14 results on '"Kai Man Li"'
Search Results
2. Oral antibiotics perturbation on gut microbiota after prostate biopsy
- Author
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Joseph Kai Man Li, Lynn Lin Wang, Becky Su Yan Lau, Ryan Tsz Hei Tse, Carol Ka Lo Cheng, Steven Chi Ho Leung, Christine Yim Ping Wong, Stephen Kwok Wing Tsui, Jeremy Yuen Chun Teoh, Peter Ka Fung Chiu, and Chi Fai Ng
- Subjects
antibiotics ,gut microbiota ,prostate biopsy ,bacteria ,fecal microbiota ,Microbiology ,QR1-502 - Abstract
IntroductionThe use of antibiotics may induce the changes in gut microbiota. Previous studies have shown conflicting results on whether the changed gut microbiota by antibiotics can be recovered. Our study aims to investigate whether the gut microbiota could be recovered after a single dose of oral co-amoxiclav before transrectal ultrasound-guided transperineal prostate biopsy (TPPBx) in 5 weeks’ time.MethodsFifteen patients with elevated serum prostate-specific antigen (PSA) were recruited to provide pre-antibiotic and post-antibiotic fecal samples. The V4 region of 16S rRNA was sequenced. Analysis was performed by QIIME2. Alpha- and beta-diversities were analyzed, as well as the differential enrichment by Linear discriminant analysis Effect Size (LEfSe) analysis.ResultsBoth the alpha- and beta-diversities of the pre- and post-antibiotic fecal samples were significantly different. Genera that are associated with alleviation of inflammation were enriched in the pre-antibiotic fecal samples, while the inflammation-associated genera were more enriched in the post-antibiotic fecal samples.ConclusionA single dose of oral co-amoxiclav before TPPBx could have led to a change of gut microbiota that cannot be recovered in 5 weeks' time. Microbiome studies on prostate cancer patients should be cautioned on the use of post-prostate biopsy fecal sampling. Further studies should be conducted for the impact on gut microbiome for TPPBx alone.
- Published
- 2022
- Full Text
- View/download PDF
3. Cost-effectiveness analysis of chromosomal microarray as a primary test for prenatal diagnosis in Hong Kong
- Author
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Claudia Ching Yan Chung, Kelvin Yuen Kwong Chan, Pui Wah Hui, Patrick Kwok Cheung Au, Wai Keung Tam, Samuel Kai Man Li, Gordon Ka Chun Leung, Jasmine Lee Fong Fung, Marcus Chun Yin Chan, Ho Ming Luk, Annisa Shui Lam Mak, Kwok Yin Leung, Mary Hoi Yin Tang, Brian Hon Yin Chung, and Anita Sik Yau Kan
- Subjects
Chromosomal microarray - prenatal diagnosis - cost effectiveness analysis - cost saving - Hong Kong ,Karyotyping ,Gynecology and obstetrics ,RG1-991 - Abstract
Abstract Background Chromosomal microarray (CMA) has been shown to be cost-effective over karyotyping in invasive prenatal diagnosis for pregnancies with fetal ultrasound anomalies. Yet, information regarding preceding and subsequent tests must be considered as a whole before the true cost-effectiveness can emerge. Currently in Hong Kong, karyotyping is offered free as the standard prenatal test while genome-wide array comparative genome hybridization (aCGH), a form of CMA, is self-financed. A new algorithm was proposed to use aCGH following quantitative fluorescent polymerase chain reaction (QF-PCR) as primary test instead of karyotyping. This study aims to evaluate the cost-effectiveness of the proposed algorithm versus the current algorithm for prenatal diagnosis in Hong Kong. Methods Between November 2014 and February 2016, 129 pregnant women who required invasive prenatal diagnosis at two public hospitals in Hong Kong were prospectively recruited. The proposed algorithm was performed for all participants in this demonstration study. For the cost-effectiveness analysis, cost and outcome (diagnostic rate) data were compared with that of a hypothetical scenario representing the current algorithm. Further analysis was performed to incorporate women’s willingness-to-pay for the aCGH test. Impact of government subsidies on the aCGH test was explored as a sensitivity analysis. Results The proposed algorithm dominated the current algorithm for prenatal diagnosis. Both algorithms were equally effective but the proposed algorithm was significantly cheaper (p ≤ 0.05). Taking into account women’s willingness-to-pay for an aCGH test, the proposed algorithm was more effective and less costly than the current algorithm. When the government subsidy reaches 100%, the maximum number of diagnoses could be made. Conclusion By switching to the proposed algorithm, cost saving can be achieved whilst maximizing the diagnostic rate for invasive prenatal diagnosis. It is recommended to implement aCGH as a primary test following QF-PCR to replace the majority of karyotyping for prenatal diagnosis in Hong Kong.
