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H C Wang

Publications and source records attributed to H C Wang.

At least 37 records · Page 2Linked to original sources
PubMed2001

CD43 potentiates CD3-induced proliferation of murine intestinal intraepithelial lymphocytes.

The involvement of CD43 in cell proliferation of murine intestinal intraepithelial lymphocytes (IEL) has been studied in in vitro CD3-stimulated cell cultures. In the presence of either IL-2 or IL-15, CD3 stimulation of IEL resulted in low levels of proliferation as measured by thymidine incorporation, whereas no proliferation occurred upon CD3 stimulation in the absence of cytokines. The combination of both cytokines to IEL cultures synergistically enhanced CD3-induced proliferation by approximately threefold that of cultures supplemented with either cytokine alone. Most importantly, however, proliferation of IEL was significantly greater when CD3 stimulation occurred in conjunction with CD43 triggering, indicating that CD43 functions as a coactivational signal for murine IEL. These findings indicate that a spectrum of potential proliferative responses exist among murine IEL depending on the types and combinations of signals received, and that because under normal conditions murine IEL are largely devoid of CD28 expression, a classical T-cell coactivational molecule, the capacity for high-level IEL proliferation may reside with CD43.

Animals↗
PubMed2001

Prevalence and significance of hepatitis B virus (HBV) pre-S mutants in serum and liver at different replicative stages of chronic HBV infection.

Several types of naturally occurring pre-S mutants in sera or liver tissues in patients with chronic hepatitis B virus (HBV) infection have been identified. To clarify the prevalence and significance of emergence of pre-S mutants, 140 sera and 18 resected livers from patients with HBV were studied. Replicative status was designated as high, intermediate, and low based on the HBV-DNA levels in serum or the expression of HBV antigens in liver. In vitro transfection and Western blot analysis were performed to characterize expression and secretion of HBsAg by the mutant constructs. Five major types (I to V) of pre-S deletion mutants in serum and liver and 2 types (VI and VII) in liver were identified. Pre-S mutant was 6.4% at high replicative phase, 13% at intermediate, and 37.5% at low or nonreplicative phases in serum. In livers, the same tendency existed: pre-S2 deletion mutants emerged and prevailed at a low replicative phase in hepatocytes that expressed a novel marginal pattern of HBsAg and usually clustered in groups. The deletion sequence of pre-S2 region coincides with human leukocyte antigen-restricted T- and B-cell epitopes. In vitro HBsAg was retained in the hepatocytes and synthesis and secretion of major surface antigen decreased for most of the pre-S mutants. Pre-S mutants prevailed with evolution of chronic HBV, probably under immune pressure. Emergence of pre-S mutants may account for the life-long persistence and discrepancy of HBsAg in serum and liver in HBV and may confer growth advantage in view of the clustering proliferation of hepatocytes harboring pre-S2 mutant.

Blotting, Western↗
PubMed2001

Effective treatment of small murine hepatocellular carcinoma by dendritic cells.

Hepatocellular carcinoma (HCC) is a common malignancy with a poor prognosis. This investigation examined whether dendritic cell-based immunotherapy can treat murine HCC effectively. Bone marrow-derived dendritic cells were propagated from C57BL/10J mice in GM-CSF (4 ng/mL) and interleukin (IL)-4 (1,000 micro/mL). The dendritic cells were pulsed with a Hepa1-6 lysate overnight and employed to treat murine HCC. For in vivo study, HCC was created by inoculation of hepa1-6, 5 x 10(5) cells, in the flank of C57BL/10J mice. HCC were categorized into small (3 x 3-mm) and large (5 x 5-mm) tumors. These HCC were treated by dendritic cells intravenously, twice at weekly intervals. The results revealed that lymphocytes could be gathered around small HCC after administration of Hepa1-6 lysate-pulsed dendritic cells. Seven of 12 (58.3%) small HCC could be eradicated completely by dendritic cell-based immunotherapy, and 33.3% of the small tumors responded to immunotherapy partially which were held in a stable condition for 34.0 +/- 7.4 days before the tumors regrew. For large HCC, lymphocytes did not gather around the tumors, and the tumors cannot be eradicated effectively by dendritic cells. However, dendritic cell-based immunotherapy could slow down the growth rate of large tumors (116.2 +/- 91.4 mm(3) vs. 234.0 +/- 149.1 mm(3) of the control on day 7, P =.043; and 280.3 +/- 224.7 mm(3) vs. 870.0 +/- 418.9 mm(3) of the control on day 17, P <.001). Conclusively, dendritic cells pulsed with a Hepa1-6 lysate can be employed to treat small HCC in vivo effectively. However, the efficacy of dendritic cell-based immunotherapy decreases while tumors grow.

