Search PubMed⌕ Search

Biomedical subjects

M R Chen

Publications and source records attributed to M R Chen.

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

Case report: agenesis of the right lung diagnosed by three-dimensional reconstruction of helical chest CT.

Unilateral pulmonary agenesis is extremely rare and the diagnosis can be made by a number of conventional methods. We report two cases: a 16-day-old girl and a 14-year-old girl presenting with tachypnoea in whom three-dimensional reconstruction of helical chest computed tomography was used to demonstrate the complete absence of the carina, right main bronchus and right lung. To our knowledge, these are the first cases of right lung agenesis diagnosed by this method.

Adolescent↗
PubMed1996

Use of bacterially expressed GST/EBNA-1 fusion proteins for detection of antibodies in sera from patients with nasopharyngeal carcinoma and healthy donors.

Epstein-Barr virus nuclear antigen-1 (EBNA-1) is a protein expressed consistently in EBV infected cells and in EBV related malignant tissues. Antibodies against EBNA-1 may therefore possibly be used as a marker for disease screening. Western blot analysis of serum antibodies was performed using GST (glutathione-S-transferase) fusion proteins containing different regions of EBNA-1 as antigens. Serum samples were collected from 38 patients with nasopharyngeal carcinoma (NPC) and 38 healthy individuals in Taiwan. All samples were found IgG positive for EBNA-1 when a truncated protein GST/E1 (70-102, 325-641) was used as the antigen. Thirty-three out of 38 NPC sera (86.8%) were positive for IgA antibody against EBNA-1. The positive rate was higher in comparison with IgA antibody against VCA (65.7%) or antibody against DNase (60.5%). Only 2.6% of sera from normal individuals were positive for an IgA response against EBNA-1. The major antigenic determinants for NPC serum IgA response were between amino acid(aa) 390 to aa 459 when different portions of EBNA-1 were used as antigens. The results suggest that IgA response against EBNA-1 could be used in combination with other EBV serology markers for NPC screening.

Animals↗
PubMed1995

Evolution of coronary artery pattern according to short-axis aortopulmonary rotation: a new categorization for complete transposition of the great arteries.

OBJECTIVES: We studied the correlation between coronary artery pattern and aortopulmonary rotation in complete transposition of the great arteries. BACKGROUND: Classifications of the coronary arteries in complete transposition are puzzling and incomplete. METHODS: Coronary artery anatomy and relation of the great arteries were identified at angiography, echocardiography, surgical intervention or autopsy in 76 patients with complete transposition from 1988 to 1993. Five main types (type 0 and Shaher types 1,2,4 and 9) and their similar variants of epicardial configuration were categorized into five patterns (O, I, II, IV and IX). In addition, data from 568 cases from published reports were collected for analysis. RESULTS: As the aorta rotated from a left anterior to a directly anterior location relative to the pulmonary trunk, the left anterior descending coronary artery arose from the left-hand sinus together with the right coronary artery (type 0, one case decreased to no cases); then it gradually shifted to the left to have the same origin as the left circumflex coronary artery from the right-hand sinus (type 1, 10 cases increased to 146, p < 0.0003). When the aorta rotated farther clockwise from directly anterior to right anterior (type 1, 146 cases increased to 235; type 2, 9 cases increased to 50, p < 0.0006) or from right anterior to right lateral (type 1, 235 cases decreased to 6 cases; type 2, 50 cases decreased to 20, p < 0.00000), the left circumflex coronary artery tended to move retropulmonically and originated from the left-hand sinus with the right coronary artery (type 2). When the aorta moved from right anterior to right lateral (type 2, 50 cases decreased to 20; type 4, 13 cases increased to 14, p < 0.031) or from right lateral to right posterior (type 2, 20 cases decreased to 1; type 4, 14 cases increased to 16, p < 0.0003), the right coronary artery shifted to the right-hand sinus anteaortically to join the left anterior descending coronary artery (type 4). Finally, the left anterior descending coronary artery combined with the left circumflex coronary artery (type 9, 12 cases increased to 21, p = 0.407) to become the usual pattern for normally related great arteries. Eta-square analysis showed that the evolution from pattern O to IX was dependent on clockwise aortopulmonary rotation. CONCLUSIONS: The coronary arteries in complete transposition of the great arteries can be classified into five patterns and their evolution deduced on the basis of aortopulmonary rotation. Dependence of coronary artery type on aortopulmonary rotation made it possible to anticipate the coronary pattern from the relation of the great arteries in transposition.

Adolescent↗
PubMed1994

Delineation of a 16 amino acid sequence that forms a core DNA recognition motif in the Epstein-Barr virus EBNA-1 protein.

