Zinc and selenium status in pediatric malignant lymphomas.

Ninety-six untreated patients with malignant lymphoma (ML), 81 Hodgkin's disease, and 15 Burkitt's lymphoma were studied for zinc (Zn) status, and 21 patients also had selenium (Se) status analysis. Plasma and hair Zn and Se levels were measured by atomic absorption spectrophotometry. Chronic Zn and Se deficiencies (low plasma and low hair Zn and Se levels together) were found to be associated with ML in Turkish children. This was most likely due to the poor "nutritional environment" of the patients because majority of the ML patients were from families of low socioeconomic status. Supplementation of pediatric ML patients with Zn and Se, in addition to standard chemotherapy and radiotherapy regimen, is recommended.

Ceramide-induced killing of normal and malignant human lymphocytes is by a non-apoptotic mechanism.

Synthetic ceramides induce apoptotic death of Jurkat and HL60 leukaemia cell lines. By contrast we show here that ceramide induces non-apoptotic killing of malignant cells from patients with B-chronic lymphocytic leukaemia (B-CLL) and of normal B lymphocytes. The protein phosphatase inhibitor okadaic acid readily induces apoptosis of B-CLL cells, indicating that this death pathway is fully functional in these cells. The ability of ceramide to activate the apoptotic protease caspase 3 in HL60 cells but not in B-CLL cells, as well as the lack of correlation of ceramide-mediated killing of different B-CLL isolates with expression of the apoptosis-regulating proteins bcl-2 and bax reinforce the conclusion that ceramide killing of B-CLL cells is by a non-apoptotic mechanism. Fludarabine treatment or gamma-irradiation of B-CLL cells resulted in ceramide elevation and in killing by both apoptotic and non-apoptotic mechanisms, suggesting that a ceramide-triggered non-apoptotic mechanism may play a role in the killing of these cells. Therefore, the results here show that ceramide can induce either apoptotic or non-apoptotic death, depending on the cellular context. The inability of synthetic dihydroceramide to kill B-CLL cells or normal B lymphocytes suggests that non-apoptotic killing by ceramide is via interaction with a specific, but unidentified, cellular target.

Herbimycin A accelerates the induction of apoptosis following etoposide treatment or gamma-irradiation of bcr/abl-positive leukaemia cells.

Philadelphia chromosome (Ph)-positive leukaemia cells express the chimeric bcr/abl oncoprotein, whose deregulated protein tyrosine kinase (PTK) activity antagonizes the induction of apoptosis by DNA damaging agents. Treatment of Ph-positive K562, TOM 1 and KCL-22 cells with etoposide for 2d induced cytosolic vacuolation, but not nuclear condensation or DNA fragmentation. The bcr/abl kinase-selective inhibitor herbimycin A increased the induction of nuclear apoptosis by etoposide or gamma-radiation. The concentration of herbimycin required to synergize with etoposide was similar to that required to decrease the level of tyrosine phosphorylated proteins or of the protein tyrosine kinase activity of anti-abl immune complexes in K562 cells. The ability of herbimycin A to sensitize K562, TOM 1 or KCL-22 cells to apoptosis induction correlated with its ability to decrease the cellular content of phosphotyrosyl proteins in these Philadelphia-positive lines. Enhancement of nuclear apoptosis by herbimycin was not attributable to downregulation of the bcl-2 or bcl-XL anti-apoptotic proteins. In contrast, herbimycin protected Philadelphia-negative HL60 cells from apoptosis induction by etoposide and did not affect killing of NC37 and CEM cells. The data suggest that the induction of apoptosis is blocked in cells expressing the bcr/abl oncoprotein and that herbimycin A increases induction of programmed cell death following DNA damage. Selective PTK inhibitors may therefore be of value in securing the genetic death of Ph-positive leukaemia cells.

Inactivation of calcium ion-regulating inositol polyphosphate second messengers is impaired in subpopulations of human leukemia cells.

Inositol 1,4,5-triphosphate (IP3) and inositol 1,3,4,5-tetrakisphosphate (IP4) are calcium-regulating second messenger molecules generated following the binding of a wide range of hormones and growth factors to their receptors. The actions of these messengers, which play important roles in the regulation of cell proliferation as well as in other signaling pathways, are terminated by the action of a 5-phosphomonoesterase (5-PME) enzyme. We have assayed this enzyme in normal and malignant hemopoietic cells. Extracts from normal bone marrow cells and peripheral blood mononuclear cells (PBMNC) degraded [3H]IP3 at rates of 74.5 (+/- 3.4) and 84.5 (+/- 7.9) pmol/min/micrograms protein, respectively. PME activity in 10/13 (77%) acute lymphoblastic leukemia samples were significantly below the normal range and the enzyme was completely undetectable in three (23%) of these. Enzyme activity in 8/9 (89%) chronic lymphocytic leukemia samples were below the normal range, being undetectable in three of these (33%). Nine of 24 (38%) acute myeloid leukemia samples contained low 5-PME levels, which was undetectable in one sample. Reduced 5-PME activity was detected in 2/7 (28%) of chronic granulocytic leukemia samples. The data here are consistent with the hypothesis that a reduced rate of degradation of IP3 and IP4 in some leukemia cells may result in the aberrant operation of signaling pathways, possibly including those involved in the control of cell proliferation.

