Biomedical subjects

C L Chen

Publications and source records attributed to C L Chen.

At least 19 recordsLinked to original sources

PubMed1992

High-performance liquid chromatographic determination of BRB-I-28, a novel antiarrhythmic agent, in dog plasma and urine.

A sensitive reversed-phase high-performance liquid chromatographic (HPLC) technique with ultraviolet detection has been developed to determine the concentration of BRB-I-28 (I), a novel antiarrhythmic agent, in dog plasma and urine. The mobile phase was acetonitrile-methanol-37.5 mM phosphate buffer, pH 6.8-triethylamine (50:50:75:0.1, v/v). The compound was extracted from dog plasma and urine with chloroform after alkalinization with sodium hydroxide. The extraction recovery was 83% from plasma and 84% from urine. Good linearity (r > 0.996) was observed throughout the ranges 0.1-12.0 micrograms/ml (plasma) and 0.1-8.0 micrograms/ml (urine). Intra- and inter-assay variabilities were less than 4%. The lower limit of quantitation was 0.08 microgram/ml in either plasma or urine. HPLC analysis of plasma and urine samples from a dog treated with I has demonstrated that the method was accurate and reproducible.

Animals↗

PubMed1992

Liver transplantation in Taiwan: the Chang Gung experience.

Between March 1984 and February 1991, six orthotopic liver transplantations were performed at the Chang Gung Memorial Hospital in Taiwan. The indications for transplantation were Wilson's disease (5 patients) and biliary atresia (1 patient). Donors and recipients were matched only for size and ABO blood group compatibility, and the recipient operations were performed without the use of a venovenous bypass. Arterial reconstruction was carried out by end-to-end hepatic artery anastomosis (4), thoracic aortic conduit (1), or interposition of an iliac artery graft (1), whereas biliary reconstruction was accomplished by a choledochocholedochostomy using a T-tube stent (4) or a choledochocholedochostomy using an external cholecystostomy without stenting (2). Biliary complications occurred in three patients, and all required additional surgery. The average duration of donor-liver cold ischemia, operating time, and blood loss during surgery were 7 h and 50 min (range, 4.5-9 h), 13.5 h (range, 11.8-17 h), and 4,385 ml (range, 750-12,000 ml), respectively. The immunosuppressive regimens included a cyclosporin-steroid combination (n = 2) and a triple-drug combination (n = 4). All except one of the surviving patients experienced at least one rejection episode that was reversed by a methyl-prednisolone bolus and/or recycle. One patient developed a primary cytomegalovirus (CMV) infection that responded well to Ganciclovir treatment. Two of the patients died, one of injuries sustained in a traffic accident 3 years after transplantation, and the other of massive upper gastrointestinal bleeding. The overall survival value at 3 months was 83%, and the follow-up period ranged from 3 months to 7 years. All of the survivors have achieved complete rehabilitation and currently enjoy an excellent quality of life with normal liver function. Although the present study involved a small number of cases, our results indicate that liver transplantation can be successfully achieved in a high proportion of patients with acceptable morbidity, mortality, and cost in an Asian setting. The extreme shortage of donor organs is currently the most important obstacle limiting the application of liver transplantation in Taiwan.

Adolescent↗

PubMed1992

Stimulation of muscarinic cholinoceptive neurons in the hippocampus evokes a pressor response with bradycardia.

The injection of neostigmine into the hippocampus of anesthetized rats increased the mean arterial blood pressure (17% of baseline after 60 min injection) and decreased the heart rate (24% of baseline after 60 min injection). These changes were blocked by the co-administration of methylatropine into the hippocampus. Intrahippocampal injection of neostigmine stimulated the secretion of epinephrine and norepinephrine. Adrenodemedullation did not suppress the increase in blood pressure and the decrease in heart rate. It is concluded that the stimulation of muscarinic cholinoceptive neurons in the hippocampus evokes a hypertensive response via an increase in sympathetic drive to the heart and peripheral vasculature, with bradycardia possibly mediated via the parasympathetic system.

Animals↗

PubMed1992

Characterization of a major member of the rat pregnancy-specific glycoprotein family.

