[Diabetic gastroenteropathy: modern methods of diagnosis and treatment].

Diabetes mellitus is a chronic disease with a growing prevalence worldwide, however, the prevalence of its complications, including gastroenteropathy, is also increasing. The pathophysiology of diabetic gastroenteropathy (DH) combines hyperglycemia, vagus nerve dysfunction, decreased expression of nitric oxide synthase in the myenteric plexus, changes in the interstitial Cajal cell network, as well as oxidative stress. Clinical signs of DH are gastroesophageal reflux, gastroparesis, constipation, abdominal pain and diarrhea. Among the diagnostic methods are manometry with pH measurement (assessment of esophageal motility), gastric emptying scintigraphy, respiratory test (to assess gastroparesis), aspiration and cultivation of the contents of the jejunum (to diagnose bacterial overgrowth syndrome). To date, there is no definitive treatment for DH - an interdisciplinary approach is aimed at slowing the progression of the disease, relieving symptoms and restoring gastrointestinal function. Patients are recommended a diet low in simple sugars and high in fiber; optimization of glycemic control with a target glycemia of less than 180 mg/dl. As for drug therapy, the use of prokinetics and antiemetics is justified, and in case of excessive bacterial growth syndrome, antibacterial therapy (rifaximin) is carried out. Modern approaches to the treatment of DH are also accumulating, including the use of botulinum toxin, pyloroplasty and electrical stimulation of the stomach in individual patients. Despite the constant development of new treatments, they are not yet able to completely cure DH in the near future, which makes it necessary to conduct further research in this area.

N-Terminal Fragment of Brain-Type Natriuretic Peptide (NT-proBNP) as a Prognostic Marker in Patients with Newly Diagnosed Multiple Myeloma Complicated by Dialysis-Dependent Renal Failure.

Prognostic value of N-terminal fragment of the prohormone brain-type natriuretic peptide (NT-proBNP) was analyzed in patients with multiple myeloma complicated by dialysisdependent renal failure. The prospective study included 20 patients with newly diagnosed multiple myeloma. The concentrations of NT-proBNP were measured before antimyeloma chemotherapy. The median age of the patients was 67 (63-76) years. The median glomerular filtration rate was 4 (4, 5) ml/min/1.73 m2. For overall survival, the area under ROC curve was 0.75 and the cut-off point was 7000 pg/ml. At median follow-up of 17.3 months, the overall survival was 76.6±14.8 and 27.3±13.4% (p=0.02) for cases with NT-proBNP levels below and above the cut-off point, respectively. There were no cases of death due to cardiovascular causes. We concluded that the increase in serum concentration of NT-proBNP>7400 pg/ml is associated with the severity of kidney damage and the risk of non-cardiac mortality.

[CLINICAL AND EPIDEMIOLOGICAL CHARACTERISTICS OF MYELODYSPLASTIC SYNDROMES IN ADULTS].

The myelodysplastic syndromes (MDS) are a distinct group of clonal disorders of hematopoietic stem or progenitor cells characterized by ineffective hematopoiesis and peripheral cytopenias. The data on the epidemiology of MDS in Russia are absent.The aim of the study was to evaluate the incidence of MDS in adults, to evaluate methods of diagnosis confirmation and choice of therapy in the system of Moscow Health Care.The observational study included adult patients with newly diagnosed MDS in 2010. Two hundred and one adult patients (male - 110, female - 118) were registered. Median age at diagnosis was 71.5 years (range, 23.9-93.7). The incidence rate of MDS was 2.0 cases per 100.000 persons per year in the general adult population. All patients divided into 5 groups depending on the type of first-line therapy: 69 patients treated withepoetin alfa or beta; 20 - lowdose Ara-C; 12 - hypomethylating agents; 60 - symptomatic (red cell transfusion for low-risk MDS) and 38 - palliative care (elderly and weakened high-risk patients). Two patients with 5q- syndrome treated with lenalidomide. With a median follow-up for survivors 46 months 4-year overall survival (OS) for all patients was 34.8±13.4% (median 24.3 months). The incidence of MDS in Moscow, Russia is 1.5-2 times lower than in Europe and the United States. Current standards of survey under the mandatory health insurance does not provide for molecular and cytogenetic assays, which is one of the factors limiting the diagnostic potential.

