bluuebunny/crossref_metadata_2025_split huggingface dataset:
AUTORADIOGRAPHIC CONFIRMATION OF THE MITOTIC DIVISION OF EVERY MOUSE JEJUNAL CRYPT CELL LABELLED WITH 3H‐THYMIDINE
Authors: Burholt D. R. , Schultze B. , Maurer W. 
Published: May 2008

ABSTRACTThe question was investigated of whether for crypt epithelia of the jejunum of the mouse all cells labelled after a single injection of 3H‐TdR subsequently divide or whether cells exist in the crypt which synthesize metabolic DNA and, therefore, do not undergo division after labelling.A double labelling experiment was performed with a first injection of 3H‐TdR followed 1 hr later by an injection of 14C‐TdR. Then from double emulsion autoradiographs of isolated squashed crypts the number of 3H‐only, 14C‐only and double labelled cells and mitoses were counted.The double labelling produced a narrow, 1 hr wide sub‐population of 3H‐only labelled cells. This subpopulation of S cells completed its division before labelled cells were lost from the crypts by migration onto the villi. The results showed that this subpopulation of 3H‐only cells completely doubled within 3 hr and then remained constant through 6 hr. From this result it was concluded that every cell labelled after a single injection of 3H‐TdR divides.From the same autoradiographs the flow rate through the end of mitosis was measured. From the flow rate and the mitotic index a mitotic duration of 0·5 hr was determined. The agreement of this measured mitotic time with the value calculated from the labelling index, mitotic index and S duration is also strong evidence that every labelled cell divides.Both experiments show that the intestinal crypt does not contain cells synthesizing metabolic DNA.
ACTION OF HYDROXYUREA AND N‐CARBAMOYLOXYUREA ON THE CELL CYCLE OF TETRAHYMENA
Authors: Cameron I. L. , Jeter J. R. 
Published: May 2008

ABSTRACTAddition of a 50 mm dosage of hydroxyurea (HU) to growing cultures of the cilitate Tetrahymena pyriformis allows cell growth to continue but inhibits DNA synthesis, and inhibits cell division after a 20–30% increase in cell number. Higher concentrations of HU cause cell death. T. pyriformis strain differences exist in sensitivity to HU. No cytotoxicity selective to a specific phase of the cell cycle could be demonstrated.The inhibitory effects of HU are entirely reversed by removal of HU and this procedure can be used to induce cell cycle synchrony. Supplementing HU treated cells with deoxyribonucleosides relieves the inhibitory action of HU.Carbamoyloxyurea (COU) is a reactive intermediate of HU and its action on Tetrahymena appears to be similar to that of HU. Because of this similarity and because COU is more potent than HU we postulate that COU is responsible for the unique properties previously ascribed to HU.
TEMPERATURE EFFECTS ON THE KINETICS OF SPERMATOGENESIS IN THE MOUSE
Authors: Meistrich M. L. , Eng V. W. S. , Loir M. 
Published: May 2008

ABSTRACTThe kinetics of spermatocyte differentiation in adult mice was measured under normal conditions, during maintenance at elevated temperatures and following experimental cryptorchidism. For these measurements the development of 3H‐TdR labelled testis cells was followed by velocity sedimentation at unit gravity and the results were in agreement with those obtained by autoradiography. In the cryptorchid animals and those maintained at 32°C the kinetics of spermatogenesis during treatment was increased by at least 13% over control values. Smaller but significant increases in the kinetics of spermatogenesis were obtained at ambient temperatures of 28 and 30°C without any observable histological damage. The increased kinetics is believed to be a direct effect of temperature on testis cell development.
THE NORMAL TRANSPLACENTAL PASSAGE OF MATERNAL RED CELLS IN MICE
Authors: Holliday Jean , Barnes R. D. 
Published: May 2008

ABSTRACT 51Cr labelled red cells injected into pregnant mice were subsequently detected in peripheral blood of their progeny when examined in autoradiography. The fact that these labelled cells were seen in the offspring from five different strains of mice suggests that this transplacental passage is probably a ‘normal’ phenomenon.
ANALYSIS OF PROLIFERATION AND DIFFERENTIATION OF FOETAL GRANULOCYTE‐MACROPHAGE PROGENITOR CELLS IN HAEMOPOIETIC TISSUE*
Authors: Moore M. A. S. , Williams N. 
Published: May 2008

