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Biomedical subjects

D Stott

Publications and source records attributed to D Stott.

At least 19 recordsLinked to original sources
PubMed2006

Pre-treatment haemoglobin levels and the prediction of response to neoadjuvant chemotherapy in breast cancer.

AIMS: A low pre-treatment haemoglobin level has been shown to negatively influence outcome in the treatment of tumours of the cervix, bladder and head and neck by radiotherapy. The purpose of this study was to assess the influence of baseline haemoglobin levels on the response to neoadjuvant chemotherapy for breast cancer. MATERIALS AND METHODS: One hundred and thirty-nine women receiving neoadjuvant chemotherapy for operable breast tumours (T2-4, N0-1, M0) were accessed from our prospective database. Women were treated between March 1999 and June 2004. The median age was 47 years (range 25-70). Most women were treated with 5-fluorouracil, epirubicin and cyclophosphamide chemotherapy (122/139 patients). Baseline haemoglobin levels were compared for clinical responders (partial or complete) and non-responders (stable or progressive disease) using Student's t test and logistic regression. The analysis was adjusted for nodal status, tumour size, tumour grade and menopausal status. RESULTS: The overall response rate was 84.9% (118/139), with a complete clinical response in 24.5% (34/139). Mean haemoglobin levels were 13.3 g/dl in responders and 13.4 g/dl in non-responders (range 7.9-15.8). The distributions of haemoglobin levels were not significantly different when comparing either responders with non-responders or 'good' responders with 'poor' responders (P = 0.70 and P = 0.32, respectively). If haemoglobin is treated as a binary variable using 12.0 g/dl as the threshold, there is a non-significant trend towards a reduction in the probability of achieving a good response if baseline haemoglobin is below 12.0 g/dl (odds ratio = 0.26, confidence interval = 0.06-1.21; P = 0.086). The rate of complete pathological response was 4.3% (6/139). The mean haemoglobin level in these patients was 14.2 g/dl (range = 12.8-15.7), but the small numbers precluded further analysis. CONCLUSIONS: There is no evidence for an influence of pre-treatment haemoglobin levels on the clinical response to neoadjuvant chemotherapy in breast cancer. It is unlikely that correction of anaemia above that which is warranted clinically will improve outcomes.

Adult↗
PubMed2006

Changes in eating behaviour following group therapy for women who binge eat: a pilot study.

Survey research is demonstrating that binge eating and compulsive eating may be a significant problem in the obese population. There is higher incidence of binge eating among women, associated with subjective distress and poor prognosis for weight control. Despite attendant health risks, researched clinical responses have not been developed. A before and after uncontrolled pilot study aimed to evaluate the effectiveness of group therapy for women who binge eat and compulsively eat. Participants attended a weekly integrative therapy group for 6 months. Measurements before and after the group intervention were taken using the Binge Eating Scale and Clinical Outcomes in Routine Evaluation inventories. Before and after interviews were thematically analysed for changes in eating behaviour. Following the group intervention, all participants demonstrated changes in eating behaviour measured by the Binge Eating Scale, the overall effect from baseline to 1 year demonstrates statistical significance. Qualitative data revealed four categories that underpinned reduction in binge eating: changes in dichotomous thinking, awareness of eating behaviour, detachment from food and dietary changes. An integrative model of group therapy warrants further research and refinement for this population, a group protocol for nurses working in the field of obesity and eating disorders could be developed.

Adult↗
PubMed2005

The reliability of lymph-node staging in rectal cancer after preoperative chemoradiotherapy.

AIMS: To determine the prognostic significance of the nodal stage and number of nodes recovered in the surgical specimen after preoperative synchronous chemoradiation (SCRT) and surgery for locally advanced or unresectable rectal cancer. MATERIALS AND METHODS: One hundred and eighty-two consecutive patients with locally advanced or unresectable (T3/T4) rectal carcinomas were entered on a prospective database and treated in this department with preoperative chemoradiation, followed 6-12 weeks later by surgical resection. Most patients received chemotherapy in the form of low-dose folinic acid and 5-fluorouracil (5-FU) 350 mg/m2 via a 60-min infusion on days 1-5 and 29-33 of a course of pelvic radiotherapy delivered at a dose of 45 Gy in 25 fractions over 33 days to a planned volume. After resection, patients with a positive circumferential margin (< or = 1 mm), extranodal deposits or Dukes' C histology received adjuvant 5-FU-based-chemotherapy (n = 40). RESULTS: After SCRT, 161 patients underwent resection. Twenty-one patients remained unresectable or refused an exenterative operation. Median follow-up is 36 months. Down-staging was achieved in most patients, with 19 having a complete pathological response (pT0). The median number of lymph nodes recovered for all patients was five (range 0-21). The 3-year survival rate for node-positive patients is 47%, for node-negative patients with less than three lymph nodes recovered is 62% and for node-negative patients with three or more lymph nodes recovered is 70%. Compared with node-positive patients, simple regression models revealed a reduced hazard ratio (HR) of 0.72 (0.36-1.43) for node-negative patients with less than three nodes recovered and 0.48 (0.26-0.89) for node-negative patients with three or more lymph nodes recovered. In a multivariate model, including nodal status, excision status, age and sex only positive excision margins significantly predicted a poor outcome: HR = 3.05 (1.55-5.97). CONCLUSIONS: The number of nodes found after preoperative chemoradiation is a significant prognostic factor by univariate analysis. In this study, patients with node-negative histology, and at least three nodes recovered, had better long-term survival than patients in whom two or less nodes were recovered or with positive nodes. This effect was attenuated by the inclusion of excision status in multivariate models.

