Age-dependence of hepatic dimethylnitrosamine-demethylase activity in the rat

The mixed-function oxidase which activates the carcinogen dimethylnitrosamine (DMN) was determined in the rat liver as a function of animal age. DMN-demethylase activity increased considerably at first to reach a maximum on day 29, and then substantially decreased to day 59; thereafter, enzyme activity remained essentially stable up to at least day 110. Pretreatment with 3-methylcholanthrene, which caused a pronounced decrease in this enzyme activity, did not affect the general shape of the age-dependence curve. The results suggest that rats between weaning and sexual maturity are more susceptible to the carcinogenic effects of pulse doses of DMN than are neonates or adult animals.     

A therapeutic milieu for establishing and expanding communicative behaviors in psychotic children

This study describes a clinical intervention program that was used to facilitate development of receptive and expressive language skills in a group of four psychotic children. A group format utilizing an interactive language development teaching procedure combined with a therapeutic milieu was shown to be effective in establishing and expanding communicative behaviors in psychotic children. Nine diagnostic measures were utilized to assess children's performance prior to therapy and at the end of three-month and six-month intervals. Results indicated substantial reduction of delayed and immediate echolalia, jargon, inappropriate stress, pitch, and intonation. Substantial improvement was noted in expressive syntactic and morphological functioning and in the children's ability to generate novel utterances about day-to-day experiences, family, and toys. Increases in children's concept of body image and ego functioning paralleled their improvement in receptive and expressive language development.     

Effect of histamine on technetium-99m excretion by gastric mucosa

The ability of histamine to increase excretion of 99mtechnetium by gastric mucosa was investigated in dogs with Heidenhain pouches and denervated antral pouches. Histamine increased Heidenhain pouch 99mtechnetium output in a dose-related manner, and 99mtechnetium output was related linearly to acid output. Antral pouch 99mtechnetium output was unchanged by increasing doses of histamine. The study suggests that concomitant use of histamine may improve the accuracy of 99mtechnetium scanning in the clinical diagnosis of conditions caused by ectopic gastric mucosa.     

Intestinal ascorbic acid transport following diets of high or low ascorbic acid content

Active transport of ascorbic acid in ileum is mediated by a carrier mechanism at the brush border membrane. This mechanism may show compensatory changes in activity in response to alterations of dietary ascorbic acid content. The unidirectional influx of ascorbic acid across the brush border into epithelial cells of guinea pig ileum was determined in vitro. Influx was significantly reduced in scorbutic animals and following 14 or 28 days of high doses (5 or 25 times normal) of ascorbic acid. The transport rate was reduced by intramuscular administration of ascorbic acid, suggesting that the transport mechanism may respond to circulating levels of the vitamin.