bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Erythropoietic Stimulation of the Chamber Host On the Growth of Haemopoietic Colonies In Plasma Clot Diffusion Chambers (PCDC)
Authors: Pojda Z. , Wiktor‐Jedrzejczak W. 
Published: May 2008

AbstractMurine marrow cells were cultured in Millipore diffusion chambers implanted into the peritoneal cavity of variously conditioned murine hosts. Preirradiation (350 cGy), bleeding (0.5 ml) and phenylhydrazine injection (75 mg/kg i.v.) when performed together on the chamber host, induced better growth of erythropoietic and granulopoietic colonies inside the PCDCs than either of these manoeuvres alone. Small erythrocytic colonies (CFU‐E derived) and small granulocytic colonies were observed at day 3 of marrow culture. Erythropoietic bursts and large granulocytic colonies were observed at day 8 of chamber culture. Colonies of macrophage‐like cells, fibroblast‐like cells, mixed erythro‐granulopoietic colonies and megakaryoblasts were observed less regularly in chambers incubated in these conditions. the study provides a standardized, relatively reproducible PCDC culture system for studies of both erythro‐ and granulopoiesis, and does not require a hypoxic chamber.
Use of Growth‐Attachment Correlation Plots to Analyse Human Melanoma Cell Dependency On 2‐Oxocarboxylates and Serum
Authors: Kay G. F. , Ellem K. A. O. 
Published: May 2008

AbstractModulation of the population‐dependent growth of the human melanoma line MM96 by serum and a series of 2‐oxocarboxylates was analysed by a method offering several useful features. Initial cell attachment was measured by the use of cells prelabelled with [14C] thymidine (C) while the size of the replicating cell population on any particular day was monitored by [3H] thymidine (H) incorporation for that particular 24 hr. the 3H incorporation was normalized for the initial cell attachment as the 3H/14C ratio (H/C), which was found to be little affected by artifacts of precursor equilibration. the method allows large numbers of replicate samples so that quantitation of dose‐response relationships is simple and statistically robust, and simultaneous monitoring of cell attachment and growth within the same sample is routine.Not only cell growth, but also attachment to the culture vessel surface was found to be increased by higher seeded population densities, by increasing serum concentration and by pyruvate supplementation. Further investigation of the pyruvate effect showed that all nine of the soluble 2‐oxocarboxylates tested were effective for both parameters, with little difference between them which was attributable to molecular structure.Quantitative studies of the potentiation of growth and attachment by increasing cell density or a range of concentrations of 2‐oxocarboxylates led to the finding that increments in the growth parameter (H/C) were directly proportional to increments in attachment (C). Such a relationship would be unexpected in ordinary logarithmically‐growing cultures. the observation is consistent with the hypothesis that increases in initial cell attachment, whether induced by 2 oxocarboxylates or higher inoculation densities, lead to conditioning of the medium by cell factors which stimulate growth and are produced in amounts proportional to the attached cell numbers. Pyruvate, when present with higher serum concentrations, stimulated growth above the levels accounted for by concomitant increases in cell attachment. Serum also appears to have other potentiating factors in addition to those attributable to its content of 2‐oxocarboxylates. Differences in the response to 2‐oxocarboxylates of human melanoma cells and human diploid fibroblasts were noted, and suggest that the present observations may be due to unique properties of the melanoma cell.
Digestive Tract Cell Proliferation and Food Consumption Patterns of Ha/Icr Mice
Authors: Burholt D. R. , Etzel S. L. , Schenken L. L. , Kovacs C. J. 
Published: May 2008

AbstractThe relationship between the daily pattern of food consumption and the proliferation rate of the qesophagus, stomach, forestomach, small intestine and colon of Ha/ICR mice was examined. Proliferative activity was determined by [3H]TdR incorporation on a wet weight tissue basis, along with selective counting of labelled nuclei. Under conditions of ad libitum feeding with a 12 hr light cycle (lights on at 0600) mice eat most of their food during the dark period. A distinct circadian rhythm was observed in the oesophagus, stomach, forestomach and colon with the peak of [3H]TdR incorporation between 0400 and 0600 and the nadir between 1600 and 1800. Although a circadian fluctuation was observed in the small intestine, its amplitude was much less than in other areas. This rhythmic change in proliferation rate could be phase shifted by allowing the mice to feed only between 0800 and 1600 for 14 days. Under these conditions the peak in proliferative activity occurred between 1800 and 2000. Fasting reduced the daily level of proliferative activity in all of the digestive tract sites studied, and for all areas except the oesophagus greatly reduced or eliminated the circadian fluctuation. the forestomach and colon were the most influenced by fasting with 24 hr [3H]TdR incorporation reduced to 30–40% of the control value. Refeeding following a 48 hr fast produced a rapid increase in proliferative activity peaking at levels well above the control value at 16 hr after the onset of refeeding. the major exception to this was the small intestine which slowly returned to the control value during the first 24 hr. Partial refeeding produced a diminished refeeding response. Once the normal pattern of food consumption was re‐established following refeeding the normal proliferative fluctuations were again observed.
Separation By Velocity Sedimentation of Human Haemopoietic Precursors Forming Colonies in vivo and in vitro Cultures
Authors: Niskanen E. , Wells J. R. , Golde D. W. , Cline M. J. 
Published: May 2008

