bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE IN VITRO DIFFERENTIATION OF DENSITY SUB‐POPULATIONS OF COLONY‐FORMING CELLS UNDER THE INFLUENCE OF DIFFERENT TYPES OF COLONY‐STIMULATING FACTOR
Authors: Byrne P. , Heit W. , Kubanek B. 
Published: May 2008

ABSTRACTThe in vitro proliferation and differentiation of myeloid progenitor cells (CFU‐c) in agar culture from CBA/Ca mouse bone marrow cells was studied. Density sub‐populations of marrow cells were obtained by equilibrium centrifugation in continuous albumin density gradients. The formation of colonies of granulocytes and/or macrophages was studied under the influence of three types of colony‐stimulating factor (CSF) from mouse lung conditioned medium CSFMLCM), post‐endotoxin mouse serum (CSFES) and from human urine (CSFHu). The effect of the sulphydryl reagent mercaptoethanol on colony development was also examined. The density distribution of CFU‐c was dependent on the type of CSF. Functional heterogeneity was found among CFU‐c with partial discrimination between progenitor cells forming pure granulocytic colonies and those forming pure macro‐phage colonies. Mercaptoethanol increased colony incidence but had no apparent effect on colony morphology or the density distribution of CFU‐c.
EFFECTS OF UTERINE DISTENSION AND OESTRADIOL ON CELL KINETICS IN THE ENDOMETRIAL EPITHELIUM OF OVARIECTOMIZED RATS
Authors: Leroy F. , Hoeck J. Van , Bogaert C. 
Published: May 2008

ABSTRACTCell kinetics in the uterine epithelium of ovariectomized rats were studied after uterine distension and/or an oestradiol injection, by cumulative 3H‐TdR labelling and percentage of labelled mitoses (PLM). With both methods it was found that distension shortens the total cell cycle at the expense of G1 more than does oestradiol. Both treatments act in a cumulative manner since the greatest reduction in Tc is observed after distension plus oestradiol. PLM curves showed that distension and/or oestradiol induce a 30% reduction in S phase duration. The evolution of percentages of labelled cells and colchicine‐blocked mitoses after these treatments confirms their additive effects and indicates that the mitogenic action of oestradiol is delayed compared to that of distension. It is suggested that these factors stimulate epithelial cell division in the uterus through partly different metabolic channels.
Dissecting the Hematopoietic Microenvironment
Authors: Wolf N. S. 
Published: May 2008

ABSTRACTAn analysis of the S1/S1d mouse for ferrokinetics and fate of peripheral red blood cells has shown the cause of its anemia to be dual in nature. While the S1/S1d produces red cells at a slightly greater rate than its normal littermate, its bone marrow and spleen appear to be operating near their maximal capacity and will reduce their output if anemic stress is partly relieved. the cause of the moderately high level of erythropoiesis in the S1/S1d is a mean daily loss of 2.5–3.0% of its total blood volume via the intestinal tract.
Dissecting the Hematopoietic Microenvironment
Authors: Wolf N. S. 
Published: May 2008

ABSTRACTExperiments were carried out with the intent of defining the nature of the microenvironmental defect which severely limits erythropoiesis in the spleen of the S1/S1d mouse. Chimeric spleens, half S1/S1d and half congenic +/+, supported erythropoiesis in the +/+ region but not in the S1/S1d region, regardless of which genotype was the irradiated, marrow‐injected host animal. Implants of normal marrow stroma within the spleens of irradiated S1/S1d mice also supported normal proportions of erythrocytic and granulocytic hematopoiesis. Implants of normal spleen stroma, particularly the capsular portion, into unirradiated S1/S1d mice stimulated erythropoiesis originating from S1/S1d stem cells within and in the immediate vicinity of the implant. the evidence suggests a short range, stromal erythropoietic stimulatory factor which is lacking in the S1/S1d.
Analysis of the Progression of Meiosis In Dispersed Rat Testicular Cells By Flow Cytofluorometry
Authors: LIBBUS B. L. , SCHUETZ A. W. 
Published: May 2008

