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I J Lewis

Publications and source records attributed to I J Lewis.

At least 55 records · Page 3Linked to original sources
PubMed1994

Changing expression of GTPase activating proteins with differentiation in neuroblastoma.

p21ras is a membrane-associated guanine nucleotide-binding protein with intrinsic GTPase activity. Like other guanine nucleotide-binding proteins p21ras is active when GTP bound and inactive when GDP bound. Phosphorylation of p21ras is regulated by the GTPase activity of type I GAP120 and NF1-GRD. In this study we have identified type I GAP120 and two NF1-GRD mRNAs in three neuroblastoma cell lines, IMR-32, SK-N-SH and SK-N-MC. NF1-GRD mRNA was expressed in all cell lines at a similar level but type I GAP120 mRNA was more abundant in the IMR-32 cell line. Retinoic acid induced differentiation of all three cell lines, this effect was most marked in the SK-N-SH line. This differentiation was accompanied by an increase in both type I GAP120 and NF1-GRD mRNAs. Retinoic acid induced differentiation had no effect on the ratio of type I to type II NF1-GRD mRNA. In seven patient tumour samples examined type I GAP120 and NF1-GRD were coexpressed, type I GAP120 at a higher level than NF1-GRD in all tumour stages. Type I was the predominant NF1-GRD mRNA. The expression of type I GAP120 was similar in all tumour stages but the total level of NF1-GRD was higher in stage 2 and 3 tumours than in stage 4 tumours. In summary, these results suggest increased type I GAP120 and NF1-GRD mRNA are associated with differentiation in neuroblastoma cells.

Base Sequence↗
PubMed1993

Cytogenetic abnormalities in mesoblastic nephroma: a link to Wilms' tumour?

Cytogenetic analysis of tumour material from a congenital mesoblastic nephroma is reported. Two cell lines were found, one with a normal 46,XY karyotype and the other with a hyperdiploid 51,XY karyotype, including a rearrangement of chromosome 11 at 11p15. This finding is of interest since loss of allelic heterozygosity at polymorphic 11p15 loci has been described in sporadic Wilms' tumour [1], and both cytogenetic [2] and molecular [3] changes of 11p15 are found in the Wiedemann-Beckwith syndrome, a condition with a predisposition to embryonal tumours, particularly Wilms' tumour. Our results lead us to speculate on the implications relating to the pathogenesis of this relatively benign tumour variant with respect to the current understanding of the genetics of Wilms' tumour.

Chromosome Deletion↗
PubMed1993

Cisplatin-resistant metastatic hepatoblastoma: complete response to carboplatin, etoposide, and liver transplantation.

A child with stage 4 hepatoblastoma failed to respond to treatment with cisplatin and adriamycin. She then showed a response to carboplatin with complete clearing of pulmonary metastases. Bilobar liver disease persisted, although significantly reduced in size. A liver transplant was subsequently performed and she remains in complete remission 36 months later. After the first course of carboplatin, there was a dramatic rise in alpha-feto protein which then fell exponentially. Carboplatin warrants further study in hepatoblastoma.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1993

Carboplatin pharmacokinetics in children: the development of a pediatric dosing formula. The United Kingdom Children's Cancer Study Group.

PURPOSE: The aim of this study was to define the pharmacokinetics of carboplatin in children and use the data to develop a pediatric dose formula. It was anticipated that renal function would be a major determinant of carboplatin disposition and the relationship between carboplatin clearance and glomerular filtration rate (GFR) was examined in detail. PATIENTS AND METHODS: Plasma carboplatin pharmacokinetics were measured as ultrafiltrable platinum in 22 patients (5 to 63 kg) following 200 to 1,000 mg/m2 of carboplatin. GFR was measured by the plasma clearance of chromium 51-edathamil (51Cr-EDTA). RESULTS: Carboplatin pharmacokinetics in children were best described in most patients (16 of 22) by a two-compartment model. The dose-normalized area under the plasma carboplatin concentration versus time curve (AUC) ranged from 3.1 to 9.6 mg/mL.min/400 mg/m2 and there was only a weak linear relationship between carboplatin dose and AUC (R2 = .31). There was a significant relationship between absolute carboplatin and 51Cr-EDTA clearances (R2 = .56), but the relationship was weaker (R2 = .28) when both clearances were normalized for body surface area. Carboplatin plasma clearance was predicted by the equation: clearance = GFR (mL/min) + 0.36 x body weight (BW; kg), and a modified form of the adult carboplatin dose formula is proposed: dose (mg) = target AUC x (GFR [mL/min] + [0.36 x BW(kg)]). Two further equations were developed that use the 51Cr-EDTA half-life (t1/2) to calculate the GFR and these may reduce errors resulting from inaccurate measurement of the volume of distribution for 51Cr-EDTA. In patients treated with single-agent carboplatin or carboplatin plus vincristine, there was a significant sigmoidal relationship between AUC and thrombocytopenia (R2 = .56). CONCLUSION: GFR-based carboplatin dosing in children should be feasible and will be evaluated prospectively.

