The effect of copper on red cell enzyme activities.

Previous studies have shown a marked effect of very high levels of copper on red cell glucose-6-phosphate dehydrogenase and glutathione. When the effect of more nearly physiological levels of copper were studied, red cell hexokinase, phosphofructokinase, phosphoglyceric kinase, pyruvate kinase, and 6-phosphogluconate dehydrogenase were found to be inhibited. Inhibition was observed both when copper was added directly to hemolysates or when hemolysates were prepared from red cells from whole blood which had been incubated with copper and washed. The inhibition of red cell enzymes by copper was completely reversed by the addition of EDTA.

A liver-type mutation in a case of pronounced erythrocyte phosphofructokinase deficiency without clinical expression.

A marked erythrocyte phosphofructokinase deficiency was detected in a healthy man. His enzymatic activity was only 25% that of normal controls. His father and his son had erythrocytic phosphofructokinase activities of 50-55% that of normal controls. The chromatographic separation of erythrocytic phosphofructokinase isozymes, as well as immunological studies revealed a decrease in L-type phosphofructokinase activity. The lowered erythrocytic L-type phosphofructokinase activity was not accompanied by a decreased level of L-type phosphofructokinase in proteins. The L/M subunit ratio was similar to that of normal subjects. The defect resulted from the synthesis of stable L-type mutant subunit with high electrophoretic mobility. White blood cells, which synthesize mostly the same isozyme as L-type phosphofructokinase also showed a decreased activity and a high electrophoretic mobility. In spite of this important deficiency, and of significant metabolic alterations (a slight decrease in ATP; 2,3-diphosphoglycerate; triose phosphate), hemolysis did not appear in the propositus.

Evidence for the involvement of (Cu-ATP)2- in the inhibition of human erythrocyte (Ca2+ + Mg2+)-ATPase by copper.

The effects of copper on the activity of erythrocyte (Ca2+ + Mg2+)-ATPase have been tested on membranes stripped of endogenous calmodulin or recombined with purified calmodulin. The interactions of copper with Ca2+, calmodulin and (Mg-ATP)2- were determined by kinetic studies. The most striking result is the potent competitive inhibition exerted by (Cu-ATP)2- against (Mg-ATP)2- (Ki = 2.8 microM), while free copper gives no characteristic inhibition. Our results also demonstrate that copper does not compete with calcium either on the enzyme or on calmodulin. The fixation of calmodulin on the enzyme is not altered in the presence of copper as shown by the fact that the dissociation constant remains unaffected. It may be speculated that (Cu-ATP)2- is the active form of copper, which could plausibly be at the origin of some of the pathological features of erythrocytes observed in conditions associated with excess copper.

Intoxication by benzodiazepines: studies with diazepam used as a model compound suggest an interaction with red blood cells calmodulin dependent (Ca2+, Mg2+) ATPase.

20 patients under therapy or intoxicated by benzodiazepines were studied. A partial inhibition of (Ca2+, Mg2+)ATPase on 'B' membranes (CaM rich membranes) was evident in 2 cases. A total inhibition of (Ca2+, Mg2+) ATPase on both 'B' and 'A' (CaM depleted) membranes was noted in 1 case: the patient who was severely intoxicated had pronounced hemolysis. As an attempt to elucidate the mechanism of this action, the effect of diazepam chosen as model compound was studied on 'B' and 'A' membranes prepared from normal human RBC previously incubated with diazepam. A high concentration of diazepam, corresponding to a 20-fold therapeutic level results in a 50% inhibition of the maximal activity of the enzyme on 'B' membranes. It may be speculated from these experiments that the effect of high concentration of benzodiazepines on CaM dependent (Ca2+, Mg2+) ATPase leads to accelerated RBC destruction.

[Blood transfusion despite early use of erythropoietin: failure or limit of therapy? Annual cohort study of premature infants weighing less than 1500 g]. / Transfusion malgré érythropoïétine recombinante: échec ou limite du traitement? Etude d'une cohorte annuelle de poids de naissance inférieur à 1 500 g.

