Influence of Surfactant Structure on Polydisperse Formulations of Alkyl Ether Sulfates and Alkyl Amidopropyl Betaines

Surfactants provide detergency, foaming, and texture in personal care formulations, yet the micellization of typical industrial primary and cosurfactants is not well understood, particularly in light of the polydisperse nature of commercial surfactants. Synergistic interactions are hypothesized to drive the formation of elongated wormlike self-assemblies in these mixed surfactant systems. Small-angle neutron scattering, rheology, and pendant drop tensiometry are used to examine surface adsorption, viscoelasticity, and self-assembly structure for wormlike micellar formulations comprising cocoamidopropyl betaine, and its two major components laurylamidopropyl betaine and oleylamidopropyl betaine, with sodium alkyl ethoxy sulfates. The tail length of sodium alkyl ethoxy sulfates was related to their ability to form wormlike micelles in electrolyte solutions, indicating that a tail length greater than 10 carbons is required to form wormlike micelles in NaCl solutions, with the decyl homologue unable to form elongated micelles and maintaining a low viscosity even at 20 wt % surfactant loading with 4 wt % NaCl present. For these systems, the incorporation of a disperse ethoxylate linker does not enable shorter chain surfactants to elongate into wormlike micelles for single-component systems; however, it could increase the interactions between surfactants in mixed surfactant systems. For synergy in surfactant mixing, the nonideal regular solution theory is used to study the sulfate/betaine mixtures. Tail mismatch appears to drive lower critical micelle concentrations, although tail matching improves synergy with larger relative reductions in critical micelle concentrations and greater micelle elongation, as seen by both tensiometric and scattering measurements.

Structure-Performance Relationships for Tail Substituted Zwitterionic Betaine-Azobenzene Surfactants

Azobenzene-containing surfactants (azo-surfactants) have garnered significant attention for their use in generating photoresponsive foams, interfaces, and colloidal systems. The photoresponsive behavior of azo-surfactants is driven by the conformational and electronic changes that occur when the azobenzene chromophore undergoes light-induced trans ⇌ cis isomerization. Effective design of surfactants and targeting of their properties requires a robust understanding of how the azobenzene functionality interacts with surfactant structure and influences overall surfactant behavior. Herein, a library of tail substituted azo-surfactants were synthesized and studied to better understand how surfactant structure can be tailored to exploit the azobenzene photoswitch. This work shows that tail group structure (length and branching) has a profound influence on the critical micelle concentration of azo-surfactants and their properties once adsorbed to an air-water interface. Neutron scattering studies revealed the unique role that intermolecular π-π azobenzene interactions have on the self-assembly of azo-surfactants, and how the influence of these interactions can be tuned using tail group structure to target specific aqueous aggregate morphologies.

In Situ Nanostructural Analysis of Concentrated Wormlike Micellar Fluids Comprising Sodium Laureth Sulfate and Cocamidopropyl Betaine Using Small-Angle Neutron Scattering

Concentrated wormlike micellar fluids form the basis for a vast array of formulated products, from liquid soaps and shampoos to drag reduction and drilling fluids. Typically, these systems are analyzed using bulk rheological measurements to determine their flow properties and cryo-microscopy to detect their nanostructure. Small-angle neutron scattering provides an opportunity to directly and nonperturbatively analyze nanostructure in situ but is complicated for concentrated systems by correlations from interparticle volume exclusion. Here, we use small-angle and ultra-small-angle neutron scattering to probe directly for the first time the nanostructure of concentrated wormlike micellar fluids composed of the widely used surfactant pair sodium laureth sulfate and cocamidopropyl betaine in aqueous electrolytes. Obtained data are analyzed using different approaches to determine scattering contributions from the wormlike particles themselves and interactions between them. It is found that approximating worms as locally rigid cylinders offers some insight into their aggregation dimensions at short length scales, and both volume exclusion and screened Coulombic interaction potentials describe interactions reasonably well. Using the semi-empirical polymer reference interaction site model (PRISM) gives excellent agreement with observed scattering, and physical insight obtained using this approach is discussed in detail. A drawback of this method is the significant complexity in coding the model in order to fit data, so to facilitate this for future researchers, we provide with this paper a fully operational, open-source code to utilize this model.

