Displaying all 11 publications

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  1. Thomson PJ, Goodson ML, Smith DR
    J. Oral Pathol. Med., 2017 Nov;46(10):902-910.
    PMID: 28891106 DOI: 10.1111/jop.12641
    BACKGROUND: Contemporary potentially malignant disorder management is based upon provisional histological diagnosis followed by interventional surgery to excise or ablate 'high-risk' mucosal lesions. Although the majority of patients achieve disease-free status post-treatment, others develop further or persistent disease unresponsive to intervention.

    METHODS: A detailed, retrospective clinico-pathological review of treatment resistant potentially malignant lesions, from a 590 patient cohort treated by CO2 laser surgery and followed for a mean of 7.3 years, was undertaken. Clinical outcome was determined at study census date (31 December 2014).

    RESULTS: A total of 87 patients (15%) exhibited PMD disease resistant to treatment: 34 (6%) became disease free following further treatment, whilst 53 (9%) had persistent disease despite intervention. Disease-free patients were younger, changed lesion appearance from erythroleukoplakia to leukoplakia (P = .004), developed further lesions at new sites, demonstrated reduction in dysplasia severity with time and required multiple treatments to achieve disease-free status (P = .0005). In contrast, persistent disease patients were older, male, often presented with proliferative verrucous leukoplakia (PVL) on gingival and alveolar sites, displayed less severe dysplasia initially and underwent laser ablation rather than excision (P = .027).

    CONCLUSION: Despite clinico-pathological profiling of treatment resistant patients, the precise inter-relationship between the inherent nature of potentially malignant disease and the external influence of treatment intervention remains obscure.

  2. Thomson PJ, Goodson ML, Smith DR
    J. Oral Pathol. Med., 2018 Jul;47(6):557-565.
    PMID: 29663518 DOI: 10.1111/jop.12716
    BACKGROUND: Clinically identifiable potentially malignant disorders (PMD) precede oral squamous cell carcinoma development. Oral lichenoid lesions (OLL) and proliferative verrucous leukoplakia (PVL) are specific precursor lesions believed to exhibit both treatment resistance and a high risk of malignant transformation (MT).

    METHODS: A retrospective review of 590 PMD patients treated in Northern England by CO2 laser surgery between 1996 and 2014 was carried out. Lesions exhibiting lichenoid or proliferative verrucous features were identified from the patient database and their clinicopathological features and outcome post-treatment determined at the study census date of 31 December 2014.

    RESULTS: One hundred and 98 patients were identified as follows: 118 OLL and 80 PVL, most frequently leukoplakia at ventrolateral tongue and floor of mouth sites, equally distributed between males and females. Most exhibited dysplasia on incision biopsy (72% OLL; 85% PVL) and were treated by laser excision rather than ablation (88.1% OLL; 86.25% PVL). OLL were more common in younger patients (OLL 57.1 year; PVL 62.25 years; P = .008) and more likely than PVL to present as erythroleukoplakia (OLL 15.3%; PVL 2.5%; P = .003). Whilst no significant difference was seen between OLL and PVL achieving disease-free status (69.5% and 65%, respectively; P = .55), this was less than the overall PMD cohort (74.2%). MT was identified in 2 OLL (1.7%) and 2 PVL (2.5%) during follow-up.

    CONCLUSION: One-third of PMD cases showed features of OLL or PVL, probably representing a disease presentation continuum. Post-treatment disease-free status was less common in OLL and PVL, although MT was infrequent.

  3. Goodson ML, Smith DR, Thomson PJ
    J. Oral Pathol. Med., 2017 Nov;46(10):896-901.
    PMID: 28833675 DOI: 10.1111/jop.12627
    BACKGROUND: Oral potentially malignant disorders (PMD) harbour unpredictable risk for squamous cell carcinoma development. Current management requires tissue biopsy for histopathology characterisation, dysplasia grading and targeted intervention to "high-risk" lesions, although evidence-based guidelines are limited and diagnoses subjective. This study investigated the use of adjunctive oral brush biopsy techniques during the management of PMD in a UK hospital population.

