Deferoxamine inhibition of malaria is independent of host iron status.

The mechanism whereby deferoxamine (DF) inhibits the growth of malaria parasites was studied in rats infected with Plasmodium berghei. Peak parasitemia was 32.6% (day 14) in untreated controls and 0.15% (day 7) in rats receiving 0.33 mg/g in 8 hourly DF injections, subcutaneously. DF inhibition of parasite growth was achieved without any reduction in transferrin saturation or hemoglobin synthesis and with only a partial (56%) depletion of hepatic iron stores. Dietary iron depletion resulted in anemia (hematocrit 25 vs. 46%), microcytosis (MCV 54 vs. 60 fl), and reduced transferrin saturation (17 vs. 96%) without any effect on infection (peak parasitemia 30 vs. 36%). Similarly, parenteral iron loading with ferric citrate over 10 d (75 mg iron/kg) failed to aggravate infection. In a search for evidence of direct interaction between DF and parasitized erythrocytes, gel filtration and ultrafiltration was performed on hemolysates obtained from in vivo 59Fe-labeled parasitized erythrocytes. This showed that 1.1-1.9% of the intracellular radioiron was located in a chelatable, labile iron pool. Incubation of intact cells with 0-500 microM DF resulted in a proportional increase in intracellular iron chelation, and the chelation of all available labile intracellular iron was completed within 6 h. These observations indicate that the severity of P. berghei infection in rats and its in vivo suppression by DF are independent of host iron status and suggest that DF inhibition of malaria involves intracellular chelation of a labile iron pool in parasitized erythrocytes.

[Conclusions and recommendations of a WHO expert consultation meeting on iron supplementation for infants and young children in malaria endemic areas]. / Conclusions et recommandations à l'issue de la consultation de l'OMS sur la lutte contre la carence martiale chez le nourrisson et le jeune enfant dans les pays d'endémie palustre.

This article presents the results of an expert consultation meeting aimed at evaluating the safety and public health implications of administering supplemental iron to infants and young children in malaria-endemic areas. Participants at this meeting that took place in Lyon, France on June 12-14, 2006 reached consensus on several important issues related to iron supplementation for infants and young children in malaria-endemic areas. The conclusions in this report apply specifically to regions where malaria is endemic.

Recurrent Neisseria meningitidis bacteremia. Association with deficiency of the eighth component of complement (C8) in a Sephardic Jewish family.

A 24-year-old man had repeated episodes of meningococcal meningitis. Selective deficiency of the eighth component of complement (C8) was demonstrated in the patient, his twin brother, and in one of five siblings. As the parents were first cousins of normal phenotype, this pattern is suggestive of an autosomal recessive heredity. The present report brings the total number of patients given the diagnosis of C8 deficiency to 14, and calls attention to the existence of this condition in Jews of Sephardic (Mediterranean) origin.

Identification of community flour mills as the source of lead poisoning in West Bank Arabs.

Following the discovery of severe lead poisoning in members of several households in a West Bank village, studies were carried out to establish the magnitude of the problem in the community and to identify the source of lead poisoning. Forty-three patients with Centers for Disease Control risk group IV lead poisoning were identified and treated in three villages within a radius of about 10 km of each other. The prevalence of increased lead burden among 563 schoolchildren aged 10 to 18 years was 19% for Centers for Disease Control risk groups I and II and 11% for groups III and IV. A survey of potential sources excluded all items, except for locally ground flour, which was heavily contaminated in all affected households. Examination of community flour mills revealed that, in contrast to unprocessed grain, freshly ground flour contained large amounts of lead originating from lead fillings employed to fasten the housing of the driveshafts to the millstones. Systematic screening of 146 community stone mills in 92 West Bank villages showed significant lead contamination of flour in 33 mills (23%). In all cases, the source of lead contamination was identical. As methods of milling in the area are similar, a prompt investigation of this potential source of lead poisoning in other near-Eastern countries is indicated.

Lead poisoning in a West Bank Arab Village.

