Peter Reizenstein

Iron, free radicals and cancer

Free radicals, intermediates in the tissue damage caused by radiation, are formed,inter alia, in interactions catalyzed by iron, which synergizes with radiation and some cytostatics (anthracyclins) in causing cell damage. Conversely, iron chelators can counteract cell damage. Similarly, antioxidants can slow atherogenesis, caused in part by oxidative stress and free radicals. Cell damage is also prevented by physiological defense systems like Superoxide dismutase, against endogenous free radicals formed by granulocytes, monocytes, etc. Iron can thus induce free radicals which cause DNA double strand breaks and oncogene activation. This is suggested by four epidemiological studies suggesting a higher cancer risk in patients with larger iron stores than in those with small iron stores. In addition to its effect on carcinogenesis, iron can also maintain the growth of malignant cells as well as growth of pathogens. Breast cancer cells, for instance, display 5-15 times more transferrin receptors than normal breast tissue. Iron-carrying transferrin is in fact a growth factor. Hyposideremia in patients with cancer or infection is not a paraphenomenon but a functioning defense mechanism (’nutritional immunity’). If this immunity is broken by iron administration, relapses of diseases like tuberculosis, brucellosis, and malaria have been described. While iron-deficiency anemia should of course be diagnosed, treated and if possible prevented, there are good reasons to avoid over-utilization of medicamental iron.

Formation and proliferative effects of lipoxins in human bone marrow.

Lipoxins A4 and B4 together with the all-trans lipoxin (LX) isomers were produced by normal human bone marrow cell suspensions after incubation with ionophore A23187. Both LXA4 and LXB4 enhanced the growth of myeloid progenitor cells in semisolid agar in the presence of suboptimal concentrations of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF). Lipoxin A4 at 10(-10) M stimulated the colony formation in 13 out of 15 tested human bone marrows with a mean (+/- SEM) increase of 47 +/- 11% (p = 0.001). A similar stimulatory effect was observed after addition of LXB4 (10(-10) M). The monohydroxyeicosatetraenoic acids 5-, 12- and 15-HETE did not affect colony growth. In addition, LXA4 (10(-8) M) efficiently counteracted the increased colony formation induced by leukotriene C4 (10(-10) M), suggesting an antagonistic relationship between these lipoxygenase products. The results support a role for lipoxins in the regulation of human myelopoiesis.

Response to Treatment in Acute Non‐lymphatic Leukaemia: Prognostic Value of Colony Forming and Colony Stimulating Capacities of Bone Marrow and Blood Cells Compared to Other Parameters

Growth of bone marrow and mononuclear white blood cells (MWBC) in soft‐agar cultures was studied in 26 patients with untreated acute non‐lymphocytic leukaemia (ANLL). Marrow and MWBC from 30 healthy volunteers served as controls. All ANLL patients revealed an abnormal growth in vitro. Patients with an increased number of clones in marrow cultures and large cluster predominance (‘excessive growth’) responded poorly to therapy with only one of 10 patients entering remission. On the contrary, only two of the 15 patients with a decreased clone number (‘low growth’) failed to achieve remission. The number of colonies and clusters in both bone marrow and blood cultures was significantly lower at presentation in patients who later entered remission than in those who did not. The correlations between the number of colonies and clusters in the blood and the marrow cultures were statistically significant. No significant correlations were found between prognosis or colony formation, on one hand, and the production of colony stimulating activity (CSA), by bone marrow and blood cells of ANLL patients, on the other. Nor could such correlations be found between prognosis, blood cell counts, and age. It is concluded that the growth pattern of both bone marrow and circulating colony forming cells is of value in predicting the response to cytostatic drugs and particularly in selecting patients with a high probability to respond poorly to current cytostatic regimes.

Biliary and fecal vit. B12 excretion in man: an isotope study.