STUDY: Prospective, observative study. SETTING: Neonatal intensive care unit in a university tertiary care hospital. AIMS: 1) Assessment of blood transfusion requirement. 2) Demonstration of haematocrit and hemoglobin level difference at birth between transfused and non-transfused infants. 3) Assessment of iron mass before and after early iron supplementation. POPULATION: All premature infants without cardiopathy, surgical diseases, hemolysis or haemorrhage, at less than 30 weeks of gestational age or less than 32 weeks, weighing less than 1,500 grams, with respiratory distress syndrome admitted into the unit during the year 1998, were included in the study. Each received erythropoietin (750 U.kg-1.wk-1) with intravenous iron supplements from day 5 (0.017 mmol.kg-1.d-1), then orally (0.17 mmol.kg-1.d-1). RESULTS: Seventy-nine premature infants were included in this study. 1) Sixty-seven percent of the transfusions occurred during the first 14 days of life. 2) Haematocrit and hemoglobin levels at birth were significantly different between transfused and non-transfused infants (P < 0.001) and remained different for infants of less than 28 weeks (P < 0.01). 3) After six weeks of iron supplementation (mean 0.31 mmol/kg), the ferritin level had significantly decreased in the non-transfused (P < 0.001) and transfused population (P < 0.01). CONCLUSION: Increasing the haematocrit and the hemoglobin levels at birth, for example by placentofetal transfusion, could decrease the number of early transfusion. Early intravenous iron supplementation had no side effects but did not maintain iron levels.

[Interest of prolonged peridural anaesthesia in the treatment of thoracic injuries (author's transl)]. / Intérêt de l'analgésie péridurale prolongée dans le traitement des volets thoraciques. A propos de 29 observations.

Prolonged peridural analgesia relieves the pain and thanks to immediate return of ventilatory function avoids most complications of poor prognosis in mobile sternum. After a historical and pharmacological survey, the authors describe a standard technic, the course and the necessary supervision. The study of 29 cases of mobile sternum of variable gravity, treated in this way, permitted the authors to determine the indications and contra-indications and the role of associated treatments: physiotherapy, surgical fixation, respiratory assistance. The rare failures may benefit from another therapeutic method.

[The binding of iron to normal human erythrocyte membranes and its intracellular penetration as a function of different glucides]. / Etude de la fixation du fer sur la membrane de l'hématie humaine normale et de sa pénétration intracellulaire en fonction de différents glucides

In vivo intestinal absorption of iron in rat is greatly enhanced by Lactose and D-Xylose. Both sugars are also able to increase the amount of iron bound to the red cell membrane in the animal. Similar effects have been noted when using human normal red cells. Lactose of D-Xylose are able to convert into an active transport curve the linear diffusion curve which is noted when iron is used without any ligand. It is possible to quantify the effect of both sugars on the flux of iron towards the red cell membrane.

[Comparison of the metabolism of 2 injectable iron preparations (sorbitol iron and polymaltose iron) with the metabolism of transferrin and hemoglobin iron]. / Comparaison du métabolisme de deux préparations de fer injectable (fer-sorbitol et fer-polymaltose) avec le métabolisme du fer transferrinique et du fer hémoglobinique

Iron distribution in the different organs and chemical compartments of the rat has been studied after intravenous injection of 59Fe-sorbitol (Jectofer-Astra) and 59Fe-polymaltose (Fer Hausmann Lucien) and compared with the metabolism of 59Fe bound to transferrin and to hemoglobin. Both parenteral iron preparations are utilized more slowly than Iron-transferrin. The speed of red cell incorporation of 59Fe from sorbitol is similar to the hemoglobin iron utilization (half incorporation in red cells: 4 to 5 days). Iron polymaltose is much more slowly utilized (half incorporation in the red cells: 13 to 15 days). One third of the 59Fe from sorbitol is eliminated in urine, the remaining iron being taken up to 60% by the liver and to 30% by the bone marrow. It is very quickly catabolized, since as early as the first hour after injection most of the 59Fe is bound to polymaltose till the 14th day. Between the third and fourth week 25% of the 59Fe from polymaltose is found in hemosiderin. These metabolic differences are also found in man: 59Fe from iron sorbitol is found in urine after injection, is mobilized by desferrioxamine after six days, and eliminated through dialysis membranes. On the other hand the 59Fe from polymaltose is slowly but completely utilized and not mobilized by desferrioxamine in the first week after injection. The data give the indications for use and the pharmacokinetics of two forms of parenteral iron and oral preparations in the treatment of iron deficiency.

