Biomedical subjects

S J Wu

Publications and source records attributed to S J Wu.

At least 19 recordsLinked to original sources

PubMed2006

Supercritical carbon dioxide extract exhibits enhanced antioxidant and anti-inflammatory activities of Physalis peruviana.

Physalis peruviana L. (PP) is a medicinal herb widely used in folk medicine. In this study, supercritical carbon dioxide (SFE-CO2) method was employed to obtain three different PP extracts, namely SCEPP-0, SCEPP-4 and SCEPP-5. The total flavonoid and phenol concentrations, as well as antioxidant and anti-inflammatory activities of these extracts were analyzed and compared with aqueous and ethanolic PP extracts. Among all the extracts tested, SCEPP-5 demonstrated the highest total flavonoid (234.63+/-9.61 mg/g) and phenol (90.80+/-2.21 mg/g) contents. At concentrations 0.1-30 microg/ml, SCEPP-5 also demonstrated the strongest superoxide anion scavenging activity and xanthine oxidase inhibitory effect. At 30 microg/ml, SCEPP-5 significantly prevented lipopolysaccharide (LPS; 1 microg/ml)-induced cell cytotoxicity in murine macrophage (Raw 264.7) cells. At 10-50 microg/ml, it also significantly inhibited LPS-induced NO release and PGE2 formation in a dose-dependent pattern. SCEPP-5 at 30 microg/ml remarkably blocked the LPS induction of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression. Taken together, these results suggest that SCEPP-5, an extract of SFE-CO2, displayed the strongest antioxidant and anti-inflammatory activities as compared to other extracts. Its protection against LPS-induced inflammation could be through the inhibition of iNOS and COX-2 expression.

Animals↗

PubMed2004

Investigation of the microstructure and mesotexture formed during thermomechanical controlled rolling in microalloyed steels.

Thermomechanical controlled rolling (TMCR) has been widely used as an effective method to improve the properties of steels. In the present paper, two commercial TMCR microalloyed steels were investigated. The grain size distributions and grain boundary misorientation angles were measured using electron backscattered diffraction patterns obtained using orientation imaging microscopy (OIM). The equivalent grain diameters were also measured using optical microscopy. Mixed coarse- and fine-grained regions were observed and the microhardness values were measured for both areas. Grain boundary misorientation angle distributions showed that the magnitude of mesotexture developed in the steel is dependent upon the rolling passes, the reduction ratio and the rolling temperatures including the finish rolling temperature. The surface layer, up to 2 mm depth, in Com-A steel had about 55% of grain boundaries with a misorientation angle below 12 degrees, much higher than in the central area ( approximately 30%), whereas Com-B steel showed similar distributions from the rolling surface to the centre. Misorientation results obtained from laboratory rolled steel plates with various TMCR procedures are also discussed as are OIM results from Charpy impact brittle fracture surfaces examining the effect of misorientation on crack propagation.

Alloys↗

PubMed2001

Different combinations of the heat-shock cognate protein 70 (hsc70) C-terminal functional groups are utilized to interact with distinct tetratricopeptide repeat-containing proteins.

A group of tetratricopeptide repeat (TPR)-containing proteins has been shown to interact with the C-terminal domain of the 70 kDa heat-shock cognate protein (hsc70). In the present study, the effect of the TPR-containing proteins, including the C-terminus of hsc70-interacting protein (CHIP), TPR1 and human glutamine-rich TPR-containing protein (hSGT), on refolding of luciferase by DnaJ and hsc70 was investigated. These proteins inhibited the restoration of luciferase activity by the chaperones. The inhibitory effect exerted by TPR1 and hSGT depended upon their binding to hsc70. However, the interaction with hsc70 did not appear to be required for the inhibition of luciferase refolding by CHIP. We also demonstrate that the peptide, GPTIEEVD, corresponding to the C-terminal end of hsc70, abolished the association of [(3)H]hsc70 with CHIP, TPR1 and hSGT. This implied that the GPTIEEVD motif of hsc70 was responsible for interacting with these TPR-containing proteins. However, the GGXP-repeats (where X is any aliphatic residue), another C-terminal conserved motif of vertebrate hsc70s, were not essential for interacting with the TPR-containing proteins. On the basis of mutagenesis studies, it was clear that a unique combination of the functional groups in the GPTIEEVD motif were utilized to interact with each TPR-containing protein, suggesting that inhibitors can be designed and used to elucidate the functional role of these interactions.

