bluuebunny/crossref_metadata_2025_split huggingface dataset:
CYTOKINETIC ANALYSIS OF THE JB‐1 ASCITES TUMOUR AT DIFFERENT STAGES OF GROWTH
Authors: Dombernowsky P. , Bichel P. , Hartmann N. R. 
Published: May 2008

ABSTRACTThe cell kinetics of the murine JB‐1 ascites tumour have been investigated on days 4, 7 and 10 after transplantation of 2·5 × 106 cells. The experimental data, growth curve, percentage of labelled mitoses curves, continuous labelling curves and cytophotometric determination of single‐cell DNA content have been analysed by means of a mathematical model for the cell kinetics. The important result was the existence of 8% non‐cycling cells with G2 DNA content in the 10‐day tumour, while only 0·2 and 0% were observed in the 7‐ and 4‐day tumours, respectively. The doubling times determined from the growth curve were 22·8, 70 and 240 hr, respectively, in the 4‐, 7‐ and 10‐day tumours. Growth fractions of 76, 67 and 44% were calculated for the same tumour ages. The mean cell cycle time increased from 14 to 44 hr from day 4 to 7 due to a proportional increase in the mean transit time of all phases in the cell cycle. In the 10‐day tumour, the mean cell cycle changed to 41 hr and TG1 decreased to 0·5 hr. The cell production rate was 4·3%/hr in the 4‐day tumour, 1·2%/hr in the 7‐day tumour and 1·0%/hr in the 10‐day tumour. The cell loss rates in the same tumours were 1·3, 0·2 and 0·7%/hr, respectively. The analysis made it probable that the mode of cell loss was an age‐specific elimination of non‐cycling cells with postmitotic DNA content.
CHANGES OF LYMPHOCYTE KINETICS IN THE NORMAL RAT, INDUCED BY THE LYMPHOCYTE MOBILIZING AGENT POLYMETHACRYLIC ACID
Authors: Ormai S. , Hagenbeek A. , Palkovits M. , van Bekkum D. W. 
Published: May 2008

ABSTRACTThe changes in lymphocyte kinetics induced by the lymphocyte mobilizing agent polymethacrylic acid (PMAA) were studied in the normal rat. Quantitative data are presented concerning the degree of lymphocyte mobilization in the spleen and in various lymph nodes at different times after PMAA administration. Data were also obtained regarding the exact site of lymphocyte mobilization in the spleen. Evidence is given that PMAA mobilizes both T and B lymphocytes.Furthermore, results are presented on the different routes along which mobilized lymphocytes reach the blood. It is concluded that lymphocytes mobilized from the various lymph nodes are transported to the peripheral blood mainly by way of the efferent lymphatics (‘indirect’ route) while lymphocytes mobilized from the spleen will enter the blood chiefly via the so‐called ‘direct’ route.The relevance of these data to lymphocyte kinetics is discussed in relation to the planning of effective irradiation schedules for extra‐corporeal irradiation of the blood during induced lymphocyte mobilization.
KINETICS OF GROWTH OF HAEMOPOIETIC COLONY CELLS IN AGAR
Authors: Testa N. G. , Lord B. I. 
Published: May 2008

ABSTRACTCell kinetic parameters of mouse granulocytic and mononuclear cells growing in colonies in agar cultures have been measured. Analysis of flash and continuous labelling studies with 3H‐thymidine together with determinations of colony size, growth fraction and mitotic indices, gave the following values for the phases of the cell cycle: G1= 6·3 1·6 hr, S = 5·8 ± 1·4 hr, G2= 1·7 ± 0·1 hr and M = 0·7 ± 0·1 hr (42 ± 8 min). No difference in the cell cycle parameters of granulocytic and mononuclear cells were found in this study.Colonies of different size from cultures of the same age group had similar labelling indices, indicating that the size of a colony is not a function of the rate of proliferation of cells in the colony. Rather, variation in colony size is probably representative of an initial delay in the onset of colony development.
CELL KINETICS IN MOUSE THYMUS STUDIED BY SIMULTANEOUS USE OF 3H‐THYMIDINE AND COLCHICINE
Authors: Borum Kirstine 
Published: May 2008

