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Biomedical subjects

C H Chang

Publications and source records attributed to C H Chang.

At least 73 records · Page 4Linked to original sources
PubMed2001

Extra-articular deformity in distal radial fractures treated by external fixation.

OBJECTIVE: To determine the radiographic outcome in fractures of the distal radius treated with closed reduction and external fixation. DESIGN: A retrospective study. SETTING: The orthopedic department of National Taiwan University Hospital. PATIENTS: Eighty-five consecutive patients (36 female, 49 male), average age 48 years, with fractures of the distal radius seen between March 1995 and June 1998. INTERVENTIONS: Closed reduction and external fixation of fractures, followed up by good-quality posteroanterior and lateral radiographs to evaluate healing. MAIN OUTCOME MEASURES: Radial height, radial inclination and volar tilt were measured on radiographs obtained initially, immediately postoperatively and at the time of removal of external fixation. Data were analyzed by the t-test. RESULTS: Immediately after reduction and fixation, there was a significant improvement in the measurements of radial height and radial inclination. This improvement was gradually lost and height and inclination were significantly decreased at the time the external fixation device was removed. External fixation did not improve the volar tilt. CONCLUSION: External fixation is a popular method to improve the reduction of osseous deformity but cannot effectively protect comminuted distal radial fractures from loss of reduction, which may be associated with shortening and redisplacement.

Congenital Abnormalities↗
PubMed2001

Fibrillary glomerulonephritis.

The occurrence of fibrillary glomerulonephritis is unusual in Taiwan, whereas it occurs in approximately 1% of renal biopsy specimens taken in the United States of American. This disease is characterized by extracellular randomly arranged non-branching Congo red-negative microfibrils within glomeruli. The microfibrils are less than 30 nm in diameter, and electron microscopy is essential for diagnosis. Differential diagnosis of the deposition of extracellular non-branching microfibrils within glomeruli is important because discrete diseases have different therapeutic and prognostic implications. The report will discuss two cases of biopsy-proved fibrillary glomerulonephritis who presented with proteinuria, hematuria, renal insufficiency, and hypertension. It is noteworthy that the renal function persistently went downhill, even though the physician treated the patients with corticosteroids, pulse treatment and immunosuppressive agents.

Aged↗
PubMed2001

The Spanish National Institutes of Health-Chronic Prostatitis Symptom Index: translation and linguistic validation.

PURPOSE: The prominence of health related quality of life end points in international clinical research underscores the importance of well validated and translated measures to enable cross-cultural comparison. The National Institutes of Health (NIH)-Chronic Prostatitis Symptom Index (CPSI) assesses symptoms and health related quality of life in men with chronic nonbacterial, NIH type III prostatitis. To expand its use to Spanish speaking patients we performed a translation and linguistic validation. MATERIALS AND METHODS: The 9-item NIH-CPSI was translated into Spanish according to a standard methodology of 2 forward translations, 1 reconciled version, back translation of the reconciled version and 3 independent reviews by bilingual experts. The purpose of this methodology was to create a single universal Spanish version that would be acceptable to native Spanish speakers inside and outside of the United States. After the translation process the Spanish version was pre-tested in Argentina, Mexico, Spain and the United States. Patient responses were analyzed to identify necessary modifications. The internal consistency of the CPSI was evaluated using Cronbach's alpha. Pearson's product moment correlations were used to evaluate construct validity. RESULTS: Data were collected from chronic prostatitis patients, including 15 in Argentina, 15 in Mexico, 4 in the United States and 3 in Spain. The translation had high reliability overall and in all subscales (Cronbach's coefficient alpha = 0.81 to 0.94), and the subscales correlated well with each other (r = 0.76 to 0.97). However, patients expressed difficulty in distinguishing the response categories "a menudo" ("often") from "normalmente" ("usually") in question 3. We revised "a menudo" to "muchas veces" ("much of the time") and "normalmente" to "casi siempre" ("almost always") to improve the distinctiveness of response categories. CONCLUSIONS: The Spanish NIH-CPSI has high reliability as well as face and construct validity in Spanish speaking men from various countries. The Spanish NIH-CPSI permits cross-cultural comparisons of men with chronic nonbacterial prostatitis.

