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Biomedical subjects

P Brock

Publications and source records attributed to P Brock.

At least 37 records · Page 2Linked to original sources
PubMed1997

Systemic effect of intrathecal methotrexate during the initial phase of treatment of childhood acute lymphoblastic leukemia. The European Organization for Research and Treatment of Cancer Children's Leukemia Cooperative Group.

PURPOSE: The in vivo response to prephase corticosteroid therapy for 1 week has been described as a major prognostic factor in childhood acute lymphoblastic leukemia (ALL). Patients with less than 1,000 blasts/microL at day 8 are considered responders and have a better prognosis. This prephase therapy is usually considered as an evaluation of glucocorticoid sensitivity. In fact, it also includes one intrathecal (IT) injection of methotrexate (MTX). In this study, we try to clarify the influence of this injection of IT MTX on the response to the prephase therapy. PATIENTS AND METHODS: This retrospective study analyzed the response to prephase therapy in 1,044 children with ALL entered onto the European Organization for Research and Treatment of Cancer (EORTC) trial 58881 of the Children's Leukemia Cooperative Group (CLCG). Analysis was restricted to 732 cases with an initial blast count greater than 1,000/microL. The following variables were tested to analyze response to prephase therapy: age, sex, evaluated risk factor (RF), blast count on day 0, actual dose of prednisolone administered, immunophenotype (T v non-T), and day of IT MTX. For statistical analysis, the variable day of IT MTX (D) was stratified into three groups: group 1 if D less than 2, group 2 if D > or = 2 but < or = 6, and group 3 if D greater than 6. RESULTS: All variables tested had a significant influence on response to the prephase therapy. This was especially true for IT MTX: 90.4% responders in group 1, 76.9% in group 2, and 70% in group 3 (P < .001). Immunophenotype was also a major predictor of response to the prephase: 88% responders in B-lineage ALL versus 56.2% in T-lineage ALL. IT MTX had a significant influence in B-lineage ALL (96% responders in group 1, 90% in group 2, and 79% in group 3; P < .001), whereas the influence could not be detected in T-lineage ALL. CONCLUSION: These results clearly demonstrate a therapeutic systemic effect of low doses of IT MTX in childhood ALL, and response to prephase therapy should not be considered as an in vivo test for cortico-sensitivity only. Earlier use of IT MTX leads to a higher percentage of responders.

Antimetabolites, Antineoplastic↗
PubMed1997

Cutaneous involvement in children with acute lymphoblastic leukemia or lymphoblastic lymphoma. The Children's Leukemia Cooperative Group of the European Organization of Research and Treatment of Cancer (EORTC).

OBJECTIVE: Skin involvement in children with acute monocytic leukemia or CD30-positive anaplastic large-cell lymphoma is well-known. In contrast, very little is known about the malignant cutaneous infiltrates in children with acute lymphoblatic leukemia (ALL) or lymphoblastic lymphoma (LBL). This study was designed to determine the frequency of these specific lesions in childhood ALL or LBL and the characteristics of such patients. DESIGN: We studied the clinical and biological findings of children with cutaneous involvement at initial diagnosis of ALL or LBL enrolled between August 1989 and March 1995 in the multicentric trial 58881 of the Children's Leukemia Cooperative Group of the European Organization of Research and Treatment of Cancer (EORTC). RESULTS: Among the 1359 children enrolled in the multicenter trial EORTC 58881, 24 presented with skin involvement at diagnosis. ALL was diagnosed in 15 patients and LBL in 9. In 15 cases, skin lesions were observed within a median time of 6 weeks (range, a few days to 8 months) before the diagnosis of the hematologic disease. Twenty-one children had at least one skin lesion located on the head. Diffuse cutaneous lesions were observed in 7 infants with high-risk ALL. Seventeen of the 24 children remain in the first complete remission (median follow-up of 3 years; range 2 months to 5 years) and 3 are in the second remission with a follow-up of 14 to 24 months. CONCLUSION: The present study demonstrates that cutaneous involvement can be an early manifestation of ALL or LBL. Cutaneous leukemic infiltrates can be observed in children with standard risk as well as in high-risk ALL. Cutaneous involvement in children with LBL is mainly associated with a B-cell precursor immunophenotype of the lymphomatous cells. The most frequent location of skin lesions in children with ALL or LBL is on the head. Further studies are needed to evaluate the prognosis of children with such involvement at diagnosis.

Age Factors↗
PubMed1996

Light-directed synthesis of high-density oligonucleotide arrays using semiconductor photoresists.

