scholarly journals EVIDENCE FOR AN ESSENTIALLY CONSTANT DURATION OF DNA SYNTHESIS IN RENEWING EPITHELIA OF THE ADULT MOUSE

1963 ◽  
Vol 18 (1) ◽  
pp. 31-40 ◽  
Author(s):  
Ivan L. Cameron ◽  
Richard C. Greulich
Keyword(s):  
Dna Synthesis ◽  
Mammalian Cells ◽  
Adult Mouse ◽  
Tritiated Thymidine ◽  
Constant Duration ◽  
The Times ◽  
Time Required ◽  
Relationship Of

Tritiated thymidine autoradiography has been applied to several renewing epithelial tissues of the adult mouse in order to determine (a) the average time required for DNA synthesis; and (b) the temporal relationship of the synthesis period to the progenitor cycles of these populations. The average duration of DNA synthesis has been computed from curves describing the rates of appearance and disappearance of labeled metaphase figures in epithelia of colon, ileum, duodenum, esophagus, and oral cavity, in both normal and colchicine-treated animals. In general, application of colchicine does not significantly influence the derived values for DNA synthesis duration. The DNA synthetic time is remarkably similar in the tissues examined, despite wide differences in the times required for completion of the progenitor cycle (and for tissue renewal). Synthesis of DNA in these epithelial cells of the mouse requires approximately 7 hours. Agreement between this value and those derived by other investigators for mammalian cells in vivo and in vitro indicates that DNA synthetic time may be a temporal constant, of considerable potential utility to studies of cell proliferation. The advantages and shortcomings of this experimental approach to problems of cell population kinetics in vivo are discussed.

scholarly journals Deoxyribonucleic acid synthesis in mammalian nuclei. Incorporation of deoxyribonucleotides and chain-terminating nucleotide analogues

1971 ◽  
Vol 121 (5) ◽  
pp. 803-809 ◽  
Author(s):  
M. A. Waqar ◽  
L. A. Burgoyne ◽  
M. R. Atkinson
Keyword(s):  
Dna Synthesis ◽  
Deoxyribonucleic Acid ◽  
Acid Synthesis ◽  
Deoxyribonucleic Acid Synthesis ◽  
Dna Chain ◽  
Relationship Of ◽  
The Relationship ◽  
Neighbour Analysis

The properties of a nuclear preparation from rat liver and thymus are described. (1) Nearest-neighbour analysis after incorporation of 32P-labelled nucleotide residues from dATP, dCTP, dGTP, dTTP and arabinofuranosyl analogues of CTP and ATP shows template-dependent DNA synthesis. (2) Where primer termini are limiting, incorporation of arabinofuranosyl analogues of AMP and CMP residues proceeds to a limit indicating that both of these analogues are DNA chain terminators. (3) No large differences have been found between the priming potentialities or the intrinsic DNA polymerase activities of nuclei from resting or regenerating liver and the relationship of this DNA synthesis in vitro to DNA replication or repair in vivo is briefly discussed.

scholarly journals The effect of chemotherapy on the kinetics and proliferative capacity of normal and tumorous tissues in vivo

Blood ◽  
1975 ◽  
Vol 45 (1) ◽  
pp. 107-118 ◽  
Author(s):  
SH Rosenoff ◽  
JM Bull ◽  
RC Young
Keyword(s):  
Bone Marrow ◽  
Dna Synthesis ◽  
Colony Formation ◽  
Antitumor Agents ◽  
Tritiated Thymidine ◽  
Chemotherapeutic Agents ◽  
Proliferative Capacity

Abstract The proliferative state of a given tissue is a major determinant of its sensitivity to both phase-specific and cycle-specific chemotherapeutic agents. To study the extent of injury induced by antitumor agents to normal and tumorous tissues, a technique for following DNA synthesis as reflected in the incorporation of tritiated thymidine (3H-TdR) into DNA was compared to the conventional radioautographic technique of the labeling index (LI) and to the functional kinetic technique of granulocyte colony formation in vitro. Alterations in DNA synthesis induced by a single dose of cyclophosphamide in normal and tumorous tissues in vivo paralleled in many respects the changes seen when the more time-consuming techniques of the LI or granulocyte colony formation were employed. However, the recovery of granulocyte colony formation after cyclophosphamide therapy laged behind the recovery of DNA synthesis in the bone marrow, obscuring a kinetic event of potential therapeutic significance. The determination of DNA synthesis simultaneously in normal and tumorous tissues in vivo was easy to perform and supplied therapeutically pertinent results comparatively quickly.