Rehabilitation of patients with cerebral palsy using hand exoskeleton controlled by brain-computer interface

Cerebral palsy (CP) is one of the most severe central nervous system diseases in childhood associated with motor impairment. The study was aimed to assess the efficiency of the complex comprising brain-computer interface (BCI) and hand exoskeleton as an instrument for the motor function recovery in patients with CP complementing the essential therapy. The Fugl-Meyer Assessment scale, ARAT test and Jebsen–Taylor function test were used in 14 children and adolescents for the motor function improvement assessment after the therapy complemented by 7–10 BCI-exoskeleton based procedures. The EEG mu-rhythm sources properties during the motor imagery BCI control were studied. After the procedures completion, the significant improvement of the Fugl-Meyer Assessment scale score (7 (2; 11) for hand active movements; 4.5 (1; 6) for proximal arm and 2.5 (0; 5) for hand), ARAT test score (7.5 (1; 31) for total score, 1.5 (0; 12) for grasp movement and 1.5 (0; 8) for grip movement), as well as significantly different from the zero execution time reduction in three out of seven Jabsen–Taylor function test items (–1 (–4.13; 0.25) for simulated feeding; –1 (–2; 0) for moving light and heavy cans) were identified. The average BCI detection level was 0.51 (0.45; 0.54) (max = 0.70). In most EEG recordings the mu-rhythm sources were detected, both for intact and affected hemispheres. The mu-rhythm desynchronization associated with motor imagery was observed, significantly affecting the BCI accuracy. The results obtained indicate that the use of BCI-exoskeleton complex effectively complements the standard rehabilitation methods for children with CP, and suggest that its clinical effectiveness in individuals with CP may be proven by enrollment of more patients.

Analysis of the effect of pneumonia on mortality (ORACLE-RF)

Objective — To analyze the effect of pneumonia on mortality among patients with circulatory decompensation. Material and methods — The study was based on the ORACLE-RF registry containing information obtained from 20 cities in Russia. Patients were monitored for one year. The research included men and women with symptoms of chronic heart failure during circulatory decompensation period. The patients' average age was 67±13 years. Final analysis included 2404 patients. Results — Hospital mortality was at 9%. By the 30th day of observation, overall mortality rate stood at 13%. Within the year, the overall mortality rate was 43%. Pneumonia and chronic kidney disease (CKD) had the most pronounced effect on death risk – 49.5% and 47.2%. The study showed that patients who do not have pneumonia and CKD among other associated diseases were 2.5 times more likely to survive after 360 days of observation than patients who have them among other associated diseases. The chances of favorable prognosis in patients without pneumonia are 1.7 times higher than in patients with pneumonia among other diseases. Conclusion — Pneumonia probably triggered the decompensation mechanism and significantly increased mortality in these patients.

[Risk Assessment of Development of the Major Adverse Cardiac Events in Patients with Chronic Heart Failure with a Preserved and Intermediate Ejection Fraction in the Presence of a Bendopnea Symptom]

Aim To evaluate the risk of major cardiovascular complications (CVC) in patients with chronic heart failure (CHF) with intermediate and preserved ejection fraction (EF) depending on the presence of bendopnea symptom.Material and methods The study included 104 patients with stage II CHF and left ventricular EF ≥40 %. Mean age of the patients was 72.8±10.6 years. A test for detection of bendopnea symptom was performed for all patients. Two groups were formed: group 1, 69 patients with the bendopnea symptom and group 2, 35 patients with a negative test. Follow-up duration was 24 months. The composite endpoint (CEP) was death and hospitalization for any CVC.Results Mean time to the bendopnea symptom was 17.3±6.61 s. At two years of follow-up, the CEP was observed in 36 (34.6 %) patients, including 30 (43.5 %) patients in group 1 and 6 (17.1 %) patients in group 2. 12 patients died, and 9 of them had the bendopnea symptom. 21 patients of group 1 were hospitalized for CVC. Risk of CEP was significantly 1.7 times higher for men (relative risk, RR 1.7 [1.1; 2.6]) than for women. The presence of bendopnea symptom increased the risk of CEP 1.4 times (ОР 1.4 [1.1;1.9]) for women and 2.3 times (RR 2.3 [1.4; 3.6]) for men.Conclusion Results of the study demonstrated an unfavorable effect of bendopnea symptom on risk of CEP during the two-year follow-up of CHF patients with preserved and intermediate EF.

