Ricin injection

A third case of intramuscular ricin injection involved a 53 year-old male who injected part of 13 chewed castor beans into his thigh with suicidal intent (Passeron et al., 2004). He developed necrotic cellulitis complicated by Enterococcus faecalis infection requiring emergency surgical debridement, but recovered after three months hospitalization. 

Many of the results for ricin injection derive from rodent studies. The highest concentration of ricin was foimd to localize to the spleen after either intravenous or intraperitoneal administration of I-ricin, whereas... 

Ricin would probably be aerosolized, but it could also be used by an assassin who might prepare it for ingestion or injection. Ricin is not nearly as potent as the C. botulinum toxin, and thus would have to be produced in very large quantities for large-scale use. 

The initial symptoms of ricin poisoning are gastroenteritis, in which there is bleeding, followed by arrythmias of the heart, depression of the central nervous system, coma, and then death. The toxin is especially potent when injected, whereas a single castor bean can be eaten without... 

Several cases of ricin exposure via parenteral routes were documented. A 20-year-old man was admitted to the hospital 36 h after subcutaneously injecting castor bean extract. Symptoms were characteristic of nausea, weakness, dizziness, and myalgias. He developed anuria and hypotension, followed by hepatorenal and cardiorespiratory failure, and died 18 h following admission. In another report, a 36-year-old chemist extracted ricin from a castor... 

Fodstad, O., Olsnes, S., Pihl, A. (1976). Toxicity, distribution and elimination of the cancerostatic lectins abrin and ricin after parenteral injection into mice. Br. J. Cancer 34 418-25. Fodstad, O., Johannessen, J.V., Schjerven, L., Pihl, A. (1979). Toxicity of abrin and ricin in mice and dogs. J. Toxicol. Environ. Health 5 1073-84. 

The metabolism and elimination of toxalbumins is poorly understood. Ricin is eliminated by first order kinetics when injected IV into mice and human cancer patients (Godal et al, 1984). The plasma half-life in humans is about 2 days (Kopferschmitt, 1983). 

Injection of botulinum into the muscle produces maximal paralysis at approximately 5 to 7 days and lasts for up to several months.This paralysis allows the injected muscle to stretch as its antagonist contracts. More recently, the use of the immunotoxin Ricin-mAb35 has been recommended as a possible alternative to botulinum because of its longer duration of action. However, additional studies are needed before widespread use in humans. 

Christiansen SP, Becker BA, laizzo PA, et al. Extraocular muscle force generation after Ricin-mAb35 injection implications for strabismus treatment. JAAPOS 2003 7 1-6. 

Transdermal exposure to ricin is not serious, since it is not well absorbed through the skin. Oral exposure, for example by ingestion of castor beans, can cause severe gastroenteritis, gastrointestinal hemorrhage, and death due to circulatory collapse. Parenteral injection of ricin is rapidly fatal, as is aerosol exposure the lethal dose by these routes is 5-10 micrograms/kg (8). 

Injected ricin kills laboratory animals in a concentration- and time-dependent manner with steep lethality curves (Fodstad et al., 1976, 1979 Olsnes and Pihl, 1977). After administration of ricin to experimental animals by injection, there is a characteristic time delay before signs of intoxication appear. The delay time decreases with increasing amounts of toxin, but it is always several hours, perhaps reflecting the time required for sufficient toxin to reach the target ribosome and disrupt protein synthesis (Olsnes and Pihl, 1977 Fodstad et al., 1979). In laboratory rats, for example, liver protein biosynthesis is unchanged compared with control levels for the first 3 h after injection (i.p.) with 500 pg/kg ricin, but steadily declines to approximately 15% of that of control groups by 10 h (Lin et al., 1971). 

The first signs of ricin intoxication in laboratory animals are typically lethargy and refusal to eat, followed later by a rapid drop in body temperature with characteristic shivering, and, ultimately, hypotension death is usually delayed until 10 h to 5 days after exposure, depending on the amount of toxin injected and the species of animal (Flexner, 1897 Waller et al., 1966 Balint, 1974 Fodstad et al., 1979). Laboratory animals surviving the first 6-7 days after injection of sublethal doses of... 

Animal Lethal Dose of Ingested Castor Seed (g/kg) Lethal Dose of Injected (i.m.) Ricin (p.g/kg) Lethal Dose of Injected (i.p. or i.v.) Ricin (pig/kg) Relative Resistance to Injected (s.c.) Ricin ... 

Relative resistance to injected ricin (s.c.) estimated by comparing the minimum fatal and maximum nonfatal doses and considering the time to death (Hunt et al., 1918). A larger number indicates relatively greater resistance to ricin tabulated values are normalized by assigning 100 arbitrarily to the laboratory mouse. 

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