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W H Hsu

Publications and source records attributed to W H Hsu.

At least 91 records · Page 5Linked to original sources
PubMed1995

The caffeine- and ryanodine-sensitive Ca++ store in porcine myometrial cells: its heterogeneity of all-or-none Ca++ release.

The mechanisms for Ca++ release from caffeine-sensitive stores were investigated in freshly dispersed porcine myometrial cells utilizing the fura-2 method. Because the caffeine-sensitive Ca++ store has not been detected in myometrium of mammals, we first determined the existence of this type of store in porcine myometrial cells. The evidence includes: 1) caffeine (1-33 mM)-induced concentration-dependent increase in the intracellular Ca++ concentration ([Ca++]i) in both the presence and absence of extracellular Ca++ and 2) although ryanodine alone (< or = 10 microM) failed to change [Ca++]i, it inhibited the response to caffeine in a use-, concentration- and time-dependent manner. In the cell suspension study, the amount of Ca++ released by 10 mM caffeine was found to be inversely proportional to the amount released by preadministration of caffeine (1-33 mM). In the single cell study, about 30% of cells responded to only a certain concentration of caffeine and the others responded to caffeine gradually. Thapsigargin, an inhibitor of Ca(++)-adenosine triphosphatase in sarcoplasmic reticulum, failed to increase [Ca++]i. Pretreatment with thapsigargin inhibited the response to caffeine in a time- and concentration-dependent manner. These results suggest that in porcine myometrial cells: 1) the Ca++ released from the caffeine- and ryanodine-sensitive store is in an all-or-none manner through compartments of stores or the entire store of a cell and 2) the release process is regulated by luminal Ca++ content of the stores.

Animals↗
PubMed1994

Influence of the formamidine pesticide amitraz and its metabolites on porcine myometrial contractility: involvement of alpha 2-adrenoceptors and Ca2+ channels.

Isolated uterine strips were used to study the effects of amitraz and its metabolites on porcine myometrial contractility during the luteal phase of the estrous cycle. Amitraz and its active metabolite BTS27271 (10(-8)-10(-5) M) caused a dose-dependent increase in myometrial contractility in the luteal phase strips, and BTS27271 was more efficacious than amitraz in this aspect. The other metabolites of amitraz at < or = 10(-4) M did not affect porcine myometrial contractility. The alpha 2-adrenoceptor antagonist, yohimbine (10(-8) -3 x 10(-7) M), but not the alpha 1-adrenoceptor antagonist, prazosin (10(-6) M), blocked the effect of amitraz and BTS27271 in a dose-dependent manner. When uterine strips were pretreated with the Ca(2+)-free Tyrode's solution or the voltage-dependent Ca2+ channel blocker verapamil (3 x 10(-5) M), the contractile effects of amitraz and BTS27271 were completely abolished, whereas those of carbachol were reduced. The results suggested that the amitraz- and BTS27271-induced myometrial contractions are mediated by alpha 2-adrenoceptors and this effect is mediated by an increase in extracellular Ca2+ influx through voltage-dependent Ca2+ channels.

Amidines↗
PubMed1994

Synonymy of Candida methylica with Candida boidinii and of Candida methanolophaga with Candida succiphila.

Some Candida species which can use methanol as a sole carbon source were studied by performing chemotaxonomic tests; we determined the ubiquinone systems of these organisms, their DNA base compositions, their electrophoretic karyotypes, and their DNA relatedness values. The type strains of Candida methanolophaga and Candida succiphila had similar DNA base compositions and exhibited 90% DNA relatedness. All Candida boidinii and Candida methylica strains had DNA G + C contents of 30.8 to 31.0 mol%, and these organisms exhibited 87 to 101% DNA relatedness to the type strain of C. boidinii. We propose that C. methanolophaga and C. methylica should be synonyms of C. succiphila and C. boidinii, respectively.

Base Composition↗
PubMed1994

Use of quantitative CT to predict postoperative lung function in patients with lung cancer.

