Displaying publications 41 - 60 of 111 in total

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  1. Duff-Farrier CRA, Mbanzibwa DR, Nanyiti S, Bunawan H, Pablo-Rodriguez JL, Tomlinson KR, et al.
    Mol Biotechnol, 2019 Feb;61(2):93-101.
    PMID: 30484144 DOI: 10.1007/s12033-018-0139-7
    Cassava brown streak disease (CBSD) has major impacts on yield and quality of the tuberous roots of cassava in Eastern and Central Arica. At least two Potyviridae species cause the disease: Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV). Cloned viral genome sequences known as infectious clones (ICs) have been important in the study of other viruses, both as a means of standardising infectious material and characterising viral gene function. IC construction is often technically challenging for Potyviridae due to sequence instability in E. coli. Here, we evaluate three methods for the construction of infectious clones for CBSD. Whilst a simple IC for in vitro transcription was made for UCBSV isolate 'Kikombe', such an approach failed to deliver full-length clones for CBSV isolates 'Nampula' or 'Tanza', necessitating more complex approaches for their construction. The ICs successfully generated symptomatic infection in the model host N. benthamiana and in the natural host cassava. This shows that whilst generating ICs for CBSV is still a technical challenge, a structured approach, evaluating both in vitro and in planta transcription systems should successfully deliver ICs, allowing further study into the symptomology and virulence factors in this important disease complex.
  2. Guan Y, Vossen A, Adachi I, Adamczyk K, Ahn JK, Aihara H, et al.
    Phys Rev Lett, 2019 Feb 01;122(4):042001.
    PMID: 30768311 DOI: 10.1103/PhysRevLett.122.042001
    We report the first observation of the spontaneous polarization of Λ and Λ[over ¯] hyperons transverse to the production plane in e^{+}e^{-} annihilation, which is attributed to the effect arising from a polarizing fragmentation function. For inclusive Λ/Λ[over ¯] production, we also report results with subtracted feed-down contributions from Σ^{0} and charm. This measurement uses a dataset of 800.4  fb^{-1} collected by the Belle experiment at or near a center-of-mass energy of 10.58 GeV. We observe a significant polarization that rises with the fractional energy carried by the Λ/Λ[over ¯] hyperon.
  3. Seong IS, Vahsen SE, Adachi I, Aihara H, Al Said S, Asner DM, et al.
    Phys Rev Lett, 2019 Jan 11;122(1):011801.
    PMID: 31012694 DOI: 10.1103/PhysRevLett.122.011801
    We report on the first Belle search for a light CP-odd Higgs boson, A^{0}, that decays into low mass dark matter, χ, in final states with a single photon and missing energy. We search for events produced via the dipion transition ϒ(2S)→ϒ(1S)π^{+}π^{-}, followed by the on-shell process ϒ(1S)→γA^{0} with A^{0}→χχ, or by the off-shell process ϒ(1S)→γχχ. Utilizing a data sample of 157.3×10^{6} ϒ(2S) decays, we find no evidence for a signal. We set limits on the branching fractions of such processes in the mass ranges M_{A^{0}}<8.97  GeV/c^{2} and M_{χ}<4.44  GeV/c^{2}. We then use the limits on the off-shell process to set competitive limits on WIMP-nucleon scattering in the WIMP mass range below 5  GeV/c^{2}.
  4. Adachi I, Adye T, Ahmed H, Ahn JK, Aihara H, Akar S, et al.
    Phys Rev Lett, 2018 Dec 28;121(26):261801.
    PMID: 30636113 DOI: 10.1103/PhysRevLett.121.261801
    We present first evidence that the cosine of the CP-violating weak phase 2β is positive, and hence exclude trigonometric multifold solutions of the Cabibbo-Kobayashi-Maskawa (CKM) Unitarity Triangle using a time-dependent Dalitz plot analysis of B^{0}→D^{(*)}h^{0} with D→K_{S}^{0}π^{+}π^{-} decays, where h^{0}∈{π^{0},η,ω} denotes a light unflavored and neutral hadron. The measurement is performed combining the final data sets of the BABAR and Belle experiments collected at the ϒ(4S) resonance at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. The data samples contain (471±3)×10^{6}BB[over ¯] pairs recorded by the BABAR detector and (772±11)×10^{6}BB[over ¯] pairs recorded by the Belle detector. The results of the measurement are sin2β=0.80±0.14(stat)±0.06(syst)±0.03(model) and cos2β=0.91±0.22(stat)±0.09(syst)±0.07(model). The result for the direct measurement of the angle β of the CKM Unitarity Triangle is β=[22.5±4.4(stat)±1.2(syst)±0.6(model)]°. The measurement assumes no direct CP violation in B^{0}→D^{(*)}h^{0} decays. The quoted model uncertainties are due to the composition of the D^{0}→K_{S}^{0}π^{+}π^{-} decay amplitude model, which is newly established by performing a Dalitz plot amplitude analysis using a high-statistics e^{+}e^{-}→cc[over ¯] data sample. CP violation is observed in B^{0}→D^{(*)}h^{0} decays at the level of 5.1 standard deviations. The significance for cos2β>0 is 3.7 standard deviations. The trigonometric multifold solution π/2-β=(68.1±0.7)° is excluded at the level of 7.3 standard deviations. The measurement resolves an ambiguity in the determination of the apex of the CKM Unitarity Triangle.
  5. Fulsom BG, Pedlar TK, Adachi I, Aihara H, Al Said S, Asner DM, et al.
    Phys Rev Lett, 2018 Dec 07;121(23):232001.
    PMID: 30576207 DOI: 10.1103/PhysRevLett.121.232001
    We report the observation of ϒ(2S)→γη_{b}(1S) decay based on an analysis of the inclusive photon spectrum of 24.7  fb^{-1} of e^{+}e^{-} collisions at the ϒ(2S) center-of-mass energy collected with the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider. We measure a branching fraction of B[ϒ(2S)→γη_{b}(1S)]=(6.1_{-0.7-0.6}^{+0.6+0.9})×10^{-4} and derive an η_{b}(1S) mass of 9394.8_{-3.1-2.7}^{+2.7+4.5}  MeV/c^{2}, where the uncertainties are statistical and systematic, respectively. The significance of our measurement is greater than 7 standard deviations, constituting the first observation of this decay mode.
  6. Choon SE, Der YS, Lai NLJ, Yu SEE, Yap XL, Nalini NM
    Med J Malaysia, 2018 08;73(4):220-225.
    PMID: 30121684 MyJurnal
    BACKGROUND: Acute generalised exanthematous pustulosis (AGEP) is a rare, cutaneous reaction characterised by sudden onset of numerous, non-follicular, sterile pustules on oedematous erythematous skin, accompanied by fever and neutrophilia. AGEP is predominantly drug-induced. Skin lesions appear rapidly within 1-3 days of drug exposure and upon drug withdrawal, resolve rapidly within 15 days.

