Radiation injury

MetaHoelement complexes may be useful for the post-irradiation treatment of radiation injury, based on the observation that several of these compounds accelerate recovery of, among other things, lympho/hemopoiesis. Preirradiation Mn2(0)(DIPS)g increases the survival of y-irradiated mice (103). Treatment of mice that have been exposed to an LD q q dose of y-rays plus Mn2(0)(DIPS)g either 1 or 3 h after irradiation also increases survival, which supports the hypothesis that this compound is an effective radiorecovery agent (105). Again, this increase in survival may result from the resynthesis of radiation-depleted Mn-dependent enzymes that facHitate the recovery of immunocompetence and tissue repair, as reported for Cu(II)2(DIPS)4. 

Pentoxifylline is stmcturaHy related to other methylxanthine derivatives such as caffeine [58-02-2] (1,3,7-trimethylxanthine), theobromine [83-67-0] (3,7-dimethylxanthine), and theophylline [58-55-9] (3,7-dihydro-1,3-dimethyl-1 H-piirine-2,6-dione or 1,3-dimethylxanthine), which also show radioprotective activity in some instances, suggesting that methylxanthines as a dmg class may radioprotect through a common mechanism (see Alkaloids). In a retrospective analysis of cervical and endometrial cancer patients receiving primary or adjuvant XRT, no association between caffeine consumption and incidence of acute radiation effects has been found. However, there was a decreased incidence of severe late radiation injury in cervical cancer patients who consumed higher levels of caffeine at the time of thek XRT (121). The observed lack of correlation between caffeine consumption and acute radiation effects is consistent with laboratory investigations using pentoxifylline. 

Chinese Herbal Medicines. Many traditional Chinese medicines have been screened for radioprotective activity in experimental animals. In one study of more than a thousand Chinese herbs, a number of agents increased the survival rate of dogs exposed to a lethal dose of y-rays by 30—40%, and some symptoms of radiation injury were ameHorated. These effects are potentially related to stimulation of the hemopoietic and immune systems (130). Extracts of five Chinese dmg plants, as weU as aspirin, effectively protected mice exposed to 7.5—8.0 Gy (750—800 rad) of y-radiation, and increased survival rates by 8—50% (131). Several Chinese traditional medicines, adininistered ip before or after irradiation, protected against Hpid peroxidation in a variety of mouse tissues, including BM, Hver, and spleen, as weU as in mouse Hver microsomal suspensions irradiated in vitro (132). 

Glutamine has been widely examined as a potential agent for enhancing intestinal repair foUowing radiation injury, although its value in this regard remains to be clearly estabHshed (144). Glutamine does exert radioprotective effects in cultured CHO ceUs. 

PGE andDenvatives. PGE2 and several related PGs protect against radiation injury in the rodent intestine with respect to both crypt clonogen survival and LD Q g Protection of hemopoietic tissue has also been reported using the exogenous CEU-S assay (215), and 40 p.m of 16,16-dimethyl PGE2... 

J. Lavei and co-workeis. Treatment of Radiation Injuries, Plenum Press, New York, 1990. 

Strel tsova, V. N. and Moskalev, Yu.I. (1961). Radiation Injury Caused by Cerium-144 in Dogs, Rabbits, Rats, and Mice, Report No. LF-tr-79 (National Technical Information Service, Springfield, Virginia). 

Sullivan, M. F. (1966). Sodium, water and Bk absorption in irradiated rats Influence of bile, page 216 in Gastrointestinal Radiation Injury (Excerpta Medica Foundation, Amsterdam). 

Radiation Injury. Late radiation enteropathy is associated with alterations of small intestinal motility [154], intestinal pseudoobstruction [154, 155] and Gram-negative colonization of the small bowel in patients with impaired small bowel motility [12], In patients with severe injury, alterations in the motility and microflora are of main importance for the clinical symptoms [154],... 

The exclusion method also includes instances in which drug candidates are themselves excluded from causation status because a nondrug etiology is clearly demonstrable (environmental or occupational factors, radiation injury, the underlying disease of the patient, or a comorbid state) that can reasonably account for the clinicopathology findings. 

Brown, D., Weiss, J.G., Macvittie, T.J., and Pillai, M.V., Treatment of Radiation Injuries, Plenum Press, New York, 1989. 

Aging (skin and other tissues), myocardial infarct or stroke, inflammation, rheumatoid arthritis, atherosclerosis, pulmonary disorders (asthma and chronic obstructive pulmonary diseases), radiation injury, organ transplant rejection, psoriasis, hypertension, AIDS, multiple types of cancer, neuro-degenerative diseases (Parkinson s), diabetes, muscular dystrophy... 

This has led to a growing awareness of mechanisms by which tumors and normal tissue are able to overcome damage from radiation injury. This knowledge has resulted in a vast amount of preclinical study of ways that these molecular abnormalities may be specifically targeted to result in clinical benefit, not only by potentially impacting on systemic disease, but by enhancing radiosensitivity. The last part of this book describes some of these agents and pathways. 

Grampa G. 1971. Radiation injury with particular reference to Thorotrast. Pathol Ann 6 147-169. 

Antiradiation. An agent capable of counteracting the effects of radiation effective against radiation injury. 

Other causes of gastric atrophy, such as those due to Helicobacter pylori,AIDS, or radiation injury, can lead to a similar outcome but from different pathogenic mechanisms. Therefore, vitamin B12 deficiency, resulting in neurological, psychiatric, metabolic, and hematological disorders, can arise from any one of the many causes listed in Table 28-1. For this reason, the term pernicious anemia (PA) is used here to describe only the classical disease that is associated with IF deficiency due to autoimmune gastritis. 

The physical appearance of radiation burns and thermal burns is the same. The difference lies not only in their etiology, but in the time it takes for the wound to appear. Thermal injury is often visible instantaneously or appears soon after a person is burned. Radiation injury can take days to weeks to appear, depending on the dose. A visible injury is an indication of a high localized dose of radiation and the wound must be decontaminated as in chemical injury. This localized radiation exposure can result in various changes to the skin, depending on the dose. Although the patient s wound may be contaminated, the patient and the wound are not radioactive. 

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