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Biomedical subjects

C L Lai

Publications and source records attributed to C L Lai.

At least 55 records · Page 3Linked to original sources
PubMed2000

Hypothyroid myopathy-pathological and ultrastructural study.

Seventeen patients with hypothyroid myopathy were studied before and after thyroxine (T4) treatment. The severity of clinical myopathy was assessed with the aid of a modified rating scale. Laboratory findings including thyroid function, serum creatine kinase (CK), and electromyography were assessed at regular time intervals until a final muscle biopsy was performed. The average period of follow-up was 1.8 years. The authors emphasize: 1) in skeletal muscle pathology of hypothyroidism, the fiber atrophy and increased central nuclear counts are evidence of clinical myopathy during thyroxine treatment; 2) in ultrastructural pathology, the abnormal glycogen accumulation accounts largely for clinical severity and its ongoing resolution is parallel to steady amelioration following T4 therapy, while mitochondrial abnormalities are insignificant in clinical correlation and probably become permanent in some cases with prolonged hypothyroidism; and 3) serial needle biopsies of skeletal muscle are impractical for long-term study of hypothyroid myopathy, but they may be reserved for those patients with a sustained myopathic complaints on T4 therapy.

Adult↗
PubMed2000

No sex and age influence on the expression pattern and activities of human gastric alcohol and aldehyde dehydrogenases.

BACKGROUND: Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) are the principal enzymes responsible for ethanol metabolism in humans. The stomach is involved in the metabolism of alcohol during absorption. Conflicting reports exist with regard to the influence of sex and age on the activity of ADH in the human gastric mucosa. The purpose of the present study was to determine the effects of age and sex on the expression pattern and activities of stomach ADH and ALDH. METHODS: A total of 115 endoscopic gastric biopsy specimens were investigated from Han Chinese men (n = 70) and women (n = 45) aged 20-79 years with approximately even distribution among 10-year age intervals. The expression patterns of ADH and ALDH were identified by isoelectric focusing, and the activities were assayed spectrophotometrically. RESULTS: The expression patterns of gastric ADH and ALDH remained unchanged with respect to sex and age. At 33 mM or 500 mM ethanol, pH 7.5, the ADH activities did not differ significantly among the various age groups or between men and women. At 200 microM or 20 mM acetaldehyde, the ALDH activities did not differ significantly in relation to sex and age. No correlations were found between the ADH or ALDH activities at both the high and low substrate concentrations and the ages in men and women. CONCLUSIONS: The results indicate that there is no significant effect of either sex or age on the expression pattern and activity of ADH and ALDH in the human gastric mucosa. The stomach ADH seems unlikely to account for possible variations in the first-pass metabolism of alcohol with regard to sex and age.

Adult↗
PubMed2000

Evaluation of a new referral system for the management of dyspepsia in Hong Kong: role of open-access upper endoscopy.

BACKGROUND: In the management of dyspepsia, upper endoscopy is an important component. In our locality, patients requiring upper endoscopy are conventionally referred to specialist clinics by family physicians. We have introduced the first open-access upper endoscopy service in Hong Kong, which has allowed family physicians to arrange endoscopy without prior specialist consultation. A study on the outcome of open-access upper endoscopy in contrast with the conventional referral system was conducted. METHODS: For patients presenting with dyspepsia, family physicians in our region were given the option to arrange upper endoscopy directly with our Medical Endoscopy Unit in addition to the conventional referral to specialist clinics. The results were compared with those from the specialist clinic. A detailed prospective follow up was performed from June to September 1997 to evaluate the outcome and impact of open-access upper endoscopy. RESULTS: From November 1996 to September 1999, 978 referrals for open-access upper endoscopy were received. The service significantly reduced the waiting time for the procedure by 16 weeks. Open-access upper endoscopy had similar detection rates for peptic ulcers and cancers compared with referrals from specialist clinics. Seventy-five percent of patients did not require further consultation with their family physicians within 2 months after endoscopy. It is a safe and effective procedure in establishing a definitive diagnosis. All family physicians were satisfied with the open-access upper endoscopy service. CONCLUSIONS: This is the first Asian report on this service. Open-access upper endoscopy reduced waiting time from the patient perspective, decreased subsequent consultations with family physicians and reduced referral to specialist clinics as well as increased patient and doctor satisfaction. Both referral systems for endoscopy were similar in terms of the diagnostic yield.

