bluuebunny/crossref_metadata_2025_split huggingface dataset:
KINETICS OF ERYTHROPOIETIN STIMULATED PROLIFERATION OF ERYTHROID PROGENITORS IN THE SPLEEN
Authors: Hasthorpe S. , Hodgson G. 
Published: May 2008

ABSTRACTThe effect of RBC transfusion and erythropoietin (EPO) on the proliferation of immature erythrocyte progenitors was studied in the spleens of RBC transfused, lethally irradiated mice injected with bone marrow. Transfusion decreased expansion of the progenitors and slowed their proliferation: the mean cycle time as measured by per cent labelled mitosis (PLM) on the third day after injection of bone marrow was 10.7 hr in transfused as compared to 5.6 hr in non‐transfused mice. One injection of five units of erythropoietin on day 2 decreased the mean cycle time to 7.3 hr in transfused mice and increased expansion of the progenitor cells. The effects of erythropoietin on cell proliferation were prompt: a significant increase of incorporation of 3H‐TdR into DNA occurred within 2 hr of injection.Erythroblasts were absent from the spleens of transfused, irradiated bone marrow injected mice; however, erythroblasts appeared by 72 hr and 48 hr following EPO injection either 2 days or 5 days after transplantation respectively. Increased uptake of radioactive iron in spleen after erythropoietin injection preceded the appearance of erythroblasts by 2 and 1 days when erythropoietin was injected either 2 or 5 days after marrow transplantation respectively.The increase in cellular proliferation induced by erythropoietin in transfused irradiated mice injected with bone marrow equivalent to 0.35 femoral shaft was manifested as an increase of the total DNA content in the spleen by 119 μg (11.9 × 106 cells) within 48 hr of injection. The cellular increment produced by EPO injection on day 5 to mice given 0.05 femoral shaft consisted mainly of undifferentiated mononuclear cells, most of which were labelled, with erythroblasts comprising only one quarter of the increment. Erythropoietin inactivated by mild acid hydrolysis failed to increase cellular proliferation.
MOBILIZATION OF B AND T LYMPHOCYTES AND HAEMOPOIETIC STEM CELLS BY POLYMETHACRYLIC ACID AND DEXTRAN SULPHATE
Authors: Ham A. C. van der , Benner R. , Vos O. 
Published: May 2008

ABSTRACTThe leucocytosis which can be evoked by the polyanions dextran sulphate (DS), polymethacrylic acid (PMAA) and the copolymer of PMAA and styrene (PMAA—STYR) was studied in mice. After intravenous administration of these polyanions peak numbers of leucocytes were found in the peripheral blood 3 hr after injection. All three types of polyanions increased the number of lymphocytes, granulocytes and monocytes. Dose—response studies revealed that the nature of the polyanion determined the degree of leucocyte mobilization. The most potent mobilizer was found to be DS. This polyanion could evoke a six‐fold increase of the number of peripheral blood leucocytes.By means of the membrane fluorescence technique it could be demonstrated that optimal doses of DS, PMAA and PMAA—STYR mobilized both B and T lymphocytes. The ratio between the number of B and T cells mobilized was greater for DS than for the other two polyanions.Intravenous injection of DS, PMAA and PMAA—STYR also increased the number of circulating haemopoietic stem cells (CFU‐S). The most potent stem cell mobilizer appeared to be PMAA—STYR. This polyanion evoked a twenty‐five‐fold increase in the number of CFU‐S.
ESTIMATION OF THE MIGRATION OF THORACIC DUCT LYMPHOCYTES TO NON‐LYMPHOID TISSUES
Authors: Rannie G. H. , Donald K. J. 
Published: May 2008

ABSTRACTThe distribution of radioisotopes in tissues was measured following i.v. injection of labelled thoracic duct lymphocytes into syngeneic rats. The rate of elution of an isotope from the labelled cells and the subsequent fate of the eluted isotope were shown to be the most important factors limiting the usefulness of such isotopes for measuring cell localization particularly in non‐lymphoid tissues. Comparison of labelling procedures using [3H] and [14C]uridine, [3H] and [14C]leucine, [75Se]‐L‐selenomethionine, [99mTc]sodium pertechnetate and [51Cr]sodium chromate in vitro and [3H]thymidine in vivo showed that 51Cr had the fewest disadvantages in the present context. Using 5ICr‐labelled cells, the radioactivity was measured in a wide range of non‐lymphoid tissues, and estimates of cell traffic were obtained. In skin, for example, the results indicate a cell flux in the range of 104‐105 lymphocytes/gm/hr. Evidence is presented which suggests that the early substantial localization of labelled cells in the lung is not an artefact due to sequestration or embolization of traumatized cells but probably reflects a slow intravascular transit time through this capillary bed. The primary lymphoid organs, thymus and bone marrow were shown to include a subpopulation of lymphocytes which belong to the recirculating pool. The thymus always contained a greater concentration of radioactivity at 24 hr than all non‐lymphoid tissues except liver and kidney (approx. 0‐1% of the recirculating lymphocyte pool) and the bone marrow was capable of temporarily accepting a substantial proportion (approx. 25%) of the injected cells.
THE EFFECT OF INTESTINAL RESECTION ON THIRY‐VELLA FISTULAE OF JEJUNAL AND ILEAL ORIGIN IN THE RAT: EVIDENCE FOR A SYSTEMIC CONTROL MECHANISM OF CELL RENEWAL
Authors: Hanson W. R. , Rijke R. P. C. , Plaisier H. M. , Ewijk W. Van , Osborne J. W. 
Published: May 2008

