Charles Andrew van Hasselt

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.

Endoscopic Terminal Dacryocystorhinostomy

Objective Traditional endoscopic dacryocystorhinostomy (DCR) involves creation of a lacrimal sac side hole that may close down in the presence of a partially patent lower lacrimal drainage system. Endoscopic terminal DCR is a modified DCR procedure designed to prevent this problem.

A prospective study of foreign-body ingestion in 311 children

OBJECTIVE: To determine the preferable management protocol of foreign body ingestion in pediatric patients. METHODS: All pediatric patients aged less than 12 years who presented with suspected foreign body ingestion in a hospital setting over a period of 3 years were prospectively studied. The usefulness of symptoms and various diagnostic procedures to identify the impacted foreign bodies were analyzed. RESULTS: Of 311 children aged 4 months to 12 years, 115 foreign bodies were encountered. The presentations in children aged younger than 5 years were markedly different from the older children, who behaved more like adults. All sharp foreign bodies (107 cases or 93%), mostly fish bones (90.4%), were found in the oropharynx under direct vision using either tongue depressor (57%), Macintosh laryngoscope (6%), indirect laryngeal mirror (2%) or transnasal flexible endoscopy (28%). Coins (eight cases or 7%) were the only foreign body impacted at or below the level of cricopharyngeus. A plain cervical X-ray has a low sensitivity (15.9%) and a high specificity (99.5%) in identifying the foreign bodies. CONCLUSIONS: As the majority of the foreign bodies were sharp bones and situated in the oropharynx, a management protocol involving examination with a tongue depressor, transnasal laryngoscope, selective lateral soft tissue neck X-ray, chest X-ray and watchful observation is usually adequate. Removal of these foreign bodies can be accomplished using a tongue depressor and Macintosh laryngoscope. Patients with a suspected coin ingestion have to be evaluated by X-ray, and a rigid pharyngo-oesophagoscopy should be the mainstay of treatment.

Nasal foreign bodies in children

This study investigates the pattern of pediatric nasal foreign body impaction and its management in a metropolitan area. Data was obtained from 147 children presenting to the Accident and Emergency Department over a 4-year period. The majority of foreign bodies were toys and household products. Complications which occurred, such as ingestion of the foreign body or epistaxis were usually related to attempts at removal. Fourteen cases of local complications resulted from button battery impaction. Most of these patients can successfully be managed without complication if correct procedures are adopted.

New Guidelines for Endoscopic Localization of the Anterior Ethmoidal Artery: A Cadaveric Study

Objectives To determine objective data to improve the methods of identification of the anterior ethmoidal artery during endoscopic dissection. Study Design Cadaveric dissection of adult human heads. Methods A 0°, 4-mm rigid endoscope was used to guide uncinectomy and frontoethmoidectomy. The location of the anterior ethmoidal artery was first determined visually and then confirmed by passing a needle through the anterior ethmoidal foramen from the orbit into the nose in all cases. The distances were endoscopically measured using a simple ruler between two nasal landmarks and the anterior ethmoidal artery. Results Fifty-six nasal fossae in 28 cadavers were dissected endoscopically. The median distance between the artery and the “axilla” formed by the anterior attachment of the middle turbinate to the lateral nasal wall was 20 mm (range, 17–25 mm), irrespective of the side. The measurement differed by less than 2 mm between the sides in the same individual. The median distance between the artery and the “axilla” formed by the medial and lateral crura of the lower lateral cartilage (superomedial edge of the nostril) was 62 mm (range, 55–75 mm) for both sides. The artery was found to be in direct alignment with the two “axillae” formed by the middle turbinate and the nostril edge. Conclusions The distance between the ethmoidal artery and the axilla of the middle turbinate showed the least intraindividual and interindividual variations. The tip of the endoscope (or the ruler) points directly at the anterior ethmoidal artery in the fovea ethmoidalis when its edge is aligned with the two nasal landmarks. These simple guidelines can aid the identification of the artery in endoscopic frontoethmoidectomy.Objectives To determine objective data to improve the methods of identification of the anterior ethmoidal artery during endoscopic dissection.

