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result(s) for
"Laser Doppler flowmetry"
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A randomised study of the impact of the SGLT2 inhibitor dapagliflozin on microvascular and macrovascular circulation
by
Jumar, Agnes
,
Friedrich, Stefanie
,
Bramlage, Peter
in
Aged
,
Angiology
,
Benzhydryl Compounds - pharmacology
2017
Background
The sodium–glucose cotransporter 2 inhibitor, dapagliflozin, has been shown to improve diabetic control and reduce blood pressure in patients with type 2 diabetes mellitus. Its effects on micro- and macrovascular structure and function have not yet been reported.
Methods
This was a prospective, single-centre, placebo-controlled, double-blind, randomised crossover phase IIIb study conducted between March 2014 and February 2015. After a 4-week run-in/washout phase, patients (N = 59) received 6 weeks of either dapagliflozin 10 mg or placebo once daily. They then underwent a 1-week washout before crossing over to the other treatment. Changes in retinal capillary flow (RCF) and arteriole remodelling were evaluated using scanning laser Doppler flowmetry, while micro- and macrovascular parameters in the systemic circulation were assessed using pulse wave analysis.
Results
Six weeks of dapagliflozin treatment resulted in improvements in diabetes control, including blood glucose and insulin resistance, and reduced office and 24-h ambulatory blood pressure values. RCF decreased from 324 AU at baseline to 308 AU after treatment with dapagliflozin (p = 0.028), while there was little difference after the placebo (318 AU; p = 0.334). Furthermore, the arteriole remodelling that was seen after the placebo phase was not evident after the dapagliflozin phase. Central systolic and diastolic blood pressure values were significantly lower after 6 weeks of dapagliflozin, by 3.0 and 2.2 mmHg, respectively (p = 0.035 and 0.020, respectively vs. baseline).
Conclusions
Six weeks of dapagliflozin treatment resulted in numerous beneficial effects. In addition to achieving superior diabetes control and blood pressure, parameters associated with the early stages of vascular remodelling were also improved.
Trial registration
http://www.clinicaltrials.gov
(NCT02383238)
Journal Article
Review of methodological developments in laser Doppler flowmetry
by
Steenbergen, Wiendelt
,
van Leeuwen, Ton G.
,
Varghese, Babu
in
Blood Flow Velocity - physiology
,
Circulatory system
,
Dentistry
2009
Laser Doppler flowmetry is a non-invasive method of measuring microcirculatory blood flow in tissue. In this review the technique is discussed in detail. The theoretical and experimental developments to improve the technique are reviewed. The limitations of the method are elaborated upon, and the research done so far to overcome these limitations is critically assessed.
Journal Article
Laser doppler flowmetry as a diagnostic tool to detect gingival inflammation: a systematic review
2025
Background
The aim of this systematic review was to evaluate whether laser Doppler flowmetry (LDF) as a diagnostic tool is effective in detecting gingival inflammation.
Methods
This review was conducted and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and registered at the International Prospective Register of Systematic Reviews (PROSPERO) (registration number CRD42025633576). Two authors independently performed searches in PubMed, Embase, the Cochrane Library, and Scopus.
Results
In total, 1317 studies were identified, of which 10 met the inclusion criteria after full-text screening. All studies compared perfusion with a healthy control group, seven included a gingivitis group, five included patients with periodontitis, and none included patients with peri-implant disease. Higher blood flow values were found in patients with chronic gingivitis compared to healthy controls, while patients with experimental gingivitis showed no significant difference. Blood flow values in patients with periodontitis showed controversial results.
Conclusions
LDF shows potential utility in detecting chronic gingival inflammation and altered perfusion patterns between healthy individuals and those with gingival or periodontal inflammation. However, reliably grading perfusion across disease stages and distinguishing between acute gingivitis and chronic periodontitis remains challenging. Notably, there is a lack of data regarding the use of LDF in peri-implant tissues, representing a significant gap in current research. At present, established clinical parameters such as probing depth and bleeding on probing (BOP), remain the gold standard in routine periodontal diagnostics.
Journal Article
Detection of Site-Specific Blood Flow Variation in Humans during Running by a Wearable Laser Doppler Flowmeter
2015
Wearable wireless physiological sensors are helpful for monitoring and maintaining human health. Blood flow contains abundant physiological information but it is hard to measure blood flow during exercise using conventional blood flowmeters because of their size, weight, and use of optic fibers. To resolve these disadvantages, we previously developed a micro integrated laser Doppler blood flowmeter using microelectromechanical systems technology. This micro blood flowmeter is wearable and capable of stable measurement signals even during movement. Therefore, we attempted to measure skin blood flow at the forehead, fingertip, and earlobe of seven young men while running as a pilot experiment to extend the utility of the micro blood flowmeter. We measured blood flow in each subject at velocities of 6, 8, and 10 km/h. We succeeded in obtaining stable measurements of blood flow, with few motion artifacts, using the micro blood flowmeter, and the pulse wave signal and motion artifacts were clearly separated by conducting frequency analysis. Furthermore, the results showed that the extent of the changes in blood flow depended on the intensity of exercise as well as previous work with an ergometer. Thus, we demonstrated the capability of this wearable blood flow sensor for measurement during exercise.