Amino Acid Motifs↗

PubMed2001

[A measure of chronic respiratory disease questionnaire for clinical trail].

OBJECTIVE: The aim of this paper was to investigate the reliability and validity of the Chronic respiratory disease questionnaire (CRQ) in China. METHOD: Sixty-eight patients with chronic respiratory disease who were in hospital from January to November, 1999 were surveyed with CRQ. Eighteen patients were investigated repeatedly with CRQ in one week to test the reliability; before and the 10th day after treatment, 50 patients were surveyed twice with CRQ and the peakflow of these patients were also detected. The same doctor explained questionnaires and tested peakflow. RESULTS: The correlated analysis of reliability was positive (r = 0.732, P < 0.01). The correlated analysis between the difference of twice-questionnaire scores and the difference of twice-peakflow value was also positive (r = 0.565, P < 0.01). CONCLUSION: CRQ can be used by the clinical doctors of China.

Adult↗

PubMed2001

The effect of mutating arginine-469 on the substrate binding and refolding activities of 70-kDa heat shock cognate protein.

On the basis of the X-ray structure of DnaK, we obtained an energy-minimized model for the C-terminal domain of rat 70-kDa heat shock cognate protein (hsc70). The model suggests that Arg-469 may play an important role in maintaining the substrate-bound conformation of hsc70. To verify this hypothesis, we substituted cysteine for Arg-469 and generated the hsc70(R469C) mutant. Compared to the wild-type hsc70, the mutant was more accessible to cleavage by endopeptidase Lys-C, implying that the overall structure of hsc70(R469C) is relatively loose. Moreover, hsc70(R469C) did not form tightly associated complexes with S-carboxymethyl-alpha-lactalbumin, an unfolded protein. The amount of heptapeptide FYQLALT bound to hsc70(R469C) was also decreased as determined by gel filtration. Thus, the affinity of hsc70(R469C) for polypeptide substrates is reduced. In the presence of DnaJ, the capability of hsc70(R469C) to refold the denatured luciferase was decreased by 50%. Therefore, for hsc70, reduction in affinity for substrates may affect its DnaJ-dependent refolding activity.

Animals↗

PubMed2001

Neutralizing monoclonal antibodies can potentiate IL-5 signaling.

IL-5 is a major determinant in the survival, differentiation and effector-functions of eosinophils. It mediates its effect upon binding and activation of a membrane bound receptor (R), composed of a ligand-specific alpha-chain and a beta-chain, shared with the receptors for IL-3 and granulocyte-macrophage colony-stimulating factor. We have generated and mapped the epitopes of three monoclonal antibodies (mAb) directed against this cytokine: the strong neutralizing mAb 5A5 and 1E1, and the very weak neutralizing mAb H30. We found that H30 as well as 5A5 can increase proliferation above the level induced by human (h)IL-5 alone, in a JAK-2-dependent manner, and at every sub-optimal hIL-5 concentration analyzed. This effect is dependent on mAb-mediated cross-linking of IL-5R complexes, and is only observed on cell lines expressing a hybrid human/mouse IL-5Ralpha-chain. We discuss these findings in view of the stoichiometric and topological requirements for an activated IL-5R. Since humanized anti-IL-5 mAb are currently in clinical testing, our findings imply that such mAb should be carefully evaluated for their potentiating effects.

Animals↗

PubMed2001

Tetrahydrobiopterin-deficient hyperphenylalaninemia in the Chinese.

