Search PubMed⌕ Search

Biomedical subjects

K H Wang

Publications and source records attributed to K H Wang.

At least 19 recordsLinked to original sources
PubMed2002

Voiding dysfunction following TVT procedure.

The aim of the study was to assess the incidence of abnormal voiding in patients who had undergone tension-free vaginal tape (TVT) placement. Women who had undergone a TVT sling procedure for stress or mixed incontinence more than 3 months previously reported their voiding habits (frequency, urgency, nocturia, urinary stream quality and incontinence) over the previous 3 days. A pelvic examination and ultrasound postvoid residual (PVR) were performed. Normal voiding was classified as a PVR <100 ml, frequency of six or fewer voids per day and two or fewer per night, and a urinary stream considered normal by the patient. Subjects were classified as either 'normal' (group 1) or 'abnormal' (group 2) voiders. Demographic factors, pre-operative urodynamic testing and concomitant surgical procedures were compared between groups. From September 1999 to November 2000, 59 women underwent a TVT procedure. Two were excluded from analysis [cervical malignancy (1), interstitial cystitis (1)]. There were no healing abnormalities and no patients displayed a positive empty bladder stress test. Forty-two (74%) women were included in group 1 and 15 (26%) in group 2. Urinary continence was reported by 49 (86%): 93% in group 1 and 67% in group 2. Factors highly correlated with postoperative voiding dysfunction included abnormal preoperative uroflow pattern and configuration (P = 0.007), preoperative low peak flow rate <15 ml/s (P = 0.049), preoperative vault prolapse or enterocele (P = 0.001), concurrent vault suspension surgery (P = 0.03) and postoperative urinary tract infection (UTI) (P = 0.0006). Preoperative urinary retention (postvoid residual >100 ml) or detrusor instability, age and body mass index differences were not statistically significant. Multivariate analysis revealed that preoperative abnormal uroflow and postoperative UTI were related to group 2 (P = 0.02). Our conclusions were that the TVT sling procedure has success and voiding dysfunction rates similar to those of other proven anti-incontinence procedures. Various factors were shown to be associated with postoperative voiding difficulties. Tension-free placement of the tape may not prevent the development of post-operative voiding dysfunction.

Aged↗
PubMed2001

Diversity and specificity of actions of Slit2 proteolytic fragments in axon guidance.

The Slits are secreted proteins that bind to Robo receptors and play a role in axon guidance and neuronal migration. In vertebrates, Slit2 is a major chemorepellent for developing axons and is involved in the control of midline crossing. In vivo, Slit2 is cleaved into 140 kDa N-terminal (Slit2-N) and 55-60 kDa C-terminal (Slit2-C) fragments, although the uncleaved/full-length form can also be isolated from brain extract. We explored the functional activities of Slit2 fragments by engineering mutant and truncated versions of Slit2 representing the N-, C-, and full/uncleavable (Slit2-U) fragments. Only Slit2-N and Slit2-U bind the Robo proteins. We found that in collagen gel, olfactory bulb (OB) but not dorsal root ganglia (DRG) axons are repelled by Slit2-N and Slit2-U. Moreover, only Slit2-N membranes or purified protein-induced OB growth cones collapse. Finally, we found that only recombinant Slit2-N could induce branching of DRG axons and that this effect was antagonized by Slit2-U. Therefore, different axons have distinct responses to Slit2 fragments, and these proteins have different growth-promoting capacities.

Alkaline Phosphatase↗
PubMed2001

Functional annotation of a full-length mouse cDNA collection.

The RIKEN Mouse Gene Encyclopaedia Project, a systematic approach to determining the full coding potential of the mouse genome, involves collection and sequencing of full-length complementary DNAs and physical mapping of the corresponding genes to the mouse genome. We organized an international functional annotation meeting (FANTOM) to annotate the first 21,076 cDNAs to be analysed in this project. Here we describe the first RIKEN clone collection, which is one of the largest described for any organism. Analysis of these cDNAs extends known gene families and identifies new ones.

Animals↗
PubMed2001

The organic precursors affecting the formation of disinfection by-products with chlorine dioxide.

