[The role of the vascular surgeon in improvement of organization of dialysis help]. / Rol' angiokhirurga v uluchshenii organizatsii dializnoi pomoshchi.

Analysed herein are one-year results of formation of arteriovenous fistulas in 109 patients with end-stage chronic renal failure, as well as therapeutic decision-making after angiosurgical counselling of 144 patients presenting with 'problem' permanent vascular accesses. The counselling and formation of arteriovenous fistulas were carried out in conditions of interdepartmental collaboration between outpatient centres dealing with haemodialysis and vascular surgeons specialized in ultrasound mapping of peripheral vessels and performing different variants of arteriovenous fistulas. The angiosurgical care was as close to the patient as possible. Of the 109 operated patients, primary arteriovenous fistulas were made in 46 (42.2%) cases, secondary AVF - in 27 (24.8%) cases, and reconstruction of AVF - in 36 (33.0%) cases. Of the 144 patients with 'problem' permanent vascular assesses, correction of arteriovenous fistulas turned out impossible in 13 (9.1%). In the remaining 131 (90.9%) patients there was a possibility of different variants of open reconstruction of arteriovenous fistulas or performing angioplasty. Active policy of vascular surgeons in interdepartmental collaboration with nephrologists made it possible to bridge over the difficulties of patients routing which resulted in reduction of the terms of formation of arteriovenous fistulas by 2 months. Preventive arteriovenous fistulas were carried out in 17.4% of cases of primary permanent vascular assesses. During a year after formation of permanent vascular accesses, the number of patients with vascular catheters in ambulatory centres decreased from 22 to 17%. These positive changes in organization of the dialysis treatment made it possible to reduce the risks of infectious complications, to obtain adequate blood flow characteristics for haemodialysis procedures, as well as to decrease financial expenses and labour costs for AVF care.

Structural study of the X-ray-induced enzymatic reduction of molecular oxygen to water by Steccherinum murashkinskyi laccase: insights into the reaction mechanism.

The laccase from Steccherinum murashkinskyi is a member of the large family of multicopper oxidases that catalyze the oxidation of a wide range of organic and inorganic substrates, accompanied by the reduction of dioxygen to water. The reducing properties of X-ray radiation and the high quality of the laccase crystals allow the study of the catalytic reduction of dioxygen to water directly in a crystal. A series of diffraction data sets with increasing absorbed radiation dose were collected from a single crystal of Steccherinum murashkinskyi laccase at 1.35 Šresolution. Changes in the active-site structure associated with the reduction of molecular oxygen to water on increasing the absorbed dose of ionizing radiation were detected. The structures in the series are mixtures of different states of the enzyme-substrate complex. Nevertheless, it was possible to interpret these structures as complexes of various oxygen ligands with copper ions in different oxidation states. The results allowed the mechanism of oxygen reduction catalyzed by laccases to be refined.

Structural study of the X-ray-induced enzymatic reaction of octahaem cytochrome C nitrite reductase.

Octahaem cytochrome c nitrite reductase from the bacterium Thioalkalivibrio nitratireducens catalyzes the reduction of nitrite to ammonium and of sulfite to sulfide. The reducing properties of X-ray radiation and the high quality of the enzyme crystals allow study of the catalytic reaction of cytochrome c nitrite reductase directly in a crystal of the enzyme, with the reaction being induced by X-rays. Series of diffraction data sets with increasing absorbed dose were collected from crystals of the free form of the enzyme and its complexes with nitrite and sulfite. The corresponding structures revealed gradual changes associated with the reduction of the catalytic haems by X-rays. In the case of the nitrite complex the conversion of the nitrite ions bound in the active sites to NO species was observed, which is the beginning of the catalytic reaction. For the free form, an increase in the distance between the oxygen ligand bound to the catalytic haem and the iron ion of the haem took place. In the case of the sulfite complex no enzymatic reaction was detected, but there were changes in the arrangement of the active-site water molecules that were presumably associated with a change in the protonation state of the sulfite ions.

[A mice model of amyotrophic lateral sclerosis expressing mutant human FUS protein].

