PubMed Health⌕ Search

Biomedical subjects

S M Chuang

Publications and source records attributed to S M Chuang.

At least 19 recordsLinked to original sources
PubMed1992

Cloning and expression in Escherichia coli of the gene encoding an extracellular deoxyribonuclease (DNase) from Aeromonas hydrophila.

The gene encoding an extracellular DNase from Aeromonas hydrophila CHC-1 has been cloned and sequenced. Following expression of the dns in Escherichia coli, it was revealed that some of the cloned enzyme was present in the cell-free extracellular supernatant fluid, and there was no cell lysis and concurrent release of cytoplasmic or periplasmic proteins. Therefore, results suggest that E. coli cells were capable of secreting the DNase extracellularly, albeit very inefficiently. The dns is transcribed from its own promoter in E. coli, and expressed as a 25-kDa product, as determined by sodium dodecyl sulfate-polyacrylamide-gel electrophoresis of the culture supernatant preparations followed by a DNA-hydrolysis assay. Nucleotide sequence analysis predicted a single open reading frame of 690 bp encoding a 230-amino acid (aa) polypeptide, with a potential 20-aa signal peptide located at the N terminus of the predicted protein. The deduced aa sequence of the entire protein is highly homologous with that of the DNase of Vibrio cholerae.

Aeromonas hydrophila↗
PubMed1992

Cytogenetic study of acute lymphoblastic leukemia and its correlation with immunophenotype and genotype.

Among 72 Chinese patients with acute lymphoblastic leukemia (ALL), 50 had clonal chromosomal abnormalities. Structural abnormalities were detected in 42 patients: these included t(9;22) in 9, t(1;19) in 6, t(4;11) in 5, del(11)(q23) in 4, and del(6q) in 4. Adults had a higher incidence of t(9;22) and t(1;19) but a lower incidence of t(4;11) and hyperdiploid greater than 50 karyotype than children. A significant difference was also noted in white blood cell (WBC) count among various karyotypic groups. Patients with chromosomal abnormalities t(9;22), t(1;19), t(4;11) and del(11) (q23) had a shorter complete remission duration as compared with patients free of these abnormalities. Immunophenotyping was performed on 69 patients. All patients with t(9;22), t(1;19), and t(4;11) had B-lineage ALL restricted to certain stages of maturation: groups III and IV, groups IV and V, and group II, respectively (according to the classification of Foon and Tood). Among patients with t(9;22), t(4;11), and del(11)(q23), which have been considered to be associated with acute mixed-lineage leukemia, one each, respectively, showed myeloid antigen expression on the leukemic blasts (My+ ALL). No cross-lineage rearrangements of immunoglobulin (Ig) or T-cell receptor (TCR) genes were detected in these karyotypic subgroups of patients who underwent gene analysis.

Adolescent↗
PubMed1992

Characterization of Philadelphia-chromosome-positive acute leukemia by clinical, immunocytochemical, and gene analysis.

Philadelphia chromosome (Ph') was detected at presentation in 10 out of 110 patients with acute lymphoblastic leukemia (ALL) and five of 168 patients with acute myelogenous leukemia (AML). Two other ALL patients who had studies at relapse were also included in the analyses. One of the 12 Ph'-positive (Ph+) ALL patients had simultaneous expression of myeloid-associated antigen on the leukemic blasts, while all the five AML patients coexpressed markers of lymphoid cells. Double labeling of the cells with myeloperoxidase and CD10 on three Ph+ AML cases showed that most leukemic blasts expressed either myeloperoxidase activity or CD10 but not both. Cross-lineage gene rearrangements of T-cell receptor (TCR) beta-chain gene were detected in three of the eight Ph+ ALL patients tested. All the four Ph+ AML cases studied showed immunoglobulin heavy chain gene rearrangements, and three of them also had simultaneous rearrangements of TCR beta-chain gene. The results revealed that Ph+ acute leukemia in this study belonged either to ALL or mixed lineage leukemia, and none was pure AML. This finding is contrary to that of acute blast crisis of chronic myelogenous leukemia in which the majority of patients had myeloid transformation. Rearrangements of bcr were detected in four of the 10 Ph+ ALL and three of the four Ph+ AML patients tested. No significant difference was noted in the clinical or hematologic manifestations among Ph+ leukemia with or without bcr rearrangements.

Adult↗
PubMed1992

Prenatal cytogenetic diagnosis in amniocentesis.