ABSTRACTInitiation and progression of meiosis was followed in dispersed rat testicular cells by flow cytofluorometry and cytology. the DNA content of dissociated testicular cells of rats 6–30 days old, killed at daily intervals, was analysed by flow cytofluorometry using propidium iodide as a DNA‐specific and quantitative fluorochrome. Testicular cells of a 6‐day‐old rat showed one peak of fluorescence. A second peak, at twice the modal channel number, appeared in testicular cells of 9‐day‐old animals. the number of cells under this peak increased progressively with age. A third peak, at half the channel number of the original one, appeared at 20 days and accounted for an increasing proportion of cells in testes taken from older rats. Cytological examination of the testicular tissue used for flow cytofluorometric analysis showed that preleptotene spermatocytes first appeared at 8 days after birth. Spermatids were first observed cytologically at 20 days after birth. the close temporal appearance of the fluorescence peaks with that of spermatocytes and spermatids, and the close association of the frequency of diploid and tetraploid cells as derived by flow cytofluorometry and cytology, indicated that the fluorescence peaks correspond—in order of increasing fluorescence—to spermatids, spermatogonia and somatic cells, and to spermatocytes. This conclusion was re‐examined by analysing the ploidy levels of testicular cells of hypophysectomized or estradiol‐treated animals by flow cytofluorometry. There was a loss of the haploid and tetraploid peaks subsequent to hypophysectomy. Estradiol dipropionate‐treated rats, given weekly injections starting at 7 days of age, showed no appearance of the haploid peak and the regression of the tetraploid peak after an initial and transitory appearance.These results indicate that changes in ploidy levels that accompany the progression of meiosis in the testis were reflected in the sequential appearance of three fluorescence peaks as detected by flow cytofluorometry. the close correlation
Stimulating Factors and Cell Recruitment In Murine Bone Marrow Stem Cells and Emt6 Tumours
Authors: Frindel E. , Guigon M. , Dumenil D. , Fache M. P. 
Published: May 2008

ABSTRACTThe role of a stimulating factor in cell recruitment and the kinetics of its secretion were investigated by in vivo and in vitro techniques. the association of these two methods made it possible to demonstrate that a non‐cycling population liberates a factor which in turn stimulates quiescent bone marrow stem cells into DNA synthesis. Moreover, it seems that undamaged cells are capable of secreting this factor. A stimulating factor responsible for cell recruitment was also demonstrated in an experimental EMT6 tumour and the kinetics of its secretion reported.
Nucleic Acid Profile of the Emt6 Cell Cycle In Vitro
Authors: Watson J. V. , Chambers S. H. 
Published: May 2008

ABSTRACTSimultaneous RNA and DNA estimations were carried out during the cell cycle of EMT6/M/CC cells growing in vitro following synchronization by mitotic selection. the determinations were performed with a flow cytofluorimeter on individual cells stained with acridine orange. It was found that the RNA content increased during G1 then remained virtually constant between early and mid S phase, but a second increase occurred during late S. the rate of uptake of tritiated uridine paralleled these changes in RNA levels, and it was also found that the rate of uptake in metaphase and anaphase was virtually zero, but a rapid increase occurred in telophase. the increase in DNA during S was approximately linear, and the intermitotic phase and cycle durations were very similar to previously reported results.
Quantitative Description of Cell Cycle Kinetics Under Chemotherapy Utilizing Flow Cytometry
Authors: Kim M. , Wheeler B. , Perry S. 
Published: May 2008

ABSTRACTA discrete time cell cycle kinetics model is developed to account for the effects of cytotoxic chemotherapy, particularly including the existence of cells destined to die. A model structure is determined from related experiments, leaving key parameter values undetermined. These values are found by determining the best least squares fit of the predicted to the observed DNA distribution data at a series of time intervals. the numerical methods include separable least squares, linear inequality constrained least squares and the Gauss‐Newton method. This approach is applied to an experiment in which the Ehrlich ascites tumour was given a single dose of bleomycin. the results include several different parameters, including the age response function and a time series of cell age and DNA distributions, which can be used as a basis for further treatment.
Contribution to the Understanding of the Mechanism of Cytokinesis In Plant Cells: the Action of Deoxyguanosine On the Kinetics of A Root Meristem Cell Population
Authors: Lasselain M.‐J. , Pareyre C. , Deysson G. 
Published: May 2008

