Showing papers on "Crypt published in 1978"

Cell population kinetics in the epithelium of the colon of the male rat

Abstract: The present study was undertaken in order to try to define some of the kinetic parameters in the colonic mucosa of normal Wistar rats Preliminary observations showed considerable morphological differences in the mucosa from site to site along the length of the colon In particular the height of the crypts (measured in cells) was variable In addition labelling index studies demonstrated dramatic variations in the distribution of labelling along the length of the crypts from site to site in the bowel A single site in the descending colon was selected for more detailed study using a stathmokinetic agent, vincristine, and the continous labelling technique with tritiated thymidine The results of these investigations suggest that there exists at the base of the crypt a subpopulation of cells cycling more slowly than the cells in the rest of the proliferative compartment Growth fraction appears to fall with rising cell positions within the crypt

Cell population kinetics in the mucosal crypts of the descending colon of the mouse.

Abstract: In the present study we have used a variety of techniques in order to investigate cell proliferation in the mucosal crypts at a strictly defined site in the descending colon of the mouse. The mean crypt length was 31.1 cells, and the mean crypt circumference 22.5 cells, giving a total crypt population of about 700 cells. The corrected mitotic index for the whole crypt column was 1.33%; the labelling index was 11.7% with peak values of about 27% occurring at the bottom of the crypt. Metaphase accumulation following vincristine showed that the birth rate in the whole crypt was 26.5 cells/1000 cells/h. From a consideration of cumulative mitotic index and cumulative birth rate a mitotic duration of 0.39 h was obtained. Analysis of FLM data gave a cell cycle time for the whole crypt of 15.5 h: from FLM data and observed labelling index a growth fraction for the whole crypt of 29% was obtained. Analysis of FLM data for individual cell position groups at different sites within the crypt indicated that the mean cell cycle time showed little variability and was about 15 to 16 h, whereas the duration of DNA synthesis fell with rising cell positions. Growth fraction too appeared to fall with rising cell position within the crypt.

The effect of single and of multiple doses of prednisolone tertiary butyl acetate on cell population kinetics in the small bowel mucosa of the rat.

Abstract: The effect of single and of multiple doses of prednisolone upon cell population kinetics in the rat jejunal crypt was investigated, using autoradiography and stathmokinetic techniques with vincristine. Single injections of prednisolone (2.5 mg/kg body weight) induced a depression in both flash thymidine labelling and mitotic indices; this change was shown to be due to a decreased cell production rate. Recovery of these proliferative indices occurred over seven days after injection; measurement of crypt size parameters showed a transient decrease in crypt population.

Stereomicroscopic examination of stained rectal biopsies.

Abstract: The normal mucosal surface morphology in the rectum has been described by investigation of 15 rectal biopsies using a semimacroscopic technique. The structures of the mucosal surface were rendered visible by staining the biopsies as whole mounts with Alcian Green. A regular pattern of the crypt openings was found, and the goblet cells were observed in and just around the crypt openings. The density of crypt openings was calculated as the number of crypt openings per square millimetre (104 ± 23 openings per mm2, mean and S.D.). Histologic examinations of the same biopsies were performed, and the density of crypt tubules was calculated from serial, horizontal sections (130 ± 34 tubules per mm2, mean and S.D.). The ratio of crypt openings/crypt tubules was 1:1.25, indicating some branching of the mucosal glands in the rectum.

Influence of restricted diet on epithelial renewal and maturation in the mice jejunum.

Abstract: It has been known that the intestinal epithelial cell is characterized by a rapid cell turnover and by a gradient of differentiation from crypt to villas. The present study was undertaken to clarity the effect of diet on the migration and the maturation of the intestinal epithelial cells. The transit time from the crypt to the extrusion zone at the villus tip was determined with tritiated thymidine. To study the maturation of the cells the distribution of the terminal digestive enzymes, maltase [EC 3. 2. 1. 20] and leucylnaphthylamidase [EC 3. 4. 1. 1], along the villus and crypt was analyzed quantitatively. And total activities of the same enzymes were assayed also in the mucosal homogenates. It was observed that the decrease in the migrating speed of villus cells was brought by energy restriction and the decrease in the migrating speed was associated with an increase of the enzyme activities in the upper zone of villus. And the result was that the intestinal epithelial cells which decrease in migrating speed by dietary restriction become more mature on the upper villus than those with unrestricted control.

Properties of 3-hydroxy-3-methylglutaryl-coenzyme A reductase in villous and crypt cells of the rat small intestine.

Abstract: Some properties of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase in microsomes of villous and crypt cells from the jejunal and ileal epithelia of rats fed commercial pellet were studied. The optimum pH of the microsomal reductase from villi and crypts was 7.0_??_7.2 and the Km for HMG-CoA was 41.7μM. The reductase specifically required dithiothreitol for its activity. The activity was higher in ileal populations than in the jejunum. Responses of the reductase in the villous fraction to feeding cholesterol and taurocholate in combination or cholestyramine resembled those observed in crypt cells. Thus, the properties of microsomal HMG-CoA reductase in villous and crypt cells from the small intestine are similar each other, and they are possibly the same enzyme.

