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Biomedical subjects

S C Yu

Publications and source records attributed to S C Yu.

98 records · Page 6Linked to original sources
PubMed1972

Thyrotropin increases prostaglandin levels in isolated thyroid cells.

We have shown that two unrelated prostaglandin antagonists block both thyrotropin (TSH) and prostaglandins E (PGE(1), PGE(2)) stimulation of thyroidal adenyl cyclase activation and cyclic 3',5'-adenosine monophosphate (cAMP) formation, suggesting that prostaglandins play an important role in regulating thyroid function. To further explore this postulate, we measured prostaglandin content by radioimmunoassay in homogeneous bovine thyroid cell preparations in the presence and absence of TSH. Antibodies to albumin-conjugated PGE(1) and PGF(2alpha) showed specificity for prostaglandins E and F, respectively, but reacted, albeit far less effectively, with heterologous prostaglandins. A double antibody system was used to separate free from antibody-bound PGE(1)-(3)H and PGF(2alpha)-(3)H. Thyroid cells were extracted with ethanol/ethyl acetate and the various prostaglandins separated on silicic acid columns. Recoveries of added PGE(1)-(3)H and PGF(2alpha)-(3)H through the extraction and separation procedures ranged from 50-80%. The sensitivity of the method was 10-50 pg. Basal thyroid cell content of PGE(1) and PGF(2alpha) "equivalents" varied between cell preparations (range = 2-6 ng/0.2 ml cell suspension) but, in each instance, remained constant during 5-30-min incubations at 37 degrees C. TSH, 10-100 mU/ml, increased the levels of cell PGE(1) and PGF(2alpha) "equivalents" 30-80% above basal during 5-15-min incubations. The stimulatory effect was specific for TSH, no increase in PGE(1) or PGF(2alpha) "equivalent" levels being seen with luteinizing hormone (LH), human growth hormone (HGH), adrenocorticotropic hormone (ACTH), or glucagon. These data support the thesis that prostaglandins may mediate TSH effects on thyroid.

Adenylyl Cyclases↗
PubMedDate not supplied

A numerical investigation on the steady and pulsatile flow characteristics in axi-symmetric abdominal aortic aneurysm models with some experimental evaluation.

Steady and pulsatile flow characteristics in rigid abdominal aortic aneurysm (AAA) models were investigated computationally (using Fluent v. 4.3) over a range of Reynolds number (from 200 to 1600) and Womersley number (from 17 to 22). Some comparisons with measurements obtained by particle image velocimetry under the pulsatile flow conditions are also included. A sinusoidal inlet flow waveform 1 + sin omega t with thin inlet boundary layers was used to produce the required pulsatile flow conditions. The bulk features of the mean flow as well as some detailed features, such as wall shear stress distributions, are the foci of the present investigation. Recirculating vortices appeared at different phases of a flow cycle causing significant spatial and temporal variations in wall shear stresses and static pressure distributions. A high level of shear stresses usually appeared at the upstream and downstream ends of the bulge. Effects of pressure rise caused by the increase in cross-sectional area were transmitted into the downstream tube. Further simulation studies were conducted using simulated physiological waveforms under resting and exercise conditions so as to determine the possible implication of vortex dynamics inside the AAA model.

Aortic Aneurysm, Abdominal↗
PubMedDate not supplied

Solid-phase extraction in amphetamine and methamphetamine analysis of urine.

A systematic evaluation that compares the recoveries of methamphetamine and amphetamine from spiked urine using C8, C18, strong cation exchanger (SCX), and C8-SCX mixed procedures (solid-phase extraction) is reported. Optimized experimental conditions including pH of the sample, solvent composition, and urine concentration for different solid-phase extraction sorbents were studied. The largest recoveries--greater than 86% for methamphetamine and greater than 88% for amphetamine--were achieved with a mixed adsorbent (C8-SCX) and mixed elution solvent CH2Cl2-i-propanol-NH4OH (78:20:2) at pH 6. The concentration of the urine matrix did not affect the extraction efficiency. The detection limits of methamphetamine and amphetamine in urine were obtained at 0.03 and 0.07 micrograms/mL, respectively, using gas chromatographic-mass spectrometric analysis operated in the electron impact mode.

Adsorption↗
PubMedDate not supplied

Serum hepatocyte growth factor before and after resection for hepatocellular carcinoma.

BACKGROUND/AIMS: Hepatocyte growth factor (HGF) is the most potent hepatocyte proliferation stimulator. Serum HGF levels are high in various liver disease states such as cirrhosis, hepatocellular carcinoma (HCC) and hepatitis. But the role HGF plays in HCC is not clear at present. The purposes of this study are: 1) to reveal the HGF profile pre- and post-HCC resection, which has not been well-described before; and, 2) to analyze the relationships between the pre- and post-operative HGF levels and various clinical parameters. METHODOLOGY: We performed a retrospective cohort study to check the HGF profiles before and after curative resections for HCC and to analyze the relationships between them by using clinical parameters from 35 consecutive patients at the Department of Surgery, National Taiwan University Hospital. Blood samples collected from another 23 healthy individuals admitted for health check-ups were used as normal controls. Serum HGF was determined with an ELISA kit. RESULTS: The baseline HGF concentration in HCC patients was significantly higher than that in normal controls (1743+/-73 vs. 948+/-54 pg/ml, p<0.0001). The HGF concentrations on post-operative days (POD) 1, 3, 5, 7, and 14 were all significantly higher than those seen in normal controls (all p less than 0.0001). The first and third POD HGF values were significantly higher than the pre-operative level (p=0.00135 and 0.00187 respectively). The HGF concentrations would return to the pre-operative level on the fifth POD, but they never returned to normal level at the end of the two-week study. The pre-operative HGF level was affected by patient age (p=0.0236), and the post-operative peak HGF level was positively correlated with the pre-operative indocyanin green retention rate (ICGR15) and GOT level (p=0.0320 and 0.0234 respectively). CONCLUSIONS: In this study, we proved, indirectly, that HGF was not secreted by the HCC tumor cells per se. The peak post-operative HGF level reflected the relative stress of the operation on the diseased liver, but did not reflect the absolute physical extent of liver resection. The relationships between HGF and the prognosis of the patients after HCC resection demands further investigation.

Adult↗
PubMedDate not supplied

Laparoscopic wedge resection of benign gastric tumor.

BACKGROUND/AIMS: In the past 2 years, 9 patients diagnosed as benign gastric tumor pre-operatively underwent laparoscopic wedge resection of stomach at National Taiwan University Hospital. Among them, 6 were females and 3 were males. METHODOLOGY: Histopathologically, 7 of 9 cases were of gastrointestinal stromal tumor (GIST). The clinical characteristics of this group were retrospectively reviewed and compared with another 12 cases of benign gastric tumor receiving open wedge resection in the same period. RESULTS: There were no differences in sex, age, and pre-operative diagnosis in these two groups. It took a significantly longer operation time in the laparoscopic group than it did in the open group (205.71 vs. 97.5 min, p<0.05). However, the patients of the laparoscopic group started post-operative oral intake earlier (4.0 vs. 5.58 days, p<0.05), had shorter hospital stays (6.67 vs. 10.77 days, p<0.05), and lower analgesic usage rate (55% vs. 100%). There were no differences in operative complication rates. CONCLUSIONS: Laparoscopic resection of benign-gastric tumor is recommended as a minimally invasive procedure.

Adult↗
PubMedDate not supplied

[Insulinoma in childhood--report of a case].

A 14-year-old boy was having recurrent hypoglycemia over the past 6 months, so he was brought to our hospital for further evaluation. During the episodes of hypoglycemia, his serum insulin level was inappropriately high and the symptoms of hypoglycemia were dramatically ameliorated by intravenously administering glucose bolus. Computed tomography of the abdomen revealed a 1 x 1 cm mass located at the tail of the pancreas. Under the impression of an insulinoma, enucleation of the tumor was performed smoothly, and the pathological finding confirmed the diagnosis. The postoperative course was smooth and no episodes of hypoglycemia were noted after treatment. In children with hypoglycemic attacks, adequate blood sampling before correction to determine plasma insulin levels is essential.

Adolescent↗
PubMedDate not supplied

Experiences in surgical management of cavernous hemangioma of the liver.

BACKGROUND/AIMS: Observation is usually recommended for managing patients with cavernous hemangioma of the liver. To assess the indications for surgical management, we make a retrospective analysis. PATIENTS AND METHODS: There were 14 patients with cavernous hemangioma of the liver who were surgically treated in National Taiwan University Hospital from 1984 to 1993. RESULTS: The surgical indications included uncertain diagnosis in 10 patients, progressive tumor enlargement in two, symptomatic tumor in one and subcapsular bleeding in one. The tumors were 2-15 cm in diameter and the median was 6 cm. The operation procedures included atypical hepatectomy in 6 patients, lateral segmentectomy in 4, right lobectomy in one, extended right lobectomy in one and open biopsy in two. There was no mortality. Wound infection occurred in one patient. The average blood transfusion was 0.79 unit (range: 0-3 units)(1 unit=500 ml). The postoperative hospital stay was 13.2 days (range: 10-18 days). CONCLUSION: Surgical management of cavernous hemangioma of the liver is safe.

Female↗