Effects of butylated hydroxyanisole and dicoumarol on the toxicity of menadione to rats

The enzyme DT-diaphorase catalyses the 2-electron reduction of quinones. This reaction may facilitate the detoxification of such compounds, since the hydroquinone so formed can be converted into non-toxic conjugates. There is evidence for the involvement of DT-diaphorase in the detoxification of menadione (2-methyl-1,4-naphthoquinone) in a wide range of cells and tissues in vitro, but no information is available on the possible influence of this enzyme on the harmful effects of menadione in vivo. In animals, menadione is selectively toxic to erythrocytes, causing haemolytic anaemia. In the present study, rats were treated with dicoumarol, an inhibitor of DT-diaphorase, or butylated hydroxyanisole (BHA), a substance that increases the activity of this enzyme in vivo. They were then challenged with a toxic dose of menadione. Dicoumarol increased the severity of menadione-induced haemolytic anaemia while BHA decreased it, consistent with a role for DT-diaphorase in the detoxification of menadione in vivo, as previously described in vitro.

7E3 F(ab')2, a monoclonal antibody to the platelet GPIIb/IIIa receptor, protects against microangiopathic hemolytic anemia and microvascular thrombotic renal failure in baboons treated with C4b binding protein and a sublethal infusion of Escherichia coli

We have used our previously described baboon model of infusion of both a sublethal dose of Escherichia coli and C4b binding protein to assess the impact of inhibiting platelet function with the F(ab')2 fragment of the monoclonal antibody 7E3, directed against the platelet glycoprotein (GP)IIb/IIIa receptor, on the characteristic microvascular changes. At a dose of 0.25 to 0.35 mg/kg bolus plus an infusion of 0.25 to 0.35 mg/kg over 6 hours, c7E3 F(ab')2 had only a minimal impact on fibrinogen consumption and delayed but did not prevent, the development of thrombocytopenia. Treatment with 7E3 F(ab')2, however, produced significant protection from the development of microangiopathic hemolysis and renal insufficiency. Histologic examination supported these observations, with treated animals having fewer schistocytes on blood smear and less evidence of ischemic renal changes. Treated animals also had more rapid recovery of peripheral white blood counts, suggesting a possible protective effect of treatment on ischemic damage to the bone marrow. These data indicate that potent inhibition of platelet function via GPIIb/IIIa receptor blockade can decrease ischemic organ damage in this animal model that has features similar to those found in diffuse intravascular coagulation, hemolytic uremic syndrome, and thrombotic thrombocytopenic purpura.

[Quality assurance and prevention of immuno-hemolytic incidents in blood transfusion]

Direct and indirect measures of the reliability of the transfusion process are described. These measures can be used to assess the improvement of the transfusion process with a view to preventing hemolytic incidents. Quality assurance arrangements required by their use are made clear. The stress is put upon four points: processes must be formalized and standardised; quality audits must become a routine part of the transfusion process; the system of error reporting must be extended to include all failures; anonymity must be insured to improve reporting.

[Mechanism and prevention of hemolysis in jaundiced infants in phototherapy]

It has been reported that the prolonged phototherapy results in decreased glutathione reductase (GR) activity in red blood cells. We found short-term phototherapy had the same side-effect. Besides it aggravates hemolysis of newborns during the therapy. This side-effect can be prevented by oral administration of Vit B2. Eighteen jaundiced infants who were given Vit B2 5mg three times a day during the phototherapy, and the control group of 16 patients were not given Vit B2. The results showed that the decrease of hemoglobin and the time of jaundice disappearance during the phototherapy were more favourable in the oral Vit B2 group than those of the control. These results indicated that the short-term phototherapy not only results in decreased GR activity in red blood cell, but also results in hemolysis of the newborn. This side-effect can be prevented by oral administration of Vit B2.

