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The accurate assessment of disease risk among children with medulloblastoma remains a major challenge to the field of paediatric neuro-oncology. In the current study we investigated the capacity of molecular abnormalities to increase the... more
The accurate assessment of disease risk among children with medulloblastoma remains a major challenge to the field of paediatric neuro-oncology. In the current study we investigated the capacity of molecular abnormalities to increase the accuracy of disease risk stratification above that afforded by clinical staging alone. 41 primary medulloblastoma tumour samples were analysed for ErbB2 receptor expression using immunohistochemistry, and for aberrations of chromosome 17 and amplification of the MYC oncogene using fluorescence in situ hybridisation. The ErbB2 receptor and deletion of 17p were detected in 80% and 49% of tumours, respectively. 17p loss occurred either in isolation (20%), or in association with gain of 17q (29%), compatible with an isochromosome of 17q. Amplification of MYC was detected in only 2 tumours. Significant prognostic factors included, 'metastatic disease' (P = 0.0006), 'sub-total tumour resection' (P = 0.007), 'high ErbB2 receptor express...
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Background:MYCN is the most commonly amplified gene in human neuroblastomas. This proto-oncogene has been overexpressed in a mouse model of the disease in order to explore the role of MYCN in this tumour.Aims:To report the... more
Background:MYCN is the most commonly amplified gene in human neuroblastomas. This proto-oncogene has been overexpressed in a mouse model of the disease in order to explore the role of MYCN in this tumour.Aims:To report the histopathological features of neuroblastomas from MYCN transgenic mice.Methods:27 neuroblastomas from hemizygous transgenic mice and four tumours from homozygous mice were examined histologically; Ki67 and MYCN immunocytochemistry was performed in 24 tumours.Results:Tumours obtained from MYCN transgenic mice resembled human neuroblastomas, displaying many of the features associated with stroma-poor neuroblastoma, including heterogeneity of differentiation (but no overt ganglionic differentiation was seen), low levels of Schwannian stroma and a high mitosis karyorrhexis index. The tumours had a median Ki67 labelling index of 70%; all tumours expressed MYCN with a median labelling index of 68%. The most striking difference between the murine and human neuroblastomas...
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Research Interests: Flow Cytometry, Survival Analysis, Adolescent, Signal Transduction, Multivariate Analysis, and 15 moreMitosis, Humans, Child, Medulloblastoma, Close relationships, Female, Male, Infant, European, Prognosis, Indexation, Mitotic Index, Adjuvant Chemotherapy, Growth factor receptor, and Child preschool
Primitive neuroectodermal tumours (PNET's) or medulloblastomas are common primary brain tumours of childhood. Current treatment protocols achieve 50-60% cures. However, it has proved difficult to develop better treatment for the... more
Primitive neuroectodermal tumours (PNET's) or medulloblastomas are common primary brain tumours of childhood. Current treatment protocols achieve 50-60% cures. However, it has proved difficult to develop better treatment for the remaining patients because prognostic factors are not established. We have investigated the prognostic value of p53 protein expression in 87 PNET's using immunohistochemistry with DO-7 and CM-1 antibodies on biopsy paraffin sections. Eight patients (9%) had intensely reactive tumour cell nuclei, and a significantly reduced survival (P = 0.002); only one survives and this with a recurrent tumour 50 months following diagnosis. Sixty eight per cent of patients had faintly reactive tumour cell nuclei, a reduced survival up to 4 years but a long term survival not significantly different (P = 0.41) from 23% of patients with p53 negative PNET's; the 10 year survival rates were 37% and 40%, respectively. Males had a reduced survival (P = 0.04) with a 2-f...
