Search PubMed⌕ Search

Biomedical subjects

C C Chen

Publications and source records attributed to C C Chen.

At least 433 records · Page 24Linked to original sources
PubMed1994

The electrophysiological effects of dicentrine on the conduction system of rabbit heart.

1. The electrophysiological effects of dicentrine, an aporphine alkaloid isolated from the root of Lindera megaphylla, were examined in the Langendorff perfused rabbit heart and rabbit isolated cardiac cells. 2. Standard electrophysiological characters were measured in the Langendorff perfused rabbit heart (control study) and after 5 min exposure to 1, 3 and 9 microM of dicentrine and during the subsequent recovery phase sequentially (n = 7). The same study protocols were performed in 0.5 to 4.5 microM quinidine (n = 7), 18 to 162 microM procainamide and N-acetylprocainamide (n = 7) for comparison. 3. The results showed that the spontaneously beating heart rate and the sinoatrial (SA) and atrioventricular nodal (AH) conduction time were not significantly affected by dicentrine but were significantly suppressed by the higher doses of quinidine (4.5 microM) and procainamide (162 microM). 4. The His-Purkinje conduction time was significantly increased by the higher dose of dicentrine, quinidine and procainamide. 5. The ventricular repolarization time and its effective refractory period were significantly increased by the higher dose of dicentrine and the other agents. 6. The effective refractory period of the atrium, AV node and His-Purkinje system were also significantly increased by dicentrine and the other agents. 7. A voltage clamp study revealed that the prolongation of atrial action potential duration by dicentrine (9 microM) was associated with a significant inhibition of the transient potassium outward current. As well as inhibition of the transient outward current, a significant inhibition of the sodium inward current by dicentrine was found. 8.We conclude that (1) dicentrine is potentially a useful antiarrhythmic agent with type Ia and type III antiarrhythmic action; (2) the relative potency of dicentrine on the electrophysiological function of cardiac tissue is 10-20 times more than that of procainamide.

Action Potentials↗
PubMed1994

Inhibition by gomisin C (a lignan from Schizandra chinensis) of the respiratory burst of rat neutrophils.

1. The possible mechanisms of action of the inhibitory effect of gomisin C on the respiratory burst of rat neutrophils in vitro was investigated. 2. The peptide formyl-Met-Leu-Phe (FMLP) induced superoxide anion (O2-) formation and O2 consumption, which was inhibited by gomisin C in a concentration-dependent manner (IC50 21.5 +/- 4.2 micrograms ml-1 for O2- formation). Gomisin C also suppressed O2- formation and consumption at low concentrations of phorbol myristate acetate (PMA) with an IC50 value of 26.9 +/- 2.1 micrograms ml-1 for O2- formation. However, gomisin C did not affect the responses induced by a high concentration of PMA. 3. Gomisin C had no effect on O2- generation and uric acid formation in the xanthine-xanthine oxidase system, and failed to alter O2- generation during dihydroxyfumaric acid (DHF) autoxidation, indicating that it does not scavenge superoxide. 4. Like trifluoperazine (TFP), gomisin C attenuated the activity of PMA-activated neutrophil particulate NADPH oxidase in a concentration-dependent manner. 5. Gomisin C reduced the elevations of cytosolic free Ca2+ in neutrophils stimulated by FMLP in the presence or absence of EDTA. Cyclopiazonic acid (CPA) induced the release of Ca2+ from intracellular stores and this was also reduced by gomisin C. However, the Ca2+ influx pathway activated by CPA was not affected by gomisin C. 6. The cellular cyclic AMP level was markedly increased by forskolin, but not by gomisin C. Moreover, the inositol phosphate levels in FMLP-activated neutrophils were not affected by gomisin C. 7. These results show that the inhibitory action of gomisin C on the respiratory burst is not mediated by changes in cellular cyclic AMP or in inositol phosphates, or by scavenging O2- released from neutrophils, but may be mediated partly by the suppression of NADPH oxidase and partly by the decrease of cytosolic Ca2+ released from an agonist-sensitive intracellular store.

Animals↗
PubMed1994

Low frequency of the ADH2*2 allele among Atayal natives of Taiwan with alcohol use disorders.