The influence of thyroid and testicular hormones on globule leucocytes in the rat duodenal crypt epithelium

Abstract: The globule leucocyte is a cell with a wide distribution in the digestive, respiratory, biliary, urinary and genital tract epithelia of homeotherms. It occurs in the crypts of the rat small intestine and within the epithelium on the villous bases but not on the remainder of the villi. A characteristic feature of this cell is the presence of acidophilic cytoplasmic granules, 0.5 to a few mm in diameter. The nucleus resembles that of intraepithelial intestinal lymphocytes. In this investigation, a quantitative study was made of the effect of thyroidectomy and/or castration on the number of globule leucocytes in the duodenal crypts of immature and adult rats. In sham-operated rats, globule leucocytes were rare, occurring with a frequency of 1 or 2 per 1,000 epithelial cells. After thyroidectomy, they increased to 14-20 per 1,000 epithelial cells. Castration did not influence the number of globule leucocytes but resulted in an increase in the number, size and acidophilia of their cytoplasmic granules. In immature rats, but not in adults, castration combined with thyroidectomy enhanced the effect of thyroidectomy, increasing globule leucocyte number to 32 per 1,000 epithelial cells. Treatment of thyroidectomized-castrates with thyroxine, initiated 38 days after operation, reduced the crypt globule leucocyte population to normal, whereas treatment with testosterone did not. Growth hormone failed to influence the elevated number of globule leucocytes in thyroidectomized rats, suggesting that this action of thyroxine was not mediated via an influence on growth hormone release. Because of their similar nuclear morphology, intraepithelial crypt lymphocytes were also counted and there was no obvious relationship in the fluctuations of these two cell populations. It is suggested that the greater number of crypt globule leucocytes in thyroid deficiency may reflect changes in the intestinal secretory immunoglobulin system and this is being investigated, beginning with a study of the distribution of IgE.

Cell surface galactosyltransferase in mitosis, differentiation, neoplastic transformation and metastases

Abstract: Several glycosyltransferase activities, usually associated with intracellular membranes, were detected as cell surface membrane activities of the undifferentiated intestinal crypt cell, fetal intestinal cell, and the chemically induced intestinal tumor cell. In contrast, the differentiated villus cell demonstrated only cell surface sialyltransferase activity. Subcellular fractionation of villus and crypt cells demonstrated a lateral membrane fraction of villus cells separable from Golgi membrane whereas crypt cell surface membrane had the enzyme features of Golgi membranes. These data suggest a similarity between crypt cell surface membrane and crypt Golgi membrane. In addition, crypt cells, fetal intestinal cells, and tumor cells were found to be preferentially agglutinated by Concanavalin A (Con A). Exposure of these cells to Con A appeared to specifically reduce galactosyltransferase. Virally transformed tissue culture cells and animal tumor cells were shown to have a number of cell surface glycosyltransferase activities but to release only galactosyltransferase into the medium or serum. A specific role is proposed for this enzyme in cell adhesion, cell recognition, and metastatic processes.

The influence of rat age on crypt cell kinetics after partial resection of the small intestine.

Abstract: Any investigator assumes a priori that data derived from studies utilizing different ages of animals cannot be rigorously compared. Several papers dealing with the compensatory response to intestinal resection have utilized animals of quite different age and weight and rarely has the stock been the same (see Table I). This study was designed to test the premise that the number of crypts per small intestine varies with animal weight and that indigenous crypt number will influence some features of the compensatory response of the crypt and villus cell population normally seen after intestinal resection (1-3).A reduction in the total villus and crypt cell population by surgical removal of a portion of the intestine is soon followed by compensatory responses, the most prominent being alteration in values for several parameters of mucosal cell kinetics (2, 3).The compensatory response to partial resection was assessed by the determination of (a) proliferative activity per crypt, (b) proliferative activity per ...

The effect of hyperthermia on the radiation response of crypt cells in mouse jejunum

Abstract: The effect of hyperthermia and/or gamma-radiation on the survival of intestinal crypt cells was studied in BDF sub 1 mice using a microcolony assay. Hyperthermia treatments, which in themselves caused no detectable cell lethality, inhibited the capacity of crypt cells to repair sublethal radiation damage. In addition, heat applied either before or after single radiation exposures potentiated lethal damage to crypt cells; the degree of enhancement was dependent on the time interval between treatments. At the levels of heating employed, DNA synthesis in the intestinal epithelium was significantly reduced immediately following exposure, but returned rapidly to normal levels. No further disturbances in cellular kinetics were observed for up to 10 days after heating.