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Biomedical subjects

X Z Lin

Publications and source records attributed to X Z Lin.

At least 37 records · Page 2Linked to original sources
PubMed1999

Biliary sludge and pigment stone formation in bile duct-ligated guinea pigs.

We studied the effects of bile stasis in a guinea pig model of pigment gallstone. The common bile ducts of guinea pigs were partially ligated, and the guinea pigs killed one or two weeks later. Biliary sludge or stones were examined with the Fourier transform infrared spectroscopy and the scanning electromicroscopy. The bile was analyzed for pH, free calcium, bile acids and bilirubin fractions, and the activities of both bacterial and endogenous beta-glucuronidase. After bile duct ligation, calcium bilirubinate precipitates or stones formed in all except one of the animals studied. The bile pH and the proportion of unconjugated bilirubin rose after bile duct ligation, with a concomitant fall of bilirubin monoglucuronide. The activity of bacterial beta-glucuronidase decreased after ligation, while the activity of endogenous beta-glucuronidase rose at week 2. Our results imply that precipitation of calcium bilirubinate in this animal model was induced by an increased bile pH and the nonenzymatic hydrolysis of conjugated bilirubin.

Animals↗
PubMed1999

Interactive 3-D virtual colonoscopy system.

We describe a low-cost three-dimensional (3-D) virtual colonoscopy system that is a noninvasive technique for examining the entire colon and can assist physicians in detecting polyps inside the colon. Using the helical CT data and proposed techniques, we can three-dimensionally reconstruct and visualize the inner surface of the colon. We generate high resolution of video views of the colon interior structures as if the viewer's eyes were inside the colon. The physicians can virtually navigate inside the colon in two different modes: interactive and automatic navigation, respectively. For automatic navigation, the flythrough path is determined a priori using the 3-D thinning and two-pass tracking schemes. The whole colon is spatially subdivided into several cells, and only potentially visible cells are taken into account during rendering. To further improve rendering efficiency, potentially visible cells are rendered at different levels of detail. Additionally, a chain of bounding volume in each cell is used to avoid penetrating through the colon during navigation. In comparison with previous work, the proposed system can efficiently accomplish required preprocessing tasks and afford adequate rendering speeds on a low-cost PC system.

Automation↗
PubMed1999

The effects of bile duct obstruction on the biliary secretion of ciprofloxacin in piglets.

OBJECTIVE: The aim of this study was to evaluate the effect of bile duct obstruction on biliary secretion of ciprofloxacin and to look for useful parameters to guide clinical use of antibiotics in patients with acute cholangitis. METHODS: Twenty-five Landrace piglets were used in this study. Their common bile ducts were ligated, with a duration ranging from 1 to 7 days. The changes of liver biochemical tests, intrabiliary pressure, diameter of common bile duct, and concentration of ciprofloxacin in bile were compared among the piglets with different severity of bile duct obstruction. RESULTS: The bile-to-serum ratio of the ciprofloxacin concentration was 586.4% +/- 140.3% before the ligation of bile duct and was reduced significantly to 94.5% +/- 118.0% after 1-day obstruction. The biliary secretion of ciprofloxacin was greatly affected by the intrabiliary pressure in that the bile-to-serum ratio of ciprofloxacin concentration was reduced to 12.2% +/- 14.8% when the intrabiliary pressure reached to 32 cm H2O. The change in the intrabiliary pressure was correlated with the diameter of common bile duct, with a correlation coefficient of 0.90 (p < 0.001). CONCLUSIONS: Biliary secretion of ciprofloxacin is decreased in proportion to the increase of intrabiliary pressure. In obstruction, a markedly dilated common bile duct usually indicates high intrabiliary pressure, and thus biliary concentrations of antibiotics will be lower than expected. Hence, our observations suggest that choosing an antibiotic with high antimicrobial activity, or establishing a biliary drainage to lower the intrabiliary pressure, would be beneficial for patients suffering from cholangitis with a dilated biliary tree.

Animals↗
PubMed1998

The normal adult human liver biopsy: a quantitative reference standard.