Journal Article
Acute effects of hypouricemia on endothelium, oxidative stress, and arterial stiffness: A randomized, double‐blind, crossover study
by
Hupkens, Emeline
,
Delporte, Cédric
,
van Antwerpen, Pierre
in
Acetylcholine
,
Acute effects
,
Adult
2021
We hypothesized acute moderate and drastic reductions in uric acid concentration exert different effects on arterial function in healthy normotensive and hypertensive adults. Thirty‐six adults (aged 58 [55;63] years) with or without primary hypertension participated in a three‐way, randomized, double‐blind, crossover study in which [placebo] and [febuxostat] and [febuxostat and rasburicase] were administered. Febuxostat and rasburicase reduce the uric acid concentration by xanthine oxidoreductase inhibition and uric acid degradation into allantoin, respectively. Endothelial function was assessed in response to acetylcholine, sodium nitroprusside, heating (with and without nitric oxide synthase inhibition) using a laser Doppler imager. Arterial stiffness was determined by applanation tonometry, together with blood pressure, renin–angiotensin system activity, oxidative stress, and inflammation. Uric acid concentration was 5.1 [4.1;5.9], 1.9 [1.2;2.2] and 0.2 [0.2;0.3] mg/dL with [placebo], [febuxostat] and [febuxostat–rasburicase] treatments, respectively (p < 0.0001). Febuxostat improved endothelial response to heat particularly when nitric oxide synthase was inhibited (p < 0.05) and reduced diastolic and mean arterial pressure (p = 0.008 and 0.02, respectively). The augmentation index decreased with febuxostat (ANOVA p < 0.04). Myeloperoxidase activity profoundly decreased with febuxostat combined with rasburicase (p < 0.0001). When uric acid dropped, plasmatic antioxidant capacity markedly decreased, while superoxide dismutase activity increased (p < 0.0001). Other inflammatory and oxidant markers did not differ. Acute moderate hypouricemia encompasses minor improvements in endothelial function, blood pressure, and arterial stiffness. Clinical Trial Registration: NCT03395977, https://clinicaltrials.gov/ct2/show/NCT03395977 Acute moderate hypouricemia encompasses minor improvements in endothelial function, blood pressure, and arterial stiffness.
Journal Article
Motion Tracking System for Robust Non-Contact Blood Perfusion Sensor
by
Hashimoto, Masaaki
,
Taguchi, Yoshihiro
in
blood perfusion
,
Electronics
,
laser Doppler flowmetry
2018
We propose a motion-robust laser Doppler flowmetry (LDF) system that can be used as a non-contact blood perfusion sensor for medical diagnosis. Endoscopic LDF systems are typically limited in their usefulness in clinical contexts by the need for the natural organs to be immobilized, as serious motion artifacts due to the axial surface displacement can interfere with blood perfusion measurements. In our system, the focusing lens moves to track the motion of the target using a low-frequency reference signal in the optical data, enabling the suppression of these motion artifacts in the axial direction. This paper reports feasibility tests on a prototype of this system using a microfluidic phantom as a measurement target moving in the direction of the optical axis. The frequency spectra detected and the perfusion values calculated from those spectra show that the motion tracking system is capable of suppressing motion artifacts in perfusion readings. We compared the prototype LDF system’s measurements with and without motion feedback, and found that motion tracking improves the fidelity of the perfusion signal by as much as 87%.
Journal Article
Forearm Skin Blood Flow After Kinesiology Taping in Healthy Soccer Players: An Exploratory Investigation
by
Hopkins, Nicola D.
,
Unnithan, Vish
,
Woodward, Kirsty A.
in
Adolescent
,
Athletic Injuries - prevention & control
,
Blood
2015
Kinesiology tape (KT) has become popular among athletes for both injury prevention and rehabilitation due to its reported therapeutic effects, including facilitation of lymphatic flow and enhanced peripheral blood flow. However, evidence to support such claims is insufficient.
To determine whether KT improves skin blood flow (SkBF) responses in young, elite soccer players.
Randomized crossover study.
Research laboratory.
Thirteen healthy, elite, adolescent male soccer players (age = 14.7 ± 0.6 years).
Participants completed 2 experimental trials; during trial 1, the volar aspect of the dominant forearm was taped. Forearm SkBF was measured within the taped area and 3 cm lateral to the taped area. During trial 2, no tape was applied to either site. Both trials were performed within 7 days.
Baseline and maximal thermally (42°C) stimulated SkBF responses were assessed using laser Doppler flowmetry. Continuously measured SkBF and derived mean arterial pressure obtained at 5-minute intervals were used to calculate cutaneous vascular conductance (CVC), the primary outcome measure.
