Biomedical subjects

Yu-Chun Wang

Publications and source records attributed to Yu-Chun Wang.

16 recordsLinked to original sources

PubMed2007

Improved transverse flow estimation using differential maximum Doppler frequency.

Conventional Doppler technique can only provide the axial component of the blood flow vector, which is actually a three dimensional (3-D) quantity. To acquire the complete flow vector, estimations of the other two velocity components are essential. For the two dimensional (2-D) Doppler-bandwidth-based transverse estimation, however, accuracy is generally limited because of the complex dependence of the Doppler spectral shape on the flow variation within the sample volume. Two factors that may lead to the Doppler spectral change were considered in this study. One is the position offset of the sample volume and the other is the length of the sample volume. Simulations were performed and experimental data were also collected. Results indicate that the position offset may result in severe underestimation of Doppler shift frequency. Consequently, Doppler bandwidth is overestimated when it is determined by the difference between Doppler shift frequency and maximum Doppler frequency. Compared with the position offset, influence of the length of sample volume on the Doppler bandwidth is minor. To overcome this problem, a novel method, which is based on the differential maximum Doppler frequency, is proposed. Specifically, two beams with different beam widths are simultaneously generated to observe the blood flow and the difference between the corresponding maximum Doppler frequencies is used to estimate the transverse velocity. It is demonstrated that the accuracy and stability of transverse estimation are significantly improved by the proposed method even when the position offset is present.

Blood Flow Velocity↗

PubMed2006

Extensive retroperitoneal and right thigh abscess in a patient with ruptured retrocecal appendicitis: an extremely fulminant form of a common disease.

As a disease commonly encountered in daily practice, acute appendicitis is usually diagnosed and managed easily with a low mortality and morbidity rate. However, acute appendicitis may occasionally become extraordinarily complicated and life threatening. A 56-year-old man, healthy prior to this admission, was brought to the hospital due to spiking high fever, poor appetite, dysuria, progressive right flank and painful swelling of the thigh for 3 d. Significant inflammatory change of soft tissue was noted, involving the entire right trunk from the subcostal margin to the knee joint. Painful disability of the right lower extremity and apparent signs of peritonitis at the right lower abdomen were disclosed. Laboratory results revealed leukocytosis and an elevated C-reactive protein level. Abdominal CT revealed several communicated gas-containing abscesses at the right retroperitoneal region with mass effect, pushing the duodenum and the pancreatic head upward, compressing and encasing inferior vena cava, destroying psoas muscle and dissecting downward into the right thigh. Laparotomy and right thigh exploration were performed immediately and about 500 mL of frank pus was drained. A ruptured retrocecal appendix was the cause of the abscess. The patient fully recovered at the end of the third post-operation week. This case reminds us that acute appendicitis should be treated carefully on an emergency basis to avoid serious complications. CT scan is the diagnostic tool of choice, with rapid evaluation followed by adequate drainage as the key to the survival of the patient.

Abscess↗

PubMed2006

Management of right colon diverticulitis: a 10-year experience.

BACKGROUND: Controversies abound as regards the optimal treatment for patients with diverticulitis of the right colon. METHODS: This is a retrospective review of 113 patients with a diagnosis of right colonic diverticulitis who received treatment at the China Medical University Hospital from July 1994 to June 2004. RESULTS: Medical therapy was undertaken in 56 patients diagnosed preoperatively with uncomplicated diverticulitis. All but one patient was successfully treated with bowel rest and antibiotics. Of the 51 patients with a preoperative diagnosis of acute appendicitis, 32 received appendectomy along with postoperative antibiotic therapy, 8 received diverticulectomy in addition to appendectomy, and 11 received colectomy. In all, 17 patients required right hemicolectomy or ileocecal resection due to diverticulitis-related complications or suspected malignancy. Of the 87 (56-1+32) patients who responded to conservative treatment, 11 developed recurrent diverticulitis. All 11 patients were successfully treated with medical therapy, and 2 subsequently received elective right hemicolectomy. Of the 9 patients who received medical treatment alone at the second attack, 2 suffered a third attack. Both were successfully managed with medical therapy. CONCLUSIONS: For uncomplicated diverticulitis of the right colon diagnosed preoperatively, antibiotic therapy with bowel rest is an effective treatment. Once it is encountered during surgery for presumed acute appendicitis, a conservative approach involving prophylactic appendectomy and postoperative antibiotics is recommended. For patients with recurrent diseases, medical treatment is still safe and efficient. Colectomy is indicated when complications occur or when malignancy is strongly suspected.

