Time-of-flight
Dotaz
Zobrazit nápovědu
Corynebacterium (C.) durum je součástí rezidentní flóry dutiny ústní. Jeho podíl na etiologii infekčních onemocnění je nejednoznačný. S vyšším počtem imunoalterovaných pacientů je nutné s ním počítat jako s potenciálním oportunním patogenem. Nejčastěji je izolováno ze sputa, bronchoalveolární lavážní tekutiny, ale také z krve, zejména u imunosuprimovaných pacientů s pneumonií. V tom případě je nutné bakterii přesně identifikovat a nález správně interpretovat. Dříve velmi využívaný komerční test pro určení korynebakterií (API Coryne, BioMerieux) nelze použít pro všechna korynebakteria včetně C. durum. Tento druh není obsažen v databázi biotypových čísel. Lze provést porovnání biotypového čísla s údaji v literatuře. K přesnému odlišení od jiných korynebakterií je nutná chemotaxonomická a proteomická analýzy (MALDI-TOF MS), nebo sekvenace genu 16S rRNA. Klíčový je polyfázový přístup využívající poznatky z jednotlivých laboratorních vyšetření.
Corynebaterium (C.) durum is a part of the resident human oral microbiota. Its role in the aetiology of infectious diseases is ambiguous. With the increasing number of immunocompromised patients, it must be considered a potential opportunistic pathogen. It is isolated from the sputum, bronchoalveolar-lavage fluid, as well as blood, especially from immunocompromised patients with pneumonia. In that case, the critical steps involve a correct identification of Corynebacterium to the species level and right interpretation of the findings. The previously widely used commercial test for the identification of Corynebacteria (API Coryne, BioMerieux) is not suitable for all species, including C. durum, as its biotype number is not included in the database. But the obtained result can be compared with the available literature data. Chemotaxonomic and proteomic analysis (matrix-assisted laser desorption/ ionization – time of flight, MALDI-TOF MS) or 16S rRNA sequencing allow for accurate differentiation from the other Corynebacteria species. Nevertheless, these methods are not routinely used in clinical laboratories. A polyphasic approach to the taxonomy based on the data from combined laboratory tests is crucial.
One of the main challenges in analyzing chemical messengers in the brain is the optimization of tissue sampling and preparation protocols. Limiting postmortem time and terminating enzyme activity is critical to identify low-abundance neurotransmitters and neuropeptides. Here, we used a rapid and uniform conductive heat transfer stabilization method that was compared with a conventional fresh freezing protocol. Together with a selective chemical derivatization method and an optimized quantitation approach using deuterated internal standards, we spatially mapped neurotransmitters and their related metabolites by matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) in rat brain tissue sections. Although the heat stabilization did not show differences in the levels of dopamine, norepinephrine, and serotonin, their related metabolites 3,4-dihydroxyphenylacetaldehyde, 3,4-dihydroxyphenylacetic acid, homovanillic acid, 3-methoxy-4-hydroxyphenylacetaldehyde, dihydroxyphenylethyleneglycol, and 5-hydroxyindoleacetic acid were all significantly lower, indicating reduced neurotransmitter postmortem turnover ratios. Heat stabilization enabled detection of an increased number and higher levels of prodynorphin, proenkephalin, and tachykinin-derived bioactive neuropeptides. The low-abundant C-terminal flanking peptide, neuropeptide-γ, and nociceptin remained intact and were exclusively imaged in heat-stabilized brains. Without heat stabilization, degradation fragments of full-length peptides occurred in the fresh frozen tissues. The sample preparation protocols were furthermore tested on rat brains affected by acute anesthesia induced by isoflurane and medetomidine, showing comparable results to non-anesthetized animals on the neurotransmitters level without significant changes. Our data provide evidence for the potential use of heat stabilization prior to MALDI-MSI analyses to improve the examination of the in vivo state of neuronal chemical messengers in brain tissues not impacted by prior acute anesthesia.
