Clinical impact of major pathogenic genotypes of Pseudomonas aeruginosa associated with refractory chronic suppurative otitis media.

PURPOSE: Chronic suppurative otitis media (CSOM) is characterized by persistent inflammation of the mucous membrane of the middle ear and mastoid. One of the primary causative agents of CSOM is P. aeruginosa, known for its production of virulent toxins and enzymes. Some cases of CSOM, improvement may not occur despite treatment lasting three weeks, leading to what is termed refractory CSOM. This research aims to characterize the P. aeruginosa strains isolated from patients with refractory CSOM in Gyeongsangnam-do, South Korea, providing insights into their pathogenic profiles. METHODS: We conducted a retrospective analysis of P. aeruginosa isolates from the otorrhea of patients diagnosed with CSOM at a tertiary hospital in Gyeongsangnam-do, over a period from January 2005 to August 2022. The strains were examined using multilocus sequence typing (MLST) and toxin gene assay to assess genetic diversity and virulence. RESULTS: 39 samples were obtained from 13 cases of refractory CSOM and 15 cases of non-refractory CSOM. The findings unveiled that the P. aeruginosa cultured from patients with refractory CSOM belonged to the P. aeruginosa sequence type 235 (ST235) strain, which harbors the exoU gene as a major virulence factor. CONCLUSION: The detection of ST235 in refractory CSOM signifies a challenging clinical scenario. Given the genotype's strong virulence and antibiotic resistance, identifying ST235 through MLST can guide effective management approaches, including potential surgical intervention. This study underscores the necessity of broader epidemiological investigations to understand ST235 behavior and advocates for patient education to mitigate the impacts of this formidable pathogen in CSOM.

Prevalence and virulence profiles of ESBL-producing Escherichia coli in urinary and blood infections in South Korea.

Escherichia coli is a significant pathogen in extraintestinal infections, and ESBL-producing E. coli poses a major clinical challenge due to its antibiotic resistance. This study comprehensively analyzed E. coli isolates from urine and blood samples of patients with urinary tract and bloodstream infections at three major tertiary hospitals in South Korea. The goal was to provide insights into the distribution, antibiotic resistance, and virulence factors of these strains. Our analysis identified CTX-M and TEM as the dominant ESBL types, found in 71.7% and 61.7% of isolates, respectively, with 46.7% showing co-occurrence. Multilocus sequence typing (MLST) revealed the predominance of high-risk clones such as ST131, ST69, ST73, and ST95, with rare sequence types like ST410 and ST405 also identified. The high prevalence of virulence factors, including iutA (80.8%) and kpsMII (74.2%), further highlights the complexity of these strains. In addition, 38.3% of clinical isolates contained a combination of siderophore, adhesin, protectin, and toxin-related genes. There was no significant difference between urinary tract and bloodstream infections or regional differentiation in Korea. This study highlights the importance of controlling ESBL-producing E. coli infections, especially given the increasing incidence among patients with underlying medical conditions and older adults who are more susceptible to urinary tract infections. These findings serve as valuable indicators for pathogen analysis, especially those harboring antibiotic resistance and toxin genes. The insights gained are expected to contribute significantly to the development of infectious disease prevention and control strategies.

Identification of Autoantigens in Pediatric Gastric Juices.

Purpose: This study aimed to investigate the presence of autoantigens in the gastric juices of children. Methods: Gastric juice and serum samples were obtained from 53 children <15 years of age who underwent gastric endoscopy. Among these, 8, 22, and 23 participants were in the age groups 0-5, 6-10, and 11-15 years, respectively. These samples were analyzed using two-dimensional electrophoresis (2-DE), immunoblot analysis, and matrix-assisted laser desorption ionization-time of-flight mass spectrometry. Furthermore, we reviewed the histopathological findings and urease test results and compared them with the results of 2-DE and immunoblot analysis. Results: There were no statistically significant differences in urease test positivity, grades of chronic gastritis, active gastritis, or Helicobacter pylori infiltration of the antrum and body among the three age groups. Three distinct patterns of gastric juice were observed on 2-DE. Pattern I was the most common, and pattern III was not observed below the age of 5 years. Histopathological findings were significantly different among active gastritis (p=0.037) and H. pylori infiltration (p=0.060) in the gastric body. The immunoblots showed large spots at an approximate pH of 3-4 and molecular weights of 31-45 kDa. These distinct, large positive spots were identified as gastric lipase and pepsin A and C. Conclusion: Three enzymes, which are normally secreted under acidic conditions were identified as autoantigens. Further investigation of the pathophysiology and function of autoantigens in the stomach is required.

