91 results on '"Ng BL"'
Search Results
2. Prompt use of mechanical cardiopulmonary resuscitation in out-of-hospital cardiac arrest: the MECCA study report
- Author
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Anantharaman, V, primary, Ng, BL, additional, Ang, SH, additional, Lee, CY, additional, Leong, SH, additional, Ong, ME, additional, Chua, SJ, additional, Rabind, AC, additional, Anjali, NB, additional, and Hao, Y, additional
- Published
- 2017
- Full Text
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3. Genome Sequencing and Analysis of the Tasmanian Devil and Its Transmissible Cancer
- Author
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Murchison, EP, Schulz-Trieglaff, OB, Ning, Z, Alexandrov, LB, Bauer, MJ, Fu, B, Hims, M, Ding, Z, Ivakhno, S, Stewart, C, Ng, BL, Wong, W, Aken, B, White, S, Alsop, A, Becq, J, Bignell, GR, Cheetham, RK, Cheng, W, Connor, TR, Cox, AJ, Feng, Z-P, Gu, Y, Grocock, RJ, Harris, SR, Khrebtukova, I, Kingsbury, Z, Kowarsky, M, Kreiss, A, Luo, S, Marshall, J, McBride, DJ, Murray, L, Pearse, A-M, Raine, K, Rasolonjatovo, I, Shaw, R, Tedder, P, Tregidgo, C, Vilella, AJ, Wedge, DC, Woods, GM, Gormley, N, Humphray, S, Schroth, G, Smith, G, Hall, K, Searle, SMJ, Carter, NP, Papenfuss, AT, Futreal, PA, Campbell, PJ, Yang, F, Bentley, DR, Evers, DJ, Stratton, MR, Murchison, EP, Schulz-Trieglaff, OB, Ning, Z, Alexandrov, LB, Bauer, MJ, Fu, B, Hims, M, Ding, Z, Ivakhno, S, Stewart, C, Ng, BL, Wong, W, Aken, B, White, S, Alsop, A, Becq, J, Bignell, GR, Cheetham, RK, Cheng, W, Connor, TR, Cox, AJ, Feng, Z-P, Gu, Y, Grocock, RJ, Harris, SR, Khrebtukova, I, Kingsbury, Z, Kowarsky, M, Kreiss, A, Luo, S, Marshall, J, McBride, DJ, Murray, L, Pearse, A-M, Raine, K, Rasolonjatovo, I, Shaw, R, Tedder, P, Tregidgo, C, Vilella, AJ, Wedge, DC, Woods, GM, Gormley, N, Humphray, S, Schroth, G, Smith, G, Hall, K, Searle, SMJ, Carter, NP, Papenfuss, AT, Futreal, PA, Campbell, PJ, Yang, F, Bentley, DR, Evers, DJ, and Stratton, MR
- Abstract
The Tasmanian devil (Sarcophilus harrisii), the largest marsupial carnivore, is endangered due to a transmissible facial cancer spread by direct transfer of living cancer cells through biting. Here we describe the sequencing, assembly, and annotation of the Tasmanian devil genome and whole-genome sequences for two geographically distant subclones of the cancer. Genomic analysis suggests that the cancer first arose from a female Tasmanian devil and that the clone has subsequently genetically diverged during its spread across Tasmania. The devil cancer genome contains more than 17,000 somatic base substitution mutations and bears the imprint of a distinct mutational process. Genotyping of somatic mutations in 104 geographically and temporally distributed Tasmanian devil tumors reveals the pattern of evolution and spread of this parasitic clonal lineage, with evidence of a selective sweep in one geographical area and persistence of parallel lineages in other populations.
- Published
- 2012
4. Distributed Downlink Beamforming With Cooperative Base Stations
- Author
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Ng, BL, Evans, JS, Hanly, SV, Aktas, D, Ng, BL, Evans, JS, Hanly, SV, and Aktas, D
- Published
- 2008
5. Definition of the zebrafish genome using flow cytometry and cytogenetic mapping
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Freeman, JL, Adeniyi, A, Banerjee, R, Dallaire, S, Maguire, SF, Chi, J, Ng, BL, Zepeda, C, Scott, CE, Humphray, S, Rogers, J, Zhou, Y, Zon, LI, Carter, NP, Yang, F, Lee, C, Freeman, JL, Adeniyi, A, Banerjee, R, Dallaire, S, Maguire, SF, Chi, J, Ng, BL, Zepeda, C, Scott, CE, Humphray, S, Rogers, J, Zhou, Y, Zon, LI, Carter, NP, Yang, F, and Lee, C
- Abstract
BACKGROUND: The zebrafish (Danio rerio) is an important vertebrate model organism system for biomedical research. The syntenic conservation between the zebrafish and human genome allows one to investigate the function of human genes using the zebrafish model. To facilitate analysis of the zebrafish genome, genetic maps have been constructed and sequence annotation of a reference zebrafish genome is ongoing. However, the duplicative nature of teleost genomes, including the zebrafish, complicates accurate assembly and annotation of a representative genome sequence. Cytogenetic approaches provide "anchors" that can be integrated with accumulating genomic data. RESULTS: Here, we cytogenetically define the zebrafish genome by first estimating the size of each linkage group (LG) chromosome using flow cytometry, followed by the cytogenetic mapping of 575 bacterial artificial chromosome (BAC) clones onto metaphase chromosomes. Of the 575 BAC clones, 544 clones localized to apparently unique chromosomal locations. 93.8% of these clones were assigned to a specific LG chromosome location using fluorescence in situ hybridization (FISH) and compared to the LG chromosome assignment reported in the zebrafish genome databases. Thirty-one BAC clones localized to multiple chromosomal locations in several different hybridization patterns. From these data, a refined second generation probe panel for each LG chromosome was also constructed. CONCLUSION: The chromosomal mapping of the 575 large-insert DNA clones allows for these clones to be integrated into existing zebrafish mapping data. An accurately annotated zebrafish reference genome serves as a valuable resource for investigating the molecular basis of human diseases using zebrafish mutant models.
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- 2007
6. On the Capacity of Cellular Networks with Global LMMSE Receiver
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NG, BL, EVANS, J, HANLY, S, NG, BL, EVANS, J, and HANLY, S
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- 2007
7. Expression of mammalian GPCRs in C. elegans generates novel behavioural responses to human ligands
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Teng, MS, Dekkers, MPJ (Martijn), Ng, BL, Rademakers, Suzanne, Jansen, Gert, Fraser, AG, McCafferty, J, Teng, MS, Dekkers, MPJ (Martijn), Ng, BL, Rademakers, Suzanne, Jansen, Gert, Fraser, AG, and McCafferty, J
- Published
- 2006
8. A plasmin generation method for the determination of tissue plasminogen activator (t-PA) activity in blood
- Author
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Koh, SCL, primary, Yuen, R, additional, Viegas, OAC, additional, Chua, SE, additional, Ng, BL, additional, Sen, DK, additional, and Ratnam, SS, additional
- Published
- 1989
- Full Text
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9. Novel stem cell technologies are powerful tools to understand the impact of human factors on Plasmodium falciparum malaria.
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Pance A, Ng BL, Mwikali K, Koutsourakis M, Agu C, Rouhani FJ, Montandon R, Law F, Ponstingl H, and Rayner JC
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- Humans, Plasmodium falciparum genetics, Erythrocytes parasitology, Stem Cells, Malaria, Falciparum parasitology, Malaria parasitology
- Abstract
Plasmodium falciparum parasites have a complex life cycle, but the most clinically relevant stage of the disease is the invasion of erythrocytes and the proliferation of the parasite in the blood. The influence of human genetic traits on malaria has been known for a long time, however understanding the role of the proteins involved is hampered by the anuclear nature of erythrocytes that makes them inaccessible to genetic tools. Here we overcome this limitation using stem cells to generate erythroid cells with an in-vitro differentiation protocol and assess parasite invasion with an adaptation of flow cytometry to detect parasite hemozoin. We combine this strategy with reprogramming of patient cells to Induced Pluripotent Stem Cells and genome editing to understand the role of key genes and human traits in malaria infection. We show that deletion of basigin ablates invasion while deletion of ATP2B4 has a minor effect and that erythroid cells from reprogrammed patient-derived HbBart α-thalassemia samples poorly support infection. The possibility to obtain patient-secific and genetically modifed erythoid cells offers an unparalleled opportunity to study the role of human genes and polymorphisms in malaria allowing preservation of the genomic background to demonstrate their function and understand their mechanisms., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2023 Pance, Ng, Mwikali, Koutsourakis, Agu, Rouhani, Montandon, Law, Ponstingl and Rayner.)
- Published
- 2023
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10. A plasma protein signature associated with cognitive function in men without severe cognitive impairment.
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Mehta K, Mohebbi M, Pasco JA, Williams LJ, Sui SX, Walder K, Ng BL, and Gupta VB
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- Male, Humans, Middle Aged, Proteomics, Cognition, Blood Proteins, Alzheimer Disease genetics, Cognitive Dysfunction genetics
- Abstract
Background: A minimally invasive blood-based assessment of cognitive function could be a promising screening strategy to identify high-risk groups for the incidence of Alzheimer's disease., Methods: The study included 448 cognitively unimpaired men (mean age 64.1 years) drawn from the Geelong Osteoporosis Study. A targeted mass spectrometry-based proteomic assay was performed to measure the abundance levels of 269 plasma proteins followed by linear regression analyses adjusted for age and APOE ε4 carrier status to identify the biomarkers related to overall cognitive function. Furthermore, two-way interactions were conducted to see whether Alzheimer's disease-linked genetic variants or health conditions modify the association between biomarkers and cognitive function., Results: Ten plasma proteins showed an association with overall cognitive function. This association was modified by allelic variants in genes ABCA7, CLU, BDNF and MS4A6A that have been previously linked to Alzheimer's disease. Modifiable health conditions such as mood disorders and poor bone health, which are postulated to be risk factors for Alzheimer's disease, also impacted the relationship observed between protein marker levels and cognition. In addition to the univariate analyses, an 11-feature multianalyte model was created using the least absolute shrinkage and selection operator regression that identified 10 protein features and age associated with cognitive function., Conclusions: Overall, the present study revealed plasma protein candidates that may contribute to the development of a blood-based screening test for identifying early cognitive changes. This study also highlights the importance of considering other risk factors in elucidating the relationship between biomarkers and cognition, an area that remains largely unexplored., (© 2023. BioMed Central Ltd., part of Springer Nature.)
- Published
- 2023
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11. Chromosome Analysis and Sorting Using Conventional Flow Cytometers.
