Biomedical subjects

Tina Chou

Publications and source records attributed to Tina Chou.

7 recordsLinked to original sources

PubMed2006

Radiology curriculum topics for medical students: students' perspectives.

RATIONALE AND OBJECTIVE: We sought to establish medical students' perspectives of a set of curriculum topics for radiology teaching. MATERIALS AND METHODS: A multicenter study was conducted in New Zealand. A modified Delphi method was adopted. Students enrolled in two New Zealand Universities received a questionnaire. Each learning topic was graded on a scale of 1 (very strongly disagree) to 6 (very strongly agree). Students could also put forward and grade suggestions that were not on the questionnaire. RESULTS: Of 200 questionnaires, 107 were returned. Fifty male and 57 female students participated, with an average age of 23.7 years. The five highest ranking curriculum topics in order of importance were developing a system for viewing chest radiographs (5.77, SD 0.7), developing a system for viewing abdominal radiographs (5.66, SD 0.8), developing a system for viewing bone and joint radiographs (5.56, SD 0.8), distinguishing normal structures from abnormal in chest and abdominal radiographs (5.38, SD 0.9), and identifying gross bone or joint abnormalities in skeletal radiographs (5.29, SD 0.9). CONCLUSION: Medical students want to know how to look at radiographs, how to distinguish normal from abnormal, and how to identify gross abnormalities.

Adult↗

PubMed2006

Importance of pretest probability score and D-dimer assay before sonography for lower limb deep venous thrombosis.

OBJECTIVE: The purpose of our study was to develop and validate a clinical score (the Hamilton score) for the assessment of lower limb deep venous thrombosis (DVT) and to determine the usefulness of this score and a D-dimer assay before a complete lower limb sonographic examination. SUBJECTS AND METHODS: Five hundred forty-two consecutive ambulatory patients presenting to the emergency department were prospectively recruited, of whom 16 patients were excluded from the study. Eighteen history and examination variables were collected by the emergency department physicians. The Simplify D-dimer assay and a complete, single lower limb sonographic examination were performed in all patients. All patients with a negative sonographic examination for DVT were followed up for 3 months, and all those with a positive sonographic examination were given anticoagulation therapy. The Hamilton score was developed using the data from the first 214 patients and was prospectively validated in the next 312 patients. RESULTS: The most significant factors associated with a diagnosis of DVT were immobilization of the lower limb, active malignancy, and a strong clinical suspicion of DVT without other diagnostic possibilities by the emergency department physicians. Other factors were bed rest or recent surgery, male sex, calf circumference difference greater than 3 cm, and erythema. The Hamilton score was developed with the following weights: immobilization of the lower limb (2 points), active malignancy (2 points), strong clinical suspicion of DVT without other diagnostic possibilities by the emergency physicians (2 points), bed rest or recent surgery (1 point), male sex (1 point), calf circumference difference greater than 3 cm (1 point), and erythema (1 point). A score of 3 or greater indicates a likely probability for DVT, and a score of 2 or less represents an unlikely probability for DVT. Of the 103 patients with an unlikely probability Hamilton score and a negative D-dimer assay, only one patient had isolated calf DVT. A combined diagnostic strategy of unlikely-probability Hamilton score and a negative D-dimer would have a negative predictive value of 99% (95% confidence interval, 94.7-100%). CONCLUSION: An unlikely-probability Hamilton score and a negative Simplify D-dimer assay effectively exclude lower limb DVT, and a sonographic examination is unnecessary in this group of ambulatory emergency department patients.

Adolescent↗

PubMed2005

Radiology knowledge in new medical graduates in New Zealand.

AIMS: To establish the level of knowledge of new medical graduates in New Zealand about common radiological investigations and to assess their ability to request most appropriate, cost-effective radiological investigations for common clinical scenarios. METHODS: A test was developed and administered in Waikato, Christchurch, Rotorua, Auckland, and Dunedin hospitals during the first month of new house officer year (November 2002). RESULTS: Sixty-two first year house officers participated; 59 were New Zealand medical graduates (Auckland: 24 and Otago: 35) and 3 were from overseas institutions. The mean score for questions that assessed about risks involved in common investigations, including radiation, was 47% (95% CI: 45%-49%). The mean score for selecting the appropriate clinical investigations was 53% (95% CI 52%-54%). Most significantly, only 42% (95% CI 38%-46%) of the respondents thought they had adequate radiology teaching to work as house officers. The following percentage of the respondents never observed the respective examination during their medical school training: barium enema 72% (95% CI: 60%-82%); IVU 75% (95% CI: 63%-87%); US scan 25% (95% CI: 16%-37%); CT scan 20% (95% CI: 11%-32%); angiogram 16% (95% CI: 9%-28%); MRI 42% (95% CI: 30%-54%). The mean score for the practical knowledge about common investigations was 50 (95% CI: 48%-52%). CONCLUSIONS: Medical students report that they have limited exposure to radiology teaching during their medical school training. The test results suggest that medical school training enabled them to commence their probationary year with a 'just safe' level of radiology knowledge and skill.

Clinical Competence↗

PubMed2005

Deep venous thrombosis: withholding anticoagulation therapy after negative complete lower limb US findings.

PURPOSE: To establish the safety of withholding anticoagulation therapy after negative findings at a complete lower limb ultrasonographic (US) examination of the symptomatic leg for suspected deep venous thrombosis (DVT). MATERIALS AND METHODS: Regional ethics committee approval and patient consent were obtained. A total of 542 consecutive ambulatory patients presented to the emergency department and were prospectively recruited from April 2001 to May 2003. Of these patients, 16 were excluded, and radiology residents and sonographers performed a complete lower limb US examination by means of compression and Doppler US in 526 patients. Patients with negative US findings received no anticoagulation therapy, and they were observed for occurrence of any thromboembolic event for 3 months. Patients with progressive or new symptoms that were indicative of thromboembolism within the follow-up period underwent objective testing with US, computed tomographic (CT) pulmonary angiography, or both. RESULTS: There were 413 patients (78.5%) with US findings that were negative for DVT and 113 patients (21.5%) with findings that were positive. There were 64 patients (56.6%) with DVT isolated to the calf and 49 (43.4%) with proximal DVT. Of the 413 patients with negative initial US findings, 16 (3.9%) underwent a second US examination for new or progressive symptoms of DVT, one patient (0.25%) underwent CT pulmonary angiography for suspected pulmonary embolism, and one patient (0.25%) underwent both US and CT pulmonary angiography during the 3-month follow-up period. One of these patients (0.24%; 95% confidence interval: 0.01%, 1.3%) developed pulmonary embolism, which was diagnosed with CT pulmonary angiography. DVT was not diagnosed in any patient, and no patient died during follow-up. The negative predictive value of a complete single lower limb US examination to exclude clinically important DVT is 99.6% (95% confidence interval: 98.4%, 99.9%). CONCLUSION: A single negative complete lower limb US examination is sufficient to exclude clinically important DVT, and it is safe to withhold anticoagulation therapy after negative complete lower limb US findings were obtained in patients suspected of having symptomatic lower limb DVT. New or progressive symptoms require further objective imaging.

Angiography↗

PubMed2004

Circadian modulation of performance on an aversion-based place learning task in hamsters.

In golden hamsters, the expression of a reward-conditioned place preference (CPP) is regulated in a circadian pattern such that the preference is exhibited strongly at the circadian time of prior training but not at other circadian times. We now report that the same "time-stamp" phenomenon is expressed following context conditioning with an aversive stimulus (conditioned place avoidance, CPA). Animals that were trained at a specific circadian time to discriminate between a "safe" context and one paired with foot shock, showed strong avoidance of the paired context at 24 and 48 h following the last training session, and showed no avoidance at 32 and 40 h following training. Circadian time is a feature that is learned during conditioning even though timing itself is not an explicit discriminative cue in these experiments. The results suggest that in hamsters, the emotional valence associated with the place where arousing stimulation (rewarding and aversive) is encountered is highest at the circadian time of occurrence. The golden hamster may be predisposed to anticipate the recurrence of arousing events at circa-24 h intervals.

Animals↗

PubMed2004

Capillary electrophoretic and micellar electrokinetic separations of asymmetric dimethyl-L-arginine and structurally related amino acids: quantitation in human plasma.

We report the development of efficient electrophoretic methods for the separation and quantification of L-arginine and six naturally occurring derivatives that are structurally and functionally related. Capillary electrophoresis (CE) employing a concentrated borate buffer at pH 9.4 achieves the separation of mixtures containing dimethyl-L-arginine, NG-monomethyl-L-arginine, L-arginine, L-homoarginine, L-ornithine, and L-citrulline as 4-fluoro-7-nitrobenzofurazan derivatives. In addition, the separation of the isomeric dimethyl-L-arginine derivatives (symmetric and asymmetric) is attained with baseline resolution by micellar electrokinetic chromatography (MEKC) when a high concentration of deoxycholic acid is added as a surfactant to the same running buffer. The influence of buffer type, concentration, and pH on the separation was studied to optimize separation conditions. The limit of quantitation (LOQ) for asymmetric dimethyl-L-arginine in aqueous solution was determined to be 20 microM using UV absorption in a CE separation and 0.1 microM using laser induced fluorescence (LIF) detection in an MEKC separation. This newly developed method was successfully applied for the quantitation of asymmetric dimethyl-L-arginine and L-arginine in human plasma samples at levels that might be used as a clinical diagnostic for cardiovascular disease (0.125 microM LOQ).

4-Chloro-7-nitrobenzofurazan↗

PubMedDate not supplied

Does an immunochromatographic D-dimer exclude acute lower limb deep venous thrombosis?

BACKGROUND: A pre-test probability score and D-dimer may reduce the need for ultrasound examinations for excluding lower limb deep venous thrombosis (DVT). OBJECTIVE: To establish the accuracy of an immunochromatographic D-dimer assay called 'Simplify' for diagnosis of acute DVT by complete (calf veins included) lower limb ultrasound examination. METHODS: A total of 453 consecutive patients presented to the ED of a tertiary centre with suspected first episode of DVT, were prospectively recruited. A pre-test probability score (Hamilton Score), an immunochromatographic D-dimer and a complete, single, unilateral lower limb ultrasound examination were performed in all patients. All patients with a negative ultrasound examination were followed up for 3 months. RESULTS: There were 159 men and 294 women with a mean age of 55.8 years (SD 20.3). Of the 227 patients with a negative D-dimer, 214 patients had negative ultrasound examinations and 13 patients had isolated calf DVT. Among the 226 patients with a positive D-dimer, 74 patients had DVT and 152 patients had negative ultrasound examinations. The sensitivity, specificity, positive and negative predictive values were 85.1% (75.8-91.8), 58.5% (53.4-63.5), 32.7% (26.6-38.9) and 94.3% (90.4-96.9), respectively. One hundred and sixty-five patients had an unlikely Hamilton Score and a negative D-dimer. The negative predictive value of the immunochromatographic D-dimer in an unlikely Hamilton Score population was 98.8% (95.7-99.8%). CONCLUSION: An unlikely probability Hamilton Score and a negative immunochromatographic D-dimer reliably exclude both proximal and isolated calf DVT.

Adult↗