ABSTRACTFollowing an injection of 3H‐thymidine to mice there is no initial incorporation in small thymocytes, only in larger ones. In the course of time small thymocytes aquire the label. Whether the delayed uptake in small thymocytes is due to a direct cell to cell transfer of labelled nuclear material from inititally labelled larger cells to small thymocytes, or whether it is due to small thymocytes being formed from larger cells by mitotic division was investigated by the administration of Colcemid® immediately after one injection of 3H‐thymidine. In the absence of cell division no labelled small thymocytes appeared with time. This finding does not support the idea of a cell to cell transfer of DNA; it rather lends support to the view that small thymocytes arise by mitotic division of larger cells in the thymus. During the treatment with Colcemid® the migration of cells took place from peripheral to central cortex just like under normal conditions.
DIFFERENCES IN REUTILIZATION OF THYMIDINE IN HEMOPOIETIC AND LYMPHOPOIETIC TISSUES OF THE NORMAL MOUSE
Authors: Feinendegen L. E. , Heiniger H. J. , Friedrich G. , Cronkite E. P. 
Published: May 2008

ABSTRACTSwiss Albino mice received a single i.v. injection of 3H‐thymidine (TdR) or of 125I‐deoxyuridine (IUdR). Bone marrow, thymus, spleen and mesenteric lymph node were examined for the efficiency of precursor incorporation into DNA, and for DNA renewal from day 1 to day 8.TdR is 5–8 times more efficiently incorporated by the different organs in vivo and in vitro than is IUdR. This indicates that the discrimination against IUdR occurs at the level of DNA synthesizing cells.A diminished DNA turnover rate measured with 3H‐TdR in comparison with 125I‐UdR is interpreted to indicate reutilization of TdR.TdR reutilization was observed in bone marrow and spleen from at least day 1 on, and in the thymus from day 3 on, following pulse labeling of DNA synthesizing cells. The degree of TdR reutilization appears higher in the thymus (67%) than the bone marrow (43%) and spleen (38%). The mesenteric lymph node indicates either no, or a very low efficiency of TdR reutilization. The data are also consistent with a reutilization equally efficient for TdR and IUdR.It is suggested that the TdR salvage pathway in hemopoietic tissues is largely localized to single organs which have immediate access to TdR made available by catabolism of DNA. The contribution of TdR from systemic reutilization to the organs studied falls within the limits of error of measurements. Moreover, the TdR salvage pathway especially in the lymph node may involve other DNA breakdown products than nucleosides.
HEMOPOIETIC CELL LINE‐SPECIFIC EFFECTS OF RENAL GRANULOPOIETIC FACTOR (GPF) ON TRANSPLANTABLE MOUSE MARROW STEM CELLS: COMPARISON WITH ERYTHROCYTE STIMULATING FACTOR (ESF) AND ENDOTOXIN
Authors: Delmonte L. 
Published: May 2008

