Morphologic changes in pulmonary muscular arteries may modify the mechanisms that regulate the pulmonary vascular tone and contribute to maintaining an adequate ventilation-perfusion (VA/Q) matching in patients with chronic obstructive pulmonary disease (COPD). To analyze the relationships between the abnormalities of pulmonary muscular arteries and the degree of VA/Q inequality, and to assess the effect of these abnormalities on the changes in VA/Q relationships induced by oxygen breathing, we studied a group of patients with mild COPD undergoing resective lung surgery. According to the degree of airflow obstruction and the increase in VA/Q mismatch produced by 100% O2 breathing (delta logSD Q), patients were divided into three groups: (A) patients with normal lung function, (B) patients with airflow obstruction and a high response to oxygen (delta logSD Q > 0.4), and (C) patients with airflow obstruction and a low response to oxygen (delta logSD Q < 0.4). Pulmonary arteries in Groups B and C showed narrower lumens and thicker walls than in Group A. These morphologic changes were produced mainly by an enlargement of the intimal layer and were more pronounced in Group C than in Group B. The assessment of intimal area as a function of artery diameter showed that the increase in intima in Group C took place predominantly in arteries with small diameters (< 500 microns). The mean intimal area on each subject correlated with both the PaO2 value (r = -0.46, p < 0.05) and the overall index of VA/Q mismatching (r = 0.51, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

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Serum carnitine levels may be reduced in patients with phenylketonuria (PKU) owing to low carnitine intake, deficient carnitine synthesis and acylcarnitine production from phenylalanine metabolites. In order to investigate the possible carnitine deficiency we determined serum carnitine in its different forms and the precursors and cofactors involved in its synthesis in a group of patients with PKU or hyperphenylalaninaemia. Free, total and acylcarnitine values were significatively reduced only in PKU patients with Phe-restricted diet which had not been supplemented with carnitine. Acylcarnitine/free carnitine ratio and all the other parameters studied were normal in all patients. We conclude that the low serum carnitine levels in PKU patients with a strict diet are a consequence of the low carnitine intake.

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