Objective: To evaluate the dynamics of skin microvascular blood flow (BF) and tissue oxygenation parameters (OXY) measured simultaneously at the same site using a combined non-invasive BF+OXY+temperature probe.
Methods: Skin BF, oxygenated (oxyHb) and deoxygenated (deoxyHb) haemoglobin and mean oxygen saturation (SO2 ) were measured in 50 healthy volunteers at rest and during perturbation of local blood flow by post-occlusive reactive hyperaemia, sympathetic nervous system-mediated vasoconstriction (deep inspiratory breath-hold) and local skin warming. Signals were analysed in time and frequency domains.
Results: The relationship between BF and SO2 over the range of flows investigated was described by a non-linear equation with an asymptote for SO2 of 84% at BF >50 PU. SO2 was independently associated with BF, skin temperature, BMI and age, which together identified 59% of the variance in SO2 (p<0.0001). Fourier analysis revealed periodic low frequency fluctuations in both BF and SO2 , attributable to endothelial (~0.01 Hz), neurogenic (~0.04 Hz) and myogenic (~0.1 Hz) flow motion activity. The frequency coherence between the BF and SO2 signals was greatest in the endothelial and neurogenic frequency bands.
Conclusions: The simultaneous evaluation of microvascular blood flow and oxygenation kinetics in healthy skin provides a platform from which to investigate microvascular impairment in the skin and more generally the pathogenesis of microvascular disease.
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http://dx.doi.org/10.1111/micc.12136 | DOI Listing |
Int J Numer Method Biomed Eng
January 2025
College of Chemistry and Life Science, Beijing University of Technology, Beijing, China.
The accurate non-invasive detection and estimation of central aortic pressure waveforms (CAPW) are crucial for reliable treatments of cardiovascular system diseases. But the accuracy and practicality of current estimation methods need to be improved. Our study combines a meta-learning neural network and a physics-driven method to accurately estimate CAPW based on personalized physiological indicators.
View Article and Find Full Text PDFJ Neuroendocrinol
January 2025
Department of Psychology, Columbia University, New York, New York, USA.
Among contributors to diffusible signaling are portal systems which join two capillary beds through connecting veins. Portal systems allow diffusible signals to be transported in high concentrations directly from one capillary bed to the other without dilution in the systemic circulation. Two portal systems have been identified in the brain.
View Article and Find Full Text PDFJ Neurosci Res
January 2025
Luhe Institute of Neuroscience, Capital Medical University, Beijing, China.
Despite significant advancements in achieving high recanalization rates (80%-90%) for large vessel occlusions through mechanical thrombectomy, the issue of "futile recanalization" remains a major clinical challenge. Futile recanalization occurs when over half of patients fail to experience expected symptom improvement after vessel recanalization, often resulting in severe functional impairment or death. Traditionally, this phenomenon has been attributed to inadequate blood flow and reperfusion injury.
View Article and Find Full Text PDFFront Med (Lausanne)
December 2024
Department of Medical Ultrasound, Jinshan Hospital of Fudan University, Shanghai, China.
Purpose: Acute fatty liver of pregnancy (AFLP) is a severe complication that can occur in the third trimester or immediately postpartum, characterized by rapid hepatic failure. This study aims to explore the changes in portal vein blood flow velocity and liver function during pregnancy, which may assist in the early diagnosis and management of AFLP.
Methods: This longitudinal study was conducted at a tertiary healthcare center with participants recruited from routine antenatal check-ups.
Front Pharmacol
December 2024
Department of Radiology, Tianjin Key Laboratory of Functional Imaging and Tianjin Institute of Radiology, Tianjin Medical University General Hospital, Tianjin, China.
Introduction: Although photodynamic therapy (PDT) shows considerable potential for cancer treatment due to its precise spatial control and reduced toxicity, effectively eliminating residual cells under hypoxic conditions remains challenging because of the resistance conferred by these cells.
Methods: Herein, we synthesize an amphiphilic PEGylated polyphosphoester and present a nanocarrier (NP) specifically designed for the codelivery of hydrophobic photosensitizer (chlorin e6, Ce6) and hypoxia-activated prodrugs (tirapazamine, TPZ). We investigate the antitumor effect of NP on both cellular and animal level.
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