Biomedical subjects

W H Hsu

Publications and source records attributed to W H Hsu.

At least 37 records · Page 2Linked to original sources

PubMed2000

Resectional treatment for thyroid cancer with tracheal invasion: a long-term follow-up study.

HYPOTHESIS: Transmural invasion of the trachea by well-differentiated thyroid carcinomas is a locally advanced disease condition. It frequently causes deaths owing to airway obstruction. We hypothesized that resection of the invaded trachea followed by primary anastomosis provides the opportunity for cure. DESIGN: A retrospective review study of medical records. SETTING: The surgical department of a tertiary referral center. PATIENTS: Eight patients with well-differentiated thyroid carcinomas, complicated with tracheal invasion resulting in bleeding and airway obstruction, operated on by tracheal resection and immediate anastomosis, were included. INTERVENTIONS: All patients received total thyroidectomy and neck lymph node dissection as well as segmental tracheal resection followed by primary reconstruction. Postoperative radioactive sodium iodine I 131 treatment and suppression therapy with thyroxine were applied to all of them. MAIN OUTCOME MEASURE: Postoperative follow-up of serum levels of human thyroglobulin and abnormal radioactive iodine 131I from whole body scan. RESULTS: Seven patients are alive. Of these patients, 5 had no evidence of disease: (3 had no evidence of cancer for more than 10 years' follow-up), 2 had regional lymph node metastasis, and 1 had lung metastases. The remaining patient had anastomotic site recurrence with airway obstruction and needed tracheostomy to relieve stridor. She was lost to follow-up 39 months after undergoing the initial operation. CONCLUSIONS: Patients with mucosal invasion of the trachea by well-differentiated thyroid carcinomas should be treated by surgical resection followed by primary reconstruction when technically feasible. This facilitates postoperative care, and it is possible to achieve long-term survival with improvement of the quality of life and possible cures.

Adult↗

PubMed2000

Mechanisms of AVP-induced glucagon release in clonal alpha-cells in-R1-G9: involvement of Ca(2+)-dependent and -independent pathways.

1. The mechanisms underlying AVP-induced increase in [Ca(2+)](i) and glucagon release in clonal alpha-cells In-R1-G9 were investigated. 2. AVP increased [Ca(2+)](i) and glucagon release in a concentration-dependent manner. After the administration of AVP, glucagon was released within 30 s, quickly reached the maximum within 2 min, and maintained a steady-state concentration for at least 15 min. 3. In Ca(2+)-containing medium, AVP increased [Ca(2+)](i) in a biphasic pattern; a peak followed by a sustained plateau. In Ca(2+)-free medium, the Ca(2+) response to AVP became monophasic with lower amplitude and no plateau. Both the basal and AVP-induced glucagon releases were lower in the absence than in the presence of extracellular Ca(2+). When [Ca(2+)](i) was stringently deprived by BAPTA, a Ca(2+) chelator, AVP still significantly increased glucagon release. 4. Pretreatment with thapsigargin, a microsomal Ca(2+) ATPase inhibitor, abolished both the Ca(2+) peak and sustained plateau. 5.AVP increased intracellular concentration of IP(3). 6. U-73122 (8 microM), a phospholipase C inhibitor, abolished AVP-induced increases in [Ca(2+)](i), but only reduced AVP-induced glucagon release by 39%. 7. Pretreatment with nimodipine, an L-type Ca(2+) channel blocker failed to alter AVP-induced glucagon release or increase in [Ca(2+)](i). 8. The results suggest that AVP causes glucagon release through both Ca(2+)-dependent and -independent pathways. For the Ca(2+)-dependent pathway, the G(q) protein activates phospholipase C, which catalyzes the formation of IP(3). IP(3) induces Ca(2+) release from the endoplasmic reticulum, which, in turn, triggers Ca(2+) influx. Both Ca(2+) release and Ca(2+) influx may contribute to AVP-induced glucagon release.

Amino Acid Chloromethyl Ketones↗

PubMed2000

Efficient utilization of starch by a recombinant strain of Saccharomyces cerevisiae producing glucoamylase and isoamylase.