ABSTRACTThe Till‐McCulloch spleen colony system was used to differentiate the time‐ and dose‐dependent effects of GPF (calf renal granulopoietic factor), ESF (erythrocyte stimulating factor) and Pyrexal (endotoxin from S. abortus equi) on the total and differential exocolonizing potential of treated donor mouse marrow cells. A single optimal dose of either hemopoietin given to the donor was found to activate transplantable colony forming units (CFU) of the hemopoietin‐specific cell line. There followed a series of time‐dependent oscillatory waves of specific CFU activation, the magnitude of which gradually dampened over a period approximating the stimulated cells’generation time. Flooding doses of GPF and ESF abrogated this phenomenon. Combination treatment with GPF and ESF cancelled out the cell line‐specificity of CFU stimulation, presumably due to the two hemopoietins’competition for a common stem cell. Multiple doses of GPF were found to potentiate the granulopoietic effects of a single dose of GPF, the response apparently being limited both by the magnitude of the stimulation and by the size of the available CFU pool(s). A single dose of Pyrexal failed to evoke a GPF‐like or ESF‐like CFU increase and shifted the marrow's differential exocolonizing potential in the direction of the erythrocytic cell line. The CFU response to GPF is thus qualitatively and quantitatively distinct from those evoked by ESF and endotoxin. The possibility is proposed that GPF may be specific for the granulocytic line at the level of the CFU compartment(s).
EFFECTS OF ISOGENIC BONE MARROW CELL DOSE ON ERYTHROKINETICS OF LETHALLY X‐IRRADIATED MICE
Authors: Smith L. H. , Goodman Joan W. , Hodgson George S. 
Published: May 2008

ABSTRACTThe effect of isogenic bone marrow cell dose on several parameters of hemopoietic regeneration in lethally X‐irradiated mice was studied. The appearance of 59Fe in red blood cells (RBC) and spleen, the hematocrits, and the spleen weights were measured at various times after irradiation and the injection of 105, 106, 107 or 108 marrow cells. Results show that with increasing cell dose, regeneration of erythropoiesis was detectable earlier, proceeded at a faster rate, reached a peak more quickly, and subsided to normal levels sooner. The initial spleen‐weight growth rate was independent of cell dose, although the onset of growth was earlier the higher the dose. The maximum rate of RBC production was attained earlier the larger the cell dose and was a decreasing function of the hematocrit at that time, which in itself was an increasing function of cell dose. These data support the concept of a proportional model for control of erythropoiesis as described by Hodgson (1970).The present data are interpretable in terms of an A‐ and B‐cell model for erythropoiesis as suggested by Lajtha, Gilbert & Guzman (1971). This model postulates a compartment of undifferentiated multipotent A cells and a compartment of differentiating erythropoietic B cells capable of amplification according to the need for RBC. Application of the present data to the A‐B cell model generates a tentative description of the changes in kinetics of amplification in the B‐cell compartment as the size of the A‐cell base is changed.
CYTOKINETIC STUDIES OF THE REGENERATIVE PHASE IN THE JB‐1 ASCITES TUMOUR
Authors: Dombernowsky P. , Bichel P. , Hartmann N. R. 
Published: May 2008

ABSTRACTThe cell kinetics of recurrent growth of the murine JB‐1 ascites tumour have been investigated 0 hr and 24 hr after aspiration of the main part of the tumour in the plateau phase of growth.The experimental data: growth curve, percentage of labelled mitoses curve and continuous labelling curves combined with cytophotometric determination of single‐cell DNA content were analysed using two alternative mathematical models for the cell kinetics.Investigations 24 hr after aspiration showed that the doubling time had decreased to 70 hr as compared with 240 hr in the plateau tumour. This was due to a release of non‐proliferating cells into the cell cycle, resulting in an increase in the growth fraction from 44% to 72%. The decrease in the doubling time was also due to a shortening of the mean cell cycle time from 41 to 20.5 hr.The analysis rendered it likely that the aspiration caused a shift in the mode of cell loss from an age‐specific elimination of old non‐cycling cells with post‐mitotic DNA content in the plateau tumour to an elimination of younger cells immediately after mitosis.Investigations from 0 to 10 hr after aspiration verified the release of non‐proliferating cells with both G1 and G2 DNA content into the cell cycle. The release was initiated from 3 to 6 hr after aspiration. 24 hr after aspiration the experimental data did not indicate any further transition.
COMPARATIVE PROLIFERATIVE KINETICS OF CELLS FROM NORMAL HUMAN EPIDERMIS AND BENIGN EPIDERMAL HYPERPLASIA (PSORIASIS) IN VITRO
Authors: Chopra D. P. , Flaxman B. A. 
Published: May 2008