In assessing adult human liver histology, questions remain concerning the normal number of portal tracts and bile ducts in a liver biopsy. We therefore reviewed liver biopsies obtained with use of a percutaneous Menghini cutting needle (14G, internal diameter 1.6 mm), from 16 patients undergoing liver biopsy for screening procedures (age 49 +/- 14 years, +/-SD) and found to be normal by histological examination. The average aggregate length of the liver tissue was 1.8 +/- 0.8 cm (area of 16.4 +/- 10.7 mm2), representing 7 +/- 3 tissue fragments. Portal triads containing at least one profile each of a portal vein, hepatic artery, and interlobular bile duct numbered 11 +/- 6 per biopsy (range 3-23). Portal dyads, which did not contain one of these profiles, usually the portal vein, numbered 8 +/- 5 (range 1-18). On a per-specimen basis, 38% of portal tracts did not contain a portal vein, 7% did not contain a bile duct, and 9% did not contain a hepatic artery. Because of multiplicity of profiles within portal tracts, however, the average number of profiles per portal tract was 6 +/- 5 (range 2-35). Notably, on average there were 2.3 +/- 2.2 interlobular bile ducts per portal tract, compared to 2.6 +/- 2.3 hepatic arteries and 0.7 +/- 0.7 portal veins. The average minimum external diameter of interlobular bile ducts was 13 +/- 4 microm, of hepatic arteries 12 +/- 5 microm, and of portal veins 35 +/- 25 microm. Bile ducts greater than 30 microm in diameter were rare, only one each in two biopsies were observed. In contrast, probable canals of Hering were occasionally evident at the periphery of portal tracts (6 +/- 6 per biopsy) and within the lobular parenchyma as strings of cuboidal cells (5 +/- 5 per biopsy). We conclude that, although multiplicity of profiles is normal, portal dyads are almost as common as portal triads in normal peripheral liver tissue. On average, there are two interlobular bile ducts, two hepatic arteries, and one portal vein per portal tract, with 6 full portal triads per linear cm of tissue obtained by external Menghini biopsy technique with use of a 14G needle, equivalent to 0.8 +/- 0.5 portal triads per mm2. By serving as a reference standard for adult human liver histology, these findings may assist in the histopathological assessment of liver biopsies, particularly those performed for disease conditions featuring loss of intrahepatic bile ducts.

Adult↗
PubMed1998

Expression of fibroblast growth factor-1 and fibroblast growth factor-2 in normal liver and hepatocellular carcinoma.

This study was performed to examine the immunohistochemical expression of fibroblast growth factor-1 and fibroblast growth factor-2 in normal liver and a total of 31 cases of hepatocellular carcinoma (HCC). Reactivity for both types of angiogenic factor did not exist in any cellular component of normal liver. For HCC, variable amounts of fibroblast growth factor-1 were detected in 6 of 31 cases (19.4%). There was no apparent relationship between the expression pattern and clinicopathologic factors (P > 0.1, respectively), except a positive correlation with histologic grading (P = 0.04). No tumor showed reactivity for fibroblast growth factor-2 in their cancer cells. However, both types of peptide could be demonstrated in the pericellular stroma of HCC. With a mean follow-up at 60 months, fibroblast growth factor-1 expression did not correlate with patients' outcome (P > 0.1). Our study suggested that fibroblast growth factor-1 appears to play a certain role in hepatocarcinogenesis.

Adolescent↗
PubMed1998

Computer morphometry for quantitative measurement of liver fibrosis: comparison with Knodell's score, colorimetry and conventional description reports.

