Canine bile acid enterohepatic circulation

The enterohepatic circulation (EHC) of bile acids has been studied in fasting dogs with portacaval shunt maintained in the steady state. In such animals the rate of EHC is proportional to systemic blood bile acid concentration. Bile acid EHC was irregular (20 to 100% variation) when measured at 15 minute or hourly intervals. Studies showed that the variations persisted in cholecystectomized and sphincterectomized animals. The irregularities were enhanced by bethanechol chloride which increases intestinal peristalsis and suppressed by diphenoxylate HCl which slows peristalsis. The variations appear to arise from irregular patterns of intestinal peristalsis. This phenomenon may explain some variations in blood bile acid concentration observed in patients with liver disease.     

EFFECTS OF DARKNESS AND OF STREPTOMYCIN ON THE FINE STRUCTURE OF EUGLENA GRACILIS

Siegesmund , Kenneth A., Walter G. Rosen , and Stanley R. Gawlik . (Marquette (J., Milwaukee, Wis.) Effects of darkness and of streptomycin on the fine structure of Euglena gracilis. Amer. Jour. Bot. 49 (2) : 137–145. Illus. 1962.—Dark-grown Euglena gracilis cells, transferred from streptomycin (SM)-containing medium to SM-free medium 5 days before transfer to light, turn green normally, indicating that proplastids are unaffected by SM. SM-bleached cells, grown in light, contain numerous bodies composed of concentric lamellae (CL bodies). These differ from chloroplasts in that their lamellae lack electron-dense dots, are not coalesced, and they lack a 3-layered limiting membrane and pyrenoids. CL bodies are absent from dark-grown normal and dark-grown SM-bleached cells, as well as from light-grown normal cells. It is suggested that CL bodies result from a derangement of chloroplast synthesis caused by SM blockage of chlorophyll synthesis.     

Absence of sebaceous glands from the oral mucosa of non-human primates

Whereas sebaceous glands unassociated with hairs are a common and easily seen feature of the mucosa of the cheek and red margin of the lip in man, no glands of this type were found in this situation in autopsy specimens from 47 macaques and single specimens of 5 other species.     

Evolutionary lines among Salmonella enteritidis phage types are identified by insertion sequence IS200 distribution

A survey was made of the presence, copy number and location of the Salmonella-specific DNA insertion element IS200, within the genomes of the 27 phage type strains of Salmonella enteritidis. All the phage type strains contained copies of IS200 revealed by genomic Southern blot hybridizations with a 300-bp DNA probe internal to the element. Restriction site variation around IS200 insertion sites was examined. Three fundamental patterns of hybridization corresponding to chromosomal IS200 loci were found. In terms of population genetics, these 'IS200 profiles' correspond to clonal lineages of recent evolutionary origin, and underline the phage-typing scheme for epidemiological subdivision of S. enteritidis. The molecular analysis is consistent with genetic selection pressures which are apparent in the observed epidemiological distribution of S. enteritidis, since each clonal lineage contained one of the phage types of major clinical importance in the U.K.