Lumbar myelography with iohexol in outpatients: prospective multicenter evaluation of safety

A multicenter open, noncomparative evaluation of the safety of iohexol was prospectively conducted in 81 adult outpatients undergoing screen-film lumbar myelography. Iohexol (180 milligrams of iodine per milliliter) was administered via a lumbar route at a dose of 8-17 mL. Computed tomography (CT) was performed after myelography. The safety of iohexol was assessed by monitoring adverse reactions and neurologic status and by measuring vital signs and serum laboratory values. The most frequent adverse reaction was headache (16 of 81 patients [19.7%]). Twelve patients complained of a headache on the day of the myelographic procedure, and four patients reported a headache 24 hours after the procedure. Nausea or vomiting occurred in four of 81 patients (4.9%) only on the day myelography was performed. No other neurologic abnormalities were found. Iohexol produced myelographic and CT studies of good to excellent quality in all patients. This study indicates that iohexol can be employed safely in lumbar myelography of adult outpatients.     

The conformational requirements for the mechanical precipitation of hemoglobin S and other mutants

The mechanical stability of human hemoglobin mutants was studied for the specific effects of single and double amino acid substitutions, the ligand state of each chain, and the effect of hybrids between oxy and cyanmet partners on precipitability. It was found that the beta6Glu leads to Val and the beta73 Asp leads to Asn mutations increased the degree of mechanical precipitation in the liganded but not in the deoxy form. When these mutations occurred on the same chain, the effects were approximately additive. Heat labile mutants such as Hb Gun Hill and Hb Leiden exhibited mechanical instability, but probably through a different mechanism, as very little dependence on ligand state was apparent. Studies with valency hybrids of HbS(alpha2 betas2-and-alpha2 betas2 where = cyanmet) revealed that instability was primarily determined by the state of the betas chain, which must be liganded to confer instability on the tetramer. A good agreement between surface activity and mechanical precipitability of these mutants has been found.     

Acute leukemias associated with the 4;11 chromosome translocation have rearranged immunoglobulin heavy chain genes

Studies of acute leukemia with the 4;11 translocation have yielded conflicting results regarding the lineage of the cell of origin in this disease. To investigate this issue further, we have examined the state of immunoglobulin genes in tumor cells from two affected patients, immunophenotyped their leukemic cells using a number of monoclonal antibody reagents with specificities for lymphoid or myelomonocytic antigens, and examined the malignant cells by electron microscopy. DNA was extracted from leukemic bone marrow cells and hybridized with radiolabeled DNA fragment probes specific for the constant region of immunoglobulin heavy chain and kappa and lambda light chain genes. Autoradiographs revealed rearrangement of both allelic heavy chain genes, but a germline configuration of light chain genes in both cases. Surface marker analysis showed that blasts from both patients expressed HLA-DR and the myeloid antigens Leu-M1, 1C2, 2D1, and 4B3, but lacked common acute lymphocytic leukemia antigen or T antigens. Furthermore, they did not have sheep erythrocyte receptors nor did they express surface or cytoplasmic immunoglobulin or B cell precursor determinants. Electron microscopy analysis showed that blast cells from patient 1 exhibited numerous monoribosomes, polyribosomes, and isolated strands of rough endoplasmic reticulum in their cytoplasm. These ultrastructural features are characteristic for both common acute lymphocytic leukemia and pre-B-ALL cells, but not for T-ALL or acute myelogenous leukemia cells. Peroxidase was undetectable in cells from both patients. Our study suggests that this disorder represents a unique subtype of leukemia. The cell of origin may be an early B cell progenitor that shares certain surface antigens with myeloid cells or a stem cell with the potential for both lymphoid and myelomonocytic differentiation.