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Biomedical subjects

C Y Chang

Publications and source records attributed to C Y Chang.

At least 145 records · Page 8Linked to original sources
PubMed1998

Cubital tunnel syndrome: diagnosis by high-resolution ultrasonography.

The purpose of this study was to evaluate the morphologic changes in the ulnar nerve in cubital tunnel syndrome with high-resolution ultrasonography. The mean values of the short axis (cm) x long axis (cm) at the arm, epicondyle, and forearm levels were 0.057 +/- 0.01, 0.068 +/- 0.019, and 0.062 +/- 0.01 in control group; 0.069 +/- 0.04, 0.139 +/- 0.06, and 0.066 +/- 0.023 in the symptomatic side in patients with cubital tunnel syndrome; and 0.063 +/- 0.029, 0.068 +/- 0.029, and 0.057 +/- 0.012 in the normal side in patients with cubital tunnel syndrome. No significant difference was found in the area (short axis x long axis) of the ulnar nerve at the arm, epicondyle and forearm levels between the left and right ulnar nerve in the control group and between the control group and the normal side in symptomatic patients. However, the mean value of the area of the ulnar nerve at the epicondyle level in symptomatic patients was significantly larger than that of the control group and that of the contralateral side in patients, and the P value was less than 0.001. High resolution ultrasonography can detect morphologic changes in the ulnar nerve accurately, and it could therefore be useful as a screening and even follow-up modality in patients with cubital tunnel syndrome.

Adult↗
PubMed1998

High resolution computed tomography of temporal bone fracture.

BACKGROUND: High resolution computed tomography (HRCT) is highly efficient in demonstrating the anatomy of the temporal bone. This study evaluates its application to temporal bone fractures (TBF). METHODS: We collected data from 26 cases of TBF in the past two years. All cases underwent HRCT examination. The clinical information was reviewed and correlated with the imaging findings. RESULTS: Eighty-six percent of the cases had longitudinal fractures. Axial scans were the most useful in identifying the fracture line. Mastoid opacification on routine head computed tomography (CT) was also useful in indicating possible TBFs. Complications of TBF, such as ossicular chain disruption, facial nerve damage or otorhino-liquorrhea, were identified clearly using HRCT. CONCLUSIONS: To minimize or prevent the sequelae of TBF, accurate radiologic evaluation is necessary as soon as possible after injury. HRCT of the temporal bone delineates the bony and soft tissue anatomy with high accuracy and we recommend it as the diagnostic modality of choice.

Adolescent↗
PubMed1998

The lambda holin accumulates beyond the lethal triggering concentration under hyperexpression conditions.

Most bacteriophages terminate infection by creating lesions in the cytoplasmic membrane, which not only cause immediate cell death but also allow escape of a phage-encoded endolysin. Destruction of the peptidoglycan and cell lysis follows very rapidly, allowing efficient release of the progeny virions. These membrane lesions are formed by a small integral membrane protein called a holin. Holins have highly charged carboxyl-termini that are thought to have two transmembrane alpha-helical domains. Holins are believed to oligomerize and form large holes in the inner membrane. The prototype holin is the S protein from bacteriophage lambda. Scheduling of the lytic event is determined in part by the "structure directed initiation" or sdi translational control region. Inductions of S, cloned under a variety of native and nonnative promoters but with native translational control, resulted in cell lysis at about 1000 molecules of holin per cell, and thus do not produce biochemically useful amounts of S protein. By utilizing a plasmid-based system with the T7 RNA polymerase promoter in tandem with a consensus ribosome binding site, Coomassie blue-detectable quantities of S protein were obtained upon induction, corresponding to an approximately 100-fold increase over the normal lethal level of holin. Characterization of this expression system is presented and discussed with respect to the current model of holin function.

Amino Acid Sequence↗
PubMed1998

Triangular fibrocartilage perforations with bilateral negative ulnar variant wrists: a case report.

Triangular fibrocartilage (TFC) constitutes the major part in the triangular fibrocartilage complex, which stabilizes the distal radioulnar joint and functions as a cushion for axial compression forces. Tears in the TFC are often encountered with positive ulnar variance and regarded as part of a degenerative process of the ulnocarpal joint. They are occasionally seen as the result of trauma and are less likely to be found in a young population, especially in those who are in the first two decades of life, without causative traumatic injury. We report the case of a 12-year-old boy with bilateral negative ulnar variances with incidental findings of TFC tears in both wrists. This is a rare case, as he had no history of a traumatic event.

Cartilage, Articular↗
PubMed1997

Cloning of porcine neuron growth inhibitory factor (metallothionein III) cDNA and expression of the gene in Saccharomyces cerevisiae.

