Cyclosarin-An Organophosphate Nerve Agent

Organophosphorus compounds ascribed to as nerve agents (sarin, soman, tabun, cyclosarin) are highly toxic, and are considered to be the most dangerous chemical compounds. All apparently share a common mechanism of cholinesterase inhibition and can cause similar sv.m .ot oms. The standard therapy, in the case of organophosphorus poisoning, has the prophylactic use of reversibly acting AChE inhibitors and antidotal administration of AChE reactivators-oximes. Unfortunately, none of these oximes can be regarded as a broad spectrum antidote, ie, effective against all nerve agents. While the presently available oximes (pralidoxime, ohidoxime) are not considered to be sufficiently effective against nerve agents, especially in the case of soman poisoning, the H oximes (HI-6, HLo7) appear to,be very promising antidotes against nerve agents because these are able to protect the experimental animals from toxic effects and improve survival of animals poisoned with supralethal doses. A lot of research has been pursued on the treatment of sarin, soman, and tabun, but cyclosarin was not considered for such a study for a long time. Recently, attention of researchers has also turned to cyclosarin because of its potential use as a chemical warfare agent. Cyclosarin is highly toxic organophosphorus compound which is resistant to conventional oxime therapy. This paper reviews the latest positionof cyclosarin in standpoint of medical treatment by various reactivators considering the ability of various oximes, HI-6, HS-6, BI-6, and KO33 of their reactivation potency

Determination of minimum effective doses of luteinizing hormone and human chorionic gonadotropin for intrafollicular treatment to induce ovulation in dairy heifers.

peer reviewedThe aim of this study was to determine the minimum effective intrafollicular doses of luteinizing hormone and human chorionic gonadotropin in order to induce ovulation in cycling dairy heifers that have not yet been adequately established. Application of 10, 5, 1, 0.5, 0.1, 0.01 and 0.001 µg luteinizing hormone as well as 10, 1, 0.1, 0.01 and 0.001 international units (IU) of human chorionic gonadotropin in dominant follicles was performed on day 7 of the oestrous cycle. Control animals were given luteinizing hormone (12.5 mg and 25 mg) or human chorionic gonadotropin (2000 IU) intravenously. Accessory corpus luteum on day 14 of the oestrous cycle was considered as an evidence of ovulation. Ovulation was observed in 2 out of 3 heifers in each treatment group (n = 3) after administration of 10–0.1 µg luteinizing hormone (except for 0.5 µg – ovulation in 3 of 3 heifers), in all heifers after administration of 10–0.01 IU human chorionic gonadotropin as well as in all control heifers. Administration of 0.01 µg and 0.001 µg luteinizing hormone as well as of 0.001 IU human chorionic gonadotropin did not result in ovulation. Higher progesterone concentration on day 14 vs. day 7 of the oestrous cycle was found after all treatments. Nevertheless, the differences were signicant (P < 0.05) only after intrafollicular treatments with 5, 1 and 0.001 µg luteinizing hormone as well as 10, 1 and 0.01 IU human chorionic gonadotropin. In conclusion, minimum efcient doses for intrafollicular treatment of the dominant follicles in cycling heifers capable of inducing ovulation were 0.1 µg of luteinizing hormone and 0.01 IU of human chorionic gonadotropin. This is the rst study describing the intrafollicular luteinizing hormone administration in cycling dairy heifers