ABSTRACTAnalysis of in vitro colony formation in agar cultures of foetal haemopoietic tissues of eight mammalian species has shown that granulocyte‐macrophage progenitor cells are present in foetal liver, yolk sac, marrow and spleen in numbers approaching the incidence in adult marrow. Such characteristics as buoyant density, growth rate and differentiation served to distinguish foetal from adult colony forming cells (CFCs).Cell cycle analysis performed by exposing haemopoietic cells to high doses of tritiated thymidine in vitro showed that foetal CFC proliferation in species of short gestation (rabbit, rat, mouse) approached or exceeded that observed in adult marrow. In contrast, in species of long gestation (human, monkey, calf, lamb, guinea‐pig) a period of variable duration was observed when foetal liver CFCs entered a non‐cycling G0 or blocked G1 phase. In these species foetal liver CFCs were found to be proliferating actively early in gestation and following the non‐cycling phase again re‐entered a proliferative state associated with onset of active granulopoiesis in foetal marrow and possible migration of CFC from liver to marrow.These results indicate the existence of granulocyte‐macrophage progenitor populations displaying foetal characteristics and adapted to particular stages of haemopoietic development, a situation which closely parallels that reported for erythropoiesis.
PROLIFERATION OF LIVER EPITHELIA IN THREE‐WEEK‐OLD RATS
Authors: Schultze B. , Maurer W. 
Published: May 2008

ABSTRACTThe proliferative activity of liver epithelia in 3‐week‐old rats was studied auto‐radiographically using 3H‐thymidine. Only a single peak of labelled mitoses (late pro‐ to anaphases) at 7 hr was found in the per cent labelled mitoses curve after injection of 3H‐thymidine. A second peak at about 32 hr described by Post, Huang & Hoffman (1963) and Post & Hoffman (1964, 1965) as well as Grisham (1969) and a cycle time of about 22 hr derived from the distance between the two peaks could not be confirmed by the present work.According to the present experiments the cycle time of parenchymal liver cells in 3‐week‐old rats must range between 50 hr (with a growth fraction of 0·25) and 7·1 days (with a growth fraction of 1·0). The present results do not support the existence of a growth fraction of only 0·1 as assumed by Post et al. (1963).
PROLIFERATION KINETICS OF SHAY CHLOROLEUKAEMIA CELLS GROWN IN DIFFUSION CHAMBERS IN VIVO
Authors: Vilpo J. A. , Rytömaa T. 
Published: May 2008

ABSTRACTThe proliferation kinetics of Shay chloroleukaemia cells was studied by the labelled mitoses technique and some other methods. Detailed estimates of the phase durations of the cell cycle for proliferating cells were obtained using young, exponentially growing diffusion chamber cultures; estimates of kinetic parameters were also obtained for ‘old’ cultures and for local subcutaneous chloroma tumours. The results enabled determination of the growth fraction and the cell loss factor.Cell loss was found to be the dominant factor determining the growth rate of chloroleukaemia cell populations. The mechanism of cell loss was cell death. Some implications of these findings are discussed.
PREVENTION OF GRAFT VERSUS HOST REACTION BY INCUBATION OF LYMPHOID CELLS WITH A SPLENIC EXTRACT (NOT AFFECTING THE REPOPULATION OF THE HAEMOPOIETIC TISSUE)
Authors: Garcia‐Giralt E. , Morales V. H. , Bizzini B. , Lasalvia E. 
Published: May 2008

ABSTRACTAn alcohol extract of calf spleen possessing the in vivo characteristics of a lymphoid chalone has already been shown to prevent or to control the acute graft versus host reaction (GVHR) in lethally irradiated F1 recipients, when given respectively to the parental cell donors or to the F1 recipients. The present experiments demonstrate the efficacy of the incubation of the donor cells with this extract on the prevention of GVHR, and shows that it selectively inactivates cells responsible for it.
GRANULOPOIESIS AND CELL KINETICS IN CHRONIC MYELOID LEUKAEMIA
Authors: Gavosto F. 
Published: May 2008

ABSTRACTThe present study is an analysis of the kinetic data for chronic myeloid leukaemia derived from personal observations and cases reported in the literature. A comparison is made with the parameters for normal granulopoiesis and the growth pattern of the CML cell population discussed.
GROWTH OF STEM CELL CONCENTRATES IN DIFFUSION CHAMBERS (DC)
Authors: Quesenberry P. , Niskanen E. , Symann M. , Howard D. , Ryan M. , Halpern J. , Stohlman F. 
Published: May 2008

