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Results for “Laser-Doppler Flowmetry”

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At least 685 records · Page 38Linked to original sources
PubMed1994

[Respiration-dependence of cutaneous laser Doppler flow motion].

The aim of this study was to show and to quantify the breath-dependency of cutaneous fluxmotion in the volar proximal forearm using a new computer-aided system. A meanflux-related index (MI) representing the intensity of the influence of respiration on fluxmotion was calculated. There was a good correlation between MI and the rate of respiration under spontaneous breathing: the lower the rate of respiration, the higher the value of MI. Prescribing a constant breathing rhythm amplifies this frequency-dependent effect. According to occurrence of low rates of respiration (< 12/min) also under physiological conditions the respiration should be simultaneously recorded while assessing fluxmotion.

Adolescent↗
PubMed1994

Toe systolic blood pressure after local cooling in primary Raynaud's phenomenon.

First toe systolic blood pressures (FTSBP) before and after first toe cooling were measured with the laser Doppler method in 17 normal women and 10 female patients with primary Raynaud's phenomenon (PRP). The room temperature was maintained at 26 degrees C. There was no significant difference in toe-arm systolic blood pressure ratio between the two groups. After toe cooling at 10 degrees C, the PRP group had a significantly greater reduction in FTSBP than the normal group. Measurement of FTSBP before and after toe cooling is a useful method for assessing Raynaud's phenomenon in the toes of patients with PRP.

Adult↗
PubMed1994

Influence of biological response modifiers: measurement of tumor blood flow and temperature.

Human recombinant interferon-alpha-2b (IFN) is known to inhibit growth of both normal and tumor cells and to stimulate immune effector cell function. We have previously shown that IFN and other biological response modifiers augment accumulation of radiolabeled antibodies in tumors. This investigation demonstrates that 30 min post i.m. administration of IFN significantly (p < 0.01) enhances tumor perfusion in tumor-bearing mice and persists for a much longer time than in normal tissue, which, in part, may contribute to the enhanced tumor uptake of radiolabeled monoclonal antibodies within 1.5 h of their administration. Histological examinations of tumors obtained from animals receiving IFN 72 h previously did not show changes in inflammatory cells. Our investigation shows that laser Doppler flowmetry and color Doppler imaging can provide an excellent means of measuring tumor perfusion changes in small living animals where radioactive tracers cannot be used.

Animals↗
PubMed1994

[Compression stockings in treatment of lower leg venous ulcer].

AIM: of the study was to evaluate the efficiency of medical compression stockings, which do not require special application techniques, compared with short stretch bandages for treating leg-ulcers. STUDY-DESIGN AND PATIENTS: Prospective trial on a total of 50 out-patients with leg-ulcers randomly allocated into two therapy-groups: 25 patients got firm compression bandages using short stretch material (Rosidal K), 25 patients were treated by medical compression stockings (Thrombo+Sigvaris 503). Due to the statistically significantly lower mean age and longer duration of the ulcers in the Sigvaris-group only restricted comparison of the treatment groups is possible. Local dressings in both groups consisted of a nonadherent, absorbing material (Vliwin) with an individually modelled rubber foam pad on top. The end-point was complete ulcer-healing, in a period of 3 months. METHODS: The following parameters were measured: area of ulceration, compression-pressure, tcPO2 and Laser-Doppler-Fluxmetry at the ulcer border before and after 3 minutes of arterial occlusion, venous volume and venous filling index by air plethysmography (APG) with and without compression. RESULTS: After 3 months 21 cases (84%) were healed in the Sigvaris-group and 13 (52)% in the Rosidal-group. This significant difference may be partly explained by the more favorable starting condition of the stocking-patients. However, one major advantage of stockings over short stretch bandages is the maintenance of an adequate pressure if they are not renewed for several days. CONCLUSION: Therapy of venous ulcers by medical compression stockings may be an effective approach for fit and cooperative patients.

Adult↗
PubMed1993

Differentiation of platelets from red cell fragments using laser technology: comparison between splenectomized and nonsplenectomized thalassemic patients.

