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Biomedical subjects

F Y Chang

Publications and source records attributed to F Y Chang.

At least 109 records · Page 6Linked to original sources
PubMed2000

Staphylococcus aureus bacteremia and endocarditis.

Staphylococcus aureus bacteremia is a serious and common disease often associated with infective endocarditis. It occurs in both healthy, immunologically competent people in the community and compromised patients in the hospitals. For S. aureus bacteremia, questions on clinical issues such as antimicrobial treatment are raised. Is nafcillin/oxacillin superior to vancomycin? Does the addition of rifampin improve outcome? Does addition of aminoglycoside improve the outcome? Does increasing duration of therapy (> 4 weeks versus < 2 weeks) improve outcome? How many cases of community-acquired S. aureus bacteremia have endocarditis on admission? What are the risk factors that would separate bacteremia from endocarditis? What is the role of echocardiography? What are the indications for routine echocardiography? Are methicillin-resistant S. aureus (MRSA) more virulent than methicillin-susceptible S. aureus (MSSA)? What factors predict mortality in S. aureus bacteremia? Herein, the above important issues on S. aureus bacteremia and endocarditis are critically reviewed.

Animals↗
PubMed2000

Clinical, virologic and pathologic significance of elevated serum gamma-glutamyl transpeptidase in patients with chronic hepatitis C.

BACKGROUND: Elevated serum gamma-glutamyl transpeptidase (GGT) is often seen in patients with chronic hepatitis C virus (HCV) infection and is associated with a poor response to interferon treatment. The pathogenesis of these phenomena is unclear. Therefore, we assessed the prevalence of elevated serum GGT in Chinese patients with chronic hepatitis C and evaluated the clinical, biochemical, virologic and histologic features of this phenomenon. METHODS: One hundred and twelve patients with biopsy-proven chronic hepatitis C were enrolled. Patients who were habitual alcohol drinkers, alcoholics or had diabetes mellitus were excluded. RESULTS: Forty-three (38.4%) of 112 patients had elevated serum GGT (> 60 U/l). Patients with elevated serum GGT had significantly higher serum levels of alanine and aspartate aminotransferases, alkaline phosphatase and total bilirubin, significantly higher histologic scores of liver lobular necro-inflammation and fibrosis when compared to patients with normal serum GGT. Elevated serum GGT was not correlated to serum HCV RNA titer or HCV genotype. Multivariate logistic regression analysis showed that a histologic fibrotic score > or = 2 was the only significantly independent predictor associated with elevated serum GGT. Fifty-seven of 112 patients completed a six-month course of interferon treatment. Patients with elevated serum GGT had a significantly lower sustained response rate to interferon when compared to patients with normal serum GGT (8% vs 30%, p = 0.042). CONCLUSIONS: Elevated serum GGT in chronic hepatitis C patients was frequently associated with more severe hepatic fibrosis or cirrhosis and may, in part, account for poor response to interferon therapy.

Adult↗
PubMed2000

Resolution of refractory hepatic hydrothorax after chemical pleurodesis with minocycline.

Management of refractory hepatic hydrothorax is a challenge to physicians in clinical practice. We reported two patients with hepatic hydrothorax, non-alcoholic cirrhosis and rapidly recurring pleural effusion. They failed to improve with diuretics and repeated thoracentesis. Refractory hepatic hydrothorax was successfully treated by minocycline-induced pleural symphysis. After pleurodesis, ventilatory function returned to normal in both patients. No recurrence of pleural effusion was noted. We suggest that minocycline pleurodesis is an alternative treatment for refractory hepatic hydrothorax because it is simple, safe and effective.

Aged↗
PubMed2000

Splanchnic hyposensitivity to glypressin in a haemorrhage/transfused rat model of portal hypertension: role of nitric oxide and bradykinin.