Increased risk of lung cancer in the melting department of a second Ontario steel manufacturer.

A study of lung cancer among workers at an electric arc steel making operation was performed to follow up on the observation of a lung cancer cluster in the melt shop of another plant. The study group comprised 335 deceased men identified from plant records. Eight of thirty men who had ever worked in the pouring pit area died of lung cancer (PMR 276; p less than 0.01), but increased risk was not found elsewhere in the melting department. There was a significant trend in lung cancer risk with the length of employment in the pit area during a time window 18-30 years before death. Smoking data suggested that smoking alone could not account for the increased risk. An industrial hygiene assessment found present exposures to carcinogenic metals and silica to be within current guidelines. No polycyclic aromatic hydrocarbons were detected. This is the second steel plant for which we have found increased lung cancer risk in the pouring areas. The causative factors have not yet been identified.

[Study of proteins binding radioactive indium in vivo]. / Etude des protéines fixant in vivo l'indium radio-actif

After in vivo infusion, radio-active indium is fixed by liver and bone marrow, but more slowly and less completely than iron. It does not incorporate to haem. It is found as labelled ferritin in the liver, after the fifth day. In the bone marrow, indium is almost exclusively found as labelled transferrin; several arguments suggest the intra-cellular site of the labelled protein. Using indium may enable a better knowledge of the intermediary iron pools.

[Trans-cerebral electric analgesia: reality, hypothesis or placebo? (author's transl)]. / Electro-analgésie transcérébrale: réalité, hypothèse ou placebo?

Sixty patients undergoing major digestive surgery received the same amount of drugs for induction of anesthesia; neuroleptic, morphinomimetic and pachycurares were used and calculated in mg/kg. A randomisation list permitted to define 45 patients who received in double blind (by means of a long electrical cord), an electrical current varying for each protocol; the control group (15 patients) did not receive an electrical current. Statistical study of the amount of drugs used for follow of anesthesia shows no real effect of electrical analgesia for digestive surgery.

Decreased red cell enolase activity in a 40-year-old woman with compensated haemolysis.

A 40-year-old woman splenectomized 17 years previously for hereditary haemolytic anaemia was investigated in our laboratory because of persistent conjunctival subicterus associated with compensated haemolysis. The results of the autohaemolysis and osmotic fragility tests were similar to those usually observed in hereditary spherocytosis. Red cell enzyme assays indicated a decreased amount of kinetically normal enolase. The genetic transmission of this defect could not be established since the only other affected member of the family was the proposita's father who died several years ago after splenectomy for an undefined haemolytic disorder.

Metabolic changes in red blood cells in malignant lymphomas.

Serum copper levels (SCL) which are concomitantly related to red blood cell free copper are significantly increased in some malignant lymphomas in the phase of activity. This results in a profound inhibition of red cell key glycolytic enzymes, hexokinase (Hx) being the most sensitive. Fifteen patients (eight with Hodgkin's disease and seven with non-Hodgkin's lymphoma) were studied for serum and red cell copper concentrations and Hx activity. The mean red cell life span was determined using 51Cr labelled red cells. The resulting data shows that in active disease an increase in SCL was associated with a decrease in Hx activity and a shortened red cell survival. In these cases there was no evidence of autoimmune phenomena or of direct bone marrow involvement by the disease. It is suggested that the increase in copper levels results in a shortened red cell life span through a copper-induced inhibition of red cell Hx.