    METHODS: Retrospective review of a 310 PMD patient cohort presenting to Maxillofacial Surgery in Newcastle upon Tyne with new, single-site lesions between December 2009 and May 2014. Patients underwent Orcellex® brush biopsy and liquid-based cytology examination in addition to conventional biopsy techniques, with management proceeding along established care pathways. Patient demographics, cytology data, most significant histopathology diagnoses and clinical outcome were all documented at the study census date (31.12.15).

    RESULTS: A total of 170 male & 140 female patients (age range 18-91 years), exhibiting primarily leukoplakia (86.5%) at floor of mouth and ventrolateral tongue sites (44.9%), were identified. Management comprised: observation (49.7%), laser surgery (44.9%), antifungal treatment (3.5%) and Head & Neck clinic referral following cancer diagnosis (1.9%). Clinical outcomes were as follows: disease free (51.3%), persistent PMD (42.3%) and malignant transformation (6.4%). Histology and cytology diagnoses strongly correlated (r = .305). Treatment modality, lesion site, histology and cytology diagnoses were the best predictors of clinical outcome.

    CONCLUSIONS: Orcellex® brush cytology provides reliable diagnoses consistent with conventional histopathology and offers less invasive, adjunctive assessment appropriate for long-term monitoring of patients in specialist clinics.

  4. Thomson PJ, Goodson ML, Smith DR
    J. Oral Pathol. Med., 2017 Nov;46(10):888-895.
    PMID: 28833670 DOI: 10.1111/jop.12625
    BACKGROUND: Oral potentially malignant disorders harbour variable and unpredictable risk for squamous carcinoma development. Whilst current management strategies utilise histopathological diagnoses, dysplasia grading and targeted intervention for "high-risk" lesions, clinicians are unable to predict malignant potential.

    METHODS: Detailed, retrospective clinico-pathological analysis of potentially malignant lesions undergoing malignant transformation, from a 590 patient cohort treated by interventional laser surgery and followed for a mean of 7.3 years, was undertaken. Clinical outcome was documented at study census date (31 December 2014).

    RESULTS: A total of 99 patients (16.8%) developed cancer: 71 (12%) seen "unexpectedly" upon excision and 28 (4.8%) progressing to malignancy at a median of 87.3 months post-surgery. Thirty "unexpected" excisions were micro-invasive (42.3%) arising primarily in severely dysplastic precursors (75%) at ventro-lateral tongue and floor of mouth sites (54.5%); 1 patient (1.4%) had a cancer-related death, whilst 58 (81.7%) were disease free. A total of 19 of 28 "progressive" cancers (67.9%) arose at new sites, with erythroleukoplakia a significant predictor of malignancy (P = .0019). Nine (32.1%) developed at the same precursor site, with 6 (77.7%) on the ventro-lateral tongue and floor of mouth. Three (10.7%) were micro-invasive, 9 patients (32.1%) died from metastatic disease and 12 (42.9%) were disease free (P < .001).

    CONCLUSION: Squamous carcinoma may arise at the site of a precursor lesion as transformation or new-site development via field cancerisation. Whilst interventional surgery facilitates early diagnosis and treatment of occult disease, thus reducing risk from same-site transformation, new-site cancer is a significant long-term risk for patients with potentially malignant disorder.

  5. Behzadnia A, Smith DR, Goodson ML
    Educ Health (Abingdon), 2018 12 12;31(2):80-86.
    PMID: 30531049 DOI: 10.4103/efh.EfH_280_17
    Background: Learning approaches have been proposed to affect the experience of psychological stress among tertiary students in recent years. This relationship becomes important in stressful environments such as medical schools. However, the relationship between stress and learning approaches is not well understood, and often studies done cannot be generalized due to different sociocultural differences. In particular, no study in Malaysia has looked at learning approaches among medical students.

    Aims: To address this gap, we examined the relationship between perceived stress and learning approaches by considering sources of stress.