From 1982 to 1990, cytogenetic studies were successfully conducted in 2,975 (96.19%) of the 3,096 pregnant women who underwent amniocentesis. The average maternal age was 33.7 years and the average gestational age was 18.1 weeks. Common indications of amniocentesis included advanced maternal age (AMA) (54.76%), previous fetus with chromosomal aberrations (6.82%) or gross anomalies (5.01%), intrauterine gross anomaly (4.97%) and maternal exposure to drugs or radiation (5.28%). Among the 89 cases (2.99%) with detected chromosomal aberrations, 53 were numeric (31 trisomies, 21 sex chromosome aberrations and one tripoidy) and 36 were structural (six de novo and 30 hereditary structural rearrangement). The incidence of chromosomal aberrations was 2.03% in cases with AMA. While only four of the 143 cases with previous fetal trisomy 21 had recurrence, the recurrent rate was 90.91% in 11 cases with previous fetal chromosomal translocation. Thirty (20.27%) of the 148 cases with abnormal sonograms showed chromosomal aberrations. Certain congenital anomalies are closely associated with cytogenetic changes: duodenal atresia and trisomy 21; cystic hygroma and 45,X; and polyhydramnios and trisomy 18. Only two of the 157 cases with indications of drug or radiation exposure had abnormal cytogenetic studies. Two of the 53 cases with detected numerical aberrations (47,XXY and 47,XXX) and 27 cases with hereditary structural rearrangement elected to continue their pregnancies. All of these babies were delivered without gross anomalies. This study suggests that for prenatal diagnosis. However, complementary measures, such as routine antenatal ultrasound and maternal serum alphafetoprotein, should be added to increase the efficacy of genetic amniocentesis.

Adolescent↗
PubMed1992

Neurenteric cyst at craniocervical junction: report of a case.

The authors report a rare case of neurenteric cyst at the foramen magnum presenting with a central cord syndrome and dysfunction of the lower cranial nerves. A magnetic resonance imaging study showed a cystic lesion over the lower medulla oblongata and C1-2 spinal cord. Differentiation between a neurenteric cyst and an epidermoid cyst was difficult. Successful total removal of the cyst was performed. The lesion consisted of an enteric cyst lined with a mucus-secreting columnar epithelium, containing highly proteinaceous supernatant and thick mucus deposit. The patient recovered dramatically after surgery.

Adult↗
PubMed1992

Rapid prenatal determination of fetal sex by polymerase chain reaction on amniocyte DNA.

Sex determination in early gestation is important for fetuses at risk for X-linked disorders or congenital adrenal hyperplasia. One hundred and seventy consecutive samples of amniocytes were collected between the 12th and 31st gestational week. Seven women received early amniocentesis before the 14th week. Fetal sex was determined by amplification of Y-specific DNA fragments within five hours. All results of the polymerase chain reaction, except for one false-negative, were compatible with cytogenetic analyses. Polymerase chain reaction of amniocyte DNA provides a rapid technique for sex determination in early gestation with high specificity and sensitivity.

Amniocentesis↗
PubMed1992

Malignant rhabdoid tumor arising from soft parts of the right thigh with unusual neurologic manifestation: report of a case.

A case of malignant rhabdoid tumor (MRT) arising from the soft tissue of the right thigh in a 49-year-old Chinese female with peripheral neuropathy is reported. The tumor, exhibiting the salient features of MRT, was composed of sheets and nests of polygonal cells with prominent nucleoli and characteristic paranuclear inclusion-like hyaline globules under light microscopy which corresponded to aggregates of intermediate filaments under electron microscopy. The results of immunohistochemical studies of the tumor cells were also characteristic: cytokeratin (+), vimentin (+), epithelial membrane antigen (EMA) (+), desmin (-), myoglobin (-), leukocyte common antigen (LCA) (-), kappa (-), lambda (-), IgG (-) and IgA (-). Serologic study revealed an M-component of IgA. The clinical evolution of the patient was highly aggressive and inevitably lethal. An adult malignant rhabdoid tumor is unusual, and its association with peripheral neuropathy and the coexistence of an M-component of IgA in this case appears to be unique. In this report, the differential diagnosis of histopathologic features, the association of peripheral neuropathy and the coexistence of an M-component of IgA are discussed.

Female↗
PubMed1990

Cytogenetic characterization of a nasopharyngeal carcinoma cell line and its subline.

Cytogenetic results of a nasopharyngeal carcinoma (NPC) cell line NPC-TW039 and its subline NPC-TW039-N1, established from the nude mouse transplant, were reported. This is the third case of NPC presented with banded karyotype, to date, in the literature. A 3q + marker chromosome, with involvement of band q25 similar to that present in the two previously reported cases, was detected in most tumor cells from both cell lines. The structural chromosome abnormalities of NPC-TW039-N1 were similar to its original cell line, NPC-TW039, except that the subline lost one marker chromosome and gained a new one.

