bluuebunny/crossref_metadata_2025_split huggingface dataset:
AN AUTORADIOGRAPHIC AND MORPHOLOGICAL STUDY OF MOUSE BONE MARROW LITTORAL CELLS DURING AND AFTER TREATMENT WITH URETHANE
Authors: Langdon HerbertL. , Berman Irwin 
Published: May 2008

AbstractThis study demonstrates that the labeling index of mouse marrow littoral cells can be markedly altered as a result of treatment with ethyl carbamate (urethane). Young C57/BL mice were given daily intraperitoneal urethane injections for periods up to 6 days. Following treatment each day, as well as daily over a 10 day recovery period, a group of animals was administered tritiated thymidine every 3 hr over a 24 hr period and sacrificed ½ hr after the last injection. Marrow was embedded in epon and 0·5 μm sections cut for autoradiographic and light microscopic analysis. A thirty‐five‐fold increase in the percentage labeled littoral cells was observed after three injections of urethane. The labeling index of littoral cells fluctuated during the treatment period and during the 10 day recovery period. The labeling data are discussed in relation to the possible effects of urethane on the cell cycle of mouse marrow littoral cells; the morphological sequela to urethane treatment and the nossibilitv that littoral cells mav act as stem cells.
POLYMETHACRYLIC ACID: INDUCTION OF LYMPHOCYTOSIS AND TISSUE DISTRIBUTION
Authors: Ross W. M. , Martens A. C. , Bekkum D. W. van 
Published: May 2008

AbstractPolymethacrylic acid (PMAA) induces up to a three‐fold increase in the lymphocyte population of peripheral blood in rats, goats and calves after intravenous administration. Other routes of administration are less effective. A maximum lymphocytosis is achieved after 3 hr with all doses in excess of 30 mg PMAA/kg body weight; over the next few hours the lymphocyte level declines to normal. Granulocytes increase steadily for the first 7 hr before declining. Multiple doses of PMAA 2 hr apart failed to maintain or significantly alter the lymphocytosis.PMAA was labelled with 125I and 14C, and was traced to various sites in the rat. The greatest accumulation of radioactivity was in the spleen, lungs, liver, kidney, adrenals and mesenteric lymph nodes (with 14C‐PMAA). The accumulation appeared more specific for spleen and lymph nodes since there was only a small loss of activity following removal of blood by whole body perfusion. This supports previous findings indicating that these two tissues play a major role in the development of lymphocytosis. Accumulation in the bone marrow may be indicative of stem cell mobilization.The results are discussed in terms of the lymphocytosis‐inducing mechanism and the site of action of PMAA and the possible clinical application to ECIB therapy is considered.
STUDIES ON THE REGULATION OF LYMPHOCYTE PRODUCTION IN THE MURINE THYMUS AND SOME EFFECTS OF A CRUDE THYMUS EXTRACT
Authors: Olsson Lennart , Claësson Mogens H. 
Published: May 2008

AbstractCell proliferation in the murine thymus was studied in vivo under normal conditions and from 0 to 24 hr after a single injection of a water‐soluble extract from mouse thymus, mouse spleen, and mouse skin. The thymus extract reduced during the first 24 hr the mitotic activity 40%; the spleen extract had a weaker inhibitory effect. The skin extract had no such effect. The thymus extract and spleen extract inhibited the flux of cells into the S phase 0–8 hr after the injection of the extract. Initial labelling index was also reduced in this period. Eight hours after injection of the thymus or spleen extracts the inhibited cells initiated DNA synthesis. The rate of progression of blast cells through the cell cycle was normal 24 hr after the injection of the extracts.It was deduced from the analysis that the thymus extract inhibits processes triggering Go/Gi cells into DNA synthesis, the inhibition of G2 efflux being of minor importance. Finally a model for the regulation of proliferating thymic blast cells and the emigration of small lymphocytes from the thymus is proposed.
SPERMATOGENETIC CLONES DEVELOPING FROM REPOPULATING STEM CELLS SURVIVING A HIGH DOSE OF AN ALKYLATING AGENT
Authors: Keulen C. J. G. van , Rooij D. G. de 
Published: May 2008

