Rechargeable anticandidal denture material with sustained release in saliva.

OBJECTIVE: Candida-induced denture stomatitis is a common debilitating problem among denture wearers. Previously, we described the fabrication of a new denture material that released antifungal drugs when immersed in phosphate buffered saline. Here, we use more clinically relevant immersion conditions (human saliva; 37°C) and measure miconazole release and bioactivity. MATERIALS AND METHODS: Disks were prepared by grafting PNVP [poly(N-vinyl-2-pyrrolidinone)] onto PMMA [poly(methylmethacrylate)] using plasma initiation (PMMA-g-PNVP) and then loaded with miconazole. Drug-loaded disks were immersed in 10-100% human saliva (1-30 days). Miconazole release was measured and then tested for bioactivity vs miconazole-sensitive and miconazole-resistant Candida isolates. RESULTS: HPLC was used to quantify miconazole levels in saliva. Miconazole-loaded disks released antifungal drug for up to 30 days. Higher drug release was found with higher concentrations of saliva, and, interestingly, miconazole solubility was increased with higher saliva concentrations. The released miconazole retained its anticandidal activity. After immersion, the residual miconazole could be quenched and the disks recharged. Freshly recharged disks displayed the same release kinetics and bioactivity as the original disks. Quenched disks could also be charged with chlorhexidine that displayed anticandidal activity. CONCLUSIONS: These results suggest that PMMA-g-PNVP is a promising new denture material for long-term management of denture stomatitis.

[Electroimpedance Methods of Investigation of Cardiac Activity].

AIM: of the present work was assessment of possibility to use modern electroimpedace methods for the study of activity of the heart. Electroimpemdace methods of measurement for many years remained in the shadow of other diagnostic methods because of low accuracy in evaluation of various parameters. At present, there are technologies of measurement which allow to carry out electroimpedance investigations of cardiac activity dynamically and with acceptable accuracy. In this article, we present methods of electroimpedace measurements created in Institute of Biomedical Equipment of N.E. Bauman Technical University. These methods allow to assess dynamics of movement of ventricles of the heart, to evaluate volume parameters of cardiac activity and all temporal phases of activity of cardiac chambers. We also present data of studies on healthy volunteers and patients of cardiological profile. It has been shown that patients with atrial fibrillation have substantially increased duration of electrical and mechanical activity of atria and ventricles as well as lowed ejection fraction compared with other participants of experiments.

The ADRON-RM Instrument Onboard the ExoMars Rover.

This overview presents the physical principles, design, measurement capabilities, and summary of planned operations of the autonomous detector of radiation of neutrons onboard rover at Mars (ADRON-RM) on the surface of Mars. ADRON-RM is a Russian project selected for the joint European Space Agency-Roscosmos ExoMars 2020 landing mission. A compact passive neutron spectrometer, ADRON-RM, was designed to study the abundance and distribution of water and neutron absorption elements (such as Cl, Fe, and others) in the martian subsurface along the path of the ExoMars rover. Key Words: Mars exploration-Surface-Neutron Spectroscopy-Water. Astrobiology 17, 585-594.

A comparative study of LaBr3(Ce(3+)) and CeBr3 based gamma-ray spectrometers for planetary remote sensing applications.

The recent availability of large volume cerium bromide crystals raises the possibility of substantially improving gamma-ray spectrometer limiting flux sensitivities over current systems based on the lanthanum tri-halides, e.g., lanthanum bromide and lanthanum chloride, especially for remote sensing, low-level counting applications or any type of measurement characterized by poor signal to noise ratios. The Russian Space Research Institute has developed and manufactured a highly sensitive gamma-ray spectrometer for remote sensing observations of the planet Mercury from the Mercury Polar Orbiter (MPO), which forms part of ESA's BepiColombo mission. The Flight Model (FM) gamma-ray spectrometer is based on a 3-in. single crystal of LaBr3(Ce(3+)) produced in a separate crystal development programme specifically for this mission. During the spectrometers development, manufacturing, and qualification phases, large crystals of CeBr3 became available in a subsequent phase of the same crystal development programme. Consequently, the Flight Spare Model (FSM) gamma-ray spectrometer was retrofitted with a 3-in. CeBr3 crystal and qualified for space. Except for the crystals, the two systems are essentially identical. In this paper, we report on a comparative assessment of the two systems, in terms of their respective spectral properties, as well as their suitability for use in planetary mission with respect to radiation tolerance and their propensity for activation. We also contrast their performance with a Ge detector representative of that flown on MESSENGER and show that: (a) both LaBr3(Ce(3+)) and CeBr3 provide superior detection systems over HPGe in the context of minimally resourced spacecraft and (b) CeBr3 is a more attractive system than LaBr3(Ce(3+)) in terms of sensitivities at lower gamma fluxes. Based on the tests, the FM has now been replaced by the FSM on the BepiColombo spacecraft. Thus, CeBr3 now forms the central gamma-ray detection element on the MPO spacecraft.

Synthesis and evaluation of anti-HSV activity of new 5-alkynyl-2'-deoxyuridines.