Adult↗
PubMed2001

Detecting unexpected variables in the MMPI 2 Social Introversion scale.

The standard scoring structure of the revised Minnesota Multiphasic Personality Inventory (MMPI-2) Social Introversion (Si) scale was reexamined with Rasch Measurement. The 69-item Si scale split into two distinct dimensions when their standardized residuals were factor analyzed. Items keyed "true" to Si defined one dimension and items keyed "false" defined another. Relationships between Lexile values (an index of reading difficulty and comprehension) and item difficulties were also explored. The article shows how to use Rasch Measurement to understand and improve personality assessment.

Adult↗
PubMed2000

Ets regulation of the erbB2 promoter.

Evaluating the chromatinized erbB2 gene in nuclei from breast cancer cells expressing varying levels of ErbB2 transcripts, we identified a nuclease-sensitive site within a 0.22 kb region of maximum enhancer activity centered over a conserved 28 bp polypurine(GGA)-polypyrimidine(TCC) mirror-repeat and an adjacent essential Ets binding site (EBS). Promoter footprinting with nuclear extracts reveals an intense Ets hypersensitivity site at the EBS whose degree of intensity correlates with the level of cellular ErbB2 expression. In vitro mapping assays show that the supercoiled erbB2 promoter forms an internal triplex structure (Hr-DNA) at the mirror-repeat element. Mutations preventing Hr-DNA formation can enhance erbB2 promoter activity in human breast cancer cells, a result consistent with previous demonstration that Ets-erbB2 promoter complexes cannot form when the mirror-repeat is engaged in triplex binding, and new results suggesting that Ets binding induces severe promoter bending that may restrict local triplex formation. In addition to previously described erbB2-regulating breast cancer Ets factors (PEA3, ESX/Elf-3), Elf-1 is now shown to be another endogenously expressed Ets candidate capable of binding to and upregulating the erbB2 promoter. Given current strategies to transcriptionally inhibit ErbB2 overexpression, including development of novel erbB2 promoter-targeted therapeutics, an EBS-targeted approach is presented using chimeric Ets proteins that strongly repress erbB2 promoter activity.

Adenocarcinoma↗
PubMed2000

Molecular cloning of a regulatory protein for membrane-bound guanylate cyclase GC-A.

Activation of membrane-bound guanylate cyclase GC-A by atrial natriuretic factor (ANF) may require the involvement of accessory proteins. To identify these postulated proteins, we isolated a 1. 0-kb cDNA clone from a rat brain expression library using a polyclonal antiserum against mastoparan. The 1.0-kb cDNA encodes a protein of 111 amino acids. Expression of this cDNA in COS-7 cells potentiated ANF-stimulated GC-A activity. Therefore, the 1.0-kb gene encodes a guanylate cyclase regulatory protein (GCRP). Fluorescence microscopy studies using the fusion protein of GCRP with green fluorescence protein (GFP) indicated that GCRP was present in the cytosol in PC12 cells, but translocated toward the plasma membrane in the presence of ANF. Coimmunoprecipitation experiments indicate that GCRP associates with GC-A in the presence of ANF. These results suggest that ANF induces the association of GCRP with GC-A and this association contributes to the activation of GC-A.

Amino Acid Sequence↗
PubMed2000

Estimating genotype relative risks in case-parental control studies: an optimal weighting approach.

The "case-parental control study" is a novel study design. It can quantify the relations between candidate genes and disease risk. Previous authors have proposed noniterative methods for estimating "genotype relative risks" (GRRs) in case-parental control studies. Here the authors propose yet another noniterative method. The new method is simple. It involves taking certain weighted averages with weights chosen according to one's educated guess about the likely values of the true GRRs. Monte Carlo simulation shows that the new estimators are approximately unbiased and that they have smaller variances than the previous estimators.

Adult↗
PubMed2000

MHC class II transactivator inhibits IL-4 gene transcription by competing with NF-AT to bind the coactivator CREB binding protein (CBP)/p300.

