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Biomedical subjects

W S Chung

Publications and source records attributed to W S Chung.

At least 19 recordsLinked to original sources
PubMed2007

Factors influencing the successful treatment of infectious pulmonary tuberculosis.

SETTING: Achieving successful treatment of infectious pulmonary tuberculosis (PTB) could reduce the spread of tuberculosis (TB) and the emergence of multidrug resistance. OBJECTIVE: To explore factors associated with successful treatment for sputum-positive PTB. DESIGN: This study used a population-based retrospective cohort design. All PTB patients residing in southern Taiwan recorded in the tuberculosis registry from 1 January to 30 June 2003 were identified. Each patient's medical record was requested from treating hospitals and retrospectively reviewed for 15 months after the date PTB was confirmed. RESULTS: There were 399 PTB patients included in the study. Factors significantly associated with successful treatment included treatment by pulmonologists (OR 1.93), receiving directly observed therapy (DOT) (OR 1.76) and receiving treatment at the chest hospital (OR 5.41). Patients of advanced age were less likely to achieve treatment success (OR 0.97). Among patients treated by pulmonologists, those treated at the chest hospital had a significantly higher treatment success rate than those treated at other institutions (94.1% vs. 69.9%). CONCLUSIONS: Patients treated with DOT and by pulmonologists, especially at the chest hospital, had a higher treatment success rate. DOT and training of care professionals and institutions are therefore important factors that affect the successful treatment of TB.

Adolescent↗
PubMed2006

Botulinum toxin A for the management of vulvodynia.

Clinically, botulinum toxin A blocks the cholinergic innervation of the target tissue. Recently, it has been proved effective not only at a neuromuscular junction but also within parasympathetic or sympathetic neural synapses. Seven women with pain on genitalia that could not be controlled with conventional pain managements were enrolled in this study. Twenty to 40 U of botulinum toxin A were used in each injection. Injection sites were the vestibule, levator ani muscle or the perineal body. Repeat injections were administered every 2 weeks if the patient's symptoms had not fully subsided. In all patients, pain had disappeared with botulinum toxin A injections. Five patients needed to be injected twice; the other two patients needed only one injection. We did not observe complications related to botulinum toxin A injections, such as pain, hemorrhage, infection, muscle paralysis or other complications. The subjective pain score improved from 8.3 to 1.4, and no one has experienced a recurrence (the follow-up period was four to 24 months, with a mean follow-up of 11.6 months). Botulinum toxin A is effective in blocking nociception. Even though further investigation and well-controlled study will be necessary, we suggest that the botulinum toxin therapy would be useful and safe in managing vulvodynia of muscular or neuroinflammatory origins.

Adult↗
PubMed2006

Gene expression profiling of human synovial sarcoma cell line (Hs701.T) in response to IL-1beta stimulation.

OBJECTIVE: Synovial sarcoma (SS) is a malignant mesenchymal tumor that accounts for 5-10% of all soft tissue sarcoma. IL-1beta, a pleiotrophic cytokine, has been found in the tumor microenvironment which plays crucial roles in the pathogenesis of tumors. METHODS: In this study, we used Hs701.T as a cellular model to study the short-term (4-h) and long-term (48-h) stimulatory effect of IL-1beta on cell proliferation and differential gene expression. RESULTS: The results showed that IL-1beta can stimulate cell proliferation through activation of NF-kappaB and AP-1 transcription factors; sequentially triggers the expression of genes related to tumor progression. The microarray data indicated that most of the up-regulated genes were related to tumor progression. Five candidate genes which are involved in the mediation of proliferation (IL-6), apoptosis (Hsp27 and Daxx), and angiogenesis (PlGF and SPARC) were further validated by RT-PCR. CONCLUSION: These findings may be useful for understanding the pathogenesis of synovial sarcoma.

Cell Line, Tumor↗
PubMed2006

AtBAG6, a novel calmodulin-binding protein, induces programmed cell death in yeast and plants.