The gene encoding the human pregnancy-specific glycoprotein (PSG) belongs to a gene subfamily, comprised of the carcinoembryonic antigen (CEA) and PSG subgroups, within the immunoglobulin superfamily. To study the functional roles of PSG during development in an animal model, we isolated and characterized a near full-length cDNA (rnCGM6) encoding a PSG-related protein from a rat placental cDNA library. rnCGM6 is 2,068 bp in length and contains an open reading frame that encodes a 475-amino-acid polypeptide with a predicted molecular mass of 53 kD. The 5' noncoding sequence is 173 nucleotides, and primer-extension experiments demonstrate that the transcriptional initiation site is located 22-24 nucleotides further upstream. The 3' noncoding sequence contains 470 nucleotides which is followed by a poly(A) tail. In contrast to human PSGs, which contain one immunoglobulin variable-like and two to three immunoglobulin constant-like protein domains, rnCGM6 contains three immunoglobulin variable-like domains and one immunoglobulin constant-like domain. rnCGM6 contains six potential N-linked glycosylation sites and, in its carboxyl-terminal domain, a tyrosine protein kinase phosphorylation site. The tyrosine phosphorylation site is conserved among all rat and human PSG members. rnCGM6 hybridized with a major 2.5-kb and two minor 3.0- and 3.5-kb mRNAs, all primarily expressed in the rat placenta. Ribonuclease protection analysis, using probes specific to the 5', middle, and 3' regions of rnCGM6, and the 5' region of a previously identified cDNA, rnCGM1, mainly yielded fully-protected fragments indicating relatively low sequence similarity among rat PSG-related proteins. Northern hybridization and ribonuclease protection assays also suggest that rnCGM6 may be the major PSG member in rat.

Amino Acid Sequence↗

PubMed1992

Endometrial immunoreactive beta-endorphin increases during mid-estrous cycle and early pregnancy in gilts.

Immunoreactive (ir) beta-endorphin (BEND) was recently identified in porcine uterine fluids. In the study reported here, we examined the hypothesis that porcine endometrium serves as a source of uterine fluid ir-BEND during the estrous cycle and early pregnancy. Endometrial ir-BEND was chromatographically characterized, sites of ir-BEND synthesis were immunocytochemically localized, and concentrations of endometrial ir-BEND during the estrous cycle and early pregnancy were measured. Sephadex G-50 chromatographic profiles of endometrial extracts from Day 15 of the estrous cycle revealed three distinct peaks of ir-BEND, with the first peak occurring near void volume and the second and third peaks coinciding with standard porcine beta-lipotropin and standard porcine BEND, respectively. Reverse-phase HPLC C18 chromatographic profiles indicated that endometrial ir-BEND contained both standard BEND and alpha-N-acetylated BEND. Immunocytochemical studies demonstrated ir-BEND in the surface and glandular epithelial cells of the endometrium, with immunostaining most prominent in the apical portion of epithelial cells. Concentrations of ir-BEND in endometrial tissues were higher on Days 14-15 than on Days 8-12 during the estrous cycle and pregnancy (p less than 0.05); however, values were not different in pregnant and cyclic gilts. Biochemical and immunocytochemical evidence supports our hypothesis that ir-BEND present in uterine fluids is derived from the endometrium. The increase in endometrial ir-BEND concentration during Days 14-15 in cyclic and pregnant gilts indicates that ovarian steroids may influence the synthesis of endometrial ir-BEND.

Animals↗

PubMed1992

Effects of follicle-stimulating hormone on inhibin release by different testicular compartments in the adult ram.

