[Gastrointestinal Bleeding in Patients with Coronary Heart Disease: Preventive Options].

Extensive use of antithrombotic drugs (ATD) in patients with ischemic heart disease (IHD), on the one hand, provides a considerable decrease in the risk for development of life-threatening cardiovascular complications but on the other hand, is associated with a risk of gastrointestinal bleedings (GIB), which may develop in 0.5-1.0 % of patients. In such cases, the major measures for prevention of GIB are strict adherence to indications for the ATD treatment, detection and analysis of risk factors for GIB and their elimination as far as feasible. For evaluation of GIB risk in patients with IHD, the PRECISE-DAPT and DAPT, HAS-BLED scales should be used. If the risk factors are non-modifiable the therapeutic tactics for further management of these patients should be strictly individual with determining the nature of damage, degree of a risk for present and possible complications, and the range of required therapeutic and diagnostic measures. The use of ATD requires monitoring of the patient's condition to timely detect and treat GI complications.

[The mode of evaluation of sensibilization of children to grain herbs under respiratory allergy.]

The sensibilization of patients to allergens of grain herbs is characterized by expressed crossed allergic reactions to pollen of various representatives of the given family. The investigation of antibody response to allergens of grain herbs and also data of epidemiological studies, results of world and national studies permitted to develop and propose a new mode of diagnostic of allergy with evaluation of level of sensibilization of patient and also qualitative detection in blood serum the level of specific immunoglobulins E (IgE) to allergens of grain herbs. The parameter «concentration of IgE to allergens of cocksfoot¼ - IgE(g3) - is a key one for evaluating in blood serum of patients content of IgE to allergens of grain herbs matched to cocksfoot: randall, timothy, Kentucky bluegrass, field brome, meadow foxtail, French ryegrass. To calculate concentration of IgE to allergens of the mentioned grasses detection of IgE(g3) is necessary and sufficient. The elaborated prognostic table permits evaluating degree of ensibilization of patient to various grain herbs and also detecting concentration of IgE expressed in units kE per l without application of additional serological analyses. Therefore, the elaborated technique permits reducing number of «in vitro¼ tests and minimizing number of blood sample of patient and also speeding up receiving of information concerning sensibilization profile of patient.

Human Interleukin-2 and Hen Egg White Lysozyme: Screening for Bacteriolytic Activity against Various Bacterial Cells.

The bacteriolytic activity of interleukin-2 and hen egg white lysozyme against 34 different species of microorganisms has been studied. It was found that 6 species of microorganisms are lysed in the presence of interleukin-2. All interleukin-2-sensitive microorganisms belong either to the Enterobacteriaceae, Bacillaceae, or the Lactobacillaceae family. It was also found that 12 species of microorganisms are lysed in the presence of lysozyme, and 16 species of microorganisms are lysed in the presence of sodium dodecyl sulfate (SDS). The bacteriolytic activity of interleukin-2 and lysozyme was studied at various pH values.

Additivity of the Stabilization Effect of Single Amino Acid Substitutions in Triple Mutants of Recombinant Formate Dehydrogenase from the Soybean Glycine max.

Recently, we demonstrated that the amino acid substitutions Ala267Met and Ala267Met/Ile272Val (Alekseeva et al., Biochemistry, 2012), Phe290Asp, Phe290Asn and Phe290Ser (Alekseeva et al., Prot. Eng. Des. Select, 2012) in recombinant formate dehydrogenase from soya Glycine max (SoyFDH) lead to a significant (up to 30-100 times) increase in the thermal stability of the enzyme. The substitutions Phe290Asp, Phe290Asn and Phe290Ser were introduced into double mutant SoyFDH Ala267Met/Ile272Val by site-directed mutagenesis. Combinations of three substitutions did not lead to a noticeable change in the catalytic properties of the mutant enzymes. The stability of the resultant triple mutants was studied through thermal inactivation kinetics and differential scanning calorimetry. The thermal stability of the new mutant SoyFDHs was shown to be much higher than that of their precursors. The stability of the best mutant SoyFDH Ala267Met/Ile272Val/Phe290Asp turned out to be comparable to that of the most stable wild-type formate dehydrogenases from other sources. The results obtained with both methods indicate a great synergistic contribution of individual amino acid substitutions to the common stabilization effect.

