scholarly journals Phase Doppler Flux Comparisons

2016 ◽  
Keyword(s):  
Doppler Flux

Veränderungen der Mikrozirkulation bei Patienten mit Unterschenkelerysipelen vor, während und nach antibiotischer Therapie

Phlebologie ◽  
1998 ◽  
Vol 27 (04) ◽  
pp. 131-137
Author(s):  
S. Roszinski ◽  
W. Schmeller ◽  
S. Kock
Keyword(s):  
Laser Doppler ◽  
Doppler Flux

ZusammenfassungBei 12 Patienten mit Erysipelen am Unterschenkel erfolgten Messungen der Mikrozirkulation in Ruhe und bei hämodynamischen Funktionstests. Bestimmt wurden: Hauttemperatur, Erythemstärke (a-Wert der Colorimetrie), transkutaner Sauerstoffpartialdruck (tcPO2 bei 37° C und 44° C Elektrodentemperatur) sowie Laser-Doppler-Flux (LDF). Die Messungen wurden im Zentrum der Erysipele und an den gesunden kontralateralen Beinen zu Beginn, während und eine Woche nach Ende der Antibiotikatherapie durchgeführt. Zum Zeitpunkt der akuten Entzündung zeigten alle Parameter deutliche Veränderungen; diese wiesen Reaktionsmuster auf, wie sie auch bei Dermatosen mit morphologischen Veränderungen des Kapillarsystems gefunden werden. Nach klinischer Abheilung wiesen tcPO2 bei 37° C und Laser-Doppler-Flux sowohl in Ruhe als auch bei den Funktionstests noch deutliche Veränderungen auf.

scholarly journals Age-related differences in the cutaneous vascular response to exogenous angiotensin II

2019 ◽  
Vol 316 (3) ◽  
pp. H516-H521
Author(s):  
James A. Lang ◽  
Alex C. Krajek
Keyword(s):  
Older Adults ◽  
Angiotensin Ii ◽  
Ringer Solution ◽  
Control Site ◽  
Laser Doppler ◽  
Type Ii ◽  
Ang Ii ◽  
Age Related ◽  
Forearm Skin ◽  
Doppler Flux

Angiotensin II (ANG II) is locally produced in human skin and contributes to the reflex vasoconstriction (VC) response in aged but not young skin. We hypothesized that the exogenous ANG II-mediated VC response would be greater in older adults and would be affected by inhibition of adrenoreceptor or ANG II type II receptor (AT2R) pathways. Three microdialysis (MD) fibers were placed in the forearm skin of 11 young (26 ± 3 yr) and 11 older (68 ± 4 yr) individuals for perfusion of 1) Ringer solution (control), 2) adrenoreceptor blockade with yohimbine + propranolol, and 3) AT2R inhibition with PD-123319. ANG II was then added to the perfusates at eight graded dose concentrations ranging from 10−10 to 10−3 M. Laser Doppler flux was measured at each MD site, and cutaneous vascular conductance (CVC) was calculated as CVC =  laser Doppler flux/mean arterial pressure and normalized to baseline CVC values collected before ANG II perfusion (%ΔCVCbaseline). At the control site, older adults (−34 ± 4%ΔCVCbaseline) exhibited a greater peak VC compared with young adults (−22 ± 2%ΔCVCbaseline, P < 0.05), which was attenuated with adrenoreceptor blockade. Young skin exhibited a vasodilation in response to lower ANG II doses that was inhibited with AT2R inhibition. AT2R inhibition also increased the VC response to higher ANG II doses such that young skin responded similarly to older skin. These results indicate that ANG II has a greater VC influence in older than young individuals. Furthermore, ANG II may be affecting multiple targets, including adrenergic and AT2R pathways. NEW & NOTEWORTHY Intradermal perfusion of successive doses of angiotensin II (ANG II) revealed a role for ANG II type II receptors and dose-dependent, ANG II-mediated vasodilation in young but not older adults. In contrast, older adults exhibited greater vasoconstriction for a given dose of ANG II. The increased vasoconstriction in older adults was subsequently blunted with adrenoreceptor blockade, which indicates an interaction between ANG II and adrenergic signaling pathways in the cutaneous microcirculation.