Growth inhibitory factor (GIF), a member of the metallothionein (MT) family, is also known as MTIII. This protein distinguishes itself from other MT isoforms by exerting an inhibitory effect on cortical neuron growth instead of metal ion buffering. In this work, we cloned MTIII genes from a porcine brain cDNA library. Two species of clones were isolated that vary with respect to one nt in the coding sequence. This discrepancy results in the translation of two MTIII primary structures having a different amino acid at residue 46. Herein, both MTIII cDNAs were constructed into an expression vector and transformed into yeast cells, respectively. The yeast carrying either MTIII gene displayed a similar metal tolerance when cultured in a medium containing metal. The resistance to metal toxicity was attributed to the expression of MTIII gene which was confirmed by RNA and protein analyses. The characteristics of the protein stability, metal binding affinity and ultraviolet absorption spectrum of the yeast produced MTIII are also compared with those of MTII. The comparison reveals that both MTs have similar physical characteristics. Moreover, circular dichroism spectrum of Cd saturated MTIII was analyzed as well. Typical Cys-Cd bands for MTII appear in the spectrum, indicating similar metal-thiol interactions for MTIII to those for other MT isoforms.

Alzheimer Disease↗
PubMed1997

Molecular, biological, and preliminary structural analysis of recombinant bryodin 1, a ribosome-inactivating protein from the plant Bryonia dioica.

Bryonia dioica (Cucurbitaceae family) produces at least two type I ribosome-inactivating proteins, bryodin 1 (BD1) and bryodin 2 (BD2). A cDNA sequence encoding BD1 was isolated from B. dioica leaf mRNA using degenerative oligonucleotides and codes for a 22 amino acid signal peptide followed by a protein of 267 residues. Expression of two recombinant BD1 (rBD1) forms in Escherichia coli yielded proteins of 267 (to the natural stop codon) and 247 amino acids (to the putative cleavage site yielding the mature protein) that had identical protein synthesis inhibition activity as compared to native BD1. The substitution of Lys for Glu at position 189 near the active site reduced the ability of rBD1 to inhibit protein synthesis by 10-fold. Toxicologic analysis showed that rBD1 was well tolerated in rodents with LD50 values of 40 mg/kg in mice and >25 mg/kg in rats. A crystal of mature rBD1 protein was used to collect X-ray diffraction data to 2.1 A resolution. The rBD1 crystal structure was solved and showed extensive homology with other type I RIPs and A chains of type II RIPs. The studies described here demonstrate that rBD1 retains full biologic activity and serve as a guide for using this potent, yet nontoxic, RIP in the construction of single-chain immunotoxin fusion proteins.

Amino Acid Sequence↗
PubMed1997

Heterogeneity of antigen expression and lectin labeling on microglial cells in the olfactory bulb of adult rats.

Microglia in different layers of the rat olfactory bulb expressed a variety of membrane antigens except for CD4 (OX-35). Bulb microglial cells bearing complement receptor type 3 (OX-42) were ubiquitous and their immunoreactivity varied considerably in different bulb layers. Although very few in number, labeled microglia in all layers also expressed major histocompatibility complex class I antigen (OX-18), leukocyte common antigen (OX-1) and unknown macrophage antigen (ED-2). The latter was localized in cells distributed almost exclusively in the perivascular spaces. The immunoreactivity of ED-1, an unknown cytoplasmic or lysosomal membrane antigen in macrophages, was localized in labeled microglia which were concentrated mainly in the granule cell layer and periglomerular zone of the bulb. A variable number of microglial cells were stained with OX-6 (major histocompatibility complex class II antigen) and they were located predominantly in the periglomerular zone and at the junction between the granule cell layer and the subependymal layer. Ultrastructural study using GSA I-B4 lectin labeling showed that microglia in different layers of the bulb exhibited similar labeling patterns in their subcellular structures. A remarkable feature was the occurrence of some microglia in the olfactory nerve layer, subependymal layer and granule cell layer adjacent to the subependymal layer in which the cells showed intense lectin labeling at their Golgi apparatus, a feature which was absent in microglia of other bulb layers. Present results showed the regional differences in microglial antigen expressions and lectin labeling within the olfactory bulb. It is therefore suggested that the cells subserve very different specific functions depending on their ambient microenvironments. The heterogeneity of microglial functions in the olfactory bulb may be related to the progressive regeneration and degeneration of its containing neurons.

Animals↗
PubMed1997

Production of biologically active recombinant tilapia insulin-like growth factor-II polypeptides in Escherichia coli cells and characterization of the genomic structure of the coding region.

