摘要:

AbstractThis study was conducted to determine if significant differences in phagocytosis occurred in pulmonary alveolar macrophages in suspension or monolayer cultures. Dog alveolar macrophages were incubated with different numbers of fluorescent polystyrene latex microspheres, both in suspension and in monolayer cultures. The particle uptake by cells was linear for 10–100 min and the fraction of cells that contained particles was similar for both incubation techniques. Differences between carboxylated and non‐carboxylated microspheres were statistically not significant. The overall particle numbers associated with cells were 2–5 times higher for cells incubated in suspension compared to adherent cells. Many more cells were found with low particle numbers at all incubation times using the monolayer technique compared to the suspension technique. When cells were treated with xylene for 1 h after different times of incubationin vitro, a higher decrease in particle numbers in cells was found in suspension cultures than in monolayer cultures. This finding suggests higher particle binding when cells were incubated in suspension, but particle numbers after xylene treatment were still higher in cells incubated in suspension than in monolayers. A comparison with the uptake of similar particles by dog alveolar macrophagesin vivosuggests that the suspension cultures were more similar to the events in the dog lung, but uptake rates were about a factor of two lower with suspended cells than those seenin

ISSN:0260-437X    

DOI:10.1002/jat.2550090302

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractReports of respiratory problems among industrial workers exposed repeatedly by inhalation to azodicarbonamide (ADA) raised concern that ADA might be a pulmonary sensitizer. We used a non‐invasive method for measuring specific airway conductance to evaluate the potential for repeated inhalation of unconjugated ADA to cause specific or non‐specific pulmonary sensitization in the guinea pig. Two groups of male Hartley guinea pigs were exposed 6 h/day, 5 days/week for 4 weeks to aerosolized ADA at 51 or 200 mg/m3, or to filtered air as controls. One group was tested for specific sensitization to ADA by measuring specific airway conductance during inhalation challenge with ADA before and on the third day after the 4‐week ADA exposure. The ADA concentrations for the challenges were identical to the repeated exposure concentrations (51 or 200 mg/m3, 200 mg/m3for controls). The other group was tested for non‐specific airway sensitization by inhalation challenge with aerosolized histamine before and after the 4‐week ADA exposure. Histamine was administered in stepwise increasing concentrations to elicit an airway response in each guinea pig. Skin tests for immunological responses to ADA, body weight and histopathology of the respiratory tract and skin test sites were also evaluated. The 4‐week exposure to ADA did not result in either specific or non‐specific airway sensitization. The ADA exposure did not induce positive skin reactions, influence body weight or cause histopathological responses. These results indicate that ADA, acting alone (i.e. not conjugated to a protein), is not a pulmonary sensitizer in the guinea pig exposed repeatedly for 4 weeks and challenged to simulate a ‘Monday mo

ISSN:0260-437X    

DOI:10.1002/jat.2550090303

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe effects of acetaldehyde and ethanol treatments on hepatic lipid peroxidation are compared in rats after the administration of toxically corresponding doses. Wistar rats were given a single dose of acetaldehyde (0.5 g/kg) or ethanol (5 g/kg) intraperitoneally. The animals were killed 1/2, 1, 2, 4, 6, 9, 12 and 24 h after treatments. The results indicate that acetaldehyde, like ethanol, stimulates hepatic lipid peroxidation and also selectively affects the hepatic mitochondria.