[Topical issues of food allergy diagnosis in pediatric practice].

Food allergy (FA) in children, especially in infancy, is still a significant public health problem. The severity and prognosis of disease progression associated with FA considerably depends on the correct and early diagnostics of this pathology, as well as on the following management of a child. At the same time delayed elimination diet administration, unreasonable or overlong dietary intervention might have become abuse management of a patient and have a negative impact on the development of a child and reduce the quality of life. The article summarizes the current practical approaches to the diagnosis of FA based on evidence-based medicine and adopted European and Russian national consensus documents, as well as on our own experience of management of patients with this pathology. FA diagnosis in a child usually includes clinical laboratory tests and clarification of clinical and anamnestic data. Unfortunately, it is a fact that preference is given to laboratory methods for diagnosis based on specific IgE determination or skin samples. However, the basis for cause-significant allergen identifying is detecting detailed medical history and clinical picture of a disease which still appears to be the most reliable tool for FA diagnosis.

The role of ala198 in the stability and coenzyme specificity of bacterial formate dehydrogenases.

It has been shown by an X-ray structural analysis that the amino acid residues Ala198, which are located in the coenzyme-binding domain of NAD(+)-dependent formate dehydrogenases (EC 1.2.1.2., FDH) from bacteria Pseudomonas sp.101 and Moraxella sp. C-1 (PseFDH and MorFDH, respectively), have non-optimal values of the angles ψ and φ. These residues were replaced with Gly by site-directed mutagenesis. The mutants PseFDH A198G and MorFDH A198G were expressed in E.coli cells and obtained in active and soluble forms with more than 95% purity. The study of thermal inactivation kinetics showed that the mutation A198G results in a 2.5- fold increase in stability compared to one for the wild-type enzymes. Kinetic experiments indicate that A198G replacement reduces the KM (NAD+) value from 60 to 35 and from 80 to 45 µM for PseFDH and MorFDH, respectively, while the KM (HCOO-) value remains practically unchanged. Amino acid replacement A198G was also added to the mutant PseFDH D221S with the coenzyme specificity changed from NAD(+) to NADP(+). In this case, an increase in thermal stability was also observed, but the influence of the mutation on the kinetic parameters was opposite: KM increased from 190 to 280 µM and from 43 to 89 mM for NADP(+) and formate, respectively. According to the data obtained, inference could be drawn that earlier formate dehydrogenase from bacterium Pseudomonas sp. 101 was specific to NADP(+), but not to NAD(+).

Improvement of the soy formate dehydrogenase properties by rational design.

Previous experiments on substitution of the residue Phe290 to Asp, Asn and Ser in NAD(+)-dependent formate dehydrogenase from soya Glycine max (SoyFDH) showed important role of the residue in enzyme thermal stability and catalytic properties (Alekseeva et al. Prot. Eng. Des. Sel., 2012a; 25: :781-88). In this work, we continued site-directed mutagenesis experiments of the Phe290 and the residue was changed to Ala, Thr, Tyr, Glu and Gln. All amino acid changes resulted in increase of catalytic constant from 2.9 to 3.5-4.7 s(-1). The substitution Phe290Ala led to KM (NAD+) decrease from 13.3 to 8.6 µM, and substitutions Phe290Tyr and Phe290Glu resulted in decrease and increase of KM (HCOO-) from 1.5 to 0.9 and -2.9 mM, respectively. The highest improvement of catalytic properties was observed for SoyFDH Phe290Ala which showed 2-fold higher catalytic efficiency with both substrates. Stability of mutants was examined by study of thermal inactivation kinetics and differential scanning calorimetry (DSC). All five amino acids provided increase of thermal stability of mutant SoyFDH in comparison with wild-type enzyme. Mutant SoyFDH Phe290Glu showed the highest improvement-the stabilization effect was 43 at 56°C. The DSC data agree with results of thermal inactivation kinetics. Substitutions Phe290Tyr, Phe290Thr, Phe290Gln and Phe290Glu provided Tm value increase 0.6°-6.6°. SoyFDH Phe290Glu and previously prepared SoyFDH Phe290Asp show similar thermal stability as enzymes from Candida boidinii and Mycobacterium vaccae N10 and have higher catalytic efficiency with NAD(+) compared with all described FDHs. Therefore, these mutants are very perspective enzymes for coenzyme regeneration in processes of chiral synthesis with dehydrogenases.

