BACKGROUND: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) allows rapid and accurate identification of clinical yeast isolates. In-tube formic acid/acetonitrile (FA/ACN) extraction is recommended prior to the analysis with MALDI Biotyper, but the direct on-plate FA extraction is simpler. We compared the Biotyper with the VITEK MS for the identification of various clinically relevant yeast species, focusing on the use of the FA extraction method. METHODS: We analyzed 309 clinical isolates of 42 yeast species (four common Candida species, Cryptococcus neoformans, and 37 uncommon yeast species) using the Biotyper and VITEK MS systems. FA extraction was used initially for all isolates. If ‘no identification' result was obtained following the initial FA extraction, these samples were then retested by using FA (both systems, additive FA) or FA/ACN (Biotyper only, additive FA/ACN) extraction. These results were compared with those obtained by sequence-based identification. RESULTS: Both systems correctly identified all 158 isolates of the four common Candida species after the initial FA extraction. The Biotyper correctly identified 8.7%, 30.4%, and 100% of 23 C. neoformans isolates after performing initial FA, additive FA, and FA/ACN extractions, respectively, while VITEK MS identified all C. neoformans isolates after the initial FA extraction. Both systems had comparable identification rates of 37 uncommon yeast species (128 isolates), following the initial FA (Biotyper, 74.2%; VITEK MS, 73.4%) or additive FA (Biotyper, 82.0%; VITEK MS, 73.4%). CONCLUSIONS: The identification rate of most common and uncommon yeast isolates is comparable between simple FA extraction/Biotyper method and VITEK MS methods, but FA/ACN extraction is necessary for C. neoformans identification by Biotyper.
Candida ; Cryptococcus neoformans ; Mass Spectrometry* ; Methods* ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Yeasts*

Phospholipids are key components of cellular membrane and signaling. Among cellular phospholipids, phosphoinositides, phosphorylated derivatives of phosphatidylinositol are important as a participant in essential metabolic processes in animals. However, due to its low abundance in cells and tissues, it is difficult to identify the composition of phosphoinositides. Recent advances in mass spectrometric techniques, combined with established separation methods, have allowed the rapid and sensitive detection and quantification of a variety of lipid species including phosphoinositides. In this mini review, we briefly introduce progress in profiling of cellular phosphoinositides using mass spectrometry. We also summarize current progress of matrices development for the analysis of cellular phospholipids using matrix-assisted laser desorption/ionization mass spectrometry. The phosphoinositides profiling and phospholipids imaging will help us to understand how they function in a biological system and will provide a powerful tool for elucidating the mechanism of diseases such as diabetes, cancer and neurodegenerative diseases. The investigation of cellular phospholipids including phosphoinositides using electrospray ionization mass spectrometry and matrix-assisted laser desorption/ionization mass spectrometry will suggest new insights on human diseases, and on clinical application through drug development of lipid related diseases.
Animals ; Humans ; Mass Spectrometry/*methods ; Phosphatidylinositols/*metabolism ; Phospholipids/*metabolism ; Spectrometry, Mass, Electrospray Ionization ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

BACKGROUNDEndometriosis is a common gynecological disease. This study aimed to screen proteins that were expressed differently in patients with endometriosis versus normal controls using proteomic techniques, surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS).

METHODSProtein chip SELDI-TOF-MS combines the advantages of microarray and mass spectrometry, and can screen latent markers in sera of patients with endometriosis. Serum samples from patients and normal volunteers were analyzed by SELDI-TOF-MS.

RESULTSAfter comparing the serum protein spectra of 36 patients with 24 normal controls, 24 differently expressed potential biomarkers (P < 0.01) were identified. Using Biomarker Pattern software, we established a tree model of the 60 serum protein spectra. When using the three biomarkers to classify the samples, the sensitivity for diagnosing endometriosis was 91.7%, specificity was 95.8%, and coincidence rate was 93.3%. Then we used serum samples from 12 patients and 8 normal controls to validate the tree model and report the sensitivity for diagnosing endometriosis was 91.7%, specificity was 75%, and coincidence rate was 85%.

CONCLUSIONSSELDI-TOF-MS may be a useful tool in high-risk population screening for endometriosis. The identification and application of the biomarkers need to further study.