Liver fibrosis is currently described quite subjectively or, at best, semiquantitatively by scoring systems. In order to measure the severity of liver fibrosis quantitatively and to compare this with established methods, such as Knodell's scoring system, the colorimetric method and conventional description reports, we undertook the present study. A personal computer with an image grabber card and a microscope equipped with a computer-controlled slide-driver was used for computer morphometry. The principle behind morphometry is based on the different colours of hepatocytes and fibres following staining with Masson's trichrome stain. There were 31 patients (25 male, six female) recruited into the present study with a mean +/- SD age of 41.6 +/- 15 years (range 24-66 years). Of these patients, 16 had chronic hepatitis B, 12 had chronic hepatitis C and three were alcoholics. Colorimetric methods and Knodell's fibrosis score were performed according to established protocols. Conventional description reports were obtained from reviews of patient charts. The results from computer morphometry were highly correlated with results from the colorimetric method, with a correlation coefficiency gamma = 0.85 (P<0.0001). The results from computer morphometry also correlated with both Knodell's scoring system (gamma = 0.69; P<0.001) and conventional description reports (gamma = 0.46; P<0.01). Results from Knodell's scoring system were significantly correlated with computer morphometry, as follows: score 0, 2.7 +/- 1.4; score 1, 5.7 +/- 1.2; score 2, 7.7 +/- 2.3; score 3, 10.7 +/- 3.2; score 4, 21.8 +/- 14.1. The trend was statistically significant by the Wilcoxon rank sum test. In conclusion, our computerized morphometry system is a reliable tool for the evaluation of the severity of liver fibrosis and can be used as a tool for the objective quantification of liver fibrosis.

Adult↗
PubMed1998

Experimental assessment of the feasibility of integrating an endoscopic imaging system into an existing hospital information system.

The National Cheng Kung University (NCKU) Hospital operates a comprehensive integrated hospital information system. This was designed and installed as an integral component of the building of the hospital, which opened in 1988. The information system provides a service to all staff in the hospital, administrative and clinical, across the whole of the hospital. To make sure that the information is accessible, where and when it is needed, a comprehensive communications network consisting of both hardware and software mechanisms supports the information system. This paper explores the requirements for a computerised image system for endoscopy and assesses two approaches to the implementation of such a system, as a stand-alone system and as a subsystem of the NCKU hospital information system already in place. The latter would satisfy the original design specification of developing a single system to cover all aspects of hospital operation but places additional demands on the endoscopy systems designer to ensure integration. Both operational modes are set out in the paper and their implications assessed.

Computer Systems↗
PubMed1998

One-week proton pump inhibitor-based triple therapy eradicates residual Helicobacter pylori after failed dual therapy.

The purposes of this study were to assess the efficacy of a 1-week proton pump inhibitor (PPI)-based triple therapy after failure of dual therapy in Helicobacter pylori eradication, and to compare the effectiveness of clarithromycin and metronidazole in this regimen. Between January 1996 and March 1997, 67 patients with persistent H. pylori infection after a 2-week course of dual therapy (amoxicillin plus omeprazole) were enrolled. They were randomly assigned to receive amoxicillin (1000 mg twice daily) and omeprazole (20 mg twice daily) plus either metronidazole (500 mg twice daily) or clarithromycin (250 mg twice daily). Endoscopy was performed in each patient to assess the status of H. pylori using the rapid urease test (CLOtest) and the histologic findings before dual therapy, after dual therapy, and after triple therapy. H. pylori isolates were tested for antibiotic resistance when triple therapy failed. The 1-week triple therapy was well tolerated in both groups with no adverse effects severe enough to cause withdrawal from the trial. Residual H. pylori was eradicated in 94% (33/35) of patients in the clarithromycin group and 84% (27/32) in the metronidazole group; the difference was not statistically significant. All seven patients in whom triple therapy failed were infected with metronidazole-resistant isolates and two also had clarithromycin-resistant isolates. This 1-week triple therapy is safe and effective in eradicating residual H. pylori after dual therapy failure. Failure of the rescue regimen is related to antimicrobial agent resistance. Because of the high metronidazole resistance rate in Taiwan, clarithromycin appears to be more promising than metronidazole for the control of H. pylori.

Adult↗
PubMed1997

Expression of vascular endothelial growth factor in normal liver and hepatocellular carcinoma: an immunohistochemical study.

