Ryland E. Webb

Endrin Resistance in the Pine Mouse

Wild pine mice with a history of treatment with endrin exhibited a 12-fold greater tolerance to the pesticide than did mice having no history of endrin treatment. A genetic basis for the resistance would be expected, in view of the fact that the resistant mice had been exposed to endrin for 11 years. However, sublethal dosages conferred a degree of resistance on both mouse populations; this indicates the possibility of an inducible resistance.

Relationship of Diet-Health Attitudes and Nutrition Knowledge of Household Meal Planners to the Fat and Fiber Intakes of Meal Planners and Preschoolers

Abstract The relationship of household meal planners’ diet-health attitudes and nutrition knowledge to their fat and fiber intakes and to the intakes of 2- to 5-year-old children in the households was examined using data from the 1989–91 Continuing Survey of Food Intake by Individuals and Diet Health Knowledge Survey (CSFII/DHKS). Selected households (n = 478) provided 24-hour diet recalls and the households’ main meal planners responded to the DHKS. Meal planner attitude variables were defined according to the Health Belief Model and selected CSFII/DHKS questions served as proxy measures. The relationship of meal planners’ attitudes and knowledge to meal planners’ and childrens fat and fiber consumption at home and in the total diet was analyzed using multiple regression. Several diet-health attitude variables were significantly related to meal planners’ fat and fiber intakes and relationships were similar for foods eaten at home and for foods eaten in the total diet. Knowledge was significantly related to meal planners’ and childrens home fat intake (p

Over consumption of fat by college students: the fast food connection

College students (416) in an introductory nutrition class were surveyed to determine how college students categorize foods and to establish the relationships between fat intake (3‐day diet record), everyday food choices and fat practices (frequency survey), and fast‐food use (attendance and food consumption). Factor analysis of everyday food choices resulted in five groupings, three high‐fat and two low‐fat. Males averaged 84 g fat/day (range 26–212); women 61 g fat/day (range 25–201). Fat intake was almost double for students with the highest fast‐food attendance (97 g) compared to the lowest (50 g). Fast‐food intake does not necessarily contribute a great amount of fat to the overall diet, but is predictive of a certain type of high‐fat dietary pattern.

Haitian street foods and their nutritional contribution to dietary intake

A three month study was conducted in Port‐au‐Prince, Haiti, during the fall of 1983 in order to establish a base of knowledge regarding street foods. One hundred and forty six street food items were identified, described, and classified. A food frequency questionnaire was developed and administered to 174 secondary school students from varied socioeconomic levels to assess their street food consumption. The average consumption of calories and protein were found to be 401 kcalories and 5.8 g of protein. Significant differences in consumption values were found between socioeconomic levels. Street food consumption was found to contribute 18% of the recommended dietary allowance for the Caribbean for energy and 15% for protein. Based on a daily nutrient intake of 7.5 MJ (1580 kcalories) and 37 g of protein for urban school students, 25% of the calories and 16% of the protein in the overall diet were found to be provided by street foods.

Hepatic benzpyrene hydroxylase activity in endrin susceptible and resistant pine mice

Abstract Benzpyrene hydroxylase activity in hepatic microsomes from endrin resistant pine mice was found to be higher than in microsomes from susceptible mice. The hydroxylase activity of resistant offspring was also significantly higher than the parental strain. Pretreatment of resistant mice with dieldren resulted in a further increase in hydroxylase levels. It was concluded that the data presented offer supportive evidence for a heritable as well as an adaptive aspect of the resistance.