BACKGROUND: Hyperphenylalaninemia (HPA) may be caused by either a deficiency in phenylalanine-4-hydroxylase or in tetrahydrobiopterin (BH4), the essential cofactor required for the hydroxylation of aromatic amino acids. The most common forms of BH4 deficiency are 6-pyruvoyl-tetrahydropterin synthase (PTPS) deficiency (MIM 261640) and dihydropteridine reductase (DHPR) deficiency (MIM 261630), which require a different treatment from classical HPA. RESULTS: Approximately 86% of BH4-deficient HPA in the Chinese population was found to be caused by PTPS deficiency. Eleven missense (73C-->G, 120T-->G, 155A-->G, 166G-->A, 200C-->T, 209T-->A, 226C-->T, 259C-->T, 286G-->A, 317C-->T, 430G-->C), one splicing (IVS3+1G-->A) and two deletion mutations (116-119delTGTT, 169-171delGTG) were identified in 37 unrelated PTPS-deficient Chinese families. Among these, 155A-->G, 259C-->T and 286G-->A mutation accounted for about 80% of the mutant alleles. The 155A-->G and 286G-->A mutations were found to be the common mutation in southern and northern Chinese, respectively. Only two Chinese DHPR-deficient families were detected among about 300 Chinese hyperphenylalaninemia cases. A single base transition 508G-->A on the DHPR cDNA was identified in two consanguineous DHPR-deficient siblings. A reduced level of DHPR mRNA expression was found in the other DHPR-deficient patient, which suggested that the mutation might lie in the regulatory region of the DHPR gene. CONCLUSIONS: The BH4-deficient HPA was estimated to make up around 30% of the Chinese population in Taiwan suffering from HPA, which is much higher than in Caucasian populations (1.5-2% of HPA).

5-Hydroxytryptophan↗

PubMed2001

A minimal transverse incision with low median sternotomy for pediatric congenital heart surgery.

OBJECTIVES: Median sternotomy is the incision of choice for most cardiac surgical procedures, but the full-length vertical skin incision generally leaves an unsightly scar. In certain patients undergoing short, low-risk procedures, cosmetic considerations are of relatively greater importance. METHODS: A minimal transverse curvilinear skin incision with low median sternotomy is described which gives adequate exposure for selected open-heart procedures. Since September 1997, this approach has been used in 22 pediatric patients undergoing open-heart surgery including five cases of Fallot's tetralogy. We also compared the operation time and result with other approaches. RESULTS: Using this modified method, the exposure of the heart was good enough, and there were no difficulties in cannulating the ascending aorta for cardiopulmonary bypass. Although it took a longer time to close the wound, the operation time was similar to the standard approach. The small transverse wound was not visible under conventional clothes. CONCLUSIONS: A minimal transverse incision with low median sternotomy provides an alternative approach for small wound open-heart surgery in patients with a simple congenital cardiac defect. It is technically feasible and has a good cosmetic result.

Adolescent↗

PubMed2001

Localization and characterization of acharan sulfate in the body of the giant African snail Achatina fulica.

Acharan sulfate is a glycosaminoglycan (GAG), having the structure -->4)-2-acetamido-2-deoxy-alpha-D-glucopyranose(1-->4)-2-sulfo-alpha-L-idopyranosyluronic acid (1-->, isolated from the body of the giant African snail Achatina fulica. This GAG represents 3-5% of the dry weight of this snail's soft body tissues. Frozen sections and polyester wax sections of the snail's body were stained by Alcian blue-periodic acid-Schiff's reagent (PAS) to localize acharan sulfate. Alcian blue staining indicated that GAG was mainly secreted into the outer surface of the body from internal granules. A highly mucous material was collected and treated and the acharan sulfate was recovered by ethanol and cetyl pyridinium chloride precipitation. Crude acharan sulfate was purified by DEAE-Sephacel ion-exchange chromatography. Depolymerization of intact mucus and purified acharan sulfate fractions by heparin lyase II (heparitinase I) from Flavobacterium heparinum produced an unsaturated disaccharide as a major product, establishing the repeating unit of acharan sulfate. These results demonstrate that mucus in the granule and secreted to the outside of the body is composed entirely of acharan sulfate.

Alcian Blue↗

PubMed2001

Human dendritic cells as targets of dengue virus infection.

