bluuebunny/crossref_metadata_2025_split huggingface dataset:
STEM CELL KINETICS IN THE L 5222 RAT LEUKAEMIA
Authors: Hoelzer D. , Harriss Ecleen B. , Jäger Christine 
Published: May 2008

ABSTRACTThe behaviour of normal haemopoietic stem cells of the bone marrow during the development of the acute transferable rat leukaemia, L 5222, has been investigated. The granulopoietic committed stem cells, measured by the in vitro colony technique, showed a marked decrease to less than half normal levels. Pluripotent stem cells included in the small lymphocytes of the bone marrow, and labelled with 3H‐thymidine by the complete labelling method, showed only a modest decrease in number and an unchanged labelling intensity. The results suggest that in this leukaemia the pluripotent stem cells may be affected in such a way that they are unable to react by proliferation to the depletion of the succeeding cell compartments. This might be due to inhibition by leukaemic cells or to a disturbed feedback regulation between the committed and pluripotent stem cell compartments.
OSCILLATION OF BLOOD MONOCYTE COUNTS IN HEALTHY INDIVIDUALS
Authors: Meuret Gerhard , Bremer Christel , Bammert Joachim , Ewen Jörg 
Published: May 2008

ABSTRACTDaily examinations of monocyte blood counts in healthy individuals indicated the presence of a monocyte cycle. The cycle length was between 3 and 6 days. The predominant period was 5 days. A similar oscillation frequency resulted from a computer simulation of a feedback loop which linked the blood monocyte compartment (controlled variable) to the stem cell differentiation rate (controlling variable).
AUTOSYNCHRONIZATION OF RAT LIVER CELLS WITH ENDOGENOUS CORTICOSTERONE AFTER PARTIAL HEPATECTOMY
Authors: Desser‐Wiest L. 
Published: May 2008

AbstractAfter adrenalectomy in adult male rats 3H‐TdR incorporation into the liver parenchymal cells is increased 4–8 times and the mitotic index rises from 0–31 % to 1–3%; this is inhibited by corticosterone. After hepatectomy the serum corticosterone level increases from 18 μg/100 ml to 57 μg/100 ml. The corticosterone binding capacity of the serum declines from 2–06 to 0–17. The activity of tyrosine transaminase doubles, whereas the incorporation of 3H‐TdR into the liver cells is decreased by a factor of 5–7. Thereafter the binding capacity increases again and reaches, 24 hr after operation, a value of 3–82. The tyrosine transaminase activity and the serum corticosterone content return to normal. 3H‐TdR incorporation, however, increases by a factor of 7‐7 of the initial value. We concluded that in the first few hours after partial hepatectomy corticosterone blocks the liver cells in G1 and an accumulation of the cells occurs at this cell cycle phase. Folio wing the binding of the corticosterone by serum proteins a little later the liver cells enter the S‐phase synchronously.
THE EFFECT OF CYTOSINE ARABINOSIDE IN VITRO ON AGAR COLONY FORMING CELLS AND SPLEEN COLONY FORMING CELLS OF C57BL MOUSE BONE MARROW
Authors: Millard R. E. , Okell S. F. 
Published: May 2008

