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Biomedical subjects

C Y Chang

Publications and source records attributed to C Y Chang.

At least 127 records · Page 7Linked to original sources
PubMed1999

Lack of association between deletion polymorphism of the ACE gene and ischemic vascular diseases in a Chinese population in Taiwan.

BACKGROUND: The association between deletion/insertion polymorphism of the angiotensin I-converting enzyme (ACE) gene and ischemic vascular diseases (IVDs) is still unclear. This study was designed to evaluate the role of ACE gene polymorphism in the pathogenesis of IVDs in a Chinese population living in Taiwan. METHODS: A case-control study was carried out to examine the association of the ACE gene genotype and the allele frequency in 400 IVD patients, including 214 patients with ischemic cerebrovascular disease (ICVD) and 186 patients with ischemic heart disease (IHD), compared with 200 control individuals. RESULTS: Although the patients with ICVD and IHD were found to have higher frequencies of the D/D genotype (22% and 43%) and the D allele (20% and 42%) than the controls (16% and 39%), the statistical differences were not significant, as shown by chi 2 analysis (p > 0.05). Upon further comparison of the frequencies of the D allele among the two sexes and different age subgroups, there was still no significant association. CONCLUSIONS: Deletion polymorphism of the ACE gene was not associated with IVD in a Chinese population in Taiwan. The unique or synergistic effect of other genes that might contribute to the pathogenesis of IVDs needs further investigation.

Aged↗
PubMed1999

Management of facial nerve injury due to temporal bone trauma.

OBJECTIVE: This article provides an overview of relevant data regarding the management of facial nerve injury due to temporal bone trauma. DATA SOURCES: Sources used were relevant English language clinical and basic science publications. STUDY SELECTION: A Medline search dating back to 1966 for articles concerning temporal bone trauma and facial nerve injury including both human and animal data was performed. Articles were included if they contained relevant data or were significant reviews on the subject. A retrograde bibliography search was then conducted to acquire any articles that may have been missed by the computerized search, including those papers published prior to 1966. DATA EXTRACTION: The data from each paper were reviewed individually. DATA SYNTHESIS: The data were not amenable to formal meta-analysis or valid data summarization. CONCLUSIONS: Patients who should not require surgical intervention include those who have: documented normal facial nerve function after injury regardless of progression, presentation with incomplete facial nerve paralysis with no progression to complete paralysis, and degeneration <95% on ENoG. The remaining patients presumably have a poorer prognosis for return of facial nerve function although it remains unclear exactly how poor the return of function will be. Decompression surgery likely has a beneficial effect if performed within 14 days of injury, so those patients with expected poor natural outcomes may be offered this intervention. Late decompression surgery is not recommended. Late exploratory surgery is recommended only in those patients who do not experience adequate recovery of facial nerve function and likely require nerve repair. Despite the availability of a relatively large volume of published data, there remain many unanswered questions.

Algorithms↗
PubMed1998

Studies on segmented polyetherurethane for biomedical application: effects of composition and hard-segment content on biocompatibility.

Segmented polyetherurethane (SPEU) materials based on polytetramethylene oxide (PTMO, Mw 1000 and 2000) with various hard-segment contents were synthesized and their biocompatibilities studied via different tests. The static contact angle data reveal that the higher hard-segment-content SPEU material possesses a lower contact angle, implying that the surface of the higher hard-segment-content SPEU is more hydrophilic than its low hard-segment-content SPEU counterpart. The catalyst- and additive-free PTMO-based SPEU materials in this study possess neither a hemolytic nor a cytotoxic response that could be considered non toxic for biomedical applications. By using L-929 cell lines, a cell-seeding test indicated that the higher hard-segment-content SPEU material possesses quicker cell attachment and proliferation behaviors. In vitro platelet adhesion tests indicated that the lower hard-segment-content SPEU possesses less platelet adhesion than the high hard-segment-content SPEU material. Both ex vivo canine artery-artery (A-A) and arterio-venous (A-V) shunting tests revealed that the extent of platelet adhesion reaction is less for lower hard-segment content SPEU. In addition, the blood compatibility of SPEU material synthesized from PTMO 1000 excels over PTMO 2000 SPEU material by near the same levels as the hard-segment-content SPEU.

Animals↗
PubMed1998

Zinc uptake into fibroblasts is inhibited by probenecid.