[About Minimization of Expenses on Allergy Diagnosis in Children: Analysis of Consistency of in Vitro- and in Vivo-Allergic Examinations Results].

UNLABELLED: High morbidity rate of atopic diseases among children, including high importance of grass pollen as a sensitizing agent, determine the relevance ofstudies on diagnostic examination systems for appointment of adequate therapy. The research of the most relevant allergens for patients to excludeof duplicating and uninformative tests became urgent after development of a new type of diagnostic tests that does not require expensive equipment. The objective of this research was to evaluate the results of in vitro- and in vivo-diagnostic examinations of children with various forms of atopic disease caused by pollen of meadow grasses, and to choose the most significant prognostic parameters for the diagnosis. METHODS: 277 children aged 4-16 years with various forms of atopic disease were included in the study. There were performed skin prick tests and determination of IgE-antibodies levels to allergen extracts of cocksfoot (g3), meadow fescue (g4), timothy grass (g6). RESULTS: In the studied group of patients 32-50% of children have antibodies to grass allergens. There was a close correlation of antibody response on the investigated allergens, quantitative coincidence of IgE-antibodies to g3 andg4 allergens levels. IgE (g6) concentration was close to the IgE(g3) and IgE(g4) levels (85.0 ± 21.6%). Analysis of the skin tests results showed that 44% of patients have a positive response to grass allergens, and in vivo-tests results coincide with serologicaltests results, mostly in a qualitative sense. The most significant relationship was noted between in vivo and in vitro-tests in the results of testing the response to meadow fescue pollen. CONCLUSION: Based on these data IgE concentration index to meadow fescue allergens can be used as a prognostic marker to determine the sensitization of patients with different nosology forms of allergy and can help to improve allergic diagnostics.

Role of a Structurally Equivalent Phenylalanine Residue in Catalysis and Thermal Stability of Formate Dehydrogenases from Different Sources.

Comparison of amino acid sequences of NAD+-dependent formate dehydrogenases (FDH, EC 1.2.1.2) from different sources and analysis of structures of holo-forms of FDH from bacterium Pseudomonas sp. 101 (PseFDH) and soya Glycine max (SoyFDH) as well as of structure of apo-form of FDH from yeast Candida boidinii (CboFDH) revealed the presence on the surface of protein globule of hydrophobic Phe residue in structurally equivalent position (SEP). The residue is placed in the coenzyme-binding domain and protects bound NAD+ from solvent. The effects of amino acid changes of the SEP on catalytic properties and thermal stability of PseFDH, SoyFDH, and CboFDH were compared. The strongest effect was observed for SoyFDH. All eight amino acid replacements resulted in increase in thermal stability, and in seven cases, increase in catalytic constant was achieved. Thermal stability of SoyFDH after mutations Phe290Asp and Phe290Glu increased 66- and 55-fold, respectively. KM values of the enzyme for substrate and coenzyme in different cases slightly increased or decreased. In case of one CboFDH, the mutein catalytic constant increased and thermal stability did not changed. In case of the second CboFDH mutant, results were the opposite. In one PseFDH mutant, amino acid change did not influence the catalytic constant, but in three others, the parameter was reduced. Two PseFDH mutants had higher and two mutants lower thermal stability in comparison with initial enzyme. Analysis of results of SEP mutagenesis in FDHs from bacterium, yeast, and plant shows that protein structure plays a key role for effect of the same amino acid changes in equivalent position in protein globule of formate dehydrogenases from different sources.

Efficacy and safety of pidotimod in the prevention of recurrent respiratory infections in children: a multicentre study.