    OBJECTIVE: To determine the clinical characteristics, culprit drugs and outcome of patients with AGEP.

    METHODS: A retrospective note review of all AGEP patients seen from 2001-2015.

    RESULTS: Among 21 AGEP patients, 76% were Malays, 9.5% Chinese, 9.5% Indians, and 5% Iban. Sixteen were females and 5 were males. Median age of patients was 40 years (IQR: 26). The main culprit drug was amoxicillin (10 cases), followed by cloxacillin (three cases), phenytoin (two cases) and one case each of carbamazepine, sulphasalazine, allopurinol, cephalexin, ceftriaxone, celecoxib and herbal product. The median time from drug initiation to onset of AGEP was 3 days (IQR: 5.5). Fever was documented in 52.4 %, mucosal involvement 9.5%, purpura 4.7% and blisters 4.7%. Neutrophilia was observed in 63.6% of patients and eosinophilia in 28.5%. While most patients required admission (67%), all achieved complete recovery within 15 days without any sequela.

    CONCLUSIONS: AGEP predominantly affects Malay females in this study. The most common culprit drug was amoxicillin. Our patients exhibited the classic clinical manifestations of AGEP and confirmed the generally benign nature of this reaction upon drug withdrawal. Although the overall prognosis is good, prompt diagnosis of AGEP is important because drug withdrawal is the mainstay therapy.

