Biomedical subjects

C C Chen

Publications and source records attributed to C C Chen.

At least 361 records · Page 20Linked to original sources

PubMed1996

A model of angiogenesis in the mouse cornea.

PURPOSE: The study of angiogenesis depends on reliable and reproducible models for the stimulation of a neovascular response. The purpose of this research was to develop such a model of angiogenesis in the mouse cornea. METHODS: Uniformly sized Hydron pellets containing either basic fibroblast growth factor (bFGF) or vascular endothelial growth factor (VEGF) and sucralfate were prepared and implanted into the stroma mouse cornea adjacent to the temporal limbus. RESULTS: Neovascularization of the corneal stroma began on day 3 and was sustained through day 8. The bFGF-induced neovascularization was consistent and dose dependent in C57B1/6, as well as in severe combined immune deficient, beige natural killer cell-deficient, and nude mouse strains. Biomicroscopic and histologic examination of bFGF- and VEGF-induced angiogenesis was notable for the absence of corneal edema or substantial inflammation. CONCLUSIONS: This noninflammatory model of corneal neovascularization is especially advantageous because it is reproducible, economical, and facilitates investigation of angiogenesis in various murine tumor models as well as in genetically defined murine strains.

Animals↗

PubMed1996

Alimentary tract duplications.

A total of 17 patients with alimentary tract duplications underwent surgery at National Taiwan University Hospital from 1978 to 1994. Fifteen patients (88%) had gastrointestinal duplication and two (12%) had esophageal duplication. Common presenting symptoms of gastrointestinal duplication were melena and abdominal pain. The ileum was the most common site of duplication. Multiple duplications were seen in three patients. All duplications were cystic, except for one single appendiceal duplication. Ectopic gastric mucosa was detected in nine of the 16 nongastric duplications. One patient with ileal duplication had ectopic pancreatic tissue. Twelve patients received resection of the duplication with a segment of bowel and primary anastomosis, three patients underwent simple excision and two patients had partial resection of the duplication and stripping of the residual mucosa. Two patients had other associated congenital anomalies: one had ventricular septal defect and the other, imperforate anus and malrotation of intestine. There was no operative mortality or morbidity in this series.

Abdominal Pain↗

PubMed1996

Characteristics of endoscopic retrograde cholangiopancreatogram in patients with primary biliary cirrhosis.

BACKGROUND: The findings of cholangiopancreatograms in patients with primary biliary cirrhosis vary markedly in literature. We tried to evaluate the changes of endoscopic retrograde cholangiopancreatograms in Chinese patients with primary biliary cirrhosis. METHODS: Twenty-nine patients with primary biliary cirrhosis underwent endoscopic retrograde cholangiopancreatography over the past 8 years. Three patients with a negative antimitochondrial antibody test were excluded. Well opacified cholangiograms and pancreatograms were obtained in 24 patients. Meanwhile, 16 subjects with normal cholangiopancreatogram served as controls. The characteristics and prevalence of abnormal cholangiopancreatograms in the patients and the correlation of radiography with clinical severity of the disease were evaluated. RESULTS: The maximum diameters of the common bile duct (9.7 +/- 4.0 vs. 7.6 +/- 0.9 mm, NS), right (5.0 +/- 1.6 vs. 4.4 +/- 1.2 mm, NS) and left (5.1 +/- 1.2 vs. 4.9 +/- 1.4 mm, NS) intrahepatic ducts did not show significant difference between the patients with primary biliary cirrhosis and the controls. Abnormal intrahepatic cholangiograms were obtained in 12 (50%) patients including eight with diminished arborization and focal stenosis, three with crowding and tortuous branches and one with focal stenosis alone. A hepatic hilum notch on the common hepatic duct was found in eight (33.3%) patients. The abnormalities of intrahepatic ducts did not correlate with age, sex, Pugh's scores, various liver function tests or histologically cirrhotic change. One (4.2%) patient had an abnormal pancreatogram. CONCLUSIONS: Abnormal intrahepatic cholangiograms are present in half of patients with primary biliary cirrhosis, but are not related to clinical severity.