Angiogenesis is of vital importance during the development and progression of solid tumors. To examine the role of vascular endothelial growth factor (VEGF) in hepatocarcinogenesis, we evaluated the expression of peptide in normal human liver (n = 6) and in 36 cases of hepatocellular carcinoma (HCC). Immunoreactivity for VEGF was present in the extracellular matrix of the portal tracts in the normal and nontumor part of liver, but not in hepatocytes and bile duct epithelium. For HCC, variable amounts of VEGF were expressed in 13 cases (36.1%) of tumor cells. Using a logistic regression model, expression of VEGF was significantly associated with a higher proliferative index (P = .01) and sonographic portal vein thrombosis (P = .05). However, VEGF expression did not correlate with a biochemical liver profile, alpha-fetoprotein levels, histological grading, gender, or clinical stage of cirrhosis (P > 0.1, respectively). Log-rank test showed that evaluation of VEGF did not provide more prognostic information (P > .5) than that from tumor volume and portal vein thrombosis (P < .01, respectively). In addition, VEGF was always present in the fibrovascular stroma or pericellular matrix of HCC, although no strong relationship was observed with the expression of VEGF in tumor cells (P > .5). Our data suggested that expression of VEGF may characterize a progression toward higher proliferation in hepatocarcinogenesis in vivo. The relevance of VEGF existing in the extracellular matrix of the normal liver and HCC remains to be clarified.

Adolescent↗
PubMed1997

Clinical application of gastric histology to monitor treatment of dual therapy in H. pylori eradication.

This preliminary study attempted to test whether pretreatment gastric histology of H. pylori infection may affect the success of dual therapy and to identify which parameter of gastric histology could be improved after dual therapy. One hundred forty-five dyspeptic patients with H. pylori infection received a two-week course of dual therapy (Amoxicillin 500 mg every 6 hr plus omeprazole 20 mg twice a day). In each patient, three pairs of gastric biopsies, sampled from the antrum, lower body, and upper body near the cardia, were collected before treatment and four weeks after completion of dual therapy. The density of H. pylori (score 1-5) and parameters of the modified Sydney system were applied to test the severity of H. pylori-related gastric histology in each specimen. The total bacterial load (score 1-15) was a sum of the density of H. pylori sampled from three biopsies. The overall rate of H. pylori eradication rate by dual therapy is 73.1% (106/145). Univariate analysis of parameters in pretreatment histology disclosed that the presence of mucosal atrophy (P < 0.01), lymphoid follicles (P < 0.005), and higher-density H. pylori (P < 0.001) predisposed to dual therapy failure. Multivariate analysis by stepwise logistic regression further confirmed that both the density of bacteria and the presence of lymphoid follicles are the two major factors related to the outcome of dual therapy (P < 0.001). Four weeks after dual therapy was completed, only patients with successful eradication significantly improved in these gastric histology parameters: acute activity, chronic inflammation, eosinophil infiltration, and mucosal atrophy. However, the lymphoid follicle and intestinal metaplasia were not significantly improved during the study period. The eradication rates among three subgroups with different total bacterial loads (group I: 1-5; II: 6-10; III: 11-15) disclosed a downward trend (I: 89.1%; II: 73%; III: 52.7%). It is concluded that dual therapy could improve gastric histology especially among patients with successful eradication of H. pylori. Evaluating pretreatment histologic parameters, including the density of H. pylori and the presence of lymphoid follicles, is valuable in predicting the success of dual therapy.

Amoxicillin↗
PubMed1997

Implications of Helicobacter pylori serological titer for the histological severity of antral gastritis.

BACKGROUND AND STUDY AIMS: We attempted to determine whether the serological titer of anti-Helicobacter pylori (HP) immunoglobulin (IgG) would be capable of predicting the presence of ulcer, or would correlate with the histological grading of gastritis in patients with dyspepsia. PATIENTS AND METHODS: One hundred eighty-three dyspeptic patients were prospectively included in the study after panendoscopy. Each patient underwent blood sampling for anti-HP IgG titer, and antral biopsy for both a rapid urease test (CLO) and histology. The severity of antral gastritis was semi-quantitated for acute and chronic inflammation scores (range 0-3). RESULTS: The HP findings were positive in 157 patients (85.5%), and their histological inflammation scores and serological titer were higher than those of HP-negative patients (P < 0.05). Based on the endoscopic findings, these 157 patients were classified into ulcer (n = 109) and non-ulcer dyspepsia (n = 48) subgroups. The mean chronic inflammation score in the ulcer subgroup was higher than that in the non-ulcer dyspepsia subgroup (1.77 vs. 1.28, P < 0.001). However, on the basis of only the titer itself, there was no cut-off value for serological titer to predict the presence or absence of ulcer in HP-infected patients. As the scores for either acute or chronic inflammation increased, the mean serological titer rose (acute inflammation score 0-3: 0.63, 0.78, 0.93, 1.39; chronic inflammation score 0-3: 0.18, 0.56, 0.88, 0.91). CONCLUSIONS: The titer of HP serology does not provide a method for predicting the presence of ulcer in patients with HP infection, but may indirectly offer evidence of the severity of histological changes.

Adult↗
PubMed1997

Clinical assessment of the bacterial load of Helicobacter pylori on gastric mucosa by a new multi-scaled rapid urease test.

The present study tests the efficacy of the multi-scaled urease test (MUT) in detecting Helicobacter pylori infection and determines whether the MUT can predict the bacterial density on histology. A total of 111 sets of gastric specimens were obtained from patients with dyspepsia but without recent bleeding. Two biopsies were taken as closely as possible in each set. One sample was used for the MUT (Hp fast; GI Supply, Camp Hill, PA, USA), while the other was used to determine the histological density of H. pylori by modified Giemsa stain (grade 0-5). The results of MUT were interpreted as negative if the colour was yellow or bright green (reaction score 0) and positive if the colour was green, light blue, or blue (reaction score 1, 2 and 3, respectively). The reaction scores of MUT were recorded sequentially at 15 and 30 min and 1, 4 and 24 h. On the basis of histological confirmation, MUT had a sensitivity of 89.6%, a specificity of 88.2%, a positive predictive value of 94.5% and a negative predictive value of 78.9%. Focusing on specimens with the presence of bacteria under histology, 77 specimens were divided into five subgroups by grades of density of H. pylori (HPD1-5). The reaction scores had become sequentially elevated from 30 min through to 24 h in each subgroup. For subgroups HPD4 and 5, the positive rates of MUT were 70.6 and 66.6%, respectively, as early as 30 min and progressed to 100% within 4 h. In contrast, the positive rate for the HPD1 subgroup was 16.6% at 4 h and increased to only 62.5% at 24 h. In subgroups HPD 2 and 3, the positive rates were less than 30% at 30 min, but became more than 66.6% at 4 h and were 100% at 24 h. The early (i.e. mean value of reaction scores before 4 h) and late (24 h) mean reaction scores disclosed two elevated trends as the density of H. pylori increased (early: 0.2, 0.7, 0.8, 1.5, 1.2; late: 1.4, 2.3, 2.6, 3.0, 3.0; P < 0.05). In conclusion, MUT is a reliable method for the diagnosis of H. pylori infection. It can also indirectly predict the density of H. pylori on histology.

Biopsy↗
PubMed1996

Bacterial density of Helicobacter pylori predicts the success of triple therapy in bleeding duodenal ulcer.

BACKGROUND: We studied whether different initial bacterial densities of Helicobacter pylori would alter the eradication rate of H. pylori by triple therapy (amoxicillin 500 mg t.i.d. and metronidazole 500 mg t.i.d. for 14 days; bismuth subcitrate 120 mg t.i.d. for 28 days) in patients with duodenal ulcer bleeding. METHOD: One hundred thirty-six cases with duodenal ulcer bleeding and H. pylori infection (proved by rapid urease test and histology during emergency endoscopy) were studied. One hundred twenty-seven of these patients completed a course of triple therapy. In each case, anti-H. pylori IgG titer, gastric biopsies for H. pylori density (score 1 to 5), and evaluation of severity of gastritis were collected at the first endoscopy and 1 month after completion of the triple therapy. RESULTS: The ulcer healing rate was 84.3% (107 of 127) at the time of the second evaluation. The eradication rate of H. pylori was 76.4% (97 or 127). Eradication for H. pylori failed in 30 cases. In these eradication failure cases, initial serologic titer and density of H. pylori were higher than those of eradication success cases. The eradication rate of H. pylori decreased as the initial density of H. pylori increased (density of H. pylori: 1, 88.3%; 2, 83.8%; 3, 74.2%; 4, 68%; 5, 50%). At the second evaluation, the serologic titer was lower and continued to decline in eradication success cases whose mean residual titer ratio (100% x follow-up titer/initial titer) was lower than that of eradication failure cases (57.1% +/- 14.6% vs 107.1% +/- 24.1%, p < 0.001). The mean residual titer ratio also disclosed an upward trend as the density of H. pylori increased (density of H. pylori 1 to 5: 57.5%, 66.6%, 73.5%, 75.3%, 81.8%, respectively). CONCLUSIONS: We suggest routine gastric biopsy to detect both the presence of H. pylori and its density inasmuch as quantitative results may predict the usefulness of triple therapy. The higher the H. pylori density, the less effective triple therapy will be at successful eradication of H. pylori.

Adult↗
PubMed1996

When to discharge patients with bleeding peptic ulcers: a prospective study of residual risk of rebleeding.

BACKGROUND: From January 1993 to December 1994, we conducted a prospective study to investigate the evolutionary change of rebleeding risk in bleeding peptic ulcers. To obviate possible confounding factors that would influence decision making for discharge of patients, subjects with coexistent acute illnesses, systemic bleeding disorders, alcoholism, and use of nonsteroidal anti-inflammatory drugs were excluded. METHODS: Emergency endoscopies were performed in patients with hematemesis or a melena within 24 hours of admission. Ulcer lesions were divided into six categories according to endoscopic findings. The residual risks of rebleeding of each type of ulcers were calculated for 10 days, and the critical point of acceptable rebleeding risk after discharge was set at 3%. RESULTS: Three hundred ninety-two patients with bleeding peptic ulcers completed the study. The ulcers, characterized by clean bases, red or black spots, adherent clots, nonbleeding visible vessels without local therapy, nonbleeding visible vessels with local therapy, and bleeding visible vessels with local therapy took 0, 3, 3, 4, 4, and 3 days, respectively, to decrease rebleeding risk to below the critical point. All episodes of fatal rebleeding (n = 4) occurred within 24 hours after admission. CONCLUSIONS: Patients with clean-based ulcers can be discharged in the first day of admission. The optimal duration required for hospitalization of patients with ulcers characterized by nonbleeding visible vessels at initial endoscopy is 4 days. The remaining patients with ulcers marked by other bleeding stigmata may be discharged after a 3-day observation.

Adolescent↗
PubMed1996

C-reactive protein for the evaluation of acute abdominal pain.

The diagnostic value of C-reactive protein (CRP) was established in 143 patients with acute abdominal pain, 67 men and 76 women with mean age of 48 +/- 20 years old. Clinical and laboratory variables were collected after the patients' arrival at the emergency department. The attending clinicians did not consider the CRP value during the study period and did not use it for their management. When patients were grouped by final disposition, which was according to severity, only CRP and leukocyte count were identified as significant quantitative variables by multivariate analysis. CRP can detect the serious conditions, ie, in 79% of the hospitalized group, although specificity was 64%, the total accuracy was 73%. When elevated CRP was combined with leukocytosis, the diagnostic value was much improved, with specificity of 89% and positive predictive value of 88%. The sensitivity was improved to 90% when elevated CRP or leukocytosis was used. It is thus concluded that CRP is a helpful quantitative variable for disposition decision-making in patients with acute abdominal pain.

Abdomen, Acute↗
PubMed1996

Incidence of post-transfusion hepatitis in Taiwan before and after introduction of anti-HCV testing.

The effectiveness of second-generation anti-hepatitis C virus antibody (anti-HCV) screening of blood donations for the prevention of non-A, non-B post-transfusion hepatitis (NANB PTH) was assessed. A prospective study of 192 transfusion recipients was performed to compare the incidence of NANB PTH after the introduction of the second-generation anti-HCV test with the incidence before its introduction. We used a polymerase chain reaction to detect HCV-RNA and HBV-DNA in the sera of patients with NANB PTH. The incidence of acute post-transfusion hepatitis C was 11% (8 of 71) before the screening for anti-HCV as compared with 2.5% (3 of 121) after the screening (p < 0.05). Viremia was detected within the first five weeks of infection in 10 patients with acute post-transfusion hepatitis C. However, there was no significant difference in the incidence of non-A, non-B, non-C (NANBNC) PTH before screening (3 of 71, 4.2%) compared with after screening (3 of 121, 2.5%). Usually, NANBNC PTH was not clinically important. Anti-HCV screening of blood donors significantly reduces the incidence of post-transfusion hepatitis C, but not the incidence of NANBNC PTH.

Adolescent↗