The MHC class II transactivator (CIITA) activates the expression of multiple genes involved in Ag presentation, but inhibits Th2-type cytokine production, including IL-4, during Th1 cell differentiation. Th1 cells derived from CIITA-deficient mice produce both Th1- and Th2-type cytokines, and the introduction of CIITA to Th2 cells down-regulates Th2-type cytokine gene transcription. Here we show that the IL-4 promoter is regulated by multiple protein-protein interactions among CIITA, NF-AT, and coactivator CBP/p300. The introduction of CBP/p300 and NF-AT enhances the IL-4 promoter activity, and this activation was repressed by CIITA. Furthermore, our data show that CIITA competes with NF-AT to bind CBP/p300 and that this competition dramatically influences transcriptional activation of the IL-4 promoter. We identified two domains of CIITA that interact with two distinct domains of CBP/p300 that are also recognized by NF-AT. CIITA mutants that retain the ability to interact with CBP/p300 are sufficient to inhibit NF-AT-mediated IL-4 gene expression.

Binding, Competitive↗
PubMed2000

Cloning, sequencing, heterologous expression, purification, and characterization of adenosylcobalamin-dependent D-lysine 5, 6-aminomutase from Clostridium sticklandii.

D-Lysine 5,6-aminomutase from Clostridium sticklandii catalyzes the 1,2-shift of the epsilon-amino group of D-lysine and reverse migration of C5(H). The two genes encoding 5,6-aminomutase have been cloned, sequenced, and expressed in Escherchia coli. They are adjacent on the Clostridial chromosome and encode polypeptides of 57. 3 and 29.2 kilodaltons. The predicted amino acid sequence includes a conserved base-off 5'-deoxyadenosylcobalamin binding motif and a 3-cysteine cluster in the small subunit, as well as a P-loop sequence in the large subunit. Activity of the recombinant enzyme exceeds that of the 5,6-aminomutase purified from C. sticklandii by 6-fold, presumably due to the absence of bound, inactive corrinoids in the recombinant enzyme. The K(m) values for adenosylcobalamin and pyridoxal 5'-phosphate are 6.6 and 1.0 microM, respectively. ATP does not have a regulatory effect on the recombinant protein. The rapid turnover associated inactivation reported for the enzyme purified from Clostridium is also seen with the recombinant form. Aminomutase activity does not depend on structural or catalytic metal ions. Electron paramagnetic resonance experiments with [(15)N-dimethylbenz-imidazole]adenosylcobalamin demonstrate base-off binding, consistent with other B(12)-dependent enzymes that break unactivated C-H bonds.

Adenosine Triphosphate↗
PubMed2000

Prenatal diagnosis of alobar holoprosencephaly by two-dimensional and three-dimensional ultrasound.

The aim of this study is to evaluate the sonographic characteristics of alobar holoprosencephaly (AH) in utero. Seventeen cases were diagnosed at 16-30 weeks' gestation by two-dimensional and three-dimensional ultrasound from October 1994 to December 1998. In this series, the prenatal prevalence was 1 out of 415 and the detection rate of AH by prenatal ultrasound was 100%. Eleven cases (64.7%) had concurrent facial anomalies. Cleft lip and hypotelorism were the most common associated facial anomalies (72.7%). Two cases (11.8%) were twin pregnancy with one fetus affected. We present one of the largest series in the literature and compare it with previous reports. From this series, we concluded that: (1) intracranial findings, including monoventricle, fused thalami, and the absence of midline structures, were reliable sonographic characteristics for prenatal diagnosis; (2) cleft lip and hypotelorism seemed to be more common associated facial malformations than cyclopia or cebocephaly with AH; and (3) although three-dimensional ultrasound did not change the diagnosis of AH made by two-dimensional ultrasound in this series, three-dimensional ultrasound does assist in defining the severity and extent of AH.

Adult↗
PubMed2000

Identification of an IFN-gamma responsive region in an intron of the invariant chain gene.

The mechanism by which IFN-gamma up-regulates invariant chain mRNA in antigen-presenting cells has been under intensive investigation. This study shows that in murine monocytic cells the transcriptional up-regulation mediated by the invariant chain (Ii) upstream enhancer only accounts for part of the induction of Ii mRNA by IFN-gamma. We have identified an intronic region in the murine Ii gene that contributes to the transcriptional up-regulation by IFN-gamma. The region has S (H), X/X2 and Y boxes similar to those in MHC class II promoters and the Ii upstream enhancer. Mutations at the putative S, X and Y boxes have abolished the ability of the region to mediate Ii up-regulation by IFN-gamma. Consistent with the functions of these boxes, our findings reveal that the up-regulation of Ii transcription by IFN-gamma mediated by the intronic region is dependent on the induction of class II transactivator by IFN-gamma.

