DEOXYRIBONUCLEIC ACID LABELLING AFTER TRITIATED THYMIDINE INJECTION

1966 ◽  
Vol 44 (3) ◽  
pp. 451-454 ◽  
Author(s):  
N. Brière ◽  
H. Isler
Keyword(s):  
Tissue Culture ◽  
Deoxyribonucleic Acid ◽  
Tritiated Thymidine ◽  
Time Intervals ◽  
Young Rats ◽  
Highly Sensitive

Young rats were injected with thymidine-3H and the level of radioactivity in their blood was measured by a highly sensitive radioautographic technique. Radioactivity (10−6 μcurie/ml) was still detected in serum 7 days after injection. To determine whether the blood of these rats contained deoxyribonucleic acid (DNA) precursors, the sera, taken at various time intervals after injection, were introduced into tissue culture chambers. By radioautography of these cultures, it was found that they contained cells with labelled nuclei, even when exposed to sera taken 30 hours after injection. The presence of nuclear precursors in these sera probably indicates a reutilization of DNA from other cells.

Departure Time Choice in Schedule-Based Transit Assignment

2021 ◽  
pp. 036119812110338
Author(s):  
Markus Friedrich ◽  
Matthias Schmaus ◽  
Jonas Sauer ◽  
Tobias Zündorf
Keyword(s):  
Travel Demand ◽  
Time Intervals ◽  
Transit Assignment ◽  
Common Assumption ◽  
Adaptation Time ◽  
Highly Sensitive ◽  
Departure Time ◽  
Departure Time Choice ◽  
Passenger Behavior ◽  
The Impact

This paper investigates existing departure time models for a schedule-based transit assignment and their parametrization. It analyzes the impact of the temporal resolution of travel demand and suggests functions for evaluating the adaptation time as part of the utility of a path. The adaptation time quantifies the time between the preferred and the scheduled departure times. The findings of the analysis suggested that travel demand should be discretized into intervals of 1 min, with interval borders right between the full minute, that is, ±0.5 min. It was shown that longer time intervals led to arbitrary run volumes, even for origin–destination pairs with just one transit line and a fixed headway. Although a linear relationship between adaptation time and adaptation disutility is a common assumption in several publications, it cannot represent certain types of passenger behavior. For some trip purposes, passengers may be insensitive to small adaptation times, but highly sensitive to large adaptations. This requires a nonlinear evaluation function.

INCORPORATION OF RADIOACTIVE PURINE AND PYRIMIDINE BASES AND OF THYMIDINE INTO THE DEOXYRIBONUCLEIC ACID OF SALMON MILTS

1964 ◽  
Vol 42 (1) ◽  
pp. 51-57 ◽  
Author(s):  
H. L. A. Tarr
Keyword(s):  
Orotic Acid ◽  
Deoxyribonucleic Acid ◽  
Tritiated Thymidine ◽  
Experimental Conditions ◽  
Live Fish ◽  
Pyrimidine Bases

C14-labeled adenine, guanine and cytosine, and tritiated thymidine were incorporated into the deoxyribonucleic acid of salmon milts, either by injection into the milts of live fish or into excised milts. The amount incorporated was very small. Under the experimental conditions radioactive nucleosides, deoxyuridine, adenosine 5′-mono- and tri-phosphates, orotic acid, uracil, ribose 1-phosphate, and ribose 5-phosphate were not incorporated. It is suggested that these results may be due to the comparative impermeability of the cells to the various compounds.

scholarly journals The photocarcinogenicity of anthracence: photochemical binding to deoxyribonucleic acid in tissue culture

1975 ◽  
Vol 149 (1) ◽  
pp. 289-291 ◽  
Author(s):  
G M Blackburn ◽  
P E Taussig
Keyword(s):  
Molecular Weight ◽  
Tissue Culture ◽  
High Molecular Weight ◽  
Deoxyribonucleic Acid ◽  
Radiation Doses ◽  
Mammalian Tissue ◽  
Hydrocarbon Molecule ◽  
High Radiation ◽  
High Molecular Weight Dna ◽  
Low Radiation Doses

Anthracene becomes covalently bound to high-molecular-weight DNA in mammalian tissue culture as a result of irradiation at 365 nm after the incubation of cells with the hydrocarbon. At high radiation doses, the extent of binding exceeds one hydrocarbon molecule per 103 bases, and is lethal. At low radiation doses, much decreased binding is observed, but a majority of cells remain viable and can be recultured.