AbstractWe investigated stem cell renewal and differentiation in 10‐ and 15‐days‐old spermatogonial clones developing in mouse seminiferous epithelium after an extremely large cell loss, inflicted by high doses of the alkylating agent Myleran.The spermatogonial clones arise from cells that resemble the Ais spermatogonia but have a larger nuclear diameter. In spite of their mitotic activity these ‘re‐populating stem cells’ lie mainly isolated or in pairs. This is explained by migration and differentiation. Migration appeared to occur at random in all directions along the basement membrane of the seminiferous tubule.After one or more divisions of the stem cells, a second type of cell appears, which is called the ‘differentiating spermatogonium’. The time elapsing before this type of cell appears, depends on the dose of Myleran: the larger the dose the later differentiation starts. A relation could be demonstrated between the stage of the cycle of the seminiferous epithelium and the start of differentiation. Differentiating cells were found isolated or in groups of two, four, eight or sixteen cells. Hence we concluded that at least up to their fourth division differentiating cells divide synchronously without degenerations.Three types of division of repopulating stem cells were distinguished, producing (1) two repopulating stem cells, (2) one repopulating stem cell and one cell starting spermatogonial differentiation, or (3) two differentiating cells. Type 1 divisions were found most frequently.
THE INFLUENCE OF A GRANULOCYTIC INHIBITOR(S) ON HEMATOPOIESIS IN AN IN VIVO CULTURE SYSTEM
Authors: MacVittie Thomas J. , McCarthy Kenneth F. 
Published: May 2008

AbstractThe in vivo diffusion chamber (DC) technique for mouse marrow culture was used to determine the effect of a granulocyte inhibitor on the proliferation of the pluri‐potent stem cell (CFU‐s) and the granulocyte progenitor cell (CFU‐c). Granulocyte conditioned medium was injected intraperitoneally into mice bearing DCs during the initial 48 hr of culture. The early injection of inhibitor resulted in a significantly reduced number of granulocytic progeny formed within the DCs while there was no growth inhibition of mouse fibroblasts cultured under identical conditions. The reduced cell production was due in part to a significant reduction in the self‐renewal rate of the CFU‐c while no apparent direct effect was observed upon the growth of the CFU‐s within the same cultures.These data suggest that the granulocytic inhibitor(s) acted to reduce proliferation within the CFU‐c population and thereby diminished the amplification potential inherent in the initial cell inoculum.
INHIBITORY AND ANTI‐INHIBITORY FACTORS OF RAT SERUM ACTIVE ON THE G1‐S TRANSITION OF HEPATOCYTE CELL CYCLE
Authors: Nadal C. , Boffa G. A. 
Published: May 2008

ABSTRACTRat hepatocytes are responsive to a serum factor inhibiting their progression through the cell cycle from the late G1 phase to the S phase. After fractionation of normal adult rat serum by two chromatographic steps on DEAE cellulose and sephadex gel filtration, the inhibitory activity was linked to proteins having a high electronegative charge and of apparent high molecular weight. Polyacrylamide gel electrophoretic analysis of active fraction showed that the α1 macroglobulin was its main component. Male and female baby rats were sensitive to the inhibitory factor from normal rats.Contrary to the normal adult rat serum the whole hepatectomized adult rat serum did not exhibit any inhibitory activity on the G1‐S transition. However, two components having antagonist activities: an α1 globulin and a γ globulin, were separated by chromatographic procedures from hepatectomized rat serum.

The α1 globulin showed an inhibitory activity. It had an apparent molecular weight lower than that found in normal rats. Its activity was sex related: only male baby rats were responsive.
The factor present in the γ globulin fraction was found to be antagonistic to the α1 globulin factor. Its occurrence after hepatectomy explains the absence of inhibitory activity in the serum of hepatectomized rats.
METALLIC COPPER‐INDUCED GRANULOCYTE EXUDATION IN THE STUDY OF GRANULOCYTOPOIESIS
Authors: McGarry Michael P. 
Published: May 2008

ABSTRACTC3H/HeHa mice implanted with rods of metallic copper (CR) or glass (GR) exudate neutrophil granulocytes and mononuclear cells into the site of rod implant (peritoneal cavity). Exudation in CR mice is substantially greater than in GR animals. In CR mice there is an impressive stimulation of myelopoiesis measured in the femoral marrow subsequent to the initial accumulation in the peritoneal cavity. Serum levels of colony stimulating activity (CSA), an in vitro myeloproliferative stimulating activity, are elevated in such animals, as are femoral marrow agar‐colony forming cells (CFC). The procedure is useful to the study of myelopoiesis and myelopoietic regulatory mechanisms.
CELL POPULATION KINETICS IN THE RAT JEJUNAL CRYPT
Authors: Wright Nicholas A. , Al‐dewachi Huthaifa S. , APPLETON David R. , Watson Alexander J. 
Published: May 2008

