S. Baar

The metabolism of α2-macroglobulin in mildly burned patients

Abstract The metabolic turnover of freshly prepared [131I]α2-macroglobulin (α2) has been studied in 11 adults, seven with relatively small burns and four normals. The catabolism of α2M increased rapidly after injury to approximately twice normal. The period of increased breakdown lasted for 10 days and then quickly fell to normal. The quantity of extravascular α2M calculated at the time of equilibrium between the intra- and extravascular pools, rose to five times normal. Considerable amounts of protein were lost from the burned area as exudate. These losses continued for at least 14 days after burning. In spite of all these changes the total intravascular α2M remained relatively normal throughout. This implies that a substantial increase in synthesis must have occurred soon after the injury. Compared with the rapid rise in plasma α2-globulin levels, α2M concentrations in the same patients increased only slightly shortly after the injury. However, the prompt acceleration of metabolism soon after burning, with an abrupt return to normal rates after 10 days, showed that α2M behaves like an acute phase protein. The possible importance of the observed changes in burned patients are discussed in relation to the known functions of α2M.

Albumin and Hydroxy-Ethyl Starch in the Cryopreservation of Red Cells—an In Vitro Study

The usefulness of a fully dialyzed albumin in ACD‐saline containing hyroxyethyl starch (HES) for cryoprotection of red blood cells has been investigated. In vitro damage was as assessed by the amount of hemolysis in the supernatant plasma, saline stability, and autohemolysis at 30 C after resuspension in fresh ACD plasma. Freeze‐thawing hemolysis was reduced to an average of 54 per cent of that of the control when the cells were processed in 14.1 g 100 ml albumin containing 11.7 g 100 ml HES. Higher concentrations of albumin reduced this difference of 46 per cent to 20 per cent. The autohemolysis test gave the best result, when 21.7 g/100 ml albumin was used as HES diluent.

Anaemia of burns

Abstract In vivo or in vitro thermal injury of red cells leads to biochemical and physical abnormalities. The relevance of these abnormalities to the development of post-burn anaemia, hypoxaemia and hypoxia are discussed and possible therapeutic measures to increase oxygen delivery to the tissues and hence reduce hypoxaemia are indicated.

A micromethod for the estimation of serum calcium

Abstract 1. (1) A colorimetric micromethod for the estimation of serum calcium was described. 2. (2) The effect of varying sodium hydroxide concentrations, and of magnesium, iron, haemoglobin, bilirubin, and heparin was investigated. 3. (3) Stability, recovery and reproducibility were examined. 4. (4) Some investigations into the nature of the complex were undertaken.

Red cell filtrability and its relationship to glycolysis and cyanosis after burning injury

Abstract Seven burned patients, all of whom received topical silver therapy, were serially investigated with respect to their red cell filtrability and stimulated and non-stimulated anaerobic and aerobic glycolysis. Five of these patients developed acute Heinz body anaemia or clinical cyanosis. It was found that red cell filtrability was low in all cyanotic patients and at its lowest preceding and during a cyanotic attack or Heinz body anaemia. Red cell glycolytic rates were increased early in all affected patients but the response to ascorbate stimulation of the hexose monophosphate shunt (HMPS) and carbon recycling was reduced, particularly during an acute attack. The implications of the findings are discussed and it is suggested that prostaglandins and/or catecholamines acting on the cell membrane may be the first step and this may be potentiated by silver.

