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1.
Dr. Shigeru Sakiyama Yohko Nakamura Katsuo Tokunaga Hiroshi Takazawa Yoshinori Ohwaki Toshio Nagano 《Cell and tissue research》1989,258(2):225-231
Summary In-situ hybridization experiments have been performed using isoactin ( and )-specific riboprobes in various tissues of the rat and mouse. Distribution of the grains of actin mRNAs for both and types was similar throughout sections of the rat testis. Although both mRNAs were evenly distributed in the seminiferous tubule, extremely heavy labeling was observed in about 10% of the seminiferous tubules that could be identified as stage XII of spermatogenesis. At high magnification, grains of the mRNA were found in the cytoplasm of elongating spermatids and in the Sertoli cell cytoplasm at the adluminal side. Much higher density of the grains of mRNA was observed in the neck region of the spermatids at stage XII. Thus, the dense distribution of cytoskeletal actin mRNAs is stage-specific in the tubule during spermatogenesis in the rat. The high expression of both and actin mRNAs was also observed in the epithelial cells of the intestinal crypts. 相似文献
2.
《Bioscience, biotechnology, and biochemistry》2013,77(9):2198-2205
We estimated the nutritional availability of selenium (Se) in Se-enriched Kaiware radish sprouts (SeRS) by the tissue Se deposition and glutathione peroxidase (GPX) activity of rats administered the sprouts, and examined the effect of SeRS on the formation of aberrant crypt foci (ACF) in the colon of mice administered 1,2-dimethylhydrazine (DMH) to evaluate anti-tumor activity. Male weanling Wistar rats were divided into seven groups and fed a Se-deficient basal diet or the basal diet supplemented with 0.05, 0.10, or 0.15 μg/g of Se as sodium selenite or SeRS for 28 d. Supplementation with Se dose-dependently increased serum and liver Se concentrations and GPX activities, and the selenite-supplemented groups showed a higher increase than the SeRS-supplemented groups. The nutritional availability of Se in SeRS was estimated to be 33 or 64% by slope ratio analysis. Male 4-week-old A/J mice were divided into seven groups and fed a low Se basal diet or the basal diet supplemented with selenite, SeRS, or selenite + non-Se-enriched radish sprouts (NonSeRS) at a level of 0.1 or 2.0 μg Se/g for 9 weeks. After 1 week of feeding, all mice were given six subcutaneous injections of DMH (20 mg/kg) at 1-week intervals. The average number of ACF formed in the colon of mice fed the basal diet was 4.3. At a supplementation level of 0.1 μg Se/g, only SeRS significantly inhibited ACF formation. At a supplementation level of 2.0 μg Se/g, both selenite and SeRS significantly inhibited ACF formation. The addition of NonSeRS to the selenite-supplemented diets tended to inhibit ACF formation, but this was not statistically significant. These results indicate that SeRS shows lower nutritional availability but higher anti-tumor activity than selenite. 相似文献
3.
Testing for spatial correlation in nonstationary binary data, with application to aberrant crypt foci in colon carcinogenesis 总被引:2,自引:0,他引:2
Apanasovich TV Sheather S Lupton JR Popovic N Turner ND Chapkin RS Braby LA Carroll RJ 《Biometrics》2003,59(4):752-761
In an experiment to understand colon carcinogenesis, all animals were exposed to a carcinogen, with half the animals also being exposed to radiation. Spatially, we measured the existence of what are referred to as aberrant crypt foci (ACF), namely, morphologically changed colonic crypts that are known to be precursors of colon cancer development. The biological question of interest is whether the locations of these ACFs are spatially correlated: if so, this indicates that damage to the colon due to carcinogens and radiation is localized. Statistically, the data take the form of binary outcomes (corresponding to the existence of an ACF) on a regular grid. We develop score-type methods based upon the Matern and conditionally autoregressive (CAR) correlation models to test for the spatial correlation in such data, while allowing for nonstationarity. Because of a technical peculiarity of the score-type test, we also develop robust versions of the method. The methods are compared to a generalization of Moran's test for continuous outcomes, and are shown via simulation to have the potential for increased power. When applied to our data, the methods indicate the existence of spatial correlation, and hence indicate localization of damage. 相似文献
4.