  7. Thorlacius L, Garg A, Ingram JR, Villumsen B, Theut Riis P, Gottlieb AB, et al.
    Br J Dermatol, 2018 03;178(3):715-721.
    PMID: 29080368 DOI: 10.1111/bjd.16093
    BACKGROUND: A core outcomes set (COS) is an agreed minimum set of outcomes that should be measured and reported in all clinical trials for a specific condition. Hidradenitis suppurativa (HS) has no agreed-upon COS. A central aspect in the COS development process is to identify a set of candidate outcome domains from a long list of items. Our long list had been developed from patient interviews, a systematic review of the literature and a healthcare professional survey, and initial votes had been cast in two e-Delphi surveys. In this manuscript, we describe two in-person consensus meetings of Delphi participants designed to ensure an inclusive approach to generation of domains from related items.

    OBJECTIVES: To consider which items from a long list of candidate items to exclude and which to cluster into outcome domains.

    METHODS: The study used an international and multistakeholder approach, involving patients, dermatologists, surgeons, the pharmaceutical industry and medical regulators. The study format was a combination of formal presentations, small group work based on nominal group theory and a subsequent online confirmation survey.

    RESULTS: Forty-one individuals from 13 countries and four continents participated. Nine items were excluded and there was consensus to propose seven domains: disease course, physical signs, HS-specific quality of life, satisfaction, symptoms, pain and global assessments.

    CONCLUSIONS: The HISTORIC consensus meetings I and II will be followed by further e-Delphi rounds to finalize the core domain set, building on the work of the in-person consensus meetings.

  8. Shalihin SE, Harun Z, Osman IF
    Malays Fam Physician, 2018;13(2):39-41.
    PMID: 30302184 MyJurnal
    Essential thrombocythemia is one of the myeloproliferative neoplasms. Palpable purpura is a rare manifestation that may delay diagnosis and treatment. We report a case of essential thrombocythemia in a 50-year-old man, who presented with recurrent thigh pain for the past one year with nonspecific localized purpura. His full blood count revealed isolated thrombocytosis of 880,000/µL with an impression of myeloproliferative disorder from peripheral blood film. He was referred urgently to the hematology team, which proceeded with a venesection. His condition improved with hydroxyurea. This was a rare case of chronic presentation of myeloproliferative neoplasm detected at a primary care clinic.
  9. Loo JSE, Emtage AL, Ng KW, Yong ASJ, Doughty SW
    J Mol Graph Model, 2017 Dec 29;80:38-47.
    PMID: 29306746 DOI: 10.1016/j.jmgm.2017.12.017
    GPCR crystal structures have become more readily accessible in recent years. However, homology models of GPCRs continue to play an important role as many GPCR structures remain unsolved. The new crystal structures now available provide not only additional templates for homology modelling but also the opportunity to assess the performance of homology models against their respective crystal structures and gain insight into the performance of such models. In this study we have constructed homology models from templates of various transmembrane sequence identities for eight GPCR targets to better understand the relationship between transmembrane sequence identity and model quality. Model quality was assessed relative to the crystal structure in terms of structural accuracy as well as performance in two typical structure-based drug design applications: ligand binding pose prediction and docking enrichment in virtual screening. Crystal structures significantly outperformed homology models in both assessments. Accurate ligand binding pose prediction was possible but difficult to achieve using homology models, even with the use of induced fit docking. In virtual screening using homology models still conferred significant enrichment compared to random selection, with a clear benefit also observed in using models optimized through induced fit docking. Our results indicate that while homology models that are reasonably accurate structurally can be constructed, without significant refinement homology models will be outperformed by crystal structures in ligand binding pose prediction and docking enrichment regardless of the template used, primarily due to the extremely high level of structural accuracy needed for such applications.
  10. Loo JSE, Lim SW, Ng YK, Tiong JJL
    Int J Pharm Pract, 2017 Dec;25(6):429-437.
    PMID: 28211115 DOI: 10.1111/ijpp.12352
    OBJECTIVES: To identify factors influencing the decisions of Malaysian first-year pharmacy undergraduate students in private higher education when choosing to pursue a degree in pharmacy as well as their choice of private university.