[Quality of life in patients with heart failure with preserved ejection fraction and the bendopnea symptom]

PURPOSE

The study of quality of life (QOL) in patients with CHF with preserved LVEF (left ventricular ejection fraction) and a symptom of bendopnea with different levels of salt intake. Materials and methods. The study included 66 patients. The main symptoms of CHF were edema in 54.5% of cases, dyspnea in 77% of cases, ascites was detected in only 2 patients, an enlarged liver in 7 patients. Abdominal obesity was detected in 53 patients. Quality of life was assessed by the SF‑36 questionnaire, the level of salt intake was assessed by the Charlton: SaltScreener questionnaire. Results. On average, the time of occurrence of the bendopnea was 22.5±9.3 seconds, the minimum was 5 seconds. The absence of the effect of abdominal obesity on the risk of bendopnea (relative risk 1.18 [0.76; 1.83]) was revealed. According to the SF‑36 questionnaire, a decrease in physical health indicators (median 31.3 points [20.7; 42.3]) and psychological health (average score 43.2±21.7) was found. In patients with bendopnea, QOL was reduced due to both physical and mental health, unlike patients without bendopnea: physical functioning (Physical Functioning - PF) 24.8±16.1 against 47±28.9 points, p=0.001 ; role‑based functioning due to physical condition (Role‑Physical Functioning - RP), 0 [0; 25] vs. 37.5 [0; 100] points, p=0.008; general health (General Health - GH) 29.9±15.8 against 50±14.2 points, p=0.0005, social functioning (Social Functioning - SF) 56 ± 38 against 78.9 ± 17.8 points ; p = 0.004. Multidimensional regression analysis revealed the relationship between the time of occurrence of the symptom bendopnea and the level of salt intake, physical and psychological activity (r2=0.25; p<0.009). The time of onset of the symptom of bendopnea in patients with CHF decompensation was significantly longer (18.9±8.7 vs. 26.2±8.5 seconds, p=0.003). The presence of diseases such as hypertension, COPD, IHD, atrial fibrillation, cerebrovascular disease did not significantly affect QOL (p> 0.05), while the presence of bronchial asthma or chronic kidney disease significantly reduced QOL of patients (p<0.05). Conclusion. The presence of the symptom bendopnea significantly reduces the quality of life of patients with CHF with preserved LVEF (left ventricular ejection fraction).

Energy-resolved neutron imaging options at a small angle neutron scattering instrument at the Australian Center for Neutron Scattering

Energy-resolved neutron imaging experiments conducted on the Small Angle Neutron Scattering (SANS) instrument, Bilby, demonstrate how the capabilities of this instrument can be enhanced by a relatively simple addition of a compact neutron counting detector. Together with possible SANS sample surveying and location of the region of interest, this instrument is attractive for many imaging applications. In particular, the combination of the cold spectrum of the neutron beam and its pulsed nature enables unique non-destructive studies of the internal structure for samples that are opaque to other more traditional techniques. In addition to conventional white beam neutron radiography, we conducted energy-resolved imaging experiments capable of resolving features related to microstructure in crystalline materials with a spatial resolution down to ∼0.1 mm. The optimized settings for the beamline configuration were determined for the imaging modality, where the compromise between the beam intensity and the achievable spatial resolution is of key concern.

Self-Assembly of Long-Chain Betaine Surfactants: Effect of Tailgroup Structure on Wormlike Micelle Formation

Long-chain amidopropyl betaines are known for their ability to self-assemble into viscoelastic wormlike micellar structures. Here, we explore the effect of tailgroup molecular architecture on this process, comparing five molecules, each with C18 chains but different levels of unsaturation and branching. The surfactants are synthesized from stearic, oleic, linoleic, linolenic, and isostearic acids. The self-assembly of these molecules in aqueous solutions is explored using small- and ultra-small-angle neutron scattering (SANS and USANS). It is seen that optimum wormlike micelle formation is achieved for the oleic-chained surfactant, and the alignment of self-assembled structures is further explored using rheo-SANS. The more highly unsaturated molecules form rodlike micelles, whereas the stearic-tailed molecule shows a pronounced Krafft point and the isostearic-chained surfactant is entirely water-insoluble. These results demonstrate the critical importance of tailgroup geometry on surfactant properties and self-assembly for this industrially important class of surfactants.

