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Twenty three patients aged from 41 to 75, which have had ischemic stroke in the carotid basin (up to 2 years after an acute period of the stroke), have been examined. The course of magneto-laser therapy lasted 15 days. The author carried out neurological examinations, determined the state of psychoemotional activity, cerebral hemodynamics and frequency-amplitude indices of the brain to assess the mechanisms of MLT effect on the CNS functional state in patients being in a rehabilitative period after ischemic stroke. The course of MLT administration improves cerebral hemodynamics, increases the level of the bioelectrical activity of the brain. We can recommend based on obtained results MLT in the system of rehabilitation of patients which had had ischemic stroke.

We present a method to produce vascular disruptions within rat brain parenchyma that targets single microvessels. We used two-photon microscopy to image vascular architecture, to select a vessel for injury and to measure blood-flow dynamics. We irradiated the vessel with high-fluence, ultrashort laser pulses and achieved three forms of vascular insult. (i) Vessel rupture was induced at the highest optical energies; this provides a model for hemorrhage. (ii) Extravasation of blood components was induced near the lowest energies and was accompanied by maintained flow in the target vessel. (iii) An intravascular clot evolved when an extravasated vessel was further irradiated. Such clots dramatically impaired blood flow in downstream vessels, in which speeds dropped to as low as approximately 10% of baseline values. This demonstrates that a single blockage to a microvessel can lead to local cortical ischemia. Lastly, we show that hemodilution leads to a restoration of flow in secondary downstream vessels.

This study was designed to investigate the dose-rate dependent effects of ionising radiation on endothelium- and NO-mediated reactivity of aorta and coronary vessels. Rats were exposed to acute ((137)Cs, 9 x 10(-4) Gy s(-1), 18 min) and chronic ((137)Cs, 2.8 x 10(-7) Gy s(-1), 41 days) radiation in 1 Gy dose. Acute irradiation transiently increased coronary flow in eNOS-activity-dependent manner on day 3 after exposure. In striking contrast, chronic irradiation caused a significant depression of coronary flow even on day 90 after irradiation and abolished the effects of NO-synthase inhibitor N-nitro-L-arginine methyl ester (10 micromol l(-1)). Furthermore, low intensity radiation strongly diminished the vasodilator properties of NO-donor sodium nitroprusside (5 micromol l(-1)). A similar pattern was observed in aortic rings. Endothelium-dependent vasodilation was increased on days 3 and 10 after acute irradiation, but strongly inhibited following chronic exposure for the entire post-radiation period. This was accompanied by a diminished vasodilator response to NO-donor on days 3, 10 and 30 of post-radiation but not on day 90. The data suggest that ionising radiation in 1 Gy induces changes of aortic and coronary vessels reactivity depending on the dose-rate and the interval after exposure.

A two-dimensional model was developed to model the effects of dynamic changes in the physical properties on tissue temperature and damage to simulate laser-induced interstitial thermotherapy (LITT) treatment procedures with temperature monitoring. A modified Monte Carlo method was used to simulate photon transport in the tissue in the non-uniform optical property field with the finite volume method used to solve the Pennes bioheat equation to calculate the temperature distribution and the Arrhenius equation used to predict the thermal damage extent. The laser light transport and the heat transfer as well as the damage accumulation were calculated iteratively at each time step. The influences of different laser sources, different applicator sizes, and different irradiation modes on the final damage volume were analyzed to optimize the LITT treatment. The numerical results showed that damage volume was the smallest for the 1,064-nm laser, with much larger, similar damage volumes for the 980- and 850-nm lasers at normal blood perfusion rates. The damage volume was the largest for the 1,064-nm laser with significantly smaller, similar damage volumes for the 980- and 850-nm lasers with temporally interrupted blood perfusion. The numerical results also showed that the variations in applicator sizes, laser powers, heating durations and temperature monitoring ranges significantly affected the shapes and sizes of the thermal damage zones. The shapes and sizes of the thermal damage zones can be optimized by selecting different applicator sizes, laser powers, heating duration times, temperature monitoring ranges, etc.

