Summary.A 32-year-old woman with relapsed Philadelphia chromosome-positive acute lymphoblastic leukaemia was treated with imatinib mesylate (formerly STI571), a selective inhibitor of BCR/ABL tyrosine kinase. Although the initial marrow response was good and stably maintained, she subsequently relapsed with extensive infiltration of leukaemic cells into the central nervous system (CNS). After controlling her CNS disease with additional intrathecal chemotherapy, we measured the concentration of imatinib in cerebrospinal fluid (CSF) and blood simultaneously. The concentration of imatinib in CSF was about 92-fold lower than that in blood. These results suggest that imatinib poorly penetrates the blood-brain barrier and has limited activity against CNS leukaemia.

Apoptosis mediated by verotoxins (VTs) has been identified in a renal carcinoma cell line, ACHN cells, which are an in vitro model of renal tubular epithelial cells. ACHN cells express the renal tubular marker CD24 as well as globotriaosyl ceramide/CD77, the receptor for VTs. VT binding to the ACHN cell surface was confirmed by positive staining with antibodies to the VTs. Treatment of ACHN cells with VTs induced prompt growth inhibition and cell death, and fragmentation of the genomic DNA in cells, typical of apoptosis, was observed. The expression of apoptotic antigen 7A6 detected by APO2.7 antibody in ACHN cells further supports the occurrence of apoptosis as a result of VT treatment. Cycloheximide enhanced VT-mediated apoptosis of ACHN cells, suggesting a strong correlation between the inhibition of protein synthesis and VT-mediated apoptosis. Moreover, tumor necrosis factor-alpha had a synergistic effect on VT-mediated apoptosis in ACHN cells. Considering the above evidence together with the clinical evidence showing the presence of apoptosis in the renal epithelium of a HUS patient, our results suggest a VT-induced apoptotic mechanism in normal renal tubular epithelium that may contribute to the pathogenesis of hemolytic uremic syndrome.

The cytotoxicity of Shiga toxin (Stx) 1 and Stx2 produced by Escherichia coli to human renal cortical epithelial cells (HRCEC) in primary culture was investigated. HRCEC express CD24, the marker of renal distal tubules, as well as globotriaosyl ceramide/CD77, the receptor for Stxs. Binding of Stxs to HRCEC was confirmed by positive staining with specific antibodies to Stxs. Treatment of HRCEC with Stxs induced rapid cell death, which was reversed in the presence of neutralizing antibody specific for Stx. DNA fragmentation was found to be accompanied by Stx-mediated cell death in HRCEC, indicating that apoptosis was part of the process. These data and previous reports indicate that a variety of renal cell types, including tubular epithelial cells as well as glomerular capillary endothelial cells, may be targets for Stx-mediated apoptosis, which could contribute to the pathogenesis of hemolytic-uremic syndrome caused by Stx-producing E. coli infection. In connection with the above reports, we previously demonstrated that Stxs are cytotoxic to the renal carcinoma line as well as the pathogenesis of HUS are still unclear. However, on the basis of histopathologic findings [3] and in vitro experi-ACHN, an in vitro model of human renal tubular epithelial cells, which is 10 6 -to 10 7 -fold more sensitive to Stxs than are ments [4 -7], endothelial damage in the glomeruli and arterioles of the kidney induced by Stx is believed to play a crucial HUVEC [17]. More interestingly, we have recently shown that apoptosis is involved in Stx-mediated cytotoxicity against role in the pathogenesis of Stx-mediated HUS [4, 8]. A few observations on the correlation between apoptosis of glomeru-ACHN cells [18]. To address whether these observations in ACHN represent lar endothelial cells and sporadic (non -Stx-mediated) HUS or the nature of normal tubular epithelial cells in the kidney, we examined the effect of Stxs on normal human renal cortical epithelial cells (HRCEC) by using a primary culture system. in primary culture, derived from a 24-year-old volunteer, were Recent worrisome increases in the incidences

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Summary:We have prospectively evaluated the efficacy of realtime PCR-guided preemptive therapy for CMV diseases in allogeneic hematopoietic stem cell transplant recipients with grades II-IV acute GVHD. The dose of ganciclovir was adjusted according to the viral load determined by real-time polymerase chain reaction (PCR). On detecting CMV reactivation in the plasma, ganciclovir was initiated at a dose of 5 mg/kg body weight once daily, and the dose was increased to twice daily if viral load continued to increase after initiating ganciclovir. In 39 evaluable patients, CMV reactivation assessed by real-time PCR became positive in 30 (77%). One developed CMV gastroenteritis before PCR became positive. Thus the remaining 29 patients were treated preemptively with ganciclovir. The dose of ganciclovir was increased in 12 patients (41%) of preemptively treated patients for increasing viral load. CMV diseases were diagnosed in two patients (one gastroenteritis and one retinitis), and late CMV disease was diagnosed in one patient (gastritis). The treatment was generally well-tolerated, but three patients (10%) developed neutropenia (neutrophil count less than 1.0 × 10 9 /l). In conclusion, real-time PCR-guided preemptive therapy with decreased dose of ganciclovir is feasible and does not increase the frequency of CMV diseases if the dose is adjusted according to the viral load.