Bulk properties of aqueous graphene oxide and reduced graphene oxide with surfactants and polymers: adsorption and stability

Aqueous dispersions of graphene oxide and reduced graphene oxide are combined with carefully chosen surfactants and polymers to investigate adsorption and bulk properties in these systems.

[Correlations of IL-18 and IL-6 with sodium consumption in patients with arterial hypertension and diabetes mellitus]

AIM

To determine correlations of AH-associated interleukins (IL-18, IL-6) with sodium consumption in AH patients with and without DM.

MATERIALS AND METHODS

The study included AH patients with and without DM (n=63) who were managed at the Municipal Clinic #64, Moscow Department of Health Care, Branch 1. Plasma levels of IL-6 and IL-18 were measured using ELISA kits (Bender Med-Systems). Salt consumption was determined using a Charlton: SaltScreener questionnaire. Statistical analyses were performed using the Statistica 10.0 software.

RESULTS

Four groups were formed: Group 1, grade 2 AH and DM (n=19); Group 2, grade 2 AH and no DM (n=4); Group 3, grade 3 AH and no DM (n=28); and Group 4, grade 3 AH and DM (n=12). Group 2 was small and was excluded from further analysis due to impossibility of statistical treatment. All patients consumed more than 6 g of salt per day (approximately 10 g). Analysis of intergroup differences in selected parameters showed differences between groups in levels of cholesterol, triglycerides, LDL, and GFR. The following correlations were identified in the groups: Group 1, positive correlation of IL-18 with sodium consumption (r=0.65) and CRP level (r=0.52) and of IL-6 with LDL level (r=0.48); Group 3, positive correlation of IL-18 with IL-6 (r=0.66) and of IL-6 with CRP (r=0.52); Group 4, positive correlation of IL-18 with GFR (r=0.82) and of IL-6 with waist circumference (WC) (r=0.84) and IL-6 (r=0.73).

CONCLUSION

Patients consuming more than 6 g of salt daily (approximately 10 g) with AH and DM had more pronounced inflammation, which promoted progression of kidney disease.

[The effect of the level of total sodium deposited in the myocardium on its stiffness]

AIM

To determine a relationship between the level of total sodium in the myocardium to its stiffness.

SUBJECTS AND METHODS

The investigation enrolled 18 hypertensive patients who had suddenly died; their mean age was 40±10 years; mean waist circumference, 102±12.5 cm; height, 170±7.7 cm; myocardial mass, 319±53 g.

RESULTS

The variation in the myocardial level of total sodium averaged 211.7±37.5 (min, 71.5; max, 226.17) mmol/l. The sodium level was ascertained to be affected to the greatest extent by myocardial mass (SS=3615.56; p=0.00029) and age at death (SS=1965.568; p=0.0029), whereas gender and smoking had a considerably lower impact (SS=778.584; p=0.03). A univariate regression analysis showed that there was a relationship between myocardial sodium levels and the thickness of the anterior wall of the left ventricle (β=0.94; p=0.000001; r2=0.88), that of the anterior wall of the right ventricle (β=0.82; p=0.000021; r2=0.66), and that of the interventricular septum (β=0.94; p=0.000001; r2=0.89). The wall thickness of the myocardium was established to depend on its sodium level (SS=21813.89; p=0.000001; r2=0.88): the higher sodium amount in the myocardium, the thicker its walls. The average velocity of acoustic wave propagation was 6.24±0.51 m/sec. A significant correlation was observed between sodium concentrations in the myocardium and its stiffness (β=0.72; p=0.00062; r2=0.49).

CONCLUSION

The level of sodium deposited in the myocardium, which is directly related to dietary sodium intake, is significantly correlated with myocardial stiffness. It can be assumed that the elevated level of sodium deposited in the myocardium is an independent factor that changes the stiffness of the myocardium and appears to influence the development of its diastolic dysfunction.

[Impact of the dosing of basic drugs on the risk of rehospitalization in patients with chronic heart failure]

AIM

To investigate the impact of doses of the drugs, which have been achieved during adjustment and account for less or more than 50% of the maximal therapeutic ones on the risk of rehospitalization.

SUBJECTS AND METHODS

The data of the Pavlov Register were used to assess the treatment of patients with chronic heart failure. To assess the risk of rehospitalization in relation of the dose of a drug, all the doses were represented in percentage terms depending on the maximum therapeutic one.

