Co-Catalytic Metallopeptidases as Pharmaceutical Targets

Understanding the reaction mechanism of co-catalytic metallopeptidases provides a starting point for the design and synthesis of new molecules that can be screened as potential pharmaceuticals. Many of the enzymes that contain co-catalytic metallo-active sites play important roles in cellular processes such as tissue repair, protein maturation, hormone level regulation, cell-cycle control and protein degradation. Therefore, these enzymes play central roles in several disease states including cancer, HIV, stroke, diabetes, bacterial infections, neurological processes, schizophrenia, seizure disorders, and amyotrophic lateral sclerosis. The mechanism of AAP, an aminopeptidase from Aeromonas proteolytica, is one of the best-characterized examples of a metallopeptidase containing a co-catalytic metallo-active site, although this enzyme is not a specific pharmaceutical target at this time. As a large majority of co-catalytic metallopeptidases contain active sites that are nearly identical to the one observed in AAP, the major steps of their catalytic mechanisms are likely to be very similar. With this in mind, it is possible to propose a general catalytic mechanism for the hydrolysis of amino acid substrates

A Theoretical Model for Optimization of SALD Parameters

This paper addresses the need to conduct theoretical work concerning an economical way of Solid Freeform Fabrication rendering by using selective Area Laser Deposition (SALD). The part in SALD rendering process is formed layer by layer that, in turn, is composed of stripes of material produced in the path of a laser. There are three situations in which such a stripe can be rendered: a) alone, b) with one neighbor on one side, and c) with neighbors on both sides. Residual thermal stresses in the part are expected to be affected by how a stripe is rendered. Furthermore, the residual thermal stress and the mechanical property of the part are also dictated by other processing variables such as laser scanning patters, laser input power, scanning speed, scanning spacing, deposition temperature, gas precursor pressure, intrinsic thermal conductivity and mechanical properties of the rendered material. A theoretical approach is proposed to address the minimization of residual thermal stresses and rendering times and the maximization of the strength of the part. It is proposed that such multiple optimizations that are dictated by many decision variables can be solved by minimizing and/or maximizing object functions dePending on the design criteria for each attribute of the rendered partMechanical Engineerin

Stereometric Design for Desk-Top SFF Fabrication

Solid Freeform Fabrication (SFF) technologies refer to the fabrication of physical parts directly from computer based solid models described by STL (Stereo Lithography) or VRML (Virtual Reality Modeling Language) files generated by Computer-Aided Design (CAD) systems. Most of the SFF processes produce parts by building them layer by layer using a row by row pattern, though it is possible to build the part using other patterns. The SFF technology represents a challenge to designers who, in addition to making decisions concerning optimum shape and functionality of the entire part, have'to take under consideration several other manufacturing factors. These factors cover a wide range of technical issues such as Computer-Aided Design model generation, part description and model slicing files, laser path files, precision of part design, rendering patterns, manufacturing tolerances, thermal expansion and residual stress phenomena. This paper investigates the effect of rendering patterns on the integrity, material characteristics and mechanical properties of the parts prepared by a desk-top SFF device using diode lasers. Fe - Bronze (Cu - Sn) premixed metal powders were used as the starting material. The particle size was about 100 /lm to 200 /lm. Density, tensile strength and microstructure of the parts prepared using different rendering patterns were characterized. The results were analyzed to seek optimal rendering patterns. It was noticed that the samples were strong along the laser scanning direction, while they were weak perpendicular to the scanning direction. These results suggest that the laser scanning patterns should be designed to minimize the warping and maximize the strength of the part in the direction depending on the part's function.Mechanical Engineerin

Function of the Signal Peptide and N- and C-terminal Propeptides in the Leucine Aminopeptidase from \u3cem\u3eAeromonas proteolytica\u3c/em\u3e

