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Biomedical subjects

T Y Tan

Publications and source records attributed to T Y Tan.

At least 19 recordsLinked to original sources
PubMed2006

First-line gemcitabine and carboplatin in advanced ovarian carcinoma: a phase II study.

OBJECTIVES: To evaluate tumour response rate and toxicities of gemcitabine and carboplatin in chemonaive subjects with advanced epithelial ovarian cancer. DESIGN: A phase II study. SETTING: Gynaecologic oncologic unit. POPULATION: Twenty chemonaive International Federation of Gynecology and Obstetrics (FIGO) stage IIIc and stage IV subjects with ovarian cancer. MAIN OUTCOME MEASURES: Tumour response, disease free and overall survival and toxicity. METHODS: Intravenous gemcitabine 1000 mg/m2 on day 1 and day 8 and carboplatin at area under centre (AUC) = 5 on day 1 were administered three weekly for six cycles. Subjects who received more than three cycles of chemotherapy were eligible for assessment of tumour response, while all the cycles of chemotherapy were assessed for toxicities. RESULTS: The mean age of the subjects was 57.3 years, and the median follow up was 38.7 months. Of the 18 eligible subjects analysed, 11 (61.1%) showed a complete clinical response, and the overall response rate was 83.3% (15/18). The median overall survival was 29.2 [95% (confidence interval) CI 22.8-35.6] months, and the median progression-free survival was 11.6 (95% CI 4.7-18.5) months. WHO grade 3 anaemia, neutropenia and thrombocytopenia was 7.6, 9.5 and 0%, respectively, on day 8, and 15.5, 12.2 and 15.5%, respectively, on day 15. Two subjects required a total of three hospital admissions for neutropenic sepsis, and two required five hospital admissions for platelet transfusion for severe thrombocytopenia. CONCLUSION: Chemonaive advanced ovarian cancer showed a high response rate to combined gemcitabine and carboplatin chemotherapy. The subjects developed moderate adverse reactions. Phase III study to evaluate the role of combined gemcitabine and carboplatin as first-line chemotherapy in ovarian cancer is warranted.

Anemia↗
PubMed2006

Emergence of community-associated methicillin-resistant Staphylococcus aureus in Singapore: a further six cases.

INTRODUCTION: The clinical features and molecular epidemiology of further cases of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection in Singapore are described. METHODS: Six cases of CA-MRSA infection that occurred between April and October 2004 are described. The bacterial isolates were tested for the presence of Panton-Valentine leukocidin (PVL) genes and typed via pulsedfield gel electrophoresis, staphylococcal chromosomal cassette mec (SCCmec) and multi-locus sequence typing. The results were compared with that of previously-reported local and international CA-MRSA isolates. RESULTS: There were four cases of cutaneous abscesses and one each of chronic osteomyelitis and endocarditis. CA-MRSA isolates from the last two cases tested negative for PVL genes. Three isolates were identical and related to the Oceanian clone, and one isolate to the predominant Taiwanese clone. The isolate causing osteomyelitis had a novel sequence type. CONCLUSION: CA-MRSA, though uncommon, is being isolated with increasing frequency in Singapore. A predominant clone (ST30- MRSA-IV) seems to be emerging locally.

Adult↗
PubMed2006

Enlarged cervical sympathetic ganglion: an unusual parapharyngeal space tumour.

Primary parapharyngeal space tumours are rare, but they pose not only diagnostic but also therapeutic challenges in head and neck surgery. Imaging studies, in particular magnetic resonance (MR) imaging, play a central role in the diagnosis of parapharyngeal space (PPS) tumours. Besides schwannomas, primary lesions arising from the sympathetic chain within the PPS are extremely rare. We describe a 49-year-old man in whom the cervical sympathetic ganglion became enlarged after radiotherapy for nasopharyngeal carcinoma, and appeared as a parapharyngeal mass. This phenomenon has not been reported in the literature. We also discuss the features of the enlarged cervical sympathetic ganglion on MR imaging.