EBNA-1 is the sole virally specified protein required for replication of the Epstein-Barr virus latency origin and also modulates its own expression. Both of these functions are mediated through specific DNA binding. We created a series of amino acid substitutions across the previously identified DNA-binding domain of EBNA-1 to further define the amino acids required for DNA recognition. The results of electrophoretic mobility shift assays using in vitro-translated EBNA-1 (aa 408-641) polypeptides indicated that: (i) The predicted alpha helical segment between aa 477 and 487 is not directly involved in DNA recognition but appears to contribute to a critical local polypeptide conformation. (ii) The positively charged residues Arg459, Lys460, and Lys461 are dispensable for DNA binding. (iii) The region between Gly462 and Lys477 contains residues important for DNA recognition. This region is extremely sensitive to mutation. The behavior of a synthetic peptide representing EBNA-1 aa 458-478 supported the mutagenesis data. A dimer form of this peptide, which lacks the predicted alpha helical domain, was capable of binding DNA, but only nonspecifically. The effect of binding affinity on transactivation was examined in cotransfection assays. EBNA-1 mutants with reduced binding affinity also demonstrated reduced levels of transactivation.

Amino Acid Sequence↗
PubMed1994

Angiographic classification of ventricular septal defects in tetralogy of Fallot.

The ventricular septal defect (VSD) in Fallot's tetralogy (TF) was classified into four types: perimembranous (PM), muscular outlet (MO), doubly committed subarterial (DS), and DS with perimembranous extension. From July 1990 to June 1992, we used angiocardiography to define preoperatively the types of VSD in 30 cases of TF, and correlated them with the operative findings. The angiographic images used to identify the types of VSDs were anteroposterior (AP) plus cranial tilting 20-30 degrees, right anterior oblique 30 degrees plus cranial tilting 30 degrees (elongated RAO view) and true lateral view of right ventricular (RV) angiography. DS type and MO type had a shadow of muscle bar postero-inferiorly in the AP and elongated RAO views, while perimembranous type and MO superiorly in the lateral view. DS with perimembranous extension type was devoid of both shadows. The results revealed 73% accuracy rate of prediction by angiocardiography. Most of the incorrectly predicted cases were attributed to a tiny inferior muscle bar in MO type and was mistaken as pm type VSD. We conclude that routine RV angiography before correction of tetralogy of Fallot to identify the types of VSDs is feasible. This information facilitates planning of surgical strategy.

Angiocardiography↗
PubMed1994

Subaortic blind mitral pouch in a double-inlet right ventricle.

A full-term baby girl was diagnosed at birth using echocardiography to have a single ventricle with common atrioventricular valve and subaortic ridge. On the 22nd day after birth she was admitted to hospital for intensive care after sudden onset of cyanosis. Three days later she died after repeated attacks of bradycardia. At necropsy the heart was examined by sequential segmental approach. Situs solitus with double-inlet right ventricle and ventriculoarterial discordance was revealed. The left atrial floor was separated from the ventricle by a small hole leading to a translucent blind pouch, which bulged toward the subaortic outflow tract with its hypoplastic tensor apparatus connected to the subaortic infundibulum. The aortic valve was normal. The pulmonary trunk with a competent bicuspid valve arose from the left-sided rudimentary left ventricle. The pulmonary blood flow was limited by a slit-like interventricular communication. Obstruction of the pulmonary venous return due to the natural closing of the patent foramen ovale and the mitral atresia led to her premature death.

Female↗
PubMed1994

Stability of HBV DNA in cell lines and nude mouse-passaged tissues derived from human hepatocellular carcinoma.

Human hepatitis B virus (HBV) infection has been closely linked to the occurrence of hepatocellular carcinoma (HCC). Hepatoma cell lines and nude mouse-passaged hepatoma tissues were used in this report to study the HBV DNA status in these cells after passage. DNA was extracted from seven hepatoma cell lines and three nude mouse passaged HCC lines. Southern blot hybridization technique was performed with either cloned HBV whole genome or subgenomic DNA fragments as probes to analyze the presence of HBV DNA. Integration of HBV DNA fragments was detected in one mouse passaged tissue, R. Hybridization with HBV subgenomic DNA revealed that there were some DNA rearrangements of the integrated HBV DNA in R. However, the integrated HBV DNA could not be detected in the cell line derived from R after in vitro cultivation for 2 years. Both episomal form and integrated HBV DNA were detected in a cell line NTU-h3. Episomal form HBV DNA ih NTU-h3 changed after several passages. HBV DNA in NTU-h3 was unstable after in vitro cultivation. Therefore, we concluded that the presence of HBV DNA might not be essential for the maintenance of the tumorigenicity of hepatoma and the nude mouse system was more stable for maintaining HBV DNA in HCC.