Animals↗
PubMed2001

Analysis of codon usage patterns of bacterial genomes using the self-organizing map.

Codon usage varies both between organisms and between different genes in the same organism. This observation has been used as a basis for earlier work in identifying highly expressed and horizontally transferred genes in Escherichia coli. In this work, we applied Kohonen's self-organizing map to analysis of the codon usage pattern of the Escherichia coli, Aquifex aeolicus, Archaeoglobus fulgidus, Haemophilus influenzae RD:, Methanococcus jannaschii, Methanobacterium thermoautotrophicum, and Pyrococcus horikoshii genomes for evidence of highly expressed genes and horizontally transferred genes. All of the analyzed genomes had a clear category of horizontally transferred genes, and their apparent percentages ranged from 7.7% to 21.4%. The apparent percentage of highly expressed genes ranges from 0% to 11.8%. A clustering of average codon usage of main gene categories of the seven genomes showed an interesting mixing of gene classes in four thermophilic/hyperthermophilic organisms, A. aeolicus, A. fulgidus, M. thermoautotrophicum, and P. horikoshii, which suggests possible origins of their horizontally transferred genes as well as the need for adaptation to a specific environment. Further classification of the three gene categories in E. coli and H. influenzae according to gene function revealed that genes involved in communication (such as regulation and cell process) and structure (cell structure and structural proteins) are more likely to be horizontally transferred than are genes involved in information (transcription, translation, and related processes) and in some groups of energy (such as energy metabolism and carbon compound catabolism).

Archaeoglobus fulgidus↗
PubMed2001

Determination of beryllium and selenium in human urine and of selenium in human serum by graphite-furnace atomic absorption spectrophotometry.

For human urine beryllium (Be), each sample (500 microl) was diluted (1+1) with Nash reagent (containing 0.2% (v/v) acetylacetone and 2.0 M ammonium acetate buffer at pH 6.0) and then a 20-microl volume of Triton X-100 (0.4%, v/v) aqueous solution was added. An aliquot (10 microl) of the diluted urine mixture was introduced into a graphite cuvette and was atomized according to a temperature program. The method detection limit (MDL, 3sigma) for Be was 0.37 microg/l in the undiluted urine sample and the calibration graph was linear up to 65.0 microg/l. Calibration graphs were prepared by the standard addition method. Accuracies of 98.6-102% were obtained when testing standard reference material (SRM 2670) freeze dried human urine samples. Precision (relative standard deviation, RSD) for urine Be was < or = 2.3% (withinrun, n = 5) and was < or = 3.0% (between-run, n = 3). For human urine and serum selenium (Se), samples (100 microl) were diluted with HNO3 (0.2%, v/v) to make a (1+1) dilution for urine analysis or a (1+4) dilution for serum analysis. An additional aliquot (10 microl) of Triton X-100 (0.1%, v/v) was added to each 200 microl of (1+1) diluted urine (or 20 microl of the Triton X-100 was added to each 500 microl of (1+4) diluted serum) sample. After the diluted sample mixture (10 microl) was introduced into a graphite cuvette, the corresponding chemical modifier (10 microl, containing Ni2+ + Pd + NH4NO3 in HNO3 (0.2%, v/v)) was added to it and the mixture was atomized. The MDL (3sigma) for Se in urine and in serum was 4.4 and 21.4 microg/l in undiluted sample, respectively, and the calibration graphs were linear up to 150 and 400 microg/l. Accuracies of urine Se were 98.9 - 99.4% by testing SRM 2670 (NIST) urine standards with RSD (between-run, n = 3) within 2.9%; and that of serum Se was 97.2% when testing a certified second-generation human serum (No. 29, #664) with RSD (between-run, n = 3) of 1.4%. The proposed method can be applied easily, directly, and accurately to the measurement of Be and Se in real samples (including six urine Se and four serum Se from patients of Blackfoot Disease in Taiwan).

