Pharmacology of the ACAT inhibitor avasimibe (CI-1011)

Avasimibe is a novel orally bioavailable ACAT inhibitor, currently under clinical development (phase III trials). It was safe when administered to rats, dogs, and humans. In vitro studies in human macrophages demonstrated that avasimibe reduces foam cell formation not only by enhancing free cholesterol efflux, but also by inhibiting the uptake of modified LDL. The concentration-dependent reduction in cellular cholesteryl ester content in these cells was not accompanied by an increase in intracellular free cholesterol, which is in agreement with a good safety profile for avasimibe. In the liver, avasimibe caused a significant reduction in the secretion of apo B and apo B-containing lipoproteins into plasma. Avasimibe induced cholesterol 7alpha-hydroxylase and increased bile acid synthesis in cultured rat hepatocytes, and its administration to rats did not produce an increase in lithogenicity index of the bile. The hypolipidemic efficacy of the compound was demonstrated in cholesterol-fed as well as in non-cholesterol-fed animals. In these models, plasma cholesterol levels were reduced, mainly due to the decrease in the non-HDL cholesterol fraction. Clinical data are scarce, but in a study performed in 130 men and women with combined hyperlipidemia and hypoalphalipoproteinemia, avasimibe, 50-500 mg/day, significantly reduced plasma total triglyceride and VLDL-cholesterol. Although total cholesterol, LDL-cholesterol, and HDL-cholesterol were unchanged, it must be stressed that animal data suggest that avasimibe may have direct antiatherosclerotic activity in addition to its cholesterol-lowering effect. Avasimibe treatment can also contribute to increase plaque stability, as it reduces the accumulation of lipids in the arterial wall, inhibits macrophage infiltration into the media and reduces matrix metalloproteinase expression and activity. Moreover, avasimibe and statins have been shown to have synergistic effects, and the combination therapy may not only inhibit atherosclerotic lesion progression but also induce lesion regression, independently of changes in plasma cholesterol.     

Common genetic evolutionary pathways in familial adenomatous polyposis tumors

Cancer cells progress through the accumulation of genetic alterations. Familial adenomatous polyposis (FAP) tumors provide an excellent model to unravel the molecular steps underlying malignant transformation. Global genomic damage was assessed in 56 adenomas and 3 carcinomas from six FAP patients and compared with that of sporadic adenomas and carcinomas. Evolutive trees were traced after application of maximum likelihood clustering and split decomposition methods to the analysis of comprehensive genetic profiles generated by diverse molecular approaches: arbitrarily primed PCR, comparative genomic hybridization, and flow cytometry. Overall, genomic damage as assessed by arbitrarily primed PCR was lower in familial adenomas than in sporadic adenomas and carcinomas. Comparative genomic hybridization data also show a low number of alterations in the majority of FAP adenomas. Tumors of the same patient were likely to share specific genetic alterations and may be grouped into one or two clusters. Putative common pathways were also identified, which included tumors of up to three different patients. According to our data, FAP tumors accumulate specific genetic alterations and in a preferred order that is characteristic of each individual. Moreover, the particular genetic background and environmental conditions of a FAP patient restrain the molecular evolution portrait of synchronous tumors.     

Frequent display of human papillomavirus type 16 E6-specific memory t-Helper cells in the healthy population as witness of previous viral encounter

Genital human papillomavirus (HPV) infection is common and the majority of infected individuals successfully deal with this virus. Clearance of HPV is presumably mediated by T cells but HPV-16-specific T-cell memory was usually detected in patients with progressive disease and not in healthy subjects, suggesting that HPV-immunity comes too late. We now show the presence of HPV-16 E6-specific memory T-helper (Th) responses in a major fraction (12 of 20) of healthy individuals by application of the IFN-gamma-ELISPOT assay. Although nearly all E6-peptides were recognized, the majority of the responders targeted peptide sequences of the COOH-terminal half (E6(81-158)) of HPV-16 E6. In a direct comparison, the presence of HPV-16 E6-specific T cells coincided with HPV-16 E2-specific T-cell reactivity in healthy individuals, whereas hardly any HPV-16 E7-specific Th immunity was found. This indicates that the induction of T-cell reactivity against HPV-16 E7 is suboptimal during infection when compared with that against HPV-16 E2 and HPV-16 E6. In conclusion, the presence of HPV-16 E6-specific Th memory in the healthy population demonstrates that HPV infection leads to T-cell immunity against immediate early proteins expressed during infection. Because this HPV-16 E6-specific T-cell immunity was frequently detected in healthy subjects, our data suggest that the observed IFN-gamma-producing proliferating T cells circulating in the peripheral blood play a role in protection against persistent HPV infection and associated development of malignancies.     

Proteomic analysis of intestinal epithelial cells expressing stabilized beta-catenin

Aberrant accumulation of beta-catenin protein because of mutation of either the beta-catenin or adenomatous polyposis coli gene plays an essential role in the development of colorectal carcinoma. We established previously a stable clone of the rat small intestinal epithelial cell line IEC6, which is capable of inducing stabilized beta-catenin protein lacking NH(2)-terminal glycogen synthase kinase-3beta phosphorylation site under a strict control of the tetracycline-regulatory system. This clone, IEC6-TetOFF-beta-catenin DeltaN89, shows in vitro polypoid growth on the removal of doxycycline and seems to be an appropriate model for analyzing the molecular mechanisms of early intestinal carcinogenesis. Of >2000 protein spots displayed by newly developed two-dimensional difference gel electrophoresis, 22 were found to be up- or down-regulated on the induction of stabilized beta-catenin. The majority of these proteins fell into two categories: (a) redox-status regulatory proteins and (b) cytoskeleton-associated proteins. Representatively, a key redox-status regulatory protein, manganese superoxide dismutase, up-regulated in IEC6 cells expressing stabilized beta-catenin protein, was overexpressed in adenoma and adenocarcinoma cells of familial adenomatous polyposis patients in parallel with the accumulation of beta-catenin. These results suggest that aberrant accumulation of beta-catenin might contribute to colorectal carcinogenesis by affecting redox status in the mitochondria of intestinal epithelial cells.     