The objective of the present study was to reveal an interaction between choroidal blood flow (ChBF) and light-induced photoreceptor activity, a physiological coupling that has been already demonstrated for retinal blood flow but rejected for ChBF. Ten healthy adults volunteered for this study. A real-time recording near-infrared laser-Doppler flowmeter was used to quantify the subfoveal ChBF while the luminance of blue flicker between 1 and 64 Hz was first increased and then decreased by 4.0 log units in 1.0-log unit steps between 0.0375 and 375 cd/m2. In separate testing, flash electroretinograms (ERGs) provided electrophysiological indexes of the relative response of short-wave cones (s-cones) and rods to blue light stimulation. Group-averaged, normalized ChBF measurements revealed that it was modulated by approximately 9% by flicker frequency. Increasing the blue flicker luminance from low to high attenuated the subfoveal ChBF, volume, and velocity by approximately 32%, approximately 30%, and approximately 5%, respectively. Decreasing the luminance from high to low over the same range had no effect on the subfoveal choroidal hemodynamics. The markedly different effects of reversed directions of change in blue flicker luminance on the subfoveal ChBF were linked to transitions between rod-dominated and s-cone-dominated retinal responses. Collectively, these findings indicate that the blue light-induced photoreceptor response is associated with a differential distribution of the ChBF across the ocular fundus according to the degree and type of retinal photoreceptor stimulated.

Although no effects of permanent magnets on resting skin blood flow (SBF) in humans have yet been demonstrated, the possibility that magnet related effects might modify dynamic SBF changes has not been previously studied. We hypothesized that magnets may alter local neurovascular mechanisms to cause changes in normal SBF vasoactive responses. To test this, we studied the effects of a magnet on SBF reductions induced by sympathetic reflexes associated with deep inspirations. SBF was continuously monitored by a dual channel laser-Doppler flowmeter with probes on the middle finger dorsum of both hands of 24 healthy subjects. In the first of two successive intervals, each of the fingers rested on sham ceramic magnets (control interval). Subsequently, one finger rested on an active magnet and the other finger on a sham (experimental interval). Skin temperatures were also measured. The magnet was a 37 mm diameter x 14 mm thick ceramic magnet with a surface field strength of 85 mT measured in the geometrical center of the magnet. Field strength at the finger dorsum, 13 mm above magnet, was 31.5 mT. During each interval, three deep breaths were used to elicit SBF reductions. Responses were calculated as the percent reduction in SBF from its prior 20 s average. Breaths in each interval were spaced 3 min apart to permit full recovery between responses. The experimental interval started after an active magnet was in place for 20 min. Results showed no significant difference in either vasoconstrictive responses or skin temperature due to the magnet. We conclude that magnets of the type, strength and duration used, have no significant effect on vasoconstrictive processes associated with this sympathetic reflex in this group of healthy subjects., (Copyright 2005 Wiley-Liss, Inc.)

Clinical magnetic resonance imaging (MRI) was introduced in the early 1980s and has become a widely accepted and heavily utilized medical technology. This technique requires that the patients being studied be exposed to an intense magnetic field of a strength not previously encountered on a wide scale by humans. Nonetheless, the technique has proved to be very safe and the vast majority of the scans have been performed without any evidence of injury to the patient. In this article the history of proposed interactions of magnetic fields with human tissues is briefly reviewed and the predictions of electromagnetic theory on the nature and strength of these interactions are described. The physical basis of the relative weakness of these interactions is attributed to the very low magnetic susceptibility of human tissues and the lack of any substantial amount of ferromagnetic material normally occurring in these tissues. The presence of ferromagnetic foreign bodies within patients, or in the vicinity of the scanner, represents a very great hazard that must be scrupulously avoided. As technology and experience advance, ever stronger magnetic field strengths are being brought into service to improve the capabilities of this imaging technology and the benefits to patients. It is imperative that vigilance be maintained as these higher field strengths are introduced into clinical practice to assure that the high degree of patient safety that has been associated with MRI is maintained.