Dengue virus infections are an emerging global threat. Severe dengue infection is manifested as dengue hemorrhagic fever and dengue shock syndrome, both of which can be fatal complications. Factors predisposing to complicated disease and pathogenesis of severe infections are discussed. Using immunohistochemistry, immunofluorescence, flow cytometry, and ELISA techniques, we studied the cellular targets of dengue virus infection, at both the clinical (in vivo) and the laboratory (in vitro) level. Resident skin dendritic cells are targets of dengue virus infection as demonstrated in a skin biopsy from a dengue vaccine recipient. We show that factors influencing infection of monocytes/macrophages and dendritic cells are different. Immature dendritic cells were found to be the cells most permissive for dengue infection and maybe early targets for infection. Immature dendritic cells exposed to dengue virus produce TNF-alpha protein. Some of these immature dendritic cells undergo TNF-alpha mediated maturation as a consequence of exposure to the dengue virus.

Biopsy↗

PubMed2001

Evaluation of hepatoprotective activity of legumes.

Mung bean, adzuki bean, black bean and rice bean are foods and folk medicines of Taiwan. We evaluated the effects of various water extract concentrations (100, 500 and 1000 mg/kg body wt.) and silymarin (25 mg/kg body wt. on acetaminophen-induced liver injury by measuring serum glutamate-oxalate-transaminase (sGOT) and serum glutamate-pyruvate-transaminase (sGPT) activities in rats. The results showed that the sGOT and the sGPT activities, increased by APAP, were decreased significantly (P < 0.05) through treatment with inceasing amounts up to 1000 mg/kg body wt. of the exracts. In particular, the mung bean aqueous extract showed the best hepatoprotective effect on APAP-induced hepatotoxicity. The pathological changes of liver injury caused by APAP improved by the treatment with all of the legume extracts, which were compared to silymarin as a standardized drug. In addition to these results, the extract of mung bean acted as a potential hepatoprotective agent in dietary supply.

Acetaminophen↗

PubMed2001

Ultrasound phased arrays for prostate treatment.

The effect of array geometry on the steering performance of ultrasound phased arrays is examined theoretically, in order to maximize array performance under the given anatomical constraints. This paper evaluates the performance of arrays with spherical and cylindrical geometry, determined by using computer simulations of the pressure fields produced at various extremes of steering. The spherical segment arrays were truncated for insertion into the rectum, and contained either annular or linear elements. The cylindrical arrays were either flat or had a variable curvature applied along their length. Fields were computed by dividing the array elements into many point sources. The effectiveness of an array configuration when steered to a particular focal location was assessed by defining a parameter, G, as the ratio of the intensity at the desired focus to the maximum intensity of any unwanted lobes. The performance of truncated spherical arrays with annular elements was evaluated for focal steering along the array axis (in depth, in the z direction). When steered 15 mm toward the source, these truncated spherical annular arrays exhibited excellent performance, with G>5.7 for arrays containing more than 10 elements. Similarly, the spherical arrays with linear elements performed well when steered along the array axis to the same degree, with G>7 (for element widths up to 3 lambda), though many more array elements were required. However, when these arrays were steered 15 mm laterally, along the length of the prostate (the y direction), the value for G fell below 1 for element widths greater than about 1.6 lambda. It was found that the cylindrical arrays performed much better for y-direction steering (G>4, for 60 mm arrays with an element width of 1.75 lambda), but their performance was poorer when steered in the z direction (G approximately 4 for an element width of 1.5 lambda). In order to find a compromise between these extremes, a curved cylindrical array was examined, which was a cylindrical array with additional curvature along its length. These curved cylindrical arrays yielded performance between that of spherical linear arrays and cylindrical arrays, with better steering along the y direction than the spherical arrays and better z-direction steering than the cylindrical arrays.

Humans↗

PubMed2001

Development and evaluation of serotype- and group-specific fluorogenic reverse transcriptase PCR (TaqMan) assays for dengue virus.