Characterization of the hepatic mixed function oxidase system in endrin-resistant and -susceptible pine voles

Abstract Studies were conducted to assess the contribution of the hepatic microsomal mixed function oxidase system to a 7.2-fold difference in susceptibility to the lethal effects of endrin between endrin-resistant and -susceptible pine voles, Microtus pinetorum. Evaluations of microsomal enzyme systems were conducted for basal and endrin-treated pine voles of both strains. The microsomal activity of ICR white mice was investigated to provide a species comparison. Maximal microsomal mixed function oxidase activities were determined in in vitro incubations for the model substrates ethylmorphine, aniline, and benzo(a)pyrene. Vmax values were estimated for the rate of disappearance of benzo(a)pyrene in in vitro incubations. No significant strain differences in basal microsomal enzyme activity were found for the model substrates investigated, although activity was invariably higher in the resistant strain. The concentration of cytochrome P-450 was significantly higher in the resistant vole though actually less than 20% different. The occurrence of significant strain differences in the levels of microsomal enzyme activity induced by endrin were rare. Significant endrin treatment effects on the levels of microsomal enzyme activity for the pine vole were observed but the degree and direction of change depended on the substrate used. A marked species difference in microsomal mixed function oxidase activity was noted between pine voles and white mice. This was particularly evident for endrin-treated animals. The microsomal activity of endrin-treated white mice was greatly induced relative to basal levels. The degree of induction depended on the substrate used. The small strain differences in microsomal enzyme activity for the systems investigated were judged to be insufficient to explain the strain difference in susceptibility to endrin.

Toxicity studies in endrin-susceptible and resistant strains of pine mice☆

Abstract Oral LD50 studies were conducted in strains of endrin-susceptible and resistant pine mice live-trapped in different apple orchards. The degree of resistance to endrin decreased in the orchard once endrin application as a control measure was terminated. Endrin-resistant mice showed a 2-fold degree of cross-resistance to dieldrin and an absence of cross-resistance to the organophosphate Gophacide and to the indirect anticoagulant chlorophacinone. Both Gophacide and chlorophacinone were more lethal to the endrin-resistant mice. Endrin toxicity studies in offspring indicated the resistance is heritable in first generation progeny.

Effect of casein diets on the toxicity of malathion and parathion and their oxygen analogues

SummaryThe toxicities of malathion and parathion and their oxygen analogues were investigated in rats fed different levels of dietary protein. Male weanling rats were fed either a 5 or 20% casein diet for 10 days.Rats fed 5% casein diets were more susceptible to malathion and malaoxon acute toxicity when compared with rats pair-fed 20% casein diet or with rats fed 20% casein dietad libitum. Parathion and paraoxon were likewise more toxic to rats fed the 5% casein diet than to those fed the 20% casein diet (pair-fed or fedad libitum). The urinary excretion of p-nitrophenol as affected by dietary protein was not indicative of the toxicity of parathion and paraoxon.

Endrin metabolism in endrin-susceptible and -resistant strains of pine mice

Distribution of endrin and its metabolites in vivo was measured in order to determine whether differences in toxicity between a resistant (R) strain of pine mouse as opposed to a susceptible (S) strain might be attributed to differences in metabolism of endrin. One of the metabolites recovered was also produced upon incubation with a liver microsomal fraction prepared from the S strain. [14C]Endrin was administered to both strains of animals orally at 0.5 mg/kg. Total recovery of 14C in both feces and urine was 76% for the R strain and 53% for the S strain. Feces and urine were extracted and metabolites separated chromatographically. Both strains produced a single major fecal metabolite, F-1. Three urinary metabolites, U-1, U-2, and U-3, were produced by the S strain while only two metabolites, U-1 and U-2, were identified in urine of the R strain. The fecal metabolite, F-1, and urinary metabolite, U-2, were chromatographically identical. The recovery of F-1 and ethersoluble U-2 for the R strain was 47.9% while that for the S strain was 23.2%. Endrin was metabolized by hepatic microsomes of both strains in vitro to a compound, L-1 that was chromatographically identical to F-1 and U-2. Production of L-1 by microsomes was dependent upon NADPH. The rate of formation of L-1 in vitro by the R strain was greater than the S strain. The apparent Km for the L-1 production from endrin was less than 20 μm.

Urinary excretion of sulfate and glucuronate conjugates in a free living population of adult males

The measured levels of urinary conjugates of sulfate and of glucuronic acid in each subject were compared. Additionally, the potential influence of several dietary and nondietary factors upon conjugate excretion was evaluated using the statistical F-test