Radiographic assessment of pulmonary fluid clearance and lung aeration in newborn calves delivered by elective Caesarean section.

The aim of this study was to develop a radiographic standard for the assessment of pulmonary fluid clearance and lung aeration in newborn calves. Caesarean-delivered mature calves (n = 9) underwent lung assessment by thoracic radiography as well as arterial and venous blood gas analysis within the first 30 min, 1, 2, 3, 6, 12 and 24 hr after birth. The results indicated that newborn calves delivered by elective Caesarean section suffered from a physiological combined respiratory and metabolic acidosis with the dominance of respiratory acidosis, and an improvement in these conditions was recorded within 24 hr after birth.

Isolation and characterization of a methylammonium resistant mutant of Neurospora crassa.

A mutant of Neurospora crassa has been isolated which is resistant to methylammonium, a structural analog of ammonium. In contrast to wild type, this mutant, mea-1, has derepressed nitrate reductase and nitrite reductase activities in the presence of ammonium. However, glutamine still represses these nitrate assimilation enzymes in mea-1.