Automated enantioseparation of amino acids by derivatization with o-phthaldialdehyde and n-acylated cysteines.

The enantioseparation of standard mixtures composed of protein DL-amino acids was performed by reversed-phase high-performance liquid chromatography of the corresponding diastereomeric isoindolyl derivatives, formed by automated precolumn derivatization with o-phthaldialdehyde (OPA) and a series of N-acyl-L-cysteines(Acyl-Cys). A photodiode-array detector, operating at 338 nm, was used for detection. In order to evaluate systematically the influence of the structures of the acyl group in the chiral thiol reagents, a series of novel N-acyl-L-cysteines was synthesized [acyl = n-butyryl, isobutyryl (i-But), pivaloyl, benzoyl) and the chromatographic behaviour of the diastereomers formed was compared with those of already known reagents, N-acetyl-L-cysteine and N-ter.-butyloxycarbonyl-L-cysteine. All Acyl-Cys derivatives of DL-amino acids were resolved. In particular, i-But-Cys gave the highest resolutions for most of the amino acid enantiomers in comparison with the other Acyl-Cys. Investigation of yoghurt using OPA-acetyl-Cys demonstrated the applicability of the method to a complex food matrix and the occurrence of D-Asp, D-Glu and D-Ala in this dairy product.

Increased IgD milk antibody responses in a patient with Down's syndrome, pulmonary hemosiderosis and cor pulmonale.

IgD antibody responses to cow's milk were investigated in a two-year-old black boy with evidence of pulmonary hemosiderosis and pulmonary hypertension. Initially a broad spectrum of immunologic responses to cow's milk were observed including IgD, IgE, and precipitin antibodies. Specific IgD antibody responses to cow's milk could be modulated in terms of challenge or elimination and correlated with the clinical course. It is possible that IgD antibodies may be important in milk-related pulmonary hemosiderosis.

Obstruction of the left ventricular outflow tract by the mitral valve due to a muscle band.

This paper details a rare cause of subaortic obstruction--a muscle band tethering the anterior leaflet of the mitral valve to the ventricular septum. Excision of this band released the leaflet and cured the obstruction. The patient also had a discrete subaortic membranous obstruction, the membrane being excised.

Congenital heart disease and respiratory distress syndrome. Reversal of indomethacin closure of patent ductus arteriosus by prostaglandin therapy in a preterm infant.

Two relatively large premature newborn infants with respiratory distress syndrome and ductus-dependent congenital heart disease were treated. In one, pharmacologic closure of the ductus arteriosus resulted in severe hypoxemia. The patency of the ductus as reestablished with the infusion of alprostadil (PGE1), until palliative surgery was performed. In the second case, persistent pulmonary hypertension was clinically suspected, and pharmacologic therapy was initiated without adequate cardiac evaluation. In large premature infants with respiratory distress syndrome, closure of the ductus arteriosus should not be attempted before ruling out the presence of ductus-dependent congenital heart disease. Furthermore, pharmacologic closure of ductus arteriosus can be reversed by the infusion of prostaglandin.