Protein extraction step is particularly important for identification of mycobacterial isolates by MALDI-TOF mass spectrometry (MS) because of its thick and solid cell wall. This study compared the ...performance of MALDI-TOF MS for identification of mycobacterial clinical isolates cultured in liquid media between heating-based protocol and non-heating protocol.
Clinical mycobacterial isolates cultured in liquid media were prospectively analyzed. Reference identification was real-time PCR and restriction fragment length polymorphism. The specimens prepared by heating protocol and non-heating protocol were tested using MALDI Biotyper (Bruker Daltonics, Bremen, Germany) and Vitek MS (bioMérieux, Marcy l'Etoile, France), respectively.
Among the 206 clinical specimens prepared by heating method, identification rates were 90.3% and 60.7% in MALDI Biotyper and Vitek MS, respectively. Identification accuracy of MALDI Biotyper and Vitek MS was 100% for the isolates of Mycobacterium tuberculosis complex (MTBC), Mycobacterium avium, Mycobacterium intracellulare, Mycobacterium abscessus and Mycobacterium fortuitum. Among the 121 clinical specimens prepared by non-heating method, identification rate for MALDI Biotyper and Vitek MS were 61.2% and 69.4%, respectively. Identification accuracy of MALDI Biotyper/Vitek MS were 92.9%/94.1% for MTBC, 92.9%/100% for M. avium, 90%/100% for M. intracellulare, 100%/100% for M. abscessus and 100%/100% for M. fortuitum.
The performance of MALDI-TOF MS for identification of mycobacterial clinical isolates is affected by protein extraction protocol. For best performance, protein extraction protocol should be chosen considering the MALDI-TOF MS system. In the present study, heating protocol with MALDI Biotyper system showed reliable identification results for mycobacterial clinical isolates.
•Protein extraction impacts greatly the performance of MALDI-TOF MS for identification of mycobacterial isolates.•Protein extraction protocol should be chosen considering the characteristics of MALDI-TOF system.•Heating-based protein extraction showed 90% accuracy for mycobacterial clinical isolates in Bruker MALDI-TOF system.
Idiopathic pulmonary fibrosis (IPF) is caused by alterations in expression of proteins involved in multiple pathways, including matrix deposition, inflammation, injury, and repair.
To understand the ...pathogenic changes in lung protein expression in IPF and to evaluate apolipoprotein (Apo) A-I as a candidate therapeutic molecule.
Two-dimensional electrophoresis was adopted for differential display proteomics. Reverse-transcriptase polymerase chain reaction, Western blotting, immunohistochemical staining, and ELISA were performed for identification and quantitative measurement of Apo A-I in bronchoalveolar lavage fluids from subjects with IPF and experimental bleomycin-induced mice.
Sixteen protein spots showed differences in relative intensity between IPF (n = 14) and healthy control subjects (n = 8). Nano liquid chromatography-tandem mass spectrometry (LC-MS/MS) revealed increase of haptoglobulin and decrease of alpha(1)-antitrypsin, alpha(1)-antichymotrypsin, macrophage capping protein, angiotensinogen, hemoglobin chain B, Apo A-I, clusterin, protein disulfide isomerase A3, immunoglobulin, and complement C4A in IPF compared with normal control subjects (P = 0.006-0.044). Apo A-I concentrations were lower in bronchoalveolar lavage fluids from subjects with IPF (n = 28) than in normal control subjects (n = 18; P < 0.01). In bleomycin-treated mice, Apo A-I protein in BALF was lower than that in sham-treated control animals. Immunohistochemical analysis showed positive staining on intraalveolar macrophages and epithelial cells of the lungs. Intranasal treatment with Apo A-I protein reduced the bleomycin-induced increases in number of inflammatory cells and collagen deposition in sham-treated mice in a dose-dependent manner.
Alterations of several inflammatory and antiinflammatory proteins in the lungs may be related to the pathogenesis of IPF, and local treatment with Apo A-I is very effective against the development of experimental lung injury and fibrosis.
Si3N4-Cfiber composites using waste-Si sludge were fabricated by hot pressing at 1850NBDGC for 2 h with and without the addition of carbon powder. The composites were composed of small amounts of ...*b-Si3N4, O'SiAlON, SiC and Y2SiO5 regardless of carbon powder addition. In the composite without the addition of carbon powder, most of the carbon fibers were graphitized with fine particles. Furthermore, many cavities were observed in the interior regions of C-fibers as well as at the interfaces of Si3N4/Cfiber caused by the decomposition of them. However, in the composite with 3 wt.%C powder added, the core regions of C-fibers still existed in an amorphous. The average size of a matrix grain in the composite using 3 wt.%C powder was slightly finer than that of composite fabricated without using carbon powder, which was caused by the existence of nanometer-sized SiC particles.
