ISSN:0309-1902    

DOI:10.3109/03091909009009954

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

Laser Doppler flowmetry (LDF) is now a well-established, noninvasive technique for measuring microvascular blood perfusion. However, there are a number of factors which can seriously affect the interpretation of the laser Doppler signal which are often not considered during routine use. These include: consideration of signal processing limitations, choice of processing bandwidth, problems with motion artefact and instrument calibration, the effect of probe pressure on the skin, and the type of laser used. This paper reviews many of the problems and limitations frequently encountered using the laser Doppler technique.

ISSN:0309-1902    

DOI:10.3109/03091909009009955

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

In a retrospective study of critical ischaemia of the lower limb, sympathectomy appeared to be of value in the majority of patients. We therefore assessed sympathectomy by measuring skin blood flow before and after the procedure using laser Doppler flowmetry (LDF) and transcutaneous oxygen tension (TCpO2) techniques. Twenty patients underwent chemical sympathectomy and there was one surgical procedure. Measurements were performed before and 1 week after sympathectomy below the knee and on the forefoot. Symptomatic improvement occurred in 20 of 21 patients. This study demonstrates that skin blood flow in the leg and foot is improved by sympathectomy and confirms objectively our clinical impression.

ISSN:0309-1902    

DOI:10.3109/03091909009009956

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

White blood cells have recently been implicated in the development of venous ulceration. Fifty subjects (14 normal controls, 21 with superficial venous insufficiency (SVI), and 15 with deep venous insufficiency (DVI)) have been studied in the supine and dependent positions in a constant environment using video capillary microscopy, laser Doppler flowmetry and transcutaneous oxygen measurements to the gaiter skin.All three groups had an increase in visible capillary loops and a reduction in blood flux in the gaiter region when the leg was placed in the dependent position. There was a decrease in the leg/chest transcutaneous oxygen ratio in all three groups on dependency.These results suggest that the‘oedema protection reflex’(as measured by the laser Doppler probe) is present not only in normal and SVI limbs but also in DVI limbs. The increase in visible capillary loops suggests that intraluminal capillary occlusion is not occurring within the period of this study. The exact microvascular defecit of venous ulceration remains to be explained.

ISSN:0309-1902    

DOI:10.3109/03091909009009957

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

We have used laser Doppler flowmetry to assess human colonic blood flow in patients with healthy mucosa and in those with active proctitis. We report a significant correlation between colonic serosal laser Doppler flux readings and serosal tissue oxygen tension (n = 45: r = 0–671: p = 0–001). Mucosal blood flow was measured using the PF309 probe of a Perimed Pf2b set on 12 kHz frequency shift. There was no significant difference throughout the colon in healthy patients. The flow in rectal mucosa was significantly higher in patients with proctocolitis than in normal mucosa.

ISSN:0309-1902    

DOI:10.3109/03091909009009958

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

Intradermal injections of normal saline and different concentrations of bradykinin were made into the forearms of healthy volunteers. Cutaneous blood flow was recorded just outside and over the centre of the weals by laser Doppler flowmetry (LDF), and flare area and weal volume were measured. There were concentration-related changes in the mean LDF output adjacent to the weal, flare area and weal volume. LDF recordings performed over the centre of the weals, however, failed to show any dose-response relationship. When similar concentrations of bradykinin were injected intradermally and the skin response measured by the above parameters, there was less variation in the mean LDF output adjacent to the weal than flare or weal measurements. The non-invasive technique of LDF is a useful, objective and sensitive technique of quantifying the skin blood flow changes induced by intradermal bradykinin and provides an alternative method of quantifying skin response to intradermal bradykinin to measurement of flare or weal sizes.

ISSN:0309-1902    

DOI:10.3109/03091909009009959

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

A modified method for quantitative measurement of nociceptor C fibre function is described. The electrophoresis of acetylcholine stimulates C fibres to produce an axon reflex flare which is measured by laser Doppler flowmetry. The use of the dorsal, rather than the plantar, surface of the foot at a skin temperature of 32–33°C rather than 34–35°C improves the sensitivity of the technique. Acetylcholine produces an earlier and more predictable response than normal saline, which is approximately half maximal at a current of 0.2 mA and maximal at 1.0 mA. The use of different current strengths should allow more detailed assessment of neurogenic inflammation and the effects of drugs and disease states on C fibre function.

ISSN:0309-1902    

DOI:10.3109/03091909009009960

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

A comparison was made of the vascular actions of two hormones having a renal site of action, angiotensin II and vasopressin, using laser Doppler flowmetry to measure perfusion of the cortical and papillary regions of the kidney. Angiotensin II infusion caused dose-related increases in blood pressure and reductions in cortical perfusion, the latter responses being potentiated in the presence of the converting enzyme inhibitor, cilazapril. However, angiotensin II had no effect on papillary perfusion either before or following cilazapril. The reasons for this differing vasoconstrictor ability of angiotensin II at the cortex and papilla are unclear, but it could be due to medullary generation of prostaglandin or bradykinin. Administration of equipressor doses of vasopressin caused graded reductions in both‘cortical and papillary perfusions, and subsequent cilazapril significantly enhanced the papillary responses. This study demonstrates that the regulation of blood flow through the different regions of the kidney can be differentially regulated by the peptide hormones angiotensin II and vasopressin.

ISSN:0309-1902    

DOI:10.3109/03091909009009961

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

A preparation of an isolated bovine forefoot was established which could be perfused with blood al variable rates. A laser Doppler flowmeter probe inserted into the cancellous bone of the metatarsal produced a signal which varied with changes in perfusion rale and oscillated in synchrony with the peristaltic perfusion pump.A stronger laser Doppler signal was obtained when the probe was inserted into a drill hole than when inserted into a hole bored with a guide wire.It appears that laser Doppler flowmetry has potential intraoperative use when the viability of bone is in question.

ISSN:0309-1902    

DOI:10.3109/03091909009009962

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor

摘要:

Blood vessels of the yolk sac membrane are the transport route by which a chick embryo obtains nutrients from the egg yolk. After 4 days of incubation at 3T°C a sparse network of blood vessels are visible within the membrane and they become denser over the following days.The preparation has been used to assess angiogenesis. Using visual inspection to assess the growth of new vessels towards pellets of test substances placed on the membrane surface, responses are judged negative or positive.Laser Doppler flowmetry has been used to investigate the potential of this technique to quantify blood flow through the yolk sac membrane. Measurements have been taken from capillary beds and single larger vessels over a range of temperatures and from avascular yolk and egg white using a Perimed PF3 with PF310 bent-tipped probe. Capillary beds exhibited vasomotion (about one cycle per minute) and oscillations of longer duration (about five cycles per hour). Cardiac pulses, strongly present in larger vessels (mean 90 pu, pulse 75 pu), were not easily identified in the capillary bed. Avascular yolk measurements gave flux values (due to Brownian motion of yolk proteins) which were greater than for capillary beds but without oscillations.Angiogenesis was stimulated by pellets containing 2 fig of basic fibroblast growth factor. There were significant increases in single vessel blood flow after 24 h compared with blank control pellets placed on the same egg.

ISSN:0309-1902    

DOI:10.3109/03091909009009963

出版商:Taylor&Francis    

年代:1990

数据来源: Taylor