A novel repeat sequence-based PCR (rep-PCR) using specific repeat sequences of Mycobacterium intracellulare as a DNA fingerprinting.

Repetitive sequence-based PCR (rep-PCR) is a potential epidemiological technique that can provide high-throughput genotype fingerprints of heterogeneous Mycobacterium strains rapidly. Previously published rep-PCR primers, which are based on nucleotide sequences of Gram-negative bacteria may have low specificity for mycobacteria. Moreover, it was difficult to ensure the continuity of the study after the commercial rep-PCR kit was discontinued. Here, we designed a novel rep-PCR for Mycobacterium intracellulare, a major cause of nontuberculous mycobacterial pulmonary disease with frequent recurrence. We screened the 7,645 repeat sequences for 200 fragments from the genome of M. intracellulare ATCC 13950 in silico, finally generating five primers with more than 90% identity for a total of 226 loci in the genome. The five primers could make different band patterns depending on the genome of three different M. intracellulare strains using an in silico test. The novel rep-PCR with the five primers was conducted using 34 bacterial samples of 7 species containing 25 M. intracellulare clinical isolates, compared with previous published rep-PCRs. This shows distinguished patterns depending on species and blotting assay for 6 species implied the sequence specificity of the five primers. The Designed rep-PCR had a 95-98% of similarity value in the reproducibility test and showed 7 groups of fingerprints in M. intracellulare strains. Designed rep-PCR had a correlation value of 0.814 with VNTR, reference epidemiological method. This study provides a promising genotype fingerprinting method for tracing the recurrence of heterogeneous M. intracellulare.

Antigenic Determinant of Helicobacter pylori FlaA for Developing Serological Diagnostic Methods in Children.

The early diagnosis of Helicobacter pylori infection is important for gastric cancer prevention and treatment. Although endoscopic biopsy is widely used for H. pylori diagnosis, an accurate biopsy cannot be performed until a lesion becomes clear, especially in pediatric patients. Therefore, it is necessary to develop convenient and accurate methods for early diagnosis. FlaA, an essential factor for H. pylori survival, shows high antigenicity and can be used as a diagnostic marker. We attempted to identify effective antigens containing epitopes of high diagnostic value in FlaA. Full-sized FlaA was divided into several fragments and cloned, and its antigenicity was investigated using Western blotting. The FlaA fragment of 1345-1395 bp had strong immunogenicity. ELISA was performed with serum samples from children by using the 1345-1395 bp recombinant antigen fragment. IgG reactivity showed 90.0% sensitivity and 90.5% specificity, and IgM reactivity showed 100% sensitivity and specificity. The FlaA fragment of 1345-1395 bp discovered in the present study has antigenicity and is of high value as a candidate antigen for serological diagnosis. The FlaA 1345-1395 bp epitope can be used as a diagnostic marker for H. pylori infection, thereby controlling various gastric diseases such as gastric cancer and peptic ulcers caused by H. pylori.

Fetuin as a potential serum biomarker to detect subclinical shedder of bovine paratuberculosis.