ABSTRACTLocal and systemic control mechanisms have been postulated to explain the maintenance of steady state cell renewal in intestinal epithelium. Permanent alterations of cell renewal resulting in a new steady state imply alterations in control. Intestinal resection appears to cause such alterations resulting in hyper‐plasia of the residual intestine. To test the hypothesis of a systemic control, the effect of 60% mid‐intestinal resection on Thiry‐Vella fistulae of both jejunal and ileal origin was observed in rats. Results showed that hypoplasia occurred in fistulae without resection of the remaining intestine in continuity. Cell counts of crypt and villus columns and tritiated thymidine uptake in isolated whole crypts were reduced. Scanning electron microscopy showed marked hypoplastic alterations in villi. However, when 60% of the intestine in continuity was resected, hyperplasia occurred not only in the residual intestine but in the fistulae of both jejunal and ileal origin. Cell counts of villus and crypt columns were increased along with increased tritiated thymidine uptake per crypt. Neutral cc‐glucosidase and non‐specific esterase activities did not change as a result of resection but the activities of both enzymes were greater in ileal fistulae than in ileum in situ. Observations on the different resection response of the jejunal versus ileal fistulae lead to a distinction between inherent and induced differences within the small intestine. This study suggests a systemic control of cell renewal. A possible mechanism involving intestinal vascular physiology is discussed.
PREDICTION OF THE COMPLETE GROWTH PATTERN OF HUMAN MULTIPLE MYELOMA FROM RESTRICTED INITIAL MEASUREMENTS
Authors: Brunton G. F. , Wheldon T. E. 
Published: May 2008

ABSTRACTA method is presented for predicting the complete growth pattern of human IgG multiple myeloma from a few initial measurements of tumour cell number. This permits identification of patterns of undisturbed neoplastic growth in individual patients whose therapy cannot ethically be withheld for long periods. Since the unperturbed growth pattern is a necessary part of the information required for the prediction of individual patient response to alternative treatment schedules, the prospects for improved treatment of human multiple myeloma by optimal scheduling of drug administration are greatly increased.
AN AUTORADIOGRAPHIC STUDY OF THE 3H‐URIDINE AND 3H‐THYMIDINE INCORPORATION IN THE REGENERATING MOUSE LIVER
Authors: Lorup Christina 
Published: May 2008

ABSTRACTAn autoradiographic study was made of the 3H‐uridine incorporation into RNA and DNA in nucleus and cytoplasm of parenchymal cells in the regenerating liver of the mouse after a pulse time of 2 hr.After a decreased uptake of precursor into the parenchymal nucleus during the first 6 hr compared with the normal value, incorporation increased and was maximal at 36 hr; normal values were restored at 72 hr. The cytoplasmic labelling, after an initial small decrease, reached a maximum at 12 hr; this changed to normal 48 hr after hepatectomy. RNase‐digestion of the liver sections left a small incorporation in both nucleus and cytoplasm: presumably DNA. This incorporation is maximal at 12 hr over the nucleus and at 24 hr over the cytoplasm.After a 2 hr pulse of 3H‐thymidine, there was a marked uptake of the precursor into DNA about 24 hr after hepatectomy. This was maximal at 48 hr and reached normal values at 72 hr. A small amount of incorporation of 3H‐thymidine into DNA was seen immediately after the operation, and this population of weakly labelled nuclei was still rather large 72 hr later.
RESPONSIVENESS TO HUMORAL FACTORS OF MOUSE MARROW COLONY FORMING CELLS AFTER TREATMENT WITH CYCLOPHOSPHAMIDE
Authors: Gordon M. Y. 
Published: May 2008