Two plasmids, designated pRTI and pTI, were constructed to allow the integration of a bacterial isoamylase gene (iso) into Saccharomyces cerevisiae G23-8 chromosome. The integrative plasmid pRTI comprises the iso gene from Pseudomonas amyloderamosa, a portion of S. cerevisiae ribosomal DNA (rDNA), S. cerevisiae trp1 gene deficient in promoter and the bacterial vector pSP72. The structure of plasmid pTI is similar to that of pRTI, except that it lacks an rDNA segment. The Aspergillus awamori glucoamylase and P. amyloderamosa isoamylase genes were expressed in the recombinant strain of S. cerevisiae under the control of the yeast alcohol dehydrogenase gene (adh1) promoter. Southern-blot analysis showed that these plasmids were integrated into the yeast chromosome in tandem repeat and dispersion copies. The recombinant strains could assimilate starch more efficiently than the recipient strain with a conversion rate of greater than 95%.

Chromosomes, Fungal↗

PubMed2000

Stimulatory effect of bradykinin (BK) on glucagon secretion from the perfused rat pancreas: involvement of BK2 receptors.

The purpose of the study is to investigate the direct effect of bradykinin (BK), a potent vasoactive nonapeptide, on glucagon secretion from the perfused rat pancreas. BK (0.1, 1, and 10 micromol/L) increased glucagon secretion in a concentration-dependent manner. HOE 140, a BK2 receptor antagonist (0.01, 0.1, and 1 nmol/L), prevented the stimulatory effect of BK on glucagon secretion in a concentration-dependent manner. In contrast, des-Arg9,Leu8-BK, a BK1 receptor antagonist (1 nmol/L), failed to antagonize the effect of BK. Thus, BK stimulates glucagon secretion from the perfused rat pancreas by activating BK2 receptors, but not BK1 receptors.

Animals↗

PubMed2000

Squamous cell carcinoma of the right upper lung congenital tracheal bronchus.

Tracheal bronchus, directly arising from the abnormal tracheal wall, is a rare congenital anomaly of the airway. Lung cancer developing in a tracheal bronchus is even more rare. A 68-year-old man had a mass shadow over the right upper lung on chest radiography. Bronchoscopy revealed an abnormally displaced bronchus stemming from the right side of the tracheal wall, 2 cm above the carina. Arising from this tracheal bronchus was a tumor, a biopsy of which showed squamous cell carcinoma. During surgery, a bronchus arising from the right lateral wall of the trachea and supplying the apical segment of the right upper lobe was found. There was a tumor occluding the lumen of the tracheal bronchus, causing distal obstructive pneumonitis. The patient underwent right upper lobectomy with closure of the tracheal bronchus and radical lymph node dissection. The subsequent pathologic examination of the specimen revealed squamous cell carcinoma with surrounding pneumonitis. Bronchogenic cancers developing in a tracheal bronchus are rarely reported in the English language literature. Surgical resection appears to be the treatment of choice.

Bronchi↗

PubMed2000

Indolent cutaneous mucormycosis with pulmonary dissemination in an asthmatic patient: survival after local debridement and amphotericin B therapy.

We describe a 68-year-old asthmatic female patient with multiple pulmonary cavities. A preexisting ecthyma on the left lower leg became erythematous and swollen during exacerbation of her asthma which was under treatment with high-dose steroids. Nonseptate broad hyphae were found in her sputum, pus from the wound, and debrided skin tissue. Hematogenous spread of septic emboli from indolent cutaneous mucormycosis to both lungs was the suspected mechanism of dissemination. High-dose steroid therapy may have been the major contributory factor. The patient was successfully treated with local surgical debridement of the wound and intravenous amphotericin B.

Aged↗

PubMed1999

Development of rabbit embryos during a 96-h period of in vitro culture after superovulatory treatment under conditions of elevated ambient temperature.

