Search PubMed⌕ Search

Biomedical subjects

K J Chang

Publications and source records attributed to K J Chang.

At least 91 records · Page 5Linked to original sources
PubMed1997

Endosonography-guided fine-needle aspiration biopsy: diagnostic accuracy and complication assessment.

BACKGROUND & AIMS: Endosonography-guided fine-needle aspiration biopsy (EUS-FNA) permits cytological confirmation of EUS findings. A multicenter prospective evaluation of EUS-FNA for primary diagnosis, staging, and/or follow-up purposes was undertaken. METHODS: EUS-FNA was performed in 457 patients with 554 lesions. Clinical (n = 218) or histopathologic (n = 256) confirmation was available in 192 lymph nodes, 145 extraluminal masses, 115 gastrointestinal wall lesions, and 22 cystic lesions. RESULTS: EUS-FNA sensitivity, specificity, and accuracy was 92%, 93%, and 92% for lymph nodes, 88%, 95%, and 90% for extraluminal masses, and 61%, 79%, and 67% for gastrointestinal wall lesions, respectively. The sensitivity and accuracy for lymph nodes and extraluminal masses was superior to that for gastrointestinal wall lesions. When EUS-FNA was compared with EUS size criteria in lymph node evaluation, specificity (93% vs. 24%) and accuracy (92% vs. 69%) were superior, whereas sensitivity (92% vs. 86%) was similar. The accuracy of EUS-FNA in patients with previously failed biopsy procedures was 81% (73 of 90). Five nonfatal complications occurred for a rate of 0.5% (95% confidence interval, 0.1%-0.8%) in solid lesions vs. 14% (95% confidence interval, 6%-21%) in cystic lesions. CONCLUSIONS: EUS-FNA accurately and safely evaluates solid peri-intestinal lesions and improves lymph node staging accuracy.

Abdomen↗
PubMed1997

The clinical utility of endoscopic ultrasound-guided fine-needle aspiration in the diagnosis and staging of pancreatic carcinoma.

BACKGROUND: Endoscopic ultrasound (EUS) guided fine-needle aspiration (FNA) of pancreatic lesions is being increasingly used. Our aim was to determine the safety, accuracy, and clinical utility of EUS-guided FNA in both the diagnosis and staging of pancreatic cancer. METHODS: Forty-four patients (24 men/20 women) had EUS-guided FNA of pancreatic lesions (39 head/neck, 5 body, 3 tail) and/or associated lymph nodes. The mean age was 61 (range, 28 to 88 years). The indication for EUS-guided FNA was a pancreatic lesion seen initially on CT (39%), ERCP (43%), or EUS (18%). Follow-up data were collected on all patients for mean of 14.5 months (range 1 to 33 months). RESULTS: CT detected only 15 of 61 (25%) focal lesions seen by EUS, Adequate specimens were obtained by EUS-guided FNA in 44 of 47 (94%) pancreatic lesions and 14 of 14 (100%) associated lymph nodes (overall adequacy was 95%). Of the 46 lesions in which specimens were adequate and a final diagnosis was available (32 malignant, 14 benign), EUS-guided FNA had a sensitivity of 92%, specificity of 100%, and diagnostic accuracy of 95% for pancreatic lesions and 83%, 100%, and 88% for lymph nodes, respectively. Six percent of pancreatic cases had inadequate specimens and, if included, lowered the sensitivity to 83%, specificity to 80%, and diagnostic accuracy to 88% for pancreatic lesions. In 3 patients with enlarged celiac nodes on EUS, EUS-guided FNA was able to make a tissue diagnosis of metastasis, which changed the preoperative staging and precluded surgery. EUS in combination with EUS-guided FNA precluded surgery in 12 of 44 (27%) and may have precluded surgery in an additional 6 of 44 (14%). EUS-guided FNA avoided the need for further diagnostic tests, thus expediting therapy in a total of 25 (57%) patients and influenced clinical decisions in 30 of 44 (68%) patients. The estimated cost savings based on surgeries avoided was approximately $3300 per patient. There was only one complication (2%), a post-FNA fever. CONCLUSION: EUS-guided FNA of the pancreas appears to be a safe and effective method that increases both the diagnostic and staging capability of EUS in pancreatic cancer. The clinical impact of EUS-guided FNA includes avoiding surgery and additional imaging studies with a substantial cost savings.

