ELISA for the detection of venoms from four medically important snakes of India.

A double antibody sandwich enzyme linked immunosorbent assay (ELISA) was developed to detect Echis carinatus venom in various organs (brain, heart, lungs, liver, spleen and kidneys) as well as tissue at the site of injection of mice, at various time intervals (1, 6, 12, 18, 24 h and 12 h intervals up to 72 h) after death. The assay could detect E. carinatus venom levels up to 2.5 ng/ml of tissue homogenate and the venom was detected up to 72 h after death. A highly sensitive and species-specific avidin-biotin microtitre ELISA was also developed to detect venoms of four medically important Indian snakes (Bungarus caeruleus, Naja naja, E. carinatus and Daboia russelli russelli) in autopsy specimens of human victims of snake bite. The assay could detect venom levels as low as 100 pg/ml of tissue homogenate. Venoms were detected in brain, heart, lungs, liver, spleen, kidneys, tissue at the bite area and postmortem blood. In all 12 human victim cadavers tested the culprit species were identified. As observed in mice, tissue at the site of bite area showed the highest concentration of venom and the brain showed the least. Moderate amounts of venoms were found in liver, spleen, kidneys, heart and lungs. Development of a simple, rapid and species-specific diagnostic kit based on this ELISA technique useful to clinicians is discussed.

Ehretianone, a novel quinonoid xanthene from Ehretia buxifolia with antisnake venom activity.

Ehretianone (1), a new quinonoid xanthene, together with known sterols, was isolated from a MeOH extract of the root bark of Ehretia buxifolia. The structure of ehretianone was elucidated as 7-hydroxy-9a alpha-(3-methylbut-2-enyl)-4a alpha,9 alpha-(2-methylprop-2-enyl)-4a, 9a-dihydro-1,4-dioxoxanthene on the basis of spectroscopic data and X-ray crystallographic analysis. The antisnake venom activity of ehretianone against Echis carinatus venom in mice is also reported.

Differential diagnosis of viral hepatitis based on hepatitis viral markers.

192 patients of acute viral hepatitis (AVH) from three different hospitals of Madras metropolitan area during November 1985 to January 1986 were investigated for serologic markers of hepatitis A virus (anti HAVIgM) and hepatitis B virus (HBsAg, HBeAg, anti HBcIgM and anti HBs) by Enzyme linked immunosorbent assay (ELISA). While the overall pattern of AVH in Madras as revealed from the study showed Hepatitis A to be 36.4%, Hepatitis B 34.4% and Non-A Non-B 29.1%, the pattern differed significantly when areawise categorisation was done. The major AVH type in Government General Hospital was Hepatitis B (48.9%). While it was hepatitis A (46.9%) in Government Stanley Hospital and Non-A Non-B (40.0%) in Military Hospital. Using anti HBcIgM marker of Hepatitis B Virus and anti HAVIgM it was possible to make out that 13.5% of the cases, currently suffering from hepatitis A were either HBV carriers (8.3%) or cases convalescing from a previous Hepatitis B attack (5.3%). Various combinations of HBV markers positivity were observed and their diagnostic significance inferred.