Insulin-like growth factor-II (IGF-II) is a fetal growth factor in humans, but has not been clearly identified in fish up to now. For a detailed understanding of the physiological response of fish IGF-II, the first step was to clone tilapia IGF-II cDNA from the brain cDNA library, coding the region of genomic DNA, and also expressing tilapia IGF-II polypeptides from Escherichia coli. Tilapia cDNA sequences total 1,977 bp, and predicted nucleotide sequences and amino acid sequences of tilapia share 77.9% and 90.7% homology identity with rainbow trout IGF-II, respectively. The genomic structure of the tilapia prepro-IGF-II coding region is very difficult to sequence in mammals and birds. The cloned tilapia IGF-II gene coding region appears much more complex than in other vertebrates. In tilapia IGF-II, the first coding exon I encoding part of the signal peptide sequence is 25 amino acids shorter than the first coding exon of mammals and birds. The other 23 amino acids of the signal peptide, and the first amino acids of the B domain and C domain are encoded by tilapia coding exon 2. The C, A, and D domains, and the first 20 amino acids of the E peptide are encoded by tilapia coding exon 3. The other E peptides and the 3' untranslated region (UTR) region are encoded by tilapia coding exon 4. These data show that the IGF-II genes have significantly differing structures in vertebrate evolution, and there are differences of interrupting introns in the IGF-I genomic structure compared with mammals. To obtain recombinant biologically active polypeptides, tilapia IGF-II B-C-A-D domains were amplified using the polymerase chain reaction (PCR), then ligated with glutathione S-transferase (GST, pGEX-2T vector). Tilapia recombinant IGF-II protein was purified and characterized in E. coli. The fusion protein was also digested with thrombin and appeared as a recombinant IGF-II polypeptide single band with a molecular mass of 7 kD. The recombinant tilapia IGF-II protein biological function was measured by stimulation of [3H]thymidine incorporation. The assay concentration was set up from 0 to 120 nM to stimulate tilapia ovary cell line (TO-2) significantly to uptake thymidine. The results suggest that the recombinant IGF-II protein was dose dependent.

Amino Acid Sequence↗
PubMed1997

Evaluation of tibial cortical bone by ultrasound velocity in oriental females.

In order to evaluate the feasibility of detecting bone status by measuring cortical ultrasound velocity, ultrasonic transmission velocity of the anterior cortex of shin was measured on 175 normal Chinese females aged 31-75 years (mean 52.3 +/- SD 9.1 years). The data were compared with bone mineral density (BMD) of the lumbar spine and/or hip measured by dual energy X-ray absorptiometry (DXA), which was performed on the same day as speed of sound (SOS) examination. Comparison was made with SOS of Caucasian women previously reported in the literature. SOS of three volunteers measured by two different operators were also enrolled in our study for precision testing. The mean value of SOS of the 175 females was 3850.7 +/- 119.3 m s-1 (range: 3411.7-4220.5 m s-1), the peak value being in the fourth decade. The rate of decrease of transmission velocity per decade from fourth decade to fifth decade was 1.7%, while that of fifth decade to sixth decade was 2.2% and that of sixth decade to seventh decade was 4.0%. The interoperative and intraoperative coefficient variance with and without reposition were under 0.32%. SOS moderately correlated with BMD at different sites, the best correlation being with the lumbar spine anteroposterior projection (r = 0.509; p < 0.0001, Pearson's test). There were significant differences in SOS between pre- and post-menopausal groups (p = 0.01, ANOVA test), and between peri- and post-menopausal groups (p = 0.02), but there was no correlation of body weight and height with SOS. SOS also inversely correlated with age and post-menopausal duration. The mean value of SOS in our study was similar to that of Caucasians, but the rate of decrease over 50 years of age was faster. The rate of decline of tibial cortical SOS was similar to that of trabecular bone as previously reported in the literature. As there is a significant decrease of SOS in older females, and older Oriental females suffer from an accelerated cortical bone loss, it is concluded that cortical bone SOS may be a useful method for detecting potential osteoporotic patients in this ethnic group.

Absorptiometry, Photon↗
PubMed1997

[The establishment of the digital imaging analysis system on the lower maxillofacial soft tissue]

Soft tissue shape is an important parameter to evaluate the postprosthetic effect of facial profile.In this study,the technique of digital imaging analysis was used to transferring from imaging informations to digital information,and then these information were imputed to computer for capturing,measuring and analyzing.So far,a set of digital imaging analysis system relating to the speciality of prosthodontics has been established preliminarily,with the advantage of quantitative analysis,non invasion and accuracy.It will provide a new way for reconstructing vertical dimension of occlusion.

