Rate of radiolysis of the disulphide groups of chymotrypsinogen in aqueous solutions exposed to X-irradiation

1969 ◽  
Vol 34 (1) ◽  
pp. 158-167
Author(s):  
A. Fojtík ◽  
R. Brdička ◽  
Z. Spurný
Keyword(s):  
Aqueous Solutions ◽  
X Irradiation

IRRADIATION OF DIPHOSPHOPYRIDINE NUCLEOTIDE IN DILUTE AQUEOUS SOLUTIONS

1960 ◽  
Vol 38 (11) ◽  
pp. 1255-1263 ◽  
Author(s):  
D. K. Myers
Keyword(s):  
Absorption Spectrum ◽  
Aqueous Solutions ◽  
Ultraviolet Absorption ◽  
Ultraviolet Absorption Spectrum ◽  
Ph Values ◽  
In Vivo Experiments ◽  
X Irradiation ◽  
Dilute Aqueous Solutions

In extension of previous in vivo experiments, the effects of X irradiation on DPN were studied in vitro. No correlation between the effects on the ultraviolet absorption spectrum and on the coenzyme function of DPN was evident after irradiation at different pH values. However, the loss of coenzyme function could be correlated with the destruction of ribose and of riboside linkages. Catalase did not provide greater protection than did other proteins. It was concluded that the observed loss of DPN from irradiated cells is not due to the radiosensitivity of the DPN molecule itself.

X-Ray Induced Luminescence in Aqueous Solutions of Aminobenzoic Acids

1974 ◽  
Vol 29 (3-4) ◽  
pp. 245-253 ◽  
Author(s):  
W. A. Prütz
Keyword(s):  
Aqueous Solutions ◽  
Light Emission ◽  
Quantum Yields ◽  
Spectral Change ◽  
X Ray ◽  
Fluorescence Quantum Yields ◽  
Aminobenzoic Acids ◽  
X Irradiation ◽  
Related Compounds ◽  
Absolute Fluorescence

Light emission induced by x-irradiation of deaerated aqueous solutions of anthranilic acid (AH) is predominantly due to chemiluminescence. Within the range of pH 3.5 to pH 12 only emission of the anion (A-) is observed, in contrast to the fluorescence which exhibits a characteristic spectral change under the protolytic equilibrium A- + H+ = AH (pK = 4.805). The chemiluminescence is proposed to involve reaction of eaq with the anthranilo radical Ø(NH2)+COO-, formed by OH attack upon A- or AH. Deprotonation of Ø(NH2)+COO- occurs at pH > 7. Absolute yields of the x-ray induced emissions and absolute fluorescence quantum yields have been determined for the aminobenzoic acid isomers and for some related compounds.

IRRADIATION OF DIPHOSPHOPYRIDINE NUCLEOTIDE IN DILUTE AQUEOUS SOLUTIONS

1960 ◽  
Vol 38 (1) ◽  
pp. 1255-1263 ◽  
Author(s):  
D. K. Myers
Keyword(s):  
Absorption Spectrum ◽  
Aqueous Solutions ◽  
Ultraviolet Absorption ◽  
Ultraviolet Absorption Spectrum ◽  
Ph Values ◽  
In Vivo Experiments ◽  
X Irradiation ◽  
Dilute Aqueous Solutions

In extension of previous in vivo experiments, the effects of X irradiation on DPN were studied in vitro. No correlation between the effects on the ultraviolet absorption spectrum and on the coenzyme function of DPN was evident after irradiation at different pH values. However, the loss of coenzyme function could be correlated with the destruction of ribose and of riboside linkages. Catalase did not provide greater protection than did other proteins. It was concluded that the observed loss of DPN from irradiated cells is not due to the radiosensitivity of the DPN molecule itself.

X-Irradiation of L -Malic Acid in Aqueous Solutions

1956 ◽  
Vol 5 (2) ◽  
pp. 134 ◽  
Author(s):  
F. K. Putney ◽  
A. W. Pratt
Keyword(s):  
Aqueous Solutions ◽  
Malic Acid ◽  
X Irradiation

Ultrathin frozen sections of yeast without aldehyde prefixation

1978 ◽  
Vol 36 (2) ◽  
pp. 58-59
Author(s):  
K. J. Böhm ◽  
a. E. Unger
Keyword(s):  
Aqueous Solutions ◽  
Biological Material ◽  
Yeast Cells ◽  
Frozen Sections ◽  
Good Preservation ◽  
Ultrathin Frozen Sections

