Mutations in a member of the ADAMTS gene family cause thrombotic thrombocytopenic purpura.

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening systemic illness of abrupt onset and unknown cause. Proteolysis of the blood-clotting protein von Willebrand factor (VWF) observed in normal plasma is decreased in TTP patients. However, the identity of the responsible protease and its role in the pathophysiology of TTP remain unknown. We performed genome-wide linkage analysis in four pedigrees of humans with congenital TTP and mapped the responsible genetic locus to chromosome 9q34. A predicted gene in the identified interval corresponds to a segment of a much larger transcript, identifying a new member of the ADAMTS family of zinc metalloproteinase genes (ADAMTS13). Analysis of patients' genomic DNA identified 12 mutations in the ADAMTS13 gene, accounting for 14 of the 15 disease alleles studied. We show that deficiency of ADAMTS13 is the molecular mechanism responsible for TTP, and suggest that physiologic proteolysis of VWF and/or other ADAMTS13 substrates is required for normal vascular homeostasis.

Metastasis stage, adjuvant treatment, and residual tumor are prognostic factors for medulloblastoma in children: conclusions from the Children's Cancer Group 921 randomized phase III study.

PURPOSE: From 1986 to 1992, "eight-drugs-in-one-day" (8-in-1) chemotherapy both before and after radiation therapy (XRT) (54 Gy tumor/36 Gy neuraxis) was compared with vincristine, lomustine (CCNU), and prednisone (VCP) after XRT in children with untreated, high-stage medulloblastoma (MB). PATIENTS AND METHODS: Two hundred three eligible patients with an institutional diagnosis of MB were stratified by local invasion and metastatic stage (Chang T/M) and randomized to therapy. Median time at risk from study entry was 7.0 years. RESULTS: Survival and progression-free survival (PFS) +/- SE at 7 years were 55%+/-5% and 54%+/-5%, respectively. VCP was superior to 8-in-1 chemotherapy, with 5-year PFS rates of 63%+/-5% versus 45%+/-5%, respectively (P = .006). Upon central neuropathology review, 188 patients were confirmed as having MB and were the subjects for analyses of prognostic factors. Children aged 1.5 to younger than 3 years had inferior 5-year estimates of PFS, compared with children 3 years old or older (P = .0014; 32%+/-10% v 58%+/-4%, respectively). For MB patients 3 years of age or older, the prognostic effect of tumor spread (MO v M1 v M2+) on PFS was powerful (P = .0006); 5-year PFS rates were 70%+/-5%, 57%+/-10%, and 40%+/-8%, respectively. PFS distributions at 5 years for patients with M0 tumors with less than 1.5 cm2 of residual tumor, versus > or = 1.5 cm2 of residual tumor by scan, were significantly different (P = .023; 78%+/-6% v 54%+/-11%, respectively). CONCLUSION: VCP plus XRT is a superior adjuvant combination compared with 8-in-1 chemotherapy plus XRT. For patients with M0 tumors, residual tumor bulk (not extent of resection) is a predictor for PFS. Patients with M0 tumors, > or = 3 years with < or = 1.5 cm2 residual tumor, had a 78%+/-6% 5-year PFS rate. Children younger than 3 years old who received a reduced XRT dosage had the lowest survival rate.

Pediatric bone marrow cellularity: are we expecting too much?

PURPOSE: Accurate assessment of marrow cellularity is necessary for establishing diagnoses and monitoring the effects of treatment in a large number of malignant and nonmalignant pediatric illnesses, and for evaluating sibling donors for transplantation. However, normal values for age-related bone marrow cellularity in pediatric patients have not been well established. This study was designed to better define pediatric normal values for bone marrow cellularity. PATIENTS AND METHODS: A retrospective review of 448 bone marrow core biopsy or clot specimens, including 45 samples from healthy donors, were taken from the posterior iliac crest of patients aged from younger than 1 to 18 years (55% male). All samples were collected and fixed in a standardized fashion. Patients with hematopoietic malignancies and other systemic conditions known to impact marrow cellularity were excluded. RESULTS: The mean cellularity of the entire sample was 65.4%. Cellularity was similar in boys and girls, but varied (p < 0.001) with age. Cellularity was highest in patients younger than 2 years (79.8%), and declined in patients 2 to 4 years old (68.6%) and 5 to 9 years old (59.1%). Cellularity remained stable in older patients (60.1% and 61.1%, respectively, in patients 10 to 14 and 15 to 18 years of age). Adjusting for age and gender, mean cellularity was similar in patients with an underlying nonhematologic malignancy compared to health donors but was roughly 6% higher in patients with hematopoietic disorders. CONCLUSIONS: This study demonstrates that average cellularity during the first two decades of life, using current techniques of marrow collection and standardized analysis, is lower than previously estimated. In addition, cellularity declined with age until the age of 5 years, but was similar thereafter. After adjusting for age, differences according to diagnosis were relatively small.