AbstractThis study reports the effect of cytosine arabinoside in culture on two classes of bone marrow progenitor cells in C57BL mice, agar colony forming cells (ACU) and spleen colony forming cells (CFU). Both normal cells and rapidly proliferating cells were studied.The results show that in normal mice, 23 % of ACU but only 7 % of CFU are killed following 1 hr incubation with the drug. With longer periods of incubation, the survival of ACU in the controls is poor, and the results for the drug‐treated cultures suggest that the cells are held up in cycle. In continuously irradiated mice, the proportion of ACU and CFU killed after 1 hr incubation with drug is increased to 43–54%, confirming previous results that these cells are proliferating more rapidly than in normal mice. In mice treated with myerlan, 54 % of ACU are killed by 1 hr in vitro exposure to cytosine arabinoside, again confirming that ACU are rapidly proliferating. However, the proportion of CFU killed is lower (23 %).These results are compared with other studies of the effect of cytosine arabinoside in vivo and also with thymidine suicide in the same strain of mice. The results show that cytosine arabinoside has the same effect as tritiated thymidine, and also that the proportion of CFU killed by these agents in vitro is lower than when the agents are injected in vivo. It is suggested that the conditions in culture have an adverse effect on CFU, which cease DNA synthesis, and are protected from the killing effect of cytosine arabinoside and tritiated thymidine.Since cytosine arabinoside in vitro has an effect similar to tritiated thymidine in vitro on bone marrow progenitor cells in C57BL mice, in vitro incubation with cytosine arabinoside could be an alternative method to thymidine suicide for measuring differences in cell proliferation rate.
CHANGES IN CELL PROLIFERATION KINETICS OCCURRING DURING THE LIFE HISTORY OF MONOLAYER CULTURES OF A MOUSE TUMOUR CELL LINE
Authors: TWENTYMAN P. R. , WATSON J. V. , BLEEHEN N. M. , ROWLES P. M. 
Published: May 2008

AbstractFollowing inoculation of monolayer cultures of EMT6 mouse tumour cells at 105 cells, a short lag is followed by 3 days of exponential growth with a population doubling time of 12 hr. A plateau cell number is reached between days 4 and 5 and is maintained for at least 8 days. During exponential growth, the pulse 3H‐TdR labelling index is 55–60%, all cells are in cycle, and the median cycle time is 11–12 hr. For the first 3 days of plateau phase, the labelling index is about 25 % and there is considerable cell loss. The cell cycle is 32–40 hr, and S‐phase is very long. Later in plateau phase, the labelling index falls to <2 % and there is little cell loss.The changes in kinetics occurring in EMT6 cultures are discussed with reference to reported changes occurring in other cell lines.
CIRCADIAN INFLUENCE ON THE WAVE FORM OF THE FREQUENCY OF LABELED MITOSES IN MOUSE CORNEAL EPITHELIUM
Authors: Burns E. Robert , Scheving Lawrence E. 
Published: May 2008

AbstractThe FLM was studied in mouse corneal epithelium at two different phases of the mouse circadian system. The following results were obtained: (1) a circadian rhythm was found in the corneal mitotic index of both experimental groups, with the peak near 09.00 hours, the trough near 21.00 hours and a 10‐fold difference in values between the peak and the trough; (2) when 3H‐TdR was injected at 09.00 hours, the first wave of labelled mitoses rose earlier, attained a broader peak and fell later when compared to the first wave of labeled mitoses obtained when 3H‐TdR was injected at 21.00 hours; and (3) in both experimental groups there was a suggestion of a second wave of labeled mitoses, especially in the group injected with 3H‐TdR at 21.00 hours, where a flat second wave appeared in the region of 60–90 hr. Transit times derived from FLM curves obtained from such synchronous populations of cells are of questionable validity. Circadian rhythmicity and other causes of synchronization must be ruled out before accepting a single FLM curve as a valid indication of transit times.
RELATIONSHIPS BETWEEN CELL CYCLE DURATION, S‐PERIOD AND NUCLEAR DNA CONTENT IN ERYTHROBLASTS OF FOUR VERTEBRATE SPECIES
Authors: Grosset Lise , Odartchenko Nicolas 
Published: May 2008

AbstractErythroblasts of four vertebrate species (Triturus cristatus, Rana esculenta, Lacerta viridis and Gallus domesticus) differing markedly in their nuclear diploid DNA content, are used to study a possible relationship between cell cycle duration and DNA content. DNA is determined cytophotometrically and fluorometrically. The cell cycle is analysed by evaluating labelled mitoses after an injection of tritiated thymidine and also by double labelling with 14C‐ and 3H‐thymidine. A direct but non‐linear relationship is demonstrated between DNA content of erythroblast nuclei and the duration of DNA‐synthesis.
A COMPARISON OF COMPUTER METHODS FOR THE ANALYSIS OF FRACTION LABELLED MITOSES CURVES
Authors: Hartmann N. R. , Gilbert C. W. , Jansson B. , Macdonald P. D. M. , Steel G. G. , Valleron A.‐J. 
Published: May 2008

