To evaluate the role of calcineurin (protein phosphatase type 2B, PP2B) in methylprednisolone-induced differentiation and apoptosis of leukaemic cells, we have investigated the induction of apoptosis, calcineurin specific protein phosphatase activity and expression of regulatory and catalytic subunits of calcineurin and calmodulin after induction of HL-60 leukaemic cells with methylprednisolone. The cells underwent differentiation and apoptosis within 72 hours time period after methylprednisolone added to cell culture media. Before apoptosis occurred, the specific calcineurin enzyme activity revealed gradual increase during the differentiation process. However, immunoblots of catalytic and regulatory subunits of calcineurin showed no amplification in the amount of these cellular signaling mediators during methylprednisolone-induced differentiation and apoptosis but calmodulin expression gradually increased during the process. Significant increase in the specific calcineurin enzyme activity during differentiation and apoptosis might be crucial to the posttranslational modifications of calcineurin during methylprednisolone-induced differentiation.

CXCR4 is the receptor of CXC chemokine SDF-1 and may play a role in the homing of hematopoietic stem cells. We have investigated the CXCR4 gene expression during ATRA treatment in acute promyelocytic leukaemia (APL) patients. APL is a characteristic disorder with a specific translocation between PML and RAR alpha genes on chromosome 15 and 17. ATRA-induced differentiation of APL cells is strictly dependent on the presence of PML-RAR alpha. In our study, five APL patiens were involved. Two samples from each patient were compared to each other: Primary diagnostic sample and a sample taken at remission. Quantitative real-time PCR (LightCycler) has been used for quantification, which is a recently developed method for rapid and sensitive detection of gene expression. CXCR4 gene ratios were found under-expressed in cases 1 and 6 with blast counts at diagnosis 18%, and 20% but only moderately under-expressed in cases two and four where the blast count was at diagnosis 50%, and 80%. It was over-expressed only in case three where the blast count was 95%. These findings indicate that ATRA treatment might be effective in CXCR4 gene expression related to amount of the blast population in APL. Further gene expression studies would be helpful to understand how ATRA works on CXCR4 related molecular pathways in APL pathogenesis.

Hemoglobin Pyrgos [ß83 (EF7) Gly→Asp] is a rare hemoglobin variant. This report describes the first observation of this variant in an 18-year-old Turkish girl living in Isparta.

Thrombotic thrombocytopenic purpura (TTP) typically presents with consumptive thrombocytopenia, non-immune intravascular hemolytic anemia, renal failure, various neurologic findings and fever. It is a clinical syndrome that can be associated with drugs such as ticlopidine, quinine, mitomycin C and cyclosporine, allogeneic stem cell transplantation, pregnancy, infections, autoimmune diseases and metastatic carcinoma. Here, we describe a 48-years- old women presented with full picture of TTP and diagnosed as leiomyosarcoma with further evaluation. She was successfully treated with multiple exchange transfusions and total excision of leiomyoma thereafter. As far as we know, this is the first case of leiomyosarcoma of the uterus presented with TTP. Therefore, the women with TTP, in whom no other cause can be found, should undergo a careful gynecological examination and pelvic ultrasonography should be performed.

Hypercalcemia is common in some lymphoproliferative disorders such as myeloma or T- cell leukaemialymphoma, but is rarely described in B-cell chronic lymphocytic leukaemia (CLL). A CLL patient who have been presented with multiple pathological fractures and widespread osteolytic lesions is reported. He was a 74 year old male with fractures of his bilateral humerus and radii and multiple osteolytic lesions of skull, fibula, femur and costals. On his admission to the hospital for the fractures he has been diagnosed as CLL. Hypercalcemia has also been documented. All the disorders that could be the reason of hypercalcemia have been ruled out. The open biopsy of bone marrow showed lymphocytic infiltration in which increased number of prolymphocytes are observed. Hypercalcemia arising in a patient with CLL may indicate a negative prognosis.

Immunosuppression is a risk factor for the development of posttransplant lymphoproliferative disorder. This type of malignancy developed in an immunocompromised man. The patient presented with focal convulsion starting from right face and right arm followed by two generalized convulsions with one minute interval. Diagnosis was made by computed tomographic (CT) scan of the cranium following oral and intravenous administration of contrast dyes which revealedmass leisons in the frontotemporal lobe and by stereotaxic biopsy. Tissue sections showed a malignant tumor cell infiltration with large areas of necrosis and many mitoses. Many tumor cells were positive for CD 20 and CD 10. These findings were consistent with large B-cell lymphoma. Central nervous system radiation with a dose of 56 Gy was given with clinical and radiological improvement. The patient died due to multiorgan failure. Finally, the immunocompromised patients should be closely followed for the development of lymphoproliferative disorder.