AbstractCells which give rise to granulocyte‐macrophage colonies under the influence of peripheral blood white cells (CFU‐c (WBC)) and Mo T cell conditioned medium (CFU‐c (Mo)) sedimented at a faster rate than the cells which form mixed erythroid‐granulocytic colonies in methylcellulose in vitro (CFU‐mix) and granulocytic (CFU‐dg) and megakaryocytic (CFU‐dm) colonies in diffusion chambers in mice. Despite identical peak sedimentation rate for the two CFU‐c populations, sedimentation profiles suggest that they are heterogeneous with respect to size. A proportion of CFU‐c (Mo) may be identical with CFU‐dg and CFU‐mix. Sedimentation profiles for cells which give rise to mixed colonies in vitro (CFU‐mix) and to granulocytic colonies in diffusion chambers in cyclophosphamide pretreated mice (CFU‐dg (CY)) and in Mo conditioned medium treated mice (CFU‐dg (Mo)) were similar. On the average CFU‐dm sedimented somewhat slower than CFU‐dg. These and other observations suggesting a close relationship between CFU‐dg and multipotential haemopoietic precursors are discussed.
Pig Epidermis: A Cell Kinetic Study
Authors: Morris G. M. , Hopewell J. W. 
Published: May 2008

AbstractThe basal cell density (BCD), labelling index (LI), duration of DNA synthesis (Ts) and cell cycle time (Tc) have been calculated for the epidermis of pigs in the age range 4–27 months. the BCD declined progressively from 143.4 ± 6.5 cells/mm at 4 months to 128.8 ± 8.3 cells/mm at 15 months, whereafter the values showed little change. There was a small decrease in LI with increasing age, from 7.9 ± 1.5% at 4 months to 5.9 ± 1.0% at 27 months. However, the change to housing animals outdoors as compared with indoors had a greater effect on the LI (∼10%). Severe weathering in the skin of animals housed outdoors resulted in a very high LI (∼20%). Neither Ts or Tc varied significantly with age. Ts was within the range 8.8–9.2 hr and Tc 127–161 hr. In animals housed outdoors Tc was reduced relative to animals housed indoors. the BCD and Ts were not affected by housing conditions. the kinetic parameters investigated in the pig were similar to those reported for man.
Analysis of Cell Flow and Cell Loss Following X‐Irradiation Using Sequential Investigation of the Total Number of Cells In the Various Parts of the Cell Cycle
Authors: Skog S. , Tribukait B. 
Published: May 2008

AbstractThe cell flow and cell loss of an in vivo growing Ehrlich ascites tumour were calculated by sequential estimation of changes in the total number of cells in the cell cycle compartments. Normal growth was compared with the grossly disturbed cell flow evident after a 5 Gy X‐irradiation.The doubling time of normal, exponentially growing cells was 24 hr. the generation time was 21 hr based on double‐isotope labelling studies and the potential doubling time was 21 hr. Thus, the growth fraction was 1.0 and the cell loss rate about 0.5%/hr. Following irradiation, a transiently increased relative outflow rate from all cell cycle compartments was found at about 3 and 40 hr, and from S phase at 24 hr after irradiation. Minimum flow rates from all compartments were found up to 20 hr. Cell loss as calculated from the cell flow was compared with non‐viable cells determined by Percoll density separation. Increase in cell loss as well as non‐viable cells was observed at 24 hr after irradiation at the time of release of the irradiation‐induced G2 blockage. Up to 50 hr, about 70% of the initial total number of cells were lost. the experiments show the applicability and limitations of cell flow and cell loss calculations by sequential analysis of the total number of cells in the various parts of the cell cycle.
Dna Synthesis Rate Changes During the S Phase In Mouse Epidermis
Authors: Clausen O. P. F. , Kirkhus B. , Elgjo K. , Pedersen S. , Bolund L. 
Published: May 2008