Dietary Platycladus orientalis seed oil suppresses anti-erythrocyte autoantibodies and prolongs survival of NZB mice

Dietary fish oils rich in 20:5(5,8,11,14,17) and 22:6(4,7,10,13,16,19) are known to replace arachidonic acid [20:4(5,8,11,14)] and to improve the immunopathology of New Zealand mice. However, in humans, similar dietary strategies may be impractical because of the high levels of fish oils required. In contrast, we believe that beneficial effects in humans may be attainable using new exotic fatty acids. Toward this end, we have focused on 5,11,14-eicosatrienoic acid [5,11,14-ETA, 20:3(5,11,14)]. This fatty acid is structurally analogous to 20:4(5,8,11,14) but lacks the delta-8 double bond essential for conversion to eicosanoids. To examine our hypothesis, diets containing the oil of Platycladus orientalis containing 3% 5,11,14-ETA, a matched control oil, fish oil, or safflower oil were fed to NZB mice. There was a dramatic delay in both the onset and the titer of direct Coombs' tests in mice fed P. orientalis oil. These were directly reflected by the abundance of 5,11,14-ETA in serum lipids. Most striking was the accumulation of 5,11,14-ETA in serum and tissue phospholipids. Though constituting only 3% of dietary fatty acids, 5,11,14-ETA was the most abundant long chain polyunsaturated fatty acid in the serum phospholipids, suggesting that it very successfully competed with 20:4 as a constituent of membrane lipids. 5,11,14-ETA was incorporated into all tissue phospholipids examined except brain phosphatidyl inositol. Among tissues, liver showed the highest incorporation of 5,11,14-ETA into phosphatidylcholine (PC), phosphatidylserine (PS), and phosphatidylinositol (PI), yet spleen PE had a higher quantity of ETA than other tissues. Lesser arachidonate in spleen PS, heart PC, and heart PI showed the evidence of replacement by 5,11,14-ETA. The data presented illustrates how new nutrition can modify autoimmune responses and emphasizes the need for further studies based on new nutritional strategies.

[Thalassemic syndromes and anesthesia]

Thalassemic syndromes are produced by a quantitative defect in the synthesis of globin chains of hemoglobin. They are classified according to the severity of the clinical picture and to the type of globin chain that is affected. Physiopathology, clinical picture, and treatment of thalassemias are discussed in this work. Thalassemia minor does not create, in general, anesthetic problems. In cases of thalassemia major one should consider not only problems derived from the severity of the anemia it self, but also those related to transfusional therapy, and to bony malformations that may disturb tracheal intubation. Discussion on the management of homozygotic thalassemia during the pre, per, and postoperative phase completes this revision.

Dexamethasone suppresses the generation of phenylhydrazine-induced anemia in the rat

The immunoactive steroid dexamethasone (DXM) was administered to rats injected with a dose of phenylhydrazine (PHZ) known to induce anemia. PHZ treatment alone resulted in a hemolytic anemia that was most pronounced on Days 1-7 after injection. This anemia was accompanied by a leukocytosis that was greatest on Days 2-7 following PHZ treatment. Lymphocytes accounted for greater than 75% of this incremental increase. In contrast, rats treated with PHZ as well as with DXM displayed erythrocyte counts and hematocrits within the normal range. Although the reticulocyte counts of these rats were higher than those of controls, they were significantly lower than those of animals receiving PHZ alone. In addition, DXM suppressed the leukocytosis and splenomegaly resulting from PHZ administration and inhibited the rise in plasma IgG titers induced by PHZ exposure. DXM also altered the ratio of peripheral blood T and B lymphocytes of PHZ-treated rats. DXM suppression of PHZ-induced anemia is further confirmation that this anemia is associated with immune activation.

[Preclinical results with 15-deoxyspergualin in experimental graft versus host disease]

The efficacy of 15-deoxyspergualin (15-DS) was tested in two models of experimental graft versus host disease (GvHD) in mice. In both models, which lead to a hemolytic anemia or to a glomerulonephritis respectively followed by subsequent death of the animals, 15-deoxyspergualin showed good therapeutic effects.

