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Biomedical subjects

M C Tong

Publications and source records attributed to M C Tong.

At least 37 records · Page 2Linked to original sources

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.

Child, Preschool↗

A double-blind comparative study of ofloxacin otic drops versus neomycin-polymyxin B-hydrocortisone otic drops in the medical treatment of chronic suppurative otitis media.

Active chronic suppurative otitis media poses a management problem when patients are being considered for surgical treatment. Topical antibiotics have demonstrated varying degrees of success in the management of discharging ears. The introduction of quinolones has revived interest in these topical agents. This double-blind study compares two antibiotics, namely ofloxacin and neomycin-polymyxin B, with similar in vitro sensitivities to Gram positive and Gram negative organisms. Fifty-two patients were selected randomly and the results show that ofloxacin eardrops have marginal benefits in symptomatic improvement (89 per cent versus 79 per cent, p = 0.27) and bacterial eradication (81 per cent versus 75 per cent, p = 0.81) in active chronic suppurative otitis media. Significantly fewer patients (seven per cent versus 29 per cent, p = 0.04) in the ofloxacin group had active disease at the end of the two-week treatment. We recommend the use of ofloxacin eardrops in managing active chronic suppurative otitis media since it has high clinical efficacy, contains no steroid component and has no demonstrated risk of ototoxicity.

Anti-Infective Agents↗

Adult croup.

Adult croup is a distinct disease entity that probably represents a heterogeneous clinical syndrome. Three cases of adult laryngotracheitis characterized by upper airway infection and progression to airway obstruction are illustrated. Close observation and prompt decisions regarding airway intervention are critical in effective management, and complete resolution is expected.

Adult↗

Ingested foreign bodies--a contemporary management approach.

A prospective study of all foreign body complaints presenting through our Accident and Emergency Department was conducted in a population where the condition is endemic. All patients were managed by otolaryngologists. Six hundred and eight patients were attended to yielding 179 foreign bodies. Making use of modern equipment and a practical approach, the requirement for examination under general anesthesia was 6.3 per cent. In this series there was a complication rate of 0.5 per cent.

Adolescent↗

The Hong Kong vascularized temporalis fascia flaps for optimal, mastoid cavity reconstruction.

The classical modified radical mastoidectomy offers the advantages of combining the mastoid cavity, the attic and the external canal into one cavity that remains open for inspection. However the ultimate goal to predictably produce well healed, dry and safe mastoid cavities despite receiving much attention has not been fulfilled. By employing basic surgical principles of wide access to facilitate meticulous removal of all cholesteatoma and then eliminating all raw surfaces of the bony cavity with pedicled vascularized deep temporalis fascia, the Hong Kong Flap technique achieves the highest percentage of dry, stable, disease free ears. This living fibrous tissue layer provides the optimal substrate for epithelial resurfacing while separating the mucosa and bone of the middle ear and mastoid from the surface epithelium. Excellent healing even under unfavourable circumstances is ensured by the rich blood supply to the pedicled temporalis fascia flap. Furthermore the technique obviates the need for second look procedures in more than two-thirds of cases as the cavity lining becomes transparent and simple observation is safe. The Hong Kong Flap was used to reconstruct 107 cavities between October 1988 and October 1992. 86 were performed for primary cholesteatoma removal and 21 for revision of discharging cavities. 103 (96%) healed soundly. There were 4 dry perforations. Minor complications occurred in 8 (7%) patients. 84 (78%) required n+o second exploratory operation. This is a straight forward procedure requiring no special technical skills. The concept is rational and provides the ideal management for cholesteatoma by achieving a dry, safe ear with one operation.

Cholesteatoma, Middle Ear↗

The 578-nm copper vapor laser in the treatment of cavernous hemangiomas in the oral cavity.

A variety of operative and nonoperative treatment methods have been proposed to deal with cavernous hemangiomas. In an otorhinolaryngological unit where experience has been gained from managing superficial vascular lesions in Chinese skin with the 578-nm copper vapor laser, three patients with symptomatic large mucosal hemangiomas in the oral cavity were treated. All lesions have shown significant shrinkage after a single treatment utilizing an energy level of 20 J/cm 2. No further treatment, surgical or laser, has been necessary after follow-up of at least 12 months. The unique biological and tissue interaction of the copper vapor laser light is believed to be responsible for this remarkable response.