Hyposensitivity to vasopressin is a well documented phenomenon in animals with portal hypertension and patients with cirrhosis subject to haemorrhage. Haemorrhage is associated with the endogenous release of bradykinin, which may subsequently stimulate the formation of nitric oxide (NO). The present study investigated the relative contribution of NO synthase (NOS) isoforms and the role of bradykinin in the pathogenesis of splanchnic hyposensitivity to a long-acting vasopressin analogue, glypressin, in rats with portal hypertension induced by partial portal vein ligation (PVL). At 14 days after the operation, systemic and portal haemodynamics were measured in stable or bleeding PVL rats receiving an intravenous infusion of glypressin (0.07 mg/kg). In the treatment groups, N(G)-nitro-L-arginine methyl ester (L-NAME; a non-selective NOS inhibitor), L-canavanine (a specific inhibitor of inducible NOS) or HOE 140 (a bradykinin B(2) receptor antagonist) was administered 45 min before the infusion of glypressin. In rats with a hypotensive haemorrhage, 4.5 ml of blood was withdrawn and 50% of the withdrawn blood was re-infused before the administration of glypressin or various inhibitors. Splanchnic hyposensitivity to glypressin was demonstrated in the haemorrhage/transfused PVL rats. The infusion of L-NAME elevated the mean arterial pressure in the bleeding PVL rats without the modulation of portal pressure. The addition of L-NAME or HOE 140, but not L-canavanine, significantly and similarly potentiated the portal-hypotensive effects of glypressin. It is concluded that constitutive NOS and bradykinin are responsible, at least partly, for the splanchnic hyposensitivity to glypressin observed in the early stages of the haemorrhage/transfused rat model of portal hypertension.

Animals↗
PubMed2000

Need for vaccination of susceptible food handlers against hepatitis A in Taiwan.

BACKGROUND: With the improvement in the socioeconomic situation and general hygiene standards in Taiwan, the prevalence of antibodies to the hepatitis A virus (anti-HAV) in the general population has declined markedly in recent years. To avoid food-borne outbreaks of HAV infection caused by susceptible food handlers in Taiwan, we investigated the seroprevalence of anti-HAV among the target population and also evaluated the immunogenicity and reactogenicity of the inactivated hepatitis A vaccine in this study group. METHODS: Two hundred and forty-four food handlers employed in four restaurants at Taipei Veterans General Hospital participated in the anti-HAV serologic screening program in July 1997. Of them, 48 susceptible food handlers received three doses of 720 enzyme-linked immunosorbent units of inactivated hepatitis A vaccine at 0, 1 and 6 months. RESULTS: Of the 244 food handlers who underwent anti-HAV serologic screening, 169 (69.3%) were anti-HAV positive. The seroprevalence of anti-HAV was related to age: 91.5% of food handlers over 30 years of age were positive for anti-HAV but only 22.8% of food handlers younger than 30 were anti-HAV positive. Anti-HAV response was observed in all vaccinees after a booster vaccination at month 6. The response persisted to 1 year. The side-effects of the vaccinations were minimal. CONCLUSIONS: Susceptible food handlers should receive hepatitis A vaccination. Hepatitis A vaccine is safe and immunogenic in this target population.

Adolescent↗
PubMed2000

Abdominal wall necrosis following transcatheter arterial chemoembolization for hepatocellular carcinoma.

A 76-year-old man, who had inoperable hepatocellular carcinoma, had been treated with transcatheter arterial chemoembolization (TACE) 11 times, percutaneous ethanol injection therapy three times and conformal radiotherapy once, all in other hospitals. At this admission, he developed myocutaneous necrosis in the right abdominal wall after TACE, via the collateral of the right internal mammary artery (IMA). Necrosis of the abdominal wall was due to ischemic changes caused by embolization of the distal branches of the IMA, which were aggravated by previous radiation therapy. We advise that embolization of the IMA in patients who have received radiotherapy should be avoided, if possible.

Abdominal Muscles↗
PubMed2000

Outcomes of Aeromonas bacteremia in patients with different types of underlying disease.

