COMPARISON OF THE EFFECTS OF VISIBLE, ULTRAVIOLET, AND X-RADIATION ON RAT THYMOCYTES

1964 ◽  
Vol 42 (4) ◽  
pp. 529-543 ◽  
Author(s):  
D. K. Myers ◽  
Donna DeWolfe-Slade
Keyword(s):  
Nucleic Acid ◽  
Visible Light ◽  
Ultraviolet Light ◽  
Intact Cell ◽  
Lethal Effect ◽  
Low Doses ◽  
X Irradiation ◽  
Thymus Cells ◽  
Ultraviolet Energy

Ultraviolet and X-irradiation produce many of the same effects on rat thymocytes in vitro. Exposure of the cells to low doses results in a latent lethal effect, which requires incubation at 37 °C for its expression, and in an apparent increase in the rate at which deoxyribonucleoprotein from the cells dissolves to form a gel in 2 M NaCl. As the doses are increased, a decrease in the viscosity of the deoxyribonucleoprotein gel, an immediate "death" and swelling of the cells, and an immediate destruction of nucleotide bases become evident. For either radiation, doses which do not appear to have any immediate effect on the intact cell lead to loss of soluble materials (potassium ion, ribonucleotides) from the cells after incubation at 37 °C for several hours. The amount of ultraviolet energy required to produce most of the above effects is nearly 1000 times greater than the amount of X-ray energy required to produce the same effect.Three differences between the effects of ultraviolet and X-irradiation were observed: Ultraviolet light was relatively inefficient in breaking down the long deoxyribonucleoprotein chains but appeared to destroy hydrogen-bonding in the native nucleic acid structure at the same time as it destroyed the nucleotide basis. Moreover, the lethal effects of low doses of ultraviolet light on thymus cells require a longer time to develop than do the effects of X-irradiation.Thymocytes can also be killed by high intensities of visible light, particularly in the presence of photoreducible dyes. However, visible light produces little or no latent damage to the cells, nor was any evidence of nucleic acid damage observed.

THE LETHAL EFFECT OF LONGWAVE ULTRAVIOLET LIGHT AND PUVA. AN ANALYSIS BASED UPON HUMAN MESENCHYMAL CELLS IN VITRO

1984 ◽  
Vol 39 (5) ◽  
pp. 625-629
Author(s):  
G. de Jongh ◽  
MIEKE BERGERS ◽  
J. B. M. Boezeman ◽  
A. R. Verhagen ◽  
P. D. Mier
Keyword(s):  
Ultraviolet Light ◽  
Lethal Effect ◽  
Mesenchymal Cells

scholarly journals STUDIES ON THE TRANSFER OF LYMPH NODE CELLS

1958 ◽  
Vol 108 (1) ◽  
pp. 21-36 ◽  
Author(s):  
T. N. Harris ◽  
Susanna Harris ◽  
Miriam B. Farber
Keyword(s):  
Lymph Node ◽  
Complete Suppression ◽  
Cell Transfer ◽  
X Irradiation ◽  
Lymph Node Cells ◽  
Partial Suppression ◽  
Injection Effect ◽  
Thymus Cells ◽  
Made In

The transfer to rabbits of homologous lymph node cells which have been incubated in vitro with Shigella-trypsin filtrate leads to the appearance of agglutinins to Shigella in the sera of the recipients. In the present study it has been found that the prior injection of the prospective recipients with blood leucocytes from the donor animals prevented the appearance of anti-Shigella agglutinins. The following observations have been made in this system: 1. The degree of the pre-injection effect was found to be a function of the number of leucocytes injected and of the interval between such pre-injection and the transfer of the antigen-incubated lymph node cells. 2. The pre-injection of leucocytes at appropriate intervals could also cause the failure of antibody to appear in sera of recipients of lymph node cells when these were obtained from donor rabbits injected with Shigella, 1, 2, or 3 days prior to cell transfer. 3. Agglutinins failed to appear in cell-transfer experiments after the pre-injection not only of blood leucocytes, but also of lymph node cells, peritoneal exudate cells, or thymus cells of rabbits. This effect was not brought about by pre-injection of erythrocytes of rabbits or leucocytes of chicken, cow, or horse. The pre-injection of leucocytes of human blood had an effect of partial suppression. 4. When the leucocytes for pre-injection were pooled from groups of rabbits, either the prospective donors of the lymph node cells or other rabbits, essentially complete suppression of agglutinin titers occurred regularly. When the leucocytes for pre-injection were obtained from an individual rabbit and the lymph node cells from another rabbit the suppression of the recipients' titers occurred sporadically. 5. When the recipient's own leucocytes were pre-injected the subsequent agglutinin titers were somewhat lower than those of the non-pre-injected controls. When the recipient's whole blood was re-injected as the source of leucocytes the subsequent agglutinin titers were as high as those of the non-pre-injected controls. 6. The pre-injection effect was not obtained if the leucocytes had been heated, frozen and thawed, suspended in distilled water, lyophilized, or treated with sodium iodoacetate. However, sonic oscillation or x-irradiation of the leucocytes had no effect on their capacity to bring about the pre-injection effect.