ABSTRACTProliferation kinetics of epidermal cells from normal human skin and lesions of psoriasis (benign epidermal hyperplasia) were studied in vitro. Epithelial out‐growths were obtained from skin explants and the cell cycle studied using the conventional method of following two successive curves of labeled mitoses after an initial pulse with 3H thymidine. The length of Tc was 59 hr and 53.5 hr respectively for normal and psoriatic cells. The shorter Tc for psoriasis was due to a shorter duration of S. The growth fraction was 66% and 74% for normal and psoriatic cells respectively as determined by continuous labeling with 3H thymidine. Under the conditions of the present experiments, therefore, normal and psoriatic epidermal cells showed no significant difference in proliferative capacity.
EXISTENCE OF A SPERMATOGONIAL CHALONE IN THE RAT TESTIS
Authors: Clermont Yves , Mauger Annick 
Published: May 2008

ABSTRACTAdult rats with normal or X‐irradiated testes were used in an experiment to test the possible existence of a chalone in the testis. On the 11th day following irradiation, i.e. as the type A spermatogonia proliferated actively to restore the partially destroyed spermatogonial population, the animals with irradiated testes were subdivided into three groups. Rats of the first group were injected intraperitoneally with a saline extract of normal adult rat testes. Animals of the second group were injected with an equal amount of physiological saline while the rats of the third group received equivalent injections of a saline liver extract. Two additional groups of rats with non‐irradiated testes, injected with the testicular extract or saline solution, served as controls. Following the last injection all animals were injected with 3H‐thymidine and sacrificed. From each animal one testis was used to determine the specific radioactivity of its DNA, the other testis was processed for radioautography. The testicular extract produced a significant decrease in uptake of radioactivity by the irradiated testes. There was no difference in the radioactivity uptake by the testes of non‐irradiated rats. Correspondingly the labeling index of type A spermatogonia was significantly lower in animals of the first group than in the other two groups of animals with irradiated testes. However, there was no difference in the labeling indices of Intermediate and type B spermatogonia or of preleptotene spermatocytes in the animals receiving the extracts or the saline solution. In animals with non‐irradiated testes there was no difference in the labeling indices of type A or other types of spermatogonia or of spermatocytes. These data were taken to indicate that a saline extract of normal adult testes contains a substance that can inhibit specifically the proliferation of type A spermatogonia during the repair phase of the spermatogonial population following irradiation. This substance was tentatively considered as a spermatogonial chalone.
NON‐STEADY‐STATE ANALYSIS OF CELLULAR DEVELOPMENT
Authors: Wheldon T. E. , Kirk J. , Orr J. S. 
Published: May 2008

ABSTRACTA discrete, compartmental, representation is proposed for cellular development. Equations describing the kinetics of cellular development (with or without cell proliferation) are derived in both differential and integral form.Using an integral formulation, a method is proposed for the computation of compartment transit times (maturation times) which does not require the use of radioactive or other tracers. Although some restrictive conditions are imposed, the applicability of the method does not depend on strictly steady‐state conditions, nor on purely exponential growth or decay. The method permits analysis of cellular development in certain non‐steady cases for which existing analytical methods are inadequate.It is possible that patterns of cellular development during embryogenesis, recovery from insults, or growth in culture (e.g. of normal and leukaemic human granulocytes) could be examined using this method of analysis.
CORRELATION BETWEEN TISSULAR AND DIVISION FUNCTIONS IN THE LIVER OF YOUNG RATS
Authors: Barbason H. , Cantfort J. Van , Houbrechts N. 
Published: May 2008

