ELISA for detecting dengue and Japanese encephalitis viral antigen in mosquitoes

An indirect ELISA has been developed for detecting two viruses in triturated, experimentally infected mosquitoes: dengue (DEN) in Aedes aegypti (L.) and Ae. albopictus (Skuse) and Japanese encephalitis (JE) viral antigen in Culex tritaeniorhynchus Giles. DEN antigen from four strains of the virus, representing each of the four serotypes, and JE antigen were captured with a polyclonal anti-flavivirus IgG and detected with a monoclonal antibody (4G2) that reacts with all flaviviruses. Minimum viral titres detectable by the flavivirus antigen-capture ELISA, measured as multiples of the dose infecting 50% of mosquitoes (MID50), were 10(6.4), 10(4.5), 10(6.3), 10(6.9) and < or = 10(6.9) MID50/ml for DEN 1, DEN 2, DEN 3, DEN 4 and JE, respectively. Pools of up to 100 larvae or adults of Ae. aegypti and Ae. albopictus did not reduce the sensitivity of the ELISA to DEN 1, 2, 3 or 4. The results indicate that the antigen-capture ELISA could readily screen for DEN antigen in individual and pooled mosquitoes.     

A rapid method for the determination of arsenic concentrations in urine at field locations

A colorimetric method for arsenic in urine utilizing a portable hood and requiring minimal laboratory facilities is described. Urine samples are combusted in a hot plate-oven with MgO and Mg(No3)2. Arsine is generated from the ashed product and passed into silver diethyldithio-carbamate in pyridine. Inorganic and organic arsenicals in urine at 0.03 ppm with 6% variation is detectable.     

Experience with fifty repeat procedures for myocardial revascularization

Fifty coronary reoperations were performed in 49 patients. The reasons for the operations were occluded or stenotic grafts in 23 patients, an inadequate first operation in 13, progression of coronary atherosclerosis in 3, and combinations of these reasons in 11. Mediastinal adhesions made the operations difficult and produced hazards. Six patients died from the operation. Seven surgical mishaps occurred, including damage to five functioning grafts from the previous operation and laceration of two ventricles. Nine patients had less than complete operations because angiographically demonstrated targets could not be found. Repeat angiography was performed on 9 of the surviving patients. Ten of the 14 new or revised grafts were found to be functioning. Although a repeat operation is more difficult technically and carries additional risks as compared with a first operation, the indications are thought to be the same for both first and secondary revascularization procedures. The increased risks of the repeat operations are compelling arguments to strive for complete revascularization at an initial operation in order to avoid the necessity of the second one.