Cloak and DaggerAppreciate the role that poisons have played in political assassinations
Know the major classes of poisons which might be used for this purpose
Know the clinical manifestations of dioxin poisoning
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Case Report
A 50 y.o. W/M political reform candidate in Ukraine was in excellent health until Sept 6, 2004, when he developed a headache three hours after returning from a late night dinner with the chief and deputy chief of Ukraine’s security services.
He did not eat everything he was served and vomited on the way home
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Case Report
Over the next four days he began experiencing severe diffuse stomach pain, nausea and vomiting, and pain over the left scapula. He later developed a one-side paralysis of his facial nerve.
Presidential elections in Ukraine were scheduled for October 31 with a runoff election on November 21.
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Physical Exam
He was taken out of the country and admitted to a leading hospital in Vienna on September 10.
On admission he was weak and tachycardic. His skin was pale with bluish-red discoloration. He had subcutaneous swelling in the periumbilical area. Mucosa were pale and dry. Heart and lung exam were normal. Abdominal exam showed distention and increased resistance to palpation in the epigastic area. He had no lymphadenopathy.
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Laboratory Studies
Laboratory studies were remarkable for an elevated lipase, elevated GGT, elevated CRP, elevated fibrinogen, low serum iron, and ketonuria
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Diagnostic Studies
His CT of the abdomen showed an enlarged pancreas. Ultrasound of the abdomen showed diffuse enlargement of the liver.
He had a normal chest X-ray. CT of his chest showed a possible basal pleural effusion.
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Diagnostic Studies
Gastroscopy revealed a rash of ulcers in the stomach and reflux gastritis. Colonoscopy revealed proctocolitis.
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Initial Diagnoses
Reflux gastritis
Acute protococolitis
Pancreatitis
Atypical skin disease rash over the face and thorax suggestive of a viral exanthem
Paralysis of the facial nerve
Left sided otitis
Calls for Assistance
His treating physicians concluded that “The negative general and alimentary condition caused probably by a grave viral infection or, possibly by chemical substances not normally contained in food.”
His physicians issued an international appeal for medical assistance in the diagnosis and treatment of this mysterious illness
The candidate, despite being seriously ill, returned to campaigning
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Political Events
Oct 31: first round election: no candidate captures 50%
Nov 21: second round of elections: current Prime Minister claims victory
Dec 3: Supreme court rules results of second round invalid
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Differential Diagnosis
Are you aware of any medical syndrome that can cause ulceration of the gastrointestinal tract (stomach to colon), pancreatitis, liver disease, skin rash with facial swelling and disfigurement, and facial nerve paresis?
What chemical or biological agents (or combination of these agents) might produce these symptoms?
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Clues
Ulceration of stomach and colon suggests that agent most likely entered through oral route
If biologic agent, most likely one of proven pathogenicity (letting a modified organism into the wild would be incomprehensibly reckless)
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Clues
Lack of fever, immune response (other than increased CRP) may point more to a toxin, but a biological agent cannot be ruled out.
If agent given orally, it would need to have been indiscernible in food or drink
Agent selected would likely be highly potent
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Protein synthesis inhibitors
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Disfiguring Skin Lesions
The patient improved with intensive supportive care. His general and alimentary condition stabilized in both clinical and laboratory terms
Three weeks after onset, however, he began to develop a dusky, gray discoloration and “bumps and cysts” on his face
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Chloracne
In early December, a British toxicologist suggested that the skin lesions may be consistent with chloracne, based on photos of the candidate in the world press
Chloracne photo from: Exposure to chlorinated biphenyls, transformer fire, Chicago, IL Orris P, Worobec SM, Kahn G, Hryhorczuk D, Hessl S Lancet 1. (1986) 210-211.
