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.

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.

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.

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.

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.

Thrombopoietin-Induced Stimulation of Megakaryocyte- Enriched Bone Marrow Cultures

1979 ◽  
Author(s):  
K. L. Kellar ◽  
B. L. Evatt ◽  
C. R. McGrath ◽  
R. B. Ramsey
Keyword(s):  
Bone Marrow ◽  
Dna Synthesis ◽  
Bone Marrow Cells ◽  
Rabbit Plasma ◽  
Bone Marrow Cultures ◽  
Plasma Fractions ◽  
Marrow Cultures ◽  
Stimulation Of

Liquid cultures of bone marrow cells enriched for megakaryocytes were assayed for incorporation of 3H-thymidine (3H-TdR) into acid-precipitable cell digests to determine the effect of thrombopoietin on DNA synthesis. As previously described, thrombopoietin was prepared by ammonium sulfate fractionation of pooled plasma obtained from thrombocytopenic rabbits. A control fraction was prepared from normal rabbit plasma. The thrombopoietic activity of these fractions was determined in vivo with normal rabbits as assay animals and the rate of incorporation of 75Se-selenomethionine into newly formed platelets as an index of thrombopoietic activity of the infused material. Guinea pig megakaryocytes were purified using bovine serum albumin gradients. Bone marrow cultures containing 1.5-3.0x104 cells and 31%-71% megakaryocytes were incubated 18 h in modified Dulbecco’s MEM containing 10% of the concentrated plasma fractions from either thrombocytopenic or normal rabbits. In other control cultures, 0.9% NaCl was substituted for the plasma fractions. 3H-TdR incorporation was measured after cells were incubated for 3 h with 1 μCi/ml. The protein fraction containing thrombopoietin-stimulating activity caused a 25%-31% increase in 3H-TdR incorporation over that in cultures which were incubated with the similar fraction from normal plasma and a 29% increase over the activity in control cultures to which 0.9% NaCl had been added. These data suggest that thrombopoietin stimulates DNA synthesis in megakaryocytes and that this tecnique may be useful in assaying thrombopoietin in vitro.

scholarly journals RuvAB and RecG Are Not Essential for the Recovery of DNA Synthesis Following UV-Induced DNA Damage in Escherichia coli

Genetics ◽  
2004 ◽  
Vol 166 (4) ◽  
pp. 1631-1640 ◽  
Author(s):  
Janet R Donaldson ◽  
Charmain T Courcelle ◽  
Justin Courcelle
Keyword(s):  
Dna Damage ◽  
Dna Synthesis ◽  
Dna Lesions ◽  
Replication Forks ◽  
Wild Type ◽  
Replication Machinery ◽  
Dna Junctions ◽  
Fork Regression

Abstract Ultraviolet light induces DNA lesions that block the progression of the replication machinery. Several models speculate that the resumption of replication following disruption by UV-induced DNA damage requires regression of the nascent DNA or migration of the replication machinery away from the blocking lesion to allow repair or bypass of the lesion to occur. Both RuvAB and RecG catalyze branch migration of three- and four-stranded DNA junctions in vitro and are proposed to catalyze fork regression in vivo. To examine this possibility, we characterized the recovery of DNA synthesis in ruvAB and recG mutants. We found that in the absence of either RecG or RuvAB, arrested replication forks are maintained and DNA synthesis is resumed with kinetics that are similar to those in wild-type cells. The data presented here indicate that RecG- or RuvAB-catalyzed fork regression is not essential for DNA synthesis to resume following arrest by UV-induced DNA damage in vivo.

Vasopressin-induced pulmonary vasodilation in rats

1989 ◽  
Vol 257 (2) ◽  
pp. H415-H422 ◽  
Author(s):  
B. R. Walker ◽  
J. Haynes ◽  
H. L. Wang ◽  
N. F. Voelkel
Keyword(s):  
Hypoxic Pulmonary Vasoconstriction ◽  
Systemic Resistance ◽  
Constant Infusion ◽  
Bolus Administration ◽  
Pulmonary Hemodynamics ◽  
Pulmonary Vasodilation ◽  
Isolated Lung ◽  
Series Of Experiments

Experiments were performed to determine the pulmonary vascular responses to exogenous or endogenous arginine vasopressin (AVP) in rats. Both in vitro and in vivo approaches were used to examine the direct pulmonary vasoactive properties of AVP and how those properties affect pulmonary hemodynamics in the intact animal. In conscious, unrestrained rats, constant infusion of AVP (4.0 mU.kg-1.min-1 iv) resulted in a fall in mean pulmonary artery pressure (PAP), although systemic pressure was increased. Coincident with the fall in PAP were similar reductions in cardiac output and heart rate. Similarly, bolus administration of AVP reduced PAP, and this effect was augmented during hypoxia. Another series of experiments examined the effect of endogenous AVP released by arterial hypoxemia on pulmonary hemodynamics in conscious rats. Administration of a specific V1-vasopressinergic antagonist had no effect on the PAP response to hypoxia; however, systemic resistance tended to fall following V1-antagonism. To determine the vasoactive properties of AVP independent of these changes in blood flow, a series of experiments were performed on isolated, perfused rat lungs. Injection of 25, 200, or 2,000 mU of AVP into the circulation of the isolated lung was without effect under normoxic conditions. In contrast, 25 mU AVP elicited reproducible pulmonary vasodilation when injected during ongoing hypoxic pulmonary vasoconstriction. This vasodilatory response was unaffected by meclofenamate or by the platelet-activating factor receptor antagonist SRI 63-441, but was blocked by a specific V1-vasopressinergic antagonist. We conclude that although AVP exerts profound systemic vasoconstriction, the pulmonary circulation appears relatively unaffected by exogenous or endogenous AVP in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Birth of healthy twins after fertilization with in vitro cultured spermatids from a patient with massive in vivo apoptosis of postmeiotic germ cells

2000 ◽  
Vol 74 (5) ◽  
pp. 1044-1046 ◽  
Author(s):  
Jan Tesarik ◽  
Natalio Cruz-Navarro ◽  
Eduardo Moreno ◽  
Maria Teresa Cañete ◽  
Carmen Mendoza
Keyword(s):  
Germ Cells
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