The object of this research was to study the formation of disinfection by-products by using chlorine dioxide (ClO2) as a disinfectant reacting with different properties of organic substance in natural aquatic environment. The adsorbent resin (XAD-4, XAD-7) was used to divide the organic matters in raw water into three groups. The influence of the function groups on structure, reaction tendency, and formation of disinfection by-products generated by the reaction of these organic substances with chlorine dioxide was explored. The experimental results show that the three different organic groups formed using adsorbent resin were hydrophobic substance, hydrophilic acid, and non-acid hydrophilics in proportions of 43%, 41%, and 16%, respectively. Within the raw water in our study, the hydrophilic substance had a higher distribution proportion than that described in general articles and journals, which indicates that this water was contaminated with pollution from human beings. The exploration of the reactivity of the three different organic substances with chlorine dioxide shows that the unit consumption of disinfection agent per unit organic matters (represented by ClO2/DOC) is in the following sequence hydrophobic substance > hydrophilic substance > non-acid hydrophilics. It indicated that larger molecular organic precursors had larger consumption of disinfectant. We also discovered that after the reaction of the three different organic substances with chlorine dioxide, the largest amount of disinfection by-products were generated by the non-acid hydrophilics.

Adsorption↗
PubMed2000

The formation of disinfection by-products in water treated with chlorine dioxide.

In this study, chlorine dioxide (ClO(2)) was used as an alternative disinfection agent with humic acid as the organic precursor in a natural aquatic environment. The major topics in this investigation consisted of the disinfection efficiency of ClO(2), the formation of disinfection by-products (DBPs), and the operating conditions. The results indicated that the pH value (pH 5-9) did not affect the efficiency of disinfection while the concentration of organic precursors did. The primary DBPs formed were trihalomethanes (THMs) and haloacetic acids (HAAs). The distribution of the individual species was a function of the bromide content. The higher the ClO(2) dosage, the lower the amount of DBPs produced. The amount of DBPs increased with reaction time, with chlorite ions as the primary inorganic by-product.

Chlorine Compounds↗
PubMed2000

Diagnosis of Penaeus monodon-type baculovirus by PCR and by ELISA of occlusion bodies.

The black tiger prawn Penaeus monodon is a valuable aquaculture product in Taiwan. Two specific diagnostic methods were established for P. monodon-type baculovirus, one using polymerase chain reaction (PCR) technology and the other enzyme-linked immunosorbent assay (ELISA) technology. Monodon-type baculovirus (MBV) was purified by sucrose gradient centrifugation from occlusion bodies of MBV-infected postlarvae of P. monodon. MBV DNA was subsequently purified from the occlusion bodies and its presence was confirmed by PCR using primers of the polyhedrin gene. Based on conserved sequences of the DNA polymerase genes of Autographa californica nuclear polyhedrosis virus (AcMNPV) and Lymantria dispar nuclear polyhedrosis virus (LdMNPV), primers were designed and synthesized to yield a 714 bp PCR fragment from MBV. However, the sequence of this fragment revealed low homology with that of LdMNPV and AcMNPV. From the DNA sequence of this fragment, a second set of primers was designed, and using these primers, a 511 bp DNA fragment was amplified only when MBV DNA was the template. DNA templates from AcMNPV, white spot syndrome diseased shrimp, or PMO cells (a cell line derived from the Oka organ of Penaeus monodon) did not give any amplified DNA fragment. Therefore, this primer pair was specific for the diagnosis of MBV. By using intraspleenic immunization of rabbits with purified MBV occlusion bodies, a polyclonal rabbit antiserum against MBV was obtained. This antiserum could detect nanogram levels of MBV, but did not cross react with white spot syndrome virus (WSSV), homogenates of PMO cells, postlarvae, hepatopancreatic tissue or intestinal tissue of black tiger prawns by competitive ELISA. This sensitive method could detect MBV even in tissue homogenates.

Animals↗
PubMed2000

The formation and control of disinfection by-products using chlorine dioxide.