ABSTRACTThe division and tissue specific functions are studied in the liver of young rats during the first post‐natal weeks. The division function is tested by the mitotic and the 3H‐thymidine labelling index, the specific tissular function by the cholesterol‐7 alpha‐hydroxylase activity. The nycthemeral rhythm is triggered simultaneously for the two functions at the 20th day of life. From this time, spontaneous or induced mitoses occur during the day (rest period) and the cholesterol‐7‐alpha‐hydroxylase during the evening (period of activity). The results are explained by the influence of the hypothalamoadrenal axis, which presents a circadian activity with a maximum in the evening.
ON THE MECHANISM OF THYROID MEDIATED MITOGENESIS IN ADULT ANURA. I. PRELIMINARY ANALYSIS OF GROWTH KINETICS AND MACRO‐MOLECULAR SYNTHESES, IN LENS EPITHELIUM, UNDER THE INFLUENCE OF EXOGENOUS TRIIODOTHYRONINE
Authors: Worgul B. V. , Rothstein H. 
Published: May 2008

ABSTRACTInjection of triiodothyronine into adult frogs leads to an increase in the mitotic index of a number of tissues. The work reported here shows that in one such tissue, lens epithelium, the mitogenic effect is chiefly due to an increase in growth fraction. Practically all of the cells in the population enter DNA synthesis (although not simultaneously) as a consequence of treatment.The administration of hormone also leads to an increase in intranuclear 3H actinomycin D binding. In addition 3H uridine and 3H amino acid incorporation rates rise as does microphotometrically detectable RNA and protein content.
PROLIFERATIVE RESPONSE IN THE RAT KIDNEY INDUCED BY A SINGLE, CARCINOGENIC DOSE OF DIMETHYLNITROSAMINE
Authors: Hard G. C. , Shaw D. M. 
Published: May 2008

ABSTRACTWith the application of autoradiography, the pattern of DNA synthetic activity in the rat kidney following a carcinogenic dose of DMN was traced during the 3 weeks following treatment. Depending on cell class and location, DNA synthesis was constantly depressed for the first 1 or 2 days throughout all zones of the kidney. Mesenchymal cells of the cortex and outer band of the outer medulla commenced a wave of stimulated activity at the third day with a peak of response at the sixth day. Epithelial cells of these same two zones were slower to respond, attaining a peak of DNA synthetic activity at the tenth day. By the start of the third week, activity had returned to normal or near‐normal levels. The observations are discussed in relation to the known morphological events which occur in the kidneys of DMN‐treated rats prior to the development of neoplasia.
SEPARATION OF PROLIFERATING CFU FROM G2 CELLS OF MURINE BONE MARROW
Authors: Monette Francis C. , Gilio Michael J. , Chalifoux Paul 
Published: May 2008

ABSTRACTThe technique of velocity sedimentation was employed to fractionate mouse bone marrow CFU‐s relative to two different phases of the cell cycle. CFU‐s in DNA synthesis which are destroyed by hydroxyurea were separated from other smaller CFU‐s which were shown to be insensitive to the drug and are presumably those CFU‐s in the G2 phase of cell cycle.
CELL SPECIFICITY OF CHALONE‐TYPE INHIBITORS OF DNA SYNTHESIS RELEASED BY BLOOD LEUCOCYTES AND ERYTHROCYTES
Authors: Bateman Angela E. 
Published: May 2008

ABSTRACTInhibitors of DNA synthesis released into balanced salt solution by rat erythrocytes and by rat leucocytes have been found to possess target‐cell‐specific properties which would be expected of chalones. When assayed in short‐term in vitro cultures the erythrocyte product reduced DNA synthesis (as measured autoradiographically) in erythroblasts present in populations of bone‐marrow cells but did not affect the DNA synthesis in myeloid or lymphoid cells. The leucocyte product, under the same culture conditions, reduced DNA synthesis in leucocyte precursor cells. The grain counts over nuclei of different cell types were recorded as well as the DNA labelling index. Results so far obtained cannot ascribe the erythrocyte‐chalone‐produced reduction in labelling index to a blockage of entry into S phase. This cell‐specific inhibitor may reduce continuing DNA synthesis in S phase cells to undetectable levels, compared with synthesis in control media. The leucocyte product, however, most probably prevents entry of leucocyte precursor cells into S phase.Possible relevance of these inhibitors as components of physiological control mechanisms or as therapeutic agents is discussed.
EXPRESSION OF CONGENITAL DEFECTS IN THE HAEMOPOIETIC MICRO‐ENVIRONMENT: PRE‐NATAL ERYTHROPOIESIS IN ANAEMIC ‘STEEL’(SljSlj) MICE
Authors: Cole R. J. , Tarbutt R. G. , Cheek E. M. , White S. L. 
Published: May 2008

