The role of microRNA in cisplatin resistance or sensitivity

INTRODUCTION

Cisplatin is a chemotherapy drug that has been used to treat a number of cancers for decades, and is still one of the most commonly used anti-cancer agents. However, some patients do not respond to cisplatin while other patients who were originally sensitive to cisplatin eventually develop chemoresistance, leading to treatment failure or/and tumor recurrence.

AREAS COVERED

Different mechanisms contribute to cisplatin resistance or sensitivity, involving multiple pathways or/and processes such as DNA repair, DNA damage response, drug transport, and apoptosis. Among the various mechanisms, it appears that microRNAs play an important role in determining the resistance or sensitivity. In this article, we analyzed and summarized recent findings in this area, with the aim that these data can aid further research and understanding, leading to the eventual reduction of cisplatin resistance.

EXPERT COMMENTARY

microRNAs can positively or negatively regulate cisplatin resistance by acting on molecules or/and pathways related to apoptosis, autophagy, hypoxia, cancer stem cells, NF-κB, and Notch1. It appears that the modulation of relevant microRNAs can effectively re-sensitize cancer cells to cisplatin regimen in certain types of cancers including breast, colorectal, gastric, liver, lung, ovarian, prostate, testicular, and thyroid cancers.

Acquired posterior choanal stenosis and atresia: management of this unusual complication after radiotherapy for nasopharyngeal carcinoma

PURPOSE

To report on acquired posterior choanal stenosis and atresia after radiotherapy for nasopharyngeal carcinoma.

MATERIALS AND METHODS

Four patients with acquired bilateral choanal atresia and 2 with severe unilateral choanal stenosis in the posterior choanae were identified after treatment of nasopharyngeal carcinoma with radiotherapy. The mean age was 42 years (range, 29 to 48 years). Two patients had stage II, and 4 had stage III disease, according to Ho's classification. They all received a 66 Gy dose of external irradiation delivered to the nasopharynx, and a mean dose of 62.6 Gy to the neck. Five patients had an additional 20 Gy delivered to the parapharyngeal region, and 1 patient had intracavitatory brachytherapy of 18 Gy delivered to the nasopharynx. The mean onset of symptoms was 10.5 months (range, 2 to 40 months) postirradiation. All patients were treated by transnasal endoscopic resection. Merocel epsitaxis packing (Medtronic Xomed, Jacksonville, FL) was used to stent the nasal airway for 2 weeks postoperatively.

RESULTS

The mean follow-up was 16.2 months (range, 14 to 18 months) after surgery. Four patients (67%) were symptom-free. Two patients (33%) had unilateral restenosis in the postnasal space that required revision surgery and further nasal stenting for 2 weeks, and both were subsequently free from further restenosis. No adverse postoperative complication occurred.

CONCLUSION

Acquired posterior choanal stenosis and atresia is an unusual long-term complication after radiotherapy that can be successfully treated with transnasal endoscopic resection. A 2-week Merocel nasal stent is recommended to prevent restenosis in the posterior choanae.

Middle ear effusions after radiotherapy: correlation with pre-radiotherapy nasopharyngeal tumor patterns

OBJECTIVE

The purpose of this study was to assess whether pretreatment tumor patterns of nasopharyngeal carcinoma (NPC) can predict the status of the middle ear after radiation treatment.

MATERIALS AND METHODS

Pretreatment and follow-up magnetic resonance imaging (MRI) was performed in 32 patients (64 ears) who had radiation therapy for NPC. For the purpose of analysis, the ears were placed into their pre-radiation therapy tumor pattern groups and the presence of middle ear effusion (MEE) with regard to eustachian tube (ET) invasion or displacement was identified.

RESULTS

MEEs were present in 31 (48.4%) ears after radiation therapy. All of the MEEs that resolved were in the preradiation therapy groups where tumor invasion of the eustachian tube was present irrespective of the amount of ET displacement. There was, however, no significant difference for resolved MEEs between ears with ET invasion or displacement (p = 0.32 and p = 0.71, respectively, Fisher's exact test). The MEEs occurred with significantly greater frequency in ears with minor ET displacement than in those with major ET displacement (p = 0.013, Fisher's exact test) as well as in previously normal ears compared with other groups (p = 0.008, Mann-Whitney U test).