Adolescent↗

PubMed2006

Role of fundus-first laparoscopic cholecystectomy in the management of acute cholecystitis in elderly patients.

BACKGROUND: Conversion from laparoscopic cholecystectomy to open cholecystectomy leads to the loss of the advantages of this minimally invasive procedure and significantly increases length of hospital stay as well as cost. The conversion from laparoscopic to open cholecystectomy is more frequent among patients with acute cholecystitis and in elderly patients. This study evaluated whether fundus-first laparoscopic cholecystectomy could lower the conversion rate in geriatric patients with acute cholecystitis. MATERIALS AND METHODS: During a twelve-month period, 112 patients (36 of them age 65 years or older) underwent fundus-first laparoscopic cholecystectomy for acute cholecystitis in a tertiary care university hospital in central Taiwan. RESULTS: The conversion rate in the elderly patients was 2.7% (1/36). No major perioperative complications were observed. Minor complications--port-site infection and subhepatic fluid collection-occurred in two patients (5.5%). CONCLUSION: Laparoscopic cholecystectomy with a fundus-first approach is a safe, effective operative procedure for elderly patients with acute cholecystitis when performed by an experienced laparoendoscopic surgeon.

Aged↗

PubMed2005

Enhanced transformation and chemosensitivity of NIH3T3 cells transduced with hepatoma up-regulated protein.

Hepatoma up-regulated protein (HURP) is a recently identified novel cell-cycle-regulated gene. The HURP gene is overexpressed in human hepatocellular carcinoma and transitional cell carcinoma. The cellular function of HURP is not fully understood. In this study, the NIH3T3 cells transduced with the exogenous HURP gene manifested the general characteristics of tumor cells, which had higher growth rate in low-serum media and advanced ability of colony formation on agarose-based plates. Transduced HURP was capable of specifically enhancing the chemosensitivity of deoxycytosine analogs, such as gemcitabine, ARA-C, and 5-AZA-CdR, but neither had an effect on the response of DNA intercalating agents, such as cisplatin, carboplatin, and doxorubicin, nor on the response of microtubule stabilizers, such as paclitaxel, docetaxel, and vinblastine. These results indicate that the HURP gene might be a potential oncogenic gene and capable of enhancing the chemosensitivity of deoxycytosine analogs in NIH3T3 cells.

Animals↗

PubMed2005

Aurora-A overexpression associates with Ha-ras codon-12 mutation and blackfoot disease endemic area in bladder cancer.

Our data revealed that 59.4% of the bladder cancer specimens showed Aurora-A overexpression, of which 31.8% also had Ha-ras codon-12 mutation; 45.5% were from blackfoot-disease endemic areas in which arsenic exposure is a major environment factor associated with various cancer formation. We further demonstrated that arsenic treatment of the immortalized bladder cell line, E7, increased Aurora-A expression. All together, co-existence of Aurora-A overexpression and Ha-ras mutation suggests a possible additively effect on the tumorigenesis of bladder cancer. In addition, Aurora-A overexpression and up-regulated by arsenic exposure opens a new direction for exploring the occurrence of bladder cancer occurrence in Taiwan.

Arsenic↗

PubMed2005

Laparoscopic appendectomy using the LigaSure Vessel Sealing System.

BACKGROUND: Laparoscopic appendectomy is increasingly being employed to treat acute appendicitis. The aim of the present study was to evaluate the efficacy and safety of the LigaSure Vessel Sealing System (Valleylab, Boulder, CO) in laparoscopic appendectomy. PATIENTS AND METHODS: Laparoscopic appendectomy was performed using the LigaSure system in 15 patients who had a preoperative diagnosis of acute appendicitis. RESULTS: In two patients, the operation was converted to open appendectomy. The mean operative time was 47 minutes (range, 22-120 minutes). There was no evidence of any complications related to the use of the LigaSure system. Neither surgical endoclips nor an endostapler were used in any patient. CONCLUSION: Laparoscopic appendectomy using the LigaSure system is a safe and efficient procedure for acute appendicitis. Use of the LigaSure system in laparoscopic appendectomy may simplify the operative procedure and reduce the operative time.

Acute Disease↗

PubMed2005

Role of leukocyte count, neutrophil percentage, and C-reactive protein in the diagnosis of acute appendicitis in the elderly.

