James A. Warth

Altered amount and activity of superoxide dismutase in sickle cell anemia.

The amount and activity of superoxide dismutase (SOD) (EC 1.15.1.1) were measured in red cells collected from 50 white controls, 101 black controls, 50 patients with sickle hemoglobin (SS Hb), 12 with sickle trait, and 11 with other sickling hemoglobinopathies. Red cells from normal black subjects had more SOD amount and activity than normal whites (1.77 U/mg Hb and 2.96 μg/mg Hb vs. 1.47 U/mg Hb and 2.64 μg/mg Hb, respectively) or blacks with SS Hb or other sickling hemoglobinopathies. Patients with more severe manifestations of SS Hb had lower levels of SOD activity than those with milder symptoms but had the same amount of enzyme protein. Individuals with sickle trait had amounts and activities of SOD comparable to black controls. An alteration in defense to free radical oxygen may play a role in the severity of symptoms experienced by patients with homozygous sickle cell disease.— Schacter, L.; Warth, J. A.; Gordon, E. M.; Prasad, A.; Klein, B. L. Altered amount and activity of superoxide dismutase in sickle cell anemia. FASEB J. 2: 237‐243; 1988.

A case of bleeding requiring hospitalization that was likely caused by an interaction between warfarin and levamisole

Warfarin is one of the most commonly used oral anticoagulants. Many medications have been shown to influence the prothrombin time in patients treated with warfarin by various mechanisms. We observed a major bleeding episode that resulted from a probable interaction between levamisole (Ergamisol), 5‐fluorouracil, and warfarin. It is conceivable that many patients who are predisposed to thromboembolism because of cancer and surgery will be taking this combination of medications.

Direct measurement of the internal viscosity of sickle erythrocytes as a function of cell density

The rotational dynamics of TEMPAMINE can be used to study directly the intracellular environment. The extracellular signal from TEMPAMINE is broadened away by the use of potassium ferricyanide which does not enter the cell. The EPR signal which results when 1 mM TEMPAMINE, 120 mM ferricyanide, and erythrocytes are mixed together arises from TEMPAMINE only in the intracellular aqueous space. The relative viscosity measured by the motion of TEMPAMINE in various control environments is: water at 37 degrees C = 1; human plasma at 37 degrees C = 1.1; internal aqueous environment of washed erythrocytes or whole blood at 37 degrees C = 4.92 +/- 0.32. Erythrocytes can be fractionated by density. In sickle-cell anemia (SS), the percentage of cells we find with density greater than 1.128 g/ml is 15-40%, in normals (AA) and sickle trait (AS) 1%. By direct spin-label measurements with TEMPAMINE we show, for the first time, that the relative internal viscosity (eta mu) of these dense erythrocytes is markedly elevated and density-dependent. Our results show that (1) eta mu increases with increasing cell density; (2) eta mu obtained from sickle cells is higher than eta mu obtained from normal cells at a given density, and this effect is greater at 37 degrees C than at 20 degrees C; (3) eta mu is proportional to MCHC, but eta mu in erythrocytes is higher than eta mu obtained from in vitro preparations of hemoglobin S at equivalent concentrations. We conclude that the relative internal viscosity of erythrocytes is affected by three factors: the state of cell hydration, the amount of hemoglobin polymer present, and the potential interactions of the cell membrane with intracellular hemoglobin.

Elimination of the settling artifact in the nuclear magnetic resonance spectroscopy of living cells

Nuclear magnetic resonance spectroscopy has become a powerful tool for metabolic investigations on living cell suspensions. However, unless mechanical means are used to maintain the cells in dispersion, settling occurs during the NMR experiment. Because high packed-cell volumes are generally used to produce maximum NMR signals, settling may be inapparent to the eye, leading to unrecognized artifactual changes in NMR spectra. Such artifacts include time-dependent loss of signal intensity when the sample volume approximates the sensitive volume of the NMR probe, and time-dependent increase in signal intensity when the sample volume exceeds the sensitive volume. Through the addition of the polysaccharide arabinogalactan, increasing the buoyant density of the suspending medium to approach that of the cells, we have eliminated cell settling and improved the quality of 31P NMR spectra of human erythrocytes.

