[Clinical and ultrasonic predictors of postoperative complications after carotid endarterectomy].

For the period from 2007 to 2012 carotid endarterectomy was performed in 150 patients with cerebrovascular insufficiency I-IV degrees and atherosclerotic lesion of carotid arteries. Dynamic observation was performed by using of duplex scanning of brachiocephalic arteries, transcranial duplex scanning, multislice CT with contrast study of extracranial and intracranial arteries. Different degrees of vascular wall thickening of operated internal carotid artery including neo- and myointimal hyperplasia, restenosis and other complications were observed in 19 (12.6%) patients after carotid endarterectomy on background of cerebrovascular insufficiency progressing. It was revealed that transient ischemic attack or stroke, acute heart failure in early postoperative period, arterial hypertension with crisis course predominantly, diabetes mellitus 2 type, obesity, male sex, elderly age and smoking were clinical markers for complications after carotid endarterectomy. Ultrasonic markers of complications after carotid endarterectomy included terms of development and degree of vascular wall thickening in case of neointimal hyperplasia and restenosis, hyperperfusion syndrome and stroke, significant changes of blood flow velocity and indexes of peripheral vascular resistance.

[Surgical treatment of hemodynamically significant kinking of internal carotid arteries].

38 patients with different forms of vascular cerebral insufficiency, caused by kinking and atherosclerotic changes of internal carotid arteries were operated on. Various types of reconstructive operation on extracranial carotid arteries were performed. The color duplex ultrasound scanning and computed tomography proved to be highly informative noninvasive means for detecting carotid pathology in patients with vascular cerebral insufficiency. Reconstructive operations on internal carotid arteries can serve as prophylactic and treatment measure of chronic cerebral insufficiency. Authors propose the principle of "six types" of reconstructive operations which individualizes the surgical approach. Carotid surgery for asympomatic patients should be performed on strict indications.

[Surgical prophylaxis of pulmonary embolism].

144 patients were operated on for deep vein thrombosis. Color duplex lower limb vessels scanning was he basic diagnostic procedure performed preoperatively. Operative treatment corresponded floating trombectomy and main vein placation as a means of pulmonary embolism prophylaxis. Thrombosis located in deep tibial veins (65.9%), deep femoral vein (12.5%), popliteal vein (9.7%), femoral vein (8.4%) and lower limb subcutaneous veins (3.5%). 88,9% of thrombs were considered as floating. Thrombectomy was performed in 90.9%, exclusion was made for the popliteal localization of occlusion. Partial main veins occlusion was performed in 94.4%. The procedure was rejected in cases of successful complete embolus evacuation (2.1%) or subcutaneous thrombosis localization. Long-term follow-up (15.35+/-7.7 months) revealed complete plication area recanalization in 85.9%, the rest patients demonstrated partial recanalization, though with a substantial blood flow improvement.

[Tobacco etch virus proteinase: crystal structure of the active enzyme and its inactive mutant]. / Proteinaza virusa gravirovki tabaka: kristallicheskaia struktura aktivnogo fermenta i ego neaktivnogo mutanta.

Tobacco Etch Virus Protease (TEV protease) is widely used as a tool for separation of recombinant target proteins from their fusion partners. The crystal structures of two mutants of TEV protease, active autolysis-resistant mutant TEV-S219D in complex with the proteolysis product, and inactive mutant TEV-C151A in complex with a substrate, have been determined at 1.8 and 2.2 A resolution, respectively. The active sites of both mutants, including their oxyanion holes, have identical structures. The C-terminal residues 217-221 of the enzyme are involved in formation of the binding pockets S3-S6. This indicates that the autolysis of the peptide bond Met218-Ser219 exerts a strong effect on the fine-tuning of the substrate in the enzyme active site, which results in considerable decrease in the enzymatic activity.

Unusual molecular architecture of the Yersinia pestis cytotoxin YopM: a leucine-rich repeat protein with the shortest repeating unit.

Many Gram-negative bacterial pathogens employ a contact-dependent (type III) secretion system to deliver effector proteins into the cytosol of animal or plant cells. Collectively, these effectors enable the bacteria to evade the immune response of the infected organism by modulating host-cell functions. YopM, a member of the leucine-rich repeat protein superfamily, is an effector produced by the bubonic plague bacterium, Yersinia pestis, that is essential for virulence. Here, we report crystal structures of YopM at 2.4 and 2.1 A resolution. Among all leucine-rich repeat family members whose atomic coordinates have been reported, the repeating unit of YopM has the least canonical secondary structure. In both crystals, four YopM monomers form a hollow cylinder with an inner diameter of 35 A. The domain that targets YopM for translocation into eukaryotic cells adopts a well-ordered, alpha-helical conformation that packs tightly against the proximal leucine-rich repeat module. A similar alpha-helical domain can be identified in virulence-associated leucine-rich repeat proteins produced by Salmonella typhimurium and Shigella flexneri, and in the conceptual translation products of several open reading frames in Y. pestis.