[Clinical and epidemiological characteristics of acute myeloid leukemias in adults according to the data of municipal hematology departments in Moscow].

AIM: To estimate the incidence of acute myeloid leukemias (AML) in Moscow adults and to evaluate the efficiency of their treatment. SUBJECTS AND METHODS: Data on Moscow residents who were first diagnosed with AML in 2010 were retrospectively collected. The efficiency of their treatment was evaluated from the rates of complete remissions (CR), recurrences, deaths, and 4-year overall (OS) and relapse-free survival (RFS). The data as of September 1, 2013, were analyzed. RESULTS: According to the 2010 pooled materials of the city's municipal hematology departments, AML (non-M3 types) was diagnosed in 286 patients whose median age at diagnosis was 64.9 years (range, 18.2-92.0 years). The notified incidence rate was 2.9 (3.3 for men and 2.6 for women) cases per 100,000 population. 118 (41%) patients received intensive chemotherapy (ICT); 119 (42%) had chemotherapy with low-dose cytarabine (LDC); 7 (2%) had that with hypomethylating agents (HA); and 42 (15%) had palliative therapy (PT). During first-line therapy, none of the patients underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT). In the entire group, the early (within the first 60 days) mortality rates were 42% (119 deaths); that of patients with primary refractory disease was 32% (90 deaths). CR was achieved in 77 (27%) patients: 57 (48%) on ICT, 17 (14%) on LDC, and 3 (43%) on HA. Recurrences occurred in 37 (48%) of the 77 patients who had achieved CR at a median follow-up of 43.9 months. Four-year OS in all the patients receiving PT was 9.8±1.9% (18.2±3.9% in the patients on ICT versus 4.5±2% in those of LDC; p=0.028); 4-year RFS was 36.1±5.7% (39.6±6.7% inthe patients on ICT versus 31.3±11 .6% in those on LDC; p=0.8). CONCLUSION: High mortality rates in the induction, which are caused by the limited resources of accompanying therapy, poor sanitary conditions, and no own opportunities to perform allo-HSCT, remain a key problem of AML therapy in adults.

[Experience with high-dose chemotherapy in patients with testicular diffuse large B-cell lymphoma].

AIM: To evaluate the efficiency of high-dose therapy according to the DLBL-CNS-2007 protocol in patients with testicular diffuse large B-cell lymphoma (DLBL). SUBJECTS AND METHODS: Out of 408 male patients with non-Hodgkin lymphoma, 8 patients aged 50 to 69 years (median age 55.5 years) with primary testicular (n=3) or with generalized-stage testicular DLBL (n=5) were included in the study. These patients were followed up at the Hematology Research Center, Ministry of Health of the Russian Federation, in 2007 to 2013. Systemic chemotherapy was performed in accordance with the DLBL-CNS-2007 protocol. RESULTS: The DLBL-CNS-2007 protocol was implemented in first-line therapy in 7 patients. At the first diagnostic stage, one patient was found to have anaplastic seminoma; in this connection right orchifuniculectomy was carried out, followed by radiotherapy applied to the scrotal region in a total focal dose of 34 Gy. This patient with disease recurrence was included in the DLBL-CNS-2007 treatment protocol. The number of polychemotherapy (PCT) cycles (n=4 or 6) was determined by the time to achieve complete remission. After completion of DLBL-CNS-2007 PCT, 6 patients achieved complete remission; the primary resistant disease was noted in 2 cases. At this moment 6 patients are alive in first complete remission during the median follow-up of 50 months (10-54 months). CONCLUSION: The findings suggest that high-dose therapy according to the DLBL-CNS-2007 protocol in patients with testicular DLBL can achieve complete remission and increase overall and event-free survival rates. This fact should be borne out by a large number of observations.

Crystal structure of the CheA histidine phosphotransfer domain that mediates response regulator phosphorylation in bacterial chemotaxis.

