ISSN:0260-437X    

DOI:10.1002/jat.2550080602

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

ISSN:0260-437X    

DOI:10.1002/jat.2550080603

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractProtection from carbon tetrachloride (CCl4)‐induced hepatotoxicity by protein A was assessed histologically in rats. Carbon tetrachloride exposure produced swollen, vacuolated and necrotic cells in the centrilobular region of the hepatocyte in rats. Animals given protein A prior to and during CCl4treatment showed a complete absence of hepatic lesions. Our study showed that protein A, a potent immunomodulator, has the potential to reduce liver injury caused by carbon tetrachloride, a known hepatotoxin in the ra

ISSN:0260-437X    

DOI:10.1002/jat.2550080604

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractRats receiving a single oral dose of 286.8 μmol/kg tris(2,3‐dibromopropyl)phosphate (Tris‐BP) showed pyknosis of the renal tubular epithelial cells on Day 1, necrosis on Day 2, regeneration from Day 3 and large nuclei formation from Day 4.13C‐NMR spectra were applied to clarify changes of the renal low‐molecular‐weight components in the kidney injured by Tris‐BP, and sialic acid and inositol were found as the desired marker components. The lesions produced by Tris‐BP were characterized by changes in the renal components and enzyme activities. Increases in sialic acid content of the kidney were observed both on Day 1, suggesting destruction of the epithelial cell membrane, and on Day 5, suggesting regeneration accompanied by an increase of inositol content on Days 7 and 10. Renal activity of cytoplasmic enzyme, alanine aminopeptidase, was decreased on Days 1 and 5 and elevated on Days 7 and 10. Lactate dehydrogenase activity showed a tendency to decrease in the kidneys on Day 1 and to increase significantly on Days

ISSN:0260-437X    

DOI:10.1002/jat.2550080605

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractThis paper deals with the conversion of the hepatotoxicity of 1,2‐dichlorobenzene (DCB), the nephrotoxicity of hexachloro‐1,3‐butadiene (HCBD) and the respiratory effects of these two toxicants into quantal data. It aims to provide some useful information on the best strategy used for safety evaluation. A reflex bradypnea indicative of irritation of the nasal cavities of mice occurred during a 15‐min oronasal exposure to each chemical. A reduction in the development of staining for liver glucose‐6‐phosphatase (G6‐phosphatase) and an increase in the number of damaged tubules in cryostat kidney sections stained for alkaline phosphatase were the measure of toxicity in mice subjected to a whole‐body 4‐h exposure to DCB and HCBD vapours, respectively. The immediate irritant responses, as well as the delayed liver and kidney responses, were measured at the peak of the chemical's action. These maximum responses were then used to establish the relationships of exposure level effects and also the median active levels of exposure (MALs). The DCB and HCBD MALs responsible for a 50% decrease in the respiratory rate of mice (RD50) were 181 and 211 ppm, respectively. The MAL required for eliciting a 50% decrease in G6‐phosphatase staining intensity in DCB‐exposed mice was 598 ppm and that associated with 50% of damaged tubules in HCBD‐exposed mice was 7.2 ppm. On the basis of these quantitative data, potency ratios indicated that irritation and kidney injury are the primary manifestations of toxicity associated with short‐term exposure to DCB and HCBD, respectively. It is suggested that profiles of acute toxicity similar to that of DCB or HCBD may be useful in assessing the relative hazard involve

ISSN:0260-437X    

DOI:10.1002/jat.2550080606

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractA protocol to provide a more rapid assessment of the fibrogenic potential of an inhaled particulate has been developed. Young rats are exposed nose‐only for 6 h/day, 7 days a week for 28 days to a respirable aerosol of the test compound. After exposure the rats are kept for up to 1 year, followed by histopathological assessment of the lung. Interim sacrifices could allow an estimate of the rate and severity of the development of any fibrogenic lesion.The protocol has been evaluated for chrysotile asbestos, α‐quartz and titanium dioxide using rats of both sexes and two different ages at first exposure. The results indicate that there are no significant differences in either the rate, type or extent of lesion provoked by a 28‐day exposure period when compared with the more conventional 1‐year exposure period studies. It can be concluded that neither sex nor age at first exposure cause any biologically significant differences in response, although young rats would be used in practice. Only one sex need be investigated.The protocol offers considerable benefits over conventional inhalation studies for fibrogenicity (where a 1‐year exposure period followed by a further 1‐year holding period is usual) by virtue of time, specificity (in the absence of continued exposure the development of any lesion can be studied free from initial inflammatory response) and cost, and could be incorporated into a standard subacute inhalation study design.The results obtained are also of more physiological relevance than studies based on intratracheal

ISSN:0260-437X    

DOI:10.1002/jat.2550080607

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractSpray‐can ingredients, if liberated in confined spaces, are potential health hazards for man. Thus, appropriate inhalation toxicity studies have to be performed in accordance with internationally recognized guidelines, e.g. the US Environmental Protection Agency: Federal Insecticide, Fungicide and Rodenticide Act (FIFRA no. 81–3) or OECD no. 403.One of the essential requirements of such guidelines is that test animals (preferably rats) be exposed to a steady‐state concentration in a dynamic inhalation chamber for at least 4 hours. This is not easy to achieve with vapours released from a pressurized spray‐can.The method described here makes it possible to expose experimental animals in an inhalation chamber to a steady‐state concentration of intermittently released spray jets of constant doses per jet. Animal experiments and theoretical considerations (computer simulations) have shown that the method presented allows an up‐to‐date determination of the acute inhalation toxicity of spray‐

ISSN:0260-437X    

DOI:10.1002/jat.2550080608

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

摘要:

AbstractThe effect of increasing the time interval between vanadium exposure and chelation therapy was studied in male Swiss mice. The following chelating or reducing agents were administered i.p. at 0, 0.5, 2 and 8 h after i.p. administration of 0.16 mmol kg−1sodium metavanadate: ascorbic acid, deferoxamine mesylate (DFOA) and 4,5‐dihydroxy‐1,3‐benzene‐disulphonic acid (Tiron). These agents were given at doses equal to one‐quarter of their respective LD50values. Daily elimination of vanadium into urine and faeces was determined for four days. The excretion of vanadium was especially rapid in the first 24 h. Treatment with Tiron increased significantly the urinary elimination of vanadium in all four groups during Day 1, whereas DFOA significantly increased the faecal excretion during the same period. Treatment with DFOA or Tiron resulted in a significant decrease in the concentration of vanadium in the kidney four days after sodium metavanadate administration. The magnitude of the increased elimination of vanadium, as well as the decreased tissue concentration of the metal, was remarkably attenuated by increasing the time interval between vanadium injection and administration of th

ISSN:0260-437X    

DOI:10.1002/jat.2550080609

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

ISSN:0260-437X    

DOI:10.1002/jat.2550080611

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY

ISSN:0260-437X    

DOI:10.1002/jat.2550080613

出版商:John Wiley&Sons, Ltd.    

年代:1988

数据来源: WILEY