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PubMedDate not supplied

[Measurement of cutaneous blood flow by laser Doppler velocimetry. Importance of probe effect and solvent effect after topical application].

A comparative methodological study of the probe and/or vehicle effects was performed in Human volunteers with two laser Doppler velocimeters (L.D.V.): Laserflo BPM 403, T.S.I., U.S.A. and Periflux PF2B, Perimed, Sweden. Individual variations of skin blood flow are great (up to 1,400%); this could be related to spontaneous variations and/or to the occlusive effect of the probe. Skin blood flow was significantly increased in 35% of the subjects after the application of the probe alone, and in 70 to 90% of the cases after topical application of water or ethanol (20 to 50 microliters). Lag times before vasodilatation measured only when the probe was applied on the skin were between 7.4 and 27 minutes, they were reduced between 5.2 and 8.3 minutes when the vehicles were applied. These data suggest that in any protocol for L.D.V. determination an absolute control and a vehicle control should be included to evaluate objectively topical vasoactive drugs.

Administration, Topical↗
PubMed1993

Effects of oxygen and carbon dioxide on human retinal circulation.

PURPOSE: Carbogen, a gas mixture of 95% O2 and 5% CO2, is given to patients with retinal artery obstruction in an attempt to improve retinal oxygenation. The purpose of this study was to compare the effects of carbogen and 100% O2 breathing on retinal blood flow. METHODS: On two separate occasions, 12 normal, healthy volunteers breathed air and then either 100% O2 or carbogen while laser Doppler velocimetry measurements and monochromatic fundus photographs were taken. Retinal vessel diameter, maximum velocity of red blood cells, and volumetric blood flow rate were determined in a main temporal vein. RESULTS: Both 100% O2 and carbogen caused significant average reductions in vessel diameter (14.1% and 10.6%, respectively), maximum red blood cell velocity (42.1% and 27.3%, respectively), and blood flow (56.4% and 42.2%, respectively). The average vasoconstriction of the large retinal veins caused by carbogen was not significantly smaller than that caused by 100% O2. The average reductions in maximum red blood cell velocity and blood flow caused by carbogen were significantly smaller than those caused by 100% O2 (P < .001 and P < .01, respectively). CONCLUSIONS: In normal subjects, inhalation of carbogen leads to less reduction in blood flow than inhalation of 100% O2, presumably by reducing the vasoconstriction of small arterioles induced by elevated oxygen levels.

Adult↗
PubMedDate not supplied

[Instrumental research of the functional character of the skin adnexa and microcirculation during chronic venous insufficiency].

We have led a microcirculatory and functional research of skin adnexa over 3 groups of 20 people each, who were affected with IVC at different grades and we have compared them to another group of 20 normal people. The microcirculatory researches (laser-Doppler, skin oximetry and thermometry) and functional ones of skin adnexa (sebometry and skin hydration) allowed us to get a nonunivocal behaviour between normal subjects and phlebopathies of I degree. For this reason, it is possible to consider these exams as screenings tests to determine the starting phases of phlebopathy, failing any skin marks. The reduced fluximetrical response taken by laser Doppler after postural variation and the reduction of hydration degree have been considered particularly significant.

Blood Gas Monitoring, Transcutaneous↗
PubMed1993

Sequential measurements of cerebral blood flow in the acute phase of subarachnoid hemorrhage.

Cerebral blood flow (CBF) measurements were made at predetermined intervals over the first 20 days after a subarachnoid hemorrhage (SAH) by the method of 133Xe inhalation clearance in 39 patients, Hunt and Hess degrees I, II or III. Mean hemispheral and regional blood flow showed a similar pattern of behavior over time: namely an initial hypoperfusion, being more marked in patients with consistent or thick blood deposition at CT scanning, followed by transient improvement and subsequent deterioration in the second week, this being especially conspicuous in patients who developed vasospasm; deterioration, at any rate, was distributed widely regardless of the initial CBF readings or magnitude of bleeding. Patients developing later neurological deficit (23% of the total) were those who showed a statistically significant increase of hemispheric asymmetries and regional hypoperfusion at the time when deterioration occurred. Accordingly, the Author calls attention to the practical value of CBF measurements in SAH patients, in view of the relationships that obtain between certain CBF patterns and the emergence of late neurologic deficits.