Antigens, Differentiation, B-Lymphocyte↗
PubMed2000

An in vitro monitoring system for simulated thermal process in cryosurgery.

This paper describes a new in vitro experimental model that records temperature changes over a culture plate, which then can be used to assess the biological effects of cryosurgery. A cryoprobe and 16 thermocouples set up by a computer control system were used to monitor the temperature changes during freezing and thawing in a culture plate, and the data were used to create a temperature profile of the entire plate. Location of the thermocouples was confirmed by a digital camera viewing from under the plate, and temperature changes at any point in the interpolated areas were estimated using a curve fitting method. The estimated temperature was checked by sampling with four additional randomly placed thermocouples. Linear regression analysis showed that the estimated temperature and measured temperature were very close (correlation coefficients 0.98-0.99). MBT-2 tumor cells were cultured and then subjected to simulated cryosurgery. The surviving cells were stained with crystal violet and the cell death boundary was detected by image processing. Temperature history at the cell death boundary was retrieved and analyzed. With this system it is possible to recreate the temperature changes that result in a certain biological effect (such as cell death) during the process of simulated cryosurgery.

Animals↗
PubMed2000

Improvement of health outcomes after continued implementation of a clinical pathway for radical nephrectomy.

The clinical pathway is an important tool for outcome management. We evaluated the overall effects of the continued implementation of a clinical pathway for radical nephrectomy on the length of hospital stay, admission charges, and the quality of medical care. The data obtained from the second-year implementation (group 3) of the clinical pathway were compared with the data from the first-year implementation (group 2) and the year preceding implementation (group 1). Thirty-seven consecutive patients with renal cell carcinoma underwent radical nephrectomy in group 1, 47 in group 2, and 55 in group 3; all were enrolled in this study. The length of hospital stay, average admission charges, and 8 quality indicators were measured in these patients. We also evaluated the variances in the implementation of the clinical pathway. The mean length of stay decreased by 14.0% (P = 0.0048) in group 2, and by 15.8% (P= 0.0014) in group 3, when compared to group 1. The total admission charges significantly decreased by 19.0% (P = 0.001) in group 2, and by 27.9% (P < 0.0001) in group 3, compared to the charges for group 1. A continued decrease in charges for operation and anesthesia, laboratory, pharmacy, and others were found 2 years after implementation of the clinical pathway. Among the 8 quality indicators, 2 were continuously improved in the second-year implementation of the clinical pathway, 2 were improved significantly in the second-year implementation only, and 4 showed no significant change at all. Variances from the clinical pathway decreased significantly after continued implementation. Continued implementation of the clinical pathway for radical nephrectomy can improve a physician's practice continuously by decreasing the length of hospital stay, admission charges, and variances, and by improving quality. However, the improved results after implementation of the clinical pathway should be maintained carefully to assure good health care.

Adult↗
PubMed2000

Relapsing pancreatitis in a child duplication in an aberrant pancreatic lobe.

An aberrant pancreatic lobe associated with an enteric duplication cyst is a rare cause of relapsing pancreatitis in childhood. We present an 8-year-old boy with relapsing pancreatitis caused by this rare congenital foregut anomaly. The computed tomography (CT) findings revealed an unusually long segment of aberrant pancreatic lobe arising from the pancreatic neck, projecting anteriorly at a distance to a cystic duodenal duplication and appearing as an inflammatory mass. There has been no previous report of this unusual appearance on CT. Appreciation of the relevant anatomy provided by CT led to the successful management of this surgically-treatable cause of relapsing pancreatitis.

Acute Disease↗
PubMed2000

The effects of transcription and RNA processing on the initiation of chloroplast DNA replication in Chlamydomonas reinhardtii.