Beryllium↗
PubMed2001

Alpha-lactose monohydrate single crystals as hosts for matrix isolation of guest biopolymers.

Single crystals of alpha-lactose monohydrate show a remarkable tendency to include biopolymers, such as proteins, oligonucleotides and dextrans, within the growing lattice. Glycosylation increased the amount of protein contained within the crystals. The guest molecules were found only within the (010) growth sector of the hatchet shaped crystals, thereby binding preferentially to one of the seven developed crystal faces. The topographical features of the active surface are described.

Animals↗
PubMed2001

Changes in the performance of schedule-induced polydipsia (SIP) in rats after arecoline and amphetamine treatments.

This study investigated the performance of schedule-induced polydipsia (SIP) rats in novel or intermittent-reward SIP sessions after arecoline (AREC) and amphetamine sulfate (AMPH) treatments. Either automatic monitors or observers extensively examined the functional changes of parameters in behavioral performance followed by increasing drug dosage. The parameters included locomotion and stereotyped behaviors in the novel sessions; schedule-induced licks, water intake, schedule-dependent nose-pokes, pellets earned and stereotyped behaviors of the facultative stage in the SIP sessions. It was found that when the rats received AMPH (0.5 - 2.0 mg/kg) but not AREC (0.1 - 1.6 mg/kg) in the novel sessions, locomotion increased in a dose-dependent manner. However, when AREC (0.8 mg/kg) and AMPH (1.0 mg/kg) were both given, the effect of AMPH on locomotion was significantly attenuated. In the SIP sessions, a single injection of AMPH increased the number of schedule-dependent nose-pokes at a dose of 1.0 mg/kg, whereas it decreased the number of schedule-induced licks and the amount of water intake at a dose of 2.0 mg/kg. On the other hand a single injection of AREC caused no operant behavior changes at doses below 0.8 mg/kg. However, when the dose was increased to over 0.8 mg/kg (1.6 mg/kg), the number of schedule-induced licks and water intake increased, but the number of schedule-induced nose-pokes decreased. The effects of large doses of AREC on SIP were attenuated after co-administration of scopolamine (0.1 mg/kg), a muscarinic receptor antagonist. Furthermore, the effects of AMPH on SIP performance were not changed by co-administration of AREC at a dose of 0.8 mg/kg. These results are discussed based on the hypothesis that combined utilization of the main component in chewing betel quid, AREC, and AMPH may yield changes of AMPH-induced psychomotor responses in a special environmental context.

Animals↗
PubMed2001

Immune function of thyroid stimulating hormone and receptor.

Thyroid stimulating hormone (TSH) is a central component of the hypothalamus-pituitary-thyroid axis. Although TSH is known for its important biological effects as a neuroendocrine used to regulate thyroid hormone activity and subsequent metabolic functions, TSH also has been shown to be produced and used by cells ofthe mammalian immune system. Moreover, recent findings have linked the use of TSH by cells of the immune system in humans and mice to a group of monocytic cells and lymphocytes--primarily dendritic cells, macrophages, and subset of naïve peripheral T cells. Other studies have demonstrated the capacity of dendritic cells and monocytes to produce biologically active TSH, thereby pointing to a process of paracrine or autocrine TSH-mediated communication during the earliest stages of an immune response to antigen. In this article, these and other features of TSH immune-endocrine interactions are discussed in the context of an intrinsic TSH immunological pathway. Additionally, a hypothesis is proposed in which TSH produced by cells of the immune system during acute antigen exposure plays a dual role, consisting on the one hand of TSH communication during antigen-driven immune activation while concomitantly serving to regulate physiological homeostasis by modulating and adjusting thyroid hormone activity.