ABSTRACTThe kinetics of binucleate cells, formed by the action of deoxyguanosine, are studied using three methods: in a population synchronized with hydroxyurea, by autoradiography after pulse‐labelling, and in a sample of a cell population morphologically located at the M‐G1, limit. Deoxyguanosine induces a slowing down in S and G2, independent of the inhibition of cytokinesis. It is only when it takes effect during the G2, stage that deoxyguanosine brings about the formation of binucleate cells.
Dose‐Dependent Cytokinetic Changes Following 1‐β‐D‐Arabinofuranosylcytosine and Hydroxyurea In L1210 and S‐180 In Vivo
Authors: Straus M. J. , Moran Ruth E. 
Published: May 2008

ABSTRACTDNA synthesis inhibition and recovery in L1210 and S‐180 ascites tumors following 1‐β‐D‐arabinofuranosylcytosine (Ara‐C) and hydroxyurea (HU) were measured autoradiographically as a basis for optimizing drug schedules. Tumor bearing mice, 106 cells day O, were treated on day 4 with 20, 200 or 2000 mg/kg Ara‐C or 50, 300 or 1800 mg/kg HU. At various intervals following drug, [3H]thymidine was administered i.p. and mice were killed 1 hr later. Tumor cells were analyzed for labeling index (LI) and grain count (GC) to determine the percentage of cells in S phase and the distribution of DNA synthesis rates among the labeled cells, respectively. Following each dose of HU, DNA synthesis was inhibited completely. Recovery of LI was rapid and approached control values by 6 hr. Following each dose of Ara‐C, DNA synthesis was inhibited completely for at least 6 hr. Recovery of LI was first noted 6 hr following 20 mg/kg Ara‐C and 9 hr following 200 mg/kg. Following both doses the LI reached 100% of the control value by 26 hr. GC analysis indicated that following Ara‐C treatment, DNA synthesis was reinitiated first with cells with low GC from 6 to 12 hr followed by cells with increasing GC from 12 to 20 hr. the labeling intensity reached control values by 20 hr and an ‘overshoot’ occurred by 26 hr. These data suggest that the recovery of DNA synthesis rate is a gradual process. Survival data for mice receiving two doses of Ara‐C indicated that the optimal interval for retreatment following the lower dose of Ara‐C occurred by 6 hr as compared to 12–16 hr for the higher dose. These times coincided in both instances with recovery of LI to 33–50% of control values. Early recovery of LI may be the best method currently available for estimating the optimal time for retreatment with an S phase specific drug.
Specific Inhibition of Cell Proliferation In the Mouse Intestine By an Aqueous Extract of Rabbit Colon
Authors: Sassier P. , Bergeron M. 
Published: May 2008

ABSTRACTAqueous extracts from rabbit colon, kidney, testis and small intestinal mucosa were prepared by homogenization and centrifugation at 105,000 g. After precipitation with ammonium sulphate. the 0–50 fraction (F1) and the supernatant (F2) were collected, dialysed against a phosphate buffer and tested on mice in vivo.1 hr after a single injection of F1 (15 mg content) from colon, the uptake of tritiated thymidine was decreased in jejunal and colonic DNA in mice. This effect, maximal after 3 hr and totally reversible after 7 hr, was found in neither the kidney nor the testis. the F1 fractions of non‐digestive organs (kidney, testis) were also found to exert a significant inhibition on thymidine incorporation into intestinal DNA in vivo. F1 fractions of intestinal contents, prepared under the same conditions, exerted no significant effects on DNA synthesis in mouse intestine. Conversely, the colon F2 fraction did not inhibit the synthesis of jejunal and colonic DNA in vivo. A slowing of cellular migration was also noticed in the jejunum and colon of mice injected with colon or small intestine F1, as ascertained radioautographically by determining the position of the leading edge of the labelled cells in jejunal or colonic F1‐injected mice.Our results suggest that the F1 fraction of the aqueous extract of rabbit colon contains one or more substances, which may act either on intestinal DNA synthesis or on the G1‐S transition of the cellular cycle in the mouse intestine. This reversible and tissue‐specific intestinal action appears to inhibit cell proliferation and presents several of the characteristics defining a chalone, as does the action of small intestinal F1 previously reported (Sassier & Bergeron, 1977). However, because of a relative lack of origin specificity of this effect, the physiological significance of our data remains to be ascertained.
The Growth of the Emt6 Tumour In the Lungs of Balb C Mice Following Intravenous Inoculation of Tumour Cells From Culture
Authors: TWENTYMAN P. R. 
Published: May 2008

