Showing papers on "Crypt published in 1975"
TL;DR: By 21 days the number of crypts in the small intestine of the mouse had increased steadily to levels approaching normal, and the mechanism of increase in crypt number was by budding and fission of repopulated crypts which had become larger than normal.
Abstract: Following 1600 R of X-rays there was a reduction in the number of crypts in the small intestine of the mouse by 77% as measured 5 days later. However, by 21 days the number had increased steadily to levels approaching normal. The number of villi did not change following irradiation. The mechanism of increase in crypt number was by budding and fission of repopulated crypts which had become larger than normal. Some aspects of crypt organization are discussed.
110 citations
TL;DR: Support is added to the hypothesis that the small intestinal crypts contain a sub-population of stem cells that are distinct from the proliferative cells, as well as the regeneration patterns for cryptogenic and proliferative Cells over the first 4 days after irradiation.
Abstract: A dose of 900 rad gamma-rays to mice reduces the number of cryptogenic cells (those capable of crypt regeneration) per small intestinal crypt from about 80 to about 2 per surviving crypt. The surviving cells repopulate the crypt, the estimated cell-number doubling-time being about 24 hours, and on the fourth day after irradiation their numbers are still slightly below normal. The regeneration patterns for cryptogenic and proliferative cells differ significantly over the first 4 days after irradiation. The numbers of proliferative cells fall initially and remain low while the cryptogenic cells are increasing in number. The low levels persist for the first 1-5--2 days, after which there is a rapid rise in proliferative cells per crypt with a significant overshoot on the third day and a peak on the fourth day. The number of proliferative cells per crypt in control animals is about twice the number of cryptogenic cells. This ratio is on average 12 after irradiation (days 1--4). These data add support to the hypothesis that the small intestinal crypts contain a sub-population of stem cells that are distinct from the proliferative cells.
93 citations
TL;DR: Proliferation and migration of cells in the vacuolated-columnar and mucous cell lines were studied in the descending colon of adult female mice given a single injection or a continuous infusion of 3H-thymidine and killed at various intervals from one hour to 12 days.
Abstract: Proliferation and migration of cells in the vacuolated-columnar and mucous cell lines were studied in the descending colon of adult female mice given a single injection or a continuous infusion of 3H-thymidine and killed at various intervals from one hour to 12 days. This investigation was carried out using one μm-thick Epon sections which were radioautographed after staining with the periodic acid-Schiff technique and iron-hematoxylin.
In the normalized crypts with ten equal segments, labeled vacuolated cells at one hour after injection of 3H-thymidine were encountered in the lower four segments and in decreasing numbers in segments 5 through 7. From the percent labeled cells in segments of the crypt, the birth rate and fluxes of cells were computed. Moreover, it was found that a cell in the vacuolated-columnar cell line would undergo three mitotic cycles on the average from its birth at the cryptal base to its extrusion from the surface; of these three cycles, the last one which took place from segment 3 to segment 7 appeared to be a changeover from dividing cells to non-dividing cells, in accordance with the “slow cut-off” model of Cairnie et al. ('65b).
Mucous cells located in segments 1 through 6 of the crypt were capable of incorporating 3H-thymidine and thus capable of undergoing mitosis. However, the rate of turnover of mucous cells based on proliferative rate was found to be much lower than the rate of turnover of mucous cells based on the transit time in the non-dividing segments of the crypt. Since there was a concomitant overproduction of cells in the vacuolated-columnar cell line and some morphological similarity between vacuolated cells and newly formed mucous cells in the lower portion of the crypt, it was concluded that some vacuolated cells would give rise to mucous cells. This putative transformation occurred in the lower four segments of the crypt.
Mucous cells which were formed by transformation would migrate upward along the cryptal wall and accumulate more mucus in the theca; in doing so, they would undergo two divisions, on the average, before they became non-dividing mucous cells.
In ascending the cryptal walls, both vacuolated-columnar cells and mucous cells appeared to migrate at a similar speed; they moved much slower at the base of the crypt and accelerated toward the upper portion of the crypt, but they migrated at a constant speed in the non-dividing segments of the crypt.
