Determination of the cause of selected canine urolith formation by advanced analytical methods.

OBJECTIVE: The goal of this study was to determine the cause of selected canine urolith formation using less conventional but more advanced analytical methods. METHODS: A routine laboratory specialising in urinary calculi analysis noticed a special type of core zone in some canine uroliths, which was typically made up of cylindrical holes. Of 4028 canine samples analysed, non-absorbable suture material was detected in 9 (0·22%) cases. A hollow cylindrical central area was found in a further 13 (0·32%) samples. X-ray microtomography (µCT) was utilised in order to reveal the channel structure inside this urolith sample. Matrix-assisted laser desorption-ionisation - time of flight mass spectrometry was used in order to assess the cause of this urinary stone formation. RESULTS: The diameter of the channel structure corresponded with the diameter of the previously utilised suture material and indicated that this urolith was formed around residual suture material. Further confirmation was provided by the comparative matrix-assisted laser desorption-ionisation - time of flight mass spectrometry chemical analysis. This channel structure is formed by a surgical thread that serves as a base for the urolith growth. CLINICAL SIGNIFICANCE: Results of this study confirm the causative role of absorbable suture material in the pathogenesis of hollow channel structures in some canine compound uroliths.

Prey-race drives differentiation of biotypes in ant-eating spiders.

1. Disruptive natural selection resulting from specialization on different hosts is recognized as one of the most important driving forces in the diversification of herbivores and parasites. It has been proposed that a similar mechanism could apply to carnivorous predators too, although the evidence is still lacking. 2. Here, we show that the differentiation of biotypes of specialized ant-eating spiders of the genus Zodarion has probably been induced by prey-shifting. We focused on two forms of one species Z. styliferum from the Iberian Peninsula that presumably represent ecological races. We conducted geographic, ecological, venom-oriented, reproductive and genetic divergence analysis among multiple populations collected at a number of sites across Portugal and Madeira. 3. Geographic analysis revealed that the two forms occur in mosaic sympatry. Each form was found to associate in nature with a different ant species in a different habitat. Specifically, the styliferum form hunted predominantly Messor ants, and the extraneum form hunted mainly Camponotus ants. Laboratory experiments revealed that the two forms exhibit a significant preference for attacking focal ants, demonstrating higher paralysis efficiency, and also show different venom composition. Cross-mating of the two forms was significantly less likely than between pairs of the same form, suggesting moderate assortative mating. Phylogenetic analyses indicate low genetic differentiation of the two forms and parallel-repeated evolution of biotypes. 4. Adaptive prey-shifting correlated with habitat preference are at present the most valid explanations for biotype formation in Zodarion. The speciation of ant-eating Zodarion spiders thus appears to follow a scenario similar to that of host-shifting in parasites and herbivores.

[Comparative plasma proteomic analysis of patients with multiple myeloma treated with bortezomib-based regimens]. / Srovnávací proteomická analýza krevní plazmy pacientu s mnohocetným myelomem lécených rezimy s bortezomibem.

BACKGROUNDS: Recently, the term biomarker has become, especially in connection with the term clinical proteomics, one of the most frequent terms in the field of biomedical research. The aim of this work was to select an appropriate pre-fractionation method of blood plasma prior to a subsequent proteomic analysis of low-abundant fraction of proteins by two dimensional gel electrophoresis (2-DE) and mass spectrometry to improve the resolution of 2-DE maps and protein identification. MATERIALS AND METHODS: First, we compared two prefractionation methods (MARS versus ProteoMiner) preceding 2-DE analysis using 10 blood plasma samples. Based on the results of the comparative experiments, low-abundant plasma protein fractions from 18 multiple myeloma patients treated with bortezomib were analyzed. Patients were divided into two groups: a group resistant to chemotherapy (9 patients--disease progression, stable disease) and a group with positive clinical response (9 patients--complete and partial remission). RESULTS AND CONCLUSION: Samples prefractioned by ProteoMiner method yielded 2-DE maps with a significantly increased number of detected protein spots, as compared to immunodepletion method MARS (Multiple Affinity Removal System). Between groups of chemoresistant and sensitive patients treated with bortezomib, 15 differently intense spots were revealed by image analysis. These spots were found to correspond to 10 proteins, as confirmed by mass spectrometry. Seven proteins had significantly lower protein level in the group of chemosensitive patients (serum amyloid P, fibrinogen--gamma chain, retinol-binding protein 4, complement factor C4-A, apolipoprotein E, carboxypeptidase N and complement factor H-related protein 1) and 3 proteins showed significantly higher levels of protein (or were only detected) in the group of chemosensitive patients (serum paraoxonase 1, alpha-1-antitrypsin and complement factor B).

