Transformation of Nano-Size Titanium Dioxide Particles in the Gastrointestinal Tract and Its Role in the Transfer of Nanoparticles through the Intestinal Barrier.

In this work, the size transformation of the TiO2 nanofraction from pharmaceutical grade E171 powder was studied during its transit through the gastrointestinal tract (GIT). It was shown that pharmaceutical-grade TiO2 powder contained about 0.68% (w/w) of particles smaller than 240 nm in diameter. In the observed GIT transit process the TiO2 nanoparticles were agglomerated up to 150-200 nm in simulated salivary fluid, with gradual agglomerate enlargement up to 300-600 nm and more than 1 micron in simulated gastric fluid. In the intestinal fluid the reverse process occurred, involving a decrease of agglomerates accompanied by the formation of a small fraction with ~50 nm average size. This fraction can be further involved in the histohematic transport process. The acidity degree (pH) and mineral composition of solutions, as well as the transit speed along the gastrointestinal tract, influence the nature of the particle transformation significantly. The rapid passing between the gastrointestinal tract sections creates conditions for a decrease in part of the TiO2 particles, up to 100 nm, and may be associated with the violation of the structural and functional integrity of the intestinal mucus layer.

[Comparative characteristics of root formation and mineralization features in the permanent teeth according to cone beam computed tomography data]. / Sravnitel'naya kharakteristika osobennostei formirovaniya kornei i ikh mineralizatsii v postoyannykh zubakh po dannym konusno-luchevoi komp'yuternoi tomografii.

AIM: Studying features of root formation and mineralization in permanent teeth of children and adults. MATERIAL AND METHODS: The root formation features were studied in 2800 children's permanent teeth aged 6-15 in Moscow and Moscow region; cone beam computed tomography was performed according to the orthodontic indications. CBCT method was also used to study the apical foramen diameter, width of the permanent teeth periodontal fissure, perform clinical examination and treatment of youngsters and young people (aged 12-25, n=180) with pulpitis (K04.03), apical periodontitis (K04.5) and uncompleted processes of hard tissues mineralization and hard tissues with different degrees of maturation; as well as groups of adults (aged 30-50, n=170) with pulpitis (K04.03) and apical periodontitis (K04.5) in permanent teeth with completed processes of hard tissues mineralization. RESULTS: CBCT is objective for visualizing teeth of both jaws which allows determining root formation stages in children's permanent teeth and high precision during one examination visit. Teeth Youngster's and young peopl's teeth have expressed anatomical and structural features during 5-6 years after root formation completion: apical foramen diameter of 0.71±0.004 mm, periodontal fissure width of 1.01±0.004 mm, hard tissues density in apical part of root is 12282.71 units HU, which is different from analogous readings in people over 25 where they make 0.61±0.004 mm (p<0.05); 0.71±0.003 mm (p<0.05); 1428.6±0.89 units HU (p<0.05) respectively. CONCLUSION: CBCT is a useful tool for visualization of dental roots allowing precise definition of root developmental stage in permanent teeth in children by one diagnostic imaging procedure.

Electromagnetic microwave generation by acoustic vibrations gives rise to nanoradiophotonics.

The development of new methods for generating pulsed electromagnetic microwave radiation is currently an actively developing area of research. Schemes for microwave radiation generation with optical pumping are of great interest. In this paper we propose and experimentally demonstrate principally new method for photonic generation of microwave electromagnetic radiation. This method is based on the use of radiation of charged submicron particles oscillating at their own acoustic frequency. Laser radiation of the optical range implements an effective buildup of acoustic vibrations of submicron particles forming the system under study, according to the Raman mechanism.

Coherent Stokes and anti-Stokes high-order components generation by biharmonic pumping via stimulated low-frequency Raman scattering.

In this Letter, we report on experimental effective coherent multiple Stokes and anti-Stokes high-order components generation by Stokes pulse injection at the process of stimulated low-frequency Raman scattering. This process can be used for effective generation the tunable spectral comb consisting of several equidistant spectral lines separated by a constant frequency spacing of several GHz.

Study of Immunomodulatory Effects of Extracellular HSP70 in a Mouse Model of Allergic Airway Inflammation.

Immunostimulatory properties of extracellular heat shock proteins 70 kDa (HSP70) became interesting for investigators a long time ago. However, in recent years a series of works showing a significant relation of the immunostimulating effects of recombinant HSP70 to contamination of the protein samples with bacterial endotoxins (lipopolysaccharide, LPS) has been published. The authors showed that intensive elimination of LPS from the protein samples resulted in inversion of immunostimulating effects of HSP70 to immunosuppressive activity of the protein. Nevertheless, at present the conception of immunostimulating, proinflammatory action of extracellular HSP70 is the most common. In this work, we studied immunomodulatory effects of exogenous HSP70 in a mouse model of allergic inflammation of airways. We also analyzed the dynamics of the level of the extracellular pool of HSP70 in the site of inflammation. The results demonstrated a considerable content of extracellular HSP70 in bronchoalveolar lavages with dynamics reflecting the stages of development of the induced inflammation. Oropharyngeal injection of exogenous HSP70 in the acute phase of allergic inflammation of airways resulted in significant suppression of the inflammatory process, which conforms to published data demonstrating an immunosuppressive activity of the extracellular pool of HSP70.