Eleven patients from the West Bank village of Es-Sawiyeh were admitted with lead poisoning to two Jerusalem hospitals between November 1982 and January 1983. They all belonged to several households of a single large family. Colicky abdominal pains were present in five patients, weakness in four, behavioral changes ranging from irritability to frank psychosis in four, and paralysis in one. Anemia of various degrees was seen in all patients. Basophilic stippling and reticulocytosis were encountered in all patients with moderate to severe anemia. Therapy with edetate disodium calcium and penicillamine resulted in clinical improvement in all patients. A preliminary survey of 270 subjects in the same village disclosed 84 subjects with abnormally elevated blood lead levels, 17 of whom had grade IV lead burden according to the Centers for Disease Control risk classification. Contamination of homemade flour by lead used for stabilizing the metal parts of stone mills was the source of poisoning. As the method of milling in many West Bank villages is similar, these findings may have important implications to the well being of a large section of the rural West Bank population.

[Lead poisoning by contaminated flour: an unfinished story].

A young Arab woman was diagnosed with severe lead poisoning in the early 80's. Detailed epidemiologic studies revealed many additional cases of lead poisoning in the rural population south of Nablus and a population survey conducted among schoolchildren revealed increased blood lead levels in 30% of the children. The source of poisoning was contamination from home-made flour by lead fillings used to secure the housing of the driveshaft to the millstone. Of the 146 village mills surveyed, lead concentrations in freshly ground flour exceeding 1.5 ppm were found in 8% of the mills. Following our original report, identical outbreaks caused by contaminated flour were reported from Spain, Turkey, Greece and Albania. In spite of administrative efforts to prevent the use of lead in flour mills, the problem still persists. In Israel itself, similar subsequent outbreaks have been documented in the Upper Galilee, and recently in the Hebron district. Apparently, the problem has existed since antiquity because flour mills employing lead parts were introduced to this and other countries during the Roman conquest. A coordinated international effort is essential to eliminate this unique and serious health threat from the environment.

In vitro bioassay of erythropoietin using synchronized rabbit erythroid precursors.

Synchronized erythroid precursors obtained from the bone marrow of rabbits and plated in methyl-cellulose were used as a bioassay for the measurement of erythropoietin (Ep). Rabbits were given five daily injections of phenylhydrazine followed by a single dose of actinomycin-D. This treatment resulted in a rapid repopulation of bone marrow by synchronized erythroid precursors which can be stored at -180 degrees C for long periods. Grown in vitro for 2 days in the presence of added Ep these cells divided to form colonies (CFUE). The erythroid nature of these colonies was confirmed by 59Fe incorporation into heme. Preliminary studies indicate that this system is suitable for the measurement of Ep in human sera. It is simple, inexpensive, reproducible, and permits measurements at the physiologic range of Ep concentrations.

Autologous bone marrow transplantation in patients with cancer.

Ten patients with non-leukemic neoplasms received intensive, marrow-lethal doses of drugs and radiation followed by rescue with autologous cryopreserved bone marrow (nine) or marrow from an identical twin as part of a phase 1-2 study. Nine patients had extensive disease that was unresponsive to conventional therapy. Marrow engraftment was documented in all evaluable cases and most patients had a substantial anti-tumor response. Three patients are alive from 4 to 10 months following transplantation without evidence of disease.

Iron chelation.

Adequate iron chelation in thalassaemia has resulted in a striking improvement in survival, with a reduction of cardiac mortality at age 15 years from 14-3%, and a predicted survival at age 36 years of 85%. Long term desferrioxamine (DF) therapy in thalassaemic children should be started between 2-4 years of age. In addition to daily 8-12 h subcutaneous infusions, intermittent high dose (9-16 g) i.v. supplementation over 24-48 h may be given on the occasion of blood transfusions. In established myocardiopathy continuous i.v. DF infusion at 100-125 mg/kg/d may result in improved myocardial function. In addition, there is considerable current interest in the use of DF in conditions unrelated to iron overload by preventing the formation of free-radicals in inflammatory reactions, or by S-phase inhibition of cell proliferation. Although at present highly experimental, this novel approach may have important implications for the management of patients with inflammatory conditions and perhaps in the control of protozoal infections. Over the last decade several hundred candidate compounds have been studied in cell cultures and in animal models and a number of orally effective iron chelators have been identified, all of which are superior to DF in their in vivo iron chelating effect. Although we do not yet have a new drug which is immediately available for replacing DF in clinical practice, significant progress has already been made, and some of the most promising candidate drugs are currently undergoing extensive toxicity tests in anticipation of their development for large-scale clinical use.