RESULTS

The risk of hospitalization during 6 months in the patients receiving angiotensin-converting enzyme inhibitors at a dose of 25% or less of the therapeutic one was 21.18% (odds ratio (OR), 1.41; 95% confidence interval (CI), 1.13-1.76), that at doses of 50 and 100% of the therapeutic one was 16% (OR, 0.71; 95% CI, 0.56-0.88) and 34% (OR, 0.51; 95% CI, 0.43-0.60), respectively. The risk of rehospitalization in the patients taking β-blockers at doses of 25, 50, and 100% of the therapeutic one was 26% (OR, 1.05; 95% CI, 0.94-1.17), 23% (OR, 0.902; 95% CI, 0.75-1.07), and 6.25% (OR, 0.19; 95% CI, 0.07-0.56), respectively. The combined analysis of the dose and use frequency of diuretics showed that the highest risk of rehospitalization turned was noted in the patients using a single dose of 100 mg of furosemide (4.2% of cases) once weekly and was as high as 39% (OR, 0.45; 95% CI, 1.04-1.98).

CONCLUSION

The risk of rehospitalization is largely determined by the dosing factor in outpatient settings. Increasing the doses during adjustment reduces the risk of rehospitalization.

[WEAK COMBINED MAGNETIC FIELDS ADJUSTED TO THE PARAMETRIC RESONANCE FOR Ca2+ INTENSIFY DYSTROPHIN SYNTHESIS IN MDX MICE SKELETAL MUSCLES AFTER CELL THERAPY]

The mdx mice are an X-linked myopathic mutants, an animal model for human Duchenne muscular dystrophy (DMD). Mdx mice muscles are characterized by high level of striated muscle fibers (SMF) death followed by regeneration. As a result most SMFs of mdx mice have centrally located nuclei. The possibility of using stem cells therapy for the correction of DMD is actively being studied. One of the approaches to the usage of bone marrow stem cells for cellular therapy of DMD is the replacement of bone marrow after irradiation by X-rays. This method however does not give significant increase of dystrophin synthesis in mdx mice muscles fibers. We have tried to affect the mice after bone marrow transplantation by weak combined magnetic fields adjusted to the parametric resonance for Ca2+(Ca(2+)-MF) based on the data that the weak combined magnetic fields influence on tissues regeneration. We observed a significant increase in the proportion of dystrophin-positive SMFs in group of mdx mice radiation chimera 5 Gy and 3 Gy which was additionally exposed in Ca(2+)-MF in comparison with the control mdx mice and the group of mdx mice radiation chimera 5 Gy and 3 Gy which was kept in terrestrial magnetic field 2 months after chimera preparation--up to 15.8 and 18.3%, respectively. Also, there was an accumulation of SMFs without central nuclei. These data indicate a significanly increased efficacy of cell therapy in the case of additional exposition in Ca(2+)-MF. Thus, the efficiency of bone marrow transplantation mdx mice after both in doses 3 and 5 Gy was considerably enhanced by additional exposition to Ca(2+)-MF. Apparently, such magnetic field can intensify functioning of donor's nuclei which had been incorporated into muscle fibers.

DARA: a web server for rapid search of structural neighbours using solution small angle X-ray scattering data

Motivation: Small angle X-ray scattering (SAXS) is an established method for studying biological macromolecules in solution, whereby the experimental scattering patterns relate to the quaternary and tertiary structure of the macromolecule. Here we present DARA, a web-server, that queries over 150 000 scattering profiles pre-computed from the high resolution models of macromolecules and biological assemblies in the Protein Data Bank, to rapidly find nearest neighbours of a given experimental or theoretical SAXS pattern. Identification of the best scattering equivalents provides a straightforward and automated way of structural assessment of macromolecules based on a SAXS profile. DARA results are useful e.g. for fold recognition and finding of biologically active oligomers.

Availability and implementation:http://dara.embl-hamburg.de/

Contact:svergun@embl-hamburg.de

[Dating violence and mental health in Mexican college students]

Antecedentes:

En las últimas dos décadas, ha aumentado el interés por la promoción de la salud en el sector educativo superior, a través del programa “Universidades Saludables” promovido por la Organización Mundial de la Salud (OMS). Es importante reconocer las necesidades relacionadas con la salud de los integrantes de la comunidad universitaria, así como reflexionar sobre las acciones dirigidas a cubrirlas. Uno de los problemas prioritarios respecto a la salud mental de los jóvenes universitarios es la violencia en el noviazgo. Considerando lo anterior, los objetivos del presente estudio fueron: evaluar la violencia en el noviazgo, la sintomatología depresiva y la autoestima en estudiantes universitarios; estudiar la relación entre la violencia, la depresión y la autoestima; y promover la implementación de programas preventivos entre la comunidad universitaria.

