Normal ventricular size and ventriculo-hemispheric ratio in infants upto 6 months of age by cranial ultrasonography.

Fifty cases each of preterm (greater than 34 weeks), full term and one month to six months age (400 total) were subjected to cranial ultrasonography for determination of ventricular size and ventriculohemispheric ratio. Ventricular size steadily increased from 4.64 +/- 1.84 mm in preterm to 10.72 +/- 2.92 mm in six months old infant. Ventriculohemispheric ratio increased from 0.12 +/- 0.052 in preterm to 0.17 +/- 0.056 in three months of age. Then steady level was maintained at 0.17 +/- 0.064 upto six months of age.

Characterization of temperature sensitive mutants of Japanese encephalitis virus isolated from persistently infected mammalian cells.

Four new temperature-sensitive (ts) mutants of Japanese encephalitis virus (JEV) isolated from porcine kidney cells persistently infected with JEV and seven previously isolated ts mutants were studied. Of the eight mutants tested, five mutants ts1, ts14, ts36, ts48 and ts71, were thermolabile. Analyses of virus induced intracellular polypeptides revealed that with majority of the ts mutants, when grown at restrictive temperature, the viral proteins were quantitatively affected. All the five ts mutants tested for mouse virulence showed attenuation in infant mice by the intracerebral route. Two ts mutants, ts36 and ts48, escaped neutralization with two anti-JEV envelope protein specific monoclonal antibodies, however, these escape mutants reacted efficiently with the same monoclonal antibodies in antigen capture ELISA.