    Methodology: The Perceived Stress Scale (PSS-10), Medical Student Stressor Questionnaire, and the Revised Two-Factor Study Process Questionnaire were answered by the preclinical and final-year students studying MBBS in a Malaysian campus of British University.

    Results: Deep learning was positively and surface learning negatively associated with perception of coping with stress. In this study, neither approaches were associated with psychological stress as opposed to previous reports. We found surface learners to report higher level of stress associated with social stressors. We found students' self-perception of feeling incompetent and feeling they need to do well to be significant sources of stress.

    Discussion: Deep learning promotes psychological resilience. This is of paramount importance in learning environments where stress is highly prevalent such as medical school. Promotion of deep learning among medical students is required at earlier stages as they tend to solidify their approach through their university years and carry that approach beyond school into their workplace.
  6. Goodson ML, Smith DR, Thomson PJ
    J. Oral Pathol. Med., 2019 May 24.
    PMID: 31125457 DOI: 10.1111/jop.12881
    BACKGROUND: Nomograms are graphical calculating devices used to predict risk of malignant transformation (MT) or response to treatment during cancer management. To date, a nomogram has not been used to predict clinical outcome during oral potentially malignant disorder (PMD) treatment. The aim of this study was to create a nomogram for use by clinicians to predict the probability of MT, thereby facilitating accurate assessment of risk and objective decision-making during individual patient management.

    METHODS: Clinico-pathological data from a previously treated cohort of 590 newly presenting PMD patients were reviewed and clinical outcomes categorized as disease free, persistent PMD or MT. Multiple logistic regression was used to predict the probability of MT in the cohort using age, gender, lesion type, site and incision biopsy histopathological diagnoses. Internal validation and calibration of the model was performed using the bootstrap method (n = 1000), and bias-corrected indices of model performance were computed.

    RESULTS: Potentially malignant disorders were predominantly leukoplakias (79%), presenting most frequently at floor of mouth and lateral tongue sites (51%); 99 patients (17%) developed oral squamous cell carcinoma during the study period. The nomogram performed well when MT predictions were compared with patient outcome data, demonstrating good bias-corrected discrimination and calibration (Dxy  = 0.58; C = 0.790), with a sensitivity of 87% and specificity 63%, and a positive predictive value of 32% and negative predictive value 96%.

    CONCLUSION: The "Newcastle Nomogram" has been developed to predict the probability of MT in PMD, based on an internally validated statistical model. Based upon readily available and patient-specific clinico-pathological data, it provides clinicians with a pragmatic diagrammatic aid for clinical decision-making during diagnosis and management of PMD.