- Published
- 2020
- Full Text
- View/download PDF
4. Hemopatch to Prevent Lymphatic Leak after Robotic Prostatectomy and Pelvic Lymph Node Dissection: A Randomized Controlled Trial
- Author
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Jeremy Yuen-Chun Teoh, Alex Qinyang Liu, Violet Wai-Fan Yuen, Franco Pui-Tak Lai, Steffi Kar-Kei Yuen, Samson Yun-Sang Chan, Julius Ho-Fai Wong, Joseph Kai-Man Li, Mandy Ho-Man Tam, Peter Ka-Fung Chiu, Samuel Chi-Hang Yee, and Chi-Fai Ng
- Subjects
Cancer Research ,Oncology ,Hemopatch ,prostate cancer ,prostatectomy ,pelvic lymph node dissection ,lymphatic leak - Abstract
This study investigates whether the application of Hemopatch, a novel hemostatic patch, could prevent lymphatic leak after robotic-assisted radical prostatectomy (RARP) and bilateral pelvic lymph node dissection (BPLND). This is a prospective, single-center, phase III randomized controlled trial investigating the efficacy of Hemopatch in preventing lymphatic leak after RARP and BPLND. Participants were randomized to receive RARP and BPLND, with or without the use of Hemopatch, with an allocation ratio of 1:1. The primary outcome is the total drain output volume. The secondary outcomes include blood loss, operative time, lymph node yield, duration of drainage, drain output per day, hospital stay, transfusion and 30-day complications. A total of 32 patients were recruited in the study. The Hemopatch group had a significantly lower median total drain output than the control group (35 mL vs. 180 mL, p = 0.022) and a significantly lower drain output volume per day compared to the control group (35 mL/day vs. 89 mL/day, p = 0.038). There was no significant difference in the other secondary outcomes. In conclusion, the application of Hemopatch in RARP and BPLND could reduce the total drain output volume and the drain output volume per day. The use of Hemopatch should be considered to prevent lymphatic leakage after RARP and BPLND.