Adenocarcinoma↗
PubMed2005

Dietary exposure to chemical migrants from food contact materials: a probabilistic approach.

A two-dimensional probabilistic model has been developed to estimate the short-term dietary exposure of UK consumers to migrants from food packaging materials. The current EU approach uses a default scenario of assuming that all individuals are 60 kg weight and consume 1 kg of food packaged in the material of interest per day. Using four UK National Dietary and Nutrition Surveys comprising 4-7 day dietary records for different age groups and survey years, a sample representative of the UK population has been obtained consuming around 4200 different food items. Each survey provides records for around 2000 individuals and supplies detailed information on the consumption of food and data on sex, height and socio-economic status which may be used to analyse the exposure of selected groups within the community. As a result we are able to address the variation in consumption of food amongst individuals, and account for actual body weights providing a more accurate representation of the 'true' exposure. The migrants bisphenol A diglycidyl ether (BADGE), di-2-ethylhexyl adipate (DEHA) and styrene were considered as specimen compounds although the methodology employed has the flexibility to adapt to other migrants and packaging types and indeed other food contaminants. Exposure for each individual is estimated by calculating and summing the individual exposure from each item in their diet, and is repeated for all individuals in each survey to produce a distribution of exposures for the population. The packaging type of each food item is assigned by utilizing known packaging types from the database or, by sampling from a distribution based upon market share information. The parameters contributing towards the exposure from a packaged dietary item are migrant concentration and item weight. Distributions are used to represent the inherent variation and uncertainty affecting these parameters. Where data on concentrations for a particular type of food are lacking, expert judgement is used to extrapolate from available data for other food types. The model can also be run using only migration data for food simulants. In this case, concentrations expected for each of the food items are assigned based on the data for the relevant food simulant. The primary outputs of the model are distributions of estimated daily intakes for the selected population. Each distribution gives the variation across the population subject to the uncertain parameters sampled in that iteration of the model. Analysing the ensemble of distributions allows us to obtain the confidence limits around estimates for percentiles due to the uncertainties. The probabilistic approach allows sensitivity analysis to evaluate the relative importance of the input parameters and places confidence bounds on the outputs to show the effect of the uncertainties and the contribution of each food type toward the overall exposure.

Adipates↗
PubMed2004

Perceptions of older people with cancer of information, decision making and treatment: a systematic review of selected literature.

BACKGROUND: Several studies have identified inadequacies in the care and treatment received by older patients with cancer, as opposed to their younger counterparts. These include over or under diagnosis, ineffective symptom management and lower survival rates in older people with cancer. Despite these inadequacies, there is a lack of evidence of older peoples' perspectives regarding their cancer diagnosis and treatment. MATERIALS AND METHODS: Studies for review were identified from systematic searches of literature published between January 1990 and November 2003, using PubMed, CINAHL and PsycINFO. Studies were selected for inclusion by using a number of criteria (i.e. date and language of publication, age of participants and thematic area). The aims of the review were to summarize and evaluate previous evidence on the views of older patients with cancer, regarding information, decision making and treatment. RESULTS: Eighteen studies of various methodologies met the criteria of the present review. In summary, older people with cancer are generally content with the information they receive, but not entirely satisfied with the quantity and quality of care and contact. They present with various needs, which are not always well met. Finally, they wish to be kept informed of their cancer diagnosis and treatment progress, but often do not wish to be told about progression of their illness and length of survival. CONCLUSIONS: Previous research has suffered a number of limitations regarding sampling procedures and methods of data collection. Other limitations included lack of consideration of the heterogeneity of older people with cancer and lack of a well-defined theoretical framework to guide design and data analysis. These may compromise not only rigour and the ability to generalize findings, but also the provision of patient-focused care. The difficulties of doing research in this area are also discussed and suggestions for future research are made.

Aged↗
PubMed2004

Challenges in conducting research with hospitalized older people with cancer: drawing from the experience of an ongoing interview-based project.