The phosphoproteins of the sickle erythrocyte membrane

The uptake of 32P from exogenous 32Pi into membrane proteins of sickle erythrocytes has been analyzed. The phosphorylation of spectrin is normal in sickle cells. There is, however, a substantial increase in 32P in the sialoproteins of the membrane, which can be demonstrated after fractionation or selective proteolysis. Normal and sickle erythrocytes were separated on Stractan gradients and average cell age was determined using the remaining pyruvate kinase activity as a marker. The altered phosphorylation of sickle cells was not seen in young normal cells, suggesting that it was not related to cell age. The altered phosphorylation was also not correlated with the level of reticulocytes in these fractions. This result is further evidence for abnormalities in the sialoproteins of sickle erythrocytes and is the first demonstration of altered sialoprotein phosphorylation in the red cell.

Intraerythrocyte pH, pCO2 and the Hexose Monophosphate Shunt

Summary. We have documented a rise in pCO2 when erythrocytes are haemolysed by freeze‐thaw using solid CO2 and methanol. This is partially corrected by preventing leakage of CO2 into the system. The remaining increment is partially explained by stimulation of the hexose monophosphate shunt when erythrocytes are haemolysed by this technique.

Warfarin-Induced Skin Necrosis in a Patient with Heparin-Induced Thrombocytopenia: Two Diseases or One?

A 64-year-old woman with colon carcinoma presented with subsegmental pulmonary emboli. Platelet count on presentation was 598 ×109/l. The patient was anticoagulated with intravenous heparin. By hospital day 3, heparin was replaced with enoxaparin and warfarin. On hospital day 6, the patient developed a 20 × 15 cm area of necrotic skin on her left hip and a 1 × 3 cm area of necrosis on her right hip. By that time, her platelet count had fallen to 433 ×109/l. Three days later (hospital day 9), anticoagulation was switched from the combination of enoxaparin and warfarin to argatroban. Her platelet count reached a nadir of 82 ×109/l by the 12th hospital day. The areas of skin necrosis had never been sites of heparin injection. Heparin/platelet factor 4 antibody, sent on hospital day 9, returned positive and 14C-serotonin release assay was also positive. This case illustrates that processes underlying heparin-induced thrombocytopenia (HIT) may also underlie warfarin-induced skin necrosis. Skin necrosis may be the earliest manifestation of HIT and need not be accompanied by thrombocytopenia. This patient’s course illustrates that HIT should be considered in all patients presenting with skin necrosis while receiving anticoagulation with heparin or a combination of heparin and warfarin.

Nocardia asteroides-infected aneurysm of the aorta : Case report and review of the literature

Infected aneurysms of the aorta were first described as a result of septic emboli or contiguous spread from bacterial endocarditis and are usually caused by Staphylococcus or Salmonella species. We report a case of Nocardia-associated infected aneurysm of the native suprarenal aorta in an immunocompromised host. Surgical management consisted of placement of an interposition cryopreserved aortic homograft. Nocardia asteroides was identified on a microbiology specimen of the aorta and both microbiology and pathology specimens of the splenic tissue. To the best of our knowledge, this represents the first carefully documented, unique case of a Nocardia-infected aneurysm treated with homograft interposition. In addition, pathologic and microbiologic data are included from the postmortem examination 10 months later.

Simultaneous occurrence of polycythemia vera and Waldenstrom macroglobulinemia: a case report and review of the literature.

Polycythemia vera and lymphoproliferative disorders can occur simultaneously. Lymphoproliferative disorders reported to occur simultaneously with polycythemia vera include chronic lymphocytic leukemia (CLL), non-Hodgkins lymphoma (NHL), and acute lymphoblastic leukemia (ALL). Different theories have attempted to explain this occurrence. Some implicate a common cell of origin to the two disorders, others include chance alone, yet others implicate an underlying humoral or immune mechanism caused by the first disorder leading to a second clonal expansion. We report the first case of polycythemia vera with a simultaneous diagnosis of Waldenstrom macroglobulinemia, and we review the literature trying to explain this unusual occurrence.

Intraerythrocyte pH and physiochemical homogeneity.

Summary In order to determine the physiochemical homogeneity of the human red cell, intraerythrocyte pH was simultaneously measured using the weak acid 5,5-dimethyl-oxazolidine-2,4-dione (DMO) and the weak base nicotine. If a cell is homogeneous, such measurements will yield the same result. If a cell is heterogeneous, the DMO reading will be closer to the highest pH in the cell system, while the nicotine will read closer to the lowest pH. The results show no significant difference between the intracellular pH obtained by either of these methods (average by DMO = 7.10, by nicotine = 7.06 at an average external pH of 7.33). We conclude that the human erythrocyte is physiochemically homogeneous.