The effects of elevated ambient temperature on the response to exogenous gonadotropins were evaluated in female New Zealand White rabbits exposed to 33+/-1 degrees C (mean +/- SE) and 10-30% relative humidity (8 h/day) during a 5-day period. Does were treated with pFSH (0.3 mg/0.3 ml Standard Armour) twice daily during three consecutive days with a minimum interval of 8 h between injections. Six hours after the last FSH injection all does were removed from the experimental chamber, given hCG (25 IU/kg) and paired overnight. Nineteen hours after pairing, embryos were flushed from the reproductive tracts, evaluated, and subjected to in vitro culture during a 96-h period. The ovulatory responses to exogenous gonadotropins and fertilization rates did not differ significantly under conditions of elevated ambient temperature, whereas fewer blastocysts and increased number of degenerate embryos were observed after culture. We conclude that although hyperthermia was induced during exposure to elevated ambient temperature, it did not alter the ovulatory responses to gonadotropin treatment and plasma concentrations of FSH and LH compared with does in a thermoneutral environment. Exposure of donor rabbits to elevated ambient temperature before mating, however, increased embryonic degeneration.

Animals↗

PubMed1999

The role of a conserved histidine residue, His324, in Trigonopsis variabilis D-amino acid oxidase.

To investigate the functional role of an invariant histidine residue in Trigonopsis variabilis D-amino acid oxidase (DAAO), a set of mutant enzymes with replacement of the histidine residue at position 324 was constructed and their enzymatic properties were examined. Wild-type and mutant enzymes have been purified to homogeneity using the His-bound column and the molecular masses were determined to be 39.2 kDa. Western blot analysis revealed that the in vivo synthesized mutant enzymes are immuno-identical with that of the wild-type DAAO. The His324Asn and His324Gln mutants displayed comparable enzymatic activity to that of the wild-type enzyme, while the other mutant DAAOs showed markedly decreased or no detectable activity. The mutants, His324/Asn/Gln/Ala/Tyr/Glu, exhibited 38-181% increase in Km and a 2-10-fold reduction in kcat/Km. Based on the crystal structure of a homologous protein, pig kidney DAAO, it is suggested that His324 might play a structural role for proper catalytic function of T. variabilis DAAO.

Amino Acid Sequence↗

PubMed1999

Effects of the pesticide amitraz and its metabolite BTS 27271 on insulin and glucagon secretion from the perfused rat pancreas: involvement of alpha2D-adrenergic receptors.

The study purpose was to investigate the direct effect of amitraz, a formamidine insecticide/acaricide, and its active metabolite BTS 27271 on insulin and glucagon secretion from the perfused rat pancreas. Amitraz and BTS 27271 (0.01, 0.1, 1, and 10 micromol/L) inhibited insulin secretion in a concentration-dependent manner. Amitraz increased glucagon secretion at 10 micromol/L, whereas BTS 27271 increased glucagon secretion at 1 and 10 micromol/L. Amitraz- and BTS 27271-induced decreases in insulin secretion and increases in glucagon secretion were not abolished during the 10-minute washout period. During the arginine treatment, both amitraz and BTS 27271 groups (0.1, 1, and 10 micromol/L) had lower insulin secretion and higher glucagon secretion than the control group. Idazoxan, an alpha2A/2D-adrenergic receptor (AR) antagonist, prevented the inhibitory effect of amitraz on insulin secretion in a concentration-dependent manner, but prazosin, an alpha1- and alpha2B/2C-AR antagonist, failed to antagonize the effect of amitraz. These results demonstrate that (1) amitraz and BTS 27271 inhibit insulin and stimulate glucagon secretion from the perfused rat pancreas, (2) amitraz inhibits insulin secretion by activation of alpha2D-ARs, since rats have alpha2D- but not alpha2A-ARs, and (3) amitraz and BTS 27271 may have a high binding affinity to the alpha2D-ARs of pancreatic islets.

Adrenergic alpha-Agonists↗

PubMed1999

Expression, crystallization and preliminary X-ray diffraction studies of N-carbamyl-D-amino-acid amidohydrolase from Agrobacterium radiobacter.

The Agrobacterium radiobacter CCRC 14924 N-carbamyl-D-amino-acid amidohydrolase, the enzyme used for production of D-amino acids, was overexpressed in Escherichia coli JM109. The expressed protein was crystallized by vapour diffusion using lithium sulfate as precipitant. It crystallizes in space group P21 with unit-cell parameters a = 69.8, b = 67.9 and c = 137.8 A and beta = 96.4 degrees. There are four molecules per asymmetric unit. Crystals diffract to 2.8 A resolution using a rotating-anode source at cryogenic (113 K) temperatures.

