Biomedical subjects

W J Tsai

Publications and source records attributed to W J Tsai.

At least 19 recordsLinked to original sources

PubMed2003

Activation and proliferation signals in primary human T lymphocytes inhibited by ergosterol peroxide isolated from Cordyceps cicadae.

Effects of ergosterol peroxide (C28H44O3; Cpd 6A) from Cordyceps cicadae on phytohemagglutinin (PHA)-stimulated cell proliferation were studied in primary human T cells. The results showed that Cpd 6A suppressed T-cell proliferation for about 24 h after stimulation with PHA. Cell cycle analysis indicated that Cpd 6A arrested the cell cycle progression of activated T cells from the G1 transition to the S phase. To localize the point in the cell cycle where arrest occurred, a set of key regulatory events leading to the G1/S boundary, including the expression of cyclins D2, E, A1, and B1, interleukin (IL)-2, IL-4, interferon-gamma (IFN-gamma), and activating protein-1 (AP-1), was examined. Cpd 6A suppressed, in activated T lymphocytes, the production and mRNA expression of cyclin E, IL-2, IL-4, IL-10, and IFN-gamma in a dose-dependent manner. Expression of AP-1 proteins, consisting of c-Fos and c-Jun, in activated T lymphocytes was decreased by Cpd 6A. The kinetic study indicated that the inhibitory effects of Cpd 6A on IL-2 mRNA expressed in T cells might be related to blocking c-Fos protein synthesis. T-cell proliferation after Cpd 6A treatment was partially restored by addition of IL-2, IL-4, and IFN-gamma. These suppressant effects of Cpd 6A on T-cell proliferation, activated by PHA, appeared to be mediated, at least in part, through the inhibition of early gene transcripts, especially those of cyclin E, IFN-gamma, IL-2, and IL-4, and by arresting cell cycle progression in the cells.

Adult↗

PubMed2001

Positional importance of Pro53 adjacent to the Arg49-Gly50-Asp51 sequence of rhodostomin in binding to integrin alphaIIbbeta3.

Rhodostomin (RHO), a disintegrin isolated from snake venom, has been demonstrated to inhibit platelet aggregation through interaction with integrin alphaIIbbeta3, but there is a lack of direct evidence for RHO-integrin alphaIIbbeta3 binding. In addition, no study on the length of Arg(49)-Gly(50)-Asp(51) (RGD) loop of RHO influencing on its binding to integrin alphaIIbbeta3 has been reported. In the present study we have developed a highly sensitive dot-blot and glutathione S-transferase-RHO pull-down assays; the latter was coupled with a biotin-avidin-horseradish peroxidase enhanced-chemiluminescence detection system. These were able to demonstrate the direct binding of RHO to integrin alphaIIbbeta3. The pull-down assay further showed that four alanine-insertion mutants upstream of the RGD motif and three insertions downstream of the RGD were able to decrease integrin alphaIIbbeta3 binding activity to only a limited extent. By contrast, two insertions immediately next to RGD and one insertion in front of the Cys(57) caused almost complete loss of binding activity to alphaIIbbeta3. The results of the platelet-aggregation-inhibition assay and platelet-adhesion assay for the insertion mutants were consistent with results of the pull-down assay. It is thus concluded that, although an insertion of a single alanine residue in many positions of the RGD loop has only minor effects on RHO binding to integrin alphaIIbbeta3, the specific position of Pro(53) residue adjacent to the RGD sequence is important for RHO binding to platelet integrin alphaIIbbeta3.

Alanine↗

PubMed2001

Immune reponses in human mesangial cells regulated by emodin from Polygonum hypoleucum Ohwi.