The aim of this study was to determine the bidirectional release of immunoreactive inhibin-alpha (irINH-alpha) by different testicular compartments in the adult ram and to assess the effects of FSH on the distribution of inhibin in the testis. Immunoreactive INH-alpha was measured by RIA in fluid samples collected concurrently from the three testicular compartments--the seminiferous tubules, the interstitium, and the vascular system--through catheters inserted surgically into the rete testis, testicular lymphatic duct system, and spermatic veins, respectively. Overall, the concentration of irINH-alpha in rete testis fluid was 25 times the level in testicular lymph and over 500 times the concentration in peripheral blood. The pattern of irINH-alpha concentration in rete testis fluid was inversely related to that in testicular lymph, but i.v. administration of FSH had a decoupling effect on this relationship by depressing inhibin concentration in testicular lymph without affecting inhibin levels in rete testis fluid. Nevertheless, increased flow of testicular lymph more than compensated for the transient fall in irINH-alpha concentration so that, overall, the total output of inhibin via the testicular lymphatic duct system (and the vascular system) increased significantly. No persistent or significant changes were observed in the flow rate of rete testis fluid or concentration of irINH-alpha in the fluid after administration of FSH. The time frame for the response of the testis to FSH is indicative of the involvement of a mediator. Electrophoretic analysis of serially collected testicular lymph samples consistently revealed an FSH-induced release of a series of proteins in the M(r) range of 30,000-32,000.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Synovial and serum levels of triamcinolone following intra-articular administration of triamcinolone acetonide in the horse.

Seven mature thoroughbred horses, weighing between 400 and 541 kg, were each injected intra-articularly into three joints with 6 mg/joint of triamcinolone acetonide (Vetalog). The fourth joint, the control, was injected with saline. Synovial fluid was taken from all four legs of the horses on days 1, 2, 3, 4, 5, 6, 7, 8, 11, and 15 following the injections. Triamcinolone acetonide was assayed by a radioimmunoassay. Blood was collected at 1, 2, 4, 6, 12 h and on days 1, 2, 3, 4, 5, 6, 7, 8, 11, and 15 following injection of either triamcinolone or saline. Both cortisol and triamcinolone were assayed. The results show that the synovial fluid level of triamcinolone was 7.5 micrograms/ml 1 day following treatment and decreased to 10 ng/ml by the 4th day. These low levels were maintained for approximately 14 days. By the 15th day, the triamcinolone was below a detectable level. Serum levels of triamcinolone increased to 3 ng/ml within 1 h and further increased to a peak of 4.3 ng/ml at 4th h. The level then decreased to 2 ng/ml at 24 h and to nearly an undetectable level in 48 h. The mean level of serum cortisol, on the other hand, gradually decreased as the serum level of triamcinolone increased. As the serum level of triamcinolone reached an undetectable level on the 2nd day, the serum cortisol level gradually increased and returned to the pre-administration level by the 5th day. These results showed that the intra-articular administration of triamcinolone maintained triamcinolone in the synovial fluid for 4-14 days and that the triamcinolone reached the blood within 1 h. The serum level of triamcinolone was maintained for 2 days and resulted in the inhibition of adrenal function for 4 days.

Animals↗

PubMed1992

Cyclic adenosine 3',5'-monophosphate negatively regulates clusterin gene expression in Leydig tumor cell lines.

The clusterin protein and its messenger RNA were identified in many tissues including testis. In this report, we demonstrate the expression of clusterin gene in four Leydig tumor cell lines, including mouse MA-10 and I-10 and rat R2C and LC-540. When the cells were incubated with 0.1 mM 8-bromo-cAMP or (Bu)2cAMP for 17 h, an unexpected, profound suppression of clusterin mRNA accumulation was observed. A 60-70% decrease in clusterin mRNA was observed in MA-10 and R2C cells, 10% in I-10 cells, and no apparent change in LC-540 cells. The inhibitory effect of cAMP was specific to the clusterin gene, since in the same cells cholesterol side-chain cleavage enzyme mRNA was drastically elevated in MA-10 and I-10 cells while alpha-tubulin mRNA levels were not changed in all four cell lines. The reduction could be detected as early as 4 h, and was evident at 17 h after cAMP administration. Removal of cAMP from culture media at 17 h prevented the decline of clusterin mRNA. The suppression of clusterin gene expression can also be demonstrated by treatment with human CG or forskolin, which were known to elevate intracellular cAMP levels. Our observations suggest: 1) cAMP negatively regulates clusterin gene expression in two Leydig tumor cell lines, MA-10 and R2C; 2) The inhibitory effect of cAMP on clusterin gene expression is probably acting through the protein kinase A pathway; and 3) The four Leydig tumor cell lines respond differently to cAMP in the expression of clusterin and side-chain cleavage genes.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1992

Cardiac metastasis of hepatocellular carcinoma mimicking pericardial effusion on radionuclide angiocardiography.