UNLABELLED: BACKGROUND AND ОBJECTIVE: Loss of conformation and function of sufficient number of proteins with high aggregation capacity plays an important role in the pathogenesis of many neurodegenerative disorders (NDD). Due to a recent discovery of new array of proteins with the capacity to form aggregates of nonamyloid type, new NDD models as well as a new level of understanding in vivo models which are already exist is needed. DNA/RN A binding proteins - FUS and TDP-43 play a crucial role in the pathogenesis of some forms of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia. The objective of the study was to develop a new ALS transgenic model. MATERIAL AND METHODS: In cell culture experiments, we studied mutant FUS proteins capable to form intracellular deposits morphologically similar to those observed in the autopsy material of ALS patients. RESULTS AND CONCLUSION: We created a transgenic mice line, in which a pathogenic form of human FUS protein was expressed in the nervous system. That led to the aggregation of FUS protein in spinal cord and motor neurons with the following degeneration and development of a phenotype, similar to the human ALS disease phenotype, in young grown-up animals. This neurodegenerative phenotype corresponds to a great number of clinical manifestations of human ALS and is an adequate transgenic model of the disease.

[Evolution of ultrasonic indices of the heart and arteriovenous fistulas in patients on chronic haemodialysis].

The authors assessed the ultrasonic evolution of haemodynamics of arteriovenous fistulas (AVFs), cardiohaemodynamics, and the dimensions of the heart chambers in a total of thirty-five patients presenting with terminal chronic renal insufficiency (TCRI) and being on chronic haemodialysis (CHD). A further thirteen patients without TCRI composed the control group. The TCRI patients were subdivided into two groups: Group One (n=20) with a distal variant of the Cimino-type AVF, 21 vascular accesses, and Group Two (n=15) with a proximal variant of AFV, 16 accesses using a synthetic vascular prosthesis (SVP). The terms of follow up of the TCRI patients were as follows: day 12, months 1, 3, 6 and 12 after creating the AVF. 12 days after creating the AVF there were no differences in the parameters of cardiohaemodynamics and the dimensions of the cardiac chambers between Group I and II. As compared with the control, the both groups of the patients with TCRI at these terms demonstrated increased sizes of the left ventricle (LV). The dynamic follow up during the subsequent periods showed that Group One and Group Two patients had no statistically significant differences in the parameters studied, however, patients of the both study groups were found to have a trend toward increased dimensions of the right chambers of the heart, not exceeding the limits of the norm of these indices. The volumetric velocity of the blood flow (BFVV) through the Cimino-type AVF during 12 months had a tendency towards a graduate growth up to 800 ml/min, whereas the proximal fistulas were characterized by stable indices of the BFVV at a level of 900 ml/min. The revealed alterations in the right chambers of the heart after creating the AVF required no surgical correction of the volumetric blood flow through the AVF during the follow up period up to 12 months.

Production of human lactoferrin in animal milk.

Genetic constructs containing the human lactoferrin (hLf) gene were created within a joint program of Russian and Belorussian scientists. Using these constructs, transgenic mice were bred (the maximum hLf concentration in their milk was 160 g/L), and transgenic goats were also generated (up to 10 g/L hLf in their milk). Experimental goatherds that produced hLf in their milk were also bred, and the recombinant hLf was found to be identical to the natural protein in its physical and chemical properties. These properties included electrophoretic mobility, isoelectric point, recognition by polyclonal and monoclonal antibodies, circular dichroic spectra, interaction with natural ligands (DNA, lipopolysaccharides, and heparin), the binding of iron ions, the sequence of the 7 terminal amino acids, and its biological activity. The latter was assessed by the agglutination of Micrococcus luteus protoplasts, bactericidal activity against Escherichia coli and Listeria monocytogenes , and fungicidal activity against Candida albicans . We also demonstrated a significant increase in the activity of antibiotics when used in combination with Lf.

Three-dimensional structures of L-asparaginase from Erwinia carotovora complexed with aspartate and glutamate.

The crystal structures of Erwinia carotovora L-asparaginase complexed with L-aspartate and L-glutamate were determined at 1.9 and 2.2 A, respectively, using the molecular-replacement method and were refined to R factors of about 21% in both cases. The positions of the ligands in the active site were located. A comparison of the new structures with the known structures of Escherichia coli L-asparaginase and Er. chrysanthemi L-asparaginase was performed. It was found that the arrangement of the ligands practically coincides in all three enzymes. The peculiarities of the quaternary structure of the enzyme, the possible role of water molecules in the enzyme action and the conformational changes during the catalyzed reaction are discussed.