    METHODS: This cross-sectional study employed a validated, self-administered questionnaire which was administered to 543 first-year pharmacy students from nine different private universities. Factor analysis was utilised to extract key factors from the responses. Descriptive and inferential statistics were used to analyse the data.

    KEY FINDINGS: Eight factors motivating students' decision to study pharmacy emerged from the responses, accounting for 63.8% of the variance observed. Students were primarily motivated by intrinsic interests, with work conditions and profession attributes also exerting significant influence. In terms of choice of private university, nine factors were identified, accounting for 73.8% of the variance observed. The image of the school and university were most influential factors in this context, followed by university safety, programme attributes and financial factors.

    CONCLUSIONS: First-year pharmacy students in the private higher education sector are motivated by intrinsic interest when choosing to study pharmacy over other courses, while their choice of private university is influenced primarily by the image of the school and university.

  11. Latha S, Choon SE, Tey KE, Chee YN
    Med J Malaysia, 2017 12;72(6):345-349.
    PMID: 29308771 MyJurnal
    BACKGROUND: Cutaneous vasculitis is common, yet the risk factors for its chronicity have not been established.

    OBJECTIVE: To describe the clinical spectrum and identify risk factors for chronicity of cutaneous vasculitis.

    METHODS: Retrospective data analysis of 275 patients diagnosed with cutaneous vasculitis from January 2008 to December 2013.

    RESULTS: The mean age was 33.7 (±17.89) years, with female predominance. The majority of patients were Malays (67.3%). Skin biopsy was performed in 110 (40%) patients. The commonest sign was palpable purpura (30.6%). The aetiology remained elusive in 51.3% of patients. Common identifiable causes include infection (19.7%) and connective tissue disease (10.2%). Extracutaneous features were noted in 46.5% of patients. Erythrocyte sedimentation rate and antinuclear antibody were raised in 124 of 170 and 27 of 175 patients with documented results respectively. Cutaneous vasculitis was the presenting symptom in seven patients with newly diagnosed systemic lupus erythematosus. Anti Streptolysin O Titre was positive in 82 of 156 patients with documented results. Despite antibiotics, 31.7% of them had chronic lesions. Prednisolone alone was used in 20% of patients while 16.4% needed steroid-sparing agents. Most patients who needed systemic therapy (62%) had unidentifiable aetiology. Among the 155 patients who remained under follow up, 36.4% had chronic disease, one patient succumbed due to septicaemia, and the rest fully recovered within three months. The presence of ulcerative lesion was significantly associated with developing chronic vasculitis (p=0.003).

    CONCLUSION: The clinical spectrum of cutaneous vasculitis in our population was similar to other studies. Ulcerative lesion predicts a chronic outcome.