Acute Disease↗
PubMed1993

[Effect of hydralazine on the blood flow of normal and tumor tissues in hyperthermia].

We examined changes in blood flow in normal muscle and SCC-VII tumors of C 3 H/He mice following hyperthermia (HT) combined with the vasodilator hydralazine (Hyd) and compared them with similar changes after Hyd treatment or HT alone. Blood flow was measured by the Laser Doppler method, and oxygen tension was evaluated by polarography. The mean blood flow for the tumors in the Hyd group decreased. After HT treatment, it decreased to a low level. The largest decrease in tumor blood flow was observed after HT combined with Hyd administration. In normal muscle, no decrease in blood flow was induced by HT, Hyd or their combination. The magnitude of action of Hyd on the heat-induced changes in tumor blood flow and on damage to tumor vessels is considered to depend on the initial perfusion level. Therefore, we tried to clarify how this parameter was correlated with Hyd and/or HT-induced changes. In the HT and combined groups, the higher the temperature, the more significant the decrease in blood flow. In conclusion, these results suggest that the decrease in blood flow inside the tumor caused by Hyd plays an important role in enhancement of the hyperthermic anti-tumor effect.

Animals↗
PubMed1993

Nasal blood flow.

Although the assessment of allergic reactions was subjective for many years, it is now possible to evaluate nasal blockage objectively by measuring nasal airway resistance. To explore the pathophysiology of nasal blockage, however, it is necessary to analyze the separate components of obstruction, including secretions, cellular infiltrates, and microcirculatory parameters. The preferred techniques for measuring nasal mucosal blood flow are laser-Doppler velocimetry and radioactive xenon washout. Laser-Doppler velocimetry allows the measurement not only of blood flow but also of blood volume, red blood cell speed, and pulsatility of flow. It also permits continuous measurement of microcirculatory parameters over time. This technique has been used to assess the nasal microvascular response to neurohormones, antigenic challenge, and histamine challenge with and without antihistamine pretreatment.

Humans↗
PubMed1993

Variability of different patterns of skin oscillatory flux in healthy controls and patients with peripheral arterial occlusive disease.

Variability of patterns of laser Doppler flux motion was analysed at 5 different sites at the foot of 12 healthy controls and 24 patients with different degrees of ischemia due to peripheral arterial occlusive disease. Patterns were evaluated by means of the frequency histogram method. Three main flux motion components were detected at mean frequencies of 3.5 +/- 1.1 min-1 (low frequency waves, LF), 17.2 +/- 2.7 min-1 (high frequency waves, HF) and at 62.6 +/- 8.5 min-1 (pulsatile waves, PF). The characteristic pattern in normals consisted of LF and PF waves. In severe ischemia oscillatory flux was predominantly characterized by the combination of LF and HF waves and loss of pulsatile flux, or by the absence of any flux motion. Claudicants covered the entire spectrum of the flux motion patterns. In controls spatial variations were mainly due to the occasional presence of HF waves at one of the 5 sites. With increasing ischemia spatial variability of HF waves decreased due to more homogeneous presence. Loss of pulsatile flux was inhomogeneous in claudicants but almost complete in severe ischemia. Whereas LF waves were almost always observed at all sites of controls and claudicants there was considerable spatial variability in severe ischemia due to inhomogeneous loss of LF waves. Prevalence of the distinct flux motion patterns was well reproducible in controls and patients. Patterns showed a marked day to day variability when sites of measurement were compared.

Adult↗
PubMed1993

Betahistine-induced vascular effects in the rat cochlea.

Betahistine (BH) has been used widely to treat cochlear disorders, such as tinnitus and Meniere's disease. The mechanism of action of BH in the cochlea is assumed to be based on its histamine-like effect on H1 receptors in the cochlear vasculature, leading to an increased cochlear blood flow (CBF). Recently it has been shown that BH can strongly affect H3 heteroreceptors (a novel histamine receptor subclass) in the periphery, via an autonomic ligand. This mechanism may also contribute to the BH effects on CBF. This study was to validate BH effects in the cochlear vasculature and to investigate the possible mechanisms of action of this drug in the inner ear vasculature. We assessed the effects of BH on CBF with the laser Doppler flowmeter in 23 rats and concluded that BH affects vascular conductivity in the cochlea in a dose-dependent fashion; betahistine diffuses through the round window, but does not have access to vascular receptors or ligands once in the labyrinthine fluids; and the H1 receptors mediate the systemic and peripheral vascular effects of BH, whereas the cochlear effect involves cholinergic receptors.

