The use of endoscopic biopsy in evaluation of polypoid lesions of the colon

Use of flexible endoscopes affords biopsy sampling of polypoid lesions of the colon, especially within the rectum and sigmoid colon by flexible fiberoptic sigmoidoscopes. Histologic examination of colonic biopsies usually allows division of polyps into neoplastic and non-neoplastic categories. There are significant limitations to such biopsies, however, due to sampling error and inability to reach deep submucosal cores of polyps where malignant invasion may occur. When properly aware of its limitations, the endoscopist will find the endoscopic biopsy a valuable aid in planning the therapeutic approach to a polypoid lesion of the colon.     

Control of protein synthesis by amino acid supply. The effect of asparagine deprivation on the translation of messenger RNA in reticulocyte lysates

The enzyme asparaginase, which hydrolyses asparagine to aspartic acid, inhibited cell-free protein synthesis by reticulocyte lysates. The inhibition was rapid and complete when sufficient enzyme was added but could be prevented or reversed by the addition of asparagine. The initial effect of asparaginase appears to be a block in polypeptide chain elongation due to asparagine deprivation, but there are some indications that prolonged incubation under these conditions may give rise to a secondary decrease in initiation of protein synthesis.     

Induction of cytochrome P-450 by glucocorticoids in rat liver. I. Evidence that glucocorticoids and pregnenolone 16 alpha-carbonitrile regulate de novo synthesis of a common form of cytochrome P-450 in cultures of adult rat hepatocytes and in the liver in vivo

We administered a series of steroid hormones to primary nonproliferating cultures of adult rat hepatocytes and found that dexamethasone and other glucocorticoids but not sex steroid hormones, mineralocorticoids, or derivatives of pregnenolone other than pregnenolone 16 alpha-carbonitrile (PCN) stimulated de novo synthesis of an immunoreactive protein, indistinguishable from the form of cytochrome P-450 (P450PCN) induced by PCN in rat liver. No difference were discerned among purified liver cytochromes from rats treated with dexamethasone, PCN or dexamethasone plus PCN, among proteolytic digests of these proteins, or among the immunoprecipitated cytochromes prepared from cultured hepatocytes treated with these steroids as judged by electrophoresis on polyacrylamide gels containing sodium dodecyl sulfate followed by immunoblot analysis. Of the steroids tested, dexamethasone proved to be the most efficacious inducer increasing the rate of synthesis of P450PCN from 0.05% of total cellular protein synthesis in incubated control cultures (measured as incorporation of [3H]leucine into immunoprecipitable P450PCN) to as much as 9.4% in cultures incubated for 5 days in medium containing dexamethasone (10(-5) M). As with traditional glucocorticoid-responsive liver functions, induction of immunoreactive P450PCN was dependent on the concentration of dexamethasone (10(-8) to 10(-5) M) and was promptly reversed upon withdrawal of the steroid. However, during the 24-h interval between 24 to 48 h of culture age the hepatocytes were refractory to either induction or de-induction of immunoreactive P450PCN even though continuous exposure of the cells to dexamethasone (including this interval) was mandatory for maximal induction of P450PCN at 120 h in culture. Unlike cultured rat hepatocytes, HTC hepatoma cultures failed to exhibit dexamethasone-responsive expression of immunoreactive P450PCN. We conclude that glucocorticoids and PCN constitute a specific "class" of synthetic and endogenous inducers of a single form of cytochrome P-450.     

Effect of anoxia and reoxygenation on antioxidant enzyme activities in immortalized brain endothelial cells

Summary The effects of anoxia and reoxygenation on major antioxidant enzyme activities were investigatedin vitro in immortalized rat brain endothelial cells (RBE₄ cells). A sublethal anoxic period of 12 h was assessed for RBE₄ cells using the neutral red uptake test. Anoxia markedly influenced the specific activity of catalase and superoxide dismutase, with no major effect on glutathione peroxidase or glutathione reductase. After 24 h postanoxia, the superoxide dismutase activity modulated by the presence or absence of oxygen returned to control value. Damage and recovery of RBE₄ immortalized rat brain endothelial cells in culture after exposure to free radicals and other oxygen-derived species provides a usefulin vitro model to study anoxia-reoxygenation trauma at the cellular level.     