Paratuberculosis (PTB) is a chronic contagious granulomatous enteritis of wild and domestic ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP). PTB causes considerable economic losses to the dairy industry through decreased milk production and premature culling. PTB-affected cattle undergo a subclinical stage without clinical signs and initiate fecal shedding of MAP into the environment. Current diagnostic tools have low sensitivity for the detection of subclinical PTB infection. Therefore, alternative diagnostic tools are required to improve the diagnostic sensitivity of subclinical PTB infection. In this study, we performed ELISA for three previously identified host biomarkers (fetuin, alpha-1-acid glycoprotein, and apolipoprotein) and analyzed their diagnostic performance with conventional PTB diagnostic methods. We observed that serum fetuin levels were significantly lowered in the subclinical shedder and clinical shedder groups than in the healthy control group, indicating its potential utility as a diagnostic biomarker for bovine PTB. Also, fetuin showed an excellent discriminatory power with an AUC = 0.949, a sensitivity of 92.6%, and a specificity of 94.4% for the detection of subclinical MAP infection. In conclusion, our results demonstrated that fetuin could be used as a diagnostic biomarker for enhancing the diagnostic sensitivity for the detection of subclinical MAP infections that are difficult to detect based on current diagnostic methods.

Endoplasmic Reticulum Stress and Impairment of Ribosome Biogenesis Mediate the Apoptosis Induced by Ocimum x africanum Essential Oil in a Human Gastric Cancer Cell Line.

Background and Objectives: Gastric cancer remains a major unmet clinical problem worldwide. Although conventional medical treatments are available, their curative effects are generally unsatisfactory. Consequently, it remains necessary to search natural products for potential alternatives in treating gastric cancer patients. Ocimum x africanum Lour. is a culinary herb that has been used in folk medicine for various diseases, but little is known regarding its anti-cancer activity against gastric cancer cells. In the current study, we focus on the anti-cancer mechanisms of O. x africanum essential oil (OAEO) in the AGS human gastric cancer cell line. Materials and Methods: After OAEO treatment, AGS cell viability was evaluated by MTT assay. Cell migration and apoptotic nuclear morphology were determined by wound-healing assay and DAPI staining, respectively. Gene expression levels of apoptosis-related genes were quantified by qRT-PCR. Differential protein expression was determined with an LC-MS/MS-based proteomics approach to identify the key proteins that may be important in the anti-cancer mechanisms of OAEO on AGS cells. The chemical constituents of OAEO were identified by GC-MS analysis. Results: We found OAEO to exhibit a potent growth-inhibiting effect on AGS cells, with an IC50 value of 42.73 µg/mL. After OAEO treatment for 24 h, AGS cell migration was significantly decreased relative to the untreated control. OAEO-treated AGS cells exhibited common features of apoptotic cell death, including cell shrinkage, membrane blebbing, chromatin condensation, and nuclear fragmentation. Apoptotic cell death was confirmed by qRT-PCR for apoptosis-related genes, revealing that OAEO decreased the expression of anti-apoptotic genes (BCL2 and BCL-xL) and activated pro-apoptotic genes and apoptotic caspase genes (TP53, BAX, CASP9, CASP12, and CASP3). Moreover, expression of CASP8 was not changed after treatment. Proteomic analysis revealed that OAEO may produce a signature effect on protein clusters relating to unfolded protein accumulation, thereby inducing severe ER stress and also impairing ribosome synthesis. STRING analysis revealed seven up-regulated and 11 down-regulated proteins, which were significantly associated with protein folding and ribosome biogenesis, respectively. Using GC-MS analysis, 6-methyl-5-hepten-2-one, citral, neral, and linalool were found to be the major chemical constituents in OAEO. Conclusions: Taken together, these results indicate that OAEO has a potential anti-proliferative effect on AGS cells. Our molecular findings show evidence supporting an important role of ER stress and ribosome biogenesis impairment in mediating the induction of cell death by OAEO through the mitochondrial-apoptotic pathway. This study, therefore, provides fundamental knowledge for future applications using OAEO as an alternative therapy in gastric cancer management.

Heterogeneity of Helicobacter pylori bab genotypes and their association with clinical outcomes in Korean gastroduodenal patients.