Eight 5-alkynyl-2'deoxyuridines containing different bulky substituents have been prepared and tested against HSV-1 in Vero cells. The compounds show positive antiviral activity. There is no obvious correlation between activity and substituent size. The nature of the linker between uracil and a substituent appears to be more important for antiviral properties: nucleosides containing arylethynyl groups show higher activity.

Endogenous tumour necrosis factor-alpha sensitise melanoma cells to glucosaminylmuramyl dipeptide.

Flow cytometry was used to demonstrate that cultured human melanoma BRO cells expressed membrane-bound tumour necrosis factor-alpha (TNF-alpha) and were able to release TNF-alpha upon treatment with glucosaminylmuramyl dipeptide (GMDP). The released TNF-alpha was shown to prime melanoma cells, previously unable to respond to GMDP by increasing expression of melanoma-associated antigens, making them sensitive to GMDP treatment.

Glucosaminylmuramyldipeptide-induced changes in phenotype of melanoma cells result in their increased lysis by peripheral blood cells.

Flow cytometry was used to show that biologically active N-acetylglucosamine-containing muramylpeptides (GMPs) induced in vitro dose-dependent increase in the expression of tumor-associated antigens (TAAs) characteristic for colon and mammary gland carcinomas, melanoma and lung adenocarcinoma. Forty to two hundred percent enhancement in TAA-expressing cells was observed after 18-48 h incubation with GMPs. In contrast, MHC class I antigen expression was not altered. Using MTT and chromium-release assays, melanoma cells treated in vitro with GMDP were shown to be more susceptible to killing by peripheral blood cells of healthy donors than non-treated cells. Fractionation of blood cells revealed that platelets were responsible for this effect.

Immunoregulatory properties of hexapeptide isolated from porcine bone marrow cell culture.

Myelopeptide 1 (MP-1) is hexapeptide originally isolated from porcine bone marrow cell culture. It was synthesized and its immunoregulatory properties were studied. MP-1 caused a 1.5-2-fold dose-dependent increase of antibody production in the culture of mouse immune lymph node cells. It abolished Con A induction of T suppressors in the suspension of mouse spleen cells and counteracted the inhibitory effect of T suppressors on antibody production. The inoculation of MP-1 (1 x 10(-9) g/mouse) to mice two weeks after their gamma-irradiation (2 Gy) resulted in an increase of antibody production up to 80.2 +/- 15.5% as compared to that in the irradiated control 37.6 +/- 12.0%. Immunofluorescent analysis revealed the specific binding of MP-1 with receptors on the target cells in the suspension of mouse spleen cells. It is supposed that MP-1 participates in the immunoregulatory processes in the living organism.

Conjugates of oligonucleotides with polyaromatic fluorophores as promising DNA probes.

Conjugates of pyrene and perylene with oligodeoxynucleotides were synthesized and tested as hybridisation probes. A 13-mer containing a 3-peryleneacetic acid residue attached to the 5' end through a hexamethylenediamine linker showed no response in the fluorescent spectrum upon hybridisation to the complementary sequence. At the same time, pyrene-labelled probes are sensitive to duplex formation. A pyrene pseudonucleotide unit based on 4-(1-pyrenyl)-1,3-butanediol can be introduced into any predetermined position(s) of the oligonucleotide chain. The probes polylabelled in this fashion displayed considerable changes in the excimer-to-monomer fluorescence intensity ratio after duplex formation. The internal location of two pyrene residues in the probe provides a drastic enhancement of excimer fluorescence (approximately 470 nm) upon hybridisation. When two pyrene units were brought into close proximity to two pyrenes in the complementary strand upon duplex formation, strong excimer emission at approximately 450 nm was detected. This effect provides a basis for a sensor construction designed to detect nucleic acid hybridisation.

Time scales of overdamped nonlinear Brownian motion in arbitrary potential profiles.

This paper presents a new approach and new results concerning the problem of the rate of the nonlinear Brownian motion in a field of force. Within the scope of one-dimensional overdamped Brownian motion the exact values of time scales are obtained in detail for three types of arbitrary dimensionless potential profiles varphi(x) which differ from one another by their limiting values at x=+/- infinity. Three time scales, the relaxation time, the decay time of a metastable state and the life time of a nonstable state, are found via given potential profiles varphi(x) by explicit quadrature formulae, as it takes place for the well-known mean first passage times. Specific examples are considered. (c) 1997 American Institute of Physics.

The kinetics of liquid-gas phase transitions of a Van der Waals substance with fluctuations taken into account.

The isotherm of a Van der Waals substance, containing only stable points, is obtained on the basis of using the thermodynamic potential for nonequilibrium states and taking fluctuations into account. It is shown that in the vicinity of two-phase states this isotherm is close to the horizontal phase equilibrium line, defined by Maxwell's rule. The lifetimes of the metastable states of the Van der Waals substance, which depend on the intensity of the external fluctuations and the number of particles in the system, are estimated. (c) 1994 American Institute of Physics.

