A characteristic feature of diabetes mellitus is an increase in blood glucose levels and the development of hyperglycemia, which provokes the development of metabolic changes at the level of cells and tissues of the body. The dysfunction of pancreatic beta cells with impaired insulin secretion and a decrease in their mass is the main sign of the development of both types of diabetes. Thus, beta cells are the main target in the development of new therapeutic approaches.
In this work, using a model of pancreatic beta cells (RINm5F), the effect of photosensitizer-free laser-induced singlet oxygen (SO) on the bioenergetics of this type of cells was studied. It was found that laser exposure affects a number of parameters characterizing the bioenergetics of cells: mitochondrial membrane potential, NADH, FAD and ATP levels. The totality of the results obtained may indicate the potential possibility of using laser-induced SO in the regulation of beta cell functions.
An approach to visualization of the vascular bed with the possibility of assessing changes in blood filling and identifying diagnostically significant periodic changes in the signal by analyzing speckle images is proposed. The effect of singlet oxygen by direct excitation of an oxygen molecule by 1267 nm laser radiation on changes in the vascular bed parameters was studied using this approach.
The paper presents the results of a study of conditionally healthy volunteers and patients with various maxillary sinuses diseases by digital diaphanoscopy with a comparison of the results obtained with CT studies. The results of the classification of pathological changes based on a quantitative assessment of the registered scattering patterns of light are also presented.
The interaction of laser radiation of wavelengths of direct optical generation of singlet oxygen with cell culture media was simulated. Using the COMSOL Multiphysics software, the distribution of the thermal field over the culture media volume was obtained depending on the wavelength, power and exposure time. The results demonstrate the importance of taking temperature into account when conducting experimental studies at the cellular and organismal levels.
In this paper the optical properties of the purulent content of the maxillary sinuses were obtained by spectrophotometry. Based on the obtained absorption and reduced scattering coefficients, a numerical simulation by Monte Carlo method was performed to determine the pattern of light scattering passing through the maxillary sinus with purulent contents. The results of the simulation showed that in transillumination methods for the detection of purulent pathological changes, it is more informative to use the radiation sources with 980 nm.
Digital diaphanoscopy method has potential to separate normal and pathological conditions of the maxillary sinuses. The entirety of all the features of the investigated area (the presence or absence of pathology, its etiology and morphological features) affects the resulting images of the maxillary sinuses by the digital diaphanoscopy. In this work, the MonteCarlo numerical simulation method was used to determine the patterns of propagation of light radiation in biological tissue. A biologically heterogeneous environment, represented by structures of the skull and maxillary sinuses, as well as pathological changes in them was modelled in the TracePro software.
The digital diaphanoscopy method seems promising for solving one of the urgent problems of modern otolaryngology, which is associated with providing accurate, painless and timely diagnosis of pathologies of the maxillary sinuses. Optical properties of the study area and their changes for different anatomical and gender features and pathologies presence determine the results of digital diaphanoscopy. Adjusting the parameters of the probing and measuring parts of digital diaphanoscopy devices taking into account these factors is important task to obtain similar light scattering patterns for different patients and the possibility of their subsequent comparison.
This paper presents the improved numerical model of the maxillary sinuses. The developed model considered the maxillary sinuses sizes, their location and asymmetry, various thicknesses of bone and soft tissues, size and localization of pathology (cystic fluid and tumor). The cross-sectional face model was more detailed and considered the curvature of the face. Simulation was carried out at various positioning of radiation source relative to the study area and detector. Additionally, the various rotation angles of the study area with radiation source relative to the detector were considered. The attenuation of probe radiation intensity at the detector was estimated using the Monte Carlo method in the TracePro (Lambda Software) for visible and near-IR wavelengths at the different intensity values.
The correlations between model signal and anatomical features of the study area, and the changes of the study area position were identified. It was established that registration of light scattering patterns at different position is important parameter for more accurate evaluation of the maxillary sinuses state and the localization of pathologies. The threshold values of the probe radiation intensity and the optimal study positions, which provide the optimal signal-to-noise ratio of the detectable signals, were identify.
Diagnosis of inflammatory diseases of the paranasal sinuses is one of the urgent problems of modern otolaryngology. Presently, radiography, computed tomography, magnetic resonance imaging, rhinoscopy and ultrasound are used to identify these pathologies. However, due to use of carcinogenic roentgen radiation during the study, a high level of falsenegative results and painfulness of the diagnostic procedures, application of these methods is limited. To overcome these shortcomings, the application of the digital diaphanoscopy method seems to be promising. For realization of this approach the experimental setup was designed and assembled. Low-intensity radiation of the visible and near IR ranges and CMOS-camera were used for translucence of the paranasal sinuses and visualizing the pattern of scattering light. To identify the range of exposure values of the CMOS-camera to obtain maximum sensitivity to identify of pathological changes, experimental studies were conducted on healthy volunteers and patients with inflammatory diseases of paranasal sinuses. During the studies the exposure time of CMOS-camera changed in the range from 0 to 39.7 ms with a step of 1 ms, followed by comparison of the results of digital diaphanoscopy with results of MRI. The results of study 20 volunteers and 15 patients of different genders and ages showed variations in the scattering patterns with the same exposure time. This was explained by such anatomic features as the structure of the skin, the thickness of the skull bone tissue, the size of the sinuses and their asymmetry.