AbstractComputer methods developed by the authors for analysis of fraction labelled mitoses curves (FLM curves) have been compared. Four test examples were used in the study; the first example was the synthesis of a FLM curve with fixed parameters and the others involved fitting actual data. Experimental FLM curves showing various degrees of damping were used in the curve fitting tests. In each test example the comparison was based on the assumptions of exponential growth, a growth fraction of unity and no cell loss. In three of the test examples good agreement between the methods was observed but in one example some important discrepancies arose in the analysis of a heavily damped FLM curve.
INHIBITORY EFFECTS OF MITOGENS ON ADENOIDAL LYMPHOCYTES IN VITRO
Authors: Nitschke Ruprecht , Karon Myron 
Published: May 2008

AbstractCultures of human adenoidal lymphocytes exposed briefly to either phytohemagglutinin (PHA), Staphylococcus filtrate (Staph‐F), concanavalin‐A(Con‐A), or pokeweed mitogen (PWM) incorporate increased amounts of thymidine earlier than replicate cultures exposed continuously to the mitogens. These effects can begin in the first 24 hr of culture and are seen maximally between 36 and 72 hr. Once a blastogenic response is established, PHA or PWM can diminish that response. Inhibition with PWM requires that the initial stimulation was with this mitogen, while PHA can inhibit blastogenesis to both PHA and PWM‐stimulated cells. Because these mitogens can have a paradoxical effect on adenoidal lymphocytes, being capable of both initiating and inhibiting DNA synthesis, this phenomena should be kept in mind when such systems are utilized for the evaluation of antigens and drug effects.
RATE AND TIME OF DNA SYNTHESIS OF INDIVIDUAL CHINESE HAMSTER CELLS
Authors: Dörmer P. , Brinkmann W. , Born R. , Steel G. G. 
Published: May 2008

AbstractThe duration of DNA synthesis of a diploid cell line of Chinese hamster fibroblasts was determined in a comparative study by the FLM technique, and also by a new technique for measuring the rate of DNA synthesis of individual cells. These methods produced comparable results when applied during exponential growth of the cells. The rate of DNA synthesis was measured by means of quantitative autoradiography following a short‐term incubation of the cells with 5 × 10‐6 M FUdR and 10‐5 M 14C‐TdR. The choice of the medium for this purpose did not seem to be critical. The autoradiographic silver grains over cells and 14C‐standard sources are counted by microphotometry using incident light bright‐field. The direct measurements of DNA synthesis rate are ‘compartment’ statistics which have been converted into ‘flux’ parameters for comparison with the FLM method and applicability in cell‐kinetic calculations.Frequency distributions of the rate of DNA synthesis of individual cells thus obtained may resemble normal distributions quite closely. They result from several factors: differences in the rate of synthesis in different parts of the S‐phase, the density distribution of cells within the S‐phase, the variation in the time of DNA synthesis among individual cells, and the experimental error. In the case of a pronounced partial synchronization as probably has been present in one experiment performed in the lag phase, an incorrect time of DNA synthesis may result from the rate values. Due to the variation in DNA synthesis rate in different parts of the S‐phase it is not possible to determine the duration of DNA synthesis of an individual cell. However, the mean values of DNA synthesis time are reliable.The new method will be preferentially applied for determining the duration of DNA synthesis of human cells in as far as difficulties are encountered with the classical methods. In addition, it may be used to advantage for studying cells which make up low percentages in mixed populations. It finally permits a safer morphological classification of the cells under study than is possible with the classical methods.
THE PHOSPHORYLATION OF NUCLEAR PROTEINS IN THE REGENERATING AND PREMALIGNANT RAT LIVER AND ITS SIGNIFICANCE FOR CELL PROLIFERATION
Authors: Letnansky Karl 
Published: May 2008

