The erythrocyte effects of haemoglobin O(ARAB).

To test the hypothesis that HbOARAB induces an increase in red cell mean corpuscular haemoglobin concentration (MCHC), we studied members of four Tunisian families who were either homo- or heterozygous for HbOARAB or were double heterozygotes for HbS and HbOARAB. The alpha-gene status was also tested. The findings included: (1) Distinctive variation in red cell density (MCHC) as determined by separation of red cells on isopycnic gradients: (a) All red cells from patients homozygous for HbOARAB were denser than normal red cells, as is observed for homozygous HbC patients. (b) In patients heterozygous for HbOARAB, red cell density was strongly influenced by the presence of alpha-thalassaemia. The coexistence of -alpha/alphaalpha resulted in an average red cell density slightly greater than normal (AA) red cells. Patients heterozygous for HbOARAB with a normal complement of four alpha genes had denser red cells similar to sickle cell disease with some cells of normal density but with most cells very dense. (c) Finally, the double heterozygotes for HbS and HbOARAB had significant haemolytic anaemia and red cells denser than normal with some as dense as the densest cells found in sickle cell anaemia. (2) Reticulocytes in patients homozygous for HbOARAB were found in the densest density fraction of whole blood. (3) Cation transport in patients homozygous for HbOARAB was abnormal, with K:Cl cotransport activity similar to that of HbS-Oman and only somewhat lower than in sickle cell anaemia red cells. The activity of the Gardos channel was indistinguishable from that found in HbS, HbC and HbS-Oman cells. We conclude that the erythrocytic pathogenesis of HbOARAB involves the dehydration of red cells due, at least in part, to the K:Cl cotransport system. The similarity of the charge and consequences of the presence of both HbC and HbOARAB, which are the products of mutations at opposite ends of the beta-chain, raises the possibility that this pathology is the result of a charge-dependent interaction of these haemoglobins with the red cell membrane and/or its cytoskeleton and that this abnormality is present early in red cell development.

Degradation study of catecholamines, indole amines and some of their metabolites in different extraction media by chromatography and electrochemical detection.

Optimal conditions for the extraction from brain tissue and the simultaneous quantification of catechol and indole derivatives were determined after a systematic degradation study in water and perchloric acid. The roles of three parameters, namely temperature, presence of antioxidant agents, and time, were considered. Adrenaline, noradrenaline, dopamine, homovanillic acid, 5-hydroxytryptophan, 5-hydroxyindole acetic acid, serotonin, and epinephrine were separated by HPLC and detected electrochemically. The results indicated a great instability of the indole derivatives at an ambient temperature, in an acid medium, and in the absence of a protective agent. Therefore, when perchloric acid has to be used for deproteinization, the lowest concentration (0.1 M) is preferable. The samples have to be kept on ice, in darkness, and protected by ascorbic acid and sodium ethylenediamine tetracetate.

Toxicological analysis of phenylethylamines by high performance reversed-phase ion-pair partition thin-layer and liquid chromatographies.

A rapid and specific method was developed to identify phenylethylamines in urine. After an organic extraction at appropriate pH, reverse phase ion-pair partition chromatographies were used: a high performance thin-layer test followed by high performance liquid chromatography. The use and benefits of the procedure are described in detail and compared with other methods. In a very short time (10 min) the presence of phenylethylamine is detected on a thin-layer plate. In the case of positive result the product is then specifically identified by high performance liquid chromatography by means of a complete UV spectrum traced directly on the eluated compound. The sensitivity of the method is highly increased because the detection is operated at 215 nm.