- Published
- 2022
- Full Text
- View/download PDF
5. Sectoral cancer detection and tolerability of freehand transperineal prostate biopsy under local anaesthesia
- Author
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Chi-Ho Leung, Jeremy Yuen-Chun Teoh, Ho-Fai Wong, Ka-Lun Lo, Suk-Yin Li, See-Ming Hou, Chi-Hang Yee, Siu-Fai Ma, Kittisak Sae-Lo, Peter Ka-Fung Chiu, Kai-Man Li, Chi-Fai Ng, and Sze-Wan Kwok
- Subjects
Image-Guided Biopsy ,Male ,Cancer Research ,medicine.medical_specialty ,Prostate biopsy ,Urology ,030232 urology & nephrology ,Cancer detection ,Perineum ,03 medical and health sciences ,Basal (phylogenetics) ,Prostate cancer ,0302 clinical medicine ,Prostate ,Biopsy ,medicine ,Humans ,Prospective Studies ,Aged ,medicine.diagnostic_test ,Urinary retention ,business.industry ,Biopsy, Needle ,Prostatic Neoplasms ,Middle Aged ,Prognosis ,medicine.disease ,medicine.anatomical_structure ,Oncology ,Tolerability ,030220 oncology & carcinogenesis ,Feasibility Studies ,medicine.symptom ,business ,Anesthesia, Local ,Follow-Up Studies - Abstract
BACKGROUND To investigate the feasibility of a freehand transperineal (TP) systematic prostate biopsy protocol under local anaesthesia (LA) and the value of different sectors in diagnosing prostate cancer (PCa). METHODS A total of 611 consecutive freehand TP biopsies under LA in 2 hospitals were prospectively evaluated. Cancer detection rate in each of the four different sectors (anterior, mid, posterior, basal) was recorded to evaluate the value of each sector. Procedure tolerability was assessed by pain score and complications were documented. RESULTS Systematic biopsies were performed in 556 out of 611 men with a median of 20 (IQR 12-24) biopsy cores taken. The median PSA was 9.9 (Inter-quartile range[IQR] 6.4-16.2) ng/mL, and 89.0% were first biopsies. All PCa and ISUP grade group (GG) ≥ 2 PCa (HGPCa) were diagnosed in 41.4% (230/556) and 28.2% (157/556) biopsies respectively. 77.0% HGPCa was diagnosed in ≥2 sectors. Single-sector HGPCa was predominantly found in anterior or posterior sector. Omitting base sector would have missed 1.5% (1/65) HGPCa out of the 219 cases with ≥24-core biopsies performed. Further omission of mid sector would have missed 3.1% (2/65) HGPCa and 7.4% (7/94) ISUP GG1 PCa (in which 3/7 involved 2 sectors). LA TP biopsy was well tolerated and the mean pain scores of the different steps of the procedure were between 1.9-3.1 (out of 10). Post-biopsy fever occurred in 0.3% of patients (2/611) and no sepsis was reported. The risk of urinary retention in men with ≥20 cores in ≥60 ml prostate was 7.8% (14/179), compared with 1.7% (7/423) in other groups (p
- Published
- 2020
6. Urine spermine and multivariable Spermine Risk Score predict high-grade prostate cancer
- Author
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Ryan Tsz Hei Tse, Peter Ka-Fung Chiu, Yan Ho Fung, Chun Hong Chan, Chi-Fai Ng, Ka-Leung Wong, Kai Man Li, Chi Ho Leung, Yim Ping Wong, Monique J. Roobol, Ka Lun Lo, Jeremy Yuen-Chun Teoh, and Urology
- Subjects
Male ,Cancer Research ,medicine.medical_specialty ,Multivariate analysis ,Urology ,030232 urology & nephrology ,Spermine ,Urine ,Risk Assessment ,03 medical and health sciences ,chemistry.chemical_compound ,Prostate cancer ,0302 clinical medicine ,SDG 3 - Good Health and Well-being ,Risk Factors ,Prostate ,Biomarkers, Tumor ,medicine ,Humans ,Prospective Studies ,Aged ,Framingham Risk Score ,medicine.diagnostic_test ,business.industry ,Prostatic Neoplasms ,Rectal examination ,Middle Aged ,medicine.disease ,medicine.anatomical_structure ,ROC Curve ,Oncology ,chemistry ,Quartile ,030220 oncology & carcinogenesis ,Neoplasm Grading ,business ,Follow-Up Studies - Abstract
Background: To investigate the role of urine spermine and Spermine Risk Score in prediction of high-grade prostate cancer (HGPCa, ISUP grade group ≥2). Methods: Nine hundred and five consecutive men with elevated PSA were prospectively recruited from two hospitals. Core analyses focused on consecutive men with PSA 4–20 ng/mL (n = 600). Pre-biopsy urine without prior prostatic massage was analyzed for spermine level with ultra-high performance liquid chromatography with triple quadrupole mass spectrometer (UPLC-MS/MS). The proportions of PCa and HGPCa were compared across different spermine ranges. Logistic regressions were used to form different models, and their performances were compared using area under curve (AUC) and decision curve analysis (DCA). Results: PCa and HGPCa were diagnosed in 30.8% (185/600) and 17.2% (103/600) men, respectively, and were significantly associated with lower urine spermine levels. Between the lowest and highest quartiles of spermine results, a threefold increase in PCa risk (49.3% vs. 16.7%) and 3.5-fold increase in ISUP grade group ≥2 PCa risk (31.3% vs. 8.7%) were observed. Multivariate analysis showed PSA, prostate volume (PV), digital rectal examination (DRE), and spermine, which were independent predictors for PCa and HGPCa, and a Spermine Risk Score with these factors achieved the highest AUC of 0.78 for PCa and 0.82 for HGPCa. At 90% sensitivity for HGPCa, 36.7% biopsies and 24.4% ISUP grade group 1 diagnoses could have been avoided, with a negative predictive value of 95.4%. DCA revealed net clinical benefit of the Spermine Risk Score. Internal validation with bootstrapping showed good discrimination and calibration. Conclusion: Urine spermine and Spermine Risk Score identified men at higher risk of HGPCa and reduced unnecessary biopsies.