In this study, chlorine dioxide (ClO2) was used as an alternative disinfectant with vanillic acid, p-hydroxybenzoic acid, and humic acid as the organic precursors in a natural aquatic environment. The primary disinfection by-products (DBPs) formed were trihalomethanes (THMs) and haloacetic acids (HAAs). Under neutral conditions (pH = 7) for vanillic acid, more total haloacetic acids (THAAs) than total trihalomethanes (TTHMs) were found, with a substantial increase during the later stages of the reaction. In the case of p-hydroxybenzoic acid, the amount of THAAs produced was minimal. Raising the concentration of ClO2 was not favorable for the control of THAAs in low concentrations of vanillic acid. ClO2 could reduce the total amount of TTHMs and THAAs for higher concentration of vanillic acid. It was found that the humic acid treatment dosage was not significant. Under alkaline conditions (pH = 9), the control of TTHMs and THAAs for the treatment of vanillic acid was better and more economical, however, an appreciable amount of inorganic by-products were observed. Under the same alkaline condition, the control of THAA for the treatment of p-hydroxybenzoic acid was not beneficial and for the treatment of humic acid was not significant.

Chlorine Compounds↗
PubMed2000

The pH and anion effects on the heterogeneous photocatalytic degradation of o-methylbenzoic acid in TiO2 aqueous suspension.

This investigation used UV light of 365 nm and titanium dioxide in aqueous suspension to study the photocatalytic reaction of o-methylbenzoic acid under the influence of pH values, anion additives and the varieties of titanium dioxide. From experimental results, under the condition of 5 g/l TiO2, pH 3 and light intensity of 2.45 mW/cm2, 0.1 mM of o-methylbenzoic acid could be completely decomposed in 2 h. The reaction was faster with lowering pH, and was found to be apparent first-order following Langmuir-Hinshelwood model. In the presence of anion additives, the inhibitive effect of chloride ions was larger than that of sulfate ions under acidic condition for Degussa brand titanium dioxide, but without influence using Janssen brand. Both brands, however, promoted the mineralization of o-methylbenzoic acid (o-MBA).

Anions↗
PubMed1999

Dihydroorotate dehydrogenase B of Enterococcus faecalis. Characterization and insights into chemical mechanism.

Enterococcus faecalis dihydroorotate dehydrogenase B is a heterodimer of 28 and 33 kDa encoded by the pyrK and pyrDb genes. Both subunits copurify during all chromatographic steps, and, as determined by HPLC, one FMN and one FAD are bound per heterodimer. The enzyme catalyzes efficient oxidation of 4-S-NADH by orotate. Isotope effect and pH data suggest that reduction of flavin by NADH at the PyrK site is only partially rate limiting with no kinetically significant proton transfer occurring in the reductive half-reaction; therefore, a group exhibiting a pK of 5.7 +/- 0.2 represents a residue involved in binding of NADH rather than in catalysis. The reducing equivalents are shuttled between the NADH-oxidizing flavin in PyrK and the orotate-reacting flavin in PyrDb, by iron-sulfur centers through flavin semiquinones as intermediates. A solvent kinetic isotope effect of 2.5 +/- 0.2 on V is indicative of rate-limiting protonation in the oxidative half-reaction and most likely reflects the interaction between the isoalloxazine N1 of the orotate-reducing flavin and Lys 168 (by analogy with L. lactis DHODase A). The oxidative half-reaction is facilitated by deprotonation of the group(s) with pK(s) of 5.8-6.3 and reflects either deprotonation of the reduced flavin or binding of orotate; this step is followed by hydride transfer to C6 and general acid-assisted protonation (pK of 9.1 +/- 0.2) at C5 of the product.

Amino Acid Sequence↗
PubMed1999

Biochemical purification of a mammalian slit protein as a positive regulator of sensory axon elongation and branching.

Many neurons in both vertebrates and invertebrates innervate multiple targets by sprouting secondary axon collaterals (or branches) from a primary axon shaft. To begin to identify molecular regulators of axon branch initiation or extension, we studied the growth of single sensory axons in an in vitro collagen assay system and identified an activity in extracts of embryonic spinal cord and of postnatal and adult brain that promotes the elongation and formation of extensive branches by these axons. Biochemical purification of the activity from calf brain extracts led to the identification of an amino-terminal fragment of Slit2 as the main active component and to the discovery of a distinct activity that potentiates its effects. These results indicate that Slit proteins may function as positive regulators of axon collateral formation during the establishment or remodeling of neural circuits.

Amino Acid Sequence↗
PubMed1999

Slit proteins bind Robo receptors and have an evolutionarily conserved role in repulsive axon guidance.

