Evaluation of imaging parameters of ultrasound scanners : baseline for future testing

Background: Regular quality control is required in Poland only for those methods of medical imaging which involve the use of ionizing radiation but not for ultrasonography. It is known that the quality of ultrasound images may be affected by the wearing down or malfunctioning of equipment. Material/Methods: An evaluation of image quality was carried out for 22 ultrasound scanners equipped with 46 transducers. The CIRS Phantom model 040GSE was used. A set of tests was established which could be carried out with the phantom, including: depth of penetration, dead zone, distance measurement accuracy, resolution, uniformity, and visibility of structures. Results: While the dead zone was 0 mm for 89% of transducers, it was 3 mm for the oldest transducer. The distances measured agreed with the actual distances by 1 mm or less in most cases, with the largest difference of 2.6 mm. The resolution in the axial direction for linear transducers did not exceed 1 mm, but it reached even 5 mm for some of the convex and sector transducers, especially at higher depths and in the lateral direction. For 29% of transducers, some distortions of anechoic structures were observed. Artifacts were detected for several transducers. Conclusions: The results will serve as a baseline for future testing. Several cases of suboptimal image quality were identified along with differences in performance between similar transducers. The results could be used to decide on the applicability of a given scanner or transducer for a particular kind of examination

Visualization of gold and platinum nanoparticles interacting with Salmonella Enteritidis and Listeria monocytogenes

Ewa Sawosz1, André Chwalibog2, Jacek Szeliga3, Filip Sawosz2, Marta Grodzik1, Marlena Rupiewicz1, Tomasz Niemiec1, Katarzyna Kacprzyk11Division of Biotechnology and Biochemistry of Nutrition, Warsaw University of Life Sciences, Warsaw, Poland; 2Department of Basic Animal and Veterinary Sciences, University of Copenhagen, Copenhagen, Denmark; 3Division of Microbiology of Analytical Centre, Warsaw University of Life Sciences, Warsaw, PolandPurpose: Rapid development of nanotechnology has recently brought significant attention to the extraordinary biological features of nanomaterials. The objective of the present ­investigation was to evaluate morphological characteristics of the assembles of gold and platinum nanoparticles (nano-Au and nano-Pt respectively), with Salmonella Enteritidis (Gram-negative) and Listeria monocytogenes (Gram-positive), to reveal possibilities of constructing bacteria-nanoparticle vehicles.Methods: Hydrocolloids of nano-Au or nano-Pt were added to two bacteria suspensions in the following order: nano-Au + Salmonella Enteritidis; nano-Au + Listeria monocytogenes; nano-Pt + Salmonella Enteritidis; nano-Pt + Listeria monocytogenes. Samples were inspected by transmission electron microscope.Results: Visualization of morphological interaction between nano-Au and Salmonella Enteritidis and Listeria monocytogenes, showed that nano-Au were aggregated within flagella or biofilm network and did not penetrate the bacterial cell. The analysis of morphological effects of interaction of nano-Pt with bacteria revealed that nano-Pt entered cells of Listeria monocytogenes and were removed from the cells. In the case of Salmonella Enteritidis, nano-Pt were seen inside bacteria cells, probably bound to DNA and partly left bacterial cells. After washing and centrifugation, some of the nano-Pt-DNA complexes were observed within Salmonella Enteritidis.Conclusion: The results indicate that the bacteria could be used as a vehicle to deliver nano-Pt to specific points in the body.Keywords: morphology, nanoparticles, gold, platinum, bacteri

Fine-tuning of the stability of β-strands by Y181 in perfringolysin O directs the prepore to pore transition

Perfringolysin O (PFO) is a toxic protein that forms β-barrel transmembrane pores upon binding to cholesterol-containing membranes. The formation of lytic pores requires conformational changes in PFO that lead to the conversion of water-soluble monomers into membrane-bound oligomers. Although the general outline of stepwise pore formation has been established, the underlying mechanistic details await clarification. To extend our understanding of the molecular mechanisms that control the pore formation, we compared the hydrogen-deuterium exchange patterns of PFO with its derivatives bearing mutations in the D3 domain. In the case of two of these mutations F318A, Y181A, known from previous work to lead to a decreased lytic activity, global destabilization of all protein domains was observed in their water-soluble forms. This was accompanied by local changes in D3 β-sheet, including unexpected stabilization of functionally important β1 strand in Y181A. In case of the double mutation (F318A/Y181A) that completely abolished the lytic activity, several local changes were retained, but the global destabilization effects of single mutations were reverted and hydrogen-deuterium exchange (HDX) pattern returned to PFO level. Strong structural perturbations were not observed in case of remaining variants in which other residues of the hydrophobic core of D3 domain were substituted by alanine. Our results indicate the existence in PFO of a well-tuned H-bonding network that maintains the stability of the D3 β-strands at appropriate level at each transformation step. F318 and Y181 moieties participate in this network and their role extends beyond their direct intermolecular interaction during oligomerization that was identified previously

