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Colonic crypts are stereotypical structures with distinct stem cell, proliferating, and differentiating compartments. Colorectal cancers derive from colonic crypt epithelia but, in contrast, form morphologically disarrayed glands. In this study, we investigated to which extent colorectal cancers phenocopy colonic crypt architecture and thus preserve structural organization of the normal intestinal epithelium. A subset of colon cancers showed crypt-like compartments with high WNT activity and nuclear β-Catenin at the leading tumor edge, adjacent proliferation, and enhanced Cytokeratin 20 expression in most differentiated tumor epithelia of the tumor center. This architecture strongly depended on growth conditions, and was fully reproducible in mouse xenografts of cultured and primary colon cancer cells. Full crypt-like organization was associated with low tumor grade and was an independent prognostic marker of better survival in a collection of 221 colorectal cancers. Our findings suggest that full activation of preserved intestinal morphogenetic programs in colon cancer requires in vivo growth environments. Furthermore, crypt-like architecture was linked with less aggressive tumor biology, and may be useful to improve current colon cancer grading schemes.  相似文献   
3.
Summary The degree of satellite association was found to be significantly higher in phytohemagglutinin (PHA)-stimulated lymphocytes from cystic fibrosis (CF) patients than from those of control individuals. PHA-stimulated lymphocytes from obligatory heterozygotes for the CF mutant allele showed an intermediate degree of satellite association. The degree of satellite association was estimated by the frequency of cells exhibiting associations, by the number of associations per cell, and by the number of chromosomes in an association. The differences in the degree of satellite association were dependent on the concentration of colchicine used for cell arrest. These findings may assist in developing a diagnostic method for the early identification of heterozygotes for the CF allele and for prenatal detection of CF homozygous fetuses.This paper is based on a portion of a dissertation to be submitted by Y. Ravia in partial fulfilment of the Ph. D. requirements in the Graduate School of Tel Aviv University  相似文献   
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Size at birth and some sociodemographic factors in gypsies in Hungary   总被引:1,自引:0,他引:1  
In 10,108 babies born to gypsy parents, birth weight, birth length and gestational age are compared with a national reference sample, taking into account maternal education, age, and birth interval. The gypsy babies tend consistently to be smaller, and this difference is attributable to the circumstances in which the gypsies live as well as the poorer maternal education. There appears to be a vicious circle--poor hygiene and living conditions adversely affect birth size, which in turn puts the child at a disadvantage in terms of survival, health and development.  相似文献   
6.
The 2-hydroxy and 4-hydroxyestradiols (2-/4-OHE2) caused marked cytotoxic effects, including vacuolation and nuclear changes, in rat epididymal epithelia, after exposure to very low levels (40 ng/rat/week) for 20 weeks. The effects of the 2-/4-OHE2 metabolites were more pronounced than that of estradiol-17β(E2).  相似文献   
7.
Joubert  W. A.  Britz  T. J. 《Microbial ecology》1987,13(2):159-168
Fifty-two aerobic and facultative anaerobic and 57 anaerobic bacterial isolates were obtained from an acidogenic phase digestion system. These isolates were characterized and the similarities between the different strains were calculated using Sokal and Michener's similarity coefficient. The aerobic and facultative anaerobic strains clustered in two major groups with the strains of the first main group being gram-negative fermentative rods, representing the generaKlebsiella, Enterobacter, Escherichia andAeromonas. Isolates of the second group were gram-positive streptococci similar toStreptococcus lactis. The strict anaerobic isolates also clustered into two main groups with strains of cluster A being identified as members of the genusFusobacterium while strains in cluster B were members of the genusBacteroides. Hypothetical mean organisms were calculated for each cluster and used in further culture studies. The major products of the continuously fed acidogenic phase reactor were ethanol and acetic, propionic, and butyric acids. In batch cultures, ethanol, acetic acid, diacetyl, and 2,3-butanediol were formed by the strains as major products both under aerobic and anaerobic conditions. The ability of the aerobic and facultative anaerobic strains to be metabolically active under anaerobic conditions indicates a prominent role in acidogenic reactors.  相似文献   
8.
Summary An analysis was made of the effects of different sampling and extraction techniques on the amounts and pattern of monoterpenoids isolated from needles of Norway spruce. The following isolation and analysis procedure was finally adopted: liquid nitrogen-cooled needles were pulverized by a microdismembrator, extracted with pentane overnight at 2°–3°C and concentrated to a volume not less than 3 ml/g fresh weight on a Vigreux column. The crude extract was injected splitless (with solvent split) onto a cold programmed temperature vaporized (PTV) precolumn of a gas chromatograph and the vaporizable compounds heated to a capillary column. This method was tested for production of artefacts and quantitative extraction and applied to needles of eleven 80-year-old spruce trees.  相似文献   
9.
Although the Kunitz-type proteinase inhibitors from the seeds of various Erythrina species have similar molecular weights (approximately 20,000), and share many other chemical characteristics, they could nevertheless be divided into three groups on the basis of their relative abilities to inhibit chymotrypsin, trypsin and tissue plasminogen activator. Group a inhibitors were relatively specific for chymotrypsin; they were poor inhibitors of trypsin and had no apparent effect upon tissue plasminogen activator. Group b proteins inhibited trypsin strongly and chymotrypsin slightly less effectively. They had no effect upon t-PA. Group c inhibitors inhibited trypsin, chymotrypsin and t-PA. Analysis of the amino acid composition of the three groups of inhibitors revealed major differences in alanine content. Minor differences in the content of most other amino acids were also noticed. Group b and group c inhibitors had, in most cases, the same reactive sites (Arg-Ser). The sequences neighbouring the reactive sites showed a significant degree of homology. Chemical modification of arginine in proteinase inhibitors from the seeds of E. latissima and soybeans using 1-2-cyclohexanedione confirmed the presence or absence of arginine in the reactive sites.  相似文献   
10.
The cytostatic effects of essential fatty acid metabolic intermediates and of some prostaglandins and leukotrienes in vitro have been extensively documented. The essential fatty acids (EFAs) exhibit no side-effects when taken as a dietary supplement, even in large doses. Primary Liver Cancer (PLC) is a fatal disease in our area as it is always multifocal in nature. In vitro studies have shown a cytostatic effect of gamma-linolenic acid (GLA) on primary liver cancer cells. In a double-blind placebo controlled trial, using Evening Primrose Oil (as a source of GLA) as a dietary supplement in PLC patients, no statistically significant effect was observed on survival time or liver size. There was however a statistical significant beneficial effect on Gamma Glutamyl transferase values as a measure of liver function. No side-effects were observed. The large size of tumour and the low doses of GLA used in this trial probably explain the lack of significant effect on survival times.  相似文献   
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