Adult↗

The ectrodactyly-ectodermal dysplasia-clefting syndrome: a literature review and case report.

Ectrodactyly, atypical anhidrotic ectodermal dysplasia, and cleft lip and palate are the principal manifestations of ectrodactyly-ectodermal dysplasia-clefting syndrome. Intraorally, the common manifestations of the syndrome are hypodontia, enamel hypoplasia, and generalized microdontia. In addition, the patient may suffer from xerostomia and have a deeply fissured tongue. The oral mucosa appears, in some patients, to have an increased susceptibility to candidiasis. This case report describes a patient who exhibits many of the manifestations of the syndrome and explains ways in which many of the anomalies of the dentition can be esthetically and functionally corrected.

Abnormalities, Multiple↗

Tuberculous tracheobronchial strictures: clinicopathological features and management with the bronchoscopic carbon dioxide laser.

Tuberculous tracheobronchial stricture is a rare disease entity at the present time. We report our experiences with carbon dioxide laser treatment for four patients with tuberculous strictures that were resistant to conventional management. All patients were relatively young but were debilitated by the disease. The lesions differed from other forms of benign tracheal strictures as they tended to involve the trachea and right side of the lung and were often multiple. The reasons for this are related to the organism per se and the anatomical arrangement of the tracheobronchial airway. The pathophysiology of tuberculous strictures in the tracheobronchial airway and the technique of bronchoscopic laser resection are outlined.

Adolescent↗

Flexible nasopharyngoscopy for fish bone removal from the pharynx.

The use of flexible nasopharyngoscopy with biopsy forceps for the removal of fish bones found in the oropharynx and hypopharynx is described. One hundred and sixty-eight patients with ingested fish bones in the upper aero-digestive tract were studied over a 12-month period. Of these, 73 per cent were removed per-orally, or by indirect laryngoscopy. Fifteen per cent were removed using the fibreoptic nasopharyngoscope. Twelve per cent required a general anaesthetic and rigid oesophagoscopy for removal of fish bones at or below the level of the cricopharyngeus muscle. The technique has proven to be quick, well tolerated and low in morbidity. It is invaluable in patients in whom indirect laryngoscopy is unsatisfactory.

Endoscopes↗

DNA polymorphisms of the apolipoprotein B gene in Chinese coronary artery disease patients.

Five restriction fragment length polymorphisms (RFLP) of the apo B gene and their association with serum lipids and apolipoprotein levels have been studied in 139 Chinese patients with angiographically confirmed CAD (mean age 56.2 +/- 0.8 years) and 154 healthy Chinese subjects (mean 44.0 +/- 1.0 years) of both sexes. The patient group had significantly higher levels of serum total and LDL cholesterol; and apo B (P < 0.001) and lower HDL cholesterol and apo A-I (P < 0.001 and < 0.01, respectively). The frequencies of the rarer alleles of the ins/del, XbaI and EcoRI (but not the PvuII and MspI) polymorphisms were significantly lower in the Chinese compared to those reported in Caucasians. There was no significant difference in allelic frequencies of the signal peptide region (Ins/Del), XbaI, MspI and EcoRI sites of the apo B gene between the patient and control groups. The frequency of the rarer allele of the PvuII RFLP was significantly lower in the CAD patients (P < 0.05) compared to that in the control group (0.05 vs 0.10). None of the DNA polymorphisms was associated with a significant influence on serum lipid and apolipoprotein levels in the patients with coronary artery disease.

Alleles↗

Apolipoprotein(a) phenotypes, Lp(a) concentration and plasma lipid levels in relation to coronary heart disease in a Chinese population: evidence for the role of the apo(a) gene in coronary heart disease.

Elevated lipoprotein(a) (Lp[a]) concentrations are associated with premature coronary heart disease (CHD). In the general population, Lp(a) levels are largely determined by alleles at the hypervariable apolipoprotein(a) (apo[a]) gene locus, but other genetic and environmental factors also affect plasma Lp(a) levels. In addition, Lp(a) has been hypothesized to be an acute phase protein. It is therefore unclear whether the association of Lp(a) concentrations with CHD is primary in nature. We have analyzed apo(a) phenotypes, Lp(a) levels, total cholesterol, and HDL-cholesterol in patients with CHD, and in controls from the general population. Both samples were Chinese individuals residing in Singapore. Lp(a) concentrations were significantly higher in the patients than in the population (mean 20.7 +/- 23.9 mg/dl vs 8.9 +/- 12.9 mg/dl). Apo(a) isoforms associated with high Lp(a) levels (B, S1, S2) were significantly more frequent in the CHD patients than in the population sample (15.9% vs 8.5%, P less than 0.01). Higher Lp(a) concentrations in the patients were in part explained by this difference in apo(a) allele frequencies. Results from stepwise logistic regression analysis indicate that apo(a) type was a significant predictor of CHD, independent of total cholesterol and HDL cholesterol, but not independent of Lp(a) levels. The data demonstrate that alleles at the apo(a) locus determine the risk for CHD through their effects on Lp(a) levels, and firmly establish the role of Lp(a) as a primary genetic risk factor for CHD.

Adolescent↗

The hazards of button batteries in the nose.

Foreign bodies in the nose are commonly encountered in ORL practice. Miniature button battery impaction in the nose has rarely been reported. Seven such cases have been encountered, each suffering complications directly attributable to the button battery. The complications included septal burns in five patients leading to septal perforation in one child, one case of severe nasal bleeding and one case of necrosis of the lateral nasal wall. The site of maximal damage corresponded with the negative pole of the battery in every case. The possible explanation for this and mechanisms of cellular injury are proposed. This paper underlines the potential hazards of button batteries as foreign bodies in the nose and emphasizes the need for rapid removal and long-term follow-up of these patients.

Child, Preschool↗

Surgery for cardiac arrhythmias.

From March 1989 to March 1991, 17 patients underwent curative surgical ablation of cardiac arrhythmias at the Singapore General Hospital. In the supraventricular tachycardia group, 13 patients with the Wolff-Parkinson White syndrome (WPW) underwent surgical ablation of the accessory conduction pathway by the classical endocardial approach. Two patients who had atrioventricular nodal tachycardia (AVNRT) underwent surgical dissection around the atrioventricular node to divide one of the dual conduction pathway responsible for the tachycardia. In the ventricular tachycardia group, two patients underwent surgical ablation of the arrhythmic focus. There was no operative mortality in the supraventricular tachycardia group and there were no late deaths to date. All these patients underwent electrophysiological study just before discharge and most of them had a repeat test six months later. In the Wolff-Parkinson White group, surgical ablation was completely successful in 12 patients (92%), preexcitation recurred in one patient (8%) but non had recurrence of supraventricular tachycardia. The two patients who had atrioventricular nodal tachycardia were completely cured of recurrent supraventricular tachycardia and had normal atrioventricular conduction. In the ventricular tachycardia group, one was cured with no recurrence of tachycardia, is not on medication and is in New York Heart Association Class I status. The other died postoperatively of recurrent ventricular tachycardia and low cardiac output syndrome.

Adult↗

Surgical management of intrathoracic aortic aneurysm.

The pathology, clinical features, indications for surgery and the results of intrathoracic aneurysm are analysed in thirty-nine consecutive patients who underwent surgery at Singapore General Hospital from January 1986 through December 1990. There were twenty cases of non-dissecting aneurysm and nineteen cases of dissecting aneurysm or aortic dissection. The 30 day survival for the twenty patients with non-dissecting aneurysm was sixteen patients (80%). The best results were obtained in patients with aortic root aneurysms. The overall 30-day survival for the nineteen patients with aortic dissection was twelve patients (64%). The mortality was especially high in patients with acute aortic dissection (46%). Recent advances in the management of these aneurysms make early recognition and diagnosis mandatory to achieve the best results.

Adult↗