Wybrane uwarunkowania osobowościowe pacjentów z reumatoidalnym zapaleniem stawów

INTRODUCTION: The aim of the study was to identify selected personality determinants in patients with rheumatoid arthritis. MATERIAL AND METHODS: Pilot clinical studies were performed in 108 patients with rheumatoid arthritis. The majority of the study sample (69%) was women. The study was conducted from March to April 2015 in the rheumatology departments of Silesian hospitals. The selected personality traits were measured using two psychometric tools: the A-Framingham Scale in Juczyński's Polish adaptation and the NEO-FFI Personality Inventory adapted to Polish conditions by Zawadzki et al. The study also used sociodemographic metrics. RESULTS: The study results showed an increased intensification of the type A behaviour pattern in the study group. A positive relationship was observed between the A pattern and neuroticism. Furthermore, statistically significant positive correlations were reported between extraversion and openness to experience, and between conscientiousness and agreeableness. Moreover, statistically significant negative relationships were found between neuroticism and extraversion and agreeableness. There was a significant correlation between sociodemographic variables such as gender, marital status, education, age, and personality traits like extraversion, conscientiousness and neuroticism, agreeableness and openness to experience. CONCLUSIONS: The personality factor is important in patients with RA. Continuing clinical trials with regard to personality determinants in patients with RA and learning about these conditions may contribute to deeper understanding of the etiopathogenesis, the course of the disease and more effective treatment of this condition.WSTĘP: Celem pracy było określenie wybranych uwarunkowań osobowościowych pacjentów z rozpoznanym reumatoidalnym zapaleniem stawów. MATERIAŁ I METODY: Badania kliniczne o charakterze pilotażowym przeprowadzono wśród 108 pacjentów z rozpoznanym reumatoidalnym zapaleniem stawów. Większość badanej próby (69%) stanowiły kobiety. Badania prowadzono od marca do kwietnia 2015 r. na oddziałach reumatologicznych szpitali województwa śląskiego. Wybrane cechy osobowościowe zmierzono za pomocą dwóch narzędzi psychometrycznych: Skali Typu A-Framingham w polskiej adaptacji Juczyńskiego oraz Inwentarza Osobowości NEO-FFI, zaadaptowanego do polskich warunków przez Zawadzkiego i wsp. W badaniu wykorzystano także metryczkę socjodemograficzną. WYNIKI: Wyniki badań wykazały podwyższone nasilenie wzoru zachowania A w badanej grupie. Stwierdzono dodatnią zależność między wzorem zachowania A a neurotycznością. Zaobserwowano również istotne statystycznie dodatnie związki między ekstrawersją a otwartością na doświadczenie oraz między sumiennością i ugodowością. Wykazano także, że zachodzą istotne statystycznie ujemne związki między neurotycznością a ekstrawersją oraz ugodowością. Zaobserwowano istotną korelację pomiędzy zmiennymi socjodemograficznymi, takimi jak: płeć, stan cywilny, wykształcenie, wiek, a cechami osobowościowymi, jak: ekstrawersja, sumienność i neurotyczność, ugodowość i otwartość na doświadczenie. WNIOSKI: Czynnik osobowościowy ma istotne znaczenie u pacjentów z rozpoznanym RZS. Kontynuacja badań klinicznych w zakresie uwarunkowań osobowościowych chorych na RZS oraz poznanie tych uwarunkowań mogą przyczynić się do głębszego zrozumienia etiopatogenezy, przebiegu choroby oraz wpłynąć na efektywniejsze leczenie tego schorzenia

Evaluation of the quality of mammographic screening examinations performed in the Mazovian Province in 2007-2009