Extending axons in the developing nervous system are guided in part by repulsive cues. Genetic analysis in Drosophila, reported in a companion to this paper, identifies the Slit protein as a candidate ligand for the repulsive guidance receptor Roundabout (Robo). Here we describe the characterization of three mammalian Slit homologs and show that the Drosophila Slit protein and at least one of the mammalian Slit proteins, Slit2, are proteolytically processed and show specific, high-affinity binding to Robo proteins. Furthermore, recombinant Slit2 can repel embryonic spinal motor axons in cell culture. These results support the hypothesis that Slit proteins have an evolutionarily conserved role in axon guidance as repulsive ligands for Robo receptors.

Amino Acid Sequence↗
PubMed1996

Identification and characterization of cAMP-dependent protein kinase and its possible direct interactions with protein phosphatase-1 in marine dinoflagellates.

We have examined the nature of signal transduction involving reversible protein phosphorylation in marine Prorocentrale species. Of particular interest is the marine dinoflagellate Prorocentrum lima in which the tumour promoter okadaic acid is produced and may interfere with signal transduction. We have identified cAMP-dependent protein kinase (PKA) activity in P. lima, P. micans, and P. minimum. The P. lima enzyme was characterized biochemically and appears to consist of two different isoforms in the R2C2 configuration. Whole cell extracts of P. micans and P. minimum treated with the specific PKA inhibitor peptide PKI (5-24) or cAMP demonstrated altered intensities of phosphopeptide 32P labeling, most likely involving regulation of a protein phosphatase via PKA activity. A primary candidate for PKA regulation is protein phosphatase-1 (PP-1), which in P. lima possesses a classical PKA consensus phosphorylation site. We demonstrate that a peptide fragment of PP-1 from P. lima corresponding to this PKA phosphorylation site can be effectively phosphorylated by PKA and dephosphorylated by calcineurin. We speculate that PP-1 activity among several lower eukaryotes may be mediated directly by reversible phosphorylation. Higher eukaryotes may have developed inhibitor proteins to provide more complex regulation of protein phosphatase activity.

Amino Acid Sequence↗
PubMed1994

[Alteration in lipid peroxide content in cerebral cysticercosis].

Serum lipid peroxide (LPO) content in eighty-three cases of cysticercosis cellulosae was determined by the fluorescence method. the results showed that the LPO level in epileptic type and non-epileptic type of cerebral cysticercosis was significantly higher than that in the normal controls (P < 0.01). No significant difference in LPO was observed between epileptic type and non-epileptic type (P > 0.05). The results showed that LPO might play a role in the pathophysiology of cerebral cysticercosis.

Brain Diseases↗
PubMed1993

[Comparative study on antigens of Cysticercus cellulosae by ELIB and ELISA].

Urea-soluble antigens (Ag-u) and water-soluble antigens (Ag-w) of Cysticercus cellulosae were studied by using ELIB and ELISA, respectively. The results showed that using Ag-u and Ag-w, 9 and 14 bands of polypeptides could be recognized by sera from cysticercosis patients; 4 and 10 bands could be recognized by sera from hydatidosis patients; whereas 4 and 8 bands could be recognized by sera from clornochiasis patients. Using ELISA at serum dilutions of 1:400, the positive rate of sera against Ag-u and Ag-w was 96.6% and 86.6%, respectively in 60 cysticercosis patients; 16.6% and 46.6% respectively in 30 hydatidosis patients and negative in 24 clornorchiasis patients and 50 normal healthy persons, indicating that both Ag-u and Ag-w share common antigen components causing cross reaction with the sera from hydatidosis and clonorchiasis patients. However, such components were fewer in Ag-u than in Ag-w. In view of the fact that Ag-u is superior to Ag-w in both sensitivity and specificity, Ag-u might be better used for the diagnosis of cysticercosis.

Animals↗
PubMed1988

[Interstitial photodynamic therapy of oral squamous cancers].

Photodynamic therapy (PDT) was studied in the treatment of a variety of solid malignant tumors. Ten patients with oral squamous cancers treated by PDT are reported: The laser beam was introduced into the malignant and metastatic lymphatic tissues through inserted optic fibers. The results showed that all the lesions gave complete response to PDT except the bony involvement. It was noted that the lymphatic metastatic foci showed a higher photosensitivity, and the covering skin, connective tissue and the nearby organs were not obviously injured. Combination of PDT with chemotherapy, radiotherapy and surgery are also discussed.

Adult↗