The leucine aminopeptidase from Aeromonas proteolytica (also known as Vibrio proteolyticus) (AAP) is a metalloenzyme with broad substrate specificity. The open reading frame (ORF) for AAP encodes a 54 kDa enzyme, however, the extracellular enzyme has a molecular weight of 43 kDa. This form of AAP is further processed to a mature, thermostable 32 kDa form but the exact nature of this process is unknown. Over-expression of different forms of AAP in Escherichia coli (with AAP\u27s native leader sequence, with and without the N- and/or C-terminal propeptides, and as fusion protein) has allowed a model for the processing of wild-type AAP to be proposed. The role of the A. proteolytica signal peptide in protein secretion as well as comparison to other known signal peptides reveals a close resemblance of the A. proteolytica signal peptide to the outer membrane protein (OmpA) signal peptide. Over-expression of the full 54 kDa AAP enzyme provides an enzyme that is significantly less active, due to a cooperative inhibitory interaction between both propeptides. Over-expression of AAP lacking its C-terminal propeptide provided an enzyme with an identical kcat value to wild-type AAP but exhibited a larger Km value, suggesting competitive inhibition of AAP by the N-terminal propeptide (Ki∼0.13 nM). The recombinant 32 kDa form of AAP was characterized by kinetic and spectroscopic methods and was shown to be identical to mature, wild-type AAP. Therefore, the ease of purification and processing of rAAP along with the fact that large quantities can be obtained now allow new detailed mechanistic studies to be performed on AAP through site-directed mutagenesis

Żyć w zgodzie ze sobą. Desomatyzacja i nasycony głód dzieciństwa

The inspiration for this article was a project entitled “Crossing Borders: Activation of Disabled Seniors” carried out in the Daily Nursing Home run by Stowarzyszenie Przyjaciół Strzyży (Strzyża Friends’ Association) in Gdańsk, in the period between 15 June and 15 December 2015. The project focused on eliciting memories about the seniors’ past with the use of a biographical method and a narrative interview. The problems concentrate on the issue of de-somatisation and possibilities and modes of compensation. Referring to the therapeutic role of the biographical method, the author tries to find out if creating narratives supports the acquisition of sense of life and acceptance of the past in the context of traumatic childhood experiences.The inspiration for this article was a project entitled “Crossing Borders: Activation of Disabled Seniors” carried out in the Daily Nursing Home run by Stowarzyszenie Przyjaciół Strzyży (Strzyża Friends’ Association) in Gdańsk, in the period between 15 June and 15 December 2015. The project focused on eliciting memories about the seniors’ past with the use of a biographical method and a narrative interview. The problems concentrate on the issue of de-somatisation and possibilities and modes of compensation. Referring to the therapeutic role of the biographical method, the author tries to find out if creating narratives supports the acquisition of sense of life and acceptance of the past in the context of traumatic childhood experiences

Badanie możliwości wytwarzania radioizotopów za pomocą liniowych akceleratorów medycznych i analiza procedury zwiększenia dawki terapeutycznej poprzez zaaplikowanie do napromienianego obszaru nanocząstek zawierających radioizotop o dużej liczbie atomowej

Radioisotopes play an important role in nuclear medicine, both in medical diagnostics and in the development of isotope - targeted therapy. At present, there is a crisis in world radioisotope production mainly because of the exploitation of nuclear research reactors which global production of radioisotopes is based on. The answer to this situation is the search for alternative ways of making radionuclides for nuclear medicine. Within this work the possibilities of the use of the medical linear accelerators for the aforementioned purposes was checked. The high-energy photons generated in such medical linac cause photonuclear reactions (γ,n) and (γ,2n) which except of radioactve isotopes, neutrons are also produced in. These neutrons with the broad energy spectrum are the contamination of the therapeutic beam. The secondary neutron radiation can also be a source of nuclear reactions leading to the production of radioisotopes. The main aim of the thesis was to test a possibility of production of medical isotopes such as: 99Mo/99mTc, 198Au, 186Re and 188Re. The targets made of the natural elements were irradiated with the use of high-energy therapeutic 20 MV X-ray beam generated by the Varian medical linacs (Clinac 2300 and TrueBeam). The irradiations were performed at the Maria Skłodowska-Curie Memorial Cancer Centre and Institute of Oncology in Gliwice. The produced activity was determined on the base of the gamma energy spectra measured during decay of specific radioisotopes. The spectral measurements were carried out by means of the germanium detector. The research is completely innovative, there are no scientific reports with similar experiments. In this thesis the research associated with therapeutic dose enhancement was also described. The dose enhancement is obtained when the high atomic number metal nanoparticles are introduced to a target volume. This dose enhancement is caused by the increase of the photoelectric effect due to irradiation with the therapeutic megavoltage X-rays. The additional increase of a dose can be reached by means of the nanoparticles with radioactive gold atoms. Simulations were carried out using GEANT4 in version 4.9.2 installed on the Linux platform. The first part of the thesis is based on literature and available scientific publications. In the introduction the most important problems that make it possible to understand the research presented in this work were discussed. The literature section presents possible applications of radionuclides. I tested methods of their production, and briefly discribed their basic physical properties. What is more, this section describes important issues related to knowledge of current methods of production of radioisotopes and techniques of nanoparticle synthesis including gold nanoparticles. The methodology of measurements and calculations is described in the second part of the thesis. This section presents an innovative radionuclide production technique using medical linear accelerators available in each oncology center. Moreover, this chapter summarizes qualitative data analysis methods in a brief manner, including computational methods. The experimental part presents the spectra of gamma radiation emitted by radioactive isotopes recorded by means of semiconductor detectors, decay schemes of radionuclide, and cross sections for typical reactions occurring in target materials during the emission of high energy therapeutic beams. The rest of this chapter includes the results of experiments based on well known production methods. A discussion of the results of experiments taken from the specialist literature has the advantage that in the following part of this thesis facilitates the interpretation of the obtained results. It allows to estimate the effectiveness of the proposed method of production of radioactive isotopes used in nuclear medicine. The six chapter presents the structure of simulation programs based on the Monte Carlo techniques. A separate chapter (the chapter seven) presents the results of experiments and calculations. The obtained results were compared with literature data and summarized in the chapter eight

