C A van Hasselt

Prince of Wales Hospital, Hong Kong, Chiu-lung, Kowloon City, Hong Kong

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Publications (274)534.09 Total impact

  • International Journal of Disability Development and Education 08/2015; DOI:10.1080/1034912X.2015.1065960 · 0.59 Impact Factor
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    ABSTRACT: Context: The incidence of papillary thyroid cancer (PTC) shows a predominance in females with a male:female ratio of 1:3 and none of known risk factors are associated with gender difference. Increasing evidence indicating a role of estrogen in thyroid tumorigenesis, but the mechanism involved remains largely unknown. Objective: This study aimed to assess the contribution of autophagy to estrogen receptor α (ERα)-mediated growth of PTC. Design: The expression of ERα in thyroid tissue of patients with PTC tissues was analyzed. Cell viability, proliferation and apoptosis were evaluated after chemical and genetic inhibition of autophagy. Autophagy in PTC cell lines BCPAP and BCPAP-ERα was assessed. Results: ERα expression was increased in PTC tissues compared with the adjacent non-tumor tissues. Estrogen induced autophagy in an ERα-dependent manner. Autophagy induced by estrogen/ERα is associated with generation of reactive oxygen species, activation of extracellular-signal-regulated kinases (ERK1/2) and the survival/growth of PTC cells. Chemical and genetic inhibition of autophagy dramatically decreased tumor cell survival and promoted apoptosis, confirming the positive role of autophagy in the growth of PTC. Conclusions: ERα contributes to the growth of PTC by enhancing an important pro-survival catabolic process, autophagy, in PTC cells. The inhibition of autophagy promotes apoptosis, implicating a novel strategy for the treatment of ERα-positive PTC.
    Journal of Clinical Endocrinology &amp Metabolism 01/2015; 100(4):jc20143257. DOI:10.1210/jc.2014-3257 · 6.21 Impact Factor
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    ABSTRACT: Foxp3+ regulatory T cells (Tregs) in lymphocytes facilitate the thyroid tumor growth and invasion. Very limited information is available on Foxp3 expression in thyroid cancer cells and its function is totally unknown. This study demonstrated that Foxp3 expression was increased in thyroid cancer cells. Inhibition of Foxp3 decreased cell proliferation and migration, but increased apoptosis, suggesting a positive role of Foxp3 in cancer growth. Interestingly, Foxp3 inhibition enhanced PPARγ expression and activity. In addition, Foxp3 inhibition downregulated NF-κB subunit p65 and cyclin D1 but upregulated caspase-3 levels. These molecular changes are in line with Foxp3 shRNA-mediated alteration of cell functions. Collectively, our study demonstrates that thyroid cancer cells express a high level of functional Foxp3 and that the inhibition of the Foxp3 suppresses the proliferation and migration but promotes apoptosis, suggesting that targeting Foxp3 in thyroid cancer cells may offer a novel therapeutic option for thyroid cancer.
    Molecular and Cellular Endocrinology 10/2014; 399(C). DOI:10.1016/j.mce.2014.10.006 · 4.41 Impact Factor
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    ABSTRACT: Endoscopic base of skull surgery has been growing in acceptance in the recent past due to improvements in visualisation and micro instrumentation as well as the surgical maturing of early endoscopic skull base practitioners. Unfortunately, these demanding procedures have a steep learning curve. A physical simulation that is able to reproduce the complex anatomy of the anterior skull base provides very useful means of learning the necessary skills in a safe and effective environment. This paper aims to assess the ease of learning endoscopic skull base exposure and drilling techniques using an anatomically accurate physical model with a pre-existing pathology (i.e., basilar invagination) created from actual patient data. Five models of a patient with platy-basia and basilar invagination were created from the original MRI and CT imaging data of a patient. The models were used as part of a training workshop for ENT surgeons with varying degrees of experience in endoscopic base of skull surgery, from trainees to experienced consultants. The surgeons were given a list of key steps to achieve in exposing and drilling the skull base using the simulation model. They were then asked to list the level of difficulty of learning these steps using the model. The participants found the models suitable for learning registration, navigation and skull base drilling techniques. All participants also found the deep structures to be accurately represented spatially as confirmed by the navigation system. These models allow structured simulation to be conducted in a workshop environment where surgeons and trainees can practice to perform complex procedures in a controlled fashion under the supervision of experts.
    Archiv für Klinische und Experimentelle Ohren- Nasen- und Kehlkopfheilkunde 10/2014; 272(3). DOI:10.1007/s00405-014-3300-3 · 1.55 Impact Factor
  • Willis S Tsang · John K Woo · C Andrew van Hasselt ·
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    ABSTRACT: The most common sites of fish bone impaction are the tonsils, tonsillar pillars, tongue base, valleculae, and piriform fossa. Impaction in the supraglottic area is extremely uncommon.
    Ear, nose, & throat journal 10/2014; 93(10-11):452. · 1.00 Impact Factor
  • Stanley Ching Nam Ha · Dennis Lip Yen Lee · Victor James Abdullah · Charles Andrew van Hasselt ·
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    ABSTRACT: Background: The present study validates and evaluates the sensitivity and specificity of four internationally popular questionnaires, translated into Chinese, for assessing suspected obstructive sleep apnea (OSA) patients, namely, the Berlin questionnaire, the ASA checklist, the STOP questionnaire and the STOP-BANG questionnaire. Their predictive values in OSA risks in patients presenting with OSA symptoms are examined. Questionnaires may be helpful in prioritizing polysomnography (PSG) and in treatment for the more severe cases. Methods: All patients attending our sleep laboratory for overnight PSG were recruited. They were asked to complete three questionnaires (Berlin, ASA checklist and STOP) 2 weeks before and on the same night as the PSG. STOP-BANG questionnaire, an extended STOP with demographic data, 'B'-body mass index (BMI), 'A'-age, 'N'-neck circumference and 'G'-gender was completed by our technologists using the patient's completed STOP. Results: A number of 141 patients were recruited. The sensitivities and specificities for STOP-BANG with cutoffs at PSG's RDI=5, RDI=15 and RDI=30 were 81% to 86% and 34% to 57%, respectively. The high-risk group patients identified by STOP-BANG had significantly higher respiratory disturbance index and lower minimum oxygen saturation than the low-risk group patients. Conclusion: Among the four questionnaires studied, STOP-BANG, with only eight questions and the highest sensitivity, is the best questionnaire of the four for OSA screening. This can potentially assist in prioritizing PSG and can be helpful in clinical or self-evaluation by the general public.
    Sleep And Breathing 09/2014; 18(4). DOI:10.1007/s11325-013-0889-1 · 2.48 Impact Factor
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    ABSTRACT: Purpose: This study aimed at investigating (1) tone perception development among typically-developing Cantonese speakers and (2) the hierarchy of tone perception difficulty among the 15 tone contrasts. Method: Two-hundred typically-developing children aged 3-10 and a group of 25 normal hearing adults were recruited. They were tested on a pool of 75-item calibrated recorded speech signals. Participants responded to each stimulus by pointing at the corresponding picture displayed on a computer screen from a choice of four. Result: There was a gradual increase in tone perception accuracy from children aged 3-6. After age 6, tone perception accuracy was similar to adults with an average error rate of 3-8%. The two tone contrasts that listeners consistently found difficult to distinguish were T2T5 (high-rising vs low-rising) and T3T6 (mid-level vs low-level). In addition, all children groups also showed difficulty in T4T6 identification (low-falling vs low-level). Conclusion: Tone perception is not error-free even among native Cantonese-speaking adults. Overall tone identification performance improved steadily from age 3 to age 6. Based on the participants' performance, a three-tier set of tone groups, with an increasing level of difficulty for identification, is proposed for rehabilitation purposes. These tone groups are (1) Easy: T1T2, T1T3, T1T4, T1T5, T1T6, and T2T3, (2) Medium: T2T4, T2T6, T3T4, and T4T5, and (3) Hard: T2T5, T3T5, T3T6, T4T6, and T5T6.
    International Journal of Speech-Language Pathology 04/2014; 17(1). DOI:10.3109/17549507.2014.898096 · 1.24 Impact Factor
  • Alexander C Vlantis · Eddy W Y Wong · C Andrew van Hasselt ·

