2-4-dinitrophenylhydrazine and Chronic-Disease

To develop a method capable of quantifying the oxidative modification of proteins in pulmonary fluid obtained during routine suctioning of neonates receiving ventilation, thus providing an integrated assessment of antioxidant defenses.. Consecutive sample of neonates receiving ventilation.. Neonatal intensive care unit.. Twenty-six neonates receiving ventilation with a gestational age of 24 to 42 weeks, from whom 246 samples were collected and analyzed.. The carbonyl content in the lavage samples was measured by reaction with 2,4-dinitrophenylhydrazine followed by high-pressure liquid chromatography. Oxidation of proteins caused introduction of carbonyl groups into the side chains of the protein, providing a convenient and relatively specific marker of oxidative damage. On the first day of life, the initial protein-bound carbonyl for each neonate was usually low and consequently was not significantly related to birth weight, gestational age, or initial ventilatory requirements. Examination of the changes in pulmonary protein carbonyl in the first days of life revealed correlations of interest. In the first day of life, four neonates whose average inspired oxygen were < 40% showed no increase in carbonyl content, whereas four neonates whose inspired oxygen was > 40% showed an average increase in carbonyl of 51% (P < .001). Also, the need for ventilation > 3 days was correlated with elevated carbonyl in those first 3 days. The carbonyl content averaged over the first 3 days was 0.13 +/- 0.02 mol carbonyl/mol protein for the eight neonates receiving ventilation < 72 hours, whereas the nine needing longer ventilation had a carbonyl content of 0.28 +/- 0.03 mol carbonyl/mol protein (P < .05). Seven neonates were treated with dexamethasone because of ventilator dependence at 14 days of age. In these neonates, treatment was associated with a 50% reduction in carbonyl content within 48 hours (P < .02).. Oxidative damage to pulmonary proteins can be quantitated in samples obtained during routine suctioning of neonates receiving ventilation. The amount of oxidatively modified protein may provide a quantitative assessment of oxygen toxicity and of pulmonary antioxidant defenses.

Topics: Bronchoalveolar Lavage Fluid; Chromatography, High Pressure Liquid; Chronic Disease; Dexamethasone; Female; Humans; Infant, Newborn; Infant, Newborn, Diseases; Ketones; Lung; Lung Diseases; Male; Oxidation-Reduction; Oxygen; Phenylhydrazines; Proteins; Respiration, Artificial; Respiratory Distress Syndrome, Newborn

1. Concentrations of ascorbic acid (ascorbic and dehydro-ascorbic; A + D; measured by the 2,4-dinitrophenylhydrazine method) of nearly three times those of plasma are present in gastric juice samples from patients with normal gastric histology. 2. A significant reduction in gastric juice ascorbic acid (A + D) was observed in patients with chronic gastritis. This reduction in concentration was independent of the grade of gastritis. 3. Concentrations of ascorbic acid (A + D) in gastric biopsy specimens were consistently higher in the antrum than in the body of the stomach. 4. These data demonstrate that considerable quantities of ascorbic acid (A + D) are normally 'secreted' into the stomach. 5. Ascorbic acid (ascorbic only; A; measured by h.p.l.c.) was present predominantly in its biologically active form in the patients with normal gastric histology. However, in patients with gastritis, independent of grade, ascorbic acid was present predominantly in its oxidized, biologically inactive form.

Topics: Adult; Aged; Ascorbic Acid; Chromatography, High Pressure Liquid; Chronic Disease; Female; Gastric Juice; Gastritis; Humans; Hydrogen-Ion Concentration; Leukocytes; Male; Middle Aged; Phenylhydrazines