In Chlamydomonas reinhardtii, the origin for chloroplast DNA replication, Ori A, overlaps the coding region for the chloroplast ribosomal protein Rpl16. In an in vitro DNA replication system that uses cloned Ori A as template, alteration of transcription across rpl16 affects replication activity. S1 nuclease protection mapping of cellular RNA derived from this region revealed multiple 5' and 3' ends, and several 3' ends were mapped within mini Ori A (224 bp), the core region for replication initiation. We also demonstrated that the protein fraction used in the in vitro DNA replication system contained an RNA processing activity responsible for the generation of multiple 3' ends. The 3' ends of some of the processed RNA species coincided with those of the cellular transcripts. Initiation of DNA replication in the in vitro system changed the abundance of some of the processed RNA species, and the S1 nuclease protection pattern generated by the 3' ends now mimicked that of the in vivo transcripts. We also monitored the pattern of 3' ends in cellular transcripts from the rpl16 region during gametogenesis--when the chloroplast DNA is under-replicated--and detected a change in transcript abundance that correlated with that seen in the in vitro study. Measurements of the template activity of mutants with targeted sequences change near the sites of processing also supported the notion that the processed transcripts play an important role in DNA replication.

Animals↗
PubMed2000

Evaluating factors that influence hand-arm stress while operating an electric screwdriver.

The objective of this study is to evaluate the factors contributing toward hand-arm stress while operating an electric screwdriver. Hand-arm stress was investigated in terms of individual finger force exertion, flexor digitorum EMG, and hand-transmitted vibration. Two activation modes (push and push plus trigger (P + T)), two preset shut-off torque levels (low and high) and three horizontal operating distances (far, middle, and near) were evaluated. Thirteen healthy male subjects drove screws into a horizontally mounted iron plate with pre-tapped screw holes using an in-line electric screwdriver in randomly ordered experimental combinations. The results indicate that using push-to-start mode at low torque level was better than the other combinations of activation mode x torque because it resulted in less hand-arm stress. In addition, the far distance level (33-45 cm away from the work table edge) caused greater stress than the middle and near distances, and hence is best avoided. While operating an in-line electrical screwdriver, the force contribution of the small finger was greatest, followed by the ring finger. The average force contributions of the index, middle, ring, and small fingers were 19, 25, 27, and 30%, respectively, while operating with push-to-start mode.

Adult↗
PubMed2000

Anticonvulsive and free radical scavenging activities of vanillyl alcohol in ferric chloride-induced epileptic seizures in Sprague-Dawley rats.

Vanillyl alcohol (VA) is a component of Gastrodia elata Bl. (GE), which is a traditional Chinese herb widely used to treat convulsive disorders or dizziness. This study examined the role of VA in the anticonvulsive properties of GE in a Sprague-Dawley rat model of epilepsy. The anticonvulsive and free radical scavenging activities of VA were examined after intracortical injection of ferric chloride (100 mM, 8 microl) to induce epileptic seizures. These seizures were verified by behavioral observations and electroencephalographic (EEG) and electromyographic (EMG) recordings. Ferric chloride injection resulted in increased lipid peroxide levels in the ipsilateral and contralateral cerebral cortex, and increased luminol-chemiluminescence (CL) and lucigenin-CL counts in the peripheral blood. Intraperitoneal injection (i.p.) of VA (200 mg/kg or 100 mg/kg) or phenytoin 10 mg/kg prior to ferric chloride administration significantly inhibited wet dog shakes (WDS) and lipid peroxide levels in the bilateral cerebral cortex. VA 200 mg/kg also significantly reduced luminol-CL and lucigenin-CL counts in the peripheral blood, but no significant effect was observed following administration of VA 100 mg/kg or phenytoin. These data indicate that VA has both anticonvulsive and suppressive effects on seizures and lipid peroxidation induced by ferric chloride in rats. Data from the present study also demonstrate that VA has free radical scavenging activities, which may be responsible for its anticonvulsive propertics. This finding is consistent with the results from previous studies that generation of superoxide radical evoked by injection of iron salt into rat brain plays a critical role in ferric chloride-induced seizures. In addition, the results of the present study suggest that the anticonvulsive effect of GE may be attributable, at least in part, to its VA component.

Acridines↗