[Modulating Effect of Extracellular HSP70 on Generation of Reactive Oxigen Species in Populations of Phagocytes].

Reactive oxygen species (ROS) produced by phagocytic cells of the innate immune system play an important role in the first line of defense protecting the host from pathogens. The NADPH oxidase multi-subunit complex is the main source of ROS in all types of the phagocytes. Formation of the membrane-associated enzyme complex and its activity are dependent on many different factors controlling both intensification and suppression of the ROS production rate. However, the evidences are emerging in recent years indicating existence of poorly studied mechanisms of restriction of ROS generation level in phagocytes directed at protection of host tissues in the sites of inflammation from destruction caused by the oxygen free radicals. Our previous data and results of other authors demonstrate that a mechanism of the limitation of ROS production by phagocytes may by connected with immunomodulating activity of extracellular pool. of HSP70. In the present work, we used inhibitors of NADPH oxidase and in vitro cultures of different phagocytes to study a possible relationship between down-regulating effect of exogenous HSP70 on ROS generation and the interaction of the protein with the enzyme subunits. Our results confirmed the literature data concerning the ability of extracellular HSP70 to modulate NADPH oxidase activity and demonstrated for the first time an inhibitory effect of the protein on intracellular ROS generation in phagocytes.

Susceptibility of mice to invasive aspergillosis correlates with delayed cell influx into the lungs.

Ubiquitous fungus Aspergillus fumigatus (A. fumigatus) is involved in invasive pulmonary aspergillosis (IPA), a frequent infection in immunocompromized patients. Genetic differences are likely to play a role predisposing to IPA. This study was aimed to compare six genetically different mouse strains in their susceptibility to IPA and to determine possible mechanisms involved in the pathogenesis of this infection. Immunosuppressed BALB/c and C57BL/6 mice infected with A. fumigatus conidia were more resistant to IPA than DBA/1, DBA/2, CBA, and A/Sn strains. Phagocytosis of A. fumigatus conidia by blood polymorphonuclear neutrophils (PMN) or bone marrow derived dendritic cells showed no difference between strains. All IPA susceptible strains demonstrated decreased PMN influx into the lungs during infection compared with resistant strains. Flow cytometry analysis of the composition of lung infiltrating cells showed that IPA susceptible mice had a decreased number of phagocytes before the infection. After infection the numbers of Gr-1(+)CD11b(+) PMN cells in the lungs of immunosuppressed mice increased from 10-20% to 50-60% while the percentage of CD11(+)F4/80(+) resident macrophages was unchanged. Among susceptible strains DBA/2 and A/Sn have a defect in C5 component of complement. Injection of normal serum into complement deficient but not into complement sufficient CBA or DBA/1 mice significantly improved their survival. We showed that complement replacement significantly increased PMN homing to the lungs of complement deficient mice. Thus, defect in complement system can predispose to IPA. Our results demonstrated that early influx of PMN into the lungs of mice is important for the resistance to IPA.

[Dynamics of indicators of the "skin window" and change in body reactivity upon trauma]. / Dinamika pokazatelei "kozhnogo okna" i izmenenie reaktivnosti organizma pri travmakh.

The dynamics of indicators of the "skin window" was studied in 118 patients with fractures of the bones. The dynamics of changes of the indicators was found to correspond to severity of the trauma. The picture of dermocytograms in patients with complications was different as compared with that of patients without complications. The method can be used for the estimation of reactivity of the organism in clinical practice.

[A method for evaluating a diagnostic inflammatory focus by using the "cold test"]. / Metod otsenki diagnosticheskogo ochaga vospaleniia s pomoshch'iu "kholodovogo testa".

Clinico-morphological test for the quantitative evaluation of exudative and cell response in the diagnostical inflammatory focus in various forms of human pathology is developed. The values in practically healthy persons are established. The possibilities of the test use for the prognosis of disease and the development of postoperative complications in patients with cold trauma are shown.

[Dynamics of indicators of dermocytograms and reparative capacity of the body in burns]. / Dinamika pokazatelei dermotsitogramm i reparativnye sposobnosti organizma u obozhzhennykh.

The investigation of dermocytograms by a modified method of the "skin window" in 101 patients with different square surfaces of deep burns has shown that the dynamics of mononuclear content is dependent on the injury degree. Lower parameters of mononuclear content in dermocytograms during the course of treatment correspond to the disturbance of reparative capacities of the organism in groups of patients with the complicated course of the disease. The "skin window" test can be used for the treatment since it shows the degree of the burn trauma dynamics and character of its course, facilitates the prognosis of complications.