Babysitting behavior by age/sex classification in squirrel monkeys (Saimiri sciureus)

The aunting behavior in a captive group of 22 squirrel monkeys containing three infants was done in terms of the age/sex classification of those animals involved. The time course of the aunting phenomena and the type and intensity of the interactions between the mothers and the aunts were recorded. Males as well as females were observed to ascertain if the babysitters were sex specific. Observations were gathered before, during, and after a particular threat to any monkey who was carrying an infant. Three categories of protective behavior (protect, retreat, and nothing) were tabulated. The results indicated that most aunting and protection occurred between infant ages 2-1/2-5 weeks when the infants were growing rapidly but not as yet socially self-sufficient. Mothers protected infants the most against juveniles, then subadult males, and least against other adult females. Subadult males were occasionally observed to carry and protect older infants. Aunting behavior was discussed in terms of the selective pressures by which it may have evolved.     

Molecular Epidemiology of Carbapenem Non-Susceptible Acinetobacter baumannii in France

Carbapenem-resistant Acinetobacter baumannii have emerged globally. The objective of this study was to investigate the epidemiology, clonal diversity and resistance mechanisms of imipenem non-susceptible A. baumannii isolates in France. Between December 2010 and August 2011, 132 notifications were collected, including 37 outbreaks corresponding to 242 cases (2 to 55 per cluster). Multilocus sequence typing, pulsed-field gel electrophoresis (PFGE) and characterisation of carbapenemase-encoding genes were performed on 110 non-repetitive isolates. Gene bla _OXA-23 was the most frequently detected (82%), followed by bla _OXA-24 (11%) and bla _OXA-58 (7%). Eleven sequence types (ST) were distinguished, among which sequence types ST1, ST2 (64%), ST20, ST25, ST85 and ST107. Isolates from epidemiological clusters had the same ST and resistance genes, indicating probable transmission within centres. In contrast, PFGE types of isolates differed among centres, arguing against transmission among centers. This study provides the first epidemiological snapshot of the population of A. baumannii with reduced susceptibility to carbapenems from France, and further underlines the predominance of international clones.     

Effects of diet,habitat, and phylogeny on the fecal microbiome of wild African savanna (Loxodonta africana) and forest elephants (L. cyclotis)

The gut microbiome, or the community of microorganisms inhabiting the digestive tract, is often unique to its symbiont and, in many animal taxa, is highly influenced by host phylogeny and diet. In this study, we characterized the gut microbiome of the African savanna elephant (Loxodonta africana) and the African forest elephant (Loxodonta cyclotis), sister taxa separated by 2.6–5.6 million years of independent evolution. We examined the effect of host phylogeny on microbiome composition. Additionally, we examined the influence of habitat types (forest versus savanna) and diet types (crop‐raiding versus noncrop‐raiding) on the microbiome within L. africana. We found 58 bacterial orders, representing 16 phyla, across all African elephant samples. The most common phyla were Firmicutes, Proteobacteria, and Bacteroidetes. The microbiome of L. africana was dominated by Firmicutes, similar to other hindgut fermenters, while the microbiome of L. cyclotis was dominated by Proteobacteria, similar to more frugivorous species. Alpha diversity did not differ across species, habitat type, or diet, but beta diversity indicated that microbial communities differed significantly among species, diet types, and habitat types. Based on predicted KEGG metabolic pathways, we also found significant differences between species, but not habitat or diet, in amino acid metabolism, energy metabolism, and metabolism of terpenoids and polyketides. Understanding the digestive capabilities of these elephant species could aid in their captive management and ultimately their conservation.