- Published
- 2021
7. Oral antibiotics perturbation on gut microbiota after prostate biopsy.
- Author
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Kai Man Li, Joseph, Lynn Lin Wang, Su Yan Lau, Becky, Tse, Ryan Tsz Hei, Ka Lo Cheng, Carol, Chi Ho Leung, Steven, Yim Ping Wong, Christine, Kwok Wing Tsui, Stephen, Yuen Chun Teoh, Jeremy, Ka Fung Chiu, Peter, and Chi Fai Ng
- Subjects
GUT microbiome ,PROSTATE biopsy ,PROSTATE ,CALPROTECTIN ,ANTIBIOTICS ,FISHER discriminant analysis ,PROSTATE cancer patients ,PROSTATE-specific antigen - Abstract
Introduction: The use of antibiotics may induce the changes in gut microbiota. Previous studies have shown conflicting results on whether the changed gut microbiota by antibiotics can be recovered. Our study aims to investigate whether the gut microbiota could be recovered after a single dose of oral coamoxiclav before transrectal ultrasound-guided transperineal prostate biopsy (TPPBx) in 5 weeks' time. Methods: Fifteen patients with elevated serum prostate-specific antigen (PSA) were recruited to provide pre-antibiotic and post-antibiotic fecal samples. The V4 region of 16S rRNA was sequenced. Analysis was performed by QIIME2. Alpha- and beta-diversities were analyzed, as well as the differential enrichment by Linear discriminant analysis Effect Size (LEfSe) analysis. Results: Both the alpha- and beta-diversities of the pre- and post-antibiotic fecal samples were significantly different. Genera that are associated with alleviation of inflammation were enriched in the pre-antibiotic fecal samples, while the inflammation-associated genera were more enriched in the postantibiotic fecal samples. Conclusion: A single dose of oral co-amoxiclav before TPPBx could have led to a change of gut microbiota that cannot be recovered in 5 weeks' time. Microbiome studies on prostate cancer patients should be cautioned on the use of post-prostate biopsy fecal sampling. Further studies should be conducted for the impact on gut microbiome for TPPBx alone. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
8. En-bloc resection of bladder tumour as primary treatment for patients with non-muscle-invasive bladder cancer: routine implementation in a multi-centre setting
- Author
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Jeremy Yuen-Chun Teoh, Kai-Man Li, Chi-Fai Ng, Ka-Lun Lo, Nikhil Mayor, and Hugh Mostafid
- Subjects
Nephrology ,Male ,medicine.medical_specialty ,Multivariate analysis ,Urology ,Bladder tumour ,030232 urology & nephrology ,Logistic regression ,Cystectomy ,03 medical and health sciences ,0302 clinical medicine ,Postoperative Complications ,Urethra ,Internal medicine ,Medicine ,Humans ,Neoplasm Invasiveness ,Prospective Studies ,Multi centre ,Aged ,Aged, 80 and over ,Bladder cancer ,business.industry ,En bloc resection ,Middle Aged ,medicine.disease ,Surgery ,Treatment Outcome ,Urinary Bladder Neoplasms ,030220 oncology & carcinogenesis ,Female ,business ,Non muscle invasive - Abstract
To investigate the technical success rate and 30-day complications of en-bloc resection of bladder tumour (ERBT) upon routine implementation regardless of tumour size.This is a prospective, multi-centre, study on routine implementation of ERBT for patients with bladder tumours requiring transurethral surgery. Surgeons were allowed to cross over to conventional transurethral resection of bladder tumour (TURBT) when necessary. We performed an analysis for patients who had ERBT/TURBT as the definitive treatment. Study outcomes included the technical success rate of ERBT and 30-day complication rate. Multivariate logistic