Stenosis or hyperperfusion in sickle cell disease--ultrasound assessment of cerebral blood flow volume.

Increased blood flow velocity (BFV) in basal cerebral arteries measured by transcranial color-coded sonography (TCCS) is a stroke risk factor in sickle cell disease (SCD). Raised BFV may be caused by vessel narrowing or by hyperperfusion. In 44 SCD patients and 14 controls, intracranial arterial BFVs and global cerebral blood flow (CBF) were analyzed by TCCS and extracranial duplex ultrasound, respectively. Magnetic resonance imaging and magnetic resonance angiography were performed in all patients with pathologic intracranial BFV rise. Intracranial BFVs and CBF in SCD were significantly higher than in controls. CBF in SCD correlated with BFV in all intracranial arteries and correlated inversely with age and hemoglobin values. Magnetic resonance angiography failed to demonstrate any stenosis in our SCD patients, thus raised intracranial BFVs must be interpreted as an anemia-dependent cerebral hyperperfusion. These findings suggest that the pathomechanism of stenosis-derived arterio-arterial embolism might be less relevant in SCD-related ischemic stroke, and other factors like small vessel disease or sickle cell-induced microvascular blood clotting have to be considered.

Salvage therapy for relapsed posttransplant lymphoproliferative disorders (PTLD) with a second progression of PTLD after Upfront chemotherapy: the role of single-agent rituximab.

Currently no standard treatment exists for patients with posttransplant lymphoproliferative disorders relapsed or refractory to chemotherapy after failure of reduction in immunosuppression. We have analyzed the effects of single-agent rituximab treatment in eight patients (seven adult, one pediatric) in this setting. Three patients had been salvaged with rituximab several times. In the seven adults, rituximab salvage therapy achieved complete remission (CR) in three patients (43%) and partial remission in one (14%). In the pediatric patient, a PR was obtained that could be reinduced on relapse with repeated administrations of rituximab. Patients achieving CR either remained in CR or were successfully salvaged again with single-agent rituximab. At a median follow-up of 69 months, median progression-free survival was 9 months and no relevant therapy-associated toxicity was observed. Single-agent rituximab salvage therapy is an effective treatment option in this setting of intensively pretreated patients, with virtually no therapy-associated toxicity.

Interaction of bone marrow stromal cells with lymphoblasts and effects of predinsolone on cytokine expression.

Cytokines play a key role in the differentiation, growth and survival of hematopoietic cells in the bone marrow (BM) stroma microenvironment. The mechanisms by which stromal derangements may contribute to the evolution of hematopoietic neoplasias are largely unknown. Here, we characterized BM stromal cells isolated from children with acute lymphoblastic leukemia and determined the effect of the interaction between stromal cells and lymphoblasts on cytokine expression as well as the effect of prednisolone using mono- and co-culture models. The analyses demonstrate that (1) stromal cells and lymphoblasts display different patterns of cytokine gene expression individually. (2) Stromal cells influence gene expression of cytokines in lymphoblasts and vice versa. (3) Glucocorticoid substitution inhibit cytokine gene expression in stromal cells. These findings indicate that stromal cells are important components involved in malignant hematopoiesis and also in response to therapy.

Transcranial Doppler ultrasonography in neurologically asymptomatic children and young adults with sickle cell disease.

The purpose of the study was to evaluate transcranial Doppler ultrasonography for identifying cerebrovascular disease in neurologically asymptomatic children and young adults with sickle cell disease. A total of 47 consecutive patients with sickle cell disease (28 females, 19 males; age range 8 months to 29 years, mean age 9 years 6 months) were evaluated by transcranial color and duplex Doppler ultrasonography via transtemporal and occipital (2-MHz probe) as well as by transocular (5-MHz probe) approach. Eleven vessels (middle, posterior, anterior cerebral artery, vertebral artery, ophthalmic artery on each side and basilar artery) were analyzed in each patient. Following nine transcranial Doppler findings predictive for cerebrovascular disease, patients with one or more of those abnormal sonographic findings underwent MR imaging and MR angiography. In 8 patients with abnormal transcranial Doppler the MR angiography was normal. Thirty-one patients demonstrated normal results. In 15 of 16 patients with one or more abnormal Doppler findings (34% of all studied patients) MR imaging and MR angiography were performed. The MR angiography disclosed cerebrovascular stenosis in 7 patients (15% of all patients, 44% of those with pathological transcranial Doppler findings). In one of those patients MR imaging revealed silent peripheral ischemic infarction as well. Our findings indicate the usefulness of transcranial Doppler ultrasonography to reveal occult cerebrovascular lesions in neurologically asymptomatic patients with sickle cell disease. It should regularly be performed in all sickle cell patients in order to detect patients at risk for later stroke. Patients with homozygous disease and a high frequency of preceding sickle cell crises should be followed most closely.

Unusual mesoblastic nephroma in a young child.

We report a 1-year 11-month-old girl demonstrating a large renal mass with a unique presentation on imaging (US, CT and plain radiography), pathology and histology. The imaging features did not correspond with a Wilms' tumour, the most commonly found renal tumour in the child of this age. The US and CT findings resembled a benign lesion with an unusually high fat content. Histological evaluation demonstrated a congenital mesoblastic nephroma, a tumour entity typical for the neonatal period or early infancy, with an additional unusual, predominantly lipomatous differentiation.