- MeSH
- krysa rodu rattus MeSH
- mozek - chemie * fyziologie MeSH
- mozek * metabolismus MeSH
- neurony * metabolismus chemie MeSH
- neurotransmiterové látky * metabolismus analýza MeSH
- potkani Sprague-Dawley MeSH
- spektrometrie hmotnostní - ionizace laserem za účasti matrice * metody MeSH
- vysoká teplota * MeSH
- zmrazování MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Breast milk, as the optimal food for infants and young children, contains all the components necessary for proper growth and development. It is a rich source of both essential nutrients and biologically active factors, making breast milk a unique food with scientifically proven health-promoting properties. Among the entire range of biologically active factors, breast milk microorganisms and prebiotic factors, in the form of breast milk oligosaccharides, occupy an important place. The aim of our research was to determine the occurrence of bacteria with probiotic potential, belonging to the Lactobacillaceae family, in the environment of breast milk and breast milk oligosaccharides. The study included 63 human milk samples from breastfeeding women at various stages of lactation. Microorganism identification based on culture tests and MALDI TOF/MS, macronutrient analysis using the MIRIS human milk analyser, as well as analysis of human milk oligosaccharides using ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry were performed. The results have shown that breast milk from different breastfeeding women is characterized by great diversity in terms of the presence of Lacto-bacillaceae bacteria in its microbiological composition. These bacteria were present in 22.2 % of the tested breast milk samples. Analysis of the human milk oligosaccharide profile revealed a slightly higher content of prebiotic factors in breast milk samples containing Lactobacillaceae, including 2'-fucosyllactose, oligosaccharide occurring in the highest amount in breast milk.
PURPOSE: This study aimed to compare the image quality of the Siemens Biograph mCT40 (photomultiplier-based system - PMT) and the Siemens Vision600 (silicon photomultiplier-based system - SiPM) using a modified NEMA IEC Body phantom (Data Spectrum). METHODS: SiPM-based Vision600 has a smaller crystal size (3.2 × 3.2 mm vs. 4.0 × 4.0 mm in the PMT-based mCT40), resulting in better spatial resolution. Enhanced time-of-flight (TOF) timing and higher sensitivity leads to nearly four times higher effective sensitivity. The standard NEMA IEC Body phantom was modified with a 3D-printed holder to accommodate also Hollow and Micro Hollow Spheres of 15.4 mm, 12.4 mm, 7.9 mm, 6.2 mm, 5.0 mm, and 4.0 mm. Each of the three acquisition sessions per scanner included 18 time points and spanned 5.6 half-lives to assess system performance at varying activity concentrations in the field of view. RESULTS: Recovery curves for both systems were similar when identical post-reconstruction filters were applied. The SiPM-based Vision600 system detected smaller sources at significantly lower activity concentrations, and the variations in standardized uptake value (SUVmax, SUVA50) measurements were generally smaller compared to those of the PMT-based system. The two smallest sources became undetectable below 63 MBq and 16 MBq on the PMT system, versus 20 MBq and 6.5 MBq on the SiPM system. CONCLUSIONS: SiPM technology demonstrated superior performance compared to PMT in detecting small sources in low-activity scenarios and provided more robust quantification results. It is recommended to use averaged SUV metrics, such as SUVA50 or SUVpeak.
Today, MALDI-ToF MS is an established technique to characterize and identify pathogenic bacteria. The technique is increasingly applied by clinical microbiological laboratories that use commercially available complete solutions, including spectra databases covering clinically relevant bacteria. Such databases are validated for clinical, or research applications, but are often less comprehensive concerning highly pathogenic bacteria (HPB). To improve MALDI-ToF MS diagnostics of HPB we initiated a program to develop protocols for reliable and MALDI-compatible microbial inactivation and to acquire mass spectra thereof many years ago. As a result of this project, databases covering HPB, closely related bacteria, and bacteria of clinical relevance have been made publicly available on platforms such as ZENODO. This publication in detail describes the most recent version of this database. The dataset contains a total of 11,055 spectra from altogether 1,601 microbial strains and 264 species and is primarily intended to improve the diagnosis of HPB. We hope that our MALDI-ToF MS data may also be a valuable resource for developing machine learning-based bacterial identification and classification methods.