In this study, we aimed to investigate the prevalence of bab genes (babA, babB, babC) at their three loci (loci A, B, and C) in Helicobacter pylori strains from varied clinical manifestations of Korean gastroduodenal patients. The overall prevalence of H. pylori Korean strains positive for babA and babB was 91.1% and 92.2%, respectively, but all strains were negative for bab C. H. pylori strains with two loci occupied (loci A and B) were the most prevalent in Korean patients (85.6%), compared to one locus occupied (14.4%) (locus A or B). Twelve bab genotypes were detected, additionally, the distribution of three bab genotypes was significantly associated with different clinical outcomes among Korean patients. The genotypes babA/babB/- and babA/babA+babB/- were significantly associated with peptic ulcer disease (PUD) (63.3%) and gastritis (GT) (33.3%) patients, respectively. In addition, we found that the babA+babB/babA+babB/- genotype was significantly associated with gastric cancer (GC) (36.7%) as compared to GT (6.7%) or PUD (6.7%) (p<0.05) patients. This study provided evidence that the bab genotypes in H. pylori Korean strains were highly variable. Interestingly, three patterns of bab genotypes were significantly different among patients with different clinical outcomes in the population at high-risk for GC.

An In Vitro Anti-Cancer Activity of Ocimum tenuiflorum Essential Oil by Inducing Apoptosis in Human Gastric Cancer Cell Line.

Background and Objectives: The effects of Ocimum tenuiflorum essential oil (OTEO) against gastric cancer remain unknown and merit investigation. Materials and Methods: In the present study, the anti-cancer activity of OTEO was examined in a human gastric cancer cell line (AGS). After OTEO treatment, AGS cell viability was determined by an MTT assay, and inhibition of metastasis was determined by cell migration and invasion assays. The expression of apoptosis-related genes in treated AGS cells was determined by qRT-PCR. Results: OTEO significantly decreased AGS cell viability in a dose-dependent manner (IC50 163.42 µg/mL) and effectively inhibited cell migration and invasion. Morphological examination demonstrated that OTEO induced cell shrinkage, chromatin condensation, and fragmentation, which are considered typical morphologies of apoptotic cell death. Pro-apoptotic genes (TP53, BAX, and BAK) were significantly up-regulated, while anti-apoptotic genes (BCL-2 and BCL-xL) were significantly down-regulated after treatment with OTEO. In addition, significantly increased gene expression was detected for CASP8, CASP9, and CASP3 in AGS cells exposed to OTEO. GC-MS analysis demonstrated that the major compound of OTEO was caryophyllene (25.85%) and α-pinene (11.66%). Conclusions: This in vitro study demonstrates for the first time that OTEO has potential anti-gastric cancer activity and may induce apoptosis in AGS cells through extrinsic and intrinsic pathways.

Identification of Nontuberculous Mycobacteria in Patients with Pulmonary Diseases in Gyeongnam, Korea, Using Multiplex PCR and Multigene Sequence-Based Analysis.

BACKGROUND: Nontuberculous mycobacteria (NTM) are widely present in environments, such as soil and water, and have recently been recognized as important pathogenic bacteria. The incidence of NTM-related infections is steadily increasing. As the diagnosis and treatment of NTM infection should be distinguished from tuberculosis, and the treatment should be specific to the species of NTM acquired, accurate species identification is required. METHODS: In this study, two-step multiplex PCR (mPCR) and multigene sequence-based analysis were used to accurately identify NTM species in 320 clinical isolates from Gyeongsang National University Hospital (GNUH). In particular, major mycobacterial strains with a high isolation frequency as well as coinfections with multiple species were diagnosed through two-step mPCR. Multigene sequencing was performed to accurately identify other NTM species not detected by mPCR. Variable regions of the genes 16S rRNA, rpoB, hsp65, and 16S-23S rRNA internal transcribed spacer were included in the analysis. RESULTS: Two-step mPCR identified 234 (73.1%) cases of M. intracellulare, 26 (8.1%) cases of M. avium subsp. avium, and 13 (4.1%) cases of M. avium subsp. hominissuis infection. Additionally, 9 (2.8%) M. fortuitum, 9 (2.8%) M. massiliense, 2 (0.6%) M. abscessus, and 4 (1.2%) M. kansasii isolates were identified. Coinfection was identified in 7 (2.2%) samples. The sixteen samples not classified by two-step mPCR included 6 (1.9%) cases of M. chimaera, 4 (1.3%) M. gordonae, 1 (0.3%) M. colombiense, 1 (0.3%) M. mageritense, and 1 (0.3%) M. persicum identified by sequence analysis. CONCLUSIONS: The results of this study suggest a strategy for rapid detection and accurate identification of species using two-step mPCR and multigene sequence-based analysis. To the best of our knowledge, this study is the first to report the identification of NTM species isolated from patients in Gyeongnam/Korea.

