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Biomedical subjects

C C Yang

Publications and source records attributed to C C Yang.

353 records · Page 20Linked to original sources
PubMedDate not supplied

The natural history (fading time) of stigmata of recent hemorrhage in peptic ulcer disease.

From October 1991 to December 1992, 144 patients with bleeding peptic ulcer and stigmata of recent hemorrhage were included in a study designed to investigate, by means of endoscopic examinations repeated at 2-day intervals, the evolutionary development of stigmata of recent hemorrhage, such as visible vessels, and to determine the time required for each type of stigma to fade. Eighty-five patients underwent endoscopic follow-up until the stigmata had disappeared. A visible vessel takes about 4.1 +/- 2.1 days to disappear, requiring significantly more time than an adherent clot or an old stigma, which take 2.4 +/- 0.8 days and 2.4 +/- 1.3 days, respectively (p < .05). Bleeding does not recur after stigmata disappear. Time required for stigmata to fade is not affected by age, sex, smoking, history of peptic ulcer, ulcer location, severe bleeding, underlying systemic disease, or endoscopic local therapy. While healing, stigmata of recent hemorrhage evolve through a sequence of phases: a visible vessel may or may not appear as an adherent clot and then as a red or black flat spot before disappearing.

Endoscopy, Gastrointestinal↗
PubMedDate not supplied

Myocardial tissue characterization based on a polarization-sensitive optical coherence tomography system with an ultrashort pulsed laser.

A polarization-sensitive optical coherence tomography (PSOCT) system using a femtosecond-laser as the broadband light source is implemented with the axial resolution of 5 microm in free space. Through the design of path-length difference between the two polarization inputs and the modulation of one of the polarization inputs, the PSOCT images of various input and output polarization combinations can be distinguished and simultaneously collected. The PSOCT system is then used for in vitro scanning of the myocardium tissues of normal and infarcted rat hearts. The destruction of the birefringence nature of the fiber muscle in the infarcted heart can be clearly observed.

Animals↗
PubMedDate not supplied

Association between seropositivity of antibodies against hepatitis a virus and Helicobacter pylori.

Helicobacter pylori and hepatitis A virus (HAV) are documented to share common transmission routes including fecal-oral. This study examined the association between seropositivity of antibodies against H. pylori (anti-HP) and HAV (anti-HAV) via a community-based survey of 40 randomly selected kindergartens in 10 urban and 10 rural areas. Serum samples from 2,047 healthy preschool children and 104 teachers were screened for anti-HP by enzyme-linked immunosorbent assay, and for anti-HAV by microparticle enzyme immunoassay. In children, a low prevalence of anti-HAV (0.44%) was found, in contrast to a high prevalence in their teachers (78.8%); anti-HP seroprevalence was 6.4% for children and 30.8% for teachers. Anti-HAV and anti-HP seropositivities were significantly associated in teachers after adjustment for age, sex, and residential area through multiple logistic regression analysis (multivariate-adjusted odds ratio = 7.3; 95% confidence interval [CI] = 1.4-36.8, P < 0.001). Our findings suggest that HAV and H. pylori may have shared transmission routes in central Taiwan 15 years or more ago, but not any recently.

Adult↗
PubMedDate not supplied

Role of upright chest radiography and ultrasonography in demonstrating free air of perforated peptic ulcers.

BACKGROUND/AIMS: The purpose of this study was to determine the value of upright chest radiography and ultrasonography in demonstrating free air of perforated peptic ulcers. METHOLOGY: Eighty-four patients with perforated peptic ulcers receiving both upright chest radiography and ultrasonography before laparotomy. The sensitivity of each modality in demonstrating free air was correlated. RESULTS: Among the 84 patients receiving both examinations, free air was demonstrated in only 39 (46%) upright chest radiographs and 46 (55%) ultrasonographs, the direct sign could be demonstrated in 57 (68%) patients by combined radiography and ultrasonography. Besides, the indirect sign of ascites could be demonstrated in 26 (31%) ultrasonographs. CONCLUSIONS: Ultrasonography is more sensitive than upright chest radiography to demonstrate free air of perforated peptic ulcers, and it should be considered in those patients of suspected perforated peptic ulcers with negative upright chest radiography. Combined methods of upright chest radiography and ultrasonography can increase the overall sensitivity in demonstrating free air.