Adolescent↗
PubMed1992

Familial microcephaly with normal intelligence in a patient with acute lymphoblastic leukemia.

The authors describe a family with two children with microcephaly and normal intelligence, in which acute lymphoblastic leukemia developed in one of the siblings. An autosomal recessive pattern of inheritance is suggested by the pedigree. This is consistent with the literature, which the authors reviewed. All of the patients have similar phenotypic features, with some demonstrating chromosomal instability. It is important to recognize this syndrome because of the increased risk of lymphoreticular malignancy.

Child↗
PubMed1992

12q13 abnormality in rhabdomyosarcoma. A nonrandom occurrence?

We describe two cases of rhabdomyosarcoma with a translocation involving 12q13 as the primary cytogenetic abnormality. Literature review of 35 cases has identified 3 other cases with this abnormality, and we speculate that this may be another nonrandom rearrangement in rhabdomyosarcoma.

Adolescent↗
PubMed1992

The treatment of resistant neuroblastoma with 131I-mIBG: alternative methods of dose prescription.

A UK multi-centre study has been carried out to collect medical and dosimetry data from treatments with 131I-metaiodobenzylguanidine (mIBG) for patients suffering from resistant neuroblastoma. All data have been acquired in a standardised way, following strict physics and clinical protocols. The accuracy of three different methods of dose prescription was studied. The results show that the most accurate method involved the use of an initial tracer study to determine the therapeutic activity required to deliver a predetermined absorbed whole-body (WB) dose.

3-Iodobenzylguanidine↗
PubMed1992

Interleukin-6 and its relationship to C-reactive protein and fever in children with febrile neutropenia.

The assessment of febrile neutropenia is problematic. C-reactive protein (CRP) values alone do not differentiate those patients with microbiologically documented infections from those with unexplained fevers. Plasma interleukin-6 (IL-6), measured by ELISA, was correlated with different diagnostic groups in 47 episodes of febrile neutropenia in children. Samples were collected daily from admission until resolution of fever. On admission, the median IL-6 value for gram-negative infections was 1610 pg/ml (range, 896-40,000), for gram-positive infections it was 138 pg/ml (range, 66-1045), and for unexplained fevers it was 50 pg/ml (range, 24-135, with a single high value of 665 pg/ml). These medians were significantly different (P less than .005). There was no significant difference in median CRP values. IL-6 values peaked 24-48 h before CRP values. There was a positive correlation of IL-6 with the presence of fever. Plasma IL-6 may be a more sensitive marker than CRP of acute infection and should prove useful in the assessment of fevers in these patients.

Adolescent↗
PubMed1992

Transposition of the gene encoding a TEM-12 extended-spectrum beta-lactamase.

An isolate of Klebsiella oxytoca from the blood culture of a child with leukemia was found to produce two beta-lactamases, at least one of which conferred resistance to ceftazidime. Genes encoding both enzymes were located on a single self-transmissible 100-kb plasmid, pOZ201. This plasmid was introduced into Escherichia coli UB5201 (pACYC184), and the gene encoding one beta-lactamase was transposed onto plasmid pACYC184 by exploiting a gene dosage effect. The transposable gene was found to encode a TEM-12 enzyme as determined by nucleotide sequencing. This gene was subsequently transposed onto plasmid pUB307. The transposable element encoding the TEM-12 enzyme has been designated Tn841. Both plasmids pACYC184::Tn841 and pUB307::Tn841 were shown to encode a beta-lactamase with the same isoelectric point and substrate profile as the TEM-12 beta-lactamase. Transposon Tn841, at approximately 7 kb, is larger than TnA (4.8 kb) and transposes at a lower frequency. Although it produced a resolvase which can complement the resolvase of Tn3, its transposase function was not able to complement the transposition of a TnA element which lacked transposase. The occurrence of a gene encoding an extended-spectrum beta-lactamase on a transposable element in a clinically significant bacterium is potentially a cause for concern for the spread of resistance to the extended-spectrum cephalosporins.

