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D Y Chang

Publications and source records attributed to D Y Chang.

At least 37 records · Page 2Linked to original sources
PubMed1996

The suitable treatment for adenocarcinoma in situ of uterine cervix: a report of four cases.

Adenocarcinoma in situ (AIS) of the uterine cervix is a rare disease. Some authors suggested that conization is a suitable treatment for AIS as for squamous cell carcinoma in situ. However, others did not agree. Four cases of AIS, from 1984 to 1994, have been diagnosed in the Hospital of National Taiwan University. If the diagnosis of the conization specimen showed AIS, abdominal total hysterectomy was performed days thereafter. The remaining uterine cervix was checked by histopathology to determine whether it was free of cancer lesions. AIS lesions remained in the uterine cervix, as shown by conization in two cases. AIS is not like lesion as squamous cell carcinoma in situ lesion which is easy to be removed by conization. It is suggested that conization is not an adequate treatment for AIS, rather, a total hysterectomy should be performed.

Adenocarcinoma↗
PubMed1995

Human signal recognition particle (SRP) Alu-associated protein also binds Alu interspersed repeat sequence RNAs. Characterization of human SRP9.

Nearly 1 million interspersed Alu elements reside in the human genome. Alu retrotransposition is presumably mediated by full-length Alu transcripts synthesized by RNA polymerase III, while some polymerase III-synthesized Alu transcripts undergo 3'-processing and accumulate as small cytoplasmic (sc) RNAs of unknown function. Interspersed Alu sequences also reside in the untranslated regions of some mRNAs. The Alu sequence is related to a portion of the 7SL RNA component of signal recognition particle (SRP). This region of 7SL RNA together with 9- and 14-kDa polypeptides (SRP9/14) regulates translational elongation of ribosomes engaged by SRP. Here we characterize human (h) SRP9 and show that it, together with hSRP14 (SRP9/14), forms the activity previously identified as Alu RNA-binding protein (RBP). The primate-specific C-terminal tail of hSRP14 does not appreciably affect binding to scAlu RNA. Kd values for three Alu-homologous scRNAs were determined using Alu RBP (SRP9/14) purified from HeLa cells. The Alu region of 7SL, scAlu, and scB1 RNAs exhibited Kd values of 203 pM, 318 pM, and 1.8 nM, respectively. Finally, Alu RBP can bind with high affinity to synthetic mRNAs that contain interspersed Alus in their untranslated regions.

Amino Acid Sequence↗
PubMed1995

Leiomyosarcoma of the broad ligament: a case report and literature review.

Solitary tumors of the broad ligament are rare. The most frequent solid tumor of the broad ligament is leiomyoma. Leiomyosarcoma of the broad ligament (LBL) is an extremely rare malignant tumor. Nine cases of leiomyosarcoma of the broad ligament had been reported previously. A 59-year-old woman with LBL is reported. Treatment consisted of resection and total abdominal hysterectomy with bilateral salpingo-oophorectomy. No evidence of metastasis is noted after 12 months follow-up. We conclude that the management of LBL is excision of the leiomyosarcoma as completely as possible and postoperative adjuvant chemotherapy.

Broad Ligament↗
PubMed1995

Independent clinical factors which correlate with failures in diagnosing early cervical cancer.

Our aim was to identify independent factors that correlated with colposcopically directed biopsy's reliability as a method for diagnosing early cervical cancer. One hundred ninety-one of a total of 2265 patients who had colposcopic examinations because of abnormal Papanicolaou smears were included in this study. These patients had all undergone a hysterectomy after being diagnosed as having cervical intraepithelial neoplasia grade III by colposcopically directed biopsy. By univariate analysis, old age (P = 0.0195), achievement of menopausal status (P = 0.0046), large lesion size (P = 0.0021), and unsatisfactory colposcopy (P = 0.0017) were found to be associated with the nondiagnosis of early cervical cancer. However, multivariate analysis using stepwise logistic regression revealed that large lesion size (P = 0.003) and unsatisfactory colposcopy (P = 0.0008) were the only independent factors that correlated with nondiagnosis. Our findings indicate that in order to reach a clear-cut diagnosis, cases with either unsatisfactory colposcopy or satisfactory colposcopy with large lesions (despite a lack of histologic evidence of invasions) should undergo a diagnostic conization.

Adult↗
PubMed1995

Adenomatoid tumor of the female genital tract.