AbstractIn liver regeneration or neoplastic transformation, phosphorylation of nuclear proteins is stimulated. In the regenerating liver all main histone fractions are involved in this process. The type of histone phosphorylated seems to be dependent on the position of the partially synchronized cells within the generation cycle. At a time when most cells are exhibiting maximum HnRNA‐synthesis, histone F2a2 belongs to those fractions with highly stimulated phosphate incorporation. Phosphorylation of this fraction alone is stimulated by cyclic AMP in parallel to a stimulation of HnRNA‐synthesis.The preneoplastic liver is characterized by oscillating phosphorylation and dephosphorylation reactions of nearly all histone fractions during the first days of N‐nitroso‐diethylamine administration. After 2 months of carcinogen feeding a 50–150% stimulation of the phosphorylation of Fl subfractions is observed. The phosphate content of the other histones, however, has returned to the original level.A series of further proteins, isolated together with the histones, show very similar phosphorylation characteristics. These proteins are mostly of non‐histone origin. It is suggested that some of them are responsible for the transport of RNA with messenger properties within the cell.
ERYTHROID AND GRANULOCYTE‐MACROPHAGE PROGENITOR CELLS IN PRE‐NATAL ‘STEEL’ (SlJ/SlJ) ANAEMIC MICE
Authors: Cole R. J. , Regan T. , White S. L. , Cheek E. M. 
Published: May 2008

AbstractThe erythropietin sensitivities of dissociated cell cultures and explanted fragments of fetal livers of congenitally anaemic SlJ/SlJ mice, and their normal littermates, have been compared. The erythropoietin responsiveness of SlJ/SlJ foetal liver cells is deficient in both types of culture.The maximum liver complement of erythroid colony forming cells (CFUe) occurs on the 16th day of development when ‘normal’ livers contain approximately 6 × 105 erythroid colony forming cells/liver. In SlJ/SlJ fetuses the maximum reached is only 1 × 105. Granulocyte‐macrophage colony forming cells (CFUC) in SlJ/SlJ fetal livers are also reduced to approximately 60% of normal numbers. Erythroid colony forming cells are also reduced in the spleen and femoral bone marrow of SlJ/SlJ mice in the 2–3 days preceding birth. Granulocyte‐macrophage colony forming cells are rare in the femoral marrow of pre‐natal SlJ/SlJ mice, but their production in the SlJ/SlJ pre‐natal spleen appears unaffected.
ANALYSIS OF TIME DEPENDENT CHANGES OF LYMPHOPOIETIC ACTIVITY IN ORGAN CULTURES OF EMBRYONIC CHICKEN THYMUS
Authors: JUhlin Roger , Alm Gunnar V. 
Published: May 2008

AbstractThe time dependent development of lymphocytes in organ cultures of the thymus obtained from 10‐day‐old chick embryos was characterized by an initial phase of exponential increase of the number of lymphocytes per thymus followed by a plateau phase with no further increase in cell number. The proportion of cells in DNA synthesis dropped rapidly during the first 10 days of culture. Simultaneously the lymphocytes turned progressively smaller, as evidenced by both cell diameter and dry mass and constituted a homogeneous population of small cells at the end of the culture period.Thymic anlagen partially depleted of lymphoid precursor cells by a short hot pulse with 3H‐TdR showed a prolonged exponential phase and reached normal plateau cell numbers 2–4 days later than usual.Furthermore, at least in the first part of the plateau phase, a reduction in the number of lymphoid cells per thymus resulted in a recovery in terms of the cell number which was associated with increased DNA synthesis.These results are compatible with the regulation of thymic lymphopoiesis in organ culture through a mechanism operating via cell density.
MATRIX SIMULATION OF DUODENAL CRYPT CELL KINETICS
Authors: Roti Joseph L. Roti , Dethlefsen Lyle A. 
Published: May 2008