BACKGROUND: Multiple myeloma (MM) represents the second most common hematological malignancy characterized by the infiltration of the bone marrow by plasma cells that produce monoclonal immunoglobulin. While the quality and length of life of MM patients have significantly increased, MM remains a hard-to-treat disease; almost all patients relapse. As MM is highly heterogenous, patients relapse at different times. It is currently not possible to predict when relapse will occur; numerous studies investigating the dysregulation of non-coding RNA molecules in cancer suggest that microRNAs could be good markers of relapse. RESULTS: Using small RNA sequencing, we profiled microRNA expression in peripheral blood in three groups of MM patients who relapsed at different intervals. In total, 24 microRNAs were significantly dysregulated among analyzed subgroups. Independent validation by RT-qPCR confirmed changed levels of miR-598-3p in MM patients with different times to relapse. At the same time, differences in the mass spectra between groups were identified using matrix-assisted laser desorption/ionization time of flight mass spectrometry. All results were analyzed by machine learning. CONCLUSION: Mass spectrometry coupled with machine learning shows potential as a reliable, rapid, and cost-effective preliminary screening technique to supplement current diagnostics.
- Publikační typ
- časopisecké články MeSH
Candida haemulonii complex (Candida haemulonii [I], Candida duobushaemulonii [II], and Candida haemulonii var. vulnera [III]) has become relevant in recent times, not so much because of a high incidence in human clinical sample cultures but because of its remarkable antifungal resistance. The objective of this study was to evaluate several methods for the identification of this uncommon species of Candida. Ten isolates of C. haemulonii were identified by biochemical and proteomic methods, and their antifungal susceptibility testing was performed by both commercial and reference methods. MALDI-TOF MS (Vitek MS and Vitek MS PRIME) and Vitek2 correctly identified these genera but API method did not. There was a good correlation between the commercial methods and the reference methods for the AST. In conclusion Vitek MS, Vitek MS PRIME, and Vitek2 systems, but not API32C, are reliable for identification of C. haemulonii complex. Furthermore, MALDI-TOF MS systems could identify to the subspecies level. Commercial methods for antifungal susceptibility testing are valid for the study of this species and confirm amphotericin B and to azole resistance.
Spektrum cievnych anomálií s rôznym biologickým správaním je veľmi široké. Vaskulárne anomálie sa rozdeľujú na vaskulárne malformácie a vaskulárne nádory – hemangiómy. Hoci mnohé z nich vyzerajú podobne, ich klinická manifestácia je rozmanitá – od nezávažného samolimitujúceho priebehu po život ohrozujúce komplikácie vyžadujúce intenzívny multidisciplinárny terapeutický prístup. Nezriedka sa aj v odbornej praxi všetky cievne anomálie nesprávne nazývajú hemangiómy. Je veľmi dôležité správne klasifikovať a pomenovať cievnu anomáliu, aby sme mohli zvoliť správnu liečbu a zabrániť vzniku závažných komplikácií. Z vaskulárnych nádorov sa u detí najčastejšie vyskytuje infantilný hemangióm (IH). Je to lézia s úplne typickým biologickým správaním a na jej odlíšenie od iných cievnych anomálií zvyčajne stačí dobre odobratá anamnéza. Iba malá časť IH predstavuje pre dieťa riziko a vyžaduje systémovú alebo kombinovanú multimodálnu liečbu. Vaskulárne malformácie predstavujú heterogénnu skupinu zvyčajne vývinových odchýlok cievneho systému a môžu postihovať ktorýkoľvek typ ciev. Často ide o zmiešané cievne lézie. Symptomatické vaskulárne malformácie sú u detí zriedkavé a mnohokrát predstavujú pre lekárov diagnosticko-terapeutickú výzvu. Prinášame kazuistiku nesyndrómového pacienta, u ktorého sa vyskytli dve zriedkavé symptomatické cievne anomálie vyžadujúce multiodborovú starostlivosť. Korešpondenčná autorka: MUDr. Michaela Murgašová Klinika detí a dorastu JLF UK a UNM Kollárova 2 036 01 Martin Slovenská republika murgasovam@zoznam.sk
The spectrum of vascular anomalies with different biological behavior is very wide. They are divided into vascular malformations and vascular tumors – hemangiomas. Although many of them look similar, their clinical manifestation is different – from a mild self-limiting course to life-threatening complications requiring an intensive multidisciplinary therapeutic approach. Frequently, even in professional practice, all vascular anomalies are incorrectly called hemangiomas. It is very important to classify and name the vascular anomaly correctly so that we can choose the right treatment and prevent serious complications. Infantile hemangioma (IH) is the most common vascular tumor in children. It is a lesion with a completely typical biological behavior and a well-taken history is usually sufficient to distinguish it from other vascular anomalies. Only a small part of IH represents a risk to the child and requires systemic or combined multimodal treatment. Vascular malformations represent a heterogeneous group of usually developmental abnormalities of the vascular system and can affect any type of vessels. These are often mixed vascular lesions. Symptomatic vascular malformations are rare in children and often are diagnostic and therapeutic challenge for doctors. We present a case report of a non-syndromic patient with two rare symptomatic vascular anomalies requiring multidisciplinary care.