Animals↗
PubMed1993

Efficacy of plasmin-treated intravenous gamma-globulin for therapy of Kawasaki syndrome.

In order to delineate the efficacy of plasmin-treated intravenous gamma-globulin (IVGG) in the treatment of Kawasaki syndrome, we compared the frequency of coronary artery abnormalities in children treated or not with IVGG for Kawasaki syndrome. Among 291 cases of Kawasaki syndrome diagnosed during the period of 1987 to 1991 without coronary abnormalities within 10 days of the onset of illness, 128 were treated with IVGG and aspirin and were compared with 163 treated with aspirin alone. IVGG was given in a dosage of 400 mg/kg/day for 4 consecutive days. The detection of coronary abnormalities was monitored by two dimensional echocardiography. Two weeks after enrollment coronary artery abnormalities were present in 37 (22.7%) of 163 children in the aspirin group and in 9 (9%) of 128 in the gamma-globulin group (P < 0.05). Seven weeks after enrollment, abnormalities were present in 20 (12.3%) of 163 children in the aspirin group and in 6 (4.6%) of 128 in the IVGG group (P < 0.05). We conclude that plasmin-treated IVGG is effective in reducing the prevalence of coronary artery abnormalities in Kawasaki syndrome and suggest a predominant role of the Fc gamma fragment of IgG in the therapeutic effect.

Aspirin↗
PubMed1993

Separation of the complex DNA binding domain of EBNA-1 into DNA recognition and dimerization subdomains of novel structure.

EBNA-1 is essential for replication of the latent episomal form of the Epstein-Barr virus genome and is involved in regulation of viral latency promoters. EBNA-1 activity is mediated through direct DNA binding. The DNA binding and dimerization functions of EBNA-1 have previously been located to a carboxy-terminal domain, amino acids (aa) 459 to 607. To identify and define the subdomains for these two functions, we created an extensive series of deletions and point mutations in an EBNA-1 (aa 408 to 641) background. The ability of the EBNA-1 mutants to heterodimerize with a wild-type EBNA-1 (aa 459 to 641) Immunoprecipitation assays with a monoclonal antibody, EBNA.OT1x, that recognizes EBNA-1 (aa 408 to 641) but not EBNA-1 (aa 459 to 641). These experiments revealed that mutations affecting dimerization occurred over two separate regions, aa 501 to 532 and aa 554 to 598. DNA binding was tested in mobility shift assays against a panel of oligonucleotide-binding sites. Dimerization was a prerequisite for DNA binding. The DNA recognition domain was localized to a separate region, aa 459 to 487, upstream of the dimerization domain. EBNA-1 variants carrying substitutions at aa 467 and 468 and at aa 477 gave a pattern of binding to mutant oligonucleotide probes that implicates these particular amino acids in DNA recognition. EBNA-1 appears to utilize novel mechanisms for both DNA recognition and dimerization since neither domain conforms to previously described structural motifs.

Amino Acid Sequence↗
PubMed1993

Right pulmonary artery arising from ascending aorta: report of a successfully treated case.

A nine-day-old neonate presented with signs of congestive heart failure during the first week of life. The echocardiogram showed an early bifurcating great vessel originating from the left ventricle. In addition, there was another vessel originating from the right ventricle directly connected to the descending aorta without early branching into the bilateral pulmonary arteries. A muscular ventricular septal defect (VSD) was also found. Cardiac catheterization and angiography showed that: 1) the anomalous origin of the right pulmonary artery arose from the ascending aorta; 2) a large patent ductus arteriosus (PDA) connected the main pulmonary artery and the descending aorta; and 3) a muscular VSD existed. Magnetic resonance imaging also demonstrated the above findings. Reimplantation of the anomalous right pulmonary artery to the main pulmonary artery and ligation of the PDA were done. To the best of our knowledge, this very unusual case is the first such neonatal case with successful surgical repair in Taiwan.

Aorta↗
PubMed1993

Acute iron intoxication: a case report with ferric chloride ingestion.

A 24 y/o male, after attempting suicide by ingesting liquid ferric chloride, presented with protracted vomiting and epigastric pain. He was noted to have leukocytosis, a metabolic acidosis and an elevated serum iron level. Hemorrhagic gastritis, coagulation defects and an increase in urine beta 2-microglobulin, indicating renal tubular damages were found in the following day. He later recovered after treatment with deferoxamine and good supportive care. This is Taiwan's first reported case of acute iron intoxication in an attempted suicide. We discussed the characteristics of this liquid form of iron intoxication, the limitations of local laboratories in providing support and how to diagnose and treat acute iron intoxication without waiting for serum iron and total iron binding capacity levels. In conclusion, to evaluate the severity of iron intoxication, a deferoxamine challenge test and the severity of symptoms and signs should be assessed without relying only on serum iron and total iron binding capacity levels. Deferoxamine and good supportive care should be given to all serious iron intoxications.