Various experimental studies carried out over the last 30-40 years have examined the effects of the chronic or acute exposure of laboratory animals to static magnetic fields. Many of the earlier studies have been adequately reviewed elsewhere; few adverse effects were identified. This review focuses on studies carried out more recently, mostly those using vertebrates, particularly mammals. Four main areas of investigation have been covered, viz., nervous system and behavioural studies, cardiovascular system responses, reproduction and development, and genotoxicity and cancer. Work on the role of the natural geomagnetic field in animal orientation and migration has been omitted. Generally, the acute responses found during exposure to static fields above about 4 T are consistent with those found in volunteer studies, namely the induction of flow potentials around the heart and the development of aversive/avoidance behaviour resulting from body movement in such fields. No consistently demonstrable effects of exposure to fields of approximately 1T and above have been seen on other behavioural or cardiovascular endpoints. In addition, no adverse effects of such fields on reproduction and development or on the growth and development of tumours have been firmly established. Overall, however, far too few animal studies have been carried out to reach any firm conclusions.

Electromagnetic hypersensitivity (EH) is an increasing problem in modern industrial societies. As crawling sensations are frequently mentioned by EH patients alterations in cutaneous microcirculation possibly linked to exposure to magnetic fields might be involved in the development of such sensations and further dysesthesias. In seven healthy volunteers and in three persons convinced to suffer from EH the microcirculation of the right thumb was determined by laser-Doppler-flowmetry (LDF) during exposure to circularly polarized 50 Hz magnetic flux densities of 96 mT. During field exposure the LDF values remained constant. The LDF ratio "field on/field off" was found to be 1.03 +/- 0.03. In contrast, reactive hyperemia and hyperventilation caused significant changes in the LDF values of volunteers as well as of EH patients. Following arterial congestion of the forearm microcirculation of the thumb was clearly increased during reperfusion, and the LDF values were elevated up to 2.02 +/- 0.36. 10 deep breaths caused a significant decrease in the LDF values up to 0.63 +/- 0.18. In conclusion, reactive hyperemia and hyperventilation caused clear alterations of cutaneous microcirculation, whereas, 50 Hz magnetic fields had no influence on cutaneous microcirculation.

Purpose: Wet-type age-related macular degeneration is a refractory eye disease that involves choroidal neovascularization. Randomized controlled trials of low-dose radiotherapy for this disease performed in Japan showed that, at 12 months of follow-up, visual acuity was significantly well preserved and the neovascular membrane size decreased. Because understanding the effect of irradiation on new vascular networks is an important prerequisite for clinical trials, we used a rat skinfold chamber technique to investigate X-ray-induced changes in neovasculature microcirculation., Methods and Materials: Neovascularization was induced in rat skinfold chambers via polyvinyl chloride resin plates. Neovessels were irradiated in a single 10-Gy dose, after which, changes in vascular density, blood velocity, tissue blood flow, and interstitial fluid pressure (IFP), were measured., Results: Vascular density, tissue blood flow, and IFP measurements in resin-induced inflammatory tissue were much higher than those measurements in normal tissue. Although overall blood velocity was low and sluggish or blood-flow stasis occurred in the neovascular network, after a single 10-Gy dose of radiation, the velocity increased, stasis improved markedly, and many dilated vessels narrowed. Thereafter, vascular density, blood flow, and IFP significantly decreased and approached normal values., Conclusion: These findings may help explain clinical results related to radiotherapy-induced changes in neovascular membranes in age-related macular degeneration. Both vascular morphology and vascular function in inflammatory tissue returned to normal, without vessel destruction, after an appropriate radiation dose.