ABSTRACTSteady state crypt cell kinetics have been simulated using matrix algebra. The model crypt cell population is distributed through two proliferation compartments (P1 and P2) and a quiescent state (Q). Under steady state conditions half the daughter cells produced on completion of P1 enter G1 of P2 and half enter G1 of P1. Both P2 daughter cells enter Q. Cells in Q are non‐dividing but retain the potential to divide. On completion of Q, cells lose the potential to divide and move up onto the villi. The model has been developed by simultaneously simulating the following biological data: (1) the per cent labeled mitosis (PML) curve, (2) the number of labeled cells per crypt as a function of time following an injection of 3H‐thymidine, and (3) the total number of cells per crypt.
AGE DEPENDENCE OF THE NUMBER OF THE STEM CELLS IN HAEMOPOIETIC TISSUES OF RATS
Authors: VACEK ANTONÍN , BARTONÍĈKOVÁ ALENA , TKADLEĈEK LUDVÍK 
Published: May 2008

AbstractThe number and concentration of haemopoietic stem cells in the femoral bone marrow and spleen of Wistar rats of different ages were investigated. Stem cells were assayed by the spleen colony technique in irradiated rat recipients. The ability of the recipient spleen to harvest transplanted tissue as a macroscopic colony was found to be dependent on the recipient's age. Changes with senescence were observed also in the concentration and the size of the stem cell compartment both in the marrow and spleen. No differences were demonstrated in the seeding of transplanted colony‐forming units into the spleen of recipients of 1 and 4 months of age. A rats‐mice strain difference in the effect of senescence on the haemopoietic stem cells is discussed.
KINETICS OF HAEMOPOIETIC RECOVERY IN ENDOTOXIN‐TREATED MICE
Authors: Lahiri S. K. 
Published: May 2008

AbstractKinetics of mouse spleen colony forming units were studied after intra‐peritoneal injection of 1 μ/g body weight bacterial endotoxin S. typhosa. When these mice were used as unirradiated and sublethally irradiated donors, it was possible to study the effect of the endotoxin injection upon the cells. Use of the treated mice as irradiated recipients of normal cells gave information about the host effect.In treated unirradiated mice, the total nucleated cell and the CFU counts were disturbed, and 2 days later a large fraction of the CFU were found in the DNA synthesis (S) phase. This meant that injection of endotoxin generated factors affecting the kinetics of the CFU and triggering the resting CFU into the proliferative cycle. If then the mice were given supralethal irradiation and used as recipients of normal bone marrow cells, more CFU seeded to the spleen as compared to normal recipients; but the dip and the growth rate of the CFU were not changed. Hence the endotoxin‐generated factors had been eliminated in 2 days.A total body sublethal irradiation by 400 rad X‐ray 2 days after endotoxin injection reduced the post‐irradiation dip in the recovery curve of the CFU, indicating that though the factors affecting the cell kinetics had been eliminated, the cycling CFU behaved like a growing population. During the first week, the growth rate of the CFU remained the same as in control irradiated mice. The growth rate of the spleen CFU of the endotoxin‐treated mice slowed down during the second week, and their self‐replicating ability was low. Fluctuations in the DNA synthesizing fraction of the spleen CFU suggested a variability in the ratio of the length of the S phase and the cell generation time.
A SERUM FACTOR INDUCING MONOCYTOSIS DURING AN ACUTE INFLAMMATORY REACTION CAUSED BY NEWBORN CALF SERUM
Authors: van Waarde Dick , Hulsing‐Hesselink Elizabeth , van Furth Ralph 
Published: May 2008

