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Biomedical subjects

S W Yeo

Publications and source records attributed to S W Yeo.

15 recordsLinked to original sources
PubMed2001

Different distribution of HLA class II alleles according to response to corticosteroid therapy in sudden sensorineural hearing loss.

OBJECTIVE: To investigate the association of HLA class II alleles with the susceptibility to sudden sensorineural hearing loss and with the results of corticosteroid treatment in the Korean population. DESIGN: HLA-DRB1, -DQA1, -DQB1, and -DPB1 genotyping by the sequence-specific oligonucleotide probes method in 41 patients with sudden sensorineural hearing loss and in 206 healthy control subjects. Initial hearing levels at the onset of hearing loss and final hearing levels after treatment were evaluated for the association with HLA class II alleles. SETTING: Tertiary care referral center, ambulatory and hospitalized care. SUBJECTS: Forty-one patients (24 men and 17 women; mean age, 49.2 years) were compared with 206 controls. Patients were divided into 2 groups according to their response to corticosteroid therapy (good response vs nonresponse). RESULTS: The frequencies of HLA-DRB1, -DQA1, -DQB1, and -DPB1 alleles were not significantly different between patients and controls (P>.05). When an association between the results of corticosteroid treatment and the frequency of HLA alleles was evaluated, the frequencies of HLA-DRB1*14 (relative risk [RR] = 3.5, P<.02), -DQA1*03 (RR = 4.2, P<.02), and -DQA1*05 (RR = 3.1, P<.03) were significantly increased, but HLA-DQA1*01 (RR = 0.2, P<.004) and -DQB1*06 (RR = 0.2, P<.009) were decreased in the group nonresponsive to corticosteroid therapy, compared with the controls. The distribution of HLA-DQA1*01 (P<.04), -DQB1*06 (P<.02), and -DQA1*03 (P<.003) was significantly different between the responsive and the nonresponsive groups. HLA-DQA1 allelic combination analysis showed that the frequencies of DQA1*03 and *05 had a high RR value in patients with sudden sensorineural hearing loss (RR = 4.1, P<.003) and in patients in the nonresponsive group (RR = 8.9, P<.001), compared with the controls. CONCLUSION: The presence of HLA class II alleles may be a useful genetic marker in forecasting a prognosis in Korean patients with sudden sensorineural hearing loss.

Alleles↗
PubMed2001

Effects of antibiotics and steroid on middle ear mucosa in rats with experimental acute otitis media.

The prevention of mucosal changes induced by experimental pneumococcal otitis media by means of antibiotics has been demonstrated previously. However, the effect of combined antibiotic and steroid therapy on the middle ear mucosa in acute otitis media (AOM) has not been determined. The right middle ears of 27 rats were inoculated with a log-phase type 3 Streptococcus pneumoniae, with the left ears serving as controls. Penicillin G was administered to nine rats and penicillin G and dexamethasone in combination were administered to nine rats after bacterial challenge; the remaining nine rats were not treated. Three animals from each group were sacrificed on Days 4, 7 and 14 after challenge. Tympanic membranes and middle ear mucosa were examined using otomicroscopy and light microscopy. Structural changes were diminished in both the antibiotic-treated and antibiotic + steroid-treated groups, compared with those in the untreated infected controls. The antibiotic + steroid-treated group showed the most marked decrease in structural change, especially in the mucosal metaplasia to the secretory epithelium. The results suggest that combination therapy with antibiotics and steroid in AOM is the most effective at reducing the treatment period and preventing persistent mucosal changes, which may decrease the risk of development of secretory otitis media as a sequela of AOM.

Acute Disease↗
PubMed2001

Effect of tumor necrosis factor-alpha on experimental otitis media with effusion.

OBJECTIVES/HYPOTHESIS: Up to the present, many reports have demonstrated that local immune response is associated with maintenance and persistence of effusion in the middle ear cavity. Resulting retention of inflammatory cells and mediators in the middle ear results in ongoing effusion. The purpose of this study was to clarify the role of tumor necrosis factor in experimental otitis media with effusion, which was induced by transtympanic injection of tumor necrosis factor in the rats. STUDY DESIGN: Four groups were designed in two experiments. The purpose of experiment 1 was to confirm that transtympanic injection of TNF-alpha produces the middle ear effusion. In experiment 2, TNFsolRI was used to evaluate the possibility as an inhibitor in otitis media with effusion. METHODS: The histopathological changes were observed under light microscope, and the changes in microvascular permeability were examined using Evans blue vital dye technique. RESULTS: Middle ear effusion was developed in 70% of specimens, and histopathological changes, such as subepithelial edema and marked infiltration of neutrophils, were present in 100% at 24 hours after administration of tumor necrosis factor-alpha through transtympanic approach. Extravasation of Evans blue dye was found in all specimens injected by tumor necrosis factor-alpha, which was qualified using a fluorescence microscope and quantified using a spectrophotometer. These histopathological findings and changes in microvascular permeability were significantly reduced by tumor necrosis factor soluble receptor type I. CONCLUSIONS: Neutrophil infiltration, subepithelial edema, increased microvascular permeability, and resultant effusion were indirectly proved to be induced by tumor necrosis factor-alpha. We hope that this study may contribute to understanding the role of tumor necrosis factor-alpha in otitis media with effusion and clarifying the future role of tumor necrosis factor soluble receptor type I in preventing otitis media with effusion.

