Displaying publications 41 - 60 of 76 in total

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  1. Martins RF, Fickel J, Le M, van Nguyen T, Nguyen HM, Timmins R, et al.
    BMC Evol. Biol., 2017 01 26;17(1):34.
    PMID: 28122497 DOI: 10.1186/s12862-017-0888-0
    BACKGROUND: The members of the genus Muntiacus are of particular interest to evolutionary biologists due to their extreme chromosomal rearrangements and the ongoing discussions about the number of living species. Red muntjacs have the largest distribution of all muntjacs and were formerly considered as one species. Karyotype differences led to the provisional split between the Southern Red Muntjac (Muntiacus muntjak) and the Northern Red Muntjac (M. vaginalis), but uncertainties remain as, so far, no phylogenetic study has been conducted. Here, we analysed whole mitochondrial genomes of 59 archival and 16 contemporaneous samples to resolve uncertainties about their taxonomy and used red muntjacs as model for understanding the evolutionary history of other species in Southeast Asia.

    RESULTS: We found three distinct matrilineal groups of red muntjacs: Sri Lankan red muntjacs (including the Western Ghats) diverged first from other muntjacs about 1.5 Mya; later northern red muntjacs (including North India and Indochina) and southern red muntjacs (Sundaland) split around 1.12 Mya. The diversification of red muntjacs into these three main lineages was likely promoted by two Pleistocene barriers: one through the Indian subcontinent and one separating the Indochinese and Sundaic red muntjacs. Interestingly, we found a high level of gene flow within the populations of northern and southern red muntjacs, indicating gene flow between populations in Indochina and dispersal of red muntjacs over the exposed Sunda Shelf during the Last Glacial Maximum.

    CONCLUSIONS: Our results provide new insights into the evolution of species in South and Southeast Asia as we found clear genetic differentiation in a widespread and generalist species, corresponding to two known biogeographical barriers: The Isthmus of Kra and the central Indian dry zone. In addition, our molecular data support either the delineation of three monotypic species or three subspecies, but more importantly these data highlight the conservation importance of the Sri Lankan/South Indian red muntjac.

    Matched MeSH terms: Karyotyping
  2. Lum SH, Chin TF, Lau KH, Yap TY, Rajagopal R, Ariffin H
    Int J Hematol, 2014 Mar;99(3):215-6.
    PMID: 24470150 DOI: 10.1007/s12185-014-1515-0
    Matched MeSH terms: Karyotyping/methods
  3. Ni Chin WH, Li Z, Jiang N, Lim EH, Suang Lim JY, Lu Y, et al.
    J Mol Diagn, 2021 10;23(10):1359-1372.
    PMID: 34365011 DOI: 10.1016/j.jmoldx.2021.07.013
    Despite the immense genetic heterogeneity of B-lymphoblastic leukemia [or precursor B-cell acute lymphoblastic leukemia (B-ALL)], RNA sequencing (RNA-Seq) could comprehensively interrogate its genetic drivers, assigning a specific molecular subtype in >90% of patients. However, study groups have only started to use RNA-Seq. For broader clinical use, technical, quality control, and appropriate performance validation are needed. We describe the development and validation of an RNA-Seq workflow for subtype classification, TPMT/NUDT15/TP53 variant discovery, and immunoglobulin heavy chain (IGH) disease clone identification for Malaysia-Singapore acute lymphoblastic leukemia (ALL) 2020. We validated this workflow in 377 patients in our preceding Malaysia-Singapore ALL 2003/Malaysia-Singapore ALL 2010 studies and proposed the quality control measures for RNA quality, library size, sequencing, and data analysis using the International Organization for Standardization 15189 quality and competence standard for medical laboratories. Compared with conventional methods, we achieved >95% accuracy in oncogene fusion identification, digital karyotyping, and TPMT and NUDT15 variant discovery. We found seven pathogenic TP53 mutations, confirmed with Sanger sequencing, which conferred a poorer outcome. Applying this workflow prospectively to the first 21 patients in Malaysia-Singapore ALL 2020, we identified the genetic drivers and IGH disease clones in >90% of patients with concordant TPMT, NUDT15, and TP53 variants using PCR-based methods. The median turnaround time was 12 days, which was clinically actionable. In conclusion, RNA-Seq workflow could be used clinically in management of B-cell ALL patients.
