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Biomedical subjects

C S Chang

Publications and source records attributed to C S Chang.

At least 163 records · Page 9Linked to original sources
PubMed1989

Unusual amino acid sequence of fasciatoxin, a weak reversibly acting neurotoxin in the venom of the banded krait, Bungarus fasciatus.

A weak reversibly acting neurotoxin, fasciatoxin, was found in the venom of Bungarus fasciatus. The sequencing was completed by manual and automated Edman analyses of the reduced and carboxymethylated protein and of the peptides obtained from enzyme digestions. It is composed of 63 amino acid residues with four disulphide bonds and a unique sequence at the C-terminal end. According to the criteria set by Ryden, Gabel & Eaker [(1973) Int. J. Pept. Protein Res. 5, 261-273], fasciatoxin lacks all of the five functionally invariant residues of neurotoxins. The hydropathy index indicates that fasciatoxin is devoid of a strong hydrophilicity domain for binding to the receptor site. Structural comparison with some typical neurotoxins also reveals the uniqueness of fasciatoxin in that the extent of similarity is only about 30%.

Amino Acid Sequence↗
PubMed1989

High prevalence of human papillomavirus infection and possible association with betel quid chewing and smoking in oral epidermoid carcinomas in Taiwan.

Seventeen oral epidermoid carcinomas, three oral papillomas, and 17 normal gingival tissues were tested for the presence of human papillomavirus (HPV) types 6, 11, 16, and 18 sequences by Southern blot hybridization. Episomal HPV-16 sequences in various amounts were detected in 76.4% of the oral carcinomas and in all three cases of papilloma. However, only one of the 17 normal tissues was HPV positive with an unknown type. None of the samples contained HPV-6, -11, or -18 sequences. Examination of the habits of the patients showed that 59% of the patients were betel quid chewers and 82% were smokers. Thus, the concurrent incidence of HPV infection and betal quid chewing and/or smoking habits in oral carcinoma patients observed in Taiwan is consistent with the view that both viral and chemical factors may be involved in the process of carcinogenesis.

Areca↗
PubMed1989

Amino acid sequence of a short chain neurotoxin from the venom of banded krait (Bungarus fasciatus).

The amino acid sequence of a short chain neurotoxin obtained from Bungarus fasciatus venom consists of 64 amino acid residues: Arg-Ile-Cys-Leu-Asn-Gln-Gln-Gln-Ser- Thr-Pro-Glu-Asp-Gln-Pro-Thr-Asn-Gly-Gln-Cys-Tyr-Ile-Lys-Thr-Asp-Cys-Gln- Asn-Lys - Thr-Trp-Asn-Thr-His-Arg-Gly-Ser-Arg-Thr-Asp-Arg-Gly-Cys-Gly-Cys-Pro-Lys- Val-Lys - Pro-Gly-Ile-Asn-Leu-Arg-Cys-Cys-Lys-Thr-Asp-Lys-Cys-Asn-Glu. The above result was obtained primarily from the amino acid analyses and sequencing of tryptic peptides accompanied with the necessary analyses and sequencing of the chymotryptic and lysyl endopeptidic peptides for alignment.

Amino Acid Sequence↗
PubMed1989

Amino acid sequence of a neutral phospholipase A2 (III) in the venom of Bungarus fasciatus.

Two phospholipases were found in the venom of Bungarus fasciatus, one in fraction III, the other in fraction X of the chromatographic separation. A neutral PLA2(III) purified from fraction III was subjected to amino acid sequencing by means of an automated sequenator applied to the intact RCM-PLA2 (III) and the individual peptides obtained from HPLC separation of the three types of enzymatic peptides. PLA(III) was shown to consist of 118 amino acid residues with 14 half-cystines. It is 65% homologous to the basic PLA2 obtained from fraction X.

Amino Acid Sequence↗
PubMed1989

Fusion proteins containing androgen receptor sequences and their use in the production of poly- and monoclonal anti-androgen receptor antibodies.

Complementary DNA segments that encode different domains of human and rat androgen receptors were fused to the Escherichia coli trpE gene using pATH expression vectors. Fusion proteins expressed by the bacteria were used to immunize rats and rabbits to obtain polyclonal antibodies to androgen receptors. Spleen cells of immunized rats were fused with myeloma cells to obtain stable hybridomas that produced monoclonal antibodies. Gradient centrifugation and immuno-precipitation assays indicated that the antibodies interacted with androgen receptors specifically.

Amino Acid Sequence↗
PubMed1989

Ludwig's angina: an analysis of 14 cases.