Adult↗
PubMed1997

Studies on the serological cross-reaction between dengue and Japanese encephalitis.

Antibody responses of sero-confirmed flavivirus-infected patients were investigated by hemagglutination-inhibition (HI) tests against acute phase sera (S1) and convalescent phase sera (S2) using JE virus (JEV) JaGAr# 01 strain antigen (J-Ag) and dengue virus (DV) type 1 Hawaiian strain antigen (D-Ag). Analysis of the test results showed that depending on the combinations of HI responses to both antigens, the sero-confirmed patients could be divided into five classes: primary JE, secondary JE, primary D (JEV-uncontracted), primary D(JEV-contracted), and secondary D(JEV-contracted) patients. The diagnostic combinations of responses to HI tests for the infections were discussed and defined in this paper.

Animals↗
PubMed1997

Endoscopic ultrasound-guided fine-needle aspiration biopsy and interventional endoscopic ultrasonography. Emerging technologies.

Endoscopic ultrasonography (EUS) has been shown to be useful in the detection and staging of gastrointestinal and pancreatic malignancies. However, EUS has some limitations including suboptimal specificity in lymph node staging. This is one factor that has curtailed its widespread use. The emergence of EUS-guided fine-needle aspiration (FNA) and other interventional applications of EUS appear likely to increase the clinical utility and cost-effectiveness of this modality. This article reviews recent literature describing the role of EUS in guiding FNA, detecting choledocholithiasis and assisting in interventions such as pseudocyst drainage.

Biopsy, Needle↗
PubMed1997

Immunohistochemical analyses of p53 protein expression in breast cancers in Taiwan: a clinicopathologic study.

Immunohistochemical analysis of the p53 protein was performed on paraffin sections of tumor tissue from 210 breast cancer patients. All patients had a follow-up period of more than 5 years. Protein expression of p53 was detected in 64 patients (30.5%). There was significant correlation between p53 protein expression and a high histologic grade (grade II vs grade I/II, 49% vs 23.6%, p = 0.0008) and high mitotic index (> or = 10/10 hpf vs < 10/10 hpf, 42.9% vs 19.6%, p = 0.0004), but not with axillary node status, stromal lymphocytic infiltration, or estrogen receptor or progesterone receptor status. We found that p53 protein expression was not a significant factor in predicting 5-year mortality.

Adult↗
PubMed1997

Antagonistic modulation between the delta opioid agonist BW373U86 and the mu opioid agonist fentanyl in mice.

This study was performed to assess the interactions that occur between delta- and mu opioid receptors by studying effects of the systemically active nonpeptide delta agonist BW373U86 and the mu agonist fentanyl in mice. Concentrations of the compounds were varied, and analgesic responses were determined by 55 degrees C hot-plate assays. BW373U86 produced hot-plate antinociceptive activity along with convulsive side effects. These effects could be antagonized by the selective delta antagonist naltrindole. Fentanyl produced hot-plate antinociceptive activity with Straub tail and hyperactivity as side effects. When BW373U86 and fentanyl were coadministered, BW373U86 convulsive activity was attenuated by fentanyl in a dose-dependent manner and the fentanyl-induced Straub tail effect was antagonized by BW373U86, also in a dose-dependent manner. Hot-plate analgesic activity was additive between the two compounds. The delta antagonist naltrindole partially antagonized the ability of BW373U86 to block the fentanyl-induced Straub tail effect. The mu antagonist beta-funaltrexamine antagonized the fentanyl-induced blockade of the convulsive effects of BW373U86. These data suggest that complex inhibitory interactions take place between mu and delta receptors in mice. Future studies are clearly needed to study the neuromodulatory effects of mu and delta receptors. The widespread use of mu agonists in the clinic indicates that a large number of patients exist who could greatly benefit from the conjunctive use of delta pharmaceuticals.

Analgesics, Opioid↗
PubMed1997

Endoscopic removal of nasogastric tube sutured unintentionally to gastrojejunostomy.

A nasogastric tube mistakenly sutured to the anastomotic site is a rare surgical error during gastrointestinal operation. When it does happen, proper management will prevent subsequent complications. If resistance is experienced when pulling the nasogastric tube after gastrointestinal surgery, it should never be pulled more forcefully. The endoscope should be introduced to document the etiology and to provide treatment after 2 weeks postoperation based on the wound healing process and strength of suture materials.