CONCLUSION

A pre-radiation therapy NPC tumor pattern was not found that clearly predicted the outcome of MEE after radiation treatment. The findings, however, suggest that approximately one third of MEEs in patients with invasion of ET or paratubal structures, irrespective of the amount of ET displacement, resolve after therapy. The MEEs that were present in ears with ET displacement and no invasion did not resolve despite reversal of the displacement after treatment, which suggests that ET position plays a less important role than invasion in the resolution of MEE. It is, however, difficult to be certain, because ears with invasion were invariably associated with ET displacement, and the contribution of radiation therapy to the development of MEE further complicates the issue.

Giant benign sinonasal squamous papilloma: report of a case

We treated a patient with a giant squamous papilloma in the nasal cavity and maxillary sinus that extended through a bony defect into the oral cavity. The mass was excised with a combined endoscopic, Caldwell-Luc, and transoral approach. Lesions of this type are rare, but when they do occur, the rate of recurrence is high. Therefore, long-term followup, including endoscopic examination, is important.

Screening for otitis media with effusion to measure its prevalence in Chinese children in Hong Kong

In an attempt to gain a better understanding of the prevalence of otitis media with effusion (OME) in the Hong Kong community, and to compare the characteristics of the disease here with OME as it is described in the Western literature, we screened more than 6,000 6- and 7-year-old children with both clinical and audiologic examinations. The initial positive screening rate was 5.3%. Upon further evaluation, we determined that the overall prevalence of persistent OME was 2.2%. We found that the disease pattern and natural history of persistent OME in Hong Kong children are similar to those reported in the Western literature.

Efficacy of ondansetron for prevention of postoperative nausea and vomiting after outpatient ear surgery under local anesthesia

OBJECTIVE

To assess the efficacy and safety of intravenous ondansetron (4 mg) for the prevention of nausea and vomiting after middle ear surgery under local anesthesia.

SETTING

The study was conducted by Division of Otorhinolaryngology in Prince of Wales Hospital, which is a tertiary referral center and teaching hospital for The Chinese University of Hong Kong.

STUDY DESIGN

A double-blind randomized controlled trial.

PATIENTS

Fifty-eight Chinese patients undergoing tympanoplasty under local anesthesia from July 1995 to June 1997 were recruited. The mean age of patients was 42.8 years (range 18-71 years).

INTERVENTION

Patients were randomly allocated to receive a single dose of intravenous ondansetron (4 mg) (n = 29) or placebo (n = 29) immediately before surgery.

MAIN OUTCOME MEASURES

Patients were assessed for severity and frequency of postoperative nausea and vomiting at the 1st, 2nd, 4th, 8th, and 24th hours after middle ear surgery.

RESULTS

Female patients showed a higher prevalence of postoperative nausea and vomiting. Twenty-eight percent of the patients experienced postoperative nausea, of whom 14% also experienced vomiting. Although the ondansetron group demonstrated a lower prevalence of postoperative nausea and vomiting (PONV) (24% nausea and 10% vomiting) than the placebo group (31% nausea and 17% vomiting), significant reduction in postoperative vomiting only occurred in the first postoperative hour (p = 0.038). No complications or adverse side effects were found to be associated with the use of ondansetron.

CONCLUSIONS

Single-dose ondansetron (4 mg) given intravenously preoperatively significantly reduces postoperative vomiting in patients after tympanoplasty under local anesthesia and causes no adverse effects.

Case report of a mass that mimicked an antrochoanal polyp

We describe the case of a patient who was originally diagnosed with an antrochoanal polyp. During avulsion of the mass by endoscopic polypectomy, it was discovered that the stalk of the polyp actually arose from the mucosa of the right superior turbinate rather than from the mucosa of the maxillary antrum. A diagnosis of choanal polyp was made.

Nasal manifestation of extranodal Rosai-Dorfman disease--diagnosis and management

Two cases of Rosai-Dorfman disease with polypoid nasal infiltration mimicking nasal tuberculosis and malignant lymphoma are reported. This rare benign disease was first described by Rosai and Dorfman in 1969 and is characterized by histiocytic proliferation. It is seldom considered in the differential diagnosis of granulomatous diseases due to its rarity and histological similarity to other diseases. Extranodal manifestations of this disease are uncommon. Although no specific treatment can guarantee a sustained remission of this disease, surgery for loco-regional lesions can result in long-term symptomatic control and restoration of function. Both patients underwent endoscopic resection of the nasal polypoid lesions and have subsequently been free of recurrence. Loco-regional infiltration of the nasal cavity by Rosai-Dorfman disease is effectively managed by endoscopic resection.