Co-ordinated downregulation of bcl-2 and bax expression during granulocytic and macrophage-like differentiation of the HL60 promyelocytic leukaemia cell line.

The bcl-2 protein suppresses apoptosis and the bax protein opposes the cytoprotective effect of bcl-2. A decrease in bcl-2 levels has been implicated in the induction of apoptosis during the terminal differentiation of HL60 myeloid leukaemia cells. We show here that bax protein also declined with a time course similar to the downregulation of bcl-2 following treatment of HL60 with phorbol myristate acetate (PMA), dimethyl sulphoxide (DMSO) or retinoic acid (RA). Decreased bcl-2 protein expression in induced cells was associated with down-regulation of its mRNA. By contrast, the decrease in bax occurred by a post-transcriptional mechanism. Co-ordinate downregulation of bcl-2 and bax proteins may fine-tune the induction of apoptosis during cellular differentiation.

Late effects of chemoradiotherapy in pediatric Hodgkin's disease.

We treated 137 Turkish children with biopsy-proven Hodgkin's disease, followed up between the years 1964 and 1989. Most patients were treated and were in advanced stage with histological subtype of mixed cellularity (67.5%). Radiotherapy (Mantle form) and/or MOPP, ABVD and OPPA combination chemotherapy regimens were used in 75.84% of patients. The follow-up period in these patients ranged from 5 to 24 years. The late effects in 28 patients who were evaluated for the late sequelae of chemoradiotherapy are presented. Seven out of 28 patients showed retarded sexual maturation. Testicular and ovarian functions were assessed in 11 patients, all of whom showed elevated serum FSH levels and 2 azoospermia. Analysis of thyroid functions was carried out in patients receiving radiotherapy to the neck. The thyroid gland was palpable in 6 patients. Further analysis showed diffuse hyperplasia in 5 and nodular in 1 patient. The nodule was excised and reported as "nodular colloidal goiter". Two patients had elevated TSH levels. "Swan-like neck" was observed in 3 patients who had received 40 to 42 Gy radiotherapy to the neck. Cirrhosis due to chronic hepatitis B infection was diagnosed in 2 patients as an unusual late complication. The secondary malignancy occurred in only 1 case in the form of "fibrosarcoma". The second neoplasm was probably radiation-induced as it occurred in the field of prior radiotherapy.

Selenium status of healthy Turkish children.

Selenium concentrations, in blood plasma, red blood cells, hair of 61 healthy children, ages 0-14 yr, were determined using hydride generation atomic absorption spectrometry. Starting from late lactation period, selenium concentrations in all these matrices were found to be increasing with age. A good correlation was found between erythrocyte and plasma, hair and plasma, and hair and erythrocyte selenium concentrations. Although plasma, erythrocyte, and hair selenium concentrations of girls seemed to be higher than that of boys (only in erythrocytes), selenium concentrations of girls were found to be significantly (p < 0.002) higher than that of boys, 71 +/- 9 ng/mL, vs 65 +/- 10 ng/mL, respectively. Selenium status of Turkish children is found to be lower than that found in the literature; marginal selenium deficiency could be important in the development of some selenium deficiency related diseases. There is a need for extension of this study to healthy children from different regions in Turkey and to different disease states.

Trace Element Analyses (Zinc and Selenium) in Pediatric Malignant Lymphomas.

Ninetysix untreated patients with Malignant lymphoma's, 81 Hodgkin's disease and 15 Burkitt's lymphoma were studied for zinc (Zn) and selenium (Se) status. Plasma and hair Zn, and Se levels were measured by atomic absorption spectrophotometry. Chronic Zn and Se deficiencies (low plasma and low hair Zn and Se levels together) were found to be associated with Malignant lymphoma's in Turkish children. This was most likely due to poor "nutritional environment" of the patients since majority of the Malignant lymphoma cases were from low socioeconomic class. Supplemention of the patients with physiological doses of Zn and Se, in addition to standard chemo radiotherapy regimen was proposed.

Hepatoma with right atrial extension.

The case is described of a 14-year-old boy who had a hepatoma with a right atrial extension. He presented with edema, abdominal pain, and ascites. Two-dimensional echocardiography showed a right atrial tumor that had invaded from the inferior vena cava as an extension into the right atrium of the hepatoma.

Killing of T lymphocytes by synthetic ceramide is by a nonapoptotic mechanism and is abrogated following mitogenic activation.

Ceramide induces apoptosis in leukemia cell lines and has been proposed as a potential therapeutic agent in malignancies refractory to conventional treatment. Here we show that synthetic N-acetyl-d-erythro-sphingosine (C2 ceramide) kills normal human T lymphocytes by a caspase-independent nonapoptotic mechanism. By contrast, T cells were induced to caspase-dependent apoptosis by okadaic acid. Furthermore, C2 ceramide treatment of the Jurkat leukemia cell line induced killing by apoptosis. Activation of T lymphocytes by phytohemagglutinin abrogated killing by C2 ceramide. The data here suggest that ceramide triggers caspase-dependent apoptosis in leukemia cells lines, but activates caspase-independent nonapoptotic killing of resting T lymphocytes which is abrogated following mitogenic activation.