Ludwig's angina remains a potentially lethal disease entity as it causes rapidly progressive airway obstruction, although the current mortality rate is low. Early surgical intervention should be carried out in severe cases which show signs of fluctuation, abscess formation or other serious complications. We report our experience with 14 cases of Ludwig's angina, 12 of which (86%) were of dental origin. Only one case was complicated with Klebsiella pneumoniae septicemia which resolved upon treatment. There were no deaths. Surgical procedures including incision and drainage and tooth extraction were performed in 11 cases (78%). Antibiotics were administered to all patients. Most of them were treated with crystalline penicillin with or without an aminoglycoside. Only one patient received a tracheostomy in this series. The number of tracheostomies or intubations carried out was much lower than in previous reports. We suggest that an aggressive antimicrobial therapy, early surgical intervention and careful monitoring of the respiratory symptoms would reduce both the need for tracheostomy and the mortality rate.

Adult↗
PubMed1989

Variable regulation of sensitivity to retinoic acid-induced differentiation in wild-type and retinoic acid-resistant HL-60 cells.

The initial cell association and metabolic conversion of retinoic acid (RA) by HL-60 cells in serum-free, transferrin/insulin-supplemented, RPMI 1640 medium was greater than or equal to 10-fold greater than in RPMI 1640 medium containing 10% fetal bovine serum (FBS). This was paralleled under the serum-free conditions by 10-fold greater sensitivity to RA-induced differentiation, which was partially reversed by the addition of purified bovine serum albumin to the same concentration present in 10% FBS. In serum-free HL-1 medium, HL-60 cell sensitivity to RA-induced differentiation was approximately 250-fold less than in serum-free RPMI 1640 medium but, in this comparison, there was little difference in RA cell association or metabolism. A greater than 200-fold RA-resistant HL-60 subline had RA cell-association and metabolism rates similar to those of wild-type cells under all culture conditions. No significant qualitative differences in the high performance liquid chromatography elution patterns of polar metabolites were observed under any circumstances. These results indicate that inherent cellular properties, not associated with gross differences in RA uptake or metabolism, primarily determined the relative sensitivity or insensitivity of HL-60 cells to RA-induced differentiation but that RA responsiveness was markedly regulated by extracellular factors, one of which, serum albumin, appeared to act by decreasing the initial cell association and metabolism of RA, whereas other, as yet unidentified exogenous factors, may have acted independently of these functions.

Cell Differentiation↗
PubMed1989

[Histological study of hydroxylapatite mixed with collagen as osseous implant in mandible].

By using five Taiwan Macaca monkeys as experimental animals, three bony defects about 5 x 5 x 3 mm in size were created at each of their buccal region of mandible. Bovine skin collagen and particulate hydroxylapatite were used as implant materials. The artificial defects implanted with hydroxylapatite/collagen mixture were experimental group and the defects implanted with collagen or without any implantation were control groups. The monkeys were sacrificed at the time of 1,2,3,6,9 months after implantation surgery and were injected with tetracycline according to the above intervals at one week before being sacrificed. The specimens were divided into two parts, one of which was decalcified and stained with hemotoxylineeiosin for observation under optic light microscope, the other without decalcification was made into ground section for observation under fluorescent microscope. The result revealed that the healing processes of the two control groups were similar with each other. Bone formation was delayed in HA/Collagen group because it took almost five months to achieve complete bony repair of the mandibular defect. However bone formation at the HA/Collagen implant site was earlier than that at the pure HA implant site in our similar study. What's the role of collagen that played during bone formation still needed further investigation. The tissue response was good without obvious inflammatory cells infiltration. Clinical application of block form of dried HA/Collagen mixture was suggested for it was easier to handle and could decrease the flow of HA particles after implantation.

Animals↗
PubMed1989

Soluble interleukin-2 receptor levels in cerebrospinal fluid of patients with acute lymphocytic leukemia or with non-Hodgkin's lymphoma.