PURPOSE: To evaluate the effectiveness of quantitative computed tomography (CT) for predicting postoperative lung function in patients with lung cancer. MATERIALS AND METHODS: Preoperative spirometry and conventional CT of the chest were performed in 38 patients. A postprocessing CT program was applied to quantitate the volume of whole-lung parenchyma with attenuations of -500 to -910 HU; this was defined as total functional lung volume (TFLV). The regional functional lung volume (RFLV) of the lobes or lung to be resected was quantitated separately. CT-predicted postoperative forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) were derived by multiplying the preoperative spirometry values by (1 - RFLV/TFLV). RESULTS: CT-predicted values correlated well with postoperatively measured results (FEV1: r = .93, P < .001; FVC: r = .86, P < .001) in patients who underwent pneumonectomy or lobectomy, regardless of the patient's preoperative ventilation status. CONCLUSION: This method is effective in the prediction of postoperative FEV1 and FVC in patients undergoing pulmonary resection.

Aged↗
PubMed1994

Characterization of freshly dispersed porcine myometrial cells: evidence for voltage-dependent Ca2+ channels and regulatory receptors.

A patch-clamp study of Ca2+ currents and spectrofluorometric detection of the intracellular Ca2+ concentration [Ca2+]i was performed on porcine myometrial cells that had been isolated by collagenase. Isolated myometrial cells were the typical long cylinder shape. The main length and diameter of myometrial cells were 505 +/- 20 and 11 +/- 0.5 microns (n = 40), respectively, in the prepartum period and 265 +/- 22 and 7 +/- 0.4 microns (n = 40), respectively, in the luteal phase. Immunocytochemistry with an antibody against desmin stained 90% of the cells positively, and about 95% of the cells excluded Trypan blue dye. The basal [Ca2+]i of myometrial cells in the luteal phase and the prepartum period was 119 +/- 12 (n = 30) and 154 +/- 31 nmol l-1 (n = 48), respectively. In prepartum myometrial cells, oxytocin (10(-7) mol l-1) and carbachol (10(-4) mol l-1) increased [Ca2+]i in a biphasic pattern, with a sharp peak followed by a plateau. In cells in the luteal phase, adrenaline (10(-7) mol l-1) plus propranolol (10(-6) mol l-1) produced a biphasic increase in [Ca2+]i. However, in the absence of propranolol, the increase in [Ca2+]i by adrenaline was small. Prostaglandin F2 alpha (10(-6) mol l-1) induced a monophasic increase in the [Ca2+]i in cells in the luteal phase. By depolarizing the cells from -30 to +50 mV from a holding potential of -50 mV, Ca2+ currents were evoked with a threshold at -20 mV, reaching a maximum between 10 and 30 mV.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Inhibition of insulin release by a formamidine pesticide amitraz and its metabolites in a rat beta-cell line: an action mediated by alpha-2 adrenoceptors, a GTP-binding protein and a decrease in cyclic AMP.

We tested the hypothesis that the formamidine pesticide amitraz and its metabolites inhibit insulin release from a rat beta-cell line (RINm5F) by decreasing intracellular cyclic AMP levels and examined whether GTP-binding proteins were involved in the process. Amitraz and its active metabolite BTS27271 (0.1-10 microM) inhibited insulin release that was induced by 100 microM of IBMX in a dose-dependent manner. Other metabolites of amitraz tested failed to inhibit insulin release. A potent and specific alpha-2 adrenoceptor agonist, medetomidine (0.1 microM), abolished the IBMX-induced insulin release. Amitraz, BTS27271 and medetomidine also decreased intracellular cyclic AMP concentrations that were elevated by IBMX administration. Moreover, all three drugs inhibited the insulin release stimulated by forskolin (1 microM), an adenylyl cyclase activator. Yohimbine (0.01, 0.1 and 1 microM), an alpha-2 adrenoceptor antagonist, prevented the inhibitory effect of amitraz and BTS27271 on insulin release, whereas prazosin (1 microM), an alpha-1 adrenoceptor antagonist, did not. Yohimbine, but not prazosin, also prevented the effect of amitraz, BTS27271 and medetomidine on IBMX-stimulated accumulation of cyclic AMP. Pretreatment of cells with PTX (0.1 micrograms/ml) for 16 h, antagonized the effects of amitraz and BTS27271 on IBMX-induced increase in insulin release. Thus, one mechanism by which amitraz and its metabolite BTS27271 decrease insulin release is by inhibiting adenylyl cyclase, an action mediated through a PTX-sensitive G-protein.

