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Fluorescent Technology in the Assessment of Metabolic Disorders in Diabetes
Published in Andrey V. Dunaev, Valery V. Tuchin, Biomedical Photonics for Diabetes Research, 2023
Elena V. Zharkikh, Viktor V. Dremin, Andrey V. Dunaev
To determine the prospects for the joint application of fluorescence spectroscopy and laser Doppler flowmetry methods in identifying the presence and severity of diabetic complications, experimental studies were carried out. The method of laser Doppler flowmetry allows noninvasive diagnostics of the state of blood microcirculation and has been used for many years in various fields of medicine. The choice of this method as an adjunct to fluorescence in this study was due to the fact that microcirculation disorders in diabetes are closely associated with metabolic disorders.
Control of Regional Circulations During Dynamic Exercise
Published in Irving H. Zucker, Joseph P. Gilmore, Reflex Control of the Circulation, 2020
About half of the reflex vasoconstriction in the forearm with leg exercise is attributable to skin and the rest is attributable to muscle, as demonstrated by techniques which, when combined with venous occlusion plethysmography (Bevegard and Shepherd, 1967), permit separation of the two beds. Quantification of increases in forearm skin blood flow is simpler because the increments are confined to skin (at least muscle blood flow does not increase) and the absolute changes are large. Recent advances in assessing relative changes in skin blood flow by laser-Doppler flowmetry have largely confirmed plethysmographic measurements, and have also added new information (Johnson, 1986).
Pancreas Microcirculation
Published in John H. Barker, Gary L. Anderson, Michael D. Menger, Clinically Applied Microcirculation Research, 2019
Michael D. Menger, Brigitte Vollmar
The accuracy of the technique used for the study of the microcirculation, the variations in the surgical preparations, and, undoubtedly, the complexity/variations in vascular supply influence the measurements of nutritional perfusion of the pancreas. Tissue perfusion in the gland can be assessed qualitatively by thermocouples, and quantitatively by isotope fractionation, distribution of microspheres, hydrogen desaturation, and clearance of either xenon or krypton (reviewed in Reference 36). In addition, laser Doppler flowmetry represents a valuable, noninvasive tool for the assessment of microvascular perfusion, allowing for repeated/continuous measurements over a prolonged period of time. However, intravital microscopy is the only technique that provides direct access to the microcirculation. Visualization of the individual segments of the microcirculation, i.e., arterioles, capillaries and postcapillary and collecting venules of both acinar and insular tissue, allows for repeated/continuous analyses of dynamic processes, such as red blood cell velocity and flux, vessel diameter, and capillary density.1,19,35 In addition, the technique allows for the assessement of cell-cell interaction, including leukocytes, thrombocytes, and endothelial cells. In vivo microscopy may be applied not only for the study of the microcirculation of native exocrine and endocrine tissue, but also in malignant and nonmalignant pancreatic tumors as well as pancreatic and islet transplants.
Resting heart rate predicts cardiac autonomic modulation during passive head-up tilt in subjects without cardiovascular diseases
Published in Scandinavian Cardiovascular Journal, 2022
Jenni K. Koskela, Anna Tahvanainen, Antti J. Tikkakoski, Pauliina Kangas, Marko Uitto, Jari Viik, Mika Kähönen, Jukka Mustonen, Ilkka Pörsti
All of the present participants were without signs of cardiovascular autonomic dysfunction, which has been previously related, e.g. to autoimmune and neurological diseases and acute myocardial infarction [32]. It seems likely that mean HR and HRV are well correlated in healthy subjects, while depressed HRV and low LF/HF ratio have been observed in patients in the acute phase of myocardial infarction [32]. Altogether, autonomic dysfunction has been associated with increased time-varying cardiovascular complexity [47]. Autonomic control of peripheral vascular tone was not examined in our study that focused on cardiac autonomic modulation using HRV [46]. Simultaneous recordings of photoplethysmograms [48,49] and blood pressure from fingers have indicated that the low-frequency component of photoplethysmogram variability may reflect the autonomic control of blood pressure [49]. Laser doppler flowmetry would offer an alternative method for blood flow measurements in tissues [50]. Recently, models for the study of complex dynamics in autonomic control during the tilt-test have also been published [51].
Mechanism of Huangqi–Honghua combination regulating the gut microbiota to affect bile acid metabolism towards preventing cerebral ischaemia–reperfusion injury in rats
Published in Pharmaceutical Biology, 2022
Kai Wang, Yue Chen, Jinyi Cao, Ruimin Liang, Yi Qiao, Likun Ding, Xiaojuan Yang, Zhifu Yang
The SD rats were anaesthetized with 3% sodium pentobarbital. The body temperature of rats was maintained at approximately 37 °C during the operation until anaesthesia. The CI/RI model was adapted from Longa et al. (1989) and Koizumi et al. (1986). The left common carotid artery (CCA), external carotid artery (ECA), and internal carotid artery (ICA) were separated by operation. The CI/RI model was established by inserting a nylon wire (approximately 1.8 cm) from the CCA to the ICA, avoiding the pterygopalatine artery. Laser Doppler Flowmetry was used to monitor cerebral blood flow. After inserting the nylon wire, the ICA was ligated to complete the ipsilateral ischaemia. After 2 h of ischaemia, the nylon wire was gently pulled out to form reperfusion. The wound was disinfected with iodine and then sutured.
The shadow zone of capillaroscopy in the classification of the Raynaud’s phenomenon
Published in Current Medical Research and Opinion, 2022
Maria Maddalena Sirufo, Lina Maria Magnanimi, Lia Ginaldi, Massimo De Martinis
Similarly, Ingegnoli et al. refer to suspected secondary RP in RP associated with abnormal capillaroscopy and/or ANA positivity with physical findings or symptoms suggestive of secondary causes but not fulfilling criteria for a specific connective tissue disease2. In this context it is also important to underline that to study the structure and function of the finger microvasculature in patients with RP, different diagnostic imaging techniques are available. Among these, videocapillaroscopy, dermoscopy, stereomicroscopy, digital USB microscopy are four different nailfold capillaroscopy methods. Then, four laser Doppler methods are available: laser Doppler flowmetry, imaging, anemometry/velocimetry and laser speckle contrast analysis and still thermographic imaging and upper limb arterial Doppler ultrasound. However, techniques other than capillaroscopy are currently little used and confined to specialist centers17. Furthermore, emerging, new diagnostic techniques may help to reliably discriminate between primary and secondary Raynaud’s phenomenon18. However some shadows remain in the classification of RP and perhaps only two categories are not sufficient to define such a varied syndrome.