Five fluorogenic probe hydrolysis (TaqMan) reverse transcriptase PCR (RT-PCR) assays were developed for serotypes 1 to 4 and group-specific detection of dengue virus. Serotype- and group-specific oligonucleotide primers and fluorogenic probes were designed against conserved regions of the dengue virus genome. The RT-PCR assay is a rapid single-tube method consisting of a 30-min RT step linked to a 45-cycle PCR at 95 and 60 degrees C that generates a fluorogenic signal in positive samples. Assays were initially evaluated against cell culture-derived dengue stock viruses and then with 67 dengue viremic human sera received from Peru, Indonesia, and Taiwan. The TaqMan assays were compared to virus isolation using C6/36 cells followed by an immunofluorescence assay using serotype-specific monoclonal antibodies. Viral titers in sera were determined by plaque assay in Vero cells. The serotype-specific TaqMan RT-PCR assay detected 62 of 67 confirmed dengue virus-positive samples, for a sensitivity of 92.5%, while the group-specific assay detected 66 of 67 confirmed dengue virus-positive samples, for a sensitivity of 98.5%. The TaqMan RT-PCR assays have a specificity of 100% based on the serotype concordance of all assays compared to cell culture isolation and negative results obtained when 21 normal human sera and plasma samples were tested. Our results demonstrate that the dengue virus TaqMan RT-PCR assays may be utilized as rapid, sensitive, and specific screening and serotyping tools for epidemiological studies of dengue virus infections.

Animals↗

PubMed2001

Detection of dengue viral RNA using a nucleic acid sequence-based amplification assay.

Faster techniques are needed for the early diagnosis of dengue fever and dengue hemorrhagic fever during the acute viremic phase of infection. An isothermal nucleic acid sequence-based amplification (NASBA) assay was optimized to amplify viral RNA of all four dengue virus serotypes by a set of universal primers and to type the amplified products by serotype-specific capture probes. The NASBA assay involved the use of silica to extract viral nucleic acid, which was amplified without thermocycling. The amplified product was detected by a probe-hybridization method that utilized electrochemiluminescence. Using normal human plasma spiked with dengue viruses, the NASBA assay had a detection threshold of 1 to 10 PFU/ml. The sensitivity and specificity of the assay were determined by testing 67 dengue virus-positive and 21 dengue virus-negative human serum or plasma samples. The "gold standard" used for comparison and evaluation was the mosquito C6/36 cell culture assay followed by an immunofluorescent assay. Viral infectivity titers in test samples were also determined by a direct plaque assay in Vero cells. The NASBA assay was able to detect dengue viral RNA in the clinical samples at plaque titers below 25 PFU/ml (the detection limit of the plaque assay). Of the 67 samples found positive by the C6/36 assay, 66 were found positive by the NASBA assay, for a sensitivity of 98.5%. The NASBA assay had a specificity of 100% based on the negative test results for the 21 normal human serum or plasma samples. These results indicate that the NASBA assay is a promising assay for the early diagnosis of dengue infections.

Animals↗

PubMed2001

Molecular cloning and structural analysis of the gene encoding Bacillus cereus exochitinase Chi36.

The chi36 gene encoding exochitinase Chi36 was cloned from a Bacillus cereus 6E1 subgenomic library. The chi36 open reading frame is 1080 bp long encoding a Chi36 precursor protein of 360 amino acids, consisting of a 27 amino acid N-terminal signal peptide and a 333 amino acid sequence found in the mature Chi36 protein of 36.346 kDa. Chi36 shows significant amino acid sequence similarity to many bacterial chitinases, but has highest similarity to B. circulans WL-12 chitinase D. Chi36 belongs to subfamily B of bacterial chitinases in family 18 of glycosyl hydrolases. Chi36 shows a simple and compact structural organization composed of an N-terminal signal peptide and a C-terminal (beta/alpha)8-barrel catalytic domain (CaD). The Chi36 signal peptide is recognized by Escherichia coli, allowing Chi36 secretion. Chi36 is the first one-domain (CaD) bacterial chitinase cloned from B. cereus.

Journal Article↗

PubMed2001

Combined atrial and arterial switch operations for congenitally corrected transposition.

Conventional repair of congenitally corrected transposition of the great arteries (CCTGA) is directed at eliminating the associated defects and leaves the right ventricle in a systemic position. The long-term outcome of this procedure may involve deterioration of right ventricular function with tricuspid regurgitation and failure of the conduction system. We describe two consecutive patients with CCTGA, one of whom had apicocaval juxtaposition. The patients were aged 19 and 16 months, respectively, and both underwent a combination of atrial and arterial switch. These are the first two reported cases of successful completion of this type of operation in Taiwan. Our review of previously reported cases suggested that no significant difference exists in the outcome of patients with this condition who undergo either arterial switch or Rastelli-type repair plus atrial redirection. However, reported patients who underwent anatomic repair had lower early mortality, late mortality, and incidence of complete heart block than those who underwent conventional repair. The present two cases and our review of the literature suggest that, among patients with apicocaval juxtaposition, 1) Mustard operation is optimal for patients with small atrial volume; 2) one-and-one-half ventricular repair may be helpful to the outcome, especially when treatment is combined with Rastelli-type repair; and 3) excellent access to the ventricular septal defect through the tricuspid valve is afforded via a left atriotomy. From the present two cases and our review of the literature, we conclude that anatomic repair is superior to conventional repair of CCTGA in terms of protection against dysfunction and failure of the anatomic right ventricle, tricuspid valve, and conduction system. Long-term follow-up is mandatory.