[Proteomic analysis of cancer cells]. / Proteomická analýza nádorových bunek.

The rapid development of analytical instrumentation and methodical approaches in the course of the last two decades has significantly extended the possibilities of studying proteins in living systems. Proteomic analysis provides ever deeper insights into the molecular nature of biological processes in terms of qualitative and quantitative changes in protein composition in connection with the physiological and pathological states of the organism. Thus, proteomic analysis contributes to a better understanding of these processes and becomes a tool for the development and validation of diagnostic and therapeutic approaches. Thanks to recent achievements, the attention of cancer specialists is more and more focused on human proteome research. In this brief review we explain the principles of widely used proteomic techniques (gel electrophoresis, liquid chromatography, mass spectrometry analysis, protein array technologies) and show examples of their application in oncology, namely hematooncological diseases.

Proteomic profiling of human embryonic stem cell-derived microvesicles reveals a risk of transfer of proteins of bovine and mouse origin.

BACKGROUND AIMS: Microvesicles (MV) shed from the plasma membrane of eukaryotic cells, including human embryonic stem cells (hESC), contain proteins, lipids and RNA and serve as mediators of cell-to-cell communication. However, they may also contain immunogenic membrane domains and infectious particles acquired from xenogenic components of the culture milieu. Therefore, MV represent a potential risk for clinical application of cell therapy. METHODS: We tested the ability of hESC and their most commonly used feeder cells, mouse embryonic fibroblasts (MEF), to produce MV. We found that hESC are potent producers of MV, whereas mitotically inactivated MEF do not produce any detectable MV. We therefore employed a combined proteomic approach to identify the molecules that constitute the major components of MV from hESC maintained in a standard culture setting with xenogenic feeder cells. RESULTS: In purified MV fractions, we identified a total of 22 proteins, including five unique protein species that are known to be highly expressed in invasive cancers and participate in cellular activation, metastasis and inhibition of apoptosis. Moreover, we found that hESC-derived MV contained the immunogenic agents apolipoprotein and transferrin, a source of Neu5Gc, as well as mouse retroviral Gag protein. CONCLUSIONS: These findings indicate that MV represent a mechanism by which hESC communicate; however, they also serve as potential carriers of immunogenic and pathogenic compounds acquired from environment. Our results highlight a potential danger regarding the use of hESC that have previously been exposed to animal proteins and cells.

Simultaneous determination of molybdenum(VI) and tungsten(VI) and its application in elemental analysis of polyoxometalates.

Spectrophotometric determination of molybdenum(VI) and tungsten(VI) with application of Artificial Neural Networks is proposed and it was applied for elemental analysis of solid polyoxometalates. Better results in comparison with previously those achieved by previous published method were demonstrated. MALDI-TOF Mass Spectrometry was tested for possible determination of molecular weight of polyoxometalates utilizing different matrices. Phenomena observed during desorption-ionisation processes are discussed. LDI-TOF MS was found to be suitable for the determination of Mo:W ratio in polyoxometalates as a rapid screening method to follow synthetic procedure.

Advantages of derivatization by osmium tetroxide and 2,2'-bipyridine for matrix-assisted laser desorption/ionization post-source decay fragment ion analysis of peptides.

Matrix-assisted laser desorption/ionization--post-source decay (MALDI-PSD) fragment ion analysis is frequently used for peptide sequence determination. PSD fragmentation is often changed or improved in terms of, e.g., sequence coverage, after derivatization. In this work, the influence of modification by an osmium tetroxide-bipyridine reagent (Os,bipy) on the MALDI-PSD behaviour of peptides is studied. The reagent modifies peptides specifically at tryptophan residues and oxidizes methionine to methionine sulfone and cysteine to cysteic acid. As a result the masses of some of the fragments are specifically shifted in case of peptides containing a methionine by +32 Da and, in cases of peptides containing a cysteine residue, by +48 Da. In addition, due to the change in protonation properties of a peptide after oxidation, fragments containing cysteic acid are in most cases totally suppressed. This effect significantly facilitates peptide sequence determination. Improvement of MALDI-TOFMS and PSD analysis after the reaction with Os,bipy is demonstrated for examples involving derivatives of humanin, a novel neuroprotective peptide.