Modified kinetics of generation of reactive species in peripheral blood of patients with type 2 diabetes

Level of reactive species in blood is an important pathogenic factor in diabetes mellitus leading to dysfunctions of vascular endothelial and smooth muscle cells and coagulation system abnormality. A massive release of reactive species (respiratory burst), catalyzed by NADPH oxidase in blood phagocytes, is not well understood in diabetes. The work aimed to study kinetics of response to microbial particles in blood to specify changes in regulatory mechanisms of generation of reactive species in patients with type 2 diabetes. Production of reactive species in blood and isolated granulocytes was measured by luminol-dependent chemiluminescence. Respiratory burst was initiated by serum opsonized zymosan in blood samples and phorbol ester in cell samples. Kinetic parameters were calculated from experimental kinetic curves of chemiluminescence intensity. ROC curve analysis and mathematical modeling were used to reveal the most significant predictors and clarify specific mechanisms of NADPH oxidase activation. It was shown that kinetic parameters of response to opsonized zymosan (lag-time, response rate, amplitude, production of reactive species) were higher in blood of patients than controls. Amplitude and response rate were the most statistically significant predictors for distinguishing patients and controls at high glucose. It indicated NADPH oxidase activation was the target of hyperglycemia. Mathematical modeling showed hyperglycemia increased stability of NADPH oxidase complex, decreased synchronization of its assembling and elevated neutrophil capacity to phagocytosis in patients. Weak or no dependence of response kinetics on ionomycin concentration was shown in patients indicating changed Ca²⁺-dependent mechanism of NADPH oxidase activation. Hyperglycemia in type 2 diabetes causes disturbances in mechanisms of NADPH oxidase activation associated with both phagocytosis and the state of intracellular signaling systems, including Ca²⁺-dependent. We suggest that NADPH oxidase in blood granulocytes can be a promising target for clinical intervention improving management of diabetic complications associated with inflammation.

Effect of orthostasis on the regulation of skin blood flow in upper and lower extremities in human

OBJECTIVE

The research is aimed to investigate interactions between cardiovascular signals and to assess contributions of central and local mechanisms to skin blood flow regulation in upper and lower extremities at rest and under orthostasis.

METHODS

Heart rate variability, respiration, forearm, and foot skin blood flow were assessed at rest and during postural test in 25 healthy volunteers. Spectral analysis was performed. Phase synchronization degree of analyzed signals was determined by group phase wavelet coherence function.

RESULTS

Skin blood flow was lower on foot at rest and during postural test than on forearm. High-frequency component of heart rate variability was higher at ~0.3 Hz during postural test versus rest. Blood flow oscillation amplitudes on the foot were lower in frequency range including respiratory interval at rest than on forearm. Postural exposure increased amplitude of foot blood flow oscillations in respiratory interval and decreased amplitudes in cardiac interval versus rest. Orthostasis increased group wavelet phase coherence between foot blood flow and heart rate variability or respiration, as well as between forearm and foot blood flow at 0.3 Hz corresponding to respiration.

CONCLUSIONS

The contribution of central mechanisms associated with respiration to blood flow regulation increased in lower extremities during orthostasis.

[Modern achievements of the functional diagnostics in dentistry]

The article presents the development of functional research methods in the maxillofacial region, methods of their application and the results of scientific research on the study of the neuromuscular balance of the masticatory muscles with defects and deformations in the maxillofacial region. Methods of blood circulation research (laser doppler flowmetry, ultrasound dopplerography, computer capillaroscopy) have been developed and implemented in the tissues of the maxillofacial region: periodontal, tooth pulp, in the mucous membrane of the alveolar ridge, which allowed us to study the mechanisms of disease pathogenesis and monitor the effectiveness of treatment in the maxillofacial region.

[The use of photodynamic therapy in the complex treatment of chronic generalized moderate periodontitis]

OBJECTIVE

Improving the effectiveness of the treatment of chronic generalized periodontitis by photodynamic therapy (PDT) due to clinical and functional validation of the effects of a photosensitizer.

MATERIAL AND METHODS

A clinical and functional study and treatment of moderate chronic generalized periodontitis was carried out in 60 people (24 males and 36 females) aged 35 to 50 years without somatic pathology with orthognathic bite. The patients were divided into 2 groups depending on the type of treatment: group 1 (main) included 30 patients (17 males and 13 females, mean age of patients was 42.5±3.3 years) who received comprehensive treatment consisting of oral sanitation, removal of dental plaque and curettage of periodontal pockets followed by PDT with 1% Geleophor gel using an AFS Spektr LED emitter with a wavelength of 660 nm and a power of 2.5 W, the course consisted of 4 procedures with exposure time of 7 minutes each; group 2 (control) included 30 patients (11 males and 19 females, mean age of patients was 43.0±2.1 years) undergoing standard treatment followed by protective capping with no active therapeutic agent. The state of microcirculation in tissues was studied by the laser Doppler flowmetry (LDF) using the LAKK-M device (Lazma, Russia).