In the hope of identifying agents of therapeutic value in glomerulonephritis from Chinese herbs, we found that methanolic extracts of Polygonum hypoleucum Ohwi (P. hypoleucum Ohwi) inhibit human mesangial cells proliferation activated with interleukin-1beta (IL-1beta) and interleukin-6 (IL-6) previously. This study was designed to identify bioactive components from P. hypoleucum Ohwi and elucidate their action mechanisms. We tested four anthraquinones emodin, emodin 1-O-beta-D-glucoside (49A), physcion (62A), and physcion 1-O-beta-D-glucoside (50A) purified from P. hypoleucum Ohwi for their effects on human mesangial cell proliferation and cytokines production in vitro. On a percentage basis, emodin had the highest suppressing activity on the human mesangial cells proliferation activated by IL-1beta and IL-6. The IC50 of emodin on human mesangial cells proliferation were 17.9+/-1.2 microM. In contrast to 49A, 50A, and 62A, emodin also decreased IL-1beta, IL-6 and tumor necrosis factor-alpha (TNF-alpha) production in human mesangial cells activated with IL-1beta and IL-6. The IC50 of emodin on IL-1beta, IL-6 and TNF-alpha production in activated human mesangial cells were 16.6+/-1.8 microM, 8.2+/-1.3 microM, and 9.5+/-1.6 microM, respectively. Moreover, IL-1beta and TNF-alpha mRNA expression in activated human mesangial cells was impaired by emodin. The intracellular free Ca2+ concentration ([Ca2+]i) in IL-1beta and IL-6 activated human mesangial cells was decreased by emodin. It is unlikely that cytotoxicity was involved because no cell deaths were observable. We hypothesize that the inhibitory mechanisms of emodin on activated human mesangial cells proliferation may be related to the impairments of gene expression and production of cytokines and [Ca2+]i in the cells.

Calcium↗

PubMed2001

Regulation of bronchoalveolar lavage fluids cell function by the immunomodulatory agents from Cordyceps sinensis.

Cordyceps sinensis (C. sinensis) is one of the well known fungi used in traditional Chinese medicine for treatment asthma and bronchial and lung inflammation. In this study, effects of C. sinensis methanolic extracts on bronchoalveolar lavage fluids (BALF) cells proliferation, inflammatory cytokines production, and genes expression were evaluated. The proliferative response of BALF cells to lipopolysaccharide (LPS) was determined by the tritiated thymidine uptake method. The cell-free supernatants were harvested then tested for interlukin-1beta (IL-1beta), interlukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), interleukin-8 (IL-8), interleukin-10 (IL-10), interleukin-12 (IL-12), and interferon-gamma (IFN-gamma) by the enzyme immunoassay. The results indicated that the CS-19-22 fraction dose dependently suppressed BALF cells proliferation activated by LPS. The CS-19-22 fraction also reduced IL-1beta, IL-6, IL-8, IL-10 and TNF-alpha production in LPS activated BALF cell cultures. Furthermore, the IL-12 and IFN-gamma production in activated BALF cells were enhanced by CS-19-22 treatment. The CS-19-22 fraction did not affect IL-1beta, IL-6, TNF-alpha, and IL-8 mRNAs expression in BALF cells detected by reverse transcription-polymerase chain reaction (RT-PCR). By contrast, the CS-19-22 fraction increased IL-12 and IFN-gamma mRNAs expression and decreased IL-10 mRNA expression in the BALF cells activated with LPS. These results indicated the CS-19-22 fraction suppressed IL-1beta, IL-6, TNF-alpha, and IL-8 cytokines production in BALF cells through other than inhibition of mRNAs expression pathway. These results also demonstrate that the therapeutic activity of C. sinensis in Chinese medicine may be related to modulation of TH1 and TH2 cells functions in bronchial airway.

Adjuvants, Immunologic↗

PubMed2001

Regulation of cell proliferation, inflammatory cytokine production and calcium mobilization in primary human T lymphocytes by emodin from Polygonum hypoleucum Ohwi.

OBJECTIVE AND DESIGN: This study was designed to elucidate action mechanisms of four anthraquinones identified from Polygonum hypoleucum Ohwi (P. hypoleucum Ohwi) on primary human T lymphocytes. MATERIAL AND METHODS: The cells were isolated from peripheral blood. TREATMENT: T cells were treated with 5 to 60 microM of four anthraquinones with or without phytohemagglutinin (PHA; 5 microg/ml) for 3 days. Effects of 4 anthraquinones on T lymphocyte proliferation, production and gene expression of inflammatory cytokines and intracellular free Ca2+ concentration ([Ca2+]i) were determined. Data were assessed with Student's t-test. RESULTS: On a percentage basis, emodin had the highest suppressing activity on T lymphocyte proliferation with an IC50 of 11.2 +/- 0.6 microM. Emodin decreased cytokine production, IL-2 mRNA expression, and [Ca2+]i in activated T cells. CONCLUSIONS: We hypothesize that the inhibitory mechanisms of emodin on activated T cells proliferation are related to the impairment of cytokine production, IL-2 mRNA level and [Ca2+]i in the cells.

