Pathophysiology of hemolysis in infections with Hemophilus influenzae type b.

The capsular polysaccharide of Hemophilus influenzae type b, polyribosyl ribitol phosphate (PRP), is released from growing organisms during human infection and can be found in body fluids. It binds to untreated erythrocytes. Many patients with invasive infections with this organism develop significant hemolysis, but the mechanism has been unclear. We have found that PRP binds to human erythrocytes in vivo. PRP-coated erythrocytes have a shortened circulation time in mice, but do not lyse spontaneously or fix complement. PRP-coated erythrocytes exposed to antiserum to H. influenzae type b are undamaged in the absence of complement, but are rapidly and effectively lysed in the presence of an intact complement system both in vitro and in vivo in mice. PRP-coated red cells are taken up by liver and spleen. Antiserum to PRP increases hepatic uptake of PRP-coated red cells more than splenic, and appears to induce intravascular, complement-mediated hemolysis, as well as extravascular hemolysis. Patients with invasive infection develop hemolysis when circulating PRP and antibody to PRP are present simultaneously. PRP can sometimes be detected on patient erythrocytes when free PRP is present in serum, but this is an inconsistent finding. The hemolytic anemia that occurs during human infection with H. influenzae type b may be due to absorption of PRP to red cells and immune destruction of sensitized erythrocytes. The process requires an intact complement system; both complement-mediated cell lysis and extravascular hemolysis contribute to red cell destruction.

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.

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.

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.

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.

Optic atrophy induced by vincristine.

Bilateral optic atrophy developed in a 15-year-old patient receiving concomitant neuraxis radiation therapy and weekly vincristine sulfate for medulloblastoma. Other neurologic manifestations that have been associated with vincristine therapy, including inappropriate secretion of antidiuretic hormone, hypertension, confusion, and a severe peripheral neuropathy, were also observed. Neither increased intracranial pressure nor active tumor was identified. Recovery of visual function followed discontinuation of vincristine. Other neurotoxicities also reversed with drug withdrawal. Visual loss occurring in a patient receiving vincristine should alert the physician to the possibility that the process is drug related. This complication may be more likely in patients receiving concomitant or previous cranial radiation therapy. Other central neurotoxicities of vincristine may also be accentuated by neuraxis radiation. It is recommended that vincristine be discontinued in this situation if an aggressive search for a structural anatomic lesion in the optic mechanism is unrevealing, as the prognosis for recovery of visual function appears excellent.

Buffy coat transfusions in neutropenic neonates with presumed sepsis: a prospective, randomized trial.

Neonatal sepsis, accompanied by neutropenia, is associated with a high mortality. To determine whether granulocyte transfusions improve the survival of critically ill neutropenic infants, we prospectively randomized 25 infants to transfusion and nontransfusion groups, matching for birth weight (less than or equal to 1,500 g or greater than 1,500 g). Infants with necrotizing enterocolitis were randomized separately. Neutropenia was established by two successive absolute neutrophil counts less than or equal to 1,500 cells prior to randomization. The transfusion (n = 12) and nontransfusion (n = 13) groups did not differ with respect to clinical or hematologic characteristics. In 23 of 25, bone marrow aspirations were performed to determine the percentage of neutrophil storage pool. Granulocyte transfusions of buffy coats from single units of whole blood (0.1 to 0.9 X 10(9) polymorphonuclear leukocytes per kilogram) were given daily until the absolute neutrophil count increased to more than 1,500/microL. Only five infants, mostly those with necrotizing enterocolitis, required more than one transfusion. A circulating immature to total neutrophil ratio (I:T) greater than or equal to 0.80 was not predictive of an infant with a neutrophil storage pool less than or equal to 7%, and neither an I:T less than 0.80 nor a neutrophil storage pool greater than 7% were predictive of survival. Granulocyte transfusions did not improve survival when either comparing the whole group, those 17 infants with cultures positive for bacteria or viruses, the 19 infants with a circulating I:T greater than or equal to 0.80, or the nine infants with a neutrophil storage pool less than or equal to 7%.(ABSTRACT TRUNCATED AT 250 WORDS)

Multiple microaerophilic streptococcal lung abscesses after orthodontic treatment.

An immunocompetent 12-year-old boy developed multiple microaerophilic streptococcal lung abscesses after application of orthodontic bands ("braces"). The dental work was done in the supine position. The data suggest that the patient aspirated the organisms and, possibly, flecks of dental cement, during orthodontic treatment. "Rubber dams" should be used to help prevent aspiration in children who receive dental work in the supine position. When a rubber dam cannot be used, as with orthodontic treatment, physicians should advise patients who are at risk for developing pulmonary infection (eg, patients with neuromuscular diseases which compromise cough and/or gag, cystic fibrosis, sickle cell anemia, primary immunodeficiency, etc) to have this dental work, including orthodontic treatment, performed in the erect position.

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.

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.

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.

Quadriplegia secondary to hematoma after lateral C-1, C-2 puncture in a leukemic child.

Epidural, subdural, and intramedullary hemorrhage developed after lateral cervical (C-1, C-2) puncture in a thrombocytopenic patient with meningeal leukemia and increased intracranial pressure. Aggressive platelet support before the procedure did not prevent the hemorrhagic complication. Complete recovery from total motor paralysis with respiratory arrest followed immediate surgical decompression and continuing platelet support. The potential dangers of otherwise minor procedures in compromised patients are reiterated. Neurological recovery as seen here argues for immediate surgical intervention with the development of such potentially life-threatening events.

Disseminated intravascular coagulation as a complication of ventricular catheter placement. Case report.

A child who developed generalized bleeding immediately after placement of a ventriculoperitoneal shunt was found to have evidence of disseminated intravascular coagulation (DIC). Infusion of fresh frozen plasma was followed promptly by improvement in laboratory values and cessation of bleeding. Complications of the acute bleeding episode included intraventricular hemorrhage, loss of 50% of the red cell volume into subcutaneous tissues, and transient peritoneal irritation. Defibrination syndrome (that is, DIC) due to release of tissue thromboplastin is a recognized complication of trauma, particularly with brain injury. Defibrination can be induced in experimental systems with administration of very small amounts of thromboplastin, which is present in high concentration in brain tissue. This has not been described previously with minor neurosurgical procedures. The diagnosis of DIC should be considered if excessive bleeding occurs after any brain insult, since early recognition and restoration of normal hemostasis by replacement of clotting factors should prevent major complications due to ongoing hemorrhage.

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.