Calmodulin (CaM) influences many cellular processes by interacting with various proteins. Here, we isolated AtBAG6, an Arabidopsis CaM-binding protein that contains a central BCL-2-associated athanogene (BAG) domain. In yeast and plants, overexpression of AtBAG6 induced cell death phenotypes consistent with programmed cell death (PCD). Recombinant AtBAG6 had higher affinity for CaM in the absence of free Ca2 + than in its presence. An IQ motif (IQXXXRGXXXR, where X denotes any amino-acid) was required for Ca2 +-independent CaM complex formation and single amino-acid changes within this motif abrogated both AtBAG6-activated CaM-binding and cell death in yeast and plants. A 134-amino-acid stretch, encompassing both the IQ motif and BAG domain, was sufficient to induce cell death. Agents generating oxygen radicals, which are known to be involved in plant PCD, specifically induced the AtBAG6 transcript. Collectively, these results suggest that AtBAG6 is a stress-upregulated CaM-binding protein involved in plant PCD.

Amino Acid Motifs↗
PubMed2004

Prediction of corrosion rates of water distribution pipelines according to aggressive corrosive water in Korea.

The drinking water network serving Korea has been used for almost 100 years. Therefore, pipelines have suffered various degrees of deterioration due to aggressive environments. The pipe breaks were caused by in-external corrosion, water hammer, surface loading, etc. In this paper, we focused on describing corrosion status in water distribution pipes in Korea and reviewing some methods to predict corrosion rates. Results indicate that corrosive water of lakes was more aggressive than river water and the winter was more aggressive compared to other seasons. The roughness growth rates of Dongbok lake showed 0.23 mm/year. The high variation of corrosion rates is controlled by the aging pipes and smaller diameter. Also the phenolphthalein test on a cementitious core of cement mortar lined ductile cast iron pipe indicated the pipes over 15 years old had lost 50-100% of their lime active cross sectional area.

Corrosion↗
PubMed2001

Effects of estrogen on nitric oxide synthase and histological composition in the rabbit clitoris and vagina.

We investigated the functional and histological changes after oophorectomy in the rabbit clitoris and vagina to determine the mechanism responsible for the development of arousal disorder in postmenopausal women. Twenty mature female New Zealand white rabbits were randomly divided into three groups: control; oophorectomy; and estrogen replacement after oophorectomy. We compared the nitric oxide synthase (NOS) activity and the degree of expression of neuronal (nNOS) and endothelial NOS (eNOS) using biochemical and Western blot analysis in clitoral and vaginal tissues. Histological change of smooth muscle and collagen contents in those tissues were also compared using Masson's trichrome staining. NOS activity and the expression of nNOS and eNOS were significantly increased in the oophorectomized group while there was a decrease to the level of the control group in the estrogen replacement group. Histological examination showed that oophorectomy induced a significant increase in collagen and decrease in muscle content in both clitoris and vagina, while the ratio of smooth muscle content was increased significantly after the estrogen replacement. Our results clearly demonstrate that estrogen deficiency induces compensatory NOS production which may be related to decreases in muscle to collagen ratio in female rabbit genital organs.

Animals↗
PubMed2001

Carbon monoxide poisoning as a new method of suicide in Hong Kong.

The incidence in Hong Kong of intentional carbon monoxide poisonings by burning charcoal in a confined space was investigated. In the two-year study period, 22 (39 percent) of the 56 reported cases occurred in the three months following a highly publicized case in which this method was used to commit suicide; no cases were reported before the publicized incident. Individuals who used this method were younger on average (mean, 39 years) than those who used the more common methods of jumping (mean, 47 years) and hanging (mean, 55 years). The authors speculate that this form of suicide is becoming more prevalent because it has been highly publicized, it is easily carried out, and it is culturally acceptable.

Adult↗
PubMed2001

Cell cycling status of human cord blood CD34+ cells during ex vivo expansion is related to the level of very late antigen expression.

Very late antigen-4 (VLA-4), which binds to the extracellular matrix protein fibronectin, is an integrin molecule known to be modulated during mobilization of CD34+ cells, and to be involved in signaling the mobilization stimuli. On the hypothesis that cell cycling status might be different depending on the level of VLA-4 expression, we investigated the DNA contents of human cord blood CD34+ cells during ex vivo expansion by recombinant human thrombopoietin and flt3-ligand with simultaneous measurement of surface VLA-4 at the 1st and 4th week. During this ex vivo expansion, expression of VLA-4 increased and almost all cells became VLA-4+ until the 4th day of culture. Expression of VLA-4 was maintained in the major population of the cultured cells until the 4th week. The cells in S/G2/M phase were greater in number in VLA-4 high fraction than in VLA-4 low fraction (n=4, p<.001). Furthermore, the fraction of cells in S/G2/M phase increased as the expression of VLA-4 became higher. These results suggest that cord blood CD34+ cells expressing high levels of VLA-4 have more proliferative activities.