Platelets from 59 beta-thalassemia/hemoglobin E (beta-thal/HbE) patients (19 were splenectomized) and 97 normal individuals were studied using laser and computer analysis. Fragmented red cells of similar platelet volume were differentiated from platelets using laser inspection of the intracellular hemoglobin of the fragmented red cell. The patients had increased platelet count than normal cases at p < 0.0001 (nonsplenectomized, mean +/- SE = 32.4 +/- 21.9; splenectomized, 617.5 +/- 64.2; normal, 264.7 +/- 6.4 x 10(3) cells/dl). Splenectomized patients had greater platelet counts than nonsplenectomized cases (p < 0.0001). Numbers of small red cells, probably red cell fragments, markedly increased in nonsplenectomized patients. Increased heterogeneity in platelet size was demonstrated in the patients of both groups. The nonsplenectomized patients had significantly higher mean platelet volume than normal (p < 0.02) and splenectomized cases (p < 0.01). Increased platelet number and heterogeneity in platelet population may involve in pulmonary thrombosis in splenectomized patients.

Adolescent↗
PubMed1994

Intraplaque hemorrhage of the carotid arteries: diagnosis by duplex scanning.

Eighty-three patients with intraplaque hemorrhage of the carotid arteries, explored by Duplex scanning, are reported; 36 among them were also studied by digital angiography and 28 were operated on. The echographic aspect suggesting the presence of an intraplaque hemorrhage is that of a hypo-anechogenic stria separating the intimal plaque from the media-adventitia complex. On the contrary, the angiographic findings are aspecific and unrelated to the presence of intramural blood clots. We think that duplex scanning is the investigation of choice in detecting intraplaque hemorrhage of the carotid arteries. The role of other radiological techniques, such as computed tomography of the neck and magnetic resonance, is also discussed.

Aged↗
PubMed1994

Changes in muscle and liver lactate concentrations after endotoxin infusion in rats.

The interstitial lactate concentration in rat skeletal muscle and liver was measured using a microdialysis method during the early stage of endotoxemia and during lactic acid infusion. The lactate concentration in the muscle and liver interstitium never exceeded the blood lactate concentration throughout the 180 min period after endotoxin administration. The present findings also showed that the muscle and liver interstitial lactate concentration gradually increased in endotoxin-infused animals compared to that in lactic-acid infused animals, although the blood lactate concentration in lactic acid-infused animals was the same as that in endotoxin-infused animals. These findings suggest that the skeletal muscle and liver may consume lactate in an endotoxemic condition. However, the capacity of lactate consumption in the skeletal muscle might gradually decrease after endotoxin administration, although that in liver might be well preserved.

Animals↗
PubMed1995

[Changes in blood flow and skin reaction following radiation therapy].

Skin blood flow (SBF) during radiation therapy was measured and compared with skin reaction to examine the relationship between skin reaction and blood flow. The SBF of 50 patients including 16 with head and neck (H&N) cancer, 13 with breast cancer and eight with lung cancer were analyzed. In the H&N patients, SBF was increased according to the treated dose, while in the breast cancer patients SBF was slightly increased at 10 Gy, and did not change up to 40 Gy. In the lung cancer patients SBF was not increased until 20 Gy, and thereafter increased moderately at 30 Gy. Among H&N, breast and lung cancer patients, the most severe skin reaction was observed at the earliest time in breast cancer patients, while blood flow was only slightly increased. This must have resulted in a relatively higher skin dose than the reference point dose in breast cancer patients. Therefore, differences in the relationship between SBF and skin reaction were observed among different types of cancer patients. However, in H&N cancer patients, SBF was increased as skin dose increased. Skin blood flow could be a good indicator by which to estimate skin reaction quantitatively when the daily skin dose is around 1.6 Gy.

Aged↗
PubMed1994

Ischaemia of the small intestine in patients with systemic sclerosis: Raynaud's phenomenon or chronic vasculopathy?

We investigated duodenal and gastric mucosal blood flow by endoscopic laser Doppler flowmetry (LDF) in ten patients with systemic sclerosis (SSc) and in ten healthy volunteers. In addition, we tested for the presence of small bowel bacterial overgrowth by jejunal aspiration. Jejunal aspiration and LDF were done consecutively, via a gastroscope, using a flexible catheter and laser Doppler probe. Following these procedures, two duodenal biopsies were obtained for light and electron microscopy. Mean duodenal and gastric blood flow were significantly lower in patients with SSc than in normal subjects (516 flux units vs. 240, 521 vs. 202, both p < 0.001). There was no correlation between age and blood flow in patients or volunteers. Four of the ten patients had evidence of significant bacterial overgrowth on jejunal aspiration (> 10(5) colony-forming units/ml). These findings support the hypothesis that within the small intestine of patients with SSc, factors independent of bacterial overgrowth may be responsible for malabsorption. The observed reduction in small-intestine mucosal blood flow may play an important contributory role. Further studies are required to determine whether this represents reversible or chronic progressive ischaemia, and its effect on nutrient absorption.

