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result(s) for
"Lam, Sun Yee"
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Rescue of defective pancreatic secretion in cystic-fibrosis cells by suppression of a novel isoform of phospholipase C
by
Li, Jianmin
,
Tsang, Lai Ling
,
Jiang, Jian Li
in
Anions
,
Antisense DNA
,
Antisense Elements (Genetics)
2003
Cystic fibrosis is caused by mutations in the gene encoding an ion-transport protein, the cystic-fibrosis transmembrane conductance regulator (CFTR). Defective secretion of anions is the primary cause of many of the clinical manifestations of cystic fibrosis, including pancreatic insufficiency. We aimed to identify a molecular mechanism from which a new method to circumvent defective pancreatic secretion could be derived.
Multiple-human-tissue RT-PCR and semiquantitative RT-PCR analyses were used to examine gene expression. An antisense technique was used in conjunction with radioimmunoassay, Fura-2 spectrofluorometry, immunohisto-chemistry, and the short-circuit current technique (Ussing chamber) for elucidation of gene function and its application in rescuing defective pancreatic secretion.
We cloned a newly identified gene, NYD-SP27, which has structural similarity to an isoform of phospholipase C. NYD-SP27 was expressed endogenously in human pancreatic-duct cells and upregulated in cystic fibrosis. Suppression of NYD-SP27, by transfection of its antisense into human cystic-fibrosis pancreatic-duct cells, resulted in augmentation of phospholipase-C-coupled calcium-ion release and protein kinase C activity, improvement in the amount of mutated CFTR reaching the plasma membrane, and restoration of cAMP-activated pancreatic anion secretion.
NYD-SP27 exerts an inhibitory effect on phospholipase-C-coupled processes that depend on calcium ions and protein kinase C, including CFTR trafficking and function. Its upregulation in pancreatic-duct cells may reveal a previously unsuspected defect in cystic fibrosis contributing to pancreatic insufficiency, and thus represents a new target for pharmacological intervention in cystic fibrosis.
Journal Article
Understanding the Composition, Biosynthesis, Accumulation and Transport of Flavonoids in Crops for the Promotion of Crops as Healthy Sources of Flavonoids for Human Consumption
by
Cheng, Sau-Shan
,
Lo, Annie Wing-Yi
,
Xiao, Zhixia
in
anthocyanidins
,
Anthocyanins
,
Antioxidants
2020
Flavonoids are a class of polyphenolic compounds that naturally occur in plants. Sub-groups of flavonoids include flavone, flavonol, flavanone, flavanonol, anthocyanidin, flavanol and isoflavone. The various modifications on flavonoid molecules further increase the diversity of flavonoids. Certain crops are famous for being enriched in specific flavonoids. For example, anthocyanins, which give rise to a purplish color, are the characteristic compounds in berries; flavanols are enriched in teas; and isoflavones are uniquely found in several legumes. It is widely accepted that the antioxidative properties of flavonoids are beneficial for human health. In this review, we summarize the classification of the different sub-groups of flavonoids based on their molecular structures. The health benefits of flavonoids are addressed from the perspective of their molecular structures. The flavonoid biosynthesis pathways are compared among different crops to highlight the mechanisms that lead to the differential accumulation of different sub-groups of flavonoids. In addition, the mechanisms and genes involved in the transport and accumulation of flavonoids in crops are discussed. We hope the understanding of flavonoid accumulation in crops will guide the proper balance in their consumption to improve human health.
Journal Article
Generative adversarial networks for imputing missing data for big data clinical research
2021
Background
Missing data is a pervasive problem in clinical research. Generative adversarial imputation nets (GAIN), a novel machine learning data imputation approach, has the potential to substitute missing data accurately and efficiently but has not yet been evaluated in empirical big clinical datasets.
Objectives
This study aimed to evaluate the accuracy of GAIN in imputing missing values in large real-world clinical datasets with mixed-type variables. The computation efficiency of GAIN was also evaluated. The performance of GAIN was compared with other commonly used methods, MICE and missForest.
Methods
Two real world clinical datasets were used. The first was that of a cohort study on the long-term outcomes of patients with diabetes (50,000 complete cases), and the second was of a cohort study on the effectiveness of a risk assessment and management programme for patients with hypertension (10,000 complete cases). Missing data (missing at random) to independent variables were simulated at different missingness rates (20, 50%). The normalized root mean square error (NRMSE) between imputed values and real values for continuous variables and the proportion of falsely classified (PFC) for categorical variables were used to measure imputation accuracy. Computation time per imputation for each method was recorded. The differences in accuracy of different imputation methods were compared using ANOVA or non-parametric test.
