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Biomedical subjects

D H Mahoney

Publications and source records attributed to D H Mahoney.

At least 55 records · Page 3Linked to original sources
PubMed1992

Chronic relapsing thrombotic thrombocytopenic purpura in infants with large von Willebrand factor multimers during remission.

We studied two children with recurrent schistocytic hemolytic anemia and thrombocytopenia beginning in the neonatal period. One patient had a stroke during one of the episodes of thrombotic thrombocytopenic purpura. The presence of unusually large von Willebrand factor multimers was demonstrated in both children during clinical and hematologic remissions. Treatment with corticosteroids and intravenous injections of immune globulin was unsuccessful in the one patient who received it. Immediate improvement occurred in both patients after the infusion of fresh-frozen plasma. Symptoms of thrombocytopenia continue to recur at regular intervals in the absence of periodic fresh-frozen plasma infusions. One of these children apparently has chronic relapsing thrombotic thrombocytopenic purpura; the second has a chronic relapsing disorder similar to thrombotic thrombocytopenic purpura.

Blood Component Transfusion↗
PubMed1992

Immunogenicity of Haemophilus influenzae type b polysaccharide-tetanus protein conjugate vaccine in children with sickle hemoglobinopathy or malignancies, and after systemic Haemophilus influenzae type b infection.

To determine the immunogenicity of Haemophilus influenzae type b polysaccharide-tetanus protein conjugate vaccine in specific populations at risk, we administered vaccine to children with sickle cell anemia (n = 19; mean age, 18.3 months, malignancies (n = 18; mean age, 43.1 months), or a recent history of systemic H. influenzae type b infection (n = 17; mean age, 11.9 months). After one dose of polyribosylribitol phosphate-tetanus toxoid conjugate vaccine the geometric mean titers for polyribosylribitol phosphate antibody were 4.8 micrograms/ml (14/19 greater than 1 microgram/ml), 1.4 micrograms/ml (9/18 greater than 1 microgram/ml), and 5.6 micrograms/ml (15/17 greater than 1 microgram/ml) in these three groups, respectively. Children with sickle cell anemia or a recent history of systemic H. influenzae type b infection had polyribosylribitol phosphate antibody levels comparable to those of normal children of similar age after one or two doses of polyribosylribitol phosphate-tetanus toxoid conjugate vaccine. We conclude that this vaccine is immunogenic in children with underlying conditions associated with an increased risk of H. influenzae type b infection.

Anemia, Sickle Cell↗
PubMed1992

Treatment of children with progressive or recurrent brain tumors with carboplatin or iproplatin: a Pediatric Oncology Group randomized phase II study.

PURPOSE: The Pediatric Oncology Group (POG) conducted a randomized phase II study to evaluate the activity of carboplatin and iproplatin in children with progressive or recurrent brain tumors. PATIENTS AND METHODS: The study was designed to evaluate the activity of these agents and to compare the toxicities associated with their use. Treatment consisted of carboplatin 560 mg/m2 at 4-week intervals or iproplatin 270 mg/m2 at 3-week intervals. RESULTS: The major toxicity observed was myelosuppression, particularly thrombocytopenia, for both agents. Ototoxicity (grade 1 or 2) was seen in 2.5% of patients treated with carboplatin and 1.3% of patients treated with iproplatin. The majority of patients with low-grade astrocytic neoplasms treated with carboplatin (nine of 12 patients) or iproplatin (eight of 12 patients) demonstrated tumor response or prolonged stable disease that persisted off-therapy. The duration of stable disease produced by carboplatin was particularly striking, ranging from 2 months to 68 + months (median, 40 + months). Neither drug demonstrated appreciable activity in the treatment of medulloblastoma (two of 26 responses to carboplatin, one of 14 responses to iproplatin), ependymoma (two of 17 responses to carboplatin, none of seven responses to iproplatin), high-grade glioma (two of 19 responses to carboplatin, one of 14 responses to iproplatin), or brain-stem tumors (one of 23 responses to carboplatin, none of 14 responses to iproplatin). CONCLUSION: Carboplatin is active against low-grade gliomas. Further evaluation of the role of carboplatin in the preirradiation treatment of children with low-grade gliomas of the optic pathway is currently underway in a clinical trial.

Adolescent↗
PubMed1991

Hemiparesis and ischemic changes of the white matter after intrathecal therapy for children with acute lymphocytic leukemia.