Videocapillaroscopy (VCS) and laser Doppler flowmetry (LDF) are non-invasive methods for evaluating microcirculation parameters. The VCS method is based on a high-speed video recording of capillaries in the nailfold. The recorded video frames are processed using a specialized algorithm to determine the red blood cells velocity. The LDF technique is based on the analysis of the Doppler shift of back-scattered laser radiation from moving red blood cells. In this work, simultaneous measurements of VCS and LDF have been performed in healthy volunteers and rheumatic patient. The study was conducted using a cold pressor test. Changes were recorded in response to cold exposure in rheumatic diseases.
Laser Doppler flowmetry (LDF) was utilized for blood ow measurements. Wavelet analysis was used to identify spectral characteristics of the LDF signal in patients with rheumatic diseases and diabetes mellitus. Baseline measurements were applied for both pathological groups. Blood flow oscillations analyses were performed by means of the wavelet transform.
Higher baseline perfusion was observed in both pathological groups in comparison to controls. Differences in the spectral properties between the groups studied were revealed. The results obtained demonstrated that spectral properties of the LDF signal collected in basal conditions may be the signature of microvasculature functional state.
Laser Doppler flowmetry (LDF), tissue reflectance oximetry (TRO) and pulse oximetry (PO) and cold pressor test (CPT) were used to assess the microcirculation parameters and the activation of regulatory mechanisms. LDF and TRO samples wavelet transform in the frequency bands 0.01-2 Hz was used to evaluate microvascular disturbances in rheumatic diseases and to assess the vascular involvement in the pathological process. The spectral components of LDF and TRO signals associated with endothelial, adrenergic, intrinsic smooth muscle, respiratory and cardiac activities were analyzed. Significant difference between healthy and rheumatology subjects was identified in perfusion parameters. Spectral analysis of the LDF signal revealed significant difference between two group of high (<0.1 Hz) frequency pulsations. Based on the analysed of the perfusion and amplitudes oscillation in the frequency band the decision rule for detection microvascular disturbances were synthesized. The perfusion parameter and amplitude oscillation associated with cardiac activities included in the decision rule. Based on the measured parameters and the result of wavelet transform LDF- and TRO-signals the parameters for detection of complications associated with microvascular disturbances and their possible causes were proposed..
According to the International Diabetes Federation, the challenge of early stage diagnosis and treatment effectiveness monitoring in diabetes is currently one of the highest priorities in modern healthcare. The potential of combined measurements of skin fluorescence and blood perfusion by the laser Doppler flowmetry method in diagnostics of low limb diabetes complications was evaluated. Using Monte Carlo probabilistic modeling, the diagnostic volume and depth of the diagnosis were evaluated. The experimental study involved 76 patients with type 2 diabetes mellitus. These patients were divided into two groups depending on the degree of complications. The control group consisted of 48 healthy volunteers. The local thermal stimulation was selected as a stimulus on the blood microcirculation system. The experimental studies have shown that diabetic patients have elevated values of normalized fluorescence amplitudes, as well as a lower perfusion response to local heating. In the group of people with diabetes with trophic ulcers, these parameters also significantly differ from the control and diabetes only groups. Thus, the intensity of skin fluorescence and level of tissue blood perfusion can act as markers for various degrees of complications from the beginning of diabetes to the formation of trophic ulcers.
Laser Doppler flowmetry (LDF) has been applied for the assessment of variation in blood microflows in patients with rheumatic diseases and healthy volunteers. Oscillations of peripheral blood microcirculation observed by LDF have been analyzed utilizing a wavelet transform. A higher amplitude of blood microflow oscillations has been observed in a high frequency band (over 0.1 Hz) in patients with rheumatic diseases. Oscillations in the high frequency band decreased in healthy volunteers in response to the cold pressor test, whereas lower frequency pulsations prevailed in patients with rheumatic diseases. A higher perfusion rate at normal conditions was observed in patients, and a weaker response to cold stimulation was observed in healthy volunteers. Analysis of blood microflow oscillations has a high potential for evaluation of mechanisms of blood flow regulation and diagnosis of vascular abnormalities associated with rheumatic diseases.
The aim of this work was to study the possibilities of the laser Doppler flowmetry method for the joint study of microhaemo- and lymph circulation of human skin.
Conducting a series of experimental studies allowed to trace the relationship of recorded signals of microcirculation of blood flow and lymph flow, as well as to study their oscillation nature by using wavelet analysis.
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