ABSTRACTThe growth of the EMT6 tumour in the lungs of Balb C mice has been studied following intravenous inoculation of different numbers of tumour cells taken from culture. At various times after injection of cells into mice, cell suspensions have been prepared from pairs of lungs and the number of in vitro colony forming cells assayed by plating into petri dishes. Following intravenous injection of 105 cells, the time required for doubling of the number of clonogenic tumour cells appearing in the cell suspension is around 17 hr until such time that the total tumour cell population per set of lungs reaches 108 cells (at 10–12 days). This doubling time has to be corrected for changes in ability to extract cells from the lungs into the cell suspension at various times and also for possible changes in plating efficiency in vitro. When these correction factors are applied, the most likely value for the doubling time of clonogenic tumour cells in the lungs is in the range 20–24 hr. This is a similar figure to that previously deduced for the EMT6 flank tumour during its microscopic period of growth.After reaching a total size of 108 tumour cells, the time for doubling of the number of clonogenic tumour cells in the lung increases. During the later stages of tumour growth a good correlation is seen between total lung tumour weight and the number of clonogenic cells present.For the final 3–4 days of the initial period of rapid tumour growth, it is possible to carry out a haemocytometer count of tumour cells in the lung suspension and hence surviving fraction experiments may be carried out after various forms of treatment. In this way the response to treatment of microscopic tumour foci may be determined.
Characteristic Species Dependent Growth Patterns of Mammalian Neoplasms
Authors: Brunton G. F. , Wheldon T. E. 
Published: May 2008

ABSTRACTEvidence is presented, arising from an analysis of published data on tumour growth in three species of laboratory animals and in human multiple myeloma supporting a species specific relation between two supposedly independent parameters in the Gompertz equations frequently used to quantify tumour growth curves. This evidence supports the conjecture of Norton et al. (1976), based on their observations of the growth kinetics of a murine melanoma and a rat mammary carcinoma, that such a relation may be a general feature of tumour growth. Published data on the growth of xenografts of human colorectal tumours in immune‐deprived mice suggests that the observed growth relation reflects the ability of a particular species to support a tumour of a certain maximum size. the existence of this relation greatly simplifies the task of predicting complete patterns of undisturbed neoplastic growth in these species.
ANALYSIS OF THE GROWTH KINETICS OF A HUMAN LYMPHOMA CELL LINE
Authors: Drewinko B. , Bobo B. , Roper P. R. , Malahy M. A. , Barlogie B. , Jansson B. 
Published: May 2008

ABSTRACTThe growth kinetics of an established human lymphoma cell line were analyzed by a variety of techniques utilizing various cell inocula (5 x 104 ‐ 5 x 105 cells) dispensed into 60 mm diameter dishes. Techniques included pulse‐labeled mitosis (PLM), continuous labeling with 3H‐TdR, time‐lapse photography (TLP), cell counts by electronic particle counter, and DNA histography obtained by pulse cytophotometry (PCP). There were no significant differences among values determined for any kinetic parameters as a function of cell concentration. the average doubling time of exponentially growing cells, regardless of cell inoculum, was 44.1 hr. the generation time determined by PLM was 31.1 hr with a SD of 4.7 hr. Transit times for each stage were: TG1= 10.6 hr, Ts= 9.9 hr, TG2= 9.9 hr, and Tm= 0.7 hr. Repeated experiments using continuous labeling with 3H‐TdR demonstrated a TG2 of 6.3 hr. the longer value determined by PLM is possibly due to the technical manipulations of this procedure which may delay pulse‐labeled cells from resuming cell cycle transit. Hence, values for cell cycle stages were recalculated to give TG1= 14.1 hr, Ts= 9.9 hr, TG2 = 6.3 hr, and Tm= 0.7 hr. These results were used to compute the size of each cell cycle stage compartment pool and corresponded very closely to values defined directly by PCP. TLP analysis considered only cells that produced colonies of at least thirty‐two cells. Generation times ranged from 8 to 89 hr and showed a positive skewness. the average value measured for 330 divisions was 34.5 hr with a SD of 13.2 hr. Thus, the variance predicted by curve fitting of the PLM data did not correlate with that defined by time‐lapse photography nor did it encompass the range in generation times observed directly by TLP. There was a positive correlation between sister‐sister cell generation times (+0.66) but no relation was noted for mother‐daughter values.
TUMOUR CELL PROLIFERATION IN RELATION TO THE VASCULATURE
Authors: Hirst D. G. , Denekamp J. 
Published: May 2008

