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Biomedical subjects

S-C Chen

Publications and source records attributed to S-C Chen.

30 records · Page 2Linked to original sources
PubMed2004

Clinical evaluation of the COBAS Amplicor HBV monitor test for measuring serum HBV DNA and comparison with the Quantiplex branched DNA signal amplification assay in Taiwan.

AIMS: To evaluate the performance characteristics and clinical usefulness of the COBAS Amplicor HBV monitor (COBAS-AM) test in Taiwan and to examine its correlation with the Quantiplex branched DNA signal amplification (bDNA) assay for measuring serum hepatitis B virus (HBV) DNA concentrations. METHODS: HBV DNA was measured by the COBAS-AM test in 149 sera from chronic HBV infected patients that had previously been analysed by the bDNA assay. RESULTS: The COBAS-AM test showed good reproducibility, with acceptable intra-assay and interassay coefficients of variation (1.6% and 0.9%, respectively) and good linearity (r2=0.98). The overall sensitivity of the COBAS-AM test was significantly higher than that of the bDNA assay (95.3% v 83.2%): 69.6% of samples with HBV DNA below the detection limit of the bDNA assay could be measured by the COBAS-AM test. There was a significant correlation between the results of the two assays (r=0.901; p<0.0001). On average, the results derived from the COBAS-AM test were 0.55 log lower than those of the bDNA assay. HBV DNA concentrations were significantly higher among HBV e antigen (HBeAg) positive patients than negative ones, and higher among patients with abnormal alanine aminotransferase (ALT) concentrations than those with normal ALT concentrations (p=0.0003). CONCLUSIONS: The COBAS-AM assay, more sensitive in HBeAg negative samples than the bDNA assay, can effectively measure HBV DNA concentrations in Taiwanese patients. HBV DNA values measured by the COBAS-AM test and bDNA assay correlate significantly.

Adolescent↗
PubMed2003

Fractalkine protein localization and gene expression in mouse brain.

Few chemokines are expressed constitutively in the brain at detectable levels; amongst them is fractalkine. We analyzed the distribution of fractalkine in the mouse brain with the aim of giving a neuroanatomical support to the study of its physiological function. To this end, we carried out an analysis of fractalkine protein localization and gene expression. An anti-fractalkine antibody was produced and used to perform an immunohistochemical study. The results indicated a high level of fractalkine protein in cortex, hippocampus, basal ganglia, and olfactory bulb. In particular, the presence of abundant immunoreactive neurons was observed in layers II, III, V, and VI of the cortex. In the hippocampus, the CA1 region was the most intensely labeled, but immunoreactive neurons were present also in CA2 and CA3, whereas in the basal ganglia, immunoreactive cells were observed in the caudate putamen. Other brain structures such as the brainstem showed a few scattered immunoreactive cells. The presence of fractalkine immunoreactive fibers was revealed only in the olfactory bulb and in the anterior olfactory nuclei. Gene expression study results, obtained by both semiquantitative PCR and in situ hybridization, matched protein localization with the highest levels of fractalkine transcript detected in the hippocampus, cortex, and striatum. The present study showed that fractalkine protein and mRNA are constitutively expressed at a high level in forebrain structure, but are almost absent in the hindbrain. Furthermore, localization at the cellular body level would suggest a paracrine or cell-to-cell interaction role for fractalkine more than a neurotransmission modulatory function.

Amygdala↗
PubMed2003

A head orientated wheelchair for people with disabilities.

PURPOSE: Most electric wheelchairs available on the market are joystick-controlled making people with hand or arm disabilities unable to control the wheelchairs easily. This study proposes a new head-orientated wheelchair design for people with disabilities. METHOD: This study involves a tilt sensor module fitted onto the operator's headgear that will sense head movements used to control the wheelchair's direction and speed. This system includes: the tilt sensor module, the signal processing circuit and a main controller. RESULTS: The average times required for completing experiments by seven volunteers using joystick-controlled and the newly developed wheelchairs were recorded. It was revealed that the difference in average operating time for the two wheelchairs were statistically insignificant (p>0.05). CONCLUSIONS: The wheelchair developed in this study, although not absolutely superior to the joystick-controlled method, should still provide a better alternative for people with disabilities unsuited to traditional input devices.

Adult↗
PubMed2003

Technical quality of root canal treatment in Taiwan.

AIM: To evaluate the current technical quality of root canal treatment (RCT) in Taiwan. METHODOLOGY: A total of 1085 RCT cases, randomly selected from a large sample and representative of the Taiwanese population from April to September 2000, were evaluated by eight endodontic specialists. The qualitative evaluation of RCT cases was based on two variables: length of the root filling and density of the obturation. A root canal with both adequate filling length (the apical termination of the root filling within 2 mm of the radiographic apex) and complete obturation (no lateral or apical canal lumen visible in the apical one-third of the root canal) was defined as having good-quality endodontic work (GQEW). A tooth was defined as having a GQEW when all its canals were categorized as GQEW. RESULTS: From a total of 1867 root canals, overfilling occurred in 235 (12.6%), adequate filling length in 1152 (61.7%), underfilling in 466 (25.0%) and no filling in 12 (0.6%). Of the 1867 root canals, 710 (38.0%) demonstrated complete obturation and 1157 (62%) demonstrated incomplete obturation. GQEW was found in 650 (34.8%) root canals and 329 (30.3%) teeth. The percentage of teeth with GQEW in hospital cases (38.1%) was significantly greater (P < 0.001) than that in private clinic cases (24.3%). In addition, the frequency of teeth with GQEW in the anterior teeth (40.4%) or in the premolars (33%) was significantly greater (P < 0.001) than that in the molars (18.4%). CONCLUSIONS: Approximately 70% of the teeth receiving RCT in Taiwan were either of inadequate filling length or sealing density.

Bicuspid↗
PubMed2003

Sonographic differentiation of invasive and intraductal carcinomas of the breast.

The purpose of this study is to evaluate the diagnostic ability of ultrasound and define the sonographic features of symptomatic intraductal and invasive breast carcinoma. To achieve this the ultrasound features of 488 invasive carcinomas and 65 non-screening detected intraductal carcinomas were compared retrospectively. The features included size, AP/W (anteroposterior diameter/width) ratio, shape, margin, internal echogenicity, internal echotexture, posterior acoustic transmission, bilateral edge shadowing sign and calcifications. The sensitivity and specificity of the detection of calcifications by ultrasound in comparison with mammography were also studied. The accuracy of ultrasound diagnosis is 92.0% for invasive carcinoma of breast and 84.8% for intraductal carcinoma. Differentiation of ultrasound features of intraductal and invasive carcinoma can be based on the internal hypoechogenicity, loss of bilateral edge shadowing, posterior acoustic transmission, irregular shape and non-uniform internal echotexture with odds ratio of 0.3, 0.3, 0.4, 0.5 and 0.5, respectively. Internal echogenicity was the only significant differentiating factor on multiple logistic regression analysis. Non-comedo type ductal carcinoma in situ can be differentiated from comedo type by irregular shape with odds ratio of 0.3. The sensitivity, specificity and accuracy rate for the detection of calcifications in invasive carcinomas by ultrasound were 65.1%, 61.9% and 63.2%; in comedo type intraductal carcinoma 62.5%, 66.7% and 63.6%, and in non-comedo type intraductal carcinoma 30.0%, 86.7% and 64.0%, respectively. The ultrasound appearance of non-screening detected intraductal carcinoma is relatively isoechoic in comparison with invasive carcinoma. More than 60% of microcalcifications in comedo type intraductal carcinoma can be accurately demonstrated by ultrasound. However, the role of ultrasound in detecting symptomatic intraductal carcinoma warrants further study.

Breast Neoplasms↗
PubMed2002

Retroperitoneoscopic nephropexy for symptomatic nephroptosis.

BACKGROUND: Open nephropexy for nephroptosis creates significant morbidity. We describe our technique for retroperitoneoscopic nephropexy and evaluate its efficacy. METHODS: Twenty-five renal units in 23 patients with symptomatic nephroptosis underwent retroperitoneoscopic nephropexy by suturing the posterior renal capsules and transfixing them to the back muscles. The diagnosis and postoperative assessment were made by typical symptoms (via patient questionnaire) and findings of intravenous urography (IVU) when the position was changed from supine to erect. RESULTS: Mean operative time was 188 min (range, 90-330). Mean narcotic use was 15.6 mg morphine. Complete resolution of symptoms occurred in 84% (21/25) renal units; 12% (three of 25) achieved partial improvement (>75% decrease of preoperative symptoms). Follow-up IVU showed that 88% of patients had a renal descent of <2 cm on standing; the others had a descent of 2-4 cm. All of the five renal units with hydronephrosis resolved completely after the operation. CONCLUSIONS: This modified technique of retroperitoneoscopic nephropexy is a minimally invasive, feasible, and highly successful option for treating patients with symptomatic nephroptosis.

Adult↗
PubMed2002

Prevalence and related risk factors of areca quid chewing among junior high students in eastern Taiwan.

Areca quid chewing is a serious problem in eastern Taiwan. The prevalence and related risk factors of areca quid chewing among junior high students were studied. Group 1 consisted of 896 non-aboriginal students and group 2 of 565 aboriginal students. The students were asked to fill out a questionnaire anonymously. Among the non-aboriginal students, 2.2% were found as current areca quid chewers, 16.4% had tried but not become regular users, and 2.2% had used it regularly and quit, whereas 9.7% of aboriginal students were current chewers, and 32.7% had tried it but had not become regular users, and 7.4% had used it regularly and quit. The prevalence of areca chewing is significantly different between boys and girls in the non-aboriginal group. A logistic regression analysis indicated that a non-aboriginal student who is a male, grows areca at home, is a tobacco smoker, an alcohol drinker, and has family members and close friends as chewers is more likely to chew areca quid than others. Aboriginal students who are chewers are likely to grow areca at home, are tobacco smokers and alcohol drinkers, and have family members and close friends as chewers. Based on the findings of the study, the need for a health promotion program was identified. Areca quid is not only detrimental to people's health, but also to the environment in which people live.

Adolescent↗
PubMed2002

Ultrasonography is superior to plain radiography in the diagnosis of pneumoperitoneum.

BACKGROUND: The aim of this study was to compare plain radiography with abdominal ultrasonography in the detection of pneumoperitoneum. METHODS: A total of 188 patients with suspected hollow organ perforation were studied. All patients had abdominal ultrasonography, upright chest radiography and left lateral decubitus abdominal radiography examinations. The sensitivity, specificity, positive and negative predictive value, and accuracy of chest and abdominal radiography were compared with that of abdominal ultrasonography. RESULTS: One hundred and seventy-eight patients underwent laparotomy; 170 patients had hollow organ perforation, five patients had perforated appendicitis and three had acute cholecystitis. In the diagnosis of pneumoperitoneum, ultrasonography had improved sensitivity (92 versus 78 per cent), negative predictive value (39 versus 20 per cent) and accuracy (88 versus 76 per cent), and similar specificity (both 53 per cent) and positive predictive value (95 versus 94 per cent) compared with plain radiography. CONCLUSION: Ultrasonography is more sensitive than plain radiography in the diagnosis of pneumoperitoneum.

Adolescent↗
PubMed2002

Sonographic features of phyllodes tumors of the breast.

OBJECTIVE: The aim of this study was to examine the sonographic features of phyllodes tumors of the breast. METHODS: Retrospective analysis of prospectively recorded sonographic features was performed on 2268 patients with phyllodes tumors or fibroadenomas during 1995-98. Data from 110 phyllodes tumors (76 benign, 11 borderline, 23 malignant) and 2204 fibroadenomas were analyzed. RESULTS: The patients with phyllodes tumors were older than the patients with fibroadenoma (mean +/- standard error, 39.7 +/- 1.1 years vs. 33.4 +/- 0.3 years; P < 0.0001). Sixty-four percent of patients with phyllodes tumors were aged 31-50 years, while 68.5% of those with fibroadenoma were aged 21-40 years. Phyllodes tumors were larger than fibroadenomas (5.90 +/- 0.43 cm vs. 1.95 +/- 0.03 cm; P < 0.0001). The ratio of length to anteroposterior diameter of phyllodes tumors was smaller than the ratio of length to anteroposterior diameter of fibroadenomas (1.72 +/- 0.06 vs. 1.89 +/- 0.02; P = 0.0105). Seventy-seven percent of phyllodes tumors were lobulated and 79.5% of fibroadenomas were oval. Lobulated shape of the tumor, heterogeneous echo pattern and absence of microcalcification are significant independent sonographic features in multiple logistic regression analysis to distinguish between phyllodes tumors and fibroadenoma. Benign, borderline and malignant phyllodes tumors displayed no significant differences in tumor size or the ratio of length to anteroposterior diameter. CONCLUSIONS: There is a substantial overlap in the sonographic characteristics between phyllodes tumors and fibroadenoma of the breast. If lobulation and heterogeneous hypoechoic internal echoes are observed and calcifications are absent, a diagnosis of phyllodes tumors should be considered. Sonography cannot distinguish between malignant, borderline and benign phyllodes tumors.

Adolescent↗
PubMedDate not supplied

Influence of posture change on intrarenal arterial resistive index measurement.

BACKGROUND: We investigated the influence of posture change on intrarenal arterial resistive index measurement in 80 subjects (38 male, 42 female). METHODS: Three interlobar arteries in the superior, middle, and inferior parts of the right kidney in each subject were examined by color Doppler ultrasound in two different positions (left lateral decubitus and supine). Based on the movement of the kidney caused by posture change, 23 subjects were classified as having a highly mobile kidney (group I) and the other 57 subjects were classified as not having a highly mobile kidney (group II). RESULTS: Fifty-eight kidneys (72.5%), 19 in group I (82.6%) and 39 in group II (68.4%), showed higher resistive index values in the lateral decubitus position than in the supine position. The influence of posture change on resistive index measurement was significant ( p < 0.001 for all subjects, p < 0.01 for group I, p < 0.05 for group II). The ranges of resistive index differences caused by posture change were 0-0.13 for group I and 0-0.11 for group II. The difference in resistive index caused by posture change was not significant between groups. CONCLUSION: Posture change is a potential confounding factor for intrarenal resistive index measurement.

Adult↗
PubMedDate not supplied

Application of SEMG in computer mouse access for the disabilities.

PURPOSE: To improve the operating speed of the traditional row-column scanning computer keyboard-mouse composite panel controlled using a single key. METHOD: Using a single mouse input control window can avoid scanning unnecessary keyboard characters, thereby increasing the speed in performing mouse commands. In addition, the surface electromyographic (SEMG) sensing input can also be used to provide an input option for the disabled. RESULTS: Eleven volunteers operated the single mouse input control window using the SEMG input and the traditional computer keyboard-mouse composite panel controlled using a single key. The average operating times were 121.3+/-8.9 sec and 208.6+/-10.7 sec, respectively. The difference was statistically significant (p<0.05). CONCLUSIONS: The row-column scanning method with the single mouse control window using SEMG input can effectively decrease the operating time. Through this system, the disabled can operate a computer and lead an independent life.

Adult↗