Calcium and potassium disturbances in acute leukemia

Predicting Ca2+ -binding sites using refined carbon clusters

Identifying Ca(2+) -binding sites in proteins is the first step toward understanding the molecular basis of diseases related to Ca(2+) -binding proteins. Currently, these sites are identified in structures either through X-ray crystallography or NMR analysis. However, Ca(2+) -binding sites are not always visible in X-ray structures due to flexibility in the binding region or low occupancy in a Ca(2+) -binding site. Similarly, both Ca(2+) and its ligand oxygens are not directly observed in NMR structures. To improve our ability to predict Ca(2+) -binding sites in both X-ray and NMR structures, we report a new graph theory algorithm (MUG(C) ) to predict Ca(2+) -binding sites. Using carbon atoms covalently bonded to the chelating oxygen atoms, and without explicit reference to side-chain oxygen ligand co-ordinates, MUG(C) is able to achieve 94% sensitivity with 76% selectivity on a dataset of X-ray structures composed of 43 Ca(2+) -binding proteins. Additionally, prediction of Ca(2+) -binding sites in NMR structures was obtained by MUG(C) using a different set of parameters, which were determined by the analysis of both Ca(2+) -constrained and unconstrained Ca(2+) -loaded structures derived from NMR data. MUG(C) identified 20 of 21 Ca(2+) -binding sites in NMR structures inferred without the use of Ca(2+) constraints. MUG(C) predictions are also highly selective for Ca(2+) -binding sites as analyses of binding sites for Mg(2+) , Zn(2+) , and Pb(2+) were not identified as Ca(2+) -binding sites. These results indicate that the geometric arrangement of the second-shell carbon cluster is sufficient not only for accurate identification of Ca(2+) -binding sites in NMR and X-ray structures but also for selective differentiation between Ca(2+) and other relevant divalent cations.

Electrolytes and whole body potassium in acute leukemia

In a consecutive series of 22 patients with acute leukemia, the total body potassium was studied in 18 patients on 39 occasions during relapse and remission. Total body water was also determined. A control group consisting of 88 age-matched healthy volunteers was also studied. The patients had a significantly lower mean potassium concentration, per kg body weight, per kg lean body mass and per kg water, than the controls (p less than 0.001). Individually, 11 out of the 18 patients had at least one value below the lower 95% confidence limit. Hypokalemia was frequent both in the patients with low (7/11) and normal (3/6) potassium per kg lean body mass. Five of 13 investigated patients showed laboratory indications of secondary hyperaldosteronism, which might be partly responsible for the hypokalemia. Increased serum or urine levels of lysozyme were found in 62% of the patients.

Management of septicemia and early death in acute leukemia

The frequency of fever days was measured in 67 patients with acute leukemia in the initial phase until remission was obtained or the patient died. A total of 3411 hospital days were studied. Three antibiotic schedules were examined between 1970 and 1975. There were 50% fever days when penicillin and streptomycin were combined as initial antibiotics, 37% when cephalosporin and gentamycin were used, and 31% when, in addition, semi-isolation was used prophylactically and granulocytes were given in a therapeutic attempt (0.05 greater than p greater than 0.01). The corresponding frequencies of early death were 9/21 (43%), 6/23 (26%) and 5/23 (22%). Early death occurred on an average 14, 23 and 21 days after admission. The frequencies of remission (complete and partial) were 8/21 (38%), 12/23 (52%), and 13/23 (57%). A randomized subgroup (12 patients) with intestinal sterilization was studied separately. It had 28% fever days, which is significantly less (p less than 0.01) than in the 13 patients given the same systemic antibiotics without intestinal sterilization. Fever was significantly lower (0.05 greater than p greater than 0.01) on the day after a series of granulocyte transfusions than before, although only 10(9) granulocytes were given. However, this fever reduction may have been due to concomitant antibiotics.

Metabolic disorders in acute myeloid leukaemia

Metabolic balance studies were carried out in 17 unselected patients with acute myeloid leukaemia. Widespread metabolic disturbances were observed. Serum Na fell below 135 mmol/1 in 14 patients (82%) and 11 patients (64%) developed hypokalaemia. An increased osmolal clearance caused by a release of electrolyte and blast cell waste (i.e. urea, urate, etc.) during chemotherapy appeared to be the principle cause of natriuresis and hyperkaluria. Seven patients had proteinuria before and eight others developed it during antileukemic therapy. Nine patients (53%) developed proximal renal tubular dysfunction with aminoaciduria, hyperphosphaturia and incomplete reabsorption of urate. No significant relation was found between this widespread glomerulo-tubular dysfunction and lysozymuria. We suggest that antileukaemic drugs release unidentified substances from blast cells which are toxic to the kidney. Metabolic alkalosis in six patients (35%) was probably related to volume depletion and hypokalaemia, while two patients developed acidaemia with the onset of renal failure. Hypocalcemia in seven patients (41%) had a multifactorial basis: hyperphosphaturia, septicaemia, malnutrition and cytotoxic drugs were among the probable causes.

Autopsy findings in leukaemia

Out of 38 leukaemic cases only 16 had extensive leukaemic infiltration at death. 15 patients had slight or moderate and 7 no infiltration at all. 12 of the 15, and 5 of the 7 died with septicaemia. The latter patients must have died of complications rather than of the leukaemia itself. Although it has been possible to reduce the incidence of septicaemia during life, terminal septicaemia does not yet seem to be preventable. Septicaemia was revealed at autopsy in 27 of 38 patients; 25 of these also had clinical signs of septicaemia before death. Necrotizing gastrointestinal lesions may cause endogenous infection. In the present material, almost every second patient had fungal septicaemia. Out of 7 patients having oral candidiasis in vivo 5 had systemic candidiasis at autopsy, but only half of the patients with systemic candidiasis had visible oral growth. Modern treatment of leukaemia seems to be able to prevent intracranial haemorrhage in 90% of the cases. On the other hand, vacuolization of muscle and liver tissue was a frequent finding in leukaemia. It is suggested as being caused by fatty degeneration. Vacuolization of myocardial cells was found in 7 out of 13 cases. Among these 7, 4 had had intermittent hypokalaemia.