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Khalifa N, Talbot E, Schneider J, Walker DM, Bates P, Bird Y, Davies D, Brookes C, Hall J, Völlm B. Individual placement and support (IPS) for patients with offending histories: the IPSOH feasibility cluster randomised trial protocol. BMJ Open 2016; 6:e012710. [PMID: 27449894 PMCID: PMC4964185 DOI: 10.1136/bmjopen-2016-012710] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
INTRODUCTION People with involvement in forensic psychiatric services face many obstacles to employment, arising from their offending, as well as their mental health problems. This study aims to assess the feasibility of conducting a randomised controlled trial (RCT) to evaluate the effectiveness of individual placement and support (IPS), in improving employment rates and associated psychosocial outcomes in forensic psychiatric populations. IPS has been found consistently to achieve employment rates above 50% in psychiatric patients without a history of involvement in criminal justice services. METHODS/DESIGN This is a single-centre feasibility cluster RCT. Clusters will be defined according to clinical services in the community forensic services of Nottinghamshire Healthcare NHS Foundation Trust (NHCT). IPS will be implemented into 2 of the randomly assigned intervention clusters in the community forensic services of NHCT. A feasibility cluster RCT will estimate the parameters required to design a full RCT. The primary outcome is the proportion of people in open employment at 12-month follow-up. Secondary outcome measures will include employment, educational activities, psychosocial and economic outcomes, as well as reoffending rates. Outcome measures will be recorded at baseline, 6 months and 12 months. In accordance with the UK Medical Research Council guidelines on the evaluation of complex interventions, a process evaluation will be carried out; qualitative interviews with patients and staff will explore general views of IPS as well as barriers and facilitators to implementation. Fidelity reviews will assess the extent to which the services follow the principles of IPS prior, during and at the end of the trial. ETHICS AND DISSEMINATION Ethical approval was obtained from the East Midlands Research Ethics Committee-Nottingham 1 (REC reference number 15/EM/0253). Final and interim reports will be prepared for project funders, the study sponsor and clinical research network. Findings will be disseminated through peer-reviewed journals, conferences and event presentations. TRIAL REGISTRATION NUMBER NCT02442193; Pre-results.
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Walker DM, Dowthwaite S, Cronin D, Molden-Hauer T, McMonagle B. Metastatic pilomatrix carcinoma: Not so rare after all? A case report and review of the literature. EAR, NOSE & THROAT JOURNAL 2016; 95:117-120. [PMID: 26991221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023] Open
Abstract
Pilomatrixoma is a slowly growing benign tumor of the dermal hair cells. Metastatic disease is exceptionally rare. Pilomatrixoma can occur at any age, but most patients are older than 40 years at presentation. Approximately 60% of these lesions occur in the head and neck region. Their size is usually about 4 cm at the time of presentation. Surgical excision with adequate margins is still the preferred treatment. We report a case of an aggressive malignant metastatic pilomatrixoma in a 43-year-old woman who underwent multiple extensive local resections. However, she died within 4 months of presentation.
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Walker DM, Robbins JM, Brown D, Berhane Z. Improving processes of care for overweight and obese children: evidence from the 215-GO! program in Philadelphia health centers. Public Health Rep 2014; 129:303-10. [PMID: 24791028 DOI: 10.1177/003335491412900314] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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Walker DM, Hii MW, Skinner CE, Hopkins GH. Roux-en-Y gastric bypass after successful weight loss with a laparoscopic adjustable gastric band: rationales and early outcomes in patients of body mass index<35 kg/m(2.). Surg Obes Relat Dis 2014; 10:1104-8. [PMID: 24986461 DOI: 10.1016/j.soard.2014.03.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Revised: 03/05/2014] [Accepted: 03/08/2014] [Indexed: 02/01/2023]
Abstract
BACKGROUND Laparoscopic adjustable gastric banding (LAGB) has a number of well-established acute and chronic issues that can require revisional surgical procedures. There is no existing data to evaluate conversion of band patients with body mass index (BMI)<35 kg/m(2) from LAGB to a Roux-en-Y gastric bypass (RYGB). This study aims to report on the indications for and the safety profile of conversion of the LAGB to RYGB in patients with BMI<35 kg/m(2). METHODS A review of data from 200 consecutive conversions of LAGB to RYGB was conducted. Fifty-two patients whose BMI was<35 kg/m(2) were included in this analysis. Indications for conversion, technical details, early morbidity, length of hospital stay, and weight loss data were assessed. RESULTS Laparoscopic conversion to RYGB was performed in 100% of patients. The median BMI pre-RYGB was 32.8 kg/m(2). The most common indication for surgery was weight regain after removal of LAGB (28.8%). There was no mortality. Early morbidity was seen in 25% of patients; the most common complication was stricture of the gastrojejunal anastomosis (9 patients). CONCLUSION Morbidity resulting from conversion of LAGB to RYGB in patients with BMI <35 kg/m(2) is similar to that seen in the BMI>35 kg/m(2) population. The procedure is technically challenging and morbidity rates are higher than those reported for surgically 'naïve' patients. It is recommended that this procedure be undertaken by appropriately trained surgeons in high-volume bariatric centers to optimize safety and outcomes.