Nobukatsu Horita Kiichiro Tsuchiya Ryohei Hayashi Keita Fukushima Shuji Hibiya Masayoshi Fukuda Yoshihito Kano Tomohiro Mizutani Yasuhiro Nemoto Shiro Yui Ryuichi Okamoto Tetsuya Nakamura Mamoru Watanabe 《Biochemical and biophysical research communications》2014
Background and aims
The dynamics of intestinal stem cells are crucial for regulation of intestinal function and maintenance. Although crypt stem cells have been identified in the intestine by genetic marking methods, identification of plural crypt stem cells has not yet been achieved as they are visualised in the same colour.Methods
Intestinal organoids were transferred into Matrigel® mixed with lentivirus encoding mCherry. The dynamics of mCherry-positive cells was analysed using time-lapse imaging, and the localisation of mCherry-positive cells was analysed using 3D immunofluorescence.Results
We established an original method for the introduction of a transgene into an organoid generated from mouse small intestine that resulted in continuous fluorescence of the mCherry protein in a portion of organoid cells. Three-dimensional analysis using confocal microscopy showed a single mCherry-positive cell in an organoid crypt that had been cultured for >1 year, which suggested the presence of long-lived mCherry-positive and -negative stem cells in the same crypt. Moreover, a single mCherry-positive stem cell in a crypt gave rise to both crypt base columnar cells and transit amplifying cells. Each mCherry-positive and -negative cell contributed to the generation of organoids.Conclusions
The use of our original lentiviral transgene system to mark individual organoid crypt stem cells showed that long-lived plural crypt stem cells might independently serve as intestinal epithelial cells, resulting in the formation of a completely functional villus. 相似文献5.
The development of ACF (aberrant crypt foci), adenoma and cancer following intrarectal administration of the alkylating agent N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) has been described. However, microscopic lesions not previously reported were observed as soon as two weeks following carcinogen treatment. These lesions protrude slightly over the epithelial lining of the colon, with a micropolyp-like appearance. Oriented sections show that the centre of these lesions present pseudo-“cystic” appearance, with disorganized crypts made of normal cells. The chorion of the lesion is invaded by numerous inflammatory cells and some ACF may be present nearby. The epithelium lining the cysts and the distorted crypts shows expression of gastric mucin M1/MUC5AC, an early marker of colonic carcinogenesis which is not present in normal colon. This mucin is retained within the “cysts” together with some inflammatory cells.The micropolyps observed contain in a minute form some histological elements described in ulcerative colitis or short-term radiotherapy (distortion of crypts, crypt abscesses, increase of chorion cellularity, infiltration by immune cells). In addition, the presence of bifid crypts nearby suggests mucosal regeneration.Our hypothesis is that these modifications are steps in a normal healing pathway that may in some cases degenerate into precancerous lesions and cancer. 相似文献
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7.
K+-conductive pathways were evaluated in isolated surface and crypt colonic cells, by measuring 86Rb efflux. In crypt cells, basal K+ efflux (rate constant: 0.24 ± 0.044 min−1, span: 24 ± 1.3%) was inhibited by 30 mM TEA and 5 mM Ba2+ in an additive way, suggesting the existence of two different conductive pathways. Basal efflux was insensitive to apamin,
iberiotoxin, charybdotoxin and clotrimazole. Ionomycin (5 μM) stimulated K+ efflux, increasing the rate constant to 0.65 ± 0.007 min−1 and the span to 83 ± 3.2%. Ionomycin-induced K+ efflux was inhibited by clotrimazole (IC50 of 25 ± 0.4 μM) and charybdotoxin (IC50 of 65 ± 5.0 nM) and was insensitive to TEA, Ba2+, apamin and iberiotoxin, suggesting that this conductive pathway is related to the Ca2+-activated intermediate-conductance K+ channels (IKca). Absence of extracellular Ca2+ did neither affect basal nor ionomycin-induced K+ efflux. However, intracellular Ca2+ depletion totally inhibited the ionomycin-induced K+ efflux, indicating that the activation of these K+ channels mainly depends on intracellular calcium liberation. K+ efflux was stimulated by intracellular Ca2+ with an EC50 of 1.1 ± 0.04 μM. In surface cells, K+ efflux (rate constant: 0.17 ± 0.027 min−1; span: 25 ± 3.4%) was insensitive to TEA and Ba2+. However, ionomycin induced K+ efflux with characteristics identical to that observed in crypt cells. In conclusion, both surface and crypt cells present
IKCa channels but only crypt cells have TEA- and Ba2+-sensitive conductive pathways, which would determine their participation in colonic K+ secretion. 相似文献
8.