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Ng BL
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- Propidium, Chromosomes chemistry, Karyotyping, Fluorescent Dyes, Chromomycin A3, DNA analysis
- Abstract
The fluorescent dyes Hoechst (HO) and Chromomycin A3 (CA3) are commonly used for bivariate flow karyotyping to distinguish individual chromosomes from one another based on differences in base composition and DNA content. However, analysis of chromosomes using this fluorescent dye combination requires a flow cytometer equipped with lasers of specific wavelengths and higher power than is typical of conventional flow cytometers. This unit presents a chromosome staining technique with a dye combination of DAPI and propidium iodide (PI). Chromosomes stained using this dye combination can be analyzed on conventional flow cytometers equipped with a typical configuration of lasers and optics. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Cell culture and metaphase harvest of suspension cell line Alternate Protocol 1: Cell culture and metaphase harvest of adherent cell line Basic Protocol 2: Preparation of chromosome suspension using polyamine isolation buffer Basic Protocol 3: Staining chromosomes with DAPI and propidium iodide Alternate Protocol 2: Staining chromosomes with Hoechst and Chromomycin A3 Basic Protocol 4: Bivariate flow karyotyping on a cell analyzer Basic Protocol 5: Bivariate flow karyotyping on a cell sorter Basic Protocol 6: Purification of flow-sorted chromosomes., (© 2023 The Authors. Current Protocols published by Wiley Periodicals LLC.)
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- 2023
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12. Impact of Mood Disorder History and Bone Health on Cognitive Function Among Men Without Dementia.
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Mehta K, Mohebbi M, Pasco JA, Williams LJ, Walder K, Ng BL, and Gupta VB
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- Humans, Male, Bone Density, Absorptiometry, Photon, Cognition, Osteoporosis diagnostic imaging, Dementia
- Abstract
Background: Poor cognitive function, a major disabling condition of older age, is often considered a prodromal feature of dementia. High mortality and the lack of a cure for dementia have necessitated a focus on the identification of potentially modifiable risk factors. Mental and physical health conditions such as mood disorders and bone loss have been previously linked with poor cognition individually although their combined effect remains largely unknown., Objective: Considering the multifactorial nature of dementia pathology, we investigated whether mood disorders, bone health and their interaction are associated with cognitive function in a population-based sample of men., Methods: Four hundred and forty-two male participants were drawn from the Geelong Osteoporosis Study. Cognitive function was assessed using the CogState Brief Battery, which measured cognitive performance across four domains and was used to compute overall cognitive function. Mood disorders and hip bone mineral density (BMD) were determined using a semi-structured clinical interview and dual-energy X-ray absorptiometry, respectively., Results: Hip BMD (Bcoeff = 0.56, 95% CI: [0.07, 1.05], p = 0.025) but not mood disorder (Bcoeff = -0.50, 95% CI: [-0.20, 0.10], p = 0.529) was associated with overall cognitive function after accounting for potential confounders. Interaction effects were observed between the two exposures (Bcoeff = -1.37, 95% CI: [-2.49, -0.26], p = 0.016) suggesting that individuals without a mood disorder displayed better cognitive performance with increasing BMD, while those with a lifetime history of mood disorder displayed poorer cognitive function with increasing BMD., Conclusions: These findings highlight the importance of exploring interactions among potentially modifiable health conditions associated with cognitive function.
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- 2023
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13. Neurofilament light levels predict clinical progression and death in multiple system atrophy.
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Chelban V, Nikram E, Perez-Soriano A, Wilke C, Foubert-Samier A, Vijiaratnam N, Guo T, Jabbari E, Olufodun S, Gonzalez M, Senkevich K, Laurens B, Péran P, Rascol O, Le Traon AP, Todd EG, Costantini AA, Alikhwan S, Tariq A, Ng BL, Muñoz E, Painous C, Compta Y, Junque C, Segura B, Zhelcheska K, Wellington H, Schöls L, Jaunmuktane Z, Kobylecki C, Church A, Hu MTM, Rowe JB, Leigh PN, Massey L, Burn DJ, Pavese N, Foltynie T, Pchelina S, Wood N, Heslegrave AJ, Zetterberg H, Bocchetta M, Rohrer JD, Marti MJ, Synofzik M, Morris HR, Meissner WG, and Houlden H
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- Humans, Cohort Studies, Cross-Sectional Studies, Intermediate Filaments, Neurofilament Proteins, Biomarkers, Disease Progression, Multiple System Atrophy
- Abstract
Disease-modifying treatments are currently being trialled in multiple system atrophy. Approaches based solely on clinical measures are challenged by heterogeneity of phenotype and pathogenic complexity. Neurofilament light chain protein has been explored as a reliable biomarker in several neurodegenerative disorders but data on multiple system atrophy have been limited. Therefore, neurofilament light chain is not yet routinely used as an outcome measure in multiple system atrophy. We aimed to comprehensively investigate the role and dynamics of neurofilament light chain in multiple system atrophy combined with cross-sectional and longitudinal clinical and imaging scales and for subject trial selection. In this cohort study, we recruited cross-sectional and longitudinal cases in a multicentre European set-up. Plasma and CSF neurofilament light chain concentrations were measured at baseline from 212 multiple system atrophy cases, annually for a mean period of 2 years in 44 multiple system atrophy patients in conjunction with clinical, neuropsychological and MRI brain assessments. Baseline neurofilament light chain characteristics were compared between groups. Cox regression was used to assess survival; receiver operating characteristic analysis to assess the ability of neurofilament light chain to distinguish between multiple system atrophy patients and healthy controls. Multivariate linear mixed-effects models were used to analyse longitudinal neurofilament light chain changes and correlated with clinical and imaging parameters. Polynomial models were used to determine the differential trajectories of neurofilament light chain in multiple system atrophy. We estimated sample sizes for trials aiming to decrease neurofilament light chain levels. We show that in multiple system atrophy, baseline plasma neurofilament light chain levels were better predictors of clinical progression, survival and degree of brain atrophy than the neurofilament light chain rate of change. Comparative analysis of multiple system atrophy progression over the course of disease, using plasma neurofilament light chain and clinical rating scales, indicated that neurofilament light chain levels rise as the motor symptoms progress, followed by deceleration in advanced stages. Sample size prediction suggested that significantly lower trial participant numbers would be needed to demonstrate treatment effects when incorporating plasma neurofilament light chain values into multiple system atrophy clinical trials in comparison to clinical measures alone. In conclusion, neurofilament light chain correlates with clinical disease severity, progression and prognosis in multiple system atrophy. Combined with clinical and imaging analysis, neurofilament light chain can inform patient stratification and serve as a reliable biomarker of treatment response in future multiple system atrophy trials of putative disease-modifying agents., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Guarantors of Brain.)
- Published
- 2022
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14. Genetic polymorphism in BIN1 rather than APOE is associated with poor recognition memory among men without dementia.
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Mehta K, Mohebbi M, Pasco JA, Williams LJ, Walder K, Ng BL, and Gupta VB
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- Male, Humans, Aged, Apolipoprotein E4 genetics, Genotype, Memory Disorders, Polymorphism, Genetic, Neuropsychological Tests, Nuclear Proteins genetics, Tumor Suppressor Proteins genetics, Adaptor Proteins, Signal Transducing genetics, Alzheimer Disease genetics, Alzheimer Disease psychology
- Abstract
Although several genetic polymorphisms have been linked with the risk of Alzheimer's disease, less is known about their impact on cognitive performance among cognitively healthy individuals. Our aim was to investigate the association of the genetic variant, rs744373 in the bridging integrator 1 gene (BIN1), the strongest genetic risk factor for Alzheimer's disease after the APOE ε4 allele, with different cognitive domains among non-demented older men. Cognitive function was measured using the CogState Brief Battery, which assessed cognitive performance across four domains: psychomotor function, visual attention, recognition memory and working memory. Linear regression analysis revealed that individuals with the BIN1 risk allele performed poorly on the recognition memory task as compared to those without the risk allele. However, this was in contrast with the individuals who harboured the APOE ε4 risk allele as they displayed better performance on the recognition task in comparison to those without the ε4 risk allele. To the best of our knowledge, this is the first study that demonstrates genetic variation in BIN1 to be a better predictor of recognition memory than APOE, which remains the biggest genetic risk factor for Alzheimer's disease., (© 2022. The Author(s).)
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- 2022
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15. Depression and bone loss as risk factors for cognitive decline: A systematic review and meta-analysis.
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Mehta K, Thandavan SP, Mohebbi M, Pasco JA, Williams LJ, Walder K, Ng BL, and Gupta VB
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- Depression epidemiology, Humans, Longitudinal Studies, Risk Factors, Alzheimer Disease diagnosis, Cognitive Dysfunction diagnosis
- Abstract
Background: Depression is linked to Alzheimer's disease (AD) but it is unclear whether depression is also associated with cognitive decline in the preclinical phase and mild cognitive impairment (MCI). Previous meta-analyses have only investigated AD as an outcome without accounting for individuals showing cognitive decline that does not meet the diagnostic criteria for AD. Other potentially modifiable risk factors such as bone loss have also been less explored and there remains uncertainty around their temporal relationship with cognitive decline., Aims: To conduct a systematic review and meta-analysis investigating depression and bone loss as risk factors for subsequent cognitive decline., Methods: A comprehensive search strategy was developed and applied using four databases; MEDLINE Complete, Embase, PsycINFO and CINAHL Complete. The pooled summary effects were estimated as odds ratios with 95% confidence intervals using a random-effects model. The study protocol was registered with PROSPERO (ID: CRD42020159369)., Results: A total of 75 longitudinal cohort studies were identified for meta-analysis, of which 70 examined the impact of depression on cognitive decline and five examined the impact of bone loss. Prior exposure to depression was found to be associated with cognitive score reduction (OR 1.33 95% CI 1.17, 1.51), MCI incidence (OR 1.52 95% CI 1.28, 1.79) and AD incidence (OR 1.79 95% CI 1.46, 2.2). Bone loss was also associated with the incidence of AD (OR=1.81 95% CI 1.28, 2.55)., Conclusions: Overall, the results support the hypothesis that depression is associated with subsequent cognitive decline. Bone loss was also found to be associated with AD incidence; however, due to the small number of studies, the results should be viewed with caution., (Copyright © 2022. Published by Elsevier B.V.)
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- 2022
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16. Frailty associations with socioeconomic status, healthcare utilisation and quality of life among older women residing in regional Australia.
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Yong SJ, Gwini SM, Tembo MC, Ng BL, Low CH, Malon RG, Dunning TL, Pasco JA, and Kotowicz MA
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Objectives: The health and well-being of older women may be influenced by frailty and low socioeconomic status (SES). This study examined the association between frailty and SES, healthcare utilisation and quality of life (QOL) among older women in regional Australia., Methods: Cross-sectional analysis of the Geelong Osteoporosis Study was conducted on 360 women (ages ≥60yr) in the 15-year follow up. Frailty was identified using modified Fried's phenotype. Individual SES measures and healthcare utilisation were documented by questionnaire. Area-based SES was determined by cross-referencing residential addresses with the Australian Bureau of Statistics Index of Relative Socio-economic Advantage and Disadvantage (IRSAD). QOL was measured using the Australian World Health Organisation Quality of Life Instrument (WHOQoL-Bref). Multinomial logistic regression was conducted with frailty groupings as outcome., Results: Sixty-two (17.2%) participants were frail, 199 (55.3%) pre-frail and 99 (27.5%) robust. Frail participants were older with higher body mass index. Frailty was associated with lower education but not marital status, occupation or IRSAD. Strong associations with frailty were demonstrated for all WHOQoL-Bref domains. Frailty was associated with more primary care doctor visits (p<0.001)., Conclusions: This population-based study highlights the significant impact of frailty on older women, indicating reduced QOL and increased primary care doctor visits., (Copyright: © 2021 Hylonome Publications.)