Aims: The electrical point stimulation system (P-STIM) reflects a new, miniaturized system for pain therapy through ear acupuncture. For this reason, ultrathin needles were applied at the ear. The needles stimulate the acupuncture areas at the ear using electrical impulses, which come from a little generator applied behind the acupunctured ear., Methods: This study describes continuous, non-invasive measurements of near infrared spectroscopy (NIRS) and multidirectional transcranial Doppler sonography in two healthy females (aged 23 and 27 years) during stimulation with P-STIM, for the first time., Results: The results of the pilot measurements have shown that electrical point stimulation using the new electrical stimulation system on eye acupuncture points is able to modulate the mean blood flow velocity (vm) of the supratrochlear artery. These effects were present using a stimulation frequency of 100 Hz. A lower increase in vm was found in the middle cerebral artery. In addition, stimulus induced, quantifiable and reproducible alterations of the regional cerebral NIRS parameters were be detected., Conclusion: For the first time, P-Stim allows intermittent ear acupuncture stimulation for up to several days in combination with complete mobility for the patient.

Functional hyperemia requires the coordination of smooth muscle cell relaxation along and between branches of the arteriolar network. Vasodilation is conducted from cell to cell along the arteriolar wall through gap junction channels composed of connexin protein subunits. Within skeletal muscle, it is unclear whether arteriolar endothelium, smooth muscle, or both cell layers provide the cellular pathway for conduction. Furthermore, the constitutive profile of connexin expression within the microcirculation is unknown. We tested the hypothesis that conducted vasodilation and connexin expression are intrinsic to the endothelium of arterioles (17 +/- 1 microm diameter) that supply the skeletal muscle fibers in the cremaster of anesthetized C57BL/6 mice. ACh delivered to an arteriole (500 ms, 1-microA pulse; 1-microm micropipette) produced local dilation of 17 +/- 1 microm; conducted vasodilation observed 1 mm upstream was 9 +/- 1 microm (n = 5). After light-dye treatment to selectively disrupt endothelium (250-microm segment centered 500 microm upstream, confirmed by loss of local response to ACh while constriction to phenylephrine and dilation to sodium nitroprusside remained intact), we found that conducted vasodilation was nearly abolished (2 +/- 1 microm; P < 0.05). Whole-mount immunohistochemistry for connexins revealed punctate labeling at borders of arteriolar endothelial cells, with connexin40 and connexin37 in all branches and connexin43 only in the largest branches. Immunoreactivity for connexins was not apparent in smooth muscle or in capillary or venular endothelium, despite robust immunolabeling for alpha-actin and platelet endothelial cell adhesion molecule-1, respectively. We conclude that vasodilation is conducted along the endothelium of mouse skeletal muscle arterioles and that connexin40 and connexin37 are the primary connexins forming gap junction channels between arteriolar endothelial cells.

Because the regulation of microcirculation in the cerebral cortex cannot be analyzed without measuring the blood flow dynamics and oxygen concentration in cerebral microvessels, we developed a fluorescence and phosphorescence system for estimating red blood cell velocity and oxygen tension in cerebral microcirculation noninvasively and continuously with high spatial resolution. Using red blood cells labeled with fluorescent isothiocyanate to visualize red cell distribution and using the oxygen quenching of Pd-meso-tetra-(4-carboxyphenyl)-porphyrin phosphorescence to measure oxygen tension enabled simultaneous measurement of blood velocity and oxygen tension. We examined how the measurement accuracy was affected by the spatial resolution and by the excitation laser light passing through the targeted microvessel and exciting the oxygen probe dye in the tissue beneath it. Focusing the excitation light into the microvessel stabilized the phosphorescence lifetime at each spatial resolution; moreover, it greatly reduced phosphorescence from the brain tissue. Animal experiments involving acute hemorrhagic shock demonstrated the feasibility of our system by showing that the changes in venular velocity and oxygen tension are synchronized to the change in mean arterial pressure. Our system measures the red cell velocity and oxygen concentration in the cerebral microcirculation by using the differences in luminescence and wavelength between fluorescence and phosphorescence, making it possible to easily acquire information about cerebral microcirculatory distribution and oxygen tension simultaneously.