An elevated serum soluble interleukin-2 receptor (SIL-2R) has been noted in various hematological malignancies and conditions associated with active T-cell responses. Its appearance has also correlated with disease activity and tumor burden. Since few studies have been reported concerning SIL-2R in cerebrospinal fluid (CSF), work was undertaken to try to find if SIL-2R could be detected in the CSF of patients with acute lymphocytic leukemia (ALL) or non-Hodgkin's lymphoma (NHL), and whether it could become a clinical predictor of the central nervous system (CNS) involvement, and its response to therapy. Preliminary results showed that 1) the CSF SIL-2R is usually detectable in very low level with a mean of 15.1 +/- 14.2 units/ml compared with the mean serum level of 338.3 +/- 135.5 units/ml in eight normal controls; 2) there was no significant difference in the mean serum and CSF SIL-2R in five patients with ALL in a complete remission state compared with normal controls, while two ALL patients with CNS relapse and two NHL patients with CNS involvement had high levels of SIL-2R in CSF. High serum and low CSF SIL-2R levels were noted in another ALL case suffering from bone marrow relapse but without CNS relapse. It was also noted that decreased CSF SIL-2R concentration occurred subsequent to intrathecal chemotherapy in two ALL patients. From these results, we conclude that CSF SIL-2R might become a useful indicator of CNS involvement in patients with hematological malignancies and may predict response to chemotherapy.

Brain Neoplasms↗
PubMed1989

Circulating immune complexes in patients with hematologic diseases.

Circulating immune complexes (CIC) were measured by C1q-solid phase method in ninety-five patients with various hematologic diseases. The results showed significantly higher CIC levels in patients with acute myelocytic leukemia, chronic myelocytic leukemia, aplastic anemia and idiopathic thrombocytopenic purpura (ITP) than CIC levels in normal controls. However, there was no significant difference in such levels in patients with acute lymphocytic leukemia, non-Hodgkin's lymphoma and multiple myeloma when compared to normal controls. In this study, the level of CIC did not relate to prognosis for patients with non-Hodgkin's lymphoma. The findings demonstrated that a high level of CIC in patients with ITP usually responded poorly to steroid treatment. Other immunosuppressive agents were indicated in these cases. Therefore, the CIC level may serve as a therapeutic guide for the treatment of patients with ITP.

Antigen-Antibody Complex↗
PubMed1989

Nonparasitic hepatic cysts detected in ultrasonographic examination: analysis of 95 cases.

Ultrasonography has gained wide use in the diagnosis of hepatic cystic diseases. Ninety cases with nonparasitic hepatic cysts were detected in 4,615 patients who underwent routine abdominal ultrasonography. In this series, hepatic cysts were mostly discovered in men (62.1%), in the age range of 51-70 years (63.1%) and located in the right lobe of the liver (62.1%). Hepatomegaly, abdominal mass, abdominal pain, and jaundice were the common clinical manifestations in patients with symptomatic hepatic cysts (13.7%), especially in cases with larger or multiple cysts. Only 4 patients received invasive management; 2 with ultrasonographic guide aspiration alone, 1 with external drainage, and 1 with alcohol instillation. Complications in this series of liver cysts were noted in 3 patients (3.16%) including infection, portal hypertension and jaundice.

Adult↗
PubMed1989

[Hematological aspects of dengue fever].

Fifty patients with dengue fever from Sept. 1987 to Jan. 1988 were studied for hematological features. The lowest blood counts values throughout the course of illness were Hb: 13.2 +/- 1.9 gm/dl, WBC: (2.77 +/- 1.63) x 10(3)/mm3, Platelet: (8.7 +/- 5.5) x 10(4)/mm3. Leukopenia (WBC less than 4000/mm3) was present in 38 (76%) of the cases and thrombocytopenia (platelet less than 10 x 10(4)/mm3) in 27 (54%) of the cases. Leukocytes reached nadir (1000-2000/mm3) at the 5th-6th day after fever onset, thrombocytes reached nadir (2.0-5.0 x 10(4)/mm3) at the 5th-7th day after fever onset. Bone marrow studies showed mild hypocellularity in the acute stage (less than 1 week) and normal cellularity in the convalescent stage (greater than 1 week). Megakaryocytes increased with various stages of maturation of megakaryocytes appearing in a majority of patients. Nuclear vacuolization of megakaryocytes could also be found. Bone marrow CFU-GM when performed within one week of illness showed no growth or low colony count, and was nearly normal after one week of fever onset. This study may suggest that leukopenia in dengue fever may be caused by virus-induced destruction or inhibition of myeloid progenitor cells. Thrombocytopenia may result from by destruction of peripheral platelet or bone marrow megakaryocytes by viruses which consequently reduce the platelet production.

Adolescent↗
PubMed1988

Correction of the cDNA-derived protein sequence of prostatic spermine binding protein: pivotal role of tandem mass spectrometry in sequence analysis.

