Tumour Induction in Experimental Animals after Neutron and X-Irradiation

1986 ◽  
pp. 27-50
Author(s):  
J. J. Broerse
Keyword(s):  
Experimental Animals ◽  
Tumour Induction ◽  
X Irradiation

Investigation of Lung Tumour Induction in BALB/cJ Mice Following Paternal X-irradiation

1995 ◽  
Vol 67 (5) ◽  
pp. 607-615 ◽  
Author(s):  
B.M. Cattanach ◽  
G. Patrick ◽  
D. Papworth ◽  
D.T. Goodhead ◽  
T. Hacker ◽  
...  
Keyword(s):  
Lung Tumour ◽  
Tumour Induction ◽  
X Irradiation

Investigation of lung tumour induction in C3HHeH mice, with and without tumour promotion with urethane, following paternal X-irradiation

1998 ◽  
Vol 403 (1-2) ◽  
pp. 1-12 ◽  
Author(s):  
B.M. Cattanach ◽  
D. Papworth ◽  
G. Patrick ◽  
D.T. Goodhead ◽  
T. Hacker ◽  
...  
Keyword(s):  
Lung Tumour ◽  
Tumour Induction ◽  
Tumour Promotion ◽  
X Irradiation

Effects of whole-body x-irradiation on electroshock seizure responses in developing rats

1963 ◽  
Vol 205 (1) ◽  
pp. 177-180 ◽  
Author(s):  
Antonia Vernadakis ◽  
Paola S. Timiras
Keyword(s):  
Neuronal Activity ◽  
Brain Stimulation ◽  
Hind Limb ◽  
Brain Activity ◽  
Whole Body ◽  
Experimental Animals ◽  
X Irradiation ◽  
Limb Flexion ◽  
The Brain

Electroshock seizure responses were studied in control and irradiated rats between 8 and 55 days of age. Experimental animals were exposed to 500 r whole-body X-irradiation 2 days postnatally. In maturing rats seizure patterns produced by brain stimulation with 50 ma current appear in sequence: hyperkinesia, clonus, forelimb flexion, forelimb extension followed by hind limb flexion, and hind limb flexion followed by hind limb extension. In irradiated rats full flexor-extensor seizure pattern appeared in 50% of animals at 13 days of age, 3 days earlier than in controls. Extension was longer and flexion, clonus, and total seizure were shorter in irradiated than in controls. In both groups durations of clonus and total seizure were related inversely to durations of extension. Duration of flexion decreased and duration of extension increased up to 22nd day of age in all animals. This indicates increased neuronal activity as the brain matures. Also thresholds for minimal electroshock convulsions decreased up to 22nd day of age, further indicating increased brain activity with maturation. Thresholds were significantly lower in irradiated rats than in controls.

scholarly journals The Effect of X-Irradiation on 5-Hydroxytryptamine (Serotonin) Contents in the Small Intestines of Experimental Animals

1962 ◽  
Vol 3 (2) ◽  
pp. 104-108 ◽  
Author(s):  
Osamu MATSUOKA ◽  
Takehiko TSUCHIYA ◽  
Yoshinori FURUKAWA
Keyword(s):  
Experimental Animals ◽  
X Irradiation ◽  
Small Intestines

Environmental Effects on the Embryos and Fetuses of Experimental Animals

PEDIATRICS ◽  
1974 ◽  
Vol 53 (5) ◽  
pp. 821-822
Author(s):  
Robert L. Brent
Keyword(s):  
Congenital Malformations ◽  
Experimental Animals ◽  
Fetal Period ◽  
Gestational Period ◽  
The Past ◽  
Environmental Agents ◽  
X Irradiation ◽  
High Doses ◽  
The Brain ◽  
Period Of Gestation

In examining the offspring of experimental animals or man in relation to exposures to environmental agents, account should be taken of certain principles developed over the past five decades. TERATOGENESIS Before the Period of Implantation Experimental embryologic studies have shown that before implantation there is a so-called omnipotential period of development, when all cells have the ability to form a complete embryo. During this interval it is difficult, if not impossible, to induce congenital malformations. This interval extends to 6½ days in the mouse, 8 days in the rat, and about 12 to 13 days in man. Teratogenic Period The interval during which teratogenesis may be induced in man is short relative to the total gestational period, in contrast to the period of susceptibility in the mouse or rat, in which it is about one third of the gestational period. Fetal Period Subsequently, classical teratogens do not produce gross malformations that are easily observable at birth. Exposures to hazardous agents may still produce other effects throughout the later period of gestation, namely, cell deletions or tissue hypoplasia. This is a new area about which we do not yet understand very much, even with respect to high doses. When the mouse embryo is exposed late in gestation to 200 rad, a marked depletion has been observed in the cerebral cortex. This easily visible difference from normal upon inspection of the brain has little effect on behavior. In the same way, x-irradiation of the mouse testes produced hypoplasia, but no defect in morphogenesis.

Analytical Electron Microscopy (AEM) of Meningeal Cells Exposed to Particulate Cobalt During Studies of Experimental Epilepsy

1982 ◽  
Vol 40 ◽  
pp. 186-187
Author(s):  
R.G. Frederickson ◽  
R.G. Ulrich ◽  
J.L. Culberson
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Experimental Epilepsy ◽  
Metallic Cobalt ◽  
Experimental Animals ◽  
X Ray ◽  
Brain Surface ◽  
Meningeal Cells ◽  
Analytical Electron ◽  
The Brain

Metallic cobalt acts as an epileptogenic agent when placed on the brain surface of some experimental animals. The mechanism by which this substance produces abnormal neuronal discharge is unknown. One potentially useful approach to this problem is to study the cellular and extracellular distribution of elemental cobalt in the meninges and adjacent cerebral cortex. Since it is possible to demonstrate the morphological localization and distribution of heavy metals, such as cobalt, by correlative x-ray analysis and electron microscopy (i.e., by AEM), we are using AEM to locate and identify elemental cobalt in phagocytic meningeal cells of young 80-day postnatal opossums following a subdural injection of cobalt particles.

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.

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