Management of ingested foreign bodies: a retrospective review of 5240 patients

This review was carried out to assess the effectiveness of our protocol designed for the management of ingested foreign bodies. It was a retrospective review of 5240 patients with ingested foreign bodies admitted over a five-year period to the Ear Nose and Throat Unit. These patients were managed according to a standardized protocol which was adopted and modified from our previous study. Under his management protocol, the mean hospital stay was 1.6 days. Flexible oesophagoscopy under local anaesthesia, and rigid oesophagoscopy under general anaesthesia, were performed in 1.5 per cent and 7.7 per cent of cases respectively. Major complications including oesophageal perforation and deep neck abscesses occurred in 0.19 per cent of patients. There was no mortality. This management protocol for ingested foreign bodies was both safe and cost-effective when compared to similar studies reported in the literature.

Congenital laryngeal cysts: current approach to management

Congenital laryngeal cysts are a rare cause of neonatal upper airway obstruction which may lead to serious morbidity and mortality if diagnosis and treatment are delayed. We reviewed our experience with nine patients over a six-year period. The annual incidence of this condition was 1.82 per 100,000 live births. The diagnosis can be confirmed safely by flexible laryngoscopy before definitive surgery is contemplated. Contrary to other studies, we found that endoscopic removal of cysts can achieve an effective cure without recurrence. Endoscopic deroofing is as effective as endoscopic excision but is technically simpler and thus is recommended as the treatment of choice.

Excision of the preauricular sinus: A comparison of two surgical techniques

Objectives To compare the long‐term recurrence rate of the standard technique (simple sinectomy) and the supra‐auricular approach (wide local excision) for the surgical management of preauricular sinuses.

Endoscopic resection of inverted papilloma of the nose and paranasal sinuses

The results of a retrospective study of 22 patients with inverted papillomas resected by the endoscopic approach are presented with a follow-up of 33 to 96 months. Twenty-one patients had unilateral disease and one patient had bilateral involvement. None of the patients had orbital or cranial extension. One patient had synchronous carcinoma in situ. Eight patients had undergone previous surgical procedures. Following endoscopic surgery, six patients had residual disease requiring further revisions. Three of these six patients eventually required excision via limited external approaches. No patient required lateral rhinotomy or mid-facial degloving procedures. No complication occurred in any of the patients. The advantages of endoscopic surgery include precise determination of tumour extent, preservation of normal mucosa and bony structures and avoidance of external scars. Close endoscopic follow-up is mandatory to ensure early recognition and treatment of recurrent disease. Although the endoscopic approach is gaining popularity for the treatment of inverted papilloma, indiscriminate application may result in a high recurrence rate. The endoscopic approach should be performed by experienced surgeons and restricted to carefully selected patients with nasal, ethmoidal and limited maxillary disease. More extensive disease should be managed by radical external approaches or by combining endoscopic with limited external approaches.

Tone discrimination in Cantonese-speaking children using a cochlear implant

Most tone perception tests for Cantonese-speaking cochlear implant users have been based on tone identification tasks which require significant cognitive development to be successfully completed. Results from such tests suggest that cochlear implant child users are performing at about chance level and may not be receiving much information about pitch using the implant. This paper reports on the ability of cochlear implant child users to discriminate pitch variations in Cantonese by using an experimental procedure based on play audiometry. As part of the study, the usefulness of higher rates of electrode stimulation for aiding tone discrimination is also examined. Cochlear implant users are shown to derive sufficient information about pitch to discriminate most tone contrasts relatively successfully, with performance being most variable for contrasts involving tones clustered in the lower register of the speakers fundamental frequency range. Contrary to hypothesis, higher electrode stimulation rates are not found to offer significant benefits for aiding pitch discrimination.