Aspirin-intolerant asthma (AIA) is characterized by severe asthmatic attack after ingestion of aspirin and/or non-steroidal anti-inflammatory drugs. In this study, we investigated the relationship ...between Prostaglandin E2 receptor (PTGER) gene family polymorphisms and AIA in 243 AIA patients and 919 aspirin- tolerant asthma (ATA) controls of Korean ethnicity in two separate study cohorts. After genotyping 120 SNPs of the PTGER gene family for the 1st cohort study, four SNPs in PTGER1, ten in PTGER3, six in PTGER3, and a haplotype of PTGER2 showed association signals with decreased or increased risk of AIA. Among the positively associated SNPs, one in PTGER1 and four in PTGER3 were analyzed in the 2nd cohort study. The results show that rs7543182 and rs959 in PTGER3 retained their effect, although no statistical significance was retained in the 2nd cohort study. Our findings provide further evidence that polymorphisms in PTGER3 might play a significant role in aspirin hypersensitivity among Korean asthmatics. BMB reports 2010; 43(6): 445-449
While the coronavirus disease 2019 pandemic is ongoing, monkeypox has been rapidly spreading in non-endemic countries since May 2022. Accurate and rapid laboratory tests are essential for identifying ...and controlling monkeypox. Korean Society for Laboratory Medicine and the Korea Disease Prevention and Control Agency have proposed guidelines for diagnosing monkeypox in clinical laboratories in Korea. These guidelines cover the type of tests, selection of specimens, collection of specimens, diagnostic methods, interpretation of test results, and biosafety. Molecular tests are recommended as confirmatory tests. Skin lesion specimens are recommended for testing in the symptomatic stage, and the collection of both blood and oropharyngeal swabs is recommended in the presymptomatic or prodromal stage.
Abiotrophia defectiva
is a rare pathogen of infective endocarditis (IE) but is frequently involved in embolic complication and valvular dysfunction. IE caused by
A. defectiva
in children is poorly ...studied. This study reports four cases of
A. defectiva
IE in children and reviews previously reported five pediatric cases of
A. defectiva
IE. Most of the patients presented with a subacute course, with prolonged fever or atypical symptoms. Eight patients had embolic complications at presentation. All nine children were treated with combination antimicrobial therapy and six of them received surgical intervention. All patients recovered well without relapse.
A. defectiva
should be considered in children with infective endocarditis, especially in those with atypical presentations. As complications are frequent and more than half of the patients need surgical treatment, prompt diagnosis along with appropriate treatment is necessary.
The myosin light chain kinase (MYLK) gene encodes both smooth muscle and nonmuscle cell isoforms. Recently, polymorphisms in MYLK have been reported to be associated with several diseases. To examine ...the genetic effects of polymorphisms on the risk of asthma and related phenotypes, we scrutinized MYLK by re-sequencing/genotyping and statistical analysis in Korean population (n = 1,015). Seventeen common polymorphisms located in or near exons, having pairwise r² values less than 0.25, were genotyped. Our statistical analysis did not replicate the associations with the risk of asthma and log-transformed total IgE levels observed among African descendant populations. However, two SNPs in intron 16 (+89872C greater than G and +92263T greater than C), which were in tight LD (|D'| = 0.99), revealed significant association with log-transformed blood eosinophil level even after correction multiple testing (P = 0.002/P∨corr = 0.01 and P = 0.002/P∨corr = 0.01, respectively). The log-transformed blood eosinophil levels were higher in individuals bearing the minor alleles for +89872C greater than G and +92263T greater than C, than in those bearing other allele. In additional subgroup analysis, the genetic effects of both SNPs were much more apparent among asthmatic patients and atopic asthma patients. Among atopic asthma patients, the log-transformed blood eosinophil levels were proportionally increased by gene-dose dependent manner of in both +89872C greater than G and +92263T greater than C (P = 0.0002 and P = 0.00007, respectively). These findings suggest that MYLK polymorphisms might be among the genetic factors underlying differential increases of blood eosinophil levels among asthmatic patients. Further biological and/or functional studies are needed to confirm our results.
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