1-Methyl-3-isobutylxanthine↗
PubMed1994

Ultrasound-guided biopsy of thoracic masses.

BACKGROUND: Fine needle aspiration cytologic examination may be sufficient for managing patients with primary lung cancer. However, the procedure is not reliable for benign lesions and metastatic lung cancers. An attempt was made to find the influence of cell type on the results of fine needle aspiration and cutting biopsy. METHODS: One hundred and sixteen patients with thoracic nodules or masses underwent chest ultrasound examination and percutaneous ultrasound-guided needle biopsy. All patients underwent ultrasound-guided fine needle aspiration biopsy (UGAB) and thirty-eight of them also underwent ultrasound-guided cutting biopsy (UGCB). Thoracic lesions were divided into seven groups. RESULTS: Using UGAB alone, the diagnostic rate varied from 56% (mediastinal tumor) to 91% (lung mass). When both methods of UGAB and UGCB were evaluated, the diagnostic rate varied from 67% (pulmonary nodule) to 100% (collapsed lung with mass and pancoast tumor). When thoracic lesions were divided into carcinomatous neoplasms (n = 88) and noncarcinomatous lesions (n = 21), a higher diagnostic rate was found in the carcinomatous group than in the noncarcinomatous group (92% versus 53%, p < 0.001). Correct histologic results between both groups had no statistical significance (64% versus 56%, p > 0.05). CONCLUSIONS: Ultrasound-guided needle biopsy has a high diagnostic yield of thoracic tumors, and carcinomatous masses can be easily diagnosed by UGCB. Noncarcinomatous masses and benign tumors frequently need UGAB to obtain a histologic diagnosis.

Adolescent↗
PubMed1994

Arginine vasopressin-stimulated insulin secretion and elevation of intracellular Ca++ concentration in rat insulinoma cells: influences of a phospholipase C inhibitor 1-[6-[[17 beta-methoxyestra-1,3,5(10)-trien- 17-yl]amino]hexyl]-1H-pyrrole-2,5-dione (U-73122) and a phospholipase A2 inhibitor N-(p-amylcinnamoyl)anthranilic acid.

The present study investigated the mechanism by which arginine vasopressin (AVP) increases insulin secretion in rat insulinoma (RINm5F) cells by using a specific phospholipase C (PLC) inhibitor, 1-[6-[[17 beta-3-methoxyestra-1,3,5(10)-trien-17- yl]amino]hexyl]-1H-pyrrole-2,5-dione (U-73122), and a phospholipase A2 (PLA2) inhibitor, N-(p-amylcinnamoyl)anthranilic acid (ACA). AVP (0.1-100 nM) increased insulin secretion and cytosolic free Ca++ concentration ([Ca++]i) dose-dependently. AVP-induced increases in the intracellular concentration of inositol 1,4,5-trisphosphate (IP3) and [Ca++]i were dose-dependently inhibited by U-73122 (2-8 microM). At 8 microM, U-73122 abolished AVP's effect on IP3 and [Ca++]i, but AVP-induced increases in insulin secretion were only reduced by 35%. In contrast, 8 microM U-73122 did not reduce the ionomycin (a Ca++ ionophore, 100 nM)-induced increase in [Ca++]i. The discrepancy between the results of [Ca++]i and insulin secretion in U-73122 experiments is indicative of the multiple signal transduction pathways associated with the activation of AVP receptors, specifically the Ca(++)-independent pathway. The phospholipase A2 inhibitor ACA (100 microM) did not antagonize AVP (10 nM)-induced increases in insulin secretion. These results suggested: 1) U-73122 blocks PLC activities but fails to block other signal transduction pathways that trigger insulin secretion in these cells and 2) AVP increases insulin release from RINm5F cells through both the PLC-mediated Ca(++)-dependent and Ca(++)-independent pathways.