Ganglia, Sympathetic↗
PubMed2006

The in-vitro activity of colistin in gram-negative bacteria.

INTRODUCTION: Colistin is a polypeptide antibiotic belonging to the polymyxins, and has been increasingly used for the treatment of multiresistant gram-negative infections. There is little current available data on the susceptibility of gram-negative bacilli to colistin, in part because susceptibility testing for colistin remains problematic, and also because the use of colistin is not widespread. This study tested clinical isolates of gram-negative bacilli for susceptibility to colistin using the reference susceptibility testing method of agar dilution. METHODS: 102 strains of gram-negative bacilli were collected over a one-year period. Antibiotic susceptibility profiles were derived from disc susceptibility testing, and organisms were identified by standard microbiological methods. Isolates were selected for inclusion in the study using susceptibility profiles and epidemiological data. Minimum inhibitory concentrations to colistin were obtained by performing agar dilution according to a standardised method. RESULTS: 30 percent of tested isolates were resistant to colistin. All Acinetobacter spp. and Escherichia coli were susceptible to colistin. Colistin resistance was detected predominantly in Stenotrophomonas maltophilia and Pseudomonas aeruginosa, but was also present in Enterobacter spp. and Klebsiella spp. CONCLUSION: Colistin resistance is uncommon in the Enterobacteriaceae, but present in a significant proportion of S. maltophilia and P. aeruginosa isolates. From the results of this study, we recommend that susceptibility testing be performed whenever the clinical use of the polymyxins is considered.

Anti-Bacterial Agents↗
PubMed2005

Point-of-care controls for nosocomial legionellosis combined with chlorine dioxide potable water decontamination: a two-year survey at a Welsh teaching hospital.

This study reports a two-year programme of attempted eradication of Legionella colonization in the potable water supply of a 1000-bed tertiary care teaching hospital in Wales. There was a simultaneous, point-of-care, sterile-water-only policy for all intensive care units (ICU) and bone marrow and renal transplant units in order to prevent acquisition of nosocomial Legionnaires' disease. The programme was initiated following a case of nosocomial pneumonia caused by Legionella pneumophila serogroup 1-Bellingham-like genotype A on the cardiac ICU. The case occurred 14 days after mitral and aortic valve replacement surgery. Clinical and epidemiological investigations implicated aspiration of hospital potable water as the mechanism of infection. Despite interventions with chlorine dioxide costing over 25000 UK pounds per annum, Legionella has remained persistently present in significant numbers (up to 20000 colony forming units/L) and with little reduction in the number of positive sites. Two further cases of nosocomial disease occurred over the following two-year period; in one case, aspiration of tap water was implicated again, and in the other case, instillation of contaminated water into the right main bronchus via a misplaced nasogastric tube was implicated. These cases arose because of inadvertent non-compliance with the sterile-water-only policy in high-risk locations. Enhanced clinical surveillance over the same two-year period detected no other cases of nosocomial disease. This study suggests that attempts at eradication of Legionella spp. from complex water systems may not be a cost-effective measure for prevention of nosocomial infections, and to the best of our knowledge is the first study from the UK to suggest that the introduction of a sterile-water-only policy for ICUs and other high-risk units may be a more cost-effective approach.

Adult↗
PubMed2005

Facial palsy from temporal bone lesions.