- MeSH
- cévní malformace diagnóza klasifikace MeSH
- dítě MeSH
- endovaskulární výkony klasifikace metody MeSH
- kapilární hemangiom * diagnostické zobrazování diagnóza MeSH
- karotido-kavernózní píštěl * diagnostické zobrazování diagnóza klasifikace komplikace MeSH
- kojenec MeSH
- lidé MeSH
- magnetická rezonanční angiografie metody MeSH
- metoprolol farmakologie terapeutické užití MeSH
- novorozenec MeSH
- prednison farmakologie terapeutické užití MeSH
- Check Tag
- dítě MeSH
- kojenec MeSH
- lidé MeSH
- mužské pohlaví MeSH
- novorozenec MeSH
- Publikační typ
- kazuistiky MeSH
Spinal cord injury (SCI) often leads to central neuropathic pain, a condition associated with significant morbidity and is challenging in terms of the clinical management. Despite extensive efforts, identifying effective biomarkers for neuropathic pain remains elusive. Here we propose a novel approach combining matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) with artificial neural networks (ANNs) to discriminate between mass spectral profiles associated with chronic neuropathic pain induced by SCI in female mice. Functional evaluations revealed persistent chronic neuropathic pain following mild SCI as well as minor locomotor disruptions, confirming the value of collecting serum samples. Mass spectra analysis revealed distinct profiles between chronic SCI and sham controls. On applying ANNs, 100% success was achieved in distinguishing between the two groups through the intensities of m/z peaks. Additionally, the ANNs also successfully discriminated between chronic and acute SCI phases. When reflexive pain response data was integrated with mass spectra, there was no improvement in the classification. These findings offer insights into neuropathic pain pathophysiology and underscore the potential of MALDI-TOF MS coupled with ANNs as a diagnostic tool for chronic neuropathic pain, potentially guiding attempts to discover biomarkers and develop treatments.
- MeSH
- biologické markery krev MeSH
- chronická bolest krev diagnóza etiologie MeSH
- myši inbrední C57BL MeSH
- myši MeSH
- neuralgie * krev diagnóza etiologie MeSH
- neuronové sítě * MeSH
- poranění míchy * komplikace krev MeSH
- spektrometrie hmotnostní - ionizace laserem za účasti matrice * metody MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The MBT Pathfinder is an automated colony-picking robot designed for efficient sample preparation in matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. This article presents results from three key experiments evaluating the instrument's performance in conjunction with MALDI Biotyper instrument. The method comparison experiment assessed its clinical performance, demonstrating comparable results with gram-positive, gram-negative, and anaerobic bacteria (scores larger than 2.00) and superior performance over simple direct yeast transfer (score: 1.80) when compared to samples prepared manually. The repeatability experiment confirmed consistent performance over multiple days and labs (average log score: 2.12, std. deviation: 0.59). The challenge panel experiment showcased its consistent and accurate performance across various samples and settings, yielding average scores between 1.76 and 2.19. These findings underline the MBT Pathfinder as a reliable and efficient tool for MALDI-TOF mass spectrometry sample preparation in clinical and research applications.
- MeSH
- Bacteria * klasifikace izolace a purifikace MeSH
- laboratorní automatizace * metody MeSH
- lidé MeSH
- odběr biologického vzorku metody MeSH
- reprodukovatelnost výsledků MeSH
- robotika * MeSH
- spektrometrie hmotnostní - ionizace laserem za účasti matrice * metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
