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8 result(s) for "Lye, Victoria"
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Prostate external beam radiotherapy combined with high-dose-rate brachytherapy: dose-volume parameters from deformably-registered plans correlate with late gastrointestinal complications
Background Derivation of dose-volume correlated with toxicity for multi-modal treatments can be difficult due to the perceived need for voxel-by-voxel dose accumulation. With data available for a single-institution cohort with long follow-up, an investigation was undertaken into rectal dose-volume effects for gastrointestinal toxicities after deformably-registering each phase of a combined external beam radiotherapy (EBRT)/high-dose-rate (HDR) brachytherapy prostate treatment. Methods One hundred and eighteen patients received EBRT in 23 fractions of 2 Gy and HDR (TG43 algorithm) in 3 fractions of 6.5 Gy. Results for the Late Effects of Normal Tissues — Subjective, Objective, Management and Analytic toxicity assessments were available with a median follow-up of 72 months. The HDR CT was deformably-registered to the EBRT CT. Doses were corrected for dose fractionation. Rectum dose-volume histogram (DVH) parameters were calculated in two ways. (1) Distribution-adding: parameters were calculated after the EBRT dose distribution was 3D-summed with the registered HDR dose distribution. (2) Parameter-adding: the EBRT DVH parameters were added to HDR DVH parameters. Logistic regressions and Mann-Whitney U-tests were used to correlate parameters with late peak toxicity (dichotomised at grade 1 or 2). Results The 48–80, 40–63 and 49–55 Gy dose regions from distribution-adding were significantly correlated with rectal bleeding, urgency/tenesmus and stool frequency respectively. Additionally, urgency/tenesmus and anorectal pain were associated with the 25–26 Gy and 44–48 Gy dose regions from distribution-adding respectively. Parameter-adding also indicated the low-mid dose region was significantly correlated with stool frequency and proctitis. Conclusions This study confirms significant dose-histogram effects for gastrointestinal toxicities after including deformable registration to combine phases of EBRT/HDR prostate cancer treatment. The findings from distribution-adding were in most cases consistent with those from parameter-adding. The mid-high dose range and near maximum doses were important for rectal bleeding. The distribution-adding mid-high dose range was also important for stool frequency and urgency/tenesmus. We encourage additional studies in a variety of institutions using a variety of dose accumulation methods with appropriate inter-fraction motion management. Trial registration NCT NCT00193856 . Retrospectively registered 12 September 2005.
Registering prostate external beam radiotherapy with a boost from high-dose-rate brachytherapy: a comparative evaluation of deformable registration algorithms
Background Registering CTs for patients receiving external beam radiotherapy (EBRT) with a boost dose from high-dose-rate brachytherapy (HDR) can be challenging due to considerable image discrepancies (e.g. rectal fillings, HDR needles, HDR artefacts and HDR rectal packing materials). This study is the first to comparatively evaluate image processing and registration methods used to register the rectums in EBRT and HDR CTs of prostate cancer patients. The focus is on the rectum due to planned future analysis of rectal dose-volume response. Methods For 64 patients, the EBRT CT was retrospectively registered to the HDR CT with rigid registration and non-rigid registration methods in VelocityAI. Image processing was undertaken on the HDR CT and the rigidly-registered EBRT CT to reduce the impact of discriminating features on alternative non-rigid registration methods applied in the software suite for Deformable Image Registration and Adaptive Radiotherapy Research (DIRART) using the Horn-Schunck optical flow and Demons algorithms. The propagated EBRT-rectum structures were compared with the HDR structure using the Dice similarity coefficient (DSC), Hausdorff distance (HD) and average surface distance (ASD). The image similarity was compared using mutual information (MI) and root mean squared error (MSE). The displacement vector field was assessed via the Jacobian determinant (JAC). The post-registration alignments of rectums for 21 patients were visually assessed. Results The greatest improvement in the median DSC relative to the rigid registration result was 35 % for the Horn-Schunck algorithm with image processing. This algorithm also provided the best ASD results. The VelocityAI algorithms provided superior HD, MI, MSE and JAC results. The visual assessment indicated that the rigid plus deformable multi-pass method within VelocityAI resulted in the best rectum alignment. Conclusions The DSC, ASD and HD improved significantly relative to the rigid registration result if image processing was applied prior to DIRART non-rigid registrations, whereas VelocityAI without image processing provided significant improvements. Reliance on a single rectum structure-correspondence metric would have been misleading as the metrics were inconsistent with one another and visual assessments. It was important to calculate metrics for a restricted region covering the organ of interest. Overall, VelocityAI generated the best registrations for the rectum according to the visual assessment, HD, MI, MSE and JAC results.