Endoscopy↗
PubMed1997

Flat adenoma of the colon: two cases.

Flat adenoma has been frequently reported to have a higher potential for malignant change than other polypoid adenomas. It is an endoscopically visible sessile lesion that consists histologically of an adenomatous change of the colonic mucosa. Detection, diagnosis, and treatment of flat adenoma has not previously been reported in Taiwan. We found such lesions in two patients during colonoscopic examinations as patches of discolored and irregular mucosa. Histopathologic studies revealed adenomas with mild to moderate dysplasia. Patient 1 underwent segmental colectomy; patient 2 underwent an endoscopic strip biopsy. Focal malignant changes were noted in patient 1. Both patients received close follow-up at the outpatient clinic. No recurrence has been seen in patient 1. Patient 2 developed an enlarged sessile lesion with a histologic picture showing a tubular adenoma without malignancy but refused further surgical treatment. This paper outlines the endoscopic and pathologic characteristics of flat adenoma in two patients, and should alert physicians to the importance of early detection and treatment of this lesion.

Adenoma↗
PubMed1996

Binding of [3H](+)-BW373U86 to delta-opioid receptors in rat brain membranes.

A tritiated form of the non-peptide delta-opioid receptor agonist (+)-BW373U86 ((+)-4-((alpha-R)-alpha-((2S,5R)-4-allyl-2, 5-dimethyl-l-piperazinyl)-3-hydroxybenzyl)-N,N-diethylbenzamide) was synthesized and its binding characteristics studied. [3H](+)-BW373U86 bound with subnanomolar affinity to rat brain membranes and was displaced most effectively by ligands selective for delta-opioid receptors. Naltrindole, naltriben, and 7-benzylidenenaltrexone exhibited apparent inhibition constants of 0.06, 1.54, and 4.49 nM, respectively, while mu- or kappa-selective ligands showed little affinity for this site. [3H](+)-BW373U86 binding was sensitive to the presence of guanine nucleotides; GDP caused a 3-fold decrease and 5'-guanylyl-imidodiphosphate (Gpp[NH]p) caused a 25% increase in binding affinity.

Animals↗
PubMed1996

The altered activity of membrane-bound protein kinase C in human liver cancer.

The activity of protein kinase C (PKC) in human liver cancer and adjacent normal liver tissue was determined. It was found that the activity of the membrane-bound PKC was significantly decreased in cancer tissue compared with that of the adjacent normal tissues (245.3 +/- 49.3 versus 396.9 +/- 82.4 pmol 32P/min per mg, P < 0.05); while the PKC activity in the cytosolic fraction was not significantly different (50.6 +/- 11.3 versus 40.0 +/- 6.6 pmol 32P/min per mg) concerning protein concentration. The reduced expression of membrane-bound PKC activity was observed at least in 8 of 9 patients. Moreover, the cancer tissue showed a significant decrease in total membranous PKC activity compared with the adjacent normal tissue of each patient (163.1 +/- 38.8 versus 433.8 +/- 92.4 pmol 32P/min per g tissue; P < 0.005) and no difference in total cytosolic PKC activity (285.9 +/- 58.8 versus 311.6 +/- 44.0 pmol 32P/min per g tissue). These results indicate that the progression of the human liver cancer might be associated with the decrease of membrane-bound PKC activity.

Adult↗
PubMed1996

Characterization of delta opioid receptors in lung cancer using a novel nonpeptidic ligand.

Cancer cells are often characterized by the presence of membrane receptors not normally associated with nontransformed cells from the same tissue type. Recent studies have demonstrated increased expression of high-affinity binding sites for opioid receptor-selective ligands in lung cancer cell lines relative to normal lung tissue. We investigated the binding of a nonpeptidic delta opioid receptor ligand in small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) cells with the aim of developing the ligand as a novel lung cancer imaging agent. The ligand, [3H] (+)-4-[alpha-R)-alpha-((2S,5R)-4-allyl-2,5-dimethyl-1-piperazinyl)-3- hydroxybenzyl)-N,N-diethylbenzamide ([3H](+)BW373U86), bound with high-affinity [Kd (dissociation constant) = 0.066 +/- 0.012 nM] to membranes prepared from six different SCLC cell lines but not to those from seven NSCLC cell lines, including one mesothelioma. The number of biding sites varied from 10 to 300 fmol/mg membrane protein. Competition binding studies demonstrated displacement of [3H](+)BW373U86 binding by the delta-selective antagonists naltriben and 7-benzylidenenaltrexone but not with the mu- and kappa- selective antagonists D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 and trans-(+/-)-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)cyclohexyl]ben zeneacetamide methanesulfonate. Mean apparent Kis for naltriben and 7-benzylidenenaltrexone in membranes from two SCLC cell lines were 0.17 and 3.9 nM, respectively, but were >10 microM for the mu and kappa ligands. The nonselective antagonist naloxone displaced [3H](+)BW373U86 binding with an apparent Ki of approximately 29 nM. On the basis of these data, we believe the lung cancer receptor to be similar, if not identical, to the human brain delta opioid receptor. The lack of high-affinity [3H](+)BW373U86 binding in normal mouse lung membranes suggests a potential role for this ligand as a novel therapeutic or imaging agent.

Animals↗
PubMed1996

Breast cancer vascularity: color Doppler sonography and histopathology study.

In this prospective study, the authors examined 50 patients with breast tumors (malignant, n = 32; benign, n = 18) to investigate the correlation between color Doppler flow mapping and histopathological findings and to evaluate the clinical significance of color Doppler mapping. Among the 32 patients with breast cancer, color Doppler signals were detected in 24 patients (75%). The maximum flow velocities varied from 5 to 34 cm/sec, with 16 (67%) of them above 15 cm/sec. Among the 18 patients with benign tumors, color Doppler signals could be detected in 7 (39%). The maximum flow velocity varied from 3 to 30 cm/sec but was over 15 cm/sec in only two patients (28%). Histological studies revealed that color Doppler signals detected by Doppler sonography correlated with disordered neovascularization penetrating the lesion from its periphery, consisting of thin-walled blood vessels and large arteriovenous shunts. Although large tumors tend to have high Doppler flow, there is no significant correlation between the maximum flow velocity and tumor size. There is also no significant correlation between the detection of high flow color Doppler signals and the age, receptor status, tumor size, lymph node metastases, or clinical stage of patients with breast cancer. However, there is a positive association (p < 0.05) between nodal metastases and higher tumor flow velocity in T1 (< or = 2 cm) breast tumors, but not in larger tumors. It is concluded that color Doppler is useful in the assessment of tumor vascularity but is of limited value in the differentiation of benign from malignant lesions. However, the presence of color Doppler signals in T1 breast cancer suggesting early dissemination of the cancer might be of important clinical significance in detecting those small, apparently early, but aggressive tumors with poor prognosis.

Adult↗
PubMed1996

Occult breast carcinoma--use of color Doppler in localization.

Occult breast carcinoma presenting with axillary metastases is a difficult clinical problem. Mammography is recommended as the diagnostic tool for detecting breast masses, but is very insensitive. In two consecutive patients with nonpalpable carcinoma of the breast, the detection of breast lesions was made by color Doppler sonography. The sensitivity of the technique makes it a useful diagnostic aid in patients with negative mammograms.

Adult↗
PubMed1996

Endoscopic ultrasound (EUS) and EUS-guided fine-needle aspiration of the left adrenal gland.

BACKGROUND: We reported the application of endoscopic ultrasound (EUS) and EUS-guided fine-needle aspiration (FNA) in the local staging of lung cancer. Up to 16% of patients with lung cancer may have adrenal masses. The role of EUS in the characterization of the adrenal gland, as well as EUS-guided FNA of the adrenal gland, has not been described. METHODS: The adrenal gland was characterized by EUS in 30 of 31 (97%) patients. EUS-guided FNA of an adrenal was performed in one patient. Anatomic correlation and ex vivo images were obtained. RESULTS: The average dimension was 2.5 cm (range 1.4 to 3.5) x 0.8 cm (range 0.3 to 1.4) with two morphologic types: "seagull" and "elliptical." One patient with lung cancer and a left adrenal mass with a nondiagnostic CT-guided FNA underwent EUS-guided FNA, which established the diagnosis of metastatic adenocarcinoma. Surgery was avoided. CONCLUSIONS: The left adrenal can be imaged by EUS in almost all patients. EUS-guided FNA may be useful when applied to left adrenal metastatic tumors for tissue diagnosis.

Adenocarcinoma↗