bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Medium Osmolality On the Growth of Murine Continuous Marrow Cultures
Authors: Tennant G. B. , Bailey‐Wood R. , Dallimore C. M. 
Published: May 2008

AbstractThe effect of medium osmolality was examined in primary, continuous bone‐marrow cultures established from to strain mice. the non‐adherent cell population increased exponentially between weeks 2 and 5 and thereafter declined steadily. the number of CFU‐GM followed a similar pattern but showed greater variability. the optimum osmolality in 4 week old cultures was found to be about 345 mosmol/kg which was higher than the plasma osmolality (n= 20; mean = 323.3 mosmol/kg; range = 313–331). Maximum non‐adherent cell numbers were found at about 345 mosmol/kg (better than half‐maximum between 320 and 370 mosmol/kg). CFU‐GM numbers in the culture supernatant were maximal at about 355 mosmol/kg (better than half‐maximum between 320 and 400 mosmol/kg). an adherent layer developed over a wider range of osmolality than supported granulopoiesis (better than half‐maximum between 258 and 402 mosmol/kg). It was necessary to increase the osmolality of Fischer's medium in order to obtain maximum growth.
Use of A Mouse Chimaeric Model to Study Cell Migration Patterns In the Small Intestinal Epithelium
Authors: Wilson T. J. G. , Ponder B. A. J. , Wright N. A. 
Published: May 2008

AbstractThe pattern of cells migration in the small intestinal epithelia of a RIII/⇒ro C57BL/6J mouse aggregation chimaera is demonstrated using Dolichos biflorus agglutinin‐peroxidase (DBA) conjugate as a strain‐specific marker. Using serial tangential sections of heterogeneously stained villi and plotting the distribution of labelled/unlabelled cells with a drawing tube, and by three‐dimensional reconstruction with the aid of computer graphics, we show the migration pathway to be in tight cohorts of similar DBA‐peroxidase staining type, which move upwards in straight lines. There is little cell mixing either on the villus or along the crypt‐villus junctions. Our observations also show for the first time that a single crypt can feed cells to more than one villus. They also suggest that either cell loss is not confined to the villus tips but can take place from the villus sides, or that there is marked asynchrony of cell production between crypts.
Combined Effects of Aphidicolin and Retinoic Acid On Proliferation and Differentiation of Human Leukaemic (HL‐60) Cells
Authors: Chou R. H. , Chervenick P. A. 
Published: May 2008

AbstractThe relationships between replicative DNA synthesis and retinoic acid (RA)‐induced differentiation of human promyelocytic leukaemic (HL‐60) cells are evaluated with the use of Aphidicolin, a specific and reversible inhibitor of DNA polymerase alpha (α). Addition of a sublethal concentration of Aphidicolin (0.4 μM) in culture for 3 days suppresses DNA synthesis to a similar level of the resting stage (day 8) in control cultures. DNA synthesis is reactivated to the level observed in the growing stage of control cultures once Aphidicolin is removed after 3 days in culture. the level of DNA synthesis at the early stage of RA‐induction (day 3) is suppressed by only 17% when compared to control cultures. the inhibitory effect of Aphidicolin on DNA synthesis in both control cultures and RA‐induced cell cultures is similar. However, no reactivation of DNA synthesis is observed after removal of Aphidicolin on day 3 from RA‐induced cell cultures. Flow cytometric analysis of DNA content on day 3 reveals that cells accumulate in G1 and early S phases of the cell cycle after exposure to Aphidicolin with or without RA. of interest is the fact that, while Aphidicolin alone did not induce cells to differentiate, neither did it interfere with RA‐induced cell differentiation (the rate of RA‐induced cell differentiation in the presence of Aphidicolin is similar to that of RA‐treated cultures in the absence of Aphidicolin). These results suggest that the combined use of Aphidicolin and RA may inhibit leukaemic cell proliferation more effectively without causing severe cytotoxicity and without interfering with RA‐induced cell differentiation.
Oestradiol is effective in stimulating 3H‐Thymidine Incorporation But Not On Proliferation of Breast Cancer Cultured Cells
Authors: Jozan S. , Gay G. , Marques B. , Mirouze A. , David J. F. 
Published: May 2008