85 citations
TL;DR: The dose survival curve for clonogenic jejunal crypt cells appears to bend continuously until doses of at least 1100 rad, which suggests that a proportion of cells has a large capacity for repair of sublethal injury and that the survival curve is better described by a quadratic 16 than a multitarget function.
Abstract: The dose survival curve for clonogenic jejunal crypt cells appears to bend continuously until doses of at least 1100 rad. This suggests that a proportion of cells has a large capacity for repair of sublethal injury and that the survival curve is better described by a quadratic16 than a multitarget function. Repair of sublethal injury is dose-dependent. Quantitative estimates of repair per fractionation interval, expressed as (D N -D L (N-1) , when related to size of the dose/fraction, suggest that the repair capacity of most jejunal crypt cells may not be appreciably different from that of the cells of many other tissues. After low doses ( There appears to be some extra sparing of the crypt cells due to repair of sublethal damage even when doses/fraction of 200 rad or less are further fractionated. Determining accurately the dose below which repair is maximal, and all cell killing results from “single-event” nonrepairable injury, is difficult using present assays. Regeneration of surviving jejunal crypt cells is rapid after radiation injury. Its onset and rate may depend upon degree of injury (size of dose), and is probably facilitated by lengthening the fractionation interval, even if the overall treatment time is unchanged. No general formula can be applied to relate number of dose fractions and treatment duration to the total dose needed for an iso-effect in jejunal mucosa. Thus, the NSD formula,17 for example, should not be considered relevant to the response of intestinal mucosa to multifraction radiation.
77 citations
TL;DR: It was concluded that both villous and crypt regions contribute to the secretion of water and electrolytes (sodium, chloride and bicarbonate ions) during cholera.
63 citations
TL;DR: The findings suggest that intestinal drug metabolism is localized primarily in upper villous cells of duodenal mucosa, that cytochrome P-450 is synthesized in maturing epithelial cells as they migrate to the top of the mucosal villus and that this process is critically dependent on dietary iron.
49 citations
Journal Article•
TL;DR: It is concluded that these observations do not support the hypothesis that increased cell shedding from the top of the villus stimulates increased cell production in the crypts of Lieberkuhn.
Abstract: Rats were starved for 3 days, then either allowed access to food or continued in starvation. The following measurements on the upper jejunum were made on groups of refed and starved rats at nine time intervals after refeeding: villus height, crypt depth, crypt/villus ration, rate of cell production per crypt, and number of epithelial cells shed per villus in 5 minutes. Villus height increased 2 hours after refeeding, while crypt depth changed less dramatically. Crypt/villus ratio was unchanged. The number of shed epithelial cells per villus was reduced below the starved level for 4 hours after refeeding, and did not rise significantly above the starved level until 9 hours; the rate of cell production was not significantly increased until 12 hours after refeeding. No evidence for a reserve of cells in G2 was found, and the 3 hour lag between the rise in cell shedding and the increase in cell production would probably not give enough time for cells in G1 to pass through S and G2. It is concluded that these observations do not support the hypothesis that increased cell shedding from the top of the villus stimulates increased cell production in the crypts of Lieberkuhn.
43 citations
TL;DR: The results suggest that the major effect of cholera toxin was on villus cells rather than crypt cells and this was due to the greater accessibility or binding capacity of the villus cell to luminal cholERA toxin.
40 citations
TL;DR: Autoradiographic studies and scintillation counting of crypt material after pulse labelling with 3H‐thymidine showed that during continuous irradiation with 290 rads/day a reduced proliferative activity is present in the crypts of rat small intestine after 1 day of irradiation and of normal activity during the remaining period (5 days) irradiation.
