Evaluation of antidotal effects of adamantyl derivative Tamorf in soman poisoning.

The nerve agent soman, a powerful inhibitor of acetylcholinesterase (AChE; EC 3.1.1.7), causes an array of toxic effects in the central nervous system. Adamantyl tenocyclidine derivative Tamorf (1-[2-(2-thienyl)-2-adamantyl] morpholine), a compound with potential activity at the N-methyl-D-aspartate (NMDA) receptors and with neuroprotective properties, is effective against convulsions and brain lesions related to soman poisoning. The objective of this study was to evaluate the antidotal potency of Tamorf (2.5 mg kg(-1)), which was tested alone as a pretreatment or in combination with atropine (10.0 mg kg(-1)) as a therapy in rats poisoned with two different sub-lethal doses of soman (1/4 and 1/2 of LD50). The effect of Tamorf was compared with carbamate physostigmine (0.1 mg kg(-1)). The study also determined the possible genotoxic effects of Tamorf and physostigmine, especially primary DNA damage in white blood cells, liver and brain tissue. Tamorf administered 5 min before poisoning stopped soman-induced seizures, was successful against sub-lethal doses of soman and protected AChE activity in the brain (P = 0.0014, P = 0.0019), and in plasma (P = 0.0464, P = 0.0405). Compared with Tamorf, physostigmine was slightly effective in the elimination of soman-induced poisoning in rats. The pharmacological effect of Tamorf and atropine was less effective as therapy, but did not increase soman toxicity (P > 0.05 for all interactions). The results obtained indicate that Tamorf and physostigmine are not genotoxic to rats in the concentrations tested. Treatment with Tamorf seems to be a good alternative for current pretreatment in soman poisoning. Its antidotal mechanism is complex and is based on combined biochemical and receptor properties.

Seed-borne fungi and ochratoxin A contamination of dry beans (Phaseolus vulgaris L.) in the Republic of Croatia.

The study was designed to identify seed-borne fungi on bean (Phaseolus vulgaris L.) crops grown in 13 counties of the Republic of Croatia and their association with ochratoxin A (OTA) production. Bean samples (N=45) were collected in Croatia in 2001 shortly after the harvest and were stored at -20 degrees C for mycological and mycotoxin analyses. The most common fungi isolated were Cladosporium spp. (98%) Alternaria spp. (75%), Aspergillus spp. (73%), Rhizopus spp. (73%), Penicillium spp. (69%), Fusarium spp. (38%), Botrytis spp. (27%), Trichothecium spp. (24%), and Chaetomium spp. (18%). OTA was found only in samples contaminated with Penicillium and Aspergillus spp. Using HPLC (detection limit 0.25 microg/kg), OTA was found in 17 out of 45 samples (38%), and the mean concentration in positive samples was 0.41+/-0.21 microg OTA/kg. Beans from south Croatia (Adriatic coast) were OTA-free and the least mould-infected, while the mean OTA concentration and mould infection of samples from other regions were similar. The OTA contamination of beans in our country is low. Although beans are not severely contaminated with OTA, their consumption may contribute to the exposure to OTA from other commodities.