AbstractThe growth of numerous human oestrogen target cell lines is said to have been stimulated by oestradiol. We studied the action of this hormone on the growth of two human cancer cell lines originating from endometrium (GUS), and from breast (FAM). Oestradiol was inactive on endometrial cell multiplication as well as on their tritiated thymidine uptake, but in FAM breast cancer cells, we noticed a discrepancy between tritiated thymidine uptake and actual cell proliferation: there was a 40% increase in DNA precursor uptake, but no change in either the number of cells or in their DNA content, both of which were verified by two different methods. Therefore, an actual increased nuclear (autoradiographic) uptake of thymidine did take place in oestrogenized cells, associated with an increase of incorporation into DNA (a rise of radioactivity in the acid‐insoluble materials), but finally there was no greater total DNA increase in the whole treated population than in control cells.Then we examined the metabolism of tritiated thymidine in oestradiol‐treated FAM cells. We extracted the radioactive thymine nucleotides and characterized them chromatographically: the oestradiol caused an increase in the labelling of deoxythymine monophosphate (TMP). How these results are consistent with both unmodified cell count and whole DNA content is discussed.
The Sensitivity of G0‐State Haemopoietic Spleen Colony‐Forming Cells to A Stimulus For Proliferation
Authors: Lord B. I. 
Published: May 2008

AbstractHaemopoietic spleen colony‐forming units (CFU‐s) close to the axis (axial CFU‐s) of the long bones have a high probability of self‐renewal. They are pluripotent cells and are largely in a Go‐State. By contrast, CFU‐s close to the bone surface (marginal CFU‐s) have a lower probability of self‐renewal and are probably more mature, though still pluripotent. Most CFU‐s proliferation arises in this zone. As a consequence, marginal CFU‐s tend to have shorter Go histories than do axial CFU‐s. Femoral marrow was, therefore, divided into axial and marginal populations and the sensitivity of the CFU‐s to an endogenous CFU‐s‐specific proliferation‐stimulating factor was assessed and compared by the tritiated thymidine suicide technique. It was found that axial CFU‐s are considerably more resistant to stimulation than are marginal CFU‐s in that larger doses for longer periods of exposure are required to increase the proliferative activity of the cells. This behaviour is consistent with the suggestion that cells with a low division probability exist in deeper levels of the quiescent Go‐state. Although this hypothesis was developed from the behaviour of cells maintained in culture under sub‐optimal physiological conditions, this phenomenon appears, in vivo, to be a characteristic of the stem cell population of haemopoietic tissue; their high resistance to stimulation maintaining the axial CFU‐s in a quiescent state.
Kinetic and Physical Studies of Cell Death Induced By Chemotherapeutic Agents Or Hyperthermia
Authors: Dyson J. E. D. , Simmons Deena M. , Daniel Jill , McLaughlin J. M. , Quirke P. , Bird C. C. 
Published: May 2008

AbstractThe kinetics of three physical parameters: cell density, relative cytoplasmic viscosity and DNA stability to denaturation have been measured during the period preceding cell death induced by hyperthermia, methylprednisolone and a series of cancer chemotherapeutic agents. This series of measurements employed cultured human lymphoblastoid cells as an experimental system to establish the changes that can be observed in the early stages of cell death, prior to applying such measurements to tissue biopsies from solid human tumours. Cell death, induced by hyperthermia up to 43°C, methylprednisolone, vincristine, 5‐fluorouracil, BCNU and melphalan, showed essentially identical and reproducible changes corresponding to those which characterize programmed cell death (apoptosis). Such changes could also be observed following hyperthermia above 43°C, but reproducibility was poor and increasing damage to the cell membranes was evident. In cells treated with adriamycin or methotrexate, cell sub‐populations showing an increase in cell density were not detected. Measurements of DNA stability were readily performed by flow cytofluorometry thus allowing rapid quantitation of the fraction of cells in the early stages of cell death. Modified flow cytometric instrumentation would further allow measurement of cytoplastic viscosity as an additional parameter to indicate entry into programmed cell death. This suggests that these measurements could readily be applied to cell suspensions derived from tumour tissue biopsies for a more accurate assessment of tumour growth rate, and to allow monitoring of response to therapy in sequential tumour biopsies.
Rate of Loss of Tritiated Thymidine Label In Basal Cells In Mouse epithelial tissues
Authors: Bickenbach J. R. , McCutecheon J. , Mackenzie I. C. 
Published: May 2008