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West NEJ, Walker DM, Ray SG, Weston C, Quinn T, Birkhead JS. 021 IS THERE A NEED FOR SPECIALIST CARDIAC CARE FOR PATIENTS WITH NON-ST ELEVATION MYOCARDIAL INFARCTION? AN ANALYSIS OF 85 780 PATIENT EPISODES FROM THE MINAP DATABASE 2008–2009:. BRITISH HEART JOURNAL 2013. [DOI: 10.1136/heartjnl-2013-304019.21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Chung TTLL, Drake WM, Plowman PN, Metcalfe K, Grossman AB, Akker SA, Chew SL, Besser GM, Walker DM, Koltowska-Haggstrom M, Wilton P, Mattsson AF, Monson JP. No clear evidence for an association between GH replacement and relapse of intracranial germ cell tumours: single centre and KIMS experience. Eur J Endocrinol 2010; 163:357-8. [PMID: 20516207 DOI: 10.1530/eje-10-0498] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Moyes VJ, Walker DM, Owusu-Antwi S, Maher KT, Metherell L, Akker SA, Monson JP, Clark AJL, Drake WM. d3-GHR genotype does not explain heterogeneity in GH responsiveness in hypopituitary adults. Clin Endocrinol (Oxf) 2010; 72:807-13. [PMID: 20039885 DOI: 10.1111/j.1365-2265.2009.03768.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Heterogeneity in growth hormone (GH) responsiveness in adult hypopituitary patients receiving recombinant human GH (rhGH) is poorly understood; doses vary up to fourfold between individuals. Deletion of exon 3 in the GH receptor (d3-GHR) has been linked to enhanced rhGH responsiveness in children. We investigated the role of the d3-GHR polymorphism in determining adult rhGH responsiveness. METHODS One hundred and ninety-four patients treated with an identical rhGH dosing protocol in a single centre were genotyped for the d3-GHR, and the results correlated with changes in serum IGF-I and clinical parameters of GH responsiveness after 6 and 12 months of GH replacement therapy. RESULTS Allele frequencies for homozygous full length (fl/fl), heterozygous d3 (fl/d3) and homozygous d3 (d3/d3) were 52%, 38.7% and 9.3%, respectively, and were in Hardy-Weinberg equilibrium. Baseline IGF-I and DeltaIGF-I at 6 months were comparable between groups. DeltaIGF-I at 12 months was significantly greater in the d3/d3 group (P = 0.028). No difference was detected between fl/d3 and fl/fl groups. Regression analyses of DeltaIGF-I at 12 months and DeltaIGF-I/rhGH dose confirmed a significant relationship of d3/d3 genotype on rhGH response. There was no difference between groups in maintenance rhGH dose between genotypes. CONCLUSION Homozygosity for d3-GHR confers a marginal increase in GH responsiveness at 12 months but without a detectable change in maintenance rhGH dose required. Both d3 alleles are required to achieve this response; given that only 10% of the population are d3 homozygotes, the d3GHR does not explain the marked heterogeneity of GH responsiveness in hypopituitary adults.