Adolescent↗
PubMedDate not supplied

The features of perforated peptic ulcers in conventional computed tomography.

BACKGROUND/AIMS: CT is not usually of priority to evaluate the pathology of the gastrointestinal tract, especially perforated peptic ulcer. However CT might be employed when the presentation is atypical. The study was to summarize the imaging features of perforated peptic ulcer in conventional CT and assess its ability of detecting perforated peptic ulcer. METHODOLOGY: The CTs of 14 consecutive patients with perforated peptic ulcer confirmed by operation were retrospectively reviewed. The CTs were obtained after intravenous contrast medium, but oral contrast medium was administered only in 5 patients. The CT findings were correlated with surgical findings. RESULTS: Among these 14 patients, all the 14 patients (100%) had extraluminal air accumulation, 10 patients (71%) had abnormal fluid accumulation, and 5 (36%) patients had inflammatory changes in surrounding soft tissues. In addition, conventional CT could only demonstrate the site of perforation in 5 patients (36%) of them. CONCLUSIONS: Conventional CT was valuable in the diagnosis of perforated peptic ulcer, and pneumoperitoneum was the most common feature. However the ability of conventional CT in localizing the site of perforation was poor.

Adult↗
PubMedDate not supplied

The accuracy of endoscopic ultrasound, endoscopic retrograde cholangiopancreatography, computed tomography, and transabdominal ultrasound in the detection and staging of primary ampullary tumors.

BACKGROUND/AIMS: To compare the accuracy between EUS (endoscopic ultrasound), ERCP (endoscopic retrograde cholangiopancreatography), CT (computed tomography), and transabdominal US (ultrasound) in the detection and staging of primary ampullary tumors. We will also try to discuss the influence of endobiliary stent on EUS in staging ampullary tumors. METHODOLOGY: Twenty-one patients with ampullary tumors were evaluated by EUS, ERCP, CT, and US before operation. The accuracy was assessed with TNM staging and compared with the surgical-pathological findings. RESULTS: EUS was superior to CT and US in detecting ampullary tumors, but EUS and ERCP are of similar sensitivity (EUS 95%, ERCP 95%, CT 19%, US 5%). EUS was superior to CT and US in T staging (EUS 75%, CT 5%, US 0%) and detecting lymph node metastasis (EUS 50%, CT 33%, US 0%) of ampullary tumors. The accuracy of EUS in T and N staging of ampullary tumors tended to be decreased in the presence of endobiliary stent (stenting: T 71%, N 75%; nonstenting T 83%, N 100%), but there was no statistical significance. CONCLUSIONS: EUS was superior to CT and US in assessing primary ampullary tumors, but it was not significantly superior to ERCP in detecting ampullary tumors. The presence of endobiliary stent may decrease the accuracy of EUS in staging ampullary tumors.

Aged↗
PubMedDate not supplied

Comparison of technetium-99m tetrofosmin and gallium-67 citrate scintigraphy for detecting malignant lymphoma.

The aim of this study was to compare the value of technetium-99m tetrofosmin (Tc-TF) scintigraphy with that of gallium-67 citrate (Ga-67) scintigraphy for detecting malignant lymphoma. In this study, 50 patients with malignant lymphoma underwent Tc-TF and Ga-67 scintigraphy before receiving any therapy. Tc-TF scintigraphy detected malignant lymphoma in 44 (88%) patients, but was false-negative in 4 cases of infradiaphragmatic malignant lymphoma and in 2 cases of malignant lymphoma with chemotherapy resistance. Ga-67 scintigraphy detected malignant lymphoma in 45 (90%) patients, but was false-negative in 3 cases of low-grade non-Hodgkin's lymphoma and in 2 cases of malignant lymphoma with bone marrow involvement. There was no significant difference in sensitivity between Tc-TF and Ga scintigraphy. However, a combination of Tc-TF and Ga-67 scintigraphy detected malignant lymphoma in all 50 patients (100%). We conclude that it is necessary to combine Tc-TF and Ga-67 scintigraphy to accurately detect malignant lymphoma.

Adult↗
PubMedDate not supplied

[Staphylococcus aureus endocarditis with large vegetation and emboli: report of a case].

A 12-year-old boy with infective endocarditis caused by staphylococcus aureus is reported. The patient suffered from intermittent high fever for 10 days. Physical examination revealed a grade II/VI systolic murmur at apex, conjunctival petechiae, and Janeway lesions over palms and soles. Three sets of blood culture were done immediately, and staphylococcus aureus was grown from all. Echocardiograms showed an increased thickness of anterior mitral leaflet, and a vegetation with 2.2 cm in diameter was found in left atrium. Aortograms revealed total occlusion of abdominal aorta and superior mesenteric artery. Emergent operation of abdominal aorta was done, a bacterial embolus was taken out, measuring 5-6 cm in length. Seven days after operation, cerebral hemorrhage occurred, and the patient expired 8 more days later.

Aorta, Abdominal↗
PubMedDate not supplied

Neurobiology of central angiotensin III and dipsogenesis.

This review provides a synopsis of the physiologic role of central angiotensin III (AIII), the biologically active degradative product of angiotensin II, in dipsogenesis. The integrity of the central noradrenergic system is essential to the elicitation of polydipsia by AIII. It is conceivable that synaptically released norepinephrine may act on the alpha 1-adrenoceptors to potentiate the drinking response to the heptapeptide. This release, however, may be subjected to a tonic inhibition by the alpha 2-adrenoceptors. Chronic intracerebroventricular administration of AIII fails to produce sustained drinking behavior in spontaneously hypertensive rats. Behavioral and electrophysiologic observations suggest that this is because of the development of early desensitization of at least the angiotensin receptors at the subfornical organ, a major target site for AIII-induced dipsogenesis. This process is exacerbated by a suggested dysfunction of the central degradative enzyme for AIII in this strain of rat. Recent results suggest that it is likely that neurons in the caudal hypoglossal nucleus may serve as the final common pathway for AIII-induced drinking response. Furthermore, an excitatory link between the nucleus reticularis gigantocellularis in the medulla oblongata and caudal hypoglossal nucleus may form part of the descending neural pathways that mediate the dipsogenesis elicited by AIII. It is evident that AIII in the brain participates actively in at least the initiation and consummatory phases of water homeostasis. Thus, apart from directly acting on the central machinery for circulatory control, AIII may also influence cardiovascular functions by affecting cardiac output via regulation of fluid volume.

Angiotensin III↗
PubMedDate not supplied

Bioflavonoids commonly and potently induce tyrosine dephosphorylation/inactivation of oncogenic proline-directed protein kinase FA in human prostate carcinoma cells.

In this study, we investigate the effect of bioflavonoids on the activity and phosphotyrosine content of oncogenic proline-directed protein kinase FA (PDPK FA) in human prostate carcinoma cells. Chronic treatment of human prostate carcinoma cells with low concentrations of quercetin, apigenin, and kaempferol commonly and potently induced tyrosine dephosphorylation and concurrent inactivated oncogenic PDPK FA in a concentration-dependent manner. This is demonstrated by a specific assay of this kinase's activity in the immunoprecipitates from the cell extracts followed by immunoblotting and phosphotyrosine analysis. The results indicate that bioflavonoids may function as common tyrosine kinase inhibitors to inhibit PDPK FA-specific tyrosine kinase and thereby to induce tyrosine dephosphorylation/inactivation of this oncogenic kinase in human carcinoma cells. Under this condition, quercetin, apigenin, and kaempferol can also inhibit cell growth in a similar concentration-dependent manner. The results further indicate that inhibition of tyrosine phosphorylation/activation of this oncogenic PDPK represents a new mode of action mechanism for bioflavonoids during the antiproliferation process in human carcinoma cells.

Flavonoids↗