The changing pattern of megaloblastic anemia: megaloblastic anemia in Israel.

The causes of megaloblastic anemia were studied in a survey of patients admitted to six Israeli hospitals over a period of 15 yr. Among the 203 patients identified, 69% had pernicious anemia, 12% had gastrointestinal disease, 9% had primary nutritional deficiency of whom only 1% were associated with pregnancy, and 7% had selective vitamin B12 malabsorption with albuminuria. Comparison with previously published surveys showed, that in contrast with earlier studies where primary nutritional deficiency was the cause of megaloblastic anemia in about 70% of cases and pernicious anemia in only 20%, in more recent studies the proportion of cases with primary nutritional anemia in general and those associated with pregnancy in particular was much lower. This is most probably the result of improved standards of living and a national program of preventive folate supplementation at maternity clinics. A potential hazard of such preventive programs is the aggravation of neurological complications in patients with undiagnosed vitamin B12 deficiency. Early recognition of pernicious anemia and other forms of selective B12 malabsorption is a new challenge created by the changing pattern of megaloblastic anemias.

Serum and erythrocyte folates in combined iron and folate deficiency.

A high incidence of iron and folate deficiency was found in 80 female subjects living in a private institution. Iron therapy in individuals with low serum iron values resulted in a significant increase in hemoglobin levels. An improvement in serum and RBC folate levels was also found following iron therapy but this could not be attributed to treatment since a similar increase was observed in untreated control subjects, probably due to an increased dietary intake of folates during the study period. In subsequent studies small amounts of pteroylglutamic acid were given to all patients and their response to therapy was related to initial serum and RBC folate values. No correlation between serum folate levels and response to folate therapy could be demonstrated. Red cell folate levels on the other hand correlated well with response to therapy. A significant increase in hemoglobin was found following folate therapy in patients with low RBC folates, but not increase in subjects with normal RBC folates. Conversely, the increase in hemoglobin following iron therapy in subjects with normal RBC folates was three times as much as in patients with low RBC folates. Thus, unlike serum folate determinations, RBC folate measurements are a reliable index of tissue folate stores, and useful in the prediction of response to folate therapy in both the iron-deficient and iron-replete states.

Diagnosis of iron deficiency anemia in a rural population of children. Relative usefulness of serum ferritin, red cell protoporphyrin, red cell indices, and transferrin saturation determinations.

The diagnostic usefulness in iron deficiency anemia of serum ferritin, red cell protoporphyrin (Epp), mean corpuscular volume, mean corpuscular hemoglobin (MCH), and transferrin saturation measurements has been studied in a population of 294 children aged 1 to 6 yr. Of the children studied 19% had hemoglobin below 11 g/dl. Iron deficiency, diagnosed by at least two abnormal independent laboratory parameters, was the cause of anemia in all except two cases. The Pearson correlation coefficient for hemoglobin was highest with MCH, followed in decreasing order of magnitude by MCV, Epp, transferrin saturation, and finally by ferritin. Sensitivity and specificity were highest for MCH and lowest for ferritin. Of anemic, iron deficient individuals 97 to 100% could be identified by low MCH, 88 to 100% by transferrin saturation, 66 to 83% by ferritin, and 61 to 74% by Epp. In contrast, only 0 to 6% of normal, nonanemic individuals had low MCH, 0 to 4% had high Epp, but 21 to 39% had low transferrin saturation and 25 to 39% had low ferritin. Although reduced serum ferritin in anemic individuals is good evidence of iron deficiency, a significant proportion of anemic iron-deficient patients is missed by this procedure rendering it less useful than other, less expensive laboratory methods.

A rapid and sensitive ELISA for serum ferritin employing a fluorogenic substrate.