AbstractA subpopulation of epithelial cells which retains a tritiated thymidine label (termed label‐retaining cells, LRCs) has been previously demonstrated in skin and oral mucosae of mice and hamsters. to examine the rate of decrease in the number of LRCs and the changes in degree of labelling, young mice were labelled with tritiated thymidine and the rate at which label was diluted from basal keratinocytes assessed for up to 90 days. the number of LRCs in each tissue examined decreased from 15 to 90 days after labelling with the epidermal tissues maintaining a higher percentage of LRCs than the oral mucosae. Grain counts for LRCs in each tissue at each time period indicated that the number of silver grains overlying LRCs also decreased with time. the observed decrease in numbers of LRCs and the change in their degree of labelling with time suggest that such cells divide slowly, a property associated with stem cells.
Sleep Deprivation Alters the Cell Population Kinetics In the Jejunum of the Male Syrian Hamster (Mesocricetus auratus)
Authors: Jazwinska Elizabeth C. 
Published: May 2008

AbstractThe proliferative and functional units of the jejunum were studied every 3 hr during 24 hr in groups of control and sleep‐deprived hamsters. Peaks in kinetic parameters were evident during the sleep period in control hamsters; in the absence of sleep, peak values were significantly reduced. Sleep deprivation was associated with reduction of G2 to M flux and reduction of the circadian rhythm in mitotic index from 74% to 25%. the reduction in the number of cells passing through M was reflected by a drop in labelling index 9 hr later. These findings are consistent with the theory that sleep promotes restorative processes.
Rate and Time of Dna Synthesis of Human Leukaemic Blasts In Bone Marrow and Peripheral Blood
Authors: Ucci Giovanni , Riccardi Alberto , Dörmer Peter , Danova Marco 
Published: May 2008

Abstract. We have evaluated DNA synthesis rate (S rate) and time (Ts) and tritiated thymidine labelling index (LI) of peripheral blood (PB) and/or bone marrow (BM) leukaemic blasts (Bl) in nineteen cases of acute leukaemia (twelve non‐lymphoblastic, AnLL, and seven lymphoblastic, ALL), in one case of non‐Hodgkin's leukaemic lymphoma and in a case of plasma cell leukaemia.The LI of PB‐BI was significantly lower than that of BM‐Bl (range 0.1‐6.2% and 1.9‐19.5%, respectively; P < 0.01). the S rate was higher for PB‐Bl than for BM‐Bl (range 3.5‐11‐3 and 2.5‐9.5 mol × 10‐18/min; P < 0.02) and the Ts of PB‐Bl was shorter than that of BM‐Bl (range 7.6‐22.1 and 10.8‐34.7 hr, respectively; P < 0.02). In eight cases where S rates of both BM‐Bl and PB‐Bl were available, a linear correlation (r= 0.82; P < 0.01) was found between the two parameters. This suggests that the DNA synthetic rate is a property of the leukaemic cell line in individual patients and differs from case to case. It further indicates that the environmental influences on the DNA synthesis rate in BM or PB are always of the same order of magnitude. From the results of this study we speculate that the DNA synthesis rate of leukaemic blasts is slowed down in the BM by environmental factors such as cell density.
A Cytokinetic Study of Small‐Intestinal and Colonic Mucosa After Resection of 70% of the Small Intestine
Authors: Senior P. V. , Pritchett C. J. , Sunter J. P. , Appleton D. R. , Watson A. J. 
Published: May 2008

Abstract. Pulse‐labelling with tritiated thymidine and a fraction of labelled mitoses experiments have been performed in order to investigate the proliferative changes induced at various sites in the hyperplastic small‐intestinal mucosa of rats previously subjected to resection of 70% of the small intestine. Proliferative activity in the colon was also studied.In the distal ileum there is a significant reduction in cell cycle time (Tc) of cells at all levels within the crypt and the growth fraction falls. In the jejunum and proximal ileum the crypts contain an increased number of proliferating cells, but as the size of the maturation zone is also increased, there is no significant alteration in the relative number of proliferating cells per crypt. Nor does the distribution of proliferating cells in these crypts seem to alter. There is no general reduction in Tc at these sites, but there does appear to be a significant reduction in Tc on the part of the cells in the stem‐cell zone at the crypt base.In neither proximal nor distal colon was there any significant proliferative change apparent after small‐intestinal resection.
Cytokinetic studies on the switch from glucose to uridine metabolism, and vice versa, of Ehrlich ascites tumour cells in vitro
Authors: Löffler M. , Wenzel A. , Schneider F. 
Published: May 2008