RESULTS

According to LDF data in both groups, it was found that the improvement of microcirculation in periodontal tissues after complex treatment is accompanied by an increase in blood flow and its activity, at that the level of oxygenation and specific oxygen consumption increased more pronounced after PDT, the effect persisted after 6 and 12 months.

CONCLUSION

The use of PDT with LED emitter has a normalizing effect on the state of microcirculation and oxygenation in periodontal tissues.

[Functional hyperemia of the periodontium during the use of chewing gum]

Functional hyperemia developing in the periodontium after 30 sec chewing of a half of a standard chewing gum plate was studied by a noninvasive quantitative method. In subjects with clinically normal periodontium and normal tonic tension of the regional vessels the peak blood flow develops within the first minute of chewing and further vasomotions restore in 30 min. In changed vascular tone, particularly so in periodontal diseases, hyperemia develops persisting for at least 30 min.

[The dynamics of functional hyperemia in the periodontium]

Time course of functional hyperemia in the periodontium was studied by quantitative rheography in 99 subjects, 55 of these presenting with periodontal diseases and 43 with clinically normal periodontium. Chewing of 5 cm3 of raw carrots for 30 sec on the working side was used as a functional exercise. In normal or reduced tone of regional vessels an oscillatory process of functional hyperemia with a latent period was developing, presumably at the expense of rise of osmotic pressure of tissue fluid. In initial vasoconstriction functional hyperemia develops without latent period and oscillatory process. A similar picture is observed in periodontal diseases, but the bloodstream volume is far less.

[Dental occlusion and pathology of periodontal inflammation]

Effect of occlusion disorders on regional circulation in periodontal tissues was studied in patients with periodontitis of medium severity. The role of selective polishing in arrest of periodontal inflammation was determined on the basis of clinical and rheoparodontographic findings. Terms and stages of selective polishing promoting redistribution of masticatory loading were determined. The effect of this procedure on microvascular tone in the periodontium, essentially affecting the course of periodontal inflammation, is discussed.

[A comprehensive study of the mechanical effects of the long-term and regular use of chewing gum]

The results of regular gum chewing (30 min 3 times a day after meals for 4 weeks) were assessed in 46 volunteers by the functional diagnosis methods. Chronometry of food chewing and arbitrary gum chewing for 30 min was carried out before the investigation. Daily duration of food chewing is about 33 min. During gum chewing, the number of masticatory strikes on the inert side is higher during the first 5 min and then levels. This leads to levelling of mechanical loading of the lateral parts of the jaws and of bioelectrical activity in the masticatory muscles proper. The gum is bit 3-5 times more often with frontal teeth than with lateral teeth. Regular use of chewing gum notably increases the blood supply to the periodontium, and the regulatory mechanisms fail to cope with it in periodontal diseases; this leads to venous congestion in the regional vascular system.

[Hemodynamic changes in the periodontium with the use of chewing gum]

The effect of gum chewing (5 min after meals 3 times a day) on periodontal blood supply was studied in a group of 52 volunteers with different clinical status of the periodontium. Tonic strain in the local vessels changed (fluctuated) little (by 2-7%). Tonic strain was shifted on the inert side and in patients with periodontal diseases. Blood consumption increased by 33%. Regular gum chewing for 10 min resulted in compensatory vasoconstriction and hyperemia of the periodontium starting from the second week, irrespective of the initial clinical status of the periodontium.

[Harmonic imaging analysis for assessment of morphological changes in mini-pig alveolar bone by normal and increased functional load]

The aim of the study was to reveal the mastication forces effect on the microstructure of mandible bone tissue of mini-pigs by Fouirier harmonic imaging analysis of bone sections images of back scattered electrons and assessment of calcium and phosphorous distribution maps obtained by roentgenofluorescence technique. The results showed that by higher functional loads not only the total content of mineral elements in the bone matrix increased but also the of the low-frequency harmonics in the image spectrum indicating structural heterogeneity decrease in bone mineralization.

[The effectiveness of photodynamic effects on the clinical and functional state of periodontal tissues in periodontitis]

The aim the study. Increasing the effectiveness of treatment of chronic generalized periodontitis of moderate severity according to microhemodynamics and oxygenation in periodontal tissues.

