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Biomedical subjects

H C Cecil

Publications and source records attributed to H C Cecil.

At least 37 records · Page 2Linked to original sources
PubMed1978

Liver mixed function oxidases in chickens: induction by polychlorinated biphenyls and lack of induction by DDT.

Microsomal hydroxylase and demethylase activities were compared in livers from White Leghorn cockerels fed polychlorinated biphenyls (PCBs) containing 21 to 68% chlorine, or p,p'-DDT. The higher chlorinated PCBs, Aroclor 1254 and 1268, were potent inducers of hepatic enzyme activity while DDT did not induce these enzymes. Aroclor 1254 was the most potent inducer because feeding 5 ppm increased liver aminopyrine demethylase activity 1.5X but did not affect liver weight. Feeding 50 and 500 ppm of Aroclor 1254 and 1268 increased liver weight and demethylase activity per mg of protein. A differential response in the two enzymes occurred. Only 500 ppm of Aroclor 1268 increased hydroxylase activity. Aroclor 1242 had no effect on liver enzyme concentration but 50 and 500 ppm of Aroclor 1242 increased liver weights and consequently increased total enzyme activity. Our data demonstrated that in the avian species DDT and PCB did not have the same effect on hepatic microsomal enzyme activity.

Aniline Hydroxylase↗
PubMed1978

Embryotoxic effects of polybrominated biphenyls (PBB) in rats.

Pregnant Sprague Dawley rats were given 0, 0.25, 0.5, 1, 5, and 10 mg of a commercial polybrominated biphenyl, FireMaster BP-6 (PBB), in olive oil by gavage each day from days 7 through 15 of pregnancy. Laboratory chow and water were given ad libitum. Treatment with PBB had no significant effect on body weight gain, food and water consumption, and urine production. The mothers were killed on day 20, and the only significant effect observed was an increased liver weight of those given 1, 5, and 10 mg PBB. Spleen, kidney, ovarian, gravid uterine, and perirenal fat pad weights were similar to those of control mothers. PBB had no significant effect on number of live/dead fetuses, crown-rump length or fetal weight. No grossly malformed fetuses were observed in PBB-treated mothers. The effects of PBB transfer from mothers to nursing pups was studied by reciprocal exchange of pups between control mothers and mothers treated with 10 mg PBB. When the pups were 21 days old, they were weaned and fed control chow. The following four combinations of prenatal-postnatal exposure were studied: control-control (C:C); control-PBB (C:PBB); PBB-control (PBB:C); and PBB-PBB. Although the birth weights of pups from PBB-treated mothers were similar to those of the controls, body weights of 60-day-old males exposed prenatally and postnatally (PBB:C, C:PBB, and PBB:PBB) were less (p less than 0.05) than those of the controls (C:C). The weights of the perirenal fat pads of male and female pups exposed to PBB were less (p less than 0.05) than the control. Liver weights, on a body weight basis, were higher in male and female pups exposed to PBB. Vaginal openings were delayed; the percentages of 36-day-old pups with open vaginas were 50 (C:C), 38 (PBB:C), 28 (C:PBB), and 30 (PBB:PBB).

Animals↗
PubMed1977

Retention and excretion of polychlorinated biphenyl residues by laying hens.

Commercial polychlorinated biphenyl (PCB) mixtures with 21, 32, 42, 48, 54, and 68% chlorine were fed to caged White Leghorn hens at 20 p.p.m. for nine weeks. The 42, 48, and 54% mixtures were also fed at 2 p.p.m. Residues in egg at nine weeks were 0.7, 2.4, 14.4, 9.3, 11.4, and at 21.5 p.p.m. for the 21, 32, 42, 48, 54, and 68% chlorine PCBs, respectively. Corresponding values in body fat were 24.0, 51.1, 89.3, 90.5, 124.5, and 52.4 p.p.m., respectively. Levels in eggs and body fat of groups fed 2 p.p.m. were approximately one-tenth the levels in the 20 p.p.m. group. After seven weeks of control feed, the values for the 20 p.p.m. groups were 0.7, 1.8, 2.8, 3.0, 7.2, and 1.8 for eggs and 8.1, 22.4, 26.4, 39.8, 91.7, and 43.6 for body fat. Estimated recovery of consumed PCBs increased from 8% to 55% as chlorine increased from 21 to 68%. Residues in excreta was about 10% of intake for all PCBs. Body fat retention was greater than egg elimination for 21 through 48% chlorine PCB, about the same for 54% and much less for the 68% chlorine PCB. The ratio of egg: fat residue in contaminated birds was .084:1.

Adipose Tissue↗
PubMed1975

Effects of polychlorinated biphenyls and terphenyls and polybrominated biphenyls on pentobarbital sleeping times of Japanese quail.

Polychlorinated biphenyls (Aroclor 1221, 1232, 1242, 1248, 1254, 1260, 1262, and 1268), polychlorinated terphenyls (Aroclor 5460), a mixture of polychlorinated biphenyls and terphenyls (Aroclor 4465) and polybrominated biphenyls (BP-6) were administered in a single dose, 100 mg/kg body weight injected orally, to mature male and female Japanese quail. Two hr after Aroclor treatment, pentobarbital sleeping times were prolonged (2 to 3 times control) in both male and female quail. Twenty-four hr after treatment, sleeping times were similar to those of controls. However, 48 hr after treatment with Aroclor 1248 through Arolcor 5460 and with BP-6, sleeping times of males were only 1/2 those of controls, whereas after treatment with Aroclor 1221, 1232 and 1242, sleeping times were similar to those of controls. The reduction in sleeping times of male quail 48 hr after administration of PCBs was correlated with the percentage of chlorine in the PCB with greater reductions in male than female quail. The response after three days ad libitum feeding of 300 ppm of each substance was the same as the response 48 hr after a single oral injection. Although very few birds died from the toxicity of the Aroclors and BP-6, mortality was greatly increased during anesthesia when the pentobarbital was administered two hr after single oral dosing.

Animals↗
PubMed1975

Toxicity of certain polychlorinated and polybrominated biphenyls on reproductive efficiency of caged chickens.

The biphenyls tested with caged White Leghorn pullets were polychlorinated biphenyl (PCBs) Aroclors 1232, 1242, 1248, 1254 and 1016 and polybrominated biphenyl (PBB) PBP-6 at the 5, 10 and 20 p.p.m. levels. These pollutants exerted no adverse effects on egg production, egg weight, egg shell thickness, feed consumption, adult body weight changes, livability and fertility after 8 weeks of biphenyl feeding, irrespective of biphenyl level or compound. Hatchability of fertile eggs as a result of biphenyl feeding was significantly affected by 10 or 20 p.p.m. and by three PCB compounds (Aroclors 1232, 1242, 1248). The hatchability (%) of eggs laid by pullets fed 10 and 20 p.p.m. declined to 78 and 45, respectively, for Aroclor 1232, 48 and 5 for Aroclor 1242 and 40 and 5 for Aroclor 1248 after 6 weeks of biphenyl feeding, as compared with 90 for the control group. The most common embryonic abnormality was edema in the neck and rump areas. Biphenyl supplementation in the maternal diet also caused a shift in the peak pattern of embryonic death. Progeny growth as a result of biphenyl in the maternal diet was significantly depressed by 10 or 20 p.p.m. and by Aroclors 1242 and 1248. The level of the three PCBs found to be toxic to chickens appears to lie somewhere between 5 and 10 p.p.m.

Animals↗