bluuebunny/crossref_metadata_2025_split huggingface dataset:
EXCLUSION OF SERUM FACTORS IN THE IN‐VITRO DEPRESSION OF LYMPHOCYTES’ RESPONSE TO MITOGENS IN CHRONIC LYMPHOCYTIC LEUKAEMIA
Authors: Pentycross Christopher R. 
Published: May 2008

ABSTRACTTo find out whether serum factors are involved in the depression of the mitogenic response of lymphocytes of patients with chronic lymphocytic leukaemia, sera from these patients were used in the culture medium for normal lymphocytes. the results were considered on the basis of the dynamics of responses of these normal lymphocytes, comparing a standard human group AB serum with twenty sera from patients with CLL. No heat‐stable inhibitory factors peculiar to CLL were found. In an experiment in which fresh CLL and normal sera were compared, no heat‐labile inhibitory factors were apparent.
THE SPERMATOGONIAL STEM CELL POPULATION IN ADULT RATS
Authors: Huckins Claire 
Published: May 2008

ABSTRACTRadioautographs of histological sections and whole mounted seminiferous tubules from adult rat testes were used to investigate the kinetic properties of the undifferentiated type A spermatogonial population (1) immediately following multiple injections of 3H‐TdR and (2) at long intervals after single or repeated injections.Most of the undifferentiated type A cells became labeled by five or six successive injections of 3H‐TdR given at 12 hr intervals. Labeling frequency was greater than 90% in stages X‐I, and was maximal in stage I (96‐97%) where only a small proportion (15%) of the isolated undifferentiated spermatogonia (the As stem cells) failed to incorporate the label. Since this unlabeled cohort represented only 1‐3% of the total undifferentiated type A population in stages I‐VII, the existence of a large non‐cycling A0 or reserve stem cell population (which formed 21% of the total A population in stages II‐VII according to Clermont & Bustos‐Obregon, 1968) could not be confirmed. the non‐labeling of a few isolated stem cells was consistent with the previous finding of a prolonged G2 in some of these spermatogonia (Huckins, 1971c). It was therefore concluded that all undifferentiated A spermatogonia, including the As stem cells, were in active cell cycle.Some well‐labeled isolated stem cells persisted for long periods and were still common 13 days (one cycle of the seminiferous epithelium) after 3H‐TdR injection. These appeared to be slow cycling elements which did not divide at all or possibly just once during this interval, but thereafter became mitotically active, giving rise to labeled pairs which in further divisions formed lightly labeled chains of aligned undifferentiated cells. There was a gradual disappearance of the labeled cells, so that by 26 days after 3H‐TdR injection no labeled A spermatogonia remained in the seminiferous epithelium.
MECHANISM OF EOSINOPHILIA
Authors: Spry Christopher J. F. 
Published: May 2008

ABSTRACTThe kinetics of non‐dividing eosinophils was studied in normal rats and rats in which an eosinophilia had been induced by injecting Trichinella spiralis larvae intravenously. the findings suggested that in normal rats eosinophils matured in the spleen after leaving the marrow. the emergence time of eosinophils in normal rats was 41 hr, and was reduced in stimulated rats to 18 hr. Neutrophil emergence time was not reduced, indicating that there are separate mechanisms for regulating the rates of emergence of newly formed eosinophils and neutrophils.The half‐life of eosinophils in the blood of normal rats was 6.7 hr, and was not altered 1.5–3.5 days after larvae were injected, when many eosinophils were accumulating in tissues. the rate of disappearance of labelled eosinophils from the blood was exponential, indicating random loss from the circulation. Eosinophils were mobilized into the pool of circulating eosinophils by a soluble plasma factor (‘eosinophil releasing factor’) which increased the number of circulating eosinophils at 3 and 6 hr. These experiments showed that the number of eosinophils in the blood was regulated by several different mechanisms, which were distinct from those affecting eosinophil production.
DNA SYNTHESIS TIME IN LEUKAEMIC CELLS AS MEASURED BY THE DOUBLE LABELLING AND THE PERCENTAGE LABELLED MITOSES METHODS
Authors: Harriss Eileen B. , Hoelzer D. 
Published: May 2008