NUCLEIC ACID SYNTHESIS IN X-IRRADIATED THYMOCYTES

1966 ◽  
Vol 44 (6) ◽  
pp. 839-852 ◽  
Author(s):  
D. K. Myers ◽  
Kirsten Skov
Keyword(s):  
Dna Synthesis ◽  
Rna Synthesis ◽  
Acid Synthesis ◽  
X Irradiation ◽  
High Concentrations ◽  
Effects Of Radiation ◽  
Inhibition Of Dna Synthesis ◽  
Thymus Cells ◽  
Rna And Dna

The rate of incorporation of thymidine into the deoxyribonucleic acid (DNA) of rat thymocytes in vitro was not immediately affected by low doses of X-radiation, but became progressively more inhibited as the irradiated cells were incubated at 37 °C for periods of up to 6 hours. Ribonucleic acid (RNA) synthesis deteriorated almost at the same rate as DNA synthesis after X-irradiation in vitro, but protein synthesis was slightly more resistant. Addition of 10–50 mM nicotinamide to the irradiated cell suspensions tended to retard the development of this inhibition, particularly at low temperatures, but high concentrations of nicotinamide were also toxic to these cells. The inhibition of DNA synthesis by X-irradiation appeared to follow a qualitatively similar pattern in thymus, spleen, and regenerating liver in vivo.In addition to the inhibition resulting from degenerative processes in the irradiated cells, DNA synthesis in vitro was directly inhibited by 20–30 kr X-radiation. The effects of radiation on DNA synthesis paralleled to some extent its effects on the gel-forming capacity of the deoxyribonucleoprotein from the thymus cells. It is suggested that the normal synthesis of both RNA and DNA in thymocytes depends on the integrity of the deoxyribonucleoprotein.

Ultrastructural Changes in Three Different Mammalian Cells Following Ultraviolet Laser Irradiation

1972 ◽  
Vol 30 ◽  
pp. 350-351
Author(s):  
K. Shankar Narayan ◽  
Kailash C. Gupta ◽  
Tohru Okigaki
Keyword(s):  
Ultraviolet Light ◽  
Mammalian Cells ◽  
Biological Effects ◽  
Survival Rates ◽  
Chinese Hamster ◽  
Cell Types ◽  
Differential Sensitivity ◽  
Ultrastructural Changes ◽  
Ultraviolet Laser

The biological effects of short-wave ultraviolet light has generally been described in terms of changes in cell growth or survival rates and production of chromosomal aberrations. Ultrastructural changes following exposure of cells to ultraviolet light, particularly at 265 nm, have not been reported.We have developed a means of irradiating populations of cells grown in vitro to a monochromatic ultraviolet laser beam at a wavelength of 265 nm based on the method of Johnson. The cell types studies were: i) WI-38, a human diploid fibroblast; ii) CMP, a human adenocarcinoma cell line; and iii) Don C-II, a Chinese hamster fibroblast cell strain. The cells were exposed either in situ or in suspension to the ultraviolet laser (UVL) beam. Irradiated cell populations were studied either "immediately" or following growth for 1-8 days after irradiation.Differential sensitivity, as measured by survival rates were observed in the three cell types studied. Pattern of ultrastructural changes were also different in the three cell types.