Older people with cancer often face the prospect of cognitive and physical frailty, increased vulnerability of psychological distress and limited access to resources. These factors present ethical and methodological challenges for conducting research in such patients, especially interviews in acute care settings. This paper discusses these challenges using experiences from an ongoing research project. The project is a patient-focused study on the perceptions of older people with cancer regarding information provided to them, decision making and treatment. Interviews with patients aged 65 or over with a cancer diagnosis are conducted in two clinical settings, care of the elderly wards and a cancer centre whilst they are in-patients. Patients' cognitive and physical status are assessed using clinical measures, whereas socio-demographic and medical data are obtained from patient files. Ethical challenges, including procedures to obtain valid consent, as well as methodological choices, including recruitment procedures and patient conditions are presented and debated with reference to previous literature. Suggestions for future research with older people with cancer are made based both on current experience and previous literature.

Aged↗
PubMed2002

Xbra3 elicits the production of neural tissue by a non-BMP-dependent mechanism in Xenopus sp.

Ectoderm cells in animal caps from Xenopus embryos develop to form either epidermis or neural tissue depending upon their receipt of intercellular signals. To date, several secreted neural inducers have been identified which act through the local inhibition of bone morphogenetic protein (BMP) signaling, preventing differentiation to epidermis and resulting in adoption of neural fate. In this work, we have exploited an interspecies animal cap assay, which enables detection of the effects of signaling molecules produced by cells of one animal cap and influencing development in a second cap cultured in close apposition in a Holtfreter combination. We show that expression of the T-box protein, Xbra3, in one cap causes the production of a factor, which causes adoption of neural fate by cells of the other animal cap. The action of this factor is not inhibited by the over-expression of BMP in cells of the responding animal cap, or by the inhibition of Wnt signaling. These findings suggest the existence of a secreted signaling molecule that is able to induce ectodermal cells to adopt neural fate by a mechanism independent of the inhibition of the BMP or Wnt signaling pathways.

Animals↗
PubMed2001

Identification and characterisation of a developmentally regulated mammalian gene that utilises -1 programmed ribosomal frameshifting.

Translational recoding of mRNA through a -1 ribosomal slippage mechanism has been observed in RNA viruses and retrotransposons of both eukaryotes and prokaryotes. Whilst this provides a potentially powerful mechanism of gene regulation, the utilization of -1 translational frameshifting in regulating mammalian gene expression has remained obscure. Here we report a mammalian gene, Edr, which provides the first example of -1 translational recoding in a eukaryotic cellular gene. In addition to bearing functional frameshift elements that mediate expression of distinct polypeptides, Edr bears both CCHC zinc-finger and putative aspartyl protease catalytic site retroviral-like motifs, indicative of a relic retroviral-like origin for Edr. These features, coupled with conservation of Edr as a single copy gene in mouse and man and striking spatio-temporal regulation of expression during embryogenesis, suggest that Edr plays a functionally important role in mammalian development.

Amino Acid Motifs↗
PubMed2000

Xbra3 induces mesoderm and neural tissue in Xenopus laevis.

Homologues of the murine Brachyury gene have been shown to be involved in mesoderm formation in several vertebrate species. In frogs, the Xenopus Brachyury homologue, Xbra, is required for normal formation of posterior mesoderm. We report the characterisation of a second Brachyury homologue from Xenopus, Xbra3, which has levels of identity with mouse Brachyury similar to those of Xbra. Xbra3 encodes a nuclear protein expressed in mesoderm in a temporal and spatial manner distinct from that observed for Xbra. Xbra3 expression is induced by mesoderm-inducing factors and overexpression of Xbra3 can induce mesoderm formation in animal caps. In contrast to Xbra, Xbra3 is also able to cause the formation of neural tissue in animal caps. Xbra3 overexpression induces both geminin and Xngnr-1, suggesting that Xbra3 can play a role in the earliest stages of neural induction. Xbra3 induces posterior nervous tissue by an FGF-dependent pathway; a complete switch to anterior neural tissue can be effected by the inhibition of FGF signalling. Neither noggin, chordin, follistatin, nor Xnr3 is induced by Xbra3 to an extent different from their induction by Xbra nor is BMP4 expression differentially affected.

Amino Acid Sequence↗
PubMed1999

Selective, covalent modification of beta-tubulin residue Cys-239 by T138067, an antitumor agent with in vivo efficacy against multidrug-resistant tumors.