    Otolaryngology Head and Neck Surgery 11/2013; 150(1). DOI:10.1177/0194599813512104 · 2.02 Impact Factor
  • Jonathan Paul Speelman · Alane Kosanovich Cahalane · Charles Andrew Van Hasselt ·
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    ABSTRACT: Background: A novel live porcine model replicated the endoscopic surgical field of a carotid arterial injury of the human skull base. Hemostatic techniques were applied to jugular venous and carotid arterial injuries, including muscle patches, hemoclips, and aneurysm clips. Doppler imaging distal to the injury assessed flow through the repaired vessel. Materials and methods: External jugular veins, and internal carotid arteries isolated from seven live anesthetized 100 kg pigs, were placed into a sinus model otorhino neuro trainer for visualization via an endoscopic nasal approach. Vessels were systematically injured and repaired, and Doppler measurements were made to assess flow through the vessels before injury and following repair. Results and conclusions: Blood pressures were maintained within physiological ranges, despite blood losses of up to 4.5 l. Venous injuries were repaired using Floseal, hemoclips, and aneurysm clips, while arterial injuries were repaired with muscle patches and aneurysm clips. Blood flow remained in all vessels after repair. This porcine model was effective for demonstration of arterial and venous injuries during endoscopic skull base surgery. Crushed muscle patch was effective for arterial injuries of 3 mm, and the aneurysm clips for injuries of 5 mm. Jugular venous injuries of 3 mm were repaired using Floseal, 5 mm using hemoclips, and 6 mm using aneurysm clips. Doppler imaging was a noninvasive means of demonstrating ongoing flow through injured and repaired vessels. The model represents a valuable training tool with the potential to train endoscopic skull base teams the skills required to manage an internal carotid artery injury.
    Journal of Investigative Surgery 08/2013; 26(5). DOI:10.3109/08941939.2013.797054 · 1.16 Impact Factor
  • Kwong Lun Lai · Victor Abdullah · Kwan Shun Ng · Ngai Sheung Fung · C Andrew van Hasselt ·
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    ABSTRACT: Sinus histiocytosis with massive lymphadenopathy or Rosai–Dorfman disease (RDD) is a rare benign disease with nodal and extranodal involvement. Herein, we report 3 cases in which the patients presented with nasal masses. In addition, 2 of the 3 patients had subglottic lesions. Only 2 of the 3 patients had cervical lymphadenopathy, which is the commonest presentation of RDD. Histopathology via fine-needle aspiration cytology (FNAC) or open biopsy is required for diagnosis. Emperipolesis with S-100 immunohistochemical staining is characteristic. The disease runs a benign course and the literature reports that treatment can vary from steroids, to cytotoxic chemotherapy to radiotherapy with variable outcomes. Surgical intervention may be necessary for airway protection. RDD is self-limiting, but can sometimes be a life-threatening condition. Treatment should be tailored to the individual patient. © 2011 Wiley Periodicals, Inc. Head Neck, 2013
    Head & Neck 03/2013; 35(3). DOI:10.1002/hed.21930 · 2.64 Impact Factor
  • Willis S Tsang · Michael C Tong · C Andrew van Hasselt ·