OBJECTIVE: To remind gynecologists of the diagnosis of adenomatoid tumor of the female genital tract, a pathology which is often mistaken for leiomyoma, and in addition to warn of the malignant appearance of adenomatoid tumor. MATERIALS AND METHODS: During the study period from January 1988 to May 1994, the clinical features and pathologic findings of 25 cases of adenomatoid tumor of the female genital tract were reviewed at the National Taiwan University Hospital. RESULTS: The age of the patients ranged from 26 to 55 years with a median of 41 years. Adenomatoid tumor was an incidental finding during the surgical treatment of myoma (16 cases), cervical intraepithelial neoplasm (two cases), invasive cervical cancer (one case), adnexal cyst (five cases), and pregnancy with myoma (one case). Twenty-three cases had tumors in the uterine corpus and two in the fallopian tubes. Twenty percent of the patients had multiple tumors. Their sizes ranged from 1.0 to 8.0 cm. The case with the largest tumor measuring 8 cm in diameter is presented in detail. Its histologic, immunohistochemical and ultrastructural characteristics strongly support the mesothelial origin of adenomatoid tumor. CONCLUSION: Some different results were obtained than those hitherto reported in the literature, such as younger age, frequency of multiple tumors, and fewer cases accompanied by leiomyomas.

Adenomatoid Tumor↗
PubMed1995

Comparison of detection of human papillomavirus 16 DNA in cervical carcinoma tissues by Southern blot hybridisation and nested polymerase chain reaction.

An association between human papillomavirus (HPV) and cervical neoplasia has been widely reported and HPV DNA is commonly detected in cervical carcinoma tissues. However, estimates of the prevalence of HPV infection differs among various detection methods. Seventy cases of cervical carcinoma were screened for HPV 16 infection by Southern blot hybridisation (SBH) and nested polymerase chain reaction (PCR). According to SBH, the prevalences of HPV 16 DNA in stage I (n = 40) and stage II (n = 30) cervical carcinomas were 52.5 and 63.3%, respectively, and the overall prevalence was 57.1% (40 of 70). By nested PCR, the prevalences of HPV 16 infection in stage I and II cervical carcinomas were 87.5 and 93.3%, respectively, and the overall prevalence was 90.3%. The prevalence of HPV DNA detected by nested PCR was significantly greater than that detected by SBH. The combined concordance of positive and negative results between SBH and nested PCR was 61.4%. The discrepancy resulted mainly from 25 cases (35.7%) that were positive by PCR but negative by SBH. A small copy number of HPV DNA in the these 25 cases was documented by a semi-quantitative PCR method. The nested PCR was more sensitive than SBH and detected cases with low amounts of HPV DNA. The detection of HPV infection varied between these two prevailing detection methods and this should be kept in mind in assessing various epidemiological data concerning HPV infection.

Base Sequence↗
PubMed1995

A trinucleotide repeat-associated increase in the level of Alu RNA-binding protein occurred during the same period as the major Alu amplification that accompanied anthropoid evolution.

Nearly 1 million Alu elements in human DNA were inserted by an RNA-mediated retroposition-amplification process that clearly decelerated about 30 million years ago. Since then, Alu sequences have proliferated at a lower rate, including within the human genome, in which Alu mobility continues to generate genetic variability. Initially derived from 7SL RNA of the signal recognition particle (SRP), Alu became a dominant retroposon while retaining secondary structures found in 7SL RNA. We previously identified a human Alu RNA-binding protein as a homolog of the 14-kDa Alu-specific protein of SRP and have shown that its expression is associated with accumulation of 3'-processed Alu RNA. Here, we show that in early anthropoids, the gene encoding SRP14 Alu RNA-binding protein was duplicated and that SRP14-homologous sequences currently reside on different human chromosomes. In anthropoids, the active SRP14 gene acquired a GCA trinucleotide repeat in its 3'-coding region that produces SRP14 polypeptides with extended C-terminal tails. A C-->G substitution in this region converted the mouse sequence CCA GCA to GCA GCA in prosimians, which presumably predisposed this locus to GCA expansion in anthropoids and provides a model for other triplet expansions. Moreover, the presence of the trinucleotide repeat in SRP14 DNA and the corresponding C-terminal tail in SRP14 are associated with a significant increase in SRP14 polypeptide and Alu RNA-binding activity. These genetic events occurred during the period in which an acceleration in Alu retroposition was followed by a sharp deceleration, suggesting that Alu repeats coevolved with C-terminal variants of SRP14 in higher primates.