Abstract: Autoradiographic studies and scintillation counting of crypt material after pulse labelling with 3H-thymidine showed that during continuous irradiation with 290 rads/day a reduced proliferative activity is present in the crypts of rat small intestine after 1 day of irradiation and of normal activity during the remaining period (5 days) irradiation. After cessation of irradiation an increase in proliferative activity can be observed after 1 day of recovery. From the time (36-48 hr after starting of the irradiation) that the number of villus cells is reduced an expansion of the proliferation zone in the crypt was observed. Both effects last until 1 day of recovery after cessation of irradiation. The process of crypt cell maturation and of villus cell function has also been studied during and after continuous irradiation by micro-chemical enzyme analyses in isolated crypts and villi. It was found that the expansion of the proliferation zone in the crypt is accompanied by a decrease in activity of only those enzymes (i.e. non-specific esterases) which normally become active during crypt cell maturation. The activity of enzymes normally present mainly in the functional villus cells remained relatively unaffected by changes in crypt cell kinetics. A hypothesis of different regulation mechanisms of the proliferative activity in the intestinal crypt and a possible explanation of the different behaviour of various enzyme activities as a result of changes in crypt cell proliferation is discussed.
39 citations
TL;DR: The enlargement of the small intestine of mice during lactation is due, at least in part, to hyperplasia in the mucosal crypts and villi, and the turnover time of post‐mitotic cells on the villi changed.
Abstract: The enlargement of the small intestine of mice during lactation is due, at least in part, to hyperplasia in the mucosal crypts and villi. The number of cells per crypt increases by 130% and the cell production rate by 63% after 15 days of lactation. These parameters were measured from crypt squashes and sections using both double-label and PLM techniques. Neither the numbers of crypts and villi in the small intestine nor the turnover time of post-mitotic cells on the villi changed.
A number of factors appear to act in concert during lactation to trigger this increase in epithelial cell number in the small intestine. The experiments reported suggest a role for the increased quantity of food consumed by the lactating animal, for changing hormonal levels, and for the increased demands placed on the body by milk production.
38 citations
TL;DR: The effectiveness of S-2-(3-aminopropylamino)ethylphosphorothiotic acid (WR2721) to protect against 4 MeV X-irradiation was tested on the intestinal epithelium of the mouse and was found to be most effective when injected 15 min prior to irradiation.
Abstract: SIGDESTAD, C. P., CONNOR, A. M., AND SCOTT, R. M. The Effect of S-2- (3-aminopropylamino)ethylphosphorothioic Acid (WR-2721) on Intestinal Crypt survival I. 4 MeV X-Rays. Radiat. Res. 62, 267-275 (1975). The effectiveness of S-2-(3-aminopropylamino)ethylphosphorothiotic acid (WR2721) to protect against 4 MeV X-irradiation was tested on the intestinal epithelium of the mouse. The agent was found to be most effective when injected 15 min prior to irradiation. The protective agent increased the LDso(6) by 816 rads. This resulted in a dose-modification factor of 1.64. WR-2721 did not modify the inherent radiosensitivity of the intestinal crypts, but displaced the curve to the right by 758 rads. The total and per crypt cellularity in protected and unportected mice exposed to X-irradiation is described.
TL;DR: Data suggest that glycoprotein synthesis may be active in the undifferentiated crypt cells and that certain glycosyltransferases may serve as marker enzymes for cellular differentiation in the intestine.
TL;DR: The results of these studies indicate that both villus and crypt cells contain one of the important components required for the cyclic AMP-mediated secretory response, namely, a cholera enterotoxin and PGE1-sensitive adenylate cyclase activity.
Journal Article•
TL;DR: It is concluded that the crypt contains a minority population of cells at its base that are the true stem cells that will determine the response of the mucosa to therapeutic agents and play a dominant role in mechanisms controlling cell proliferation.