270. Androgens augment the mitogenic effects of oocyte-secreted factors and growth differentiation factor 9 on porcine granulosa cells

2005 ◽  
Vol 17 (9) ◽  
pp. 111
Author(s):  
T. E. Hickey ◽  
D. L. Marrocco ◽  
F. Amato ◽  
L. J. Ritter ◽  
R. J. Norman ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Tritiated Thymidine ◽  
Paracrine Signalling ◽  
Secreted Factors ◽  
Differentiation Factor ◽  
Porcine Granulosa Cells ◽  
Growth Differentiation Factor 9 ◽  
Growth Promoting

Androgens, acting directly through the androgen receptor (AR), are thought to promote granulosa cell (GC) growth in vivo, but generally inhibit growth and promote GC differentiation in vitro. We hypothesised that the growth-promoting action of androgens on GC requires paracrine signalling from the oocyte. To test this hypothesis, we cultured mural GC from small antral (1–3mm) pre-pubertal pig follicles in the presence or absence of denuded oocytes (DO) from the same follicles to examine whether mitogenic responses, determined by uptake of tritiated thymidine, to combinations of FSH, insulin like growth factor 1 (IGF1) and dihydrotestosterone (DHT; 500 nM), were influenced by oocyte-secreted factors (OSFs). To further explore the identity of such factors, we performed the same experiments, substituting recombinant mouse growth differentiation factor 9 (GDF9), a known OSF, for the DO. Alone, DHT induced a small (<2-fold), but consistent increase in IGF1-stimulated DNA synthesis. OSFs stimulated DNA synthesis in all experimental combinations, most significantly in the presence of IGF1 (P < 0.0001), and DHT enhanced (P<0.05) the stimulatory effect of OSFs in all instances. Like OSFs, GDF9 substantially increased IGF1-stimulated DNA synthesis (P < 0.0001), and again, DHT enhanced (P > 0.01) this effect. In further experiments, two AR agonists, testosterone (10-1000nM) and DHT (5–500 nM), dose-dependently augmented the mitogenic effect of OSFs or GDF9 in the presence of IGF1. Only the highest doses of androgen had an independent stimulatory effect; lower doses required the presence of an OSF(s). Antiandrogen (hydroxyflutamide) treatment, used to block AR activity, antagonized the androgen X GDF9 interaction. In conclusion, androgens, via activation of the AR, stimulate porcine GC proliferation in vitro by potentiating the growth-promoting effects of oocytes or GDF9. These signalling pathway interactions are likely to be important regulators of folliculogenesis in vivo and may cause the excess follicle growth that is observed in androgen-treated female animals.

A Review of the Genotoxicity of Triallate

2003 ◽  
Vol 22 (3) ◽  
pp. 233-251 ◽  
Author(s):  
Charles E. Healy ◽  
Larry D. Kier ◽  
Fabrice Broeckaert ◽  
Mark A. Martens
Keyword(s):  
Dna Synthesis ◽  
Mammalian Cells ◽  
Mutagenic Activity ◽  
Human Lymphocytes ◽  
In Vivo Studies ◽  
Weight Of Evidence ◽  
Unscheduled Dna Synthesis ◽  
Vitro Assay

Triallate is a selective herbicidal chemical used for control of wild oats in wheat. It has an extensive genotoxicity database that includes a variety of in vitro and in vivo studies. The chemical has produced mixed results in in vitro assay systems. It was genotoxic in bacterial mutation Ames assays, predominantly in Salmonella typhimurium strains TA100 and TA1535 in the presence of S9. Weaker responses have been observed in TA100 and TA1535 in the absence of S9. Mixed results have been observed in strain TA98, whereas no genotoxicity has been observed in strains TA1537 and TA1538. The presence and absence of S9 and its source seem to play a role in the bacterial response to the chemical. There have also been conflicting results in other test systems using other bacterial genera, yeast, and mammalian cells. Chromosome effects assays (sister-chromatid exchange and cytogenetics assays) have produced mixed results with S9 but no genotoxicity without S9. Triallate has not produced any genotoxicity in in vitro DNA damage or unscheduled DNA synthesis assays using EUE cells, human lymphocytes, and rat and mouse hepatocytes. In a series of in vivo genotoxicity assays (cytogenetics, micronucleus, dominant lethal, and unscheduled DNA synthesis), there has been no indication of any adverse genotoxic effect. Metabolism data indicate that the probable explanation for the differences observed between the in vitro studies with S9 and without S9 and between the in vitro and the in vivo studies is the production of a mutagenic intermediate in vitro at high doses of triallate is expected to be at most only transiently present in in vivo studies. The weight of evidence strongly suggests that triallate is not likely to exert mutagenic activity in vivo due to toxicokinetics and metabolic processes leading to detoxification.

scholarly journals The Effect of Differing Demands for Blood Cell Production on DNA Synthesis by Hemopoietic Colony-Forming Cells of Mice