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Mehta PA, Dubrey SW, McIntyre HF, Walker DM, Hardman SMC, Sutton GC, McDonagh TA, Cowie MR. Improving survival in the 6 months after diagnosis of heart failure in the past decade: population-based data from the UK. Heart 2009; 95:1851-6. [PMID: 19587390 DOI: 10.1136/hrt.2008.156034] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
OBJECTIVE To investigate the secular trend in survival after a new diagnosis of heart failure in the UK population. DESIGN AND SETTING Comparison of all-cause mortality in the 6 months after diagnosis of heart failure in population-based studies in the south east of England in 2004-5 (Hillingdon-Hastings Study) and 1995-7 (Hillingdon-Bromley Studies). PARTICIPANTS 396 patients in the 2004-5 cohort and 552 patients in the 1995-7 cohort with incident (new) heart failure. MAIN OUTCOME MEASURES All-cause mortality. RESULTS All-cause mortality rates were 6% (95% CI 3% to 8%) at 1 month, 11% (8% to 14%) at 3 months and 14% (11% to 18%) at 6 months in the 2004-5 cohort compared with 16% (13% to 20%), 22% (19% to 25%) and 26% (22% to 29%), respectively, in the 1995-7 cohort (difference between the two cohorts, p<0.001). The difference in survival was not explained by any difference in the demographics or severity of heart failure at presentation. There was a difference at baseline and thereafter in the use of neurohormonal antagonists (beta-blockers and angiotensin-converting enzyme inhibitors). CONCLUSIONS Although early mortality remains high among patients with newly diagnosed heart failure in the UK general population, there is strong evidence of a marked improvement in survival from 1995-7 to 2004-5, perhaps partly explained by an increased usage of neurohormonal antagonists.
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Eamens GJ, Walker DM, Porter NS, Fell SA. Radiometric pooled faecal culture for the detection ofMycobacterium aviumsubspparatuberculosisin low-shedder cattle. Aust Vet J 2008; 86:259-65. [DOI: 10.1111/j.1751-0813.2008.00313.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Eamens GJ, Walker DM, Porter NS, Fell SA. Pooled faecal culture for the detection of Mycobacterium avium subsp paratuberculosis in goats. Aust Vet J 2007; 85:243-51. [PMID: 17547638 DOI: 10.1111/j.1751-0813.2007.00160.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
OBJECTIVE To evaluate pooled faecal culture for herd diagnosis of caprine Johne's disease and relate these findings to faecal shedding rates of Mycobacterium avium subsp paratuberculosis (Map). DESIGN Radiometric broth culture was applied to several pooling dilutions, and shedding rates were estimated from a regression equation based on bacterial growth rates and known processing losses during radiometric culture. PROCEDURE Sixteen faecal samples from goats naturally infected with sheep (n = 3) or cattle (n = 13) strains of Map, were diluted in normal goat faeces from 1 in 5 to 1 in 50. Cultures were confirmed by IS900 polymerase chain reaction and restriction endonuclease analysis, and mycobactin dependency. The numbers of viable Map in the culture inocula were determined by endpoint titration (most probable number) of nine samples and related to a cumulative growth index. RESULTS A pooling dilution of 1 in 25 with an incubation period of 10 weeks detected 13 of 16 culture positive goats, all shedding > or = 2 x 10(4) Map per gram of faeces. Two samples containing very low numbers of Map (< 2 x 10(3)/g) were only culture positive from undiluted faeces. Thirteen of 16 goats were considered to be shedding low to moderate concentrations of Map (< 2 x 10(5)/g faeces). CONCLUSIONS These data support a pooling dilution of 1 in 25 for application of pooled faecal culture as a diagnostic tool in caprine Johne's disease control. A test based on this dilution would reduce laboratory costs of whole herd testing in goats by approximately 40% relative to serology and 75 to 90% relative to individual faecal culture.