AbstractThe in vivo DNA synthesis rate throughout the S phase of mouse epidermal cells was investigated. Epidermal basal cells were isolated at various times of the day from normal animals injected with [3H]TdR 30 min before sacrifice, and from pulse‐labelled animals with regenerating and growth‐inhibited epidermis. the cells were analysed by DNA flow cytometry combined with cell sorting. Cells from successive fractions of the S phase were sorted on glass slides and subjected to quantitative [3H]TdR autoradiography.The results confirmed the presence of unlabelled (slowly replicating) cells in the S phase, the proportion of which was circadian stage‐dependent with minimum values at midnight and in the early morning. the DNA synthesis rate throughout the S phase showed a general trend with high values in the mid‐fractions, a pattern which was similar in normal and in growth perturbed epidermis. In the early morning the DNA synthesis rate pattern was bimodal with maxima both in the first and second half of the S phase, with a corresponding trough in mid‐S. At this time of day the cell progression rate through S is at its maximum, indicating a relationship between the overall DNA synthesis rate and the rate distribution pattern through S.
Mesenteric Lymphoblast Localization Throughout the Murine Small Intestine: Temporal Analysis Relating Intestinal Length and Lymphoblast Division
Authors: McDermott M. R. , Horsley Beverley A. , Warner Alison A. , Bienenstock J. 
Published: May 2008

Abstract. Mesenteric lymphoblasts (MLN) have a predilection to selectively localize in the lamina propria and epithelium of the small intestine. Using an adoptive transfer method, we examined the localization kinetics of these blasts in the intestinal wall with respect to their distribution from duodenum to terminal ileum and also assessed their mitotic activity by autoradiographic techniques. 3H‐thymidine‐labelled MLN cells were found throughout the small intestine by 6 hr post‐transfer and reached a maximum frequency in this organ by 24 hr post‐transfer.Donor blasts were most frequent in the duodenum and terminal ileum regions of the gut. Subsequently, the frequency of labelled cells throughout the intestinal wall declined to near zero. the apparent accumulation of MLN blasts in the gut was not related to either a temporary retention and departure from the pulmonary vasculature or to mitotic division of labelled cells in the gut wall. A model describing the relationship between MLN blast localization kinetics in various segments of the intestine was formulated.
Stathmokinetic Analysis of Human Epidermal Cells in vitro
Authors: Kimmel Marek , Darzynkiewicz Zbigniew , Staiano‐Coico Lisa 
Published: May 2008

AbstractProliferation kinetics of cultured human epidermal cells is characterized in quantitative terms. Three distinct subpopulations of keratinocytes, two of which are cycling have been discriminated by two parameter DNA/RNA flow cytometry. Based on mathematical modelling, the cell cycle parameters of the cycling subpopulations have been assessed from stathmokinetic data collected at different time points after initiation of cultures (7–15 days). the first subpopulation is composed of low‐RNA cells which resemble basal keratinocytes of epidermis and which show some characteristics of stem cells; these cells have a mean generation time of approximately 100 hr. the second subpopulation consists of high‐RNA cells, resembling stratum spinosum cells of epidermis, which have an average generation time of approximately 40 hr. the third subpopulation consists of non‐cycling cells with Go/G1 DNA content, with cytochemical features similar to those of cells in granular layer of epidermis.The results based on modelling can reproduce with acceptable accuracy the actual growth curve of the cultured cell population. Analysis of kinetics and differentiation of human keratinocytes is of interest in view of the recent application of cultured epidermal cell sheets for transplantation onto burn wounds. the results of this study also reveal the existence of regulatory mechanisms associated with proliferation and differentiation in the cultured epidermal cell population.
Cell Kinetic Studies of the Effect of A Combined Therapy With 1‐βd‐Arabinofuranosylcytosine (Ara‐C) and X‐Irradiation On the L1210 Ascites Tumour
Authors: Fietkau R. , Maurer‐Schultze B. 
Published: May 2008