Animals↗
PubMed1995

Immunoelectrophoretic differentiation of alpha-fetoprotein in disorders with elevated serum alpha-fetoprotein levels or during pregnancy.

Our study aims to make differential diagnosis by immunoelectrophoresis for some common conditions with elevated levels of serum alpha-fetoprotein (AFP). One hundred and nine cases with elevated AFP levels were included in this study: yolk sac tumor (n = 8), hepatocellular carcinoma (n = 26), gastric cancer (n = 12), chronic hepatitis (n = 27) and normal pregnancy (n = 36). Lectin agarose gel electrophoresis, antibody-affinity blotting, and immunoreaction were used to identify the specific patterns of AFP in the respective conditions. The results showed that there were three possible bands: L1, L2 and L3. Yolk sac tumor produced a prominent L2 band and a light L3 band. Hepatocellular carcinoma produced a prominent L1 band and a light L3 band. Gastric cancer produced only an L1 band. Chronic hepatitis had a light L1 band and a pronounced L3 band. In pregnancy, the AFP pattern is similar to that of hepatocellular carcinoma. Immunoelectrophoresis is a useful method facilitating the differentiation of AFP origins.

Biomarkers, Tumor↗
PubMed1995

Torsion of an ovarian borderline tumor with extreme serum tumor markers: a case report.

A postmenopausal woman with torsion of the left ovarian mucinous cystadenoma with borderline malignancy is reported. Extremely elevated serum tumor markers such as carcinoembryonic antigen (CEA) (398.0 ng/mL, normal < 3.0 ng/mL), carbohydrate antigen 19-9 (CA 19-9) (240 U/mL, normal < 37 U/mL) and tissue polypeptide antigen (TPA) (1,918 U/L, normal < 110 U/L) were found preoperatively. Imaging studies such as ultrasound and computed tomogram favored a diagnosis of ovarian malignancy, and advanced ovarian cancer was suspected prior to operation. Diagnosis of borderline malignancy was first made by frozen section during laparotomy. The patient recovered following simple total hysterectomy and bilateral salpingo-oophorectomy. Serum levels of the tumor markers became normal gradually following operation. To present knowledge, this is the first reported case with extremely high serum tumor markers in a postmenopausal woman with torsion of a stage-Ia ovarian mucinous cystadenoma of borderline malignancy. Rapid release of these tumor markers into circulation secondary to necrosis and degeneration of the tumor cells following torsion might account for such an unusual finding.

Aged↗
PubMed1994

A human Alu RNA-binding protein whose expression is associated with accumulation of small cytoplasmic Alu RNA.

Human Alu sequences are short interspersed DNA elements which have been greatly amplified by retrotransposition. Although initially derived from the 7SL RNA component of signal recognition particle (SRP), the Alu sequence has evolved into a dominant transposon while retaining a specific secondary structure found in 7SL RNA. We previously characterized a set of Alu sequences which are expressed as small cytoplasmic RNAs and isolated a protein that binds to these transcripts. Here we report that biochemical purification of this protein revealed it as the human homolog of the SRP 14 polypeptide which binds the Alu-homologous region of 7SL RNA. The human cDNA predicts an alanine-rich C-terminal tail translated from a trinucleotide repeat not found in the rodent homolog, which accounts for why the human protein-RNA complex migrates more slowly than its rodent counterpart in RNA mobility shift assays. The human Alu RNA-binding protein (RBP) is expressed after transfection of this cDNA into mouse cells. Expression of human RBP in rodent x human somatic cell hybrids is associated with substantial increase in endogenous small cytoplasmic Alu and scB1 transcripts but not other small RNAs. These studies provide evidence that this RBP associates with Alu transcripts in vivo and affects their metabolism and suggests a role for Alu transcripts in translation in an SRP-like manner. Analysis of hybrid lines indicated that the Alu RBP gene maps to human chromosome 15q22, which was confirmed by Southern blotting. The possibility that the primate-specific structure of this protein may have contributed to Alu evolution is considered.

Amino Acid Sequence↗
PubMed1994

[Intestinal parasite and Clonorchis sinensis infection among the inhabitants in the upper stream of Taechong Dam, Kumgang (River)].