The x-ray crystal structure of the P1 or H domain of the Salmonella CheA protein has been solved at 2.1-A resolution. The structure is composed of an up-down up-down four-helix bundle that is typical of histidine phosphotransfer or HPt domains such as Escherichia coli ArcB(C) and Saccharomyces cerevisiae Ypd1. Loop regions and additional structural features distinguish all three proteins. The CheA domain has an additional C-terminal helix that lies over the surface formed by the C and D helices. The phosphoaccepting His-48 is located at a solvent-exposed position in the middle of the B helix where it is surrounded by several residues that are characteristic of other HPt domains. Mutagenesis studies indicate that conserved glutamate and lysine residues that are part of a hydrogen-bond network with His-48 are essential for the ATP-dependent phosphorylation reaction but not for the phosphotransfer reaction with CheY. These results suggest that the CheA-P1 domain may serve as a good model for understanding the general function of HPt domains in complex two-component phosphorelay systems.

Carboxyl methylation regulates phosphoprotein phosphatase 2A by controlling the association of regulatory B subunits.

Phosphoprotein phosphatase 2A (PP2A) is a major phosphoserine/threonine protein phosphatase in all eukaryotes. It has been isolated as a heterotrimeric holoenzyme composed of a 65 kDa A subunit, which serves as a scaffold for the association of the 36 kDa catalytic C subunit, and a variety of B subunits that control phosphatase specificity. The C subunit is reversibly methyl esterified by specific methyltransferase and methylesterase enzymes at a completely conserved C-terminal leucine residue. Here we show that methylation plays an essential role in promoting PP2A holoenzyme assembly and that demethylation has an opposing effect. Changes in methylation indirectly regulate PP2A phosphatase activity by controlling the binding of regulatory B subunits to AC dimers.

Carboxyl methylation of the phosphoprotein phosphatase 2A catalytic subunit promotes its functional association with regulatory subunits in vivo.

The phosphoprotein phosphatase 2A (PP2A) catalytic subunit contains a methyl ester on its C-terminus, which in mammalian cells is added by a specific carboxyl methyltransferase and removed by a specific carboxyl methylesterase. We have identified genes in yeast that show significant homology to human carboxyl methyltransferase and methylesterase. Extracts of wild-type yeast cells contain carboxyl methyltransferase activity, while extracts of strains deleted for one of the methyltransferase genes, PPM1, lack all activity. Mutation of PPM1 partially disrupts the PP2A holoenzyme in vivo and ppm1 mutations exhibit synthetic lethality with mutations in genes encoding the B or B' regulatory subunit. Inactivation of PPM1 or overexpression of PPE1, the yeast gene homologous to bovine methylesterase, yields phenotypes similar to those observed after inactivation of either regulatory subunit. These phenotypes can be reversed by overexpression of the B regulatory subunit. These results demonstrate that Ppm1 is the sole PP2A methyltransferase in yeast and that its activity is required for the integrity of the PP2A holoenzyme.

Kinetics of CheY phosphorylation by small molecule phosphodonors.

The chemotaxis response regulator CheY can acquire phosphoryl groups either from its associated autophosphorylating protein kinase, CheA, or from small phosphodonor molecules such as acetyl phosphate. We report a stopped-flow kinetic analysis of CheY phosphorylation by acetyl phosphate. The results show that CheY has a very low affinity for this phosphodonor (K(s)&z.Gt;0.1 M), consistent with the conclusion that, whereas CheY provides catalytic functions for the phosphotransfer reaction, the CheA kinase may act simply to increase the effective phosphodonor concentration at the CheY active site.

A specific protein carboxyl methylesterase that demethylates phosphoprotein phosphatase 2A in bovine brain.

Phosphoprotein phosphatase 2A (PP2A) is one of the four major protein serine/threonine phosphatases found in all eukaryotic cells. We have shown that the 36-kDa catalytic subunit of PP2A is carboxyl methylated in eukaryotic cells, and we have previously identified and purified a novel methyltransferase (MTase) that is responsible for this modification. Here, we describe a novel protein carboxyl methyl-esterase (MEase) from bovine brain that demethylates PP2A. The enzyme has been purified to homogeneity as a monomeric 46-kDa soluble protein. The MEase is highly specific for PP2A. It does not catalyze the demethylation of other protein or peptide methylesters. Moreover, MEase activity is dramatically inhibited by nanomolar concentrations of okadaic acid, a specific inhibitor of PP2A. From these results, we conclude that PP2A methylation is controlled by two specific enzymes, a MTase and a MEase. Since PP2A methylation is highly conserved in eukaryotes ranging from human to yeast, it is likely that this system plays an important role in phosphatase regulation.