Animals↗
PubMed1993

Retinal hemodynamics in proliferative diabetic retinopathy. A laser Doppler velocimetry study.

PURPOSE: This study investigated retinal hemodynamic changes associated with different pathologic features observed on fundus color and fluorescein angiography in patients with proliferative diabetic retinopathy. METHODS: Retinal circulatory characteristics were investigated in 25 eyes of 23 diabetic patients with proliferative retinopathy using a combination of bidirectional laser Doppler velocimetry and monochromatic fundus photography. RESULTS: Eyes with severe capillary nonperfusion had 32% less average volumetric blood flow rate (Q) than eyes with less severe nonperfusion (P = 0.0005). In addition, eyes with severe vessel staining with fluorescein had 20% less average Q than eyes without staining (P = 0.0508). Eyes with severe fluorescein leakage in the macula had a 17% larger total venous cross-section than eyes with milder leakage (P = 0.027). Eyes with clinically significant macular edema had 11% larger average venous diameter than eyes without this feature (P = 0.0085). CONCLUSIONS: Severe capillary nonperfusion and vessel staining with fluorescein are associated with decreased retinal blood flow rates. Vasodilatation may be an important factor for increased vascular permeability and macular edema in proliferative diabetic retinopathy.

Adult↗
PubMed1993

Laserflowgraphy: a new visual blood flow meter utilizing a dynamic laser speckle effect.

We developed a visual laser blood flow meter that is capable of providing two-dimensional color graphic representations of blood flow distribution for a given area by utilizing a dynamic laser speckle effect. The device is called the laserflowgraph. The principle and configuration of this flowmeter, comparison with the 133Xe clearance method, difference from thermography, and clinical uses of this flowmeter in flap monitoring are presented. Flow level of the laserflowgraph was significantly correlated with blood flow rate determined by 133Xe clearance in observations on the forearms of normal volunteers. The laserflowgraph reflected blood flow through the region between the skin surface and the deeper region of the papillary layer of the dermis. The laserflowgraph is a highly useful, practical, and reliable tool for assessing cutaneous blood flow and is expected to be applicable to various clinical fields.

Adult↗
PubMed1993

[The effect of prostaglandin E1 and prostaglandin F2 alpha in the ischemic small intestine of dogs].

The effect of PGE1 and PGF2 alpha in the ischemic intestinal tract were examined. In 40 mongrel dogs, we studied ischemic models of small intestine. PGE1 or PGF2 alpha was injected into the anterior mesenteric artery after reperfusion according to each occlusion time, and the tissue blood flow was measured on both mucosal and serous sides of small intestinal loop by laser flowmeter to examine the relation to the extent of tissue damage. Tissue blood flow of the ischemic intestine after the injection of PGE1 increased by 148-208% in the 3-5 hr occlusion group and by 86-110% in the 7-10 hr occlusion group. Tissue blood flow after the injection of PGF2 alpha decreased by 39-59% in the 3-5 hr occlusion group and by 1-15% in the 7-10 hr occlusion group. These results indicate that the effect of PGE1 and PGF2 alpha in the ischemic intestine would be available up to 3-5 hr of ischemia. Histological examination revealed that viability of the remaining crypt was high in the PGE1 injection group but low in the PGF2 alpha injection group. These findings suggest that PGE1, if try at the early stage, would be effective for the treatment of ischemic lesion.

Alprostadil↗
PubMed1993

Biological zero in laser Doppler measurements in normal, ischaemic and inflamed human skin.