ABSTRACTThe production of red cells by the livers of congenitally anaemic SljSlj foetal mice is reduced, so that the red cell concentration reaches only 0.4 × 109/ml, compared to 2.3 × 109/ml in normal littermates. The deficiency in haemoglobin concentration is not so severe (3 g/100 ml compared to 10 g/100 ml), because SljSlj red cells are macrocytic and normochromic. The number of erythroblasts in the livers of SljSlj foetuses is considerably less than in normal littermates, but the ratio of early erythroblasts to late erythroblasts is not altered. The cell cycles of SljSlj and normal early erythroblasts are similar, but the cycle time of SljSlj late erythroblasts is longer than that of the corresponding normal cells. SljSlj foetal liver cells have a restricted response to erythropoietin in vitro in terms of haem synthesis, whereas foetal liver cells of normal littermates are highly responsive until the 16th day of gestation. Mixtures of late 16 day SljSlj and normal foetal liver cells (both non‐responsive alone) respond to erythropoietin in vitro.
MEASUREMENT OF THE KINETIC STATUS OF BONE MARROW PRECURSOR CELLS: THREE CAUTIONARY TALES
Authors: Lord B. I. , Lajtha L. G. , Gidali Julia 
Published: May 2008

ABSTRACTMeasurements to determine the kinetic status of the morphologically unrecognizable haemopoietic precursor cells in the bone marrow are frequently carried out using techniques which inhibit or destroy cells in the DNA‐synthetic (S) phase of the cell cycle. For example, tritiated thymidine (3H‐TdR) has for many years been recognized as a highly specific label for DNA synthesis and, as such, administration of large doses of 3H‐TdR has often been used, both in vitro and in vivo, to kill cells in S. Assay of the surviving cells has then given a measure of the proportion of the total cells which are in the S‐phase of the generation cycle. Other compounds which have been used for the same purpose are: 125Iodo‐deoxyuridine (125I‐UdR), another S‐phase specific label, or hydroxyurea (HU) which prevents entry of cells into S and inhibits or kills cells already in S (Sinclair, 1965). For a variety of reasons, different laboratories tend to make different choices of the agent to be used for this purpose. As a result, it has sometimes proved difficult to marry data obtained from different sources. In the course of using 3H‐TdR, tritiated uridine (3H‐Ur), 125I‐UdR and HU in attempts toevaluate the kinetic status of bone marrow stem cells, it has become clear that their use is not straightforward and this paper presents data which illustrate some of the pitfalls associated with their use.
ORIGIN AND DIVISION OF LIVER MACROPHAGES DURING STIMULATION OF THE MONONUCLEAR PHAGOCYTE SYSTEM
Authors: Warr G. W. , Šljivić V. S. 
Published: May 2008

ABSTRACTThe ability of a range of mononuclear phagocyte system stimulants to induce proliferation of mononuclear cells in the liver, or to induce an influx of such cells from an extra‐hepatic source, was investigated in mice using techniques of whole or part‐body X‐irradiation and 3H‐thymidine incorporation. Results indicated that whereas stilboestrol, endotoxin, zymosan and Corynebacterium parvum all induced an influx of new, dividing, sinusoid‐lining cells into the liver, only zymosan and C. parvum were able, in addition, to induce proliferation of the pre‐existing cell population.