Adult↗

PubMed2001

Characterization of stress-responsive genes, hrcA-grpE-dnaK-dnaJ, from phytopathogenic Xanthomonas campestris.

Sequencing of a 6.4-kb DNA fragment, cloned from the plant pathogenic bacterium Xanthomonas campestris pv. campestris 17 revealed five ORFs whose deduced amino acid sequences show strong similarities to the bacterial HrcA, GrpE, DnaK, DnaJ, and PdxK. The four heat shock genes are organized in the order hrcA-grpE-dnaK-dnaJ, a genome organization found in many gram-positive bacteria, but only in one gram-negative species (Xylella fastidiosa). These observations suggest that the HrcA-CIRCE system, comprising at least four genes arranged in this order, already existed for the regulation of stress responses before bacteria diverged into gram-negative and gram-positive groups. Primer-extension results suggested the presence of promoters at the regions upstream of grpE and dnaK. In the presence of stress, heat or ethanol (4%), the X. campestris pv. campestris 17 grpE and dnaK promoters were induced two- to three-fold over controls. Since the grpE and dnaK promoters possess E. coli sigma(32) promoter-like sequences, they are functional in E. coli, although at levels much lower than in X. campestris pv. campestris 17. Furthermore, expression of the X. campestris pv. campestris 17 dnaK promoter in E. coli was elevated by the cloned X. campestris sigma(32) gene, indicating that the cognate sigma(32) works more efficiently for the X. campestris promoters.

Bacterial Proteins↗

PubMed2001

Acetylcholinesterase inhibition and the extrapyramidal syndrome: a review of the neurotoxicity of organophosphate.

Organophosphate poisonings are not uncommon, and are the leading cause of death in suicide patients in Taiwan. Acute cholinergic crisis caused by the inhibition of synaptic acetylcholinesterase is the major manifestation of organophosphate poisoning and may cause death within minutes. Delayed neurotoxicities include intermediate syndrome and delayed polyneuropathy have also been described. However, these symptoms may not characterize the complete picture of organophosphate poisoning. Among the 633 patients ever admitted to our hospital with organophosphate poisoning, three patients were found exhibiting impermanent neuromuscular dysfunction, including blepharoclonus, oculogyric crisis, intermittent dystonia, rigidity, and tremor, with two of them developing mask face, dyskinesia and akathisia later, following acute cholinergic crisis. The symptoms appeared within 4 days with the duration ranging from 25 days to 2 months. Other causes of the extrapyramidal syndrome noted on these patients have been excluded, and we consider the extrapyramidal syndrome a possible neurotoxic manifestation of organophosphate poisoning, which is transient, needs no treatment, and may be missed because of the critical condition, in a minority of patients. The mechanism remains to be identified, but may be related to the impediment of the function of acetylcholinesterase to modify nigrostriatal dopaminergic system, which is independent of hydrolyzing acetylcholine. More detailed observation for organophosphate poisoned patients and more studies for the biological functions of acetylcholinesterase including the influence on the nigrostriatal dopaminergic system are needed.

Acetylcholinesterase↗

PubMed2001

Regulation of herpes simplex virus type 1 replication in Vero cells by Psychotria serpens: relationship to gene expression, DNA replication, and protein synthesis.

Inhibitory effects of ethanolic extracts from seven Chinese herbs on herpes simplex virus type 1 (HSV-1) replication were investigated. From a bioassay-guided fractionation procedure, PS-A-6 was isolated from Psychotria serpens (P. serpens), which suppressed HSV-1 multiplication in Vero cells without apparent cytotoxicity. Time-of-addition experiments suggested that the inhibitory action of PS-A-6 on HSV-1 replication was not through blocking of virus adsorption. In an attempt to further localize the point in the HSV-1 replication cycle where arrest occurred, a set of key regulatory events leading to viral multiplication was examined, including viral gene expression, DNA replication, and structural protein synthesis. The results indicated that gB mRNA and protein expression in Vero cells were impeded by PS-A-6. Southern blot analysis showed that HSV-1 DNA replication in Vero cells was arrested by PS-A-6. In addition, PS-A-6 decreased thymidine kinase (tk) and ICP27 mRNA expression in the cells. The mechanisms of antiviral action of PS-A-6 seem to be mediated, at least in part, through inhibition of early transcripts of HSV-1, such as tk and ICP27 mRNAs, arresting HSV-1 DNA synthesis and gB gene expression in Vero cells. Plans are underway for the isolation of pure compounds from PS-A-6 and elucidation of their mechanism of action.