- Published
- 2021
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17. Hi-C scaffolded short- and long-read genome assemblies of the California sea lion are broadly consistent for syntenic inference across 45 million years of evolution.
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Peart CR, Williams C, Pophaly SD, Neely BA, Gulland FMD, Adams DJ, Ng BL, Cheng W, Goebel ME, Fedrigo O, Haase B, Mountcastle J, Fungtammasan A, Formenti G, Collins J, Wood J, Sims Y, Torrance J, Tracey A, Howe K, Rhie A, Hoffman JI, Johnson J, Jarvis ED, Breen M, and Wolf JBW
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- Animals, Dogs, Ferrets, Genome, Synteny, X Chromosome, Sea Lions genetics
- Abstract
With the advent of chromatin-interaction maps, chromosome-level genome assemblies have become a reality for a wide range of organisms. Scaffolding quality is, however, difficult to judge. To explore this gap, we generated multiple chromosome-scale genome assemblies of an emerging wild animal model for carcinogenesis, the California sea lion (Zalophus californianus). Short-read assemblies were scaffolded with two independent chromatin interaction mapping data sets (Hi-C and Chicago), and long-read assemblies with three data types (Hi-C, optical maps and 10X linked reads) following the "Vertebrate Genomes Project (VGP)" pipeline. In both approaches, 18 major scaffolds recovered the karyotype (2n = 36), with scaffold N50s of 138 and 147 Mb, respectively. Synteny relationships at the chromosome level with other pinniped genomes (2n = 32-36), ferret (2n = 34), red panda (2n = 36) and domestic dog (2n = 78) were consistent across approaches and recovered known fissions and fusions. Comparative chromosome painting and multicolour chromosome tiling with a panel of 264 genome-integrated single-locus canine bacterial artificial chromosome probes provided independent evaluation of genome organization. Broad-scale discrepancies between the approaches were observed within chromosomes, most commonly in translocations centred around centromeres and telomeres, which were better resolved in the VGP assembly. Genomic and cytological approaches agreed on near-perfect synteny of the X chromosome, and in combination allowed detailed investigation of autosomal rearrangements between dog and sea lion. This study presents high-quality genomes of an emerging cancer model and highlights that even highly fragmented short-read assemblies scaffolded with Hi-C can yield reliable chromosome-level scaffolds suitable for comparative genomic analyses., (© 2021 The Authors. Molecular Ecology Resources published by John Wiley & Sons Ltd.)
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- 2021
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18. Simvastatin enhances the efficacy of nilotinib in chronic myeloid leukaemia by post-translational modification and drug transporter modulation.
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Asari K, Sun WT, Kok ZH, Lam YH, Ng BL, Saunders V, White DL, Chuah C, and Xiang W
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- Animals, Antineoplastic Agents administration & dosage, Apoptosis drug effects, Cell Line, Tumor, Cell Proliferation drug effects, Drug Combinations, Drug Resistance, Neoplasm physiology, Mice, Protein-Tyrosine Kinases antagonists & inhibitors, Pyrimidines administration & dosage, Pyrimidines pharmacokinetics, Simvastatin administration & dosage, Antineoplastic Agents pharmacology, Leukemia, Myelogenous, Chronic, BCR-ABL Positive drug therapy, Pyrimidines pharmacology, Simvastatin pharmacology
- Abstract
The resistance of chronic myeloid leukaemia (CML) to tyrosine kinase inhibitors (TKIs) remains a significant clinical problem. Targeting alternative pathways, such as protein prenylation, is known to be effective in overcoming resistance. Simvastatin inhibits 3-hydroxy-3-methylglutaryl-CoA reductase (a key enzyme in isoprenoid-regulation), thereby inhibiting prenylation. We demonstrate that simvastatin alone effectively inhibits proliferation in a panel of TKI-resistant CML cell lines, regardless of mechanism of resistance. We further show that the combination of nilotinib and simvastatin synergistically kills CML cells via an increase in apoptosis and decrease in prosurvival proteins and cellular proliferation. Mechanistically, simvastatin inhibits protein prenylation as shown by increased levels of unprenylated Ras and rescue experiments with mevalonate resulted in abrogation of synergism. The combination also leads to an increase in the intracellular uptake and retention of radio-labelled nilotinib, which further enhances the inhibition of Bcr-Abl kinase activity. In primary CML samples, this combination inhibits clonogenicity in both imatinib-naive and resistant cells. Such combinatorial effects provide the basis for utilising these Food and Drug Administration-approved drugs as a potential clinical approach in overcoming resistance and improving CML treatment., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)
- Published
- 2021
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19. Single-cell atlas of the first intra-mammalian developmental stage of the human parasite Schistosoma mansoni.
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Diaz Soria CL, Lee J, Chong T, Coghlan A, Tracey A, Young MD, Andrews T, Hall C, Ng BL, Rawlinson K, Doyle SR, Leonard S, Lu Z, Bennett HM, Rinaldi G, Newmark PA, and Berriman M
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- Animals, Esophagus metabolism, Exons genetics, Gene Expression Regulation, Humans, Muscle Cells metabolism, Nervous System cytology, Neurons cytology, Parasites genetics, Schistosoma mansoni genetics, Stem Cells cytology, Stem Cells metabolism, Transcription, Genetic, Mammals parasitology, Parasites cytology, Parasites growth & development, Schistosoma mansoni cytology, Schistosoma mansoni growth & development, Single-Cell Analysis
- Abstract
Over 250 million people suffer from schistosomiasis, a tropical disease caused by parasitic flatworms known as schistosomes. Humans become infected by free-swimming, water-borne larvae, which penetrate the skin. The earliest intra-mammalian stage, called the schistosomulum, undergoes a series of developmental transitions. These changes are critical for the parasite to adapt to its new environment as it navigates through host tissues to reach its niche, where it will grow to reproductive maturity. Unravelling the mechanisms that drive intra-mammalian development requires knowledge of the spatial organisation and transcriptional dynamics of different cell types that comprise the schistomulum body. To fill these important knowledge gaps, we perform single-cell RNA sequencing on two-day old schistosomula of Schistosoma mansoni. We identify likely gene expression profiles for muscle, nervous system, tegument, oesophageal gland, parenchymal/primordial gut cells, and stem cells. In addition, we validate cell markers for all these clusters by in situ hybridisation in schistosomula and adult parasites. Taken together, this study provides a comprehensive cell-type atlas for the early intra-mammalian stage of this devastating metazoan parasite.
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- 2020
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20. Prevalence of Frailty in Older Men and Women: Cross-Sectional Data from the Geelong Osteoporosis Study.
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Tembo MC, Holloway-Kew KL, Sui SX, Dunning T, Low ACH, Yong SJ, Ng BL, Brennan-Olsen SL, Williams LJ, Kotowicz MA, and Pasco JA
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- Aged, Australia epidemiology, Cross-Sectional Studies, Female, Humans, Male, Prevalence, Frail Elderly, Frailty epidemiology
- Abstract
Few studies have investigated the prevalence of frailty in the Australian general population. This study determined the prevalence of frailty in a population-based sample of older adults and examined the relationship between frailty and comorbid conditions. Men (n = 347) and women (n = 360) aged ≥ 60 year from the Geelong Osteoporosis Study (GOS) were assessed between 2016-2019 and 2011-2014, respectively. Frailty was identified using a modified Fried frailty phenotype. Prevalence estimates were standardised to the 2011 Australian population. Kruskal-Wallis test and χ
2 test were used to analyse data. For women, mean standardised prevalence estimates were 18.3% (14.1-22.5) for frail, 54.1% (47.3-60.8) pre-frail and 22.9% (18.9-26.8) robust. Corresponding estimates for men were 13.1% (9.8-16.3) frail, 47.8% (42.0-53.6) pre-frail and 27.3% (22.7-31.8) robust. Women who were frail were older, shorter, tended to have a higher body mass index (BMI) and used more medications compared to other groups. Compared to robust women, those who were frail were more likely to have cardio-metabolic (OR 3.5 (0.7-20.0)), pulmonary (OR 3.5 (1.5-8.4)) and musculoskeletal (OR 10.1 (2.1-48.0)) conditions. Frail men were older, had a higher BMI and were more likely to have musculoskeletal conditions (OR 5.8 (2.8-12.3)) and tended to be from a lower SES. No further associations were observed. This study reported the prevalence of frail and pre-frail individuals in a population-based sample of Australian men and women. Frailty was associated with musculoskeletal conditions for both men and women; however, associations with cardio-metabolic and pulmonary comorbidities were evident in women only.- Published
- 2020
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21. Identifying proteins bound to native mitotic ESC chromosomes reveals chromatin repressors are important for compaction.
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Djeghloul D, Patel B, Kramer H, Dimond A, Whilding C, Brown K, Kohler AC, Feytout A, Veland N, Elliott J, Bharat TAM, Tarafder AK, Löwe J, Ng BL, Guo Y, Guy J, Huseyin MK, Klose RJ, Merkenschlager M, and Fisher AG
- Subjects
- Animals, DNA (Cytosine-5-)-Methyltransferase 1 metabolism, DNA (Cytosine-5-)-Methyltransferases metabolism, DNA Methylation genetics, DNA Methylation physiology, DNA Methyltransferase 3A, Fluorescent Antibody Technique, Methyl-CpG-Binding Protein 2 metabolism, Mice, Proteomics, DNA Methyltransferase 3B, Chromatin metabolism, Chromosomes metabolism, Embryonic Stem Cells metabolism, Transcription Factors metabolism
- Abstract
Epigenetic information is transmitted from mother to daughter cells through mitosis. Here, to identify factors that might play a role in conveying epigenetic memory through cell division, we report on the isolation of unfixed, native chromosomes from metaphase-arrested cells using flow cytometry and perform LC-MS/MS to identify chromosome-bound proteins. A quantitative proteomic comparison between metaphase-arrested cell lysates and chromosome-sorted samples reveals a cohort of proteins that were significantly enriched on mitotic ESC chromosomes. These include pluripotency-associated transcription factors, repressive chromatin-modifiers such as PRC2 and DNA methyl-transferases, and proteins governing chromosome architecture. Deletion of PRC2, Dnmt1/3a/3b or Mecp2 in ESCs leads to an increase in the size of individual mitotic chromosomes, consistent with de-condensation. Similar results were obtained by the experimental cleavage of cohesin. Thus, we identify chromosome-bound factors in pluripotent stem cells during mitosis and reveal that PRC2, DNA methylation and Mecp2 are required to maintain chromosome compaction.
- Published
- 2020
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22. Chromosome-level genome assembly for giant panda provides novel insights into Carnivora chromosome evolution.
- Author
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Fan H, Wu Q, Wei F, Yang F, Ng BL, and Hu Y
- Subjects
- Animals, Male, Synteny, Biological Evolution, Chromosomes, Genome, Ursidae genetics
- Abstract
Background: Chromosome evolution is an important driver of speciation and species evolution. Previous studies have detected chromosome rearrangement events among different Carnivora species using chromosome painting strategies. However, few of these studies have focused on chromosome evolution at a nucleotide resolution due to the limited availability of chromosome-level Carnivora genomes. Although the de novo genome assembly of the giant panda is available, current short read-based assemblies are limited to moderately sized scaffolds, making the study of chromosome evolution difficult., Results: Here, we present a chromosome-level giant panda draft genome with a total size of 2.29 Gb. Based on the giant panda genome and published chromosome-level dog and cat genomes, we conduct six large-scale pairwise synteny alignments and identify evolutionary breakpoint regions. Interestingly, gene functional enrichment analysis shows that for all of the three Carnivora genomes, some genes located in evolutionary breakpoint regions are significantly enriched in pathways or terms related to sensory perception of smell. In addition, we find that the sweet receptor gene TAS1R2, which has been proven to be a pseudogene in the cat genome, is located in an evolutionary breakpoint region of the giant panda, suggesting that interchromosomal rearrangement may play a role in the cat TAS1R2 pseudogenization., Conclusions: We show that the combined strategies employed in this study can be used to generate efficient chromosome-level genome assemblies. Moreover, our comparative genomics analyses provide novel insights into Carnivora chromosome evolution, linking chromosome evolution to functional gene evolution.
- Published
- 2019
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23. Disruption of chromatin organisation causes MEF2C gene overexpression in intellectual disability: a case report.
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Yauy K, Schneider A, Ng BL, Gaillard JB, Sati S, Coubes C, Wells C, Tournaire M, Guignard T, Bouret P, Geneviève D, Puechberty J, Pellestor F, and Gatinois V
- Subjects
- Child, Child, Preschool, Chromosome Banding, Chromosomes, Human, Pair 3 genetics, Chromosomes, Human, Pair 5 genetics, Female, Gene Duplication, Humans, Infant, Infant, Newborn, MEF2 Transcription Factors genetics, Chromatin metabolism, Intellectual Disability genetics
- Abstract
Background: Balanced structural variants are mostly described in disease with gene disruption or subtle rearrangement at breakpoints., Case Presentation: Here we report a patient with mild intellectual deficiency who carries a de novo balanced translocation t(3;5). Breakpoints were fully explored by microarray, Array Painting and Sanger sequencing. No gene disruption was found but the chromosome 5 breakpoint was localized 228-kb upstream of the MEF2C gene. The predicted Topologically Associated Domains analysis shows that it contains only the MEF2C gene and a long non-coding RNA LINC01226. RNA studies looking for MEF2C gene expression revealed an overexpression of MEF2C in the lymphoblastoid cell line of the patient., Conclusions: Pathogenicity of MEF2C overexpression is still unclear as only four patients with mild intellectual deficiency carrying 5q14.3 microduplications containing MEF2C are described in the literature. The microduplications in these individuals also contain other genes expressed in the brain. The patient presented the same phenotype as 5q14.3 microduplication patients. We report the first case of a balanced translocation leading to an overexpression of MEF2C similar to a functional duplication.
- Published
- 2019
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24. Derivation and maintenance of mouse haploid embryonic stem cells.
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Elling U, Woods M, Forment JV, Fu B, Yang F, Ng BL, Vicente JR, Adams DJ, Doe B, Jackson SP, Penninger JM, and Balmus G
- Subjects
- Animals, Blastocyst cytology, Cell Line, Cell Separation methods, Female, Mice, Mice, Inbred C57BL, Mice, Inbred Strains, Workflow, Cell Culture Techniques methods, Haploidy, Mouse Embryonic Stem Cells cytology, Mouse Embryonic Stem Cells physiology
- Abstract
Ploidy represents the number of chromosome sets in a cell. Although gametes have a haploid genome (n), most mammalian cells have diploid genomes (2n). The diploid status of most cells correlates with the number of probable alleles for each autosomal gene and makes it difficult to target these genes via mutagenesis techniques. Here, we describe a 7-week protocol for the derivation of mouse haploid embryonic stem cells (hESCs) from female gametes that also outlines how to maintain the cells once derived. We detail additional procedures that can be used with cell lines obtained from the mouse Haplobank, a biobank of >100,000 individual mouse hESC lines with targeted mutations in 16,970 genes. hESCs can spontaneously diploidize and can be maintained in both haploid and diploid states. Mouse hESCs are genomically and karyotypically stable, are innately immortal and isogenic, and can be derived in an array of differentiated cell types; they are thus highly amenable to genetic screens and to defining molecular connectivity pathways.
- Published
- 2019
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25. Automating the Shared Resource Laboratory Using Computer Scripts: A Case Report.
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Hall C, Brown L, Graham J, Thompson S, and Ng BL
- Subjects
- Software, Flow Cytometry standards, Laboratories standards
- Abstract
Shared resource laboratories (SRLs) offer instrumentation, training, and support to investigators and play an important role in the progress and development of science. To facilitate daily tasks and to provide an effective service, we have made use of computer scripts; a list of computer commands that are processed sequentially, to automate tasks in our flow cytometry facility. Using Python and an application programming interface (API), we automate user communication and produce a daily schedule display screen. We exploit the accessible nature of open standards to use R and Python to analyze and backup data from the BD Influx cell sorter. Finally, we show that through simple scripting, we can add value to an existing service by producing sort statistics from the Beckman Coulter XDP cell sorter. With these five examples, we demonstrate and wish to inspire other SRLs that the use of scripts helps to improve work efficiency, can solve problems, and can enhance the service provided by the SRL. © 2019 The Authors. Cytometry Part A published by Wiley Periodicals, Inc. on behalf of International Society for Advancement of Cytometry., (© 2019 The Authors. Cytometry Part A published by Wiley Periodicals, Inc. on behalf of International Society for Advancement of Cytometry.)
- Published
- 2019
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26. Characterizing Mutational Signatures in Human Cancer Cell Lines Reveals Episodic APOBEC Mutagenesis.
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Petljak M, Alexandrov LB, Brammeld JS, Price S, Wedge DC, Grossmann S, Dawson KJ, Ju YS, Iorio F, Tubio JMC, Koh CC, Georgakopoulos-Soares I, Rodríguez-Martín B, Otlu B, O'Meara S, Butler AP, Menzies A, Bhosle SG, Raine K, Jones DR, Teague JW, Beal K, Latimer C, O'Neill L, Zamora J, Anderson E, Patel N, Maddison M, Ng BL, Graham J, Garnett MJ, McDermott U, Nik-Zainal S, Campbell PJ, and Stratton MR
- Subjects
- APOBEC Deaminases metabolism, Cell Line, Cell Line, Tumor, DNA metabolism, DNA Mutational Analysis methods, Databases, Genetic, Exome, Genome, Human genetics, Heterografts, Humans, Mutagenesis, Mutation genetics, Mutation Rate, Retroelements, Exome Sequencing methods, APOBEC Deaminases genetics, Neoplasms genetics
- Abstract
Multiple signatures of somatic mutations have been identified in cancer genomes. Exome sequences of 1,001 human cancer cell lines and 577 xenografts revealed most common mutational signatures, indicating past activity of the underlying processes, usually in appropriate cancer types. To investigate ongoing patterns of mutational-signature generation, cell lines were cultured for extended periods and subsequently DNA sequenced. Signatures of discontinued exposures, including tobacco smoke and ultraviolet light, were not generated in vitro. Signatures of normal and defective DNA repair and replication continued to be generated at roughly stable mutation rates. Signatures of APOBEC cytidine deaminase DNA-editing exhibited substantial fluctuations in mutation rate over time with episodic bursts of mutations. The initiating factors for the bursts are unclear, although retrotransposon mobilization may contribute. The examined cell lines constitute a resource of live experimental models of mutational processes, which potentially retain patterns of activity and regulation operative in primary human cancers., (Crown Copyright © 2019. Published by Elsevier Inc. All rights reserved.)
- Published
- 2019
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27. Chromosome Analysis Using Benchtop Flow Analysers and High Speed Cell Sorters.
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Ng BL, Fu B, Graham J, Hall C, and Thompson S
- Subjects
- Cell Line, DNA chemistry, Fluorescence, Fluorescent Dyes chemistry, Humans, Lasers, Male, Propidium, Chromosomes chemistry, DNA analysis, Flow Cytometry methods, Karyotyping methods
- Abstract
The use of the DNA dyes Hoechst (HO) and chromomycin A3 (CA3) has become the preferred combination for the bivariate analysis of chromosomes from both human and animals. This analysis requires a flow cytometer equipped with lasers of specific wavelength and of higher power than is typical on a conventional bench top flow cytometer. In this study, we have investigated the resolution of chromosome peaks in a human cell line with normal flow karyotype using different combinations of DNA dyes on a number of flow cytometers available in a flow cytometry core facility. Chromosomes were prepared from the human cell line using a modified polyamine isolation buffer. The bivariate flow karyotypes of different DNA dyes combination; 4'-6-diamidino-2-phenylindole (DAPI) or Hoechst with propidium iodide (PI), obtained from different flow cytometers were compared to the reference flow karyotype of DAPI or Hoechst with chromomycin A3, generated from a Mo-Flo cell sorter using laser power settings of 300 mW each of UV and 457 nm. Good chromosome separation was observed in most of the flow cytometers used in the study. This study demonstrates that chromosome analysis and sorting can also be performed on benchtop flow cytometers equipped with the standard solid state 488 and 355 nm lasers, using a DNA dye combination of DAPI or Hoechst with PI. © 2018 The Authors. Cytometry Part A published by Wiley Periodicals, Inc. on behalf of International Society for Advancement of Cytometry., (© 2018 The Authors. Cytometry Part A published by Wiley Periodicals, Inc. on behalf of International Society for Advancement of Cytometry.)
- Published
- 2019
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28. Relationship Between Sequence Homology, Genome Architecture, and Meiotic Behavior of the Sex Chromosomes in North American Voles.
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Dumont BL, Williams CL, Ng BL, Horncastle V, Chambers CL, McGraw LA, Adams D, Mackay TFC, and Breen M
- Subjects
- Animals, Genomics methods, Meiosis genetics, North America, Pseudoautosomal Regions genetics, Sequence Analysis, DNA methods, Sequence Homology, Nucleic Acid, Telomere genetics, Telomere-Binding Proteins genetics, X Chromosome genetics, Y Chromosome genetics, Arvicolinae genetics, Chromosome Segregation genetics, Sex Chromosomes genetics
- Abstract
In most mammals, the X and Y chromosomes synapse and recombine along a conserved region of homology known as the pseudoautosomal region (PAR). These homology-driven interactions are required for meiotic progression and are essential for male fertility. Although the PAR fulfills key meiotic functions in most mammals, several exceptional species lack PAR-mediated sex chromosome associations at meiosis. Here, we leveraged the natural variation in meiotic sex chromosome programs present in North American voles ( Microtus ) to investigate the relationship between meiotic sex chromosome dynamics and X/Y sequence homology. To this end, we developed a novel, reference-blind computational method to analyze sparse sequencing data from flow-sorted X and Y chromosomes isolated from vole species with sex chromosomes that always ( Microtus montanus ), never ( Microtus mogollonensis ), and occasionally synapse ( Microtus ochrogaster ) at meiosis. Unexpectedly, we find more shared X/Y homology in the two vole species with no and sporadic X/Y synapsis compared to the species with obligate synapsis. Sex chromosome homology in the asynaptic and occasionally synaptic species is interspersed along chromosomes and largely restricted to low-complexity sequences, including a striking enrichment for the telomeric repeat sequence, TTAGGG. In contrast, homology is concentrated in high complexity, and presumably euchromatic, sequence on the X and Y chromosomes of the synaptic vole species, M. montanus Taken together, our findings suggest key conditions required to sustain the standard program of X/Y synapsis at meiosis and reveal an intriguing connection between heterochromatic repeat architecture and noncanonical, asynaptic mechanisms of sex chromosome segregation in voles., (Copyright © 2018 by the Genetics Society of America.)
- Published
- 2018
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29. Clinical utility of MRI and SPECT in the diagnosis of cognitive impairment referred to memory clinic.
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Guinane J and Ng BL
- Subjects
- Aged, Aged, 80 and over, Female, Humans, Male, Memory, Middle Aged, Neuropsychological Tests, Predictive Value of Tests, Risk Factors, Cognitive Dysfunction diagnostic imaging, Dementia diagnostic imaging, Magnetic Resonance Imaging, Tomography, Emission-Computed, Single-Photon
- Abstract
ABSTRACTBackground:Despite of their limited availability and potential for significant variation between and within each modality, this is the first study to prospectively measure the clinical utility of MRI and/or SPECT brain scanning in addition to the routine diagnostic workup of patients presenting to memory clinic., Methods: A single center study was conducted over a convenience of 12-month sampling period. For each patient referred for MRI and/or SPECT scanning, the primary geriatrician or psychogeriatrician was asked to assign an initial diagnosis. The initial diagnosis was then compared with the final consensus diagnosis after any scans or neuropsychology testing had been completed., Results: During the 12-month study period, 66 patients (26%) were referred for scans out of a total of 253 patients included in the study. There were 16/44 (36%) positive MRI outcomes and 13/35 (37%) positive SPECT outcomes. The diagnosis changed consistent with the MRI scan findings in 11/44 (25%) and changed consistent with the SPECT scan findings in 9/35 (26%). Potentially reversible pathology was identified in a single patient, 1/50 (2%), via an MRI scan that suggested normal pressure hydrocephalus. The number needed to test for one positive outcome was 3.8 (95% CI 2.0-23.3), 6.0 (95% CI NA), and 1.7 (95% CI 1.3-2.5) for MRI only, SPECT only, and MRI and SPECT together, respectively., Conclusions: The clinical utility of MRI and/or SPECT scanning in this study may be broadly superior to the available international evidence, and further research is needed to identify predictors of positive scan outcomes.
- Published
- 2018
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30. Chromosomal breaks at FRA18C: association with reduced DOK6 expression, altered oncogenic signaling and increased gastric cancer survival.
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Leong SH, Lwin KM, Lee SS, Ng WH, Ng KM, Tan SY, Ng BL, Carter NP, Tang C, and Lian Kon O
- Abstract
Chromosomal rearrangements are common in cancer. More than 50% occur in common fragile sites and disrupt tumor suppressors. However, such rearrangements are not known in gastric cancer. Here we report recurrent 18q2 breakpoints in 6 of 17 gastric cancer cell lines. The rearranged chromosome 18, t(9;18), in MKN7 cells was flow sorted and identified by reverse chromosome painting. High-resolution tiling array hybridization mapped breakpoints to DOK6 (docking protein 6) intron 4 in FRA18C (18q22.2) and an intergenic region in 9q22.2. The same rearrangement was detected by FISH in 22% of 99 primary gastric cancers. Intron 4 truncation was associated with reduced DOK6 transcription. Analysis of The Cancer Genome Atlas stomach adenocarcinoma cohort showed significant correlation of DOK6 expression with histological and molecular phenotypes. Multiple oncogenic signaling pathways (gastrin-CREB, NGF-neurotrophin, PDGF, EGFR, ERK, ERBB4, FGFR1, RAS, VEGFR2 and RAF/MAP kinase) known to be active in aggressive gastric cancers were strikingly diminished in gastric cancers with low DOK6 expression. Median survival of patients with low DOK6 -expressing tumors was 2100 days compared with 533 days in patients with high DOK6 -expressing tumors (log-rank P = 0.0027). The level of DOK6 expression in tumors predicted patient survival independent of TNM stage. These findings point to new functions of human DOK6 as an adaptor that interacts with diverse molecular components of signaling pathways. Our data suggest that DOK6 expression is an integrated biomarker of multiple oncogenic signals in gastric cancer and identify FRA18C as a new cancer-associated fragile site., Competing Interests: The authors declare no competing financial interests.
- Published
- 2017
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31. New insights into sex chromosome evolution in anole lizards (Reptilia, Dactyloidae).
- Author
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Giovannotti M, Trifonov VA, Paoletti A, Kichigin IG, O'Brien PC, Kasai F, Giovagnoli G, Ng BL, Ruggeri P, Cerioni PN, Splendiani A, Pereira JC, Olmo E, Rens W, Caputo Barucchi V, and Ferguson-Smith MA
- Subjects
- Animals, Chromosome Banding, Chromosome Mapping, Chromosome Painting, Female, Genes, Mitochondrial, In Situ Hybridization, Fluorescence, Karyotype, Karyotyping, Male, Recombination, Genetic, Evolution, Molecular, Lizards genetics, Sex Chromosomes
- Abstract
Anoles are a clade of iguanian lizards that underwent an extensive radiation between 125 and 65 million years ago. Their karyotypes show wide variation in diploid number spanning from 26 (Anolis evermanni) to 44 (A. insolitus). This chromosomal variation involves their sex chromosomes, ranging from simple systems (XX/XY), with heterochromosomes represented by either micro- or macrochromosomes, to multiple systems (X
1 X1 X2 X2 /X1 X2 Y). Here, for the first time, the homology relationships of sex chromosomes have been investigated in nine anole lizards at the whole chromosome level. Cross-species chromosome painting using sex chromosome paints from A. carolinensis, Ctenonotus pogus and Norops sagrei and gene mapping of X-linked genes demonstrated that the anole ancestral sex chromosome system constituted by microchromosomes is retained in all the species with the ancestral karyotype (2n = 36, 12 macro- and 24 microchromosomes). On the contrary, species with a derived karyotype, namely those belonging to genera Ctenonotus and Norops, show a series of rearrangements (fusions/fissions) involving autosomes/microchromosomes that led to the formation of their current sex chromosome systems. These results demonstrate that different autosomes were involved in translocations with sex chromosomes in closely related lineages of anole lizards and that several sequential microautosome/sex chromosome fusions lead to a remarkable increase in size of Norops sagrei sex chromosomes.- Published
- 2017
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32. Evolutionary dynamics of Anolis sex chromosomes revealed by sequencing of flow sorting-derived microchromosome-specific DNA.
- Author
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Kichigin IG, Giovannotti M, Makunin AI, Ng BL, Kabilov MR, Tupikin AE, Barucchi VC, Splendiani A, Ruggeri P, Rens W, O'Brien PC, Ferguson-Smith MA, Graphodatsky AS, and Trifonov VA
- Subjects
- Animals, Chromosome Mapping, DNA isolation & purification, Evolution, Molecular, Microdissection, High-Throughput Nucleotide Sequencing methods, Reptiles genetics, Sequence Analysis, DNA methods, Sex Chromosomes genetics
- Abstract
Squamate reptiles show a striking diversity in modes of sex determination, including both genetic (XY or ZW) and temperature-dependent sex determination systems. The genomes of only a handful of species have been sequenced, analyzed and assembled including the genome of Anolis carolinensis. Despite a high genome coverage, only macrochromosomes of A. carolinensis were assembled whereas the content of most microchromosomes remained unclear. Most of the Anolis species have homomorphic XY sex chromosome system. However, some species have large heteromorphic XY chromosomes (e.g., A. sagrei) and even multiple sex chromosomes systems (e.g. A. pogus), that were shown to be derived from fusions of the ancestral XY with microautosomes. We applied next generation sequencing of flow sorting-derived chromosome-specific DNA pools to characterize the content and composition of microchromosomes in A. carolinensis and A. sagrei. Comparative analysis of sequenced chromosome-specific DNA pools revealed that the A. sagrei XY sex chromosomes contain regions homologous to several microautosomes of A. carolinensis. We suggest that the sex chromosomes of A. sagrei are derived by fusions of the ancestral sex chromosome with three microautosomes and subsequent loss of some genetic content on the Y chromosome.
- Published
- 2016
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33. Inhibition of isoprenylcysteine carboxylmethyltransferase augments BCR-ABL1 tyrosine kinase inhibition-induced apoptosis in chronic myeloid leukemia.
- Author
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Sun WT, Xiang W, Ng BL, Asari K, Bunte RM, Casey PJ, Wang M, and Chuah C
- Subjects
- Animals, Female, Fusion Proteins, bcr-abl genetics, Fusion Proteins, bcr-abl metabolism, Humans, Leukemia, Myelogenous, Chronic, BCR-ABL Positive enzymology, Leukemia, Myelogenous, Chronic, BCR-ABL Positive genetics, Leukemia, Myelogenous, Chronic, BCR-ABL Positive pathology, MAP Kinase Signaling System drug effects, MAP Kinase Signaling System genetics, Male, Mice, Neoplastic Stem Cells enzymology, Neoplastic Stem Cells pathology, Protein Methyltransferases genetics, Protein Methyltransferases metabolism, Apoptosis drug effects, Fusion Proteins, bcr-abl antagonists & inhibitors, Imatinib Mesylate pharmacology, Indoles pharmacology, Leukemia, Myelogenous, Chronic, BCR-ABL Positive drug therapy, Protein Methyltransferases antagonists & inhibitors
- Abstract
Despite the success of BCR-ABL1 tyrosine kinase inhibitors in patients with chronic myeloid leukemia (CML), resistance to tyrosine kinase inhibitors remains a therapeutic challenge. One strategy used to overcome resistance is combination of existing BCR-ABL1 tyrosine kinase inhibitors with agents that target alternative pathways. We report that inhibition of isoprenylcysteine carboxylmethyltransferase (Icmt), a key enzyme in the protein prenylation pathway, with the selective inhibitor cysmethynil enhances the effect of BCR-ABL1 tyrosine kinase inhibitors in killing CML cells. Cysmethynil augments tyrosine kinase inhibitor-induced apoptosis in both BCR-ABL1 wild type and BCR-ABL1 kinase domain mutant-expressing cell lines. Importantly, the enhanced apoptosis observed with the combination of cysmethynil and imatinib is significant only in primary CML CD34+ progenitor cells, not normal cord blood progenitor cells. The combination was also selective in inhibiting colony formation in CML CD34+ cells. The enhanced apoptosis appears to be due to combination of immediate and persistent inhibition of MAPK signaling. Consistent with in vitro studies, cysmethynil and imatinib, in combination, enhance the in vivo effects of either drug used alone. We found that simultaneous inhibition of BCR-ABL1 and Icmt may represent a potential therapeutic strategy for CML., (Copyright © 2016 ISEH - International Society for Experimental Hematology. Published by Elsevier Inc. All rights reserved.)