Three children with acute lymphocytic leukemia (ALL) developed delayed-onset transient hemiparesis and facial palsy after intrathecal (IT) administration of methotrexate (MTX) alone or as part of triple intrathecal chemotherapy for central nervous system (CNS) prophylaxis. The hemiparesis developed 10 to 14 days after IT therapy. Two of three children also experienced transient, profound expressive dysarthria. These episodes occurred during maintenance treatment after multiple IT administrations and without previous CNS toxicity. Two of three children received intermediate-dose MTX, 1 g/m2, not less than 5 weeks before events. These patients had not received cranial irradiation and had no evidence of CNS leukemia before or after these episodes. Ischemic changes on computerized tomographic scan or magnetic resonance imaging studies were documented in all three cases. Such changes are unusual manifestations of neurotoxicity in children after intrathecal therapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

Cytogenetic features of childhood acute lymphoblastic leukemia. A concordance study and a Pediatric Oncology Group study.

Cytogenetic analysis yields important objective information that has been shown to correlate with both patient response to therapeutic intervention and patient survival. Bone marrow samples are submitted to a common reference laboratory for cytogenetic analysis from children with newly diagnosed acute lymphoblastic leukemia (ALL) registered on frontline Pediatric Oncology Group (POG) therapeutic studies (classification 8600 series). A portion of the sample from the Texas Children's Hospital (Houston, TX) a POG affiliate, was also submitted to a local cytogenetics laboratory for analysis. This study retrospectively compares karyotypic data and methods from the Laboratory of Medical Genetics, University of Alabama at Birmingham (reference laboratory) with those of the Kleberg Cytogenetics Laboratory at the Baylor College of Medicine (local laboratory) over a 35-month period to evaluate the effect of differences in specimen procurement, handling, and laboratory methodology on yield of cytogenetic information. Each laboratory was able to identify clonal abnormalities in 72% of cases examined during the last year of the study. When these data were combined, the overall detection rate of clonal abnormalities was 87.5%. Utilizing the same bone marrow aspirate from 73 children, this study demonstrates that cytogenetic methodology significantly affects the yield of identifiable clonal abnormalities, while variables such as overnight shipping have no discernable effect. This study also supports the contention that central laboratory testing effectively yields information critical to ongoing large-scale research endeavors.

Adolescent↗
PubMed1991

Essential thrombocythemia in a child: management with anagrelide.

Essential thrombocythemia (ET) is a rare disorder in children. An 11-year-old white boy was first seen in January 1986 with symptoms of abdominal pain. His platelet count was 1.5 million/mm3. Other hematological values and coagulation studies, including bleeding time, were normal. There was laboratory evidence of mild platelet dysfunction. Using the criteria of the Polycythemia Vera Study Group, a diagnosis of ET was made. He developed frequent headaches. Aspirin was prescribed for the next 2 years at varying doses and frequency. During the period, platelet counts ranged between 1 and 3 million/mm3. In view of progressive headaches and evidence of increasing platelet dysfunction, further treatment was indicated. The use of a new agent, anagrelide, reported effective in adults with ET, resulted in amelioration of symptoms and improvement in quantitative and qualitative platelet control with no significant untoward effects.

Aspirin↗
PubMed1991

Functional deficiency of protein C associated with mesenteric venous thrombosis and splenic infarction.

A 16-year-old girl had abdominal pain, hematemesis, and fever. Radiographic evaluation showed her to have an infarcted spleen and jejunum. Pathologic description revealed thrombi involving the vessels of both organs. A hypercoagulation evaluation of the patient and her family resulted in the diagnosis of hereditary protein C activity deficiency. She is unusual both in the diagnosis of protein C activity deficiency and in her appearance with mesenteric and splenic venous thrombosis. This appearance has not been previously reported in the literature and should be considered in the differential diagnosis of any thrombotic event, even in the face of a negative family history.

Adolescent↗
PubMed1991

cis-platinum ototoxicity in children.