ABSTRACTThe growth in diffusion chamber (DC) of normal murine marrow and marrow separated by discontinuous albumin centrifugation was studied. The colony‐forming cells (CFC) assayed in soft agar, total cell counts and differentials were measured in the DC over a 19 day period after intraperitoneal implantation into CF1 mice. Growth of implants of normal marrow or fraction 3 (F3) in which CFC had been concentrated 1.7–3.9‐fold were compared at an initial cell concentration of 1 × 105. There was a good correlation between the number of CFC implanted with granulocyte production but not with macrophage production. When higher cell concentrations of normal unfractionated marrow were implanted growth was reduced as was recovery of CFC. In two experiments in which both CFU and CFC concentrations were measured there was a general correlation between the two.
CELL KINETICS IN THE SEBACEOUS GLANDS OF THE MOUSE. II. THE GLANDS DURING HAIR GROWTH
Authors: Hamilton E. , Howard A. , Potten C. S. 
Published: May 2008

ABSTRACTThe sebaceous glands of the mouse have been studied during hair growth initiated either spontaneously or artificially.The labelling index of the glands increases early in the spontaneous hair growth period. That of the epidermis is much lower and hardly changes during the growth period.After the initiation of hair growth by plucking, changes in cell proliferation in the sebaceous glands appear to follow those in the epidermis. The size of the gland and the number of cells in it also change after plucking. These variations can be related to the stages of hair growth.
FIBROBLAST CELL KINETICS IN THE PERIODONTAL LIGAMENT OF THE MOUSE
Authors: Zajicek Gershom 
Published: May 2008

ABSTRACTTwelve male mice were injected intraperitoneally with tritiated thymidine. Six were sacrificed after 1 hr and six after 7 days. The right manibular incisors were dissected, cut sagittally and dipped in liquid emulsion. In the exposed and stained slides, observation was restricted to the lingual side of the periodontal ligament. Cells were evaluated sagittally from the basal tooth end up to the distance of 5 mm and up to the depth of 100 μm in the direction of socket wall. Cell and grain count was evaluated separately in 100 × 10 μm rectangles, creating a two‐dimensional array onto which the periodontal ligament was mapped.The progenitor compartment extends up to the distance of 2400 μm from origin. Fibroblasts leaving this compartment migrate at different velocities, creating a velocity profile across the ligament. Adjacent to the socket wall cell movement is sluggish, whereas the fastest cell movement is exhibited by cells located 20–30 μm from the tooth.The existence of such a profile indicates a continuous renewal of intercellular bonds, consistent with a process of actively pulling the incisor from its socket by the migrating fibrocytes.
ARE CELL KINETIC DATA RELEVANT FOR THE DESIGN OF TUMOUR CHEMOTHERAPY SCHEDULES?*
Authors: Putten L. M. van 
Published: May 2008

ABSTRACTThe data on the importance of the application of information on cell kinetics for the success of tumour chemotherapy are critically reviewed. It is concluded that the data on cell sensitivity to drugs as affected by cell kinetic variables are as yet insufficient to permit the prediction of optimal dosage schedules for tumour therapy. More information is needed on differential responses and differential kinetic features of normal and malignant tissues. Optimistic views of cell kinetics as an easy answer to the problems of drug dosage schedule design are unjustified, but so is the disenchantment with cell kinetics as a fruitful approach. Much further work, especially on the drug sensitivity of cellular compartments in slow growing tumours, is needed before a complete evaluation of this tool is possible.
CELL PRODUCTION IN TUMOUR ISOGRAFTS MEASURED USING VINCRISTINE AND COLCEMID
Authors: Smith S. Rolf , Thomas D. Brynmor , Riches A. C. 
Published: May 2008

ABSTRACTVincristine sulphate has been found to be a more useful metaphase arrest agent than Colcemid. Metaphase accumulation, in isografts of a CBA mammary adenocarcinoma, was linear with time for at least 10 hr after vincristine administration and also independent of drug dose in the range 1–4 mg/kg body weight.A method for evaluating the cell production rate, in histological sections, of a cell population which forms a heterogeneous component of the tissue has been described. The percentage of each tissue component was determined using the Chalkley point count method and the mean number of metaphases in an arbitrary defined field were evaluated. Corrections for percentage composition and sectioning were applied and the cell production rate defined. This was found to be 15.8 ± 0.6 cells per 1000 cells per hour for this tumour.
THE RECOVERY FROM VARIOUS GRADATIONS OF CELL LOSS IN THE MOUSE SEMINIFEROUS EPITHELIUM AND ITS IMPLICATIONS FOR THE SPERMATOGONIAL STEM CELL RENEWAL THEORY
Authors: Keulen C. J. G. van , Rooij D. G. de 
Published: May 2008