Amidohydrolases↗

PubMed1999

Characterization of receptors mediating AVP- and OT-induced glucagon release from the rat pancreas.

We characterized the receptors that mediate arginine vasopressin (AVP)- and oxytocin (OT)-induced glucagon release by use of a number of antagonists in the perfused rat pancreas and the fluorescence imaging of the receptors. AVP and OT (3 pM-3 nM) increased glucagon release in a concentration-dependent manner. The antagonist with potent V(1b) receptor-blocking activity, CL-4-84 (10 nM), abolished AVP (30 pM)-induced glucagon release but did not alter OT (30 pM)-induced glucagon release. d(CH(2))(5)[Tyr(Me)(2)]AVP (10 nM), a V(1a) receptor antagonist, and L-366,948 (10 nM), a highly specific OT-receptor antagonist, failed to inhibit AVP-induced glucagon release. In contrast, L-366,948 (10 nM) abolished OT (30 pM)-induced glucagon release but did not change the effect of AVP. Fluorescent microscopy of rat pancreatic sections showed that fluorescence-labeled AVP and OT bound to their receptors in the islets of Langerhans and that the bindings were inhibited by 1 microM of Cl-4-84 and L-366,948, respectively. Because AVP and OT at physiological concentrations (3-30 pM) increased glucagon release, we conclude that AVP and OT increase glucagon release under the physiological condition through the activation of V(1b) and OT receptors, respectively.

Animals↗

PubMed1999

Traumatic diaphragmatic hernia with delayed presentation.

BACKGROUND: Traumatic diaphragmatic rupture may occur in patients with thoracoabdominal injuries, and still poses a diagnostic challenge to surgeons. Those patients who survive the events without being diagnosed in the acute phase develop chronic traumatic diaphragmatic hernia. In this study, we reviewed cases of chronic traumatic diaphragmatic hernia managed over the past 35 years. METHODS: We retrospectively evaluated the clinical courses and radiologic images of 24 cases with chronic traumatic diaphragmatic hernia. RESULTS: Motor vehicle accident with blunt abdominal trauma was the most important mode of injury. Herniation was more common to the left plural cavity than to the right. The interval between injury and the onset of symptoms ranged from two weeks to 40 years (average, 7.3 years). Vague chest pain, shortness of breath, and bowel obstruction are the most common presentations. Chest radiographic findings suggested the diagnosis of diaphragmatic hernia in 20 patients. Barium study of the gastrointestinal tract was required to confirm the diagnosis. The most common herniated abdominal viscera were the stomach and colon. All patients received thoracotomy with reduction of hernia organs and closure of the diaphragmatic defect. The hospital course was uneventful with no operative mortality. CONCLUSIONS: Careful interpretation of radiographic images and early surgical intervention are essential in the management of patients with chronic traumatic diaphragmatic hernia. Thoracotomy with reduction of herniated organs can be performed safely with satisfactory results.

Adolescent↗

PubMed1999

Leiomyosarcoma of the gastric cardia and fundus.

BACKGROUND: Gastric leiomyosarcoma is rare among gastric malignancies, and only 20% of the cases are located in the gastric cardia or fundus. It has clinical manifestations different from tumors in other sites of the stomach. We reviewed cases of leiomyosarcoma of the gastric cardia or fundus to evaluate their clinicopathologic characters and patient survival. METHODS: From May, 1981, to June, 1998, a total of 15 patients who underwent curative resection of leiomyosarcoma of the gastric cardia or fundus were retrospectively identified and studied. All the clinical and pathologic data were reviewed and recorded. RESULTS: There were 11 men and four women. Their mean age was 59.1 years (range, 37-73 years). Tarry stools and epigastric fullness and pain were the most common symptoms, followed by body weight loss. All 15 patients had submucosal tumors in the gastric cardia or fundus, as shown by endoscopy, barium contrast radiography and computerized tomography. The incidence of esophageal involvement by the tumors was quite low. The mean tumor size was 10 cm, ranging from 4 cm to 20 cm. Locoregional organs were involved in nine patients. The median and mean survivals were 17.8 months and 31.7 months, respectively (range, 10.1-80.1 months) after curative resection. The three-year and five-year survival rates were 53% and 22%, respectively. CONCLUSIONS: The definitive preoperative diagnosis of the tumor is difficult before surgery, even though imaging studies show positive findings. Surgical resection with an adequate safe margin of normal tissue is the treatment of choice. Tumor size, serosal invasion with locoregional organ involvement and high tumor grade were the prognostic factors in the study.