Animals↗
PubMed2000

Interaction of shrimp ras protein with mammalian caveolin-1.

BALB/3T3 cells were transformed by transfection with DNA encoding the mutated ras(Q(61)K) from shrimp Penaeus japonicus (Huang and Chuang. 1999. J Exp Zool 283:510-521). The caveolin-1 in the membrane fraction extractable with 2% octyl glucoside was significant reduced, compared to untransformed cells. To understand this in more detail, the interaction of S-Ras with caveolin was investigated using caveolin-1 purified from rat lungs. The purified caveolin-1 binds c-Src, suppressing its autophosphorylation. It also binds to phosphatidylserine-cholesterol liposomes. These reconstituted caveolin-phosphatidylserine-cholesterol vesicles, which act as a model of caveolae, recruit both bacterially expressed S-Ras and rat K(B)-Ras proteins, as demonstrated on western blots with antibodies against caveolin-1 and Ras. Caveolin-1 suppressed the intrinsic GTPase activity of S-Ras, sustaining it in the active GTP bound form. By contrast, caveolin-1 enhanced the intrinsic GTPase activity of K(B)-Ras, to convert it into the inactive GDP-bound form. These events suggest that caveolin may act as a docking site for Ras proteins and may be able to either maintain or alter their activity state. These events may be associated with the ability of S-ras(Q(61)K) to successfully transform cells.

3T3 Cells↗
PubMed2000

Detection of a novel quiescence-dependent protein kinase.

We have identified a cell quiescence-specific 33-kDa cytoplasmic protein kinase (p33(QIK), Quiescence-Induced Kinase) based on induction of p33(QIK)-specific kinase activity of cells growth-arrested in the quiescent phase and deactivation upon entry into the cell cycle. Blockage of macromolecular synthesis prevents p33(QIK) from deactivation, indicating a requirement of newly synthesized regulators for deactivation of p33(QIK) during G(0)/G(1) transition. Stress shock induces additional increases of p33(QIK) activity in a quiescence-dependent manner that correlates with induction of apoptosis. Using a specific antibody to Krs1/Mst2 protein, we found that p33(QIK) is related to p63(Krs1) and is distinguishable from a 36-kDa protein kinase, which is induced through proteolytic modification of activated p63(Krs1) in proliferating cells undergoing apoptosis. p33(QIK) is constantly expressed in quiescent, proliferating, and apoptotic quiescent cells. Regulation of p33(QIK) activity involves protein phosphorylation/dephosphorylation in a proteolysis-independent manner. Regulation of p33(QIK) and related p63(Krs1) and p36 appears to involve distinct pathways in quiescent and proliferating cells, respectively. Our results illustrate the relevance of p33(QIK) activity for cell quiescence that may provide a new insight into signaling pathways regulated in cells during quiescence and quiescence-related apoptosis.

3T3 Cells↗
PubMed2000

Oxidative stress disrupts glucocorticoid hormone-dependent transcription of the amiloride-sensitive epithelial sodium channel alpha-subunit in lung epithelial cells through ERK-dependent and thioredoxin-sensitive pathways.