ABSTRACTHumoral factors affecting granulopoiesis have been detected by culturing bone marrow cells in intraperitoneal diffusion chambers. This study investigated the possibility that treatment with drugs alters the ability of cells to respond to these factors.Three days after treatment with 200 mg kg‐1 cyclophosphamide, donor marrow cells were more responsive than normal cells to the factors produced in cyclophosphamide pretreated hosts. The optimum timing of host pretreatment for maximum colony stimulation also differed for cells from cyclophosphamide treated and untreated donors and these effects were found to depend on the dose of drug given to the animals.
Effect of Myleran On Murine Hemopoiesis
Authors: Delmonte L. 
Published: May 2008

ABSTRACTTime‐ and dose‐dependent patterns of depletion and regeneration of hemopoietic progenitor cells in mouse femora and spleens following treatment with the antileukemic agent Myleran (Busulphan, MY) were studied using the murine spleen colony system and the agar gel in vitro colony system. MY was found to depress granulopoiesis selectively, as manifested by the development of marked prolonged neutropenia, hypoplasia of the bone marrow and (to a lesser degree) of the spleen, reduction of the incidence of multipotential hemopoietic progenitor cells (CFU‐S) and of granulocytic progenitor cells (CFU‐C) in both femora and spleens, and impairment of the capacity of CFU‐S from either tissue to generate granulocytic colonies in the spleens of irradiated hosts. the severity and duration was greatest at high dose levels of MY (800 μ). the action of MY on CFU‐S was more pronounced than that on CFU‐C, suggesting that MY is a cycle‐independent agent. Repopulation of the CFU‐C pool preceded that of the CFU‐S pool. Development of neutropenia and maximal marrow hypoplasia followed the onset of depression of CFU‐S and CFU‐C incidence, while recovery of normal nucleated cellularity in the blood, femur and spleen preceded repopulation of the CFU‐S and CFU‐C pools. MY treatment resulted in transitory stimulation of colony stimulating factor (CSF) generation by the femur but had no effect on serum CSF levels. the peak of femoral CSF generation coincided with the nadir of CFU‐C depression. These findings indicated that the prolonged neutropenia following MY treatment was secondary to depletion of the progenitor cell pools, that during recovery granulopoietic repopulation took precedence over self‐maintenance of the hemopoietic progenitor cell pools, and that increased generation of CSF may play a role in the early phase of granulopoietic recovery.
Effect of Myleran On Murine Hemopoiesis
Authors: Delmonte L. 
Published: May 2008

ABSTRACTThe direct and host‐mediated effects of the antileukemia agent Myleran (Busulphan, MY) on murine hemopoietic progenitor cells was assessed in vivo in the differential spleen colony system and in vitro in the agar gel granulocytic colony system. MY destroyed both spleen colony forming cells (CFU‐S) and agar gel colony forming cells (CFU‐C), the effect on CFU‐S being ten‐fold more severe than that on CFU‐C. Moreover, MY indirectly enhanced the seeding efficiency of CFU‐S and directly impaired their capacity to self‐replicate. MY also acted both directly and indirectly to impair the capacity of CFU‐S to generate granulocytic spleen colonies. Both the direct and indirect effect of MY on the CFU‐S' differential spleen colony forming bias was maintained following their retransplantation into lethally irradiated hosts that had not been exposed to MY. Finally, MY acted indirectly to impair the capacity of CFU‐S to differentiate to CFU‐C. the phenomenon appeared to be humorally mediated, since it was induced by exposure of CFU‐S to the MY‐treated host environment but not by their exposure to the MY‐damaged splenic stroma. an effect on the CFU‐S themselves does not appear to have been involved, since impairment of CFU‐C generation could be reversed by retransplantation of the CFU‐S into lethally irradiated hosts that had not been exposed to MY. the findings were compatible with the concept that MY (a) affects the membrane permeability of CFU‐S to modulating agents such as hemopoietins, and/or (b) selectively enhances survival of a subpopulation of erythrocytically committed CFU‐S, and/or (c) selectively abrogates survival of a subpopulation of cells capable of inhibiting commitment to the erythroid cell line.
Comparison of the Effects of Epidermal Chalone In Young and Aging Mice
Authors: Leith J. T. 
Published: May 2008