Ketamine-midazolam versus meperidine-midazolam for painful procedures in pediatric oncology patients.

PURPOSE: To compare the efficacy, characteristics of onset/recovery, and safety of ketamine/atropine/midazolam with meperidine/midazolam used as premedication for painful procedures in children with cancer. METHODS: A randomized, double-blind crossover trial for two successive painful procedures (bone marrow aspiration or biopsy, lumbar puncture, or combined procedures) was performed at a referral-based pediatric hematology-oncology clinic and associated inpatient service of a university teaching hospital. Twenty-two children, aged 24 to 178 months, were enrolled and 18 (81.8%) completed the double-blind, crossover trial. Each child received intravenous premedication with either meperidine 2 mg/kg and midazolam 0.1 mg/kg (MM) or atropine 0.01 mg/kg, midazolam 0.05 mg/kg, and ketamine 1.5 mg/kg (KM) on one occasion followed by the alternative regimen on a second occasion. The initial premedication regimen was chosen by random assignment. RESULTS: Efficacy was assessed by a trained observer using the Observational Scale of Behavioral Distress-Revised (OSBD-R). Operator, nurse, parent, and patient opinions of efficacy were recorded on a visual analog scale (VAS). Side effects were monitored by pulse oximetry, nasal end-tidal capnography, and serial blood pressure measurements. Use of KM resulted in significantly less procedural distress than MM (1.37 +/- 2.20 v 7.04 +/- 8.06 OSBD-R units; P < .05). Both operators and nurses rated KM more effective than MM. KM use was associated with earlier readiness for the procedure (19.2 v 24.0 minutes) and more rapid recovery (39.3 v 74.6 minutes for removal of monitoring devices and 58.5 v 87.1 minutes for discharge). Procedures undertaken after ketamine sedation were associated with fewer side effects than observed with MM sedation (hypoxia, 17.7% v 82.4%; hypotension, 16.6% v 55.6%; reduced respiratory rate, 0% v 38.9%). The incidence of emergence reactions or behavioral abnormalities within 24 hours postprocedure was similar in both treatment groups. At 7 days postprocedure, no child had persistent behavioral abnormalities and all children had amnesia for the procedure. Parents and children expressed a preference for KM over MM in 12 of 18 cases (P < .05). CONCLUSION: A premedication regimen of KM produced superior sedation with a faster onset and recovery and fewer side effects than a MM combination.

Effects of a ketogenic diet on tumor metabolism and nutritional status in pediatric oncology patients: two case reports.

OBJECTIVE: Establish dietary-induced ketosis in pediatric oncology patients to determine if a ketogenic state would decrease glucose availability to certain tumors, thereby potentially impairing tumor metabolism without adversely affecting the patient's overall nutritional status. DESIGN: Case report. SETTING: University Hospitals of Cleveland. SUBJECTS: Two female pediatric patients with advanced stage malignant Astrocytoma tumors. INTERVENTIONS: Patients were followed as outpatients for 8 weeks. Ketosis was maintained by consuming a 60% medium chain triglyceride oil-based diet. MAIN OUTCOME MEASURES: Tumor glucose metabolism was assessed by Positron Emission Tomography (PET), comparing [Fluorine-18] 2-deoxy-2-fluoro-D-glucose (FDG) uptake at the tumor site before and following the trial period. RESULTS: Within 7 days of initiating the ketogenic diet, blood glucose levels declined to low-normal levels and blood ketones were elevated twenty to thirty fold. Results of PET scans indicated a 21.8% average decrease in glucose uptake at the tumor site in both subjects. One patient exhibited significant clinical improvements in mood and new skill development during the study. She continued the ketogenic diet for an additional twelve months, remaining free of disease progression. CONCLUSION: While this diet does not replace conventional antineoplastic treatments, these preliminary results suggest a potential for clinical application which merits further research.