Results
Both missForest and GAIN were more accurate than MICE. GAIN showed similar accuracy as missForest when the simulated missingness rate was 20%, but was more accurate when the simulated missingness rate was 50%. GAIN was the most accurate for the imputation of skewed continuous and imbalanced categorical variables at both missingness rates. GAIN had a much higher computation speed (32 min on PC) comparing to that of missForest (1300 min) when the sample size is 50,000.
Conclusion
GAIN showed better accuracy as an imputation method for missing data in large real-world clinical datasets compared to MICE and missForest, and was more resistant to high missingness rate (50%). The high computation speed is an added advantage of GAIN in big clinical data research. It holds potential as an accurate and efficient method for missing data imputation in future big data clinical research.
Trial registration
ClinicalTrials.gov
ID:
NCT03299010
; Unique Protocol ID: HKUCTR-2232
Journal Article
LINE-1 promotes tumorigenicity and exacerbates tumor progression via stimulating metabolism reprogramming in non-small cell lung cancer
2022
Background
Long Interspersed Nuclear Element-1 (LINE-1, L1) is increasingly regarded as a genetic risk for lung cancer. Transcriptionally active LINE-1 forms a L1-gene chimeric transcript (LCTs), through somatic L1 retrotransposition (LRT) or L1 antisense promoter (L1-ASP) activation, to play an oncogenic role in cancer progression.
Methods
Here, we developed Retrotransposon-gene fusion estimation program (ReFuse), to identify and quantify LCTs in RNA sequencing data from TCGA lung cancer cohort (
n
= 1146) and a single cell RNA sequencing dataset then further validated those LCTs in an independent cohort (
n
= 134). We next examined the functional roles of a cancer specific LCT (
L1-FGGY
) in cell proliferation and tumor progression in LUSC cell lines and mice.
Results
The LCT events correspond with specific metabolic processes and mitochondrial functions and was associated with genomic instability, hypomethylation, tumor stage and tumor immune microenvironment (TIME). Functional analysis of a tumor specific and frequent LCT involving
FGGY
(
L1-FGGY
) reveal that the arachidonic acid (AA) metabolic pathway was activated by the loss of
FGGY
through the
L1-FGGY
chimeric transcript to promote tumor growth, which was effectively targeted by a combined use of an anti-HIV drug (NVR) and a metabolic inhibitor (ML355). Lastly, we identified a set of transcriptomic signatures to stratify the LUSC patients with a higher risk for poor outcomes who may benefit from treatments using NVR alone or combined with an anti-metabolism drug.
Conclusions
This study is the first to characterize the role of L1 in metabolic reprogramming of lung cancer and provide rationale for L1-specifc prognosis and potential for a therapeutic strategy for treating lung cancer.
Trial registration
Study on the mechanisms of the mobile element
L1-FGGY
promoting the proliferation, invasion and immune escape of lung squamous cell carcinoma through the 12-LOX/Wnt pathway, Ek2020111. Registered 27 March 2020 ‐ Retrospectively registered.
Journal Article
Downregulation of chemokine (C-C motif) ligand 5 induced by a novel 8-hydroxyquinoline derivative (91b1) suppresses tumor invasiveness in esophageal carcinoma
by
Zhou, Yuanyuan
,
Lam, Alfred King-Yin
,
Huang, Wolin
in
chemokine (C-C motif) ligand 5
,
Chemokines
,
Chemotherapy
2024
Esophageal squamous cell carcinoma (ESCC) is a particularly aggressive form of cancer with high mortality. In the present study, a novel 8-hydroxyquinoline derivative (91b1) was investigated for its anticancer activities in ESCC along with its associated mechanisms. The in vitro cytotoxic effect of 91b1 were evaluated across five ESCC cell lines using MTS assay, with cisplatin serving as a comparative standard. Changes in gene expression profile were identified by cDNA microarray and further validated by qualitative PCR and immunostaining. Additionally, protein levels of the most notably downregulated target in archival ESCC samples were also studied. 91b1 demonstrated comparable anticancer effect with cisplatin. Notably, chemokine ligand 5 (Ccl5) was identified as the most substantially downregulated gene, with its suppression at both mRNA and protein expression in ESCC cells, exhibiting a dose-dependent manner. The recombinant human protein of CCL5 enhanced the invasion of ESCC cells using the Transwell assay. The upregulation of CCL5 protein was also detected in 50% of ESCC cell lines. CCL5 was also overexpressed in 76.9% of ESCC specimens. The overall results indicated that 91b1 could effectively induce anticancer effect on ESCC cells through downregulating CCL5 expression with suppression of tumor invasion. Overall, these findings suggested that 91b1 effectively inhibited ESCC cell proliferation and tumor invasion by downregulating CCL5 expression, highlighting its potential as a therapeutic agent for ESCC treatment.