Abstract: The proliferative organisation of the crypts of the small intestine is considered with special reference to the existence, location and numbers of stem cells. It is concluded that the crypt contains a minority population of cells at its base that are the true stem cells. These cells provide an input of cells for the larger proliferative compartment higher up the crypt. The presumptive stem cells may be pluripotent and produce Paneth, goblet and columnar cells. They are probably also the cells which are capable of regenerating the crypt after X-ray depopulation. Radiobiological experiments indicate that the number of cryptogenic cells is less than 80, while the results of several experiments on the kinetics of the cell populations indicate that the number of stem cells is about 20. The stem cells are located in the Paneth cell zone of the crypt, and are apparently passing through the cell cycle at about half the speed of the proliferative cells. It is these vital stem cells that will determine the response of the mucosa to therapeutic agents, probably play a role in carcinogenesis and play a dominant role in mechanisms controlling cell proliferation.
TL;DR: The crypt and villous cells have very different radiosensitivities when histological criteria are used to estimate, for example, cell death, and this difference in radiosensitivity seems to be unrelated to the capacity of the cells to rejoin the main fraction of radiation-induced single strand breaks in DNA.
Abstract: A sensitive method has been developed for the estimation of DNA strand breaks in the proliferating crypt cells and the differentiated villous cells of the small intestine of the mouse. The method is based on the observation that the rate of denaturation of DNA to single strands in alkali is increased after irradiation, the interpretation being that this effect is due to DNA strand breaks. Various tests and developments of the method, when applied to an in vivo situation, have been made. Using whole-body $sup 60$Co gamma irradiation (300 to 2000 rad), the yield of breaks induced per rad and the kinetics of their rejoining in vivo were found to be very similar in the crypt and villous cells. Most DNA strand breaks seemed to be rejoined within 30 min. In contrast with these findings, the crypt and villous cells have very different radiosensitivities when histological criteria are used to estimate, for example, cell death. This difference in radiosensitivity thus seems to be unrelated to the capacity of the cells to rejoin the main fraction of radiation-induced single strand breaks in DNA. (auth)
TL;DR: The influence of nerve stimulation and sham‐stimulation on the mitotic rate in epithelial cells lining the crypts of Lieberkühn in the jejunum of anaesthetized rats was studied.
Abstract: The influence of nerve stimulation and sham-stimulation on the mitotic rate in epithelial cells lining the crypts of Lieberkuhn in the jejunum of anaesthetized rats was studied. Administration of the anaesthetic and opening the abdominal cavity was without significant effect on the crypt cell mitotic rate. However, externalizing a loop of jejunum and applying sham-stimuli to its mesenteric nerves resulted in a significant decrease in the crypt cell mitotic rate in that loop. Application of electrical stimuli to the mesenteric nerves of another externalized jejunal loop resulted in a significant increase in the mitotic rate in the crypt cells of that segment. Similar acceleration of crypt cell proliferation by electrical stimuli applied to mesenteric nerves was also seen in chemically sympathectomized rats.
TL;DR: Cell kinetics in the jejunal crypt of the male Wistar rat were studied using autoradiographic techniques with tritiated thymidine and a stathmokinetic technique with vincristine to derive migration rate and cell kinetics values.
Abstract: Cell kinetics in the jejunal crypt of the male Wistar rat were studied using autoradiographic techniques with tritiated thymidine and a stathmokinetic technique with vincristine. The migration rate measured by following the movement of the 50 % peak on the labelling index distribution curve with time after injection of tritiated thymidine gave a value of 1.43 ± 0.14 (SE) cell positions per hour, compared with a value from a cumulative birth rate of 1.78 cell positions per hour.
The crypt column length was 32.9 ± 0.2 cells and the column count was 22.3 ± 0.2. This measurement gave a total crypt population of 734 cells, compared with an estimate of 650 ± 6 from direct observation of squashed, microdissected crypts. In each crypt 22.5 ± 0.5 mitoses were present, and the crypt cell production rate was 32 cells per crypt per hour; this latter value was confirmed using two independent techniques.
The crypt growth fraction calculated from the durations of phases of the cell cycle and the labelling index was 0.62. A value of 0.61 was found from the labelling index distribution curve. As assessed from crypt squashes, there were 403 proliferating cells per crypt.