The Biological Zero (BZ) signal in laser Doppler flowmetry was recorded during temporary occlusion of the arterial circulation to the limb by a blood pressure cuff inflated suprasystolically for 2 min. The non-thermoregulatory skin at the ankle was compared with the thermoregulatory skin over the toe pad in patients with lower limb arterial obstructive disease, elderly controls without arterial disease and young healthy adults under cool (15-17 degrees C) and warm (25-27 degrees C) ambient conditions. The absolute BZ values did not differ significantly within the three groups at the two room temperatures. However the resting laser Doppler flowmetry signal (LDflux) was consistently higher under warm than cold room temperatures: these differences were much greater at the toe than at the ankle. Accordingly, the relative size of BZ, expressed as a percentage of the resting LDflux, was least over the toe in a warm room (5-10%) and greatest over the malleolus (59-83%) in the cold room. The changes during the evolution of a positive tuberculin skin reaction were followed as a model of chronic inflammation in man. The resting LDflux rose 10 fold (from 0.3 to 3.4V) while the change in the BZ was minor (0.16-0.2V). Thus the rise in LDflux in a fully developed tuberculin reaction was approximately 30X greater than that for the corresponding BZ. Concurrent measurements of the alternative output from the laser Doppler flowmeter (CMBC) showed in a similar pattern. Since the BZ signal can be a substantial proportion of the resting LDflux measurement, we support the recommendation that the BZ should be measured wherever possible and practicable, for subtraction from the observed LDflux to assess the true flow: 'raw' LDflux measurements should be interpreted with extreme caution, particularly at relatively low resting LDflux levels.

Adolescent↗
PubMed1993

Evidence for skin microvascular compartmentalization by laser-Doppler and photoplethysmographic techniques.

Indices of perfusion were obtained using commercial laser-Doppler instruments with differing wavelengths on metatarsal skin of sheep (which is abundant with AVAs) and compared with quantitative measurements of AVA and capillary blood flow using microspheres; an infra-red photoplethysmograph was also compared. The data provide physiological evidence that laser-Doppler instruments of longer wavelength sense to a greater depth, and our photoplethysmograph behaves similarly to a "near-infra-red" laser. Thus, we suggest that near-infra-red light, either laser-Doppler or photoplethysmograph, should be used to measure a parameter most representative of total local blood flow, and light of a very much shorter wavelength, probably green light, would allow more confidence in estimates of true capillary perfusion. Because the commonly used visible red light can, but does not necessarily detect deep AVA perfusion, the influence depending upon the magnitude of the AVA perfusion, measurements by an instrument based on such red light is difficult to define.

Animals↗
PubMed1992

[Microcirculatory changes in mitral prolapse as an expression of a systemic change in the connective tissue].

Many authors hypothesize that mitral valve prolapse (MVP) can be, in most cases, only a clinical sign of a primitive and systemic disorder of the connective tissue, like in Marfan Syndrome (MS). In our previous works we supported the presence of morphological and functional alterations of the microcirculation in patients affected by MS. In order to characterize a possible common denominator between these pathologies we have studied the cutaneous microcirculation in a group of patients affected by MVP, divided into 2 groups: anatomic MVP (MVP) and MVP syndrome (MVPS). The morphologic parameters have been investigated by nailfold capillaroscopy while digital laser-Doppler was used to study skin flowmetry. The results have been compared with a control group. Capillaroscopic remarkers showed an architecturally disorganized microvasculature with aspects related to a reduced compactness of the microvasculature unit with a significatively higher score compared with controls (7.3 +/- 2.9 vs 3.6 +/- 1 p less than 0.0005). Laser-Doppler flowmetry showed a significatively reduced rest flow; ischemic test showed: spike time 48.9 +/- 36.9 vs 15.3 +/- 7.7 s (p less than 0.0005), hyperemic acme 6.6 +/- 2.7 vs 12.5 +/- 8.4 UP (p less than 0.002); % increase 32.1 +/- 20.2 vs 51.5 +/- 15.4 (p less than 0.002). Thermic test showed a significatively higher thermic acme 8.7 +/- 4.2 vs 12.6 +/- 9.11 UP (p less than 0.05). These results appeared to be correlated with stage pathology as it was observed a severe microvasculature disorders in MVPS. Therefore we suppose that a phenotypic continuum may exist between MS and MVP.

