phalloidine and Syndrome

Actin, one of the major filamentous cytoskeletal molecules, is involved in a variety of cellular functions. Whereas an association between muscle actin mutations and skeletal and cardiac myopathies has been well documented, reports of human disease arising from mutations of nonmuscle actin genes have been rare. We have identified a missense point mutation in the gene coding for beta -actin that results in an arginine-to-tryptophan substitution at position 183. The disease phenotype includes developmental midline malformations, sensory hearing loss, and a delayed-onset generalized dystonia syndrome in monozygotic twins. Cellular studies of a lymphoblastoid cell line obtained from an affected patient demonstrated morphological abnormalities of the actin cytoskeleton and altered actin depolymerization dynamics in response to latrunculin A, an actin monomer-sequestering drug. Resistance to latrunculin A was also observed in NIH 3T3 cells expressing the mutant actin. These findings suggest that mutations in nonmuscle actins may be associated with a broad spectrum of developmental malformations and/or neurological abnormalities such as dystonia.

Topics: Actins; Amino Acid Sequence; Amino Acid Substitution; Animals; Bridged Bicyclo Compounds, Heterocyclic; Deafness; Drug Resistance; Dystonia; Hearing Loss, Sensorineural; Humans; Male; Mice; Microsatellite Repeats; Molecular Sequence Data; Mutation, Missense; Nervous System Malformations; NIH 3T3 Cells; Phalloidine; Stress Fibers; Syndrome; Thiazoles; Thiazolidines; Transfection; Twins, Monozygotic

After consumption of mushrooms containing amatoxins (Amanita, Lepiota, and Galerina species), symptoms usually develop after a long delay (>6 h). Initial symptoms start as severe gastroenteritis, progressing to liver failure and possibly death as a result of hepatic coma. Since the survival rate of poisoned patients is claimed to depend on the time of beginning of efficient treatment, fast and reliable assays for amatoxins in biological fluids are essential. Described analytical methods for amatoxins include high performance liquid chromatography and radioimmunoassay (RIA). Recently, a new enzyme-linked immunosorbent assay (Bühlmann Amanitin ELISA kit) has been introduced as an alternative method to RIA. This ELISA-based assay offers several advantages: no complex extraction procedure is required (vs. HPLC) and no safety precautions concerning radioactivity have to be taken (vs. RIA). From August 2004 to October 2005, a pilot study was performed to test the practicability and the clinical utility of this method in emergency situations.. ten urines, 9 serums and 1 faeces from 10 patients suffering from acute gastroenteritis after mushroom ingestions (7 contaminated meals) were analyzed. Definitive diagnosis of amatoxin poisoning was made in 4 cases (3 contaminated meals) on the basis of the anamnesis, laboratory results, and clinical course. A patient developed a severe amatoxin poisoning with urinary amanitins level < 1.5 microg/L (urines were collected more than 72 h after mushroom ingestion). Two patients were paucisymptomatic with urinary amanitins levels >10 microg/L (urines were collected before the 36th hour).. Urine is the sample of choice for the determination of amatoxins. The most critical factor to invalidate the usefulness of this analysis is time. After 36 h, the sensitivity is unreliable.

Topics: Amanitins; Enzyme-Linked Immunosorbent Assay; Female; Humans; Male; Mushroom Poisoning; Phalloidine; Syndrome