The amiloride-sensitive epithelial Na(+) channel (ENaC) plays a critical role in the maintenance of alveolar fluid balance. It is generally accepted that reactive oxygen and nitrogen species can inhibit ENaC activity and aggravate acute lung injury; however, the molecular mechanism for free radical-mediated ENaC inhibition is unclear. Previously, we showed that the expression of the alpha-subunit of ENaC, alpha-ENaC, which is indispensable for ENaC activity, is repressed by Ras activation in salivary epithelial cells. Here, we investigated whether exogenous H(2)O(2) modulates alpha-ENaC gene expression in lung epithelial cells through a similar molecular mechanism. Utilizing transient transfection reporter assays and site-directed mutagenesis analyses, we found that the glucocorticoid response element (GRE), located at -1334 to -1306 base pairs of the alpha-ENaC 5'-flanking region, is the major enhancer for the stimulated alpha-ENaC expression in A549 lung epithelial cells. We further demonstrate that the presence of an intact GRE is necessary and sufficient for oxidants to repress alpha-ENaC expression. Consistent with our hypothesis, exogenous H(2)O(2)-mediated repression of alpha-ENaC GRE activity is partially blocked by either a specific inhibitor for extracellular signal-regulated kinase (ERK) pathway activation, U0126, or dominant negative ERK, suggesting that, in part, activated ERK may mediate the repressive effects of H(2)O(2) on alpha-ENaC expression. In addition, overexpression of thioredoxin restored glucocorticoid receptor action on the alpha-ENaC GRE in the presence of exogenous H(2)O(2). Taken together, we hypothesize that oxidative stress impairs Na(+) transport activity by inhibiting dexamethasone-dependent alpha-ENaC GRE activation via both ERK-dependent and thioredoxin-sensitive pathways. These results suggest a putative mechanism whereby cellular redox potentials modulate the glucocorticoid receptor/dexamethasone effect on alpha-ENaC expression in lung and other tight epithelia.

Butadienes↗
PubMed2000

Crystallization and preliminary crystallographic studies of bar-headed goose fluoromethaemoglobin with inositol hexaphosphate.

Bar-headed goose fluoromethaemoglobin (fluoromet-Hb) complexed with inositol hexaphosphate (IHP) has been crystallized using PEG 6000 as precipitant. The crystal belongs to space group P2(1), with unit-cell parameters a = 59.8, b = 72.0, c = 79.8 A, beta = 102.1 degrees, and diffracts to 2.5 A resolution. To prove the presence of IHP, the structure was determined by the molecular-replacement method. IHP was observed at the entrance to the central cavity between the N and C termini of two beta subunits.

Allosteric Regulation↗
PubMed2000

Lack of evidence of association of p21WAF1/CIP1 polymorphism with lung cancer susceptibility and prognosis in Taiwan.

An association between the Arg allele of the p21WAF1/CIP1 codon 31 polymorphism and lung cancer has been reported. However, the genotype distribution of the p21 codon 31 polymorphism, as well as the association of this polymorphism with lung cancer risk and prognosis, remain undefined in the Taiwanese population. Therefore, we investigated the genotype distribution of the p21 codon 31 polymorphism in 155 lung cancer patients and 189 non-cancer controls. The genotype frequencies in the Taiwanese non-cancer controls were 0.51 (Ser) and 0.49 (Arg). Chi2 analysis indicated significant differences in Taiwanese genotype distribution of p21 from those reported for Swedes (P=0.001), Caucasians (P=0.001), Indians (P=0.001), and African-Americans (P=0.001). However, our data did not demonstrate an association of the Arg allele of the p21 polymorphism with lung cancer risk in Taiwan. Lung cancer patients with Ser/Arg and Arg/Arg genotypes were at a nonsignificant 1.15-fold increased risk of lung cancer when compared to individuals with the Ser/Ser genotype (95%CI, 0.70-1.86). In addition, although p21 is a downstream target of p53, we found no significant correlation of the p21 polymorphism with the p53 polymorphism and p53 gene mutation in lung cancer patients. We further investigated the association of the p21 polymorphism with prognosis in 154 lung cancer patients. Patients with the Ser/Ser genotype tended to have a poorer prognosis than those with the Ser/Arg and Arg/Arg genotypes (P=0.097, by the log rank test). Our data suggest that the p21 codon 31 polymorphism may not play a significant role in cancer susceptibility and the prognosis of lung cancer patients in Taiwan.

Adenocarcinoma↗
PubMed2000

Bacteriology of infected cavitating lung tumor.