Abstract. We studied the effect of combined therapy with X‐ray and 1‐β‐D‐arabinofuranosylcytosine (Ara‐C); firstly the effect of whole‐body X‐irradiation alone on the proliferation of the L1210 ascites tumour of the mouse was studied by autoradiographic and cytofluorometric (FCM) methods. the effect of X‐irradiation with 4 Gy was mainly a cytostatic one leading to an altered distribution of the cells throughout the cycle due to radiation induced mitotic delay. the cytocidal effect is negligible.As is known from previous studies (Fietkau, Friede & Maurer‐Schultze, 1984) the effect of 200 mg/kg Ara‐C consists of an inhibition of DNA synthesis and of killing a considerable portion of the L 1210 cells, predominantly of S phase cells.With respect to the importance for potential therapeutic regimens, the influence of the sequence and the time interval between the two therapeutic steps on the survival of tumour‐bearing mice was studied. Most combination therapies significantly increase the survival of tumour‐bearing mice compared to the single therapeutic steps; however, no significant differences between the various combined therapies were found. Whole‐body X‐irradiation with 4 Gy followed by the application of 200 mg/kg Ara‐C 10 hr later resulted in the greatest increase of the mean survival time of tumour‐bearing animals, from 13.2 to 17.4 days. It was shown that apart from the cytocidal effect on S‐phase cells, Ara‐C also kills cells sublethally damaged by a preceding X‐irradiation.
Use of Bromodeoxyuridine For Cell Kinetic Studies In Intact Animals
Authors: Wynford‐Thomas D. , Williams E. D. 
Published: May 2008

Abstract. A method is described for the use of BUdR for tracing cell proliferation patterns in the intestinal mucosa of intact mice.The method has several distinct advantages over existing methods.Bromodeoxyuridine (BUdR) is a well‐established alternative to tritiated thymidine ([3H]TdR) as a tracer for studying DNA replication. However, its use in cytological as opposed to biochemical studies has been largely confined to examination of metaphase spreads, particularly analysis of sister chromatid exchange (Block, 1982). For this, BUdR incorporation into DNA has been demonstrated using the fluorescent dye Hoechst 33258, together with fluorescence microscopy (Latt, 1973), or Giemsa staining (Perry & Wolf, 1974). Recently, introduction of a monoclonal antibody which recognizes BUdR in single‐stranded DNA (Gratzner, 1982) has enabled BUdR to be used for studying cell cycle kinetics in a manner exactly analogous to the use of [3H]TdR. This has been reported for whole cells in suspension and in monolayer (Dolbeare et al., 1983; Dean et al., 1984; Raza et al., 1984). BUdR included in tissue culture medium is taken up and incorporated into newly synthesized DNA via the same pyrimidine salvage pathway as [3H]TdR (thymidine kinase). A concentration of as little as 10 μm—well below cytotoxic levels (Cerni, 1984)—is sufficient to give readily detectable labelling by immunocytochemistry with a pulse of less than 15 min. the validity of BUdR labelling for cell kinetic studies has been well established in comparisons with other methods by Dolbeare et al. (1983), Dean et al. (1984), and Raza et al. (1984).We describe here the use of BUdR together with an immunocytochemical detection system applied to sections of wax‐embedded tissues, which provides a convenient method of cell cycle analysis in intact animals.
Rate of Incorporation of R3hlthymidine In Various Tissues of the Mouse A basis for the evaluation of genotoxic effects of chemicals
Authors: Hellman Björn , Ullberg Sven 
Published: May 2008

Abstract. [3H]Thymidine has been extensively used as a selective precursor to DNA in studies on the kinetics of cell proliferation. We have become interested in measuring early inhibition of the DNA synthesis in various organs of intact animals for detecting genotoxic properties of chemicals. Such experiments should, for convenience and to achieve a large capacity, be performed in the simplest way possible.The present paper deals with some practical aspects on the use of [3H]thymidine in vivo. [6‐3H]Thymidine was injected intraperitoneally in mice and the uptake of radioactivity was evaluated by using whole‐body autoradiography and liquid scintillation spectrometry. Autoradiograms of sections washed with trichloroacetic acid and methanol Were compared with those subjected only to freeze‐drying. Liquid scintillation counting was performed of total, non‐volatile, acid‐insoluble and dNA‐associated radioactivities. A rapid increase of the [3H]thymidine incorporation was seen during the first hour after the injection. Further prolongation of the survival time did not result in any significant increase of the incorporated radioactivity. Moreover, there were only slight differences between the autoradiograms from extracted and non‐extracted sections. Radioactivities asśociated with DNA closely eorrelated to those representing acid‐insoluble material, indicating that acid‐insoluble radioactivity provides a good estimate of the [3H]thymidine incorporation into DNA.
Negative Effect of Iodide On the Survival of Newly Divided Epithelial Cells In Chronically Stimulated Rat Thyroid
Authors: Rognoni J. B. , Penel C. , Golstein J. , Galand P. , Dumont J. E. 
Published: May 2008