During the last years it was shown that also by means of cryo-ultra-microtomy a good preservation of substructural details of biological material was possible. However the specimen generally was prefixed in these cases with aldehydes.Preparing ultrathin frozen sections of chemically non-prefixed material commonly was linked up to considerable technical and manual expense and the results were not always satisfying. Furthermore, it seems to be impossible to carry out cytochemical investigations by means of treating sections of unfixed biological material with aqueous solutions.We therefore tried to overcome these difficulties by preparing yeast cells (S. cerevisiae) in the following manner:

Electron Microscopic Examination of a Transplantable Rat Mammary Carcinoma

1968 ◽  
Vol 26 ◽  
pp. 20-21
Author(s):  
S. Shirahama ◽  
G. C. Engle ◽  
R. M. Dutcher
Keyword(s):  
Electron Microscope ◽  
Osmium Tetroxide ◽  
Electron Microscopic Examination ◽  
Undifferentiated Carcinoma ◽  
Uranyl Acetate ◽  
Sprague Dawley ◽  
Electron Microscopic ◽  
North West ◽  
X Irradiation ◽  
Tissue Specimens

A transplantable carcinoma was established in North West Sprague Dawley (NWSD) rats by use of X-irradiation by Engle and Spencer. The tumor was passaged through 63 generations over a period of 32 months. The original tumor, an adenocarcinoma, changed into an undifferentiated carcinoma following the 19th transplant. The tumor grew well in NWSD rats of either sex at various ages. It was invariably fatal, causing death of the host within 15 to 35 days following transplantation.Tumor, thymus, spleen, and plasma from 7 rats receiving transplants of tumor at 3 to 9 weeks of age were examined with an electron microscope at intervals of 8, 15, 22 and 30 days after transplantation. Four normal control rats of the same age were also examined. The tissues were fixed in glutaraldehyde, postfixed in osmium tetroxide and embedded in Epon. The plasma was separated from heparanized blood and processed as previously described for the tissue specimens. Sections were stained with uranyl acetate followed by lead citrate and examined with an RCA EMU-3G electron microscope.

The Response of Testis Cells to Low Dose X-Irradiation

1981 ◽  
Vol 39 ◽  
pp. 542-543
Author(s):  
D. E. Philpott ◽  
W. Sapp ◽  
C. Williams ◽  
Joann Stevenson ◽  
S. Black
Keyword(s):  
Electron Microscopy ◽  
Stem Cell ◽  
Light Microscopy ◽  
Dose Level ◽  
Cross Sections ◽  
Low Dose ◽  
Light And Electron Microscopy ◽  
Cellular Responses ◽  
Post Irradiation ◽  
X Irradiation

The response of spermatogonial cells to X-irradiation is well documented. It has been shown that there is a radiation resistent stem cell (As) which, after irradiation, replenishes the seminiferous epithelium. Most investigations in this area have dealt with radiation dosages of 100R or more. This study was undertaken to observe cellular responses at doses less than 100R of X-irradiation utilizing a system in which the tissue can be used for light and electron microscopy.Brown B6D2F1 mice aged 16 weeks were exposed to X-irradiation (225KeV; 15mA; filter 0.35 Cu; 50-60 R/min). Four mice were irradiated at each dose level between 1 and 100 rads. Testes were removed 3 days post-irradiation, fixed, and embedded. Sections were cut at 2 microns for light microscopy. After staining, surviving spermatogonia were identified and counted in tubule cross sections. The surviving fraction of spermatogonia compared to control, S/S0, was plotted against dose to give the curve shown in Fig. 1.

Eds Of Radioactive Particles By Self-Induced Fluorescence

1990 ◽  
Vol 48 (2) ◽  
pp. 238-239
Author(s):  
Gregory L. Finch ◽  
Richard G. Cuddihy
Keyword(s):  
Electron Beam Irradiation ◽  
Nuclear Reactor ◽  
X Rays ◽  
Reactor Accident ◽  
Internal Radiation ◽  
X Ray ◽  
External Sources ◽  
X Irradiation ◽  
Available Information ◽  
Individual Particles

The elemental composition of individual particles is commonly measured by using energydispersive spectroscopic microanalysis (EDS) of samples excited with electron beam irradiation. Similarly, several investigators have characterized particles by using external monochromatic X-irradiation rather than electrons. However, there is little available information describing measurements of particulate characteristic X rays produced not from external sources of radiation, but rather from internal radiation contained within the particle itself. Here, we describe the low-energy (< 20 KeV) characteristic X-ray spectra produced by internal radiation self-excitation of two general types of particulate samples; individual radioactive particles produced during the Chernobyl nuclear reactor accident and radioactive fused aluminosilicate particles (FAP). In addition, we compare these spectra with those generated by conventional EDS.Approximately thirty radioactive particle samples from the Chernobyl accident were on a sample of wood that was near the reactor when the accident occurred. Individual particles still on the wood were microdissected from the bulk matrix after bulk autoradiography.

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