Acute Disease↗
PubMed1991

Cloning and characterization of cDNA clones corresponding to transcripts from the BamHI G region of the Epstein-Barr virus genome and expression of BGLF2.

A cDNA library was constructed from poly(A)+ RNA isolated from the iododeoxyuridine-treated P3HR1 cell line. Five cDNA clones, which hybridized with the BamHI G fragment of Epstein-Barr virus (EBV) DNA, were subcloned and sequenced. Clones G2, G3 and G4 corresponded to the BGLF2 open reading frame (ORF) of EBV (B95-8, nucleotides 126,837 to 125,866); G3 was found to contain the entire BGLF2 ORF. The predicted Mr of the putative protein product of the EBV B95-8 BGLF2 ORF is 36K. Complete nucleotide sequencing of G3 revealed that there were two nucleotide changes from the reported sequence of the EBV B95-8 BGLF2 gene, but these did not alter the predicted amino acid sequence of the products. Clone G3 and a cDNA derived from it by N-terminal deletion were expressed in Escherichia coli, producing fusion proteins. Rabbit antisera against these proteins were shown to react with viral capsid antigen-expressing HR1 cells in an indirect immunofluorescence assay. In vitro transcription/translation products and fusion proteins expressed in E. coli were used to determine the presence of antibodies in sera from EBV-infected individuals. The results of immunoprecipitation and immunoblotting studies showed that the majority of EBV-seropositive individuals mount a serum antibody response to the BGLF2 ORF-encoded protein.

Amino Acid Sequence↗
PubMed1991

Familial aneurysms of the interventricular septum.

Congenital aneurysms of the interventricular septum were found in a 29 year old man and his four year old son. Both were symptom free. In both, M mode and cross sectional echocardiography showed an aneurysm in the mid-muscular trabecular portion of the ventricular septum with considerable paradoxical motion of the aneurysmal segment. Otherwise the chamber dimensions, intracardiac structures, and cardiac function were normal for age. Congenital aneurysm of the interventricular septum is rare and these familial cases may be unique.

Adult↗
PubMed1991

New monoclonal antibody against human cervical carcinoma with diagnostic and therapeutic potential.

A new murine monoclonal IgG3 antibody (Mab 1H10) was developed with specificity for human cervical carcinoma and several other tumor types. Antibody reactivity against a panel of tumor cell lines was examined by indirect immunofluorescence and quantified by flow cytometry. Mab 1H10 reacted with cervical, colorectal and bladder carcinoma cells and to a lesser extent melanoma and hepatocellular carcinoma cells but did not react with human fibroblasts, lymphocytes or RBCs. Mab 1H10, as assessed by immunohistochemical staining, bound 40/97 cervical carcinoma tissue samples, 8/16 colorectal carcinoma samples as well as a population of osteogenic sarcoma and lung, ovarian and bladder carcinoma tissues. Mab 1H10 did not react with any normal tissue or cell samples tested including cervix, ovary, breast, liver, colon, bladder, lung, spleen, cerebrum, lymphocytes or RBCs. Mab 1H10 may be useful for the targeting of drugs, toxins or radioisotopes to cervical carcinoma in humans.

Animals↗
PubMed1990

Molecular characterization of a cDNA clone encoding the Epstein-Barr virus (EBV) DNase.

RNA from IdUrd-treated P3HR1 cells was used for the construction of a cDNA library and screened with B95-8 EBV DNA BamHI fragment B and G probes. One clone, BG9, containing a 1.7 kb cDNA insert was further studied. Complete DNA sequence analysis revealed that BG9 encompassed the B95-8 EBV DNA sequences from nucleotide 120,747 to nucleotide 122,412 and corresponded to the BGLF5 open reading frame of the EBV DNase gene. Comparison of the sequences of BG9 with that of published B95-8 EBV DNA indicated that there were 14 different bases which results in 7 amino acid residue changes. The product of in vitro transcription/translation of a subclone, pGEM-BG9, contained the EBV DNase activity and a 52 kDa protein was immunoprecipitated from the in vitro translation products using serum from a patient with nasopharyngeal carcinoma which contained a high level of anti-DNase activity. Northern hybridization of P3HR1 RNA with the BG9 probe revealed a complex pattern of transcription in this region. Subgenomic DNA fragments were then used to map these RNA species to the B95-8 EBV DNA sequence. The result of S1 nuclease analysis indicated that a DNase ORF containing transcript sized 2.0 kb is initiated at nucleotide 122,435 +/- 1 and terminated at nucleotide 120,741 of the EBV genome.

Amino Acid Sequence↗