Abstract. The aim of this work was to investigate some aspects of the thyroid epithelial cell kinetics during the iodide‐induced involution of a hyperplastic goitre in the rat. Rats were made iodine‐deficient for 6 months, and propylthiouracil (PTU) (0.15%) was added to the diet during the last 2 months. Thereafter, rats were refed with iodide and PTU was removed (day 0).Forty‐eight hours previously, all the rats were injected with tritiated thymidine ([3H]TdR) (1 μCi/g). Some animals were killed 1 hr or 24 hr after [3H]TdR injection (i.e. on day ‐2 and ‐1, day O corresponding to the restoration of a normal iodine diet); the other animals were killed after different delay periods and following L3H]TdR injection. Autoradiography of thyroid sections, iodine determination of plasma iodide and protein‐bound iodine (PBI), and RIA of plasma thyroid stimulatory hormone (TSH) were performed. Plasma TSH concentration was very high on day O of iodide refeeding (3000 ± 330 ng/ml) and remained at this level until day 8. Plasma PBI was very low on day O, remained so until day 4 and greatly increased on day 8. Plasma iodide was also very low on day O, but markedly increased on day 1, then did not vary significantly until day 43 of iodine refeeding. Thyroid weight, elevated on day O, decreased relatively quickly until day 30, then more slowly until day 73.
Cell Position Dependence of Labelling Thymidine Nucleotides Using the De Novo and Salvage Pathways In the Crypt of Small Intestine
Authors: Chwalinski S. , Potten C. S. 
Published: May 2008

Abstract. About twice as much tritiated thymidine ([3H]TdR) is taken up by cells at the bottom of the crypt of the small intestine as by the rapidly cycling mid‐crypt cells. However, the uptake of tritiated deoxyuridine ([3H]UdR) is even throughout the crypt.Exogenous thymidine is incorporated about four times and eight times more efficiently than deoxyuridine by the cells in the mid‐crypt and cells at the bottom of the crypt, respectively. However all S phase cells in the crypt appear to be capable of using either precursors, i.e. either the de novo or salvage pathway.Since methotrexate (1 or 5 mg/kg) inhibits (at 5 mg/kg completely) the uptake of [3H]UdR, but has no effect on [3H]TdR uptake, the de novo and salvage pathways appear to be independent. Within the precision of the methods used in the experiments the 3 hr inhibition of the de novo pathway of deoxythymidylic acid (dTMP) synthesis by methotrexate does not produce any increase in utilization of the salvage pathway measured by incorporation of [3H]TdR into DNA. the increased efficiency of thymidine utilization by crypt base cells is not attributable to (i) differences in accessibility of thymidine; (ii) differences in the rate of DNA synthesis or (iii) the size of the nuclei.
A trophic effect of epidermal growth factor (EGF) on rat colonic mucosa in organ culture
Authors: Finney K. J. , Ince P. , Appleton D. R. , Sunter J. P. , Watson A. J. 
Published: May 2008

Abstract. The development of an organ‐culture system for rat colonic mucosa has enabled a direct assessment of the effect of epidermal growth factor (EGF) on cell division. An augmented mitotic index (AIm) has been employed to identify changes in cell proliferation.Explants of colonic mucosa from four animals were maintained in a medium containing serum for five days. On the fifth day of culture, half of the explants received fresh medium containing EGF (40 ng/ml) and the remainder (controls) fresh medium only. At 6,12,24 and 48 hr thereafter groups of both experimental and control explants received the metaphase‐arresting drug vincristine (4 μg/ml) for 3 hr prior to fixation. The proportions of vincristine‐arrested metaphases within the explants were determined. Analysis of the data indicates that when serum is present exogenous EGF exerts a trophic effect which increases with time (P < 0.001).In a second experiment colonic explants from four animals were maintained for five days in a serum‐free medium and were then divided into groups, each of which received one of a range of concentrations of EGF. The AIm was determined for each group after 36 hr. It was found that increasing concentrations of EGF produce a small but significant increase in cell proliferation (P < 0.01). This effect, however, was less pronounced than that seen when serum was present.These results suggest that EGF has a trophic action on the colon and interacts with additional factors found in serum.