regression analysis was performed to investigate for predictors of a successful ERBT and factors associated with 30-day complications.A total of 135 patients were included in this study. The majority of the patients (80.0%) had bladder tumours of ≤ 3 cm. ERBT was successful in 99 patients, resulting in an overall technical success rate of 73.3%. When stratified according to tumour size, the technical success rates of ERBT were 94.3%, 82.2%, 75%, 84.3% and 29.6% for bladder tumour sizes of 1 cm, 1.01-2 cm, 2.01-3 cm, ≤ 3 cm and 3 cm respectively. Upon multivariate analysis, tumour size was the only significant factor predicting the success of ERBT (OR 0.920, 95% CI 0.882-0.960, p 0.001). Moreover, ERBT was not a significant factor associated with 30-day complications.EBRT achieved a good technical success rate for the majority of patients with bladder tumours ≤ 3 cm. Regardless of tumour size, EBRT-first approach was safe to implement into routine clinical practice.
- Published
- 2020
9. V14-03 TRANSPERINEAL MICROWAVE NEEDLE THERMOABLATION OF PROSTATE CANCER GUIDED BY MRI ULTRASOUND FUSION AND ORGAN BASED TRACKING TECHNOLOGY
- Author
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Sui Yan Lau, Chi-Fai Ng, Kai Man Li, Chi Hang Yee, Carmen C.M. Cho, Chi Kwok Chan, Jeremy Yuen-Chun Teoh, See Ming Hou, Ka Lun Lo, Suk Yin Crystal Li, Peter Chiu, and Sze Wan Kwok
- Subjects
Prostate cancer ,medicine.medical_specialty ,business.industry ,Urology ,Ultrasound ,medicine ,Radiology ,Tracking (particle physics) ,medicine.disease ,business ,Microwave - Published
- 2020
10. The cardiovascular risk factors in men with lower urinary tract symptoms
- Author
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Nicole M. Cheng, Cheuk-Hang Kwan, Simon S M Hou, Kai-Man Li, Jenny S Y Yip, Peter Ka-Fung Chiu, Chi-Fai Ng, Chi-Kwok Chan, Eddie Shu-Yin Chan, J. Wong, Jeremy Yuen-Chun Teoh, and Chi-Hang Yee
- Subjects
Blood Glucose ,Male ,Nephrology ,medicine.medical_specialty ,Urology ,Urinary system ,Prostatic Hyperplasia ,030232 urology & nephrology ,Malignancy ,Severity of Illness Index ,Body Mass Index ,03 medical and health sciences ,0302 clinical medicine ,Lower Urinary Tract Symptoms ,Risk Factors ,Lower urinary tract symptoms ,Internal medicine ,medicine ,Humans ,Aged ,Metabolic Syndrome ,Framingham Risk Score ,business.industry ,Age Factors ,Middle Aged ,Prostate-Specific Antigen ,medicine.disease ,Cholesterol ,Logistic Models ,Urinary tract surgery ,Cardiovascular Diseases ,030220 oncology & carcinogenesis ,Kallikreins ,business ,Body mass index ,Bladder stone - Abstract
It has been hypothesized that endothelial dysfunction and pelvic atherosclerosis may contribute to lower urinary tract symptoms (LUTS). We assessed the relationship between cardiovascular risk factors and LUTS severity in male patients presented to urology clinic. It is a cross-sectional study on patients who presented between 2013 and 2015 with LUTS. A total of 1176 male patients were encountered, and 966 were included for analysis after excluding patients with urinary tract malignancy, urethral stricture, bladder stone and history of urinary tract surgery. Cardiovascular risk factors including components of Framingham risk score, body mass index, uroflowmetry, International Prostate Symptoms Score, fasting blood glucose and serum prostate-specific antigen (PSA) were assessed. Correlation between Framingham risk score, cardiovascular risk factors and severity of LUTS was investigated. Multinomial logistic regression analysis showed that severe LUTS significantly associated with Framingham score (P = 0.008) and its components of total cholesterol (OR = 1.318; P = 0.010) and age (OR = 1.032; P = 0.006) compare with mild symptoms. Framingham risk score was found to correlate with storage symptoms (CC = 0.083; P