Antigens, CD34↗
PubMed2000

Hemodynamic insult by vascular risk factors and pharmacologic erection in men with erectile dysfunction: Doppler sonography study.

To evaluate the penodynamic impact of known vascular risk factors in men with erectile dysfunction, we obtained thorough medical histories covering diabetes, hypertension, heart disease and hypercholesterolemia, alcohol ingestion, and smoking in 265 consecutive patients. We also measured their penile hemodynamic parameters by color duplex ultrasonography after intracavernous prostaglandin E1 injection. In patients with vascular risk factors there was a statistically significant decrease in the peak systolic velocity and increase in the end-diastolic velocity of the cavernosal artery (P < 0.01). Those men who had diabetes had higher average end-diastolic velocities and lower resistance indices (P < 0.01). Smoking and alcohol use also affected penile hemodynamics (P < 0.05). These data confirm that vascular risk factors do increase the likelihood of vasculogenic impotence and that diabetes plays a major role in veno-occlusive dysfunction in the penis.

Adolescent↗
PubMed2000

Multicenter study of the treatment of erectile dysfunction with transurethral alprostadil (MUSE) in Korea.

A Korean multicenter study was conducted to assess the effectiveness of transurethral alprostadil with MUSE in 334 subjects with chronic erectile dysfunction (ED) who were enrolled in 21 clinical centers. Patients with psychogenic impotence comprised about 30% of subjects. Intraurethral alprostadil was titrated in a stepwise fashion in the clinics from 250 to 500 or 1000 mcg based on erectile response and tolerability. The erectile responses were evaluated using an erection assessment scale (score of 1-5). The dose that produced a maximal penile response of score 5 (full rigid erection) or 4 (full tumescence, partial rigidity) was selected for home treatment. Patients who showed partial erection (score of 3) with 1000 mcg were also included in the home-treatment group. In-clinic phase: 198 men (59.3%) had maximal penile responses of score 4 or 5. The rate of maximal responses was not related to patient age, etiology or duration of the ED. A total of 228 (68.3%) men progressed to home treatment. The overall level of comfort of the transurethral alprostadil was rated as uncomfortable or very uncomfortable in 12%. Home phase: During the two-month period of home treatment, 178 (78.1%) men had successful sexual intercourse at least once, and 78.2% of administrations (1976) resulted in successful intercourse. The main causes of drop-out were insufficient erectile response in 27 men (11.8%), adverse reactions (mostly penile or urethral pain) in 7 (3.1%) or both in 7 (3.1%). In conclusion, transurethral alprostadil could be a suitable treatment option for patients with ED regardless of age and etiology of ED. Efficacy in an Asian population (Korea) is comparable to that reported previously in Caucasians.

Adult↗
PubMed2000

Involvement of brassinosteroids in the gravitropic response of primary root of maize.

Exogenously applied brassinolide (BL, 10(-9)-10(-5) M) increased gravitropic curvature in maize (Zea mays) primary roots. The BL-enhanced gravitropic curvature was clearly promoted in the presence of indole-3-acetic acid (IAA, 10(-10)-10(-8) M), indicating that BL is interactive with IAA during the gravitropic response. The interactive effect between BL and IAA was completely diminished by treatment of p-chlorophenoxy isobutric acid, an auxin action antagonist. The activation of the gravitropic response by BL in the absence and in the presence of IAA was nullified by application of 2, 3,5-triiodobenzoic acid, a polar auxin transport inhibitor. The data indicate that brassinosteroids (BRs) might be involved in auxin-mediated processes for the gravitropic response. Gas chromotography-selected ion-monitoring analysis revealed that maize primary roots contained approximately 0.3 ng g(-1) fresh weight castasterone as an endogenous BR. Exogenously applied castasterone also increased the gravitropic response of maize roots in an IAA-dependent manner. This study provides the first evidence, to our knowledge, for occurrence and gravitropic activity of BRs in plant roots.

Brassinosteroids↗
PubMed2000

Identification of a calmodulin-regulated soybean Ca(2+)-ATPase (SCA1) that is located in the plasma membrane.