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Curtis NJ, Walker DM. A case of aggressive multiple metachronous central giant cell granulomas of the jaws: differential diagnosis and management options. Int J Oral Maxillofac Surg 2005; 34:806-8. [PMID: 16157251 DOI: 10.1016/j.ijom.2005.01.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2003] [Revised: 10/08/2004] [Accepted: 01/25/2005] [Indexed: 11/16/2022]
Abstract
We describe multiple metachronous central giant cell granulomas in a 62-year-old man who has a first degree relative with a history of a solitary central giant cell granulomas. The patient presented in 1997 with a large central giant cell granuloma of the right maxilla which was treated with a partial maxillectomy. A small recurrence was then identified and the successful management of this is described. The patient has also a histologically confirmed central giant cell granuloma previously removed from the right body of the mandible and the left angle of the mandible. The differential diagnosis of multiple central giant cell granulomas of the jaw is considered. It is possible that the present case may indeed represent a new syndrome or subtype of multiple central giant cell granulomas. The problem of treating such aggressive sub-types of giant cell granulomas is also addressed in the context of recent advances of surgical and medical management.
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Guzowski M, Tumuluri K, Walker DM, Maloof A. Primary Orbital Ewing Sarcoma in a Middle-Aged Man. Ophthalmic Plast Reconstr Surg 2005; 21:449-51. [PMID: 16304525 DOI: 10.1097/01.iop.0000182303.15085.3b] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
A 54-year-old man presented with a painful left proptosis and a soft tissue mass at the inferolateral aspect of the left orbit with bone involvement. There was no clinical or investigational evidence of systemic disease. Both light microscopy and immunohistochemistry were required for the diagnosis of Ewing sarcoma. After failure of chemotherapy alone, management included extensive surgical excision and postoperative adjuvant radiotherapy and chemotherapy. Despite intervention, the patient died of widespread metastatic disease 17 months after initial presentation. Although rare, Ewing sarcoma should be included in the differential diagnosis of uniform round cell orbital tumors in adults.
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Molland JG, Morgan GJ, Walker DM, Lin BPC. Pleomorphic adenoma of the parotid and breast in a male patient. Pathology 2005; 37:263-5. [PMID: 16175906 DOI: 10.1080/00313020500099015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Walker DM. Oral mucosal immunology: an overview. ANNALS OF THE ACADEMY OF MEDICINE, SINGAPORE 2004; 33:27-30. [PMID: 15389303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
The primary function of the immune system of the mouth is to protect the teeth, jaws, gingivae and oral mucosa against infection. These host defences vary in the different oral microenvironments or domains represented by the oral mucosa, saliva and gingival crevice. This review aims to consider and contrast the main immune components in each domain and cites examples of oral diseases where the immune response is defective.
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Hyam DM, Conway RC, Sathiyaseelan Y, Gebski V, Morgan GJ, Walker DM, Veness MJ. Tongue cancer: Do patients younger than 40 do worse? Aust Dent J 2003; 48:50-4. [PMID: 14640158 DOI: 10.1111/j.1834-7819.2003.tb00009.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND Debate continues as to whether being young confers a worse prognosis for patients with squamous cell carcinoma of the tongue. Recent papers have provided conflicting views in this debate. In this study we aimed to investigate if young age at the time of diagnosis of squamous cell carcinoma of the tongue confers a worse prognosis. METHODS Eligible patients were identified through the computer database of the Department of Radiation Oncology, Westmead Hospital, Sydney. All eligible patients were treated with radical intent. Using age 40 as a cut off multivariate and survival analysis was undertaken to compare age groups. RESULTS Median age at diagnosis was 60 years (range, 19-86 years) in 84 males (65 per cent) and 45 females (35 per cent). Median follow-up time was 43 months (range, 2.3-203 months). Fifteen patients (12 per cent) were aged <40 years. On univariate analysis stage and age were significant determinants of disease-specific survival. There was no difference in overall survival between the young (<40 years) and middle-aged groups (40-60 years). However, the young and the middle aged were both more likely to survive than the older age group (>60 years). On multivariate analysis age remained a significant factor for determining disease-specific survival, with the older age group 2.9 times more likely to die than the younger groups. CONCLUSION Young age (<40 years) did not portend to worse survival in comparison to older tongue cancer patients.