Abstract. Glucose is normally required as the energy source and for the proliferation of neoplastic cells. For Ehrlich ascites tumour cells, kept under glucose‐free culture conditions, this requirement was alleviated by uridine, indicating that the supply of ribose is obligatory for sustaining growth capacity.In a 96‐hr culture experiment with mouse‐derived cells, the increase in cell number from cultures supplemented with 5 mM uridine was 50–70%, whilst lactate production was 5% that of controls. An increase in the number of multinucleate cells was observed from cell‐smears; DNA histograms indicated the presence of cells with a DNA content higher than 4c and an increased portion of cells in G2 phase. For precise determination of changes in cell cycle distribution on transfer of cells from glucose‐supplemented to glucose‐free conditions, the progression of phase‐accumulated cells (by centrifugal elutriation) was monitored by DNA distribution analysis; G2 cells continued the cycle at a rate comparable to controls but were delayed, in the following cycle, predominantly in S and G2 phases. This was also observed with G1 cells from a G1‐accumulated fraction in the first cycle.The addition of glucose to cells kept for some hours in glucose‐free, uridine‐supplemented medium resulted in an immediate increase in mitotic index (amplification by the colcemid method).The results are interpreted and support our concept that the delivery of compounds, necessary for normal growth, i.e. hexoses for glycoproteins and glycolipids, are limited as a consequence of the ‘metabolic channelling’ of pentose from uridine in Ehrlich ascites tumour cells. Therefore, the constantly lowered growth‐rate in uridine‐supplemented cells observed with long‐term culture experiments could reflect an adaption of growth‐cycle to these limitations.
Cell Cycle Redistribution of Cultured Cells After Treatment With Chemical Radiation Protectors
Authors: Sigdestad C. P. , Guilford W. , Perrin J. , Grdina D. J. 
Published: May 2008

ABSTRACTThe effect of two radioprotective agents (WR‐1065 and WR‐151326) was tested for their ability to modify cell cycle progression. Each protector was administered at a concentration of 4 mmol to exponentially growing cultures of V79 cells for periods of time up to 3 h. Under these conditions no cell toxicity was observed. At selected times up to and after removal of the protector, aliquots of cells were removed, counted and fixed in cold 70% ethanol. the cells were stained with DAPI in a 0.1% citrate solution and DNA histograms were obtained using a PARTEC PAS‐II flow cytometer. the coefficient of variation of the G1 peaks obtained for unperturbed cell samples routinely ranged from 1.5 to 2.5%. During exposure, both radioprotectors effectively perturbed cell cycle progression, as characterized by a build‐up of cells in S and G2 phases. After the protectors were removed, cells began to redistribute throughout the cell cycle. Twelve hours were required before cells exposed to WR‐1065 approached levels commensurable with controls. In contrast, cells treated with WR‐151236 required about 24 h to redistribute to control levels. These data demonstrate that different thiol‐containing radioprotective compounds can differentially affect the progression and redistribution of exposed cells.
A mathematical model of erythropoiesis in mice and rats Part 1: Structure of the model
Authors: Loeffler M. , Pantel K. , Wulff H. , Wichmann H. E. 
Published: May 2008

Abstract A mathematical model has been developed which describes the regulation of erythropoiesis in mice and rats. The main model assumptions are: (1) Regulation is mediated by erythropoietin (EPO). (2) The production of EPO depends exponentially on the tissue oxygen pressure (e.g. in the renal production sites). (3) There are sigmoidal dose‐response curves relating the EPO concentration in the plasma to the mitotic activity of CFU‐E and proliferative erythropoietic precursors. For maximum stimulation two to four additional mitoses may occur, while for an absent stimulus three to five mitoses may be omitted. (4) The normal precursor transit time of three to four days may be shortened by more than 50% during maximum stimulation. (5) The erythrocytes have a normal lifespan of 42–56 days, which may be reduced to 15–20 days under erythropoietic stimulation.Among these assumptions, the dose‐response relationships between EPO and the mitotic activity of CFU‐E and the proliferative erythropoietic precursors are the most important hypotheses of the model. This is the first of a series of three papers and gives a description of the mathematical formalism and the parameters used. In the subsequent papers computer simulations on erythropoietic stimulation and suppression are presented.
A mathematical model of erythropoiesis in mice and rats Part 2: Stimulated erythropoiesis
Authors: Wichmann H. E. , Loeffler M. , Pantel K. , Wulff H. 
Published: May 2008