Ambulatory Care Facilities↗
PubMed1999

Applicability of living donor liver transplantation to high-urgency patients.

BACKGROUND: Cadaveric liver donors are scarce in Hong Kong, and the application of liver transplantation to high-urgency patients is limited. We evaluated the use of grafts from living donors in this setting. METHODS: From July 1994 to January 1998, 49 consecutive adult patients who were intensive care unit-bound because of acute or chronic liver failure were put on a high-urgency list for liver transplantation. Family members were not solicited for living donation, and the initiation and decision for living donor liver transplantation (LDLT) was based on the donor's voluntary intent. Assessment of the living donor, including blood tests, computed tomographic volumetry, and angiography, was performed only after informed consent was executed. RESULTS: In 25 of 49 (51%) patients, no family member volunteered as living donor; 23 died awaiting donor organs, and 2 received a cadaveric graft. Twenty-four (49%) patients had 36 family members who volunteered as living donors. Before evaluation of living donor was completed, two patients received a cadaveric liver transplant. LDLT was not performed in nine patients because of recipient contraindications (n=4), ABO blood group incompatibility (n=3), and withdrawal of donor (n=2). Eight of these nine patients died, and one received a cadaveric liver graft. The remaining 13 (27%) patients received grafts from living donors. Four of 5 (80%) patients who underwent cadaveric liver transplantation and 11 of 13 (85%) who underwent LDLT survived. Thus, emergency transplantation from living donors increased the applicability of liver transplantation from 10% to 37%, and the survival rate after emergency LDLT (85%) was superior to that of the remaining patients (11%). CONCLUSIONS: When cadaveric organ donation is scarce, emergency liver transplantation from living donors can be applied to high-urgency adult patients.

Adolescent↗
PubMed1999

Twelve-year follow-up of a prospective randomized trial of hepatitis B recombinant DNA yeast vaccine versus plasma-derived vaccine without booster doses in children.

A total of 318 children were prospectively randomized in group 1 with two 5-microg doses of recombinant vaccine given at 0 and 1 month; in group 2 with three 5-microg doses of recombinant vaccine given at 0, 1, and 6 months; or in group 3 with three doses of plasma-derived vaccine given at 0, 1, and 6 months. Eleven subjects with a hepatitis B surface antigen antibody (anti-HBs) titer of less than 10 mIU/mL at 12 months were given an extra dose of vaccine and were excluded from analysis. No booster doses were given to any other subjects. All children were followed up yearly for the level of anti-HBs titers and for the detection of hepatitis B infection. At the 12th year of follow-up, there were significantly fewer subjects with anti-HBs of 10 mIU/mL or above in group 1 (60.4%) when compared with group 2 (81.4%; P =.0287) and group 3 (79.0%; P =. 0381). The geometric mean titers (GMTs) of subjects of group 1 were significantly lower than those of group 2 and group 3 throughout the 12 years of follow-up. A total of 65 subjects had one or more episodes of anamnestic response. No subject became positive for hepatitis B surface antigen (HBsAg); 2 became positive for hepatitis B core antigen antibody (anti-HBc). In conclusion, the long-term protective immunity was better with three doses of hepatitis B vaccine (either the recombinant or plasma-derived) than with two doses. However, protection from hepatitis B infection could be equally achieved by either two doses or three doses of the vaccine. Booster doses were not necessary, probably because of effective anamnestic response.

Child↗
PubMed1999

Mannose binding lectin gene mutations are associated with progression of liver disease in chronic hepatitis B infection.