INTRODUCTION: Facial nerve palsy results in the loss of facial expression and is most commonly caused by a benign self-limiting inflammatory condition, known as Bell's palsy. However, there are other conditions which may result in injury of the seventh cranial nerve and the radiologist should be familiar with their imaging appearances. MATERIALS AND METHODS: The relevant anatomy of the facial nerve and pathology which may affect the intratemporal portion of the nerve is described. The role of imaging and choice of imaging modality is also reviewed. RESULTS: High-resolution computer tomography(HRCT) images of the temporal bone and magnetic resonance(MR) images of the facial nerve from 11 patients who presented with facial nerve palsy were used to illustrate how intratemporal facial nerve injury of other aetiologies can mimic Bell's palsy. The typical imaging appearance of Bell's palsy was also presented. CONCLUSIONS: Most patients with suspected Bell's palsy do not require radiologic imaging. However, when symptoms progress, persist or when there is multiple cranial nerve involvement, recurrent symptoms or subacute onset of facial nerve palsy, causes other than Bell's palsy should be considered.

Cranial Nerve Neoplasms↗
PubMed2004

Spontaneous cerebrospinal fluid otorrhoea via oval window: an obscure cause of recurrent meningitis.

Spontaneous cerebrospinal fluid (CSF) leak via the oval window is uncommon and can result in recurrent bacterial meningitis. Current understanding of spontaneous CSF otorrhoea is reviewed and a diagnostic algorithm is presented. A seven-year-old boy presented with bilateral congenital deafness and recurrent meningitis. High-resolution computed tomography (HRCT) of the temporal bone showed a labyrinthine deformity and communication between the internal auditory canal (IAC) and the cochlea. Subtotal petrosectomy with closure of the external acoustic meatus and eustachian tube was performed. Post-operatively, the child had no further episodes of meningitis. This rare and obscure cause of recurrent childhood meningitis requires a high index of suspicion and the use of diagnostic tools, especially HRCT.

Cerebrospinal Fluid Otorrhea↗
PubMed2004

Castleman's disease of the neck: a description of four cases on contrast-enhanced CT.

Castleman's disease of the neck is an uncommon benign lymphoproliferative disease that usually presents as homogeneously enhancing enlarged lymph nodes on contrast-enhanced CT scan. We described the appearance of four confirmed cases of Castleman's disease of the neck on contrast-enhanced CT scan. Three of these presented as a solitary enhancing lymph node and the fourth case presented with multiple bilateral enhancing lymph nodes. A central non-enhancing area was present in two of the three cases that presented as a solitary node. Pathological correlation of one of these cases showed that this was due to a central fibrotic scar. One of the enhancing nodes in the fourth case with multiple and bilateral lymphadenopathy also contained a central non-enhancing area. We would like to propose that if a central non-enhancing scar is observed in an enhancing lymph node in the neck on CT scan, Castleman's disease should be considered as a possible diagnosis.

Adolescent↗
PubMed2004

Temporal lobe encephalocoele presenting with seizures and hearing loss.

A case of a bilateral temporal lobe encephalocoele that presented as seizures and hearing loss for many years. Diagnosis was confirmed on CT and MR imaging, which showed deficiencies in the temporal bone. The patient subsequently underwent surgical repair and recovered from his presenting symptoms.

Encephalocele↗
PubMed2003

Advances in imaging in prenatal diagnosis and fetal therapy.

Technological advances in ultrasound have contributed to improvements in prenatal diagnosis. Transvaginal scanning and harmonic imaging have allowed better resolution and improved structural characterisation. Doppler techniques have further been improved, which allow accurate flow studies of vessels in the placenta and fetus. These have contributed much to the management of intrauterine growth restriction, fetal anaemia and twin-twin transfusion syndrome (TTTS). Three-dimensional sonography and magnetic resonance imaging ultrafast sequences are useful adjuncts to conventional 2-dimensional sonography, increasing the confidence and diagnostic accuracy of prenatal diagnosis. Fetal therapy has seen major advances in recent years as well, secondary to improvements in endoscopic instruments and surgical techniques. Selective Nd:YAG laser photocoagulation of communicating vessels and cord occlusion have been used to treat complications of monochorionic twins like TTTS and twin-reversed arterial perfusion sequence.

Female↗
PubMed2003

Imaging of congenital middle ear deafness.