Cellular zinc transport has not been fully characterized. The role of an anion carrier was investigated by treating normal human fibroblasts, and those carrying a mutation which affects zinc transport, acrodermatitis enteropathica (AE), with the anion carrier inhibitor, probenecid. Zinc uptake (2, 10, or 20 micromol 1(-1) 65zinc) was determined during initial rates of uptake (15 min) following treatment with 0, 10 or 20 mmol 1(-1) probenecid. Probenecid stimulated extracellular zinc binding in normal and AE fibroblasts. Probenecid inhibited the internalization of zinc in normal, but not AE, fibroblasts. Normal fibroblasts exhibited an apparent Km which was reduced by 53% and 44% in the 10 and 20 mmol 1(-1) probenecid treated cells. The Vmax was also reduced in the normal fibroblasts by 51% and 50% in the 10 and 20 mmol 1(-1) probenecid treated cells. The results suggest that a probenecid-sensitive anion carrier is involved in the internalization of zinc in human fibroblasts. The lack of an effect of probenecid on the internalization of zinc in the AE fibroblasts suggests that the mutation involves a probenecid-sensitive anion transport system, and that there may be a secondary mechanism for zinc transport in these cells.

Acrodermatitis↗
PubMed1998

Application of the surface rendering technique of three-dimensional ultrasound in prenatal diagnosis and counselling of Klippel-Trenaunay-Weber syndrome.

Klippel Trenaunay-Weber syndrome is a complex developmental disorder characterized by a triad of cutaneous haemangioma, varicosities of the body, and unilateral limb hypertrophy. We describe the prenatal diagnosis of Klippel-Trenaunay-Weber syndrome at 15 weeks' gestation using the surface rendering technique of three-dimensional ultrasound. The vivid three-dimensional images of the affected fetus are invaluable in prenatal diagnosis and parental counselling.

Adult↗
PubMed1998

Giant ossified cavernous hemangioma of an extremity associated with an equinovarus deformity.

A 39-year-old woman suffered from swelling and tenderness of the right leg for 31 years. Imaging studies showed a large soft tissue lesion on the right side extending from the proximal portion of the thigh to the ankle. She underwent several operations due to the leg mass and associated equinovarus deformity of the right ankle. The pathologic findings were those of an ossified cavernous hemangioma. This appears to be one of the largest hemangiomas to be reported. It revealed the three types of calcification characteristic of hemangiomas. Equinovarus deformity of the ankle caused by contracture of the calf in this case was probably related to repeated bleeding.

Adult↗
PubMed1998

Pictorial review: Radiological diagnosis of duodenal abnormalities.

This article depicts the radiological findings of many common gastrointestinal entities. Specifically, examples of disease processes that affect the stomach, gall bladder, small intestine, pancreas and colon are shown. In most cases there is correlation between ultrasound, computed tomography (CT) and fluoroscopic imaging. The major emphasis of the article, however, is to demonstrate classic barium imaging of a large number of gastrointestinal disease processes.

Barium Sulfate↗
PubMed1998

Isolation and characterization of tilapia (Oreochromis mossambicus) insulin-like growth factors gene and proximal promoter region.

To understand the molecular mechanism which controls the transcription of the insulin-like growth factors (IGFs) gene, we have cloned and sequenced the cDNA for the proximal promoter region of the tilapia IGFs gene and have characterized its activity by chloramphenicol acetyltransferase (CAT) transient transfected expression assays. Tilapia (Oreochromis mossambicus) IGF-I cDNA (549 bp) was amplified by PCR from single-stranded cDNA of growth hormone (GH)-induced liver RNA using a pair of oligonucleotides specific for fish IGF-I as amplification primers. Tilapia IGF-I and IGF-II 5' termini were analyzed by rapid amplification of cDNA 5' ends (5'RACE). Analysis of the 5'RACE results revealed two transcription start sites in IGF-I and one transcription start site in IGF-II. Different fragments of the 5' flanking region were transfected into human lung adenocarcinoma cells. In the cell line, maximum promoter activity was located in the distal 657 basepairs of the IGF-I 5' flanking region and in the distal 450 basepairs of the IGF-II 5' flanking region. The in vivo actions of the IGFs promoter on developmental stage expression were investigated further in transgenic zebrafish in which an IGFs promoter-driven green fluorescent protein (GFP) encoding the cDNA transgene was microinjected into embryos. Morphologic and RT-PCR studies of the transgenic zebrafish indicated that IGF-I promoter-driven GFP transcripts appeared for the first time in the 1-K-cell stage and the IGF-II promoter-driven GFP transcripts appeared for the first time in the 32-cell stage. Fluorescent (GFP) distribution was apparent within 48 h in IGF-II-transgenic zebrafish embryos, especially in eye, muscle, corpuscle, floor plate, horizontal myoseptum, yolk sac extension, and yolk sac. These results indicate that the IGF-I and IGF-II promoters are active in tissue and in a development-specific manner. Our findings also indicate that the IGF-II promoter influences the growth of fish embryos earlier than does IGF-I, and IGF-II has higher levels of expression than does IGF-I. These results suggest that the IGF-II promoter plays a growth factor role in teleost embryo development.