Animals↗
PubMed2001

Effect of inhibitor of tumor necrosis factor-alpha on experimental otitis media with effusion.

Tumor necrosis factor (TNF)-alpha is important in the pathogenesis of otitis media with effusion (OME). The purpose of this study was to determine the effect of TNF-alpha antagonist on the outcome of lipopolysaccharide (LPS)-induced OME in rats. Otitis media was induced by injecting Pseudomonas aeruginosa LPS transtympanically. Another (combination) group was pretreated with TNF-alpha antagonist, soluble TNF receptor type I (sTNF RI), before transtympanic injection of LPS. Saline and phosphate-buffered saline solutions were used as controls. Twelve hours after the transtympanic injection, otoscopic examination and aspiration of middle ear effusion (MEE) were done. The temporal bones in each group were examined histopathologically, and the vascular permeability of the middle ear mucosa was measured by the Evans blue vital dye technique. In the LPS and combination groups, MEE developed in 90% and 0% of ears, respectively. The combination group showed less inflammation, less mucosal thickening, and significantly decreased vascular permeability as compared to the LPS group. Transtympanic administration of sTNF RI appears to suppress the development of LPS-induced OME. This study suggests that TNF-alpha antagonist, along with antibiotics, may have an adjunctive role in the future treatment of MEE.

Animals↗
PubMed2001

Obstetric admissions to the intensive therapy unit of a tertiary care institution.

INTRODUCTION: Between 0.1% and 0.9% of women develop pregnancy complications which require admission to an intensive therapy unit. The aim of this study was to review all obstetric admissions to the intensive therapy unit at the KK Women's and Children's Hospital from 1998 to 1999 with respect to indications for admission, interventions employed and clinical outcome. METHOD: The medical records of all obstetric patients admitted to the intensive therapy unit during the 2-year period were analysed retrospectively. Subjects were included if they were admitted during pregnancy up to 42 days postpartum. RESULTS: There were 31,725 deliveries in our hospital during the study period of which there were 239 admissions to the intensive therapy unit. Of these, 42% were Malays, 41% Chinese, 12% Indians and 5% other races. 65% stayed 1 day, 24% 2 days, 7% 3 days and 4% more than 3 days. The patients' ages ranged from 18 to 44 years. The indications for admission were hypertension (50%), haemorrhage (24%), respiratory insufficiency (10%), neurological problems (11%) and sepsis (3%). Intervention-wise, 43% of patients required vasoactive infusions, 35% had arterial line placement, 22% central venous pressure monitoring, 21% ventilatory support and 2% pulmonary artery catheter placement. The maternal mortality and stillbirth rates were 1.3% and 3.7% of intensive therapy unit admissions, respectively. CONCLUSION: The admission rate to the intensive therapy unit in our institution was 0.73% of all deliveries during the 2-year study period. Hypertensive disease and haemorrhage were the predominant admitting diagnoses.

Adolescent↗
PubMed2000

Distribution of HLA-A, -B and -DRB1 alleles in patients with sudden sensorineural hearing loss.

This study was performed to investigate the association between human leukocyte antigen (HLA) and susceptibility to sudden sensorineural hearing loss in the Korean population. HLA-A and HLA-B typing using a standard microlymphocytotoxicity technique and HLA-DRB1 genotyping were performed in 35 patients with sudden sensorineural hearing loss and in 206 healthy controls. Prednisone (usual dose 60 mg/day) was administered for 6 days and tapered for an additional 4-6 days. Both initial hearing levels at the onset of deafness and final hearing levels after treatment were examined and evaluated for association with HLA alleles. The frequency of HLA-DRB1*14 was increased in patients with sudden sensorineural hearing loss compared with controls (relative risk [RR] = 2.7, p = 0.016). The frequencies of HLA-A2, -A31, -B52, -B61, -DRB1*04, -DRB1*11 and -DRB1*12 were slightly higher than in the controls, but did not reach statistical significance. When an association between the treatment results and HLA alleles was also evaluated, the frequency of HLA-DRB1*04 was found to be increased in the patients who did not respond to steroid treatment compared with both patients who responded well to steroid (50%, vs 16%, p = 0.034) and controls (RR = 3.0, p = 0.046). These results suggest that there is an association between HLA-DRB1*14 and disease susceptibility and that the presence of HLA-DRB1*04 may be an useful marker for predicting a poor prognosis in Korean patients with sudden sensorineural hearing loss.

Adult↗
PubMed1998

Streptococcal toxic shock-like syndrome in a post-myomectomy patient.

We report on a healthy 34-year-old woman who received an elective myomectomy for uterine fibroid, and postoperatively developed fatal streptococcal toxic shock-like syndrome. We discuss the series of events that led to this life-threatening disease and its pathophysiology, and suggest areas in which management might have been improved.

Journal Article↗
PubMed1997

Sedation for the conduct of lumbar epidural anaesthesia: a study using subanaesthetic dose of ketamine in combination with midazolam.

We gave sedation for the conduct of lumbar epidural analgesia using intravenous ketamine 0.3 mg.kg-1 with intravenous midazolam 2 mg. Forty adult Chinese females undergoing major gynaecological laparotomies had epidural catheter inserted before general anaesthesia, 20 of whom were given ketamine and midazolam (study group) and the other 20 acted as control. During the conduct of the epidural, the pain and anxiety scores in the study group were significantly less than the control group (P < 0.05). Patients were significantly more sedated in the study group (P < 0.05). All the patients in the study group were satisfied and would consent to future epidural versus 75% in the control group (significant at P < 0.05). Ninety per cent of patients in the study group had amnesia but none in the control group. Pain experienced during the epidural was the reason for refusal of future epidural. We did not observe any emergence phenomenon or cardiovascular stimulation. There was a statistically significant decrease in the pulse oximetry oxygen saturation (SpO2) in the study group but none required oxygen supplementation. We concluded that pain caused by the conduct of epidural did decrease the patient's acceptance rate to future epidural, and the combined use of intravenous ketamine 0.3 mg.kg-1 and midazolam 2 mg provided adequate sedation, analgesia, anxiolysis and amnesia to significantly increase the acceptance rate without any significant side effects.

Adult↗
PubMed1995

Antigen diffusion from the perilymphatic space of the cochlea.

The diffusion pattern of horseradish peroxidase (HRP) injected into the scala tympani of the cochlear basal turn of guinea pigs was studied to test whether antigen presented in this manner can gain access to the endolymphatic sac. By two hours, HRP reaction product was found throughout the cochlea, with the greatest amounts in the spiral ligament, spiral limbus, basilar membrane, and organ of Corti. In several cochleas, very weak labeling was seen in the stria vascularis. HRP reaction product was maximal in the basal turn. By two hours, HRP reaction product was also observed in the endolymphatic sac lumen, epithelial cells, subepithelial tissue, and perisaccular connective tissue. It was more common in the proximal portion. At this time, macrophages within the lumen already appeared to have phagocytosed the HRP. By 72 hours after injection, the inner ear was cleared of HRP. The results of this study support the hypothesis that antigen in the scala tympani gains access to the endolymphatic sac lumen, where it may be presented by macrophages to the systemic immune system. Antigen most likely does not gain access to the endolymphatic space in the cochlea, but it gets to the endolymphatic sac through the perilymph and the perisaccular tissue.

Animals↗
PubMed1994

Continuous spinal analgesia--initial experiences with differential sensory block and labour pain relief.

This report describes the use of microcatheters to provide continuous spinal analgesia for the relief of labour pain. Bupivacaine 0.025% was administered through a 28G spinal microcatheter resulting in a differential block which provided effective labour pain relief. Conduction by the smaller pain fibres from the uterus were blocked, while relatively sparing the larger A fibres. Motor power, sense of touch, and discrimination between blunt and sharp objects were therefore left relatively intact. Patients were thus spared the discomfort of motor paralysis and an intense sensory block. No patient had hypotension (blood pressure fall greater than 20%). However one patient suffered a severe post-dural puncture headache which required an epidural blood patch. Continuous intra-thecal spinal analgesia is a potential alternative to continuous epidural analgesia in the relief of labour pain.

Adult↗
PubMed1993

General anaesthesia vs sedation for minor gynaecological procedures--a comparative study.

Sedation using combined intravenous midazolam and fentanyl is a popular technique for minor gynaecological procedures. However, it is fraught with inconsistency in efficacy and has a greater tendency to perioperative oxygen desaturation. Fifty female ASA I patients scheduled for minor gynaecological procedures were given intravenous midazolam and fentanyl before surgery started. Intraoperative excessive movement that interfered with surgery and failure to maintain a patient airway were noted. Perioperative oxygen saturation was monitored with the pulse oximeter. In another group of 50 female ASA I patients, intravenous thiopentone was given and anaesthesia maintained with 67% nitrous oxide in 33% oxygen and 0.5% of isoflurane via a face mask. Results showed that 10% of the sedated patients had excessive movements that interfered with surgery, of which 6% needed a general anaesthetic. Twenty-two percent of the sedated patients needed maintenance of airway perioperatively. Perioperative oxygen desaturation was profound in incidence and degree in the sedated patients whereas no patient who received general anaesthesia desaturated. The perioperative incidence of desaturation in the sedated patients was 46%. Intraoperatively, 28% (p < 0.001) of the sedated patients had oxygen saturation in the range of 85 to 90% and 18% of them (p < 0.01) had oxygen saturation of less than 85%. Postoperatively 8% of the sedated patients had oxygen saturation of 85 to 90%. We conclude that general anaesthesia is more efficacious and safer than sedation in patients scheduled for minor gynaecological procedures. The same minimum standard of monitoring applied to general anaesthesia should be used for sedated patients.

Adolescent↗
PubMed1992

Difficult intubation: a prospective study.

Difficult intubation has been much discussed in the anaesthetic literature. The incidence of difficult intubation (11:560) was higher in obstetric patients (6:277) as compared to gynaecological patients (5:283) in our hospital. We tested the Mallampati's classification as a predictor of difficult intubation in 277 obstetric and 283 gynaecological patients. We recommend that Mallampati's classification can be used reliably (p less than 0.05) to predict difficult intubation in obstetric but not in gynaecological patients.

Adolescent↗
PubMedDate not supplied

Effects of platelet-derived growth factor-AA on the healing process of tympanic membrane perforation.

PURPOSE: Platelet-derived growth factor basic 30-kD disulfide-bonded dimer of A and B chains (PDGF-AA, PDGF AB, PDGF-BB) and a cytokine, promoting wound healing by its mitogenicity for fibroblast and by stimulating the production of fibronectin and hyaluronic acid. This article investigates the effect of PDGF on the healing process of tympanic membrane (TM) perforation. MATERIALS AND METHODS: The pars tensa of the posterior aspect of the TM of rats was excised and treated with 2 microg of PDGF-AA or placebo. The animals were killed at 3, 5, 7, 9, 11, 15, and 28 days after operation. The healing process of TM perforation was observed with a telescope and light microscope. The temporal bones were also immunohistochemically examined for PDGF-alpha receptor (PDGF-R(alpha)) and fibronectin. RESULTS: All PDGF-AA-treated TM were completely closed by 5 days after surgery, whereas some of the placebo-treated TM were not closed at 15 postoperative days. PDGF-AA induced the most prominent proliferation of the connective tissue by 9 postoperative days, after which the growth of the connective tissue decreased. By the 4th postoperative week, the PDGF-treated TM were slightly thicker than normal TM. An intense expression of fibronectin was detected in the connective tissue layer of the TM that were treated with PDGF-AA. PDGF-R(alpha) was expressed in the epithelial layer of both the PDGF-treated and control TM. CONCLUSION: These results show that PDGF-AA speeds up the healing process of TM defect, improves the rate of healing, and prevents atrophic changes in the healed TM by promoting the connective tissue growth. The use of PDGF-AA can be an effective alternative to surgery for managing TM perforations.

Animals↗
PubMedDate not supplied

The clinical evaluations of pathophysiology for congenital middle ear cholesteatoma.

PURPOSE: Congenital middle ear cholesteatoma (CMEC) is less common than the acquired variety. Many theories have been put forward to explain the pathophysiology of CMEC; however, none of them have been convincingly proven thus far. This clinical study was performed to analyze the case reviews; assess the characteristic features of CMEC, and evaluate the correlation between those features and the pathophysiology of CMEC. METHODS: The medical records of patients who underwent otologic procedures at the hospitals of the Catholic University, Seoul, Korea, from January 1993 to November 1998 have been reviewed. RESULTS: Of the 14 patients, 3 had cystic lesions isolated to the anterosuperior quadrant of the mesotympanum. The lesions were easy to remove and did not affect the patients' hearing. Eleven patients had more extensive disease with posterior mesotympanum involvement; the lesions were large, were often too extensive to indicate a formative site, and caused ossicular damage. CONCLUSION: CMEC manifests in 2 distinctive forms according to the formation site. This distinctive formation site suggests that the pathophysiology of posterior lesions may be different from that of anterior ones. For early diagnosis of CMEC, a screening program should be established for children to prevent more extensive disease.

Adolescent↗