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Biomedical subjects

C Andrew van Hasselt

Publications and source records attributed to C Andrew van Hasselt.

At least 19 recordsLinked to original sources
PubMed2006

Parental suspicion of hearing loss in children with otitis media with effusion.

OBJECTIVE: This study aimed to evaluate the parental suspicion of hearing loss in children with otitis media with effusion (OME). As part of a population-based survey in a screening programme among 6- to 7-year-old Chinese children in Hong Kong, OME cases and controls were studied for the value of parental observations in the prediction of OME and hearing test results. SUBJECTS AND METHODS: Prior to the otoscopic and tympanometric examination of the children on school premises, a self-administered binary-choice question was sent to the parents asking whether there was any suspicion of hearing impairment. Positive screens and randomly selected negative screens were seen in a hospital clinic for the confirmation of case and control status 2 to 3 weeks after the school screening. Aural examination under microscopy, repeated tympanometry and stapedial reflex testing, and pure-tone audiometry (PTA) were conducted, and 117 cases and 159 controls were included in this study. RESULTS: The average PTA conductive threshold levels in the individual children with OME ranged from 3.8 dB to 40.0 dB with a group mean of 17.0 dB in the better-hearing ears. Parental suspicion of hearing deficit was significantly associated with OME (p<0.001) but not PTA findings (p=0.686). The sensitivity of parent-suspected hearing impairment to detect OME however was very low (19.7%). DISCUSSION: In other words, if we had relied on parental suspicion as the first screening, at least 80% of the OME cases would have been missed. We conclude that the parental suspicion of hearing loss is inadequate for the identification of mild hearing loss as caused by OME. Health education is recommended to improve parental awareness of the disease.

Auditory Threshold↗
PubMed2006

Rhinitis Symptom Utility Index (RSUI) in Chinese subjects: a multiattribute patient-preference approach.

BACKGROUND: The Rhinitis Symptom Utility Index (RSUI), originally developed in the United States, consists of a patient-preference weighting scheme and a 10-item questionnaire measuring the severity and frequency of rhinitis related symptoms over a 14-day period. This study aimed to determine whether the Chinese RSUI could adopt the US-based multi-attribute utility function (MAUF) in scoring rhinitis symptoms. METHODS: In a Hong Kong study, 116 Chinese adults with allergic rhinitis completed the RSUI questionnaire and 36-item Short-Form Health Survey (SF-36) after they had been seen by two otorhinolaryngologists for disease-severity ratings. Respondents then completed computer-administered direct preference measures, i.e., visual analogue scale (VAS) and standard gamble (SG) assessments. The VAS and SG data were used to estimate a MAUF for the Chinese-based RSUI. RESULTS: The derived MAUF was somewhat different than the one developed for the US RSUI. Test-retest reliability for the Chinese RSUI was satisfactory (ICC = 0.71, p<0.001). Scores differentiated among cases with mild, moderate, and severe symptoms (p<0.001); and between those who did and did not require medications to control symptoms (p = 0.031). Findings were significantly correlated with SF-36 domain scores (r = 0.19 to 0.37; p=0.041 to <0.001). When the US-based scoring function was applied to the Chinese subjects, the resulting mean RSUI score was significantly lower (p<0.001). Comparisons between directly measured VAS and SG scores between the US and Chinese samples, demonstrated significant differences (all p<0.05), with the US subjects consistently rating rhinitis symptoms as worse than Chinese subjects. CONCLUSIONS: The Chinese RSUI has good measurement properties that reflect patient preferences from the Chinese. Results suggest that there are differences in preference rating between US and Chinese subjects and that use of the US-based preference function for the RSUI would bias the measurement of rhinitis symptom outcomes in Chinese subjects.

Adult↗
PubMed2006

Laryngeal carcinoma: five-year survival and patterns of failure in 202 consecutive patients treated with primary or post-operative radiotherapy in Hong Kong.

OBJECTIVES: We aimed to conduct a retrospective analysis of patients treated with radiotherapy for laryngeal carcinoma at a single institution. METHODS: We analysed data from 202 consecutive patients treated with primary or post-operative radiotherapy for laryngeal carcinoma over a 10-year period. RESULTS: Sixty-nine patients had a T1, 65 a T2, 39 a T3 and 29 a T4 lesion. Forty-one patients were node-positive. The clinical stage was I in 67 patients, II in 53, III in 36 and IV in 46. Primary radiotherapy was given to 152 patients. The median follow up was 60 months. The five-year overall local control rate was 86 per cent, the ultimate local control rate was 93 per cent, the five-year regional control rate was 96 per cent, the five-year relapse-free survival rate was 82 per cent and the five-year overall survival rate was 69 per cent. CONCLUSIONS: Patients with laryngeal carcinoma treated with primary or post-operative radiotherapy had a five-year overall survival rate of 69 per cent.