ISSN:0260-437X    

DOI:10.1002/jat.2550090304

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractDiesel exhaust particles are known to contain mutagenic and carcinogenic chemicals. The aim of this study was to determine whether, and to what extent, catalytic particulate trap oxidizers on light‐duty diesel engines may reduce the emission of particle‐associated mutagenic chemicals into the environment. Exhaust particles were collected from Mercedes Benz and Volkswagen diesel automobiles, equipped with or without the manufacturer's exhaust traps, while running on a chassis dynamometer under specified load conditions. Exhaust particles were collected from a dilution tunnel onto 20″ × 20″ Teflon®‐coated fiberglass filters. Mutagenesis tests of dichloromethane (DCM) extracts of the particles were conducted using the AmesSalmonellabacterial test system. The mutation rate was calculated in terms of histidine revertants per mile of travel during a set of standard test cycles. With both vehicles the traps produced an 87–92% reduction in the total amount of particulate material collected by the filters. There was no significant change in the specific mutagenic activity (revertants per microgram of DCM particle extract) with or without the traps. These studies support the notion that installation of exhaust traps which reduce particulate emission on diesel‐powered vehicles will also reduce the emission of particle‐associated mutagenic and carcinogenic materials int

ISSN:0260-437X    

DOI:10.1002/jat.2550090305

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractDifferent scavengers of active oxygen species (superoxide dismutase, catalase, mannitol and dimethylfuran) were tested in the AmesSalmonellaassay to determine the role of the reactive oxygen species in the benzo[a]pyrene (B[a]P) mutagenesis process. Exogenously added superoxide dismutase or catalase at 10–100 μg ml−1top agar, or 3–12 mM mannitol showed no effect on B[a]P mutagenicity in the presence of S9 mix. However, dimethylfuran (DMF), a singlet oxygen scavenger, inhibited in a dose‐related manner the mutagenic response of B[a]P in the presence of the microsomal fraction. DMF at 3 and 6 mM inhibited the number of revertants by 69 and 93% for strain TA 100, and 76 and 78% for TA 98, respectively. DMF at these levels was neither toxic nor mutagenic to the bacteria. The result indicates that singlet oxygen may play an important role in promoting B[a]P muta

ISSN:0260-437X    

DOI:10.1002/jat.2550090306

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractFeeding soy protein concentrate to weanling rats over a one‐week period produced a dose‐related increase in pancreatic weight due to an increase in acinar cell size. Hyperplastic changes occur simultaneously, as evidenced by an increase in mitotic activity after two days on the test diet. Similar changes were also obtained by feeding soybean Kunitz trypsin inhibitor over the same time period. The results suggest that this approach may be useful as a model to investigate the effect of plant‐derived material on the pancreas, in particular proliferative le

ISSN:0260-437X    

DOI:10.1002/jat.2550090307

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractMale NMRI mice were treated i.p. with dichlorovinylcysteine (DCVC) in a dosage of 2.5‐500 mg/kg−1and renal cortical slices from naive mice were incubated with 0–125 μg/ml−1DCVC. The effects of DCVC on blood urea nitrogen (BUN), reduced glutathione (GSH) content, malondialdehyde (MDA) production,p‐aminohippuric acid (PAH)‐ and tetraethylammoniun (TEA)‐accumulation and glucose synthesis (gluconeogenesis) were measured.DCVC depleted GSH in a time‐ and dose‐dependent manner. Depletion of renal cortical GSH by DCVC was more pronounced in the kidney cortex than in the liver. DCVC caused a dose‐dependent increase of ethane exhalation and of MDA production in the renal cortex. When animals were kept in a closed system, decrease in oxygen concentration increased the peroxidative damage. No increase of MDA concentration was observed in the liver. Treatment of mice with DCVC induced a dose‐dependent increase in BUN and decreased the accumulation of PAH and TEA in renal cortical slices. Pretreatment of mice with aminooxyacetic acid (AOAA) and (+) cyanidanol‐3 (CY) caused a significant reduction in DCVC‐induced lipid peroxidation and nephrotoxicity.In vitroincubation of renal cortical slices of naive mice with DCVC resulted in a concentration‐dependent increase in MDA and a concentration‐dependent decrease in the accumulations of PAH, TEA and of gluconeogenesis.In conclusion, the interaction of DCVC and/or its metabolites with membrane lipids may be responsible for lipid peroxidation and nephrotoxicity. The formation of lipid peroxidation products was greater under hypoxic conditions and appeared to be related to the DCVC‐induced nephrotoxicity. This data suggests lipid peroxidation as a possible mechanis