Journal Article↗
PubMed1997

[Analysis of the measurement on of the maxillofacial soft tissue's parameters association with vertical dimension]

The rehabilitation of vertical dimension of occlusion(VDO) exactly is one of the most important procedure for dental prosthesis in the field of prosthodontics.In this study,total of 19 subjects with normal range occlusion were selected.We measured 33 parameters relating to VDO of their facial soft tissue at intercusping position,with the technique of digital imaging analysis.The results as follows:we established a set of normal values of facial soft tissue parameters,which is suitable for the age group of 21-24 years old.It would provide an objective criterion for the rehabilitation of VDO.Also the normal values in this studies had been compared with other other studies,and it showed that the values of some parameters in our study,such as CH-CH',nasolabial angle were very close to oter data.Furthermore,it was found that both the position of the upper lip and the lower lip of the subjects were more anterior to that of white men,while the degrees of nasolabial and labiomental convexity were less obvious.

Journal Article↗
PubMed1997

[Computer-aided analysis of maxillofacial soft tissue simulating with vertical dimensions of 4 different types]

In this study,33 parameters relating to vertical dimension of occlusion(VDO) of 19 subjects' maxilofacial soft tissue of four different vertical dimentsions(VDs) were measured.All of them were in intercusping position,with the technique of digital imaging analysis.The findings as follows:(1)A set of normal values of facial soft tissue's parameters of four different VDs was established,which was suitable for the age group of 21-24 years old.(2)When the VD was raised to the certain height(H4),it would affect the size of angle of the inferior soft tissue of lip distinctly,furthermore,the correlation analysis showed that there was a positive correlation between the variance of VDs would arouse the change of the inferior soft tissues of lip,especially its size of angle,is very correspondingly and obviously.

Journal Article↗
PubMed1997

[Chemical burn caused by hydrofluoric acid in Kaohsiung area--a 5-year experience].

Hydrofluoric acid (HF) has been used extensively in industry and laboratory, and also is a common agent for occupational chemical burn. Severe pain and destruction of deep tissue layers occurred when skin was injured by hydrofluoric acid. Some fatal change may happen especially when hydrocalcemia was induced. For presentation of its special character and the use of antidote, we report one outbreak and six individual victims of hydrofluoric acid injury during the previous 5 years in Kaohsiung area. We hope medical personnel could have more accurate management and clinical care for those who are injured by HF, and workers should pay attention to any chemical agents they use to prevent any further injury as a result of careless use of such chemicals.

Adult↗
PubMed1997

Genetic localization of the type I trimethoprim resistance gene and its dissemination in urinary tract isolates in Taiwan.

In a total of 425 urinary isolates of E. coli, Enterobacter spp., and Klebsiella spp. selected, there were 169 (45.4%) isolates harbouring type I dihydrofolate reductase (DHFR) gene among 374 trimethoprim-resistant isolates. In these 169 isolates, only 17.2% hybridized with the Tn7 probe. According to another probe specific for the integrase gene of integron, 87.6% showed a positive reaction. Further analysis by restriction mapping proved that the type I DHFR gene was inserted into a integron-like structure. These results indicate that the type I DHFR gene that was initially observed in association with transposable element Tn7 is becoming associated with an integrase function similar to integrons in most instances. Further analysis of the distribution of Tn21-like integrase gene in clinical isolates indicated that the prevalence rates were 86.4%, 84.8%, and 76.7% respectively in E. coli, Enterobacter spp., and Klebsiella spp.. Furthermore, the integrase gene found in our clinical isolates proved to be mediated by a plasmid, demonstrated by Southern hybridization. Thus, the trimethoprim-resistant gene that developed under selective pressure from the double drug trimethoprim and sulphonamide was transmitted by insertion into integron-like structure and then mediated by plasmid transfer for dissemination.

Animals↗
PubMed1997

Measuring tibial cortical bone status by ultrasonic velocity.

