National Polyp Study data: evidence for regression of adenomas

The data of the National Polyp Study, a large longitudinal study on surveillance of adenoma patients, is used for testing assumptions on the adenoma-carcinoma sequence. The observed adenoma and colorectal cancer incidence in the National Polyp Study were compared with the simulated outcomes of the MISCAN-COLON model of epidemiology and control of colorectal cancer for the U.S. population based on expert opinion. Variants of this model were explored in order to identify assumptions on the adenoma-carcinoma sequence that are consistent with the study observations. The high observed adenoma detection rates at surveillance and low observed colorectal cancer incidence in the National Polyp Study could only be explained by assuming a high incidence rate of adenomas accompanied by regression of adenomas. The National Polyp Study data suggest that adenoma prevalence results from a dynamic process of both formation as well as regression of adenomas. This lowers the expectations for the effects of colorectal cancer screening strategies that focus on adenoma detection.     

Maxillary Canine Displacement and Genetically Determined Predisposition to Disturbed Development of the Dentition

BACKGROUND: The relationship between maxillary canine displacement and the simultaneous occurrence of "genetically determined predisposition to disturbed development of the dentition" as defined by Hoffmeister was investigated in 675 patients. PATIENTS AND METHODS: Panoramic radiographs taken of each patient during the first and the second mixed dentition periods were evaluated. Canine inclination and the distance between the tip of the canine and a line connecting the cusps of the molars were computed in five different age groups according to Dausch-Neumann. RESULTS: Statistical analysis revealed 34 patients with "potential canine displacement", who exhibited further symptoms of "genetically determined predisposition to disturbed development of the dentition" significantly more frequently than the total group. The symptoms concerned were agenesia, displaced tooth buds, rotated or tilted incisors, aplasia and microdontia of lateral incisors. CONCLUSION: Careful follow-ups in patients with a predisposition to disturbed dental development enables risks to be anticipated and canine displacement to be detected at an early stage.     

Tolerance and Persistence of Ebola Virus in Primary Cells from Mops condylurus,a Potential Ebola Virus Reservoir

Although there have been documented Ebola virus disease outbreaks for more than 40 years, the natural reservoir host has not been identified. Recent studies provide evidence that the Angolan free-tailed bat (Mops condylurus), an insectivorous microbat, is a possible ebolavirus reservoir. To investigate the potential role of this bat species in the ecology of ebolaviruses, replication, tolerance, and persistence of Ebola virus (EBOV) were investigated in 10 different primary bat cell isolates from M. condylurus. Varying EBOV replication kinetics corresponded to the expression levels of the integral membrane protein NPC1. All primary cells were highly tolerant to EBOV infection without cytopathic effects. The observed persistent EBOV infection for 150 days in lung primary cells, without resultant selective pressure leading to virus mutation, indicate the intrinsic ability of EBOV to persist in this bat species. These results provide further evidence for this bat species to be a likely reservoir of ebolaviruses.     

The effect of cholesterol on membrane potentials, proliferation and migration of cultivated endothelial cells]

The influence of cholesterol added as cholesterol containing liposomes [sphingomyelin/cholesterol (1: 1; mol/mol)] or as cholesterol suspensions on cultured bovine aortic endothelial cells was investigated. 10(-6) mol/l cholesterol enhanced membrane potential, 10(-5) mol/l caused depolarisation. The proliferation of the cells was dependent on the concentration influenced in opposite directions too. The proliferation was stimulated by 10(-6) mol/l cholesterol and inhibited by 10(-5) mol/l. The migratory rate of the cells was increased by 10(-6) mol/l and 10(-5) mol/l cholesterol. Our results suggest that exogenous cholesterol is integrated in membranes of the endothelial cells and causes in this way changes of membrane potential, proliferation rate and migratory activity.     

Immunosuppressive and cytostatic effectiveness of the poplar mushroom Tricholoma populinum LANGE

Dry powders or extracts of the fruit bodies of Tricholoma populinum given per as or injected intraperitoneally respectively caused a suppression of the number of plaque forming cells of mice as shown by the hemolysis-plaque-assay. Extracts of the fungi inhibited above that the incorporation of 3H-thymidine into mitogen-stimulated human lymphocytes as observed in the lymphocyte transformation test and retarded the proliferation of cultivated bovine aortic endothelial cells.     

Adult gonadal hormones selectively regulate sexually dimorphic quantitative traits observed in experimental allergic encephalomyelitis

Experimental allergic encephalomyelitis (EAE) and multiple sclerosis (MS) are characterized by strong sexual dimorphisms, many of which may be due to genetically controlled sex hormone effects on the immune system, the central nervous system (CNS), or both. In the present study we used 487 gonadectomized and 376 intact age-matched F(2) mice generated through crosses of B10.S/SgMcdJ and SJL/J mice to assess the role of adult gonadal hormones in regulating clinical and histopathological quantitative traits (QT) associated with EAE in the context of genetic heterogeneity. We found that gonadectomy resulted in different effects, depending on the QT and the sex of the mouse. Ovariectomized mice on average had lower cumulative clinical disease scores, shorter duration of clinical signs, and increased peak disease scores. This trend was accompanied by a significant increase in the incidence of acute, progressive EAE which is more frequently seen in intact and orchiectomized males. Although spinal cord (SC) inflammation was the better predictor of clinical signs of EAE in both sexes, ovariectomized females had considerable reductions in nearly all histopathological QT in both the brain and SC. Orchiectomy resulted in modestly significant increases in disease severity and peak score and earlier onset of clinical signs. With the exception of SC demyelination and lesion scores, orchiectomy had no effect on histopathological QT. Importantly, gonadectomy reduced but did not completely abolish any of the sexually dimorphic clinical QT seen in intact mice. It did however, lead to a significant sexual dimorphism in incidence and severity not seen in intact mice. For histopathological QT, no sexual dimorphism was detected for brain lesions in either intact or gonadectomized mice. In contrast, SC histopathological QT exhibited significant sexual dimorphisms, which were impacted by gonadectomy. The results from this study indicate that within the context of genetic heterogeneity, circulating gonadal hormones influence both clinical and histopathological QT in this model of MS, but they do not solely account for the sexual dimorphisms seen in these traits. Thus, additional mechanisms must play a role in regulating gender differences in autoimmune disease of the CNS.