Hemoglobin Louisville (beta-42 (CD1) phe-leu): an unstable variant causing mild hemolytic anemia.

An unstable hemoglobin variant termed Hb Louisville, was found in four members of a Caucasian family, who were suffering from a mild hemolytic anemia. The variant showed a decreased stability upon warming at 65 degrees C and an increased tendency to dissociate in the presence of sulfhydryl group-blocking agents. The structural abnormality was identified as a replacement of phenylalanyl residue in position 42 (CD1) by a leucyl residue. Substitution of this phenylalanyl residue, which participates in the contact with heme, by a nonpolar leucyl residue has apparently less severe consequences than a replacement of the same residue by a polar seryl residue as in Hb Hammersmith. Oxygen equilibrium studies of total hemolysate from one Hb Louisville heterozygote indicated a decreased oxygen affinity, a marked decrease in heme-heme interaction, and a normal Bohr effect. Studies with isolated Hb Louisville were not made because it was not possible to separate the variant from normal Hb A.

Flow cytometric analysis of human erythrocytes: II. Possible identification of senescent RBC with fluorescently labelled wheat germ agglutinin.

In the first paper of a series (Gutowski, et al., 1991) we discussed the use of flow cytometry to follow at the cellular level the aging of red blood cells (RBC) in circulation, using fluorescently labelled lectins and goat anti-human-IgG and -IgM. The Coulter Epics 541 was used for those studies. In this report we describe more extensive experiments using the Becton-Dickinson FACScan flow cytometer, and compare the results with those obtained with the Coulter Epics 541. By changing sample conditions from isotonic to hypotonic, compensation for differences of the two instruments was accomplished. We confirmed our previous observations that RBC react very strongly with fluorescein isothiocyanate labelled wheat germ agglutinin (FITC-WGA) and that there is little change in the intensity of fluorescence given by RBC of all sizes with the exception of the smallest. Reactivity with FITC-WGA is markedly decreased in the presence of competitive inhibitors of sialic acid or upon enzymatic removal of sialic acid from RBC. Removal of sialic acid is accompanied by increased reaction with peanut agglutinin (FITC-PNA). Flow cytometry was also used to monitor the enrichment of a population of smallest RBC (less than 0.05%), isolated from both counterflow centrifugation and the interface obtained from Histopaque separation. These smallest RBC showed low reactivity with FITC-WGA and higher binding of FITC-goat-anti-human-IgG, and -IgM, and therefore represent the most senescent RBC, just prior to their clearance from circulation by the reticuloendothelial system. These observations are in compliance with the hypothesis that physiological desialylation of glycophorin is responsible for clearance of senescent RBC from circulation (Aminoff, 1988).

The effects of interferon-alpha/beta in a model of rat heart transplantation.

Interferons have multiple immunologic effects. One such effect is the activation of expression of cell surface antigens. Interferon alpha/beta enhance expression of class I but not class II histocompatibility antigens. Contradictory information has been published regarding the effect of interferon-alpha/beta administration in patients with kidney transplantation. In a model of rat heart transplantation we demonstrated that administration of interferon-alpha/beta accelerated rejection in a dose-dependent fashion in the absence of maintenance cyclosporine. Animals treated with maintenance cyclosporine had evidence of increased rejection at 20 days that was resolved completely at 45 days with cyclosporine alone.

Renal amyloidosis associated with systemic lupus erythematosus.

A renal biopsy of a patient who had systemic lupus erythematosus and proteinuria revealed the presence of both amyloidosis and lupus glomerulonephropathy. The association between secondary amyloidosis and systemic lupus erythematosus has only been reported in four previous cases. The significance of this association is discussed.

Ectopic subgaleal meningioma and familial neurofibromatosis.

A 14-year-old male adolescent presented with progressive enlargement of the forehead and a history of familial neurofibromatosis. Plain x-ray films of the skull, computed tomography scanning, and carotid angiography were performed prior to removal of the tumor. Pathologic verification of an ectopic subgaleal meningioma prompted the report of this rare tumor.

Intercostal nerve transfer in brachial plexus injuries: an experimental study.

Eighteen adult mongrel dogs underwent unilateral surgical disruption of the brachial plexus. Twelve animals (Group I) had as a second-stage procedure transfer of T4 and T5 intercostal nerves and their accompanying vascular bundles to the distal musculocutaneous nerve stump. Six animals (Group II) had restoration of musculocutaneous nerve continuity with conventional interpositional sural nerve cable grafts. Group I animals demonstrated significantly better electromyographic evidence of reinnervation and, comparing appearance and weight of operated and unoperated biceps muscles at the time of animal sacrifice, maintained greater gross weight and more normal overall appearance of muscle. Histologic study of muscle tissue showed no significant difference between the two groups whereas musculocutaneous nerve histology distal to all anastomoses revealed less fibrous tissue and a greater number of healthy-appearing axons in Group I. It is concluded that vascularized intercostal nerve transfer as performed in this study has theoretical advantages over conventional nonvascularized intercostal nerve transfer but additional investigation is required to make this determination. The superiority of vascularized intercostal nerve transfers over conventional interpositional sural nerve cable grafts has been demonstrated.

Digital venous anatomy.

The veins of the digits and their valves were studied in nine cadaveric hands by sequential angiography, microdissection, routine histology, cross-sectional microradiography, and corrosion casting. The findings revealed a pattern of dorsal venous arches situated over each digit. Connections between those arches were at the level of the metacarpal heads, the point at which most of the palmar venous blood joins the dorsal system by intercapitular veins. A system of valves, which were arranged so as to direct flow from distal to proximal, from palmar to dorsal, and from radial to ulnar in the hand, was present in all veins as far distal as the pulp.