Chromosome Aberrations↗
PubMed1990

Chromosome and bcr rearrangement in chronic myelogenous leukaemia and their correlation with clinical states and prognosis of the disease.

Among 77 unselected patients with chronic myelogenous leukaemia (CML), 70 had Philadelphia chromosome (Ph1) in blood cells. Extra chromosomal abnormalities were noted in 4%, 55% and 78% of Ph1-positive patients in chronic phase, accelerated phase and acute blast crisis, respectively. Rearrangement of the bcr was detected in 46 of 47 Ph1-positive patients studied and also in three of five Ph1-negative ones. The locations of the breakpoints were mapped to one of four zones of the bcr in 45 patients. The median duration from diagnosis of CML to onset of acute blast crisis was not significantly different between the two groups of patients with breakpoints in the 5' portion (34 months), and in the 3' portion (39 months) of the bcr. In addition, the locations of the breakpoints within the bcr did not change as the disease progressed in the six patients who had DNA analysed both in the chronic phase and subsequently in transformation. In one of them, an additional aberrant band which was not present in the beginning of the acute phase was detected in blood cells taken 2 months later. It is suggested from the studies that transformation of CML may not be related to alterations within the bcr.

Adolescent↗
PubMed1990

Establishment and characterization of two nasopharyngeal carcinoma cell lines.

Two human nasopharyngeal carcinoma (NPC) cell lines have been established. One derived from a 64-year-old male, and the other from a 36-year-old female Chinese patient living in Taiwan. Both were keratinizing squamous cell carcinoma in nature and designated as NPC-TW039 and NPC-TW076. Both have been grown in culture system for more than 100 passages. Single cells from both cell lines could form colonies in 0.3% soft agar. In the nude mouse transplantation experiment, both cell lines could produce tumor mass with metastasis. The karyotypic analysis showed multiple chromosomal abnormality. The number of chromosomes ranged between 76 to 109 and 80 to 105 with an average of 98 and 95, respectively. The doubling time was 10.5 hours and 10.8 hours, respectively. The NPC-TW039 cell line has been subcloned and three subclones have been obtained. Ultrastructural studies from those two cell line, three subcloned cell lines and two transplanted tumor masses, all showed two types of morphology: the dark and light cells. This morphologic difference is probably derived from the different metabolic state, but not due to an artifact. Three oncogene probes have been used to check the oncogene expression; none of those five cell lines is positive. Similarly, six Epstein-Barr virus fragments have been labeled to hybridize with NPC cellular DNA preparations, results from the Southern blotting showed no detectable Epstein-Barr virus DNA sequence.

Animals↗
PubMed1989

Cytogenetic evidence of multifocal origin of a unilateral retinoblastoma. A help in genetic counseling.

Retinoblastoma (Rb) occurs in two different genetic forms, hereditary and nonhereditary. Patients with nonhereditary Rb have unilateral, unifocal tumors, and those with the hereditary form usually have bilateral, multiple tumors. However, about 15% of patients with unilateral disease actually have multifocal tumors due to the hereditary form of Rb. Distinction between unilateral hereditary and sporadic Rb is very important both to the patient, who is at risk of later development of other malignancies, and to any future siblings and offspring. With only clinical data, the discrimination may be difficult. The cytogenetic detection of multiple unrelated clones in the tumor is very helpful for differential diagnosis because this finding strongly suggests the presence of a prezygotic germ cell mutation, which is heritable. A 23-month-old Chinese boy was found to have a single retinoblastoma at the right eye. Cytogenetic study of the tumor cells revealed three abnormal clones. Two of them were related, but the third one had completely different markers, suggesting a hereditary, multifocal origin of the tumor. None of the three clones showed an abnormality of 13q, which is present in about 21% of all Rb patients.

Chromosome Banding↗
PubMed1989

Chromosomal characteristics of Ph-positive chronic myelogenous leukemia in transformation. A study of 23 Chinese patients in Taiwan.

Cytogenetic study was performed in the past 3 years on 23 Chinese patients with Philadelphia chromosome (Ph) positive chronic myelogenous leukemia (CML) in transformation; seven were in accelerated phase and 16 in acute blast crisis. Chromosomal abnormalities in addition to Ph were found in three (43%) of the patients at accelerated phase and 14 (88%) of the patients at blast crisis. The common nonrandom chromosomal aberrations were double Ph, trisomy 8, trisomy 19, and trisomy 21, which occurred in 47%, 41%, 35%, and 29%, respectively, of the total patients with extra chromosomal abnormalities. Isochromosome for the long arm of chromosome 17 was found in only one patient. In patients with blast crisis, the type of blast cell was characterized through morphologic, cytochemical, and immunocytochemical studies. Eleven cases were classified as myeloid and five as lymphoid transformation. Trisomy 8, 19, and 21 were detected only in patients with myeloid blast crisis. This study also revealed a high incidence of trisomy 21 and a low incidence of i(17q) in Chinese patients with transformation of CML.