- Published
- 2018
11. Cost-effectiveness analysis of chromosomal microarray as a primary test for prenatal diagnosis in Hong Kong
- Author
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Anita Sik Yau Kan, Gordon K.C. Leung, Samuel Kai Man Li, Jasmine L.F. Fung, Patrick K. C. Au, Ho Ming Luk, Marcus C.Y. Chan, Claudia Ching Yan Chung, Brian H.Y. Chung, Mary Hoi Yin Tang, Kwok Yin Leung, Kelvin Y.K. Chan, P. W. Hui, Wai-Keung Tam, and Annisa Shui Lam Mak
- Subjects
medicine.medical_specialty ,Cost-Benefit Analysis ,Prenatal diagnosis ,lcsh:Gynecology and obstetrics ,Polymerase Chain Reaction ,03 medical and health sciences ,0302 clinical medicine ,Pregnancy ,Prenatal Diagnosis ,medicine ,Humans ,Medical physics ,Medical diagnosis ,lcsh:RG1-991 ,030304 developmental biology ,0303 health sciences ,Comparative Genomic Hybridization ,030219 obstetrics & reproductive medicine ,Maternal and child health ,business.industry ,Obstetrics and Gynecology ,Comparative Genome Hybridization ,Cost-effectiveness analysis ,Aneuploidy ,Cost savings ,Test (assessment) ,Karyotyping ,Chromosomal microarray - prenatal diagnosis - cost effectiveness analysis - cost saving - Hong Kong ,Hong Kong ,Female ,Public Health ,business ,Algorithms ,Research Article - Abstract
Background Chromosomal microarray (CMA) has been shown to be cost-effective over karyotyping in invasive prenatal diagnosis for pregnancies with fetal ultrasound anomalies. Yet, information regarding preceding and subsequent tests must be considered as a whole before the true cost-effectiveness can emerge. Currently in Hong Kong, karyotyping is offered free as the standard prenatal test while genome-wide array comparative genome hybridization (aCGH), a form of CMA, is self-financed. A new algorithm was proposed to use aCGH following quantitative fluorescent polymerase chain reaction (QF-PCR) as primary test instead of karyotyping. This study aims to evaluate the cost-effectiveness of the proposed algorithm versus the current algorithm for prenatal diagnosis in Hong Kong. Methods Between November 2014 and February 2016, 129 pregnant women who required invasive prenatal diagnosis at two public hospitals in Hong Kong were prospectively recruited. The proposed algorithm was performed for all participants in this demonstration study. For the cost-effectiveness analysis, cost and outcome (diagnostic rate) data were compared with that of a hypothetical scenario representing the current algorithm. Further analysis was performed to incorporate women’s willingness-to-pay for the aCGH test. Impact of government subsidies on the aCGH test was explored as a sensitivity analysis. Results The proposed algorithm dominated the current algorithm for prenatal diagnosis. Both algorithms were equally effective but the proposed algorithm was significantly cheaper (p ≤ 0.05). Taking into account women’s willingness-to-pay for an aCGH test, the proposed algorithm was more effective and less costly than the current algorithm. When the government subsidy reaches 100%, the maximum number of diagnoses could be made. Conclusion By switching to the proposed algorithm, cost saving can be achieved whilst maximizing the diagnostic rate for invasive prenatal diagnosis. It is recommended to implement aCGH as a primary test following QF-PCR to replace the majority of karyotyping for prenatal diagnosis in Hong Kong.