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McEwen A, Emmanuel C, Medbury H, Leick A, Walker DM, Zoellner H. Induction of contact-dependent endothelial apoptosis by osteosarcoma cells suggests a role for endothelial cell apoptosis in blood-borne metastasis. J Pathol 2003; 201:395-403. [PMID: 14595751 DOI: 10.1002/path.1457] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Although tumour cells are believed to migrate between endothelial cells early in metastasis, the possibility remains that endothelial apoptosis may also contribute to the tumour's breach of the vascular barrier. Although seemingly inconsistent with tumour angiogenesis, one publication describes the induction of contact-dependent apoptosis in cultured endothelium by tumour cells. The cell culture data are, however, open to challenge on technical grounds while there are no confirmatory reports. The present paper describes experiments overcoming these limitations. SAOS-2 human osteosarcoma cells and two rat carcinoma cell lines were co-cultured with human umbilical vein endothelial cells (HUVECs) and cultures labelled by surface lectin histochemistry for endothelium. The HUVEC culture density was determined and SAOS-2 cells, but not rat carcinoma cells, were found significantly to reduce HUVEC survival despite the release of potent growth factors as determined in separate experiments with tumour cell conditioned medium. Lectin labelling combined with light microscopy, transmission electron microscopy, flow cytometry for both lectin binding and DNA content, and DNA gel electrophoresis of SAOS-2/HUVEC co-cultures revealed extensive HUVEC apoptosis. These findings indicate contact-dependent endothelial apoptosis by SAOS-2, while this activity appeared weaker and overwhelmed by HUVEC proliferation with rat carcinoma cells. Importantly, this study supports the suggestion that endothelial apoptosis may be important for metastasis and suggests a complex interplay between endothelial proliferation and apoptosis in tumours.
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McIntyre HF, Barrett J, Murphy S, Wray R, Sutcliffe SJ, Walker DM. Across the interface: the hastings heart function clinic. Heart 2002; 88 Suppl 2:ii23-7. [PMID: 12213796 PMCID: PMC1876269 DOI: 10.1136/heart.88.suppl_2.ii23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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Logusch EW, Walker DM, McDonald JF, Leo GC, Franz JE. Synthesis of .alpha.- and .gamma.-alkyl-substituted phosphinothricins: potent new inhibitors of glutamine synthetase. J Org Chem 2002. [DOI: 10.1021/jo00252a034] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Phillion DP, Walker DM. Metalation Chemistry of N-Ethyl-N-(1-methoxy-2,2-dimethylpropyl)benzamides. A New Protective Group for Secondary Amides. J Org Chem 2002. [DOI: 10.1021/jo00131a020] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Chan SW, Collins S, Masters CL, Walker DM. Classical and variant Creutzfeldt-Jakob diseases and their potential impact on the practice of clinical dentistry in Australia. Aust Dent J 2001; 46:251-7. [PMID: 11838871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Following recent published evidence regarding the experimental transmission of prion diseases via blood transfusion, dental practitioners have expressed their concern about the potential impact of these transmissible spongiform encephalopathies on dental care provision. This review provides updated information on Creutzfeldt-Jakob disease and related disorders and highlights their potential significance for the practice of clinical dentistry. The current guidelines in Australia relating to infection control and clinical dental procedures are discussed together with recommended guidelines and considerations from the United Kingdom and the World Health Organization (WHO).
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Walker DM, Urbé S, Dove SK, Tenza D, Raposo G, Clague MJ. Characterization of MTMR3. an inositol lipid 3-phosphatase with novel substrate specificity. Curr Biol 2001; 11:1600-5. [PMID: 11676921 DOI: 10.1016/s0960-9822(01)00501-2] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Inositol lipids play key roles in many fundamental cellular processes that include growth, cell survival, motility, and membrane trafficking. Recent studies on the PTEN and Myotubularin proteins have underscored the importance of inositol lipid 3-phosphatases in cell function. Inactivating mutations in the genes encoding PTEN and Myotubularin are key steps in the progression of some cancers and in the onset of X-linked myotubular myopathy, respectively. Myotubularin-related protein 3 (MTMR3) shows extensive homology to Myotubularin, including the catalytic domain, but additionally possesses a C-terminal extension that includes a FYVE domain. We show that MTMR3 is an inositol lipid 3-phosphatase, with a so-far-unique substrate specificity. It is able to hydrolyze PtdIns3P and PtdIns3,5P2, both in vitro and when heterologously expressed in S. cerevisiae, and to thereby provide the first clearly defined route for the cellular production of PtdIns5P. Overexpression of a catalytically dead MTMR3 (C413S) in mammalian cells induces a striking formation of vacuolar compartments that enclose membranous structures that are highly concentrated in mutant proteins.