Journal Article
Optimal blood pressure target in patients with uncomplicated hypertension: a target trial emulation study
2026
The limited real-world evidence on the clinical benefits of intensive blood pressure (BP) management demonstrated in randomised controlled trials has led to its poor adoption in primary care settings. Here we conducted a target trial emulation study on 118,271 patients with uncomplicated hypertension to evaluate the effectiveness and safety managed by intensive (below 130/80 mmHg) compared to standard (130-140/80-90 mmHg) BP targets using a territory-wide public healthcare database in Hong Kong. Patients in the intensive blood pressure target group were observed to incur a lower risk of hypertension related complications and all-cause mortality with no significant increased risk of the serious adverse events reported. The findings of this study provide evidence on the clinical benefits of an intensive BP management in real-world settings, supporting the adoption of a BP target of less than 130/80 mmHg in clinical guidelines for the treatment of adult patients with hypertension in primary care.
Journal Article
The impact of video gaming on cognitive functioning of people with schizophrenia (GAME-S): study protocol of a randomised controlled trial
2021
Background
Video gaming is a promising intervention for cognitive and social impairment in patients with schizophrenia. A number of gaming interventions have been evaluated in small-scale studies with various patient groups, but studies on patients with schizophrenia remain scarce and rarely include the evaluation of both clinical and neurocognitive outcomes. In this study, we will test the effectiveness of two interventions with gaming elements to improve cognitive and clinical outcomes among persons with schizophrenia.
Methods
The participants will be recruited from different outpatient units (e.g., outpatient psychiatric units, day hospitals, residential care homes). The controlled clinical trial will follow a three-arm parallel-group design: 1) cognitive training (experimental group, CogniFit), 2) entertainment gaming (active control group, SIMS 4), and 3) treatment as usual. The primary outcomes are working memory function at 3-month and 6-month follow-ups. The secondary outcomes are patients’ other cognitive and social functioning, the ability to experience pleasure, self-efficacy, and negative symptoms at 3-month and 6-month follow-ups. We will also test the effectiveness of gaming interventions on neurocognitive outcomes (EEG and 3 T MRI plus rs-fMRI) at a 3-month follow-up as an additional secondary outcome. Data will be collected in outpatient psychiatric services in Hong Kong. Participants will have a formal diagnosis of schizophrenia and be between 18 and 60 years old. We aim to have a total of 234 participants, randomly allocated to the three arms. A sub-sample of patients (
N
= 150) will be recruited to undergo an EEG. For neuroimaging assessment, patients will be randomly allocated to a subset of patients (
N
=126). We will estimate the efficacy of the interventions on the primary and secondary outcomes based on the intention-to-treat principle. Behavioural and EEG data will be analysed separately.
Discussion
The study will characterise benefits of gaming on patients’ health and well-being, and contribute towards the development of new treatment approaches for patients with schizophrenia.
Trial registration
ClinicalTrials.gov
NCT03133143
. Registered on April 28, 2017.
Journal Article
On-Treatment Improvement of MELD Score Reduces Death and Hepatic Events in Patients With Hepatitis B-Related Cirrhosis
by
Terry Cheuk-Fung Yip
,
Grace Lai-Hung Wong
,
Grace Chung-Yan Lui
in
Gastroenterology
,
Hepatitis
,
Hepatitis B
2018
ObjectivesAntiviral treatment modifies the natural history of chronic hepatitis B (CHB)-related cirrhosis as reflected by improving Model for End-Stage Liver Disease (MELD) score over time. We evaluated the impact of on-treatment change of MELD score on clinical outcomes in patients with CHB-related cirrhosis.MethodsCirrhotic CHB patients who received entecavir and/or tenofovir disoproxil fumarate for at least 6 months in Hong Kong between 2005 and 2016 were identified. The primary outcome was all-cause mortality; secondary outcomes were hepatocellular carcinoma (HCC), and hepatic events including ascites, spontaneous bacterial peritonitis, variceal bleeding, hepatorenal syndrome, hepatic encephalopathy, and liver transplantation.ResultsWe identified 1743 cirrhotic CHB patients. Their mean MELD score decreased from 12.3 ± 5.5 at baseline to 11.0 ± 4.7 at month 6. At a median (interquartile range) follow-up of 3.9 (1.9–6.0) years, 290 (16.6%) patients died; 201 (11.5%) developed HCC. Among 1140 patients without prior hepatic events, 150 (13.2%) developed hepatic events. Among 464 patients with baseline MELD score ≥15, the 6-year cumulative mortality was 72.8, 36.7, and 23.1% for unchanged or increased MELD score, 1–5 point improvement in MELD score, and >5 point improvement in MELD score at month 6, respectively (log-rank test, P < 0.001); the corresponding 6-year cumulative incidence of hepatic events was 52.7, 30.5, and 23.9% in the three subgroups (Gray’s test, P = 0.004). Patients with MELD score <15 at month 6 had lower risk of mortality and hepatic events (all P < 0.001).ConclusionsOn-treatment improvement of MELD score correlates with reduced risk of mortality and hepatic events in cirrhotic CHB patients.
