Nitric oxide metabolites in the urine of full-term and preterm infants.

BACKGROUND

In newborn full-term and preterm infants the urine nitrites and nitrates (NOx) were measured, in order to investigate the effects of different pathological conditions (infection, hypoxia) on systemic nitric oxide production.

METHODS

Urine nitrites and nitrates were determined by means of the Griess reaction, after reduction of nitrates to nitrites with nitrate reductase.

RESULTS

The NOx level was higher in preterm (278 nmol/mL) than full-term (176 nmol/mL) infants. Low NOx (115 nmol/mL) levels accompanied generalized infections, while its high contents (650 nmol/mL) was found in cytomegalovirus and one case of Pneumocystis carinii infection. Moderate increase of NOx production was observed in infants with local pulmonary infections and encephalopathies.

CONCLUSIONS

The results indicate urinary NOx level is lowered in infants with life-threatening generalized infection. A possibility of a rapid test based on newborn urinary NOx level determination is considered.