Adult↗

PubMed1998

A conserved aspartate is essential for FAD binding and catalysis in the D-amino acid oxidase from Trigonopsis variabilis.

To evaluate the possible contribution of Asp206 of Trigonopsis variabilis D-amino acid oxidase (DAO) to its flavin adenine dinucleotide (FAD) binding and catalytic function, six mutant enzymes were constructed by site-directed mutagenesis. Western immunoblot analysis revealed that a protein with an apparent molecular mass of about 39.2 kDa was present in the cell-free extracts of wild-type and mutant strains. Replacement of Asp206 with Leu, Gly, and Asn resulted in the loss of DAO activity and characteristic absorption spectrum for flavoenzyme, while the other mutant DAOs, Asp206Glu, Asp206Ser, and Asp206Ala, exhibited a similar spectral profile to that of wild-type enzyme and retained about 6-90% of the enzyme activity. These results suggested that Asp206 of T. variahilis DAO might play an important role in the binding of FAD.

Amino Acid Sequence↗

PubMed1998

Identification of the open reading frame for the Pseudomonas putida D-hydantoinase gene and expression of the gene in Escherichia coli.

A DNA fragment containing the gene for D-hydantoinase was cloned from Pseudomonas putida CCRC 12857 into Escherichia coli. The cloned gene contained an open reading frame (ORF) of 1485 nucleotides encoding a protein of 53.4 kDa in which the carboxyl terminal end is longer than that previously deduced from strain DSM 84. This ORF was verified by amino acid sequencing of amino and carboxyl termini, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and amino acid sequence comparison. Deletion analysis revealed that 32 amino acids from the carboxyl terminal end were essential for D-hydantoinase activity. Tagging of six consecutive histidyl residues to the amino terminus or to the carboxyl terminus of the enzyme did not significantly affect D-hydantoinase activity. Under the control of T5lac promoter and lactose induction, the D-hydantoinase activity of transformed E. coli reached 200 U l-1 which is about 20-fold higher than that of gene donor strain.

Amidohydrolases↗

PubMed1998

Metabolic detriment in donor heart valves induced by ischemia and cryopreservation.

BACKGROUND: The injury resulting from postmortem ischemia is a critical deterrent to the availability of donor valves. Using the reduction of XTT-tetrazolium salt as a marker of metabolic sequelae, we assessed the injurious effect of ischemia and the metabolic sequelae in 156 porcine semilunar leaflets. METHODS: The leaflets were randomly allocated to noncryoprocessed (n = 72) or cryoprocessed (n = 72) groups. At each preservation temperature of 4 degrees C, 24 degrees C, or 37 degrees C, 24 leaflets each were exposed to one of four storage periods of 9, 17, 30, or 60 hours. Twelve fresh aortic leaflets served as baseline reference samples. RESULTS: There was a progressive loss in the metabolic functioning of valve leaflet cells in both noncryopreserved and cryopreserved tissue as the storage times increased. Cryopreserved tissue showed a greater loss of function than noncryopreserved tissue did. The metabolic injury was mainly a consequence of cryoprocessing. The greatest loss in metabolic functioning occurred in the valves stored for 60 hours. The least favorable combination of variables was cryopreservation and a precryopreservation storage time of 60 hours. CONCLUSIONS: We conclude that 30- to 60-hour delays do not have a significant metabolic effect on cardiac leaflets. Thus it may be possible to safely extend the permissible ischemic periods after organ harvest.

Animals↗

PubMed1998

Effects of arginine vasopressin and oxytocin on glucagon release from clonal alpha-cell line In-R1-G9: involvement of V1b receptors.

Receptor antagonists were used to determine which receptor mediates the effect of arginine vasopressin (AVP) and oxytocin (OT) on glucagon release from hamster glucagonoma In-R1-G9 cells. Both AVP (10(-9)-10(-6) M) and OT (10(-8)-10(-5) M) increased glucagon release from In-R1-G9 cells in a concentration-dependent manner and AVP was approximately 30-fold more potent than OT in this aspect. The antagonists with potent V1b receptor blocking activity, CL-4-84 (10(-9)-10(-6) M), dP[Tyr(Me)2]AVP and AO-2-44 (10(-8)-10(-6) M), antagonized the effect of both AVP and OT in a concentration-dependent manner. Other receptor antagonists at 10(-6) M failed to block the effect of AVP and OT; these included a highly selective OT-receptor antagonist, L-366,948 and a V1a/V2 receptor antagonist WK-3-6. However, these antagonists at higher concentrations (10(-5) and 10(-4) M) caused inhibition of AVP- and OT-induced glucagon release. The order of antagonistic potency was estimated as CL-4-84 approximately = dP[Tyr(Me)2]AVP approximately = AO-2-44 > WK 3-6 > L366,948. d[D-3-Pal]VP (10(-8)-10(-5) M), a V1b receptor agonist, also increased glucagon release in a concentration-dependent manner, which was antagonized by dP[Tyr(Me)2]AVP (10(-8)-10(-6) M) and CL-4-84 (10(-9)-10(-6) M), but not by WK-3-6 (10(-6) M) or L-366,948 (10(-6) M). Therefore, the stimulatory effects of both OT and AVP on glucagon release may be mediated by V1b receptors, but not by V1a, V2, or OT receptors.

Animals↗

PubMed1998

Color Doppler ultrasound pulsatile flow signals of thoracic lesions: comparison of lung cancers and benign lesions.

Color Doppler ultrasound (US) was performed in 153 patients (including 102 with lung cancer and 51 with benign lesions) to assess pulsatile flow signals in thoracic lesions. The values of resistive index (RI) and pulsatility index (PI) of color Doppler US pulsatile flow signals in lung cancers and benign lesions were measured, analyzed, and compared. In the enrolled 153 patients with thoracic lesions, 61 lung cancers and 34 benign lesions had detectable color Doppler US pulsatile flow signals, and lung cancers had lower RI and PI values than benign lesions (RI: 0.70+/-0.03 vs. 0.79+/-0.04, p < 0.05; PI: 1.61+/-0.15 vs. 2.44+/-0.25, p < 0.005). However, overlapping RI and PI values in lung cancers and benign lesions somewhat limited color Doppler US pulsatile flow signals to differentiate lung cancers from benign lesions. Further analysis of RI and PI values in subgroups of lung cancers [squamous cell carcinoma (SCC, n = 34), adenocarcinoma (AC, n = 18), and small-cell lung cancer (SCLC, n = 6)] and benign lesions [cavitary benign lesions (CBL, n = 8), and noncavitary benign lesions (NCBL, n = 26)] revealed that all different cell types of lung cancers (SCC, AC, and SCLC), indeed, had lower RI and PI values than NCBL (for RI, all p < 0.01; for PI, all p< or =0.001). Moreover, the mean RI and PI values showed a significant incremental decrease from NCBL (mean RI, PI = 0.88, 2.94) toward SCC and AC (for SCC, mean RI, PI = 0.71, 1.68; for AC, mean RI, PI = 0.68, 1.67) and, finally, to SCLC (mean RI, PI = 0.62, 1.05). In contrast, CBL had relatively lower RI and PI values than AC and SCLC (for CBL, mean RI, PI = 0.53, 0.80; both p > 0.05 for RI and PI), and even a significant difference from SCC (p < 0.05 for RI and PI). We conclude that color Doppler US pulsatile flow signal is somewhat limited to differentiate lung cancers from benign lesions, but provides a noninvasive in vivo model to assess the neovascularity intensity of lung cancers.

Adenocarcinoma↗