Cardiac Surgical Procedures↗

PubMed2001

Modified arterial switch operation by sharing the common wall between the great arteries.

BACKGROUND: Suprapulmonary stenosis and coronary arterial obstruction still remain as problems after an arterial switch operation (ASO). We used a modified ASO applying the common wall and in situ transfer techniques to improve the current procedure. METHODS: From October 1996 to December 1997, 11 babies aged 6 days to 3 months with transposition of the great arteries underwent a modified ASO which included sharing the common wall between the great arteries until above the anterior neoaortic suture-line for coronary and pulmonary artery reconstruction. Coronary arteries were of usual type in three cases, juxtacommissural origin in five, and a high takeoff in one; all were redirected almost in situ. RESULTS: There was no early death (< 30 d), coronary or bleeding problems. One late death occurred after a repeat surgery for suprapulmonary stenosis. This was caused by upward stretching of the left pulmonary artery, which was placed above the high left-sided neoaortic anastomosis for in situ transfer of the high takeoff coronary arteries. Intraluminal growth of the adventitia also contributed to suprapulmonary stenosis, which decreased significantly when the common wall adventitia was cleaned in the last two cases we operated on. Ten patients were doing well at follow-up (30.9 +/- 5.2 mo). CONCLUSIONS: This modified ASO by common wall and in situ transfer might avoid coronary kinking and lessen the chance of postoperative bleeding. To avoid suprapulmonary stenosis, common wall adventitia inside the pulmonary pathway should be cleaned, and the left and right pulmonary arteries should also be kept in situ as possible as in coronary redirection.

Humans↗

PubMed2001

Valveless outflow reconstruction using autologous tissue as a posterior wall for pulmonary atresia with ventricular septal defect.

BACKGROUND AND PURPOSE: Reoperation is inevitable for some patients with pulmonary atresia who receive a heterograft or homograft in a primary Rastelli operation. Nonetheless, the need for reoperation in patients with classic Fallot's tetralogy who have undergone total correction with a transannular patch is unusual. We sought to change pulmonary atresia into Fallot's tetralogy and used a transannular patch instead of the conventional Rastelli operation. PATIENTS AND METHODS: Valveless outflow direct reconstruction was performed on 10 consecutive patients with pulmonary atresia and ventricular septal defect between August 1997 and 1999. Patient ages ranged from 1.3 to 11.5 years. A Blalock-Taussig shunt was previously constructed in four of these patients and a central shunt was constructed in five. The major aortopulmonary collateral arteries were occluded in one patient by repeated coil embolization after the central shunt. The strategy was to connect the right ventriculotomy with the pulmonary arteries directly, even if there was a gap with a long atretic cord. In patients with a previous central shunt covered with a Gore-Tex membrane, the reactive visceral pericardium over the in situ tissue (the left atrium, right ventricle, or aorta) was used as the autologous posterior wall. Thus, only autologous, fresh pericardium without a valve was used to cover the anterior part of the right ventricular outflow tract, as in the repair of classic Fallot's tetralogy with a transannular patch. RESULTS: There was no mortality, and the postoperative central venous pressure was low in all patients. No gradient was noted across the right ventricular outflow tract. Follow-up echocardiography revealed a competent tricuspid valve with mild pulmonary regurgitation in all patients. CONCLUSIONS: The results of this study suggest that valveless outflow direct reconstruction provides adequate pulmonary circulation without hypertension in pulmonary atresia patients with a ventricular septal defect if the tricuspid valve is competent.

Child, Preschool↗