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HeLa-S3 cells were treated with heat and/or radiation in medium of pH 7.4 or pH 6.7. A heat treatment at 44 degrees C for 10 min, which alone did not produce any measurable cell killing, was found to enhance the lethal effect of radiation... more
HeLa-S3 cells were treated with heat and/or radiation in medium of pH 7.4 or pH 6.7. A heat treatment at 44 degrees C for 10 min, which alone did not produce any measurable cell killing, was found to enhance the lethal effect of radiation to the same extent at pH 6.7 and 7.4. Heat alone at 44 degrees C for 30 min killed 65 per cent of cells at pH 7.4 and 90 per cent at pH 6.7 and produced a marked radiation sensitization of the survivors but only slightly more at pH 6.7 than at pH 7.4. These results support the suggestion that heat damage responsible for increase in sensitivity to subsequent irradiation is distinguishable from damage which leads to cell death after heat alone, and that heat used as a radiation sensitizer may only give a small therapeutic gain in cancer treatment, based on the lower pH of some tumour cells.
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To examine retrospectively the prognostic significance of TP53 immunoreactivity for both tumor response and patient survival in 83 patients with nonmetastatic muscle-invasive bladder cancer treated with a single transurethral resection... more
To examine retrospectively the prognostic significance of TP53 immunoreactivity for both tumor response and patient survival in 83 patients with nonmetastatic muscle-invasive bladder cancer treated with a single transurethral resection (TUR) of tumor and combined cisplatin-based systemic chemotherapy followed by repeat TUR, paraffin-embedded sections of a bladder tumor obtained at TUR before chemotherapy (1 T2, 52 T3, and 30 T4) were immunostained for TP53 using monoclonal PAb1801 and DO-7 antibodies. For the entire cohort, TP53 immunopositivity (PAb1801 or DO-7) did not predict complete response (CR), complete or partial response (PR), progressive disease, or time to death from bladder cancer. There was a highly significant correlation between PAb1801 and DO-7 nuclear immunoreactivity (r = 0.8242; P<0.0001). In 76 patients in which complete clinical data were available, tumor stage (T2/T3; P = 0.0499), CR and PR (P = 0.0016) and CR (P<0.0001) were associated with patient surv...
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E. coli Bs-1 cells were exposed to acute doses of tritium-beta particles by suspension in tritiated water for known lengths of time. The resulting survival rate was compared with that obtained for external irradiation with 7 MeV... more
E. coli Bs-1 cells were exposed to acute doses of tritium-beta particles by suspension in tritiated water for known lengths of time. The resulting survival rate was compared with that obtained for external irradiation with 7 MeV electrons. The o.e.r. measured for tritium-beta s was not significantly different from the value of 2.15 measured for 7 MeV electrons. The r.b.e. of the tritium beta s relative to 7 MeV electrons was 1.21 in both air and nitrogen. These results were compared with existing data for low voltage electron irradiations and with track segment studies of the effect of varying LET on the radiosensitivity of E. coli Bs-1.
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The effect of EGF and gefitinib on two EGFR-positive human bladder cancer cell lines has been investigated using array-based gene expression profiling. The most prominent transcript, increased up to 6.7-fold by EGF compared with controls... more
The effect of EGF and gefitinib on two EGFR-positive human bladder cancer cell lines has been investigated using array-based gene expression profiling. The most prominent transcript, increased up to 6.7-fold by EGF compared with controls in RT112 cells, was human early growth response protein 1 (hEGR1). This induction was prevented by gefitinib. The hEGR1 mRNA in EGF-treated samples was reduced in the presence of gefitinib, as was hEGR1 protein in cell lysates. In the RT4 cells, hEGR1 expression was halved in the presence of EGF and gefitinib in combination. In bladder tumour samples, there was a significant correlation between hEGR1 mRNA detected by RT-PCR and EGFR detected by ligand binding, (P=0.042). The induction by EGF of the hEGR1 gene, mRNA and protein in RT112 cells, and its inhibition by gefitinib, together with the detection of hEGR1 mRNA in bladder tumours, suggests that hEGR1 may be important in the EGFR growth-signalling pathway in bladder cancer and should be further ...