Acute respiratory infections (ARI) still represent a big challenge for paediatricians, especially in those children defined as "ailed" as they are more susceptible to such kinds of disease. In this paediatric population, the immune system is still under-developed with an evident alteration in cytokine levels. A clinical study was carried out in 5 sites in Russia with the intention to enroll children particularly susceptible to contract respiratory infections (defined as "ailing"), assigning them to a treatment group with pidotimod in comparison with a control group, treating them for 30 days and observing the reduction in the number of ARI episodes throughout the follow-up period (6 months). Moreover, changes in serum immunological markers were evaluated at baseline and 30 days after treatment discontinuation. One hundred and fifty-seven ailing children were enrolled and assigned to two arms: a main pidotimod treatment group or a control group. The percentage of incidence of ARIs in the observation period at three different time points was statistically significant (p < 0.05). At the end of the follow-up period (after 6 months), ARIs had developed in 72 children (92.3%) in the main group and in 79 patients (100%) in the control group. Concerning changes of the immunological markers, the treatment group showed a better profile of normalization compared to the control group. The 30-day pidotimod therapy course led to improvement/reduction in the rate of acute respiratory infection recurrence in ailing children within a 3-month period, with a quick elimination of symptoms and signs of infection and, as a result, a faster recovery. The normalisation of the content of the pro-inflammatory cytokine interleukin-8 confirmed the immune-modulatory effect of the investigational drug, underlying its prophylactic effect.

Stabilization of plant formate dehydrogenase by rational design.

Recombinant formate dehydrogenase (FDH, EC 1.2.1.2) from soy Glycine max (SoyFDH) has the lowest values of Michaelis constants for formate and NAD+ among all studied formate dehydrogenases from different sources. Nevertheless, it also has the lower thermal stability compared to enzymes from bacteria and yeasts. The alignment of full sequences of FDHs from different sources as well as structure of apo- and holo-forms of SoyFDH has been analyzed. Ten mutant forms of SoyFDH were obtained by site-directed mutagenesis. All of them were purified to homogeneity and their thermal stability and substrate specificity were studied. Thermal stability was investigated by studying the inactivation kinetics at different temperatures and by differential scanning calorimetry (DSC). As a result, single-point (Ala267Met) and double mutants (Ala267Met/Ile272Val) were found to be more stable than the wild-type enzyme at high temperatures. The stabilization effect depends on temperature, and at 52°C it was 3.6- and 11-fold, respectively. These mutants also showed higher melting temperatures in DSC experiments - the differences in maxima of the melting curves (T(m)) for the single and double mutants were 2.7 and 4.6°C, respectively. For mutations Leu24Asp and Val127Arg, the thermal stability at 52°C decreased 5- and 2.5-fold, respectively, and the T(m) decreased by 3.5 and 1.7°C, respectively. There were no differences in thermal stability of six mutant forms of SoyFDH - Gly18Ala, Lys23Thr, Lys109Pro, Asn247Glu, Val281Ile, and Ser354Pro. Analysis of kinetic data showed that for the enzymes with mutations Val127Arg and Ala267Met the catalytic efficiency increased 1.7- and 2.3-fold, respectively.

NAD (+) -dependent Formate Dehydrogenase from Plants.

NAD(+)-dependent formate dehydrogenase (FDH, EC 1.2.1.2) widely occurs in nature. FDH consists of two identical subunits and contains neither prosthetic groups nor metal ions. This type of FDH was found in different microorganisms (including pathogenic ones), such as bacteria, yeasts, fungi, and plants. As opposed to microbiological FDHs functioning in cytoplasm, plant FDHs localize in mitochondria. Formate dehydrogenase activity was first discovered as early as in 1921 in plant; however, until the past decade FDHs from plants had been considerably less studied than the enzymes from microorganisms. This review summarizes the recent results on studying the physiological role, properties, structure, and protein engineering of plant formate dehydrogenases.

[A comparative study of the thermal stability of formate dehydrogenases from microorganisms and plants].

A comparative study of the thermostability of NAD+-dependent formate dehydrogenases (FDHs; EC 1.2.1.2) from both methylotrophic bacteria Pseudomonas sp. 101 and Moraxella sp. Cl, the methane-utilizing yeast Candida boidinii, and plants Arabidopsis thaliana and Glycine max (soybean) was performed. All the enzymes studied were produced by expression in E. coli cells. The enzymes were irreversibly inactivated in one stage according to first-order reaction kinetics. The FDH from Pseudomonas sp. 101 appeared as the most thermostable enzyme; its counterpart from G. max exhibited the lowest stability. The enzymes from Moraxella sp. Cl, C. boidinii, and A. thaliana showed similar thermostability profiles. The temperature dependence of the inactivation rate constant of A. thaliana FDH was studied. The data of differential scanning calorimetry was complied with the experimental results on the inactivation kinetics of these enzymes. Values of the melting heat were determined for all the enzymes studied.