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Biomedical subjects

S M Chuang

Publications and source records attributed to S M Chuang.

At least 55 records · Page 3Linked to original sources
PubMed1993

Rapid detection of Chinese G gamma+(A gamma delta beta)zero-thalassemia by polymerase chain reaction.

The Chinese G gamma+(A gamma delta beta)zero-thalassemia is caused by a deletion of more than 80 kilobases. It has a beta(+)-thalassemia phenotype and should be differentiated from other mutations causing beta-thalassemia. Using polymerase chain reaction with three oligonucleotide primers bridging the breakpoints, the deletion can be detected easily. The method is useful in the genetic counseling and prenatal diagnosis of the at-risk families.

Alleles↗
PubMed1993

Characterization of seven newly established nasopharyngeal carcinoma cell lines.

BACKGROUND: Nasopharyngeal carcinoma (NPC) has a relatively high incidence in Chinese living in Taiwan, Hong Kong, Singapore, and South China. To better understand this cancer, we have established several new NPC cell lines. EXPERIMENTAL DESIGN: We collected biopsy specimens from suspected NPC patients and divided each specimen into two parts: the first part was fixed for routine histopathologic examination, and the other part was put into culture medium for primary culture. Once the cell lines were established, they were extensively characterized. RESULTS: Seven NPC cell lines were established, and all have been passaged more than 100 times. Two lines were derived from keratinizing carcinomas and five from undifferentiated carcinomas. Electron microscopic examination revealed that both dark and light tumor cells contained intermediate filaments with clear desmosome formation. The average doubling time ranged from 10.7 to 16.3 hours. Karyotypic analysis showed multiple chromosome abnormalities with the average chromosome number between 84 and 95. Colony forming efficiency in soft agar was 18-42%. All cell lines could induce solid tumor mass formation when transplanted into nude mice, and the histopathological findings showed two keratinizing and five nonkeratinizing carcinomas. All cell lines contained less acidic keratin polypeptides than basic keratin polypeptides. Strong expression of vimentin in each single cell of all cell lines was also observed. The oncosuppressor retinoblastoma gene in each cell line showed no remarkable abnormality, but retinoblastoma protein was abnormally expressed in some interphase cells. The oncogenes, erbB and c-fgr, were both normally expressed. While the c-myc oncogene in all cell lines was overexpressed when compared with the Burkitt's lymphoma Raji Cell line, the c-myc DNA sequence in each cell line showed neither amplification nor rearrangement. CONCLUSIONS: The newly established seven NPC cell lines have been well characterized, and all showed overexpression of c-myc oncogene. The oncosuppressor retinoblastoma gene revealed no remarkable rearrangement, but its protein product was abnormal in certain interphase cells of each cell line.

Adult↗
PubMed1993

Clinical characteristics of congenital hypothyroidism detected by neonatal screening.

Various clinical features have been prospectively evaluated in 18 infants with congenital hypothyroidism detected by the National Taiwan University Hospital screening program from January 1990 to May 1991. During the same period of time, 24 suspected cases with normal thyroid function at referral were similarly evaluated and used as controls. Among the various clinical features evaluated, there were statistically significant differences between the two groups for the following five items: feeding problems, constipation, dry skin, umbilical hernia and enlarged posterior fontanel. However, these findings were subtle and nonspecific. Even when the neonatal hypothyroid index (Quebec) was used for evaluation, only one-half of these hypothyroid babies had scores of more than two. On the other hand, there was a statistically significant difference in the thyroid function test between the two groups whether it was determined from the filter paper spot or the serum. Our observations clearly demonstrate the difficulty in establishing a diagnosis of congenital hypothyroidism on clinical grounds only at an early age of life. This study also emphasizes the importance of biochemical screening in the early detection and treatment of hypothyroid infants.

Age Factors↗
PubMed1993

Rapid detection of human hemoglobin Quong Sze by polymerase chain reaction.

Human hemoglobin Quong Size is a nondeletional defect involving codon 125 of the alpha 2-globin gene. The molecular defect is a T to C mutation, therefore, a new MspI site (CCGG) is created. Using a pair of flanking DNA primers and polymerase chain reaction, a DNA fragment of 339 basepairs (bp) was amplified. After MspI restriction and gel electrophoresis, the mutation could be clearly identified by the presence of two fragments, 108 and 123 bp. This method is rapid and simple and will be very useful in the genetic counseling of Southeast Asians, including the Chinese, in which nondeletional alpha-thalassemia defects are common.

Base Sequence↗
PubMed1993

Norplant-2 subdermal contraceptive system: experience in Taiwan.

Subdermal Norplant-2 implantation, developed for contraception based on sustained release of levonorgestrel, has already been conducted in many countries around the world. From October 1986 to November 1988, a total of 267 female volunteers were enrolled in Norplant studies at the National Taiwan University Hospital. After a follow-up of 36 months, only one of the 231 evaluable cases (0.4%) became pregnant. The continuation rate was 84.5%, 61.3%, and 52.0% at the end of 12, 24 and 36 months after insertion, respectively. Menstrual problems were the most common adverse effects and were also the main reason for discontinuation. In the 23 patients who wished to become pregnant, fertility occurred soon after removal of the Norplant implant. After insertion, serum total cholesterol and triglyceride levels significantly decreased and the hemoglobin concentrations were increased. No liver or renal toxicities were detected. The data suggest that Norplant-2 is a highly effective, safe and long-acting method of reversible contraception. It would be worthwhile to introduce this contraceptive system into Taiwan's family planning program.

Adult↗
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↗