Malignant lymphoma is the most common form of hematologic cancer, yet because of advanced methods of assessment, the traditional histology-based classification of lymphoma is insufficient for understanding lymphoma imaging. Still, radiologists should be familiar with the imaging findings in lymphoma. Integrated positron emission tomography (PET)-computed tomography (CT) allows improved diagnostic accuracy, and uptake of 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) can help predict response during treatment. The sensitivity and specificity of FDG PET are superior to those of gallium 67 scintigraphy in all but indolent lymphoma. Both magnetic resonance (MR) imaging and CT allow excellent assessment of bone texture, but FDG PET is superior in demonstrating bone marrow metabolic activity. Thus, FDG PET is important in both the primary diagnosis and the evaluation of therapy in lymphoma. It may be difficult to determine whether residual abnormalities seen after the completion of chemotherapy-radiation therapy represent residual tumor or fibrotic tissue, but PET/CT may allow more accurate diagnosis than MR imaging or CT, thereby helping identify patients who require more intensive treatment. Some diagnostic pitfalls are encountered at FDG PET. However, anatomic CT helps localize and define disease and avoid these potential pitfalls.

Shiga toxin 1 (Stx1) produced by Escherichia coli has been reported to induce apoptosis in many different cell types, including Burkitt's lymphoma (BL) cells. Since it has been established that the caspases play essential roles as the effector molecules in the apoptotic process in most cases, we examined the kinetics of caspase activation during the process of Stx1-mediated apoptosis of BL cells. Using Ramos BL cells that are highly sensitive to Stx1-mediated cytotoxicity, we observed that multiple caspases, including caspase-3, -7, and -8 were promptly activated following Stx1 treatment, as indicated by both the procaspase cleavages and enhancement of cleavage of the tetrapeptide substrates of the caspases. In addition, the inhibition assay revealed that caspase-8 is located upstream of both caspase-3 and -7, suggesting that Stx1-mediated apoptosis utilizes a similar caspase cascade to that involved in Fas-mediated apoptosis. Neither anti-Fas mAb nor TNF-alpha, however, affected the Stx1-mediated apoptosis of Ramos cells. Although the precise mechanism of Stx1-mediated activation of caspase-8 is still unclear, we have demonstrated that crosslinkage of CD77, a functional receptor for Stx1, with specific antibody is sufficient to induce activation of caspase-8. Our findings should provide new insight into the understanding of the molecular basis of Stx1-mediated cell injury.

Recent reports that bone marrow angiogenesis is increased in multiple myeloma prompted us to examine plasma concentrations of angiogenic growth factors and to elucidate their clinical and biological significance. In 45 cases including 36 cases of multiple myeloma and 9 cases of monoclonal gammopathies of undetermined significance (MGUS), plasma concentrations of basic fibroblast growth factor (FGF-2) and vascular endothelial growth factor (VEGF) were evaluated. FGF-2 was significantly elevated in 25 out of 45 (56%) of the patients with multiple myeloma compared with control subjects (median 9.01 pg/ml vs. 1.58 pg/ml, P < < < <0.0001). The 25 cases were all active multiple myeloma, and none of the non-active myeloma and MGUS patients showed a high FGF-2 level. VEGF level was also elevated in 26 out of 45 patients (58%) compared with control subjects (median 42.0 pg/ml vs. 15.8 pg/ml, P < < < <0.0001 for VEGF). VEGF concentration was high in 20 active myelomas, but also in one non-active myeloma and five MGUS. Elevation of FGF-2 level was associated with β β β β2-microglobulin level, anemia and bone marrow plasma cell percentage, which represent disease activity. Interestingly, none of five Bence-Jones type myelomas, including four clinically active cases, revealed a high plasma FGF-2 level, while all of them showed a high VEGF level. In all five responders, the plasma FGF-2 levels were significantly decreased after chemotherapy. FGF-2 was immunohistochemically detected in the bone marrow myeloma cells of the patients with high plasma FGF-2 level. We conclude that plasma concentration of FGF-2 can be a useful indicator of disease activity.