Alpha-2-Macroglobulin as a New Promising Biomarker Improving the Diagnostic Sensitivity of Bovine Paratuberculosis.

Johne's disease (JD) is a chronic granulomatous enteritis of ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP), which induces persistent diarrhea and cachexia. JD causes huge economic losses to the dairy industry due to reduced milk production and premature culling. Infected animals excrete MAP via feces during the prolonged subclinical stage without exhibiting any clinical signs. Therefore, accurate detection of subclinical stage animals is crucial for successful eradication of JD in the herd. In the current study, we analyzed serum samples of MAP-infected and non-infected cattle to identify potential biomarker candidates. First, we identified 12 differentially expressed serum proteins in subclinical and clinical shedder groups compared to the healthy control group. Second, we conducted ELISA for three selected biomarkers (alpha-2-macroglobulin (A2M), alpha-1-beta glycoprotein, and transthyretin) and compared their diagnostic performance with that of two commercial ELISA diagnostic kits. Serum A2M levels were significantly higher in the MAP-exposed, subclinical shedder, subclinical non-shedder, and clinical shedder groups than in the healthy control group, suggesting its possible use as a diagnostic biomarker for MAP infection. Furthermore, A2M demonstrated a sensitivity of 90.4%, and a specificity of 100% while the two commercial ELISA kits demonstrated a sensitivity of 67.83 and 73.04% and a specificity of 100%, respectively. In conclusion, our results suggest that measuring A2M by ELISA can be used as a diagnostic tool to detect MAP infection, considerably improving the detection rate of subclinical shedders and MAP-exposed animals that are undetectable using current diagnostic tools.

Increased Risk of Severe Gastric Symptoms by Virulence Factors vacAs1c, alpA, babA2, and hopZ in Helicobacter pylori Infection.

Two virulence factors of Helicobacter pylori, cagA and vacA, have been known to play a role in the development of severe gastric symptoms. However, they are not always associated with peptic ulcer or gastric cancer. To predict the disease outcome more accurately, it is necessary to understand the risk of severe symptoms linked to other virulence factors. Several other virulence factors of H. pylori have also been reported to be associated with disease outcomes, although there are many controversial descriptions. H. pylori isolates from Koreans may be useful in evaluating the relevance of other virulence factors to clinical symptoms of gastric diseases because the majority of Koreans are infected by toxigenic strains of H. pylori bearing cagA and vacA. In this study, a total of 116 H. pylori strains from Korean patients with chronic gastritis, peptic ulcers, and gastric cancers were genotyped. The presence of virulence factors vacAs1c, alpA, babA2, hopZ, and the extremely strong vacuolating toxin was found to contribute significantly to the development of severe gastric symptoms. The genotype combination vacAs1c/alpA/babA2 was the most predictable determinant for the development of severe symptoms, and the presence of babA2 was found to be the most critical factor. This study provides important information on the virulence factors that contribute to the development of severe gastric symptoms and will assist in predicting clinical disease outcomes due to H. pylori infection.

Comparative Evaluation of Band-Based Genotyping Methods for Mycobacterium intracellulare and Its Application for Epidemiological Analysis.