BACKGROUND: Post-menopausal osteoporosis has become a serious public health problem with the increase of the geriatric population. Dual energy x-ray absorptiometry (DEXA) is the most common method for diagnosis of osteoporosis by quantitative change of bone, but recently there is increasing interest in measuring both qualitative and quantitative changes of bone by ultrasound. This study measured ultrasound velocity of anterior tibial cortex to evaluate the feasibility of detecting cortical bone status by speed of sound (SOS). METHODS: SOS in anterior tibial cortex was measured on 205 females referred from clinicians for routine bone mineral density (BMD) measurement. These females were divided into 2 groups. Group 1 consisted of 170 females aged from 30 to 75 years (mean: 55.2 +/- 9.3 years), who never received estrogen therapy. Group 2 consisted of 35 females in the post-menopausal status aged ranged from 45 to 69 years (mean: 51.5 +/- 3.5 years), who had received estrogen gel or oral estrogen tablet (0.625 mg/day) replacement therapy for prevention of postmenopausal osteoporosis for a period of 6 to 68 months (mean: 25.3 +/- 2.3 months). For precision test, 3 volunteers whose SOS was measured by 2 different operators were also enrolled in our study. BMD by DEXA of L-spine and/or hip was also performed on the same day of SOS examination. We analyzed the precision of this new method, calculated mean value of SOS to see if there was any difference with respect to pre- at, and post-menopausal status between estrogen users and nonusers by SOS, and tried to find the relationship of SOS with body habitus and BMD. RESULTS: Mean value of SOS of group 1 females was 3852 +/- 150.3 m/s, with peak value in the fourth decade. There were inverse correlation of SOS with age (r = -0.36, p < 0.0005) and the period after menopause (r = -0.32, p < 0.0005). The decreasing rate of SOS per decade from 31 to 50 years of age was 1.7%, while that of 51 to 70 years was 4.3% in group 1 females. With regard to menopausal status, there was significant difference of SOS between pre- and post-menopausal females (p = 0.01, ANOVA test), between at and post-menopausal females (p = 0.02). Significant difference (p < 0.05, ANOVA test) between group 2 estrogen users and group 1 postmenopausal nonusers was also noted. There was no evidence of correlation of body weight or height with SOS. Both inter- and intra-operator precision of SOS was under or equal to 0.32%. Moderately correlation between SOS and BMD was noted. CONCLUSIONS: Our study demonstrated good precision in SOS measurement of tibial cortical status. It was inversely correlated with age and post-menopausal period; it also significantly discriminated estrogen users from nonusers, and pre-, at from post-menopausal subgroups. However, for further evaluation of the relationship between SOS and the most severe complication of osteoporosis, i.e. osteoporotic fracture, population-based long-term followup is still required.

Adult↗
PubMed1996

X-ray structure of the uncomplexed anti-tumor antibody BR96 and comparison with its antigen-bound form.

The X-ray structure of the uncomplexed human chimeric Fab' of the anti-tumor antibody BR96 has been determined at 2.6 A resolution. The structure has been compared with Lewis Y antigen-complexed structures of BR96 which were determined previously. The comparison reveals segmental motions and/or conformational rearrangements of three CDR loops (L1, L3, and H2), whereas CDR H3 does not undergo changes upon complexation despite its significant main-chain contacts to the carbohydrate antigen. In light of the uncomplexed chimeric Fab' structure reported here, the previously observed high mobility of the CL:CH1 domains of the complexed chimeric BR96 Fab is rationalized as a "swinging" motion approximately about the axis of the elbow bend.

Animals↗
PubMed1996

Crystallization and preliminary crystallographic analysis of E. coli uridine 5'-diphospho-N-acetylenolpyruvylglucosamine reductase in two new crystal forms.

Uridine 5'-diphospho-N-acetylenolpyruvylglucosamine reductase (MurB), the second enzyme in the peptidoglycan synthetic pathway of Escherichia coli, has been crystallized in two previously unreported forms, one orthorhombic and the other monoclinic. MurB (molecular mass 38 kDa) crystallizes in a range of conditions that utilize polyethylene glycol fractions as precipitants, and crystals can be grown with or without the enzyme's substrate, uridine 5'-diphospho-N-acetylenolpyruvylglucosamine. X-ray diffraction from crystals of the orthorhombic form extends to 2 A resolution and shows the symmetry and systematic absences of space group P2(1)2(1)2(1). These crystals show significant variations in cell dimensions at room temperature and at 100 K. A crystal used to collect a 2.0 A resolution data set at a synchrotron source showed cell dimensions at ca 100 K of a = 51.0, b = 79.3 and c = 87.1 A, indicating one molecule peroasymmetric unit. The monoclinic crystals scatter X-rays to 3.0 A resolution consistent with space group P2(1), unit-cell dimensions (ca 100 K) a = 50.7, b = 92.4, c = 85.5 A, and beta = 104 degrees, and two molecules per asymmetric unit. Mercury derivatives have been prepared with both orthorhombic and monoclinic forms, and efforts are underway to exploit these derivatives to determine the structure of this protein.

Journal Article↗