Blood ◽  
1965 ◽  
Vol 26 (3) ◽  
pp. 296-308 ◽  
Author(s):  
A. J. BECKER ◽  
E. A. MCCULLOCH ◽  
L. SIMINOVITCH ◽  
J. E. TILL
Keyword(s):  
Dna Synthesis ◽  
Progenitor Cells ◽  
Fetal Liver ◽  
Tritiated Thymidine ◽  
Large Fraction ◽  
Control Mechanisms ◽  
Normal Spleen ◽  
Hemopoietic System

Abstract A technic capable of estimating the fraction of hemopoietic colony-forming progenitor cells in DNA synthesis in vivo has been described. The technic is based on the ability of tritiated thymidine to inhibit the growth of those colony-forming cells which, by virtue of their presence in the S-phase during a 20-minute incubation in vitro, in the presence of 500 µc./ml. of H3TdR, have incorporated large amounts of the nucleoside. The method has been applied to transplanted colony-forming cells proliferating in spleens of heavily irradiated recipients as well as to cells from normal fetal liver, normal marrow, and normal spleen. In situations where the hemopoietic system is expanding (fetal liver and regenerating transplants), a large fraction, 40-65 per cent, of the stem cells are in DNA synthesis. In the steady-state situations (adult marrow and spleen), the fraction of cells in DNA synthesis is almost imperceptible using this technic. It is concluded that control mechanisms which govern the rate of hemopoiesis operate, at least in part, by altering the generative cycle of blood-forming progenitor cells.

Premeiosis and premeiotic DNA synthesis in the left ovary of the female chick embryo

Development ◽  
1967 ◽  
Vol 18 (3) ◽  
pp. 299-304
Author(s):  
M. Callebaut
Keyword(s):  
Chick Embryo ◽  
Dna Synthesis ◽  
Germ Cells ◽  
Tritiated Thymidine ◽  
Modified Technique ◽  
Distinctive Structure ◽  
Series Of Experiments ◽  
Prophase Of Meiosis

Premeiotic DNA synthesis in the germ cells of the female mouse embryo has been studied by Peters, Levy & Crone (1962) and Crone, Levy & Peters (1965). In this species, with a close synchronization in germinal development, the process of oogenesis which is the period of multiplication by mitotic divisions of the germ cells (oogonia) seems to be followed rapidly (within 24 h) by the first step of the prophase of meiosis (see Borum, 1961). In previous work (Callebaut & Dubois, 1965; Callebaut, 1967) we have investigated DNA synthesis in the ovarian germ cells of the chick embryo, both in vitro and in vivo, by autoradiography following the incorporation of tritiated thymidine. In a new series of experiments with a modified technique, it has been possible to demonstrate that the nuclei of the germ cells in premeiotic S phase in the female chick embryo have a distinctive structure.

Utility of Preinjection Aspiration for Hyaluronic Fillers: A Novel In Vivo Human Evaluation

2020 ◽  
Vol 24 (4) ◽  
pp. 367-371 ◽  
Author(s):  
Jordan V. Wang ◽  
Ezra Hazan ◽  
Georgette Hattier ◽  
Richard L. Torbeck ◽  
Hooman Khorasani ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Complex Modulus ◽  
Waiting Times ◽  
Human Model ◽  
Peripheral Vein ◽  
Vitro Model ◽  
The Times ◽  
Time Required

Background Hyaluronic acid (HA) fillers have increased in popularity. While complications are rare, practitioners should focus on their prevention. Preinjection aspiration remains controversial as an effective safety checkpoint. Objectives Our study investigated the utility of preinjection aspiration as a safety checkpoint for HA fillers through comparison of physiochemical and rheological properties in a novel in vivo human model. Methods An in vivo human model consisted of a cannula inserted into a peripheral vein. Preinjection aspiration was evaluated using syringes of 10 commonly used HA fillers. The time required to visualize a flash was recorded. Results Using a multivariable regression model, needle gauge, HA concentration, elastic modulus ( G′), viscous modulus ( G″), and complex modulus ( G*) had significant relationships with time to flash, whereas pullback volume did not. However, when comparing pullback volume using a more appropriate paired analysis, 0.5 cc pullback volume had a significantly decreased time to flash than 0.2 cc. Conclusions Preinjection aspiration for HA fillers has utility as a safety checkpoint. The times to visualize flashback decreased when using a human peripheral vein model compared to a previous in vitro model, suggesting that there may be real-time clinical utility of preinjection aspiration. Waiting times to visualize flashback may be affected by physiochemical and rheological properties. Additional studies would help to validate our results.