    Ear, nose, & throat journal 02/2013; 92(2):E27. · 1.00 Impact Factor
  • Victor James Abdullah · Dennis Lip Yen Lee · Stanley Ching Nam Ha · Charles Andrew van Hasselt ·
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    ABSTRACT: Objective This study examines subjects' level of consciousness with bispectral analysis in sedation endoscopy of the upper airway.Study DesignA prospective study.SettingUniversity hospital.Subjects and Methods Bispectral analysis levels recorded in natural sleep of 43 patients with obstructive sleep apnea during an overnight polysomnographic sleep study were directly compared with the levels recorded during midazolam sedation sleep endoscopy in the same subjects. The possible muscle relaxation effect of midazolam was examined via surface chin electrodes. Supine Müller maneuver findings in 50 patients with obstructive sleep apnea were also compared with soft tissue dynamics during midazolam sedation sleep endoscopy.ResultsIn our study of the 43 patients with bispectral analysis during natural sleep and midazolam sedation sleep endoscopy, a predominance of bispectral analysis values indicating N1 and N2 sleep was observed during the sedation study. Midazolam failed to achieve deeper levels of sleep with minimal N3 and no convincing rapid eye movement. As N1 and N2 are the stages during which maximal dynamic activities occur, and they make up an average of 70.5% of total sleep time, from 210 sleep studies at our laboratory, the present technique would be ideal as a surgical assessment tool. No muscle relaxation effect could be detected at our protocol dose of midazolam. The supine Müller maneuver findings were significantly different from those observed during sedation sleep.Conclusion These findings support the value of sleep endoscopy as an efficient and informative technique for the examination of upper airway dynamics relevant to focused surgical planning.
    Otolaryngology Head and Neck Surgery 10/2012; 148(2). DOI:10.1177/0194599812464865 · 2.02 Impact Factor
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    ABSTRACT: The substantial T lymphocyte infiltrate found in cases of nasopharyngeal carcinoma (NPC) has been implicated in the promotion of both tumor growth and immune escape. Conversely, because malignant NPC cells harbor the Epstein-Barr virus, this tumor is a candidate for virus-specific T cell-based therapies. Preventing the accumulation of tumor-promoting T cells or enhancing the recruitment of tumor-specific cytotoxic T cells offers therapeutic potential. However, the mechanisms involved in T cell recruitment to this tumor are poorly understood. Comparing memory T cell subsets that have naturally infiltrated NPC tissue with their counterparts from matched blood revealed enrichment of CD8(+), CD4(+), and regulatory T cells expressing the chemokine receptor CXCR6 in tumor tissue. CD8(+) and (nonregulatory) CD4(+) T cells also were more frequently CCR5(+) in tumor than in blood. Ex vivo studies demonstrated that both receptors were functional. CXCL16 and CCL4, unique chemokine ligands for CXCR6 and CCR5, respectively, were expressed by the malignant cells in tumor tissue from the majority of NPC cases, as was another CCR5 ligand, CCL5. The strongest expression of CXCL16 was found on tumor-infiltrating cells. CCL4 was detected on the tumor vasculature in a majority of cases. These findings suggest that CXCR6 and CCR5 play important roles in T cell recruitment and/or retention in NPC and have implications for the pathogenesis and treatment of this tumor.
    American Journal Of Pathology 03/2012; 180(3):1215-22. DOI:10.1016/j.ajpath.2011.11.032 · 4.59 Impact Factor
  • Siu Kwan Ng · Hok Yuen Yuen · Charles A van Hasselt · Anil Ahuja ·
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    ABSTRACT: Transcutaneous vocal cord injection is a popular treatment choice for patients suffering from unilateral vocal cord paralysis. Transcutaneous transcartilaginous (through the thyroid cartilage) approach abolishes any anatomical constraint to reach the vocal cord. However it is a largely blind procedure as the needle should stay submucosal. Herein we report our experience in employing ultrasound guidance to circumvent this problem. Retrospective review of a series of 8 patients who underwent combined ultrasound/endoscopy-assisted vocal cord injection for unilateral vocal cord paralysis. Vocal cord injections were successfully completed in all but one patient. There were no associate complications. The use of ultrasound in aiding transcutaneous transcartilaginous vocal cord injection is safe and feasible. • Vocal cord injection is effective in treating unilateral vocal cord paralysis • A number of transcutaneous approaches with the patient awake have been described • Transcutaneous transcartilaginous approach theoretically has minimal anatomical restraint to reach the vocal cord • Disadvantage of that approach is the difficulty to accurately position the needle • Our experience of using ultrasound to circumvent this problem is positive.