Journal Article
Hepatitis Flare During Immunotherapy in Patients With Current or Past Hepatitis B Virus Infection
by
Wong, Vincent Wai-Sun
,
Mok, Tony Shu-Kam
,
Wong, Grace Lai-Hung
in
Administration, Oral
,
Aged
,
Alanine Transaminase - blood
2021
Immunotherapy has dramatically improved the survival of patients with advanced or metastatic malignancies. Recent studies suggest that immunotherapy may increase the risk of hepatitis, whereas it may also induce functional cure of chronic hepatitis B virus (HBV) infection. We evaluated the incidence of hepatitis flare, HBV reactivation, hepatitis B surface antigen (HBsAg) seroclearance or seroreversion in patients with current or past HBV infection who had received immunotherapy.
This was a territory-wide observational cohort study in Hong Kong. We identified patients through electronic medical records based on the prescriptions of immune checkpoint inhibitors from July 1, 2014, to December 31, 2019. Patients who were HBsAg positive or HBsAg negative with results for antibody to hepatitis B surface or core antigen (anti-HBs or anti-HBc) were included.
A total of 990 patients (397 HBsAg-positive, 593 HBsAg-negative with 482 anti-HBc and/or anti-HBs positive, and 111 both anti-HBc and anti-HBs negative) were identified. All of HBsAg-positive and 15.9% HBsAg-negative patients were put on oral antiviral treatment. Hepatitis flare (alanine aminotransferase >2 times of the upper limit of normal) occurred in 39.3% HBsAg-positive and 30.4% HBsAg-negative patients. High baseline alanine aminotransferase and combination of immunotherapy increased the risk of hepatitis. HBV reactivation (≥2 log increase in HBV DNA from baseline) occurred in 2 HBsAg-positive patients; HBsAg seroclearance and seroreversion was observed in 1 HBsAg-positive and 1 HBsAg-negative patient, respectively (<1%).
Hepatitis flare occurs in approximately 40% of HBsAg-positive patients and 30% of HBsAg-negative patients during immunotherapy. HBV reactivation, HBsAg seroclearance, and HBsAg seroreversion are rare. Current or past HBV infection has no impact on the emergence of hepatic flare associated with immunotherapy.
Journal Article
Cigarettes, heated tobacco products and dual use: exhaled carbon monoxide, saliva cotinine and total tobacco consumed by Hong Kong tobacco users
by
Chak, Kin Yeung
,
Leung, Lok Tung
,
Cheung, Yee Tak Derek
in
Adolescent
,
Adult
,
Breath Tests - methods
2024
BackgroundIndependent studies on exhaled carbon monoxide (CO) and saliva cotinine levels in regular heated tobacco product (HTP) users, and how they compare with conventional cigarette (CC) smokers, are lacking.MethodsA total of 3294 current users of CCs, HTPs or electronic cigarettes (ECs) from a household survey and a smoking hotspot survey were classified into seven groups: exclusive users of CCs, HTPs, ECs; dual users of CCs and HTPs, CCs and ECs, HTPs and ECs; and triple users. We measured exhaled CO level using the piCo Smokerlyzer (n=780) and saliva cotinine using NicAlert cotinine test strips (n=620). Among the seven groups, the differences in (1) CO and cotinine levels were examined using Kruskal-Wallis test, and (2) the average daily tobacco consumption in the past 30 days was examined using multivariable linear regression.ResultsBoth exclusive and dual users of CCs had a higher CO level than exclusive HTP or EC users (p<0.05). Exhaled CO levels were similar between HTP and EC users, as were saliva cotinine levels among the seven groups. Compared with exclusive CC users, those who also used HTPs or ECs smoked fewer CCs (CCs+HTPs: adjusted coefficient −2.79, 95% CI −3.90 to –1.69; CCs+ECs: −1.34, 95% CI −2.34 to –0.34), but consumed more tobacco sticks equivalent in total (2.79 (95% CI 1.61 to 3.96); 1.95 (95% CI 0.79 to 3.12)).ConclusionsHTP or EC use showed lower exhaled CO but similar saliva cotinine levels compared with CC use. Dual users of CCs and HTPs/ECs smoked fewer CCs than exclusive CC users, but consumed more tobacco in total.
Journal Article