ABSTRACTThe ability of epidermal chalones to produce inhibition of epidermal mitotic and DNA synthetic activities was investigated in young (2 month old) and old (27 month old) mice. Extracts of epidermal chalone were prepared from the skin of mice of these different ages, and these extracts were then tested for their inhibitory capacities against the same age group from which they were extracted, and also against the mice of the other age group. It was found that the ability of mouse skin to produce tissue‐specific agents with mitotic and DNA‐synthetic inhibitory capabilities did not change significantly with increasing age. There were however, decreases in both the labeling and mitotic indices with aging in untreated mice. These data suggest that chalone‐type inhibitory mechanisms are not primarily responsible for the increased cell cycle times seen to occur with aging in normal tissues.
Purification of Immunosuppressive Factors Extracted From Bovine Spleen (Lymphoid Chalone)
Authors: Lenfant Maryse , Garcia‐Giralt E. , Thomas M. , Di Giusto Laurette 
Published: May 2008

ABSTRACTA low molecular weight immunosuppressive factor FA which is able to reduce the blastic transformation capacity of lymphoid cells from treated mice has been characterized. It was prepared from a bovine spleen acetone powder and found to be associated partly with high molecular weight carriers in the form of an active complex characterized previously as part of a ‘lymphoid chalone’ fraction. FA may be obtained by selective ultrafiltration of F followed by P‐2 Biogel chromatography of the ultrafiltrate. Thymidine, deoxyinosine and deoxycytidine have been identified as the major constituents of FA by mass spectrometry, ultraviolet absorption data and thin layer chromatography. However, none of these nucleotides has the biological activity of FA.
Purification of Immunosuppressive Factors Extracted From Bovine Spleen (Lymphoid Chalone)
Authors: Garcia‐Giralt E. , Lenfant Maryse , de Garilhe M. Privat , MAYADOUX EVELYNE , MOTTA R. 
Published: May 2008

ABSTRACTA highly purified extract from bovine spleen (FA) possessing immunosuppressive capacity was studied. Its tissue specificity was analysed in vivo and in vitro and the main components of FA, the well‐known nucleosides deoxycytidine, deoxy‐inosine and thymidine, were tested in vivo.It seems that the molecule responsible for the biological activity of FA is a new substance endowed with strong specific activity and that lymphoid tissue is highly sensitive to the inhibiting capacity of this purified fraction.
Effect of Hyperthyroidism On Haemopoietic Stem Cell Kinetics In Mice
Authors: Vacek A. , Rotkovská D. , BartoniČková A. , Pospísiil M. 
Published: May 2008

ABSTRACTChanges in the pool of haemopoietic colony‐forming units (CFUs) of bone marrow and spleen were studied in experiments with mice fed dried thyroid gland (TH) for 21 days, and during the 13 days that followed feeding. After HU treatment, the number of CFUs in DNA synthesis was estimated. As early as the second day of TH treatment, the pool of CFUs is gradually increased, leading to an increase in the total number of splenic and bone marrow CFUs persisting after TH treatment for the period examined. Simultaneously, the numbers of nucleated cells in the bone marrow and spleen are increased. During TH feeding and following its termination, the total number of erythrocytes and the haematocrit values did not change significantly, whereas an increased number of leucocytes was observed in the peripheral blood after TH treatment. Elevation of the proliferative activity of CFUs occurred early in the period of TH treatment, with the maximum attained by end of the first week of TH feeding. This suggests a rapid response of the haemopoietic stem cell compartment to the administration of TH hormones. the participation of humoral factors controlling CFUs compartments in the mechanism of the stimulatory effect of TH hormones on haemopoietic stem cells is discussed.
Enhanced Post‐Irradiation Recovery of the Haemopoietic System In Animals Pretreated With A Variety of Cytotoxic Agents
Authors: Millar J. L. , Blackett N. M. , Hudspith B. N. 
Published: May 2008

ABSTRACTIt is known that pretreatment of mice with bacterial endotoxin and certain stathmokinetic agents between 1 and 3 days prior to exposure to ionizing radiation reduce radiation lethality. In this communication it is shown that pretreatment with cytosine arabinoside, methotrexate, nortestosterone and chlorambucil reduces radiation (1000 rad) induced lethality. This reduction can be ascribed to enhanced regeneration of the haemopoietic system in pretreated animals and not to increased survival of colony‐forming cells (CFU) in these animals. Regeneration of CFUs was underway within 24 hr after 900 rad in the pretreated mice but did not start until day 3 in mice treated with γ radiation only. Two agents, namely radiation itself (either 75 or 150 rad) and busulphan (10 mg/kg) did not reduce the lethal effects of subsequent γ irradiation nor enhance the regeneration of CFUs, even though radiation, like the protective cytosine arabinoside, induces early CFUs proliferation.The administration of nucleoside precursors of DNA enhanced regrowth of haemopoietic stem cells to an extent comparable with that of the most effective pretreatment, cytosine arabinoside. It is postulated that drugs like cytosine arabinoside operate by causing cell death, providing a source of DNA that can enhance the regrowth of surviving stem cells in the bone marrow.
REGRESSION of the MOUSE PAROTID GLAND INDUCED WITH ISOPROTERENOL
Authors: Domon M. , Okano T. , Sasaki T. , Nakamura T. 
Published: May 2008