Trilateral retinoblastoma: two variations.

Two cases of trilateral retinoblastoma (a syndrome of midline, undifferentiated, intracranial tumor in a child with hereditary, bilateral ocular retinoblastoma) are described, one with a unique location of the intracranial tumor, and the other with an unusual temporal course of disease.

Myelodysplastic syndrome and acute myeloid leukemia after treatment for solid tumors of childhood.

Three cases of secondary (therapy-related) hematologic malignant conditions were identified among 95 children as old as 18 years of age; the cases were diagnosed between 1984 and 1990 and consisted of acute lymphoblastic leukemia, acute myeloid leukemia (AML), and myelodysplastic syndrome (MDSs). They constituted 10% of all new cases of AML and MDS seen at the University Hospitals of Cleveland during this time and were not related to congenital factors. The primary malignant conditions were malignant thoracopulmonary tumor (Askin tumor), neuroblastoma, and Burkitt's lymphoma. The secondary hematologic disorders all showed a prominent monocytic component: acute monocytic leukemia, MDSs evolving to acute myelomonocytic leukemia, and chronic myelomonocytic leukemia. The mean interval between treatment for the primary malignant condition and the onset of secondary disease was 36 months. All had received cyclophosphamide and an epipodophyllotoxin for the primary tumor; two were treated with radiation therapy. Cytogenetic abnormalities included del(5), del(13), t(1;6), and t(9;11)(p22[symbol:see text]3). The survival time after the onset of secondary disease was short.

Inhibition of the activation of hageman factor (factor XII) by eosinophils and eosinophilic constituents.

Several syndromes characterized by striking eosinophilia may be complicated by thrombosis. The experiments described indicate that, paradoxically, eosinophils and certain of their constituents inhibit the activation of Hageman factor (HF, factor XII). In earlier studies, suspensions of mixed types of granulocytes, other nucleated peripheral blood cells, and platelets inhibited activation of Hageman factor by ellagic acid, glass, and sulfatides. After these cells were sedimented by centrifugation, the supernatant fluids were also inhibitory. No attempt had been made earlier to distinguish among different granulocytic species. In the present study, suspensions of eosinophils and the supernatant fluid after eosinophils had been separated by centrifugation inhibited activation of Hageman factor by ellagic acid. The protein concentration of that amount of supernatant fluid that inhibited activation by about half was 16 micrograms/ml, approximately the same as had been described for suspensions of peripheral blood mononuclear cells. Activation of Hageman factor by ellagic acid was also inhibited by certain constituents of eosinophils, including eosinophil peroxidase, eosinophil major basic protein and eosinophil cationic protein. Inhibition was not specific for ellagic acid-induced activation of Hageman factor, as inhibition was also observed with sulfatide-induced activation. Inhibition was presumably related to neutralization of the negative charge of activators of Hageman factor. Thus, bismuth subgallate, a particulate activator of Hageman factor, was no longer effective after it had been exposed to eosinophil cationic protein. The observations reported here raise the question of whether in vivo eosinophils modulate certain of the defense reactions ascribed to Hageman factor.

Pneumatosis cystoides intestinalis in children beyond the first year of life: manifestations and management.

Beyond infancy, pneumatosis cystoides intestinalis (PCI) is rare. Data concerning pathogenesis and treatment are limited. Our experience with 12 children was examined to define predisposing factors, presentation, treatment, and outcome. Nine children were immunosuppressed, thus identifying an important etiologic subgroup. Presentation was variable but included abdominal pain, distention, diarrhea and hematochezia. Clostridium difficile was found in 3 patients and cytomegalovirus in 1. Radiographs showed free air in 3. Nine were treated with antibiotics and bowel rest, 1 with bowel rest alone, 1 with oral metronidazole, and 1 with observation. PCI resolved in 7 of 9 treated with antibiotics, although 1 child with leukemia had severe hematochezia secondary to colonic ulceration and required hemicolectomy. No other patient required laparotomy. The free air resolved in 2 of 3. There were 2 deaths, both from sepsis. One had free air on admission but no perforation was found at autopsy. Treatment recommendations remain unclear; however, C difficile and cytomegalovirus are important pathogens that should be identified and treated promptly. In symptomatic patients, bowel rest and antibiotics seem beneficial. Operative intervention should be reserved for patients with peritoneal signs, progressive deterioration, obstruction, or persistent, severe bleeding. Free air alone is not an indication for operative management in children with PCI.