Adult↗

PubMed1996

Decreased production of IFN gamma and increased production of IL-6 by cord blood mononuclear cells of newborns with a high risk of allergy.

BACKGROUND: The underlying mechanisms of elevated IgE level in atopic patients are still obscure, however, extensive efforts have been tried to identify an immunological parameter as a predictor of atopy. OBJECTIVE: This study compared the difference in cytokine production by cord blood mononuclear cells between new borns with high-risk of allergy (family allergy score, FAS > or = 3) and those with low-risk (FAS = 0). METHODS: Following stimulation with PHA (100 micrograms/mL) and PMA (1 ng/mL), the cytokines produced by cord blood CD4+ T cells in the presence of monocytes were measured by ELISA kits and the mRNA was detected by reverse transcription-polymerase chain reaction (RT-PCR) technique. RESULTS: Our results showed: CD4+ T cells in the presence of monocytes and isolated monocytes from the high-risk group produced a much greater amount of IL-6, either spontaneously or after stimulation, than did those of the low-risk group; CD4+ T cells of low-risk group produced a significantly greater amount of interferon gamma (IFN gamma) than did those from the high-risk group; IL-4 cannot be detected by ELISA kit, and only a trace amount of IL-4 mRNA was detected by RT-PCR technique; cord blood basophils stimulated with PHA and PMA could produce a significant amount of IL-4; there was an inverse correlation between the production of IFN gamma and cord blood IgE level (high-risk group, r = 0.647, n = 17) and the number of natural killer (NK) cells (CD3- CD16+ CD56+) was significantly lower in high-risk group than for low-risk group. CONCLUSION: Our data suggested increased production of IL-6 and decreased production of IFN gamma of cord blood mononuclear cells appear to be the hallmark of newborns from the high-risk population.

Basophils↗

PubMed1996

Optimal number of views in 360 degrees SPECT imaging.

UNLABELLED: This study examined SPECT-reconstructed image quality as a function of the number of views, and determined the minimum number of views necessary to remove aliasing artifacts in 360 degrees SPECT. METHODS: Computer simulation was performed using a two-dimensional Shepp-Logan head phantom and a high-resolution parallel-beam collimator with and without photon attenuation. RESULTS: In 360 degrees SPECT, aliasing artifacts were reduced by changing the number of views from an even number 16 to its neighboring odd numbers 15 or 17, from 32 to 31 or 33 and from 64 to 63 or 65. Image quality of 15 or 17 views, 31 or 33 views and 63 or 65 views was similar to that of 32, 64 and 128 views, respectively. CONCLUSION: Replacing an even number of views by its neighboring odd numbers in 360 degrees SPECT significantly decreased aliasing artifacts. Thirty-one or 33 views are sufficient to remove most of the aliasing artifacts in 360 degrees SPECT with a matrix of 64 x 64 pixels. This method can be applied to fast 360 degrees SPECT since fewer views are used.

Artifacts↗

PubMed1996

Clinical response of tuberculous pericarditis to medical treatment: a retrospective survey.

BACKGROUND: The prevalence of tuberculosis has declined with advanced antituberculous chemotherapy. However, the occurrence of subsequent constrictive pericarditis in tuberculosis has not reduced. Clinical progress of tuberculous pericarditis was investigated in patients receiving antituberculous chemotherapy. METHODS: Thirteen patients with tuberculous pericarditis (11 men and 2 women aged 14 to 86 years [mean 60.0 +/- 17.0]), treated initially with antituberculous medications were analyzed. All patients underwent pericardiocentesis on admission following echocardiography. RESULTS: Dyspnea was the most common clinical pictures. Bloody effusion fluids were noted in 10 patients. Moreover, the lymphocytic fluids were present in 78% of all patients. The neutrophilic fluids tended to have a bloody color, and there was progress to constrictive pericarditis even for those on anti-tuberculous chemotherapy. Five patients with subsequent constrictive pericarditis received pericardiectomy within 3.5 months of admission. Three of them received pericardiectomy later, despite pericardial window procedure. CONCLUSIONS: Follow-up by echocardiogram is necessary within three months after commencing medical treatment because of the high incidence of progression constrictive pericarditis despite aggressive medical treatment. Pericardiectomy seems to be the only solution to the catastrophic outcome of constrictive pericarditis.