TL;DR: Electron microscopic examination of samples from various regions of the rat small intestine was carried out to estimate the number of mitochondria in the epithelial cells and the errors involved in extrapolating these counts to the whole cells were estimated.
Abstract: Electron microscopic examination of samples from various regions of the rat small intestine was carried out. The number of mitochondria in the epithelial cells was estimated. The counts were made in sections of cells cut along their longitudinal central plane. The errors involved in extrapolating these counts to the whole cells were also estimated. The average mitochondrial number per cell section was 21 in the lower third of the crypts, it gradually increased in the mid and upper thirds and reached about double, 42, at the villus base. The known forms of dividing mitochondria were identified in the mid and upper third of the crypts. The counts remained around 42 along the epithelium of the villi. Crypt cells are continually produced in the lower crypt; these cells migrate to the villi while differentiating into nonproliferative absorptive cells. After inhibiting mitosis by methotrexate, this migration continued (Altmann, '74) and mitochondrial division persisted. In segments of the jejunum isolated surgically from the functional intestine for three weeks, mitosis and cell migration continued, but no evidence of mitochondrial duplication was found. Each mitochondrion probably undergoes a division as the crypt cells migrate from the mid-crypts to the villus. As a result, the villus epithelial cells contain double numbers of mitochondria. It appears that the mitochondrial division is not directly related to mitosis and is elicited by a stimulus present only in the functional intestine.
TL;DR: The perturbed cellular kinetics of the duodenal crypt following a single injection of hydroxyurea (HU) have been simulated using matrix algebra and the overall recovery process results in a crypt which temporarily is larger than control and produces villi cells at a rate which is faster than the control.
Abstract: The perturbed cellular kinetics of the duodenal crypt following a single injection of hydroxyurea (HU) have been simulated using matrix algebra. Following the direct effects of HU (S-phase cytotoxicity and a G1/S block) the crypt cell kinetics undergo several alterations. Previously documented alterations include: (1) a temporary partial synchronization of the surviving cells, (2) a shortening of the cell-cycle transit time, and (3) recruitment of normally non-proliferating cells into active proliferation. These conclusions have been extended by constructing several different complex but theoretically possible recovery models and the validity of each of these models has been evaluated by simulating the following biological data: the number of cells in the S and M-phase of the cell cycle, total viable cells per crypt, and the per cent labeled mitosis and the number of labeled cells following 3H-TdR injections at 9 and 21 hr after HU treatment. The model which showed visually the best overall agreement with all sets of the data was chosen as "most probable' and leads to the following interpretations. Immediately after the end of the HU block (i.e. 5 hr after HU injection) the modal cell-cycle transit time is reduced to 8 hr. By 17 hr after HU, the modal transit time is increased to 10 hr. Repopulation of the proliferating compartment, i.e. restoration of the proliferating compartment back to the control value, occurs between 12 and 17 hr after HU injection and probably consists of both recycling of the proliferating cells (i.e. they do not progress up into the non-proliferating compartment) and recruitment of the non-proliferating cells into active proliferation. Also, the rate at which the non-proliferating cells move onto the villi is reduced temporarily. The overall recovery process results in a crypt which temporarily is larger than control and produces villi cells at a rate which is faster than the control. The time when the crypt size and villus cell production rate return to normal cannot be established using the available data.
TL;DR: The structure of the fowl's intestinal crypt is very similar to that described for the mammal and the results are discussed in relation to previous histochemical studies.
Abstract: The fine structures of the development and maturation of intestinal chief cells from the duodenal crypts of the fowl has been described in detail. Three areas within the crypt can be recognised: 1) the crypt base where cell division is frequent but cell development is minimal; (2) the mid-crypt region where rapid growth and development of the cells takes place; and (3) the zone of differentiation where final developments and functional maturation occurs. The structure of the fowl's intestinal crypt is very similar to that described for the mammals. The results are discussed in relation to previous histochemical studies.
TL;DR: The model has been developed by simultaneously simulating the following biological data: the per cent labeled mitosis (PML) curve, the number of labeled cells per crypt as a function of time following an injection of 3H‐thymidine, and the total number of cells per Crypt.