MATERIALS AND METHODS

A clinical and functional study and treatment of chronic generalized periodontitis of moderate degree were conducted in 56 people (22 men and 34 women) aged 37 to 55 years. The patients were divided into 2 groups depending on the type of treatment: group 1 (main) - 28 people (11 men and 17 women, the average age of the group was 43.5±2.8 years, photodynamic therapy (PDT) with 1% dimegin gel using an AFS Spectrum LED emitter with a wavelength of 660 nm and an energy density of 95 J/cm2), in group 2 (control) - 28 people. (9 men and 19 women, the average age of the group was 45.0±3.1 years) standard treatment was performed without PDT. The level of tissue blood flow, its activity and vasomotor activity of microvessels, as well as the blood flow bypass index were determined by laser Doppler flowmetry. The study of oxygenation was carried out by optical tissue oximetry with determination of the index of oxygenation, specific oxygen consumption and perfusion oxygen saturation.

RESULTS

After PDT, the periodontal tissues showed an increase in blood flow by 65.5% after 3 months, the level of oxygen metabolism increased by 51%, which increased after 6 months. The use of PDT in the complex treatment of chronic generalized periodontitis of moderate severity has an activating effect on the microcirculation system and the level of oxygen metabolism in periodontal tissues both in the near and long-term follow-up periods.

CONCLUSIONS

The use of PDT with 1% dimegin gel has an effective effect on the state of microhemodynamics and oxygenation in periodontal tissues.

[The mechanical action of Dirol chewing gum on the periodontal tissues and masticatory muscles]

Regional hemodynamics, bioelectric activity of masticatory muscles, and compactness of mandibular bone were studied by the rheographic method for measuring periodontal bloodflow, by electromyography, and echo-osteometry in 52 volunteers after 4-week regular chewing of Dirol chewing gum. Congestive hyperemia develops in periodontal tissues; functional activity of masticatory muscles and compactness of mandibular bone are normal.

[Effect of selective polishing of teeth on local circulation in prosthetic treatment by implantation]

An effect of occlusion disorders on a regional circulation was studied in periodontal tissues of abutment teeth, antagonist teeth, periimplant zone at different stages of preparation for a prosthesis by normalization of occlusion ratios by means of selective polishing of teeth. The terms and the periodicity of selective polishing promoting redistribution of the masticating pressure were determined. The connection of these factors was examined with periodontal vessel tonicity and periimplant zone on the basis of the rheoparodontographic findings.

[Use of Fourier analysis in hystomorphometry]

The mandible alveolar bone tissue of mini-pig was evaluated by means of radiospectral analysis. Fourier analysis of mineral content distribution in bone slices showed that loss of masticatory load leads to focal demineralization. With time the demineralization foci increased in amount, not in size.

[Evaluation of the photodynamic effect on the state of microcirculation and oxygenation in periodontal tissues in the treatment of chronic generalized periodontitis]

OBJECTIVE

Increasing the effectiveness of treatment of chronic generalized periodontitis using PDT based on clinical and functional substantiation of the effects of a photosensitizer.

MATERIALS AND METHODS

A clinical and functional study and treatment of moderate chronic generalized periodontitis was carried out in 62 people (26 men and 36 women) aged from 35 to 55 years without a somatic model with an orthognathic occlusion diagnosed according to ICD-10 - K05.3. Of these, 2 groups were divided depending on the type of treatment: Group 1 (main) - patients with moderate chronic generalized periodontitis - 32 people. (17 men and 15 women, average age of the group - 43.2±2.2 years); Group 2 (control) - patients with moderate chronic generalized periodontitis - 30 people. (14 men and 16 women, average age of the group - 44.0±3.3 years). Complex treatment consisted of sanitation of the mouth, removal of dental plaque and curettage of periodontal pockets in group 1, followed by PDT with Revixan gel using a special wired aligner REVIXAN DENTAL LED (16 r). The clinical condition of the periodontium was assessed using the Greene Vermillion Hygienic Index (OHI-S), the Mühlleman Bleeding Index (SBI) modified by Cowell, and the periodontal index PI. To study the state of microcirculation in the gum tissue, the laser Doppler flowmetry (LDF) method was used using the LAKK-M device (NPP «Lazma», Russia). The state of microcirculation was assessed by the microcirculation index (M), which characterizes the level of tissue blood flow; parameter - «σ», which determines the fluctuation of the erythrocyte flow. According to Wavelet analysis of LDF-grams, the shunt index (SH) of blood flow was determined. In the «LDF + spectrometry» mode, oxygenation in periodontal tissues was studied using optical tissue oximetry (OTO), based on the results of which the perfusion saturation index (Sm) and the specific oxygen consumption index (U, %) were determined.

RESULTS

According to LDF data, after PDT (group 1), normalization of clinical indices and the level of microcirculation in periodontal tissues was established, which was accompanied by an increase in the level of blood flow (M) and its activity (σ), which persisted after 3 and 6 months. after PDT. The perfusion saturation index (Sm) and specific oxygen consumption (U) increased more significantly after PDT, which persisted after 3 and 6 months. In the control group, the dynamics of indicators was less pronounced.

CONCLUSION

The use of PDT with Revixan gel normalizes the clinical condition of the periodontium, indicators of microhemodynamics and oxygen metabolism.