Structure of the N-terminal domain of Yersinia pestis YopH at 2.0 A resolution.

Yersinia pestis, the causative agent of bubonic plague, injects effector proteins into the cytosol of mammalian cells that enable the bacterium to evade the immune response of the infected organism by interfering with eukaryotic signal transduction pathways. YopH is a modular effector composed of a C-terminal protein tyrosine phosphatase (PTPase) domain and a multifunctional N-terminal domain that not only orchestrates the secretion and translocation of YopH into eukaryotic cells but also binds tyrosine-phosphorylated target proteins to mediate substrate recognition. The crystal structure of the N-terminal domain of YopH (YopH(N); residues 1-130) has been determined at 2.0 A resolution. The amino-acid sequences that target YopH for secretion from the bacterium and translocation into eukaryotic cells form integral parts of this compactly folded domain. The structure of YopH(N) bears no resemblance to eukaryotic phosphotyrosine-binding domains, nor is it reminiscent of any known fold. Residues that have been implicated in phosphotyrosine-dependent protein binding are clustered together on one face of YopH(N), but the structure does not suggest a mechanism for protein-phosphotyrosine recognition.

Structural basis for oligosaccharide recognition by Pyrococcus furiosus maltodextrin-binding protein.

A maltodextrin-binding protein from Pyrococcus furiosus (PfuMBP) has been overproduced in Escherichia coli, purified, and crystallized. The crystal structure of the protein bound to an oligosaccharide ligand was determined to 1.85 A resolution. The fold of PfuMBP is very similar to that of the orthologous MBP from E. coli (EcoMBP), despite the moderate level of sequence identity between the two proteins (27 % identity, 46 % similarity). PfuMBP is extremely resistant to heat and chemical denaturation, which may be attributed to a number of factors, such as a tightly packed hydrophobic core, clusters of isoleucine residues, salt-bridges, and the presence of proline residues in key positions. Surprisingly, an attempt to crystallize the complex of PfuMBP with maltose resulted in a structure that contained maltotriose in the ligand-binding site. The structure of the complex suggests that there is a considerable energy gain upon binding of maltotriose in comparison to maltose. Moreover, isothermal titration calorimetry experiments demonstrated that the binding of maltotriose to the protein is exothermic and tight, whereas no thermal effect was observed upon addition of maltose at three temperatures. Therefore, PfuMBP evidently is designed to bind oligosaccharides composed of three or more glucopyranose units.

Overproduction, purification, crystallization and preliminary X-ray diffraction analysis of YopM, an essential virulence factor extruded by the plague bacterium Yersinia pestis.

A recombinant form of Yersinia pestis YopM with a C-terminal polyhistidine affinity tag has been overproduced in Escherichia coli, purified to homogeneity and crystallized using the hanging-drop vapor-diffusion technique. Several different crystal forms were obtained. The most suitable crystals for X-ray diffraction belonged to space groups P4(2)22 (unit-cell parameters a = 109.36, b = 109.36, c = 101.50 A) and C222(1) (unit-cell parameters a = 71.73, b = 121. 85, c = 189.79 A). With a synchrotron-radiation source, these crystals diffracted to 2.4 and 1.9 A resolution, respectively.

Anti-human immunodeficiency virus activity of novel aminoglycoside-arginine conjugates at early stages of infection.

Conjugates of L-arginine with aminoglycosides have already been described as potent in vitro inhibitors of the HIV-1 Tat-trans-activation responsive element interaction. The polycationic nature of these agents leads us to suggest that they may be active against HIV-1 replication by inhibiting earlier stages of the virus life cycle. We have found that R4K and R3G, kanamycin A, and gentamicin C, conjugated with arginine, inhibited HIV-1 NL4-3 replication at EC50 values of 15 and 30 microM for R3G and R4K, respectively, without a detectable tonic effect on MT-4 cells at concentrations higher than 4000 and about 1000 microM, respectively. Both compounds inhibited the binding of a monoclonal antibody (12G5) directed to CXCR4 as well as the intracellular Ca2+ signal induced by the chemokine SDF-1alpha on CXCR4+ cells, suggesting that aminoglycoside-arginine conjugates interact with CXCR4, the coreceptor used by T-tropic, X4 strains of HIV-1. On the other hand, CB4K, a conjugate of kanamycin A with gamma-guanidinobutyric acid, structurally similar to R4K, failed to display any anti-HIV activity of CXCR4 antagonist activity. An HIV-1 strain that was made resistant to the known CXCR4 antagonist AMD3100 was cross-resistant to both R4K and R3G. However, unlike SDF-1alpha and R4K, R3G inhibited the binding of HIV-1 to MT-4 cells. Aminoglycoside-arginine conjugates inhibit HIV replication by interrupting the early phase of the virus life cycle, namely virus binding to CD4 cells and interaction with CXCR4. R3G and R4K may serve as prototypes of novel anti-HIV agents and should be further studied.