Reversible inhibition of Escherichia coli inorganic pyrophosphatase by fluoride: trapped catalytic intermediates in cryo-crystallographic studies.

Here, we describe high-resolution X-ray structures of Escherichia coli inorganic pyrophosphatase (E-PPase) complexed with the substrate, magnesium, or manganese pyrophosphate. The structures correspond to steps in the catalytic synthesis of enzyme-bound pyrophosphate (PP(i)) in the presence of fluoride as an inhibitor of hydrolysis. The catalytic reaction intermediates were trapped applying a new method that we developed for initiating hydrolytic activity in the E-PPase crystal. X-ray structures were obtained for three consecutive states of the enzyme in the course of hydrolysis. Comparative analysis of these structures showed that the Mn2+-supported hydrolysis of the phosphoanhydride bond is followed by a fast release of the leaving phosphate from the P1 site. The electrophilic phosphate P2 is trapped in the "down" conformation. Its movement into the "up" position most likely represents the rate-limiting step of Mn2+-supported hydrolysis. We further determined the crystal structure of the Arg43Gln mutant variant of E-PPase complexed with one phosphate and four Mn ions.

Crystallization and preliminary X-ray analysis of cytochrome c nitrite reductase from Thioalkalivibrio nitratireducens.

A novel cytochrome c nitrite reductase (TvNiR) was isolated from the haloalkalophilic bacterium Thioalkalivibrio nitratireducens. The enzyme catalyses nitrite and hydroxylamine reduction, with ammonia as the only product of both reactions. It consists of 525 amino-acid residues and contains eight haems c. TvNiR crystals were grown by the hanging-drop vapour-diffusion technique. The crystals display cubic symmetry and belong to space group P2(1)3, with unit-cell parameter a = 194 A. A native data set was obtained to 1.5 A resolution. The structure was solved by the SAD technique using the data collected at the Fe absorption peak wavelength.

[Immunologic assessment of the risk of developing infectious-inflammatory complications after percutaneous operations for nephrolithiasis]. / Immunologicheskaia otsenka riska razvitiia infektsionno-voxpalitel'nykh osloznenii posle perkutannyklh operatsii pri nefrolitiaze.

A retrospective comparison of the evidence obtained at preoperative examination of 68 patients with urolithiasis operated with the use of percutaneous technologies has demonstrated that the risk of postoperative infectious-inflammatory complications depends much on the immune status of the patient. Patients with initially different states of phagocytic immunity and antibody production had different courses of the postoperative period. An algorithm of immunological prediction of an acute pyelonephritis attack after percutaneous operations for nephrolithiasis is proposed.

[Blood level of lipid peroxidation products as an indicator of resistance to infectious inflammatory complications of transurethral electroresection of the prostate]. / Soderzhanie produktov lipoperoksidatsii v krovi kak pokazatel' ustoichivosti k infektsionno-vaspalitel'nym oslozhneniiam transuretal'noi élektrorezektsii predstatel'noi zhelezy.

Study of relationship between the content of lipid peroxidation (LPO) products in the blood of patients with benign prostatic hyperplasia (BPH) and resistance to infectious inflammatory complications (IIC) of transurethral electroresection of the prostate showed that decreased content of circulating lipoperoxides promoted the development of postoperative IIC. Before the operation blood levels of LPO products were increased in BPH patients who did not develop IIC postoperation in comparison with normal controls. Three intravenous injections of ascorbic acid in a single dose of 1000 mg after transurethral electroresection of the prostate led to an increase in the blood level of LPO products and promoted a decrease in the incidence of postoperative IIC.

Morphometric parameters of inflammatory infiltration in renal tissue and personality characteristics of patients at risk of pyelonephritis attack after percutaneous nephrolithotomy.

A correlation between personality traits and the type of inflammatory infiltration in the renal pelvicalyceal system was revealed in patients with nephrolithiasis. The study demonstrated the possibility of indirect evaluation of the inflammatory process in the pelvicalyceal system and preoperative prediction of acute pyelonephritis attack after percutaneous nephrolithotomy on the basis of patient's psychological status.

The structures of Escherichia coli inorganic pyrophosphatase complexed with Ca(2+) or CaPP(i) at atomic resolution and their mechanistic implications.