Differentiation between in situ infection and simple tumor necrosis in cavitating lung tumors by means of imaging studies is difficult. In this study, we prospectively investigated the role of ultrasound (US)-guided transthoracic aspiration for bacteriologic examination of infected cavitating lung tumors, and the influence of the culture results on the treatment of patients. Twenty-two patients (18 men and four women) with cavitating lung tumors treated from January 1996 to October 1998 were included. All patients underwent US-guided transthoracic aspiration for bacterial, fungal, and mycobacterial cultures. Microorganisms were isolated from six of seven febrile patients and one of 15 nonfebrile patients. A total of nine pathogens were isolated from seven patients: Klebsiella pneumoniae (n = 3); Haemophilus influenzae (n = 2); Enterococcus faecium (n = 1); Bifidobacterium (n = 1); Shewanella putrefaciens (n = 1); and Mycobacterium tuberculosis (n = 1). Two pathogens were isolated from the aspirate cultures in two patients, while the others had monomicrobial infection. The six febrile patients who had positive lung aspirate cultures were treated with empiric antimicrobial agents before the culture results were available, and the culture results led to adjustment of the antibiotic regimen in five of these. The clinical conditions of the six patients with infected cavitating lung tumors improved after the initiation of individualized antimicrobial treatment. Pneumothorax occurred in one patient, and was the sole procedure-related complication. In conclusion, US-guided transthoracic aspiration is helpful for differentiating infected cavitating lung tumors from simple tumor necrosis. Infection in cavitating lung tumors is common among febrile patients, and the culture results can guide modification of the antimicrobial therapy.

Aged↗
PubMed2000

Catamenial hemoptysis from tracheobronchial endometriosis: reappraisal of diagnostic value of bronchoscopy and bronchial brush cytology.

OBJECTIVES: To analyze the clinical data of four patients with a diagnosis of tracheobronchial endometriosis, and to reappraise the diagnostic value of bronchoscopy and bronchial brush cytology in these patients. METHODS: We conducted a retrospective study of four patients with documented tracheobronchial endometriosis treated at National Taiwan University Hospital from 1994 to 1998. The complete histories, diagnostic time interval, results of physical examinations, laboratory data, bronchoscopic findings, cytologic results, chest radiographs, and chest CT of these patients were analyzed. RESULTS: These patients tend to be younger and nonmultiparous as compared to other patients with thoracic endometriosis. Bronchoscopic examination performed within 1 day or 2 days of menses disclosed multiple purplish-red submucosal patches bilaterally that bled easily when touched. Cytologic evaluation of the brushing specimens demonstrated clusters of small cuboid cells consistent with an endometrial origin. Follow-up bronchoscopic examination in the middle of the menstrual cycle showed disappearance of the previous tracheobronchial lesions. The mean diagnostic interval was 3.25 months. All four patients were successfully treated with danazol therapy. CONCLUSIONS: Tracheobronchial endometriosis consists of a special subgroup of patients with thoracic endometriosis. Proper timing of bronchoscopic examination plays an important diagnostic role in these patients. Cytologic features as well as cyclic changes in bronchoscopic findings are sufficient to warrant the diagnosis. The results of treatment with danazol in these patients seemed favorable.

Adult↗
PubMed2000

Sonographic septation: a useful prognostic indicator of acute thoracic empyema.

The aim of this study was to identify sonographic predictors of patient outcomes or need for surgical intervention of acute thoracic empyema. All patients with a clinical diagnosis of thoracic empyema underwent transthoracic ultrasonographic examination and thoracentesis at admission. According to the presence or absence of septa in sonographic images, the patients were classified into two groups: septated and nonseptated. Sonographic findings were analyzed with respect to duration of hospital stay, chest tube drainage, and treatment efficacy. A total of 163 consecutive patients were included in the study (83 patients with septated and 80 with nonseptated sonographic images). The mean duration of hospital stay (35.4 versus 27.0 days, P = 0.009) and chest tube drainage (13.1 versus 7.6 days, P < 0.001) for the patients with septa were significantly longer than for those without septa. The patients with septa were more likely to undergo intrapleural fibrinolytic therapy (63.8% versus 38.8%, odds ratio 2.79, P = 0.001) and surgical intervention (24.3% versus 7.5%, odds ratio 3.92, P = 0.004). We concluded that sonographic septation is a useful sign to predict the need for subsequent intrapleural fibrinolytic therapy and surgical intervention in cases of acute thoracic empyema. Early fibrinolytic therapy or even surgical intervention may be indicated in patients with sonographic septations.

Acute Disease↗