Leukocyte count, neutrophil percentage, and C-reactive protein (CRP) have been shown to give valuable information in the diagnosis of acute appendicitis. However, whether these laboratory tests have the same clinical applicability in the elderly as in young patients remains unclear. This retrospective study aimed to clarify the role of these tests in the diagnosis of acute appendicitis in patients aged 60 years or over. Eighty-five consecutive elderly patients underwent appendectomy for suspected acute appendicitis during a 30-month period. Histologically verified appendicitis was found in 77 of the 85 patients (90.6%). There was no significant difference in leukocyte counts or CRP values between patients with acute appendicitis and those with a normal appendix. The sensitivities of leukocyte count, neutrophil percentage, and CRP in the diagnosis of acute appendicitis were 71.4 per cent, 88.3 per cent, and 90 per cent, respectively, while the specificities were 37.5 per cent, 25 per cent, and 37.5 per cent, respectively. Of 77 patients with acute appendicitis, only two had all three tests simultaneously normal. In conclusion, patients with normal results in all three tests are highly unlikely to have acute appendicitis and should be evaluated with extra caution before surgery.

Acute Disease↗

PubMed2002

Liver abscess after non-operative management of blunt liver injury.

BACKGROUND: The non-operative management of blunt liver trauma can be applied in almost 80% of patients with this type of injury, with the advantages of the need for fewer blood transfusions, less intra-abdominal sepsis, and a better survival rate, than with the operative approach. However, liver abscess, as a known complication of the non-operative management of blunt liver trauma, is discussed infrequently. Therefore, we herein review our experience and describe this complication in detail. MATERIALS AND METHODS: From 1995 to 2001, 674 patients were admitted to our hospital due to blunt hepatic trauma. Among these patients, 279 underwent laparotomy and the remaining 395 patients were treated non-operatively. Twenty-two patients were identified as having liver abscess, with 16 of them belonging to the operative group, and six to the non-operative group. A retrospective review of these six patients and their characteristics, as well as pathogenesis, diagnosis, and the management of the liver abscesses, was conducted. RESULTS: These six patients were all male, with a median age of 19.5 years (range 3-24). The median injury severity score was 16.5 (range 9-25); three patients sustained grade-3 hepatic injury, and the other three were grade 4. The main diagnostic tool was abdominal computed tomography, and the abscesses took a median of 6 days (range 1-12) to form and be diagnosed. The abscesses were usually caused by infection from mixed organisms, and an abscess resulting from Clostridium infection developed within 1 day after injury. These abscesses were treated with antibiotics and drainage, and the median length of hospital stay was 26 days (range 8-44), without mortality or long-term morbidity. CONCLUSION: Liver abscess as a complication of the non-operative management of blunt hepatic trauma is a rare entity, with an incidence of 1.5% (6/395). It is usually seen in severe liver injury (grade 3 and above), but all our patients were all treated successfully, with no mortality. However, prolonged hospitalization may be required in this patient group.

Abdominal Injuries↗

PubMed2002

A cell line that secretes inducibly a reporter protein for monitoring herpes simplex virus infection and drug susceptibility.

A cell line modified genetically (Vero-ICP10-SEAP) that responds to infection by herpes simplex virus (HSV) was established. The cell line was constructed by stable transfection of Vero cell with a plasmid encoding the secreted alkaline phosphatase (SEAP) driven by the promoter of the HSV-2 ICP10 gene. Following infection with HSV, the stable line secretes a high level of the SEAP in the supernatants as measured by a chemiluminescence-based assay. The detection system is sensitive to an HSV titer as low as a single plaque-forming unit (PFU), with a linear range up to the equivalent of 2.5 x 10(4) PFU inoculum after infection for 24 h. There was no detectable enhancement in SEAP activities following inoculations with several viruses other than HSV. The Vero-ICP10-SEAP cell line was also utilized to develop an assay for determination of antiviral susceptibility given that the induced SEAP activity appeared to reflect the numbers of plaque. Evaluations of the stable line with representative acyclovir (ACV)-sensitive and-resistant HSV isolates demonstrated that their drug susceptibilities were determined accurately. In summary, this novel SEAP reporter system is a sensitive means for rapid diagnosis, quantitation, and drug susceptibility testing for HSV, with potential to the development of an automated assay.

Acyclovir↗

PubMed2002

Potential molecular marker for detecting transitional cell carcinoma.

OBJECTIVES: To assess the expression rate of a cancer-related gene, hepatoma-up-regulated protein (HURP), in the tumor tissue of transitional cell carcinoma (TCC), and to assess the potential suitability of using this gene as a novel molecular marker for detecting TCC in voided urine. METHODS: Total RNA was extracted from 80 TCC tissue samples of the urinary tract. Forty-five of the 80 tumor-adjacent tissue samples were from the same patients and 15 were from control subjects (patients with benign prostatic hyperplasia). The expression levels of HURP mRNA in these specimens were examined using reverse transcriptase-polymerase chain reaction. The HURP mRNA transcripts in voided urine pellets from 14 additional patients were determined using the same method. The messages were normalized to beta-actin mRNA. RESULTS: The detection of HURP expression in the TCC tissue samples had a sensitivity of 88.8% (71 of 80) and a specificity of 100% (15 of 15). Ten of the 45 grossly tumor-adjacent tissue samples expressed HURP mRNA, which may indicate subtle genetic changes in tissue adjacent to tumor. All seven urine specimens from the patients with TCC revealed HURP expression; however, no specimens from patients with nonmalignant diseases did so. CONCLUSIONS: A potential molecular marker for detecting TCC with tissue specimens and voided urine samples has been found. Although the real clinical application of this marker requires additional evaluation, the high sensitivity and specificity of the HURP gene amplification method warrants more investigation in the future.

Biomarkers, Tumor↗

PubMed2002

Determination of total mercury and methylmercury in human hair by graphite-furnace atomic absorption spectrophotometry using 2,3-dimercaptopropane-1-sulfonate as a complexing agent.

For the determination of total mercury in hair, an amount (25.0 mg) of hair sample was digested with conc. HNO3 (400 microl) at 90 degrees C for 10 min in a 7-ml teflon microreaction vessel. After digestion, the pH of the acidic hair mixture was adjusted to 5.0-6.0 by NaOH and was then passed through a clean-up Sep-Pak C18 cartridge. To the eluate, 2,3-dimercaptopropane-1-sulfonate (DMPS) and sodium acetate buffer (pH = 6.0) were added to form a mercury-DMPS complex. This complex was preconcentrated on two Sep-Pak C18 cartridges in series, and each cartridge was eluted with methanol and adjusted to 2.00 ml. A portion (50 microl) was introduced into a graphite cuvette and then atomized according to a temperature program. The method detection limit (MDL, 3sigma) was 0.064 (microg g(-1)); the calibration graph was linear up to 7.52 microg g(-1). Good accuracies were obtained when testing two human hair certified reference materials (GBW 09101 and BCR-397). Six real samples were analyzed, and the recoveries were 95.8 - 98.2% with a relative standard deviation (RSD, n = 3) < 2.1%. For the determination of methylmercury (CH3Hg+), 25.0 mg of hair sample was extracted with 2.0 mol dm(-3) HCl (1.0 ml) by ultrasonicating for 1 h. The supernatant solution was used for CH3Hg+ analysis and the hair residue was used for the analysis of inorganic mercury (Hg2+). The MDL of CH3Hg+ was 0.068 microg g(-1); the calibration graph was linear up to 6.00 microg g(-1). Six real samples were analyzed, and the recoveries were 96.0-99.2% with RSD (n = 3) < 2.3%. The sum of the concentrations of CH3Hg+ and Hg2+ was very close to that of the total mercury measured with a relative error within 3.6%. The proposed method can be accurately applied to the measurement of CH3Hg+, Hg2+, and total mercury in hair samples.

Hair↗

PubMedDate not supplied

Laboratory tests in patients with acute appendicitis.

BACKGROUND: Laboratory measurements such as leucocyte count, neutrophil percentage and C-reactive protein (CRP) concentration are commonly used as diagnostic aids in patients with suspected acute appendicitis. The present study aimed to clarify the role of these laboratory tests in diagnosing acute appendicitis. METHODS: The medical records of 897 patients who underwent appendicectomy for suspected acute appendicitis during a 30-month period were retrospectively reviewed. The laboratory findings were correlated with the histopathology of the excised appendices. Data were analysed to calculate the sensitivity and specificity of the individual tests, as well as the test combinations. RESULTS: Histologically verified appendicitis was found in 740 of the 897 patients (82.5%). The rise in leucocyte count and neutrophil percentage correlated with the degree of appendiceal inflammation. The median CRP level was much higher in the patients with ruptured appendicitis compared with that in patients with a normal appendix (96.8 vs 39.6 mg/L, P < 0.001). However, patients with uncomplicated appendicitis had a lower median CRP concentration than those with a normal appendix, although the difference was not statistically significant (24.1 vs 39.6 mg/L, P = 0.079). The sensitivity of leucocyte count, neutrophil percentage and CRP in diagnosing acute appendicitis was 85.8, 87.2 and 76.5%, respectively, whereas the specificity was 31.9, 33.1 and 26.1%, respectively. Of the 740 patients with acute appendicitis, only six had all three tests simultaneously within the reference interval. CONCLUSIONS: Abnormal laboratory findings cannot reliably deliver a diagnosis of acute appendicitis. However, acute appendicitis is very unlikely when leucocyte count, neutrophil percentage and CRP level are simultaneously normal.

Acute Disease↗

PubMedDate not supplied

Surface germicidal effects of ozone for microorganisms.

In this study the influences of microorganism species, relative humidity, and ozone dosage on ozone surface disinfection were evaluated. Bacterial and fungal cultures were spread on agar plates and exposed to ozone. The selected microorganisms included Escherichia coli, Bacillus subtilis, Candida famata, and Penicillium citrinum. Results showed that microorganism survival fraction and ozone dosage (ozone concentration times exposure time) have an exponential relationship. Results also indicated that E. coli was the most sensitive organism to ozone exposure. E. coli required only very low ozone doses of 2-2.5 and 3.5-4 mg to obtain 50 and 80% inactivation, respectively. In addition, P. citrinum was more resistant than E. coli and required ozone doses of 40-60 and 60-120 mg to obtain 50 and 80% inactivation. In addition, spores of B. subtilis were observed to be the most resistant organism, requiring ozone doses of 40-75 and 145-150 mg to obtain 50 and 80% inactivation. Yeast was less resistant than P. citrinum and B. subtilis, requiring ozone doses of 10 and 15-19 mg to obtain 50 and 80% inactivation. It was clearly indicated that the ozone dose differences for 80% microorganism inactivation could be as high as 40 times between B. subtilis and E. coli. Ozone surface germicidal efficiency increased as relative humidity increased, which could be related to more radicals generated from ozone reaction with more water vapor at higher relative humidity. It was concluded that ozone should be highly effective and provide a reliable safety factor in treating contaminated surface. In addition, workers might need to wear suitable respiratory protection at high ozone level operation.

Bacteria↗

PubMedDate not supplied

Prognostic significance of hepatoma-up-regulated protein expression in patients with urinary bladder transitional cell carcinoma.

We recently found a urinary molecular marker, Hepatoma-Up-Regulated Protein (HURP), for the detection of urinary bladder transitional cell carcinoma (TCC). In this study, the expression of HURP in 57 voided urine specimens was determined by semi-quantitative reverse transcriptase-polymerase chain reaction. HURP value was correlated with a variety of clinical parameters, including sex, age, tumor grade, stage, multiplicity, tumor shape and recurrence/metastasis during the follow-up period. The detection rate of HURP was 60.7% (17 out of 28) in voided urine of patients with TCC, 5.9% (1 out of 17) in non-TCC urological benign disease and 0% (0 out of 12) in healthy volunteers. HURP positivity (defined as above 0.1 cut-off value) was detected in 83.6% (92 out of 110) TCC specimens, 4.3% (1 out of 23) of non-TCC urinary cancer and 0% (0 out of 15) of benign urological disease. No relationship was found between the level of HURP and the above-mentioned clinical parameters other than recurrence of TCC patients. A higher level of tissue HURP was found in the patients having recurrence (Mann-Whitney U-test, p = 0.027).

Aged↗

PubMedDate not supplied

Comparison of the clinical presentations of ingested foreign bodies requiring operative and nonoperative management.

Foreign body ingestion is commonly seen in emergency departments. Although most cases have a clear history, foreign bodies in the gastrointestinal tract can be an unexpected finding after operations for other conditions. This study compares the clinical presentations and outcomes for patients requiring or not requiring operations. Between January 1998 and December 2001, 80 patients with foreign body ingestion were included and divided into two groups. Specifically, group 1 patients were managed nonoperatively, and group 2 patients were managed operatively. The patient demographics, symptoms, foreign body ingestion mechanisms, type of diagnostic studies and management, and outcomes were compared between the two groups. Group 1 contained 44 patients, and group 2 contained 36 patients. Group 1 patients were significantly younger, but the incidence of underlying disease and the proportion of patients who ingested foreign bodies intentionally or incidentally was similar in groups 1 and 2. Most of the ingested foreign bodies in group 1 were in the esophagus and stomach, but for group 2 patients they were mostly in the small bowel. Moreover, most of group 1 patients were asymptomatic, which was not the case in group 2. Most group 2 patients had no known history of foreign body ingestion, and diagnoses generally were established during surgery. Neither group of patients displayed any mortality. Nonoperative management of foreign body ingestion usually can succeed in asymptomatic patients with a clear history; however, ingested foreign bodies can cause serious problems for those patients without a clear history of foreign body ingestion.

Adolescent↗