Two structures of Escherichia coli soluble inorganic pyrophosphatase (EPPase) complexed with calcium pyrophosphate (CaPP(i)-EPPase) and with Ca(2+) (Ca(2+)-EPPase) have been solved at 1.2 and 1.1 A resolution, respectively. In the presence of Mg(2+), this enzyme cleaves pyrophosphate (PP(i)) into two molecules of orthophosphate (P(i)). This work has enabled us to locate PP(i) in the active site of the inorganic pyrophosphatases family in the presence of Ca(2+), which is an inhibitor of EPPase.Upon PP(i) binding, two Ca(2+) at M1 and M2 subsites move closer together and one of the liganded water molecules becomes bridging. The mutual location of PP(i) and the bridging water molecule in the presence of inhibitor cation is catalytically incompetent. To make a favourable PP(i) attack by this water molecule, modelling of a possible hydrolysable conformation of PP(i) in the CaPP(i)-EPPase active site has been performed. The reasons for Ca(2+) being the strong PPase inhibitor and the role in catalysis of each of four metal ions are the mechanistic aspects discussed on the basis of the structures described.

Improving the X-ray resolution by reversible flash-cooling combined with concentration screening, as exemplified with PPase.

A significant improvement in the X-ray resolution of crystals of Escherichia coli inorganic pyrophosphatase at cryotemperature was obtained as a result of studying the relationship between the crystal order and cryosolution component concentrations. To perform the experiments, the ability to reverse the flash-cooling process and to return a crystal to ambient temperature was used. In each cycle, the crystal was transferred from a cold nitrogen-gas stream to a cryosolution with modified concentrations of the components. The crystal was then flash-cooled again and the diffraction quality checked. Such a technique allows the screening of a wide concentration range rather quickly without using a large number of crystals and allows the determination of optimal cryosolution component concentrations. The resolution limit for crystals of pyrophosphatase increased by almost 0.7 A, from 1.8 to 1.15 A.

Preoperative immune status and lipid peroxidation as risk markers for pyelonephritis attack after percutaneous nephrolithotomy.

Pyelonephritis attack after percutaneous nephrolithotomy can be predicted on the basis of immunity parameters and blood level of lipid peroxides.

A steric mechanism for inhibition of CO binding to heme proteins.

The crystal structures of myoglobin in the deoxy- and carbon monoxide-ligated states at a resolution of 1.15 angstroms show that carbon monoxide binding at ambient temperatures requires concerted motions of the heme, the iron, and helices E and F for relief of steric inhibition. These steps constitute the main mechanism by which heme proteins lower the affinity of the heme group for the toxic ligand carbon monoxide.

The binding of carbon monoxide and nitric oxide to leghaemoglobin in comparison with other haemoglobins.

Haemoglobins have the ability to discriminate between oxygen and other diatomic molecules. To further understanding of this process the X-ray crystal structures of carbonmonoxy and nitrosyl-leghaemoglobin have been determined at 1.8 A resolution. The ligand geometry is discussed in detail and the controversial issue of bent versus linear carbon monoxide binding is addressed. The bond angle of 160 degrees for CO-leghaemoglobin is in conflict with recent spectroscopy results on myoglobin but is consistent with angles obtained for myoglobin X-ray crystal structures. In contrast to the numerous carbon monoxide studies, very little stereochemical information is available for the nitric oxide adduct of haemoglobin. This is provided by the X-ray structure of NO-leghaemoglobin, which conforms to expected geometry with an Fe-NO angle of 147 degrees and a lengthened iron-proximal histidine bond. Thus crystallographic evidence is given for the predicted weakening of this bond on the binding of nitric oxide.

[A method for extrafocal controllable wound closure and an adaptable repositioning device]. / Sposob vneochagovogo kontroliruemogo vul'nosinteza i adaptatsionno-repozitsionnoe ustroistvo dlia ego osushchestvleniia.

For quicker healing of vast long-standing wounds the authors propose a specially developed device-wound contractors accelerating processes of contraction. Experimental investigations have shown that processes of concentric contraction depend on the shape and are most typical of wounds having the appearance of extended rectangle. Promising clinical results were obtained in treatment of 17 patients with vast defects of tissues of different localization (trunk--10, femur--3, shoulder--2, head--2).