Publications by authors named "Wing Tat Poon"

Article Synopsis
  • The study aimed to see how the Prostate Health Index (PHI) affects clinical decisions for men with PSA levels between 4-10 ng/mL and normal digital rectal exams in Hong Kong public hospitals from 2016 to 2017.
  • Of 2828 patients followed for 2 years, 82% showed low PHI risk scores (under 35), leading 83% of those with elevated PSA to choose against biopsy, while higher PHI scores correlated with increased detection of high-grade prostate cancer.
  • The conclusion suggests that using PHI in clinical decisions helped reduce unnecessary biopsies and improved the detection of significant prostate cancer compared to traditional PSA methods.
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Familial hypercholesterolemia (FH) is a prevalent but often underdiagnosed monogenic disorder affecting lipoprotein metabolism, and genetic testing for FH has not been widely conducted in Asia in the past. In this cross-sectional study of 31 probands (19 adults and 12 children) and an addition of 15 individuals (12 adults and 3 children), who underwent genetic testing and cascade screening for FH, respectively, during the period between February 2015 and July 2023, we identified a total of 25 distinct variants in 71.0% unrelated probands.

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Purpose: 5-alpha reductase inhibitor (5ARI) reduces prostate-specific antigen (PSA) by half but its effect on prostate health index (phi) is unknown. This study aims to investigate this effect and to enable accurate interpretation of phi in men with elevated PSA and on 5ARI.

Methods: This is a prospective study evaluating the effect of finasteride on PSA, free PSA (fPSA), [ - 2]proPSA (p2PSA) and phi at 6 and 12 moths in men with PSA 4-20 ng/mL, no prior 5ARI use, and one negative prostate biopsy within 6 months before recruitment.

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Background: Mucolipidosis alpha/beta is an inborn error of metabolism characterized by deficiency of GlcNAc-1-phosphotransferase, in which essential alpha/beta subunits are encoded by the GNPTAB gene. The autosomal recessive condition is due to disruptions of hydrolase mannose 6-phosphate marker generation, defective lysosomal targeting and subsequent intracellular accumulation of non-degraded material. Clinical severity depends on residual GlcNAc-1-phosphotransferase activity, which distinguishes between the milder type III disease and the severe, neonatal onset type II disease.

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Thiopurines are clinically useful in the management of diverse immunological and malignant conditions. Nevertheless, these purine analogues can cause lethal myelosuppression, which may be prevented by prospective testing for variants in the thiopurine S-methyltransferase () and, in East Asians, Nudix hydrolase 15 () genes. Two single-tube, tetra-primer amplification refractory mutation system polymerase chain reaction (ARMS-PCR) assays were developed to genotype the common loss-of-function variants c.

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The measurement of urine catecholamine and metanephrine concentrations is important for biochemical screening and diagnosis of pheochromocytoma. The goal of this work was to develop a simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for determining catecholamines and metanephrines in urine to replace an existing liquid chromatographic method using electrochemical detection. Urine samples were prepared using Oasis weak-cation-exchange cartridges.

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Thiopurine intolerance and treatment-related toxicity, such as fatal myelosuppression, is related to non-function genetic variants encoding thiopurine S-methyltransferase (TPMT) and Nudix hydrolase 15 (NUDT15). Genetic testing of the common variants NUDT15:NM_018283.2:c.

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Charcot-Marie-Tooth disease (CMT) is a common inherited peripheral neuropathy affecting up to 1 in 1214 of the general population with more than 60 nuclear genes implicated in its pathogenesis. Traditional molecular diagnostic pathways based on relative prevalence and clinical phenotyping are limited by long turnaround time, population-specific prevalence of causative variants and inability to assess multiple co-existing variants. In this study, a CMT gene panel comprising 27 genes was used to uncover the pathogenic mutations in two index patients.

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Hyperekplexia is a rare neurologic disorder, characterized by excessive startle response to unexpected stimuli. There are 3 cardinal features: generalized stiffness immediately after birth that normalizes during the first year of life; excessive startle reflex to unexpected (particularly auditory) stimuli; and a short period of generalized stiffness following the startle response while patient cannot elicit voluntary movements. Awareness of this condition will avoid misdiagnosis of disorders like epilepsy.

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Aim: Inborn errors of metabolism (IEM) are an unpopular and difficult subject and most clinicians are unfamiliar with them. Although chemical pathologists have a long-standing practice in advising test strategy and result interpretation especially from primary care, such consultations are usually informal, unstructured and those related to IEM are infrequently requested. This study aims to provide a formal electronic consultation service and to apply tandem mass spectrometry-based dried blood spot metabolic screening (DBSM) as a rapid first-line test for patients suspected of IEM.

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Background: Aconite poisoning is a severe, life-threatening poisoning related to the use of traditional Chinese medicine (TCM). Despite current legislation, repeated poisoning cases are steadily encountered.

Objective: The aim of the study was to summarize the clinical features and to elucidate the causative and contributory factors leading to aconite poisoning.

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Proopiomelanocortin (POMC) is the polypeptide precursor of several biologically active melanocortin peptides that have important roles in the regulation of food intake and energy homeostasis, adrenal steroidogenesis, melanocyte stimulation, and immune modulation. Mutation of the POMC gene has been associated with adrenal insufficiency, early-onset obesity, and red hair pigmentation. We describe an Indian boy with secondary hypocortisolism, hyperphagia, early-onset obesity, and skin pigmentation problem.