Mycobacterium intracellulare is a leading cause of nontuberculous mycobacterial pulmonary disease, with a rapidly increasing prevalence worldwide. This bacterium, commonly distributed in soil and water, is known to be transmitted through the environment rather than between people. Therefore, it is imperative to establish distinguishable genotyping methods to understand the clinical outcome, disease relapses, and epidemiology. Therefore, in this study, representative band-based genotyping methods were performed using M. intracellualre clinical isolates, and their Hunter-Gaston discriminatory index (HGDI) was 0.947, 0.994, and 1 for variable number tandem repetition (VNTR), VNTR-mycobacterial interspersed repetitive units, pulsed field gel electrophoresis, and repetitive sequence based-PCR, respectively. Although VNTR showed relatively low HGDI, co-infection with other M. intracellualre strains could be determined by loci showing allele diversity from 0 to 0.69. Additionally, genetic distance of clinical isolates from Gyeongnam/Korea, and other regions/countries were visualized by minimum spanning tree (MST) using the globally available VNTR profiles. The results of MST revealed that M. intracellulare isolated from patients in Gyeongnam/Korea had specific VNTR genotypes, which may be evidence of the geographic distribution of M. intracellulare specific genotypes. The comparative results of genotyping techniques and geographical characteristics in this study may provide fundamental information for the epidemiology of M. intracellulare.

Changes in Seroprevalence of Helicobacter pylori Infection over 20 Years in Jinju, Korea, from Newborns to the Elderly.

BACKGROUND: The objective of this study was to examine changes in the prevalence of cytotoxic-associated gene A (CagA) positive Helicobacter pylori infection in Jinju, Korea, over the last 20 years. METHODS: Three cross-sectional analyses were conducted concurrently. A total of 1,305 serum samples were collected from 1994-1995, 2004-2005, and 2014-2015, respectively. The presence of immunoglobulin (Ig) G, IgA, and IgM antibodies against H. pylori CagA protein was examined by western blotting. RESULTS: Overall, seropositivity for anti-CagA IgG antibody was significantly decreased from 63.2% to 42.5% over the last 20 years (P < 0.001). Anti-CagA IgG seropositivities in children and young adults aged 10-29 years decreased from 1994 (60.0%-85.0%) to 2015 (12.5%-28.9%). The age when plateau of increasing IgG seropositivity was reached in each study period shifted from the 15-19 year-old group in 1994-1995 (85.0%) to the 40-49 year-old group in 2014-2015 (82.5%). Overall seropositive rates of anti-CagA IgA and IgM antibodies did not change significantly either over the last 20 years. CONCLUSION: H. pylori infection rate in children and young adults declined over 20 years in Jinju, probably due to improved sanitation, housing, or economy.

Genetic variation in the cag pathogenicity island of Helicobacter pylori strains detected from gastroduodenal patients in Thailand.

There is a lack of evidence of genetic variation in the Helicobacter pylori cag-PAI in Thailand, a region with the low incidence of gastric cancer. To clarify this issue, variation in the H. pylori cag-PAI in strains detected in Thailand was characterized and simultaneously compared with strains isolated from a high-risk population in Korea. The presence of ten gene clusters within cag-PAI (cagA, cagE, cagG, cagH, cagL, cagM, cagT, orf13, virB11, and orf10) and IS605 was characterized in H. pylori strains detected from these two countries. The cagA genotypes and EPIYA motifs were analyzed by DNA sequencing. The overall proportion of the ten cag-PAI genes that were detected ranged between 66 and 79%; additionally, approximately 48% of the strains from Thai patients contained an intact cag-PAI structure, while a significantly higher proportion (80%) of the strains from Korean patients had an intact cag-PAI. A significantly higher proportion of IS605 was detected in strains from Thai patients (55%). Analysis of cagA genotypes and EPIYA motifs revealed a higher frequency of Western-type cagA in Thai patients (87%) relative to Korean patients (8%) who were predominately associated with the East Asian-type cagA (92%). Variations in the Western-type cagA in the Thai population, such as EPIYA-BC patterns and EPIYA-like sequences (EPIYT), were mainly detected as compared with the Korean population (p < 0.05). In summary, H. pylori strains that colonize the Thai population tend to be associated with low virulence due to distinctive cag-PAI variation, which may partially explain the Asian paradox phenomenon in Thailand.