High resolution mapping of nucleic acid containing complexes in vitro and in situ

1996 ◽  
Vol 54 ◽  
pp. 48-49
Author(s):  
D. P. Bazett-Jones ◽  
M. J. Hendzel
Keyword(s):  
Nucleic Acid ◽  
High Resolution ◽  
Transcription Initiation ◽  
Molecular Mechanisms ◽  
Heavy Atom ◽  
Regulation Of Transcription ◽  
High Exposure ◽  
Resolution Mapping ◽  
Tata Sequence

Structural analysis of combinations of nucleosomes and transcription factors on promoter and enhancer elements is necessary in order to understand the molecular mechanisms responsible for the regulation of transcription initiation. Such complexes are often not amenable to study by high resolution crystallographic techniques. We have been applying electron spectroscopic imaging (ESI) to specific problems in molecular biology related to transcription regulation. There are several advantages that this technique offers in studies of nucleoprotein complexes. First, an intermediate level of spatial resolution can be achieved because heavy atom contrast agents are not necessary. Second, mass and stoichiometric relationships of protein and nucleic acid can be estimated by phosphorus detection, an element in much higher proportions in nucleic acid than protein. Third, wrapping or bending of the DNA by the protein constituents can be observed by phosphorus mapping of the complexes. Even when ESI is used with high exposure of electrons to the specimen, important macromolecular information may be provided. For example, an image of the TATA binding protein (TBP) bound to DNA is shown in the Figure (top panel). It can be seen that the protein distorts the DNA away from itself and much of its mass sits off the DNA helix axis. Moreover, phosphorus and mass estimates demonstrate whether one or two TBP molecules interact with this particular promoter TATA sequence.

Effect of X-irradiation on gene expression of rat liver chemokines: in vivo and in vitro studies

2008 ◽  
Vol 46 (01) ◽  
Author(s):  
F Moriconi ◽  
H Christiansen ◽  
H Christiansen ◽  
N Sheikh ◽  
J Dudas ◽  
...  
Keyword(s):  
Gene Expression ◽  
Rat Liver ◽  
In Vitro Studies ◽  
X Irradiation

In vitro evaluation of hexitol nucleic acid antisense oligonucleotides

1999 ◽  
Author(s):  
Arthur Van Aerschot ◽  
Mark Vandermeeren ◽  
Johan Geysen ◽  
Walter Luyten ◽  
Marc Miller ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Antisense Oligonucleotides ◽  
In Vitro Evaluation

Genetically Encoded RNA Nanodevices for Cellular Imaging and Regulation

Nanoscale ◽  
2021 ◽  
Author(s):  
Qikun Yu ◽  
Kewei Ren ◽  
Mingxu You
Keyword(s):  
Nucleic Acid ◽  
Cellular Imaging ◽  
Synthetic Dna

Nucleic acid-based nanodevices have been widely used in the fields of biosensing and nanomedicine. Traditionally, the majority of these nanodevices were first constructed in vitro using synthetic DNA or RNA...

scholarly journals β-Cyclodextrin/Triclosan Complex-Grafted Methacrylated Glycol Chitosan Hydorgel by Photocrosslinking via Visible Light Irradiation for a Tissue Bio-Adhesive

2021 ◽  
Vol 22 (2) ◽  
pp. 700
Author(s):  
Young Jae Moon ◽  
Sun-Jung Yoon ◽  
Jeung-Hyun Koo ◽  
Yihyun Yoon ◽  
Hye Jun Byun ◽  
...  
Keyword(s):  
Wound Healing ◽  
Bacterial Infection ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Tissue Adhesive ◽  
Proton Nuclear Magnetic Resonance ◽  
Scanning Calorimetry ◽  
Glycol Chitosan

Accelerating wound healing with minimized bacterial infection has become a topic of interest in the development of the new generation of tissue bio-adhesives. In this study, we fabricated a hydrogel system (MGC-g-CD-ic-TCS) consisting of triclosan (TCS)-complexed beta-cyclodextrin (β-CD)-conjugated methacrylated glycol chitosan (MGC) as an antibacterial tissue adhesive. Proton nuclear magnetic resonance (1H NMR) and differential scanning calorimetry (DSC) results showed the inclusion complex formation between MGC-g-CD and TCS. The increase of storage modulus (G’) of MGC-g-CD-ic-TCS after visible light irradiation for 200 s indicated its hydrogelation. The swollen hydrogel in aqueous solution resulted in two release behaviors of an initial burst and sustained release. Importantly, in vitro and in vivo results indicated that MGC-g-CD-ic-TCS inhibited bacterial infection and improved wound healing, suggesting its high potential application as an antibacterial tissue bio-adhesive.

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