Despite the recognized ototoxicity of cis-platinum, a clinical outline for the audiologic evaluation of patients receiving this drug has not been clearly defined. In a practical approach to this problem, the audiograms of 48 pediatric patients referred for monitoring during planned cis-platinum therapy were reviewed. Eleven patients tested with auditory brain-stem response (ABR) audiometry demonstrated several limitations of this modality. Fourteen children underwent initial ABR testing followed by at least two pure-tone audiograms. The remaining 23 patients had their hearing evaluated by pure-tone audiometry only. Various factors such as patient age, cis-platinum dosage, and cranial radiation exposure were analyzed for apparent effect. Younger patients tended to be more susceptible to audiologic changes with the administration of cis-platinum. The proportion of patients who demonstrated a hearing loss increased with successive dosing as did the severity of the hearing loss. Prior exposure to cranial radiation was strongly linked to the development of hearing loss following cis-platinum therapy. Guidelines are presented regarding the use of clinical audiometry in the screening of these pediatric oncology patients.

Adolescent↗
PubMed1990

Toxicity of high-dose cytosine arabinoside in the treatment of advanced childhood tumors resistant to conventional therapy. A Pediatric Oncology Group study.

Experience with high-dose cytosine arabinoside (HDAC) in pediatric solid tumors is limited. Sixteen children with solid tumors resistant to conventional therapies were registered in a pilot Pediatric Oncology Group (POG) study that required the administration of HDAC at 3 g/m2 every 12 hours for four doses. There were four cases of rhabdomyosarcoma, two cases of fibrosarcoma, four cases of neuroblastoma, and one case each of germ cell tumor, Wilm's tumor, retinoblastoma, hepatocellular carcinoma, Ewing's sarcoma, and Burkitt's lymphoma. All eligible patients had advanced diseases and had previously received extensive chemotherapy. Thirteen patients received one course of HDAC and three patients received two courses of HDAC. Due to prior treatments, patients had less than normal marrow reserves. Short-term toxicity included nausea, vomiting, suppression of hemopoiesis, drug fever, and increased blood urea nitrogen (BUN), creatinine, and liver enzymes. All evaluable patients recovered from their toxicities. There were no drug-related deaths. None of the patients had neurologic problems, including the only patient with prior irradiation to the skull. With the above schedule, HDAC appears to have manageable toxicity.

Child↗
PubMed1990

Primary leptomeningeal B-cell lymphoma in a 8-year-old child.

A case of primary leptomeningeal B-cell lymphoma in an 8-year-old, previously healthy child is described. The child was found to have hypogammaglobulinemia, and the Epstein-Barr virus genome was identified in cultured tumor cells despite blood serology being negative for the virus. The patient was treated with cyclophosphamide, doxorubicin, vincristine, and dexamethasone, plus intrathecal methotrexate, and initially improved. Before the initiation of craniospinal radiation, the patient developed progressive disease, deteriorated, and died 9 months after the onset of symptoms.

Agammaglobulinemia↗
PubMed1990

Typhlitis. An 18-year experience and postmortem review.

A review of pediatric autopsy results at the Texas Children's Hospital, Baylor College of Medicine from 1970 through 1987 was conducted. Thirty-three cases of typhlitis were identified in patients with acute leukemia and two cases each in patients with lymphoblastic lymphoma and aplastic anemia. Patients ranged in age from 10 months to 17 years. Fifty-seven percent were male and 43% were female. All were myelosuppressed. A postmortem incidence rate of 24% was determined for patients with acute leukemia. Common symptoms included abdominal pain and distention in 78% of patients and acute lower gastrointestinal bleeding in 35%. Abdominal radiographs varied in spectrum from a nonspecific bowel gas pattern to frank right colonic pneumatosis intestinalis. Thirty-three patients received chemotherapy within 30 days before onset of abdominal symptoms. All patients were febrile (greater than 38.5 degrees C), and 33 received broad-spectrum antibiotics. Three patients received amphotericin B. Premortem, 84% of organisms cultured from blood were bacterial whereas 16% were fungal. Fungal pathogens accounted for 53% of new microorganisms seen at autopsy. Postmortem examination showed typhlitis in the following anatomic distributions: (1) confined to the cecum; (2) involving the cecum and ileum; (3) involving the cecum, ileum, and ascending colon; or (4) involving the cecum, with sporadic ulcers throughout the intestine. This review includes clinical and postmortem features of typhlitis and current strategies for diagnosis and management.

Adolescent↗
PubMed1990

Bone marrow transplantation in childhood leukemia using reverse isolation techniques.