Genetic variation at two polymorphic alcohol dehydrogenase loci, ADH2 and ADH3, and at the polymorphic mitochondrial aldehyde dehydrogenase locus, ALDH2, may influence the risk of developing alcoholism by modulating the rate of elimination of ethanol and the rate of formation and elimination of acetaldehyde. Populations differ in allele frequencies at these loci. We determined the genotypes at all three of these loci in Atayal natives of Taiwan. The frequencies of ADH2*2, ADH3*1, and ALDH2*1 alleles (0.91, 0.99, and 0.95, respectively) were significantly higher among the Atayal than among a predominantly Han Chinese population from Taiwan. Among the Atayal, the group with alcohol use disorders (alcohol dependence and alcohol abuse) had a significantly lower frequency of the ADH2*2 allele (0.82) than those without alcohol use disorders (0.91). The ADH2*2 allele encodes the beta 2 subunit; isozymes containing beta 2 subunits oxidize alcohol faster in vitro than the beta 1 beta 1 isozyme encoded by ADH2*1. Thus, the simplest explanation for these data is that individuals with a beta 2 isozymes have a higher rate of ethanol oxidation, which is a deterrent to alcohol abuse and dependence in some individuals. The Atayal with alcohol use disorders also had a lower frequency of ALDH2*2 than the controls; this allele is known to be responsible for the alcohol-flush reaction among Asians, and thereby deters drinking.

Adult↗
PubMed1994

Stroke associated with methamphetamine inhalation.

Seven patients (all men, mean age 32 years, range 17-47) with stroke following methamphetamine inhalation were collected during the last 2 years. Like oral or intravenous abusers, our patients had more hemorrhagic (n = 5) than ischemic strokes (n = 2). Cases of intracerebral hemorrhage (ICH) were lobar (n = 3), caudate (n = 1) or putaminal (n = 1), whereas the infarctions were both in the middle cerebral artery region. Each stroke event occurred within 3 days after drug use. Three patients had hypertension on admission. Though young in age, most patients had multiple stroke risk factors. In 3 patients with ICH, we also found small, low attenuated lesions on the brain computed tomography, however, without clinical correlations. Except for arteriovenous malformation in 1 patient, all angiograms failed to show vasculopathy or vasospasm. Contrary to what one might surmise from previously published reports, methamphetamine inhalation is at least as likely to produce ICH as it is to produce brain infarction.

Administration, Inhalation↗
PubMed1994

Physical conditioning decreases norepinephrine-induced vasoconstriction in rabbits. Possible roles of norepinephrine-evoked endothelium-derived relaxing factor.

BACKGROUND: Physical activity can reduce sympathetic tone and may be beneficial to human health. Whether the vascular responses to norepinephrine (NE), an adrenergic vasoconstrictor, could be altered by chronic exercise was unclear. We therefore conducted this study to investigate the effects of endurance exercise training on NE-induced vasoconstrictive response in healthy rabbits. Possible mechanisms were also studied. METHODS AND RESULTS: Twenty-four male New Zealand White rabbits were used for this study. They were divided into two groups: control and training. The training group was trained on a treadmill with running speed of 0.88 km/h at a 0 degree grade for 10 to 60 minutes per day, for 5 days a week for a total of 8 weeks. At the end of the experiments, thoracic aortae (3 mm long) were isolated. The vascular tension was measured with a force transducer. The dose-response relation of NE-induced vasoconstriction was determined and compared for control (n = 5) and trained (n = 6) groups. To verify the possible involvement of endothelium-derived relaxing factor (EDRF) in the alteration of NE-induced vasoconstriction after exercise training, we compared the vascular responses to NE in endothelium-intact, N omega-nitro-L-arginine (L-NNA, 10(-4) mol/L)-pretreated, or denuded vessel segments (n = 4 for each experiment of each group). EDRF release in the presence or absence of NE was also evaluated by the increased tension induced by hemoglobin (10(-5) mol/L), an EDRF scavenger (n = 6 for the control group and n = 8 for the trained group). In addition, vascular responses to some specific adrenergic agonists (ie, phenylephrine, an alpha 1-agonist, and clonidine, an alpha 2-agonist) were also studied to see if a specific adrenergic receptor was involved (n = 4 for each experiment of each group). Our results indicated that (1) [NE]ED50 of the thoracic aorta was elevated by exercise training; (2) in the presence of NE, EDRF release from the thoracic aorta, assessed by addition of hemoglobin or L-NNA, was higher in the trained group than in the control group; (3) both phenylephrine (10(-8) mol/L) and clonidine (10(-6) mol/L) could evoke vasorelaxation that would be inhibited by L-NNA; and (4) in addition to causing vasoconstriction, NE could stimulate EDRF release, possibly via alpha 1- and alpha 2-receptors of endothelial cells. CONCLUSIONS: Our data suggest that exercise training may decrease NE-induced vasoconstrictive response and may increase NE-stimulated EDRF release.