A 51-year-old man presented with exertional dyspnea for two months. He had a history of hepatocellular carcinoma that was totally resected three years earlier. Radionuclide angiocardiography disclosed a large photopenic area separating the heart from the liver, and lung blood pools mimicking a large pericardial effusion. Echocardiography and magnetic resonance imaging of the heart, however, showed extensive tumor infiltration of the myocardium of both ventricles. Endomyocardial biopsy confirmed the diagnosis of metastatic hepatocellular carcinoma. There was no evidence of recurrent hepatoma in the liver.

Carcinoma, Hepatocellular↗

PubMed1992

Expression of the clusterin gene in the tissues of Booroola sheep which were homozygotes or non-carriers of the fecundity gene FecB.

Clusterin or sulphated glycoprotein-2 is a major component of the rete testis fluid, synthesized by the rete testis epithelial cells and Sertoli cells. Differences in the two-dimensional polyacrylamide gel electrophoresis pattern of clusterin-like proteins have been reported in rete testis fluid from Booroola rams carrying the fecundity gene FecB, when compared with that from non-carrier rams. In order to determine whether the FecB gene influences the expression of the clusterin gene, we used a rat clusterin cRNA probe to investigate mRNA species in the tissues of homozygous (BB) or non-carrier (++) Booroola sheep. Northern blots of polyadenylated RNA showed hybridization to the cRNA probe in the testis, ovarian follicles, corpora lutea and stroma, pituitary and liver. A major mRNA transcript was observed at 2.3 kb and a minor transcript in some tissues at 0.8 kb. Densitometry of the autoradiographs revealed no FecB-specific differences in the densities of the hybridization signals from ++ and BB testis or ovarian follicle, corpora lutea or stromal RNA. We conclude that the gene for ovine clusterin is expressed widely in the tissues of sheep and that its expression is not affected by the presence of the FecB gene.

Animals↗

PubMed1992

Clusterin production in the obstructed rabbit kidney: correlations with loss of renal function.

Clusterin, a protein associated with cell death, has been suggested as a marker of renal injury. Correlation of clusterin gene expression with changes in renal function and quantitative measurement of clusterin protein levels after ureteral obstruction have not been previously reported. With unilateral ureteral obstruction in rabbits as the experimental model, the time course of alterations in renal function, clusterin mRNA accumulation, and concentrations of clusterin protein in serum, urine, and renal tissue were investigated. RBF, GFR, and renal concentrating ability (percent sodium reabsorption and urine osmolarity) all decreased (P < 0.05) in the obstructed kidney from control values within 1 day of ureteral obstruction. Clusterin mRNA levels started to rise in the ipsilateral kidney within 12 h of ureteral obstruction and increased up to 10-fold above control levels after 3 days of obstruction. Hybridization histochemistry showed that clusterin mRNA was initially detectable in collecting ducts and distal tubules within 12 h of ureteral obstruction. After 7 days of obstruction, increased accumulation of clusterin mRNA was also detectable in proximal tubular epithelial cells. Clusterin gene expression remained elevated in collecting ducts after 60 days of obstruction. Clusterin expression in the contralateral kidney was increased twofold over control values after 12 h of obstruction. No increase in clusterin mRNA accumulation was detectable after 24 h in the contralateral kidney. Total clusterin protein in the obstructed kidney increased from 0.59 +/- 0.66 (mean +/- 1 SD) to 2.5 +/- 1.3 micrograms after 7 days of ureteral obstruction (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Measurement of urinary clusterin as an index of nephrotoxicity.