ABSTRACTCell kinetics in the jejunal crypt of the male Wistar rat were studied using autoradiographic techniques with tritiated thymidine and a stathmokinetic technique with vincristine. The migration rate measured by following the movement of the 50 % peak on the labelling index distribution curve with time after injection of tritiated thymidine gave a value of 1.43 ± 0.14 (SE) cell positions per hour, compared with a value from a cumulative birth rate of 1.78 cell positions per hour.The crypt column length was 32.9 ± 0.2 cells and the column count was 22.3 ± 0.2. This measurement gave a total crypt population of 734 cells, compared with an estimate of 650 ± 6 from direct observation of squashed, microdissected crypts. In each crypt 22.5 ± 0.5 mitoses were present, and the crypt cell production rate was 32 cells per crypt per hour; this latter value was confirmed using two independent techniques.The crypt growth fraction calculated from the durations of phases of the cell cycle and the labelling index was 0.62. A value of 0.61 was found from the labelling index distribution curve. As assessed from crypt squashes, there were 403 proliferating cells per crypt.
CELL KINETICS OF IRRADIATED EXPERIMENTAL TUMORS: RELATIONSHIP BETWEEN THE PROLIFERATING AND THE NONPROLIFERATING POOL
Authors: Potmesil Milan , Ludwig Donald , Goldfeder Anna 
Published: May 2008

ABSTRACTThe role of nonproliferating cells in tumor regeneration has been studied after subcurative doses of low L.E.T. irradiation. Radiation was applied in a single dose at three different levels, 0–47, 0–94 and 1–88 krad. Studies included estimation of the absolute number of cells per tumor, differential cell counts, and autoradiographic determination of kinetic variables, employing transplantable mouse mammary adenocarcinoma DBAH.Quantitative changes of morphologically denned proliferating and non‐proliferating cell pools were followed at different time intervals after irradiation. Irradiation resulted in reduction of the number of cells in both pools, with apparent sparing of nonproliferating cells. The regenerative period started with a gradual increase in the number of cells in the proliferating pool, whereas the number of cells in the nonproliferating pool continued to fall in tumors irradiated with 0–94 and 1 ‐88 krad. In the late phase of tumor regrowth, the increasing number of cells in the non proliferating pool corresponded to its replenishment by cell transition from the proliferating pool.In an effort to clarify whether cell transition from the nonproliferating to the proliferating pool may take place during the regrowth of radiation perturbed tumors, cell loss rates from both pools were estimated using experimental data. In addition to cell losses from the tumor as a whole, the ‘net loss rate’ of the non‐proliferating pool reflects the rate of cell transition from the nonproliferating to the proliferating pool, minus the rate of transition in the opposite direction. A similar definition applies to cell loss rates from the proliferating pool. The results showed: (1) high losses in both pools, with excess losses in the proliferating during the early phase after irradiation; (2) in the early stage of regrowth after irradiation, the cell net loss rate for the nonproliferating pool increased, in contrast to the behavior of cell loss rate for the proliferating pool and the average cell loss rate for the tumor as a whole; (3) in the late stage of regrowth a decrease in net loss rate for the nonproliferating pool reflects the excess production of nonproliferating cells over control tumors. These results suggest that cell transition from the nonproliferating to the proliferating pool takes place at the beginning of tumor regrowth after subcurative single‐dose irradiation.
THE INFLUENCE OF 400 R X‐IRRADIATION ON THE NUMBER and THE OCALIZATION OF MATURE and IMMATURE GOBLET CELLS and PANETH CELLS IN INTESTINAL CRYPT and VILLUS
Authors: Dongen J. M. VAN , Kooyman J. , Visser W. J. 
Published: May 2008