Animals↗
PubMed1994

Use of retinoic acids in the treatment of peripheral T-cell lymphoma: a pilot study.

PURPOSE: We have systemically analyzed, both in vitro and in vivo, the effect of 13-cis-retinoic acids (RA) on non-Hodgkin's lymphoma (NHL). METHODS: The in vitro growth-inhibitory effect of 13-cis-RA was examined in 11 (T cell, five; B cell, six) lymphoma cell lines by a tetrazolium colorimetric assay. A pilot clinical trial with oral 13-cis-RA 1 mg/kg/d was conducted in a selected group of 18 lymphoma patients, of whom 16 had failed to respond to at least one regimen of intensive chemotherapy. The in vitro and in vivo effects of 13-cis-RA were correlated with immunophenotypes, RA-induced changes of morphology, and patterns of DNA fragmentation of the lymphoma cells. RESULTS: Four of five T-lymphoma cell lines and none of six B-lymphoma cell lines were sensitive (concentration of 50% growth inhibition [IC50] < 1.5 microns) to 13-cis-RA (P = .015). In the clinical trial, five (two Ki-1, one angioinvasive type, one diffuse mixed cell, and one diffuse large cell) complete remissions and one (Ki1) partial remission were observed in 12 patients with peripheral T-cell lymphoma (PTCL), while none of six patients with B-cell lymphoma responded to 13-cis-RA. 13-cis-RA-induced cellular differentiation and apoptosis, as evidenced by the more mature morphology, characteristic nuclear condensation, and DNA ladder pattern signifying internucleosomal fragmentation, were demonstrated in the sensitive cell lines, as well as in the remitting lymphoma tissues. CONCLUSION: The 13-cis-RA appears to be active on lymphomas of T-lineage and their therapeutic indication may be extended to include some subtypes of PTCL. The mechanisms of action are related to differentiation and apoptosis of lymphoma cells. There appears to be no cross-resistance between 13-cis-RA and conventional chemotherapy.

Adult↗
PubMed1994

Serum pancreas-specific protein in acute pancreatitis. Its clinical utility in comparison with serum amylase.

To compare the clinical utility of serum pancreas-specific protein and serum amylase in the diagnosis of acute pancreatitis, the study was conducted in 134 normal subjects and 70 patients (36 with acute pancreatitis and 34 with other acute abdominal diseases as control group). The serum level of pancreas-specific protein in 134 healthy adults was 29.6 +/- 1.6 micrograms/l, with 95% within 7.3-67.2 micrograms/l. The upper reference limit was set at 70 micrograms/l. Serum levels of pancreas-specific protein and amylase within 12 h of arrival were significantly higher in patients with acute pancreatitis than in the control group (647.3 +/- 79.3 versus 33.8 +/- 4.8 micrograms/l (p < 0.0001) and 2536 +/- 344 versus 175 +/- 35 IU/l (p < 0.0001)). No significant difference in the levels of pancreas-specific protein was noted between biliary and alcoholic pancreatitis or between severe and mild attacks. The sensitivity, specificity, and accuracy of diagnosing acute pancreatitis were 100%, 94.1%, and 97.1% with serum pancreas-specific protein > 70 micrograms/l and 97.2%, 91.2%, and 94.3% with serum amylase > 360 IU/l. The result demonstrated that pancreas-specific protein may be a good serum marker in the diagnosis of acute pancreatitis.

