Elevated breath pentane in heart failure reduced by free radical scavenger.

UNLABELLED: Pentane, a product of lipid peroxidation, has been detected in situations involving ischemic injury. Such injury may be limited if lipid peroxidation can be controlled by antioxidants. The role of lipid peroxidation in chronic heart failure (CHF) was assessed by measuring breath pentane in patients with CHF vs. age matched controls. The effect of a free radical scavenger on pentane released during CHF was also measured. Pentane levels were correlated with the daily dose of captopril, a sulfhydril-containing drug used to treat CHF, which is an angiotensin converting enzyme inhibitor. To separate the scavenging effects of captopril from the pharmacologic effects of converting enzyme inhibitors, a crossover study using a nonsulfhydril inhibitor was used. Patients with CHF excreted (p < 0.005) high concentrations of pentane (5.7 +/- 2.1 vs. control 3.6 +/- 1.2 nmol/l). Patients treated with captopril also had significantly higher (p < 0.05) excretion of pentane than the control patients (4.7 +/- 1.3 vs. 3.6 +/- 1.2 nmol/l). The dose of captopril was inversely proportional to the concentration of pentane excreted (r = 0.55, p < 0.05). Pentane excretion during captopril therapy was significantly lower before (p < 0.01) and after (p < 0.02) nonsulfhydril inhibitor therapy. CONCLUSION: breath pentane is elevated in CHF and it can be reduced by a free radical scavenger. This reduction of pentane excretion is not a converting enzyme inhibitor class effect.

High breath pentane concentrations during acute myocardial infarction.

To investigate whether reperfusion after myocardial ischaemia leads to free-radical-mediated peroxidation of membrane lipids and cell damage, we measured pentane, a product of lipid peroxidation, in the breath of 10 healthy control subjects and in 20 consecutive patients with suspected acute myocardial infarction. 10 of these patients showed no myocardial damage on electrocardiography (patient control group) and 10 satisfied standard diagnostic criteria for acute myocardial infarction. The three groups were well matched for age, sex, underlying disease, and smoking habits. The time from onset of chest pain to breath collection was similar in the patient control and acute myocardial infarction groups. The breath pentane concentration was higher (p less than 0.0001) in the acute myocardial infarction group (4.96 [1.15] nmol/l) than in the patient control (1.96 [1.04] nmol/l) and healthy control groups (1.71 [0.87] nmol/l). Lipid peroxidation during acute myocardial infarction reflects action of oxygen radicals and their potential for contribution to the pathogenesis of tissue damage.

Characterization of the immunoprotective antigen of ribosomal preparations from Haemophilus influenzae.

This investigation was designed to characterize the immunoprotective antigen of ribosomal preparations from Haemophilus influenzae. The ribosomes that elicited 80 to 90% protection contained 25% protein and 75% ribonucleic acid but did not contain any detectable hexoses. The immunodiffusion and hemagglutination inhibition tests also failed to demonstrate that the capsular material (polyribose phosphate) was in ribosomal preparations. Treatment of ribosomes with ribonuclease degraded 78% ribonucleic acid but did not affect the immunogenicity of such preparations. The proteolytic enzymes reduced the immunogenicity of ribosomes corresponding to the amount of protein degraded. The protection elicited by ribosomal protein extracted with 2-chloroethanol was comparable to that induced by intact ribosomes. In contrast, the low levels of protection observed by immunization with phenol-extracted ribonucleic acid were dependent on the amounts of contaminating protein. Finally, immunogenicity of ribosomal ribonucleic acid and protein was abrogated by treatment with proteolytic enzymes. These results clearly indicate that the protein associated with Haemophilus ribosomes is the major immunoprotective antigen.