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Chloracne is a type of acne produced by exposure to “dioxin-like” chemicals which include polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), and chlorinated napthalenes
Onset occurs within 6 weeks to 5 months following exposure
Comedones and cysts predominate
“Dioxin”
The term “dioxin” refers to a group of chemical compounds that share certain similar chemical structures and mode-of-action biological characteristics
30 dioxin-like chemicals exist and include certain CDDs, CDFs, and PCBs
Mixtures characterized as Toxicity Equivalents (TEQs) with 2,3,7,8 TCDD = 1
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Dioxin in Blood
On December 11 the patient’s physician held a press conference to announce that blood tests confirm high concentrations of dioxin
Measured in the lipid layer of blood using ICP-MS
Patient’s level was 100,000 pg/g blood fat (second highest ever seen in a human)
Background levels are about 10 pg/g
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Poisoned Legacy
Assassination by poisoning is part of the legacy of the security services of the former USSR
On Oct 12, 1957 SMERSH agent, Bohdan Stashynsky assassinated the Ukrainian émigré leader Dr. Lev Rebet in Munich using a cyanide gas pistol
In 1959 Stashynsky assassinated the Ukrainian émigré leader Stepan Bandera with the same type of cyanide gas pistol
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Poisoned Legacy
One of the most famous cases was the assassination of the Bulgarian dissident Georgi Markov in London in 1978
He was killed in London with the poison ricin while waiting at a bus stop
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Poisoned Legacy
The ricin was contained in a pellet which was injected into this thigh from a spring loaded umbrella
Widely believed that assassins were Bulgarian secret police and KGB
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CDDs are a family of 75 different congeners
They vary by number and position of chlorine atoms on rings
Most toxic is 2,3,7,8 tetrachlorodibenzo-p-dioxin
2,3,7,8 TCDD is a solid at room temperature
2,3,7,8 TCDD
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of 2,3,7,8 TCDD
In rhesus monkeys, the LD50 of 2,3,7,8 TCDD is 70 mcg/kg
Clinicopathologic signs include weight loss, blepharitis, acneiform eruptions, loss of fingernails and eyelashes, facial alopecia, anemia, neutropenia, lymphopenia, reduction in thymus, lesions of digestive tract, degranulation of cells in pancreas, decrease in cholesterol, increase in triglycerides
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Acute Toxicity in Animals
Mechanism of death in animals is a “wasting syndrome” where animals continue to lose body weight over several weeks
Patient’s dose is estimated to have been about 1 mg or 15-20 mcg/kg
This is about 25% of the LD50 in rhesus monkeys
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Different species vary widely in their susceptibility to dioxin poisoning
Most common clinical features:
Immune system suppression
Cancer
Acute Toxicity in Man
The only reported human cases of acute oral poisoning with 2,3,7,8 TCDD are two which occurred in Vienna in 1997 (Gesau et al. Environmental Health Perspectives (2001) 109:865-869 and Archives of Toxicology (2002) 76:316-325.
2,3,7,8-TCDD blood levels in these cases:
140,000 pg/g
26,000 pg/g
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Other features:
Mildly elevated blood lipids
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Both patients were treated with Olestra, a non-absorbable fat
Olestra allows dioxins to diffuse back from the blood to the gut, allowing elimination in the feces
Resulted in a 10 fold increase in fecal elimination of 2,3,7,8-TCDD
Increase in total body clearance of 10-15%
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How Do Dioxins Produce Their Toxic Effects?
Dioxins exert their toxic mechanisms of action by first combining with the aryl hydrocarbon (Ah) receptor
The binding affinity of different dioxins with the Ah receptor reflects their relative toxicity
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In presence of TCDD, forms an active heterodimer with aromatic hydrocarbon nuclear translocator (ARNT/HIF-1B) and induces (or suppresses) the transcription of numerous genes including P4501A1 (CYP1A1)
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Chloracne
Increased GGT
Increased triglyceride and decreased HDL
Increased blood glucose
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Is Dioxin a Human Carcinogen?
In 1997 the International Agency for Research on Cancer classified 2,3,7,8 TCDD as a Group 1 carcinogen based on:
limited evidence in humans
SMR=1.40 (95% CI:1.1-1.7)
Understanding of mechanism (AhR)
Down-regulation of Ah Receptor
If dioxin is toxic in the mcg/kg range and in acute poisoning appears to have an elimination half life of at least 1.5 years, then why isn’t it more lethal in humans?
Experimental studies indicate that, after a transient increase, cellular levels of AhR decrease following TCDD binding
In Seveso, Italy, 20 years after a large-scale environmental accident with dioxin, levels of AhR transcripts were decreased in exposed subjects and negatively correlated with current TCDD levels
Down-regulation tends to decrease the amount of receptor available for ligand binding and to attenuate the resulting biologic responses
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Political Aftermath
Dec 11: poison confirmed as pure 2,3,7,8 TCDD, the most potent of the dioxins
Dec 26: third round of elections
Jan 11: Central election commission declares reform candidate the winner
Jan 20: Supreme court upholds his victory
Criminal investigation for poisoners underway
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Questions?
Pause for discussion before proceeding to the following 3 multiple choice questions.
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What is the major clinical manifestation of poisoning with dioxins?
Paralysis
Hepatitis
Chloracne
Alopecia
Questions
2. What biologic samples are used to quantify a person’s exposure to dioxin?
Hair
Urine
Blood
Saliva
Skin
Questions
3. In order to produce its toxic effect, dioxin must first combine with what molecular target?
Cytochrome a3
End presentation and distribute activity survey.