Genetic Polymorphisms of CXCL8 (-251) Are Associated with the Susceptibility of Helicobacter pylori Infection Increased the Risk of Inflammation and Gastric Cancer in Thai Gastroduodenal Patients.

CXC Chemokine Ligand 8 (CXCL8) plays an important role in gastric inflammation and in the progression of gastric cancer induced by Helicobacter pylori (H. pylori) infection. The association of CXCL8, CXC Chemokine Receptor 1 (CXCR1), and CXC Chemokine Receptor 2 (CXCR2) polymorphisms with H. pylori infection and gastric cancer progression needs to be investigated in a population within an enigma area consisting of multiple ethnicities, such as Thailand. To analyze the relative risk of H. pylori infection and gastric cancer among Thai gastroduodenal patients, gene polymorphisms in CXCL8 (promoter region -251) and in CXCR1 and CXCR2 (receptors for CXCL8) were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and allele specific-PCR (AS-PCR). We also determined the presence of cytotoxin-associated gene A (cagA) in Thai patients with H. pylori infection. Correlation between the CXCL8 (-251) polymorphism and CXCL8 gene expression was evaluated by quantitative reverse transcriptase-PCR (qRT-PCR). We found a significant association between the T/A and A/A genotypes of CXCL8 (-251) with H. pylori infection. However, no significant correlation was found between the CXCR1 (+2607) and CXCR2 (+1208) gene polymorphisms with H. pylori infection among Thai gastroduodenal subjects. Within the H. pylori-infected group of Thai gastroduodenal patients, no significant differences in cagA were observed. In addition, the A/A genotype of CXCL8 (-251) significantly correlated with the risk of gastric cancer and correlated with higher CXCL8 gene expression levels in Thai gastroduodenal patients. These results suggest that CXCL8 (-251) polymorphisms are associated with H. pylori infection, an increased risk of stronger inflammatory responses, and gastric cancer in Thai gastroduodenal patients.

Development of bone regeneration strategies using human periosteum-derived osteoblasts and oxygen-releasing microparticles in mandibular osteomyelitis model of miniature pig.

Hypoxia and limited vascularization inhibit bone growth and recovery after surgical debridement to treat osteomyelitis. Similarly, despite significant efforts to create functional tissue-engineered organs, clinical success is often hindered by insufficient oxygen diffusion and poor vascularization. To overcome these shortcomings, we previously used the oxygen carrier perfluorooctane (PFO) to develop PFO emulsion-loaded hollow microparticles (PFO-HPs). PFO-HPs act as a local oxygen source that increase cell viability and maintains the osteogenic differentiation potency of human periosteum-derived cells (hPDCs) under hypoxic conditions. In the present study, we used a miniature pig model of mandibular osteomyelitis to investigate bone regeneration using hPDCs seeded on PFO-HPs (hPDCs/PFO-HP) or hPDCs seeded on phosphate-buffered saline (PBS)-HPs (hPDCs/PBS-HP). Osteomyelitis is characterized by a series of microbial invasion, vascular disruption, bony necrosis, and sequestrum formation due to impaired host defense response. Sequential plain radiography, computed tomography (CT), and 3D reconstructed CT images revealed new bone formation was more advanced in defects that had been implanted with the hPDCs/PFO-HPs than in defects implanted with the hPDCs/PBS-HP. Thus, PFO-HPs are a promising tissue engineering approach to repair challenging bone defects and regenerate structurally organized bone tissue with 3D architecture.

Cell-selectivity of tryptophan and tyrosine in amphiphilic α-helical antimicrobial peptides against drug-resistant bacteria.