High-density arrays of oligonucleotide probes are proving to be powerful new tools for large-scale DNA and RNA sequence analysis. A method for constructing these arrays, using light-directed DNA synthesis with photo-activatable monomers, can currently achieve densities on the order of 10(6) sequences/cm2. One of the challenges facing this technology is to further increase the volume, complexity, and density of sequence information encoded in these arrays. Here we demonstrate a new approach for synthesizing DNA probe arrays that combines standard solid-phase oligonucleotide synthesis with polymeric photoresist films serving as the photoimageable component. This opens the way to exploiting high-resolution imaging materials and processes from the microelectronics industry for the fabrication of DNA probe arrays with substantially higher densities than are currently available.

Base Sequence↗
PubMed1996

Biallelic alterations of both ETV6 and CDKN1B genes in a t(12;21) childhood acute lymphoblastic leukemia case.

Recently, a new recurrent t(12;21)(pl3;q22) has been identified in a B-cell lineage childhood acute lymphoblastic leukemia (ALL). The translocation results in a fusion of two known genes, ETV6/TEL (12p13) and AML1 (21q22), previously shown to be involved in the pathogenesis of myeloid disorders. We report results of cytogenetic fluorescence in situ hybridization and molecular studies of a B-cell childhood common ALL with a cryptic 12;21 translocation. Aberrations identified in this case involve both chromosomes 12 and include not only the ETV6-AML1 gene fusion and two different microdeletions of ETV6 but also the hemizygous loss of CDKN1B, D12S119, and KRAS2 loci and a putative rearrangement of the second CDKN1B allele as a result of an inv(12)(p13q24). Moreover, it was shown that the AML1-ETV6 reciprocal chimeric transcript was not present in the malignant cells, and hence may not play a major role in leukemogenesis. In addition, the putative loss of wild-type function of CDKN1B and ETV6 could indicate a synergistic effect of both genes in the pathogenesis of this leukemia case.

Adolescent↗
PubMed1996

Juvenile fibrosarcoma of the temporal bone.

A case of juvenile fibrosarcoma arising from the head and neck region is described. This type of tumour should be considered as a separate entity different from the fibrosarcoma in adults because of the different clinical behaviour. The symptomatology, the radiographic features and the literature data are reviewed.

Child, Preschool↗
PubMed1996

An increased loading dose of ondansetron: a north european, double-blind randomised study in children, comparing 5 mg/m2 with 10 mg/m2.

A North European, randomised, double-blind study, comparing a loading-dose of ondansetron of 5 mg/m2 with 10 mg/m2, administered intravenously before highly emetogenic chemotherapy, was carried out in 187 chemotherapy-naïve children. In the first 24 h, both groups received further ondansetron intravenously at a dose of 5 mg/m2 8-hourly. Thereafter, ondansetron was given at an oral dose of 4 or 8 mg depending on the surface area of the child, three times a day and continued for at least 3 days after the last day of chemotherapy. There was no difference in the control of emesis between the two groups. Ondansetron provided good control of emesis and nausea on day 1 with 71-72% of patients experiencing two or fewer emetic episodes (complete or major responders) and 90-86% of patients reporting nausea as none or mild. There was also no difference in the efficacy of the treatment arms in the control of emesis and nausea on subsequent days of the study period. Both anti-emetic regimens were well-tolerated.

Adolescent↗
PubMed1995

[Transient erythroblastopenia in 4 children].

In four patients, all girls, aged 2, 3.5, 4 and 5 years, transient erythroblastopenia was diagnosed. The children were presented because of acute pallor. The haemoglobin levels were 2.8 to 5.0 mmol/l. After 3 weeks all patients had recovered or were recovering with increasing haemoglobin values. Three of the four patients needed one blood transfusion. In two patients there was evidence of a parvovirus B19 infection. Transient erythroblastopenia is mostly seen in patients aged 1-4 years. Most cases are postinfectious and there is evidence that human parvovirus B19 is responsible for many cases. In the very young child the differential diagnosis from Blackfan-Diamond anaemia may be very difficult.

Blood Transfusion↗
PubMed1995

Consecutive glioblastoma and B cell non-Hodgkin's lymphoma in a young child with von Recklinghausen's Neurofibromatosis.

A young child with neurofibromatosis type 1 (NF1) is reported who developed two primary malignancies: a glioblastoma, followed 6 months later by an abdominal B cell non-Hodgkin's lymphoma. The child is now 4.5 years off treatment and disease free, but has developed progressive and severe psychomotor retardation as sequelae. The NF1 gene is known to act as a tumor suppressor gene. The possible mechanisms leading to the occurrence of a second primary tumor in this child are discussed.