Summary It was attempted to study Vit. B12 excretion in man by investigating the elimination of small doses of parenterally administered radiovitamin Co56-B12. Relatively large amounts of radioactivity were excreted in the bile, feces and urine shortly after injection. After this period, the excretion pattern changed, and radioactivity of relatively constant value was excreted with the bile and feces, indicating that these are the main excretion routes in man, whereas the urine samples exhibited low radioactivity. The fecal radioactivity was only about one-third of the calculated biliary excretion, which indicates intestinal reabsorption of biliary B12. If it were assumed, that the radiovitamin mixes uniformly with the body stores of Vit. B12, it could be estimated that normal subjects may lose considerable amounts of B12 per day, and consequently, the requirement of B12 could be larger than hitherto suspected. The findings may have therapeutical implications.

Oxymetholone treatment in myelofibrosis.

ZusammenfassungDie therapeutische Wirksamkeit von Oxymetholon bei fortgeschrittener Osteomyeloflbrose wurde im Rahmen einer prospektiven Studie geprüft. 11 Patienten (4 Frauen, 7 Männer) erhielten 3–5 mg/kg Körpergewicht Oxymetholon. 5 dieser Patienten hatten vorher eine polyzythämische Phase. Alle Patienten hatten bei Beginn des Therapieversuchs eine Anämie, 4 eine Leukopenie und 10 zusätzlich eine Thrombopenie. Eine Hepatosplenomegalie war immer vorhanden. 5 Patienten benötigten vor Behandlung regelmäßig Bluttransfusionen.In 9 von 15 Therapiephasen wurde eine Normalisierung und deutliche Besserung beobachtet. Die Veränderungen des Hämoglobinspiegels und der Plättchenzahl waren signifikant. 4 Patienten verschlechterten sich nach Dosisreduktion oder bei Absetzen von Oxymetholon; 2 davon sprachen erneut an. Bei einem Patienten kehrten die Werte zu den früher bestehenden polyzythämischen Werten zurück. 1 Patient starb durch eine akute Leukämie.Die Ergebnisse der Studie weisen daraufhin, daß Androgene in weit fortgeschrittenen Fällen von Myelofibrose mit transfusionsbedürftiger Anämie oder schwerer Zytopenie von Wert sein könnte.SummaryIn order to study the effect of oxymetholone therapy in advanced myelofibrosis, 11 patients (4 females, 7 males) were given, 3–5 mg per kg body weight, long-term oxymetholone treatment in a prospective multicenter study. Five cases had previously had a diagnosis of polycythemia vera. All patients had anemia initially, 4 leukocytopenia and 10 thrombocytopenia in addition. Hepato-splenomegaly was present in all cases but in varying degree. Five patients required regular blood transfusions before treatment.In 9 of the 15 courses given, there was normalization of the peripheral blood or substantial improvement (better than 3 g hemoglobin/dl or 50×109 platelets/1) after androgens. Significant effects were noted both on hemoglobin values and platelet counts. The need for blood transfusions ceased completely in all 5 cases. When oxymetholone treatment was reduced or interrupted 4 patients relapsed; 2 of them responded to a renewed course. The red cell counts returned to previous polycythemic values in one patient and another died from acute leukemia.The results of this study suggest that androgens might be of value in advanced cases of myelofibrosis with transfusion-requiring anemia or severe thrombocytopenia.

Elevated white blood cell synthesis of leukotriene C4 in chronic myelogenous leukaemia but not in polycythaemia vera

Leukotriene (LT) formation was studied in ionophore A23187‐stimulated white blood cell (WBC) preparations from patients with chronic myelogenous leukaemia (CML; n=14), polycythaemia vera (PV; n=10) and two control groups consisting of patients with non‐malignant inflammatory disease (n= 4) and normal healthy donors (n= 25). The synthesized products were identified and quantitated using high‐performance liquid chromatography combined with computerized UV‐spectroscopy.

Leukotrienes and lipoxins—New potential performers in the regulation of human myelopoiesis

Leukotrienes and lipoxins are bioactive lipoxygenase products formed by leukocytes alone or in collaboration with other cells. While the physiological role of lipoxins remains to be clarified, accumulating evidence shows that leukotrienes are important mediators in asthma and inflammation. Consequently, recent clinical trials with leukotriene D4 receptor antagonists and 5-lipoxygenase inhibitors have demonstrated marked reduction of airway symptoms in asthmatic patients. In addition, both leukotrienes and lipoxins have been indicated as modulators of cell proliferation. This article reviews recent findings suggesting that these compounds may also participate in the regulation of human myelopoiesis. Such a role is conceivable since leukotrienes and lipoxins can be produced by bone marrow cells and potently modulate GM-CSF-induced myeloid stem cell proliferation.