Adolescent↗

PubMed1996

Adenomyomatosis of the gallbladder.

BACKGROUND: Adenomyomatosis of the gallbladder in Chinese patients has rarely been analyzed. METHODS: The clinical, radiological and pathological features of 18 patients with histologically-proven adenomyomatosis, collected during a 5-year period, were retrospectively analyzed. RESULTS: According to the extent and site of involvement, adenomyomatosis of the gallbladder was conventionally classified into three types: localized, generalized and segmental. In our series, the disease was localized in 17 patients (15 in the fundus and 2 in the neck), generalized in one patient and segmental in none. Only 5 patients showed sonographic features correlative to pathologic findings, and 2 of them were correctly diagnosed before operation. Only mild nonspecific abnormalities of liver function test or urine analysis were noted in some patients with gallbladder adenomyomatosis. The clinical manifestations were not related to coincidental diseases in 11 patients. All these 11 patients, with gallstone in 9 and without in 2, complained of epigastralgia, right upper quadrant abdominal pain or dyspepsia, which relieved all after cholecystectomy. CONCLUSIONS: Some patients with adenomyomatosis may be symptomatic and relieved by cholecystectomy. In patients with adenomyomatosis of the gallbladder and right upper quadrant pain of abdomen without other explanation, cholecystectomy may be considered. Infrequent accurate diagnosis in Chinese patients calls for a high suspicion of the disease entity in clinical practice.

Adenomyoma↗

PubMed1996

Reproducibility of the first-phase insulin release in the intravenous glucose tolerance test.

Insulin-dependent diabetes mellitus (IDDM) is a slowly progressive autoimmune disease. In the prediabetic phase of IDDM, the intravenous glucose tolerance test (IVGTT) demonstrates a progressive decline in the first-phase insulin response. The first-phase insulin response to intravenous glucose may enable individuals at risk of IDDM to be identified and preventive therapy to be instituted. However, the reproducibility of the first-phase insulin response is controversial. The aim of this study was to determine the variability of the first-phase insulin response to intravenous glucose. Ten healthy normal volunteers underwent two IVGTT within a 1 week interval, using the Islet Cell Antibody Register User's Study (ICARUS)-recommended standard protocol. The first-phase insulin response to intravenous glucose was expressed as the sum of the 1- and 3-minute insulin concentrations (muU/mL) and the total 0 to 10 minute insulin area under the curve (muU.min.mL-1). Variability was represented by the coefficient of variation (CV). The within-subject median CV was 21.2% for the sum of the 1- and 3-minute insulin concentrations and 23.9% for the total 0 to 10 minute insulin area under the curve. In conclusion, the reproducibility of the first-phase insulin response to intravenous glucose is poor. Hence, caution should be exercised when the IVGTT is applied to prediabetic IDDM patients for longitudinal study.

Adult↗

PubMed1996

Bipyridyl dihydrochloride inhibits tumor necrosis factor-alpha secretion by human keratinocytes on ultraviolet irradiation.

Paraquat manufacturers in Taiwan have been found to develop solar lentigo, actinic keratosis, as well as skin cancer in sun-exposed areas. Bipyridine has been found to be the responsible agent. At present, the mechanism for the pathogenesis of bipyridine-induced skin cancer is not known and it may be multifactorial. We investigated possible alterations in tumor necrosis factor (TNF)-alpha secretion in keratinocytes treated with 4,4'-bipyridyl dihydrochloride in vitro. Normal human keratinocytes were cultured and treated with bipyridine (10 micrograms/mL) or ultraviolet B (UVB) light (10 mJ/cm2), or with a combination of both. Bipyridine treatment alone resulted in a significant reduction in constitutive TNF-alpha secretion. Furthermore, in contrast to the finding in normal keratinocytes, UVB irradiation failed to promote TNF-alpha secretion in bipyridine-primed keratinocytes.