AbstractThe influence of 400 R X‐irradiation on the localization and the number of mature and immature goblet cells and Paneth cells in rat duodenal epithelium has been studied. At short times after irradiation, when the total proliferative activity in the crypts of Lieberkiihn is reduced, the proportion of mature and immature goblet cells of the total number of crypt cells was increased; also an absolute increase in the number of goblet cells in the crypts was found. The immature goblet cells were localized in the lower half of the crypt as in control animals, whereas the number of the mature cells increased over the whole crypt length. When the proliferative activity of the crypt cells increases again from 12 to 48 hr after irradiation the number of both types of goblet cells decreases. Between 48 and 72 hr, when the whole crypt is involved in proliferation, a second increase of both types of goblet cells was found. However, the localization of the immature goblet cells is no longer restricted to the lower half of the crypt but they also appear at the higher cell positions.On the villus no immature goblet cells were found and the changes in the numbers of mature goblet cells do reflect the changes induced by irradiation in the goblet cell population in the crypt. The absolute number and localization of Paneth cells did not change under the experimental conditions. The findings are discussed in relation to cell proliferation and differentiation processes in intestinal crypts.
EFFECT OF A SPERMATOGONIAL CHALONE ON THE GROWING RAT TESTIS
Authors: Clermont Y. , Mauger A. 
Published: May 2008

AbstractImmature rats were used in an experiment to test the possible influence of a spermatogonial chalone on the expanding spermatogonial population in their developing testes. An extract from adult rat testes was injected intraperitoneally into 33‐day‐old rats and control animals were injected with an equal amount of saline. Two groups of normal adult rats similarly injected with the testicular extract and saline solutions served as additional controls. Following these injections, all animals were administered a dose of 3H‐thymidine 10 hr before sacrifice. An analysis of the labeling indices of the various types of spermatogonia revealed that in young rats injected with testicular extract the percentage of labeled type A spermatogonia was significantly lower than in control animals. In contrast, the labeling indices of Intermediate and type B spermatogonia were similar in the two groups of young rats. In the two groups of adult animals, there was no difference in the labeling indices of type A or of other types of spermatogonia. These data indicated that the saline extract of adult testes contained a substance, a spermatogonial chalone, inhibiting specifically the proliferation of some type A spermatogonia. The results also support the concept that a spermatogonial chalone may intervene, through its action on the spermatogonial stem cell population, to arrest the growth of the seminiferous tubules as the animal reaches maturity.
THE PREDOMINANT ROLE OF THE SPLEEN IN LYMPHOCYTE RECIRCULATION
Authors: Pabst R. , Trepel F. 
Published: May 2008

AbstractAutologous blood lymphocytes from three normal pigs were labelled with 3H‐uridine and retransfused before and after splenectomy. Frequent samples for up to 150 min after retransfusion were evaluated autoradiographically to determine the rate of disappearance of labelled lymphocytes from the blood. In one pig retransfusion was performed before and after sham‐splenectomy.In all preoperative experiments the pattern of disappearance of labelled lymphocytes was very similar. After a first rapid decline (halving time on average 8 min) a short rise of the labelling index was observed from 10 to 15 min after retransfusion. Then a second more gradual decrease of labelled lymphocytes followed. The mean halving time during this period was less than 32 min. From 60 min onwards the labelling index remained nearly constant. Retransfusions performed 3 days after splenectomy revealed only one nearly constant decline of the labelling index (halving time on average 129 min). After sham‐splenectomy the pattern of disappearance was similar to the preoperative experiment. One hour after the end of retransfusion the labelling index had decreased by three‐quarters of the initial value in normal pigs and by only one‐third in the splenectomized ones. These results indicate that in the pig the total rate of recirculation is at least 4 times faster with the spleen in situ than without the spleen.
CELL PROLIFERATION IN THE ERYTHROID COMPARTMENT OF GUINEA‐PIG BONE MARROW: STUDIES WITH 3H‐THYMIDINE
Authors: Starling Mark R. , Rosse Cornelius 
Published: May 2008

AbstractSingle and multiple injections of 3H‐TdR have been used for measuring the rate of proliferation in morphologically defined cell populations of guinea‐pig bone marrow that are committed to erythroid differentiation. The conclusions are based on the analysis of absolute cell numbers in the maturational compartments, the labeling and mitotic indices, labeled mitotic curves, pulse and chase grain counts over dividing and interphase cells, and on the rate of labeling during multiple, repeated injections of 3H‐TdR. The average duration of S and the rate of cycling is similar in all maturational compartments of the erythron. The majority of cells progress to the next maturational compartment by the time they divide for the second time. All proerythroblasts and basophilic erythroblasts are in cycle. Polychromatic erythroblasts incapable of incorporating 3H‐TdR reach the orthochromatic population in the span of 5–6 hr. The orthochromatic population is renewed every 20–24 hr. The number of divisions between the proerythroblast and orthochromatic erythroblast does not exceed four and some cells may undergo only two divisions during the maturation pathway. Cell input from a progenitor cell population contributes to the maintenance of the erythron. The kinetic behavior of progenitor cells is similar to that of proerythroblasts. By the time of their second division, progenitor cells may reach either the proerythroblast or basophilic erythroblast compartments. The kinetic behavior of basophilic transitional cells corresponds to the predicted behavior of the erythroblast progenitor cell pool. Several of the conclusions are based on the assumption that grain count halving is the result of cell division. In view of the evidence discussed, this assumption in the present studies seems justified.
STUDY OF THE EFFECT OF HYDROXYUREA ON THE ERYTHROPOIETIN‐SENSITIVE CELLS
Authors: Nećs E. , Neuwirt J. 
Published: May 2008