A fluorescent enzyme-linked immunosorbent assay is described for the rapid measurement of serum ferritin. Increased sensitivity was achieved by using 4-methyl-umbelliferyl-beta-D-galactopyranoside as the substrate for beta-galactosidase coupled to the purified antiferritin antibody. Further enhancement of the specific antigen-antibody reaction was attained by the addition of 4% polyethylene glycol 6000 to the antiferritin-beta-galactosidase conjugate. The procedure is performed in microELISA plates. These modifications of the method permit the measurement of serum ferritin at concentrations ranging from 0.25 to 50 microgram/liter with a coefficient of variation of 8% or less. The entire procedure is performed at ambient temperature and is completed within one working day. The cost of the assay is less than 10% of the immunoradiometric assay for serum ferritin.

Syntheses of iron bis(pyridoxal isonicotinoylhydrazone)s and the in vivo iron-removal properties of some pyridoxal derivatives.

Pyridoxal isonicotinoylhydrazone (PINH; 1) and its isomeric O-acetates (E and Z) were synthesized and complexed with ferrous ions to afford the hitherto unisolated chelates iron(II) bis(pyridoxal isonicotinoylhydrazone)s (11) and iron(II) bis(O-acetylpyridoxal isonicotinoylhydrazone)s (12). The analytical and spectroscopic data of the new coordination compounds are presented. In addition, a series of imino derivatives of pyridoxal of structures 2-3 and 5-10 have been prepared and tested in vivo as chelators of storage iron, and the cumulative net excretion of radioiron in urine and in feces was estimated. This study reestablishes that PINH is a potent iron chelator in vivo comparable in efficiency with parenteral desferrioxamine (DF) and indicates that it requires further attention.

Inhibition of calcium accumulation by the sarcoplasmic reticulum: a putative mechanism for the cardiotoxicity of adriamycin.

The aim of this study was to examine the effect of adriamycin (ADR) on calcium accumulation by the sarcoplasmic reticulum (SR). Chemical skinning of cultured rat myocardial cells compromised the barrier function of the cell membrane and thus permitted direct exposure of mitochondrial and non-mitochondrial sites to ADR. In the presence of ATP, and sodium azide, mitochondrial calcium accumulation was negligible. Furthermore, it has previously been shown that non-mitochondrial calcium accumulation is mediated mainly by the SR under these conditions. Incubation with 10 microM ADR for 2 hr reduced the level of calcium accumulation by the SR by 50%. A similar effect was obtained after 24 hr incubation with 1 microM ADR. The addition of ferric iron to the culture medium further reduced the level of calcium accumulation. Neither vitamin E nor beta-carotene affected calcium accumulation by the SR. These results suggest that ADR interferes with the calcium accumulation activity of the SR and that ferric iron potentiates this effect.

Disseminated intravascular coagulation and hypopotassemia associated with blast lung injury.

Forty six people were injured by a large explosive charge detonated in a Jerusalem bus. Four were killed instantaneously and 22 needed hospital care. We describe our experience in five patients with blast lung injury (BLI), all of whom survived in spite of severe respiratory failure requiring mechanical ventilation. Disseminated intravascular clotting (DIC) developed in three of the five patients and significant hypopotassemia ranging from 2.2 to 2.9 mEq/L in four. These two complications have not been previously described in association with BLI. Both DIC and hypopotassemia responded to replacement therapy. Vigorous treatment of respiratory failure, early recognition, and prompt correction of hemostatic and electrolyte abnormalities may have contributed to the avoidance of fatalities among the five patients with severe blast injury.

Pathophysiology of iron overload.

