In Experiment 1, subjects ranging from age 9 to college age were told the affective reactions of a teacher toward a failing student. The affects included anger, pity, guilt, surprise, and sadness. Subjects were asked to infer the cause of the student's failure; was it due, for example, to low ability or lack of effort? For all ages, there were systematic linkages between the following affect-attribution pairings: anger-lack of effort, guilt-poor teaching, and surprise-lack of effort. In addition, among the adults there was an association between pity and low ability. A second experiment, using subjects from 5 to 9 years of age, examined only the affects of anger and pity. This experiment revealed that a relation between anger-lack of effort was exhibited by the youngest age children, whereas a pity-lack of" ability association was displayed only by the older children. The implications of the findings for self-concept are discussed.

Cholesterol 7or-hydroxylase or cholesterol, reduced NADP : oxygen oxidoreductase (7a-hydroxylating), the initial and possibly rate-limiting step in bile acid formation is a mixed function oxidase of rat liver microsomes. This enzyme requires NADPH and oxygen. The enzyme system is induced by feeding the bile salt sequestering agent, cholestyramine, this compound effectively breaks the enterohepatic circulation of bile salts and cause about a five-fold increase in the activity of the enzyme within four days.The cholesterol 7a-hydroxylase enzyme has a K , for oxygen of approximately 20 pM. It is inhibited by carbon monoxide and this inhibition is released by irradiation with light of 450 nm. The enzyme is not inhibited by cyanide but is inhibited by cytochrome c and p-chloromercuribenzoate. The enzyme therefore appears to be a typical liver microsomal mixed function oxidase, involving NADPH, cytochrome c reductase and cytochrome P450.The cholesterol 7or-hydroxylase has an activation energy of 22 kcal/mol and is inhibited by the product of the reaction, namely, 7or-hydroxycholesterol and ah0 inhibited by bile acids and bile salts.

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1. Forty-eight male rats were fed sequentially for 14 d periods on diets containing different fibre contents. 2. One of the high-fibre diets was a commercial pelleted diet. The other was a low-fibre diet supplemented 3. At the end of each feeding period eight rats were killed. Liver microsomal cholesterol 7a-hydroxylase 4. The different diets did not significantly alter the total intestinal bile acids, but affected the distribution 5. On the high-fibre diets deoxycholate, and hyodeoxycholate tended to be increased. 6. On the low-fibre diets the a-, /3-and o-muricholic acids tended to be increased. 7. Liver microsomal cholesterol 7a-hydroxylase activity was lower in rats fed on the low-fibre and branwith zoo g wheat bran/kg.(EC 1.14.1.-) activity and bile acid content of small intestine and colon were determined. and qualitative pattern in the colon and small intestine.supplemented low-fibre diets compared with that in rats fed on the commercial pelleted diet.The effect of dietary fibre on rat bile acid metabolism has been investigated by several groups. The addition of bran to a semi-synthetic diet resulted in an increase in total bile acids in the small intestine of the rat (Eastwood & Boyd, 1967). Gustaffson & Norman (1969) using labelled cholate added to a semi-synthetic, commercial pelleted diet, and a semisynthetic diet supplemented with 200 g cellulose/kg, fed to rats showed that cholate and certain bile acid metabolites were increased in the small intestine on the commercial pelleted diet, but the addition of cellulose to the semi-synthetic diet had no effect on the small intestinal cholate pool. The total intestinal bile acid pool has been measured in Wistar rats fed on commercial pelleted and semi-synthetic diets (Fisher et ul. 1976). These authors showed that the total bile acid pool was increased on the commercial pelleted diet, but over-all there was no qualitative change in bile acid pattern. Sacquet et al. (1977) demonstrated that re-infecting the colon of germ free rats with heat-resistant bacteria isolated fromfaecesled to w-muricholic acid emerging as the major colonic bile acid. The metabolism of bile acids in the rat is as follows : W. G. BRYDON A N D O T H E R SIn this study we supplemented a semi-synthetic, low-fibre diet with 200 g wheat bran/kg and compared the pool size and pattern of bile acids in the small intestine and colon separately, with rats fed on a commercial pelleted or semi-synthetic diet alone.The rate limiting enzyme in the conversion of cholesterol to bile acids in the liver is the microsomal cholesterol 7a-hydroxylase (EC I . 14. I .-) (Danielsson et al. 1967). This oxygenase is located in the endoplasmic reticulum and is sensitive to changes in the enterohepatic circulation of bile acids. Liver microsomal cholesterol 7a-hydroxylase activity was measured during the different feeding regimens. MATERIALS A N D METHODSForty-eight mature male rats of Wistar strain were used in this study. The animals weighed approximately 200 g at the start of the experiment, and received ...