Animals↗

PubMed2001

Rhabdomyolysis: an unusual feature with mushroom poisoning.

Rhabdomyolysis resulting from mushroom poisoning previously has been unreported in the literature. We present an outbreak of Russula subnigricans poisoning with rhabdomyolysis. The most severely ill patient presented with rhabdomyolysis, severe electrolyte disturbance (hyperkalemia, hypocalcemia), respiratory failure, acute renal failure, pulmonary edema, ventricular tachycardia, and circulatory shock. Mycotoxin may be the cause of rhabdomyolysis. In areas where mushroom gathering is common, mushroom poisoning should be included in the differential diagnosis of rhabdomyolysis.

Female↗

PubMed2001

Food poisoning due to methamidophos-contaminated vegetables.

BACKGROUND: Organophosphate poisoning is well known for its characteristic symptoms and signs, but food poisoning caused by pesticide-contaminated food is seldom reported. CASE REPORT: We report three incidents of food poisoning that resulted from exposure to the organophosphate insecticide methamidophos in vegetables. These outbreaks caused a cholinergic syndrome in 4 patients. The cholinergic overactivity led as to suspect organophosphate food poisoning. All patients recovered well following appropriate therapy. The clinical diagnosis of organophosphate poisoning was confirmed by reduced levels of erythrocytes and plasma cholinesterase and the presence of methamidophos in the vegetable leftovers. The implicated vegetables and levels of methamidophos were: Ipomoea batatas 255 ppm, Gynura bicolor 110 ppm, and red cabbage 26.3 ppm. Since methamidophos is normally applied to vegetables during planting, improper selection and/or overuse of pesticide or improper harvest times may explain the occurrence of these high residue levels of methamidophos.

Adult↗

PubMed2001

Acute toxicities of betel nut: rare but probably overlooked events.

BACKGROUND: Betel nut chewing has long been a social habit in Taiwan and other Asian and tropical countries. It produces various autonomic and psychoneurologic effects including tachycardia, flushing, warmth, cholinergic activation, alertness, and euphoria. Although the oral carcinogenic effects are well known, data concerning its acute toxicity are few. To better understand the toxicity of betel nut, cases reported to the Taiwan Poison Control Center as probable or possible betel nut-related toxicity (January 1988-June 1998) were reviewed. In the 17 cases suitable for review (14 males, 3 females, age 21 to 60 years), the most common manifestations were tachycardia/palpitations (7); tachypnea/dyspnea (6); hypotension and sweating (5); vomiting, dizziness, and chest discomfort (4); abdominal colic, nausea, numbness, and coma (3); and acute myocardial infarction and related manifestations (2). The reported quantity of betel nut used was low (1 to 6 nuts), except an extract of 100 betel nuts was used in 1 case and 66 chewed in another. Most cases recovered within 24 hours after the exposure. One patient developed probable acute myocardial infarction and ventricular fibrillation and died despite repeated cardiac defibrillation. Although betel nut chewing is widespread, significant toxicity as reported to a poison center is rare. Because most betel nut-related effects are transient and mild in nature, the incidence of such events is likely to be underreported. Nevertheless, betel nut chewing can produce significant cholinergic, neurological, cardiovascular, and gastrointestinal manifestations. It is possible that it may aggravate cardiac diseases in susceptible patients but this hypothesis must be further investigated. Treatment is symptomatic. With timely support, rapid and complete recovery is anticipated but a small risk of major complications cannot yet be discounted.

Adult↗

PubMed2001

Acute ethylene chlorohydrin poisoning: experience of a poison control center.