Verification of the use of GEANT4 and MCNPX Monte Carlo codes for calculations of the depth-dose distributions in water for the proton therapy of eye tumours

Verification of calculations of the depth-dose distributions in water, using GEANT4 (version of 4.9.3) and MCNPX (version of 2.7.0) Monte Carlo codes, was performed for the scatterer-phantom system used in the dosimetry measurements in the proton therapy of eye tumours. The simulated primary proton beam had the energy spectra distributed according to the Gauss distribution with the cut at energy greater than that related to the maximum of the spectrum. The energy spectra of the primary protons were chosen to get the possibly best agreement between the measured relative depth-dose distributions along the central-axis of the proton beam in a water phantom and that derived from the Monte Carlo calculations separately for the both tested codes. The local depth-dose differences between results from the calculations and the measurements were mostly less than 5% (the mean value of 2.1% and 3.6% for the MCNPX and GEANT4 calculations). In the case of the MCNPX calculations, the best fit to the experimental data was obtained for the spectrum with maximum at 60.8 MeV (more probable energy), FWHM of the spectrum of 0.4 MeV and the energy cut at 60.85 MeV whereas in the GEANT4 calculations more probable energy was 60.5 MeV, FWHM of 0.5 MeV, the energy cut at 60.7 MeV. Thus, one can say that the results obtained by means of the both considered Monte Carlo codes are similar but they are not the same. Therefore the agreement between the calculations and the measurements has to be verified before each application of the MCNPX and GEANT4 codes for the determination of the depth-dose curves for the therapeutic protons

Test of production of 198Au radioisotope by means of typical medical linear accelerators used in teleradiotherapy

The test of production of the Au-198 radioisotope by means of Varian medical linear accelerators used in teleradiotherapy was carried out. The targets made of the natural gold (100% of the Au-197 isotope) were irradiated with high-energy therapeutic 20 MV X-ray beam. Au-198 was produced in the simple capture reaction Au-197(n, gamma) Au-198. The obtained specific activities in the saturation state are relatively low, not exceeding the value of 510.4 kBq/g, because only the high-energy part of the spectrum of 20 MV X-ray beam covers the energy range of the neutron production cross section. Low activity of the Au-198 radioisotope produced by medical linear accelerators makes this technique not suitable for a massive production of Au-198 for nuclear medicine, but the produced amount of Au-198 is sufficient for laboratory tests of new drugs for possible clinical applications

The effect of surface seal catchment on the size of strom water runoff

Natural areas are often converted into paved or sealed surfaces. The degree of surface sealing, public transport and hydrotechnical infrastructure significantly alter the rainfall-runoff relationship in the area. All these factors entail consequences which often result in numerous and severe floods. The paper assesses the impact of surface conditions on the size of storm water runoff from both natural and urban area and the impact of seals on land runoff hydrographs