The prevalence of intestinal parasites and Clonorchis sinensis infection was observed among inhabitants in the upper stream of Kumgang (River) from January to October 1991. A total of 743 fecal specimens was examined by cellophane thick smear and formalin-ether concentration technique. The parasite positive rate including helminth eggs and protozoan cysts was 40.8%, the positive rates for every species were: Clonorchis sinensis 30.8%, Metagonimus spp. 14.5%, Fasciola spp. 0.7%, Taenia spp. 1.5%, Ascaris lumbricoides 0.4%, Enterobius vermicularis 0.1%, Hookworm 0.1%, Trichuris trichiura 1.6%, Entamoeba coli 0.7%, E. histolytica 0.3%, Endolimax nana 0.3%, Giardia lamblia 0.3% and Iodamoeba buetschlii 0.1%, respectively. The cumulative positive rate in Okchon-gun showed 51.1%, in the Kumsan-gun 50.8% and in the Muju-gun 28.6%. Through this survey, it was concluded that the soil transmitted intestinal parasites including helminthseggs and protozoan cysts have been decreased remarkably among the inhabitants along the upper stream of Taechong Dam, Kum-gang (River), on the other side, Clonorchis sinensis, Metagonimus spp. and Taenia spp. are still morderate prevalent.

Adolescent↗
PubMed1994

Loop electrosurgical excision procedure for conization of the uterine cervix.

The application of loop electrosurgical excision procedure (LEEP), a new method of conization of the uterine cervix used to diagnose cervical intraepithelial neoplasia (CIN) or cervical cancer is presented herein. A loop electrode consists of a thin wire that allows deep excision of the transformation zone (TZ). The cone-shaped tissue removed can be examined histologically. Over a period of one year, a total of 41 cases underwent LEEP. Without anesthesia, the patients did not have any noticeable pain during the procedure. There were no complications, such as fever, wound infection, massive bleeding or cervical stenosis. In low-grade CIN, follow-up colposcopy and cytology did not show persistence or recurrence. In two cases of high-grade CIN, subsequent hysterectomy revealed residual lesions on hysterectomized specimens. LEEP is a simple and quick procedure of diagnostic conization that can be done at the first visit without major complication. If the histopathology after LEEP is moderate- to high-grade CIN or invasive cancer, the conization cannot be regarded as a sufficient therapeutic procedure, and such a patient needs further treatment.

Biopsy↗
PubMed1993

A cellular protein binds B1 and Alu small cytoplasmic RNAs in vitro.

B1 and Alu are sequence-homologous interspersed elements of unknown function that have expanded in the genomes of mice and humans, respectively. A minority of B1 and Alu sequences are expressed as small cytoplasmic RNAs. These RNAs have conserved a secondary structure motif also present in signal recognition particle (SRP) RNA despite substantial sequence divergence, whereas random B1 and Alu sequences have not. This RNA structure has also been conserved by the source sequences that gave rise to successive transpositions during B1 and Alu evolution. In the present work small cytoplasmic B1 and Alu RNAs synthesized in vitro were found to bind a cellular protein by mobility shift and UV cross-linking analyses. The mouse and human proteins demonstrate the same specificity to a panel of competitor RNAs. Results using mutated B1 RNA indicate that a single strand loop in the conserved Alu motif is essential for binding. Previous work by Strub et al. (Stub, K., Moss, J. B., and Walter, P. (1991) Mol. Cell. Biol. 11, 3949-3959) demonstrated that the Alu-specific protein SRP 9/14 does not footprint to this region of SRP RNA. This observation coupled with the failure of anti-SRP/9 antibodies to identify SRP 9/14 in the B1 RNA-protein complex as well as the apparent mass and other characteristics of the protein described here suggest that it is a novel B1-Alu RNA-binding protein. Conservation of primary and secondary structure by B1 and Alu small cytoplasmic RNAs as well as features of their specific expression and ability to interact with the conserved binding protein indicate that these RNAs are more homologous than previously appreciated.

Animals↗
PubMed1993

Vulvar neoplasia associated with other primary malignancies.

It is recognized that a significant number of patients with vulvar neoplasia have had previous, concurrent, or subsequent genital tract neoplasia. This has resulted in speculation that there may be a common etiology and, in particular, of the possibility of an infection element. Among 59 cases of vulvar cancer diagnosed at the National Taiwan University Hospital from 1976 to 1991, there were seven cases (12%) associated with other primary malignancies. Carcinoma of the cervix was the most frequent other primary cancer (6/7, 86%). The possible role of human papilloma virus infection in genital neoplasia is discussed.

Adult↗
PubMed1993

The state of p53 in primary human cervical carcinomas and its effects in human papillomavirus-immortalized human cervical cells.

