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Charles Andrew van Hasselt

Publications and source records attributed to Charles Andrew van Hasselt.

11 recordsLinked to original sources
PubMed2005

The combined olfactory test in a Chinese population.

OBJECTIVE: To establish an olfactory test in the Hong Kong Chinese population. STUDY DESIGN: Prospective analysis of the results of a combined olfactory test (COT) for patients with olfactory dysfunction and for normal subjects attending a secondary and tertiary ear, nose and throat centre. METHOD: Our COT was based on and modified from the Connecticut Chemosensory Research Centre test. It consisted of an odour identification test involving nine substances and a threshold test using a series of threefold dilutions of 1-butanol. From September 1998 to June 2002, 188 Hong Kong Chinese patients with olfactory dysfunction and subjects with normal olfaction were prospectively recruited. The subjects were categorized into normal, hyposmic and anosmic groups. The olfactory function of the main group of subjects (n = 153) was assessed with the COT by a blinded observer and also quantified with a visual analogue scale; the results were analysed to validate the discriminative ability of the COT. Another subgroup of subjects (n = 35) was tested with the COT twice with a two-week interval to evaluate test-retest reliability. RESULTS: There were 42 normal, 68 hyposmic and 43 anosmic subjects within the main group (total n = 153). The identification scores, threshold scores and combined olfactory scores were statistically significantly different between the anosmic, hyposmic and normal groups of subjects (p < 0.001). The combined olfactory score correlated with the visual analogue score and the correlation coefficient was 0.56 (p < 0.01). The mean time spent on each COT was 8.6 minutes (standard deviation = 3.4 minutes). The test-retest reliability of the COT was satisfactory, with a one-way model intraclass correlation coefficient of 0.87 (n = 35). CONCLUSION: The satisfactory discriminative ability and test-retest reliability of the COT have been demonstrated in this study. The COT is a feasible method for assessing sense of smell in the Hong Kong Chinese population.

Adolescent↗
PubMed2005

Array-based comparative genomic hybridization analysis identified cyclin D1 as a target oncogene at 11q13.3 in nasopharyngeal carcinoma.

Nasopharyngeal carcinoma is highly prevalent in Southern China and Southeast Asia. To unveil the molecular basis of this endemic disease, high-resolution comparative genomic hybridization arrays were used for systematic investigation of genomic abnormalities in 26 nasopharyngeal carcinoma samples. A comprehensive picture of genetic lesions associated with tumorigenesis of nasopharyngeal carcinoma was generated. Consistent chromosomal gains were frequently found on 1q, 3q, 8q, 11q, 12p, and 12q. High incidences of nonrandom losses were identified on chromosomes 3p, 9p, 11q, 14q, and 16q. In addition to previously characterized regions, we have identified several novel minimal regions of gains, including 3q27.3-28, 8q21-24, 11q13.1-13.3, and 12q13, which may harbor candidate nasopharyngeal carcinoma-associated oncogenes. In this study, gain of 11q13.1-13.3 was the most frequently detected chromosomal aberration and a 5.3-Mb amplicon was delineated at this region. Within this 11q13 amplicon, concordant amplification and overexpression of cyclin D1 (CCND1) oncogene was found in nasopharyngeal carcinoma cell lines, xenografts, and primary tumors. Knockdown of cyclin D1 by small interfering RNA in nasopharyngeal carcinoma cell lines led to significant decrease of cell proliferation. The findings suggest that cyclin D1 is a target oncogene at 11q13 in nasopharyngeal carcinoma and its activation plays a significant role in nasopharyngeal carcinoma tumorigenesis.

Animals↗
PubMed2005

In vivo real-time diagnosis of nasopharyngeal carcinoma in situ by contact rhinoscopy.

BACKGROUND: Nasopharyngeal dysplasia or nasopharyngeal carcinoma in situ (NPCIS) lesions have rarely been reported. Timely diagnosis of the preinvasive lesion may improve prognosis. Contact endoscopy has been documented to accurately differentiate normal cells of the nasopharynx from malignant cells and allows a real-time diagnosis of primary and recurrent nasopharyngeal carcinoma (NPC) in a clinical setting. However, the role of contact endoscopy in the diagnosis of NPCIS is unknown. METHODS: The superficial cells of the nasopharynx in a patient with NPCIS were examined in vivo under local anaesthesia by use of a contact rhinoscope. The contact endoscopic findings were correlated with the histologic findings of the biopsy. RESULTS: The atypical cells of the lesion were magnified and visualized under contact endoscopy. Histopathologic analysis of the biopsied tissue confirmed the presence of NPCIS staining positively for Epstein-Barr virus (EBV)-encoded RNA (EBER). No cell-free EBV DNA was detected in the sera of the patient. CONCLUSIONS: Contact endoscopy can accurately identify the atypical cells of a tiny preinvasive lesion in the nasopharynx in a clinical setting, which may not be evident in routine imaging examination.

