SUMMARY Transcutaneous Po2, heart rate, and aortic blood pressure were measured in 10 mechanically-ventilated newborn infants to assess the degree and course of hypoxaemia, and to monitor the cardiovascular and respiratory changes during tracheal toilet. Five infants weighed < 1250 (mean 994) g, and 5 infants weighed >1750 (mean 2216) g. During tracheal suction the TcPo2 fell from 68 ± 27 (x ± SD) to 43 ± 23 mmHg, and the heart rate from 144 ± 8 to 123 ± 25 beats/minute, but the blood pressure increased from 44 ± 24 to 49 ± 24 mmHg. Hypoxaemia (TcPo2 <50 mmHg) occurred in 7 of 8 initially well-oxygenated infants when suctioned. The decrease in TcPo2 was similar for both groups of infants. It was greater in infants with controlled ventilation and an F0o2 >0.8 than in infants with intermittent mandatory ventilation and an F1o2 <0X8. The TcPo2 fall correlated well with the TcPo2 during the control period but not during the time that the infants were disconnected from the respirator. A critical re-evaluation of routine tracheal toilet is needed.

The compliance of the respiratory system was determined at an average of 2.89 h (range 45 min – 8 h) after birth in 82 newborns who were retrospectively divided into group 1: healthy newborns (mean gestational age 37.1 weeks, range 30–41 weeks); group 2: newborns with respiratory distress (RD) needing no ventilatory support (mean gestational age 37.3 weeks, range 35–40 weeks); group 3: newborns with RD needing ventilatory support and surviving (mean gestational age 34.3 weeks, range 30 – 39 weeks), and group 4: newborns with RD who needed ventilatory support and died (mean gestational age 30’.8 weeks, range 28 – 37 weeks). Respiratory compliance was measured by the airway occlusion technique in spontaneously breathing babies and by injecting a known volume of gas into the closed airway system and measuring airway pressure in intubated babies. The difference in postnatal compliance was statistically significant (p < 0.01) in those four groups and was correlated with the severity of the disease in groups 2 and 3. In infants with RD, compliance was highly predictive for the need for ventilatory support (93% correct and 7% erroneous) and in infants with ventilatory support, for the mortality (83% correct and 17% erroneous). We conclude that postnatal compliance measurements are very useful to predict the course and outcome as well as to classify the severity of RD.

Immunoelectrophoresis of glomerular basement membrane antigens in the urine of 20 Type 1 (insulin-dependent) diabetic and 10 healthy children was performed. In 10 of the diabetic children, there was altered alpha-1-mobility, while the other diabetic and normal children showed alpha-2-mobility. After incubation with glucose, glomerular basement membrane antigens in the urine of healthy children showed alpha-1-mobility. Isolated human kidney glomerular basement membrane split products obtained by proteolytic degradation (papain, trypsin, chymotrypsin) were also investigated by immunoelectrophoresis. A difference was observed in the immunoelectrophoretic pattern of native and glycosylated glomerular basement membrane split products. A distinct increase of thiobarbituric acid assay positive glomerular basement membrane structures after incubation with glucose provides suggestive evidence for the occurrence of non-enzymatic glycosylation of glomerular basement membrane proteins. Glycosylated glomerular basement membrane proteins may contribute to both functional and morphological changes in diabetic glomerulosclerosis.