Mannose-binding lectin (MBL) plays an important role in immune defense. We examined the MBL gene mutations and MBL levels in Chinese hepatitis B and hepatitis C patients with and without symptomatic cirrhosis. We recruited 190 hepatitis B and C patients, and 117 normal Chinese as controls. Serum MBL levels were measured by enzyme-linked immunosorbent assay. MBL gene mutation at codons 52, 54, and 57 was detected by polymerase chain reaction (PCR) assay. In asymptomatic hepatitis B and C patients, there was no increase in codons 52, 54, and 57 mutation, but the MBL levels were significantly lower than those in the controls. Codon 54 mutation rate was increased to 44.4% (P =.007) in symptomatic hepatitis B cirrhosis and 64.3% (P =.0026) in patients with spontaneous bacterial peritonitis (SBP). There was no increase in codon 54 mutation rate in hepatitis B-related hepatocellular carcinoma (HCC). In chronic hepatitis B infection, the odds ratio for an individual with codon 54 mutation to develop cirrhosis was 1.84 (95% CI: 1.21-2. 81) and to develop SBP was 4.58 (95% CI: 1.73-12.16). Chronic hepatitis B and hepatitis C infection lowered the MBL levels, probably by suppressing MBL production. Codon 54 mutation of MBL was associated with progression of disease in chronic hepatitis B infection.

Adolescent↗
PubMed1999

Triple therapy for Helicobacter pylori eradication is more effective than long-term maintenance antisecretory treatment in the prevention of recurrence of duodenal ulcer: a prospective long-term follow-up study.

BACKGROUND: The effectiveness of Helicobacter pylori eradication treatment and long term acid suppression maintenance in the natural course of duodenal ulcer has not been directly compared. AIM: To compare in a prospective randomized study the effectiveness of H. pylori eradication on the prevention of recurrence of duodenal ulcer with long-term maintenance acid suppression therapy. METHODS: One hundred and fourteen duodenal ulcer patients were randomized to the treatment over a 12-month period. Fifty-seven of them received triple therapy consisting of 1 g sucralfate q.d.s. for 28 days, 300 mg metronidazole q.d.s. for 14 days and 250 mg clarithromycin q.d.s. for 14 days. Another 57 received 20 mg omeprazole q.d.s. for 12 months. An upper endoscopy was performed before treatment, at 6 weeks, and 2, 6 and 12 months after the first endoscopy. Side-effects were self-recorded and clinical follow-ups were arranged for up to 4.25 years. RESULTS: The ulcer healing rate was 90.2% (95% confidence interval (95% CI): 79-97%) in the omeprazole group at 6 weeks as compared to 83.3% (95% CI: 70-93%) in the triple therapy group (P = 0.38). There was a higher success rate of pain control in the omeprazole group. Side-effects were more frequently reported and compliance was poorer in the triple therapy group during the first 4 weeks. During follow-up, more relapses were seen in the omeprazole group (9.8%, 95% CI: 3-21%) than the triple therapy group (4.2%, 95% CI: 1-13%) at 1 year (P = 0.44). All relapses were due to the persistence of H. pylori infection. At the 1 year follow-up, none of the patients who were H. pylori negative had an endoscopic relapse compared to 7 out of 56 patients who remained H. pylori positive (12.5%, 95% CI: 5-24%, P = 0.018). After a mean follow-up of 4.07 years, none of those who remained H. pylori negative had an ulcer relapse while the 11 out of 41 who remained H. pylori positive had an ulcer relapse (26.8%, 95% CI 14-43, P = 0. 0005). CONCLUSIONS: Both regimens were highly effective in healing ulcers. The eradication of H. pylori infection was associated with more side-effects and poor compliance but was more effective than the maintenance therapy in reducing the recurrence of duodenal ulcers. For the prevention of ulcer recurrence, testing of H. pylori status after triple therapy is more important than maintenance therapy.

Adult↗
PubMed1999

Antiviral therapy for hepatitis B and C in Asians.

The clinical features and treatment of chronic hepatitis C in Chinese patients are the same as in Caucasian patients except that 27% of Chinese chronic hepatitis C patients have hepatitis C virus (HCV) genotype 6a. In contrast, Chinese patients with chronic hepatitis B (CHB) differ from Caucasian patients because the Chinese patients are immunologically tolerant to hepatitis B virus (HBV), having acquired hepatitis B infection perinatally or in early childhood. In the treatment of CHB, the short-term aims of loss of hepatitis B virus early antigen (HBeAg) and HBV-DNA need to be reassessed. In 1296 Chinese CHB patients, 67.7% of those who developed complications of cirrhosis or hepatocellular carcinoma, were HBeAg-antibody positive. Longer follow up of patients is, therefore, required to assess the time efficacy of a treatment regimen. After long-term follow up (median 90 months) of 206 Chinese CHB patients treated with interferon alpha (IFN alpha) compared with 203 untreated subjects, IFN alpha conferred no benefit in cumulative HBeAg seroconversion or in HBV-DNA negativity as determined by polymerase chain reaction assays or in decreasing long-term complications of cirrhosis and hepatocellular carcinoma. Lamivudine is a novel nucleoside analogue. In a recent 1 year study in 358 Chinese CHB patients, lamivudine treatment was associated with substantial histological improvement (including a reduction in fibrosis), with HBV-DNA suppression and normalization of alanine aminotransferase levels. However, lamivudine may have to be given on a long-term basis, as withdrawal of lamivudine results in rebound of HBV-DNA to pretreatment levels. The long-term effects of lamivudine are currently being assessed.

Asian People↗
PubMed1999

Lymphocyte subsets in renal allograft recipients with chronic hepatitis C virus infection.

BACKGROUND: The pathogenetic mechanisms of chronic hepatitis C virus (HCV) infection in renal allograft recipients are not well established. This study aimed to examine the relationship between altered immune status and HCV-related liver disease, by determining the changes in peripheral blood lymphocyte and natural killer (NK) cell subsets in these subjects. METHODS: Peripheral blood lymphocyte, NK cell and activation markers were detected by flow cytometry in renal allograft recipients with (TpC+) or without (TpC-) HCV infection, and compared with age- and sex-matched patients with post-transfusional chronic HCV infection (TfC+) and healthy controls. RESULTS: CD19+ cells were reduced in renal allograft recipients compared with controls. TpC+ subjects had increased CD3+CD8+ cells compared with controls, and increased CD3+DR+ cells but reduced CD4+ CD38+ and CD3-CD16/56+ cells compared with controls as well as TfC+ patients. TfC+ patients and controls had similar numbers and proportions for the lymphocyte subsets and NK cells. Chronic liver disease in HCV-infected renal allograft recipients was associated with increased CD3+CD16/56+ cells but reduced CD4+CD38+ cells. Reduction of CD3-CD16/56+ cells was noted in TpC+ subjects without liver disease. Yet among post-transfusional (TfC+) subjects this was associated with chronic hepatitis. CONCLUSIONS: Peripheral blood suppressor/cytotoxic T lymphocytes are increased, whereas activated helper/inducer T lymphocytes and NK cells are reduced, in renal allograft recipients with HCV infection. Increased non-MHC-restricted cytotoxic T cells and reduced NK cells are associated with the presence or absence of liver disease respectively. These data suggest that immune mechanisms are important in the pathogenesis of chronic hepatitis C after renal transplantation.

Adult↗
PubMed1999

Imbalance between cell proliferation and cellular DNA fragmentation in hepatocellular carcinoma.

AIM/BACKGROUND: Hepatocellular carcinoma (HCC) is known for its rapid growth. This study was undertaken to determine the expression of proliferative markers, apoptosis (DNA fragmentation) and oncogene products known to regulate apoptosis (p53, bcl-2) in HCC. METHODS: 150 Chinese patients with HCC were studied (M:F 128:22, age 14-88 years). Immunohistochemistry was employed to detect cell proliferative markers (PCNA, Ki67), and oncogene products known to regulate apoptosis (p53, bcl-2). DNA fragmentation was determined by terminal dUTP nick end labeling (TUNEL). RESULTS: 98% and 95% of HCC had PCNA (median 2+) and Ki67 (median 2+) detected respectively. TUNEL labeling was detected in only a small number of tumor cells (no labeling in 11%, median 1/1000 cell labeled, range: 0-70/1000 cells). There was no correlation between TUNEL labeling and the clinical parameters (sex, age, cirrhosis, and survival) and the expression of cell proliferative markers. p53 was detected in 53% of the patients (median 1+, range: 0-4+) and bcl-2 was detected in a small proportion of tumor cells in only 13% of the HCCs (range: 0-1 +). The expression of p53 and Bcl-2 did not correlate with TUNEL labeling or the natural survival. CONCLUSIONS: Cell proliferation in HCC is unmatched by apoptosis, accounting for the rapid growth of this tumor. This lack of apoptosis in HCC is unrelated to the expression of p53 or bcl-2 over-expression.

Adolescent↗
PubMed1999

Nucleic acid-based cross-linking assay for detection and quantification of hepatitis B virus DNA.

A nucleic acid photo-cross-linking technology was used to develop a direct assay for the quantification of hepatitis B virus (HBV) DNA levels in serum. Cross-linker-modified DNA probes complementary to the viral genomes of the major HBV subtypes were synthesized and used in an assay that could be completed in less than 6 h. The quantification range of the assay, as determined by testing serial dilutions of Eurohep HBV reference standards and cloned HBV DNA, was 5 x 10(5) to 3 x 10(9) molecules of HBV DNA/ml of serum. Within-run and between-run coefficients of variation (CVs) for the assay were 4. 3 and 4.0%, respectively. The assay was used to determine HBV DNA levels in 302 serum samples, and the results were compared to those obtained after testing the same samples with the Chiron branched-DNA (bDNA) assay for HBV DNA. Of the samples tested, 218 were positive for HBV DNA by both assays and 72 gave results below the cutoff for both assays. Of the remaining 12 samples, 10 were positive for HBV DNA by the cross-linking assay only; the 2 other samples were positive by the bDNA assay only. Twenty-eight samples had to be retested by the bDNA assay (CV, >20% between the results obtained from the testing of each sample in duplicate), whereas only three samples required retesting by the cross-linking assay. The correlation between the HBV DNA levels, as measured by the two tests, was very high (r = 0.902; P = 0.01). We conclude that the cross-linking assay is a sensitive and reproducible method for the detection and quantification of HBV DNA levels in serum.

Cross-Linking Reagents↗
PubMed1998

Prevalence and subtypes of dementia in southern Taiwan: impact of age, sex, education, and urbanization.

To determine the prevalence and subtypes of dementia in southern Taiwan, a two-phase study consisting of a phase I screening survey using the Mini-Mental Status Examination (MMSE) and a phase II diagnostic examination using the CERAD neuropsychological battery and the neurobehavioral examination was conducted. According to the household records, stratified random sampling by the degree of urbanization of the community was used, and 2915 inhabitants aged 65 and over participated in this study. The ICD-10NA criteria for dementia, NINCDS-ADRDA guidelines for Alzheimer's disease (AD), and NINDS-AIREN criteria for vascular dementia (VaD) were employed. Three hundred and ninety-eight persons who had MMSE scores below the cutoff values were recruited into the phase II study, of whom 108 had dementia. The prevalence rate (PR) of dementia was 3.7%, increasing from 1.3% in people 65-69 years old to 16.5% in people 85 years old and older. The age-standardized PR (ASPR) was 4.0%. AD (58 cases, 53.7%, PR=2.0%, ASPR=2.3%) was the most common cause of dementia, followed by VaD (25 cases, 23.1%, PR=0.9%, ASPR=0.9%), and mixed dementia (eight cases, 7.4%). After adjusting for age, sex and education using logistic regression analysis, aging was a significant risk factor for AD, VaD and total dementia. Female sex and illiteracy were significant risk factors for AD only. We concluded that the prevalence of dementia in Taiwan is lower than in the developed countries, which could be due to a relatively young elderly population and a high mortality from dementia in Taiwan. AD is the leading cause of dementia in Taiwan. Considering the high stroke prevalence, the relatively lower prevalence of VaD in Taiwan deserves further investigation.

Age Distribution↗
PubMed1998

A one-year trial of lamivudine for chronic hepatitis B. Asia Hepatitis Lamivudine Study Group.

BACKGROUND AND METHODS: In preliminary trials, lamivudine, an oral nucleoside analogue, has shown promise for the treatment of chronic hepatitis B. We conducted a one-year, double-blind trial of lamivudine in 358 Chinese patients with chronic hepatitis B. The patients were randomly assigned to receive 25 mg of lamivudine (142 patients), 100 mg of lamivudine (143), or placebo (73) orally once daily. The patients underwent liver biopsies before entering the study and after completing the assigned treatment regimen. The primary end point was a reduction of at least two points in the Knodell necroinflammatory score. RESULTS: Hepatic necroinflammatory activity improved by two points or more in 56 percent of the patients receiving 100 mg of lamivudine, 49 percent of those receiving 25 mg of lamivudine, and 25 percent of those receiving placebo (P<0.001 and P=0.001, respectively, for the comparisons of lamivudine treatment with placebo). Necroinflammatory activity worsened in 7 percent of the patients receiving 100 mg of lamivudine, 8 percent of those receiving 25 mg, and 26 percent of those receiving placebo. The 100-mg dose of lamivudine was associated with a reduced progression of fibrosis (P=0.01 for the comparison with placebo) and with the highest rate of hepatitis B e antigen (HBeAg) seroconversion (loss of HBeAg, development of antibody to HBeAg, and undetectable HBV DNA) (16 percent), the greatest suppression of HBV DNA (98 percent reduction at week 52 as compared with the base-line value), and the highest rate of sustained normalization of alanine aminotransferase levels (72 percent). Ninety-six percent of the patients completed the study. The incidence of adverse events was similar in all groups, and there were few serious events. CONCLUSIONS: In a one-year study, lamivudine was associated with substantial histologic improvement in many patients with chronic hepatitis B. A daily dose of 100 mg was more effective than a daily dose of 25 mg.

Adolescent↗
PubMed1998

The role of hepatic arterial embolization in the treatment of spontaneous rupture of hepatocellular carcinoma.

Thirty-three patients presenting with spontaneous rupture of hepatocellular carcinomas (HCCs) were referred for emergency transcatheter arterial embolization. Blood was present in the ascitic fluid on abdominal paracentesis in all 33 patients. Seventeen patients underwent emergency computed tomography (CT). HCCs were demonstrated on CT in all 17 patients. Blood was detected in the peritoneal cavity or around the liver surface on CT in 15 patients (88.2%), one of whom also had active extravasation of the contrast medium into the peritoneal cavity. Vascular tumours were present in the hepatic angiograms prior to embolization in all 33 patients but extravasation of the contrast medium from the HCC was seen on angiography in only six patients (18.2%). Bleeding from the ruptured HCC was stopped at the end of the procedure in 32 patients who had undergone successful embolization. The overall median survival time was 9 weeks. The median survival time of patients with a serum total bilirubin level of 50 micromol/l or below was 15 weeks, while that of patients with a serum total bilirubin level above 50 micromol/l was only 1 week, the difference being statistically significant. Embolization is therefore the treatment of choice in arresting life-threatening bleeding in ruptured HCC in patients with a serum total bilirubin level of 50 micromol/l or below, but the procedure is rarely effective in prolonging survival in patients with a serum total bilirubin above this critical level.

Adult↗
PubMed1998

Treatment of fibrosing cholestatic hepatitis with lamivudine.

Fibrosing cholestatic hepatitis is a histological variant of hepatitis B virus infection with a high rate of mortality. We describe a patient who acquired acute hepatitis B virus infection 8 months after renal transplantation. Clinical features of rapidly progressive liver failure, indicated by prolonged prothrombin time (57 seconds) and increased bilirubin (40.4 mg/dL) and ammonia (129 mumol/L) concentrations, were accompanied by an extremely high serum HBV DNA level (2.153 x 10(6) pg/mL). Liver biopsy specimen showed fibrosing cholestatic hepatitis with widespread balloon degeneration of hepatocytes, focal hepatocyte loss, bile stasis, periportal fibrosis, mild lymphocytic infiltration, and strongly positive immunohistochemical staining for hepatitis B surface antigen (HBsAg) and hepatitis B core antigen. Lamivudine therapy suppressed HBV DNA to < 10 pg/mL within 4 weeks, which was followed by gradual recovery of liver function from a state of hepatic precoma. Twenty-four months after the onset of hepatitis, the patient had normal prothrombin time and bilirubin, transaminase, and albumin levels. She remained HBsAg positive and hepatitis B e antigen negative. Renal allograft function was stable, with a creatinine level of 1.52 mg/dL. HBV DNA remained suppressed after 22 months of lamivudine therapy. Our experience shows that fibrosing cholestatic hepatitis and liver failure caused by HBV infection can be successfully treated with lamivudine.

Adult↗