Impact of abutment microstructure and insertion depth on crestal bone changes at nonsubmerged titanium implants with platform switch.

Objectives: To assess the impact of microgrooved abutments and the insertion depth on crestal bone changes at titanium implants with platform switch.

Materials And Methods: A total of n = 3 titanium implants (conical abutment connection) were inserted in each hemimandible of n = 6 foxhounds with the implant shoulder (IS) located at either epicrestal, supracrestal (+1 mm), or subcrestal (-1 mm) positions and randomly (split-mouth design) connected with machined or partially microgrooved healing abutments. At 20 weeks, tissue biopsies were processed for histological (primary outcome: net bone loss - NET) analyses.

[Synthesis of peptide fragments of high-affinity receptor FcepsilonR1 and study their binding with allergen-specific immunoglobulin E].

High-affinity receptor FcepsilonR1 is a key substance which participates in IgE-dependent allergic reactions of immediate type. A minimal sequence Arg136-Asn137-Trp138-Asp139, which takes part in binding with C3 and C4 fragments of IgE was determined by methods of computer analysis. As possible analogs of FcepsilonR1 receptor, capable of binding to Fc-fragment IgE, a number of peptide compounds containing this sequence were proposed.

[New bioaffine sorbents for selective elimination of autoantibodies against human thyroperoxidase in autoimmune thyroid diseases].

New bioaffine sorbents containing bioselective ligand, synthetic analog of the human thyroperoxidase antigenic determinant--tetrapeptide H-Glu-Gln-betaAla-Lys-OMe, immobilized on two polymeric matrixes--a polyacrylamide gel and CNBr-activated sepharose 4B were synthesized. The offered immunosorbents were shown have high selectivity in relation to autoantibodies against thyroperoxidase and can find an application for medicine and experimental biochemistry for selective elimination of autoantibodies from serum or plasma of the patients suffering from autoimmune thyroid diseases.

Effect of N-terminal tripeptides of bombesin, litorin, and their analogue on body temperature and vasomotor responses.

Intranasal administration of bombesin caused hypothermia in rats maintained under cold conditions. N-terminal tripeptide of bombesin exhibits intrinsic vasomotor activity, while intranasal administration of its modified analogue produced a more potent hypothermic effect than intranasal bombesin.

[Synthesis of modified fragments of fibrinogen and their effect on the activity of proteolytic enzymes].

New analogues of the Gly-Pro-Arg and Arg-Gly-Asp fragments of fibrinogen were synthesized: Gly-Pro-Arg-Pro (I), Gly-Pro-Arg-Pro-Met-OMe (II), Gly-Pro-Arg-Pro-Phe (III), Gly-Pro-Arg-Pro-Asp (IV), Gly-Pro-Arg-Pro-Glu (V), and Arg-Asn-Trp-Asp (VI). Their effect on the activity of proteases of various types was studied with the method of lysis of fibrin plates. All the peptides were found to inhibit plasmin activity (by 60-85%) and the gamma-subunit of nerve growth factor (by 55-93%).

[The structure-antiaggregative activity relationship in a series of Arg-Gly-Asp analogs].

A series of analogues of Arg-Gly-Asp tripeptide, the common structural element of most of the integrin receptor ligands, possessing different conformational features for the interaction with platelet receptors, were synthesized by the methods of conventional peptide chemistry for use in the search for antithrombotic agents. The distance between the guanidine group of Arg and the beta-carboxyl group of Asp was shown to affect the antiaggregative activity. A potent inhibitor of platelet aggregation, tripeptide Arg-betaAla-Asp, with IC50 = 10.

Improvements in the selective perception and training of rats using an original analog of the C-terminal fragment of vasopressin.

This report presents studies on the effects of intranasal administration of five doses (0.001, 0.01, 0.

The effects of a novel analog of the C-terminal fragment of vasopressin on the behavior of white rats.

The effects of an arginine-vasopressin fragment, Ac-D-MPRG, on the movement activity and orientational-investigative activity of white rats were studied. Peptide was given intranasally at doses of 0.001, 0.

The effects of analogs of the C-terminal fragment of arginine-vasopressin on the dynamics of development of a conditioned active avoidance response in rats.

This paper reports studies of the effects of original analogs of the C-terminal fragment AVP(6-9), D-MPR and D-MPRG, on the development of a conditioned active avoidance response in rats; agents were given intranasally over a wide range of doses. The most effective does of D-MPR was 0.1 microgram/kg, and the most effective dose of D-MPRG was 0.

[Improvement of the selective perception and learning with the analog of C-terminal fragment of vasopressin in rats].

New analogue of the AVP(6-9), the D-MPRG was administered intranasally in different doses. The administration improved the process of conditioning. The most efficient dose turned out to be 0/01 mcg/kg.