No differences were observed for baseline SkBF or CVC between trials or measurement sites. After local heating, no differences were evident for SkBF or CVC between trials or measurement sites.
Our findings suggest that, in healthy, trained adolescent males, KT was not associated with increased forearm SkBF.
Journal Article
Evaluation of the effect of ambrisentan on digital microvascular flow in patients with systemic sclerosis using laser Doppler perfusion imaging: a 12-week randomized double-blind placebo controlled trial
by
Chatterjee, Soumya
,
Bena, James
,
Bose, Nilanjana
in
Adult
,
Aged
,
Biological products industry
2015
Introduction
In patients with systemic sclerosis (SSc), digital ischemia results from an occlusive microvasculopathy that may not respond adequately to conventional vasodilators. Endothelin receptor antagonists can potentially modify the fibroproliferative vascular remodeling in SSc, and hence their use may be justified in the management of digital ischemia. The objective of this clinical trial was to evaluate the effect of ambrisentan, a selective endothelin type A receptor antagonist, on microvascular blood flow in patients with limited systemic sclerosis (SSc) using laser Doppler perfusion imaging (LDPI).
Methods
In this randomized, double-blind, placebo controlled study we enrolled 20 patients with limited SSc. Fifteen patients received ambrisentan 5 mg daily for one month and then 10 mg daily for two months, and five received a placebo. There were three visits: weeks 0 (baseline), one and 12. Three patient-oriented questionnaires were completed at each visit: Scleroderma-Health Assessment Questionnaire (S-HAQ), Raynaud Condition Score (RCS), and Pain-Visual Analog Scale (P-VAS). At each visit, LDPI was used to obtain three blood flow readings involving regions of interest in second to fifth fingers of the non-dominant hand at room temperature (25°C) and after cooling (10°C) for two minutes.
Results
There were 16 females (80%); mean age was 50 years. None of the differences in blood flow (as measured by LDPI) were significant both at baseline and after cooling. However, patients in the ambrisentan group showed significant improvement in the patient-oriented outcomes: RCS (P = 0.001) and S-HAQ score (P = 0.005).
Conclusions
This pilot study did not show evidence of significant increase in digital blood flow over time; however, there was an improvement in RCS and S-HAQ score. We conclude that continuous use of ambrisentan for three months does not seem to significantly improve digital blood flow in SSc patients.
Trial registration
Clinicaltrials.gov
NCT01072669
. Registered 19 February 2010.
Journal Article
Laser Doppler assessment of the influence of division at the root of the inferior mesenteric artery on anastomotic blood flow in rectosigmoid cancer surgery
2007
The aim of this study is to evaluate the influence of dividing the inferior mesenteric artery (IMA) and preserving the left colic artery (LCA) on rectosigmoid cancer surgery.
Colonic blood flow at the proximal site of the anastomosis was measured by laser Doppler flowmetry in 96 patients with cancer of the rectum and sigmoid colon while clamping IMA or LCA. Results were analyzed with patient characteristics and postoperative complications.
Blood flow was significantly decreased by either IMA or LCA clamping, and its reduction rate was 38.5 +/- 1.8%, ranged from 0 to 82.8%, or 16.4 +/- 1.8%, ranged from 0 to 66.2%, respectively. For multivariate analyses, aging and male gender were predictive factors of high blood flow reduction by IMA clamping. The reduction rate was significantly correlated with aging in male patients, while no such correlation was observed in women. Aging correlation in men was more significant in ultralow anterior resection cases. Three elderly male patients received IMA high ligation among 19 patients who demonstrated more than 50% blood flow reduction by IMA clamping. Among these, two patients, those who underwent ultralow anterior resection, suffered severe anastomotic ischemia.
Colonic blood flow at the proximal site of the anastomosis was significantly decreased by either IMA or LCA clamping. Patients with high reduction by IMA clamping need intraoperative efforts to prevent anastomotic ischemia, particularly in elderly male patients who undergo ultralow anterior resection.
Journal Article
Expanding Applications, Accuracy, and Interpretation of Laser Speckle Contrast Imaging of Cerebral Blood Flow
by
Dunn, Andrew K
,
Richards, Lisa M
,
Davis, Mitchell A
in
Animals
,
Brain - blood supply
,
Cerebrovascular Circulation
2015
Laser speckle contrast imaging (LSCI) provides a rapid characterization of cortical flow dynamics for functional monitoring of the microcirculation. The technique stems from interactions of laser light with moving particles. These interactions encode the encountered Doppler phenomena within a random interference pattern imaged in widefield, known as laser speckle. Studies of neurovascular function and coupling with LSCI have benefited from the real-time characterization of functional dynamics in the laboratory setting through quantification of perfusion dynamics. While the technique has largely been relegated to acute small animal imaging, its scalability is being assessed and characterized for both chronic and clinical neurovascular imaging.
Journal Article