ABSTRACTValues of Ts provided by the double labelling method have been compared with those given by the percentage labelled mitoses curve for blast cells in the peripheral blood of a patient with plasma cell leukaemia and of rats bearing a transferable acute leukaemia. the double labelling method was carried out giving the first label (3H‐thymidine) in vivo and the second label (14C‐thymidine) in vitro with several values for the interval between the two labels. Ts was calculated by fitting regression lines to the results obtained. Data for percentage labelled mitoses were analysed by computer. For the plasma cell leukaemia values of Ts= 17.1 ± 7.0 hr and Ts= 19.8 ± 3.4 hr, and for the rat leukaemia values of 8.7 ± 1.7 hr and 9.0 ± 1.7 hr (7.1 hr corrected for exponential growth) were obtained from the percentage labelled mitoses and double labelling methods respectively. It is concluded that the double labelling method is valid for the study of cell proliferation in leukaemic blast cells.
SHORT‐TERM CULTURES OF MOUSE MARROW CELLS SEPARATED BY VELOCITY SEDIMENTATION
Authors: Sutherland D. J. A. , Till J. E. , McCulloch E. A. 
Published: May 2008

ABSTRACTOur experiments were designed to identify the source of the increased number of cells forming colonies in culture (CFU‐C) detected after short‐term culture of mouse marrow cells over ‘feeders’ of renal tubules. Accordingly, marrow cell suspensions were fractionated by velocity sedimentation and aliquots of each fraction cultured for 2 days over tubule ‘feeders’. We found a greater increase of CFU‐C in suspensions of slowly sedimenting cells as compared to rapidly sedimenting cells. Colcemid and vinblastine were used to alter the peak sedimentation velocity of marrow suspensions by changing the distribution of cells in the cell cycle. After such manipulations, the peak increase in CFU‐C continued to be associated with fractions containing slowly sedimenting cells. Such fractions also contained most of the pluripotent stem cells identified by the spleen colony technique.
CONTROL OF GRANULOCYTE PRODUCTION: SEPARATION AND CHEMICAL IDENTIFICATION OF A SPECIFIC INHIBITOR (CHALONE)
Authors: Paukovits W. R. 
Published: May 2008

Abstract. It has previously been shown by others that blood serum contains inhibitors of blood cell production acting on the proliferation of granulocy tic and erythrocytic precursor cells in the bone marrow. It is now shown that the active extract from calf blood serum can be further subfractionated into six different components, all of them exhibiting inhibitory effects on the proliferation of rat bone marrow cells in vitro. Ascitic fluid from rats treated intraperitoneally with polyvinylpyrrolidone contains inhibitors which apparently are the same as those found in calf serum.It was further possible to demonstrate that only one of these inhibitors is contained in mature granulocytes where it is actively synthesized from amino acids and subsequently released into the surrounding medium. By chromatography on Sephadex G‐25 of this conditioned medium the inhibiting substance could be obtained in relatively pure form being contaminated only by low amounts of two ninyhdrin‐positive substances. the experiments allow the granulocytic inhibitor to be identified as a polypeptide with a molecular weight below 5000. the results suggest that this substance is the granulocytic chalone.
Human Lymphocyte Proliferation: Dna Synthesis Time
Authors: Schiffer L. M. 
Published: May 2008

Abstract. The DNA synthesis time (Ts) of lymphocytes from spleens and lymph nodes of patients with Hodgkin's disease was determined by the double labeling method. 3H‐TdR was administered in vivo and removed tissues minced in 14C‐TdR in vitro. Lymphocytes from patients with lymphosarcoma and reticulum cell sarcoma were studied in a similar manner. Lymphocytes were divided into A cells, small with non‐basophilic cytoplasm, B cells, small with basophilic cytoplasm, C cells, large with non‐basophilic cytoplasm, and D cells, large with basophilic cytoplasm.The Ts of splenic lymphocytes, in four samples not containing Reed‐Sternberg cells, in hours, was: B 11.3; C, 7.9; D, 8.4; combined, 8.8. the Ts of B lymphocytes was significantly longer than that of C and D lymphocytes. A lymphocytes did not label sufficiently to measure Ts. C and D lymph node lymphocytes and lymphocytes in tissues containing Reed‐Sternberg cells had a longer Ts than splenic C and D cells. the former was: B, 12.7; C, 11.7; D, 11.0; combined, 11.8. the latter was: B, 12.2; C, 11.3; D, 11.2; combined, 11.6. the Ts of Reed‐Sternberg cells in one specimen of a splenic Hodgkin's tumor was 13.1 hr. Macrophage Ts was 10.7 and 15.1 hr. Lymphosarcoma cell Ts was 14.2 and 14.6 hr. Reticulum cell sarcoma cell Ts was 7.5 and 7.7 hr.The following minimum times were calculated from observation of 3H‐TdR only labeled mitotic figures: S to prophase, 71 min; S to metaphase, 75 min; S to telophase, 100 min.
LOCATION OF THE G0‐PHASE IN THE CELL CYCLE OF THE MOUSE HAEMOPOIETIC SPLEEN COLONY FORMING CELLS
Authors: Lahiri S. K. , Van Putten L. M. 
Published: May 2008