Métodos:

Se realizó un estudio transversal y descriptivo con las respuestas de 729 estudiantes universitarios, aplicando el “Conflict in Adolescent Dating Relationship Inventory,” el Inventario de Depresión de Beck y el Inventario de Coopersmith para evaluar la autoestima.

Resultados:

Los resultados mostraron una elevada prevalencia de violencia en los jóvenes universitarios, particularmente verbal-emocional (75%). Las agresiones fueron de carácter bidireccional, tanto hombres como mujeres cometieron y sufrieron la violencia. La conducta violenta se asoció con la baja autoestima en las mujeres y con síntomas depresivos en ambos sexos.

Conclusiones:

Desde el enfoque del programa “Universidades Saludables,” es importante que las instituciones de educación superior sean promotoras de la salud mediante la creación y difusión del conocimiento, la formación de recursos humanos y la promoción de la organización comunitaria. Los resultados del estudio indican la necesidad de desarrollar programas educativos orientados a la prevención de la violencia, al manejo de emociones y a la resolución de conflictos.

[Effect of loop diuretics with different elimination half-lives on natriuresis changes and indicators characterizing the state of renal tubulointerstitial tissue]

AIM

To investigate the effect of loop diuretics with different elimination half-lives on natriuresis (NU) changes in patients with hypertensive disease (HD) and chronic heart failure (CHF).

SUBJECTS AND METHODS

Fifty-six patients who had signs of progressive CHF and needed diuretic therapy were selected from a group of the patients who had participated in our previous study of the types of natriuretic curves. They all received torasemide SR or torasemide IR.

RESULTS

It has been shown that the type of a natriuretic curve may be variable in the patients. In the toracemide IR group, NU worsens more frequently and earlier than in the toracemide SR group (p < 0.05). The type of the curve is associated with elevated Tamm-Horsfall protein (THP) levels, its transition from one to another type, and the duration of HD to the greatest degree. It has been found that the longer history of HD is, the higher effect of angiotensin II is. The probability of transition of the natriuretic curve from type 3 to 2 is 83.93% (odds ratio 11.667) from type 2 to 1 is 92.86% (odds ratio 120.00).

CONCLUSION

With time and altered NU, there is a significant deterioration of sodium excretion, and an increase in THP excretion, which is a marker for progressive tubulointerstitial fibrosis, and angiotensin II activity increases, which gives proof to the necessity of monitoring NU.

CLIC proteins, ezrin, radixin, moesin and the coupling of membranes to the actin cytoskeleton: a smoking gun?

The CLIC proteins are a highly conserved family of metazoan proteins with the unusual ability to adopt both soluble and integral membrane forms. The physiological functions of CLIC proteins may include enzymatic activity in the soluble form and anion channel activity in the integral membrane form. CLIC proteins are associated with the ERM proteins: ezrin, radixin and moesin. ERM proteins act as cross-linkers between membranes and the cortical actin cytoskeleton. Both CLIC and ERM proteins are controlled by Rho family small GTPases. CLIC proteins, ERM and Rho GTPases act in a concerted manner to control active membrane processes including the maintenance of microvillar structures, phagocytosis and vesicle trafficking. All of these processes involve the interaction of membranes with the underlying cortical actin cytoskeleton. The relationships between Rho GTPases, CLIC proteins, ERM proteins and the membrane:actin cytoskeleton interface are reviewed. Speculative models are proposed involving the formation of localised multi-protein complexes on the membrane surface that assemble via multiple weak interactions. This article is part of a Special Issue entitled: Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. Guest Editor: Jean Claude Hervé.