AbstractThe response of polycythaemic mice to a standard dose of erythropoietin has been measured at various, time intervals after single or repeated injections of hydroxyurea. The results exclude S phase of the cell cycle as the period responsive to erythropoietin. They suggest the existence of feedback mechanisms within the cell cycle, operating at the G1‐S boundary and within the G1 phase.Hydroxyurea given to polycythaemic mice at various time intervals after erythropoietin induced characteristic changes in the response. These changes can be explained if both gradual transit of differentiated cells into the DNA synthesis (S phase) and changes in amount of the erythropoietin sensitive cells caused by the feedback mechanisms operating in the cell cycle are considered.
CYTODYNAMICS IN THE THYMUS OF YOUNG ADULT MICE:
Authors: Cläesson Mogens Helweg , Hartmann Niels Rudolph 
Published: May 2008

AbstractCell proliferation and cell loss in the thymic blast cell population were studied in young adult mice by (1) stathmokinetic methods combined with an analysis of the PLMe‐curve after a pulse 3H‐TdR, and (2) nigrosin‐dye exclusion combined with 3H‐TdR‐autoradiography. It was calculated that about 17% of the blast cells do not progress into mitosis within the period of an average cell cycle. The dye exclusion studies indicated a rate of blast cell death of about 2–5 %/hr. The two methods of assessing blast cell loss (death) support each other very well. In spite of these findings scintillation countings on thymuses removed from 1 to 17 hr after 3H‐TdR injection showed fairly constant levels of thymic radioactivity. This suggests a very extensive reutilization of 3H‐labelled break‐down products from dying blast cells. The very sparse labelling of pyknotic thymocytes strongly suggests that thymic blast cells do not become pyknotic. The rate of small thymocyte production and disappearance was studied by pulse and repeated 3H‐TdR labelling techniques combined with dye exclusion studies and pyknotic counts. The data from the repeated labelling experiment were analysed by use of a model based on the assumption of first order kinetics of small viable, dead, and pyknotic thymocytes. The rate of cell production was estimated to 1–6 %/hr whereas the rates of cell loss due to disintegration, i.e. supravital stainability and nuclear pyknosis, were calculated to 0–02 %/hr and 0–0006 %/hr respectively. Cell loss due to disintegration was less than 2 % of the total loss of small thymocytes. It was concluded that pyknotic counts are a useless method of assessing the cell death in the population of thymic blast cells and small thymocytes. On the basis of a model for thymocyte proliferation, production and loss it is suggested that about 45 % of the small viable thymocytes re‐enter the generative cell pool, whereas about 55% disappear by emigration.
PERIODONTAL LIGAMENT CELL KINETICS FOLLOWING ORTHODONTIC TOOTH MOVEMENT
Authors: Yee J. A. , Kimmel D. B. , Jee W. S. S. 
Published: May 2008

AbstractThe population of periodontal ligament (PDL) fibroblasts examined in this study may include osteogenic progenitor cells. PDL fibroblast and osteoblast kinetics in the periodontal ligament of the rat were measured following orthodontic stimulation of bone formation. Both single and multiple injections of tritiated thymidine (3H‐TdR) were used. In single injection experiments, the peak percentage of PDL fibroblasts labeled with 3H‐TdR is 15% at 22 hr post‐stimulation. In multiple injection experiments, the total percentage of fibroblasts in the PDL which respond by synthesizing DNA is 50%. 3H‐TdR‐Iabeled osteoblasts appear at the same rate as, but with a time delay after, the labeled fibroblasts. Following stimulation, the most likely source of osteoblasts at the bone‐forming site is not only fibroblasts which make DNA, divide, then differentiate, but also fibroblasts which either are differentiated to osteoblasts without DNA synthesis and cell division, or are released from G2 block by the orthodontic stimulation.