Ca(2)+-ATPases are key regulators of Ca(2+) ion efflux in all eukaryotes. Animal cells have two distinct families of Ca(2+) pumps, with calmodulin-stimulated pumps (type IIB pumps) found exclusively at the plasma membrane. In plants, no equivalent type IIB pump located at the plasma membrane has been identified at the molecular level, although related isoforms have been identified in non-plasma membrane locations. Here, we identify a plant cDNA, designated SCA1 (for soybean Ca(2+)-ATPase 1), that encodes Ca(2+)-ATPase and is located at the plasma membrane. The plasma membrane localization was determined by sucrose gradient and aqueous two-phase membrane fractionations and was confirmed by the localization of SCA1p tagged with a green fluorescent protein. The Ca(2+)-ATPase activity of the SCA1p was increased approximately sixfold by calmodulin (K(1/2) approximately 10 nM). Two calmodulin binding sequences were identified in the N-terminal domain. An N-terminal truncation mutant that deletes sequence through the two calmodulin binding sites was able to complement a yeast mutant (K616) that was deficient in two endogenous Ca(2+) pumps. Our results indicate that SCA1p is structurally distinct from the plasma membrane-localized Ca(2+) pump in animal cells, belonging instead to a novel family of plant type IIB pumps found in multiple subcellular locations. In plant cells from soybean, expression of this plasma membrane pump was highly and rapidly induced by salt (NaCl) stress and a fungal elicitor but not by osmotic stress.

Amino Acid Motifs↗
PubMed2000

Mobilization kinetics of CD34(+) cells in association with modulation of CD44 and CD31 expression during continuous intravenous administration of G-CSF in normal donors.

The aim of the present study is to evaluate the kinetics of CD34(+) cells and investigate the potential modulation of CD44 and CD31 expression on CD34(+) cells during continuous i.v. administration of G-CSF, thus to elucidate the possible mechanism of peripheral blood progenitor cell (PBPC) mobilization. Fifteen healthy donors were enrolled in this study. G-CSF (10 microg/kg/day) was administered for four consecutive days through continuous 24-h i.v. infusion. For measurement of complete blood counts, CD34(+) cell levels and their expression of CD44 and CD31, PB sampling was performed immediately before the administration of G-CSF (steady-state) and after 4, 8, 24, 48, 72, 96, and 120 h of G-CSF administration. The percentage and absolute number of CD34(+) cells significantly increased at day 3 (0. 55 +/- 0.09%, 51.12 +/- 24.83 x 10(3)/ml) and day 4 (0.47 +/- 0.09%, 46.66 +/- 24.93 x 10(3)/ml), compared to the steady-state level (0. 06 +/- 0.09%, 2.03 +/- 5.69 x 10(3)/ml). At day 3 to day 5 following the onset of G-CSF administration, a strong decrease of CD44 and CD31 expression was observed on mobilized CD34(+) cells compared to controls: the relative fluorescence intensity of CD44 and CD31 was, respectively, 50%-70% and 40%-90% lower than that of controls. We conclude that continuous i.v. administration of G-CSF apparently results in more rapid mobilization of CD34(+) cells, and downregulation of CD44 and CD31 on CD34(+) cells is likely to be involved in the mobilization of PBPC after treatment with G-CSF.

Adult↗
PubMed1999

Competitive binding of calmodulin isoforms to calmodulin-binding proteins: implication for the function of calmodulin isoforms in plants.

In plants, multiple calmodulin (CaM) isoforms exist in an organism which vary in their primary structures in as much as 32 residues out of their 148 amino acids. These CaM isoforms show differences in their expression patterns and/or target enzyme activation ability. To further understand the biological significance of CaM isoforms, we examined whether CaM isoforms act on specific regulatory targets. In gel overlay assays on various soybean tissue extracts, surprisingly, two soybean CaM isoforms (SCaM-1 and SCaM-4) did not show significant differences in their target binding protein profiles, although they exhibited minor differences in their relative target binding affinities. In addition, both SCaM isoforms not only effectively bound five known plant CaMBPs, but also showed competitive binding to these proteins. Finally, immunolocalization experiments with the SCaM proteins in sections of various tissues using specific antibodies revealed similar distribution patterns for the SCaM isoforms except for root tissues, which indicates that the SCaM isoforms are concomitantly expressed in most plant tissues. These results suggest that CaM isoforms may compete for binding to CaMBPs in vivo. This competitive nature of CaM isoforms may allow modulation of Ca(2+)/CaM signaling pathways by virtue of relative abundance and differential target activation potency.

Binding, Competitive↗