Adult↗
PubMed2005

Spoken word recognition in children with cochlear implants: a five-year study on speakers of a tonal language.

OBJECTIVES: To study the effects of age at implantation and duration of implant use on the performance of spoken word recognition of pediatric cochlear implantees in a tonal language setting over a period of 5 years. DESIGN: Sixty-four children, given implants between the ages 1:01 and 14:09 (years:months), were divided into three age groups. They were tested on open-set word recognition ability at seven time intervals from before surgery to 5 years after surgery. Analyses of variance with repeated measurements were used to examine the effect of their age at implantation and the duration of implant use. RESULTS: Duration of implant experience was significant in spoken word recognition across the three age groups (p < 0.01). Children given implants below the age of 3 years caught up with the performance of the older children at 12 months after implantation. The difference in score reached statistical significance at 2 and at 3 years after surgery (p = 0.03, p = 0.00). CONCLUSIONS: The performance of Cantonese-speaking children was similar to that of English-speaking children in that better outcomes were associated with longer implant experience as well as when implantation occurred at a younger age. The children implanted before the age of 3 and who had an implant experience of more than 2 years outperformed the children who were given implants after the age of 6 and also sustained these higher scores throughout 5 years of postimplant testing.

Adolescent↗
PubMed2003

Modified tubeless anesthesia during endoscopy for assessment of head and neck cancers.

We evaluated a modified technique of administering anesthesia without a tube and with spontaneous respiration during video-assisted tele-laryngo-tracheo-broncho-endoscopy (TLTBE). The endoscopy was performed as an alternative to rigid ventilatory bronchoscopy during screening for synchronous tumors in the tracheobronchial tree in patients who had head and neck malignancies. Thirty consecutive patients who required diagnostic panendoscopy were selected for this study. During direct-suspension laryngoscopy, anesthesia was delivered by administering intravenous bolus injections of propofol at 0.5 to 2 mg/kg every 5 to 10 minutes. A good view of the larynx, trachea, and main bronchi was obtained with a 50-cm 0 degree telescope, which caused no obstruction of the airway. During laryngoscopy, arterial oxygen saturation levels, pulse rates, and blood pressures were stable in all patients. No apnea was associated with the use of propofol during any procedure, and we observed no intraoperative or postoperative complication in any patient. Video-assisted TLTBE is appropriate for patients with a grade 1 or 2 larynx, good cardiopulmonary function, and no significant airway obstruction. It is a safe and time-saving alternative to rigid ventilatory bronchoscopy for staging primary tumors and for screening for synchronous tumors in the respiratory tract.

Adult↗
PubMed2003

Esophageal perforation and neck abscess from ingested foreign bodies: treatment and outcomes.

Over a 6.5-year period, 5,848 patients who had ingested a foreign body were admitted to the ENT unit at the Prince of Wales Hospital in Hong Kong. Potentially serious complications developed in 12 patients (0.21%). Eight patients had an esophageal perforation; three had clinical evidence that their injury had been caused by the foreign body itself and five were deemed to have been injured iatrogenically during esophagoscopy. One of the latter group eventually developed an abscess. Four patients originally presented with an abscess. Three of these patients and the patient who later developed an abscess were treated with neck exploration and surgical drainage. One of the patients who initially presented with an abscess refused surgical treatment and was treated conservatively. Conservative treatment was also initiated for all patients who had a perforation. Patients on the conservative regimen were administered intravenous broad-spectrum antibiotics and were not permitted to take any food or liquids by mouth; they received their nutrition via either enteral feeding or total parenteral nutrition. Conservative treatment was successful in all seven patients with a perforation and no abscess and in the one patient with an abscess who refused surgery. Moreover, all four patients who underwent surgical treatment recovered. Our experience demonstrates that esophageal perforation related to an ingested foreign body can be safely treated by conservative means if the diagnosis is made before significant contamination occurs. Conversely, abscesses (cervical or mediastinal) related to an ingested foreign body should be explored and surgically drained.