[Structure of neuromuscular junctions and differentiation of striated muscle fibers of mdx mice after bone marrow stem cells therapy]

Mdx mice are a model of Duchenne muscular dystrophy caused by deficiency of dystrophin. Muscles of mdx mice are characterized by high levels of striated muscle fibers death and, accordingly, by a high level of its regeneration. Moreover, the structure of neuromuscular junctions in mdx mice is altered. Changes in the structure of mdx mice neuromuscular junctions against a background of increasing differentiation of striated muscle fibers after C57BL/6 Lin (-) bone marrow stem cells transplantation were investigated. The muscles were studied in 4, 8, 16 and 24 weeks after transplantation. We observed that the level of striated muscle fibers loss was decreased from the 4th week after transplantation of bone marrow stem cells. Accumulation of muscle fibers without centrally located nuclei began from the 8th week, and dystrophin synthesis was increased at the 16th and 24th weeks after bone marrow stem cells transplantation. Longitudinal sections of quadriceps muscles of mdx mice showed decrease in the number of acetylcholine receptors clusters in neuromuscular junctions and a simultaneous increase in acetylcholine receptor clusters area during the 4th week after transplantation. In 16 weeks after bone marrow stem cells transplantation, total neuromuscular junction area was increased due to increase in the area of acetylcholine receptors clusters and to increase in their number as well. Thus, single intramuscular transplantation of C57BL/6 Lin (-) bone marrow stem cells induces an increase in differentiation of mdx mice striated muscle fibers and improves the structure of neuromuscular junctions.

Monitoring intermediate filament assembly by small-angle x-ray scattering reveals the molecular architecture of assembly intermediates

Intermediate filaments (IFs), along with microtubules, microfilaments, and associated cross-bridging proteins, constitute the cytoskeleton of metazoan cells. While crystallographic data on the dimer representing the elementary IF "building block" have recently become available, little structural detail is known about both the mature IF architecture and its assembly pathway. Here, we have applied solution small-angle x-ray scattering to investigate the in vitro assembly of a 53-kDa human IF protein vimentin at pH 8.4 by systematically varying the ionic strength conditions, and complemented these experiments by electron microscopy and analytical ultracentrifugation. While a vimentin solution in 5 mM Tris.HCl (pH 8.4) contains predominantly tetramers, addition of 20 mM NaCl induces further lateral assembly evidenced by the shift of the sedimentation coefficient and yields a distinct octameric intermediate. Four octamers eventually associate into unit-length filaments (ULFs) that anneal longitudinally. Based on the small-angle x-ray scattering experiments supplemented by crystallographic data and additional structural constraints, 3D molecular models of the vimentin tetramer, octamer, and ULF were constructed. Within each of the three oligomers, the adjacent dimers are aligned exclusively in an approximately half-staggered antiparallel A(11) mode with a distance of 3.2-3.4 nm between their axes. The ULF appears to be a dynamic and a relatively loosely packed structure with a roughly even mass distribution over its cross-section.

PRIMUS: a Windows PC-based system for small-angle scattering data analysis

A program suite for one-dimensional small-angle scattering data processing running on IBM-compatible PCs under Windows 9x/NT/2000/XP is presented. The main program,PRIMUS, has a menu-driven graphical user interface calling computational modules to perform data manipulation and analysis. Experimental data in binary OTOKO format can be reduced by calling the programSAPOKO, which includes statistical analysis of time frames, averaging and scaling. Tools to generate the angular axis and detector response files from diffraction patterns of calibration samples, as well as binary to ASCII transformation programs, are available. Several types of ASCII files can be directly imported intoPRIMUS, in particular, sasCIF or ILL-type files are read without modification.PRIMUSprovides basic data manipulation functions (averaging, background subtraction, merging of data measured in different angular ranges, extrapolation to zero sample concentration,etc.) and computes invariants from Guinier and Porod plots. Several external modules coupled withPRIMUSviapop-up menus enable the user to evaluate the characteristic functions by indirect Fourier transformation, to perform peak analysis for partially ordered systems and to find shape approximations in terms of three-parametric geometrical bodies. For the analysis of mixtures,PRIMUSenables model-independent singular value decomposition or linear fitting if the scattering from the components is known. An interface is also provided to the general non-linear fitting programMIXTURE, which is designed for quantitative analysis of multicomponent systems represented by simple geometrical bodies, taking shape and size polydispersity as well as interparticle interference effects into account.

[Treatment strategies in exudative otitis media in children with aquired cleft lip and palate]

The paper presents incidence of hearing problems in 100 children with aquired cleft lip and palate (ACLP) aged 1 to 16 years. An age aspect of the problem is analysed. The patients were at different stages of rehabilitation for ACLP. Conservative and surgical policies in management of children with exudative otitis media and ACLP are analysed. Surgical results depending on the disease stage are provided.