Extracellular adenosine triphosphate activates calcium mobilization in human phagocytic leukocytes and neutrophil/monocyte progenitor cells.

We have examined the ability of extracellular ATP to elicit intracellular Ca2+ mobilization in a broad range of human leukocytes at particular stages of hematopoietic differentiation. The average cytosolic [Ca2+] in various leukocyte populations was measured in Fura 2-loaded cell suspensions while the cytosolic [Ca2+] in individual, Indo 1-loaded leukocytes was assayed by flow cytometric methods. Utilizing normal blood- and marrow-derived cells, human leukemic cell lines, and mononuclear cell fractions derived from the blood of patients with various leukemias, we have found that ATP-induced Ca2+ mobilization appears restricted to leukocytes of neutrophil/monocyte ontogeny. Significant ATP-induced increases in cytosolic [Ca2+] were observed in neutrophils, monocytes, and myeloid progenitor cells as immature as myeloblasts, but not in lymphocytes. Extensive characterization of the ATP-induced changes in [Ca2+] observed in the HL-60 promyelocytic cell line have indicated these Ca2+-mobilizing effects of ATP can be correlated with an activation of inositol phospholipid breakdown via the occupation of P2-purinergic receptors Significantly, of the various agonists (FMLP, platelet-activating factor, LTB4, and ATP) which elicit equivalent and maximal Ca2+ mobilization in mature neutrophils and monocytes, ATP was the most efficacious stimulant of Ca2+ mobilization in immature neutrophil/monocyte precursors. Thus, expression of putative P2-purinergic receptors for ATP appears to precede expression of other receptor types known to activate the inositol phospholipid signaling cascades in terminally differentiated phagocytes.

Neonatal neutropenia. Clinical manifestations, cause, and outcome.

Neutropenia, defined as an absolute neutrophil count that falls below 2.0 x 10(9)/L, is being identified more frequently in the newborn intensive care unit and significantly influences clinical decisions regarding therapy. We prospectively identified 119 episodes of neutropenia in 87 infants (6% of admissions). Less than half of the episodes could be attributed to infections. The majority of noninfectious neutropenia episodes were related to specific perinatal events or were of unknown cause. Infants weighing less than 2500 g were more likely to have neutropenia than term infants (13% vs 3%, respectively) and less likely to have neutropenia related to bacterial infections. Short-term survival (89% vs 95%) and long-term survival (74% vs 77%) were not different in infants with infectious diseases compared with those with noninfectious diseases. Mortality was highly correlated with the need for assisted ventilation (20%) or with an absolute neutrophil count of 0.5 x 10(9)/L (24%). We conclude that the cause of neutropenia and the clinical condition must be carefully evaluated before instituting aggressive therapy for infection.

Pathologic states associated with activation of eosinophils and with eosinophilia.

Eosinophils are involved in cytotoxicity against helminths and tumor cells and effect both tissue damage and tissue protection in hypersensitivity reactions. Their migratory patterns and oxidative mechanisms are most similar to those of neutrophils, but their tissue longevity and functional variation are more similar to those of monocytes and macrophages. Their enzyme components and behaviors are only now beginning to be defined, and their biologic functions in pathologic states remain a topic of considerable discussion.

Chronic granulomatous disease due to a defect in the cytosolic factor required for nicotinamide adenine dinucleotide phosphate oxidase activation.

The superoxide-generating enzyme of human neutrophils, NADPH oxidase, is present in a dormant state in unstimulated neutrophils. It can be converted to an active form in a cell-free system if both the plasma membrane and cytosol fractions are incubated together in the presence of arachidonic acid. This system was used to determine the nature of the biochemical defect in seven patients with the autosomal recessive, cytochrome b-positive form of chronic granulomatous disease (CGD). A severe deficiency in the cytosol factor was identified in each patient. The defective activity was not caused by the presence of an inhibitor, nor could it be restored to normal by combining cytosol fractions from different patients. In contrast, the membrane fractions from all seven patients contained normal levels of NADPH oxidase when activated in the presence of control cytosol. Of family members tested (obligate heterozygotes for this disorder), seven of eight had intermediate levels of cytosol factor activity. The respiratory burst defect in this form of CGD is caused by an abnormality in the cytosolic factor required for NADPH oxidase activation.