Adult↗
PubMed2005

Risk factors for otitis media with effusion in Chinese schoolchildren: a nested case-control study and review of the literature.

OBJECTIVE: To identify the risk factors for otitis media with effusion (OME) in Chinese schoolchildren and analyse the results with reference to the review of the literature. METHODS: The study subjects were 6-7-year-old children drawn from a school-screening program for OME in Hong Kong. Both positive and negative screens attended a hospital clinic for further assessment with repeated otoscopic examination and tympanometry as well as pure tone audiometry within 3 weeks after the initial school-screening. During the visit, parents were interviewed to provide information with regard to the children's birth history, neonatal history, socio-economic background, otological history, past health, and medical history. These data formed the basis in the estimation of potential risk factors for OME. RESULTS: In the univariate analysis of 127 cases and 173 controls, significantly elevated odds ratios (OR) for OME were detected on the symptoms of atopy (OR = 2.21, p = 0.04), hearing loss (OR = 4.13, p = 0.001), nasal obstruction (OR = 1.94, p = 0.005), rhinorrhoea (OR = 1.61, p = 0.04), tonsillitis in the past 12 months (OR = 1.82, p = 0.02), and previous history of acute otitis media (OR = 6.89, p < 0.001). However, only three of them were found to be significant in the multivariate logistic regression model: nasal obstruction (OR = 1.67, 95% CI: 1.01-2.75); acute tonsillitis (OR = 1.68, 95% CI: 1.00-2.80), and previous acute otitis media episodes (OR = 5.75, 95% CI: 2.60-12.69). CONCLUSIONS: Risk factors identified in the Chinese schoolchildren for OME were comparable with previous western reports. A previous attack of acute otitis media was a major determinant for middle ear effusion.

Case-Control Studies↗
PubMed2005

Symptomatic and pathophysiological observations in a modified animal model of allergic rhinitis.

There are many animal models for studying allergic rhinitis. However, they either need a too long establishment period or fail to show significant late allergic responses. In the model described in this paper, guinea pigs were sensitized and challenged intranasally with ovalbumin according to a modified protocol. As controls, antihistamine-treatment and non-sensitized, non-treatment groups were studied in parallel. Early and late symptoms, passive cutaneous anaphylaxis (PCA) reaction, nitric oxide synthase (NOS) immunoreactivities, pathological changes in nasal mucosa and nasal lavage fluid (NLF), and histamine, TXB2 and p-LTs levels in NLF were evaluated. In contrast to the control groups, the model group exhibited typical symptoms, including late phase nasal blockage, and increased levels of IgG1 and IgE. Considerable eosinophil infiltration and eNOS immunoreactivities in nasal mucosa, and increased levels of histamine, TXB2 and p-LTs in NLF were also observed. This model was not only capable of showing satisfactory symptomatic and pathophysiological changes in allergic rhinitis but also showed good responses to antihistamine treatment. The model can be established in six weeks. For the first time, respiratory rate was employed as an index to reflect the nasal blockage of guinea pigs and it proved to be a reliable indicator.

Animals↗
PubMed2005

[Establishment of a modified intranasally ovalbumin induced animal model of allergic rhinitis].

OBJECTIVE: To observe the early and late symptomatic, pathological and immunological changes in an intranasal ovalbumin-induced animal model of allergic rhinitis in guinea pigs. METHODS: Guinea pigs were intranasally sensitized with ovalbumin absorbed on aluminum hydroxide and after 5 days' interval, they were challenged with 1% ovalbumin solution once every 3 days for total 11 times. Two control groups were studied in parallel, the positive treatment control group was treated with antihistamine and the negative control group was sham-sensitized and sham-challenged. Typical symptoms of allergic rhinitis, such as sneezing, nasal scratching, nasal blockage and rhinorrhea were evaluated. Passive cutaneous anaphylaxis reaction (PCA) was performed to measure the levels of IgG1 and IgE. Eosinophils infiltration and goblet cells in nasal mucosa were observed. In addition, the level of histamine and the number of total leukocytes and eosinophils in the nasal lavage fluid were also measured. RESULTS: In the model group, symptoms of sneezing, nasal scratching, nasal blockage and rhinorrhea were induced after ovalbumin challenge. The respiratory rate (RR), which reflected the resistance of upper airway, showed a biphasic change. In the PCA test, IgG1 and IgE levels increased after challenges. Eosinophil infiltration in nasal mucosa was more obvious in active groups in comparison to with the negative control group (P < 0.05 or < 0.01). The histamine, total leucocytes and eosinophils levels in nasal lavage fluid also showed higher in the model group (P < 0.05 or < 0.01). The antihistamine treated animals were also induced out above changes but modest compared with the model group (P < 0.05 or < 0.01). The negative control showed few of above changes with significant difference (P < 0.05 or < 0.01). CONCLUSIONS: Our results implied that the modified animal model of allergic rhinitis was capable of showing satisfactory symptomatic and pathophysiological changes in allergic rhinitis. It showed a biphasic nasal blockage with shorter establishment duration. The model also had good treatment reaction to antihistamine. The animal model we introduced may be useful in the study of allergic rhinitis.