  12. Nielsen SSE, Siupka P, Georgian A, Preston JE, Tóth AE, Yusof SR, et al.
    J Vis Exp, 2017 09 24.
    PMID: 28994773 DOI: 10.3791/56277
    The aim of this protocol presents an optimized procedure for the purification and cultivation of pBECs and to establish in vitro blood-brain barrier (BBB) models based on pBECs in mono-culture (MC), MC with astrocyte-conditioned medium (ACM), and non-contact co-culture (NCC) with astrocytes of porcine or rat origin. pBECs were isolated and cultured from fragments of capillaries from the brain cortices of domestic pigs 5-6 months old. These fragments were purified by careful removal of meninges, isolation and homogenization of grey matter, filtration, enzymatic digestion, and centrifugation. To further eliminate contaminating cells, the capillary fragments were cultured with puromycin-containing medium. When 60-95% confluent, pBECs growing from the capillary fragments were passaged to permeable membrane filter inserts and established in the models. To increase barrier tightness and BBB characteristic phenotype of pBECs, the cells were treated with the following differentiation factors: membrane permeant 8-CPT-cAMP (here abbreviated cAMP), hydrocortisone, and a phosphodiesterase inhibitor, RO-20-1724 (RO). The procedure was carried out over a period of 9-11 days, and when establishing the NCC model, the astrocytes were cultured 2-8 weeks in advance. Adherence to the described procedures in the protocol has allowed the establishment of endothelial layers with highly restricted paracellular permeability, with the NCC model showing an average transendothelial electrical resistance (TEER) of 1249 ± 80 Ω cm2, and paracellular permeability (Papp) for Lucifer Yellow of 0.90 10-6 ± 0.13 10-6 cm sec-1 (mean ± SEM, n=55). Further evaluation of this pBEC phenotype showed good expression of the tight junctional proteins claudin 5, ZO-1, occludin and adherens junction protein p120 catenin. The model presented can be used for a range of studies of the BBB in health and disease and, with the highly restrictive paracellular permeability, this model is suitable for studies of transport and intracellular trafficking.
  13. Ashley SE, Tan HT, Vuillermin P, Dharmage SC, Tang MLK, Koplin J, et al.
    Allergy, 2017 Sep;72(9):1356-1364.
    PMID: 28213955 DOI: 10.1111/all.13143
    BACKGROUND: A defective skin barrier is hypothesized to be an important route of sensitization to dietary antigens and may lead to food allergy in some children. Missense mutations in the serine peptidase inhibitor Kazal type 5 (SPINK5) skin barrier gene have previously been associated with allergic conditions.

    OBJECTIVE: To determine whether genetic variants in and around SPINK5 are associated with IgE-mediated food allergy.

    METHOD: We genotyped 71 "tag" single nucleotide polymorphisms (tag-SNPs) within a region spanning ~263 kb including SPINK5 (~61 kb) in n=722 (n=367 food-allergic, n=199 food-sensitized-tolerant and n=156 non-food-allergic controls) 12-month-old infants (discovery sample) phenotyped for food allergy with the gold standard oral food challenge. Transepidermal water loss (TEWL) measures were collected at 12 months from a subset (n=150) of these individuals. SNPs were tested for association with food allergy using the Cochran-Mantel-Haenszel test adjusting for ancestry strata. Association analyses were replicated in an independent sample group derived from four paediatric cohorts, total n=533 (n=203 food-allergic, n=330 non-food-allergic), mean age 2.5 years, with food allergy defined by either clinical history of reactivity, 95% positive predictive value (PPV) or challenge, corrected for ancestry by principal components.

    RESULTS: SPINK5 variant rs9325071 (A⟶G) was associated with challenge-proven food allergy in the discovery sample (P=.001, OR=2.95, CI=1.49-5.83). This association was further supported by replication (P=.007, OR=1.58, CI=1.13-2.20) and by meta-analysis (P=.0004, OR=1.65). Variant rs9325071 is associated with decreased SPINK5 gene expression in the skin in publicly available genotype-tissue expression data, and we generated preliminary evidence for association of this SNP with elevated TEWL also.

    CONCLUSIONS: We report, for the first time, association between SPINK5 variant rs9325071 and challenge-proven IgE-mediated food allergy.

  14. Ashley SE, Tan HT, Peters R, Allen KJ, Vuillermin P, Dharmage SC, et al.
    Clin Exp Allergy, 2017 Aug;47(8):1032-1037.
    PMID: 28544327 DOI: 10.1111/cea.12942
    BACKGROUND: Food allergies pose a considerable world-wide public health burden with incidence as high as one in ten in 12-month-old infants. Few food allergy genetic risk variants have yet been identified. The Th2 immune gene IL13 is a highly plausible genetic candidate as it is central to the initiation of IgE class switching in B cells.

    OBJECTIVE: Here, we sought to investigate whether genetic polymorphisms at IL13 are associated with the development of challenge-proven IgE-mediated food allergy.

    METHOD: We genotyped nine IL13 "tag" single nucleotide polymorphisms (tag SNPs) in 367 challenge-proven food allergic cases, 199 food-sensitized tolerant cases and 156 non-food allergic controls from the HealthNuts study. 12-month-old infants were phenotyped using open oral food challenges. SNPs were tested using Cochran-Mantel-Haenszel test adjusted for ancestry strata. A replication study was conducted in an independent, co-located sample of four paediatric cohorts consisting of 203 food allergic cases and 330 non-food allergic controls. Replication sample phenotypes were defined by clinical history of reactivity, 95% PPV or challenge, and IL13 genotyping was performed.