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Influenza-associated encephalopathy (IAE) is a potentially fatal neurological complication of influenza infection usually in the presence of high and persistent fever. Thermolabile carnitine palmitoyltransferase II enzyme (CPT-II) predisposes IAE, so far only described in Japanese. As the genetic origins of Japanese and Chinese are alike, similar genetic risk factors in CPT-II are expected.

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Background: Polymorphisms in the major histocompatibility complex (MHC) and non-MHC genes were recently reported to be associated with persistent hepatitis B virus (HBV) infection and host response to hepatitis B vaccine in Asian populations. We aimed to confirm the associations in Chinese population and develop a non-invasive screening method for the risk loci.

Methods: We genotyped 2 risk alleles on the MHC loci, HLA-DPA1 (rs3077) and HLA-DPB1 (rs9277535), and 1 risk allele near a non-MHC gene, FOXP1 (rs6789153) using high-resolution melting curve analysis.

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Prolonged intake of aristolochic acid (AA) has been shown to be associated with the development of certain renal disorders. Renal tubular atrophy and interstitial fibrosis are the early symptoms of AA nephropathy. The symptoms were observed in rats that were dosed with AA at a dosage of 10 mg/kg/day for 1 month.

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Objective: To evaluate an algorithmic approach involving a multidisciplinary team for causality assessment of suspected herb-induced liver injury (HILI) cases and to compare the causality score using this multidisciplinary approach and Roussel Uclaf Causality Assessment Method (RUCAM).

Methods: A team consisting of hepatologist, clinical toxicologist, analytical toxicologist, and Chinese medicine (CM) pharmacist was formed to do causality assessment based on a protocol for suspected HILI cases. The likelihood of the diagnosis of individual case was first assessed systematically by a hepatologist and clinical toxicologist independently after collecting information about four aspects: (1) clinical course, (2) exclusion of alternative causes, (3) quality of the prescription and herbal product by examining the CM prescriptions and analysis of biological and herb samples, (4) scientific support on comprehensive literature review on English and Chinese medical database, and subsequently concluded in a consensus meeting held by the multidisciplinary team.

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Context: Sibutramine, or its structurally related analogs, is often found as an adulterant in proprietary herbal slimming products in Hong Kong. A few solitary case reports of sibutramine-associated psychosis have been published since 2000. As the only tertiary referral center for clinical toxicology analysis in Hong Kong, we noticed that psychosis was an unusually common feature in patients taking "herbal slimming products" adulterated with sibutramine or its structurally related analogs over the past 5 years.

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Fructus Psoraleae (FP) is used by herbalists for the treatment of postmenopausal osteoporosis, vitiligo, and psoriasis. It is used alone, or in combination with other herbs, in some countries in the form of proprietary medicine. It is recognized as one of the emerging hepatotoxins and here we report three cases of acute hepatitis after exposed to FP and its related proprietary medicine.

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A sensitive high-performance liquid chromatography method with fluorescence detection (HPLC-FLD) for the determination of DNA adducts induced by nephrotoxic and carcinogenic aristolochic acid (AA) is presented. The DNA adduct of AAII (dA-AAII) was synthesized by in vitro incubation, purified by preparative HPLC, characterized using fluorescence spectroscopy and high-resolution mass spectrometry, and was used as the biomarker for AA exposure in rats. The developed HPLC-FLD method was validated and applied for the determination of dA-AAII in rat kidney tissues.

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Aristolochic acid (AA), derived from the herbal genus Aristolochia and Asarum, has recently been shown to be associated with the development of nephropathy. Upon enzyme activation, AA is metabolized to the aristolactam-nitrenium ion intermediate, which reacts with the exocyclic amino group of the DNA bases via an electrophilic attack at its C7 position, leading to the formation of the corresponding DNA adducts. The AA-DNA adducts are believed to be associated with the nephrotoxic and carcinogenic effects of AA.

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Introduction: In Hong Kong, Chinese medicine is popular and coexists with orthodox Western medicine. Despite a long history of use, many herbs have not been submitted to rigorous scientific testing and there are reports of hepatotoxicity. We describe a woman who developed acute hepatitis after drinking an herbal remedy containing Teucrium viscidum.

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A new herbal health product marketed for enhancing erectile function, namely Power58 Platinum, was purchased over-the-counter in Hong Kong. The product was tested for adulteration with sildenafil, tadalafil, and vardenafil as well as their structurally modified analogues. A new analogue of vardenafil, in which the N-ethylpiperazine ring and the sulphonyl group were removed from the vardenafil structure, was identified in the product.

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Thrombotic thrombocytopenic purpura (TTP) is a rare but potentially fatal disease in childhood. The association of microangiopathic hemolytic anemia, schistocytes, and thrombocytopenia without fever, neurologic, and renal involvement is sufficient to suspect TTP at an early stage for prompt plasma infusion or exchange therapy. TTP has been increasingly described especially in association with systemic lupus erythematosus (SLE).

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A HPLC method was developed and applied to analyze aristolochic acids (AA-I and AA-II) in Chinese medicinal herbs. The herb samples were extracted by using ultrasonication with the extraction efficiency of better than 82%. Extracts were then filtered and injected onto a C18 column eluting under a gradient program using methanol and water-containing 0.

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