Abdominal Neoplasms↗
PubMed1995

5q- syndrome in a child.

A boy aged 8 years, 10 months presented with refractory anemia. Bone marrow investigation revealed monolobular megakaryocytes. Cytogenetic analysis showed a clonal abnormality: 46, XY, del(5)(q14q32). This is the youngest individual ever reported with this disorder. A year after diagnosis, while on treatment with human recombinant erythropoietin, the bone marrow showed an excess of blasts. No bone marrow donor could be found. Transformation to acute myelomonocytic leukemia occurred 3 months later. In spite of intensive chemotherapy, the child died of progressive disease with massive splenomegaly and jaundice. The case illustrates that the 5q- syndrome can occur de novo in children. The outcome in this child was poor, which may reflect a difference from the adult 5q- syndrome or may possibly be related to the erythropoietin the child received.

Anemia, Refractory↗
PubMed1994

Successful treatment of recurrent thrombotic thrombocytopenic purpura with plasmapheresis and vincristine.

An adolescent girl with severe thrombotic thrombocytopenic purpura (TTP) remained in a critical condition after 3 weeks of combined treatment with antiplatelet drugs, plasma infusions and plasma exchange. The introduction of vincristine resulted in gradual improvement and eventual complete remission which lasted for 2 years. When she relapsed, immediate improvement was observed with the combined treatment of plasmapheresis and vincristine. She has now been in complete remission again for 10 months. It is suggested that plasmapheresis plus vincristine should be used as the initial treatment for children with TTP.

Adolescent↗
PubMed1994

Pleuropulmonary blastoma (pulmonary blastoma of childhood): genetic link with other embryonal malignancies?

A case of pleuropulmonary blastoma (childhood variant of pulmonary blastoma) was examined using histological, immunohistochemical, ultrastructural and cytogenetic methods. The tumour consisted of undifferentiated 'blastematous' areas admixed with zones of rhabdomyoblastic and chondroid differentiation and fascicular areas. Desmin and S-100 protein immunoreactivity confirmed the myogenic and cartilaginous differentiation. Ultrastructurally only undifferentiated mesenchymal cells were present. The cytogenetic analysis revealed abnormalities of 2q. Involvement of 2q has also been described in hepatoblastoma and embryonal rhabdomyosarcoma. Although further confirmation is needed, our cytogenetic findings in pleuropulmonary blastoma suggest common genetic mechanisms in some paediatric embryonal malignancies.

Biopsy↗
PubMed1993

Non-endemic Burkitt's lymphoma in a patient with Bloom's syndrome.

Bloom's syndrome is an autosomal recessive disorder characterized by intrauterine growth retardation, typical physical signs, immunodeficiency and an increased risk of developing neoplasms at a young age, compared to the general population. Factors possibly involved in the pathogenesis of non-endemic Burkitt's lymphoma in a five year old girl with Bloom's syndrome are discussed. These include immunodeficiency, upregulated c-myc expression and an Epstein-Barr viral infection.

Bloom Syndrome↗
PubMed1992

Reversible hypophosphatemic rickets following ifosfamide treatment.

A 7-year-old boy developed renal tubular dysfunction and hypophosphatemic rickets following treatment for relapsed embryonal rhabdomyosarcoma. Multi-agent chemotherapy included ifosfamide; the child received a total of 108 g/m2. The complete Fanconi syndrome which ensued, including excessive loss of calcium, resolved spontaneously and progressively 18 months after the last dose of ifosfamide. The patient had no further symptoms of rickets and radiological signs had almost completely normalized. Further follow-up was not possible as, despite further treatment, the child died of progressive disease.

Abdominal Neoplasms↗
PubMed1992

Sudden blindness in a child: presenting symptom of a sphenoid sinus mucocele.

A 10-year-old girl with no nasal or respiratory symptoms developed a headache lasting a few hours. The next day she became totally blind in the right eye and over 5 days vision in the left eye deteriorated to bare light perception. The diagnosis of a sphenoid sinus mucocele was made radiologically and drainage via an endonasal sphenoidectomy produced 12 ml of brownish fluid. Endoscopic biopsy of the wall confirmed the diagnosis of a mucocele. Steroid treatment was given postoperatively, but vision recovered to 6/12 in the left eye only. The importance of urgent clinical diagnosis and treatment is stressed.

Acute Disease↗