Resistance of leukemic blasts to lymphokine activated killer (LAK)-mediated cytotoxicity is not related to their adhesion properties

Abstract: The expression of adhesion molecules on blasts from 14 patients with acute myeloid leukemia (AML) was investigated by immunofluorescence and flow cytofluorometry. All tested blast populations expressed CD18/CDlla complex {leukocyte function antigen‐1 (LFA‐1)} and CD29 (very‐late antigen (VLA)) and the majority were positive for CD54 {intercellular adhesion molecule‐1 (ICAM‐1), 78.6%} and CD56 {neural cell adhesion molecule (NCAM), 64.3%}. The expression of two other alpha chains of CD18/CDllb and CDllc varied considerably (64.3% and 42.8% of positive cases, respectively). Only one case (AML‐M4) showed a weak expression of the activated platelet antigen CD41b. None of the tested blasts expressed the vitronectin receptor (CD61/CD51). No significant correlation between the expression of adhesion molecules and the FAB type of leukemia could be found. All tested blast populations were completely resistant to NK‐mediated cytotoxicity and relatively resistant to LAK‐mediated cytotoxicity in the standard 51Cr release assay. While no statistically significant correlation of the results in cytotoxicity assays with the expression of adhesion molecules or the expression of HLA‐DR antigen could be observed, 2 out of 3 completely resistant cases lacked ICAM‐1. These results show that even leukemic blasts which express all of the tested adhesion molecules can still be resistant to LAK‐mediated cytotoxicity.

Oxymetholone Treatment in Hypoproliferative Anaemia1

45 patients with hypoproliferative or aregenerative anaemia were treated with oxymetholone, steroid an anabolic, androgenic steroid. Minimum treatment time accepted for entrance into the study was 3 months. Therapeutic effect was assessed by effect on bone marrow cellularity, haemoglobin concentration and granulocyte and platelet counts. Patients with a hypocellular marrow responded best. Of 18 cases, a partial remission was seen in 8 and a complete remission in 5. A complete remission was only seen in patients who did not have pancytopenia. Of the 7 patients with myelofibrosis, 4 had thrombocytopenia at the outset. Improvement after treatment was seen in all 4. The only serious side-effect that necessitated withdrawal of treatment was jaundice.

Effects of immunotherapy and chemotherapy on immunocompetence. A study of patients with acute myeloblastic leukemia in remission

SummaryThe immunocompetence of 33 patients with acute myeloblastic leukemia in remission and treated with cytostatics (CT) was studied. In addition to cytostatics some of the patients were given immunotherapy (CT+IT).In an attempt to demonstrate immunization against allogeneic leukemic blast cells (or their extracts) or immunostimulation after immunotherapy or, alternatively, immunodepression after maintenance chemotherapy without immunotherapy, delayed hypersensitivity tests and lymphocyte stimulation tests were performed. In most cases PHA seemed to be a stronger stimulator than allogeneic lymphocytes and these seemed to be stronger than allogeneic blasts, although no difference was statisically significant.No significant differences were found in vitro or in vivo between the reactions of CT and CT+IT patients or their lymphocytes to allogeneic myeloblasts or to allogeneic lymphocytes. However, numerically, in vitro and in vivo CT+IT patients reacted more to myeloblasts, CT patients more to lymphocytes. This could suggest antigens on leukemic myeloblasts that are not found on lymphocytes. With present methods we could demonstrate neither immunodepression in patients given only chemotherapy nor nonspecific immunostimulation after immunotherapy. There was no significant difference between the two treatment groups in lymphocyte reactivity against PHA and allogeneic lymphocytes. Nor was the lymphocyte reactivity different from that in a group of healthy persons.Decreasing lymphocyte reactivity to PHA and allogeneic lymphocytes seemed to herald relapse.