Body weight ratio

A significant increase in heart-to-body-weight ratio occurred in female rats exposed to 2.5 mg/kg/day methyl parathion in the diet for 2 years, but not in rats exposed to either 0.025 or 0.25 mg/kg/day methyl... 

An increased ratio of T suppressor cells to T helper cells was seen in mice given 2.5 and 5.0 mg/kg/day of methyl parathion for 15 days the spleen to body weight ratio was increased at 5 mg/kg/day (Tian et al. 1997). No other immunological or lymphoreticular end points were measured. 

Seasonal Study of Mixed Function Oxidases.— A seasonal study of hepatic microsomal mfo components has been conducted in female R and S fish (submitted for publication). Components studied were cytochromes P-450 and 5, NADPH-cytochrome c reductase, NADPH-dichlorophenolindophenol reductase, NADH-cytochrome c reductase and NADH-cytochrome 5 reductase. All were monitored at 30°C by standard spectrophotometric methods following optimization procedures (8, 9 > 10, n, J 2). Microsomal and total hepatic protein (137 and liver weight to body weight ratios were also monitored. 

Figure 3. Liver weight to body weight ratios (LW X 100/BW) in insecticide-resistant and -susceptible mosquitofish...

Cardiovascular Effects. No studies were located regarding cardiovascular effects in humans after oral exposure to heptachlor or heptachlor epoxide. In an intermediate-duration study, increased heart-to-body-weight ratio was reported in rats following dietary exposure to 0.5 mg/kg/day heptachlor, 5 days/week, for 4 weeks (Enan et al. 1982). 

Oral exposure of mice to heptachlor for 92 days (10 mg/kg/day) or 180 days (5.7 mg/kg/day) increased SGPT and decreased phospholipids and total serum cholesterol (Izushi and Ogata 1990). Triglyceride content was increased at 92 days only. Evidence of liver damage was seen as a significant increase in SGPT. An increase in the liver-to-body-weight ratio was also observed. 

Infants and toddlers are exposed to higher levels (based on their greater dose to surface area [or body weight] ratio) of heptachlor epoxide in the diet (particularly from milk) than are adults. Higher exposure rates in indoor air may occur for at least 1 year in homes that have been treated for termites with heptachlor in the past. Although the most likely routes of exposure at hazardous waste sites are unknown, exposure may result from ingestion of contaminated soil near these sites particularly by children. Since both heptachlor and heptachlor epoxide volatilize from soil, inhalation exposure may also be important for persons living near hazardous waste sites. Exposure via... 

Current concern regarding TCA arises from chronic low-level exposure via chlorinated drinking water. In 90-day subchronic studies, 5000 ppm in the drinking water caused increased liver- and kidney-to-body weight ratios in rats. Increased hepatic peroxisome activity and histopathologic changes in the liver and kidneys were also observed. 

Children Children may be more susceptible to topical corticosteroid-induced hypothalamic-pituitary-adrenal (HPA) axis suppression and Cushing syndrome than adults because of a larger skin surface area to body weight ratio. 

Liver/body weight ratio Increased Increased Slightly increased... 

Male and female Fischer 344 rats (six weeks of age) and B6C3Fi mice (seven to nine weeks of age) and New Zealand White rabbits were exposed by inhalation to 0, 99, 382 or 782 ppm [0, 0.43, 1.66 or 3.40 g/m ] ethylbenzene and 0, 382, 782 or 1610 ppm [0, 1.66, 3.40 or 6.99 g/m ] ethylbenzene, respectively, for 6 h per day on five days per week for four weeks. At 782 ppm, both rats and mice exhibited an increase in mean liver weight and liver-to-body weight ratio. There were no alterations in clinical chemistry, urinalysis or gross or microscopic changes in any of the species tested that were attributable to exposure to ethylbenzene. The authors noted that the... 

In another study of intermediate-duration, Fischer 344 rats were exposed to 0, 0.011, 0.041, or 0.143 ppm HDI in air 6 hours per day for 66-69 days over a period of approximately 13 weeks. Animals were exposed to HDI in 2-cubic-meter chambers (whole body). All rats were sacrificed during week 14. No compound-related toxic effects were noted by changes in liver weights or liver weight to body weight ratios at gross necropsy (Mobay Corporation 1988). 

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