The increasing emergence of drug-resistant bacteria creates a requirement for new antibiotics and various types of antibiotic materials such as proteins, peptides, polymers, and chemical compounds. Among these, antimicrobial peptides (AMPs) are considered to be promising antibiotic candidates for clinical treatments. In this study, we have designed a novel series of peptides with repeated sequences of minimum membrane-active motif, 'XWZX' basic sequence (X: lysine or arginine, Z: leucine, tyrosine, valine, or glycine), and an α-helical secondary structure. Some peptides displayed a potent antibacterial activity via membranolytic action and high therapeutic index (toxic dose/minimum inhibitory concentration) in vitro. Furthermore, in vivo experiments using bacterial ear-skin infection models verified that these peptides have the potential to be powerful and safe antibiotics. The present study provides a lead sequence for designing peptide antibiotics against bacterial membranes and information for cell-selectivity of hydrophobic amino acids with aromatic side chains such as Trp and Tyr.

Characterizing antigenic determinants in Helicobacter pylori CagA capable of detecting serum antibodies in children.

Helicobacter pylori can persistently colonize the mucosa of the human stomach, resulting in gastric disorders. Endoscopic biopsy for rapid urease test and histopathologic examination are considered as the most accurate diagnostic methods for H. pylori infection. Serological methods are recommended for children because of invasiveness of the diagnosis mentioned above. Here, the cytotoxin-associated gene A protein (Cag A), as an immunodominant antigen, was subdivided to determine which regions harbor antigenicity for humans. CagA was divided into 17 overlapping fragments of ∼400 bp, which were used for the analysis of antigenic determinants. The partial proteins were subjected to immunoblot analysis using pooled serum samples from children with gastric symptoms. A partial recombinant CagA protein containing epitope regions (683-749 amino acids), which were identified in this study, was produced and used for the detection of anti-CagA antibodies and further investigated its serodiagnostic value for determination of H. pylori infection in children. The serum IgG reactivities from children with gastric symptoms were significantly three times more than that of serum samples from children with non-gastric symptoms (P < 0.005). Moreover, the serum IgG reactivities from children showing strong urease activity of gastric biopsies were significantly higher than those with moderate and weak urease activities (P < 0.05). Hence, the partial CagA is a candidate antigen for diagnosis of H. pylori infection.

Helicobacter pylori Antigens Inducing Early Immune Response in Infants.

To identify the Helicobacter pylori antigens operating during early infection in sera from infected infants using proteomics and immunoblot analysis. Two-dimensional (2D) large and small gel electrophoresis was performed using H. pylori strain 51. We performed 2D immunoglobulin G (IgG), immunoglobulin A (IgA), and immunoglobulin M (IgM) antibody immunoblotting using small gels on sera collected at the Gyeongsang National University Hospital from 4-11-month-old infants confirmed with H. pylori infection by pre-embedding immunoelectron microscopy. Immunoblot spots appearing to represent early infection markers in infant sera were compared to those of the large 2D gel for H. pylori strain 51. Corresponding spots were analyzed by matrix-assisted laser desorption/ionization time of flight-mass spectrometry (MALDI-TOF-MS). The peptide fingerprints obtained were searched in the National Center for Biotechnology Information (NCBI) database. Eight infant patients were confirmed with H. pylori infection based on urease tests, histopathologic examinations, and pre-embedding immunoelectron microscopy. One infant showed a 2D IgM immunoblot pattern that seemed to represent early infection. Immunoblot spots were compared with those from whole-cell extracts of H. pylori strain 51 and 18 spots were excised, digested in gel, and analyzed by MALDI-TOF-MS. Of the 10 peptide fingerprints obtained, the H. pylori proteins flagellin A (FlaA), urease ß subunit (UreB), pyruvate ferredoxin oxidoreductase (POR), and translation elongation factor Ts (EF-Ts) were identified and appeared to be active during the early infection periods. These results might aid identification of serological markers for the serodiagnosis of early H. pylori infection in infants.