EFFECTS OF A GLUCOCORTICOID (DEXAMETHASONE) ON THE EOSINOPHILS OF THE RAT

1967 ◽  
Vol 37 (4) ◽  
pp. 463-469 ◽  
Author(s):  
EVELYN C. BLENKINSOPP ◽  
W. K. BLENKINSOPP
Keyword(s):  
Continuous Infusion ◽  
Deoxyribonucleic Acid ◽  
Tritiated Thymidine ◽  
Blood Eosinophil ◽  
Consequent Reduction ◽  
Reticulo Endothelial System ◽  
Eosinophil Counts

SUMMARY The effects of single and continuous administrations of a synthetic gluco-corticoid (dexamethasone) on eosinophil numbers and distribution have been studied. Absolute blood eosinophil counts were made, and the turnover of the eosinophils was examined by continuous infusion of tritiated thymidine to label the deoxyribonucleic acid of all newly formed cells. Dexamethasone equivalent to less than 200 μg. cortisone/100 g. rat/day produced disappearance of eosinophils from the blood and the normal output of glucocorticoids is therefore probably less than this. Single administrations of dexamethasone produced a blood eosinopenia within 2 hr. due to removal and destruction of eosinophils by the reticulo-endothelial system. Continuous dexamethasone administration reduced the number of proliferating eosinophil cells in the marrow, with a consequent reduction in the number of eosinophils in the tissues.

Duration of Availability of Tritiated Thymidine Following Intraperitoneal Injection

1968 ◽  
Vol 3 (1) ◽  
pp. 89-93
Author(s):  
W. K. BLENKINSOPP
Keyword(s):  
Cell Division ◽  
Intraperitoneal Injection ◽  
Deoxyribonucleic Acid ◽  
Direct Evidence ◽  
Tritiated Thymidine ◽  
Indirect Evidence ◽  
Acid Synthesis ◽  
Single Intraperitoneal Injection ◽  
Deoxyribonucleic Acid Synthesis

Much indirect evidence supports the assumption that tritiated thymidine does not label cells which enter the deoxyribonucleic acid synthesis phase (S) more than 1 h after injection. Direct evidence confirming this assumption was obtained by counting labelled epithelial nuclei in mice killed 1, 4 or 6 h after a single intraperitoneal injection of [3H]thymidine; colchicine was used to prevent the increase in number of labelled nuclei which would otherwise have occurred because of cell division. The proportion of cells labelled was the same at 1 h as at 4 or 6 h after injection of [3H]thymidine. Nuclei were regarded as labelled if they were overlaid by 4 grains or more; comparison of nuclear and background labelling indicated that nuclei overlaid by 3 grains or less represented background labelling.

scholarly journals Use of ELISA to Detect Toxigenic Pasteurella Multocida in Atrophic Rhinitis in Swine

1992 ◽  
Vol 4 (4) ◽  
pp. 419-422 ◽  
Author(s):  
Terry L. Bowersock ◽  
Tom Hooper ◽  
Ronald Pottenger
Keyword(s):  
Tissue Culture ◽  
Pasteurella Multocida ◽  
Atrophic Rhinitis ◽  
Enzyme Linked Immunosorbent Assay ◽  
Cytotoxicity Assays ◽  
Highly Sensitive ◽  
Nasal Secretions ◽  
Toxigenic Strains ◽  
Swine Herds ◽  
Toxigenic Pasteurella Multocida

The use of an enzyme-linked immunosorbent assay (ELISA) as a means of detecting dermone-crotoxin-producing strains of Pasteurella multocida was investigated. The assay was evaluated as a means to identify toxigenic P. multocida isolates recovered from nasal secretions of swine with atrophic rhinitis. The sensitivity and specificity of the ELISA for detecting dermonecrotoxin-producing P. multocida strains were compared to those of mouse-inoculation and cytotoxicity assays. The ELISA was highly sensitive and more specific than animal inoculation or tissue culture assay and is thus a more effective method for screening swine herds for the presence of toxigenic strains of P. multocida. The ELISA is a rapid, effective, economical way to identify toxigenic P. multocida isolates.

scholarly journals THE REPLICATION TIME AND PATTERN OF CARCINOGEN-INDUCED HEPATOMA CELLS

1964 ◽  
Vol 22 (2) ◽  
pp. 341-350 ◽  
Author(s):  
Joseph Post ◽  
Joseph Hoffman
Keyword(s):  
Tumor Cell ◽  
Dna Synthesis ◽  
Tumor Cells ◽  
Cell Population ◽  
Tritiated Thymidine ◽  
Normal Liver ◽  
Hepatoma Cells ◽  
Male Rats ◽  
Time Intervals ◽  
Replication Time

The replication time and pattern have been investigated in hepatoma cells induced by feeding 3'Me-DAB to male rats for 5 months. With the use of tritiated thymidine as a DNA label along with autoradiography, mitotic nuclear labeling has been studied 0.5 to 72 hours after the administration of the label. The following time intervals have been estimated: replication time, 31 hours; DNA synthesis, 17 hours; G2 plus Mitosis, 2 hours; G1, 12 hours. Only about 8 per cent of the tumor cell (interphase) population is "flash" labeled, following a single dose of 50 µC of H3TDR. This group of cells has been followed through three cycles of division. The repeated rhythmic passage of tumor cells through cell division is similar to that previously reported for normal liver cells in the growing rat. However, tumor cells have longer replication and DNA synthesis times. In addition, the several time intervals studied vary more in the tumor cell population than they do in the growing normal cell population.

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