- Published
- 2019
12. Genomic instability in laminopathy-based premature aging
- Author
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Zhongjun Zhou, Xin Yuan Guan, Jian-Dong Huang, Baohua Liu, Pui Yin Chau, Yihai Cao, Wai Mui Tjia, Carlos López-Otín, Jianming Wang, David J. Chen, Hung-Fat Tse, Karl Tryggvason, Christopher J. Hutchison, Kathryn S.E. Cheah, Junjie Chen, Juan Cadiñanos, Kui Ming Chan, Alberto M. Pendás, Wen Deng, Kai Man Li, and Duanqing Pei
- Subjects
Premature aging ,Genome instability ,congenital, hereditary, and neonatal diseases and abnormalities ,DNA Repair ,Chromosomal Proteins, Non-Histone ,DNA repair ,DNA damage ,Bone Marrow Cells ,Laminopathy ,Biology ,Genomic Instability ,General Biochemistry, Genetics and Molecular Biology ,Progeroid syndromes ,Histones ,Mice ,medicine ,Animals ,Humans ,Protein Precursors ,Cellular Senescence ,Chromosome Aberrations ,Genetics ,integumentary system ,Intracellular Signaling Peptides and Proteins ,Membrane Proteins ,Metalloendopeptidases ,Nuclear Proteins ,Aging, Premature ,DNA ,General Medicine ,Fibroblasts ,Lamin Type A ,Phosphoproteins ,medicine.disease ,Progerin ,Mice, Mutant Strains ,Cell biology ,DNA-Binding Proteins ,Gamma Rays ,Rad51 Recombinase ,Tumor Suppressor p53-Binding Protein 1 ,Lamin ,DNA Damage - Abstract
Premature aging syndromes often result from mutations in nuclear proteins involved in the maintenance of genomic integrity. Lamin A is a major component of the nuclear lamina and nuclear skeleton. Truncation in lamin A causes Hutchinson-Gilford progerial syndrome (HGPS), a severe form of early-onset premature aging. Lack of functional Zmpste24, a metalloproteinase responsible for the maturation of prelamin A, also results in progeroid phenotypes in mice and humans. We found that Zmpste24-deficient mouse embryonic fibroblasts (MEFs) show increased DNA damage and chromosome aberrations and are more sensitive to DNA-damaging agents. Bone marrow cells isolated from Zmpste24-/- mice show increased aneuploidy and the mice are more sensitive to DNA-damaging agents. Recruitment of p53 binding protein 1 (53BP1) and Rad51 to sites of DNA lesion is impaired in Zmpste24-/- MEFs and in HGPS fibroblasts, resulting in delayed checkpoint response and defective DNA repair. Wild-type MEFs ectopically expressing unprocessible prelamin A show similar defects in checkpoint response and DNA repair. Our results indicate that unprocessed prelamin A and truncated lamin A act dominant negatively to perturb DNA damage response and repair, resulting in genomic instability which might contribute to laminopathy-based premature aging.