Acute Disease↗
PubMed1994

Infantile endodermal sinus tumor presenting with vaginal bleeding: report of a case.

Endodermal sinus tumor (EST) of the vagina is extremely rare and primarily affects infants. We report on a six-month-old female infant with EST of the vagina who presented with vaginal spotting of one month's duration. Pelvic ultrasound and computerized tomography showed a 3.8 x 3.5 cm heterogeneous mass between the bladder and the rectum. The serum alpha-fetoprotein (AFP) level was high (1270 ng/mL) and the beta-human chorionic gonadotropin was undetectable. She received surgical intervention followed by chemotherapy. The patient was disease-free and serum AFP remained undetectable during the eight-month follow-up period.

Endodermal Sinus Tumor↗
PubMed1994

Acute intermittent porphyria: clinical analysis of nine cases.

BACKGROUND: Acute intermittent porphyria (AIP) is an uncommon disorder, characterized by a variety of nonspecific symptoms and signs. Many patients have undergone prolonged medical care for the condition without accurate diagnosis; some have even received unnecessary operation. Here the clinical features of nine cases are presented. METHODS: Nine patients with AIP were diagnosed and treated at this hospital during the period for 1986 to 1993. The medical records of these patients were reviewed, and diagnosis of AIP in all cases was confirmed by positive Watson-Schwartz test. In three cases, further confirmation was done with erythrocyte porphobilinogen (PBG) deaminase activity measurement. Patients with photosensitivity were excluded. RESULTS: All patients presented initially with abdominal pain; two had been operated upon for acute abdomen. Neurological presentations at diagnosis were motor and/or sensory polyneuropathy (6/9), autonomic dysfunction (6/9), mental change (5/9) and seizure (4/9). Two cases had hyponatremia. One patient died of intractable seizures. CONCLUSIONS: AIP is a frequently forgotten old disease; if not correctly recognized, repeated and unnecessary surgery may occur. However, the diagnosis is easy when the possibility of this disorder is kept in mind.

Acute Disease↗
PubMed1994

Persistent hyperinsulinemic hypoglycemia due to nesidiodysplasia in a neonate.

A large, one-hour-old female baby was noted to have hypoglycemia immediately after birth. Although early feeding and then intravenous glucose infusion with a dose gradually increased to 30 mg/kg/min were given, the baby still had recurrent hypoglycemia 14 days after birth. High serum insulin/glucose ratios (> 2.5) were noted twice during hypoglycemic episodes. At the same time, the baby's serum growth hormone, thyroid hormone and cortisol levels were within normal ranges. Hyperinsulinism due to nesidiodysplasia was diagnosed and a near-total pancreatectomy was performed at the age of 14 days. After the operation, euglycemia was achieved and there was no episode of hypoglycemia even after fasting for eight hours. Our experience confirms that surgery is the treatment of choice for patients, including neonates, with hyperinsulinemic hypoglycemia.

Female↗
PubMed1994

Temporal lobectomy in adults with intractable epilepsy.

We report on 30 adult patients with intractable complex partial seizure (CPS) of the temporal lobe origin who received anterior temporal lobectomy. The average follow-up period was 41 months. The age of onset was younger and the duration of epilepsy was longer in the non-mass lesion group than in the mass lesion group. Postoperatively, 21 patients (70%) were seizure-free, four patients (13%) had only rare seizures (less than three attacks per year), three patients (10%) achieved a remarkable reduction (more than 50%) of seizure frequency, and two patients (7%) showed no worthwhile improvement. Based on our experience, anterior temporal lobectomy is an effective and safe procedure for adult patients with intractable CPS. For diagnosis, magnetic resonance imaging (MRI) yielded a higher sensitivity rate than computed tomography (CT), especially in the group without mass lesions. Positron emission tomography using 18F-fluorodeoxyglucose (FDG-PET) was superior to single photon emission computed tomography (SPECT) which had a relatively high false localization rate. With high resolution MRI and FDG-PET, localization of the epileptogenic zone was more accurate. A preresection electrocorticogram (ECoG) was used to confirm the epileptogenic focus during the operation. The residual spikes on the postresection ECoG did not necessarily predict a poor seizure control outcome after anterior temporal lobectomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Exclusion therapy for terminal reservoir syndrome in children with repaired anorectal malformations.

Constipation, dyschezia and encopresis in association with fecal impaction in a hugely dilated ectatic terminal bowel were noted in 12 cases of imperforate anus after creation of an anorectal canal. The original anorectal malformations were of low anomalies in four cases, intermediate in one, and high in seven. Associated anomaly in the pelvis or sacrospinal area was present in four of the 12 cases, and dilated rectal pouch at birth was found in four of the eight patients examined. The symptom of constipation started invariably within a few months after anoplasty or closure of colostomy. Suction biopsy of the rectum excluded the possibility of aganglionosis. As elaborate conservative measures, including revision of the anteriorly displaced anus, failed to relieve the symptoms, exclusion of the ectatic terminal bowel by either excision or endorectal pull-through was carried out in nine of the 12 cases. The results were satisfactory: eight of the nine patients developed regular bowel movements and were totally continent within six months of surgery. It is suggested that the terminal reservoir is caused by primary rectal ectasia in the low anomalies and by primary or secondary ectasia, or a combination of both, in the high anomalies. Early exclusion of the ectatic terminal bowel is recommended for patients suffering from this syndrome after repair of anorectal malformations.

Anal Canal↗
PubMed1994

[Analysis of psychiatric inpatients in a general hospital].

A descriptive study on psychiatric inpatients of a general hospital was conducted. During a four-year- and -ten-month period, 1390 hospitalization admissions were analysed. Among them, 436 (31.4%) were diagnosed as mood disorder, 431 (31.0%) were schizophrenia, followed by other psychosis (231 admissions, 16.6%), organic mental disorder (164 admissions, 11.8%), neurosis (116 admissions, 8.3%) and other mental disorders (12 admissions, 0.9%). Male was predominant in organic mental disorders, while female was predominant in all the other diagnosis. The mean of hospitalization days was 34.7 +/- 27.4 days. Readmission was noted in 47.1% of total admissions, indicating that "revolving door syndrome" was also noted among mentally ill in our country. Schizophrenic patients had the longest hospitalizations and the highest readmission rate. Patients who were discharged against advise comprise 14.6% of all admissions. This frequency is within the estimate of 6.8% and 23.4% in other hospitals. Others characteristics of psychiatric inpatients in the general hospital were also discussed.

Adolescent↗
PubMed1994

Percutaneous transluminal angioplasty of neck vessels.

BACKGROUND: Although surgical endarterectomy or bypass is regarded as the treatment-of-choice for extracranial cerebral vascular stenosis, percutaneous transluminal angioplasty (PTA) has its role as an alternative procedure for symptomatic patients refractory to medical therapy and/or for whom surgical treatment is contraindicated. METHODS: Occlusive blood vessels were first identified by neurologic, ultrasonic and angiographic studies. Patients were premedicated with heparin and corticosteroid. From a transfemoral approach, double lumen balloon dilatation catheter was guided across the area of stenosis, and inflated two or three times to produce dilatation. Following PTA, patients received anticoagulants and corticosteroid for a period, and were followed by clinical examination, Doppler blood-flow and angiographic studies. RESULTS: Seventeen patients undergoing 26 procedures were included in this study. The lesions involved subclavian artery in nine cases, common carotid artery in seven, internal carotid artery in five and proximal vertebral artery in five. Digital subtraction angiography (DSA) was done immediately after PTA and showed improvement of stenotic segment (residual stenosis < 30%) in 22 vessels. Restenosis occurred in two cases of subclavian artery PTA six months later. There were three complications, including TIA in two cases and hematoma at the puncture site in one case. Clinically, symptomatic improvement was obtained in 13 cases. CONCLUSIONS: In patients with significant atherosclerotic stenosis of neck vessels, PTA is a beneficial procedure for improving blood flow to brain circulation and for alleviating symptoms.

Aged↗
PubMed1994

MR imaging evaluation of bone marrow signal change in post-irradiation patients with nasopharyngeal carcinoma.

BACKGROUND: The normal distribution of red and yellow marrow can be altered by therapeutic irradiation, which causes a well-documented sequence of bone marrow changes. This study measured the T1 signal intensity of the clivus and cervical vertebral bodies of NPC patients who had received a complete course of radiation therapy. METHODS: There were 3 categories of patients: Group I: NPC patients who had radiation myelitis; 14 persons which a total 20 times of MRI. Group II: NPC patients, without radiation myelitis; 6 patients, which a total 6 times of MRI. Group III (control group): patients who received MRI of the cervical spine because of cervical spondylosis or HIVD, were total of 45 patients. In the sagittal section of T1WI, the signal intensity of the bone marrow of clivus and C2 to T1 vertebral bodies was measured. RESULTS: 1). There were homogeneous increases of signal intensity of the bone marrow of clivus and C2 to T1 in Groups I and II. 2). There was no statistical difference between Groups I and II. 3). The increased signal intensity of bone marrow after radiation showed no difference in short and long duration between radiation therapy and MR examinations, indicating that bone marrow signal intensities were increased in NPC patients whether or not they had radiation myelitis. CONCLUSIONS: Signal change in bone marrow may have occurred soon after radiation therapy, and may have persisted for several years. The radiation myelitis always involved the low medulla oblongata to C5 level; however, the bone marrow signal change always extended downward to the T1 level, so bone marrow is more sensitive than the spinal cord and is prone to be affected by irradiation.

Adult↗
PubMed1994

A retrospective analysis of bone scan abnormalities in mastocytosis: correlation with disease category and prognosis.

UNLABELLED: To investigate the usefulness of bone scintigraphy in systemic mastocytosis (SM), the scans of 73 patients were retrospectively reviewed and correlated with disease category. METHODS: A modification of a previously described method for bone scan classification in this disease was used. In addition to the group as a whole, two subsets of patients with multiple bone scans were identified for closer analysis: those with (n = 13) and without (n = 12) scintigraphic evidence of progression of disease. RESULTS: Overall, patients with more aggressive SM tended to have increasingly abnormal initial bone scans (p2 = 0.0003), although there was a considerable degree of overlap. Of patients undergoing serial studies, those with scintigraphic progression also tended to have more aggressive disease (p2 = 0.006) and a poorer prognosis than those with stable bone scans. CONCLUSIONS: Both the degree of abnormality on initial bone scan and progression of scintigraphic abnormalities with serial scanning appear to correlate with the presence of more aggressive systemic mastocytosis. Based on the patterns seen, in many cases this may be a reflection of bone marrow expansion, which in turn probably reflects increased marrow disease.

Adolescent↗
PubMed1994

Thyrotoxicosis aggravated by iodinated contrast medium: a case report.

Thyrotoxicosis may be aggravated by the administration of either iodinated contrast medium or inorganic iodide. A case of subclinical hyperthyroidism aggravated by iodinated contrast medium is presented here. The patient had received right subtotal lobectomy of the thyroid gland for thyroid cyst in 1969. She had been well until February 1981, when she was found by 131I thyroid scan to have left nodular goiter. Thyroid function was in euthyroid state. Progressive enlargement of the left nodular goiter was noted in October 1987, with thyroid function still in the euthyroid state. Therefore, suppression therapy with L-thyroxine (Eltroxin 0.1 mg per day) was given for eight months until July 1988. The patient was lost to follow-up thereafter until she was admitted to the endocrine ward of the Veterans General Hospital-Taipei in August 1992 because of a progressively enlarged goiter associated with body weight loss. Serum T3 (127 ng/dl) and T4 (11.36 micrograms/dl) were within normal range, but TSH (0.06 microU/ml) was very low. The patient had exacerbated symptoms of hyperthyroidism and elevated serum T3 (216 ng/dl), T4 (18.19 micrograms/dl) levels one week after iodinated contrast medium injection, during a neck CT scan examination. The patient eventually received thyroid operation for her goiter and hyperthyroidism. Caution should be done in the administration of iodine-containing drugs, especially iodinated contrast medium in patients with pre-existing thyroid disease.

Contrast Media↗