Wavelet analysis of laser Doppler flux time series of tumor and inflammatory associated neoangiogenesis. Differences in rhythmical behavior

2009 ◽  
Vol 43 (3) ◽  
pp. 189-199
Author(s):  
Hans-Martin Häfner ◽  
Kurt Bräuer ◽  
Carolin Radke ◽  
Martin Eichner ◽  
Anke Strölin
Keyword(s):  
Time Series ◽  
Wavelet Analysis ◽  
Laser Doppler ◽  
Doppler Flux

Dynamic characteristics of laser-Doppler flux data

1999 ◽  
Vol 7 (2-3) ◽  
pp. 205-218 ◽  
Author(s):  
D. Popivanov ◽  
A. Mineva ◽  
J. Dushanova
Keyword(s):  
Dynamic Characteristics ◽  
Laser Doppler ◽  
Flux Data ◽  
Doppler Flux

Estimation of laser-Doppler flux biological zero using basilar artery flow velocity in the rabbit

1995 ◽  
Vol 268 (1) ◽  
pp. H213-H217 ◽  
Author(s):  
H. K. Richards ◽  
M. Czosnyka ◽  
P. J. Kirkpatrick ◽  
J. D. Pickard
Keyword(s):  
Flow Velocity ◽  
Laser Doppler Flowmetry ◽  
Basilar Artery ◽  
Maximum Flow ◽  
Laser Doppler ◽  
Absolute Difference ◽  
Doppler Flowmetry ◽  
Arterial Blood ◽  
Artery Flow ◽  
Doppler Flux

Laser-Doppler flowmetry has potential for continuous cerebral blood flow (CBF) measurement in man and experimental animals. However, laser-Doppler flux (LDFx) measured when perfusion is absent (the biological zero, 0biol) does not necessarily coincide with the instrument's electrical zero. To evaluate laser-Doppler flowmetry further we have compared LDFx in rabbits with continuous measurement of the maximum flow velocity (FVx) in the basilar artery using Doppler ultrasonography. Arterial blood pressure (ABP), FVx, and LDFx were measured continuously in anesthetized New Zealand White rabbits. ABP was altered by controlled hemorrhage with subsequent reinfusion. 0biol was estimated from regression analysis of FVx vs. LDFx and compared with 0biol obtained after death. There was a strong linear relationship between LDFx and FVx (r = 0.94). The absolute difference between estimated 0biol and true 0biol was 5.24% of control prehemorrhage LDFx. Variations in 0biol (range 4-409) suggest that percent changes in LDFx must be related to 0biol if results between individual animals are to be compared.

Topical Treatment of Venous Microangiopathy in Patients with Venous Ulceration with Essaven Gel

Angiology ◽  
2001 ◽  
Vol 52 (3_suppl) ◽  
pp. S29-S34 ◽  
Author(s):  
M.T. De Sanctis ◽  
L. Incandela ◽  
G. Belcaro ◽  
M.R. Cesarone
Keyword(s):  
Venous Insufficiency ◽  
Local Treatment ◽  
Venous Hypertension ◽  
Controlled Study ◽  
Control Group ◽  
Venous Ulceration ◽  
Venous Ulcers ◽  
And Control ◽  
Doppler Flux ◽  
Exchange Surface

The involvement of the microcirculation in chronic venous insufficiency (CVI), due to venous hypertension, causes venous hypertensive microangiopathy (VHM) and ulceration. VHM is char acterized by enlarged, convoluted capillaries; microvascular thrombosis; obliteration of some capillaries; increase in flux, permeability, and edema and altered microlymphatics. PO 2 is decreased and CO2 increased. Capillary exchanges are altered and nutritional alterations even tually lead to venous ulcers. Edema is associated with increased capillary pressure, reduced clearance, and increased exchange surface of capillaries, which become tortuous and glomerular-like. The aim of this randomized, placebo-controlled study was to evaluate local treatment with Essaven gel (EG) in subjects with venous microangiopathy and ulcers. Measurements of laser Doppler flux, PO2, and PCO2 in standardized conditions showed positive changes (a significant decrease of the abnormally increased flux and CO2 while PO2 increased) in the EG treatment group. Changes in the placebo and control group were more limited (changes in the placebo group were mainly associated with skin manipulation when placebo- EG was applied). In conclusion, Essaven gel, in comparison with placebo, acutely improves the microcirculation in VHM even with a single acute application.

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