Effect of inhibin on rat testicular desoxyribonucleic acid (DNA) synthesis in vivo and in vitro

1981 ◽  
Vol 98 (2) ◽  
pp. 312-320 ◽  
Author(s):  
P. Franchimont ◽  
F. Croze ◽  
A. Demoulin ◽  
R. Bologne ◽  
J. Hustin
Keyword(s):  
Dna Synthesis ◽  
Thymidine Incorporation ◽  
Specific Activity ◽  
Tritiated Thymidine ◽  
Biological Properties ◽  
Rete Testis ◽  
Thymidine Uptake ◽  
Adult Rats

Abstract. When injected in vivo 3 h before sacrifice or when incubated in vitro with testicular fragments for 3 h, tritiated thymidine, a reliable index of DNA synthesis and of mitotic activity, was incorporated into the DNA of differentiated spermatogonia, as shown by autohistoradiography. The maximum DNA specific activity was obtained in pubertal rats aged 42 days, weight 150 g. Two preparations of inhibin extracted from ram rete testis fluid (RTF) of different molecular weight (> 10 000 for RTF1 and < 5000 for RTF3) but which possess the same biological properties were investigated for their effect on thymidine uptake in vivo and in vitro. In vivo both preparations specifically inhibited tritiated thymidine incorporation into testicular DNA of pubertal animals (42 days). No change in thymidine uptake into hepatic DNA was observed. Tritiated thymidine incorporation into testicular DNA was lower in normal adult rats and in hypophysectomized pubertal animals. RTF1 and RTF3 did not affect thymidine incorporation in either case. The reasons for this lack of effect are discussed. In vitro, both preparations induced a dose-dependent decrease in DNA synthesis in testis fragments from rats aged 42 and 49 days. The preparations lost their in vivo and in vitro inhibitory effects when denatured by heating and trypsin digestion. The inhibin preparations probably reduced testicular DNA synthesis and spermatogonial multiplication by reducing FSH secretion in vivo but also had a direct effect on the germ cells as shown by the in vitro experiments. These in vivo and in vitro actions of inhibin preparations are similar to those of the testicular chalones. The relationship which might exist between inhibin and the chalones is discussed.

scholarly journals The effect of chemotherapy on the kinetics and proliferative capacity of normal and tumorous tissues in vivo

Blood ◽  
1975 ◽  
Vol 45 (1) ◽  
pp. 107-118
Author(s):  
SH Rosenoff ◽  
JM Bull ◽  
RC Young
Keyword(s):  
Bone Marrow ◽  
Dna Synthesis ◽  
Colony Formation ◽  
Antitumor Agents ◽  
Tritiated Thymidine ◽  
Chemotherapeutic Agents ◽  
Proliferative Capacity

The proliferative state of a given tissue is a major determinant of its sensitivity to both phase-specific and cycle-specific chemotherapeutic agents. To study the extent of injury induced by antitumor agents to normal and tumorous tissues, a technique for following DNA synthesis as reflected in the incorporation of tritiated thymidine (3H-TdR) into DNA was compared to the conventional radioautographic technique of the labeling index (LI) and to the functional kinetic technique of granulocyte colony formation in vitro. Alterations in DNA synthesis induced by a single dose of cyclophosphamide in normal and tumorous tissues in vivo paralleled in many respects the changes seen when the more time-consuming techniques of the LI or granulocyte colony formation were employed. However, the recovery of granulocyte colony formation after cyclophosphamide therapy laged behind the recovery of DNA synthesis in the bone marrow, obscuring a kinetic event of potential therapeutic significance. The determination of DNA synthesis simultaneously in normal and tumorous tissues in vivo was easy to perform and supplied therapeutically pertinent results comparatively quickly.

Vacuoles Induced in Mammalian Cells by Helicobacter Cytotoxin are Acidic Organelles

1990 ◽  
Vol 48 (3) ◽  
pp. 168-169
Author(s):  
M. H. Chestnut ◽  
C. E. Catrenich
Keyword(s):  
Acridine Orange ◽  
Mammalian Cells ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Ulcer Disease ◽  
Gastroduodenal Disease ◽  
H Pylori

Helicobacter pylori is a non-invasive, Gram-negative spiral bacterium first identified in 1983, and subsequently implicated in the pathogenesis of gastroduodenal disease including gastritis and peptic ulcer disease. Cytotoxic activity, manifested by intracytoplasmic vacuolation of mammalian cells in vitro, was identified in 55% of H. pylori strains examined. The vacuoles increase in number and size during extended incubation, resulting in vacuolar and cellular degeneration after 24 h to 48 h. Vacuolation of gastric epithelial cells is also observed in vivo during infection by H. pylori. A high molecular weight, heat labile protein is believed to be responsible for vacuolation and to significantly contribute to the development of gastroduodenal disease in humans. The mechanism by which the cytotoxin exerts its effect is unknown, as is the intracellular origin of the vacuolar membrane and contents. Acridine orange is a membrane-permeant weak base that initially accumulates in low-pH compartments. We have used acridine orange accumulation in conjunction with confocal laser scanning microscopy of toxin-treated cells to begin probing the nature and origin of these vacuoles.

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