[Synthesis and fluorescent properties of oligonucleotides, containing a new fluorescent marker--n-(2-benzoxazolyl)tolane]. / Sintez i fluorestsentnye svoistva oligonukleotidov, soderzhashchikh novuiu fluorestsentnuiu metku--n-(2-benzoksazolil)tolan.

A functional (dihydroxybutyl) derivative of p-(2-benzoxazolyl)tolane, a fluorescent label novel for biopolymers, was synthesized. The functionalized solid support obtained on its basis was employed in the synthesis of oligodeoxynucleotides 3-terminally labeled with benzoxazolyltolane (these oligonucleotides also contained 1-phenylethynylpyrene residues). This fluorophore within its dihydroxybutyl derivative and the oligonucleotides modified with it displays an intensive fluorescence characterized by a high Stokes shift. The oligonucleotides labeled with this fluorophore are potential probes sensitive to the biopolymer microenvironment.

[Synthesis and fluorescent properties of 5-(1-pyrenylethynyl)-2'- deoxyuridine-containing oligodeoxynucleotides]. / Sintez i fluorestsentnye svoistva 5-(1-pirenilétinil)-2'-dezoksiuridinsoderzhashchikh oligodezoksinukleotidov.

Novel reagents for the fluorescent labeling of oligo- and polynucleotides have been prepared: 5-(1-pyrenylethynyl)-2'-deoxyuridine 3'-phosphoramidite and a solid support carrying this nucleoside. Oligonucleotides containing one or several modified units have been synthesized, and the fluorescence of these probes has been shown to change upon hybridization with the complementary sequence.

[Properties of urease immobilized by chemical binding to a derivatives of cellulose]. / Issledovanie svoistv ureazy, immobilizovannoi putem khimicheskogo prisoedineniia k proizvodnym tselliulozy.

A comparative study of properties of soluble urease and urease immobilized by its binding to cellulose derivatives was carried out. Upon chemical binding of urease to cellulose derivatives the Mikhaelis constant and pH optimum for the enzyme action changed insignificantly. Maximum enzymic activity of soluble and immobilized urease occurred at 50 degrees C. The energy of activation of urea hydrolysis by urease during enzyme immobilization also changed insignificantly.

[Use of central analgesia in emergency abdominal operations]. / Primenenie tsentral'noi anal'gezii pri ekstrennykh abdominal'nykh operatsiiakh.

In 48 patients urgent operative interventions on organs of the abdominal cavity were performed against the background of the adequate central analgesia by phentanyl (0,02 mg/kg). The authors think the method to be inexpedient in operative interventions shorter than 60 min.

[Selection of the treatment method in diaphyseal fractures of 2 segments of the upper or lower limbs]. / Vybor metoda lecheniia diafizarnykh perelomov dvukh segmentov verkhnei ili nizhnei konechnosti.

The authors propose a working scheme to choose the method of treatment of diaphyseal fractures of segments of the upper and lower extremities with an obligatory application of perosseous osteosynthesis by the Ilizarov apparatus in combination with other curative measures. The scheme described was used in 26 patients and gave good anatomical and functional results.

[Diagnosis, outcome prognosis and treatment strategy in inhalation trauma in patients with thermal injuries]. / Diagnostika, prognozirovanie iskhoda i lechebnaia taktika pri ingaliatsionnoi travme u postradavshikh s termicheskimi porazheniiami.

Sixty-seven therapeutic fibrobronchoscopies (FBS) were carried out in burnt patients with suspected inhalation injuries at Center for Burns at the Janelidze Institute of Emergency Care in 1996-1998. The severity of inhalation injury was assessed from the extent and severity of mucosal edema, spot hematomas and their type, erosions and ulcers, discharge, and ventilation obstruction. An original score is developed for evaluating the severity of inhalation injuries in burnt patients. Inhalation injuries were diagnosed in 63 patients. FBS was performed with tracheobronchial lavage with antibiotics, proteolysis enzymes, and repair stimulants. Mortality among burnt patients with inhalation injuries was decreased to 38%.

Hydrogen mapping of the lunar south pole using the LRO neutron detector experiment LEND.

Hydrogen has been inferred to occur in enhanced concentrations within permanently shadowed regions and, hence, the coldest areas of the lunar poles. The Lunar Crater Observation and Sensing Satellite (LCROSS) mission was designed to detect hydrogen-bearing volatiles directly. Neutron flux measurements of the Moon's south polar region from the Lunar Exploration Neutron Detector (LEND) on the Lunar Reconnaissance Orbiter (LRO) spacecraft were used to select the optimal impact site for LCROSS. LEND data show several regions where the epithermal neutron flux from the surface is suppressed, which is indicative of enhanced hydrogen content. These regions are not spatially coincident with permanently shadowed regions of the Moon. The LCROSS impact site inside the Cabeus crater demonstrates the highest hydrogen concentration in the lunar south polar region, corresponding to an estimated content of 0.5 to 4.0% water ice by weight, depending on the thickness of any overlying dry regolith layer. The distribution of hydrogen across the region is consistent with buried water ice from cometary impacts, hydrogen implantation from the solar wind, and/or other as yet unknown sources.