ABSTRACTThe recovery of the seminiferous epithelium from cell loss has been investigated by counting the different kinds of A‐spermatogonia and resting primary spermatocytes in stages 7–8 of the cycle of the seminiferous epithelium at different intervals of time after injection of several dose levels of the alkylating agent Myleran.It was found that the decrease in total number of A‐spermatogonia is directly related to the logarithm of the dose of Myleran given. After all doses used, the total number of A‐spermatogonia starts to increase again between day 8 and 10. During the first part of the recovery, between day 8 and 16, the number of morphologically undifferentiated A‐spermatogonia increases, its maximal value being linearly dependent on the logarithm of the dose of Myleran given.Between day 24 and 32, the total number of A‐spermatogonia overshoots control values significantly only when large doses of Myleran are used, no overshoot having been observed at low doses. This suggests the existence of an all or none relationship between overshoot and cell loss. The number of resting primary spermatocytes never overshoots control values.The results are discussed as to the information they might give on the numerical behaviour of the stem cells of spermatogenesis.
THE CELL CYCLE TIME IN THE RAT JEJUNAL MUCOSA
Authors: Al‐Dewachi Huthaifa S. , Wright Nicholas A. , Appleton David R. , Watson Alexander J. 
Published: May 2008

ABSTRACTThe regional variation of the duration of cell cycle parameters was studied by constructing fraction of labelled mitoses curves at several levels in the jejunal crypt column of male Wistar rats. Prolonged Tc and Ts values were apparent only in the bottom eight cell positions, and these differences were shown to be significant compared with the remaining cell positions by analysing the data by the method of Gilbert (1972). Above cell position 8 the proliferating crypt cells showed effectively the same phase durations. For the whole crypt column Tc was 11.32 ± 0.14 (SE) and Ts 6.49 ± 0.10.Although variation in phase durations was confined to the basal portion of the crypt, the results essentially confirm the findings of Cairnie, Lamerton & Steel (1965a), and may be interpreted in terms of the slow cut‐off model. The demonstration of prolonged Tc values in basal cell positions confirms the presence of a longer cycling subpopulation of cells at the bottom of the crypt.
THE INFLUENCE OF INJECTED TRITIATED THYMIDINE ON THE MITOTIC CIRCADIAN RHYTHM IN THE EPITHELIUM OF THE HAMSTER CHEEK POUCH*
Authors: Møller Ulla , Larsen Jorgen K. , Faber Mogens 
Published: May 2008

ABSTRACTThe initial effect of an injection of TdR‐5‐3H (1 μCi/g body weight; 6 Ci/mmol) in the cheek pouch epithelium of the Syrian hamster is an increase in the mitotic index. The increase is observed 1–5 hr after injection, depending upon the time of day when the injection is given, and is followed by compensatory variations in mitotic index. This deviation from the normal circadian rhythm in the mitotic index appears to depend on the fraction of G2‐cells at the time of injection. The main effect is a shortening of tg2. No effect is observed after injection of non‐radioactive TdR or isotonic saline. The results of the present experiment emphasize that unexpected results may be obtained when using mitotic indices from animals labelled with 3H‐TdR, as well as the risks of using the PLM‐method in a partially synchronized system.
HAEMOPOIETIC STEM CELL (CFU) KINETICS IN THE CULTURE
Authors: Chertkov J. L. , Samoylina Nina L. , Rudneva Nina A. , Rakcheev A. M. , Kondratenko Nona F. 
Published: May 2008

ABSTRACTHaemopoiesis continued for over 2 months in organ culture of embryonal mouse liver, and haemopoietic stem cells (CFUs) capable of DNA‐synthesis were found in it all that time. Between the 10th and 40th day the number of stem cells in the culture was sustained in a steady state. Both in normal and in regenerating adult bone marrow haemopoiesis ceased within a short time in the culture. Induction of proliferation in haemopoietic stem cells combined with undamaged or improved micro‐environment resulted in a little better maintenance of CFUs in the adult bone marrow culture, The results are discussed in the light of current concepts of haemopoietic stem cell regulation.
CONTINUOUS LABELLING STUDIES ON MOUSE SKIN AND INTESTINE
Authors: Potten Christopher S. , Kovacs Laszlo , Hamilton Elizabeth 
Published: May 2008

