摘要:

The effects of ambient levels of NO2on the spleens of adult and newborn Swiss Webster (S/W) mice were determined. Spleens were evaluated by the following criteria: (1) spleen weight, expressed as a percent of the body weight (% spleen weight), (2) size of the spleen lymphoid nodules as determined by computed image analysis, (3) spleen cell counts, and (4) histopathologic evaluation. Data for NO2‐exposed animals were compared with data for control animals that inhaled filtered air. Totals of 217 control and 217 NO2‐exposed animals were studied. After 6 wk of exposure to NO2at ambient levels (0.35 ± 0.05 ppm), the following significant changes were observed in the spleens of exposed mice: (1) increase in % spleen weight (p <0.0025), (2) increase in size of spleen lymphoid nodules (p <0.01), (3) smaller increase in spleen cell number per given weight increment of spleen as determined by correlation coefficients (p < 0.0125) and linear regression analysis of spleen cell counts, and (4) an apparently greater predominance of red cells in the red pulp. It is concluded that inhalation of N02is associated with quantifiable spleen changes, which may prove to be useful indicators for assessing effects of inhaled NO2.

ISSN:0098-4108    

DOI:10.1080/15287398109530028

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The fate of Inhaled NO2was studied with isolated perfused rat lungs. The isolated lungs were exposed to 5 ppm NO2for 90 min at a ventilation rate of 45 ml/min. The NO2exposure had no adverse effects on the lungs as judged from their weights, glucose uptake, or lactate production compared to control lungs. Isolated lungs absorbed 36% of ventilated NO2, which was detected in perfusate and lung tissue as NO2−but not NO3−. The NO2−concentration in perfusate increased linearly with time, and after 90 min of ventilation with NO2and perfusion with erythrocyte‐free medium the NO2−accumulation was 6.36 ±0.39 μg. If perfusate contained 10% erythrocytes, the ventilated NO2product was mostly NO3−in perfusate but NO2−in lung tissue. Protein solutions absorbed N02more effectively than simple salt solutions, but they all yielded mainly N02−unless erythrocytes were present, when the product was mostly NO3−. The results indicate that absorbed NO2in the lung is converted predominantly to NO2−, but after its diffusion into the vascular space it is oxidized to NO3−by interactions with erythrocytes.

ISSN:0098-4108    

DOI:10.1080/15287398109530029

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Continuous exposure to 2 ppm nitric oxide (NO) for as long as 4 wk did not reduce the resistance of male mice to infection by aerosol inoculation withPasteurella multocida. In contrast, mortality was slightly enhanced and survival shortened in NO‐exposed compared to control female mice; however, the importance of these small differences is uncertain. These results suggest only that male and female mice did not react similarly to the infectious challenge after exposure to NO.

ISSN:0098-4108    

DOI:10.1080/15287398109530030

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Thirty breeding pairs of mallards (Anas platyrhynchos,) were randomly assigned to one of five treatment groups and were fed breeder mash containing 0, 12.5, 50.0, 200.0, or 800.0 ppm Ni (as the sulfate) for 90 d. Ni ingestion had no effect on egg production, hatchability, or survival of ducklings. After 90 d birds were bled, sacrificed, and necropsied. There were no significant differences in hematocrit; concentrations of hemoglobin, plasma triglyceride, and cholesterol; or plasma activities of ornithine carbamoyltransferase and alanine aminotransferase. A black tarry feces was noted in the high Ni dose group at necrospy, but no grass or histopathologic leasions were observed. Although absolute concentrations of Ni in tissues were low, there were significant accumulations in kidneys of birds fed Ni at all dietary levels and in feathers, blood, and livers of birds fed high doses of Ni compared with controls.

ISSN:0098-4108    

DOI:10.1080/15287398109530031

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The possibility that Pb could affect benzene metabolism, through inhibition of enzyme synthesis, was examined by studies of the effects of chronic oral Pb treatments on benzene conversion to phenol. Rats were given either distilled delonized water or 0.05, 0.58, 17, or 352 ppm Pb solutions as drinking water. After 6, 9, 12, and 75 wk of treatment, rats from each group were sacrificed andin vitrobenzene metabolism by benzene hydroxylase was measured in liver enzyme preparations. After 24 wk, the remaining animals were injected ip with 400 mg/kg benzene and urinary phenol levels measured daily for 4 d.