BACKGROUND: Ethylene chlorohydrin (CAS 107-07-3), a chemical once used in hastening grape vine sprouting in Taiwan, has caused severe toxicity upon acute exposure. Although such use of ethylene chlorohydrin is now prohibited in Taiwan, poisoning still occurs following its illegal use. Since data concerning human ethylene chlorohydrin poisoning remain rare, we report our experience in treating acute ethylene chlorohydrin-poisoned patients. METHODS: A retrospective analysis was conducted to evaluate patients with ethylene chlorohydrin poisoning reported to Taiwan Poison Control Center during 1985-1998. RESULTS: Seventeen patients with ethylene chlorohydrin poisoning were identified. There were 11 male and 6 female patients, ranging in age from 2 to 70 years (median 53 years). The intent of exposure was suicide in 5, accident in 9, and occupational exposure in 3 patients. Oral ingestion was the most common route of exposure (14 patients). Seven out of the 17 patients died within 24 hours due to metabolic acidosis and respiratory failure. Ethanol therapy, used in 2 patients, had no apparent benefit. Moderate or mild poisoning was characterized by gastrointestinal effects only and an uneventful recovery. CONCLUSIONS: Ethylene chlorohydrin can result in severe metabolic acidosis, respiratory failure, coma, and death after acute exposure.

Accidents↗

PubMed2001

Cholestatic hepatitis caused by acute gold potassium cyanide poisoning.

INTRODUCTION: Poisoning after oral ingestion of gold potassium cyanide is rarely reported. A case of suicidal ingestion of gold potassium cyanide (potassium dicyanoaurate; CAS# 13967-50-5) is described. CASE REPORT: A 27-year-old man attempted suicide by ingesting 5 mL gold potassium cyanide solution. He developed vomiting, hyperamylasemia, and hepatic dysfunction. Cyanide poisoning was not detected but acute gold toxicity was noted. Pathologic findings of the liver showed centrilobular cholestasis with eosinophilic degeneration. The whole blood and serum gold were 4361 and 6011 microg/L, respectively, and the 24-hour urine gold was 429 microg/d in samples obtained on day 4. CONCLUSION: Gold-induced hepatotoxicity has been seen infrequently in patients receiving gold therapy. Reported agents include sodium aurothiomalate, sodium aurothiopropranol sulfonate, aurothioglucose, aurothiopolypeptide (Auro-detoxin), auric sulfide, and gold thiosulfate, our report adds gold potassium cyanide.

Acute Disease↗

PubMed2001

A case of jellyfish sting.

Jellyfish sting may result in a wide range of symptoms from common erythematous urticarial eruptions to the rare box-jelly induced acute respiratory failure. In Taiwan, with the increasing frequency of international travel, cases of jellyfish sting to foreigners are on the rise. We report a case of jellyfish sting with the rare presentation of painless contact dermatitis. A 38-y-o man accidentally stepped on a sea urchin with his right foot during scuba diving in a beach in Thailand. Traditional therapy with vinegar was applied on the lesion. However, when he returned to Taiwan, erythematous patches on the left thigh with linear radiations to the leg were discovered. The skin lesions had bizzare shapes and showed progressive change. No pain or numbness was noticed. Jellyfish stingwas suspected, topical medications were applied, and the patient recovered without complication. Jellyfish stings usually result in a painful erythematous eruption. In this case, though the lesion involved a large surface, there was no pain. Delayed diagnosis of jellyfish sting was due to the atypical presentation and the physician's unfamiliarity to the Thai jellyfish sting. Awareness to the wide spectrum of jellyfish sting symptoms should be promoted.

Adult↗

PubMed2000

Regulation of cell proliferation, gene expression, production of cytokines, and cell cycle progression in primary human T lymphocytes by piperlactam S isolated from Piper kadsura.