    RESULTS: IL13 rs1295686 was associated with challenge-proven food allergy in the discovery sample (P=.003; OR=1.75; CI=1.20-2.53). This association was also detected in the replication sample (P=.03, OR=1.37, CI=1.03-1.82) and further supported by a meta-analysis (P=.0006, OR=1.50). However, we cannot rule out an association with food sensitization. Carriage of the rs1295686 variant A allele was also associated with elevated total plasma IgE.

    CONCLUSIONS AND CLINICAL RELAVANCE: We show for the first time, in two independent cohorts, that IL13 polymorphism rs1295686 (in complete linkage disequilibrium with functional variant rs20541) is associated with challenge-proven food allergy.

  15. Abdullah N, Abdul Murad NA, Mohd Haniff EA, Syafruddin SE, Attia J, Oldmeadow C, et al.
    Public Health, 2017 Aug;149:31-38.
    PMID: 28528225 DOI: 10.1016/j.puhe.2017.04.003
    OBJECTIVE: Malaysia has a high and rising prevalence of type 2 diabetes (T2D). While environmental (non-genetic) risk factors for the disease are well established, the role of genetic variations and gene-environment interactions remain understudied in this population. This study aimed to estimate the relative contributions of environmental and genetic risk factors to T2D in Malaysia and also to assess evidence for gene-environment interactions that may explain additional risk variation.
    STUDY DESIGN: This was a case-control study including 1604 Malays, 1654 Chinese and 1728 Indians from the Malaysian Cohort Project.
    METHODS: The proportion of T2D risk variance explained by known genetic and environmental factors was assessed by fitting multivariable logistic regression models and evaluating McFadden's pseudo R(2) and the area under the receiver-operating characteristic curve (AUC). Models with and without the genetic risk score (GRS) were compared using the log likelihood ratio Chi-squared test and AUCs. Multiplicative interaction between genetic and environmental risk factors was assessed via logistic regression within and across ancestral groups. Interactions were assessed for the GRS and its 62 constituent variants.
    RESULTS: The models including environmental risk factors only had pseudo R(2) values of 16.5-28.3% and AUC of 0.75-0.83. Incorporating a genetic score aggregating 62 T2D-associated risk variants significantly increased the model fit (likelihood ratio P-value of 2.50 × 10(-4)-4.83 × 10(-12)) and increased the pseudo R(2) by about 1-2% and AUC by 1-3%. None of the gene-environment interactions reached significance after multiple testing adjustment, either for the GRS or individual variants. For individual variants, 33 out of 310 tested associations showed nominal statistical significance with 0.001 
  16. Latha S, Choon SE
    Med J Malaysia, 2017 06;72(3):151-156.
    PMID: 28733562 MyJurnal
    INTRODUCTION: Cutaneous adverse drug reactions (cADRs) are common. There are only few studies on the incidence of cADRs in Malaysia.

    OBJECTIVE: To determine the incidence, clinical features and risk factors of cADRs among hospitalized patients.

    METHODS: A prospective study was conducted among medical inpatients from July to December 2014.

    RESULTS: A total of 43 cADRs were seen among 11 017 inpatients, yielding an incidence rate of 0.4%. cADR accounted for hospitalization in 26 patients. Previous history of cADR was present in 14 patients, with 50% exposed to the same drug taken previously. Potentially lifethreatening severe cutaneous adverse reactions (SCAR), namely drug reaction with eosinophilia and systemic symptoms (DRESS: 14 cases) and Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis (SJS/TEN: 6 cases) comprise almost 50% of cADRs. The commonest culprit drug group was antibiotics (37.2%), followed by anticonvulsants (18.6%). Cotrimoxazole, phenytoin and rifampicin were the main causative drugs for DRESS. Anticonvulsants were most frequently implicated in SJS/TEN (66.7%). Most cases had "probable" causality relationship with suspected drug (69.8%). The majority of cases were of moderate severity (65.1%), while 18.6% had severe reaction with 1 death recorded. Most cases were not preventable (76.7%). Older age (> 60 years) and mucosal involvement were significantly associated with a more severe reaction.