[The effect of an original analog of the C-terminal fragment of vasopressin on the behavior of white rats].

The influence was studied of a new analog of C-terminal fragment of argininvasopressin Ac-D-MPRG on locomotor and exploratory activity of rats. The peptide injected intranasally in the doses of 0.001, 0.

[The effect of analogs of the C-termination fragment of arginyl vasopressin on the dynamics of the acquisition of an active avoidance conditioned reaction in rats].

The effect of original analogues of the 6-9 C-terminal AVP fragment, D-MRP and D-MPRG, on the active avoidance behaviour of rats was studied using intranasal administration in a wide range of doses. The dose in 0.1 mcg/kg was the most efficient for D-MPR and 0.

The neurotropic activity of a structural analog of ACTH(5-7).

The tripeptide glutamyl-arginyl-proline (ERP) mimicking some structural features of the N-terminal fragment of adrenocorticotropic hormone, ACTH(5-7), has been synthesized. In contrast with ACTH fragments, ERP (0.015-0.

[The interrelationship between the electronic structure and the radioprotective activity of indolylalkylamines].

Using MNDO and geometry optimization the ground state of indolylalkylamine molecules' monocationic form was calculated. Statistical relationship was established between charge distribution near atom in the fifth position and radioprotective activity of indolylalkylamines.

Litorin and litorin-albumin conjugate as effective regulators of body temperature in rats.

Intraperitoneal injection of the bombesin-like peptide litorin (0.5 ml of a 10(-5) M solution) led to a short-lived decrease in the body temperature (maximum of 0.9 degrees C) of laboratory rats.

[Chemical modification of antibodies against carcino-embryonal antigen].

Chemical modification of different amino acid residues and the carbohydrate moiety of antibodies to carcino-embryonic antigen (CEA) was used to elucidate their role in the interaction with CEA and to evaluate the effect of antibody modification and steric factor in immunosorbent synthesis. The distribution of the modified groups among the structural fragments of IgG and the levels of changes in the antigen-binding properties of modified antibodies were investigated. The Fc-fragment of IgG was shown to contain carboxylic groups, tyrosine and histidine residues, whose modification influences the antigen-binding properties as a result of generalized conformational changes in the IgG molecule.

[Intake of water and sodium chloride solution by the rats after central administration of litorin and immunization with litorin-bovine serum albumin conjugate].

Central injection of litorin suppressed water and sodium chloride solution intake, and also decreased the preference of saline of unrestrained rats during 1 hour test. Active immunization of animals with litorin-bovine serum albumin conjugate led to the augmentation of their daily saline preference. Immunized rats increased also avidity to salt after deprivation, though the consumption volume of liquids decreased.

[A method of determining fragments of peptide bioregulators responsible for interaction with receptors].

A method for investigating the relationship between chemical structure of peptide molecules and their biological activity is suggested. It is based on a few statistical algorithms which are described. The results of the method testing on the thyrotropin-releasing hormone analogs are presented.

[Theoretical conformational analysis of a encephalitogenic peptide molecule and a study of the structure-activity relationship in a series of its analogs].

Semi-empirical energy calculations are used to determine all low-energy conformations of Trp-containing fragment 113-121 of myelin basic protein (experimental allergic encephalomyelitis inducing peptide). The computed conformations are compared with the results of physico-chemical experiments and data on biological testing of the encephalitogenic peptide analogs. The three computed structures are shown to be in a good agreement with the available experimental evidence.

[Optimization of methods of immobilization of anti-immunoglobulins. Equilibrium parameters of the interaction of immobilized antibodies with an antigen].

Methods for immobilization of anti-immunoglobulins on insoluble supports were optimized, and the interaction of immunoadsorbents obtained with [125I]-labeled rabbit IgG was investigated. It was shown that this interaction can be adequately described by a rather simple equilibrium model which reflects the interaction of a monovalent antigen with two independent types of binding sites. Within the framework of this model the association constants as well as the concentrations of high affinity binding sites which influence the capacity and efficiency of the separation system were determined.

[Calculation of stable conformations of the molecule of a serum thymic factor].

Stable conformations of "facteur thimique sérique" (FTS) were determined by semi-empirical conformational analysis. The interpretation of the calculation results in combination with data on biological activity of the conformationally restricted FTS analogues enabled the delineation of a possible "biologically active" conformation.

[Theoretical conformational analysis of delta-sleep inducing peptide].

The spatial structure of o-sleep-inducing peptide has been determined by means of semi-empirical conformational analysis of its overlapping fragments. Possible intramolecular contacts in the most stable conformations are discussed. The essential role of electrostatic interactions is emphasized.