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Biomedical subjects

S Y Chang

Publications and source records attributed to S Y Chang.

At least 127 records · Page 7Linked to original sources
PubMed1998

Timed intercourse after intrauterine insemination for treatment of infertility.

OBJECTIVE: To compare the pregnancy rates, between intrauterine insemination (IUI) followed by timed intercourse and IUI only for treatment of the infertile couples. STUDY DESIGN: A prospective study of two different protocols of intrauterine insemination in two hundred and one infertile couples with a normal spermiogram was carried out. Of these, 101 couples were treated with IUI alone and 100 couples had both IUI and timed intercourse within a 12-18 h period. The pregnancy rates were compared between groups. RESULTS: The characteristics of the two groups were similar in terms of the mean age, as well as the duration and causes of infertility. The cycle characteristics following follicular stimulation were also similar between two groups. The pregnancy rate per cycle increased with increasing numbers of total motile sperm per insemination in the IUI alone group (P=0.045). Timed intercourse increased pregnancy rate in patients with lower motile sperm number (<40x10(6)) (27.7% versus 10.5%, P=0.023), but not in patients with higher sperm number (> or =40x10(6)) (25.7% versus 22.7%, P=0.671). CONCLUSIONS: In IUI with low number of motile sperm inseminated, timed intercourse significantly increases the pregnancy rates over IUI alone in infertile couples with a normal sperminogram. This alternative treatment appears to be a practical, simple, and inexpensive addition that improves the pregnancy rate in patients receiving ovulation induction and intrauterine insemination program.

Adult↗
PubMed1998

Transoral laryngeal surgery under flexible laryngovideostroboscopy.

Although direct microlaryngoscopic surgery is universally accepted as the standard procedure for endolaryngeal surgery, general anesthesia and direct laryngoscopy are necessary during the procedure. Suspended laryngeal position also impedes intraoperative functional monitoring. Transoral laryngeal surgery under indirect laryngeal mirror or telescope has the advantage of sparing general anesthesia and direct laryngoscopy, but lower precision, difficult manipulation, and a high patient cooperation requirement make the procedure of limited application. Trying to overcome the above shortcomings, transoral laryngeal surgery under flexible laryngovideostroboscopy (FLVS) is undertaken at our institute. The surgery is performed at an outpatient office under topical anesthesia, with the help of high-resolution fiberoptic stroboscopy, high-quality CCD videocamera, and monitor. From October, 1993 to March, 1996, 157 patients with selected laryngeal problems were operated upon using this technique, and 150 patients smoothly completed the procedure with satisfactory results. The technique is highly effective, especially for limited-manipulation, lower precision procedures and for patients who are not candidates for general anesthesia. With proper patient selection, this is a cost-effective surgery of low invasiveness and high applicability.

Adolescent↗
PubMed1998

Characterization and modulation of transitional cell carcinoma cell lines with acquired multidrug resistance.

OBJECTIVES: To characterize in vitro drug-induced multidrug resistance (MDR) in transitional cell carcinoma (TCC) cell lines, and to elucidate the possible mechanisms of acquired MDR and their modulation. MATERIALS AND METHODS: Two drug-resistant cell lines, TCC8702/A1000 (adriamycin 1000 ng/mL) and TCC8803/A200 (adriamycin 200 ng/mL), were established after long-term adriamycin treatment for at least 16 months. Their biological characteristics, including growth morphology, doubling time and cell cycle, were analysed. The drug-resistance pattern to various anticancer drugs was measured using a microplate cytotoxicity assay. The modulation of drug sensitivity by calcium-channel blockers and protein kinase C inhibitor was assessed among the different cancer cell lines. RESULTS: Both MDR sublines had lower growth rates, lower saturation densities and higher nuclear/cytoplasmic ratios than the parent cell lines. DNA staining and cell cycle analysis revealed that both TCC8702/A1000 and TCC8803/A200 cells had a decreased S-phase fraction and the TCC8803/A200 cells a changed stem line; both sublines showed increased expression of membranous glycoprotein gp-170. The cytoplasmic content of glutathione and glucose-6-phosphate dehydrogenase were not related to the MDR development in the sublines. The drug-resistance index of TCC8702/A1000 to adriamycin was 121-fold higher than the native cell line and TCC8803/A200 was 189-fold higher. TCC8803/A200 also had a broader MDR to cisplatin, vinblastine and vincristine. Calcium-channel blockers (verapamil, quinidine) and protein kinase C inhibitors (tamoxifen) inhibited gp-170 activity and slowed the drug-efflux pump, with the acquired-MDR cells subsequently accumulating anticancer drugs. A calcium antagonist-based combination of modulators all presented synergistic cytotoxic enhancement of the anticancer drugs. Parent TCC cell lines had a poorer response to modulator treatment than their MDR sublines. CONCLUSION: Different MDR mechanisms and subsequent modulator responses exist between native and acquired drug resistance in TCC cells. Acquired MDR seems strongly related to increased gp-170 expression and responds well to calcium antagonists. This phenomenon may be applicable in clinical conditions.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

The expression of mdr-1-related gp-170 and its correlation with anthracycline resistance in renal cell carcinoma cell lines and multidrug-resistant sublines.

OBJECTIVES: To clarify the role of the membranous glycoprotein gp-170 in renal cell carcinoma (RCC) cell lines and their multidrug resistant (MDR) sublines. and to correlate gp-170 with the natural and acquired drug resistance of these cell lines to anthracyclines. MATERIALS AND METHODS: The expression of gp-170 in five cultured RCC cell lines and serial RCC8701 MDR sublines was analysed by immunofluorescent flow cytometry. The chemosensitivity of these tumour cells to the anthracycline anticancer drugs adriamycin and epirubicin was measured using the microplate tetrazolium (MTT) cytotoxicity assay, and the results correlated with gp-170 expression. RESULTS: All six natural RCC cell lines showed a variably increased expression of gp-170, with the A704 and Caki-1 cell lines the highest. In contrast, gp-170 expression increased and then was suppressed in acquired MDR sublines of RCC8701 cultured in increasing concentrations of adriamycin. The A704 and Caki-1 cells were much more resistant to adriamycin and epirubicin than the A498, ACHN and RCC8701 cell lines, in parallel with the expression of gp-170. The resistant cell line cultured long-term in 800 ng/mL adriamycin, RCC8701/ADR800, was 122 times more resistant to adriamycin and 238 times more resistant to epirubicin than the parent cell line: the pattern differed from that in native RCC cell lines and was unrelated to the expression of gp-170. CONCLUSION: Membranous gp-170 plays an important role in MDR of native RCC cell lines, while acquired MDR cells have different mechanisms of obtaining drug resistance in addition to gp-170. This phenomenon may be applicable to the clinical treatment of patients newly diagnosed with RCC or those with disease refractory to chemotherapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

An internal control for routine diagnostic PCR: design, properties, and effect on clinical performance.

We constructed internal controls (ICs) to provide assurance that clinical specimens are successfully amplified and detected. The IC nucleic acids contain primer binding regions identical to those of the target sequence and contain a unique probe binding region that differentiates the IC from amplified target nucleic acid. Because only 20 copies of the IC are introduced into each test sample, a positive IC signal indicates that amplification was sufficient to generate a positive signal from targets present at the limit of test sensitivity. The COBAS AMPLICOR Chlamydia trachomatis, Neisseria gonorrhoeae, Mycobacterium tuberculosis, and human hepatitis C virus tests exhibited inhibition rates ranging from 5 to 9%. Approximately 64% of these inhibitory specimens were not inhibitory when a second aliquot was tested. Because repeatedly inhibitory specimens were not reported as false negative and because additional infected specimens were detected during retesting, test sensitivities were 1 to 6% greater than they would have been if the IC had not been used.

False Negative Reactions↗
PubMed1998

Survival advantages and complications of adjuvant therapy in early-stage cervical cancer with pelvic node metastasis.

BACKGROUND: Patients with early-stage cervical cancer who have pelvic node metastasis usually need adjuvant therapy after surgery for improvement of the length of survival. We attempted to determine the survival advantages and complications associated with different adjuvant therapeutic modalities. MATERIALS AND METHODS: Eighty-seven patients with clinical stage Ib and IIa cervical cancer were treated with radical hysterectomy from July 1986 through December 1994 were reviewed retrospectively. All had had lymph node metastasis. The patients were divided into three groups according to the different adjuvant therapeutic approaches utilized: radiation (group I, n = 43), chemotherapy (group II, n = 23), and chemoirradiation (group III, n = 21). RESULTS: There was no significant difference among these three groups in the 5-year relapse-free survival rate (group I: 63%, group II: 62%, group III: 51%, p = 0.785). The recurrence rates among these three groups were found to be similar (group I: 32.6%, group II: 39.1%, group III: 47.6%, p = 0.331). However, most of the recurrence in patients who had received pelvic radiation was at a distant site (group I: 79%, group III: 80%) as compared to the patients who had received chemotherapy only (group II: 33%), and the differences were significant (p = 0.020). The rates of complications, such as severe leukopenia, lymphedema with cellulitis, proctosigmoiditis and ileus, were found to be lower in the chemotherapeutic group. CONCLUSION: Although we failed to demonstrate the survival advantages of different adjuvant therapeutic approaches, we still favor chemotherapy as an adjuvant basis because it is the least toxic of the regimens.

Adult↗
PubMed1998

Unusual dental injuries following facial fractures: report of three cases.

We report 3 cases of unusual dental injuries following facial fractures. The first patient sustained intrusion of a maxillary incisor into the nasal cavity following a mandibular fracture. The tooth dislocated into the pharynx and was found lodged in the piriform fossa during surgery. The second patient sustained intrusion of molars into the maxillary sinus following maxillary and mandibular fractures. His treatment was delayed due to life-threatening hemorrhage. The third case involved ingestion of multiple avulsed teeth into the alimentary tract following severe maxillofacial fractures. Although the diagnosis was made more than a week after the injury, the patient did not suffer any complications as a result of the dental avulsion. The aim of this report is to emphasize the possibility of associated dental injuries in patients with facial fractures. The trauma surgeon should be cognizant of the importance of carrying out a thorough intraoral examination during the initial evaluation. Any missing tooth should be considered as possibly displaced into other tissue compartments, and must be routinely searched for with x-rays of the skull, cervical spine, chest, and abdomen. If full intrusion injury is suspected, further diagnostic investigation with facial computed tomography scanning may be worth while.

Adolescent↗
PubMed1998

Pregnancy after orthotopic liver transplantation in a Chinese patient: a case report.

A 28-year-old woman who had undergone orthotopic liver transplantation due to decompensated liver cirrhosis conceived 2 years after the operation. Immunosuppressive treatment was maintained during the pregnancy. The case was managed as high risk. Although intrauterine growth retardation arose in the third trimester, the patient finally gave birth to a healthy male baby. To our knowledge, the present case is the first successful pregnancy of an Asian woman after liver transplantation. The related problems are also discussed.

Adult↗
PubMed1998

Partial trisomy 13 [46,XY,dup(13)(q14-31)]: a case report.

We report a fetus with partial trisomy 13 [46,XY,dup(13)(q14-31)] which was found during an amniocentesis performed due to the age of the mother. This duplication segment (13q 14-31) has not been reported in literature. The clinical features of our patient included cleft lip/palate, low set ears, depressed nasal bridge, hypertelorism, and epicanthal fold. After termination of the pregnancy, the fetus was sent for an autopsy. The autopsy report was compatible with the gross findings and no other abnormalities, including central nervous, cardiac, and renal system, were found. The level of maternal alpha-fetoprotein, 2.67 MoM, was opposite with the common phenomenon in complete trisomy 13.

Adult↗
PubMed1998

Pathogenesis of ischemia reperfusion injury of the kidney after transient renal arterial clamping in rats.

Renal function can be severely impaired through injuries sustained after both short and prolonged periods of complete ischemia. The magnitude of renal dysfunction resulting from these conditions and their reversibility depend on the duration of anoxia. In this study, we used a Sprague-Dawley rat model (5 to 7 rats in each group) to study the pathogenesis of short-term ischemia (30, 60, and 120 min)/reperfusion (2, 4, 24 h, 1 wk, and 3 wk) injury of the kidney under warm (room temperature) or cold (4 degrees C) conditions. Ischemia was induced by clamping the renal artery. Changes in kidney weight, histopathology, concentrations of serum thromboxane and leukotriene, and tissue malonyldialdehyde (MDA) concentration, numbers of apoptotic bodies, and p53 expression in the kidney were compared with those of sham-operated rats. The results showed that the immediate increase in kidney weight due to inflammatory swelling was associated with simultaneous elevation of serum thromboxane and leukotriene levels. The changes in mediator levels were closely related to the duration of ischemia and temperature. Histologic structures were preserved better when renal artery clamping was done at 4 degrees C. MDA peroxidation products from the ischemic tissue prominently increased 1 week following ischemia; this paralleled a secondary increase in leukotriene levels. Flow cytometric detection of p53 oncoprotein showed a marked increase at 1 week following ischemia, which was accompanied by the development of apoptotic bodies in ischemic tissues. These changes were also closely related to the ischemic time and temperature during ischemia. This animal model may be useful for future studies of the prevention of ischemia/reperfusion injury of the kidney and for selection of effective antioxidants.

Animals↗
PubMed1998

Effect of postprepared sperm parameters and insemination specimen volume on the outcome of intrauterine insemination.

BACKGROUND: The purpose of the present study was to identify the postprepared sperm parameters affecting the outcome of intrauterine insemination and to find out whether the volume of insemination specimen was a determinant factor in the rate of successful conception. MATERIALS AND METHODS: A retrospective study including 306 couples was designed. The patients were inseminated with either 1.0 or 0.5 ml of prepared specimens. The pregnancy rates were compared using the chi-square test. Logistic regression was chosen for multivariant analysis of the parameters. RESULTS: The only parameter significantly affecting the success rate was the postprepared sperm motility (p = 0.033). The pregnancy rate was 27.91% in cases with > or = 95% sperm motility. Only two patients with less than 75% sperm motility conceived. The pregnancy rates in cases with 0.5 ml and 1.0 ml inseminations were 12.12% and 16.13%, respectively. This difference was statistically insignificant (p = 0.427). CONCLUSION: The postprepared sperm motility was the only parameter predicting the successful rate of intrauterine insemination. Seventy-five percent sperm motility can be used as a cut-off value for selecting patients. The volume of insemination specimen did not influence the outcome. Insemination with 1 ml of fluid was just as effective as insemination with 0.5 ml.

Female↗
PubMed1997

High-performance liquid chromatographic assay for the quantitation of irbesartan (SR 47436/BMS-186295) in human plasma and urine.

A selective, accurate, precise and reproducible high-performance liquid chromatographic assay was developed for the quantitation of irbesartan, an angiotensin II antagonist, in human plasma and urine samples. The method involved solid-phase extraction of irbesartan and internal standard (I.S.) using a 100-mg Isolute CN cartridge. A portion of the eluate was injected onto an ODS analytical column connected to a fluorescence detector that was set at an excitation wavelength of 250 nm and an emission wavelength of 371 nm. The mobile phase consisted of 50% acetonitrile and a 50% weak phosphate-triethylamine solution, pH 3.5, at a flow-rate of 0.8 ml/min. The assay was linear from 1 to 1000 ng/ml with both plasma and urine. In either matrix, the lower limit of quantitation was 1 ng/ml. The analyses of quality control samples indicated that the nominal values could be predicted with an accuracy >95%. The inter- and intra-day coefficients of variation for the analyses in both matrices were <8%. Irbesartan was stable in both human plasma and urine for at least seven months at -20 degrees C. The application of the assay to a pharmacokinetic study is described.

Administration, Oral↗
PubMed1997

Fast three dimensional sodium imaging.

An efficient scheme for fast three dimensional acquisition of sodium MR images is described. This scheme relies on the use of three dimensional k-space trajectories with constant sample density to achieve significant (60-70%) reductions in total data acquisition time over conventional projection imaging schemes. The performance of this data acquisition scheme is demonstrated with acquisition of sodium data sets on phantoms and normal human volunteers at 1.5 and 3.0 Tesla. The experimental results demonstrate that high quality three dimensional sodium images (0.2 cc voxel size, 10:1 signal-to-noise ratio) can be acquired at clinical field strengths (1.5 Tesla) in under 10 min.

Computer Simulation↗
PubMed1997

Spectrally weighted twisted projection imaging: reducing T2 signal attenuation effects in fast three-dimensional sodium imaging.

A scheme for the reduction of T2 signal attenuation effects in three-dimensional twisted projection imaging is presented. By purposely reducing the sample density at the high spatial frequencies, a considerable reduction in readout time is achieved. The reduction in readout time leads to decreased T2 signal attenuation which translates into improved signal-to-noise ratio (SNR). The SNR improvement is achieved without decreasing the image's resolution since the point spread function depends on the sample weighting as well as the T2 attenuation. The results indicate that SNR improvements of up to 40% can be achieved using the proposed scheme.

Brain↗
PubMed1997

The outcome of in vitro fertilization and embryo transfer therapy in women with endometriosis failing to conceive after laparoscopic conservative surgery.

STUDY OBJECTIVE: To compare the outcome of in vitro fertilization and embryo transfer (IVF-ET) after laparoscopic surgery in women with endometriosis with that of patients with tubal factor infertility. DESIGN: Retrospective survey of hospital and office charts using a computerized worksheet. SETTING: Lin-Kou medical center of Chang Gung Memorial Hospital. PATIENTS: Sixty-seven women with minimal to mild or moderate to severe endometriosis. Women with tubal factor infertility without other associated disorders (60 cycles) made up the control group. INTERVENTIONS: Seventy-five consecutive cycles of IVF-ET were performed in these patients who failed to conceive after laparoscopic conservative surgery. MEASUREMENTS AND MAIN RESULTS: The concentration of serum estradiol on the day of human chorionic gonadotropin (hCG) injection, the day of hCG injection, clinical pregnancy rates per transfer, number of follicles larger than 14 mm, number of embryos transferred, and implantation rate were not significantly different between women with endometriosis and those with tubal factor infertility. The number of oocytes retrieved and number fertilized were decreased, and the basal level of follicle-stimulating hormone on cycle day 3 was higher in women with both degrees of endometriosis. Women in both endometriosis groups received more follicle-stimulating hormone and human menopausal gonadotropin than those with tubal factor infertility. CONCLUSIONS: The outcome of IVF-ET in patients with endometriosis after laparoscopic surgery did not differ from that in the group with tubal factor infertility, but the former required more ampules of gonadotropin to achieve the same response. The advantages of laparoscopic surgery in women with endometriosis should be probably correlated with success of IVF-ET.

Adult↗
PubMed1997

Life table analysis of pregnancy rates in women with moderate or severe endometriosis comparing danazol therapy after carbon dioxide laser laparoscopy plus electrocoagulation or laparotomy plus electrocoagulation versus danazol therapy only.

STUDY OBJECTIVE: To assess the effectiveness, in terms of pregnancy rates, of isotopic 13CO2 laser laparoscopy versus traditional laparoscopy or laparotomy in the treatment of infertile women with moderate or severe endometriosis. DESIGN: Prospective 5-year study. SETTING: Medical school-affiliated hospital. PATIENTS: Three hundred nine infertile women with moderate to severe endometriosis. INTERVENTIONS: The patients were treated with one of four options: operative laparoscopy with the 13carbon dioxide (13CO2) laser vaporization and/or resection, operative laparoscopy with simple electrocoagulation and sharp dissection, laparotomy with electrocoagulation and sharp dissection, and medical treatment with danazol. Estimated cumulative pregnancy rates using life table analyses were indicators of treatment of success and compared among treatments. A subgroup of 192 women considered to have endometriosis as the only infertility factor was also evaluated. MEASUREMENTS AND MAIN RESULTS: Pregnancy rates in the laparoscopy group were equal to or higher than those of the laparotomy group, for both the entire population and the endometriosis-only subset. When the CO2 laser was used as an adjuvant option, the rates were better, especially in patients with advanced disease and with endometriosis as the only infertility factor. CONCLUSION: In women with endometriosis as the only infertility factor, laparoscopic surgery with the 13CO2 laser was more effective than nonlaser treatment.

Adult↗
PubMed1997

The techniques of nonmuscular closure of hypopharyngeal defect following total laryngectomy: the assessment of complication and pharyngoesophageal segment.

The usual method of reconstructing a hypopharyngeal defect during total laryngectomy includes pharyngeal muscle layer closure, which may result in high pharyngoesophageal pressure. We hypothesize that nonclosure of the pharyngeal muscle can reduce the pressure of the pharyngoesophageal segment which can reduce the chances of the formation of pharyngocutaneous fistulae. A technique of nonmuscular closure of a hypopharyngeal defect is presented. The differences in the rate of fistula formation and swallowing function between patients with usual and nonmuscular closure were also studied. Sixty consecutive laryngectomees were enrolled in this study. Thirty patients received usual closure after total laryngectomy, whereas the other 30 patients underwent non closure of their pharyngeal muscles. One patient (3.3 per cent) in the nonmuscular closure group and three patients (10 per cent) in the usual closure group developed a pharyngocutaneous fistula. The pharyngoesophageal pressures of the nonmuscular closure group were significantly lower than those of the usual closure group. We conclude that the technique of nonclosure of the pharyngeal constrictor muscle after total laryngectomy is relatively more simple and is not associated with a higher rate of fistula formation. Furthermore, nonclosure of the pharyngeal constrictor muscle is preferable to muscular closure because it reduces the spasm of the pharyngoesophageal segment which limits voice rehabilitation.

Cutaneous Fistula↗