Development of a lateral-flow immunochromatographic strip using gold nanoparticles for Helicobacter pylori detection.

Helicobacter pylori (H. pylori) plays an important role in the development of chronic gastritis, peptic ulcer diseases, gastric adenocarcinoma, and gastric mucosal associated lymphoid tissue (MALT) lymphoma. The standard methods of bacterial staining, bacterial culture, and urease testfor the detection of H. pylori are time consuming and invasive. Non-invasive testing plays a significant role in the test-and-treat approach to H. pylori management. Lateral flow immunoassay (LFIA) is a promising method for pathogenic detection that is fast, easy to use, and low cost. In the present study, the authors developed an H. pylori LFIA strip using gold nanoparticles for H. pylori detection. The results reported that 20 µg of anti-H. pylori antibody mixed with 1 mL AuNPs solution and incubated for 2 hours was the best concentration preparation for application coverage over the gold nanoparticle surface. The limit of detection observable by the naked eye was 15 µg of H. pylori protein lysate. The findings of this study suggest the possible future development of an H. pylori LFLA strip for fast, easy to use, and low-cost diagnostic testing.

An evaluation of a new in-house serum and urine ELISA test for detection of Helicobacter pylori infection in Thai population.

OBJECTIVE: Non-invasive tests play significant roles in the test-and-treat approach of Helicobacter pylori management. The detection of Helicobacter pylori antibodies in urine and serum is an easy and inexpensive way to diagnose this infection. In the present study, the authors developed an in-house serum and urine ELISA tests for H. pylori antibodies and evaluated their performance in a Thai population. MATERIAL AND METHOD: One hundred thirty eight dyspeptic patients were recruited. All subjects underwent upper endoscopy and one antral biopsy was obtained for rapid urease test, which was used as a standard reference. Urine and serum samples were collected before the procedure to run in-house ELISA test. RESULTS: Thirty (22%) subjects were positive for the rapid urease test and 108 (78%) were negative. Urine and serum optical density were significantly lower in the urease negative group (p = 0.011 and p < 0.001 respectively), while there were no differences in age, gender, or endoscopic findings between the two groups. Sensitivity, specificity, negative predictive value, positive predictive value, and accuracy of urine and serum ELISA tests were 72% vs. 96.3%, 63.5% vs. 627%, 89.6% vs. 98.5%, 33.3% vs. 40.6%, and 64.5% vs. 69.8% respectively. CONCLUSION: In-house serum ELISA test for H. pylori antibodies yielded a very good sensitivity with acceptable specificity, whereas urine ELISA was unable to produce satisfactory sensitivity or specificity

Immunogenicity and safety of a pediatric dose virosomal hepatitis A vaccine in Thai HIV-infected children.

The immunogenicity and safety of a pediatric dose of a virosomal hepatitis A vaccine (Epaxal®) was evaluated in a group of 45 Thai children with human immunodeficiency virus (HIV) infection, age 2-16 years. Vaccines were administered at 0 and 6 months. Anti-HAV antibody titers were measured at baseline (before injection) 1 and 7 months after primary vaccination. The prevalence of HAV protective antibody in 45 Thai HIV-infected children was 13.6%. The seroprotection rate was 71% at 1 month and 100% at 7 months. The booster dose increased geometric mean concentration (GMC) from 106.5 mIU/ml to 3486.1 mIU/ml. Higher CD4 lymphocyte counts at enrollment was a predictive factor for HAV antibody response. Both doses of Epaxal® were well tolerated. These preliminary data suggest that a pediatric dose of Epaxal® is an effective hepatitis A vaccine for HIV-infected children and should be considered for implementation on a larger scale in the pediatric HIV population.

Association of High Sensitivity C-Reactive Protein Concentrations and Metabolic Syndrome among Thai Adults.

OBJECTIVE: To investigate the association of high sensitivity C-reactive protein (hsCRP) concentrations and metabolic syndrome among Thai adults. METHODS: This cross-sectional study is comprised of 467 Thai participants (209 men and 258 women) receiving annual health check-up. Spearman's rank correlation coefficients were used to assess associations of metabolic parameters (age, waist circumference, blood pressure, triglycerides, HDL-C, fasting plasma glucose, fasting insulin and uric acid) with hsCRP concentrations for men and women, respectively. Multivariable logistic regression procedures were used to estimate the risk (odds ratios [OR] and 95% confidence intervals [95% CI]) of metabolic syndrome according to low, moderate and high hsCRP concentrations (<1.0, 1.0-3.0 and >3.0 mg/l, respectively). RESULTS: Measures of adiposity and fasting insulin were positively and significantly correlated with hsCRP concentrations among women with and without metabolic syndrome. Similar associations were observed among men without metabolic syndrome. After controlling for confounders, moderately elevated hsCRP concentrations were associated with a 2.38-fold increased risk of metabolic syndrome (OR=2.38, 95% CI: 1.20-4.72) among men. Men with high hsCRP concentrations had a 5.45-fold increased risk of metabolic syndrome (OR=5.45, 95% CI: 2.24-13.27) when compared with those who had low hsCRP concentrations. The corresponding odds ratios for women with moderately elevated and high hsCRP concentrations were 4.92 (OR=4.92, 95% CI: 2.34-10.35) and 11.93 (OR=11.93, 95% CI: 5.54-25.72), respectively. CONCLUSIONS: These findings are consistent with the literature suggesting a role of hsCRP as a biomarker for metabolic syndrome.

A simple efficient technique of 'mid-dilution' on-line hemodiafiltration.

BACKGROUND: On-line hemodiafiltration (OL-HDF) with pre- as well as post-dilution reinfusion mode provides superior uremic toxin removal, especially middle uremic toxins, and can improve patient survival. Both standard pre- and post-dilution have limitations. Mid-dilution OL-HDF (Nephros OLpur) was invented to overcome the disadvantages of both standard modes, but such a cartridge is only available in limited centers and is expensive. METHODS: We created a simple technique of mid-dilution OL-HDF that can be easily set up in every hemodialysis center. Twelve stable end-stage renal disease patients were dialyzed in a random sequence with three different infusion modes of OL-HDF (simple mid-dilution, standard pre-dilution and post-dilution). Small molecule, middle molecule, and protein-bound uremic toxin clearances were measured. RESULTS: Simple mid-dilution OL-HDF provided high efficiency in uremic toxin clearances with less protein loss. CONCLUSION: Simple mid-dilution OL-HDF combines the advantages of pre- and post-dilution modes without adverse effects. Thus, this technique could be useful in decreasing morbidity and mortality in hemodialysis patients.

Evaluation of Helicobacter pylori stool antigen test in Thai patients with upper gastrointestinal bleeding.

OBJECTIVE: Stool antigen test was evaluated in comparison with other diagnostic tests for the diagnosis of H. pylori infection in Thai patients presented with upper gastrointestinal bleeding. MATERIAL AND METHOD: Fifty-six patients were enrolled and fecal specimen was obtained from 34 patients. The presence of H. pylori was considered if the culture was positive or at lease two of the other diagnostic tests (urea breath test, serology, rapid urease test or histology) were positive. Stool antigen test was performed by using commercially available monoclonal enzyme immunoassay (Amplified IDEIA HpStAR, Dako, Denmark). RESULTS: Of the 56patients, 35 (62.5%0) were considered H. pylori infected, while in 34patients tested by stool antigen test, 22 (64.71%) were infected. The prevalence of H. pylori infection as determined by each test is considered low (47.06% from stool antigen test; 42.50%from UBT, 65.85%from serology; 51.78%0from RUT- and 46.34% from histology). The sensitivity/specificity/accuracy (%) of stool antigen test was 69.56/100/ 79.41 compared to 73.91/100/85 of UBT 79.17/52.94/68.29 of serology, 80/95.23/85.71 of RUT and 82.61/ 100/90.24 of histology, respectively. CONCLUSION: In summary, the results of this study reveal that the prevalence of H. pylori was relatively low in upper gastrointestinal bleeding patients. Yielding a low sensitivity and accuracy, the stool antigen test is therefore not reliable for the diagnosis of H. pylori infection in patients with upper gastrointestinal bleeding.

Prevalence of positive antinuclear antibodies in healthy children.

Antinuclear antibodies (ANA) frequently arise in the sera of children with connective tissue disease and is used in the diagnosis of these diseases. Therefore it is also important to know the prevalence of ANA in normal children. The main objective of the present study was to determine the prevalence of antinuclear antibody (ANA) in healthy children. Ninety-nine serum samples from a serum bank and 108 samples from patients who had attended elective surgery and whose blood had been withdrawn for other investigations, were tested for ANA by indirect immunofluorescence method using HEp-2 cells as substrate. Sera from 52 children with SLE were also tested during the same period. It was found that antinuclear antibodies were present in 32 (15%) of the 207 sera of healthy children at a dilution of 1:40 or higher. ANA were positive in 9% at a serum dilution of 1:40, in 3% at 1:80 and in 3% at 1:160. The patterns of immunofluorescence staining were as follows: homogeneous in 46.7%, speckled in 20%, and nucleolar in 10%. In SLE patients, ANA were positive in 91%; 13% at a serum dilution of 1:40, 7% at 1:80, 20% at 1:160, 15% at 1:320, 9% at 1:640, 20% at 1:1,280 and 9% at > or = 1:2,560. It was concluded that the prevalence of positive ANA using the HEp-2 cells as substrate was 15% in healthy children at dilutions of 1:40 or higher. Using the cutoff serum dilution of 1:40, the sensitivity of this test was 91%, the specificity was 85%, the positive predictive value was 57% and the negative predictive value was 97%.

Analysis of eight different methods for the detection of Helicobacter pylori infection in patients with dyspepsia.

BACKGROUND: The present study was designed to compare the accuracy of eight different methods for the detection of Helicobacter pylori (H. pylori) infection in patients with dyspepsia. These tests included culture, histology, rapid urease test (CLO test), serology, saliva IgA, gastric juice IgA, and two in-house methods, namely in-house urease test and Gram stain. METHODS: H. pylori infection was diagnosed prospectively in 200 untreated patients who underwent upper gastrointestinal endoscopy at King Chulalongkorn Memorial Hospital, Bangkok, Thailand, between July 1999 and August 2001. The gold standard for H. pylori infection was based on a positive culture or both a positive histological examination and CLO test. RESULTS: The culture provided a sensitivity of 55.9% whereas saliva IgA and gastric juice IgA had a sensitivity of 26.8% and 22.2%, respectively. In contrast, the other tests provided satisfactory sensitivities ranging between 89.3% and 100% (Gram stain 89.3%, histology 93.5%, serology 96.8%, CLO test 99.0%, in-house urease test 100%). The specificities of the tests ranged between 75% and 100% (culture 100%, CLO test 91.9%, histology 90.4%, in-house urease test 88.9%, Gram stain 93.5% serology 96.8%, gastric juice IgA 91.7% and saliva IgA 75%). CONCLUSIONS: Majority of invasive and non-invasive tests in this study were accurate for the diagnosis of H. pylori infection. However, the secretory IgA-based techniques in saliva and gastric juice seem to be inappropriate for determining H. pylori status in our populations due to their low sensitivities.

Evaluation of commercial immunoassays for detection of antibody against Helicobacter pylori in Thai dyspeptic patients.

The performance of five immunoassays for detection of immunoglobulin G antibody against Helicobacter pylori in 191 dyspeptic patients was evaluated. The sensitivities, specificities, accuracies, positive predictive values, and negative predictive values ranged from 86.32 to 97.89%, 57.95 to 72.22%, 77.02 to 83.76%, 71.54 to 77.42%, and 83.33 to 96.23%, respectively. The immunoglobulin A test kit also gave a high sensitivity and negative predictive value (95.79 and 91.40%, respectively), while the specificity was relatively low (51.14%).

Diagnostic role of serum interleukin 6 and CA 19-9 in patients with cholangiocarcinoma.

BACKGROUND/AIMS: Cholangiocarcinoma is particularly common in Northeastern Thailand where the liver fluke, O. viverrini, is endemic. Currently there is no sensitive and specific tumor marker for the diagnosis of this cancer. The aim of this study was to investigate the accuracy of carbohydrate antigen 19-9 and interleukin-6 in the diagnosis of cholangiocarcinoma. The first marker represents the commonly used serum marker in cholangiocarcinoma and the second marker is a multi-functional cytokine associated with cancer development. METHODOLOGY: The serum concentrations of carbohydrate antigen 19-9 and interleukin-6 were simultaneously determined in 45 patients with cholangiocarcinoma, 15 with hepatocellular carcinoma, 15 with metastatic liver cancers, 10 with benign biliary disease and 10 healthy controls. RESULTS: The sensitivity of carbohydrate antigen 19-9 value (> or = 37 U/mL) in diagnosing cholangiocarcinoma was 64.4%, while its specificity was 100% and 56.7% when compared with benign biliary disease and other liver cancers, respectively. The sensitivity and specificity of detectable interleukin-6 (> or = 0.18 ng/mL) for differentiating between cholangiocarcinoma and benign biliary disease was 71.1% and 90%, respectively, whereas the specificity for differentiating cholangiocarcinoma from other liver cancers was 26.7%. When higher concentrations of either carbohydrate antigen 19-9 (> or = 100 U/mL) or interleukin-6 (> or = 50 pg/mL) were used as the cut-off points, they provided additional diagnostic sensitivity and accuracy in differentiating between cholangiocarcinoma and other liver cancers to 80% and 76%, respectively. CONCLUSIONS: The combined assays of both serum carbohydrate antigen 19-9 and interleukin-6 could be useful in diagnosing cholangiocarcinoma, particularly in populations where this cancer is prevalent.

Prevalence of autoantibodies in Thai elderly.

To investigate the prevalence of autoantibodies in a normal Thai elderly group, the authors measured anti-thyroid antibodies (anti-thyroglobulin, anti-thyroid microsome), antinuclear antibodies (ANA) and rheumatoid factors (RF) in 429 normal elderly (206 men, 223 women, age range 50-102 years). The participants recruited from Romklao Village, Lat Krabang, a suburb of Bangkok and compared to 219 young normal subjects (110 men, 109 women; age range 19-49 years). The prevalence of anti-thyroid antibodies was significantly increased in the elderly group when compared to the younger age control group (14.69% vs 5.02%, p = 0.0005). The antibody titers were found to be higher and the prevalence was more predominant in women than in men both in the elderly (21.53% vs 7.28%, p = 0.00005) and control groups (10.09% vs 0%, p = 0.0018). The prevalence of ANA in the elderly group was lower (1.17%) when compared to the control group (4.11%). ANA were characterized by low titer of antibodies and several staining patterns, and there was no difference between men and women. For RF, the prevalence was almost the same in both groups (2.79% in the elderly and 2.73% in control group) and no difference was observed. However, when all the three autoantibodies were considered, 20.28 per cent of the elderly individuals were found to have at least one of the autoantibodies which was significantly higher than in the younger control group (11.41%, p = 0.006). The prevalence was more predominant in women than in men. The results from this study can be used as basic data for the evaluation of autoantibodies testing in an elderly Thai population.

Evaluation of inhouse rapid urease test for detection of Helicobacter pylori from gastric biopsy specimens.

Inhouse rapid urease test for detecting Helicobacter pylori was evaluated. Biopsy specimens were taken for inhouse urease test, commercial rapid urease CLO test, culture, gram stain and histology from the antrium or duodenum of patients who had peptic ulcer. The culture and/or histologic examination and CLO test were used as the gold standard. One hundred and twelve specimens were evaluated. The sensitivity and specificity of the inhouse urease test was 100 per cent and 90 per cent respectively. The inhouse urease test was suitable for detecting Helicobacter pylori from gastric antral biopsy specimens. The medium can be kept in a refrigerator for up to 6 months.

Detection of antibody in serum and secretion for the diagnosis of Helicobacter pylori infection.

Helicobacter pylori plays a major role in chronic gastritis and peptic ulcer. In addition, it has been shown to be associated with gastric carcinoma. In this study, the authors compared the detection of IgG antibodies specific to H. pylori by enzyme-immunoassay with culture, histology and a CLO test as tools for diagnosis of H. pylori infection. If the criteria that patients will be considered as H. pylori infected only when their samples are positive by culture or CLO test and histology were used, the sensitivity and specificity of detecting IgG in sera were 96.84 and 72.04 per cent respectively. The use of serological test will be useful as a screening test for H. pylori infection without the need of endoscopy. The authors also performed the assay for detecting IgA antibodies in saliva and gastric juice. The sensitivity and specificity of IgA detection in saliva were 26.79 per oent and 75.00 per cent. As for the assay in gastric juice, although the specificity was as high as 91.67 per cent, the sensitivity is very low (22.22%).