AbstractAn intraperitoneal injection of newborn calf serum (NBCS) into CRF Swiss mice causes an inflammatory reaction characterized by an increase in the number of macrophages in the peritoneal cavity and a concomitant monocytosis. The serum of such mice contains a monocytosis‐inducing factor, as demonstrated by the intravenous injection of serum collected 18 (CalS 18) and 24 hr (CalS24) after the intraperitoneal injection of NBCS. Serum from normal untreated mice, from mice given an intraperitoneal injection of sterile pyrogen‐free saline, which does not cause an inflammatory reaction, or from mice 72 hr after an intraperitoneal injection of NBCS, when the inflammatory reaction has subsided, does not cause a monocytosis in test mice.Intravenous injection of CalS 18 causes not only a monocytosis but also an increase in the number of promonocytes and bone marrow monocytes, suggesting an increased production of monocytes.The effect of CalS 18, CalS24 and CalS 18 filtrate is specific for the mononuclear phagocytes, since only non‐significant increases in the numbers of lymphocytes and granulocytes were observed. The active factor in CalS 18 was shown to be different from the monocytosis‐inducing factor present in NBCS.The monocytosis‐inducing factor in CalS 18 passes through an ultrafiltration membrane with an exclusion limit of 50,000 Daltons, so that the molecular weight must be below this value.
PREFERENTIAL LABELING OF RAT LYMPHOCYTES WITH A RAPID RATE OF TURNOVER BY TRITIATED DEOXYCYTIDINE
Authors: Amano M. , Everett N. B. 
Published: May 2008

AbstractLymphocytes in thymic cortex and germinal centers of lymphoid tissues are labeled intensely with generally labeled tritiated deoxycytidine [G‐3H]dCyd whereas they are weakly labeled with methyl tritiated deoxythymidine [methyl‐3H]dThd of the same specific activity, not only by single injection but also by an intensive injection schedule. [G‐3H]dCyd can be used to label short‐lived lymphocytes strongly, although not specifically. The distribution patterns of labeled lymphocytes were different depending on the injection schedules of [G‐3H]dCyd. [G‐3H]dCyd can be used as a precursor molecule for cytosine and also thymine found in DNA. The ratios of radioactive thymine to cytosine measured biochemically on DNA extracted from radioactive lymphocytes labeled by the various schedules indicate strongly that short‐ and long‐lived lymphocyte populations have different abilities to utilize pyrimidine nucleosides for DNA synthesis.
THE RODENT INCISOR TOOTH PROLIFERON
Authors: Zajicek G. 
Published: May 2008

AbstractThe rodent incisor tooth is the site of five cell populations proliferating in harmony: amelocytes, odontocytes, pulp cells, endothelial cells and the periodontal ligament. Their proliferating regions are located in the apex tip, where the various cells originate. Cells displaced from the tooth origin at the apex toward the periphery, mature to perform their specified function. The proliferative events in the tooth are summarized in a conceptual model of the incisor proliferon. The proliferon is an oriented structure with an origin and periphery. It consists of four basic elements: parenchyma, connective tissue, blood vessels and nerve fibres, all interacting continuously. All four are indispensable in the definition of the proliferon.
CHANGES IN LIVER CELLS PLOIDY OF YOUNG RATS FOLLOWING ISOPRENALINE TREATMENT
Authors: Gerzeli G. , Barni S. 
Published: May 2008

AbstractCell proliferation induced by isoprenaline (IPR) stimulation in very high doses was assayed in the liver of young rats, and the formation of polyploid cells was studied from the 15th to the 70th day of life.A general stimulatory effect on a complex process of cellular multiplication, leading to a population of tetraploid cells, was found to be accelerated; the earlier appearance of binucleate cells and the subsequent significant variations in their incidence confirmed the role of this cell type as an intermediate step in the process of polyploidization. Evidence was found of concomitant size changes of the hepato‐cytes, which might be partially independent of the effect on DNA content.The stimulation was no longer evident 20–30 days from the end of treatment, by when the cells which had come into contact with IPR should have completed the whole sequence of events leading to the formation of tetraploid mononucleate cells.