Abstract: Steady state crypt cell kinetics have been simulated using matrix algebra. The model crypt cell population is distributed through two proliferation compartments (P1 and P2) and a quiescent state (Q). Under steady state conditions half the daughter cells produced on completion of P1 enter G1 of P2 and half enter G1 of P1. Both P2 daughter cells enter Q. Cells in Q are non-dividing but retain the potential to divide. On completion of Q, cells lose the potential to divide and move up onto the villi. The model has been developed by simultaneously simulating the following biological data: (1) the per cent labeled mitosis (PML) curve, (2) the number of labeled cells per crypt as a function of time following an injection of 3H-thymidine, and (3) the total number of cells per crypt.
TL;DR: The correlation of DNA + RNA synthesis and enzymes involved in nucleotide synthesis was investigated and 5′-nucleoti-dase activity which is found to be localised ultrastructurally in the same place as alkaline phosphatase, interferes with the assay of thymidine kinase.
Journal Article•
TL;DR: The results indicated that villi and crypts elongate, and epithelial cell migration accelerates between 1 day and 6 months of age, and Epithelial replacement time seemed to increase with age of the chickens.
Abstract: Villous length, crypt depth, epithelial cell migration rate, and replacement time were studied by autoradiography of histologic sections of small intestine from normal chickens exposed to tritiated thymidine (3-H-TdR). The results indicated that villi and crypts elongate, and epithelial cell migration accelerates between 1 day and 6 months of age. Epithelial replacement time seemed to increase with age of the chickens. Replacement was nearly complete in the 1-day-old group of chickens 5 days after thymidine exposure. In contrast, at this same time, replacement was only approximately 75 and 50% complete in the 3-week-old and 6-month-old groups of chickens, respectively.
TL;DR: Direct morphometric estimation of the number of intestinal crypts per 10 mm length of jejunum, the total number of cells per crypt, and the number and volume of Paneth cells per Crypt was performed using Zenker-fixed, serially sectioned small intestines from adult BALB/c mice.
Abstract: Direct morphometric estimation of the number of intestinal crypts per 10 mm length of jejunum, the total number of cells per crypt, and the number of Paneth cells per crypt was performed using Zenker-fixed, serially sectioned small intestines from adult BALB/c mice. The mean volume of a crypt cell was estimated to be in the order of 6.6 plus or minus 0.1 times 10-4 mm-3, while the total volume of all cells in a single crypt was 1.833 plus or minus 0.02 times 10-1 mm-3. The cell population per crypt was 278 plus or minus 7 cells, of which 44 plus or minus 10 were Paneth cells. It was estimated further that 265 plus or minus 30 crypts per 10 mm length of jejunum contained 7.4 plus or minus 0.1 times 10-4 cells, including 1.2 plus or minus 0.24 times 10-3 Paneth cells. The volume of all crypt and Paneth cells per 10 mm length of jejunum was in the order of 49 plus or minus 1.2 and 8 plus or minus 1.8 mm-3, respectively. The volume of the tunica muscularis and the surface area of the crypt's lumina were estimated to be 33.5 plus or minus 2.2 mm-3 and 118 plus or minus 19 mm-2, respectively.
TL;DR: There is no difference in the post-mitotic age of cells at a similar level in the villus in adult and aged mice, although they are derived from stem cells of different ages.
Abstract: There has been much discussion whether ageing in a fixed post-mitotic cell is the same as ageing in a constantly renewing stem cell population. This can be tested by comparing cells from the crypts and different levels on the villus in the small intestine. We know from the work of Lesher’s group (1) that the transit time from crypt base to villus tip in the mouse jejunum is just over 50 hr in both 1-year-old and 2 1/2-year-old animals, of which about 6 hr is spent in the crypt. There is therefore no difference in the post-mitotic age of cells at a similar level in the villus in adult and aged mice, although they are derived from stem cells of different ages.