Measurements of tissue immunoassayable clusterin, a protein associated with programmed cell death and tissue reorganization, were performed in rats treated with nephrotoxic doses of gentamicin sulfate. Adult Lewis rats were treated with 100 mg/kg/day of gentamicin sulfate for 12 days. Urine, serum, and tissue levels of clusterin protein were measured, as were urinary N-acetyl beta-glucosaminidase (NAG) and serum creatinine levels. Induction of renal injury by gentamicin was detectable within 4 days by increased levels of urinary N-acetyl beta-glucosaminidase (from 280 +/- 66 (mean +/- SD) to 910 +/- 210 nmol/mg creatinine), and within 9 days of initiating gentamicin treatment by increased serum creatinine (from 0.5 +/- 0.1 to 1.2 +/- 0.4 mg/dl). Paralleling these changes, renal, urinary, and serum levels of clusterin increased 10-, 116-, and 3-fold (P less than 0.05). Treatment with gentamicin sulfate did not increase clusterin levels in the seminal vesicle, ventral prostate, testis, or epididymis. The measurement of urinary or serum clusterin may play a role in the early detection of renal injury.

Acetylglucosaminidase↗

PubMed1992

Congenital bronchoesophageal fistula in the adult: a case report.

The case of a 50-year-old woman with congenital bronchoesophageal fistula is presented. The patient had symptoms of hemoptysis provoked by ingestion of liquids for 2 years. A barium swallow examination showed a bronchoesophageal fistula communicating between the middle third of the esophagus and right intermediate bronchus. An orifice of the fistula at the esophagus was revealed by esophagoscopy. The clinical and operative features and diagnosis of congenital origin are discussed.

Bronchial Fistula↗

PubMed1992

Electrophysiological basis for the bradycardic effects of 1-(1-pyrrolidinylmethyl)-2-naphthol in rodents.

In anesthetized rats, intravenous injection of 1-(1-pyrrolidinylmethyl)-2-naphthol (TPY-beta, 0.1-1 mg/kg) induced a transient (less than 1 min) decrease in arterial blood pressure and heart rate (acute responses) followed by a delayed and sustained (greater than 10 min) bradycardic response. The electrophysiological mechanisms responsible for the bradycardic effect of TPY-beta were studied in sinoatrial tissues isolated from guinea-pig hearts. Transmembrane action potential (AP) and twitch force of atrial tissues were recorded with the conventional microelectrode techniques. In sinoatrial pacemakers active spontaneously in 4 mM [K]o Tyrode solution, TPY-beta (3-100 microM) depressed the diastolic slope and the rate of spontaneous discharges. When the non-automatic atrial tissues were driven at a fixed rate, TPY-beta (10-100 microM) inhibited the upstroke velocity of phase-0 depolarization and prolonged AP duration. In atrial fibers depolarized in high [K]o (24 mM), TPY-beta depressed the phase-0 upstroke of slow response AP and the twitch force in a concentration-dependent manner. The present results indicate that TPY-beta induced direct negative chronotropic and inotropic effects on guinea-pig atrial pacemakers and myocardial fibers. The underlying mechanisms involve a general inhibition of transmembrane of Ca, K and Na ion fluxes.

Action Potentials↗

PubMed1992

Effects of BRB-I-28, a novel antiarrhythmic agent, and its derivatives on cardiac Na+,K(+)-ATPase, Mg(2+)-ATPase activities and contractile force.

The effects of BRB-I-28, SAZ-VII-22 and SAZ-VII-23, a novel class of antiarrhythmic agents and other 3,7-diheterobicyclo[3.3.1]nonane (DHBCN) derivatives on guinea pig myocardial Na+,K(+)-ATPase and Mg(2+)-activated ATPase activities were investigated in comparison with those of tedisamil, lidocaine and ouabain. BRB-I-28, SAZ-VII-22, SAZ-VII-23, tedisamil and their derivatives produced concentration-dependent inhibition on both Na+,K(+)-ATPase and Mg(2+)-activated ATPase. Ouabain had no effect on the Mg(2+)-activated ATPase activity and GLG-IV-44 had no significant inhibition on Na+,K(+)-ATPase. Molar refractivity, retention time in reverse-phase HPLC, and partition coefficients were determined and the influence of these three parameters on the inhibitory effects of DHBCN on ATPase was examined. It seems that inhibitory effects of DHBCN derivatives on Na+,K(+)-ATPase and Mg(2+)-activated ATPase increase with an increase in lipophilicity, while hydrophilic groups of the drugs may not be important for interaction between drugs and ATPases. The effects of BRB-I-28 on contractile force development in rabbit atrial and papillary muscles were studied. At paced rates of 0.5 and 1.0 Hz in atrial muscle, BRB-I-28 produced an apparent positive inotropic effect in isolated rabbit atrial muscle, which is consistent with its inhibitory effects on Na+,K(+)-ATPase and Mg(2+)-ATPase activities. Inhibitory effects on myocardial Na+,K(+)-ATPase and Mg(2+)-activated ATPase activities may be the basis of some electrophysiological effects of antiarrhythmic properties of BRB-I-28, SAZ-VII-22, SAZ-VII-23, and tedisamil.

Animals↗

PubMed1992

Surgical treatment of metastatic lung tumor.

Since the first pulmonary resection for metastatic cancer of the lung in 1939, the following procedure can now be offered to any patient who meets these criteria: 1. a controlled primary tumor, 2. resectable lung lesion, 3. unavailability of a better treatment and 4. a good surgical candidate. From 1982 to 1992, there were 42 patients who underwent an operation for pulmonary metastasis at the Taichung Veterans General Hospital. Their cumulative 3-year and 5-year survival rates were 35% and 25% respectively. The overall estimated median survival time was 23.1 months. The overall operative mortality was 2.4% (1/42). We analyzed the effect of different types of primary tumors, the disease-free interval, and the number of lesions on patient survival. In our series, we concluded that none of the above had an effect on the therapeutic results.

Adolescent↗

PubMed1992

[Multiple primary malignant neoplasms: a case report].

One individual with two or three malignant neoplasms is not uncommon. However, a patient with more than 5 primary malignancies is unusual. We present a 51-year-old female who developed 6 metachronous primary malignant neoplasms in a period of 10 years. The anatomic sites of neoplasms in this patient included the cervix, larynx, skin, left breast, bladder and right lung (middle lobe). All of the tumors were proven by pathologic examination, and each of these tumors was recognized as a distinct primary tumor. Aggressive surgical resection, post-operative irradiation and chemotherapy showed good response in this patient. This patient had no familial or hereditary tendencies but, definite impairment of the cellular immunity had been identified.

Breast Neoplasms↗

PubMed1992

[The efficacy of intravenous fentanyl patient-controlled analgesia for postoperative pain relief].

The safety and efficacy of patient-controlled analgesia used for postoperative pain relief were evaluated. Cumulative 24-hour requirements were analyzed for possible correlation with patient characteristics. All patients who used a patient-controlled analgesia device for postoperative pain relief were reviewed from June to October 1991. The device Baxter's basal/bolus infusor with patient control module, was used to deliver fentanyl in 379 patients. The fentanyl requirement, verbal analog pain score, first passage of flatus, side effects, sedative score, and degree of satisfaction were examined. The fentanyl requirement during the first 24 hours after operation was analyzed with regard to age, body weight, and sex. The daily fentanyl consumption in the first three postoperative days was 928 +/- 352 micrograms (n = 338), 553 +/- 259 micrograms (n = 220), and 490 +/- 222 micrograms (n = 71), respectively. The requirement for fentanyl during the first 24 hours after surgery was significantly higher than for the next two days (p-value < 0.001). Fentanyl consumption correlated well with body weight, and inversely with age. No difference was found between fentanyl consumption and sex (p-value = 0.4687). The mean time to the first passage of flatus in patients with abdominal surgery was 54.6 +/- 26.4 hours. The incidence of nausea, vomiting, and dizziness was similar, about 20% of patients. Itching was noted in 7% of patients. Oversedation (class 4) was found in three patients during the first operative day, the sedative score for other patients were around class 1-3. No patient exhibited signs of respiratory depression or withdrawal syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