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Mikhail Y Ledyaev, Olga V Stepanova, Anastasia M Ledyaeva Department of Pediatric Disease, Volgograd State Medical University, Volgograd, Russian Federation Background: Automatic 24-hour ambulatory blood pressure (BP) monitoring (ABPM) is a basic procedure performed in adults with arterial hypertension, but ABPM monitors have become widely used in pediatric practice only recently. The main problem is the lack of common normative data sets for ABPM in children and the small number of appropriate monitors that can be used for analysis of the 24-hour BP profile in this age group. The aim of this study was to validate the BPLab® ABPM monitor according to the 1993 British Hypertension Society (BHS-93) protocol, as well as to work out solutions regarding the feasibility of this device in pediatric practice. Methods: Our study included 30 children of both sexes and aged 5–15 years, ie, “older” children according to the BHS-93 protocol. Before starting the study, we obtained ethical approval from the regional scientific ethics committee. All participants and their parents signed their written consent for participation in the study. The data were simultaneously obtained by three experts, who had completed a noninvasive BP measurement training course. BP values were measured using the Korotkoff auscultatory method (Phase I for systolic BP and Phase V for diastolic BP). Discrepancies in the systolic and diastolic BP measurements (n=180; 90 for each expert) were analyzed according to the criteria specified in the BHS-93 protocol. Results: The device was graded “A” for both systolic BP and diastolic BP according to the criteria of the BHS-93 protocol. Conclusion: The BPLab ABPM device may be recommended for extensive pediatric use. Keywords: ambulatory blood pressure monitoring, children, device, validation&nbsp

Kinase-related protein (KRP) and caldesmon are abundant myosin-binding proteins of smooth muscle. KRP induces the assembly of unphosphorylated smooth muscle myosin filaments in the presence of ATP by promoting the unfolded state of myosin. Based upon electron microscopy data, it was suggested that caldesmon also possessed a KRP-like activity (Katayama et al., 1995, J Biol Chem 270: 3919–3925). However, the nature of its activity remains obscure since caldesmon does not affect the equilibrium between the folded and unfolded state of myosin. Therefore, to gain some insight into this problem we compared the effects of KRP and caldesmon, separately, and together on myosin filaments using turbidity measurements, protein sedimentation and electron microscopy. Turbidity assays demonstrated that KRP reduced myosin filament aggregation, while caldesmon had no effect. Additionally, neither caldesmon nor its N-terminal myosin binding domain (N152) induced myosin polymerization at subthreshold Mg2+ concentrations in the presence of ATP, whereas the filament promoting action of KRP was enhanced by Mg2+. Moreover, the amino-terminal myosin binding fragment of caldesmon, like the whole protein, antagonizes Mg2+-induced myosin filament formation. In electron microscopy experiments, caldesmon shortened myosin filaments in the presence of Mg2+ and KRP, but N152 failed to change their appearance from control. Therefore, the primary distinction between caldesmon and KRP appears to be that caldesmon interacts with myosin to limit filament extension, while KRP induces filament propagation into defined polymers. Transfection of tagged-KRP into fibroblasts and overlay of fibroblast cytoskeletons with Cy3KRP demonstrated that KRP colocalizes with myosin structures in vivo. We propose a new model that through their independent binding to myosin and differential effects on myosin dynamics, caldesmon and KRP can, in concert, control the length and polymerization state of myosin filaments.

The nonmuscle/smooth muscle myosin light chain kinase (MLCK) and the kinase related protein (KRP) that lacks protein kinase activity are myosin II binding proteins encoded in the vertebrate genome by a true gene within a gene relationship. The genomic organization and expression result in the same amino acid sequence in different molecular contexts from two different sizes of mRNA. We report here the identification and characterization of a third size class of gene products. The protein appears to be a higher molecular weight form of MLCK with additional amino terminal tail sequence which might provide differential subcellular targeting characteristics.

