Biomedical subjects

Y Tung

Publications and source records attributed to Y Tung.

16 recordsLinked to original sources

PubMed2001

Structured data entry of clinical information for documentation and data collection.

Routine databases containing large amounts of clinical data represent a tremendous opportunity for the evaluation of health care practices and outcomes. However, data collected for administrative purposes has limitations in content, accuracy and completeness. Routine entry of clinical information directly into clinical information systems by care providers is one strategy to address this problem. We developed a structured data entry method, the Clinical Data Framework (CDF), which has been used to support the capture of clinical information by clinicians in the normal process of care delivery. A study of the CDF over a two month period showed that it improved the accuracy of completeness of data collection over a coding method which was based on selection of ICD-9-CM codes.

Data Collection↗

PubMed2000

Improved local control for early T-stage nasopharyngeal carcinoma--a tale of two hospitals.

PURPOSE: To study the efficacy of intracavitary brachytherapy (ICT) in early T-stage nasopharyngeal carcinoma (NPC). METHODS AND MATERIALS: All early T-stage (T1 and T2 nasal cavity tumour) NPC treated with a curative intent up to 1996 were analyzed (n=743), 163 from the Prince of Wales Hospital (PWH) and 25 from Tuen Mun Hospital (TMH) were given ICT after radical external radiotherapy (ERT; group A). They were compared with 555 patients treated with ERT alone (group B). The radiotherapy techniques were identical between the two hospitals. The ERT delivered the tumoricidal dose (uncorrected biological equivalent dose (BED)-10, > or = 75 Gy) to the primary tumour, and this did not differ in technique or dosage between the two groups. The ICT delivered a dose of 18-24 Gy in three fractions over 15 days to a point 1 cm perpendicular to the midpoint of the plane of the sources. RESULTS: The local failure was significantly less (crude rates, 6.9 vs. 13.0%; 5-year actuarial rates, 5.8 vs. 11.7%) and the disease-specific mortality was significantly lower (crude rates, 13.8 vs. 18.9%; 5-year actuarial rates, 12.2 vs. 15.2%) in group A compared with group B. ICT was the only significant independent prognostic factor predictive of fewer local failures. When ICT was excluded from the Cox regression model, the total physical dose or the total BED-10 uncorrected for tumour repopulation became significant in predicting the ultimate local failure rate. The two groups were comparable in the rate of the chronic radiation complications. A significant dose-tumour-control relationship existed, plotting the local failure as a function of the total physical dose or the total BED. CONCLUSIONS: Supplementing ERT, which delivered the tumoricidal dose (uncorrected BED-10, > or = 75 Gy), with ICT significantly enhanced ultimate local control in early T-stage (T1/T2 nasal infiltration) NPC. A significant dose-tumour-control relationship exists above the conventional tumoricidal dose level.

Adult↗

PubMed1998

Nasopharyngeal carcinoma---time lapse before diagnosis and treatment.

This is a descriptive study of 168 patients with nasopharyngeal carcinoma who were referred to public oncology departments for primary treatment between July and September 1996. The mean duration from the onset of the symptoms to histological diagnosis was 5.0 months; the duration ranged from 6.1 months (for patients presenting with nasal symptoms) to 1.8 months (for those with cranial nerve dysfunction). The mean period between the onset of symptoms and the seeking of medical advice was 2.9months. For 54% of the patients, there was a further delay of up to 2.4 months between the initial medical consultation and referral to the appropriate specialist. The majority (84%) of patients attended public institutions for histological confirmation. The mean total time taken from the onset of symptoms to the commencement of radiotherapy was 6.5 months (range, 1.3-74.0 months)---45% of the delay was attributed to the patient, 20% to initial consultations, 14% to diagnostic arrangement, and 21% to preparation for radiotherapy. Concerted efforts are needed to minimise further the time between the onset of symptoms and treatment. A substantial reduction in this delay can be achieved if both public and primary care doctors were made more aware of the significance of relevant symptoms.

Journal Article↗

PubMed1997

Relationship between nasopharyngeal colonization and the development of otitis media in children. Tonawanda/Williamsville Pediatrics.

Streptococcus pneumoniae, nontypeable Haemophilus influenzae, and Moraxella catarrhalis are the predominant bacteria associated with otitis media. A cohort of 306 infants was followed from birth through 12 months to determine frequency and duration of colonization and risk of acute otitis media (AOM) and otitis media with effusion (OME). M. catarrhalis was the most common bacterium isolated. Infants colonized at < or = 3 months of age were at increased risk of AOM and OME. Early colonization with M. catarrhalis revealed the greatest risk (relative risk [RR] = 1.24), especially for OME (RR = 1.57). There was a strong relationship between the frequency of colonization and OM (r = .37, P < .001,) for each pathogen. Although S. pneumoniae, nontypeable H. influenzae, and M. catarrhalis are part of the normal nasopharyngeal flora during infancy, an increased rate of colonization may identify a subpopulation of children that is at increased risk of OM.

Acute Disease↗

PubMed1993

Initial clinical (phase I) trial of TLC D-99 (doxorubicin encapsulated in liposomes).

A liposome-encapsulated form of doxorubicin (TLC D-99), which was shown in preclinical toxicology to be less toxic to the gastrointestinal tract and myocardium than free doxorubicin, was administered by constant infusion (1.00-1.80 h) to 38 patients in single doses of 20, 30, 45, 60, 75, and 90 mg/m2 every 3 weeks and daily for 3 days at doses of 20, 25, and 30 mg/m2/day. The dose-limiting toxicity was leucopenia: the maximum tolerated doses were one at 90 mg/m2 and three at 25 mg/m2/day. Nausea, vomiting, and stomatitis were minimal or absent at each dose; alopecia was minor. Fever and chills were noted at most of the doses, and malaise was seen in some patients, especially at the higher doses. No hepatic, renal, or other organ toxicities were observed. Clinical cardiac toxicity was not observed in any patient; however, the cumulative doxorubicin dose was greater than 400 mg/m2 in only one patient. There was large variation among patients in estimated pharmacokinetic parameters and profiles. Higher plasma levels and dose intensities were achieved with TLC D-99 than were predicted for free doxorubicin. Liposome-encapsulated doxorubicin was well tolerated and produced less nausea, vomiting, and stomatitis than would be expected with free doxorubicin administered at equally myelosuppressive doses.

Adult↗

PubMed1991

Measurement of urokinase-type plasminogen activator activity in sera of nasopharyngeal carcinoma patients by an immunocapture assay.

The urokinase-type plasminogen activator (uPA) activity in sera of patients suffering from nasopharyngeal carcinoma was examined by a uPA-specific immunocapture assay. The results revealed that the activity levels in the patient sera were significantly higher than that of normal healthy controls. The uPA activity also increased with the staging of the disease and the anti-EBV VCA IgA titre which is a diagnostic test for the disease, although the results were not statistically different. These findings showed that the levels of the enzyme were related to the spread of the disease. In addition, it was demonstrated that the sensitivity of the assay could be increased by using SDS. If the sera were treated with 0.2% sodium dodecyl sulphate (SDS) prior to the assay, higher levels of measureable PA activity were detected.

Antigens, Viral↗

PubMed1991

An evaluation of point and interval estimates in population pharmacokinetics using NONMEM analysis.

In a simulation study of the estimation of population pharmacokinetic parameters, including fixed and random effects, the estimates and confidence intervals produced by NONMEM were evaluated. Data were simulated according to a monoexponential model with a wide range of design and statistical parameters, under both steady state (SS) and non-SS conditions. Within the range of values for population parameters commonly encountered in research and clinical settings, NONMEM produced parameter estimates for CL, V, sigma CL, and sigma epsilon which exhibit relatively small biases. As the range of variability increases, these biases became larger and more variable. An important exception was bias in the estimate for sigma V which was large even when the underlying variability was small. NONMEM standard error estimates are appropriate as estimates of standard deviation when the underlying variability is small. Except in the case of CL, standard error estimates tend to deteriorate as underlying variability increases. An examination of confidence interval coverage indicates that caution should be exercised when the usual 95% confidence intervals are used for hypothesis testing. Finally, simulation-based corrections of point and interval estimates are possible but corrections must be performed on a case-by-case basis.

Computer Simulation↗

PubMed1991

Polymorphous low grade adenocarcinoma of the palate in a child.

We report a case of polymorphous low grade adenocarcinoma involving the palate of a 12-year-old girl, the first example of this tumour occurring in the paediatric age group. The tumour displayed infiltrative growth, neural invasion, variegated histological patterns, and minimal cytological atypia. The patient remained disease-free four years after wide local excision of the tumour. The distinction of polymorphous low grade adenocarcinoma from pleomorphic adenoma and adenoid cystic carcinoma is also discussed.

Adenocarcinoma↗

PubMed1989

Radiotherapy of brain metastases from carcinoma of the bronchus.

A retrospective study of 68 patients suffering from carcinoma of the bronchus with brain metastases is presented. They were treated in the Radiotherapy Department, Queen Elizabeth Hospital over a 5-year period (1982 to 1986). There were 42 male and 26 female patients. The age range was 30 to 78 years (median 58.5). All patients were treated with whole-brain photon irradiation using lateral opposing fields. The dosage could be divided into two groups: 30 Gy given in 10 to 15 daily fractions (30 patients), or 22.5 Gy given in five daily fractions (38 patients). There was no significant difference in the actuarial survival of the two groups (P = 0.37), the median survival being 7 and 6 weeks respectively. There was no difference in survival between the groups with different histological subtypes (P = 0.43). The 5-day short fractionation is the preferred treatment as it gives patients more time away from hospital. In 80.4% of patients there was progression of neurological symptoms before death. Increasing the dose of radiotherapy to the main bulk of tumour may improve the symptom-free survival or overall survival.

Adenocarcinoma↗

PubMed1987