- Published
- 2005
13. Involvement of both endoplasmic reticulum and mitochondria in photokilling of nasopharyngeal carcinoma cells by the photosensitizer Zn–BC–AM
- Author
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Yan-Kin Lau, Ricky N S Wong, Wing-Nang Leung, Nai Ki Mak, Dolly P. Huang, Maria Li Lung, Chi K. Chang, and Kai-Man Li
- Subjects
Programmed cell death ,Metalloporphyrins ,Antineoplastic Agents ,Apoptosis ,Endoplasmic Reticulum ,Biochemistry ,symbols.namesake ,Calnexin ,Tumor Cells, Cultured ,Humans ,Endoplasmic Reticulum Chaperone BiP ,Caspase ,Pharmacology ,Photosensitizing Agents ,biology ,Endoplasmic reticulum ,Cytochrome c ,Nasopharyngeal Neoplasms ,Golgi apparatus ,Mitochondria ,Cell biology ,Enzyme Activation ,Photochemotherapy ,Caspases ,biology.protein ,symbols ,Unfolded protein response ,Calcium ,Subcellular Fractions - Abstract
Photodynamic therapy (PDT) is recently developed as an effective treatment for malignant disease. In PDT, the photosensitizer eradicates tumour by induction of apoptosis. In this study, we investigated the mechanistic actions of a recently developed second generation photosensitizer, Zn-BC-AM, on nasopharyngeal carcinoma (NPC) cells. Zn-BC-AM was found to localize in the mitochondria, endoplasmic reticulum (ER), and golgi body. Photoactivation of Zn-BC-AM loaded NPC cells resulted in a rapid collapse of mitochondrial membrane potential (Deltapsim) (15 min), followed by the release of cytochrome c (1 h), and activation of caspases-9 and -3 (4 h). Expression of ER chaperones Bip/Grp78 and Grp94, and ER resident lectin-like chaperone calnexin (CNX) was also enhanced in PDT-stressed NPC cells. Caspase-12, an important caspase involved in ER stress-induced apoptosis, was also activated. Inhibition of Ca2+ uptake into mitochondria by ruthenium red (RR) or loading the cells with EGTA-AM, an agent that buffers intracellular Ca2+ released from ER, resulted in a significant reduction of Zn-BC-AM PDT-induced cell death. These observations suggest that both ER and mitochondria are the subcellular targets of Zn-BC-AM. Effective activation of ER- and mitochondria-mediated apoptotic pathways is responsible for Zn-BC-AM PDT-induced NPC cell death.
- Published
- 2004
14. Genomic instability in laminopathy-based premature aging.
- Author
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Baohua Liu, Jianming Wang, Kui Ming Chan, Wai Mui Tjia, Wen Deng, Xinyuan Guan, Jian-dong Huang, Kai Man Li, Pui Yin Chau, Chen, David J., Duanqing Pei, Pendas, Alberto M., Cadiñanos, Juan, López-Otín, Carlos, Hung Fat Tse, Hutchison, Chris, Junjie Chen, Yihai Cao, Cheah, Kathryn S. E., and Tryggvason, Karl
- Subjects
AGING ,PROTEINS ,PROGERIA ,CHROMOSOMES ,BONE marrow cells - Abstract
Premature aging syndromes often result from mutations in nuclear proteins involved in the maintenance of genomic integrity. Lamin A is a major component of the nuclear lamina and nuclear skeleton. Truncation in lamin A causes Hutchinson-Gilford progerial syndrome (HGPS), a severe form of early-onset premature aging. Lack of functional Zmpste24, a metalloproteinase responsible for the maturation of prelamin A, also results in progeroid phenotypes in mice and humans. We found that Zmpste24-deficient mouse embryonic fibroblasts (MEFs) show increased DNA damage and chromosome aberrations and are more sensitive to DNA-damaging agents. Bone marrow cells isolated from Zmpste24
−/− mice show increased aneuploidy and the mice are more sensitive to DNA-damaging agents. Recruitment of p53 binding protein 1 (53BP1) and Rad51 to sites of DNA lesion is impaired in Zmpste24−/− MEFs and in HGPS fibroblasts, resulting in delayed checkpoint response and defective DNA repair. Wild-type MEFs ectopically expressing unprocessible prelamin A show similar defects in checkpoint response and DNA repair. Our results indicate that unprocessed prelamin A and truncated lamin A act dominant negatively to perturb DNA damage response and repair, resulting in genomic instability which might contribute to laminopathy-based premature aging. [ABSTRACT FROM AUTHOR]- Published
- 2005
- Full Text
- View/download PDF
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