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Veness MJ, Morgan G, Collins AP, Walker DM. Calcifying epithelial odontogenic (Pindborg) tumor with malignant transformation and metastatic spread. Head Neck 2001; 23:692-6. [PMID: 11443753 DOI: 10.1002/hed.1097] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Pindborg tumors (calcifying epithelial odontogenic tumors) are uncommon neoplasms of odontogenic origin most often located in the posterior mandible. First described in detail in 1955 by Pindborg, these tumors are considered benign but can be locally aggressive in nature, with recurrence rates of 10% to 15% reported. The malignant form of this tumor is exceedingly rare. METHODS We describe the case of a 64-year-old woman initially treated for a painful infected left mandibular third molar. The patient underwent extraction of the tooth and excision of an associated soft tissue component. Subsequent histologic review identified a Pindborg tumor of the left posterior mandible. RESULTS After initial excision, this tumor recurred twice, with the recurrences exhibiting a progression to a malignant Pindborg tumor (odontogenic carcinoma) with vascular invasion and spread to a cervical lymph node. Further treatment involved radical surgery and adjuvant radiotherapy. At last review 12 months after treatment, the patient was disease free. CONCLUSIONS This article describes only the second case of odontogenic carcinoma. The transformation from benign to malignant histologic findings has not previously been documented in this tumor. The salient clinical features of this case are presented along with supportive pathologic and radiologic evidence.
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Meng Q, Henderson RF, Long L, Blair L, Walker DM, Upton PB, Swenberg JA, Walker VE. Mutagenicity at the Hprt locus in T cells of female mice following inhalation exposures to low levels of 1,3-butadiene. Chem Biol Interact 2001; 135-136:343-61. [PMID: 11397400 DOI: 10.1016/s0009-2797(01)00222-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A study was conducted to test the hypothesis that repeated low level exposures to 1,3-butadiene (BD), approaching the OSHA occupational threshold for this chemical, produce a significant mutagenic response in mice. Female B6C3F1 mice (4-5 weeks of age) were exposed by inhalation for 2 weeks (6 h/day, 5 days/week) to 0 or 3 ppm BD, and then necropsied at 4 weeks after the cessation of exposures to measure the frequency of mutations (MF) at the Hprt locus using the T-lymphocyte clonal assay. At necropsy, T cells were isolated from spleen and cultured in the presence of mitogen, growth factors, and a selection agent. Cells were scored for growth on days 8-9 after plating to determine cloning efficiencies (CEs) and Hprt MFs. There was a marginal but significant reduction in the growth of splenic T cells from mice exposed to 3 ppm (n=27) compared with control mice (n=24) (P=0.004), suggesting the occurrence of BD-induced cytotoxicity at this low exposure concentration. In addition, the average Hprt MF in mice exposed to 3 ppm BD [1.54+/-0.82 (S.D.)x10(-6)] was significantly increased by 1.6-fold over the average control value of 0.96+/-0.51 (S.D.)x10(-6) (P=0.004). Comparisons of these data to earlier Hprt mutagenicity studies of mice exposed to high concentrations of BD (where significant mutagenic but not cytotoxic effects were observed) indicate that the ability to detect the cytotoxic and mutagenic responses of T cells to low levels of BD was enhanced by using a much larger sample size than usual for both the control and treatment groups. Additional analyses of the quantitative relationships between CE and MF demonstrated that CE had no significant effect upon MF values in sham-exposed control mice or mice exposed to low-level BD. Furthermore, the approaches for assessing the impact of CE and clonality on Hprt MFs in these control and BD-exposed mice were applied with the same rigor as in in vivo Hprt mutagenicity studies in human children. The overall study results support the conclusion that short-term low-level BD exposure is mutagenic in the mouse.
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