Background: To clarify the effect of extremely low frequency electromagnetic field (ELF-EMF) on the microcirculatory system, acute effects on leukocyte-endothelium interactions resulting from ELF-EMF exposure were examined with conscious BALB/c mice by means of a dorsal skinfold chamber., Materials and Methods: The fluorescent dye, rhodamine 6G, was injected into the caudal vein to visualize leukocytes in vivo and to analyze leukocyte-endothelium interactions. Mice were exposed in vivo to 50 Hz linear sinusoidal wave EMF at magnetic flux densities of 3, 10 or 30 mT, for 30 minutes., Results: The mean velocity of free flowing leukocytes in the center stream of venules revealed no distinct changes following exposure. However, at a flux density of 30 mT, the number of adherent leukocytes, defined as the total number of rolling and endothelium-adhering leukocytes, increased significantly following ELF-EMF exposure (p<0.05); no significant differences in adherent cell numbers were found in the 3 mT and 10 mT exposure groups or sham controls comparing pre- and post-exposure periods., Conclusion: These results demonstrated that high magnetic flux densities of ELF-EMF had an effect on leukocyte-endothelium interactions and indicated that a threshold level for this phenomenon exists in the range of 10-30 mT under these experimental conditions.

We have previously reported species differences in the rate of skin heating in response to millimeter wavelength microwave exposure. We hypothesized that these differences were predominantly a function of species differences in the ability to increase skin blood flow during local heating. Mathematical modeling also suggested that, in humans, the rate of skin heating during prolonged millimeter wavelength exposure would be dependent on skin blood flow. In order to empirically test this hypothesis, we determined the role of baseline skin blood flow on the rate of cutaneous heating induced by 94-GHz microwave energy in humans (3 female, 3 male) using infrared thermography and laser Doppler imaging to measure skin temperature and relative skin blood flow, respectively. Millimeter wavelength exposure intensities used were high power (HP), 1 W x cm(-2) for 4 s and low power, 175 mW cm(-2) for 180 s. Skin blood flow was (a) normal, (b) eliminated using a blood pressure cuff to occlude forearm blood flow, or (c) elevated by heating the skin prior to irradiation. Results showed that for the HP exposures, these manipulations did not influence the rate of skin heating. For the low power exposures, occlusion of baseline skin blood flow had a small impact on the subsequent rate of heating. In contrast, a two-fold elevation in baseline skin blood flow had a profound impact on the subsequent rate of heating, resulting in a substantially lower rate of heating. Occlusion of an elevated skin blood flow reversed this lower rate of heating. The results of these studies demonstrate that relatively small changes in skin blood flow may produce substantial alterations in the rate of skin heating during prolonged 94-GHz exposure.

In the present study, the effects of photodynamic therapy (PDT) with verteporfin on tumor blood flow and tumor regrowth were compared as verteporfin distributed in different compartments within the RIF-1 tumor. Tissue distribution of verteporfin was examined by fluorescence microscopy, and blood flow measurements were taken with a laser Doppler system. It was found that, at 15 min after drug administration, when verteporfin was mainly confined within the vasculature, PDT induced a complete arrest of blood flow by 6 h after treatment. PDT treatment at a longer drug-light interval (3 h), which allowed the drug to diffuse to the tumor interstitium, caused significantly less flow decrease, only to 50% of the initial flow in 6 h. A histological study and Hoechst 33342 staining of functional tumor vasculature confirmed the primary vascular damage and the decrease in tumor perfusion. The regrowth rate of tumors treated with 15-min interval PDT was 64% of that of the control group. However, when tumors were treated with 3-h interval PDT, the regrowth rate was not significantly different from that of the control, indicating that only the 15-min interval PDT caused serious damage to the tumor vascular bed. These results support the hypothesis that temporal pharmacokinetic changes in the distribution of the photosensitizer between the tumor parenchyma and blood vessels can significantly alter the tumor target of PDT.