Effects of piperlactam S (C(17)H(13)NO(4); mol. wt. 295) isolated from Piper kadsura on phytohemagglutinin (PHA) stimulated cell proliferation were studied in primary culture of human T cells. The results showed that piperlactam S suppressed T cell proliferation at about 0 to 12 h after stimulation with PHA. Synthesis of total cellular proteins and RNA in activated cell cultures was also suppressed. The inhibitory action of piperlactam S was not through direct cytotoxicity. Cell cycle analysis indicated that piperlactam S arrested the cell cycle progression of activated T cells from the G(1) transition to the S phase. In an attempt to further localize the point in the cell cycle at which arrest occurred, a set of key regulatory events leading to the G(1)/S boundary, including gene expression of cytokines and c-Fos protein synthesis, was examined. Piperlactam S suppressed, in activated T lymphocytes, the production and mRNA expression of cytokines such as interleukin-2 (IL-2), IL-4, and interferon-gamma in a dose-dependent manner. In addition, Western blot analysis indicated that c-Fos protein expressed in activated T lymphocytes was decreased by piperlactam S. Results of kinetic study indicated that inhibitory effects of piperlactam S on IL-2 mRNA expressed in T cells might be related to blocking c-Fos protein synthesis. Thus, the suppressant effects of piperlactam S on proliferation of T cells activated by PHA seemed to be mediated, at least in part, through inhibition of early transcripts of T cells, especially those of important cytokines, IL-2, IL-4, and arresting cell cycle progression in the cells.

Adult↗

PubMed2000

Vandellia cordifolia regulated cell proliferation and cytokines production in human mononuclear cells.

Vandellia cordifolia (V. cordifolia) used for treatment inflammation in traditional Chinese medicine was selected for immunopharmacological activity test. The effects of V. cordifolia extracted fractions on human mononuclear cells (HMNC) proliferation were determined by tritiated thymidine uptake. The results indicated that VC-ME fraction suppressed HMNC proliferation activated with phytohemagglutinin (PHA) and stimulated cell cycle progression was arrested at the G0/G1 stage. The inhibitory mechanisms may involve the blocking of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) production, since VC-ME suppressed IL-2 and IFN-gamma production of HMNC in a dose-dependent manner. Therefore, it is suggested that immunomodulatory agents are contained in V. cordifolia.

Adjuvants, Immunologic↗

PubMed1999

On-line derivatization for continuous and automatic monitoring of brain extracellular glutamate levels in anesthetized rats: a microdialysis study.

Glutamate is an important excitatory amino acid in central nervous system. We developed a method for in vivo, continuous and automatic monitoring of brain extracellular glutamate, as well as other amino acids in anesthetized rat. This method involves the use of microdialysis perfusion technique and a high-performance liquid chromatography system equipped with a fluorescence detector. The microdialysate (perfused at a flow-rate of 1 microl/min) was on-line derivatized with o-phthaldehyde (perfused at 2 microl/min) through a mixing tee prior to the injection onto the HPLC column. The efficiency of this on-line derivatization was equivalent to that performed with an off-line manner. The effect of cerebral ischemia (2 h) and reperfusion (2 h) in brain cortex of anesthetized rats was monitored using this method. In addition to glutamate, extracellular concentrations of other amino acids, such as aspartate, glutamine, glycine, taurine and gamma-aminobutyric acid, were also simultaneously monitored with this on-line method. Since monitoring of extracellular amino acids by microdialysis perfusion is intensively used in neuroscience investigations, this simple and convenient method would be useful in the future applications.

Anesthesia↗

PubMed1999

Blocking of cell proliferation, cytokines production and genes expression following administration of Chinese herbs in the human mesangial cells.

In the hope of identifying agents of therapeutic value in immuoglobulin A nephropathy (IgA-N), we tested crude methanol extracts of 15 Chinese herbs for their effect on human mesangial cell proliferation. The results indicated that 4 out of the 15 crude extracts inhibited human cells proliferation activated by IL-1beta and IL-6. The extracts and their median inhibitory concentrations were as follows (in microg/ml): Ludwiga octovalvis (MLS-052), 49.9 +/- 1.8; Rhus semialata (MLS-053), 31.2 +/- 1.6; Tabernaemontana divaricata (MLS-054), 50.0 +/- 2.1; Amepelopsis brevipedunculata (MLS-059), 42.9 +/- 1.1. These findings indicate that human mesangial cells were most sensitive to MLS-053 treatment. These herbs also decreased interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) production. Moreover, IL- 1beta mRNA expression was inhibited by Rhus semialata (R. semialata; MLS-053). It is unlikely that cytotoxicity was involved, because no cell deaths were observable. We hypothesize that the inhibitory mechanisms of these Chinese herbs may be related to the impairments of gene expression and production of cytokines in human mesangial cells. Plans are underway for the isolation of pure compounds from these Chinese herbs and the elucidation of their mechanisms of action.

Cell Division↗