Blood RNA analysis can increase clinical diagnostic rate and resolve variants of uncertain significance
Purpose Diagnosis of genetic disorders is hampered by large numbers of variants of uncertain significance (VUSs) identified through next-generation sequencing. Many such variants may disrupt normal RNA splicing. We examined effects on splicing of a large cohort of clinically identified variants and compared performance of bioinformatic splicing prediction tools commonly used in diagnostic laboratories. Methods Two hundred fifty-seven variants (coding and noncoding) were referred for analysis across three laboratories. Blood RNA samples underwent targeted reverse transcription polymerase chain reaction (RT-PCR) analysis with Sanger sequencing of PCR products and agarose gel electrophoresis. Seventeen samples also underwent transcriptome-wide RNA sequencing with targeted splicing analysis based on Sashimi plot visualization. Bioinformatic splicing predictions were obtained using Alamut, HSF 3.1, and SpliceAI software. Results Eighty-five variants (33%) were associated with abnormal splicing. The most frequent abnormality was upstream exon skipping (39/85 variants), which was most often associated with splice donor region variants. SpliceAI had greatest accuracy in predicting splicing abnormalities (0.91) and outperformed other tools in sensitivity and specificity. Conclusion Splicing analysis of blood RNA identifies diagnostically important splicing abnormalities and clarifies functional effects of a significant proportion of VUSs. Bioinformatic predictions are improving but still make significant errors. RNA analysis should therefore be routinely considered in genetic disease diagnostics.
Quantifying the impact of a broadly protective sarbecovirus vaccine in a future SARS-X pandemic
COVID-19 has underscored the need for more timely access to vaccines during future pandemics. This has motivated development of broad-spectrum vaccines providing protection against entire viral families, which could be stockpiled and deployed rapidly following detection. Using mathematical modelling, we assess the utility of a broadly protective sarbecovirus vaccine during a hypothetical SARS-X outbreak, for a range of implementation strategies including ring-vaccination, spatial-targeting and mass vaccination of high-risk groups. Broadly protective sarbecovirus vaccine ring- or spatial strategies alone are insufficient to contain epidemics driven by a SARS-CoV-2-like virus, but when paired with rapid isolation and quarantine, can achieve containment of a SARS-CoV-1-like virus. Where suppression fails, broadly protective sarbecovirus vaccine utilisation still reduces the effective reproduction number and slows epidemic growth - buying valuable time for health-system response and virus-specific vaccine development. Vaccination of high-risk populations with the broadly protective sarbecovirus vaccine ahead of virus-specific vaccine availability could reduce mortality and enable shorter and less stringent non-pharmaceutical interventions to be imposed; results are sensitive to vaccine properties (e.g., efficacy), health system capabilities (e.g. rollout speed) and timeline to virus-specific vaccine availability. Our modelling suggests that broadly protective sarbecovirus vaccine delivery to those aged 60+ years could have averted 21-78 % of COVID-19 deaths during the pandemic’s first year, depending on the size of the stockpile. Realising this potential impact will require investment in manufacturing, delivery capacity and equitable access ahead of future pandemics. Broad-spectrum vaccines have been proposed as a tool for rapid response to emerging infectious disease threats and are in pre-clinical development. Here, the authors use mathematical modelling to assess the potential impacts of broadly protective sarbecovirus vaccines for a hypothetical “SARS-X” outbreak.
A Comprehensive Analysis of Common Genetic Variation Around Six Candidate Loci for Intrahepatic Cholestasis of Pregnancy
Intrahepatic cholestasis of pregnancy (ICP) has a complex etiology with a significant genetic component. Heterozygous mutations of canalicular transporters occur in a subset of ICP cases and a population susceptibility allele (p.444A) has been identified in ABCB11. We sought to expand our knowledge of the detailed genetic contribution to ICP by investigation of common variation around candidate loci with biological plausibility for a role in ICP (ABCB4, ABCB11, ABCC2, ATP8B1, NR1H4, and FGF19). ICP patients (n=563) of white western European origin and controls (n=642) were analyzed in a case-control design. Single-nucleotide polymorphism (SNP) markers (n=83) were selected from the HapMap data set (Tagger, Haploview 4.1 (build 22)). Genotyping was performed by allelic discrimination assay on a robotic platform. Following quality control, SNP data were analyzed by Armitage's trend test. Cochran-Armitage trend testing identified six SNPs in ABCB11 together with six SNPs in ABCB4 that showed significant evidence of association. The minimum Bonferroni corrected P value for trend testing ABCB11 was 5.81×10(-4) (rs3815676) and for ABCB4 it was 4.6×10(-7)(rs2109505). Conditional analysis of the two clusters of association signals suggested a single signal in ABCB4 but evidence for two independent signals in ABCB11. To confirm these findings, a second study was performed in a further 227 cases, which confirmed and strengthened the original findings. Our analysis of a large cohort of ICP cases has identified a key role for common variation around the ABCB4 and ABCB11 loci, identified the core associations, and expanded our knowledge of ICP susceptibility.
Correction: Blood RNA analysis can increase clinical diagnostic rate and resolve variants of uncertain significance
An amendment to this paper has been published and can be accessed via a link at the top of the paper.An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Blood RNA analysis can increase clinical diagnostic rate andresolve variants of uncertain significance
PurposeDiagnosis of genetic disorders is hampered by large numbers of variants of uncertain significance (VUSs) identified through next-generation sequencing. Many such variants may disrupt normal RNA splicing. We examined effects on splicing of a large cohort of clinically identified variants and compared performance of bioinformatic splicing prediction tools commonly used in diagnostic laboratories.MethodsTwo hundred fifty-seven variants (coding and noncoding) were referred for analysis across three laboratories. Blood RNA samples underwent targeted reverse transcription polymerase chain reaction (RT-PCR) analysis with Sanger sequencing of PCR products and agarose gel electrophoresis. Seventeen samples also underwent transcriptome-wide RNA sequencing with targeted splicing analysis based on Sashimi plot visualization. Bioinformatic splicing predictions were obtained using Alamut, HSF 3.1, and SpliceAI software.ResultsEighty-five variants (33%) were associated with abnormal splicing. The most frequent abnormality was upstream exon skipping (39/85 variants), which was most often associated with splice donor region variants. SpliceAI had greatest accuracy in predicting splicing abnormalities (0.91) and outperformed other tools in sensitivity and specificity.ConclusionSplicing analysis of blood RNA identifies diagnostically important splicing abnormalities and clarifies functional effects of a significant proportion of VUSs. Bioinformatic predictions are improving but still make significant errors. RNA analysis should therefore be routinely considered in genetic disease diagnostics.
Knowledge and Reported Use of Antibiotics Amongst Immigrant Ethnic Groups in New Zealand
Background Over-use and misuse of antibiotics are major causes of antibiotic resistance. This study explored the understanding and reported use of antibiotics amongst three ethnic groups in New Zealand. Methods Questionnaire survey of 300 Indian, Egyptian, and Korean people. Results Most people (73.3%) knew that antibiotics killed bacteria, but other incorrect responses were also common. A range of medicines were mistakenly identified as antibiotics. Nearly half the sample (43.3%) believed colds and flu were caused by bacteria. Only 45.4% were sure that antibiotics were not useful for colds and flu. A minority of participants knew about antibiotic resistance. There were significant differences between groups, with Koreans having lower levels of understanding. Discussion Interventions to improve use of antibiotics need to be pitched at a very basic level of knowledge, and need to be targeted towards particular ethnic groups, particularly those in whose home countries antibiotics are widely available without prescription.