Wild-type (wt) p53 acts as a tumor suppressor, while certain mutant type (mt) p53 may exhibit 'oncogenic' function. We have recently demonstrated that human papillomavirus type 18 (HPV-18) E6 can partially overcome the growth-suppressive effects of wt p53, but it remains unclear what role p53 plays in cervical carcinogenesis. In this report, we have examined nine HPV-immortalized human cervical epithelial cell lines and 13 HPV-positive and two HPV-negative primary cervical cancers for p53 mutations by polymerase chain reaction--single-strand conformation polymorphism (PCR-SSCP). None of them contained p53 mutations in exons 5-9 where most p53 mutations in human tumors have been found. The entire p53-coding region of the two HPV-negative cervical cancers was sequenced and no mutations were noted. In order to examine the effects of wt p53 and mt p53 on HPV-immortalized human cells, we transfected HPV-immortalized cell lines with wt p53 and a mt p53 (mtp53Val-135). The results indicate that HPV-immortalized cells cannot tolerate large amounts of exogenous wt p53, while mt p53Val-135 can enhance transformation of these cells. The results support the notion that inactivation of wt p53 by E6 may be important for HPV-associated transformation and also suggests that mt p53 can act as an oncogene in HPV-immoralized human cells.

Base Sequence↗
PubMed1993

Cryptococcal infection of the vagina.

BACKGROUND: Cryptococcal infection is opportunistic and occurs most commonly in immunocompromised patients. Meningitis is the most frequent manifestation and causes marked morbidity and mortality. Other sites are less common. We report a case of vaginal cryptococcal infection. CASE: A 72-year-old patient who had undergone resection of the colon for cancer 9 years earlier was noted to have a suspicious lesion on the right vaginal wall after an abnormal Papanicolaou test. Biopsy of the lesion showed findings compatible with cryptococcal infection. Serial examinations revealed no evidence of systemic infection or immunocompromised condition. Empirical treatment was tried with fluconazole. Follow-up colposcopy showed almost complete disappearance of the vaginal lesion, and histologic section and culture of the tissue failed to reveal cryptococcus. CONCLUSION: Cryptococcal infection is rare, especially in a patient with no evidence of an immunocompromised condition. The preliminary result of fluconazole treatment was satisfactory. However, further follow-up and evaluation are needed to confirm the effectiveness of fluconazole in our patient.

Aged↗
PubMed1992

Anomalous effect of uncouplers on respiratory chain-linked transhydrogenation in Escherichia coli membranes: evidence for a localized proton pathway?

Energization of the pyridine nucleotide transhydrogenase in everted membrane vesicles from Escherichia coli JM83 was compared with the process in vesicles of the same strain transformed with the plasmid pDC21 overexpressing this enzyme. Proton translocation was assayed by the quenching of the fluorescence of the probe quinacrine. Agents able to discharge transmembrane proton gradients such as nigericin and the uncouplers 3,3',4',5-tetrachlorosalicylanilide and carbonyl cyanide m-chlorophenylhydrazone inhibited ATP-dependent transhydrogenation of NADP by NADH and discharged transmembrane proton gradients generated by transhydrogenation of AcNAD by NADPH, by oxidation of NADH, and by hydrolysis of ATP. This was observed in everted membrane vesicles of both strains JM83 and JM83pDC21. These strains differed significantly in the response of the NADH oxidation-dependent transhydrogenase. This reaction was inhibited by nigericin and uncouplers in membrane vesicles of JM83 but there was little inhibition or the reaction was stimulated in JM83pDC21, in spite of the discharge of the NADH oxidation-generated proton gradient measured by quinacrine fluorescence in the latter strain. It is proposed that the transhydrogenase is energized by direct or local (nonbulk phase) proton translocation in membranes of this strain. Uncouplers might facilitate these routes but would not discharge them. The generality of these observations was shown using other strains. NADH oxidase activity was severalfold lower in membrane vesicles of JM83pDC21 compared with JM83. The levels of ubiquinone and cytochromes, and the activities of NADH dehydrogenases I and II, and of cytochrome oxidase, were similar in the two strains. It is concluded that the NADH oxidase activity of JM83pDC21 is low because of the reduced rate of collision between electron-transferring complexes of the respiratory chain due to the large amount of transhydrogenase protein in the membranes of this strain. The large amount of transhydrogenase favors direct, nonbulk phase proton transfer. Transhydrogenase activity was stimulated by Ca2+, Mg2+, or Mn2+.

Cell Membrane↗