    European Radiology 12/2011; 22(5):1110-3. DOI:10.1007/s00330-011-2337-6 · 4.01 Impact Factor
  • Wendy M.Y Kwan · Victor J Abdullah · Kelvin Liu · C Andrew van Hasselt · Michael C F Tong ·
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    ABSTRACT: Objective : To determine the incidence of otitis media with effusion and the associated hearing loss, the rate of ventilation tube insertion, and complications of ventilation tube insertion in Chinese cleft palate patients. Design : Retrospective review in a tertiary care hospital in Hong Kong. Patients : A total of 104 consecutive patients with cleft lip and/or cleft palate who were born between January 1996 and January 2006. Results : The incidence of otitis media with effusion in Chinese cleft palate patients for the first 2 years after birth was 76.1%. Of these patients, 16.9% had otitis media with effusion associated with a moderate hearing loss (>40 decibels hearing level [dBHL]). Approximately half (53.2%) of our patients had ventilation tube insertion. Complications including retraction, tympanosclerosis, and perforation of the tympanic membrane were found in 15.7% of all ears with otitis media with effusion and ventilation tube insertion. Conclusions : The high incidence of otitis media with effusion in cleft palate infants found in this study is consistent with that reported in the Western literature. A small but significant proportion of otitis media with effusion was associated with moderate hearing loss that truly required surgical treatment. Cleft palate children are much more likely to develop otitis media with effusion than normal children, and they develop the condition at an earlier age. A protocol for the treatment of otitis media with effusion in cleft palate patients and further prospective studies are warranted.
    The Cleft Palate-Craniofacial Journal 11/2011; 48(6):684-9. DOI:10.1597/10-006 · 1.20 Impact Factor
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    Louisa K Y Ng · Kathy Y S Lee · Sung Nok Chiu · Peter K M Ku · C Andrew van Hasselt · Michael C F Tong ·
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    ABSTRACT: There is a paucity of knowledge on dysphagia in patients with nasopharyngeal carcinoma postradiotherapy (NPC post-RT). The purpose of this study was to establish silent aspiration occurrence, safe bolus consistency, and their relationship with swallowing physiology in patients with dysphagic NPC post-RT. Eighty-five patients with dysphagic NPC post-RT were assessed across 4 bolus consistencies. We compared penetration-aspiration scores against 4 swallowing physiology impairments. Silent aspiration occurred in 65.9% of patients with dysphagia, with 64.7% on thin fluids, 35.3% on thick fluids, 11.8% on pureed diet, and 5.9% on soft diet. Multivariate analysis of variance (MANOVA) indicated pharyngeal contraction and swallowing response had significant effect on thick fluids (p = .002), thin fluids (p = .017), and soft diet (p = .031). Silent aspiration of thin fluids is a common occurrence in dysphagic NPC post-RT, with least aspiration noted on soft diet. Considering the high incidence of silent aspiration, instrumental assessment in this cohort is crucial.
    Head & Neck 09/2011; 33(9):1335-9. DOI:10.1002/hed.21627 · 2.64 Impact Factor
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    ABSTRACT: Background The purpose of this study was to identify independent prognostic factors that influenced local relapse-free survival (LRFS) and overall survival (OS) of patients who underwent salvage surgery for residual or recurrent nasopharyngeal carcinoma (NPC).Methods Ninety-seven patients who had been treated with radiotherapy or chemoradiotherapy for NPC underwent a nasopharyngectomy for a residual or recurrent local tumor between November 1987 and June 2007. The subsequent minimum follow-up was 2 years. Univariate and multivariate analyses were performed to identify prognostic factors for LRFS and OS.ResultsThe 5-year LRFS and OS was 46.7% and 51.9%, respectively. On multivariate analysis for LRFS and OS, respectively, recurrent regional disease (hazard ratio [HR], 3.245; p = .008) and (HR, 4.990; p = .001), and positive surgical margins (HR, 5.963; p = .000), and (HR, 4.912; p = .000) were independent prognostic factors.Conclusion In patients undergoing surgical salvage nasopharyngectomy for residual or recurrent NPC, positive surgical margins have an independent negative influence on LRFS and OS. © 2010 Wiley Periodicals, Inc. Head Neck, 2011
    Head & Neck 08/2011; 33(8):1126 - 1131. DOI:10.1002/hed.21585 · 2.64 Impact Factor
  • A.-C. Vlantisp · W.-F. Bower · T. Chung · C.-A. van Hasselt ·