Amino Acid Sequence↗
PubMed1998

Effect of mild acid treatment on the survival, enteropathogenicity, and protein production in vibrio parahaemolyticus.

Vibrio parahaemolyticus is an important food-borne enteropathogen that encounters various adverse conditions in its native environment or during infection. Effects of mild acid treatment on survival under stress conditions, enteropathogenicity, and protein production in this pathogen were investigated. Logarithmically grown cells, at pH 7.5 shifted to pH 5.0 for 30 min, were more resistant to subsequent acid challenge at pH 4.4. A two-phase adaptive procedure (pH 5.8 for 30 min; pH 5.0 for 30 min) was better than a single-phase procedure for enhancing the acid tolerance of this pathogen. The acid-adapted cells were cross-protected against the challenges of low salinity and thermal inactivation. One-dimensional polyacrylamide gel electrophoresis revealed that proteins with molecular masses of 6.4, 9.0, 13.6, 16.3, 18.9, 22.9, 24.4, 28.3, 33. 9, 36.9, 41.2, 47.6, 58.1, 65.6, 80.5, 88.2, and 96.9 kDa were induced or significantly enhanced, while proteins of 25.3, 30.1, 30. 7, and 91.7 kDa were significantly inhibited. Two-dimensional polyacrylamide gel electrophoresis revealed that 20 species of proteins were induced or significantly enhanced, while 26 species were inhibited. In assays conducted using the suckling mouse model, enteropathogenicity of the acid-adapted cells was significantly enhanced in terms of intestine/body weight ratio and in vivo recovery of infected cells.

Adaptation, Physiological↗
PubMed1998

Constitutive activation of the aromatic hydrocarbon receptor.

The ligand-activated aromatic hydrocarbon receptor (AHR) dimerizes with the AHR nuclear translocator (ARNT) to form a functional complex that transactivates expression of the cytochrome P-450 CYP1A1 gene and other genes in the dioxin-inducible [Ah] gene battery. Previous work from this laboratory has shown that the activity of the CYP1A1 enzyme negatively regulates this process. To study the relationship between CYP1A1 activity and Ah receptor activation we used CYP1A1-deficient mouse hepatoma c37 cells and CYP1A1- and AHR-deficient African green monkey kidney CV-1 cells. Using gel mobility shift and luciferase reporter gene expression assays, we found that c37 cells that had not been exposed to exogenous Ah receptor ligands already contained transcriptionally active AHR-ARNT complexes, a finding that we also observed in wild-type Hepa-1 cells treated with Ellipticine, a CYP1A1 inhibitor. In CV-1 cells, transient expression of AHR and ARNT leads to high levels of AHR-ARNT-dependent luciferase gene expression even in the absence of an agonist. Using a green fluorescent protein-tagged AHR, we showed that elevated reporter gene expression correlates with constitutive nuclear localization of the AHR. Transcriptional activation of the luciferase reporter gene observed in CV-1 cells is significantly decreased by (i) expression of a functional CYP1A1 enzyme, (ii) competition with chimeric or truncated AHR proteins containing the AHR ligand-binding domain, and (iii) treatment with the AHR antagonist alpha-naphthoflavone. These results suggest that a CYP1A1 substrate, which accumulates in cells lacking CYP1A1 enzymatic activity, is an AHR ligand responsible for endogenous activation of the Ah receptor.

Animals↗
PubMed1998

Lipoblastomatosis of the shoulder: unusual MR appearance.

Lipoblastomatosis is a rare benign lipomatous tumour of childhood and infancy, classically showing high signal identical to fat on T1 weighted images. A case of histologically proven lipoblastomatosis in an infant is presented, in which MRI showed low signal on T1 weighted images identical to that of muscle instead of high signal. This appearance has not been previously reported.

Female↗
PubMed1998

Aromatic hydrocarbon receptor polymorphism: development of new methods to correlate genotype with phenotype.

Differential CYP1A1 inducibility, reflecting variations in aromatic hydrocarbon receptor (AHR) affinity among inbred mouse strains, is an important determinant of environmental toxicity. We took advantage of the Ahr polymorphism in C57BL/6 and DBA/2 mice to develop an oligonucleotide-hybridization screening approach for the rapid identification of DNA sequence differences between Ahr alleles. Oligonucleotides containing single-base changes at polymorphic sites were immobilized on a solid support and hybridized with C57BL/6 or DBA/2 AHR cDNA radiolabeled probes. The observed hybridization patterns demonstrate that this approach can be used to detect nucleotide differences in the Ahr coding region with very high accuracy. In parallel experiments, we used a yeast two-hybrid system to assess phenotypic differences in AHR function. AHR activation, as measured by beta-galactosidase reporter activity in Saccharomyces cerevisiae strain SFY526, was determined following treatment with varying doses of the AHR ligand beta-naphthoflavone (BNF). We found that the C57BL/6 AHR has about a 15-fold higher affinity for BNF than the DBA/2 AHR, in much better agreement with results reported for whole-animal studies than the values observed by in vitro ligand-binding assays. Using C57BL/6 and DBA/2 AHR chimeric proteins, we also confirmed the previously reported observation that an A375V change is principally responsible for the high- to low-affinity AHR phenotype. There has been no straightforward method to reliably and reproducibly phenotype large numbers of humans for CYP1A1 inducibility or AHR affinity. Screening human AHR cDNAs by oligonucleotide-hybridization and yeast two-hybrid methodologies will be invaluable for the rapid and unequivocal determination of changes in DNA sequence and receptor-ligand affinities associated with human AHR polymorphisms.