ABSTRACTThe proliferation pattern of a transplantable mouse mammary carcinoma has been studied in relation to its macroscopic and microscopic structure. No significant differences were seen in the labelling or mitotic indices or in the percentage labelled mitoses curves for the peripheral 2‐0 mm rim or for the central tumour core.When these parameters were scored for cells classified according to their position in relation to capillaries or to necrotic regions, marked differences were observed in all the parameters. Higher labelling and mitotic indices and higher grain counts were seen adjacent to the capillaries. These appear to result from a shorter cell cycle duration and a higher growth fraction. The variation in cell cycle is mainly due to a change in the duration of G1.
FLOW CYTOMETRIC CELL CYCLE ANALYSIS USING THE QUENCHING OF 33258 HOECHST FLUORESCENCE BY BROMODEOXYURIDINE INCORPORATION
Authors: Bohmer R. ‐M. 
Published: May 2008

ABSTRACTCultures of L cells were grown in medium containing 2.0 mg/l bromodeoxyuridine (BUdR) and stained with the fluorescent dye 33258 Hoechst for flow cytometric analysis. During exposure to BUdR, the cells replace thymidine by BUdR in the newly synthesized DNA. The new DNA is not stainable with 33258 Hoechst, which is highly specific for thymidine. The temporal development of the fluorescence distributions after addition of BUdR to the growth medium has been investigated in the flow cytometer, and the data were used to calculate the mean durations of the phases G1, S and G2+ M in exponentially growing cultures as well as the cycle transit times in synchronized cultures. The percentage of non‐cycling cells was determined in each experiment.
THE DISCRETE–TIME KINETIC MODEL ANALYSIS OF DNA CONTENT DISTRIBUTIONS IN EXPERIMENTAL TUMOUR CELLS
Authors: Woo K. B. 
Published: May 2008

ABSTRACTA method was developed to analyse and characterize FMF measurements of DNA content distribution, utilizing the discrete time kinetic (DTK) model for cell kinetics analysis. The DTK model determines the time sequence of the cell age distribution during the proliferation of a tumor cell population and simulates the distribution pattern of the DNA content of cells in each age compartment of the cell cycle. The cells in one age compartment are distributed and spread into several compartments of the DNA content distribution to allow for different rates of DNA synthesis and instrument dispersion effects. It is assumed that the DNA content of cells in each age compartment has a Gaussian distribution. Thus, for a given cell age distribution the DNA content distribution depends on two parameters of the cells in each age compartment: the average DNA content and its coefficient of variation. As the DTK model generates the best fit DNA content distribution to the FMF measurement data, it enables one to estimate specific values of these two parameters in each stage of the cell cycle and to determine the fraction of cells in each cycle phase. The method was utilized to fit FMF measurements of DNA content distributions and to analyse their relationship to the cell kinetic parameters, namely cell loss rate, cell cycle times and growth fraction of exponentially growing Chinese hamster ovary cells in vitro and, also, with a wide range of coefficients of variation, of the L1210 ascites tumour during the growth period.
AN EXAMINATION OF SOME BASIC ASSUMPTIONS OF DNA DISTRIBUTION ANALYSIS USING BIOLOGICAL DATA
Authors: Brunsting A. , Collins J. M. , Kane F. R. , Bagwell C. B. 
Published: May 2008

ABSTRACTAn examination is made of how the observed DNA distributions spread from their original biological distributions. Using distributions from testicular and hepatic tissue we find that the current assumptions for DNA distribution analysis need re‐examination and suggest how this might be done.
LABELLING INDEX OF HUMAN SQUAMOUS CELL CARCINOMAS
Authors: Chavaudra N. , Richard J. M. , Malaise E. P. 
Published: May 2008

ABSTRACT In vivo and in vitro labelling has been compared in sixteen human solid squamous cell carcinomas (ENT). The median in vivo/in vitro LI ratio was 1·2, but for two‐thirds of the patients it was only 1·1, suggesting a slight LI underestimation in vitro. Two factors can possibly explain the divergences: heterogeneity from one biopsy to another in the same tumour, and lower mean grain count in the deep cell layers of the in vitro labelled tumour samples. Therefore, the fact we did not find a good agreement between in vivo and in vitro data for one‐third of the tumours points out that one must be cautious in considering in vitro LI as a valid result for a given patient. However, even if the in vitro LI leads to a certain underestimate, it can provide useful data.