Background: There is a significant risk of radiation-induced carcinogenesis associated with x-ray mammography. Therefore, the dose received by a woman during mammography should be as low as possible, with an optimal quality of the image. The purpose of this study was to assess changes in the quality of mammographic examinations within three consecutive years of the screening program in the Mazovian Province. Material/Methods: The material for this study consisted of protocols from 114 mammography facilities, developed by physicists from the Mazovian Coordinating Centre in 2007-2009. According to the method published by Dance, individual doses (data from 2007 and 2008) and the value of the absorbed dose in a routine exposure of a standard PMMA phantom with a thickness of 4.5 cm were calculated. Moreover, optical densities of the phantom image (data from the years 2007 to 2009) were measured. Results: The weighted average value of the calculated individual doses in 2008 was lower by 15%, as compared to the value from 2007. Reduction of individual doses is also reflected in the reduced phantom dose in routine exposures performed in consecutive years. In 2007, 2008, and 2009, the phantom dose in routine exposures did not exceed 2.5 mGy in 54%, 70% and 75% mammography facilities (respectively) and the optical density ranged from 1.3 to 1.8. Conclusions: Results from consecutive years showed an evident tendency for decreasing radiation risk, with increasing image quality

Crucial role of perfringolysin O D1 domain in orchestrating structural transitions leading to membrane-perforating pores: a hydrogen-deuterium exchange study.

Perfringolysin O (PFO) is a toxic protein that binds to cholesterol-containing membranes, oligomerizes, and forms a β-barrel transmembrane pore, leading to cell lysis. Previous studies have uncovered the sequence of events in this multistage structural transition to a considerable detail, but the underlying molecular mechanisms are not yet fully understood. By measuring hydrogen-deuterium exchange patterns of peptide bond amide protons monitored by mass spectrometry (MS), we have mapped structural changes in PFO and its variant bearing a point mutation during incorporation to the lipid environment. We have defined all regions that undergo structural changes caused by the interaction with the lipid environment both in wild-type PFO, thus providing new experimental constraints for molecular modeling of the pore formation process, and in a point mutant, W165T, for which the pore formation process is known to be inefficient. We have demonstrated that point mutation W165T causes destabilization of protein solution structure, strongest for domain D1, which interrupts the pathway of structural transitions in other domains necessary for proper oligomerization in the membrane. In PFO, the strongest changes accompanying binding to the membrane focus in D1; the C-terminal part of D4; and strands β1, β4, and β5 of D3. These changes were much weaker for PFO(W165T) lipo where substantial stabilization was observed only in D4 domain. In this study, the application of hydrogen-deuterium exchange analysis monitored by MS provided new insight into conformational changes of PFO associated with the membrane binding, oligomerization, and lytic pore formation

R468A mutation in perfringolysin O destabilizes toxin structure and induces membrane fusion

Perfringolysin O (PFO) belongs to the family of cholesterol-dependent cytolysins. Upon binding to a cholesterol-containing membrane, PFO undergoes a series of structural changes that result in the formation of a β-barrel pore and cell lysis. Recognition and binding to cholesterol are mediated by the D4 domain, one of four domains of PFO. The D4 domain contains a conserved tryptophan-rich loop named undecapeptide (E458CTGLAWEWWR468) in which arginine 468 is essential for retaining allosteric coupling between D4 and other domains during interaction of PFO with the membrane. In this report we studied the impact of R468A mutation on the whole protein structure using hydrogen-deuterium exchange coupled with mass spectrometry. We found that in aqueous solution, compared to wild type (PFO), PFOR468A showed increased deuterium uptake due to exposure of internal toxin regions to the solvent. This change reflected an overall structural destabilization of PFOR468A in solution. Conversely, upon binding to cholesterol-containing membranes, PFOR468A revealed a profound decrease of hydrogen-deuterium exchange when compared to PFO. This block of deuterium uptake resulted from PFOR468A-induced aggregation and fusion of liposomes, as found by dynamic light scattering, microscopic observations and FRET measurements. In the result of liposome aggregation and fusion, the entire PFOR468A molecule became shielded from aqueous solution and thereby was protected against proteolytic digestion and deuteration. We have established that structural changes induced by the R468A mutation lead to exposure of an additional cholesterol-independent liposome-binding site in PFO that confers its fusogenic property, altering the mode of the toxin action