Administration, Intranasal↗
PubMed2005

[Effects of budesonide, desloratadine and dexamethasone on interleukine-4 release and expression from human mast cell line].

OBJECTIVE: Since human mast cell is an important source of cytokines, it is of importance to understand the effects of anti-allergic drugs on cytokines modulation in mast cells. In the present study, we aimed at observing whether IL-4 could be released from human mast cell line (HMC-1) after the stimulation of PMA + A23187, and the effects of systemic glucocorticosteroid, dexamethasone, topical glucocorticosteroid, budesonide and H1 antagonist, desloratadine on IL-4 release and mRNA expression. METHODS: HMC-1 was stimulated with 25 ng/ml phorbol 12-myristate 13-acetate (PMA) and 2.5 x 10(-7) mol/L ionomycin (A23187) and cultured for 6 hours, 12 hours and 24 hours respectively in the presence or absence of 10(-6)-10(-10) mol/L concentrations of test drugs. Culture supernatants were collected and the levels of IL-4 were assayed by enzyme-linked immunosorbent assays (ELISA). The mRNA expression of IL-4 was measured by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: HMC-1 expressed IL-4 mRNA and the resulting protein production of IL-4 released after being stimulated with PMA plus A23187. Dexamethasone, budesonide and desloratadine had potent inhibitory effect on IL-4 release at any concentrations and time points, with significant deference (P < 0.05) compared to the control cells. The inhibitory effect did not show time-dependent and concentration-dependent manner. Desloratadine and budesonide showed neither up-regulatory nor down-regulatory effects on IL-4 mRNA expression at the test concentrations, however, desloratadine could down-regulate IL-4 mRNA expression. CONCLUSIONS: HMC-1 could express and produce IL4 after stimulation. Dexamethasone, budesonide and desloratadine all had inhibitory effects on IL-4 release from HMC-1. In addition, desloratadine could also inhibit the IL-4 mRNA expression.

Budesonide↗
PubMed2004

Quantitative analysis of cell-free Epstein-Barr virus DNA in plasma of patients with nonnasopharyngeal head and neck carcinomas.

PURPOSE: We investigated the detectability of EBV DNA in the plasma of patients with non-nasopharyngeal head and neck carcinomas (NNHNC). Previous studies have shown that EBV is present in the tumor tissue of some NNHNC. EXPERIMENTAL DESIGN: We recruited 101 patients with NNHNC and 48 healthy controls. Blood samples were taken from controls and patients before treatment. Tumor tissue samples were tested for the presence of EBV in the first 69 patients by in situ hybridization for small EBV-encoded RNA (EBER). Plasma EBV DNA was measured by real-time quantitative PCR in patients and controls. RESULTS: Squamous cell carcinoma (SCC) was the commonest histology (78 patients) followed by lymphoepithelial carcinoma (8 patients). EBER was detected in tumor cells in 7 of 69 patients tested. All of the EBER-positive tumors were lymphoepithelial carcinoma. Two controls (2 of 48; 4.2%) had detectable plasma EBV DNA. Plasma EBV DNA was detected in all of the patients with EBER-positive tumors, and in 23 of 94 (24.5%) patients with tumors of EBER-negative or unknown status. The proportion of plasma EBV DNA-positive cases in either group was significantly higher than that in the control group (P < 0.0027). Plasma EBV DNA concentrations in patients with EBER-positive tumors (median, 3827 copies/ml) were significantly higher than those in the controls (median, 0 copy/ml; P = 0.0001). Of patients with SCC, 21 (26.9%) had detectable plasma EBV DNA (median concentration, 34 copies/ml). Plasma EBV DNA concentrations in the whole group of patients with SCC (median, 0 copy/ml; interquartile range, 0-4 copies/ml) were also significantly higher than those in the controls (P = 0.001). CONCLUSIONS: Our data indicate that plasma EBV DNA reflects tumoral EBER status, and it may be of use as a tumor marker for EBER-positive NNHNC. The biological and clinical significance of low levels of circulating EBV DNA in the minority of patients with EBER-negative tumors remain to be elucidated.