Humans↗

PubMed1996

Clinical significance of complements in ascitic diseases: elevated complement levels disapproving the liver disease origin.

In a two-year period, ascitic fluid concentrations of complement 3c and complement 4 were measured in 110 patients with sterile cirrhotic ascites, 31 patients with spontaneous bacterial peritonitis, 65 patients with hepatocellular carcinoma, 36 patients with peritoneal carcinomatosis and 12 patients with miscellaneous diseases (nephrotic syndrome 4, systemic lupus erythematosus 3, secondary peritonitis 2, cardiac ascites 1, eosinophilic peritonitis 1 and tuberculosis peritonitis 1) to assess the clinical utility of ascitic fluid complements. The ascitic fluid level of complements 3c or C4 was significantly higher in patients with peritoneal carcinomatosis (32.8 +/- 10.2, 13.4 +/- 7.4 mg/dL) than in patients with sterile cirrhotic ascites (9.2 +/- 5.2, 4.5 +/- 3.9 mg/dL, p < 0.001), spontaneous bacterial peritonitis (8.2 +/- 4.1, 3.8 +/- 2.4 mg/dL, p < 0.001) or hepatocellular carcinoma (12.8 +/- 8.3, 5.6 +/- 4.4 mg/dL, p < 0.001). However, it was not significantly different from the miscellaneous disease group. To verify that ascites formation is not related to liver disease origin, diagnostic sensitivity, specificity and accuracy were 83.3%, 92.7% and 90.9%, respectively, by the ascitic fluid level of complement 3c higher than the cut-off value (20 mg/dl); or 60.4%, 89.8% and 84.3%, respectively, by the ascitic fluid level of complement 4 higher than the cut-off value (10 mg/dL). A direct correlation was found between the ascitic fluid protein level and the ascitic fluid complement 3c (r = 0.70) or complement 4 (r = 0.57) level. Based on results in this study, we can conclude that measuring ascitic fluid complements is clinically useful in disapproving the liver disease origin of ascites formation. However, it is of little value in diagnosing spontaneous bacterial peritonitis or hepatocellular carcinoma.

Ascites↗

PubMed1996

Continence and rectoanal sphincteric inhibitory reflex after posterior sagittal anorectoplasty.

Rectoanal sphincteric inhibitory reflex and continence were evaluated in 23 patients with high and intermediate imperforate anus who underwent posterior sagittal anorectoplasty from 1985 to 1993. The postoperative anorectal function was followed both manometrically and clinically at regular intervals. The presence of the reflex was positively related to postoperative continence in patients older than 4 years but not in younger patients. Two patients with a rectoprostate fistula after an internal sphincter saving procedure had unsatisfactory results. Seven of nine patients with a blind rectal pouch, whose distal rectal end (where the internal sphincter lies) was partially excised or trimmed during reconstruction, had fair postoperative defecation. The internal sphincter saving procedure is helpful but it does not seem essential for the development of continence. The fact that patients with a negative reflex turned out to have a positive reflex 7 to 33 months after the initial test suggested that the rectum or perirectal tissue had recovered from surgical trauma. Time and age are important factors in clinical evaluation and interpretation of manometric results.

Anal Canal↗

PubMed1996

Comparison of continuous step-and-shoot versus step-and-shoot acquisition SPECT.

UNLABELLED: This study compared the quality of SPECT images obtained with step-and-shoot mode (SSM) and continuous step-and-shoot mode (CSSM). METHODS: Computer simulations of SSM and CSSM were performed with a two-dimensional Shepp-Logan head phantom and a high-resolution parallel-hole collimator. The effects of noise and photon attenuation were examined. RESULTS: Without noise and without attenuation, small structures in reconstructed images obtained using fast CSSM (less than 4 sec per view plus the moving time from one view to the next) were slightly blurred and rotated in the opposite direction of detector motion. With both noise and attenuation, these artifacts were not visible, and the image quality obtained from CSSM, especially from fast CSSM, was improved as compared to that resulting from the corresponding SSM due to the increasing number of counts. The improvement of image quality became less significant with increasing acquisition time and in the presence of attenuation. CONCLUSION: For fast SPECT, CSSM provided better image quality than the corresponding SSM, especially when attenuation effects were not present. For relatively long time SPECT without attenuation compensation that is typical for clinical studies, the image quality of CSSM was similar to that of SSM.

Computer Simulation↗

PubMed1996

Intentional replantation of a mandibular molar with calcified canal: a case report.

Intentional replantation is an accepted endodontic technique for treating teeth in which both conventional and/or surgical endodontic treatments are not recommended. A rare case using intentional replantation technique on one mandibular molar has been successfully treated. This procedure was used owing to inaccessible calcified canal and pain intolerance of the patient. A thirty month post-operative evaluation revealed an asymptomatic, functional tooth with no radiographic signs of pathosis. The favorable results obtained in this case might be attributed to certain factors, such as occlusal adjustment prior to replantation, maintaining asepsis during replantation, no-damaging pressure during extraction, use of noneugenol periodontal packing, preservation of the vitality of the periodontal ligament, a minimal extraoral period, non-rigid splinting, apicoectomy and retrograde amalgam filling were done for hermetic apical seal. Intentional replantation may be limited to those cases when conventional endodontic therapy is not possible, but may be a treatment alternative to maintain the dentition and save an otherwise hopeless tooth.

Adult↗

PubMed1996

Sequential hemodynamic changes for large volume paracentesis in post-hepatitic cirrhotic patients with massive ascites.

Large volume paracentesis (4.8 to 15.5 liters) was performed in 42 patients with post-hepatitic cirrhosis and massive ascites, not only to derive parameters capable of predicting the development of severe clinical hypotension after large volume paracentesis, but also to determine the optimal time to introduce preventive volume expanders. Systemic hemodynamics were sequentially measured for 72 hours in thirty-two patients. Severe clinical hypotension occurred in 13 (31.0%) patients 4-62 hours from the start of paracentesis. Univariate analysis, with the Mantel-Cox test used to compare Kaplan-Meier curves, and the subsequent multivariate analysis by stepwise Cox regression procedure were utilized to identify two variables, withdrawn ascitic fluid greater than 7.5 liters (p = 0.0121) and the absence of peripheral edema (p = 0.0148), reaching statistical significance to predict the occurrence of severe clinical hypotension. Compared to the baseline value, the cardiac output of patients not developing severe clinical hypotension increased (6.26 +/- 0.66 vs. 6.65 +/- 0.69 liter/min, p < 0.01) one hour from the start of paracentesis and right atrial pressure decreased (11.2 +/- 2.4 vs. 8.7 +/- 2.3 mmHg, p < 0.05). The cardiac output returned to the baseline value at the 9th hour. Based on the results presented herein, we can conclude that severe clinical hypotension occurs in a high percentage of patients with post-hepatitic cirrhosis and massive ascites within 72 hours from the start of large volume paracentesis. At potential risk of this occurring are those patients without peripheral edema and withdrawn ascitic fluid greater than 7.5 liters. Volume expanders should be introduced before 4th hour from the start of large volume paracentesis.

Adult↗

PubMed1996

[Cardiac arrest during transurethral resection of the prostate].

Due to the development of anesthetic drugs and techniques, and the progress of monitor system. The rate of cardiac arrest during anesthesia has declined during the last decades. We report two cases of sudden cardiac arrest which happened during transurethral resection of the prostate, and discuss the mechanism, treatment, and the methods of prevention.

Adult↗

PubMed1996

The comparative potency of intravenous nicardipine and verapamil on the cardiovascular response to tracheal intubation.

BACKGROUND: Two different types of calcium channel blockers (namely nicardipine and verapamil) have been used widely in clinical practice. However, no clinical studies have previously been performed to ascertain the relative potency of intravenous verapamil and nicardipine in the attenuation of cardiovascular response to tracheal intubation. METHODS: We assessed the optimal dose and relative potency of verapamil and nicardipine in the attenuation of hemodynamic response to tracheal intubation in 135 healthy patients. Control group (Group D received normal saline i.v. Patients in Groups II-V received nicardipine 0.005, 0.01, 0.03 and 0.06 mg/kg i.v., respectively. Patients in Groups VI-IX received verapamil 0.03, 0.05, 0.1 and 0.15 mg/kg i.v., respectively. Anaesthesia was induced with propofol (2.5 mg/kg) and muscle relaxation was facilitated by vecuronium (0.2 mg/kg, i.v.). One min after induction, tracheal intubation was performed. Mean arterial pressure (MAP) was measured at 1 min interval from 10 min before induction to 15 min after induction. RESULTS: The ED50 with 95% confidence interval of nicardipine and verapamil for the attenuation of 50% mean arterial pressure (MAP) increase after tracheal intubation were 14.55 micrograms/kg (8.25-25.67) and 75.4 micrograms/kg (58.7-96.95), respectively. The ED50 with 95% confidence interval of verapamil for the reduction of the 50% heart rate (HR) increase post tracheal intubation was 57.4 micrograms/kg (18-182.2). No differences were found in the frequency of perioperative arrhythmia, post-operative hypotension, postoperative emesis, dizziness, muscle weakness and muscle soreness within two hours following surgery, when compared control with experimental groups (p > 0.05). CONCLUSIONS: These results suggest that verapamil and nicardipine attenuate the hypertensive response to tracheal intubation without significant adverse effects in healthy patients. The dose ratio (ED50 nicardipine and ED50 verapamil for MAP) with 95% confidence interval was revealed to be 2.3 (1.82-7.41).

Adult↗

PubMed1995

Adverse life events and breast cancer: case-control study.

OBJECTIVE: To investigate the strength of association between past life events and the development of breast cancer. DESIGN: Case-control study. A standardised life events interview and rating was administered before a definitive diagnosis. SETTING: Breast Cancer Screening Assessment Unit and surgical outpatient clinics at King's College Hospital, London. SUBJECTS: 119 consecutive women aged 20-70 who were referred for biopsy of a suspicious breast lesion. MAIN OUTCOME MEASURES: Odds ratio of the risk of developing breast cancer after life events in the preceding five years after adjustment for confounders. RESULTS: 41 women were diagnosed as having malignant disease while the remainder had benign conditions. Severe life events increased the risk of breast cancer. The crude odds ratio was 3.2 (95% confidence interval 1.35 to 7.6). After adjustment for age and the menopause and other potential confounders this rose to 11.6 (3.1 to 43.7). Multiple logistic regression analysis showed that all severe events and coping with the stress of adverse events by confronting them and focusing on the problems significantly predicted a diagnosis of breast cancer. Non-severe life events and long term difficulties had no significant association. CONCLUSION: These findings suggest an aetiological association between life stress and breast cancer.

Adaptation, Psychological↗

PubMed1995

A P2X purinoceptor expressed by a subset of sensory neurons.

ATP is known to depolarize sensory neurons, and may play a role in nociceptor activation when released from damaged tissue. Here we report the molecular cloning and characterization of a new member of the P2X receptor family, P2X3, expressed by these cells. The channel transcript was present in a subset of rat dorsal-root-ganglion sensory neurons, some of which express nociceptor-associated markers; it was absent in other tissues that were tested, including sympathetic, enteric and central nervous system neurons. Moreover, when expressed in Xenopus oocytes, the channel showed an ATP-dependent cation flux. P2X3 is the only ligand-gated channel known to be expressed exclusively by a subset of sensory neurons. The remarkable selectivity of expression of the channel coupled with its sensory neuron-like pharmacology suggests that this channel may transduce ATP-evoked nociceptor activation.

Amino Acid Sequence↗