The effect of silver compounds on the metabolism of human red cells

Summary The effect of silver nitrate (10−4M, 0·5 × 10−4M, 0·25 × 10−4M and 0·5 × 10−5M), silver acetate (10−4M), silver proteinate (10−4M[Ag]) and silver sulphadiazine (10−4M and 10−5M[Ag]), on total glycolysis, the bexose monophosphate shunt (HMPS), and lactate and pyruvate production of red cells incubated in autologous plasma was investigated. The contribution of the HMPS was determined with 14C1 labelled glucose. Cellular reduced glutathione (GSH) and methaemoglobin (MetHb) levels were also determined. 10−4M and 0·5 × 10−4M silver nitrate reduced the glycolytic rate to 20–30 per cent of normal. Lower levels of silver nitrate predominantly affected the HMPS, increasing the percentage contribution of this pathway and the amount of glucose oxidized to CO2 above the normal controls. Simultaneously, lactate formation was reduced and pyruvate formation approximately quadrupled. Silver acetate slightly stimulated glucose utilization and greatly increased the oxidative pathway. Lactate production was lowered and pyruvate formation increased to 8–10 times the norm. Silver proteinate hardly altered glycolysis. Lactate formation was moderately decreased and pyruvate slightly increased. The highest level of silver sulphadiazine decreased glycolysis and increased the absolute amount of glucose oxidatively degraded. 10−5M [Ag] as silver sulphadiazine did not alter glycolysis but lowered lactate formation and doubled pyruvate formation. GSH levels were 38 per cent or normal at 10−4M silver nitrate and 93 per cent of normal at 0·5 × 10−5M. 10−4M [Ag] as silver sulphadiazine reduced GSH to 80 per cent normal and 10−3M sodium nitrate to 94 per cent. Only the addition of silver nitrate led to increased MetHb formation. Incubation with 10−4M silver nitrate caused the oxidation of 12 per cent oxyhaemoglobin. MetHb formation decreased stoichiometrically with decreasing silver nitrate concentration. The implications of these findings are discussed.

The effect of thermal injury on the loss of calcium from calcium loaded red cells: its relationship to red cell function and patient survival.

The loss of calcium from in vitro loaded red cells from burned patients was investigated and related to cell hydration, deformability and the intra-extracellular pH difference. Episodes of delayed calcium extrusion were evident in all patients and associated with low cell water and high intracellular calcium and sodium. The pH gradient decreased, although whole blood pH remained normal. These abnormalities were reversible. Surviving patients reverted to normal in about one week with very brief recurrences. Fatal burns remained abnormal much longer and reversal to normal was very brief. Calcium extrusion and intracellular cations were always abnormal before death. Frequent extensive blood transfusions favourably affected the red cell abnormalities. Persistent delayed extrusion of calcium from in vitro red cells indicates poor prognosis for recovery.

ACUTE HEINZ-BODY ANÆMIA IN BURNED PATIENTS

Abstract Haemolytic anaemia associated with many Heinz bodies and necessitating large blood-transfusions is described in three extensively burned patients, two of whom were young children. It was delayed in onset. Anaemia improved and Heinz bodies disappeared when drugs were discontinued—cloxacillin, probenecid, and aspirin in one case; cloxacillin, ampicillin, aspirin, and digoxin in another; and gentamicin and carbenicillin in the third. Follow-up studies in the two survivors revealed no deficiency in glucose-6-phosphate dehydrogenase or other enzymes concerned with aerobic glycolysis. The burns in two patients were treated locally with silver nitrate, and they became infected with Pseudomonas œruginosa in the three patients. Two patients had episodes of unexplained cyanosis, and methaemoglobinaemia has been found in other burned patients. Though the haemolytic process seems to have been aggravated or precipitated by drugs, multiple factors may have been concerned in predisposing the red blood-cells to oxidative degradation, including the residual effects of heat, bacterial infection, and local therapy with silver nitrate. The condition may be an overt manifestation of a more frequent red-blood-cell disorder induced by burning, complications, and therapy.

The functional significance of red cell deformability and its significance in burns

Abstract Decreased red cell filtrability is often found after burning injury and a humoral mechanism is probably involved. The implications of lowered cell deformability in the lowered supply of oxygen to the burn wound are stressed. Stasis predisposes the red cell to ultimate destruction and possible therapeutic measures to prevent the loss of cell membrane elasticity are suggested.

The red cell enzyme response to thermal injury

Summary Red cell glycolysis, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and methaemoglobin reductase activities, reduced glutathione and the production of methaemoglobin under oxidative stress have been determined in 6 patients with burns ranging from 12 to 50 per cent. None developed methaemoglobinaemia. Periods of increased glycolysis, decreased response to ascorbate stimulation, lowered activity of glucose-6-phosphate dehydrogenase and increased activity of methaemoglobin reductase were found in 5 out of 6 patients. Additionally, reduced glutathione was low. Timing and magnitude of these findings suggest that individuals whose pre-injury glycolytic enzyme activities are in the upper normal range develop only a subclinical state. Oxidative stresses do not lead to acute haemolysis. The theoretical significance of the findings is discussed.