Magnetic resonance imaging and audiologic assessment of middle ear effusions in patients with nasopharyngeal carcinoma before radiation therapy

OBJECTIVE

The aim of this study was to assess the performance of clinical methods, viz. otoscopy, pure-tone audiometry, and tympanometry in diagnosing middle ear effusions (MEEs) using magnetic resonance imaging as a reference standard.

STUDY DESIGN

A retrospective study of 46 patients with newly diagnosed nasopharyngeal carcinoma was performed comparing clinical evaluation and audiometry results with magnetic resonance imaging findings obtained before radiation therapy.

RESULTS

Twenty-two (25%) of the temporal bones imaged had both MEE and mastoid effusions, 24 (27%) had only middle ear fluid, and 29 (33%) had mastoid fluid alone. The sensitivity for tympanometry, audiometry, and otoscopy in detecting fluid in the middle ear was 96%, 92%, and 80%, respectively. Although tympanometry was most sensitive in diagnosing MEE, there was no statistically significant difference when comparing the overall accuracy of pure-tone audiometry air-bone gap and tympanometry (p = 0.7, chi-square test). Flat curve tympanograms (type B) only achieved a sensitivity of 45% but were of high specificity (92%). Forty-nine percent with negative pressure tympanograms (mean air pressures > -100 daPa) had no MEE.

CONCLUSIONS

Using magnetic resonance imaging as a reference standard, tympanometry is the most sensitive audiologic test in detecting the presence of MEE. The overall accuracy of tympanometry, pure-tone audiometry air-bone gap, and otologic examination was, however, not significantly different.

Polyotia--a rare external ear anomaly

A rare case of polyotia in a 7-year old boy associated with first arch syndrome is reported. The accessory auricle formed a well defined helix and conchal bowl located anterior to a normal auricle and an atretic external auditory meatus. Surgical resection and reconstruction resulted in a good cosmetic outcome.

Prevalence of otitis media with effusion in multicultural schools in Hong Kong

The prevalence of otitis media with effusion (OME) in Asia has only been studied in a limited fashion. This preliminary study forms part of a larger study aiming to establish the prevalence of OME in Hong Kong. One hundred and seventy-seven children (from multicultural schools) between the ages of five and 6.03 years were screened for OME otoscopy and tympanometry. Nine positive screens (5.1 per cent) were obtained for OME. Within this mixed ethnic group, Chinese children had a significantly lower point prevalence (1.3 per cent) than Caucasian children (9.5 per cent) (p < 0.05). Although the point prevalence from this mixed ethnic group of children was significantly higher (p < 0.05) than that of local Chinese school children (1.95 per cent) by the same group of investigators, the point prevalence in the ethnic Chinese children was comparable. The reason for the lower prevalence of OME in the Chinese population needs further research.

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.

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.

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.

Preliminary results of photodynamic therapy for recurrent nasopharyngeal carcinoma

Photodynamic therapy (PDT) is a promising new modality in the treatment of cancer. In Hong Kong where nasopharyngeal carcinoma (NPC) is endemic, radiotherapy has been the primary treatment of choice. For recurrent disease after radiotherapy, there is no effective treatment. This latter report summarizes our initial experience in using PDT for these patients. Twelve patients (three females and nine males) with ages ranging from 33 to 65 years were treated with an infusion of hematoporphyrin derivative (5 mg/kg) 48-72 h before exposure to 200 J/cm2 light (wavelength, 630 nm) delivered from a gold vapor laser. All 12 patients showed a dramatic response as judged by computed tomography or magnetic resonance imaging at 6 months post-PDT. Of the eight patients in whom cure was aimed for, three remained disease-free at 9-12 months after a single treatment. Three of the remaining four patients achieved useful palliation. Skin hypersensitivity occurred in two patients and was the only significant complication encountered. This experience indicates that PDT can be an encouraging palliative or definitive management for recurrent superficial NPC.

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.

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.

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.

Tubeless anesthetic technique for optimal carbon dioxide laser surgery of the larynx

PURPOSE

To evaluate the operative conditions and safety of a tubeless technique of anesthesia for carbon dioxide laser surgery of the larynx.