Animals↗
PubMed1998

Plasma levels of antioxidant vitamins, selenium, total sulfhydryl groups and oxidative products in ischemic-stroke patients as compared to matched controls in Taiwan.

The possible involvement of oxidative damage and antioxidant protection has been suggested in the pathogenesis of stroke which is the second-leading cause of death in Taiwan. In this study we investigated the relationship between ischemic stroke and plasma status of antioxidants and oxidative products. Plasma levels of vitamin A, alpha-tocopherol, carotenoids, selenium (Se), total SH groups (T-SH), thiobarbituric acid-reactive substances (TBARS) and protein carbonyl, a marker of protein damage, were determined in ischemic-stroke patients (n = 36, blood sampled within 24 hrs after the clinical event) in comparison with 21 matched controls. The cholesterol-adjusted carotenoids and vitamin E were significantly lower (P < 0.05) in the plasma of ischemic-stroke patients than those of the controls. TBARS were higher (P < 0.05) in the patients than in the controls but Se, T-SH and protein carbonyls were not significantly different between the two groups. Separation of the patients into small-artery ischemic stroke (SAIS, n = 17) and large-artery ischemic stroke (LAIS, n = 19) groups revealed that both carotenoids/cholesterol and vitamin E/cholesterol ratios were significantly lower in both LAIS and SAIS groups than the controls (n = 21) while vitamin A/cholesterol was not different among the three groups. TBARS were only significantly higher in the LAIS group. The results demonstrated that, within 24 hrs after the clinical event, the acute-ischemic stroke patients had lowered levels of cholesterol-adjusted carotenoids and alpha-tocopherol but elevated levels of TBARS in the plasma as compared to the matched controls. It remains to be resolved as to whether enhanced lipid peroxidation is a cause or a result of lowered antioxidants in ischemic stroke.

Adult↗
PubMed1998

Triangular fibrocartilage of wrist: presentation on high resolution ultrasonography.

This study consisted of two parts. Part I is for detection of the normal triangular fibrocartilage by high resolution ultrasonography and Part II is a preliminary study to evaluate high resolution ultrasonography in the diagnosis of tears of the triangular fibrocartilage. Normally, the triangular fibrocartilage was seen in all cases in Part I as an inverse triangular structure of homogeneous hyperechogenicity on transverse and oblique sagittal scans at the level of the distal radioulnar joint. At its waist it measured from 2.3 to 4.2 mm (mean, 3.0 +/- 0.5 mm) on oblique sagittal scan and from 2.5 to 3.7 mm (mean, 3.2 +/- 0.4 mm) on transverse scan. Under normal conditions, the triangular fibrocartilage is thicker than 2.5 mm on both transverse and oblique sagittal sections with a confidence level of 95%. In Part II, eight of the 47 wrists were found to be hypoechoic in the triangular fibrocartilage region, which proved to be tears by arthrography. Six cases showed a homogeneous hyperchoic triangular fibrocartilage measuring from 1.8 to 2.8 mm (mean, 2.3 +/- 0.5 mm) in transverse section and from 0 to 2.2 mm (mean 1.2 +/- 1.1 mm) in oblique sagittal section; five of these proved to be tears by arthrography. In contrast, 33 wrists had a homogeneous hyperechoic triangular fibrocartilage measuring from 2.5 to 4 mm (mean, 3.1 +/- 0.4 mm) and 2.5 to 4.2 mm (mean, 3.1 +/- 0.6 mm) on transverse and oblique sagittal sections, respectively; 27 proved to be normal triangular fibrocartilage by arthrography. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 68.4%, 96.4%, 92.9%, 81.8%, and 85.1%, respectively. HRUS can display the normal triangular fibrocartilage as a homogeneous hyperechoic and inverted triangular structure. The torn triangular fibrocartilage appears as a hypoechoic region or as thinning (< 2.5 mm) of the hyperechoic structure on either transverse or oblique sagittal section. HRUS has an acceptable accuracy in the diagnosis of triangular fibrocartilage tear.

Adolescent↗