    Matched MeSH terms: Karyotyping/methods
  4. Ahzad HA, Ramli SF, Loong TM, Salahshourifar I, Zilfalil BA, Yusoff NM
    Kobe J Med Sci, 2010;56(2):E79-84.
    PMID: 21063149
    Ring chromosome 6, especially if it is de novo, is a rare occurrence. The phenotype of patients with ring chromosome 6 can be highly variable ranging from almost normal to severe malformations and mental retardation. The size and structure of the ring chromosome as well as the level of mosaicism are important factors in determining the clinical phenotype. Here we report an eight month-old child, a product of a non consanguineous marriage, who presented with developmental retardation, hypertelorism, microcephaly, flat occiput, broad nasal bridge, large ears, micrognathia, wide spaced nipples, protruding umbilicus, short stubby fingers, clinodactyly, single palmar crease, short neck with no obvious webbing, and congenital heart defect. Conventional karyotyping and Whole Chromosome Paint of the peripheral leukocytes showed 46,XY,r(6)(p25q27) karyotype with plausible breakpoints at p25 and q27 end. Conventional karyotyping of both parents showed normal karyotype. To the best of our knowledge, this is the first report of a Malay individual with ring chromosome 6, and this report adds to the collective knowledge of this rare chromosome abnormality.
    Matched MeSH terms: Karyotyping
  5. Kannan TP, Nik Ahmad Shah NL, Azlina A, Samsudin AR, Narazah MY, Salleh M
    Med J Malaysia, 2004 May;59 Suppl B:168-9.
    PMID: 15468871
    The present study is aimed at finding the mutagenicity and cytotoxicity of dense form of synthetic hydroxyapatite (Source: School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia) in the blood of sheep. The biomaterial was implanted in the tibia of Malin, an indigenous sheep breed of Malaysia. Blood was collected from the sheep before implantation of the biomaterial, cultured and a karyological study was made. Six weeks after implantation, blood was collected from the same animal, cultured and screened for chromosome aberrations. The mitotic indices and karyological analysis indicated that the implantation of synthetic hydroxyapatite (dense form) did not produce any cytotoxicity or chromosome aberrations in the blood of sheep.
    Matched MeSH terms: Karyotyping
  6. Meng Z, Han J, Lin Y, Zhao Y, Lin Q, Ma X, et al.
    Theor Appl Genet, 2020 Jan;133(1):187-199.
    PMID: 31587087 DOI: 10.1007/s00122-019-03450-w
    KEY MESSAGE: A novel tetraploid S. spontaneum with basic chromosome x = 10 was discovered, providing us insights in the origin and evolution in Saccharum species. Sugarcane (Saccharum spp., Poaceae) is a leading crop for sugar production providing 80% of the world's sugar. However, the genetic and genomic complexities of this crop such as its high polyploidy level and highly variable chromosome numbers have significantly hindered the studies in deciphering the genomic structure and evolution of sugarcane. Here, we developed the first set of oligonucleotide (oligo)-based probes based on the S. spontaneum genome (x = 8), which can be used to simultaneously distinguish each of the 64 chromosomes of octaploid S. spontaneum SES208 (2n = 8x = 64) through fluorescence in situ hybridization (FISH). By comparative FISH assay, we confirmed the chromosomal rearrangements of S. spontaneum (x = 8) and S. officinarum (2n = 8x = 80), the main contributors of modern sugarcane cultivars. In addition, we examined a S. spontaneum accession, Np-X, with 2n = 40 chromosomes, and we found that it was a tetraploid with the unusual basic chromosome number of x = 10. Assays at the cytological and DNA levels demonstrated its close relationship with S. spontaneum with basic chromosome number x = 8 (the most common accessions in S. spontaneum), confirming its S. spontaneum identity. Population genetic structure and phylogenetic relationship analyses between Np-X and 64 S. spontaneum accessions revealed that Np-X belongs to the ancient Pan-Malaysia group, indicating a close relationship to S. spontaneum with basic chromosome number of x = 8. This finding of a tetraploid S. spontaneum with basic chromosome number of x = 10 suggested a parallel evolution path of genomes and polyploid series in S. spontaneum with different basic chromosome numbers.
    Matched MeSH terms: Karyotyping
  7. Julia Mohd Idris, Zariyantey Abd Hamid, Ng, Khen Eng, Chow, Paik Wah, Salwati Shuib, Mathialagan, Ramya Dewi
    MyJurnal
    Benzene exposure has been associated with hematotoxicity and leukemogenicity. However, the impact of benzene exposure on complex microenvironment of Hematopoetic Stem Cells (HSCs) niche, comprising of HSCs and lineage-specific progenitors remains elusive. Thus, a study on benzene-targeting HSCs niche could uncover mechanism linking benzene to HSCs niche alteration. This study evaluates the lineage-specific responses following exposure to a benzene metabolite, namely hydroquinone (HQ) in targeting HSCs and myeloid-committed progenitors. Freshly isolated murine bone marrow cells (BMCs) were exposed to HQ at series of concentrations (0 – 50 μM) for 24 hours; followed by cell viability analysis using MTT assay. Chromosomal aberration (CA) status was determined using karyotyping analysis. Expression of surface antigen for HSCs (Sca-1) was confirmed by flow cytometer. Lineage-specific myelotoxicity was studied using the colony-forming unit (CFU) assay for the following myeloid progenitors: CFU granulocyte /erythrocyte /macrophage /megakaryocyte (CFU-GEMM), CFU-granulocyte/macrophage (CFU-GM), CFU-granulocyte (CFU-G), CFU-macrophage (CFU-M), CFU-erythroid (CFU-E) and Burst-forming unit erythroid (BFU-E). HQ reduced (p
    Matched MeSH terms: Karyotyping
  8. King M, King D
    Aust. J. Biol. Sci., 1975 Feb;28(1):89-108.
    PMID: 1164258
    The karyotypes have been determined of 16 of the 32 species of the genus Varanus, including animals from Africa, Israel, Malaya and Australia. A constant chromosome number of 2n = 40 was observed. The karyotype is divided into eight pairs of large chromosomes and 12 paris of microchromosomes. A series of chromosomal rearrangements have become established in both size groups of the karyotype and are restricted to centromers shifts, probably caused by pericentric inversion. Species could be placed in one of six distinct karyotype groups which are differentiated by these rearrangements and whose grouping does not always correspond with the current taxonomy. An unusual sex chromosome system of the ZZ/ZW type was present in a number of the species examined. The evolutionary significance of these chromosomal rearrangements, their origin and their mode of establishment are discussed and related to the current taxonomic groupings. The most likely phylogenetic model based on chromosome morphology, fossil evidence and the current distribution of the genus Varanus is presented.
    Matched MeSH terms: Karyotyping
  9. Siti Mariam I, Suhaida MA, Tarmizi AB, Norhasimah M, Nor Atifah MA, Kannan, T. P., et al.
    MyJurnal
    Down Syndrome (DS), is a complex genetic disease resulting from the presence of 3 copies of chromosome 21. It is the most common autosomal abnormality among live births and the most commonly recognized genetic cause of mental retardation. The only well established risk factor for DS is advanced maternal age. The Human Genome Center , University Sains Malaysia, Kelantan has been carrying out cytogenetic studies in DS patients. Here we, report the karyotype pattern of Down Syndrome patients in correlation with maternal age, among referral cases to our Center.
    Matched MeSH terms: Karyotyping
  10. Norhasimah, M.M., Ahmad Tarmizi, A.B., Azman, B.A., Zilfalil, B.A., Ankathil, R.
    MyJurnal
    Generally, the karyotype profile of Down Syndrome has been reported to be full trisomy 21 in 92% of patients, mosaic trisomy 21 in 4% of patients and translocation involving chromosome 21 in 4% of patients in most of the population groups worldwide. But, karyotype analysis of 149 DS patients at the Human Genome Center, USM, during the past five years revealed that free trisomy accounted for 94.6%, mosaic trisomy 21 for 4.7% and translocation involving chromosome 21 in 0.7% of the Down Syndrome etiology in North East Malaysian population, indicating a low frequency of translocation DS in this region. Here, we report one case of translocation Down Syndrome encountered during karyotype analysis of 149 DS cases. Karyotype showed a robertsonian translocation where an entire extra chromosome 21 was attached to the centromere of one of the chromosome 14, resulting in a derivative chromosome 14 with attached chromosome 21. Karyotype analysis of the parents revealed a normal 46,XY pattern for father and 46,XX pattern for mother indicating that this robertsonian translocation had arisen de novo either prior to or at conception.
    Matched MeSH terms: Karyotyping
  11. Ambayya, Angeli, Sasmita, Andrew Octavian, Zainina Seman, Chang, Kian Meng, Sathar, Jameela, Yegappan, Subramanian, et al.
    MyJurnal
    Insights into molecular karyotyping using comparative genomic hybridization (CGH) and single nucleotide polymorphism (SNP) arrays enable the identification of copy number variations (CNVs) at a higher resolution and facilitate the detection of copy neutral loss of heterozygosity (CN-LOH) otherwise undetectable by conventional cytogenetics. The applicability of a customised CGH+SNP 180K DNA microarray in the diagnostic evaluation of Acute Myeloid Leukaemia (AML) in comparison with conventional karyotyping was assessed in this study. Methods: Paired tumour and germline post induction (remission sample obtained from the same patient after induction) DNA were used to delineate germline variants in 41 AML samples and compared with the karyotype findings. Results: After comparing the tumour versus germline DNA, a total of 55 imbalances (n 5-10 MB = 21, n 10-20 MB = 8 and n >20 MB = 26) were identified. Gains were most common in chromosome 4 (26.7%) whereas losses were most frequent in chromosome 7 (28.6%) and X (25.0%). CN-LOH was mostly seen in chromosome 4 (75.0%). Comparison between array CGH+SNP and karyotyping revealed 20 cases were in excellent agreement and 13 cases did not concord whereas in 15 cases finding could not be confirmed as no karyotypes available. Conclusion: The use of a combined array CGH+SNP in this study enabled the detection of somatic and germline CNVs and CN-LOHs in AML. Array CGH+SNP accurately determined chromosomal breakpoints compared to conventional cytogenetics in relation to presence of CNVs and CN-LOHs.
    Matched MeSH terms: Karyotyping
  12. Pal S, Ma SO, Norhasimah M, Suhaida MA, Siti Mariam I, Ankathil R, et al.
    Singapore Med J, 2009 Oct;50(10):1008-12.
    PMID: 19907893
    This study was done to determine the prevalence of chromosomal abnormalities and the subsequent reproductive outcome in couples who had two or more miscarriages.
    Matched MeSH terms: Karyotyping
  13. Yip CH, Pathmanathan R
    Singapore Med J, 1996 Feb;37(1):117-8.
    PMID: 8783930
    A case report of a male true hermaphrodite with 46XX/46XY karyotype is presented. He was first diagnosed at the age of 9 years when he presented with hypospadias and a left undescended testis. He was lost to follow-up until he presented at the age of 23 years with bilateral gynaecomastia. A hormonal profile showed a low testosterone level, while a seminal assay showed very few sperms. However he claimed to be sexually active. A year later, after he got married, he began to complain of impotence. A review of the condition is presented.
    Matched MeSH terms: Karyotyping
  14. Azman BZ, Akhir SM, Zilfalil BA, Ankathil R
    Singapore Med J, 2008 Apr;49(4):e98-e100.
    PMID: 18418516
    We report two cases of deletion 5p or cri du chat syndrome (CdCS) with different presentations and risks of transmission: one case with paternal chromosome 5 involvement and another, a de novo case with atypical clinical presentation. Cytogenetic analysis was performed on the two cases and their parents. GTG-banded karyotype analysis of Cases 1 and 2 revealed abnormal 46,XY,del(5)(p13-15) male karyotypes. For Case 1, the mother showed normal female karyotype while the father showed an abnormal karyotype involving a balanced translocation 46,XY,t(5;10)(p13;p15). For Case 2, however, both parents showed a normal karyotype pattern. In Case 1, the clinical features, particularly the distinct facial phenotype in combination with a characteristic cat-like cry and hypotonia, aided in the diagnosis at birth and the karyotype analysis was resolutive. The boy in Case 2 presented with atypical clinical features. Even though this patient had multiple syndromic features, the typical high pitched cat-like cry was not prominent. Instead, the patient manifested persistent stridor (from day three of life), which might have prevented the clinician from suspecting CdCS at birth. However, when this patient was presented at seven months of age for cytogenetic analysis, a confirmatory diagnosis of CdCS was established. For children with congenital abnormalities, an early clinical diagnosis confirmed through cytogenetic and molecular investigations, is important for providing personalised diagnostic and prognostic evaluation, and also for genetic counselling on the reproductive risk, particularly for patients with parental chromosome translocation involvement.
    Matched MeSH terms: Karyotyping
  15. Mdzin R, Ko C, Abdul Latif Z, Zakaria Z
    Singapore Med J, 2008 Nov;49(11):e336-9.
    PMID: 19037546
    Interstitial deletions of the long arm of chromosome 4 are rare. The deletions may occur at the proximal or the distal portions of the chromosome and different breakpoints may be involved. We report an interstitial deletion of 4q: 46XY der 4 (q28;q35) in a six-year-old boy with dysmorphic features associated with moderate mental retardation. Parental chromosomal analysis showed a balanced paternal translocation.
    Matched MeSH terms: Karyotyping
  16. Ten SK, Khor MK, Khalid H, Lin HP, Ng SC, Cheong SK, et al.
    Singapore Med J, 1992 Apr;33(2):164-6.
    PMID: 1621121
    The haematological findings and case history of 3 patients with the association of acute myeloid leukemia and translocation involving the long arm of chromosome no. 11 are presented. The recipient chromosome for the translocated material from chromosome 11 differs in all the three cases being namely chromosomes 1, 10 and 17.
    Matched MeSH terms: Karyotyping
  17. Noor PJ, Chin YM, Ten SK, Hassan K
    Singapore Med J, 1987 Jun;28(3):235-40.
    PMID: 2958941
    A cytogenetic survey 01 124 children in lour special schools for the mentally handicapped was carried out to determine the contribution of chromosomal abnormalities to the aetiology of mental retardation in these children. All the children were karyotyped employing the G·banding technique 01 43 (34.7%) with an abnormal chromosome complement, 40 had Down's Syndrome, and 3 had other chromosomal abnormalities, namely a translocation 1;17, a mosaic male/trisomy 18 and a Klinefelter's syndrome. Polymorphic variants involving chromosomes 1, 9, and 14 were also observed. Two other children showed variants of the Y chromosome (one a small Y and the other a metacentric Y). The possible contribution by these abnormal variants to mental retardation is discussed. Details of the abnormal cytogenetic findings are reported.
    Matched MeSH terms: Karyotyping
  18. Yosida TH, Sagai T
    Chromosoma, 1975;50(3):283-300.
    PMID: 1149576
    All subspecies of black rats (Rattus rattus) used in the present study are characterized by having large and clear C-bands at the centromeric region. The appearance of the bands, however, is different in the subspecies. Chromosome pair No. 1 in Asian type black rats (2n=42), which are characterized by an acrocentric and subtelocentric polymorphism, showed C-band polymorphism. In Phillipine rats (R. rattus mindanensis) the pair was subtelocentric with C-bands, but in Malayan black rats (R. rattus diardii) it was usually acrocentric with C-bands. In Hong-Kong (R. rattus flavipectus) and Japanese black rats (R. rattus tanezumi) it was polymorphic with respect to the presence of acrocentrics with C-bands or subtelocentrics without C-bands. The other chromosomes pairs showed clear C-bands, but in Hong-Kong black rats the pairs No. 2 and 5 were polymorphic with and without C-bands. In Japanese black rats, 6 chromosome pairs (No. 3, 4, 7, 9, 11 and 13) were polymorphic in regard to presence and absence of C-bands, but the other 5 chromosome pairs (No. 2, 5, 6, 8 and 10) showed always absence of C-bands. Only pair No. 12 usually showed C-bands. C-bands in small metacentric pairs (No. 14 to 20) in Asian type black rats generally large in size, but those in the Oceanian (2n=38) and Ceylon type black rats (2n=40) were small. In the hybrids between Asian and Oceanian type rats, heteromorphic C-bands, one large and the other small, were observed. Based on the consideration of karyotype evolution in the black rats, the C-band is suggested to have a tendency toward the diminution as far as the related species are concerned.
    Matched MeSH terms: Karyotyping
  19. Lee YL, Wu LL
    J ASEAN Fed Endocr Soc, 2019;34(1):22-28.
    PMID: 33442133 DOI: 10.15605/jafes.034.01.05
    Objectives: Diagnosis of Turner syndrome in Malaysia is often late. This may be due to a lack of awareness of the wide clinical variability in this condition. In our study, we aim to examine the clinical features of all our Turner patients during the study period and at presentation.

    Methodology: This was a cross-sectional study. Thirty-four (34) Turner patients were examined for Turner-specific clinical features. The karyotype, clinical features at presentation, age at diagnosis and physiologic features were retrieved from their medical records.

    Results: Patients with 45,X presented at a median age of 1 month old with predominantly lymphoedema and webbed neck. Patients with chromosome mosaicism or structural X abnormalities presented at a median age of 11 years old with a broader clinical spectrum, short stature being the most common presenting clinical feature. Cubitus valgus deformity, nail dysplasia and short 4th/5th metacarpals or metatarsals were common clinical features occurring in 85.3%-94.1% of all Turner patients. Almost all patients aged ≥2 years were short irrespective of karyotype.

    Conclusion: Although short stature is a universal finding in Turner patients, it is usually unrecognised till late. Unlike the 45,X karyotype, non-classic Turner syndrome has clinical features which may be subtle and difficult to discern. Our findings underscore the importance of proper serial anthropometric measurements in children. Awareness for the wide spectrum of presenting features and careful examination for Turner specific clinical features is crucial in all short girls to prevent a delay in diagnosis.

    Matched MeSH terms: Karyotyping
  20. Lau EYC, Fung YK
    J ASEAN Fed Endocr Soc, 2020;35(1):114-117.
    PMID: 33442178 DOI: 10.15605/jafes.035.01.19
    45,X/46,XY mosaicism is a rare disorder with a wide heterogeneity in its manifestations. An 18-year-old girl was referred to the endocrine clinic for investigation of her primary amenorrhea. Clinical examination was unremarkable. Hormonal profile was consistent with primary ovarian insufficiency and human chorionic gonadotropin (hCG) stimulation did not show evidence of active testicular tissue. Karyotyping studies by G-banding revealed a 45,X/46,XY karyotype. She was diagnosed with mosaic Turner syndrome with Y chromosomal material and investigation was performed to identify the presence of male gonads due to the risk of gonadal malignancy. Magnetic resonance imaging (MRI) of the pelvis did not show evidence of gonads. Laparoscopic exploration was proposed but the patient and parents refused opting for conservative management. This case highlights the challenges in the management of this rare condition.
    Matched MeSH terms: Karyotyping
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