In thalassemia, iron overload is the joint outcome of excessive iron absorption and transfusional siderosis. While iron absorption is limited by a physiologic ceiling of about 3 mg/d, plasma iron turnover in thalassemia may be 10 to 15 times normal, caused by the wasteful, ineffective erythropoiesis of an enormously expanded erythroid marrow. This outpouring of catabolic iron exceeds the iron-binding capacity of transferrin and appears in plasma as non-transferrin-plasma iron (NTPI). The toxicity of NTPI is much higher than of transferrin-iron as judged by its ability to promote hydroxyl radical formation resulting in peroxidative damage to membrane lipids and proteins. In the heart, this results in impaired function of the mitochrondrial respiratory chain and abnormal energy metabolism manifested clinically in fatal hemosiderotic cardiomyopathy. Ascorbate increases the efficacy of iron chelators by expanding the intracellular chelatable iron pool, but, at suboptimal concentrations is a pro-oxidant, enhancing the catalytic effect of iron in free radical formation. NTPI is removed by i.v. DFO in a biphasic manner and reappears rapidly upon cessation of DFO, lending support to the continuous, rather than intermittent, use of chelators. Unlike DFO and other hexadentate chelators, bidentate chelators such as L1 may produce incomplete intermediate iron complexes at suboptimal drug concentrations.

The haematologist as watchdog of community health by full blood count.

Although full blood counts (FBC) are among the most commonly performed laboratory tests, the contribution of routine FBCs to the diagnosis of new problems is controversial. This study represents a unique linkage of a consultant haematology team, reviewing all abnormal blood counts, to an organization providing ambulatory health care to 350,000 patients. The objective was to establish the underlying clinical disorders responsible for all abnormal FBCs during a 2-month period, and to estimate the impact of the haematology team on the diagnostic work-up and management of newly identified problems. 572 (2.55%) of the 22,454 FBCs were abnormal. Of these, 357 showed microcytosis, caused by iron deficiency (58%), thalassaemia minor (35%), inflammation (6%) or chronic renal failure (1%). The most common causes of normocytic anaemia (25 patients) were disseminated malignancy and acute blood loss; of macrocytosis (27 patients), chronic liver disease and cancer; of erythrocytosis (16 patients), chronic hypoxia; of thrombocytopaenia (48 patients), chronic liver disease and ITP; of thrombocytosis (47 patients), iron deficiency and inflammation; of leukopaenia or pancytopaenia (20 patients), cirrhosis and disseminated malignancy; and of leukocytosis (26 patients), chronic leukaemias in the elderly and infection in children. Major new haematological abnormalities were encountered in 0.24% of all blood counts, representing about one new diagnosis per day. Routine blood counts do contribute to the health care of a population. Screening for haematological disease through a central clinical laboratory covering a large high-risk ambulatory population offers a cost-effective way of searching for serious clinical problems, alerting the primary physicians of their existence, and offering advice in continued evaluation and problem management.

The role of iron and iron chelators in anthracycline cardiotoxicity.

The redox cycling of anthracyclines promotes the formation of free radicals which are believed to play a central role in their cardiotoxicity. A number of observations indicate that the mechanism of the antineoplastic effect of anthracyclines is independent of their cardiotoxic effect and that it may be possible to prevent toxicity without interfering with therapeutic effect. Iron plays an important role in anthracycline toxicity by promoting the conversion of superoxide into highly toxic hydroxyl radicals through the Haber-Weiss reaction. Conversely, iron deprivation by its high-affinity binding to iron chelating compounds may inhibit anthracycline toxicity by interfering with free radical formation. ICRF-187, a bispiperazonedione which is hydrolyzed intracellularly into a bidentate chelator resembling EDTA, is able to decrease adriamycin-induced free hydroxyl radical formation and to prevent the development of clinical cardiac toxicity in patients receiving long-term anthracycline therapy. Our studies in rat heart cell cultures have shown that iron overload aggravates anthracycline toxicity and that this interaction can be prevented by prior iron chelating treatment. Since iron overload caused by multiple blood transfusions and bone marrow failure is a common condition in patients requiring anthracycline therapy, these observations may have significant clinical implications to the prevention of anthracycline cardiotoxicity.

Reversible central nervous system dysfunction in folate deficiency.

An epileptic patient on chronic anticonvulsant drug therapy is described, in whom anaemia and neurological abnormalities including progressive dementia, bilateral pyramidal tract signs, incontinence and ataxia developed. Vitamin B12 serum levels and absorption were normal, but serum folic acid levels were low. Both the neurological disturbances and anaemia resolved following oral folic acid administration. This sequence of events in our patient suggests a cause and effect relationship between the folate deficiency and the coexistent, transient neurological syndrome.