Adult↗
PubMed1989

Congenital mesoblastic nephroma: report of a case.

Congenital mesoblastic nephroma (CMN) is a rare renal tumor with a distinct pathology and a unique clinical, therapeutic, and prognostic pattern. The characteristic pathological feature is uniform mesenchymal spindle-shaped cells arranged in interlacing bundles. The prognosis of typical CMN is believed to be excellent by nephrectomy alone. We report a typical case of congenital mesoblastic nephroma which was prenatally detected, and was associated with maternal polyhydramnios.

Humans↗
PubMed1989

[The cat cry (cri du chat) syndrome: report of a case with review of 10 cases at the National Taiwan University Hospital].

The cat cry (cri du chat) syndrome is a rare congenital anomaly due to partial deletion of the short arm of the No. 5 chromosome. Since the first report of Lejeune et al, in 1963, nearly 400 cases have been reported. However, the syndrome with a ring chromosome is still very rare and only 10 cases were reported up to 1988, since the first report of Rohde and Tompkins in 1965. To investigate the chromosomal changes in the patients of cat cry syndrome, a chromosomal study was carried out on 10 cases of cat cry syndrome from 5,870 cases submitted to the Laboratory of Cytogenetics, National Taiwan University Hospital from Nov. 1968 through Apr. 1988. These ten cases included 3 males and 7 females (M:F = 1:2.3) aged 2 days to 18 months with an average of 5.5 months. The most common clinical features are: cat-like cry, growth failure, microcephaly with mental retardation, round face with facial abnormalities including hypertelorism, downward slanting palpebral fissures, micrognathia and low-set ears, and simian crease. Laryngomalacia or underdevelopment of the larynx may be a factor causing the cat-like cry. On chromosome analysis, 8 out of these 10 cases showed the usual simple deletion of the short arm of the no. 5 chromosome, and the other 2 cases revealed ring chromosome including a case of pure ring chromosome([(4, XY, r (5)] and a case of mosaicism with one ring chromosome, 2 ring chromosomes and simple deletion of the short arm of the No. 5 chromosome.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromosome Aberrations↗
PubMed1989

Human sperm chromosome analysis in primary infertility: a preliminary report.

Human sperm chromosomes can be analyzed using the zona-free hamster egg system. In order to familiarize ourselves with this new technique and to investigate the chromosome aberration frequency in fertile and possibly infertile men, we performed sperm chromosome analysis in 39 successful experiments. The subjects were divided into two groups. Group 1 was healthy men with proven fertility. Group 2 was husbands of couples with unexplained infertility. Semen samples were prepared freshly or preserved in TEST-yolk buffer for 12 to 72 hours. In group 1 using fresh samples, the mean penetration rate was 67.40 +/- 14.08% (mean +/- 2SD), the maturation index was 1.33 +/- 0.31. For samples treated with yolk buffer, the mean penetration rate was 91.34 +/- 7.42%, and the maturation index was 1.58 +/- 0.42. There was a statistically significant increase in penetration after yolk buffer treatment (p less than 0.001). In group 1 there were 89 haploid chromosomes, four were aneuploidy (4.5%), and three with structural aberrations (3.4%). In group 2, for fresh samples, the mean penetration rate was 71.34 +/- 27.96%, and the maturation index was 1.37 +/- 0.25. For samples treated with yolk buffer, the penetration rate was 86.33 +/- 25.18%, and maturation index 1.40 +/- 0.23. In group 2, there were 135 haploid chromosomes, 6 were aneuploidy (4.4%), and 4 with structural aberrations (3.0%). There was no statistically significant difference between group 1 and group 2 in the penetration rate, maturation index and frequency of chromosome abnormalities.

Chromosome Aberrations↗
PubMed1989

Heterotopic oral gastrointestinal cyst: report of a case.

Heterotopic oral gastrointestinal cyst, also called enterocystoma, is a rare choristoma composed of gastric and intestinal mucosa. Its origin is thought to be derived from misplaced embryonal rests. Clinically, it often causes swallowing and speaking difficulties. Surgical excision is the treatment of choice. Our reported case was a 16-month-old boy. He was noted to have a sublingual mass since birth, and was brought to our out-patient clinic due to gradual enlargement of the mass in the past month with swallowing and phonation difficulties. Surgical excision of the cyst was performed and microscopic examination revealed gastric mucosa and a variety of epithelial linings along the cyst wall. The patient had a good recovery after the operation.

Choristoma↗