Formaldehyde ; Humans ; Microdissection ; Paraffin Embedding ; Proteomics ; methods ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Tissue Fixation

There are many deficiencies in forensic traumatic molecular markers detected by the techniques of traditional immunohistology and molecular biology, because these markers are isolated and obscure of the mechanism of interaction. The imaging mass spectrometry (IMS) is more suitable for the forensic molecular markers using function of screening, analysis and graphical representation. In this paper, the techniques and the latest research in screening and identification of typical molecular markers by IMS based on matrix-assisted laser adsorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) are reviewed. And its application values in forensic injury are discussed.
Biomarkers/analysis* ; Diagnostic Imaging ; Molecular Biology ; Molecular Weight ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods*

Matrix-assisted laser desorption/ionization time-of-flight imaging mass spectrometry (MALDI-TOF-IMS) has been a classical technique for studying proteomics in present and a tool for analyzing the distribution of proteins and small molecules within biological tissue sections. MALDI-TOF-IMS can analyze multiple unknown compounds in biological tissue sections simultaneously through a single measurement which can obtain molecule imaging of the tissue while maintaining the integrity of cellular and molecules in tissue. In recent years, imaging mass spectrometry technique develops relatively quickly in all biomedical domain. This paper based on the relevant data and reviews the present developing level of MALDI-TOF-IMS, the principle of imaging mass spectrometry, methology and the prospect in forensic pathology.
Diagnostic Imaging ; Forensic Sciences/methods* ; Humans ; Male ; Proteins ; Proteomics ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

Biomarkers, Tumor ; metabolism ; Diagnosis, Differential ; Diagnostic Imaging ; Humans ; Mass Spectrometry ; methods ; Neoplasms ; diagnosis ; drug therapy ; metabolism ; Spectrometry, Mass, Electrospray Ionization ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

OBJECTIVETo investigate the clinical value of matrix assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS) in detecting K-ras gene mutation.

METHODSSixty-one paraffin-embeded specimens of colorectal cancer were selected. MALDI-TOF-MS and regular sequencing were used to test the mutation of codon 12 and 13 in K-ras exon 2.

RESULTSOnly 47 specimens could be detected successfully in regular sequencing, while all the specimens were tested successfully in MALDI-TOF-MS. Fourteen specimens had K-ras mutation in regular sequencing (30.0%), while 22 specimens had mutation in MALDI-TOF-MS (36.1%). Six specimens with mutation were found in MALDI-TOF-MS but were wild-type in regular sequencing. Same mutation types from 14 specimens were confirmed by both regular sequencing and MALDI-TOF-MS. MALDI-TOF-MS was able to detect the mutation in 2 specimens that was not identified in regular sequencing.

CONCLUSIONSMALDI-TOF-MS is a feasible approach of K-ras gene mutation testing in colorectal cancer, which is less demanding in terms of specimen quality and is more sensitive as compared to regular sequencing.

With the development of genomics and the accomplishments of human genomic sequencing, polymorphic markers and their analytic approaches are more and more important, and much attention has been paid to the fact that the analysis of single nucleotide polymorphisms utilizing matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF MS) is a high-throughput approach. MALDI-TOF MS can also mini-sequence and genotype short tandem repeat. The approaches to analyzing single nucleotide polymorphisms are primer oligonucleotide base extension, ligase reaction, peptide nucleotide acid, invader assay, and so on.
Genotype ; Humans ; Microsatellite Repeats ; genetics ; Polymorphism, Single Nucleotide ; genetics ; Reproducibility of Results ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; methods

This study was purposed to find new biomarkers and to establish protein finger print model for diagnosis of leukemia. A total of 40 leukemia samples and 37 healthy control samptes were tested by surface enhance laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF- MS). The data of spectra were analyzed by bioinformatics tools like Biomarker Patterns 5.0 and discriminant analysis to establish diagnostic mode1. The results showed that 22 protein features were stably detected by protein fingerprint, The detective model combined with 3 biomarkers (m/z 4650, 8609 and 11660) could differentiate leukemia with sensitivity of 97.5% (39/40) and specificity of 91.9%(34/37). It is concluded that the detective model established by 3 protein features may be a novel method for diagnosis of leukemia.
Biomarkers, Tumor ; analysis ; Humans ; Leukemia ; diagnosis ; Molecular Weight ; Peptide Mapping ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; methods