The effects of ethylene chlorohydrin on fatty acid synthesis

Male chicks weighing 700 to 900 g. received an acute or eight doses IG of 60 or 40 mg/kg ethylene chlorohydrin (ECH) respectively and were sacrificed eighteen hours after the last dose. Mitochondrial elongation of fatty acids was decreased significantly while fatty acid synthetase activity was not significantly affected by ECH treatment. Cytochrome c oxidase activity in fresh whole liver homogenate was significantly higher in chicks subjected to acute exposure with ECH when compared to the controls. Upon freezing and thawing of homogenates, cytochrome c oxidase activity increased significantly in the control group but was unchanged in the ECH group which suggests that the mitochondrial membrane integrity is compromised by the ECH treatment. Serum and liver triglyceride levels were significantly elevated in both the single and multiple ECH dose groups. Liver to body weight ratios were significantly higher in both treatment groups when compared to their controls. Histological examination of the liver of ECH-treated chicks showed cytoplasmic clearing of the cells but no vacuolization or centrilobular necrosis. Serum isocitrate dehydrogenase levels were significantly higher in the multiple treatment ECH group than in the control group.     

Fertility of female mice fed coumestrol and diethylstilbestrol

Coumestrol, a compound produced by various legumes which exerts estrogen-like activity in animals, and diethylstilbestrol (DES) were studied as chemical agents for controlling reproduction in mice. Female mice were fed control diets or diets containing 100 ppm coumestrol for eight days. Female mice were exposed to males and reproductive tracts examined 14 days later. Litter size was not affected by 100 ppm dietary coumestrol but feed consumption was reduced 17%. Similar trials were conducted with mice fed 1 ppm DES. Vaginal plugs were present in 50% of the females fed 1 ppm DES, but no fetal pups were present. Feed intake was reduced 37% by the DES. Levels of 0, .1, .25, .50, .75 and 1.0 ppm DES were compared in two strains of mice, Swiss and ICR. Reproduction in both strains was totally inhibited by all DES treatments. The use of DES to control rodent populations warrants further investigation.     

The economics of bauxite and aluminium: Distributed lags and new econometric estimates

Bauxite supply and demand equations for the largest producers and consumers are estimated with 1958–1982 data. In specifications that include industrial activity indexes, substitute prices and energy costs, these regressors improve the fits and are statistically significant. The own price variable, the Koyck-Nerlove lagged dependent variable, or both, become insignificant, or their estimated coefficients are substantially altered, in relation to their values in price-only models, which overestimate the own price impact and the gap between long- and short-term effects. Industrial activity is the main determinant, followed by the other new regressors. The Jamaican response to price is perverse and significant.     

Zearalenone metabolism and excretion in the rat: effect of different doses

Young female rats were orally dosed with either 1 or 100 mg zearalenone kg-1 body weight; zearalenone and metabolites were measured in a 96-h collection of urine and feces by HPLC analysis. Dose had little effect on metabolites formed, or excretion route. In both treatment groups, about 55% of the oral dose was excreted in the feces, while the urine was also a major route of excretion accounting for 15-20% of the administered dose. Zearalenone and metabolites were excreted mainly in the free form, with the production of alpha-zearalenol, the most potent estrogenic metabolite, being greater than 10% of the zearalenone dose.     

Detection of pentachlorophenol and its glucuronide and sulfate conjugates in fish bile and exposure water

The glucuronide and sulfate conjugates of pentachlorophenol (PCP) that were present in the bile and exposure water of goldfish (Carassius auratus) were used to develop methodology to quantify PCP and its metabolites. Reverse phase HPLC with radioactivity detection separated PCP and its metabolites, and was used to verify a method of quantification that used differential extraction and scintillation counting. Extractions of aqueous phase at pH 2 or 8, with butanol, ethyl acetate, or ether indicated that ether at pH 8 best separated PCP from its metabolites. The sulfate conjugate of PCP was the major metabolite produced when goldfish were exposed to 125 micrograms 14C-PCP/l. It was present primarily in the exposure water, but also appeared in the bile.     

The empirical modeling of an ecosystem

The authors have endeavored to create a verified a-posteriori model of a planktonic ecosystem. Verification of an empirically derived set of first-order, quadratic differential equations proved elusive due to the sensitivity of the model system to changes in initial conditions. Efforts to verify a similarly derived set of linear differential equations were more encouraging, yielding reasonable behavior for half of the ten ecosystem compartments modeled. The well-behaved species models gave indications as to the rate-controlling process in the ecosystem.     

Teratogenic evaluation and fetal deposition of hexabromobenzene (HBB) and hexafluorobenzene (HFB) in CD-1 mice

HBB (hexabromobenzene) and HFB (hexafluorobenzene) were tested for their teratogenic potential in CD-1 mice. HBB and HFB were administered to pregnant mice from the 6th to the 16th day of gestation by gastric intubation. Neither HBB nor HFB were teratogenic or fetotoxic at doses up to 98.6 mg HBB/kg and 65.3 mg HFB/kg. No maternal toxicity was noted. HBB concentration in the fetuses indicated little, if any accumulation. No HFB was detected in the fetal or maternal tissues 24 hours after the last dose.     

The classroom setting as a source of expectations about teachers and pupils

The major purpose of this research is to examine the impact of classroom spatial arrangement (open versus traditional) and orderliness (messy versus neat) on observers' impressions of teachers and pupils. In experiments 1 and 2, samples of college students were shown color slides of vacant elementary classrooms which varied on these two physical dimensions. Subjects were asked to indicate their impressions of the teacher and the pupils who used each room by completing a set of bipolar adjective scales. Data analysis indicated that teachers in neat classrooms were rated more positively than their counterparts in disorderly classrooms on measures of kindliness, inventiveness, and organization. Pupils associated with neat classrooms were judged to be happier and better behaved. Open classroom teachers received higher ratings than traditional classroom teachers on kindliness and inventiveness. In experiment 3, the same procedure was used to obtain ratings from fifth-grade students. Their judgements of teacher and pupil characteristics were also positively affected by neatness, but classroom arrangement had no impact.     

Absorption and metabolism of the chiral isomers of fonofos in the corn and cotton plant

Root absorption of chiral phenyl-35S-fonofos in cotton and corn plants revealed stereoselective differences between the two enantiomers. (S)p-Fonofos was absorbed at a faster initial rate and to a greater extent than the (R)p enantiomer in both plant species. Approximately 40% and 62% of the applied radioactivity was absorbed into the cotton plant 12 hr after application of (R)p- and (S)p-fonofos, respectively. In the corn plant, approximately 25% and 63% of the applied (R)p- and (S)p-fonofos was absorbed in the first 12 hrs. Little qualitative or quantitative difference in plant translocation between fonofos enantiomers was observed. (R)p-fonofos was found to be metabolized to a greater extent than the (S)p enantiomer in both cotton and corn plants.