Abstract A mathematical model of erythropoietic cell production and its regulation process has been proposed in a preceding paper. It is primarily based on the assumption that the number of cell divisions taking place in the CFU‐E and erythropoietic precursor stages is regulated depending on the oxygen supply of the tissue. Quantitative dose‐response relationships for in vivo erythropoiesis are suggested. Here, we demonstrate that this model adequately reproduces data obtained in situations of stimulated erythropoiesis in mice and rats. In detail, this implies a quantitative description of the following processes: (1) Changes in tissue oxygen tension (PtO2) following removal of red cells (bleeding, haemolytic anaemia) or increase in plasma volume (dilution anaemia) or decrease in atmospheric oxygen pressure (hypoxia). (2) PtO2 dependent erythropoietin (EPO) production. (3) Dose‐response of EPO on erythropoietic amplification (up to two to four additional mitoses). (4) The changes of the marrow transit time.Model simulations are compared with experimental data for changes of erythropoiesis during hypoxia, EPO‐injection, and different forms of anaemia. A satisfactory agreement suggests that the model adequately describes and correlates different direct and indirect ways to stimulate erythropoiesis. It quantifies the role and relative contribution of the haematocrit, haemoglobin concentration, atmospheric oxygen pressure, tissue oxygen pressure, and plasma volume as triggers in erythropoietic stimulation under various conditions. Furthermore, the model may allow to optimize the scheme of EPO‐administration and to find the maximum increase of erythropoiesis for a given amount of erythropoietin.
The cell kinetics of the epidermis and follicular epithelium of the rat: variations with age and body site
Authors: Morris G. M. , Hamlet R. , Hopewell J. W. 
Published: May 2008

AbstractThe skin from rats of differing age was used to quantify variations in the cell kinetics of the epidermis and the follicular epithelium of different body sites. Four parameters were assessed, namely the basal cell density (BCD), the labelling index (LI), the duration of DNA synthesis (ts) and the basal cell turnover time (tT). The BCDs of the epidermis of the dorsum and the upper surface of the foot were similar in rats of 7, 14 and 52 weeks of age, but there was an indication of a progressive decline with increasing age in the BCD of the epidermis of the ear and tail. There were no age‐related changes in the length oftsin any of the four body regions. The rate of cell proliferation, as indicated by the values of the LI andtT, was relatively rapid in the epidermis of the dorsum, foot and tail of rats aged 7 weeks (LI > 12%;tT< 80 h). In rats aged 14 weeks this rate of proliferation was maintaned in the epidermis of the dorsum. However, in the foot and tail the rate of cell proliferation was decreased (LI < 10%;tT> 85 h). A fall in the rate of proliferation of the epidermis of the dorsum was only seen in 52‐week‐old animals. In these animals the rates of proliferation in the foot and tail were similar to those at the age of 14 weeks. In the epidermis of the ear there was no appreciable change in the rate of cell proliferation with age.The values of the cell kinetic parameters varied in the different body sites. For example, in 52‐week‐old animals values fortTwere relatively short in the epidermis of the tail and foot and appreciably longer in the epidermis of the dorsum and ear.Considered overall, values for the cell kinetic parameters of the epidermis were comparable with those for the follicular epithelium. The only major differences between the epidermis and the follicular epithelium were in the upper surface of the foot at 7 weeks of age, and in the tail at 7 and 14 weeks of age, where the LI was higher and thetTshorter in the epidermis than in the follicular epithelium.The relevance of the observed age‐ and body‐site‐related variations in the cell kinetics of the epidermis are discussed in relation to previously described differential changes in the radiosensitivity of the skin in this strain of rat.