ABSTRACTData are presented for changes in absolute radioactivity levels and labelling indices (LI) in three tissues: jejunum, colon and dorsal skin in the mouse during conditions of repeated (every 3 hr for 168 hr) 3H‐TdR (5 μCi) injections. The lengths of S and the cell cycle were estimated. The crypt and mucosal transit times were evaluated. There is a slowly cycling subpopulation in the crypt which may be the goblet cell precursors or a crypt stem cell population. The skin LI data cannot be fitted by a single straight line and the procedure of continuously handling or injecting the animals appears to result in a disturbance of the steady state. The liquid scintillation data for all samples showed some consistent and surprisingly large fluctuations and a clear deviation from linear uptake with increasing time.
COMPENSATORY GROWTH IN THE RAT TIBIA
Authors: Dawson Anne , Kember N. F. 
Published: May 2008

ABSTRACTWhen the proximal cartilage plate of one tibia of a rat is sterilized by radiation, compensatory growth occurs at the distal plate of the same bone. This growth is marked by small changes in the cell kinetic parameters and histology of the growth cartilage when compared with the distal cartilage plate in the unirradiated tibia. The changes are consistent with a delay in the maturation of the plate showing compensatory growth. Some possible mechanisms are considered, but the evidence available at present does not give decisive support to any particular theory.
DYNAMICS OF LEUKOCYTE MIGRATION INTO THE MOUSE ASCITES TUMOR
Authors: Lala P.K. 
Published: May 2008

ABSTRACTThere is a marked increase in the number of peritoneal leukocytes (lymphocytes, monocytes and granulocytes) during the growth of Ehrlich ascites tumor in mice. No local proliferation (as indicated by a labeling at 1 hr following a single 3H‐TdR injection) was observed in the normal peritoneal leukocytes or those in the ascites tumor, except for a very minor labeling of some tumor macrophages. Kinetics of peritoneal leukocytes was studied with a series of twelve injections of 3H‐thymidine (20 μCi every 8 hr) in normal mice as well as mice injected with 106 tumor cells i.p. 2 hr after the last 3H‐TdR injection. Animals were sacrificed at intervals up to 6 days. Granulocyte labeling in the blood as well as peritoneal space was near 100% in both groups of animals at all the intervals. Temporal changes in the labeling of lymphocytes (from 10% at 0 day to 22% at day 6), and monocytes (from 20% at 0 day to 57% at day 6) were identical in the blood and peritoneal space of normal animals, indicating a free exchange of cells between these compartments. Higher labeling indices than those in the controls were attained in the blood of tumor‐bearing hosts (viz 40% for lymphocytes and 80% for monocytes at 6 days) suggesting an increased turnover of these cells in the circulation. In addition, peritoneal mononuclear cells of tumor‐bearing mice showed even a higher labeling than those in the blood (viz 65% for lymphocytes and 92% for monocytes at 6 days) indicating a selective migration and/or retention of newly formed cells within the tumor, in contrast to a random migration into the normal peritoneal cavity. Furthermore, an identical labeling of macrophages to that of monocytes within the tumor indicated a short monocyte‐macrophage transition. The preferential accumulation of young mononuclear cells into the tumor may be of functional importance.
THE INFLUENCE OF GENETIC RESISTANCE ON CFU GROWTH KINETICS IN SPLEEN AND FEMUR
Authors: Buurman W. A. , Bruggen Ivonne VAN , Vos O. 
Published: May 2008

AbstractAn impaired colony formation of C57BL marrow cells transplanted into Ft (C57BL x CBA) mice was observed. In accordance with the literature this phenomenon has been designated as ‘genetic resistance’. Studies to elucidate the mechanism of the genetic resistance demonstrated that the multiplication phase of the CFU growth curve started in the semi‐isogeneic combination about 48 hr later than in the isogeneic combination. In the spleen this resulted in a lower ‘dip’. For the spleen as well as for the femur similar CFU doubling times were found during the multiplication phase when both transplantation combinations were compared. Furthermore the percentage of CFU in S‐phase (assessed with the 3H‐TdR suicide technique) during the first days after transplantation were similar in both combinations. When the spleen was removed 5–6 months before irradiation and bone marrow transplantation was performed the growth curve of parental CFU in the femur was identical with the growth curve of isogeneic CFU (no delay was observed). These results are discussed and a few theories explaining the observations are proposed.
CHANGES IN INTESTINAL CELL KINETICS IN THE SMALL INTESTINE OF LACTATING MICE
Authors: Harding J. D. , Cairnie A. B. 
Published: May 2008

AbstractThe 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.