Pseudohyperphosphataemia incidence in an automatic analyzer.

A routine blood analysis, using the Hitachi 717 analyser, of an asymptomatic patient with multiple myeloma revealed a phosphate concentration of 6.2 mmol/l (reference range 0.8-1.4 mmol/l). There was no clinical or biochemical evidence for secondary hyperphosphataemia. Two additional myeloma patients with a normal renal function were found to have serum phosphate concentrations of 5 and 4.7 mmol/l. Globulin-depleted sera of these patients were found to have phosphate levels within the normal range as assayed by a Hitachi 717. All these patients were found to have normal inorganic phosphate levels when a SMAC autoanalyser was used, thus indicating spurious readings by the Hitachi 717. The incidence of pseudohyperphosphataemia in 298 patients with normal renal function and hyperglobulinaemia was 8%. To test the direct effect of globulin on phosphate analysis by the Hitachi 717, globulin was precipitated from serum of myeloma and non-myeloma patients by ammonium sulphate. The analysed data showed a positive correlation between globulin concentration and the spurious phosphate levels. Furthermore, even when inorganic phosphate was completely removed from the tested samples, spurious phosphate readings were detected in the presence of globulins from either myeloma or non-myeloma patients by Hitachi 717. It can be concluded that the ammonium molybdate method for determining inorganic phosphate in the Hitachi 717 gives spuriously high phosphate levels in the presence of a high serum globulin concentration.

Ultrastructural observations on mast cell degranulation and its prevention.

The surface alterations of rat peritoneal mast cells during degranulation induced by calcium chloride (CaCl2) and its prevention by salbutamol sulfate (Sal. Sulf.), chlorpheniramine maleate (CM), and disodium cromoglycate (DSCG) were followed with a scanning electron microscope. CaCl2 caused a protuberation of the cytoplasmic granules already after 30 s, an advanced degranulation after 60-75 s, and a complete destruction of the cells after 180 s of incubation. The degranulation process was prevented by Sal. Sulf., CM, and DSCG. A comparison of the surface changes induced by these agents with the ultrastructural findings observed with a transmission electron microscope showed that neither Sal. Sulf. nor CM prevented the alterations of the internal structure of the cells, suggesting that these substances act mainly on the cytoplasmic membrane. The best prevention for both the surface and the internal structure of the cells was obtained by DSCG, indicating that this substance is a stabilizer of both membrane and internal organelles of the mast cells.

A new cytogenetic aspect of polycythemia vera.

The cytogenetic findings in a group of 15 polycythemic patients are reported. G and C banding techniques were used on bone marrow and peripheral blood preparations. Major chromosomal aberrations were found in four out of the 15 patients, an incidence similar to that found in other studies on polymorphism. The most interesting finding concerned the chromosomal polymorphism of the pair 19. A possible relation to the etiology of the disease is discussed.

3H-thymidine, 3H-uridine and 3H-leucine uptake in erythroblasts of patients with chronic renal failure.

The in vitro incorporation of 3H-thymidine, 3H-uridine and 3H-leucine, reflecting the synthetic capacity for DNA, RNA and protein, respectively, was detected by radioautography in the erythroid precursors of 10 patients with chronic renal failure. The results were compared with the uptake of the isotopes in the erythroid precursors of healthy subjects. The pattern of incorporation for all three isotopes in the patients' cells was similar to that of control cells, but significantly lower. The possible causes of this difference are discussed.

Corticosteroid effect on eosinophils in vitro: ultrastructural studies.

The effect of corticosteroids, ultracortene and ACTH, on the eosinophilic cells of a patient with hypereosinophilic syndrome has been studied in vitro. Both drugs caused a marked decrease in the number of specific granules, a disappearance of their surrounding membrane and an almost complete destruction of their crystals. In addition, vacuolization of the cytoplasm, swelling of the mitochondria and distortion of their cristae were found. Incubation of the eosinophils with the antihistaminic drug mepyramine, did not produce ultrastructural alterations.