Managing children with constipation: a community perspective

Two clinical nurse specialists explain the nature of constipation in children and how the primary health care team can achieve successful treatment and management strategies for this condition. Constipation in children is a common and often complex problem. It may begin at four months of age in relation to weaning, or at around two years of age in relation to potty training. Constipation can be a distressing problem for the child and the family. Treatment failure rates are high, frequently reflecting poor understanding of the pathophysiology of constipation and inappropriate management. Symptoms include infrequent defaecation, pain and distress and refusal to defaecate. Causes include a poor intake of dietary fibre and fluid, emotional disturbances, possibly intercurrent infection and change in routine. Management of children with constipation includes an increase in dietary fibre and fluids, behaviour modification and laxative medication. For treatment to be effective there should be regular follow-up. Management of this chronic problem by nurses is viewed as effective and acceptable to parents.     

Comparisons of colon–cancer survival among european countries: The eurocare study

Under the aegis of Eurocare, a European Union project to assemble survival data from population-based cancer registries and analyze them according to standardized procedures, we have investigated and compared colon-cancer survival in 10 European countries. We analyzed 68,283 colon-cancer cases diagnosed between 1978 and 1985 and followed for at least 6 years. After calculating relative survival, putative factors prognostic for survival were investigated by univariate and multiple-regression analyses. Important intercountry colon-cancer survival differences exist within Europe, which are not explained by methodological differences, nor by demographic confounders. In patients aged 60 to 69, the mean European 5-year cumulative relative survival was 40%. Switzerland, Finland and The Netherlands had significantly higher 5-year relative survival, while one area in the UK and Cracow in Poland had significantly lower survival than this European estimate. Prognosis improved over time: from 1978 to 1985, the risk of death was reduced by about 4% per year in all countries studied. Age at diagnosis is inversely related to prognosis. Differences in health provision and hence in quality of care and stage at presentation seem largely responsible for the differences in colon-cancer survival found in the EUROCARE countries.     

Press Releases of Science Journal Articles and Subsequent Newspaper Stories on the Same Topic

Context.— Scientific journals issue press releases to disseminate scientific news about articles they publish. Objective.— To assess whether press releases about journal articles were associated with publication of subsequent newspaper stories. Design.— Retrospective content analysis of newspaper stories, journal press releases, and journal tables of contents. From December 1, 1996, to February 28, 1997, press releases and tables of contents were collected from BMJ, Nature, Science, and The Lancet, along with newspaper stories on scientific research published in The New York Times (United States), Le Figaro and Le Monde (France), El País and La Vanguardia (Spain), La Repubblica (Italy), and the International Herald Tribune. Main Outcome Measurements.— Number of newspaper stories that contained reference to articles appearing in the 4 scientific journals, number of newspaper stories that referred to journal articles described in press releases, and the order in which journal articles were mentioned in press releases. Results.— Of the 1060 newspaper stories analyzed, 142 referred to journal articles; of these, 119 (84%) referred to articles mentioned in press releases and 23 (16%) referred to journal articles not mentioned in press releases (comparison of proportions, P =.03). Articles described first or second were referenced in more newspapers than articles described later in the press release (P=.01 by ² analysis). Conclusions.— Journal articles described in press releases, in particular those described first or second in the press release, are associated with the subsequent publication of newspaper stories on the same topic.      

A subfraction of B220(+) cells in murine bone marrow and spleen does not belong to the B cell lineage but has dendritic cell characteristics

Although CD45R/B220 is commonly used as a pan-B cell marker in the mouse, not all B220(+) cells belong to the B cell lineage. Here we report the characterization of a subpopulation of B220(+)CD19(-) cells in murine bone marrow, which failed to express markers that are present in early CD19(--) B cell precursors. Instead, these cells expressed low levels of MHC class II and CD11c, which are typically found on dendritic cells (DC). Moreover, these B220(+)CD19(-)CD11c(+) cells expressed Gr-1, indicating that they are related to the recently identified murine plasmacytoid DC or their progenitors. Therefore, we evaluated surface marker expression of the B220(+)CD19(-)CD11c(+) cells in lymphoid tissues of C57BL/6 mice, recombinase activating gene-1 deficient mice, lacking mature B and T lymphocytes, and mice with a targeted disruption of the Ig H chain mu membrane exon (mu MT), lacking mature B lymphocytes. When comparing bone marrow and spleen, we found that the surface profiles of B220(+)CD19(-)CD11c(+) cells were remarkably similar, indicating that they are in a comparable maturation or activation stage in the two lymphoid compartments. In addition, the almost complete absence of peripheral B220(+) B-lineage cells in mu MT mice allowed the anatomical localization of the B220(+)CD19(-)CD11c(+) cells to the red pulp and the T cell areas in the spleen. Taken together, our findings indicate that the mouse bone marrow contains a recirculating population of B220(+)CD19(-) CD11c(+) plasmacytoid DC, the development of which is largely independent of the presence of mature T and B cells.