Over a 6-year period, 42 patients with different underlying diseases developed Aeromonas bacteremia in our hospital. The male to female ratio was 2:1. The vast majority of these patients had underlying diseases, including various types of neoplasm (n = 14), liver cirrhosis (n = 11), biliary tract disorder (n = 10) and other illnesses (n = 7). Community-acquired bacteremia was predominant (33 cases, 79%). Aeromonas hydrophila was the most common species isolated (88%). Monomicrobial bacteremia was more common than polymicrobial bacteremia (64% vs 36%). Monomicrobial bacteremia was associated with neoplasm or liver cirrhosis in 80% of patients. Polymicrobial bacteremia was more common in patients with biliary tract disorder than in patients from other groups (60% vs 40%). Escherichia coli (60%) was the predominant concomitant organism isolated. The major clinical manifestations were fever (74%), jaundice (57%), and abdominal pain (45%). Recognized infection sites included biliary tract, soft tissue involvement, peritoneal involvement, while 50% of patients had no recognized infection site. Eight patients (80%) received cholecystectomy due to gall stone with acute cholecystitis. However, none of the cirrhotic patients with necrotizing fasciitis received surgical treatment. The mortality attributed to Aeromonas bacteremia was 70%. Patients with liver cirrhosis or malignancy had a higher acute mortality (death within 7 days after admission) than the other patients (89% vs 11%). We conclude that Aeromonas bacteremia can cause a rapidly fatal outcome and should be considered an important pathogen for septicemia in patients with liver cirrhosis or neoplasm.

Adult↗
PubMed1999

Calcium rather than calcitonin is dominant to mediate gastric emptying in thyroidectomized rats.

Both calcium and calcitonin are important in mediating gastrointestinal motility. Present study tried to study what was the dominant role of calcitonin or calcium replacement on the gastric emptying in thyroidectomized animals. Adult Sprague-Dawley male rats received thyroidectomy or sham operation and then housed for two weeks until motility study, which was conducted using radiochromium to measure gastric emptying. Before motility study these rats were i.p. injected with saline or human calcitonin in the doses of 0.1, 1 and 10 microgM/kg, respectively. Another group of thyroidectomized rats received i.v. infusion of saline or CaCl2 for 30 min before motility study. Among thyroidectomized rats, neither saline nor various doses of calcitonin treatment disturbed gastric emptying compared to this of sham operated rats. Thyroidectomy diminished plasma calcium level, however, additional calcitonin treatment did not restore the suppressed calcium level (P<0.01). Of rats following saline or CaCl2 infusion, thyroidectomy did not change gastric emptying, whereas CaCl2 infusion enhanced gastric emptying (P<0.05). In conclusion, exogenous calcium treatment further enhances gastric emptying in thyroidectomized rats, whereas calcitonin replacement has no effect on gastric emptying. We suggest that calcium rather than calcitonin is dominant to mediate gastric emptying.

Animals↗
PubMed1999

Paraneoplastic syndromes in patients with hepatocellular carcinoma in Taiwan.

BACKGROUND: Hepatocellular carcinoma (HCC) is the most common malignancy in Taiwan. Some patients may manifest paraneoplastic syndromes during the clinical course of the disease. In this study, the authors evaluated the clinical significance of these paraneoplastic syndromes, compared the prevalence of these syndromes between cases of hepatitis B virus (HBV)-related and hepatitis C virus (HCV)-related HCC, and estimated significant predictors associated with the syndromes. METHODS: Clinical data on 1197 HCC patients, including age, gender, Child-Pugh score, survival time, laboratory data (including liver biochemistry, hepatitis markers, and serum alpha-fetoprotein [AFP]), and tumor features (including tumor size, portal vein thrombosis, and histologic pictures), were retrospectively reviewed. RESULTS: A total of 232 of 1197 patients (19.4%) had paraneoplastic syndromes. HCC patients with paraneoplastic syndromes had significantly higher serum AFP; higher rates of initial main portal vein thrombosis, metastasis, and bilobal tumor involvement; larger tumor volume; and shorter survival than those without these syndromes. Patients with HBV-related HCC had a significantly higher prevalence of paraneoplastic syndromes than patients with HCV-related HCC (20.1% vs. 11.2%, P = 0.005). In a stepwise multivariate logistic regression analysis, AFP >50,000 ng/mL and tumor volume >30% were significant predictive variables associated with the presence of paraneoplastic syndromes in HCC patients. CONCLUSIONS: HCC patients with paraneoplastic syndromes usually had higher levels of serum AFP and larger tumor volumes than those without. Patients with HBV-related HCC had a significantly higher prevalence of paraneoplastic syndromes than those with HCV-related HCC.

Aged↗
PubMed1999

Variation of capsaicin-sensitive motor activities along the rat gastrointestinal tract.

Variation in motility may be a character to move gut contents. The aim of present study was to assess whether the rat upper gastrointéstinal motilities were variable according to the segments or studied periods under systemic capsaicin treatment. Sedated rats were intubated with a catheter to feed a suspension containing both charcoal and radiochromium motility markers. Capsaicin in the doses of 0.5 mg kg-1, 1 mg kg-1, 5 mg kg-1 or vehicle were simultaneously injected via intraperitoneal route. They were sacrificed at 5 min or 30 min later and the whole gut was removed. Charcoal transit in the small intestine was computed while the radioactivities of stomach and ten equally divided small intestinal segments were counted to obtain the gastric emptying and geometric center of intestinal transit, respectively. Large dose treatment inhibited early gastric emptying (p < 0.05), whereas late gastric emptying remained unchanged. Larger dose treatment inhibited charcoal represented transit in the early (p < 0.05) and late periods (p < 0.01). The intestinal transits seen with geometric center were almost similar to these of charcoal representation (p < 0.01). In conclusion, capsaicin-sensitive gastric emptying changes with studied periods while intestinal transit is always inhibited at any period. We confirm the notion of variation in capsaicin-sensitive motor responses along the rat upper digestive organ.

Animals↗
PubMed1999

Long-term follow-up of hepatitis A vaccination in children.

We conducted this follow-up study to evaluate the long-term immunogenicity of an inactivated hepatitis A vaccine in children. Ninety-six children who had seroconversion to antibody to HAV (anti-HAV) after receiving a three-dose schedule of inactivated hepatitis A vaccine were enrolled into this study. Sixty months after the initial vaccination, all vaccinees who received annual follow-up still had protective levels of anti-HAV. The geometric mean titer (GMT) of anti-HAV, peaking at month 7 (4133 mIU/mL), kept declining throughout the follow-up period. The GMTs in months 12, 24, 36, 48 and 60 were 1722, 896, 896, 645 and 403 mIU/mL, respectively. Nine of the vaccinees were hepatitis B virus carriers. Their anti-HAV titers tended to be lower than those of the remaining vaccinees at all time-points, but the difference was not significant (p > 0.05). Natural booster was noted in one vaccinee during the follow-up period. In conclusion, inactivated hepatitis A vaccine is safe and immunogenic in children, the duration of protection against HAV infection is longer than five years.

Child↗
PubMed1999

Comparison of the nucleic acid-based crosslinking hybridization assay and the branched DNA signal amplification assay in the quantitative measurement of serum hepatitis B virus DNA.

Quantitative measurement of hepatitis B virus (HBV) DNA has become important in the clinical diagnosis of patients with chronic hepatitis B, especially in patients with hepatitis B e antigen (HBeAg)-negative precore mutant and in patients who received treatment with interferon or antiviral agents. Two different hybridization assays for quantitative measurement of HBV DNA: Naxcor crosslinking assays and Chiron branched DNA signal amplification (bDNA) assay, were applied to 158 serum samples which were positive for HBV DNA by polymerase chain reaction. Among 158 serum samples, 135 samples (85.4%) were positive by the crosslinking assay and 129 samples (81.6%) were positive by the bDNA assay in the quantification of serum HBV DNA (P > 0.05). Serum HBV DNA levels obtained from both assays showed a good linear correlation (r = 0.91, P < 0.001). The sensitivity of both assays in HBeAg-positive samples was 90.5%, significantly higher than in HBeAg-negative samples (69.6% for the crosslinking assay and 56.5% for the bDNA assay, P < 0.05). In HBeAg-negative patients with elevated serum alanine transaminase levels, the so-called precore HBV mutant, the detection sensitivity for HBV DNA was better in the crosslinking assay (83%) than in the bDNA assay (61%). The crosslinking assay was less time consuming than the bDNA assay in performing the measurement of serum HBV DNA (6 hours vs. 20 hours). In conclusion, Naxcor crosslinking hybridization assay was equally as sensitive as Chiron bDNA assay in the quantitative measurement of serum HBV DNA. Less time-consuming procedures and better sensitivity in the detection of HBeAg-negative samples with elevated serum alanine transaminase levels may favor the clinical use of the crosslinking assay.

Adult↗
PubMed1999

Effects of vasopressin on portal-systemic collaterals in portal hypertensive rats: role of nitric oxide and prostaglandin.

This study investigated the effect of vasopressin on portal-systemic collaterals in portal hypertensive rats and the influence of nitric oxide (NO) and prostaglandin on the responsiveness of collateral vessels to vasopressin. The vascular responsiveness to graded concentrations of vasopressin was tested with or without the incubation of n(omega)-nitro-L-arginine (NNA) (100 micromol/L) and/or indomethacin (10 micromol/L) in perfused collateral vascular beds of rats with portal hypertension induced by partial portal vein ligation. In addition, concentration-response curves to vasopressin with incubation of a vasopressin V(1) receptor antagonist d(CH(2))(5)Tyr(Me) arginine vasopressin and concentration-response curves to a V(2) receptor agonist 1-desamino-8-D-arginine vasopressin were performed. Vasopressin significantly increased the perfusion pressure of collaterals, and this effect was suppressed by the addition of the V(1) receptor antagonist. Perfusion with the V(2) receptor agonist had no effect on the collaterals. Incubation with NNA, indomethacin, or both significantly potentiated the response of collaterals to vasopressin. In addition, the pressor response to vasopressin in the combination group was significantly higher than that in the NNA-alone group. The results show that vasopressin produces a direct vasoconstrictive effect on the portal-systemic collaterals of portal hypertensive rats. This effect is mediated by the vasopressin V(1,) but not V(2), receptors. The attenuation of the response to vasopressin by NO and prostaglandin suggest a function role of both mediators in the regulation of the portal-systemic collateral circulation in portal hypertensive rats.

Animals↗
PubMed1999

Helicobacter pylori clearance and serum gastrin and pepsinogen I concentrations in omeprazole treatment of duodenal ulcer patients.

OBJECTIVE: To determine which demographic factors may influence serum gastrin and pepsinogen I (PGI) levels in duodenal ulcer patients undergoing omeprazole treatment. METHODS: We conducted an outpatient-based prospective study in the Veterans General Hospital, Taipei, to investigate the pharmacological effects on patients with duodenal ulcers receiving omeprazole treatment for 4 weeks. Sixty-eight patients (61 males/7 females, aged 25 73 years) with endoscopically confirmed duodenal ulcer were included. Gastrin and pepsinogen I levels were measured before and after treatment. Demographic factors including age, sex, smoking, ulcer healing and antral Helicobacter pylori colonization/clearance were analyzed, in order to measure their probable influences on serum gastrin and pepsinogen I levels. RESULTS: Ulcer healing was seen in 92.6% of patients while 48 (70.6%) antral clearances were seen in 66 H. pylori colonized patients at the end of trial. Omeprazole monotherapy led to a marked elevation of serum gastrin (85.8 pg x ml(-1), SD 32.0 pg x ml(-1) vs 133.9 pg x ml(-1), SD 71.6 pg x ml(-1), P < 0.01), and pepsinogen I (111.0 ng x ml(-1), SD 36.7 ng x ml(-1) vs 253.6 ng x ml(-1) , SD 64.8 ng x ml(-1), P < 0.01) levels when measured on day 29. Only patients showing antral H. pylori clearance exhibited an influence on the magnitude of pepsinogen I elevation following omeprazole monotherapy (143.9%, SD 67.3% vs 78.6%, SD 51.2%, P < 0.01). Moreover, the sensitivity and specificity of serum pepsinogen I variations were plotted on a receiving operating characteristic (ROC) curve. The 140% increased pepsinogen I level yielded a maximum accuracy of 80% specificity or 50% sensitivity to predict antral H. pylori clearance. CONCLUSION: Antral H. pylori clearance is at least partially responsible for the omeprzaole-induced hyperpepsinogenemia I. The magnitude of hyperpepsinogenemia I probably provides a non-invasive alternative for predicting H. pylori clearance.

Adult↗
PubMed1999

Effects of sustained-release lanreotide on hemodynamics in rats with portal vein stenosis.

BACKGROUND/AIMS: Somatostatin and its analogue have been shown to provide beneficial effects in the management of portal hypertension and hyperdynamic circulation. The current study was undertaken to evaluate the effects of lanreotide, a sustained-release somatostatin analogue, on hemodynamics in rats with portal hypertension. METHODS: Immediately after portal vein stenosis, rats were randomly assigned to receive vehicle or a single intramuscular injection of lanreotide 10 mg/kg. Hemodynamic measurements (radioactive microsphere technique) with portal systemic shunts determinations were performed on the 4th and 8th day after surgery, respectively. RESULTS: On the 4th day after surgery, rats treated with lanreotide had significantly lower cardiac index and higher systemic vascular resistance than rats treated with vehicle, while these values were no different on the 8th day after portal vein stenosis. In contrast, the elevation of portal pressure, portal tributary blood flow, and splanchnic fraction of cardiac output had ameliorated following lanreotide administration associated with an increase in splanchnic arterial resistance. Portal systemic shunts were lower in rats receiving lanreotide than in rats receiving vehicle. CONCLUSION: The current study showed that a single injection of sustained-release lanreotide in rats with portal vein stenosis delayed the development of peripheral arterial vasodilatation and hyperdynamic circulation, while it modified the evolution of portal hypertension and splanchnic hyperemia. This treatment also prevents, in part, the development of portal systemic shunts in rats with portal vein stenosis.

Animals↗
PubMed1999

Evidence against a role for endotoxin in the hyperdynamic circulation of rats with prehepatic portal hypertension.

BACKGROUND/AIMS: Excessive formation of nitric oxide may mediate the generalized vasorelaxation and hyporesponsiveness to vasoconstrictors observed in portal hypertensive states. Endotoxin, released from the bowel and detoxified by the liver, could stimulate inducible nitric oxide synthase directly or indirectly via the cytokine cascade. This study investigated the effect of chronic intraperitoneal injection of polymyxin B, a neutralizing antagonist of endotoxin, on the hemodynamics of partially portal vein-ligated (PVL) rats. METHODS: Concomitantly with endotoxin (600 EU) and dactinomycin (80 microg), polymyxin B (0.1 mg) or normal saline (N/S) was administered via an intraperitoneal route to male Sprague-Dawley rats. Twenty-four hours later, mean arterial pressure was determined. In PVL rats polymyxin B (0.1 mg in 5 cc N/S) or N/S was given intraperitoneally twice daily from 2 days prior to operation until 5 days (short-term) or 14 days (long-term) after the operation. Long-term polymyxin B- or N/S-treated sham-operated rats were included as controls. Hemodynamic studies with a thermodilution technique were performed at the end of treatment. Blood samples were collected from another series of PVL rats with long-term treatment to determine plasma levels of endotoxin and tumor necrosis factor-alpha. Plasma levels of endotoxin and tumor necrosis factor-alpha were measured by Limulus assay and the ELISA method, respectively. RESULTS: With the dosage of 0.1 mg polymyxin B, hypotension in rats subjected to endotoxin and dactinomycin administration could be corrected (polymyxin B vs. placebo: 130.0+/-7.7 vs. 108.8+/-6.7 mm Hg, p<0.05). However, long-term or short-term treatment with the same dosage of polymyxin B failed to ameliorate the hyperdynamic circulation of PVL rats. In addition, long-term treatment with polymyxin B did not change systemic and portal hemodynamics in sham-operated rats. Plasma levels of endotoxin and tumor necrosis factor-alpha were comparable in PVL rats treated with long-term polymyxin B or N/S (p>0.05). CONCLUSIONS: Our findings do not support the role of endotoxin in the hyperdynamic circulation of PVL rats.

Animals↗
PubMed1999

Smoking and male gender rather than CagA protein are associated with increased risk for duodenal ulcer in Helicobacter pylori-infected patients in Taiwan.

The aim of this study was to examine the seroprevalence of antibody to CagA antigen, as well as other major H. pylori antigens by Western blot in H. pylori-infected subjects with endoscopically normal mucosa (N = 54) and duodenal ulcer (N = 51). The role of the host and environmental factors was also evaluated. There was no significant difference in the prevalence of antibodies against the major H. pylori antigens between the two groups. A high prevalence of antibody to CagA was detected in patients with normal mucosa (93%) and duodenal ulcer (86%). Multivariate analysis shows that male gender (odds ratio = 4.94, 95% CI = 1.39-17.77, P = 0.014) and smoking (odds ratio = 8.89, 95% CI = 2.17-36.48, P = 0.002) were associated with duodenal ulcer disease. This study suggests that smoking and male gender rather than CagA protein are associated with increased risk for duodenal ulcer in H. pylori-infected patients in Taiwan.

Antibodies, Bacterial↗