MATERIALS AND METHODS

This prospective study evaluated 78 consecutive procedures in 72 adult patients undergoing carbon dioxide laser microlaryngeal surgery. Anesthesia was maintained by an intravenous infusion of Propofol (ICI Pharmaceuticals, Cheshire, UK) while the patient breathed spontaneously without endotracheal intubation.

RESULTS

The operative conditions were optimal in 76 of the 78 procedures providing a clear uninterrupted view of the larynx with no combustible material in the surgical field.

CONCLUSIONS

This series shows the technique described to be safe without risk of combustion and provides an unobstructed view to the larynx.

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.

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.

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.

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.

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.

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.

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.

Coronary artery bypass in patients with impaired left ventricular function

Myocardial revascularisation in patients with severe left ventricular dysfunction has been shown to improve survival. This report analyses the efficacy of myocardial revascularisation in this subset of patients with coronary artery disease manifesting severe left ventricular dysfunction on the basis of left ventricular ejection fraction (LVEF). Twenty-two consecutive patients with coronary artery disease complicated by severe left ventricular dysfunction underwent aorta-coronary bypass electively at Singapore General Hospital for the 3 year period ending February 1989. Twenty-one patients have angina +/- congestive heart failure refractory to medical therapy. One patient had congestive heart failure and objective evidence of ischaemia confirmed by preoperative thallium stress test. Nineteen (82.6%) patients had triple-vessel coronary artery disease. The mean LVEF for the series was 25% with the range from 10-13%. The duration of follow up was 6 months to 3 years (mean 24 months) with follow up survival data on 100% of patients. The hospital mortality was 9% (2/22) and there were 3 late deaths. Of the 17 survivors available for direct assessment, 12 reported improvement in their symptoms and 3 are completely asymptomatic. These preliminary results indicate that myocardial revascularisation can be performed in patients with severe LV dysfunction at an acceptable risk and that operation results in improvement in survival expectation and symptoms compared with medical therapy.

Anti-arrhythmic surgery for atrioventricular junctional and atrioventricular re-entrant tachycardia--a report of six cases

Since 15th March 1989, six patients with recurrent supraventricular tachycardia (SVT) had antiarrhythmic surgery performed. There were 4 males and 2 females, ages ranged from 23 to 62 years (mean 41 years). Two of these patients with the Wolff Parkinson White (WPW) syndrome also had syncope. Five of these patients had atrioventricular re-entrant tachycardia (AVRT) involving the bypass tracts. Two patients with the WPW syndrome had persistent antegrade conduction, two had intermittent conduction and the last patient had no antegrade conduction via the bypass tract. The bypass tracts were localised at the left free wall in all the five patients. Only one patient had atrioventricular junctional re-entrant tachycardia (AVJRT) of the slow-fast type. The indications for surgery for these patients include failed medical therapy, "dangerous" arrhythmias and patient's preference. All the patients had surgery performed using the endocardial dissection technique on the cardioplegic heart. There were no perioperative mortality and morbidity. All the patients were discharged within 2 weeks. To date, none of the patients had clinical recurrence of SVT and only one patient remained in atrial fibrillation and is on digoxin. In conclusion, antiarrhythmic surgery should be considered for patients with "symptomatic" palpitations as it is curative with a resumption to normal life.

Left main coronary artery obstruction: surgical experience with 93 patients

Among patients with ischemic heart disease, those with left main stem coronary artery stenosis has attracted most attention due to their ominous prognosis. During the period from August 1982 to February 1989, 93 patients underwent left main coronary artery revascularisation procedures at Singapore General Hospital. All the patients had greater than 75% obstruction of the left main coronary artery. Significant triple vessel disease occurred in 35 patients (37.6%), double vessel disease in 32 patients (34.4%), single vessel disease in 21 patients (22.6%) and left main coronary as an isolated lesion in 5 patients (5.4%). The overall hospital mortality rate is 6.5% and perioperative infarction rate is 8.6%. Since mid-1985, the hospital mortality rate has been reduced to 3.7% and the perioperative infarction rate to 4.9%. Average grafts per patient was 3.5. Intra-aortic balloon pump was used in 5 patients. Follow up period was from 5 months to 84 months with a mean of 36 months with the majority of patients in either New York Heart Association Class I or II and still alive.

Ventricular septal rupture in acute myocardial infarction

This is a review of 31 patients with ventricular septal rupture occurring in myocardial infarction which have been managed at the Singapore General Hospital. Ventricular septal rupture occurs more frequently in the elderly, in females and those presenting with the first myocardial infarction. Very few have a prior history of stable angina pectoris before the myocardial infarction. Sudden deterioration as manifested by an increase in heart rate, fall in blood pressure and signs of right heart failure in a patient with acute myocardial infarction (AMI) especially if accompanied by a systolic murmur should encourage a search for a mechanical cause, especially a ventricular septal rupture. 2D echocardiography or Swan-Ganz catheterisation are 100% diagnostic and can be easily and rapidly done at the bedside. Medical management includes vasodilator therapy and inotropic support. Intra-aortic balloon counterpulsation is especially useful and was instituted in 6 patients. Early surgical repair of the ventricular septal defect is important if overall prognosis of these patients is to be improved. Our operative survival of 42.9% is comparable to others, considering that without surgery all have died. Survival appears to be related to the site of the myocardial infarction (very poor prognosis in inferior myocardial infarction), operative treatment (no survivors if treated conservatively) and the mode of presentation (poor prognosis in patients who develop a ventricular septal rupture while in hospital).

Surgical revascularisation for diffuse CAD--an experience in 116 cases

There were 94 male and 22 female, age ranges 32 to 71 years with a mean age of 54 years. All of them had angina pectoris and strong positive stress test inspite of maximum medical treatment. All had severe triple vessel disease including (12 (10%) had critical left main stem lesion, 68 (52%) were diabetic and hypertensive, 51 (44%) had myocardial infarct with 16 (14%) of them showing global hypokinesia of ejection fraction 30%. The average grafts per patient was 3.8 Seventy-nine patients (68%) and RCA endarterectomy; 19 (16%) had right and left coronary endarterectomy and 18 (15%) had left coronary artery endarterectomy. One-hundred and three (86%) were reconstructed with saphenous vein graft. 13 (12%) with IMA grafts. There was no operative mortality. Two hospital deaths and two late deaths occurred in those patients who had very poor left ventricular function. The perioperative infarct rate was 2.7%. All patients were followed-up regularly at 2 weeks, 3 months, 6 months, postoperatively. The mean follow-up was 18 months ranging 10 to 43 months. Clinically over 95% are free from angina pectoris with improved effort tolerance. We conclude that endarterectomy with patch angioplasty is an effective and safe procedure in treating Diffuse Coronary Artery Disease which cannot be treated by bypass alone. The incidence of Diffuse Coronary Artery Disease is likely to increase in the future as the percutaneous balloon angioplasty is becoming more widely practised and Re-do CABG patient would come to surgery at a more advanced state of the disease.

The influence of verapamil on the gastric effects of stress in rats

The influence of verapamil on stress- or bethanechol-induced gastric effects was investigated in rats. Intraperitoneally injected verapamil (1, 2 or 4 mg/kg), given 30 min beforehand, dose-dependently prevented gastric glandular ulceration, mast cell degranulation and the increased stomach wall contractions evoked by restraint at 4 degrees C for 1 h. Gastric acid secretion, as well as ulceration in both the forestomach and glandular segment, produced by subcutaneously-injected bethanechol (3.2 mg/kg) were also inhibited. It is concluded that decreased amine release from the mast cells, stomach wall relaxation and reduced gastric acid were responsible for the ulcer-antagonising effects of the calcium-entry blocker. The possible antiulcer actions of verapamil are discussed in the light of present knowledge regarding calcium involvement in the various mechanisms thought to contribute to the pathophysiology of stress ulceration in rat stomachs.

Anorectal anomalies: a review of 49 cases

A series of forty-nine cases of anorectal anomalies treated in the Department of Surgery, Singapore General Hospital, is reviewed. The incidence of ano-rectal malformation in the Singapore population is estimated to be one in 11,500 live births. There is a significant male preponderence with a ratio of 7 to 3. Supralevator lesions accounted for 55% of the cases and of this group, 31% had associated congenital anomalies. In contrast only 11% of the low anomalies had other congenital defects. All patients were treated surgically either by anoplasty for the low lesions or staged rectoplasty for the intermediate and high lesions. The results of surgery for the low anomalies were uniformly good. In the group with high anomalies 7 cases had a good results, 21 had a fair result with occasional soiling only, and 2 cases had a poor result with frank incontinence.