ISSN:0098-4108    

DOI:10.1080/15287398109530032

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

A number of metals were examined for inhibition of a canine renal calcium, magnesium‐activated adenosinetriphosphatase (Ca2+, Mg2+‐ATPose). Of the 27 metals investigated, only compounds of mercury, silver, gold, and uranium demonstrated 50% inhibition of the enzyme at concentrations lower than 10−4M. The order of inhibitory potency was Hg > Ag > U > Au. Organic mercury (chlormerodrin, mersalyl, p‐chloromercuribenzoate) was less potent than inorganic mercuric chloride, but organic gold sodium thiomalate was equipotent with inorganic gold chloride. The inhibition produced by each metal decreased parallel to the decrease in enzyme activity, seen as the source of enzyme moved from the outer cortex inward to the papilla of the kidney. The regions of highest activity showed the greatest inhibition by each metal, and inhibition decreased as the control activity of the tissue decreased. This variability of inhibition was not related to the protein content of the enzyme preparation. As the ATP concentration increased, the inhibition produced by U was reduced; if the Mg (but not the Ca concentration was increased while the ATP concentration remained constant, the inhibition increased. Changes in the Ca, Mg, and ATP concentrations did not alter the inhibition produced by Hg, Ag, and Au.

ISSN:0098-4108    

DOI:10.1080/15287398109530033

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Carcinogenic and other toxic effects in rats and mice were examined during a 12‐mo period following exposure to vinyl chloride (VC) or vinylidene chloride (VDC). Exposure of male and female mice to 50, 250, or 1000 ppm VC for 6 h/d, 5 d/wk, for 1, 3, or 6 mo resulted in increased numbers of deaths and increased moribundity at all dose levels during the exposure and postexposure periods, as compared with air‐exposed controls. Similar observations were made with rats after 1, 3, 6, or 10 mo exposure to VC. Cumulative tumor incidence at various organ sites also increased in both species during the postexposure period in proportion to dose or duration of exposure at higher dose levels. However, except for mammary gland tumors in female mice, no significant increase in cumulative tumor incidence occurred in either species at 50 ppm VC or 55 ppm VDC, regardless of duration of exposure. These results suggest that exposure to vinyl halides at dose levels lower than those that elicit a significant increase in cancer incidence during the lifetime of the animal may, nonetheless, increase the risk of early death or moribundity from toxic pre‐ or sub carcinogenic effects. At dose levels higher than those consistent with the physiological defense or repair capabilities of the cell, ultimate tumor incidence becomes proportionate to length of exposure and may reflect the number of carcinogenic events elicited during the exposure period.

ISSN:0098-4108    

DOI:10.1080/15287398109530034

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Adult female little brown bats (Myotis lucifugus) were collected in a church attic in North East, Cecil County, Md. Mealworms (Tenebrio molitor) containing organo‐chlorine pollutants were fed to the bats as follows: 5 bats were dosed at 480 ppm DDE, 12 at 150 ppm DDE, 5 at 1000 ppm polychlorinated biphenyl (PCB; Aroclor 1260), and 12 at 15 ppm PCB. Seven other bats were fed untreated mealworms. The objective was to elevate brain levels of DDE and PCB to lethality and measure these concentrations. During 40 d of dosage, one DDE‐dosed bat and two PCB‐dosed bats died after exhibiting the prolonged tremoring that characterizes organochlorine poisoning. After dosage, surviving bats were starved to elevate brain levels of toxicants, and three additional DDE‐dosed bats tremored before dying.

ISSN:0098-4108    

DOI:10.1080/15287398109530035

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Japanese quail (n=32), dosed orally with acrylamide monomer, showed an LD50 (95% confidence interval) of 214 mg/kg (194–236) at d 1 after dosing and of 186 mg/kg (171–202) at d 4 and 7 after dosing. Effects on righting and on posture and gait were prominent neurological signs. Wing strength and tone were less affected. Recovery was suggested in both neurological signs and body weights.

ISSN:0098-4108    

DOI:10.1080/15287398109530036

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Larval white perch were subjected to interacting power plant conditions of total residual chlorine (0.00–0.30 mg/l), elevated temperature (2, 6, and 10°C), and exposure time (0.08, 2.0, and 4.0 h) at acclimation temperatures of 15 and 23°C. Mortality observations were conducted up to 96 h after exposure. Acclimation temperature was a significant factor contributing to the effects of simulated power plant conditions during the low and high thermal conditions. Larvae tested at 23°C generally showed greater mortality at all treatment levels than those tested at 15°C. Mortality of test organisms during a 4‐h exposure at the higher acclimation temperature was greater than 85% at elevated temperatures greater than 6°C regardless of other treatment factors. Mortalities as low as 30% were observed at the lower acclimation temperature.

ISSN:0098-4108    

DOI:10.1080/15287398109530037

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor