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Ma S, Shen S, Lee H, Eriksson M, Zeng X, Xu J, Fandrick K, Yee N, Senanayake C, Grinberg N. Mechanistic studies on the chiral recognition of polysaccharide-based chiral stationary phases using liquid chromatography and vibrational circular dichroism. J Chromatogr A 2009; 1216:3784-93. [DOI: 10.1016/j.chroma.2009.02.046] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2008] [Revised: 02/09/2009] [Accepted: 02/16/2009] [Indexed: 10/21/2022]
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277
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Phua HP, Chua AV, Ma S, Heng D, Chew SK. Singapore's burden of disease and injury 2004. Singapore Med J 2009; 50:468-478. [PMID: 19495514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
INTRODUCTION The Singapore Burden of Disease (SBoD) Study 2004 provides a comprehensive and detailed assessment of the size and distribution of health problems in Singapore. It is the first local study to use disability-adjusted life years (DALYs) to quantify the total disease burden. METHODS The SBoD study applied the methods developed for the original Global Burden of Disease study to data specific to Singapore to compute the DALYs. DALY is a summary measure of population health that combines time lost due to premature mortality (years of life lost [YLL]) with time spent in ill-health (broadly-termed disability) arising from incident cases of disease or injury (years of life lost due to disability [YLD]). DALYs, stratified by gender and age group, were calculated for more than 130 specific health conditions for the Singapore resident population for the year 2004. RESULTS In 2004, diabetes mellitus, ischaemic heart disease and stroke were the top three leading causes of premature death and ill-health in Singapore, and together accounted for more than one-quarter (28 percent) of the total disease burden (in DALYs). Morbidity burden (YLD) was responsible for 52 percent of the total DALYs, with diabetes mellitus, anxiety and depression, and Alzheimer's disease and other dementias being the main sources of the total YLDs. Ischaemic heart disease, stroke and lung cancer were the major contributors to the premature mortality burden (YLL). CONCLUSION This study provides an objective and systematic assessment of the fatal and nonfatal health conditions in Singapore to support priority setting in public health policies and research.
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Ferguson KA, Leung S, Jiang D, Ma S. Distribution of MLH1 foci and inter-focal distances in spermatocytes of infertile men. Hum Reprod 2009; 24:1313-21. [DOI: 10.1093/humrep/dep021] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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279
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Chen Z, Ma S, Dutta NK. Multiwavelength fiber ring laser based on a semiconductor and fiber gain medium. OPTICS EXPRESS 2009; 17:1234-1239. [PMID: 19188950 DOI: 10.1364/oe.17.001234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We report a novel multi-wavelength laser source based on hybrid gain medium, with a semiconductor optical amplifier and erbium doped fiber amplifier, and a double-ring structure. More than 60 lines with more than 50 dB signal-to-noise ratio (SNR) have been achieved in our setup. The wavelength interval between the wavelengths is approximately 0.32 nm. The 3 dB spectral width of each lasing line is approximately 0.019 nm. The laser can be tuned from approximately 1526 nm to approximately 1562 nm by adjusting the loss in the cavity.
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280
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Fegley DB, Holmes A, Riordan T, Faber CA, Weiss JR, Ma S, Batkai S, Pacher P, Dobolyi A, Murphy A, Sleeman MW, Usdin TB. Increased fear- and stress-related anxiety-like behavior in mice lacking tuberoinfundibular peptide of 39 residues. GENES BRAIN AND BEHAVIOR 2008; 7:933-42. [PMID: 18700839 DOI: 10.1111/j.1601-183x.2008.00432.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Tuberoinfundibular peptide of 39 residues (TIP39) is synthesized by two groups of neurons, one in the subparafascicular area at the caudal end of the thalamus and the other in the medial paralemniscal nucleus within the lateral brainstem. The subparafascicular TIP39 neurons project to a number of brain regions involved in emotional responses, and these regions contain a matching distribution of a receptor for TIP39, the parathyroid hormone 2 receptor (PTH2-R). We have now evaluated the involvement of TIP39 in anxiety-related behaviors using mice with targeted null mutation of the TIP39 gene (Tifp39). Tifp39(-/-) mice (TIP39-KO) did not significantly differ from wild-type (WT) littermates in the open field, light/dark exploration and elevated plus-maze assays under standard test conditions. However, the TIP39-KO engaged in more active defensive burying in the shock-probe test. In addition, when tested under high illumination or after restraint, TIP39-KO displayed significantly greater anxiety-like behavior in the elevated plus-maze than WT. In a Pavlovian fear-conditioning paradigm, TIP39-KO froze more than WT during training and during tone and context recall but showed normal fear extinction. Disruption of TIP39 projections to the medial prefrontal cortex, lateral septum, bed nucleus of the stria terminalis, hypothalamus and amygdala likely account for the fear- and anxiety-related phenotype of TIP39-KO. Current data support the hypothesis that TIP39 modulates anxiety-related behaviors following environmental provocation.
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Chan Wong E, Hatakeyama C, Robinson W, Ma S. IGF2/H19 DMR methylation in placentas conceived by IVF or ICSI. Fertil Steril 2008. [DOI: 10.1016/j.fertnstert.2008.07.1528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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282
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Sakian S, Furguson K, Minor A, Chan Wong E, Miller K, Ma S. The occurrence of Y-chromosome microdeletions in babies born through intracytoplasmic sperm injection (ICSI). Fertil Steril 2008. [DOI: 10.1016/j.fertnstert.2008.07.1529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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283
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Manolescu C, Grinberg M, Field C, Ma S, Shen S, Lee H, Wang Y, Granger A, Chen Q, McCaffrey J, Norwood D, Grinberg N. Studies of the Interactions of Amino Alcohols Using High Performance Liquid Chromatography with Crown Ether Stationary Phases. J LIQ CHROMATOGR R T 2008. [DOI: 10.1080/10826070802279285] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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284
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Zheng BJ, Du LY, Zhao GY, Lin YP, Sui HY, Chan C, Ma S, Guan Y, Yuen KY. Studies of SARS virus vaccines. Hong Kong Med J 2008; 14 Suppl 4:39-43. [PMID: 18708674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023] Open
Abstract
1. Intranasal vaccination using inactivated SARS coronavirus (SARS-CoV) vaccine with adjuvant can induce strong systemic (serum immunoglobulin [Ig] G) and respiratory tract local (tracheal-lung wash fluid IgA) antibody responses with neutralising activity. 2. RBD-Fc (protein-based vaccine) is able to induce effective neutralising antibodies able to provide protection from SARS-CoV infection in animal models. 3. A single dose of RBD-rAAV vaccination can induce adequate neutralising antibody against SARS-CoV infection. 4. Additional doses of vaccine increased the production of neutralising antibody 5-fold compared with a single dose. 5. RBD-rAAV vaccination provoked a prolonged antibody response with continually increasing levels of neutralising activity. 6. Intranasal vaccination with RBD-rAAV induced local IgA and systemic IgG neutralising antibodies and specific T-cell responses, able to protect against SARS-CoV infection in animal models. 7. When compared with the RBD-rAAV prime/boost vaccination, RBD-rAAV prime/RBD-peptide boost induced similar levels of Th1 and neutralising antibody responses that protected vaccinated mice from subsequent SARS-CoV challenges,but stronger Th2 and CTL responses. 8. Overall, our findings suggest that the inactivated vaccine, RBD-Fc and RBD-rAAV, can be further developed into effective and safe vaccines against SARS and that intranasal vaccination may be the preferred route of administration.
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Wang Y, Chen Y, Zhang Y, Wu S, Ma S, Hu S, Zhang L, Shao C, Li M, Gao Y. Differential ConA-Enriched Urinary Proteome in Rat Experimental Glomerular Diseases. ACTA ACUST UNITED AC 2008. [DOI: 10.4172/jpb.s1000165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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286
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Ma S, Krett N, Rosen ST. Correlation of differential expression of NALP7 and NALP11 with glucocorticoid sensitivity in multiple myeloma cell lines. J Clin Oncol 2008. [DOI: 10.1200/jco.2008.26.15_suppl.19516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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287
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Ma S, Xu Y, Deng Q, Yu X. Concomitant treatment of brain metastasis from non-small cell lung cancer with whole brain radiotherapy and gefitinib. J Clin Oncol 2008. [DOI: 10.1200/jco.2008.26.15_suppl.19135] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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288
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Ma S, Mifflin SW, Cunningham JT, Morilak DA. Chronic intermittent hypoxia sensitizes acute hypothalamic-pituitary-adrenal stress reactivity and Fos induction in the rat locus coeruleus in response to subsequent immobilization stress. Neuroscience 2008; 154:1639-47. [PMID: 18554809 DOI: 10.1016/j.neuroscience.2008.04.068] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Revised: 04/29/2008] [Accepted: 04/30/2008] [Indexed: 01/14/2023]
Abstract
Obstructive sleep apnea (OSA) is associated with several pathophysiological conditions, including hypertension, obesity, insulin resistance, hypothalamic-pituitary-adrenal (HPA) dysregulation, and other endocrine and metabolic disturbances comprising the "metabolic syndrome." Repeated episodes of hypoxia in OSA may represent a chronic intermittent stress, leading to HPA dysregulation. Alterations in HPA reactivity could then contribute to or exacerbate other pathophysiological processes. We showed previously that another metabolic stressor, chronic intermittent cold stress, enhanced noradrenergic facilitation of acute HPA stress reactivity. In this study, we investigated whether chronic intermittent hypoxia (CIH), a rat model for the arterial hypoxemia that accompanies OSA, similarly sensitizes the HPA response to novel acute stress. Rats were exposed to CIH (alternating cycles of normoxia [3 min at 21% O(2)] and hypoxia [3 min at 10% O(2)], repeated continuously for 8 h/day during the light portion of the cycle for 7 days). On the day after the final CIH exposure, there were no differences in baseline plasma adrenocorticotropic hormone (ACTH), but the peak ACTH response to 30 min acute immobilization stress was greater in CIH-stressed rats than in controls. Induction of Fos expression by acute immobilization stress was comparable following CIH in several HPA-modulatory brain regions, including the paraventricular nucleus, bed nucleus of the stria terminalis, and amygdala. Fos induction was attenuated in lateral hypothalamus, an HPA-inhibitory region. By contrast, acute Fos induction was enhanced in noradrenergic neurons in the locus coeruleus following CIH exposure. Thus, similar to chronic cold stress, CIH sensitized acute HPA and noradrenergic stress reactivity. Plasticity in the acute stress response is important for long-term adaptation, but may also contribute to pathophysiological conditions associated with states of chronic or repeated stress, such as OSA. Determining the neural mechanisms underlying these adaptations may help us better understand the etiology of such disorders, and inform the development of more effective treatments.
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Kirkpatrick G, Ferguson KA, Gao H, Tang S, Chow V, Yuen BH, Ma S. A comparison of sperm aneuploidy rates between infertile men with normal and abnormal karyotypes. Hum Reprod 2008; 23:1679-83. [DOI: 10.1093/humrep/den126] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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290
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Lee J, Ma S, Heng D, Chew SK, Hughes K, Tai ES. Hypertension, concurrent cardiovascular risk factors and mortality: the Singapore Cardiovascular Cohort Study. J Hum Hypertens 2008; 22:468-74. [DOI: 10.1038/jhh.2008.16] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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291
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Ferguson KA, Chow V, Ma S. Silencing of unpaired meiotic chromosomes and altered recombination patterns in an azoospermic carrier of a t(8;13) reciprocal translocation. Hum Reprod 2008; 23:988-95. [DOI: 10.1093/humrep/den013] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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292
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Czerwinski M, Ma S, Motakis D, Lee C. Economic analysis of open approach versus conventional methods of zygoma fracture repair. Plast Surg (Oakv) 2008. [DOI: 10.4172/plastic-surgery.1000571] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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293
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Wong EC, Ferguson KA, Chow V, Ma S. Sperm aneuploidy and meiotic sex chromosome configurations in an infertile XYY male. Hum Reprod 2007; 23:374-8. [DOI: 10.1093/humrep/dem377] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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294
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Rodriguez JA, Ma S, Liu P, Hrbek J, Evans J, Perez M. Activity of CeOx and TiOx Nanoparticles Grown on Au(111) in the Water-Gas Shift Reaction. Science 2007; 318:1757-60. [DOI: 10.1126/science.1150038] [Citation(s) in RCA: 808] [Impact Index Per Article: 47.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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295
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Ma S, Lee TK, Zheng BJ, Chan KW, Guan XY. CD133+ HCC cancer stem cells confer chemoresistance by preferential expression of the Akt/PKB survival pathway. Oncogene 2007; 27:1749-58. [PMID: 17891174 DOI: 10.1038/sj.onc.1210811] [Citation(s) in RCA: 590] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The recent discovery of cancer stem cells (CSCs) has played a pivotal role in changing our view of carcinogenesis and chemotherapy. Based on this concept, CSCs are responsible for the formation and growth of neoplastic tissue and are naturally resistant to chemotherapy, explaining why traditional chemotherapies can initially shrink a tumor but fails to eradicate it in full, allowing eventual recurrence. Recently, we identified a CSC population in hepatocellular carcinoma (HCC) characterized by their CD133 phenotype. However, the molecular mechanism by which it escapes conventional therapies remains unknown. Here, we examined the sensitivity of these cells to chemotherapeutic agents (doxorubicin and fluorouracil) and the possible mechanistic pathway by which resistance may be regulated. Purified CD133+ HCC cells isolated from human HCC cell line and xenograft mouse models survived chemotherapy in increased proportions relative to most tumor cells which lack the CD133 phenotype; the underlying mechanism of which required the preferential expression of survival proteins involved in the Akt/PKB and Bcl-2 pathway. Treatment of CD133+ HCC cells with an AKT1 inhibitor, specific to the Akt/PKB pathway, significantly reduced the expression of the survival proteins that was normally expressed endogenously. In addition, treatment of unsorted HCC cells with both anticancer drugs in vitro significantly enriched the CD133+ subpopulation. In conclusion, our results show that CD133+ HCC cells contribute to chemoresistance through preferential activation of Akt/PKB and Bcl-2 cell survival response. Targeting of this specific survival signaling pathway in CD133+ HCC CSCs may provide a novel therapeutic model for the disease.
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Kirkpatrick G, Wang EC, Ferguson K, Ma S. Interchromosomal effects in sperm of three heterozygous carriers of structural chromosomal rearrangements. Fertil Steril 2007. [DOI: 10.1016/j.fertnstert.2007.07.819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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297
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Low S, Chan FLF, Cutter J, Ma S, Goh KT, Chew SK. A national study of the epidemiology of pneumococcal disease among hospitalised patients in Singapore: 1995 to 2004. Singapore Med J 2007; 48:824-9. [PMID: 17728963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
INTRODUCTION Infections with Streptococcus pneumoniae cause significant morbidity and mortality. In this study, we describe the epidemiology of pneumococcal disease based on hospitalisation rates for all age groups in Singapore. This is important for evaluating prevention and control strategies of pneumococcal disease. METHODS We conducted a retrospective study of hospitalisation cases admitted to all public and private hospitals from 1995 to 2004. 4,275 hospitalisation records were extracted, based on the International Classification of Diseases, Ninth Revision (ICD-9) codes for pneumococcal disease. We analysed the demographics, type of pneumococcal disease, length of stay and case fatality of these cases. RESULTS Our study showed that the mean annual hospitalisation rate for pneumococcal disease was 10.9 per 100,000 population from 1995 to 2004. The mean annual hospitalisation rate was highest in the young and the elderly. CONCLUSION Baseline information on the epidemiology of pneumococcal disease is important for the formulation and evaluation of a national prevention and control programme.
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Avenel E, Favier A, Ma S, Mangematin V, Rieu C. Diversification and hybridization in firm knowledge bases in nanotechnologies. RESEARCH POLICY 2007. [DOI: 10.1016/j.respol.2007.02.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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299
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Blair MA, Ma S, Abou-Khalil B, Hedera P. Genetic variants in the IMPA2 gene do not confer increased risk of febrile seizures in Caucasian patients. Eur J Neurol 2007; 14:424-7. [PMID: 17388992 DOI: 10.1111/j.1468-1331.2007.01702.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Pathogenesis of febrile seizures (FS), causing the most common of types of seizures in children, remains unknown. Genetic factors appear to play a pivotal role and FS can be inherited as a monogenic or genetically complex disorder. Several risks factors have been proposed but many of the previously reported genetic associations were not replicated. Non-coding polymorphisms in the myo-inositol monophosphatase 2 gene (IMPA2) have been suggested as a susceptibility factor for FS in Japanese patients. It is unknown whether genetic variants in the same gene constitute a risk factor for FS in other ethnic groups because the frequency of FS is significantly higher in Japanese children than in Caucasian patients. We investigated the role of the IMPA2 gene in a cohort of 96 unrelated Caucasian subjects with a history of FS. We did not identify any significant differences in genotypes of cases and matched controls; no mutations or non-synonymous polymorphisms were detected in these individuals. Our data suggest that the genetic variants in the IMPA2 gene are not associated with a risk of FS in Caucasian patients and patients from various genetic groups are likely to have different genetic causes of FS.
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Ma S, Guan XY, Beh PSL, Wong KY, Chan YP, Yuen HF, Vielkind J, Chan KW. The significance of LMO2 expression in the progression of prostate cancer. J Pathol 2007; 211:278-85. [PMID: 17167821 DOI: 10.1002/path.2109] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
LIM domain only 2 (LMO2) proteins are important regulators in determining cell fate and controlling cell growth and differentiation. This study has investigated LMO2 expression in human prostatic tissue specimens, prostate cancer cell lines, and xenografts; and has assessed the possible role and mechanism of LMO2 in prostate carcinogenesis. Immunohistochemical analysis on a tissue microarray consisting of 91 human prostate specimens, including normal, prostatic hyperplasia, high-grade prostatic intraepithelial neoplasia, and invasive carcinoma, revealed that overexpression of LMO2 was significantly associated with advanced tumour stage, as measured by Gleason score (p = 0.012), as well as with the development of distant metastasis (p = 0.018). These data were supported by quantitative real-time PCR experiments, where LMO2 mRNA levels were found to be significantly higher in prostate tumour specimen than in normal epithelium (p = 0.037). The expression of LMO2 in cell lines and xenografts representing androgen-dependent (AD) and androgen-independent (AI) prostate cancer stages was further studied. Consistent with the in vivo data, LMO2 mRNA and protein were found to be overexpressed in the more aggressive AI cells (PC3, DU145, and AI CWR22 xenografts) compared with less aggressive AD cells (LNCaP and AD CWR22 xenografts). Furthermore, stable introduction of LMO2 into LNCaP cells conferred enhanced cell motility and invasiveness in vitro, accompanied by down-regulation of E-cadherin expression. Taken together, these findings provide the first evidence to support the hypothesis that LMO2 may play an important role in prostate cancer progression, possibly via repression of E-cadherin expression.
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