- Published
- 2016
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34. Dynamic Changes of Pulmonary Arterial Pressure and Ductus Arteriosus in Human Newborns From Birth to 72 Hours of Age.
- Author
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Kang C, Zhao E, Zhou Y, Zhao H, Liu Y, Gao N, Huang X, and Liu B
- Subjects
- Echocardiography, Female, Humans, Male, Prospective Studies, Time Factors, Arterial Pressure physiology, Ductus Arteriosus physiopathology, Infant, Newborn physiology, Pulmonary Artery physiology
- Abstract
Normal pulmonary artery pressure and pulmonary hypertension assessment of newborns is rarely reported. The aim of the study is to explore dynamic changes of pulmonary arterial pressure and ductus arteriosus in human newborns from birth to 72 h of age with echocardiography.A total of 76 cases of normal newborns were prospectively detected by echocardiography after birth of 2 h, 6 h, 12 h, 24 h, 48 h, and 72 h, respectively. Ductus arteriosus diameter, blood shunt direction, blood flow velocity, and pressure gradient were recorded. The brachial artery blood pressure were measured to estimate the pulmonary artery systolic pressure (PASP) and pulmonary artery diastolic pressure (PADP) using patent ductus arteriosus pressure gradient method. The mean pulmonary artery pressure (PAMP) were calculated by equation of PAMP = PADP + 1/3(PASP-PADP).(1) There were 76 cases of normal newborns. Among them, 29 cases (38%) ductus arteriosus closed within 24 h, 59 cases (78%) closed within 48 h, 72 cases (95%) closed within 72 h, and 4 cases (5%) ductus arteriosus not closed within 72 h. (2) The ductus arteriosus diameter of 2 h, 6 h, 12 h, 24 h, 48 h, and 72 h after birth was 4.60 ± 0.59 mm, 3.37 ± 0.59 mm, 2.47 ± 0.49 mm, 1.89 ± 0.41 mm, 1.61 ± 0.35 mm, and 1.20 ± 0.24 mm, respectively. Compared all of the ductus arteriosus diameter of the above time periods, there were statistically differences with P < 0.05, respectively. (3) The mean PASP in 2 h, 6 h, 12 h, 24 h, 48 h, 72 h after birth were 76.58 ± 7.28 mm Hg, 65.53 ± 9.25mm Hg, 52.51 ± 9.07 mm Hg, 43.83 ± 7.90 mm Hg, 38.07 ± 8.26 mm Hg, and 36 ± 6.48 mm Hg, respectively. The PADP of the above time period were 37.88 ± 5.56 mm Hg, 29.93 ± 7.91 mm Hg, 23.43 ± 7.37 mm Hg, 19.70 ± 8.51 mm Hg, 13.85 ± 5.58 mm Hg, 13.25 ± 6.18 mm Hg, respectively. The PAMP of the above time period were 63.41 ± 7.03 mm Hg, 51.78 ± 9.82 mm Hg, 40.94 ± 9.32 mm Hg, 34.39 ± 9.89 mm Hg, 26.23 ± 7.49 mm Hg, 25.25 ± 8.29 mm Hg, respectively. There were statistically differences with P < 0.05 between each time periods of PASP, PADP, and PAMP. (4) The upper 95% limit reference range of PASP of normal newborns of 72 h after birth were 39.97 mm Hg.(1) Normal newborns ductus arteriosus diameter gradually decreased after birth, and 95% of them spontaneous closed within 24 to 72 h. (2) Normal newborns pulmonary artery pressure showed a gradually decline after birth, the upper 95% limit reference range for PASP measured in normal newborns <72 h of age was 39.97 mm Hg. Therefore, the diagnostic criteria of newborns pulmonary hypertension may be >40.00 mm Hg according to our limited study., Competing Interests: The authors have no funding and conflicts of interest to disclose.
- Published
- 2016
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35. The pig X and Y Chromosomes: structure, sequence, and evolution.
- Author
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Skinner BM, Sargent CA, Churcher C, Hunt T, Herrero J, Loveland JE, Dunn M, Louzada S, Fu B, Chow W, Gilbert J, Austin-Guest S, Beal K, Carvalho-Silva D, Cheng W, Gordon D, Grafham D, Hardy M, Harley J, Hauser H, Howden P, Howe K, Lachani K, Ellis PJ, Kelly D, Kerry G, Kerwin J, Ng BL, Threadgold G, Wileman T, Wood JM, Yang F, Harrow J, Affara NA, and Tyler-Smith C
- Subjects
- Animals, Base Sequence, Cats genetics, Dogs genetics, Female, Gene Conversion, Gene Expression, Gene Library, Gene Order, Humans, Male, Molecular Sequence Data, Sequence Alignment, Sequence Analysis, DNA, Chromosomes, Mammalian genetics, Evolution, Molecular, Swine genetics, X Chromosome genetics, Y Chromosome genetics
- Abstract
We have generated an improved assembly and gene annotation of the pig X Chromosome, and a first draft assembly of the pig Y Chromosome, by sequencing BAC and fosmid clones from Duroc animals and incorporating information from optical mapping and fiber-FISH. The X Chromosome carries 1033 annotated genes, 690 of which are protein coding. Gene order closely matches that found in primates (including humans) and carnivores (including cats and dogs), which is inferred to be ancestral. Nevertheless, several protein-coding genes present on the human X Chromosome were absent from the pig, and 38 pig-specific X-chromosomal genes were annotated, 22 of which were olfactory receptors. The pig Y-specific Chromosome sequence generated here comprises 30 megabases (Mb). A 15-Mb subset of this sequence was assembled, revealing two clusters of male-specific low copy number genes, separated by an ampliconic region including the HSFY gene family, which together make up most of the short arm. Both clusters contain palindromes with high sequence identity, presumably maintained by gene conversion. Many of the ancestral X-related genes previously reported in at least one mammalian Y Chromosome are represented either as active genes or partial sequences. This sequencing project has allowed us to identify genes--both single copy and amplified--on the pig Y Chromosome, to compare the pig X and Y Chromosomes for homologous sequences, and thereby to reveal mechanisms underlying pig X and Y Chromosome evolution., (© 2016 Skinner et al.; Published by Cold Spring Harbor Laboratory Press.)
- Published
- 2016
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36. Identification of disrupted AUTS2 and EPHA6 genes by array painting in a patient carrying a de novo balanced translocation t(3;7) with intellectual disability and neurodevelopment disorder.
- Author
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Schneider A, Puechberty J, Ng BL, Coubes C, Gatinois V, Tournaire M, Girard M, Dumont B, Bouret P, Magnetto J, Baghdadli A, Pellestor F, and Geneviève D
- Subjects
- Base Sequence, Child, Chromosome Painting methods, Chromosomes, Human, Pair 3, Chromosomes, Human, Pair 7, Cytoskeletal Proteins, Female, Humans, Male, Molecular Sequence Data, Pregnancy, Transcription Factors, Intellectual Disability genetics, Neurodevelopmental Disorders genetics, Proteins genetics, Receptor, EphA6 genetics, Translocation, Genetic
- Abstract
Intellectual disability (ID) is a frequent feature but is highly clinically and genetically heterogeneous. The establishment of the precise diagnosis in patients with ID is challenging due to this heterogeneity but crucial for genetic counseling and appropriate care for the patients. Among the etiologies of patients with ID, apparently balanced de novo rearrangements represent 0.6%. Several mechanisms explain the ID in patients with apparently balanced de novo rearrangement. Among them, disruption of a disease gene at the breakpoint, is frequently evoked. In this context, technologies recently developed are used to characterize precisely such chromosomal rearrangements. Here, we report the case of a boy with ID, facial features and autistic behavior who is carrying a de novo balanced reciprocal translocation t(3;7)(q11.2;q11.22)dn. Using microarray analysis, array painting (AP) technology combined with molecular study, we have identified the interruption of the autism susceptibility candidate 2 gene (AUTS2) and EPH receptor A6 gene (EPHA6). We consider that the disruption of AUTS2 explains the phenotype of the patient; the exact role of EPHA6 in human pathology is not well defined. Based on the observation of recurrent germinal and somatic translocations involving AUTS2 and the molecular environment content, we put forward the hypothesis that the likely chromosomal mechanism responsible for the translocation could be due either to replicative stress or to recombination-based mechanisms., (© 2015 Wiley Periodicals, Inc.)
- Published
- 2015
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37. Post-operative survival following metastasectomy for patients receiving BRAF inhibitor therapy is associated with duration of pre-operative treatment and elective indication.
- Author
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He M, Lovell J, Ng BL, Spillane J, Speakman D, Henderson MA, Shackleton M, and Gyorki DE
- Subjects
- Adult, Aged, Antineoplastic Agents therapeutic use, Female, Humans, Male, Melanoma secondary, Middle Aged, Retrospective Studies, Skin Neoplasms drug therapy, Skin Neoplasms pathology, Skin Neoplasms surgery, Survival Analysis, Vemurafenib, Young Adult, Indoles therapeutic use, Melanoma mortality, Melanoma therapy, Metastasectomy, Protein Kinase Inhibitors therapeutic use, Proto-Oncogene Proteins B-raf antagonists & inhibitors, Sulfonamides therapeutic use
- Abstract
Introduction: Metastasectomy can provide durable disease control for selected patients with metastatic melanoma. Vemurafenib is a BRAF kinase inhibitor which has demonstrated significant improvement in disease-specific survival in patients with metastatic melanoma with a BRAF gene mutation. This study examined the efficacy and safety of metastasectomy during treatment with vemurafenib., Methods: A retrospective review was performed of all patients receiving vemurafenib at Peter MacCallum Cancer Centre. Patient records were reviewed to identify patients undergoing surgery within 30 days of vemurafenib therapy. Descriptive statistics and survival analysis were performed., Results: Nineteen patients underwent 21 metastasectomies including craniotomy (57%), spinal decompression (14%), small bowel resection (14%), lung resection (9.5%) and neck dissection (4.5%). Indications for surgery were: an isolated residual focus of disease (n = 2); isolated progressive disease in the setting of stability elsewhere (n = 9); and symptomatic disease (n = 8). Grade 2 or higher surgical complications occurred in 19% of cases and there was one peri-operative death. Median post-operative survival was seven months. There was a trend toward improved post-operative survival for patients with longer duration of vemurafenib therapy (P = 0.04) and for those undergoing elective surgery (P = 0.07)., Conclusion: Resection of oligometastatic disease during BRAF-targeted therapy is safe. Selected patients have durable post-operative disease control., (© 2015 Wiley Periodicals, Inc.)
- Published
- 2015
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38. A First Generation Comparative Chromosome Map between Guinea Pig (Cavia porcellus) and Humans.
- Author
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Romanenko SA, Perelman PL, Trifonov VA, Serdyukova NA, Li T, Fu B, O'Brien PC, Ng BL, Nie W, Liehr T, Stanyon R, Graphodatsky AS, and Yang F
- Subjects
- Animals, Guinea Pigs, Humans, Species Specificity, Chromosome Mapping, Chromosome Painting, Chromosomes, Human genetics, Evolution, Molecular, Genome, Human
- Abstract
The domesticated guinea pig, Cavia porcellus (Hystricomorpha, Rodentia), is an important laboratory species and a model for a number of human diseases. Nevertheless, genomic tools for this species are lacking; even its karyotype is poorly characterized. The guinea pig belongs to Hystricomorpha, a widespread and important group of rodents; so far the chromosomes of guinea pigs have not been compared with that of other hystricomorph species or with any other mammals. We generated full sets of chromosome-specific painting probes for the guinea pig by flow sorting and microdissection, and for the first time, mapped the chromosomal homologies between guinea pig and human by reciprocal chromosome painting. Our data demonstrate that the guinea pig karyotype has undergone extensive rearrangements: 78 synteny-conserved human autosomal segments were delimited in the guinea pig genome. The high rate of genome evolution in the guinea pig may explain why the HSA7/16 and HSA16/19 associations presumed ancestral for eutherians and the three syntenic associations (HSA1/10, 3/19, and 9/11) considered ancestral for rodents were not found in C. porcellus. The comparative chromosome map presented here is a starting point for further development of physical and genetic maps of the guinea pig as well as an aid for genome assembly assignment to specific chromosomes. Furthermore, the comparative mapping will allow a transfer of gene map data from other species. The probes developed here provide a genomic toolkit, which will make the guinea pig a key species to unravel the evolutionary biology of the Hystricomorph rodents.
- Published
- 2015
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- View/download PDF
39. A high-throughput in vivo micronucleus assay for genome instability screening in mice.
- Author
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Balmus G, Karp NA, Ng BL, Jackson SP, Adams DJ, and McIntyre RE
- Subjects
- Animals, Erythrocytes metabolism, Erythropoiesis genetics, Flow Cytometry methods, Mice, Erythropoiesis physiology, Genomic Instability genetics, High-Throughput Screening Assays methods, Micronucleus Tests methods
- Abstract
We describe a sensitive, robust, high-throughput method for quantifying the formation of micronuclei, markers of genome instability, in mouse erythrocytes. Micronuclei are whole chromosomes or chromosome segments that have been separated from the nucleus. Other methods of detection rely on labor-intensive, microscopy-based techniques. Here we describe a 2-d, 96-well plate-based flow cytometric method of micronucleus scoring that is simple enough for a research technician experienced in flow cytometry to perform. The assay detects low levels of genome instability that cannot be readily identified by classic phenotyping, using 25 μl of blood. By using this assay, we have screened >10,000 blood samples and discovered novel genes that contribute to vertebrate genome maintenance, as well as novel disease models and mechanisms of genome instability disorders. We discuss experimental design considerations, including statistical power calculation, we provide troubleshooting tips and we discuss factors that contribute to a false-positive increase in the number of micronucleated red blood cells and to experimental variability.
- Published
- 2015
- Full Text
- View/download PDF
40. A nucleotide signature for identification of Aglaia stellatopilosa Pannell.
- Author
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Ng BL, Omarzuki M, Lau GS, Pannell CM, and Yeo TC
- Subjects
- Classification methods, High-Throughput Nucleotide Sequencing, Nucleotides genetics, Aglaia genetics, DNA, Ribosomal genetics, DNA, Ribosomal Spacer genetics, Phylogeny
- Abstract
Members of the genus Aglaia have been reported to contain bioactive phytochemicals. The genus, belonging to the Meliaceae family, is represented by at least 120 known species of woody trees or shrubs in the tropical rain forest. As some of these species are very similar in their morphology, taxonomic identification can be difficult. A reliable and definitive molecular method which can identify Aglaia to the level of the species will hence be useful in comparing the content of specific bioactive compounds between the species of this genus. Here, we report the analysis of DNA sequences in the internal transcribed spacer (ITS) of the nuclear ribosomal DNA and the observation of a unique nucleotide signature in the ITS that can be used for the identification of Aglaia stellatopilosa. The nucleotide signature consists of nine bases over the length of the ITS sequence (654 bp). This uniqueness was validated in 37 samples identified as Aglaia stellatopilosa by an expert taxonomist, whereas the nucleotide signature was lacking in a selection of other Aglaia species and non-Aglaia genera. This finding suggests that molecular typing could be utilized in the identification of Aglaia stellatopilosa.
- Published
- 2014
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- View/download PDF
41. Chromosomal evolution among leaf-nosed nectarivorous bats--evidence from cross-species chromosome painting (Phyllostomidae, Chiroptera).
- Author
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Sotero-Caio CG, Volleth M, Gollahon LS, Fu B, Cheng W, Ng BL, Yang F, and Baker RJ
- Subjects
- Animals, Biological Evolution, Chiroptera classification, Chromosome Inversion, Humans, Karyotype, Phylogeny, Synteny, Chiroptera genetics, Chromosome Painting methods, Chromosomes
- Abstract
Background: New World leaf-nosed bats, Phyllostomidae, represent a lineage of Chiroptera marked by unprecedented morphological/ecological diversity and extensive intergeneric chromosomal reorganization. There are still disagreements regarding their systematic relationships due to morphological convergence among some groups. Their history of karyotypic evolution also remains to be documented., Results: To better understand the evolutionary relationships within Phyllostomidae, we developed chromosome paints from the bat species Macrotus californicus. We tested the potential of these paints as phylogenetic tools by looking for chromosomal signatures in two lineages of nectarivorous phyllostomids whose independent origins have been statistically supported by molecular phylogenies. By examining the chromosomal homologies defined by chromosome painting among two representatives of the subfamily Glossophaginae (Glossophaga soricina and Anoura cultrata) and one species from the subfamily Lonchophyllinae (Lonchophylla concava), we found chromosomal correspondence in regions not previously detected by other comparative cytogenetic techniques. We proposed the corresponding human chromosomal segments for chromosomes of the investigated species and found two syntenic associations shared by G. soricina and A. cultrata., Conclusion: Comparative painting with whole chromosome-specific paints of M. californicus demonstrates an extensive chromosomal reorganization within the two lineages of nectarivorous phyllostomids, with a large number of chromosomes shared between M. californicus and G. soricina. We show that the evolution of nectar-feeding bats occurs mainly by reshuffling of chiropteran Evolutionarily Conserved Units (ECUs). Robertsonian fusions/fissions and inversions seem to be important modifiers of phyllostomid karyotypes, and autapomorphic character states are common within species. Macrotus californicus chromosome paints will be a valuable tool for documenting the pattern of karyotypic evolution within Phyllostomidae radiation.
- Published
- 2013
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- View/download PDF
42. Massively parallel sequencing reveals the complex structure of an irradiated human chromosome on a mouse background in the Tc1 model of Down syndrome.
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Gribble SM, Wiseman FK, Clayton S, Prigmore E, Langley E, Yang F, Maguire S, Fu B, Rajan D, Sheppard O, Scott C, Hauser H, Stephens PJ, Stebbings LA, Ng BL, Fitzgerald T, Quail MA, Banerjee R, Rothkamm K, Tybulewicz VL, Fisher EM, and Carter NP
- Subjects
- Animals, Chromosomes, Human, Pair 21, Comparative Genomic Hybridization, Disease Models, Animal, Gamma Rays adverse effects, Gene Dosage, Humans, In Situ Hybridization, Fluorescence, Male, Mice, Oligonucleotide Array Sequence Analysis, Recombination, Genetic, Trisomy, Chromosomes, Human radiation effects, Down Syndrome genetics, High-Throughput Nucleotide Sequencing
- Abstract
Down syndrome (DS) is caused by trisomy of chromosome 21 (Hsa21) and presents a complex phenotype that arises from abnormal dosage of genes on this chromosome. However, the individual dosage-sensitive genes underlying each phenotype remain largely unknown. To help dissect genotype--phenotype correlations in this complex syndrome, the first fully transchromosomic mouse model, the Tc1 mouse, which carries a copy of human chromosome 21 was produced in 2005. The Tc1 strain is trisomic for the majority of genes that cause phenotypes associated with DS, and this freely available mouse strain has become used widely to study DS, the effects of gene dosage abnormalities, and the effect on the basic biology of cells when a mouse carries a freely segregating human chromosome. Tc1 mice were created by a process that included irradiation microcell-mediated chromosome transfer of Hsa21 into recipient mouse embryonic stem cells. Here, the combination of next generation sequencing, array-CGH and fluorescence in situ hybridization technologies has enabled us to identify unsuspected rearrangements of Hsa21 in this mouse model; revealing one deletion, six duplications and more than 25 de novo structural rearrangements. Our study is not only essential for informing functional studies of the Tc1 mouse but also (1) presents for the first time a detailed sequence analysis of the effects of gamma radiation on an entire human chromosome, which gives some mechanistic insight into the effects of radiation damage on DNA, and (2) overcomes specific technical difficulties of assaying a human chromosome on a mouse background where highly conserved sequences may confound the analysis. Sequence data generated in this study is deposited in the ENA database, Study Accession number: ERP000439.
- Published
- 2013
- Full Text
- View/download PDF
43. Genetic basis of Y-linked hearing impairment.
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Wang Q, Xue Y, Zhang Y, Long Q, Asan, Yang F, Turner DJ, Fitzgerald T, Ng BL, Zhao Y, Chen Y, Liu Q, Yang W, Han D, Quail MA, Swerdlow H, Burton J, Fahey C, Ning Z, Hurles ME, Carter NP, Yang H, and Tyler-Smith C
- Subjects
- Female, Gene Rearrangement genetics, Humans, Male, Pedigree, Chromosomes, Human, Y genetics, Genes, Y-Linked genetics, Hearing Loss genetics
- Abstract
A single Mendelian trait has been mapped to the human Y chromosome: Y-linked hearing impairment. The molecular basis of this disorder is unknown. Here, we report the detailed characterization of the DFNY1 Y chromosome and its comparison with a closely related Y chromosome from an unaffected branch of the family. The DFNY1 chromosome carries a complex rearrangement, including duplication of several noncontiguous segments of the Y chromosome and insertion of ∼160 kb of DNA from chromosome 1, in the pericentric region of Yp. This segment of chromosome 1 is derived entirely from within a known hearing impairment locus, DFNA49. We suggest that a third copy of one or more genes from the shared segment of chromosome 1 might be responsible for the hearing-loss phenotype., (Copyright © 2013 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)
- Published
- 2013
- Full Text
- View/download PDF
44. Tracking chromosome evolution in southern African gerbils using flow-sorted chromosome paints.
- Author
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Knight LI, Ng BL, Cheng W, Fu B, Yang F, and Rambau RV
- Subjects
- Animals, Chromosome Banding, Chromosome Inversion, DNA Probes genetics, Genetic Speciation, Gerbillinae classification, In Situ Hybridization, Fluorescence, Karyotype, Male, Phylogeny, Sensitivity and Specificity, Species Specificity, Time Factors, Chromosome Painting methods, Chromosomes, Mammalian genetics, Evolution, Molecular, Gerbillinae genetics
- Abstract
Desmodillus and Gerbilliscus (formerly Tatera) comprise a monophyletic group of gerbils (subfamily Gerbillinae) which last shared an ancestor approximately 8 million years ago; diploid chromosome number variation among the species ranges from 2n = 36 to 2n = 50. In an attempt to shed more light on chromosome evolution and speciation in these rodents, we compared the karyotypes of 7 species, representing 3 genera, based on homology data revealed by chromosome painting with probes derived from flow-sorted chromosomes of the hairy footed gerbil, Gerbillurus paeba (2n = 36). The fluorescent in situ hybridization data revealed remarkable genome conservation: these species share a high proportion of conserved chromosomes, and differences are due to 10 Robertsonian (Rb) rearrangements (3 autapomorphies, 3 synapomorphies and 4 hemiplasies/homoplasies). Our data suggest that chromosome evolution in Desmodillus occurred at a rate of ~1.25 rearrangements per million years (Myr), and that the rate among Gerbilliscus over a time period spanning 8 Myr is also ~1.25 rearrangements/Myr. The recently diverged Gerbillurus (G. tytonis and G. paeba) share an identical karyotype, while Gerbilliscus kempi, G. afra and G. leucogaster differ by 6 Rb rearrangements (a rate of ~1 rearrangement/Myr). Thus, our data suggests a very slow rate of chromosomal evolution in Southern African gerbils., (Copyright © 2013 S. Karger AG, Basel.)
- Published
- 2013
- Full Text
- View/download PDF
45. Genome sequencing and analysis of the Tasmanian devil and its transmissible cancer.
- Author
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Murchison EP, Schulz-Trieglaff OB, Ning Z, Alexandrov LB, Bauer MJ, Fu B, Hims M, Ding Z, Ivakhno S, Stewart C, Ng BL, Wong W, Aken B, White S, Alsop A, Becq J, Bignell GR, Cheetham RK, Cheng W, Connor TR, Cox AJ, Feng ZP, Gu Y, Grocock RJ, Harris SR, Khrebtukova I, Kingsbury Z, Kowarsky M, Kreiss A, Luo S, Marshall J, McBride DJ, Murray L, Pearse AM, Raine K, Rasolonjatovo I, Shaw R, Tedder P, Tregidgo C, Vilella AJ, Wedge DC, Woods GM, Gormley N, Humphray S, Schroth G, Smith G, Hall K, Searle SM, Carter NP, Papenfuss AT, Futreal PA, Campbell PJ, Yang F, Bentley DR, Evers DJ, and Stratton MR
- Subjects
- Animals, Clonal Evolution, Endangered Species, Facial Neoplasms epidemiology, Facial Neoplasms genetics, Facial Neoplasms pathology, Female, Genome-Wide Association Study, Male, Molecular Sequence Data, Tasmania epidemiology, Facial Neoplasms veterinary, Genomic Instability, Marsupialia genetics, Mutation
- Abstract
The Tasmanian devil (Sarcophilus harrisii), the largest marsupial carnivore, is endangered due to a transmissible facial cancer spread by direct transfer of living cancer cells through biting. Here we describe the sequencing, assembly, and annotation of the Tasmanian devil genome and whole-genome sequences for two geographically distant subclones of the cancer. Genomic analysis suggests that the cancer first arose from a female Tasmanian devil and that the clone has subsequently genetically diverged during its spread across Tasmania. The devil cancer genome contains more than 17,000 somatic base substitution mutations and bears the imprint of a distinct mutational process. Genotyping of somatic mutations in 104 geographically and temporally distributed Tasmanian devil tumors reveals the pattern of evolution and spread of this parasitic clonal lineage, with evidence of a selective sweep in one geographical area and persistence of parallel lineages in other populations., (Copyright © 2012 Elsevier Inc. All rights reserved.)
- Published
- 2012
- Full Text
- View/download PDF
46. Management of chronic kidney disease in the elderly.
- Author
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Ng BL and Anpalahan M
- Subjects
- Age Factors, Aged, Disease Management, Humans, Kidney Failure, Chronic diagnosis, Kidney Failure, Chronic epidemiology, Kidney Failure, Chronic therapy, Renal Dialysis methods, Renal Insufficiency, Chronic epidemiology, Renal Insufficiency, Chronic diagnosis, Renal Insufficiency, Chronic therapy
- Abstract
Both chronic kidney disease (CKD) and end-stage renal disease are strongly age related. Although the morbidity and mortality of CKD have significantly improved in recent years because of a greater understanding of its pathophysiology and evidence-based approach to management, the application of this evidence to the elderly CKD patients is often fraught with difficulty. This is because, besides age, the clinical and biological variables that are widely prevalent in the elderly, such as multiple co-morbidities, functional impairments and polypharmacy, and quality of life and functional outcome measures, which are pertinent to this age group, have generally not been incorporated into the available evidence. This paper reviews the current evidence with a view to providing a framework for diagnosing and managing CKD in the elderly. Special references are made to age-related physiological changes in the renal system, assessment of renal function, and management of metabolic complications and end-stage renal disease., (© 2011 The Authors. Internal Medicine Journal © 2011 Royal Australasian College of Physicians.)
- Published
- 2011
- Full Text
- View/download PDF
47. Molecular cytogenetic characterization of the genome organization of the 6-banded armadillo (Euphractus sexcinctus).
- Author
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Liu Y, Ye J, Fu B, Ng BL, Wang J, Su W, Yang F, and Nie W
- Subjects
- Animals, Base Sequence, Chromosome Banding, Female, In Situ Hybridization, Fluorescence, Karyotyping, Molecular Sequence Data, Sequence Homology, Nucleic Acid, Armadillos genetics, Genome
- Abstract
Xenarthra, as the probable earliest offshoot of the placental tree, represents a key taxon for understanding mammalian phylogeny. To gain further insight into the chromosomal evolution and genome organization of the xenarthrans, we have established the first genome-wide comparative chromosome map between human and the 6-banded armadillo (Euphractussexcinctus, 2n = 58), a basal species on the Xenarthra branch, by reciprocal cross-species chromosome painting. In total, 22 human autosomal paints revealed 41 homologous segments in the euchromatic genome of E. sexcinctus. Our results provide further support for the notion that the 2 human homologous segmental associations, i.e. HSA 2/8 and 7a/10p, could constitute the synapomorphies that unite the xenarthrans. Moreover, we propose that the putative ancestral Xenarthra karyotype closely resemble the 2n = 54 karyotype of the E. sexcinctus, consisting of the equivalents of HSA1p, 1q, 2a, 2b, 2c/8c, 3/21, 4a, 4b/8b, 5, 6a, 6b, 7a/10p, 7b/16p, 8a, 9, 10q, 11, 12a/22a, 12b/22b, 13, 14/15, 16q/19q, 17, 18, 19p, 20, and X. In addition, we have analysed the C-banding patterns of E. sexcinctus, and cloned, FISHmapped and sequenced 7 novel repetitive DNA segments, providing further information on the complexity of genome architecture of E. sexcinctus., (Copyright © 2010 S. Karger AG, Basel.)
- Published
- 2011
- Full Text
- View/download PDF
48. Anti-N-methyl-D-aspartate receptor encephalitis in a young woman with an ovarian tumour.
- Author
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Lo JW, Leung EY, Ng BL, Fu MH, Yip KK, Chan RT, and Chang CM
- Subjects
- Diagnosis, Differential, Dyskinesias etiology, Encephalitis diagnosis, Encephalitis etiology, Female, Hong Kong, Humans, Teratoma complications, Young Adult, Encephalitis immunology, Ovarian Neoplasms complications, Receptors, N-Methyl-D-Aspartate immunology
- Abstract
Anti-N-methyl-D-aspartate receptor encephalitis is characterised by psychiatric and neurological abnormalities and occurs in frequent association with ovarian teratoma. We report the first confirmed case of teratoma-associated anti-N-methyl-D-aspartate receptor encephalitis in Hong Kong in a young woman presenting with confusion and prominent dyskinesia, followed by a review of the current literature.
- Published
- 2010
49. Reprogramming of T cells to natural killer-like cells upon Bcl11b deletion.
- Author
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Li P, Burke S, Wang J, Chen X, Ortiz M, Lee SC, Lu D, Campos L, Goulding D, Ng BL, Dougan G, Huntly B, Gottgens B, Jenkins NA, Copeland NG, Colucci F, and Liu P
- Subjects
- Animals, Cell Line, Tumor, Cells, Cultured, Coculture Techniques, Cytotoxicity, Immunologic, Gene Deletion, Gene Expression Profiling, Gene Expression Regulation, Developmental, Gene Knock-In Techniques, Genes, T-Cell Receptor beta, Killer Cells, Natural cytology, Killer Cells, Natural immunology, Melanoma, Experimental immunology, Melanoma, Experimental therapy, Mice, Mice, Inbred C57BL, Mice, Knockout, Oligonucleotide Array Sequence Analysis, Precursor Cells, T-Lymphoid cytology, Precursor Cells, T-Lymphoid physiology, Receptors, Antigen, T-Cell, alpha-beta metabolism, Signal Transduction, Stromal Cells cytology, Stromal Cells physiology, T-Lymphocytes cytology, T-Lymphocytes immunology, T-Lymphocytes transplantation, Tamoxifen analogs & derivatives, Tamoxifen pharmacology, Cell Lineage, Killer Cells, Natural physiology, Lymphopoiesis genetics, Repressor Proteins genetics, Repressor Proteins metabolism, T-Lymphocytes physiology, Tumor Suppressor Proteins genetics, Tumor Suppressor Proteins metabolism
- Abstract
T cells develop in the thymus and are critical for adaptive immunity. Natural killer (NK) lymphocytes constitute an essential component of the innate immune system in tumor surveillance, reproduction, and defense against microbes and viruses. Here, we show that the transcription factor Bcl11b was expressed in all T cell compartments and was indispensable for T lineage development. When Bcl11b was deleted, T cells from all developmental stages acquired NK cell properties and concomitantly lost or decreased T cell-associated gene expression. These induced T-to-natural killer (ITNK) cells, which were morphologically and genetically similar to conventional NK cells, killed tumor cells in vitro, and effectively prevented tumor metastasis in vivo. Therefore, ITNKs may represent a new cell source for cell-based therapies.
- Published
- 2010
- Full Text
- View/download PDF
50. Laser excitation power and the flow cytometric resolution of complex karyotypes.
- Author
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Ng BL and Carter NP
- Subjects
- Cell Line, Tumor, Cells, Cultured, Humans, Flow Cytometry methods, Karyotyping, Lasers
- Abstract
The analytical resolution of individual chromosome peaks in the flow karyotype of cell lines is dependent on sample preparation and the detection sensitivity of the flow cytometer. We have investigated the effect of laser power on the resolution of chromosome peaks in cell lines with complex karyotypes. Chromosomes were prepared from a human gastric cancer cell line and a cell line from a patient with an abnormal phenotype using a modified polyamine isolation buffer. The stained chromosome suspensions were analyzed on a MoFlo sorter (Beckman Coulter) equipped with two water-cooled lasers (Coherent). A bivariate flow karyotype was obtained from each of the cell lines at various laser power settings and compared to a karyotype generated using laser power settings of 300 mW. The best separation of chromosome peaks was obtained with laser powers of 300 mW. This study demonstrates the requirement for high-laser powers for the accurate detection and purification of chromosomes, particularly from complex karyotypes, using a conventional flow cytometer., (Copyright 2010 International Society for Advancement of Cytometry.)
- Published
- 2010
- Full Text
- View/download PDF
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