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.
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.
This study examines the effect of blood absorption on the endogenous fluorescence signal intensity of biological tissues. Experimental studies were conducted to identify these effects. To register the fluorescence intensity, the fluorescence spectroscopy method was employed. The intensity of the blood flow was measured by laser Doppler flowmetry.
We proposed one possible implementation of the Monte Carlo method for the theoretical analysis of the effect of blood on the fluorescence signals. The simulation is constructed as a four-layer skin optical model based on the known optical parameters of the skin with different levels of blood supply. With the help of the simulation, we demonstrate how the level of blood supply can affect the appearance of the fluorescence spectra.
In addition, to describe the properties of biological tissue, which may affect the fluorescence spectra, we turned to the method of diffuse reflectance spectroscopy (DRS). Using the spectral data provided by the DRS, the tissue attenuation effect can be extracted and used to correct the fluorescence spectra.
Skin blood microcirculation and the metabolism activity of tissue were examined on the patients with type 2 diabetes. Laser Doppler flowmetry (LDF) with 1064 nm laser light source and fluorescence spectroscopy (FS) with excitation light of 365 nm and 450 nm have been used to monitor the blood perfusion and the content of coenzymes NADH and FAD. Concluding, the proposed combined LDF and tissue FS approach allows to identify the significant violations in the blood microcirculation and metabolic activity for type 2 diabetes patients.
Endothelial dysfunction is directly linked to preeclampsia, a maternal hypertensive condition that is life
threating for both the mother and the baby. Epidemiological studies show that women with a history of pre-eclampsia
have an elevated risk for cardiovascular disease. Here we report a new non-invasive diagnostic test for preeclampsia in
mice that allows us to non-invasively assess the condition of the animals during the experiment and treatment in
established models of preeclampsia. A laser-based multifunctional diagnostics system (LAKK-M) was chosen to carry
out non-invasive analysis of multiple parameters. The device was used to simultaneously record the microcirculatory
blood flow and oxygen saturation, as well as fluorescence levels of endogenous fluorophores. Preliminary experiments
were conducted on adenoviral (Ad-)- mediated overexpression of sFlt-1 (Ad-sFlt-1) to mimic preeclampsialike
symptoms in mice. The recorded data displayed the ability of the LAKK-M diagnostics device to detect significant
differences in perfusion measurements between the control and Ad-sFlt-1 treatment. Preliminary results provide a
potential avenue to employ these diagnostics technology to monitor and aid in maintaining control of live animal
conditions throughout the experiment and treatment.
Urinary bladder diseases are a common problem throughout the world and often difficult to accurately diagnose. Furthermore, they pose a heavy financial burden on health services. Urinary bladder tissue from male pigs was spectrophotometrically measured and the resulting data used to calculate the absorption, transmission, and reflectance parameters, along with the derived coefficients of scattering and absorption. These were employed to create a “generic” computational bladder model based on optical properties, simulating the propagation of photons through the tissue at different wavelengths. Using the Monte-Carlo method and fluorescence spectra of UV and blue excited wavelength, diagnostically important biomarkers were modeled. Additionally, the multifunctional noninvasive diagnostics system “LAKK-M” was used to gather fluorescence data to further provide essential comparisons. The ultimate goal of the study was to successfully simulate the effects of varying excited radiation wavelengths on bladder tissue to determine the effectiveness of photonics diagnostic devices. With increased accuracy, this model could be used to reliably aid in differentiating healthy and pathological tissues within the bladder and potentially other hollow organs.
Fluorescent spectroscopy (FS) is becoming more widely used in chemistry, biology, in various fields of medical technology and medicine in general. Many purulent wounds, burns and other destructive inflammatory processes are accompanied by changes in the fluorescent activity of the tissues, which occurs due to a misbalance in accumulation of natural fluorophores: FAD, NADH, lipofuscin, porphyrins, structural proteins, etc. The study of redox ratio (RR), characterizing the metabolic processes, is important in the assessment of the metabolic activity ofmicrocirculatory-tissue systems (MTS). However, one of the big problems of the FS method is still the correct interpretation of the data and the development of practical methods for its application in clinical medicine. To solve this problem and create new diagnostic criteria, we propose to evaluate the adaptive capacity of MTS using indicators of links between nutritive blood flow and redox ratio during a physiological rest and functional load (occlusion test). As is known, these parameters (RR and nutritive blood flow) characterize the metabolic activity of tissues.We have performedan experimental study of the relationship between the RR, defined by FS, and nutritive blood flow, defined by the methods of laser Doppler flowmetry. Preliminary results in the study of a complex approach to diagnosis of the state of biological tissue were obtained. A positive relationship between the nutritive blood flow in the microcirculatory channel and RR of skin tissue is observed.The speed of change of metabolism in the phase of occlusion and reperfusion and duration of phase of recovery may be the criteria for adaptive capabilities of MTS, which has practical significance for physiology and medicine.
Diseases of urinary bladder are a common healthcare problem world over. Diagnostic precision and predicting response to treatment are major issues. This study aims to create an optical cross-sectionional model of a bladder, capable of visually representing the passage of photons through the tissue layers. The absorption, transmission and reflectance data, along with the derived transmission coefficients (of scattering and absorption) were obtained from literature analysis and were used in the creation of a “generic” cross-section optical property model simulating the passage of thousands of photons through the tissue at different wavelengths. Fluorescence spectra of diagnostically relevant biomarkers excited by the UV and blue wavelengths were modelled on the basis of the Monte-Carlo method. Further to this, fluorescence data gathered by the “LAKK-M” system from pig bladders was applied to the model for a specific representation of the photon passage through the tissues. The ultimate goal of this study is to employ this model to simulate the effects of different laser wavelength and energy inputs to bladder tissue and to determine the effectiveness of potential photonics based devices for the diagnosis of bladder pathologies. The model will aid in observing differences between healthy and pathological bladder tissues registered by photonics based devices.
Bladder cancer is among the most common cancers worldwide (4th in men). It is responsible for high patient morbidity
and displays rapid recurrence and progression. Lack of sensitivity of gold standard techniques (white light cystoscopy,
voided urine cytology) means many early treatable cases are missed. The result is a large number of advanced cases of
bladder cancer which require extensive treatment and monitoring. For this reason, bladder cancer is the single most
expensive cancer to treat on a per patient basis. In recent years, autofluorescence spectroscopy has begun to shed light
into disease research. Of particular interest in cancer research are the fluorescent metabolic cofactors NADH and FAD.
Early in tumour development, cancer cells often undergo a metabolic shift (the Warburg effect) resulting in increased
NADH. The ratio of NADH to FAD (“redox ratio”) can therefore be used as an indicator of the metabolic status of cells.
Redox ratio measurements have been used to differentiate between healthy and cancer breast cells and to monitor cellular
responses to therapies. Here, we have demonstrated, using healthy and bladder cancer cell lines, a statistically significant
difference in the redox ratio of bladder cancer cells, indicative of a metabolic shift. To do this we customised a standard
flow cytometer to excite and record fluorescence specifically from NADH and FAD, along with a method for
automatically calculating the redox ratio of individual cells within large populations. These results could inform the
design of novel probes and screening systems for the early detection of bladder cancer.
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