    CONCLUSION: The incidence of cADRs was 0.4%, with most cases classified as moderate severity and not preventable. The commonest reaction pattern was DRESS, while the main culprit drug group was antibiotics. Older age and mucosal membrane involvement predicts a severe drug reaction.

  17. Chong SE, Mohd Nikman A, Saedah A, Wan Mohd Nazaruddin WH, Kueh YC, Lim JA, et al.
    Br J Anaesth, 2017 05 01;118(5):799-801.
    PMID: 28510752 DOI: 10.1093/bja/aex108
  18. Chang CC, Ng CC, Too CL, Choon SE, Lee CK, Chung WH, et al.
    Pharmacogenomics J, 2017 03;17(2):170-173.
    PMID: 26927288 DOI: 10.1038/tpj.2016.10
    Phenytoin (PHT) is a common cause of severe cutaneous adverse reactions (SCARs), including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN) and drug reaction with eosinophilia and systemic symptoms (DRESS). Although HLA-B*15:02 is associated with PHT-induced SJS/TEN (PHT-SJS/TEN) in Han Chinese and Thais, the genetic basis for susceptibility to PHT-induced SCARs (PHT-SCAR) in other populations remains unclear. We performed a case-control association study by genotyping the human leukocyte antigen (HLA)-B alleles of 16 Malay PHT-SCAR patients (13 SJS/TEN and 3 DRESS), 32 PHT-tolerant controls and 300 healthy ethnicity-matched controls. A novel genetic biomarker, HLA-B*15:13, showed significant association with PHT-SJS/TEN (53.8%, 7/13 cases) (odds ratio (OR) 11.28, P=0.003) and PHT-DRESS (100%, 3/3 cases) (OR 59.00, P=0.003) when compared with PHT-tolerant controls (9.4%, 3/32 controls). We also confirmed HLA-B*15:02 association with PHT-SJS/TEN (61.5%, 8/13 cases vs 21.9%, 7/32 controls; OR 5.71, P=0.016) when compared with PHT-tolerant controls. These alleles may serve as markers to predict PHT-SCAR in Malays.
  19. Morton SE, Chiew YS, Pretty C, Moltchanova E, Scarrott C, Redmond D, et al.
    Math Biosci, 2017 02;284:21-31.
    PMID: 27301378 DOI: 10.1016/j.mbs.2016.06.001
    Randomised control trials have sought to seek to improve mechanical ventilation treatment. However, few trials to date have shown clinical significance. It is hypothesised that aside from effective treatment, the outcome metrics and sample sizes of the trial also affect the significance, and thus impact trial design. In this study, a Monte-Carlo simulation method was developed and used to investigate several outcome metrics of ventilation treatment, including 1) length of mechanical ventilation (LoMV); 2) Ventilator Free Days (VFD); and 3) LoMV-28, a combination of the other metrics. As these metrics have highly skewed distributions, it also investigated the impact of imposing clinically relevant exclusion criteria on study power to enable better design for significance. Data from invasively ventilated patients from a single intensive care unit were used in this analysis to demonstrate the method. Use of LoMV as an outcome metric required 160 patients/arm to reach 80% power with a clinically expected intervention difference of 25% LoMV if clinically relevant exclusion criteria were applied to the cohort, but 400 patients/arm if they were not. However, only 130 patients/arm would be required for the same statistical significance at the same intervention difference if VFD was used. A Monte-Carlo simulation approach using local cohort data combined with objective patient selection criteria can yield better design of ventilation studies to desired power and significance, with fewer patients per arm than traditional trial design methods, which in turn reduces patient risk. Outcome metrics, such as VFD, should be used when a difference in mortality is also expected between the two cohorts. Finally, the non-parametric approach taken is readily generalisable to a range of trial types where outcome data is similarly skewed.
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