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p53 mutations are rare in neuroblastomas at diagnosis perhaps accounting for their initial response to therapy, but advanced neuroblastoma frequently relapses, and it is possible that p53 mutations develop later. Two neuroblastoma cell... more
p53 mutations are rare in neuroblastomas at diagnosis perhaps accounting for their initial response to therapy, but advanced neuroblastoma frequently relapses, and it is possible that p53 mutations develop later. Two neuroblastoma cell lines derived from the same patient before [SKNBE(1n)] and after [SKNBE(2c)] cytotoxic therapy were analyzed for the presence of chromosome 17 and p53 genes by fluorescent in situ hybridization, p53 mutations by DNA sequencing, and p53 function after irradiation by studying the transcription of p53-regulated genes, cell cycle arrest, and induction of apoptosis. The SKNBE(1n) cell line was wild-type for p53, had two p53 genes, two copies of chromosome arm 17p and showed functional p53 after irradiation. The SKNBE(2c) cell line derived from the same patient 5 months later at relapse had loss of an entire chromosome 17, resulting in hemizygosity for the p53 locus on 17p and a missense p53 mutation in exon 5, and p53 was not functional after irradiation. ...
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The matrix metalloproteinases are a family of enzymes that degrade the extracellular matrix and are considered to be important in tumour invasion and metastasis. The effect of epidermal growth factor (EGF) on matrix metalloproteinase-1... more
The matrix metalloproteinases are a family of enzymes that degrade the extracellular matrix and are considered to be important in tumour invasion and metastasis. The effect of epidermal growth factor (EGF) on matrix metalloproteinase-1 (MMP1) production in two human bladder tumour cell lines, RT112 and RT4, has been investigated. In the RT112 cell line, an increase in MMP1 mRNA levels was found after a 6-h incubation with EGF, and this further increased to 20-fold that of control levels at 24- and 48-h treatment with 50 ng ml(-1) of EGF. MMP2 mRNA levels remained constant over this time period, whereas in the RT4 cells no MMP2 transcripts were detectable, but MMP1 transcripts again increased with 24- and 48-h treatment with 50 ng ml(-1) of EGF. MMP1 protein concentration in the conditioned medium from both cell lines increased with 24- and 48-h treatment of the cells and the total MMP1 was higher in the medium than the cells, demonstrating that the bladder tumour cell lines synthesi...
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We have used microdissection of paraffin-embedded histological sections and polymerase chain reaction (PCR)-based direct DNA sequencing for 54 transitional cell carcinoma (TCC) of the bladder, to examine critically the association between... more
We have used microdissection of paraffin-embedded histological sections and polymerase chain reaction (PCR)-based direct DNA sequencing for 54 transitional cell carcinoma (TCC) of the bladder, to examine critically the association between TP53 nuclear accumulation determined by immunohistochemistry and the presence of TP53 mutations, and to examine their relationship to tumour stage and grade, as well as patient survival. There was a significant association between the presence of TP53-positive nuclei (> 10%) and a higher histological stage and grade (P = 0.0115, P = 0.0151 respectively; Fisher's exact). A significant association between TP53 gene mutations and TP53 nuclear reactivity in more than 10% of tumour cell nuclei was also observed (P = 0.0003; Fisher's exact). Mutations were detected in 18/54 (33%) cases together with the wild-type sequence when analysed from bulk frozen samples, with significant clustering of mutations in exons 7 and 8. The microdissection meth...
Research Interests: Immunohistochemistry, Apoptosis, Nature, Cell Division, High Frequency, and 15 moreAdipose tissue, Humans, Mutation, Correlation, Microdissection, Polymerase Chain Reaction, Statistical Significance, Mutation Detection, Dissection, Prognosis, Cancer cells, Cancers, DNA sequence, Survival curve, and Confidence Level
Overexpression of the multidrug resistance (mdr1) gene has been implicated in resistance to a number of the chemotherapeutic agents currently used in the treatment of bladder cancer (doxorubicin, vincristine and epirubicin). We report the... more
Overexpression of the multidrug resistance (mdr1) gene has been implicated in resistance to a number of the chemotherapeutic agents currently used in the treatment of bladder cancer (doxorubicin, vincristine and epirubicin). We report the development and validation of a quantitative assay for the determination of mdr1 gene transcript levels based on reverse transcription and the polymerase chain reaction (PCR), sensitive to less than 2-fold variations in transcript levels. Using these techniques, mdr1 mRNA levels were investigated in 32 primary untreated transitional cell carcinomas of the bladder. mdr1 mRNA was detected in all samples, with levels varying between individual tumours over a 63-fold range. These variations were not associated with the proliferative status of the tumour. mdr1 mRNA levels were significantly higher in poorly differentiated high-grade (G3) tumours than in well- and moderately differentiated low-grade (G1 and G2) tumours (P = 0.0057). The results suggest t...
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There is substantial evidence that ADP-ribosylation is stimulated in response to DNA strand breaks produced directly by a damaging agent or during excision repair processes. The report of a reduced stimulation of ADPRT activity in... more
There is substantial evidence that ADP-ribosylation is stimulated in response to DNA strand breaks produced directly by a damaging agent or during excision repair processes. The report of a reduced stimulation of ADPRT activity in irradiated ataxia telangiectasia cells has recently stimulated a wide interest in the role of ADP-ribosylation in cellular radiation response. The resulting studies, some of which are presented at this conference, demonstrate that cellular recovery from radiation damage can be significantly impaired if ADP-ribosylation is inhibited to a sufficiently low level. The implication is that the repair of DNA lesions is affected. This review summarizes the involvement of the enzyme ADPRT and the extent of ADP-ribosylation in the repair of DNA damage and of cellular recovery.
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The prognostic value of p21 and p53 expression was evaluated for patients with muscle-invasive bladder cancer treated by radical radiotherapy. Sixty-eight paraffin-embedded sections from surgically resected tumors taken prior to... more
The prognostic value of p21 and p53 expression was evaluated for patients with muscle-invasive bladder cancer treated by radical radiotherapy. Sixty-eight paraffin-embedded sections from surgically resected tumors taken prior to irradiation were immunostained for p21 and p53. Nuclear staining for p21 and p53 was demonstrated in 32/68 (47%) and 46/68 (68%) tumors, respectively. There was no correlation between p21 and p53 immunopositivity in this group (r = 0.067, p = 0.56). Patients were stratified into four distinct groups depending on staining for p21 and p53: p21+p53+, p21+p53-, p21-p53+, and p21-p53-. Patients with p21+p53+ tumors had the best prognosis with a 3-year survival of 82% compared to 12% for p21-p53+ tumors (p = 0.0031), 29% for p21+p53- tumors (p = 0.0108); and 45% for p21-p53- tumors (p = 0.0375). The p21+p53+ group also demonstrated significantly improved survival when a combined analysis was performed of p21-p53+, p21-p53-, and p21+p53- tumors (3-year survival = 30%, p = 0.0062). In a multivariate model, p21+p53+ tumors (p = 0.0108, relative risk [RR] = 5.18) and complete/partial response (p = 0.0019, RR = 3.76) were the only independent predictors of improved survival. With muscle-invasive bladder tumors treated by radical radiotherapy, stratification for p21 and p53 identifies distinct prognostic groups, with p21+p53+ tumors being associated with the best survival and p21-p53+ the worst.
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... in the incident sound field will respond strongly and at 1 . 5 MHz resonant bubbles have a radius of 2. 3 microns (Coakley and Nyborg 1978) . ... The labelling was for one and a half divisions followed by a chase in fresh medium with... more
... in the incident sound field will respond strongly and at 1 . 5 MHz resonant bubbles have a radius of 2. 3 microns (Coakley and Nyborg 1978) . ... The labelling was for one and a half divisions followed by a chase in fresh medium with cold thymidine over a quarter of a division . ...
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Research Interests: Information Systems, Genetics, Genomics, Humans, Animals, and 15 morePolymerase Chain Reaction, DNA hybridization, Genetic Map, Biological evolution, Human Genome, Genomic DNA, Fluorescent in situ hybridization, Cysteine endopeptidases, Amino Acid Sequence, Base Sequence, Glutamate Dehydrogenase, DNA probes, DNA sequence, Molecular Sequence Data, and Cricetinae
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Research Interests: Genetics, Cell line, Humans, Human Genome Project, Gene, and 13 moreGenes, Neuroblastoma, Introns, Molecular cloning, Genomic DNA, Fluorescent In-Situ Hybridisation, Base Sequence, Open Reading Frame, Molecular Sequence Data, cDNA cloning, Neoplasm staging, gene amplification, and conserved sequence
Gastroenterology, Volume 120, Issue 5, Pages A300, April 2001, Authors:Ihab AM Ahmed; Ghassan S. Nouman; John Lunec; Seamus B. Kelly; John J. Anderson; Brian Angus.
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Identification of biological markers that may predict response to chemotherapy would allow the individualization of treatment by enabling selection of patients most likely to benefit from chemotherapy. The aims of this study were to... more
Identification of biological markers that may predict response to chemotherapy would allow the individualization of treatment by enabling selection of patients most likely to benefit from chemotherapy. The aims of this study were to determine whether p53 mutation status and p53 and p33(ING1b) protein expression can predict which patients with Dukes&amp;amp;amp;amp;amp;amp;#39; C colorectal cancer following curative surgical resection respond to adjuvant chemotherapy with 5-fluorouracil (5-FU). Patients with Dukes&amp;amp;amp;amp;amp;amp;#39;C colorectal cancer (n = 41) were studied. DNA was extracted and analysed for p53 mutation using PCR-based direct DNA sequencing. Tumours were analysed for p53 protein expression by immunohistochemistry using DO-7 monoclonal antibody and for p33(ING1b) protein expression using GN1 monoclonal antibody. There was a significant association between p53 mutation status analysed by gene sequencing and overall and metastasis-free survival (P = 0.03 and 0.004, respectively, log-rank test). By contrast, no significant correlation was found between p53 and p33(ING1b) protein expression and overall or metastasis-free survival. In patients with Dukes&amp;amp;amp;amp;amp;amp;#39;C colorectal cancer who underwent curative surgical resection of the primary tumour, followed by 5-FU-based adjuvant chemotherapy, p53 mutation status as assessed by gene sequencing is a significant predictor of overall and metastasis-free survival.
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To determine the frequency of mutations of the H-ras gene in transitional cell carcinomas of the human urinary bladder using direct DNA sequencing based on the polymerase chain reaction (PCR) method and to compare the results with those... more
To determine the frequency of mutations of the H-ras gene in transitional cell carcinomas of the human urinary bladder using direct DNA sequencing based on the polymerase chain reaction (PCR) method and to compare the results with those of other methods. In addition, the relationship of the mutation frequency to tumour stage and grade was examined. Bladder tumour samples, taken by cystoscopic resection from 50 patients with newly diagnosed transitional cell carcinoma of the urinary bladder, were analysed by PCR-based direct DNA sequencing for point mutations in the H-ras gene at codon 12. Point mutations were found in 9 of 50 tumours examined (18%). The most frequent mutation (8/9) was a G to T transversion converting GGC to GTC, which would result in a glycine to valine substitution. The remaining mutations was a G to A transition altering GGC to GAC, producing a glycine to aspartic acid substitution, which has not previously been reported in bladder cancer. In all tumour samples examined the wild-type allele (GGC) was also evident. Variation in the proportion of wild-type to mutated sequence was found within tumour samples. No relationship between mutations and tumor grade and stage was apparent. The frequency of H-ras mutations detected in this first large scale study using the highly sensitive and rapid PCR-based sequencing method was comparable to that reported by earlier studies with the nude mouse tumorigenesis variation of the 3T3 transfection assay. H-ras mutations can be early events in the development and progression of a significant proportion of human bladder cancer cases.