Experiments in mice on the fraction of haemopoietic stem cells in S‐phase after irradiation indicated that a large fraction of the cells resting in G0 will enter S‐phase after a very short interval of time.After excluding alternative explanations it must be concluded that cells in G0 have completed all preparations for going into S‐phase or, in other words, that the localization of these G0 cells in relation to other phases of the cell cycle must be between G1 and S‐phase.
CELL DIFFERENTIATION AND CARCINOGENESIS: A CRITICAL REVIEW*
Authors: Dustin P. 
Published: May 2008

Many resemblances exist between cell differentiation and neoplastic change: the importance of cytoplasmic factors is particularly evident, as the genotype appears to remain unmodified in the nuclei of differentiated as in malignant cells.There is no opposition between malignancy and differentiation, highly malignant cells retaining in many cases a differentiation very close to normal. Loss of differentiation in malignancy is only an epiphenomenon.While differentiation appears to be partially reversible, and in some models totally reversible, neoplastic changes are, with a very small number of exceptions, irreversible. Differentiation involves the gradual change of a group or a population of cells, malignancy of a single cell.Further work on the molecular basis of differentiation would help to understand the nature of neoplasia, and vice versa.
DNA TURNOVER IN ADRENAL MEDULLARY CELLS OF DIFFERENT STRAINS OF RATS AND ITS ENHANCEMENT AFTER INTERMITTENT EXPOSURE TO COLD
Authors: Malvaldi G. , Viola‐Magni Maria Pia 
Published: May 2008

In Italico and Wistar rats maintained at room temperature 1% of nuclei of cells in the adrenal medulla incorporate 3H‐thymidine. Following intermittent exposure to cold, the numbers incorporating increase to 10% and 7% in Italico and Wistar strains respectively. Only in the Wistar strain does the increase occur during actual exposure.Assuming S to be 6–8 hr the labelling indices actually determined indicate a turnover time of DNA of 21–29 days. Since mitotic indices in experimental and control animals were found to be 0.004% without colchicine treatment and 0.009% after 3 hr of colchicine treatment, the turnover times of cells were calculated to be 1388–3125 days. To correlate mitotic indices and labelling indices, an S period of 400 hr would have to be assumed. It is concluded therefore that: (i) most of the observed labelling of DNA is due to metabolic turnover of DNA and only a small proportion represents pre‐mitotic synthesis, (ii) differences in the rates of DNA synthesis found during exposure to cold in Italico and Wistar rats respectively are sufficient to account for the differences in reduction of DNA previously found between the two strains under these experimental conditions.
AUTORADIOGRAPHIC DETECTION OF DNA POLYMERASE CONTAINING NUCLEI IN SARCOMA 180 ASCITES CELLS
Authors: Nelson Janet S. R. , Schiffer Lewis M. 
Published: May 2008

ABSTRACTA technique has been developed allowing the autoradiographic detection of incorporation of 3H‐thymidine‐5′‐triphosphate (3H‐TTP) into nuclear DNA of smears of Sarcoma‐180 (S‐180) mouse ascites tumors under the direction of the cell's own nuclear DNA polymerase. Dried smears are dipped into an agar solution, which strips cytoplasm from the nuclei, and are then air dried and incubated with a buffered mixture containing four nucleotide triphosphates (one labeled), Mg++, and Ficoll, with the cell's own DNA acting as primer. The incorporation of 3H‐TTP into the nuclei, like the cell free DNA polymerase assay, is largely dependent on the presence of all four nucleotide triphosphates and Mg++ and produces a product which is DNase sensitive and RNase resistant.DNA polymerase activity, as studied in a cell free assay, decreases with tumor age. This correlates well with a decreasing 3H‐TTP labeling index in autoradiographs of aging tumors. The 3H‐TTP labeling index has also been shown to exceed but parallel the in vivo3H‐thymidine (3H‐TdR) pulse labeling index for all tumor ages examined.In at least some cell systems DNA polymerase seems characteristic of cells in cycle. The autoradiographic detection of nuclei containing the enzyme offers a new tool for the study of tumor cytokinetics.
THE CELL SPECIFIC EFFECT OF THE GRANULOCYTE CHALONE DEMONSTRATED WITH THE DIFFUSION CHAMBER TECHNIQUE
Authors: Benestad H. B. , Rytömaa T. , Kiviniemi Kyllikki 
Published: May 2008