Base Sequence↗
PubMed1992

The intensive care unit in paediatric oncology.

There were 70 admissions from a regional paediatric oncology centre to the intensive care unit over a six and a half year period. Patients were divided into those with systemic infections (n = 19), respiratory infections (n = 15), metabolic effects (n = 9), tumour mass effects (n = 10), neurological complications (n = 8), and others (n = 9). The overall survival was 51%. Patients admitted with metabolic or tumour mass related effects had the best prognosis with a survival of 84%. If dialysis is required in this group of patients then continuous arteriovenous haemofiltration is recommended. Patients with systemic or respiratory infections comprised the main poor prognosis group with a survival of 26%. For patients with a systemic infection who required ventilation, the mortality was 100%. The outlook for patients with a generalised encephalopathy was also poor, with no neurologically intact survivors. The median APACHE-II (acute physiology and chronic health evaluation) score for patients who died was 27 and for survivors was 16. There is a need for close cooperation between staff of intensive care and paediatric oncology units. Alternative treatments should be considered for patients with systemic infections who require ventilation.

Adolescent↗
PubMed1992

Phase I/II study of iodine 131 metaiodobenzylguanidine in chemoresistant neuroblastoma: a United Kingdom Children's Cancer Study Group investigation.

PURPOSE: The goal of this study was to evaluate the toxicity of iodine 131 metaiodobenzylguanidine (mIBG) in metastatic neuroblastoma. PATIENTS AND METHODS: A multicenter phase I study of 131I mIBG has been undertaken by the United Kingdom Children's Cancer Study Group (UKCCSG) in children with advanced chemoresistant neuroblastoma. Activity prescription was based on a prescribed whole-body radiation dose, which was established for individual patients by performing an initial tracer investigation with 75 MBq of 131I mIBG. An activity was derived from this pharmacokinetic study that would deliver an initial whole-body-absorbed radiation dose of 1 Gy. Subsequent dose escalations were based on observed toxicity. RESULTS: Twenty-five patients, aged 1 to 10 years, were treated with prescribed whole-body dose levels of 1.0 Gy (n = 2), 2.0 Gy (n = 13), and 2.5 Gy (n = 10). This necessitated administration of 2.4 to 12.1 GBq of activity. Hematologic, hepatic, kidney, and adrenal toxicity were observed, with bone marrow suppression being the principal dose-limiting toxicity. Bone marrow toxicity increased with prescribed whole-body-absorbed radiation dose, with 80% of patients developing grade 3 or 4 thrombocytopenia at a prescribed whole-body radiation dose of 2.5 Gy. Objective evidence of tumor response was seen in soft tissue (primary or nodal disease), bone, and bone marrow, with an overall response rate of 33% (partial response, n = 8; static disease, n = 9; progressive disease, n = 7). CONCLUSIONS: This study has established an effective method of activity prescription that predicts subsequent toxicity, with the maximally tolerated dose being sufficient activity to deliver a whole-body-absorbed radiation dose of 2.5 Gy. The objective response rate is comparable to other single agents in chemoresistant neuroblastoma and suggests that 131I mIBG may be a useful method for targeting radiotherapy in metastatic neuroblastoma.

3-Iodobenzylguanidine↗
PubMed1992

Prognostic factors in juvenile chronic granulocytic leukaemia.