ISSN:0260-437X    

DOI:10.1002/jat.2550090308

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe teratogenicity ofN‐cyclohexyl‐2‐benzothiazylsulfenamide (CBS) was studied in Wistar rats. Pregnant rats were given CBS at a dosage of 0.001, 0.01, 0.1 or 0.5% in the diet from Day 0 to Day 20 of pregnancy. Daily intakes of CBS were 0.7 mg kg−1for the 0.001% group, 7.1 mg kg−1for the 0.01% group, 69.6 mg kg−1for the 0.1% group and 288.8 mg kg−1for the 0.5% group. Maternal body weight gain during pregnancy in the 0.1 and 0.5% groups was significantly lowered. Food consumption during pregnancy in the CBS‐treated groups, except for the 0.5% group, did not differ from that in the control group. Neither death nor clinical signs of toxicity were noted in the pregnant females of any group. Lowered weight in fetuses and the placentae were observed in the 0.5% group. There were no significant compound‐related effects on the incidences of pre‐ and post‐implantation losses and the number and ratio of live fetuses. Morphological examinations of the fetuses revealed no evidence of teratogenesis. It could be concluded that CBS possesses no adverse effects on the prenatal development of the offspring in rats at doses employed

ISSN:0260-437X    

DOI:10.1002/jat.2550090309

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractAdverse effects, involving a combination of hypotension and widespread haemorrhages, as well as evidence of vascuiiar and other tissue dissociation, associated with various systemic malfunctions (cyanosis, cardiac arrhythmias, neuromuscular disorder and death) were observed in the rat, from parenteral administration of a high‐molecular‐weight soluble polymer, sodium polyacrylate (EN21). Experiments to elucidate the mechanism of this effect involved comparisons with a low‐molecular‐weight sodium polyacrylate (EN5), either drug being given to groups of 5–8 rats, male or female, in doses of 5–100 mg/kg i.v., i.p. or s.c., or up to 100 mg/kg p.o. Effects were observed visually up to the death of the animals, and these plus survivors killed after 10 h were prosected for macroscopic and histopathological examination of internal organs. Characteristic EN21 effects were only observed in animals treated by the i.p. and i.v. routes, death occurring in 4–10 h or rapidly (1 h) after i.v. dosage. No such effects were observed from ENS by any dose or route. There were no differences between effects in male and female animals.In rats anaesthetized with sodium pentobarbitone and cannulated for blood pressure recording (arterial and venous), no hypertensive effects were observed to explain haemorrhagic effects. Instead, i.v. and i.p. injections gave depressor effects, insidious in the latter case, with a precipitous fall only in the delayed terminal stage. Effects were accompanied by cardiac arrhythmias. Depressor effects were prevented by prior treatment of the animals with calcium chloride solution. These effects could not be evoked by EN5, nor by injection of methylcellulose solutions of equivalent high viscosity. It is suggested that, in the absence of pressor effects, haemorrhages must be explained by vascular fragility (angiostaxis), associated with disintegration of other tissues (e.g. intestinal villi). Other malfunctions, too rapid to be dependent on loss of blood, could be explained in terms of hypocalcaemia.It is suggested that localization of this viscous, high‐molecular‐weight material in vascularized compartments, together with its known ability to form insoluble precipitates with calcium, leads to the operation of a calcium ‘sink’. Resulting hypocalcaemia would explain neuromuscular and cardiac malfunctions, while radical loss of tissue calcium could lead to decrease in cellular adhesion. Resultant loss of tissue integrity could be consistent with observed haemorrhage and d

ISSN:0260-437X    

DOI:10.1002/jat.2550090310

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

ISSN:0260-437X    

DOI:10.1002/jat.2550090311

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY