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D Ellison

Publications and source records attributed to D Ellison.

At least 19 recordsLinked to original sources
PubMed2002

Comparison of capillary electrophoresis and reversed-phase liquid chromatography for determination of the enantiomeric purity of an M3 antagonist.

The chiral separation of an M3 antagonist was investigated using capillary electrophoresis (CE) with various sulfated cyclodextrins and by reversed-phase liquid chromatography with derivatized cellulose, derivatized amylose, and two protein stationary phases. Operational parameters for each technique, such as the concentration of the chiral selectors, background electrolyte (or mobile phase) pH and type, organic modifiers, injection mode and temperature were varied in order to achieve a desired elution order and to meet a 0.1% limit of quantitation (LOQ) criteria. Based on the advantages and disadvantages of each technique, a practical CE method using sulfated gamma-cyclodextrin was selected. The method was validated in terms of linearity, LOQ, accuracy, ruggedness and precision.

Buffers↗
PubMed2002

Axillary node status in breast cancer patients prior to surgery by imaging with Tc-99m humanised anti-PEM monoclonal antibody, hHMFG1.

In early breast cancer axillary nodes are usually impalpable and over 50% of such patients may have an axillary clearance when no nodes are involved. This work identifies axillary node status by imaging with a Tc-99m radiolabelled anti-Polymorphic Epithelial Mucin, humanised monoclonal antibody (human milk fat globule 1), prior to surgery in 30 patients. Change detection analysis of image data with probability mapping is undertaken. A specificity of 93% and positive predictive value of 92% (both 100% if a second cancer in the axilla with negative nodes is considered) were found. A strategy for combining negative imaging with the sentinel node procedure is presented.

Adult↗
PubMed2002

Classifying the medulloblastoma: insights from morphology and molecular genetics.

Significant advances in the treatment of the medulloblastoma (MB) have been made in the last 30 years, reducing mortality by 2-fold. Further improvements in the cure rate require an increased understanding of the biology of MBs, and this will translate into refinements in their classification. Scrutiny of the cytological variation found among MBs has recently led to the concept of the anaplastic MB, which overlaps the large-cell variant and appears to share its poor prognosis. In contrast, the MB with extensive nodularity, a distinctive nodular/desmoplastic variant occurring in infants, has a better outcome than most MBs in these young patients. Building on cytogenetic studies that have drawn attention to abnormalities on chromosome 17 in over a third of MBs, research shows non-random losses on chromosomes 8, 9, 10, 11 and 16, and gains on chromosomes 1, 7 and 9. Overexpression of ErbB2 receptors and losses on chromosome 17p have been proposed as independent indicators of aggressive behaviour, while high TrkC receptor expression indicates a favourable outcome. There is a strong association between anaplastic/large-cell tumours and MYC amplification, which has previously been linked with aggressive disease, but associations between abnormalities on chromosome 17 and anaplastic/large-cell MBs and between abnormalities in the shh/PTCH pathway and the desmoplastic variant are more controversial. Classification of the MB histopathologically and according to profiles of molecular abnormalities will help both to rationalize approaches to therapy, increasing the cure rate and reducing long-term side-effects, and to suggest novel treatments.

Cerebellar Neoplasms↗
PubMed2001

Clinical and molecular stratification of disease risk in medulloblastoma.

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 expression' (P = 0.003) and 'isolated 17p loss' (P = 0.003). Combined analysis of clinical and molecular factors enabled greater resolution of disease risk than clinical factors alone, identifying a sub-population of patients with particularly favourable disease outcome. These data support the hypothesis that a combination of clinical and molecular factors may afford a more reliable means of assigning disease risk in patients with medulloblastoma, thereby providing a more accurate basis for targeting therapy in children with this disease.

Adolescent↗
PubMed2001

Novel ERBB4 juxtamembrane splice variants are frequently expressed in childhood medulloblastoma.

We recently reported a significant relationship between tumor cell expression of the ERBB4 receptor, the most recently described member of the epidermal growth factor receptor family, and aggressive tumor phenotype in childhood medulloblastoma. Two alternative juxtamembrane (JM) isoforms of the ERBB4 receptor have been described. Termed JMa and JMb, these variants possess different receptor processing and ligand-binding characteristics. In the current study, we employed an RT-PCR and sequencing strategy to determine the pattern of ERBB4 JM isoform expression in a large (n = 78) series of pediatric medulloblastomas. JMa and JMb transcript expression was detected in 53% and 28% of tumor samples, respectively. In addition, two novel ERBB4 JM isoforms, which we have termed JMc and JMd, were isolated from 10% and 36% of tumors, respectively. Sequence analysis revealed the JMc transcript to contain a deletion of the entire JM region. In contrast, JMd includes an extended coding region, retaining both the JMa and JMb sequences. Neither of these novel isoforms was detected in normal human adult cerebellum, but expression of JMd was observed in developing fetal cerebellum, suggesting that this later isoform may represent an ERBB4 transcript restricted to primitive neuroectoderm-derived tissue. To confirm that the four ERBB4 JM isoforms arise by alternative RNA splicing, we sequenced the intron-exon junctions of the human ERBB4 gene within the JM region. This demonstrated the four ERBB4 JM variants to be encoded by two short exons containing the JMb and JMa sequences positioned in the order 5' to 3' and separated by a 121 bp intron.

Alternative Splicing↗
PubMed2001

Absence of mutations in the growth hormone (GH)-releasing hormone receptor gene in GH-secreting pituitary adenomas.

OBJECTIVE: GH-releasing hormone (GHRH) is a potent stimulator of somatotroph cell proliferation and GH secretion. GHRH acts via binding to a G-protein coupled receptor (GPCR) (GHRH-R), that activates adenylyl cyclase (AC) and increases growth and function of somatotroph cells. Indeed, a subset (30--40%) of somatotrophic adenomas contain somatic mutations of the GNAS1 gene that encodes the alpha subunit of the G-protein (G(s)alpha) that stimulates AC. As activating mutations of other GPCRs cause development of endocrine tumours, we hypothesized that somatic activating mutations of the GHRH-R might provide the molecular basis for somatotroph cell proliferation in a subset of human GH-secreting pituitary adenomas. DESIGN: We analysed genomic DNA isolated from 26 somatotrophinomas, 17 of which lacked activating mutations in the GNAS1 gene. We individually amplified via polymerase chain reaction all 13 coding exons and the exon-intron boundaries of the GHRH-R gene. We used denaturing gradient gel electrophoresis to search for abnormalities in exons 1 through 11. Abnormally migrating bands were subjected to direct sequencing. Exons 12 and 13, encoding for the intracellular C-terminal domain, were subjected to direct sequencing. RESULTS: Mutations were not detected in any of the tumours, but a rare polymorphism in codon 225 corresponding to the third transmembrane domain (V225I) was discovered. CONCLUSIONS: GHRH-R mutations are absent or rare in somatotrophinomas, and other mechanisms must explain the somatotroph cell proliferation in the adenomas that lack activating mutations in the GNAS1 gene.

Adenoma↗
PubMed2001

Anti-Yo antibody-positive cerebellar degeneration associated with endometrial carcinoma: case report and review of the literature.

Paraneoplastic cerebellar degeneration (PCD) is a rare, severely debilitating disease, often with a rapid onset and progression, which predate the diagnosis of malignancy. Despite characteristic features, diagnosis is commonly difficult and successful therapy, which relies on early instigation of treatment, is rare. Here we present a patient in whom anti-Yo antibody-positive PCD was associated with endometrial carcinoma and an extensive review of the literature outlining the clinical features, pathogenesis and treatment of PCD.

Aged↗
PubMed2001

Localization of thiazide-sensitive Na(+)-Cl(-) cotransport and associated gene products in mouse DCT.

The mammalian distal nephron develops a complex assembly of specialized cell types to accomplish the fine adjustment of urinary electrolyte composition. The epithelia of the distal convoluted tubule (DCT), the connecting tubule (CNT), and the cortical collecting duct (CCD) show an axial structural heterogeneity that has been functionally elucidated by the localization of proteins involved in transepithelial ion transport. We compared the distribution of the thiazide-sensitive Na(+)-Cl(-) cotransporter (TSC), basolateral Na(+)/Ca(2+) exchanger (Na/Ca), cytosolic calcium-binding proteins calbindin D(28K) and parvalbumin, and the key enzyme for selective aldosterone actions, 11 beta-hydroxysteroid-dehydrogenase 2 (11HSD2), in the distal convolutions of the mouse. In the mouse, as opposed to the rat, we found no clear subsegmentation of the DCT into a proximal (DCT1) and a distal (DCT2) portion. The TSC was expressed along the entire DCT. Na/Ca and calbindin D(28K) were similarly expressed along most of the DCT, with minor exceptions in the initial portion of the DCT. Both were also present in the CNT. Parvalbumin was found in the entire DCT, with an occasional absence from short end portions of the DCT, and was not present in CNT. 11HSD2 was predominantly located in the CNT and CCD. Short end portions of DCT only occasionally showed the 11HSD2 signal. We also observed an overlap of 11HSD2 immunoreactivity and mRNA staining. Our observations will have implications in understanding the physiological effects of gene disruption and targeting experiments in the mouse.

11-beta-Hydroxysteroid Dehydrogenase Type 2↗
PubMed2001

February 2001: A 74 year old man with a history over 3 months of increasing dyspnea and malaise.

The February COM: A man of 78 years with idiopathic late-onset cerebellar ataxia developed renal failure in association with a high ESR and positive pANCA. This was complicated by a subclinical spinal subarachnoid hemorrhage which was related to necrotizing inflammation of small leptomeningeal vessels. Renal cortical infarcts were due to similar inflammation in arcuate and interlobular arteries. Spinal subarachnoid hemorrhage is rare and usually due to rupture of an arteriovenous malformation. However, an immunogenic connective tissue disorder should be considered in the differential diagnosis. In this case, the histology and results of an autoantibody screen support a diagnosis of microscopic polyangiitis.

Acute Kidney Injury↗
PubMed2000

Imaging with prostate-specific membrane antigen (PSMA) in prostate cancer.

Radioimmunoscintigraphy using a radio-labelled antibody to prostate-specific membrane antigen (PSMA) has growing applications as a means of tissue-specific imaging based on functional characteristics and complements traditional staging investigations. Clinical applications in men with carcinoma of the prostate are being refined, and this study reports outcomes with this technique in our practice. Prostatic immunoscintigraphy scans were performed with In-111 CYT 356 in 49 men with carcinoma of the prostate, obtaining sequential images in two and three dimensions at 10 min, 24 and 48 h. Of the 49 men, 36 had clinically localized cancer, 10 had recurrent disease after radical radiotherapy or radical prostatectomy and three had rising PSA after primary endocrine treatment. Scan findings are discussed in the context of clinical management. Of the 36 men with clinically localized cancer, seven had increased uptake in regional and distant lymph nodes. Of these seven, three were treated with hormone manipulation, two by radical prostatectomy and two by radical radiotherapy. Among 10 patients who had recurrence after radical treatment of the primary tumour, scans showed local recurrence alone in four, and six had regional or distant metastases. Three patients treated with primary hormone manipulation had scans for rising PSA, and of these one had a positive regional node and two had distant soft tissue and bone metastases. In conclusion, prostatic radio-immunoscintigraphy scans highlight tissues involved by prostate cancer, including the prostate, lymph nodes, soft tissues and bone metastases as well as pelvic recurrence. Results may contribute to the clinical management of individual patients, although histological confirmation may be appropriate when considering alternative treatment. Prostate Cancer and Prostatic Diseases (2000) 3, 47-52

Journal Article↗
PubMed2000

A new case of frontotemporal dementia and parkinsonism resulting from an intron 10 +3-splice site mutation in the tau gene: clinical and pathological features.

Hereditary frontotemporal dementia and parkinsonism (FTDP) linked to chromosome 17 (FTDP-17) constitutes a new form of tauopathy, and mutations in the tau gene have recently been reported in some affected families. This report presents clinical and neuropathological data from a member of a British family (SOT 254) with a history of dementia and movement disorder. The medical history of the affected patient, a woman aged 44 years, was reviewed, and a detailed post-mortem examination of the brain was undertaken. A panel of well characterized phosphorylation-dependent and independent anti-tau antibodies was used to assess tau pathology, and inclusions were examined by electron microscopy. Neuronal loss and gliosis were widely distributed, but most severe in neocortical regions, and were associated with abundant neuronal and glial tau inclusions which consisted of a mixture of paired helical filaments (PHFs), similar to those in Alzheimer's disease, and distinct twisted ribbon-like filaments. Genomic DNA was obtained from post-mortem tissue from the index patient, and blood from two unaffected members of the same family. For the index case only, sequencing of intronic sequences flanking exon 10 of the tau gene identified a G to A transition at position +3 of the splice-donor site downstream of exon 10, identical to that reported in multiple system tauopathy with presenile dementia (MSTD). The clinical, neuropathological and genetic findings strongly suggest that SOT 254 represents a new example of FTDP-17 resulting from a mutation in the tau gene. These results are compared with those reported for other FTDP-17 families, i.e. for MSTD.

Adult↗
PubMed2000

Imbalances of chromosome 17 in medulloblastomas determined by comparative genomic hybridisation and fluorescence in situ hybridisation.

AIMS: To investigate the status of chromosome 17 in a series of medulloblastomas using comparative genomic hybridisation (CGH) and fluorescence in situ hybridisation (FISH). METHODS: Frozen tissue and formalin fixed, paraffin was embedded tissue from 27 medulloblastomas were analysed by CGH and FISH, respectively. CGH ratio profiles for chromosome 17 were compared with the results of FISH, for which loss or gain of 17p or 17q was assessed in two distinct ways using a combination of differentially labelled subtelomeric and centromeric probes and analysing 200 nuclei in each tumour. RESULTS: CGH revealed imbalances consistent with isochromosome 17q in eight of 27 tumours. Either loss of 17p or gain of 17q was identified in a further nine tumours, whereas 10 tumours were apparently balanced. Using control results from preparations of paraffin wax embedded tonsils, thresholds for the detection of abnormalities by FISH were established, either by determining the dominant pattern of signals in each case, or the mean ratio of subtelomeric to centromeric signals. Results by CGH and FISH were concordant in 21 of 27 tumours. In the remainder, most discrepancies related to methodological differences. CONCLUSIONS: CGH has a role in disclosing common, genome wide chromosomal gains or losses in tumours, the clinical relevance of which can then be studied in large archival series of paraffin wax embedded tumours using FISH.

Adolescent↗
PubMed2000

A longitudinal study of siblings of children with chronic disabilities.

OBJECTIVE: To examine the unaffected siblings of 2 different groups with chronic disabilities, pervasive developmental disorder (PDD) and Down syndrome (DS), over 3 years, comparing their adjustment with each other and with the siblings of a nondisabled group. METHOD: This study examines 137 siblings of children with PDD, children with DS, and developmentally normal children (control group) initially and 127 siblings at follow-up 3 years later. Their adjustment is measured by the Survey Diagnostic Instrument (SDI), completed by caregivers and teachers. Predictor variables include sibling self-perception, social support, and relationship with sibling, as indicated by siblings; caregiver psychosocial factors such as parental stress, caregiver depression, and marital relationship; family systems characteristics as viewed by both caregiver and sibling; and difficulty that disabled child causes as perceived by the primary caregiver. RESULTS: Significantly more adjustment problems are found in the siblings of PDD children at both times when compared with siblings of DS and control children. Caregivers of PDD children report the highest levels of distress and depression, and this persists over time. Parent distress was found, at both times, to be related to sibling adjustment problems, regardless of study group. CONCLUSION: These results have implications for preventive intervention for the unaffected siblings of PDD children.

Adaptation, Psychological↗
PubMed2000

Photoreduction of monoclonal antibodies for conjugation and fragmentation.

The conjugation of enzymes, fluorescent or radioactive labels, cross-linkers and other moieties to antibodies is a commonly performed procedure in biochemical research. Using reduced disulphides, conjugation can be an inconvenient, multistep, time- and material-consuming process. We have developed a reduction technique based on UV irradiation, which lacks these drawbacks. Antibodies are irradiated in a sealed vial for a few minutes by a common laboratory UV source in the presence of stannous ions, following the depletion of atmospheric oxygen. The preparation may subsequently be conjugated with thiol-reactive probes such as maleimide derivatives, with no need for any prior purification or concentration. This simple, rapid and effective reduction and conjugation process results in a fully functional immunoglobulin conjugate that can be used for a variety of biochemical applications.

Animals↗
PubMed1998

99mTc-labelled SM3 in the preoperative evaluation of axillary lymph nodes and primary breast cancer with change detection statistical processing as an aid to tumour detection.

The extent of primary surgery for breast cancer could be tailored to the patient if previous information on the presence or absence of lymph node involvement could be reliably determined. Prospective radioimmunoscintigraphy in 29 patients with primary breast cancer that was found on screening has been undertaken with 555 MBq (15 mCi) 99mTc SM3, an Imperial Cancer Research Fund (ICRF) murine monoclonal antibody, 0.5 mg with images at 10 min and 22 h, and analysis using a change detection algorithm. Sites of significant change between the early and later images were displayed as a map of probabilities. Image-positive and -negative axillary lymph nodes were compared by histology in the 28 evaluable patients. The correct identification of the presence or absence of node involvement, even if impalpable, has been shown in 24 out of 28 patients (29 lymph node groups). Sensitivity was 90% (nine out of ten), specificity 84% (16 out of 19) and accuracy 86%. These results encourage further assessment of this technique.

Adult↗
PubMed1998

Ki-67 immunolabelling index is a prognostic indicator in childhood posterior fossa ependymomas.

Conventional histological evaluation and subclassification of childhood ependymomas poorly predict their biological behaviour. The Ki-67 labelling index (Ki-67 LI), a measure of growth fraction, correlates with the biological behaviour of several neoplasms, and this retrospective study tested the hypothesis that Ki-67 LI is a prognostic indicator in childhood posterior fossa ependymomas. Immunocytochemistry using an antibody to Ki-67 was undertaken on 5 microns sections of formalin-fixed, paraffin-embedded tissue from 74 cases of childhood (age < 16 years.) posterior fossa ependymoma. A Ki-67 LI was established by counting the proportion of labelled nuclei in more than 1000 cells from several histological fields. Several clinical and histological variables (including Ki-67 LI) potentially associated with survival were entered into univariate and multivariate analyses using a Cox proportional hazards model. Variables that showed a significant and independent association with survival were Ki-67 LI (P < 0.002), whether total surgical resection had been achieved according to operation records (P < 0.03), and whether no adjuvant therapy had been given (P < 0.01). Age, sex, and the presence of necrosis or microvascular proliferation did not correlate with survival. In our defined population of patients with ependymomas, Ki-67 LI is a strong prognostic indicator. We recommend that Ki-67 LI is used in the histological evaluation of childhood posterior fossa ependymomas during trials of novel adjunctive therapies.

Adolescent↗
PubMed1998

Effect of sibling perception of differential parental treatment in sibling dyads with one disabled child.

OBJECTIVE: To examine sibling perception of parental differential treatment in families of children with pervasive developmental disorder (PDD), Down syndrome (DS), and nondisabled controls. METHOD: Sibling self-concept and social support were studied in the context of sibling perceptions of parental differential treatment and caretaker plus teacher evaluations of sibling behavioral adjustment. Measures were completed at time 1 and time 2. The effect of parental stress and the difficulty of the disabled child, as well as the sibling relationship, were considered. RESULTS: For siblings of PDD children, internalizing and externalizing behavior problems identified by caretakers were evident at time 1 and more accentuated at time 2, at which time teachers also identified these difficulties. DS siblings were reported by caretakers and teachers to have only internalizing problems and only at time 2. These difficulties related to the perception for PDD siblings that they were preferred over their disabled sibling and for the DS sibling that their disabled sibling was preferred. Feelings of low competence predicted internalizing difficulties. Social support, especially over time, had a positive effect for all siblings, including the controls. CONCLUSION: The elucidation of specific mechanisms contributing to adjustment problems in the siblings of disabled children will allow for the development of specific preventive interventions.

Adolescent↗