Spermine binding protein (SBP) is a rat ventral prostate protein that binds various polyamines, and the level of this protein and its mRNA is regulated by androgens. Previously, the cDNA for SBP was cloned and sequenced and an amino acid sequence deduced from the cDNA. Data from cloned and sequenced and an amino acid sequence deduced from the cDNA. Data from partial amino acid sequencing of the purified protein were consistent with the amino acid sequence deduced from the cDNA. However, the amino terminus of the protein was blocked, and therefore, direct protein sequence information confirming the cDNA reading frame of this region could not be obtained by Edman degradation. We have now employed an integrated approach using fast atom bombardment mass spectrometry, tandem mass spectrometry, and conventional sequencing methodologies to establish the amino-terminal sequence of the protein and to identify an amino acid sequence (35 residues) present in the purified protein but missing from the amino acid sequence deduced from cDNA clones for this protein. The missing piece of cDNA corresponds to an exon found in mouse genomic clones for a protein similar to rat SBP. Therefore, the cDNA clones for rat SBP may represent splicing variants that lack the sequence information of one exon. The blocked amino terminus of the protein was identified as 5-oxopyrrolidine-2-carboxylic acid. Mass spectrometry also provided evidence regarding glycosylation of the protein. The first of two potential glycosylation sites clearly carries carbohydrate; the second site is, at most, only partially glycosylated.

Amino Acid Sequence↗
PubMed1988

Molecular cloning of human and rat complementary DNA encoding androgen receptors.

Complementary DNAs (cDNAs) encoding androgen receptors were obtained from human testis and rat ventral prostate cDNA libraries. The amino acid sequence deduced from the nucleotide sequences of the cDNAs indicated the presence of a cysteine-rich DNA-binding domain that is highly conserved in all steroid receptors. The human cDNA was transcribed and the RNA product was translated in cell-free systems to yield a 76-kilodalton protein. The protein was immunoprecipitable by human autoimmune antibodies to the androgen receptor. The protein bound androgens specifically and with high affinity.

Amino Acid Sequence↗
PubMed1988

Structural analysis of complementary DNA and amino acid sequences of human and rat androgen receptors.

Structural analysis of cDNAs for human and rat androgen receptors (ARs) indicates that the amino-terminal regions of ARs are rich in oligo- and poly(amino acid) motifs as in some homeotic genes. The human AR has a long stretch of repeated glycines, whereas rat AR has a long stretch of glutamines. There is a considerable sequence similarity among ARs and the receptors for glucocorticoids, progestins, and mineralocorticoids within the steroid-binding domains. The cysteine-rich DNA-binding domains are well conserved. Translation of mRNA transcribed from AR cDNAs yielded 94- and 76-kDa proteins and smaller forms that bind to DNA and have high affinity toward androgens. These rat or human ARs were recognized by human autoantibodies to natural ARs. Molecular hybridization studies, using AR cDNAs as probes, indicated that the ventral prostate and other male accessory organs are rich in AR mRNA and that the production of AR mRNA in the target organs may be autoregulated by androgens.

Amino Acid Sequence↗
PubMed1988

Effect of metabolic or respiratory acidosis on rabbit renal medullary proton-ATPase.

Distal urinary acidification is thought to be mediated by an H+-ATPase sensitive to N-ethylmaleimide and dicyclohexyl-carbodiimide. We have studied the effect of chronic metabolic acidosis (NH4Cl for 3 days) or respiratory acidosis (inhalation of 10% CO2 for 2 days) on the H+-ATPase of plasma membranes prepared from the medulla. The enzymatic assay for the H+-ATPase was performed in the presence of ouabain and oligomycin and in the absence of Ca. H+-transport activity was assessed by the quenching of acridine orange in the presence of ATP. The 15-25% sucrose gradient fraction was enriched 40-fold in enzymatic activity over the homogenate, and 8-fold in enzymatic activity and 4-fold in H+-transport activity over the fluffy fraction (38,000 X g). Metabolic acidosis (pH less than 7.31) or chronic hypercapnia (PCO2 greater than 66 mmHg; 1 mmHg = 133.3 Pa) was induced for 2-3 days. Both groups showed the same enrichment factor in enzymatic and H+-transport assays as the control rabbits. Enzymatic and H+-transport activities, however, were not different between animals with respiratory acidosis and controls. Kinetic studies failed to disclose an increase in Vmax (673 vs. 702 mumol/(mg protein.min] or a decrease in Km (0.43 vs. 0.48 mM) in chronic hypercapnia as compared with controls. Metabolic acidosis also failed to increase H+-ATPase activity. These data demonstrate that the H+-ATPase of renal medulla does not display the expected increase in activity during acidosis. The role of this H+-ATPase in the adaptation to acidosis remains to be determined.

Acidosis↗