Adult↗
PubMed1994

[Effect of pirenzepine on gastric mucosal blood flow in patients after cardiac surgery].

Effect of pirenzepine on gastric mucosal blood flow (GMBF) in adult patients after coronary artery bypass grafting and mitral and aortic valve replacement was evaluated by using endoscopic laser-Doppler velocimetry. Heart rate, blood pressure and cardiac output increased temporarily after intravenous administration of pirenzepine 20 mg. GMBF also increased with these hemodynamic changes. However, GMBF remained significantly higher even after the decrease of cardiac output. Therefore, the increase in GMBF, which might be due in part to increase in cardiac output, could be explained by pirenzepine's own effect on gastric mucosa. Since the GMBF is one of the most important gastric mucosal defensive factors, pirenzepine may be useful in preventing acute gastric mucosal lesions in patients with low cardiac output.

Aged↗
PubMed1994

[Physiological diagnostic techniques of patients with vasculitis].

This article discusses physiological diagnostic methods in the intractable vasculitis, including Buerger's, Takayasu's and vasculo-Behçet disease. Clinical manifestations of these diseases depend on the lesions of the diseased arteries or veins such as obstruction of the extremities often occurring in Buerger's disease, the obstruction of aortic arch branches in Takayasu's disease and the deep vein thrombosis in vasculo-Behçet disease. Measurements of segmental blood pressure and flow allows a detection of peripheral vascular disease and non-invasive diagnostic techniques, such as the doppler ultrasonic techniques and strain-gauze plethysmography, permit accurate evaluation of arterial occlusive disease and estimation of its physiological significance. Noninvasive diagnostic techniques, together with clinical symptoms and physical examinations, make possible correct diagnosis and subsequently appropriate treatment.

Blood Pressure Determination↗
PubMed1994

[NPT: nocturnal penile tumescence test].

The recording of the variations of penile tumescence and rigidity during nocturnal unconscious erections that usually occur with the REM phases of sleep, has been considered the diagnostic tool of choice in the workup of erectile disturbances for a number of years. Such a success is partly due to its absence of invasiveness. Moreover this test was believed to allow to differentiate between the psychogenic and organic origin of impotence. As some authors have recently reported, anxiety state (common among patients who undergo invasive andrological procedure in the office) can at times influence the content of the dream state, thus negatively affecting the spontaneous nocturnal erections. Besides, sleep disturbances such as apnea and motor agitation can also induce erroneous interpretations of NPT graphs. Further, dysfunctions at the level of the cortex and the spine still allow the occurrence of nocturnal tumescence but determine an erectile deficit in the awake state. Clinically, all this poses new questions about the effectiveness of the NPT test in the study of the origin of impotence. The diagnostic methods, despite its world-wide diffusion, remains, under certain aspects, obscure: the operative details and, above all, its interpretative criteria. All this impedes the achievement of uniformity in the evaluation of the results obtained thanks to this test (e.g. the number and duration of erectile episodes, the interpretation of tumescence on its own, of the basal-apical dissociation, of the erectile episodes occurring immediately before waking, and of those of short duration).

Aged↗
PubMed1994

[Doppler velocimetry].

After a brief historical introduction, the Authors describe the methodology of the continuous wave basic and dynamic Doppler examination of the penile arteries as well as the main normal and pathologic patterns. Some special tensiometric tests are reported. Advantages and limits of the afore mentioned examinations are discussed.

Humans↗
PubMed1994

[Tissue blood flow of the sigmoid colon for safe anastomosis following ligation of the inferior mesenteric artery].

We examined the tissue blood flow (TBF) of the sigmoid colon to determine which level of inferior mesenteric artery. In 13 patients, TBF of the sigmoid colon was measured in the control state and the clamped state, in which the inferior mesenteric artery (IMA), left colic artery and the rectal were wall clamped. In the clamped state, means of TBF at 10 cm and 15 cm distal to the descend-sigmoid junction were 1.87 +/- 0.77 and 1.10 +/- 0.40, respectively. Mean of TBF at 15 cm was significantly lower than that at 10 cm. In conclusion, TBF which is enough for safe anastomosis reaches as far as 10 cm distal from the descend-sigmoid junction after ligation of IMA. Anastomosis at this level in anterior resection of the rectum is safe in concerning with TBF.

Adult↗
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↗