INTRODUCTION: Conductive hearing loss, in the presence of a normal external ear, is usually due to an interference with the normal transmission of sound from the tympanic membrane across the ossicular chain to the oval window. If conductive hearing loss occurs in a young child, congenital middle ear pathology is the most likely cause. MATERIALS AND METHODS: High resolution computed tomography of the middle ear is the diagnostic modality of choice. Details of the imaging technique are outlined in this article. Eight cases of congenital middle ear deafness imaged in the radiological departments of Changi General Hospital and Tan Tock Seng Hospital in Singapore are illustrated. RESULTS: Congenital middle ear deafness may be classified into ossicular chain abnormalities, congenital ossicular fixation, congenital oval window atresia and congenital round window atresia. The imaging features for each category are described. CONCLUSION: With proper imaging technique and a systemic analysis of the images, the abnormalities that result in congenital middle ear deafness can usually be demonstrated on most occasions.

Deafness↗
PubMed2003

Idiopathic chronic fetomaternal haemorrhage resulting in hydrops--a case report.

INTRODUCTION: We report a case of idiopathic chronic fetomaternal haemorrhage (FMH) that developed in the late trimester. CLINICAL PRESENTATION: The patient presented with decreased fetal movement at 38 weeks gestation. Antenatal follow-up was uneventful with normal serial ultrasound performed at 22 and 35 weeks. Prior to delivery, the cardiotocography (CTG) was abnormal with decreased baseline variability and late deceleration. Emergency lower segment caesarean section was performed. Upon delivery, a hydropic neonate with a haemoglobin level of 3.9 g/dL was noted. The Kleihauer-Betke test was positive, confirming FMH. OUTCOME: The neonate later developed intraventricular haemorrhage (IVH) and spastic cerebral palsy on follow-up. DISCUSSION: It is possible for FMH to occur late at the third trimester leading to detrimental effect. The fact that FMH can occur without antecedent risk factors underscores the importance of further research, and a high index of suspicion.

Adult↗
PubMed2003

A case series of pre-viable severe twin-twin transfusion syndrome.

INTRODUCTION: We present a case series of pre-viable severe twin-twin transfusion syndrome (TTTS). CLINICAL PICTURE: In year 2000, there were 16,688 deliveries in KK Women's and Children's Hospital. Four cases that presented before 24 weeks gestation satisfied the sonographic criteria for severe TTTS: same-sex fetuses, absence of twin peak sign, thin intertwine membrane, polyhydramnios associated with large bladder in recipient twin, and oligohydramnios and small or absent bladder in donor twin. TREATMENT: Amnioreduction, septostomy and termination of pregnancy were offered. OUTCOME: In 1 case abortion was chosen. The follow-up was at least 18 months postnatal. There was 1 intrauterine death, 2 with severe neurological handicap and 3 with normal outcome. CONCLUSION: Pre-viable severe TTTS is associated with significant mortality and morbidity rates and should be diagnosed promptly and managed in a tertiary fetal medicine unit with multi-disciplinary input.

Adult↗
PubMed2003

Severe newborn encephalopathy unrelated to intrapartum hypoxic events: 3 case reports.

INTRODUCTION: Newborn encephalopathy is an important clinical problem associated with considerable morbidity and mortality and is pertinent in the assignment of blame in obstetrics litigation. CLINICAL PICTURE: We report 3 babies with severe neonatal encephalopathy. OUTCOME: In all 3 cases, intrapartum hypoxic insult was unlikely to be a significant contributing factor towards the development of neonatal encephalopathy. The aetiology was unclear in the first 2 cases and there was antecedent antenatal cause of feto-maternal haemorrhage in the last case. CONCLUSION: Prevention of neonatal encephalopathy was not possible in these 3 cases. We recommend that umbilical cord blood gases be clearly documented in such cases to reduce unnecessary obstetrics litigation of intrapartum asphyxia as the significant contributing factor to the poor neonatal outcome. Clinicians must have a high index of suspicion of antecedent causes and perform the necessary investigations to elucidate the aetiology of the neonatal encephalopathy.

Adult↗
PubMed2002

MRI of cochlear otosclerosis.

Cochlear otosclerosis is an uncommon cause of mixed and sensorineural hearing loss. This has a characteristic appearance on CT, producing a distinctive pericochlear hypodense double ring. However, its appearance on MRI is not as readily appreciated, producing a ring of intermediate signal in the pericochlear and perilabyrinthine regions on T(1) weighted images, demonstrating mild to moderate enhancement after gadolinium administration. Increased signal on T(2) weighted images may also be seen. Recognition of these MRI features is important as MRI may be the first modality of investigation, especially when patients present with symptoms indicative of sensorineural hearing loss. We review four patients who presented with sensoineural hearing loss, and who were imaged with MRI as the first line of investigation.

Cochlea↗
PubMed2002

Survey of public health laboratory protocols for reporting the antibiotic susceptibility of urinary isolates submitted from general practice.

This study set out to investigate the variation in laboratory reports of the antibiotic susceptibility of urinary isolates from specimens received from primary care. A questionnaire survey was conducted across Public Health laboratories in England and Wales, and 38 out of 47 questionnaires were returned. Seventy-nine percent of laboratories had community antibiotic guidelines for the management of urinary tract infections, and trimethoprim was the most common first-line antibiotic recommendation. Trimethoprim and nitrofurantoin were the most commonly tested antibiotics, and the oral cephalosporins were the most frequent second-line antibiotics tested. A wide variation in reporting was demonstrated, with 47% of laboratories reporting on the combination of trimethoprim, amoxycilline and an oral cephalosporin. In view of the increasing concern about antibiotic prescribing in the community, it may be useful to review local laboratory policies so that antibiotic susceptibility reporting is consistent with primary care antibiotic guidance.

Anti-Bacterial Agents↗
PubMed2001

Lack of relation between severity of stroke and severity of extracranial internal carotid artery lesions in Taiwanese first-ever ischemic stroke patients.

BACKGROUND AND PURPOSE: The authors attempt to determine whether hemodynamically significant extracranial internal carotid artery (ICA) lesions correlate with the severity of first-ever hemispheric ischemic stroke. METHODS: Carotid duplex was used to evaluate carotid arteries. The National Institutes of Health Stroke Scale was used to describe the severity of the stroke and was stratified as follows: 1-6 = mild, 7-15 = moderate, > 15 = severe. Duplex findings were categorized according to velocity criteria into < 50% stenosis if ICA peak systolic velocity (PSV) (cm/s) < 140 and > 50% stenosis if ICA PSV > 140 or ratio of ICA and common carotid artery in PSV > 2. No detectable flow at ICA was considered occlusion. Stroke subtype was classified according to TOAST criteria. RESULTS: Two hundred nineteen consecutive patients were enrolled, including 127 with mild, 65 with moderate, and 27 with severe stroke. The prevalence of ICA stenosis > 50% in each group was 3.6%, 1.4%, 0.9%, respectively. Two patients in the severe group had total ICA occlusion. The overall prevalence of significant ICA lesions was 6.8%. CONCLUSIONS: There is no positive correlation of stroke severity with the severity of duplex findings, which may be due to low prevalence of significant ICA lesions or other stroke mechanisms. Most of the patients had mild stroke, and the majority had ICA stenosis < 50%. Small-vessel occlusion tended to have mild severity of stroke. Intracranial artery lesions or other factors causing stroke in Taiwanese should be investigated. Given the low incidence of significant extracranial carotid disease in symptomatic Taiwanese stroke patients, routine screening of symptomatic Taiwanese for extracranial carotid artery disease does not provide enough information to determine stroke mechanism, and transcranial Doppler should be added to the screening tests.

Acute Disease↗