ABSTRACTThe granulocytic chalone is secreted by mature granulocytes and inhibits 3H‐thymidine incorporation of proliferating granulocytes in vitro. The effect and the cell line specificity of this chalone was assessed with the in vivo diffusion chamber culture technique. Tests were carried out on cultures from normal mouse bone marrow cells and mouse and rat blood leucocytes. The majority of the DNA synthesizing cells in marrow cultures were proliferating granulocytes. Macrophages and immunoblasts proliferated in rat leucocyte cultures, when the chambers had been carried for 5 days in host mice. Repeated chalone or control injections were given i.p. to the host mice during 6–7 hr prior to 3H‐thymidine injection. Isotope uptake of proliferative granulocytes was reduced by the chalone treatment. No such effect was found on the rat immunoblasts and macrophages. The viability of cultured cells was apparently not affected by the chalone treatment.
CELL PROLIFERATION IN THE CASTRATE MOUSE SEMINAL VESICLE IN RESPONSE TO TESTOSTERONE PROPIONATE
Authors: Appleton David , Morley Adrian R. , Wright Nicholas A. 
Published: May 2008

ABSTRACTThe cell cycle kinetics of a conditional renewal system which has been stimulated by a continuing supply of hormone were investigated by means of a model, basic to which is the concept of decycling probability. The integral equations of the system were formulated and solved numerically in an environment of interaction with the computer. Graphical output on a visual display screen was used to facilitate the extraction of information from the model, and its consistency with experimental data was demonstrated.
CYTOLOGICAL CHARACTERISTICS OF NORMAL HUMAN PERIPHERAL BLOOD CELLS IN CULTURE BEFORE ESTABLISHMENT INTO LYMPHOCYTOID CELL LINES*
Authors: v. Heyden H. W. , Heyden Dorit v. 
Published: May 2008

ABSTRACTHuman peripheral blood cells were observed in culture. Attached cells and those floating in the supernatant fluid were classified as macrophages, lymphoid and fibroblastoid cells. Peroxidase positive granules were demonstrated in macrophages and fibroblastoid cells. It is concluded that (a) appearance of macrophages is dependent on the formation of a monolayer, (b) a gradient relationship between the attached and supernatant cells exists, (c) some fibroblastoid cells are derived from macrophages, and (d) lymphocytes alone are not able to form a monolayer.
SPERMATOGONIAL STEM CELL RENEWAL IN THE MOUSE: II AFTER CELL LOSS
Authors: van Keulen C. J. G. , de Rooij D. G. 
Published: May 2008

ABSTRACTThe repair of the mouse seminiferous epithelium after cell loss has been studied in seminiferous tubules mounted in toto. Cell loss was inflicted by injection of Myleran in a dose of 10 mg/kg body weight. In stages 7–8, in which we mainly counted, the numbers of Aisolated (Ais), Apaired (Apr), Aaligned (Aal) and A1 spermatogonia and resting primary spermatocytes decreased after injection. After about 24 days normal numbers of A1 spermatogonia were found again. Thereafter a substantial overshoot in the number of A1 spermatogonia was found.While normally most of the Apr and Aal cells differentiate into A1 spermatogonia in stages 3 and 4 and do not divide until stage 9, during repair they pass through one more division during stages 6 and 7. Normally, during these stages divisions of these spermatogonia are rare. Owing to this extra division the transformation of Apr and Aal into A1 spermatogonia is delayed from stage 3 or 4 to stage 8, i.e. still before stage 9, in which A1 spermatogonia divide. From 16 days after the injection onwards the extra division takes place less generally and more and more cells transform into A1 spermatogonia at the normal time.
ON THE RESTING STAGES OF THE JB‐1 ASCITES TUMOUR
Authors: Bichel P. , Dombernowsky P. 
Published: May 2008

ABSTRACTCytophotometric determination of single‐cell DNA after repeated 3H‐thymidine labelling of the JB‐1 ascites tumour in the plateau phase of growth showed a massive accumulation of unlabelled cells with both G1 and G2 content. Autoradiography combined with cytophotometry or colcemid block demonstrated that some of these unlabelled cells were rapidly triggered into the cell cycle when plateau tumours were transferred to new hosts. This indicated that tumour cells may be held up in non‐cycling stages corresponding to both the G1 and the G2 phase of the cell cycle.
KINETICS OF NEUTROPHILIC GRANULOCYTES IN THE BLOOD OF RATS
Authors: Gerecke D. , Schultze B. , Maurer W. 
Published: May 2008