The exertion of periodic dynamic strain on the arterial wall is hypothesized to be relevant to smooth muscle cell morphology and function. This study has investigated the effect of cyclic mechanical stretching on rabbit aortic smooth muscle cell proliferation and expression of contractile phenotype protein markers. Cells were cultured on flexible-bottomed dishes and cyclic stretch was applied (frequency 30 cycles/min, 15% elongation) using a Flexercell Strain unit. Cyclic stretch potentiated smooth muscle cell proliferation in serum-activated cultures but not in cultures maintained in 0.5% fetal calf serum. Stretching induced a serum-independent increase of h-caldesmon expression and this effect was reversible following termination of mechanical stimulation. Strain was without effect on smooth muscle myosin or calponin expression. In cells grown on laminin stretch-induced h-caldesmon expression was more prominent than in cells cultured on collagen types I and IV, poly-L-lysine and gelatin. These data suggest that cyclic mechanical stimulation possesses dual effect on vascular smooth muscle cell phenotype characteristics since it: 1) potentiates proliferation, an attribute of a dedifferentiated phenotype; and 2) increases expression of h-caldesmon considered a marker of a differentiated smooth muscle cell state.

Recently discovered 210-kDa myosin light chain kinase (MLCK-210) is identical to 108-130 kDa MLCK, the principal regulator of the myosin II molecular motor, except for the presence of a unique amino terminal extension. Our in vitro experiments and transfected cell studies demonstrate that the N-terminal half of MLCK-210 unique tail domain has novel microfilament and microtubule binding activity. Consistent with this activity, the MLCK-210 domain codistributes with microfilaments and microtubules in cultured cells and with soluble tubulin in nocodazole-treated cells. This domain is capable of aggregating tubulin dimers in vitro, causing bundling and branching of microtubules induced by taxol. The N-terminal actin-binding region of MLCK-210 has lower affinity to actin (K(d) = 7.4 microM) than its central D(F/V)RXXL repeat-based actin-binding site and does not protect stress fibers from disassembly triggered by MLCK inhibition in transfected cells. Obtained results suggest that while being resident on microfilaments, MLCK-210 may interact with other cytoskeletal components through its N-terminal domain. Based on available evidence, we propose a model in which MLCK-210 could organize cell motility by simultaneous control of cytoskeleton architecture and actomyosin activation through the novel protein scaffold function of the unique tail domain and the classical MLCK catalytic function of the kinase domain.

Kinase-related protein (KRP) and caldesmon are abundant myosin-binding proteins of smooth muscle. KRP induces the assembly of unphosphorylated smooth muscle myosin filaments in the presence of ATP by promoting the unfolded state of myosin. Based upon electron microscopy data, it was suggested that caldesmon also possessed a KRP-like activity (Katayama et al., 1995, J Biol Chem 270: 3919-3925). However, the nature of its activity remains obscure since caldesmon does not affect the equilibrium between the folded and unfolded state of myosin. Therefore, to gain some insight into this problem we compared the effects of KRP and caldesmon, separately, and together on myosin filaments using turbidity measurements, protein sedimentation and electron microscopy. Turbidity assays demonstrated that KRP reduced myosin filament aggregation, while caldesmon had no effect. Additionally, neither caldesmon nor its N-terminal myosin binding domain (N152) induced myosin polymerization at subthreshold Mg2+ concentrations in the presence of ATP, whereas the filament promoting action of KRP was enhanced by Mg2+. Moreover, the amino-terminal myosin binding fragment of caldesmon, like the whole protein, antagonizes Mg(2+)-induced myosin filament formation. In electron microscopy experiments, caldesmon shortened myosin filaments in the presence of Mg2+ and KRP, but N152 failed to change their appearance from control. Therefore, the primary distinction between caldesmon and KRP appears to be that caldesmon interacts with myosin to limit filament extension, while KRP induces filament propagation into defined polymers. Transfection of tagged-KRP into fibroblasts and overlay of fibroblast cytoskeletons with Cy3KRP demonstrated that KRP colocalizes with myosin structures in vivo. We propose a new model that through their independent binding to myosin and differential effects on myosin dynamics, caldesmon and KRP can, in concert, control the length and polymerization state of myosin filaments.

The results of mathematical simulation of conjugate heat transfer for heat supply object are represented. The turbulent regime of air motion in a closed cavity with the enclosing walls from reinforced concrete and glass is examined. On the outer boundary, which includes window aperture, the conditions of convective-radiation heat exchange with environment are realized. Is solved the system of the dimensionless equations within the framework of thermal conductivity model for the solid walls and Navier-Stokes for the gas. The influence of the local zones of intensive heat transfer on the thermal regime of the heat supply objects is established. Are determined the values of the dimensionless heat exchange coefficient on division border “air - wall”. The analysis of the values of mean temperatures of the solution region is carried out.