Improved red cell survival in patients with chronic subclinical haemolysis due to artificial heart valve. Observations after in vitro treatment of the cells with potassium cyanate

Red cell survival was studied with use of Chromium-51 isotope and standard haematologic tests of haemolysis. The study comprised 30 patients with normally functioning single artificial heart valves of various types. They were investigated on 2 or 3 occasions. Red cells labelled with Cr-51 were treated for 30 min with potassium cyanate (0.5 mg/100 ml) in 5% invertose or with only 5% invertose. The mean red cell survival without cyanate treatment was 25 (+/- 4.2) days. Following cyanate treatment this figure improved to 31 (+/-4.8) days. Low-grade chronic intravascular haemolysis was associated with all the valve types. Abnormal results were found in 67% and 62% of the tests in patients with ball-type valve (deBakey and Starr-Edwards, respectively). The figures for tilting disc values (Lillehei-Kaster and Björk-Shiley) were 51 and 45.5%, while Carpentier-Edwards bioprosthetic valves gave 15.5% abnormal test results. The findings thus suggested that ball valves are more haemolytic than tilting disc valves, which in turn are more haemolytic than tissue valves.

Granular activated carbon usage in chloramine removal from dialysis water

Chloramines, oxidant compounds used in municipal drinking water as sanitizing agents, potentiate hemolytic anemia when present in dialysate. Thus far, the addition of ascorbic acid to the dialysate and the use of granular activated carbon (GAC) have been the only reliable, practical methods reported for removing chloramines. This is a report on the bench-scale testing of five kinds of GAC from three manufacturers. The performance of 100 g of each carbon was studied in a 2-in-diameter column through which feed-water containing approximately 1.5 mg/L chloramines flowed downward at an average volumetric rate of 140 ml/min. The carbons' experimental capacities for chloramines differed by as much as one order of magnitude. The experimental results were used to estimate the capacity of a 9-in-diameter, 45-in-tall column of the best carbon. These scale-up estimations indicate that this sorbent may safely last through 156 5-h dialyses.

Unique sensitivity of Hb Zürich to oxidative injury by phenazopyridine: reversal of the effects by elevating carboxyhemoglobin levels in vivo and in vitro

Phenazopyridine (PAP) causes a hemolytic anemia in normal individuals who receive an overdose or in patients with decreased renal function given therapeutic doses. There are no reports of PAP-induced hemolysis in individuals with unstable hemoglobins. Therapeutic doses of PAP administered to a subject with Hb Zürich (His E7 (63) beta leads to Arg) caused a severe hemolytic anemia with many large Heinz bodies appearing in the red cells. Incubation of whole blood from three asymptomatic Hb Zürich subjects with PAP at a molar ratio of PAP/Hb of 1.3/1 produced a moderate to marked increase in methemoglobin (MHb) and Heinz body formation accompanied by a slight to moderate decrease in levels of reduced glutathione. The rates of MHb formation were proportional to the concentration of PAP. In two of the subjects the rates of formation of Heinz bodies and MHb were substantially higher than in the third subject. Red cells from five normal adults were not affected. In Hb Zürich red cells the affinity of the abnormal beta chain for carbon monoxide is much greater than that of the normal alpha and beta chains. The two subjects with higher rates of MHb and Heinz body formation were nonsmokers with in vivo carboxyhemoglobin (HbCO) levels of 4-6%. The third subject with low rates of MHb and Heinz body formation was a smoker with in vivo HbCO levels of 15-18%. Increasing levels of HbCO from 8.2% to 14.3% by the in vitro addition of CO caused a marked reduction in the rate of Heinz body formation and a moderate decrease in MHb formation. Rates of MHb formation similar to those observed in normal red cells occurred at HbCO percentages of 89.2 and 99.2. Red cells containing Hb Zürich are extremely sensitive to oxidative injury by PAP, either in vivo or in vitro. The degree of oxidative injury diminishes as the level of HbCO increases, a phenomenon that is enhanced by preferential binding of CO to the abnormal beta subunit of Hb Zürich.