  7. Pulmanausahakul R, Roytrakul S, Auewarakul P, Smith DR
    Int. J. Infect. Dis., 2011 Oct;15(10):e671-6.
    PMID: 21775183 DOI: 10.1016/j.ijid.2011.06.002
    In the last few years, chikungunya has become a major problem in Southeast Asia, with large numbers of cases being reported in Singapore, Malaysia, and Thailand. Much of the current epidemic of chikungunya in Southeast Asia is being driven by the emergence of a strain of chikungunya virus that originated in Africa and spread to islands in the Indian Ocean, as well as to India and Sri Lanka, and then onwards to Southeast Asia. There is currently no specific treatment for chikungunya and no vaccine is available for this disease. This review seeks to provide a short update on the reemergence of chikungunya in Southeast Asia and the prospects for control of this disease.
  8. Lithanatudom SK, Chaowasku T, Nantarat N, Jaroenkit T, Smith DR, Lithanatudom P
    Sci Rep, 2017 07 27;7(1):6716.
    PMID: 28751754 DOI: 10.1038/s41598-017-07045-7
    Dimocarpus longan, commonly known as the longan, belongs to the family Sapindaceae, and is one of the most economically important fruits commonly cultivated in several regions in Asia. There are various cultivars of longan throughout the Thai-Malay peninsula region, but until now no phylogenetic analysis has been undertaken to determine the genetic relatedness of these cultivars. To address this issue, 6 loci, namely ITS2, matK, rbcL, trnH-psbA, trnL-I and trnL-trnF were amplified and sequenced from 40 individuals consisting of 26 longan cultivars 2 types of lychee and 8 herbarium samples. The sequencing results were used to construct a phylogenetic tree using the neighbor-joining (NJ), maximum likelihood (ML) and Bayesian inference (BI) criteria. The tree showed cryptic groups of D. longan from the Thailand-Malaysia region (Dimocarpus longan spp.). This is the first report of the genetic relationship of Dimocarpus based on multi-locus molecular markers and morphological characteristics. Multiple sequence alignments, phylogenetic trees and species delimitation support that Dimocarpus longan spp. longan var. obtusus and Dimocarpus longan spp. malesianus var. malesianus should be placed into a higher order and are two additional species in the genus Dimocarpus. Therefore these two species require nomenclatural changes as Dimocarpus malesianus and Dimocarpus obtusus, respectively.
  9. Petz LN, Turell MJ, Padilla S, Long LS, Reinbold-Wasson DD, Smith DR, et al.
    Am. J. Trop. Med. Hyg., 2014 Oct;91(4):666-71.
    PMID: 25114013 DOI: 10.4269/ajtmh.13-0218
    Tembusu virus (TMUV) is an important emerging arthropod-borne virus that may cause encephalitis in humans and has been isolated in regions of southeast Asia, including Malaysia, Thailand, and China. Currently, detection and identification of TMUV are limited to research laboratories, because quantitative rapid diagnostic assays for the virus do not exist. We describe the development of sensitive and specific conventional and real-time quantitative reverse transcription polymerase chain reaction assays for detecting TMUV RNA in infected cell culture supernatant and Culex tarsalis mosquitoes. We used this assay to document the replication of TMUV in Cx. tarsalis, where titers increased 1,000-fold 5 days after inoculation. These assays resulted in the detection of virus-specific RNA in the presence of copurified mosquito nucleic acids. The use of these rapid diagnostic assays may have future applications for field pathogen surveillance and may assist in early detection, diagnosis, and control of the associated arthropod-borne pathogens.
  10. Smith ES, Smith DR, Eyring C, Braileanu M, Smith-Connor KS, Ei Tan Y, et al.
    Neurobiol Learn Mem, 2018 Nov 29.
    PMID: 30502397 DOI: 10.1016/j.nlm.2018.11.007
    Rett Syndrome (RTT) is a genetic disorder that is caused by mutations in the x-linked gene coding for methyl-CpG-biding-protein 2 (MECP2) and that mainly affects females. Male and female transgenic mouse models of RTT have been studied extensively, and we have learned a great deal regarding RTT neuropathology and how MeCP2 deficiency may be influencing brain function and maturation. In this manuscript we review what is known concerning structural and coinciding functional and behavioral deficits in RTT and in mouse models of MeCP2 deficiency. We also introduce our own corroborating data regarding behavioral phenotype and morphological alterations in volume of the cortex and striatum and the density of neurons, aberrations in experience-dependent plasticity within the barrel cortex and the impact of MeCP2 loss on glial structure. We conclude that regional structural changes in genetic models of RTT show great similarity to the alterations in brain structure of patients with RTT. These region-specific modifications often coincide with phenotype onset and contribute to larger issues of circuit connectivity, progression, and severity. Although the alterations seen in mouse models of RTT appear to be primarily due to cell-autonomous effects, there are also non-cell autonomous mechanisms including those caused by MeCP2-deficient glia that negatively impact healthy neuronal function. Collectively, this body of work has provided a solid foundation on which to continue to build our understanding of the role of MeCP2 on neuronal and glial structure and function, its greater impact on neural development, and potential new therapeutic avenues.
  11. Klionsky DJ, Abdelmohsen K, Abe A, Abedin MJ, Abeliovich H, Acevedo Arozena A, et al.
    Autophagy, 2016;12(1):1-222.
    PMID: 26799652 DOI: 10.1080/15548627.2015.1100356
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