Carcinoma, Squamous Cell↗
PubMed2004

Sensitivity and specificity of Epstein-Barr virus IGA titer in the diagnosis of nasopharyngeal carcinoma: a three-year institutional review.

BACKGROUND: IgA antibody titers to the Epstein-Barr virus (EBV) viral capsid antigen (EBV IgA-VCA) and to the EBV early antigen (EBV IgA-EA) are used to screen for nasopharyngeal carcinoma (NPC). This study evaluates the sensitivity and specificity of EBV IgA-VCA and EBV IgA-EA titers in screening patients for NPC and in those diagnosed with NPC at our institution. METHODS: The NPC status was determined for all patients who had their EBV IgA-VCA and EBV-IgA EA titers measured over a 3-year period, and the sensitivity and specificity were calculated. RESULTS: Five thousand one hundred ninety-six samples were analyzed. NPC was diagnosed in 215 patients. The sensitivity and specificity of a raised EBV IgA-VCA titer (> or =1:5) for diagnosing NPC were 89% and 80%, respectively, with a raised EbV IgA-EA titer (> or =1:5) having a sensitivity and specificity of 63% and 97%, respectively. CONCLUSIONS: Although the EBV IgA-VCA titer is sensitive for the diagnosis of NPC, it should not be used as the sole means of screening for NPC in a population in which NPC is endemic.

Antibodies, Viral↗
PubMed2004

The impact of severe acute respiratory syndrome on otorhinolaryngological services at the Prince of Wales Hospital in Hong Kong.

OBJECTIVES/HYPOTHESIS: The objective was to describe the impact of severe acute respiratory syndrome (SARS) on the services of the division of otorhinolaryngology-head and neck surgery at an academic tertiary referral hospital in Hong Kong. STUDY DESIGN: Descriptive. METHODS: Records of general and subspecialty outpatient attendance, ward admissions, ward bed occupancy, and elective and emergency surgery were obtained for the period since the SARS outbreak and for an equivalent period before the outbreak. The changes in these parameters were determined against the background of new SARS cases. RESULTS: Since the outbreak of SARS in March 2003, the weekly outpatient clinic attendance has declined by 59%, the number of operations performed by 79%, the average ward bed occupancy rate by 79% and the daily admission rate by 84%. A dramatic increase of 300% in the number of patients defaulting on their outpatient appointments was recorded. CONCLUSION: The substantial decrease in otorhinolaryngological services at an academic tertiary referral hospital in Hong Kong has been multifaceted. The decrease in attendance at the outpatient clinics reflects the increased number of patients defaulting on their appointments. Nonessential elective surgery was suspended soon after the outbreak, accounting for the decrease in the number of surgical procedures performed and partially for the decrease in ward bed occupancy and ward admissions. The temporary closure of the accident and emergency department contributed to the decrease in ward admissions and emergency surgical procedures. The reduced service offered by the hospital is having an impact on the quality of care available to patients with non-life-threatening otorhinolaryngological conditions.

Delivery of Health Care↗
PubMed2003

Autograft ossiculoplasty in cholesteatoma surgery: is it feasible?

OBJECTIVE: To investigate whether autologous ossicles can be safely used in ossicular reconstruction in cholesteatoma surgery after attempting cholesteatoma removal under the operating microscope. STUDY DESIGN: A prospective fine-section histological study of formalin-stored ossicles, harvested from cholesteatomatous ears, to evaluate for existence of residual cholesteatoma after surface disease clearance under the operating microscope. METHODS: One hundred four ossicles were harvested from 76 patients with cholesteatoma for the study. These malleus heads and includes were categorized into three groups: group 1, ossicles with retained shape and useful bulk, treated by microscopic stripping alone; group 2, ossicles with retained shape and useful bulk, treated by microscopic stripping and drilling; and group 3, badly eroded ossicles, treated by microscopic stripping alone. These treated ossicles were then subjected to 4 microm histopathological study. RESULTS: Residual disease was identified in 6 of the 104 ossicles. Residual disease was found only in badly eroded ossicles that are not suitable for reconstruction. All the usable ossicles were free of disease. CONCLUSIONS: Autologous ossicles that have retained body and bulk are safe to use for reconstruction after surface stripping under the operating microscope. Additional burring probably adds a further margin of safety.

Adolescent↗
PubMed2003

Endoscopic removal of sinonasal inverted papilloma including endoscopic medial maxillectomy.

OBJECTIVES/HYPOTHESIS: Surgical excision is regarded as the treatment of choice for sinonasal inverted papilloma. Resection can be performed endoscopically or through an external approach. Debate exists about which approach to use. The study presents different endoscopic techniques for various tumor locations and reviews the results. STUDY DESIGN: A prospective study and an integrated literature review. METHODS: Seventeen consecutive patients with inverted papilloma who underwent endoscopic surgical excision, including medial maxillectomies and modified Lothrop procedures, were analyzed. Preoperative symptoms, computed tomography and magnetic resonance imaging findings, operative findings, tumor stage, and outcomes were recorded. RESULTS: Thirteen male and four female patients presented with inverted papilloma between December 1993 and October 2001. Nasal obstruction was the most common presenting symptom (50%). Sixty-five percent of tumors were either stage II or stage III. Endoscopic resection was the primary treatment in 14 patients. Of the three patients who were secondarily treated endoscopically, one had recurrence and was subsequently found to have focus of squamous cell carcinoma. The overall recurrence rate was 6% and the incidence of malignancy was 6% (1 of 17). Recurrence rate for primary resections was zero (0 of 14). Five patients underwent endoscopic medial maxillectomies, and one patient with frontal sinus inverted papilloma was successfully treated with a modified endoscopic Lothrop procedure. CONCLUSIONS: Endoscopic sinus surgery is a viable treatment alternative for sinonasal inverted papilloma. Recurrence rates for primary treatment are comparable to external approaches. Close follow-up of patients is mandatory because recurrence may be associated with malignancy.

Adult↗
PubMed2002

Preoperative topical ofloxacin solution for tympanoplasty: a randomized, controlled study.

OBJECTIVE: To establish the efficacy of immediate preoperative ototopical ofloxacin eardrops in eradicating middle ear pathogens and improving operative outcome. STUDY DESIGN: Single-blind, randomized control study. SETTING: Tertiary referral center, ambulatory clinic, and hospital setting. PATIENTS: Consecutive patients with chronic suppurative otitis media for Type I tympanoplasty (myringoplasty). INTERVENTIONS: The patients were randomly assigned to 3 groups: Group A underwent 10-minute daily treatments with eardrops for 2 weeks before surgery, Group B underwent 3-minute daily treatments for 2 weeks before surgery, and Group C underwent no treatment. MAIN OUTCOME MEASURES: Preoperative and perioperative bacteriology and success of the surgery as defined by an intact tympanic membrane in the eighth week postsurgery. RESULTS: There were 101 patients entered in the study. The preoperative, perioperative, and postoperative observation of discharge and quantity of the discharge were compared, and no differences were found among the groups (Kruskal-Wallis test). The perioperative culture results were analyzed and 18/21 (86%) became culture negative in Group A, 23/27 (85%) became culture negative in Group B, and 3/21 (14%) became culture negative in the control group (Group C versus Group A or Group B, chi(2) tests p < 0.001). The success rates of surgery as defined by an intact tympanic membrane showed no difference: 28/33 (85%), 27/33 (82%), and 31/35 (89%) in Groups A, B, and C, respectively. The preoperative positive bacteriology rate in the surgical failures was 10/15 (67%), compared with 16/76 (21%) for the successful procedures (p < 0.001). CONCLUSION: Our study has shown that ofloxacin successfully eradicates most bacterial flora preoperatively. We cannot, however, confirm the benefits of its preoperative usage in improving the graft success rate.

Adult↗
PubMed2001

Lateralized carotid artery: an unusual cause of pulsatile tinnitus.

We describe the case of a patient who had a pulsatile tinnitus that was caused by a laterally displaced internal carotid artery. Her condition was treated with the use of a hearing did, which suppressed the tinnitus. We also review the literature on laterally displaced internal carotid arteries, and discuss their differentiation from a congenitally aberrant artery.

Carotid Artery, Internal↗
PubMed2000

Osteoradionecrosis of the temporal bone in nasopharyngeal carcinoma after radiotherapy: a case report.

Osteoradionecrosis of the temporal bone after external-beam radiotherapy for nasopharyngeal carcinoma is not uncommon following a long posttreatment interval. We describe the case of a man who had experienced this complication 13 years after he had undergone such radiotherapy. His condition resolved after removal of dead bone from the external auditory canal, followed by antibiotic therapy and periodic aural toileting.

Aged↗