Adult↗
PubMed1994

Effects of neural blockade and general anesthesia on the laser-Doppler skin blood flow waves recorded from the finger or toe.

Effects of neural blockade and general anesthesia on the basic wave (BW) and the reflex wave (RW) among the laser-Doppler (L-D) skin blood flow waves recorded on the finger or toe were studied in 2 volunteers and 42 patients. The BW was continuous, rhythmic and independent of respiratory movements. The RW, which was induced by a deep inspiration or a snapping sound, was a transient marked reduction in blood flow. The BW was almost flattened and the RW was no longer induced at the finger under complete wrist block (n = 2), or under cervical or upper thoracic epidural anesthesia extended caudally over T7 (n = 2). On the other hand, the BW was still detected with reducing frequency and the RW could be provoked with one exception at the finger on the side with a sympathetic ganglion block at the C6 vertebral level (n = 14). The BW and RW at the toe were retained under lumbar subdural anesthesia (n = 6) as well. However, under the combination of lumbar subdural anesthesia and lower thoracic epidural anesthesia extending rostrally over T4 (n = 6), both the BW and the RW disappeared at the toe. In the course of deepening nitrous oxide/enflurane anesthesia (n = 10), the BW gradually reduced in frequency until it was almost flattened, and it became difficult to provoke the RW. L-D flowmetry of the finger or toe could be a useful clinical measure for detecting the presence or absence of sympathetic function controlling cutaneous vasomotion.

Adult↗
PubMed1982

Current status of noninvasive tests in the diagnosis of peripheral arterial disease.

In this review of the current status of the vascular laboratory, the major emphasis has been upon those tests that have become well-established and documented, including resting pressure, pulse volume measurements, velocity studies, and three stress measurements--exercise ankle pressure, postocclusive reactive hyperemia, and the toe pulse reappearance time. Additional technology that may have application to peripheral arterial disease includes photoplethysmography, transcutaneous oxygen tension, laser-Doppler velocimetry, fluorescein angiography, infrared thermography, and transcutaneous electromagnetic flowmetry. These techniques, which are currently in development and experimental trial, were not discussed but are likely to provide significant additional information. The future role of the vascular diagnostic laboratory in the area of peripheral arterial occlusive disease appears clear. It has already become a standard resource of the community hospital and tertiary referral center. Its functions will become more and more generally accepted with time as newly graduating physicians who have been exposed to this technology enter the practice of medicine. It should permit obtaining an evaluation of all patients at the expert level, aid in the education of all physicians concerned with peripheral arterial disease, and play an important part in guaranteeing a higher level of patient care than has heretofore been available.

Arterial Occlusive Diseases↗
PubMed1988

Partitional measurement of capillary and arteriovenous anastomotic blood flow in the human finger by laser-Doppler-flowmeter.

This study was made to see whether changes in blood flow through the capillaries and arteriovenous anastomoses (AVA's) of the human finger can be measured by noninvasive flowmetry. Total finger blood flow (FBF) was measured by venous occlusion plethysmography; blood flow was measured by a laser-Doppler flowmeter (ADVANCE, ALF-2100, Tokyo, Japan) using probes with optic fiber separations of 0.3 mm (LDF-0.3) and 0.7 mm (LDF-0.7). The maximum sensitivities for LDF-0.3 and LDF-0.7 were at depths of 0.8 and 1.2 mm from the tissue surface respectively. Two series of experiments were performed on separate days. In the first series the test hand was immersed in a water bath whose temperature (Tw) was 25 degrees C at an ambient temperature (Ta) of 25 degrees C. Tw was raised to 35 degrees C (local hand warming), which was then followed by an increase in Ta to 35 degrees C (whole body warming). FBF, LDF-0.3, and LDF-0.7 increased during these thermal stimulations. However, the relationship of FBF to LDF-0.3 showed two different regression lines. In contrast, the relationship of FBF to LDF-0.7 showed a single regression line. In the second series, with Ta at 35 degrees C, the test hand was immersed in a water bath at Tw 35 degrees C. Tw was then raised every 10 min by 2 degrees C steps from 35 to 41 degrees C. At Tw 39-41 degrees C, FBF and LDF-0.7 in the test hand were significantly decreased compared with those at Tw 35 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