ABSTRACTThe kinetics of neutrophilic granulocytes in the blood of rats were investigated using in vivo3H‐TdR labelling and autoradiography. The radioactive precursor was administered by single injection, repeated injections at 5 hr intervals and continuous infusion. The appearance of labelled granulocytes in the blood and in the sputum was recorded up to 120 hr after tracer application. In contrast to results after a single injection of 3H‐TdR, complete labelling of the blood granulocyte pool was achieved when the DNA precursor was given by continuous infusion or four repeated injections at 5 hr intervals. In the latter experiments, an exponential replacement of unlabelled blood granulocytes by labelled granulocytes could be demonstrated, the mean intravascular half‐life being 5·7 hr. This figure is in good agreement with values obtained by isotopic techniques in other mammalian species.
COMPUTER OPTIMIZATION OF THE FRACTION OF LABELLED MITOSES ANALYSIS USING THE FAST FOURIER TRANSFORM
Authors: Ashihara Tsukasa 
Published: May 2008

ABSTRACTThis paper provides a numerical technique for the solution of the fraction of labelled mitoses curve. The essence of the method is to facilitate convolutions of phase time distributions using the FFT. This FFT method, in conjunction with the optimization technique, is found to be an efficient, general procedure.
RESPONSE OF MOUSE BONE MARROW COLONY FORMING UNITS IN DIFFERENT STAGES OF THE CELL CYCLE TO IN VITRO INCUBATION WITH MITOMYCIN‐C
Authors: Lahiri S. K. 
Published: May 2008

ABSTRACTA short‐term in vitro method was employed to study the Mitomycin‐C sensitivity of normal mouse bone marrow CFU without triggering the G0‐phase cells into the proliferative cycle. Comparison was made of the toxicities of the drug against cells in different phases of the cell cycle including G0. Mitomycin‐c killed CFU both in and out of the S‐phase. No significant difference could be found between its toxicities against normal and proliferating CFU; along the exponential part of the survival curve 1·6 μg/ml concentration of the drug reduced survival to 10%. Although in the normal bone marrow only a few CFU are in the S‐phase and are killed by the agent, presence of the sensitive G0 cells produce a significant amount of non‐S‐phase mortality. Among the proliferating CFU population the non‐S‐phase lethality is less due to the absence of G0 cells. About 75% of the S‐phase cells are killed after incubation with 1 μg/ml drug; outside the S‐phase, the lethality is about 40–50%. The studies indicate that the G0 cells which are situated near the G1‐S boundary are almost as sensitive to the drug as other non‐S‐phase cells like G1 cells. The clinical significance of the findings is discussed.
DOUBLE PULSE LABELLING WITH 3H‐THYMIDINE: A METHOD FOR CALCULATING CELL POPULATIO KINETICS
Authors: Sharav Y. , Brin‐Erb I. , Sciaky I. 
Published: May 2008

ABSTRACTA method was developed for calculating cell population kinetics with the aid of double pulse labelling with 3H‐TdR. The labelling index was measured from auto‐radiographs of the oral epithelium of two groups of 30‐day‐old rats. One group was injected once with 3H‐TdR the other twice, with a time interval of 90 min between injections. DNA synthesis time was calculated from the equation:where Ts= synthesis time; LI1= labelling index in the single‐injected group; LI2= labelling index in the double‐injected group; and Ti= time interval between injections. Synthesis time in the palate was 4.8 hr and 7.6 hr in the tongue. Generation time was calculated from the equation: Tg= (Ts/LI1) × 100, where Tg= generation time. Generation time in the palate was 46.1 hr and 75.8 hr in the tongue
PERIODIC THERMAL STRESS: OPTIMAL SPACING PREDICTED BY A SIMPLE SET‐BACK MODEL OF CELL DIVISION SYNCHRONIZATION
Authors: Rooney David W. , Kovac Anthony L. 
Published: May 2008

ABSTRACTDigital computer simulations have been used to make quantitative predictions based on a simple set‐back model of cell division synchronization. According to the model appropriate thermal stress reverses progress within a segment of the division cycle called the set‐back interval. In the simulations normally distributed cell‐to‐cell variations in division cycling rate between periodic thermal shocks were produced with the Monte Carlo method.The simulations have shown that reasonably good synchronization with the single shock per division strategy requires a relatively long set‐back interval and small cell‐to‐cell variations in rate of progress through the division cycle. The simulations have shown that the degree of synchrony produced by such periodic shocks is highly dependent on the time interval between shocks—with a series of as many as seven shocks inappropriately spaced producing less synchrony than a single shock! The optimal time interval between successive thermal shocks was found approximately equal to the mode division cycle time at synchrony equilibrium multiplied by 1 plus half the fraction of the division cycle occupied by the set‐back interval. Position of the set‐back interval within the division cycle had little effect on synchrony at the end of the final shock.