNA. Time dependence of unwinding was demonstrated using samples that were damaged deliberately by brief probe sonication. To verify that residual bleomycin remaining in lungs at the time of sacrifice did not cause strand breaks during sample preparation, bleomycin was added to minced lungin vitro. Under these conditions, the ratio of single‐strand to double‐strand DNA was not increased significantly. Substantial strand breaks were producedin vivoat 15 min and 1 h following intratracheal instillation of bleomycin into hamsters, as evidenced by a 5–6‐fold increase in the ratio of single‐strand to double‐strand DNA relative to controls. The DNA damage appeared to be repaired within 1 day

ISSN:0260-437X    

DOI:10.1002/jat.2550110511

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

Abstract1,4‐Bis(aminocyclohexyl)methane (PACM; CAS No. 1761‐71‐3) is a white solid considered for use in polymeric systems. PACM is moderately toxic systemically, with the acute oral lethal dose in rats between 670 and 1000 mg kg−1. PACM is a weak dermal sensitizer in the guinea pig. Instillation of as little as 10 mg of PACM to the rabbit eye produces severe injury. This damage could be permanent and was not reduced by rinsing the eye with water. Dogs given oral doses of 50 mg PACM kg−15 days per week for up to 18 months showed kidney and liver damage, along with local irritation of the gastrointestinal tract. The chemical is highly irritating and contact with it should b

ISSN:0260-437X    

DOI:10.1002/jat.2550110512

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY