Development and validation of reverberation-chamber type whole-body exposure system for mobile-phone frequency.

We developed whole-body exposure systems for in-vivo study at cellular (848.5 MHz) and Personal Communication System (PCS, 1,762.5 MHz) frequency, utilizing reverberation chamber. The field uniformities in the test area of the designed chambers were verified by simulation and measurement. In the whole-body exposure environment, Specific Absorption Rate (SAR) distributions inside of mice were calculated using Finite Difference Time Domain (FDTD) simulation. Key results are presented in this article.

Oral immunization with Helicobacter pylori-loaded poly(D, L-lactide-co-glycolide) nanoparticles.

BACKGROUND: Helicobacter pylori is a major cause of chronic antral gastritis and peptic ulcer diseases. Many researchers have examined the possibility of immunologically-mediated prevention of H. pylori infection using an oral vaccine. The purpose of this study is to investigate whether mucosal and systemic immune responses are induced by oral immunization with H. pylori lysate-loaded poly(D, L-lactide-coglycolide)[PLG] nanoparticles, and if so, how the distribution of serum IgG subclasses are produced. METHODS: PLG nanoparticles (H. pylori-PLG) with encapsulated H. pylori lysates were prepared by the solvent evaporation method, and the physical properties of the nanoparticles were investigated. Following the oral immunization of the H. pylori-PLG nanoparticles into mice, antibody induction was assayed in serum and gut washings, and the pattern of serum IgG subclasses was determined by ELISA. RESULTS: The prepared H. pylori-PLG nanoparticles were spherical, nonporous particles with a mean diameter of less than 1 microm. The multiple oral immunization with H. pylori-PLG nanoparticles induced significantly H. pylori-specific mucosal IgA response as well as serum IgG responses. The serum antibody subclasses elicited were predominantly IgG1 and IgG2b. CONCLUSION: Our results suggested that oral immunization of H. pylori-PLG nanoparticles induced the H. pylori-specific mucosal and systemic responses in mice and enhanced Th2-type responses.

Induction of mucosal and systemic immune response by oral immunization with H. pylori lysates encapsulated in poly(D,L-lactide-co-glycolide) microparticles.

Helicobacter pylori is a major cause of chronic antral gastritis and peptic ulcer diseases. Several kinds of poly(D,L-lactide-coglycolide) microparticles containing H. pylori whole-cell lysate (PLG-HP) were prepared by the solvent evaporation method using double emulsion. Physical properties, such as particle size, protein content, and morphology were investigated. All prepared microparticles showed a smooth surface morphology from 0.5-0.86 microm in diameter and high degree of encapsulation efficiency from 62-75%. SDS-PAGE and immunoblotting of extracted antigen confirmed that the molecular weight and antigenicity of the antigen remained unaltered by the encapsulation procedure. Following the oral immunization of the microparticles to mice, antibody production was assayed in serum and gut washings by ELISA and antibody secreting cells were determined in intestinal lamina propria lymphocytes (LPL) by ELISPOT. Multiple oral immunizations induced significant H. pylori-specific intestinal IgA response as well as serum IgG response than those detected with soluble antigen (P < 0.001). The presence of antibody-secreting cell in intestinal lamina propria lymphocytes (LPL) was correlated with IgA level in gut washing fluids. After boosting at week-8, the antibody induction levels were highly increased irrespective of microparticles prepared with different PLG molecular weights. These data suggested that PLG-HP could stimulate the H. pylori-specific mucosal and systemic response in vivo and might be useful adjuvant in future H. pylori vaccine development.

Serodiagnosis of Helicobacter pylori infection in Korean patients using enzyme-linked immunosorbent assay.

Helicobacter pylori (H. pylori) is a gram-negative spiral bacteria that are associated with gastritis, peptic ulcer and gastric cancer. We have developed enzyme-linked immunosorbent assay (ELISA) that detects serum anti-H. pylori immunoglobulin G antibodies using H. pylori strains isolated from Korean patients. To assess the sensitivity and specificity of our assay system with different commercial kits, serum samples from 249 Korean patients with a variety of gastrointestinal diseases were tested. Among 249 Korean patients, 178 (71.5%) were positive in culture and/or urease test. The sensitivity and specificity between our assay system and four other commercial kits (Bio-Rad, DAKO, ROCHE, and IPR) were as follows: 97.8% and 92%, 94.3% and 53%, 56.5% and 92%, 83.3% and 96%, 58.2% and 92%, respectively. All sera showing discordant immunoassay results between different ELISA kits were confirmed by immunoblot analysis. These results indicate that our assay system showed a highly accurate and reliable results in diagnosis of H. pylori infection in Korean patients.

Rapid purification and characterization of nucleoside diphosphate kinase isoforms using ATP-sepharose affinity column chromatography.

Nucleoside diphosphate kinases (NDP kinases), products of the nm23 gene, catalyze the transfer of the terminal phosphate group of the nucleoside triphosphate to the corresponding diphosphate and may be involved in tumor metastasis suppression, development, and signal transduction. NDP kinase from various sources including human erythrocytes, rat brain tissue and E. coli strain BL21 transformed with pET3C expression plasmids containing nm23-H1 or nm23-H2, were purified in one step to homogeneity using ATP-sepharose affinity column chromatography. This method was applicable for the purification of various NDP kinases which show the same enzymatic activity and immunodetection, but have various molecular weight and quaternary structures.

Quantitative analysis of serum proteins separated by capillary electrophoresis.

The possibility of open tubular capillary electrophoresis for clinical diagnostic use is examined. Capillary electrophoresis was performed in an untreated 50 microns (i.d.) x 100 cm (65 cm to detector) capillary with detection of absorbance at 200 nm. Conditions for the separation of serum proteins without adsorption to the capillary surface were established. Quantitative analyses of serum samples from 38 patients with liver cirrhosis, nephrotic syndrome, or polyclonal gammopathy by capillary electrophoresis were done and the results were compared with those by conventional agarose gel electrophoresis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. All samples were analyzed in duplicate. We evaluated linearity of response, within-run CV, and the correlation between capillary electrophoresis and agarose gel electrophoresis.