A retrospective analysis of the clinical and haematological characteristics of patients diagnosed as having juvenile chronic granulocytic leukaemia between 1971 and 1986 was carried out. Thirty-three children were identified who were between the ages of 18 weeks and 8.8 years at diagnosis. The disease was more frequent in boys than girls (23:10). The most common presenting symptoms were skin rash (58%) and bleeding manifestations (45%). All patients had some degree of splenomegaly and in 88% this was more than 3 centimetres below the costal margin. Hepatomegaly and lymphadenopathy were also frequent findings. Anaemia was common and leucocytosis an invariable finding with a white cell count above 50 x 10(9) 1-1 in 42%. Monocytosis was found in 78%. Haemoglobin F measurements were available in 31 children and above 10% in 22 (67%). No child had the Philadelphia chromosome or monosomy 7. Thirty children were treated with chemotherapy, with a variable degree of symptomatic improvement. Twenty-nine patients had died with a median survival time of 5 months. The commonest cause of death was complications of bone marrow failure and no child developed acute leukaemia. Presenting characteristics associated with a longer survival period were age less than 6 months (P = 0.02), female sex (P = 0.02), HbF less than 10% (P = 0.0004) and the absence of bleeding manifestations (P = 0.03). We conclude that the prognosis for children aged over 6 months, with a raised HbF level is very poor, and that, in the absence of possible bone marrow transplantation, consideration should be given to novel treatment approaches for these patients.

Antineoplastic Agents↗
PubMed1992

Spontaneous regression of neonatal fibrosarcoma.

We report a case of fibrosarcoma, which presented in a two week old boy. Excision was not performed because it would have required mutilating surgery. The tumour regressed and was impalpable by 7 months of age. The patient is tumour free at 4 years of age. This is the first reported case of spontaneous regression of a fibrosarcoma. The literature is reviewed. We conclude that the chances of metastasis are low, tumours are likely to respond to chemotherapy, and mutilating surgery is not appropriate initial treatment for infantile fibrosarcomas.

Bone Neoplasms↗
PubMed1991

Childhood cancer and ethnic group in Britain: a United Kingdom children's Cancer Study Group (UKCCSG) study.

We present here the results of the largest study of childhood cancer and ethnic group in Britain, based on 7,658 children treated at paediatric oncology centres throughout the country. Incidence rates could not be calculated and so relative frequencies were analysed by the log-linear modelling method of Kaldor et al. (1990) with allowance made for regional variations in the ages and diagnostic groups of the children included in the study. Children of Asian (Indian sub-continent) and West Indian ethnic origin had similar patterns of incidence for acute lymphoblastic leukaemia to White Caucasians. There was a significant excess of Hodgkin's disease among Asian children compared with Caucasians with an estimated relative risk (RR) of 2.09; this excess was greatest in the 0-4 age group (RR = 6.67). There were significant deficits of Wilms' tumour and rhabdomyosarcoma among Asian children, each with a frequency around half that among Caucasians, whereas West Indians had a significant excess of Wilms' tumour (RR = 2.55). Asian and West Indian children each had a non-significant twofold RR for unilateral retinoblastoma. The results suggest that the incidence of childhood acute lymphoblastic leukaemia is associated with environmental determinants in the country of residence which are most likely to relate to lifestyle factors. The occurrence of retinoblastoma, Wilms' tumour and Hodgkin's disease in early childhood is apparently related more to ethnicity than to geographical location and may reflect genetic factors or environmental exposures specific to the lifestyle of particular ethnic groups.

Central Nervous System Neoplasms↗
PubMed1991

Aztreonam therapy in children with febrile neutropenia: a randomized trial of aztreonam plus flucloxacillin versus piperacillin plus gentamicin.

In a prospective, randomized trial in 100 febrile neutropenic children, aztreonam plus flucloxacillin was compared with piperacillin plus gentamicin. At the 72 h clinical assessment there was no statistically significant difference between the two groups. However, in microbiologically documented infections there was a higher response rate in the piperacillin/gentamicin group (57%) than in the aztreonam/flucoxacillin group (41%). This was contributed to by the poorer Gram-positive cover of the aztreonam/flucloxacillin combination. In clinically documented infections and unexplained fevers the response rate of the two antibiotic regimens was identical. There were two deaths; one early death (in the piperacillin/gentamicin arm) and one late death. At the final assessment a successful outcome was obtained in the remaining patients. In the aztreonam/flucloxacillin group 75% of the episodes required modification compared with 59% in the piperacillin/gentamicin group.

Adolescent↗