Biomaterial Database

Reirradiation tolerance of the immature rat spinal cord. 1992

A C Ruifrok, and B J Kleiboer, and A J van der Kogel

Institute of Radiotherapy, University of Nijmegen, The Netherlands.

The dose dependence and time course of long-term recovery in the cervical spinal cord of 3-week-old rats was investigated, and compared with the recovery in adults rats. At intervals of 1 to 168 days after initial irradiation of the cervical spinal cord at the age of 3 weeks, reirradiation experiments were performed to test the pattern of long-term recovery in immature spinal cord. The single dose ED50 for white matter mediated paresis was about 21 Gy for 3-week-old as well as adult rats, although the latency to paresis development increased from about 90 days in 3-week-old rats to about 250 days in adult rats. The main long-term recovery was seen during the first month after the initial radiation treatment at 3 weeks. This is in contrast to long-term recovery in adult rats, in which the main recovery took place between 2 and 6 months after the first irradiation. Calculations according to the LQ model showed that the extra dose that can be given to the cervical spinal cord after a 1-6 months interval in the 3-week-old rats reaches a maximum of about 20% of the total biological effect resulting in paresis. In adult rats the extra dose that can be given to the cervical spinal cord after a 6 months interval represents about 40% of the total biological effect. These studies show that time course as well as extent of long-term recovery from radiation treatment not only depends on tissue and species, but also on age.

UI	MeSH Term	Description	Entries
D009333	Neck	The part of a human or animal body connecting the HEAD to the rest of the body.	Necks
D010243	Paralysis	A general term most often used to describe severe or complete loss of muscle strength due to motor system disease from the level of the cerebral cortex to the muscle fiber. This term may also occasionally refer to a loss of sensory function. (From Adams et al., Principles of Neurology, 6th ed, p45)	Palsy,Plegia,Todd Paralysis,Todd's Paralysis,Palsies,Paralyses,Paralysis, Todd,Paralysis, Todd's,Plegias,Todds Paralysis
D011833	Radiation Injuries, Experimental	Experimentally produced harmful effects of ionizing or non-ionizing RADIATION in CHORDATA animals.	Experimental Radiation Injuries,Injuries, Experimental Radiation,Experimental Radiation Injury,Radiation Injury, Experimental
D011836	Radiation Tolerance	The ability of some cells or tissues to survive lethal doses of IONIZING RADIATION. Tolerance depends on the species, cell type, and physical and chemical variables, including RADIATION-PROTECTIVE AGENTS and RADIATION-SENSITIZING AGENTS.	Radiation Sensitivity,Radiosensitivity,Sensitivity, Radiation,Tolerance, Radiation,Radiation Sensitivities,Radiation Tolerances,Radiosensitivities,Sensitivities, Radiation,Tolerances, Radiation
D011839	Radiation, Ionizing	ELECTROMAGNETIC RADIATION or particle radiation (high energy ELEMENTARY PARTICLES) capable of directly or indirectly producing IONS in its passage through matter. The wavelengths of ionizing electromagnetic radiation are equal to or smaller than those of short (far) ultraviolet radiation and include gamma and X-rays.	Ionizing Radiation,Ionizing Radiations,Radiations, Ionizing
D011919	Rats, Inbred Strains	Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.	August Rats,Inbred Rat Strains,Inbred Strain of Rat,Inbred Strain of Rats,Inbred Strains of Rats,Rat, Inbred Strain,August Rat,Inbred Rat Strain,Inbred Strain Rat,Inbred Strain Rats,Inbred Strains Rat,Inbred Strains Rats,Rat Inbred Strain,Rat Inbred Strains,Rat Strain, Inbred,Rat Strains, Inbred,Rat, August,Rat, Inbred Strains,Rats Inbred Strain,Rats Inbred Strains,Rats, August,Rats, Inbred Strain,Strain Rat, Inbred,Strain Rats, Inbred,Strain, Inbred Rat,Strains, Inbred Rat
D004307	Dose-Response Relationship, Radiation	The relationship between the dose of administered radiation and the response of the organism or tissue to the radiation.	Dose Response Relationship, Radiation,Dose-Response Relationships, Radiation,Radiation Dose-Response Relationship,Radiation Dose-Response Relationships,Relationship, Radiation Dose-Response,Relationships, Radiation Dose-Response
D005260	Female		Females
D005552	Forelimb	A front limb of a quadruped. (The Random House College Dictionary, 1980)	Forelimbs
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia