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Biomedical subjects

S Y Chang

Publications and source records attributed to S Y Chang.

At least 145 records · Page 8Linked to original sources
PubMed1997

Cloning of the human cDNA sequence encoding the NADH:ubiquinone oxidoreductase MLRQ subunit.

A cDNA clone encoding human NADH:ubiquinone oxidoreductase (complex I of mitochondrial respiratory chain) MLRQ subunit was isolated from human fetal liver cDNA library. The clone contained an open reading frame of 246 by which predicted a protein comprising 81 amino acids with a calculated molecular weight of 9,370 Da. The deduced amino acid sequence exhibited 95% homology (88% identity and 7% favored substitution) to that of bovine MLRQ subunit. Northern analysis revealed that the cDNA clone hybridized with a 0.7 kb mRNA species which was present in all tissues examined. The expression level of the 0.7 kb mRNA in heart, skeletal muscle, and brain was higher than in other organs. Human MLRQ cDNA could cross-hybridize with the genomic DNAs from various species.

Amino Acid Sequence↗
PubMed1997

Subsequent reproduction and obstetric outcome after methotrexate treatment of cervical pregnancy: a review of original literature and international collaborative follow-up.

The case reports of 22 patients with cervical pregnancies treated by methotrexate (MTX) administration and published in English literature between 1983 and 1995 were reviewed, by either original paper review or follow-up under international collaboration, to determine the subsequent reproductive performance and obstetric outcomes. Out of 22 cases, 18 (78%) MTX chemotherapy attempts succeeded with complete remission and four (22%) failed. Of the 13 women who wished to conceive and could be followed for at least 3 years, nine succeeded in having live births without congenital malformations, one spontaneously aborted and three suffered infertility. In general, MTX chemotherapy alone or combined with adjuvant methods such as subsequent cervical curettage or cervical tamponade, or intracervical potassium chloride injection, appears to be a convenient and effective method for the treatment of the majority of cervical pregnancies before 12 weeks gestation, and has not been shown to have detrimental effects on subsequent reproductive capacities, obstetric outcomes and progeny health for those cases with successful preservation of the uteri.

Cervix Uteri↗
PubMed1997

Conservative management of early endometrial adenocarcinoma with repeat curettage and hormone therapy under assistance of hysteroscopy and laparoscopy.

We report a rare case of early-stage endometrial adenocarcinoma in a 22 year old nullipara with polycystic ovaries undergoing conservative treatment. Pretreatment evaluation including tumour grade, depth of myometrial invasion, tumour size, hormone receptor status and flow cytometric analysis indicated a favourable prognosis. The patient underwent repeat endometrial curettage and a 6 month period of therapy with megestrol acetate and tamoxifen. A combination contraceptive pill was then prescribed to ensure withdrawal of the menstrual cycle thereafter. Now, 1 year after the last curettage, there is no evidence of disease. During the treatment period, hysteroscopy allowed for a more precise approach in panoramically examining the tumour nest in the endometrial cavity, and the subsequent endometrial response to hormone therapy. Laparoscopy using bulldog clamps applied to the isthmic portion of the Fallopian tubes prevented i.p. spread of endometrial tissue from retrograde regurgitation during hysteroscopy. Laparoscopic ovarian electrocautery resulted in the reduction of abnormal hypervascularization on the surface of polycystic ovaries postoperatively but caused a peri-ovarian adhesion complication. It is interesting that this case posed a unique opportunity to demonstrate the tumour regression under the assistance of laparoscopy and hysteroscopy.

Adenocarcinoma↗
PubMed1997

Transoral Teflon injection under flexible laryngovideostroboscopy for unilateral vocal fold paralysis.

Intracordal Teflon injection is a widely accepted method for the treatment of glottic incompetence due to unilateral vocal fold paralysis. It can be performed transorally via direct or indirect laryngoscopy, as well as transcutaneously under laryngovideoscopy. However, these procedures still have their disadvantages. The technique we introduce is to perform the procedure transorally while using a curved injection needle under flexible laryngovideostroboscopic monitoring. With topical anesthesia, the patient can phonate naturally during the procedure. The surgeon can visualize the needle and injection site clearly under high-resolution flexible laryngovideostroboscopy. Stroboscopic examination during surgery enables the surgeon to monitor the improvement of vocal fold vibration. Twenty consecutive patients treated with this technique were studied. The preliminary results are satisfactory. The technique we introduce is an outpatient procedure with high applicability and low morbidity. This technique is a good, cost-effective alternative to standard operative direct laryngoscopy with injection.

Adult↗
PubMed1997

Establishment of ANSI N13.11 X-ray radiation fields for personal dosimetry performance test by computation and experiment.

This paper describes establishment by computational and experimental methods of the American National Standard Institute (ANSI) N13.11 X-ray radiation fields by the Korea Atomic Energy Research Institute (KAERI). These fields were used in the standard irradiations of various personal dosimeters for the personal dosimetry performance test program performed by the Ministry of Science and Technology of Korea in the autumn of 1995. Theoretical X-ray spectra produced from two KAERI X-ray generators were estimated using a modified Kramers' theory with target attenuation and backscatter correction and their spectral distributions experimentally measured by a high-purity germanium semiconductor detector through proper corrections for measured pulse height distributions with photopeak efficiency, Compton fraction, and K-escape fraction. The average energies and conversion coefficients obtained from the computation and experimental methods, when compared with ANSI N13.11 and the recently published National Institute of Standards and Technology X-ray beams, appeared to be in good agreement--(+/-)3% between corresponding values--and thus, could be satisfactorily applied in the performance test of personal dosimeters.

Korea↗
PubMed1997

Immunohistochemical analysis of insulin-like growth factor I, insulin-like growth factor I receptor and insulin-like growth factor II in endometriotic tissue and endometrium.

BACKGROUND: The purpose of this study was to investigate unprecedentedly immunohistochemical localization of insulin-like growth factor I, insulin-like growth factor I receptor and insulin-like growth factor II in endometriotic tissue, and to compare staining intensity with that of endometrium obtained simultaneously. METHODS: Endometriotic and corresponding endometrial tissue samples were obtained during operative laparoscopy from eighteen infertile patients for the problem of infertility. Semiquantitative scoring was used for analysis of results. RESULTS: It was demonstrated that insulin-like growth factor I and insulin-like growth factor I receptor were present in both endometriotic and endometrial tissues. In contrast, there was little insulin-like growth factor II present in either ectopic or eutopic endometrial tissue. For insulin-like growth factor I and insulin-like growth factor I receptor, the immunostaining score was similar between ectopic and eutopic endometrial tissues. There was no significant difference in immunostaining score between glandular epithelium and stromal cells. CONCLUSIONS: insulin-like growth factor I and insulin-like growth factor I receptor could be demonstrated immunohistochemically in both endometriotic and endometrial tissues.

Adult↗
PubMed1997

The correlation of membranous glycoprotein-gp-170, cytoplasmic glutathione and glucose-6-phosphate dehydrogenase levels with multidrug resistance in transitional cell carcinoma cell lines of the urinary tract.

The expression of membranous glycoprotein gp-170, cytoplasmic glutathione (GSH) and energy-related glucose-6-phosphate dehydrogenase (G-6-PD) in cultured normal urothelial cells and transitional cell carcinoma (TCC) cell lines was analyzed by flow cytometric and enzymatic methods. The chemosensitivity of these tumor cells to four major types of anticancer drugs, including cisplatin, thiotepa, methotrexate, 5-fluorouracil, adriamycin and vinblastine, was correlated with biological activities in TCC cell lines. The TCC cell lines displayed a general sensitivity to anticancer drugs with a low incidence of highly resistant cell lines (23%). The expression of multidrug resistance was not related to cellular differentiation or invasiveness of cancer cells. Only 24% of TCC cell lines had an elevated expression of gp-170, but their expression was not related to drug resistance. Increased cytoplasmic GSH and G-6-PD was observed in over 90 per cent of TCC cell lines, but no correlation with drug resistance and cellular differentiation was observed. The biological activities of GSH and G-6-PD were not related to the drug resistance of TCC. The low expression rate of gp-170 in TCC cells indicates that other mechanisms should be involved in the development of MDR in TCC cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Color Doppler energy in prenatal diagnosis of meconium peritonitis: a case report.

Meconium peritonitis is an uncommon chemical peritonitis of a fetus resulting from antenatal bowel perforation. We reported a case of meconium peritonitis with pseudocystic formation diagnosed by color Doppler energy (CDE) at 34 gestational weeks. An echogenic substance inside a fetal abdominal mass was detected using ultrasound. By conventional color Doppler, there was minimal blood flow in the cystic wall or septums of the mass. Using CDE, bowel hyperperistalsis was observed in multiple small bowel loops and the region of intestinal loops into the mass was easily detected. Therefore, the angle independent nature of CDE will play a significant role in the early and accurate diagnosis of meconium peritonitis before birth.

Adult↗
PubMed1997

Vulvovaginal tuberculosis: a case report.

A rare case of vulvovaginal tuberculosis is reported. A 76-year-old woman presented with a painful ulcer at the posterior fourchette and lower vagina for 6 weeks. Direct biopsy for histologic examination revealed mycobacterial infection. Anti-tuberculosis treatment was effective for this patient. We suggest prompt biopsies for suspicious vulvar or vaginal lesions.

Aged↗
PubMed1997

Wide opening method for vocal fold retention cyst.

BACKGROUND: Vocal fold cyst is a common cause of dysphonia. In our reported series, most cases were retention cysts. Enucleation of the cyst under microlaryngoscopy is usually considered to be an ideal treatment despite the fact that cyst rupture is frequently encountered with this procedure. In this report, we present a wide opening method for vocal fold retention cyst. METHODS: Twenty consecutive patients with vocal fold retention cysts larger than 2 mm in diameter were operated upon using the wide opening method (marsupialization). The medial cyst wall was excised along with the overlying mucosa, while the lateral cyst wall was preserved on the vocal fold. The cyst was widely opened following this procedure. RESULTS: Perceptual voice improvement was noted postoperatively. Videostroboscopy and acoustic analysis were also applied to confirm the perceptual results. CONCLUSIONS: The wide opening method has the advantages of simplicity, minimal tissue injury, rapid functional recovery and low recurrence. This technique can be considered another standard treatment of choice for medium- or large-sized vocal fold retention cysts.

Adolescent↗
PubMed1997

Morphology and vibration pattern of the vocal cord after intracordal Teflon injection: long-term results.

BACKGROUND: Intracordal Teflon injection has been the mainstream management for unilateral vocal cord palsy over the past three decades. In recent years, some investigators concerned about its possible adverse effects on the vibration of the injected vocal cords. It is therefore necessary to clarify the clinical significance of these concerns if Teflon injection will stay as a viable treatment. METHODS: Twenty-one patients with unilateral vocal cord palsy, who had received Teflon injection for more than one year, were evaluated by flexible laryngovideostroboscopy, basic voice function evaluations and the patient self-assessment. RESULTS: The morphological and vibratory patterns of the post-injection vocal cords were categorized into seven types according to the videostroboscopic findings. Type I and type II cases had relatively normal morphology and vibration (assorted as group I). Type III through type VII cases showed various kinds of morphological and vibratory abnormalities (assorted as group II). Group I and group II were significantly different in the results of basic voice function evaluations and the patient self-assessment. Group I cases who showed relatively normal morphology and vibration had mean values closer to the normal ranges. For all the patients recruited, their voices were quite stable after injection. None with initial improvement of the voice suffered deterioration. CONCLUSIONS: The results showed that some patients had nearly normal vibration of the vocal cords years after Teflon injection. True (delayed onset, not due to improper injection) and voice-disturbing Teflon granuloma was not seen in the present study. The majority of cases with disturbed vibration were due to either improper location or an improper amount of injected Teflon. The problems were mostly induced by technical difficulties, not by Teflon-related foreign body reaction. Efforts should be made to avoid these technical errors to increase the predictability of the outcome.

Adult↗
PubMed1997

Bilateral multicystic kidney dysplasia in a fetus with neonatal pulmonary hyaline membrane disease: a case report.

Multicystic kidney disease is the most common cause of neonatal renal mass and either the most or second most common neonatal abdominal mass. This disease is a congenital dysplasia of the kidney characterized by large nonhomogeneous dilations of the collecting tubules. It may occur unilaterally or bilaterally, and the incidence is about 1 out of 5,000 to 10,000 births. Severe bilateral defects are lethal. Partial dysplastic involvement of both kidneys eventually leads to renal function impairment. This is a case of bilateral multicystic kidney dysplasia diagnosed prenatally at 34 weeks of gestation. Hyaline membrane disease was found in both lungs after delivery. The antenatal diagnostic criteria for multicystic kidney disease and treatment after diagnosis are also discussed.

Adult↗
PubMed1996

In vitro metabolism of a potent HIV-protease inhibitor (141W94) using rat, monkey and human liver S9.

Compound 141W94 (Vertex VX478) (3S)-tetrahydro-3-furyl N-[((S,2R)-3-(4-amino-N-isobutylbenzenesulfonamido)-1-benzyl- 2-hydroxypropyl] carbamate, is a potent HIV-protease inhibitor and is currently undergoing clinical trials. The purpose of this study was the rapid identification of the phase I and II in vitro metabolite of 141W94 using mass spectrometry. Four different sources of liver S9 fractions were used for studying comparative in vitro metabolism of 141W94. They were obtained from Arochlor-induced rat, normal (untreated) rat, cynomolgus monkey and human livers. Selected incubations were supplemented with uridine diphosphate glucuronic acid and the reduced form of glutathione. The predominant species seen in the incubation mixture was the parent compound 141W94. Metabolites arising from ring opening to form the diol and carboxylic acid and oxidation of the tetrahydrofurran ring (formation of dihydrofuran) were identified. In addition, of the two monohydroxylated products identified, one resulted from hydroxylation on the aniline ring and the other from hydroxylation at the benzylic position. Two different glucuronides were also observed. Comparing the three species, very little metabolism was seen in the normal (non-induced) rat. The metabolic profile and extent of metabolism with induced rat, monkey and human S9 was similar. Induced rat S9 incubation showed the formation of two unique metabolites that were not seen in non-induced rat, monkey and human S9 fractions. They were the monohydroxylated glucuronide and a carbamate cleavage product. The metabolites were identified using mass spectrometry based on their molecular masses and fragmentation patterns.

Animals↗
PubMed1996

The impact of the total motile sperm count on the success of intrauterine insemination with husband's spermatozoa.

PURPOSE: The purpose of this study was to evaluate the relationship between the total motile sperm count and the success of IUI treatment cycles with postwashed husband spermatozoa in couples with infertility in a large patient population. PATIENTS: When 939 couples underwent 1375 cycles of IUI with varying etiologies of infertility which included male factor, endometriosis, tubal factor, ovulatory dysfunction, uterine factor, cervical factor, and unexplained infertility, the results were 207 pregnancies. RESULTS: The overall pregnancy rate per cycle was 15.1% (207/1375). The total motile sperm count were significantly increased in the pregnant group than the nonpregnant group (38.7 x 10(6) versus 28.6 x 10(6); P < 0.001). There was a trend toward an increased success rate with increased total motile sperm count. Significance was reached when the total motile sperm count exceeded 5 x 10(6). Life table analysis was performed and the curve representing a cumulative chance of pregnancy calculated from our data reached 72%. CONCLUSIONS: Our findings suggest that a final postwashed total motile sperm count used for IUI may be considered predictive of the success for pregnancy and allow couples to be informed of the chances of success.

Female↗
PubMed1996

Modal behavior of the mu 1 Na+ channel and effects of coexpression of the beta 1-subunit.

The adult rat skeletal muscle Na+ channel alpha-subunit (mu 1) appears to gate modally with two kinetic schemes when the channel is expressed in Xenopus oocytes. In the fast mode mu 1 single channels open only once or twice per depolarizing pulse, but in the slow mode the channels demonstrate bursting behavior. Slow-mode gating was favored by hyperpolarized holding potentials and slow depolarizing rates, whereas fast-mode gating was favored by depolarized holding potentials and rapid depolarizations. Single-channel studies showed that coexpression of beta 1 reduces slow-mode gating, so that channels gate almost exclusively in the fast mode. Analysis of open-time histograms showed that mu 1 and mu 1 + beta 1 both have two open-time populations with the same mean open times (MOTs). The difference lies in the relative sizes of the long and short MOT components. When beta 1 was coexpressed with mu 1 in oocytes, the long MOT fraction was greatly reduced. It appears that although mu 1 and mu 1 + beta 1 share the same two open states, the beta 1-subunit favors the mode with the shorter open state. Examination of first latencies showed that it is likely that the rate of activation is increased upon coexpression with beta 1. Experiments also showed that the rate of activation for the fast mode of mu 1 is identical to that for mu 1 + beta 1 and is thus more rapid than the rate of activation for the slow mode. It can be concluded that beta 1 restores native-like kinetics in mu 1 by favoring the fast-gating mode.

Animals↗
PubMed1996

Epidermoid cysts of the testis: diagnosis by ultrasonography and magnetic resonance imaging resulting in organ-preserving surgery.

OBJECTIVE: To present experience in the diagnosis and management of patients with an epidermoid cyst of the testes and to confirm the role of conservative surgery. PATIENTS AND METHODS: The records from the last 26.5 years of patients diagnosed as having a testicular tumour were reviewed retrospectively. Those patients with a confirmed epidermoid cyst were evaluated for age, clinical assessment, methods of diagnosis, treatment and follow-up. RESULTS: Amongst a total of 131 testicular tumours, 11 patients (8.4%; mean age 25.7 years, range 21-35) were diagnosed pathologically as having an epidermoid cyst. Pre-operative suspicion of the benign nature of the lesions was supported by testicular ultrasonography in six patients and supplemented with magnetic resonance imaging (MRI) in one. An operation sparing the testicles was performed in eight patients after the diagnosis of epidermoid cyst was confirmed from frozen sections. Three patients were treated by radical orchidectomy. There were no relapses after a median follow-up of 47.3 months (range 2-82). CONCLUSION: In this series, the relative incidence of epidermoid cyst was higher than that reported in the literature (1-2%). Ultrasonography and MRI of the testes may allow the diagnosis to be made preoperatively. The absence of relapse in these patients further supports the use of organ-sparing surgery in these young men.

Adult↗