    Oral Oncology 07/2011; 47. DOI:10.1016/j.oraloncology.2011.06.123 · 3.61 Impact Factor
  • A.-C. Vlantis · H. Gao · E. Wong · E. Ng · P. Chiu · C.-A. van Hasselt ·

    Oral Oncology 07/2011; 47. DOI:10.1016/j.oraloncology.2011.06.140 · 3.61 Impact Factor
  • C L Sham · K F To · Paul K S Chan · Dennis L Y Lee · Michael C F Tong · C Andrew van Hasselt ·
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    ABSTRACT: The purpose of this study of human papillomavirus (HPV), Epstein-Barr virus (EBV), p21, and p53 in sinonasal inverted papilloma (IP) was to help elucidate its pathogenesis. Seventy-three IPs, 48 nasal polyps, and 85 hypertrophied turbinates were subjected to HPV polymerase chain reaction (PCR) study. Seventy-three IPs, 30 nasal polyps, and 32 hypertrophied turbinates were subjected to EBV in situ hybridization (ISH), p21, and p53 immunohistochemical (IHC) studies. HPV was positive in 3 of 73 IPs (4.1%). All specimens were EBV negative. In all, 99% of IPs showed strong and diffuse p21 nuclear reactivity. Most nasal polyps and hypertrophied turbinates showed weak to moderate immunoreactivity of the basal and parabasal cells. Only focal p53 immunoreactivity of the basal and parabasal cells was found in 19% of IPs and 40% of nasal polyps. HPV prevalence of our IP is low. EBV is not present in IP. High p21 and low p53 expression in IP suggests a non-p53-dependent regulation pathway.
    Head & Neck 05/2011; 34(4):520-33. DOI:10.1002/hed.21772 · 2.64 Impact Factor

Publication Stats

3k Citations
534.09 Total Impact Points


  • 1990-2014
    • Prince of Wales Hospital, Hong Kong
      Chiu-lung, Kowloon City, Hong Kong
    • The Chinese University of Hong Kong
      • • Department of Otorhinolaryngology, Head & Neck Surgery
      • • Department of Surgery
      Hong Kong, Hong Kong
  • 1994
    • University of Liverpool
      • Department of Clinical Sciences
      Liverpool, England, United Kingdom
  • 1993
    • University of Southampton
      Southampton, England, United Kingdom
  • 1992-1993
    • Caritas Hong Kong
      Chiu-lung, Kowloon City, Hong Kong