Aminoglycoside-arginine conjugates that bind TAR RNA: synthesis, characterization, and antiviral activity.

Regulation of HIV gene expression is crucially dependent on binding of the trans-activator protein, Tat, to the trans-activation response RNA element, TAR, found at the 5' end of all HIV-1 transcripts. Tat-TAR interaction is mediated by a short arginine-rich domain of the protein. Disruption of this interaction could, in theory, create a state of complete viral latency. A new class of small-molecule peptidomimetic TAR RNA binders, conjugates of aminoglycosides and arginine, was recently designed [Litovchick, A., Evdokimov, A. G., and Lapidot, A. (1999) FEBS Lett. 445, 73-79]. Two of these compounds, the tri-arginine derivative of gentamicin C (R3G) and the tetra-arginine derivative of kanamycin A (R4K), bind efficiently and specifically to TAR RNA. These compounds display negligible toxicity while being transported and accumulated in cell nuclei. Here we present a detailed synthesis and chemical characterization of the aminoglycoside-arginine conjugates R3G and R4K as well as GB4K, the tetra-gamma-guanidinobutyric derivative of kanamycin A. Their binding sites on TAR RNA were assigned by RNase A, uranyl nitrate, and lead acetate footprinting. The conjugates interact with TAR RNA in the widened major groove, formed by the UCU bulge and the neighboring base pairs of the upper stem portion of TAR, the binding site of Tat protein, and Tat-derived peptides (e.g., R52). Our results suggest an additional binding site of R4K and R3G compounds, in the lower stem-bulge region of TAR. The antiviral activity of the conjugates in cultured equine dermal fibroblasts infected with equine infectious anemia virus, used as a model system of HIV-infected cells, is also presented.

[Use of porous polytetrafluoroethylene prostheses in reconstructive reoperations in patients with occlusive lesions of the aorta and arteries of the lower limbs]. / Primenenie protezov iz poristogo politetraftorétilena pri povtornykh rekonstruktivnykh operatsiiakh u bol'nykh s okkliuzionnymi porazheniiami aorty i arterii nizhnikh konechnostei.

The use of a new domestic vascular prosthesis "Vitaflon" in reconstructive reoperations on 21 patients was clinically estimated. The positive properties of the prosthesis such as high biological inertia, good plastic properties, strength and reliability allow this prosthesis to be recommended for using in reconstructive reoperations on the vessels.

Arginine-aminoglycoside conjugates that bind to HIV transactivation responsive element RNA in vitro.

HIV gene expression is crucially dependent on binding of the viral Tat protein to the transactivation RNA response element. A number of synthetic Tat-transactivation responsive element interaction inhibitors of peptide/peptoid nature were described as potential antiviral drug prototypes. We present a new class of peptidomimetic inhibitors, conjugates of L-arginine with aminoglycosides. Using a gel-shift assay and affinity chromatography on an L-arginine column we found that these compounds bind specifically to the transactivation responsive element RNA in vitro with Kd values in the range of 20-400 nM, which is comparable to the Kd of native Tat bound to the transactivation responsive element (10-12 nM). Confocal microscopy studies demonstrated that fluorescein-labelled conjugate penetrates into live cells. High affinity to the transactivation responsive element, low toxicity, and relative simplicity of synthesis make these compounds attractive candidates for antiviral drug design.

[Analysis of some parameters for determining myocardial contractility before and after aortocoronary shunting]. / Analiz nekotorykh parametrov v opredelenii sokratitel'noi funktsii miokarda do i posle aorto-koronarnogo shuntirovaniia

The condition of hemodynamics and the contractile function of the myocardium are considered before and after aorto-coronary shunting performed in patients with critically severe affection of the coronary arteries and the heart muscle. Of great prognostic importance is the final diastolic volume of the ventricles, its relation to the stroke ejection, as well as the ejection fraction. The greater the final diastolic volume of the ventricle and the smaller the stroke ejection, the higher is the risk of applying operative treatment to the patient.