Abscess↗
PubMed2002

Nasopharyngeal carcinoma in situ (NPCIS)--pathologic and clinical perspectives.

BACKGROUND: Dysplasia or carcinoma in situ lesions (NPCIS) of the nasopharynx have rarely been reported. The prevalence, biologic behavior, and the transformation period of the pure preinvasive lesions have not been fully explained. METHODS: All cases of NPCIS were retrospectively reviewed during the period between 1990 and 2000. The clinical features of all cases were studied. The biopsy samples were examined using light microscopy and in situ hybridization (ISH) for EBV-encoded RNA (EBER). The sera taken before and after the transformation were analyzed for anti-viral capsid antigen (VCA) EBV titers and circulating cell-free EBV DNA concentration. RESULTS: Three cases of NPCIS were identified. Two of the three cases subsequently developed into invasive NPC after initial presentation. The interval of transformation varied from 40 to 48 months. In all three cases, the specimens showed abnormal findings on light microscopy and positive staining for EBER. Elevated anti-VCA titers were present in two of the preinvasive lesions. No cell-free EBV DNA was detected in the sera of these patients during the preinvasive phase of the disease. CONCLUSIONS: Preinvasive NPC is a rare but distinct entity. Its transformation period can be as long as 4 to 5 years. Elevated anti-VCA titers, in the presence of abnormal cells on light microscopy, should alert the pathologist to perform ISH EBER studies to diagnose this rare condition.

Adult↗
PubMed2002

In vivo diagnosis of persistent and recurrent nasopharyngeal carcinoma by contact endoscopy.

OBJECTIVE: To evaluate the potential use of contact endoscopy for the diagnosis of persistent and recurrent nasopharyngeal carcinoma in postirradiated patients. STUDY DESIGN: Prospective study to examine 64 consecutive patients who have been irradiated for nasopharyngeal carcinoma in a clinic setting using contact rhinoscopes (Karl Storz, Tuttlingen, Germany [7215 AA, 0 degrees, and 7215 BA, 30 degrees; 23 cm long. 4 mm in diameter]). METHODS: The superficial cells of the posterior walls of the nasopharynx were stained with 1% methylene blue and examined with contact rhinoscopes with the patient under local anesthesia at high magnifications (x60 and x150). Biopsy of the areas under examination was performed. The contact endoscopic images were analyzed and correlated with the corresponding histological sections of the biopsy tissues. RESULTS: Contact endoscopy was performed in 64 patients (54 men; mean age, 42 y) with the use of local anesthesia. Four patterns of contact endoscopic findings were identified: squamous metaplasia (43 cases), postirradiation atypia (10), granulation tissue (6), and malignancy (5). In the last group, the nasopharynx appeared normal in two patients (40%). The findings of contact endoscopy correlated well with the histological findings (kappa reliability coefficient = 0.847; P <.001; diagnostic accuracy, 92.1%). For prediction of persistent and recurrent disease, the sensitivity and specificity of endoscopic findings were both 100%. CONCLUSION: Contact endoscopy is an accurate, reliable office-based procedure that allows for in vivo and in situ diagnosis of persistent and recurrent nasopharyngeal carcinoma in postirradiated patients.

Adult↗
PubMed2002

Tone perception ability of Cantonese-speaking children.

Studies have shown that while children acquire all Cantonese tones by age two, they are not able to label them reliably until approximately age 10. One possible explanation for the large age discrepancy may be the different methodologies used. This study aimed to (1) investigate a new research design for the collection of reliable tone perception data from young children; (2) compare lexical and nonlexical items for testing tone perception ability; and (3) identify the relative ease of perceiving the three basic tone contrasts in Cantonese, that is, high level/high rising (T1/T2), high level/low falling (T1/T4), and, high rising/low falling tones (T2/T4). The three tone pairs were presented to 31 children in the form of word and nonword stimuli. It was found that the research design could be used to assess the tone perception knowledge of children as young as 2;09. Significant differences were found between word and nonword stimuli and also in the identification of the T2/T4 contrast in comparison with the other two pairs. Children's overall tone perception abilities are discussed in detail with reference to the role of lexical knowledge and the potential for tone perception confusions arising from differences in fundamental frequencies for tone onset and offset.

Child↗