ABSTRACTAcinar cells in rodent salivary glands are induced into one cycle of cell proliferation by a single injection of isoproterenol (IPR) (Baserga, 1970). Repeated injections of animals with IPR lead these cells to a few cycles of cell proliferation and then hypertrophy, when IPR stimulated proliferative response is lost and enlargement of the glands occurs. Without further IPR injections the enlarged glands regress to a normal size (Barka, 1965; van den Brenk, Sparrow & Moore, 1970). the present communication concerns the regression, or disappearance and reappearance, of the acinar cells which respond to IPR treatment.The parotid responds more readily to IPR in respect of cell proliferation and gland enlargement than the submaxillary gland (Baserga, 1970) and so was used in all studies. to produce full cell proliferation in the parotid, male SWR mice aged 3 months were given four injections at 48 hr intervals of DL‐isoproterenol‐HC1 (Sigma, St Louis, Missouri) at the dose of 7.5 mg per 30 g body weight. In the following description day zero refers to the date of fourth IPR injection. the parotid was then dissected out from animals at various days, and carefully freed of lymph nodes and fat tissues under a dissecting microscope. DNA content per gland (extracted by the method of Scott, Fraccastoro & Taft, 1956; Sasaki & Toda, 1972) increasea with the number of IPR injections, reaching a maximum after the fourth (Furuno, Iwasaki & Matsu‐daira, 1974), and then reverted to a control level in 15 days (Fig. 1). to follow the acinar cells induced into DNA synthesis, 20 hr after a second IPR treatment animals received single injections of methyl‐3H‐thymidine (The Radiochemical Centre, Arnersham, England) (3H‐TdR) by the amount of 20 μCi per 30 g body weight and then were killed at various intervals. Measurements were made on the amount of parotid DNA and its radioactivity in each animal, from which the specific activity of parotid DNA was calculated. the specific activity decreased about seven‐fold to a constant level in 15 days (Fig. 1). the DNA synthesis stimulated by a third and a fourth IPR treatment would account for the decrease in specific activity between day 3 and day 1. an autoradiographic study gave some estimate of cell turnover in the period day 1 to day 10. the IPR‐treated mice were given seventeen injections of 3H‐TdR at 12 hr intervals from 20.00 hours on day 2 to 20.00 hours on day 10 and then
Brief Communication Commercial Pha Preparations Contain Different Mitogenic Components
Authors: Smith C. J. , Allen J. C. 
Published: May 2008

ABSTRACTThree commercially available purified phytohaemagglutinin (PHA) preparations have been examined both chemically and biologically. Marked differences were observed in both composition and mitogenic effect on lymphocytes; the existence of at least two distinct mitogenic fractions in PHA was confirmed.A number of commercial preparations of PHA have become available for use as mitogens in lymphocyte cultures. Since there is no cross‐standardization of biological activity between these preparations, workers have used their own discretion about which to use and whether further purification is desirable.Three commercial purified PHA preparations have been examined, and marked biological and chemical differences have been found.
CELLULAR AND NUCLEAR VOLUME DURING THE CELL CYCLE OF NHIK 3025 CELLS
Authors: Steen H. B. , Lindmo T. 
Published: May 2008

ABSTRACTThe distribution of cellular and nuclear volume in synchronous populations of NHIK 3025 cells, which derive from a cervix carcinoma, have been measured by electronic sizing during the first cell cycle after mitotic selection. Cells given an X‐ray dose of 580 rad in G1, were also studied. During the entire cell cycle the volume distribution of both cells and nuclei is an approximately Gaussian peak with a relative width at half maximum of about 30%. About half of this width is due to imperfect synchrony whereas the rest is associated with various time invariant factors. During S the mean volume of the cells grows exponentially whereas the nuclear volume increases faster than for exponential kinetics. Hence, although cellular and nuclear volumes are closely correlated, their ratio does not remain constant during the cell cycle. Volume growth during the first half of G1 is negligible especially for nuclei where the growth appears to be closely associated with DNA‐synthesis. For unirradiated cells the growth of cellular and nuclear volume is negligible also during G2+ M. In contrast, the X‐irradiated cells continue to grow during the 6 hr mitotic delay with a rate that is constant and about half of that observed in late S. Hence, radiation induced mitotic delay does not appear merely as a lengthening of an otherwise normal G2. During G1 and S the irradiated cells were identical to unirradiated ones with respect to all the parameters measured.