Showing papers on "Crypt published in 1971"

Epithelial cell migration in the alimentary mucosa of the suckling pig.

Abstract: SummaryThe small intestinal villus epithelium in day-old pigs was replaced in 7-10 days, while that in 3-week-old pigs was replaced in 2-4 days. Decreased replacement time with age was associated with an increase in crypt depth and a decrease in villus length. Epithelia in the large intestine were also replaced more slowly in day-old than in 3-week-old pigs. Squamous epithelia in esophagus and stomach were replaced at similar rates in both age groups.

Intestinal crypt survival and total and per crypt levels of proliferative cellularity following irradiation: single x-ray exposures

Abstract: A radiation survival curve for intestinal crypts has been obtained. It is characterized by a D0 of 330 R and n of 10. Crypt survival is quantitatively similar for assays performed at 3 and 4 days following irradiation, although crypt size varies considerably during this interval. An as yet unexplained discrepancy exists between the crypt survival curve obtained experimentally and that predicted from crypt cell survival parameters and compartment size. Proliferative crypt cells appear to constitute the intestinal stem cell compartment. Recovery in terms of cellularity occurs even following exposures as high as 1400 R. It seems critical for 5-day survival of the animal that proliferative cellularity reaches some requisite level by day 3 following exposure; later increases in cellularity are not reflected by increased 5-day survival. It appears from this that crypt survival is an important feature with respect to 5-day survival of the irradiated animal.

Renewal of the epithelium in the descending colon of the mouse. III. Diurnal variation in the proliferative activity of epithelial cells

Abstract: The rate of proliferation of epithelial cells in the descending colon was investigated in four groups of adult mice sacrificed one hour after injection of 3H-thymidine respectively at 04:00, 10:00, 16:00 and 22:00 h of the day. Semithin (1 μ) Epon embedded sections of the colon were radioautographed after staining with periodic acid-Schiff and iron-hematoxylin. Measurement of the number of mitoses as well as the labeling indices show a diurnal variation in the rate of proliferation of both vacuolated and mucous cells. The peak of mitotic activity in both cell types seems to be around 12:00–13:00 h and the nadir around 20:00–22:00 h. In the vacuolated-columnar cell line, the rate of proliferation of the poorly differentiated cells at the base of the crypt is not much influenced by diurnal variation, while that of the more differentiated cells located higher up is. Mucous cells, which are believed to originate in the poorly differentiated vacuolated cells in the lower portion of the crypt, are also strongly affected. Therefore, the more differentiated cells are, the more susceptible they are to diurnal variation in mitotic activity. The number of epithelial cells lining the crypt varies throughout the day in a similar manner as the rate of cell proliferation. A slight daily variation is also noted in the number of cells in the surface epithelium. These variations are accounted for by a delayed effect of the population pressure resulting from the mitotic peak. The numbers of vacuolated-columnar and mucous cells vary like those of the whole epithelial population, while argentaffin cells fluctuate more widely. In any case, the three main cell lines of the descending colon of the mouse are influenced to some extent by diurnal variations.

Intestinal crypt survival and total and per crypt levels of proliferative cellularity following irradiation: age response and animal lethality.

Abstract: Hydroxyurea was employed as a synchronizing agent for proliferative intestinal crypt cells in vivo. The drug was found to kill in excess of 90% of S-phase cells, and to block the G1 to S transition...

35 sulphur uptake in the mucosa adjacent to carcinoma of the large intestine.

Abstract: A histochemical study of the epithelial mucosubstances was performed on surgical specimens from cases of carcinoma of the large intestine. Thein vitro uptake of sulphur was investigated in the same material by organ culture and autoradiography. Pieces of normal mucosa at a distance from the tumour area and of apparently normal mucosa surrounding the tumour were taken in every specimen and the findings compared. The distribution of mucosubstances in normal colon and rectum, called here the ‘normal mucous pattern’, shows a predominance of sulphated mucosubstances occupying from the lower half to the whole of the crypt. Non-sulphated acid mucosubstances are usually present in the upper part of the crypt. In the surface epithelium both types of acid mucin are usually present. This ‘normal mucous pattern’ changes both qualitatively and quantitatively in the mucosa adjacent to the tumours, despite its being morphologically normal. This area may be termed the ‘transitional mucosa’; in it, a gradual decrease of sulphated material was observed together with an increased amount of a non-sulphated acid mucosubstance, most probably a sialic acidcontaining one. Studies with sulphur show an uptake of the isotope along the crypt and surface epithelium in the normal, compared with the findings in ‘transitional’ mucosa where either the isotope is present only in the surface epithelium, or no uptake is observed either in surface epithelium or in crypt cells. An interpretation and practical application of these findings are discussed.

The origin and kinetics of goblet cells in the human jejunum during irradiation

Abstract: The data obtained from multiple serial biopsies of the jejunal mucosa of patients receiving post-operative irradiation have been analysed. These have demonstrated an inverse relationship between mitotic activity in the crypt and the number of goblet cells. From this and other evidence the conclusion has been reached that a single stem-cell system in the mucosal crypt gives rise to both epithelial and goblet cells and that the latter are a product of differentiation and are not derived from an independent stem-cell population.