[The interferon reaction of the leukocytes in newborn infants and their mothers].

The interferon reaction of leucocytes (IRL) in the newborns and their mothers were examined in vitro. The ability of leucocytes, obtained from the blood of the umbilical cord of newborns, to synthesize interferon was established in 48.78% of the investigated newborns while in their mothers the relative part was 70.

[Typing of Newcastle virus isolates by mean death time of chickens in the cloacal test].

The mean death time in a cloacal test (MDT/CT) was employed to define the pathogenic type of isolates of the Newcastle Disease virus (NDV) with 5-week-old birds. The results were compared with the use of standard methods for typing--the mean death time with 10-day-old chick embryos as defined by the minimal lethal dose (MDT/MLD), the intracerebral pathogenic index for day-old chicks (ICPI), the intravenous pathogenic index for 6-8-weak-old birds (IVPI). Sixteen local isolates and 6 reference strains of NDV were used in the experiments.