Microtubules are linear polymers of alpha- and beta-tubulin heterodimers and are the major constituents of mitotic spindles, which are essential for the separation of chromosomes during mitosis. Here we describe a synthetic compound, 2-fluoro-1-methoxy-4-pentafluorophenylsulfonamidobenzene (T138067), which covalently and selectively modifies the beta1, beta2, and beta4 isotypes of beta-tubulin at a conserved cysteine residue, thereby disrupting microtubule polymerization. Cells exposed to T138067 become altered in shape, indicating a collapse of the cytoskeleton, and show an increase in chromosomal ploidy. Subsequently, these cells undergo apoptosis. Furthermore, T138067 exhibits cytotoxicity against tumor cell lines that exhibit substantial resistance to vinblastine, paclitaxel, doxorubicin, and actinomycin D. T138067 is also equally efficacious in inhibiting the growth of sensitive and multidrug-resistant human tumor xenografts in athymic nude mice. These observations suggest that T138067 may be clinically useful for the treatment of multidrug-resistant tumors.

Animals↗
PubMed1997

Xsox17alpha and -beta mediate endoderm formation in Xenopus.

We have isolated two Xenopus relatives of murine Sox17 expressed in gastrula presumptive endoderm. Xsox17alpha and -beta expression can be induced in animal caps by activin, but not by FGF. Ectopic expression of these genes in animal caps induces the expression of endoderm markers; this induction is blocked by overexpression of a fusion of the Xsox17beta HMG domain to the Drosophila Engrailed repressor domain, as is induction of endoderm markers by activin and the expression of endodermal markers in whole embryos and isolated vegetal poles. These experiments, as well as the effects of the mRNAs on embryo phenotypes, suggest that the Xsox17 genes mediate an activin-induced endoderm differentiation pathway in animal caps and are involved in normal endoderm differentiation in embryos.

Activins↗
PubMed1997

T promoter activity in the absence of functional T protein during axis formation and elongation in the mouse.

The T (Brachyury) gene, which encodes a transcription factor, is involved in the formation of posterior mesoderm. Although studies in Xenopus have shown that T gene expression is responsive to mesoderm inducing factors and furthermore suggest the existence of an autoregulatory loop involving T itself, eFGF, and the FGF receptor, little is known about the regulation of T expression in the mouse. We report here that in the mouse the expression of fgf-4, the putative homologue of Xenopus efgf, is not dependent on the presence of T protein during the first 48 hr of gastrulation. Furthermore, we address the question of autoregulation using a chimeric approach. Introduction of a T promoter-lacZ construct into T/T ES cells results in T promoter activity in the primitive streak and tail bud in the absence of functional T protein. Therefore, we suggest that a direct FGF and T autoregulatory loop is unlikely to operate during gastrulation and axis elongation in the mouse.

Animals↗
PubMed1996

Distinct regulatory control of the Brachyury gene in axial and non-axial mesoderm suggests separation of mesoderm lineages early in mouse gastrulation.

Brachyury is required for the normal extension of the anteroposterior axis during mouse embryogenesis. A transgene comprising sequences from -500 to +150 relative to the start of Brachyury transcription, and the reporter gene lacZ, recapitulates some, but not all elements of Brachyury expression. Beta-Galactosidase expression is seen in the primitive streak from 6.5 d.p.c. but there is no detectable reporter expression in the node or notochord. Thus, the regulatory sequences required for the expression of Brachyury in the cells traversing the primitive streak are distinct from those required for the initiation of expression in the node. This suggests that different or additional signals are involved in activation of Brachyury in the node and notochord than those inducing Brachyury in the primitive streak. Additionally, the data suggest the possibility that axial and non-axial mesoderm are distinct from the earliest stages of Brachyury expression.

Animals↗
PubMed1996

Genetic mapping of the human homologue (T) of mouse T(Brachyury) and a search for allele association between human T and spina bifida.

We describe a genetic analysis of the human homologue (T) of the mouse T (Brachyury) gene; human T was recently cloned in our laboratory. The protein product of the T gene is a transcription factor crucial in vertebrates for the formation of normal mesoderm. T mutant Brachyury mice die in midgestation with severe defects in posterior mesodermal tissues; heterozygous mice are viable but have posterior axial malformations. In addition to its importance in development, T has intrigued geneticists because of its association with the mouse t-haplotype; this haplotype is a variant form of the t-complex and is characterized by transmission ratio distortion, male sterility and recombination suppression. We have identified a common polymorphism of human T by single strand conformation polymorphism (SSCP) and used this in mapping studies and to re-investigate the idea that human T is involved in susceptibility to the multifactorial, neural tube defect, spina bifida. Our mapping data show that human T maps to 6q27 and lies between two other genes of the t-complex, TCP1 and TCP10. These data add to the evidence that in man the genes of the t-complex are split into two main locations on the short and long arms of chromosome 6. We have used an allele association test which is independent of mode of inheritance and penetrance to analyse data from the spina bifida families. Using this test we find evidence for a significant (p = 0.02) association between transmission of the TIVS7-2 allele of the human T gene and spina bifida.

Alleles↗