Cell culture studies have suggested that arsenic exposure results in decreased S-adenosylmethionine (SAM), causing DNA hypomethylation. Previously, we have shown that hepatic SAM is decreased and/or S-adenosylhomocysteine increased in arsenic-deprived rats; these rats tended to have hypomethylated DNA. To determine, the
effect of dietary arsenic on dimethylhydrazine (DMH)-induced aberrant crypt formation in the colon, Fisher 344 weanling male
rats were fed diets containing 0,05, or 50 μg As (as NaAsO2)/g. After 12 wk, dietary arsenic affected the number of aberrant crypts (p<0.02) and aberrant crypt foci (p<0.007) in the colon and the amount of global DNA methylation (p<0.04) and activity of DNA methyltransferase (DNMT) (p<0.003) in the liver. In each case, there were more aberrant crypts and aberrant crypt foci, a relative DNA hypomethylation,
and increased activity of DNMT in the rats fed 50 μg As/g compared to those fed 0.5 μg As/g. The same phenomenon, an increased
number of aberrant crypts and aberrant crypt foci, DNA hypomethylation, and increased DNMT tended to hold when comparing rats
fed the diet containing no supplemental arsenic compared to rats fed 0.5 μg As/g. The data suggest that there is a threshold
for As toxicity and that possibly too little dietary As could also be detrimental.
The U.S. Department of Agriculture, Agricultural Research Service. Northern Plains Area is an equal opportunity/affirmative
action employer and all agency services are available without discrimination. 相似文献
9.
We hypothesized that in marginal thiamin deficiency intracellular alpha-oxoaldehydes form macromolecular adducts that could possibly be genotoxic in colon cells; and that in the presence of oxidative stress these effects are augmented because of decreased detoxification of these aldehydes. We have demonstrated that reduced dietary thiamin in F344 rats decreased transketolase activity and increased alpha-oxoaldehyde adduct levels. The methylglyoxal protein adduct level was not affected by oral glyoxal or methylglyoxal in the animals receiving thiamin at the control levels but was markedly increased in the animals on a thiamin-reduced diet. These observations are consistent with our suggestion that the induction of aberrant crypt foci with marginally thiamin-deficient diets may be a consequence of the formation of methylglyoxal adducts. 相似文献
10.
Based on the geometry of the colon mucosa, we built a model to compute the oxygen supply, the oxygen diffusion across the interstitial matrix, and the oxygen consumption by cryptal and stromal cells. By using an iterative algorithm, we have been able to solve a set of discretized (time and space) oxygen balance equations and determine the three-dimensional distribution of pO2 in the mucosa. Although significant longitudinal and radial pO2 variations were found, cells appeared to operate at their maximum respiratory capacity, regardless of their location in the tissue. The estimated oxygen extraction fraction was 47%, while the capillary oxygen permeability was 1.57×10−5 cm m s−1. We concluded that cellular metabolism in normal colon mucosa is not limited by oxygen supply, thus prompting the idea that oxygenation does not determine the characteristic microenvironments occurring along the normal Lieberkhün crypts. In an extended model, simulation of an aberrant crypt focus (ACF)—the earliest stage in the adenomatous polyp-carcinoma sequence—showed instead that respiratory activity decreased when the capillary array symmetry is disrupted due to the ACF growth. A unified explanation about the alternative of a hypoxic-independent and/or a hypoxic-dependent early angiogenic response associated to the development of ACF is proposed. 相似文献