Animals↗
PubMed1994

Carcinosarcoma of the lung: an analysis of 6 operated cases.

BACKGROUND: Carcinosarcoma of the lung is a rare malignant pulmonary neoplasm, and constitutes 0.1% to 0.3% of all lung tumors. Typically, these tumor have both carcinomatous and sarcomatous components with a poor prognosis due to late diagnosis and early metastases. METHODS: From July 1980 to December 1993, six patients with pulmonary carcinosarcoma who underwent surgical treatment were studied. None of them had accurate tissue diagnosis before operation except one case with peripheral variant carcinosarcoma who was diagnosed by percutaneous transthoracic fine needle biopsy under sonographic guidance. All of our patients had a huge peripheral lung tumor 3.8 to 10 cm in diameter. Pneumonectomy was done in two patients, and lobectomy in three. The other patient had unresectable tumor. RESULTS: The histopathological components in carcinoma were epidermoid carcinoma in and adenocarcinoma in 3. Differentiation of sarcomatous lesions included spindle cell sarcoma in 3, fibrosarcoma in 2 and undifferentiated mesenchymal sarcoma in one patient. In the resectable group, 1 was at stage II and 4 were at stage IIIa. None of the patients survived more than 2 years due to distant metastasis and cachexia. The mean survival was 140 days. CONCLUSIONS: The carcinomatous portion tends to metastasize to regional lymph nodes whereas the sarcomatous part gives rise to systemic dissemination. Due to early systemic dissemination and poor prognosis, combination of extensive surgical intervention resection with aggressive postoperative chemotherapy and radiotherapy might be a reasonable consideration to improve survival in primary pulmonary carcinosarcoma.

Adult↗
PubMed1994

Management for acute corrosive injury of upper gastrointestinal tract.

BACKGROUND: It is imperative that the surgeon promptly determine the severity of any acute injury of the upper gastrointestinal (UGI) tract by caustic material ingested and the definite therapy be instituted. Prognostic factors of such injuries have not been clearly demonstrated in previous reports. Here, some prognostic factors and recommended emergency surgical indications in clinical assessment are discussed. METHODS: Forty-six patients (22 men and 24 women; age range 19 to 77 years), sustaining acute corrosive injuries to the UGI tract, were retrospectively assessed from November 1990 to May 1993. Immediate management was given to prevent shock, to identify any associated injury and to observe patency of the airway. Emergency operation was performed if any signs of peritonitis, mediastinitis or sepsis were present. Age, sex, time interval between ingestion and initial resuscitation, consciousness, peritoneal sign, shock index, pH value and [HCO3-] in arterial blood gas were evaluated as prognostic factors with respect to mortality. Chi-square test with Yates' correction was used. A p value less than 0.05 was regarded as statistically significant. RESULTS: Suicide attempt by caustic ingestion was in 40 patients (87%) and ingestion was accidental in 6 (13%). Acidic injury was specified in 36 patients (78.3%). In 14 severely injured patients, emergency exploratory laparotomy with or without esophagogastrectomy was performed in 9 (19.6%), of whom 2 survived. The other five patients were treated conservatively, and all died. Overall mortality rate was 26.1% (12/46). A significantly higher mortality rate was observed in patients with age > or = 50 years, positive peritoneal sign, shock index > 1, pH below 7.2 and bicarbonate concentration below 16 mEq/L as revealed by arterial blood gas (p < 0.05). CONCLUSIONS: The prognostic factors related to a higher mortality rate included age 50 years old or more, positive peritoneal sign, shock index above 1, pH below 7.2 and [HCO3-] below 16 mEq/L in arterial blood gas. Recognition of these factors indicates further detailed study will be required to propose a caustic injury score for predicting severity. Nevertheless, emergency operation is recommended if there are positive signs of peritonitis or mediastinitis, shock index above 1, pH below 7.0 and [HCO3-] below 10 mEq/L in arterial blood gas.

Acute Disease↗
PubMed1993

The cloning and nucleotide sequence of a Corynebacterium glutamicum 3-deoxy-D-arabinoheptulosonate-7-phosphate synthase gene.

The aro gene of Corynebacterium glutamicum CCRC 18310 encoding 3-deoxy-D-arabinoheptulosonate-7-phosphate (DAHP) synthase was isolated by complementation of a DAHP synthase-deficient mutant of Escherichia coli AB3257. The specific activity of DAHP synthase was increased four-fold in a C. glutamicum strain harboring the cloned aro gene. The complete nucleotide sequence of the aro gene and its 5' and 3' flanking regions has been determined. The sequence contained an open reading frame of 368 codons, from which a protein with a molecular mass of 39,340 Da could be predicted. The deduced amino acid sequence shows high identity with the aro gene products of E. coli and Salmonella typhimurium.

3-Deoxy-7-Phosphoheptulonate Synthase↗
PubMed1993

Cloning and characterization of an alpha-amylase gene from Streptomyces lividans.

The alpha-amylase gene (amy) of Streptomyces lividans TK24 was cloned in an amylase deficient mutant strain S. lividans M2. The cloned gene contained an open reading frame (ORF) of 2757 nucleotides (919 amino acids) coding for a protein of 100 kDa. Sequencing of the amino terminus of the extracellular alpha-amylase protein revealed the presence of a signal peptide of 33 amino acid residues. The transcriptional initiation site was mapped by the primer extension method with T4 DNA polymerase and was found to be transcribed from an unique promoter. The alpha-amylase protein produced by S. lividans was larger than those derived from other origins. It also contained the four common conserved regions characteristic of other alpha-amylase proteins.

Amino Acid Sequence↗
PubMed1993

A paradoxical stimulatory effect of berberine on guinea-pig ileum contractility: possible involvement of acetylcholine release from the postganglionic parasympathetic nerve and cholinesterase inhibition.

The effects of berberine on guinea-pig ileum contractility were studied in both transmurally-stimulated and unstimulated preparations. Transmural stimulation (80 V, 0.5 ms, 0.05 Hz) of the guinea-pig ileal segments produced a twitch response. Berberine (10(-8)-10(-5) M) enhanced this response dose-dependently. Atropine (10(-7) M), but not mecamylamine (10(-5) M), abolished this response. Acetylcholine (3 x 10(-9) and 10(-8) M) also enhanced the response to transmural stimulation. Pretreatment with hemicholinium (3 x 10(-5) M) antagonized the effect of berberine but failed to change that of acetylcholine. Berberine (10(-5) M) also antagonized the alpha 2-adrenoceptor agonist xylazine (10(-8) and 10(-7) M)-induced inhibition of the twitch response to transmural stimulation. In unstimulated ileal preparations, berberine (10(-5) M) produced contractile responses. In these preparations, atropine (10(-6) M), but not mecamylamine (10(-4) M), abolished the response to berberine. Furthermore, berberine (10(-6)-10(-4) M) inhibited dose-dependently the cholinesterase activity of the guinea-pig blood. The results suggest that berberine increases ileal contractility by: 1) increasing acetylcholine release from the postganglionic parasympathetic nerve terminal, 2) increasing acetylcholine retention through an inhibition of cholinesterase activity, and 3) blocking alpha 2-adrenoceptors, possibly in the postganglionic parasympathetic nerve.

Acetylcholine↗
PubMed1993

Protein secondary structure modelling with probabilistic networks.

In this paper we study the performance of probabilistic networks in the context of protein sequence analysis in molecular biology. Specifically, we report the results of our initial experiments applying this framework to the problem of protein secondary structure prediction. One of the main advantages of the probabilistic approach we describe here is our ability to perform detailed experiments where we can experiment with different models. We can easily perform local substitutions (mutations) and measure (probabilistically) their effect on the global structure. Window-based methods do not support such experimentation as readily. Our method is efficient both during training and during prediction, which is important in order to be able to perform many experiments with different networks. We believe that probabilistic methods are comparable to other methods in prediction quality. In addition, the predictions generated by our methods have precise quantitative semantics which is not shared by other classification methods. Specifically, all the causal and statistical independence assumptions are made explicit in our networks thereby allowing biologists to study and experiment with different causal models in a convenient manner.

Algorithms↗
PubMed1993

Diagnostic value of pleural adenosine deaminase in tuberculous effusions of immunocompromised hosts.

To investigate the diagnostic value of adenosine deaminase (ADA) in immunocompromised hosts with tuberculous pleural effusions, we collected and checked 60 pleural effusion specimens from admitted patients. These patients were divided into three groups: group I (n = 20), immunocompetent hosts with tuberculous pleural effusions; group II (n = 10), immunocompromised hosts with tuberculous pleural effusions; and group III (n = 30), patients with malignant pleural effusions. Using statistical analysis to compare the ADA value in each group, the p value was found to be significant between groups I and II (p < 0.01), groups I and III (p < 0.001) and groups I+II and III (p < 0.001); however, the p value was not significant between groups II and III. If the lowest ADA value for the tuberculous pleural effusion was designed as 80 U/L, the sensitivity/specificity was 1.0/0.90 (group I), 0.40/0.90 (group II), and 0.80/0.90 (group I+II), respectively. We conclude that the diagnostic value of ADA in immunocompromised hosts with tuberculous pleural effusions is not as significant as in immunocompetent hosts.

Adenosine Deaminase↗
PubMed1993

Apical malignancies diagnosed by ultrasound-guided fine needle aspiration biopsy.

Sixteen patients with apical malignancies, including 12 with Pancoast tumors and four with metastatic apical pleural masses, underwent chest ultrasound (US) examinations and direct percutaneous fine needle aspiration biopsy (FNAB). Of those, 15 patients were proven to have malignancies by FNAB and the remaining patient (only revealing necrosis by FNAB) was also proven to have a Pancoast tumor after surgical intervention. Percutaneous FNAB was performed through the supraclavicular approach (n = 10) or through the upper back (n = 6). The sonographic appearances of the apical malignancies were homogeneous hypoechoic (n = 8), homogeneous isoechoic (n = 3) or heterogeneous (n = 5). No complications occurred after the FNAB. Our limited experience showed that a convex probe was convenient and useful in the detection of apical malignancies. Apical malignancies, diagnosed previously by percutaneous needle aspiration under fluoroscopy or surgical intervention, can be easily diagnosed by percutaneous FNAB, especially when the FNAB is performed using the supraclavicular approach.

Aged↗
PubMed1992

Impalpable thoracic bony lesions diagnosed by sonographically guided needle aspiration biopsy.

Impalpable osteolytic lesions may be detected and diagnosed by ultrasonography and sonographically guided needle aspiration biopsy. Eleven cases with bone destruction found on chest radiographs were proved to be malignant by sonographically guided needle aspiration biopsy. The bony lesions were all hypoechoic and could be demonstrated easily. No complications or discomfort occurred after needle aspiration. Bony lesions can be detected by ultrasonography only when pathologic changes have occurred. Ultrasonography and sonographically guided needle aspiration biopsy provide a simple, convenient, and non-invasive method for detecting and diagnosing impalpable osteolytic lesions.

Aged↗