Between 1979 and 1986, 29 pediatric patients underwent bone marrow transplantation at Texas Children's Hospital using routine reverse isolation. Laminar air flow rooms, prophylactic antibiotics, and gut sterilization were not utilized. The diagnoses included acute lymphocytic leukemia (ALL) (16 patients), acute nonlymphocytic leukemia (ANLL) (10 patients), and chronic myelogenous leukemia (CML) (three patients). All patients had fever during hospitalization. There were 11 episodes of bacteremia in seven patients giving a bacteremia rate of 37.9%. Moderate-to-severe (grade II-IV) acute graft-versus-host disease (GVHD) was seen in eight patients (27.6%). The incidence of infection and GVHD during the first 100 days post-transplantation is comparable to published reports from centers utilizing rigid isolation and sterilization of the gut. It is suggested that bone marrow transplantation may be done using standard reverse isolation techniques without increasing the morbidity or mortality of the procedure.

Adolescent↗
PubMed1990

Phase I evaluation of diaziquone in childhood cancer. A Pediatric Oncology Group study.

We conducted a phase I clinical study of aziridinylbenzoquinone (Diaziquone, AZQ) given as a 4 hour infusion weekly X 4. Forty-five children with recurrent acute leukemia and 33 children with various advanced solid tumors participated. Severe myelosuppression was the dose limiting toxic effect, occurring in all patients at the upper dose levels. Gastrointestinal and hepatic toxicities were infrequent and not severe. No allergic reactions occurred. Objective tumor regression was noted in 3 of 25 patients with a CNS tumor and in 6 of 45 patients with acute leukemia. For phase II trials the recommended dosage of Diaziquone given by this schedule is 18 mg/M2/week X 4 for patients with a solid tumor, and is 30 mg/M2/week X 4 for children with acute leukemia.

Adolescent↗
PubMed1990

Pyoderma gangrenosum in childhood leukemia.

A case of pyoderma gangrenosum (PG) in a 14-year-old boy with acute myelogenous leukemia (AML) is described. The onset of pyoderma gangrenosum coincided with the relapse of AML. The lesions responded dramatically to treatment with oral prednisone despite the persistence of leukemia. Pyoderma gangrenosum should be included in the differential diagnosis of any nodular, pustular, or necrotic cutaneous eruption in children with leukemia.

Adolescent↗
PubMed1989

Low-dose methotrexate-induced changes in intestinal permeability determined by polyethylene glycol polymers.

The impact of chemotherapeutic agents on small bowel mucosa has not been investigated adequately in children. To determine the effect of low-dose methotrexate (MTX) on the permeability and mucosal integrity of the small bowel, we administered low molecular weight polyethylene glycol (PEG) to 19 children who were in the maintenance phase of treatment of acute lymphocytic leukemia. PEG was administered before and after the children received their weekly oral or intramuscular doses of MTX. PEG recoveries from a 6-h urine collection were calculated by a mathematical formula to determine the polymer with maximal recovery (PCD0) and the polymer whose recovery was 50% of PCD0 (N1/2). Compared with pre-MTX levels, a significant increase was observed in the polymer with maximal recovery (PCD0) in 15/19 children after MTX administration (p less than 0.015) which indicated increased transmucosal passage of PEG. A decrease in the PEG parameter (N1/2) was observed in 11/38 studies, and may have indicated diminished enterocyte cell mass. These changes indicate that treatment with MTX results in an increase in intestinal permeability by the paracellular pathway, which may affect the absorption of other molecules.

Adolescent↗
PubMed1989

Gastric leiomyoblastoma (epithelioid leiomyoma) occurring in a child: a case report.

Leiomyoblastomas are rare smooth muscle tumors occurring most commonly in the gastrointestinal tract of adults. We report the unusual occurrence of a gastric leiomyoblastoma in a child who presented with refractory iron deficiency anemia. The tumor had a superficial erosion which was apparently the source of intermittent hemorrhage resulting in anemia. Epithelioid cells, spindled cells, and cells arranged in a perithelial pattern were seen by microscopy, characteristic of a leiomyoblastoma. Immunohistochemical staining demonstrated muscle actin, vimentin, desmin, and alpha-1-antichymotrypsin, and electron microscopy showed focal densities alternating with thin filaments. All of these features help to differentiate the tumor from an inflammatory pseudotumor. Leiomyoblastomas are associated with paragangliomas and pulmonary chondromas in children, but these were not present in this child. The prognosis of leiomyoblastomas may be related to tumor size, mitotic rate, and cellular characteristics.

Child↗