High-resolution near-wall fluorescent microparticle image velocimetry (micro-PIV) was used in mouse cremaster muscle venules in vivo to measure velocity profiles in the red cell-depleted plasma layer near the endothelial lining. micro-PIV data of the instantaneous translational speeds and radial positions of fluorescently labeled microspheres (0.47 microm) in an optical section through the midsagittal plane of each vessel were used to determine fluid particle translational speeds. Regression of a linear velocity distribution based on near-wall fluid-particle speeds consistently revealed a negative intercept when extrapolated to the vessel wall. Based on a detailed three-dimensional analysis of the local fluid dynamics, we estimate a mean effective thickness of approximately 0.33 micro m for an impermeable endothelial surface layer or approximately 0.44 micro m assuming the lowest hydraulic resistivity of the layer that is consistent with the observed particle motions. The extent of plasma flow retardation through the layer required to be consistent with our micro-PIV data results in near complete attenuation of fluid shear stress on the endothelial-cell surface. These findings confirm the presence of a hydrodynamically effective endothelial surface layer, and emphasize the need to revise previous concepts of leukocyte adhesion, stress transmission to vascular endothelium, permeability, and mechanotransduction mechanisms.

Repetitive transcranial magnetic stimulation (rTMS) of human primary motor cortex (M1) changes cortical excitability at the site of stimulation and at distant sites without affecting simple motor performance. The aim of this study was to explore how rTMS changes regional excitability and how the motor system compensates for these changes. Using functional brain imaging, activation was mapped at rest and during freely selected finger movements after 30 min of 1 Hz rTMS. rTMS increased synaptic activity in the stimulated left M1 and induced widespread changes in activity throughout areas engaged by the task. In particular, movement-related activity in the premotor cortex of the nonstimulated hemisphere increased after 1 Hz rTMS. Analyses of effective connectivity confirmed that the stimulated part of M1 became less responsive to input from premotor and mesial motor areas. Conversely, after rTMS our results were consistent with increased coupling between an inferomedial portion of left M1 and anterior motor areas. These results are important for three reasons. First, they show changes in motor excitability to central inputs from other cortical areas (as opposed to peripheral or exogenous inputs used in previous studies). Second, they suggest that maintenance of task performance may involve activation of premotor areas contralateral to the site of rTMS, similar to that seen in stroke patients. Third, changes in motor activations at the site of rTMS suggest an rTMS-induced remodeling of motor representations during movement. This remapping may provide a neural substrate for acute compensatory plasticity of the motor system in response to focal lesions such as stroke.

We studied the effects of 0.2 Hz repetitive transcranial magnetic stimulation (rTMS) successively performed 6 times for 2 weeks in 12 patients with idiopathic Parkinson's disease (PD). Ten patients received rTMS to the bilateral frontal cortex (frontal rTMS) and six patients received rTMS to the bilateral occipital cortex (occipital rTMS). Before and after rTMS, we evaluated regional cerebral blood flow (rCBF) using 99m-Tc-ECD single photon emission computed tomography (SPECT) and clinical tests. In an analysis with statistic parametric mapping, both frontal and occipital rTMS reduced rCBF in the cortical areas around the stimulated site. The activities of daily living (ADL) and motor scores of Unified Parkinson's Disease Rating Scale (UPDRS), pronation-supination movements, and buttoning up significantly improved after frontal rTMS than before it, while occipital rTMS had no significant effects in clinical tests.The findings of the present study suggest that successive 0.2 Hz rTMS has outlasting inhibitory effects on neuronal activity around the stimulated cortical areas. Because there were no significant relations between improved clinical tests and reduced rCBF, we speculate that the indirect effects of 0.2 Hz rTMS on subcortical structures are related to improved parkinsonian symptoms. Further studies recruiting large numbers of subjects are required to confirm the efficacy of 0.2 Hz rTMS on PD.

Ionizing radiation exposure significantly alters the structure and function of microvascular networks, which regulate delivery of oxygen to tissue. In this study we use a hamster cremaster muscle model to study changes in microvascular network parameters and use a mathematical model to study the effects of these observed structural and microhemodynamic changes in microvascular networks on oxygen delivery to the tissue. Our experimental observations indicate that in microvascular networks while some parameters are significantly affected by irradiation (e.g. RBC transit time), others remain at the control level (e.g. RBC path length) up to 180 days post-irradiation. The results from our mathematical model indicate that tissue oxygenation patterns are significantly different in irradiated normal tissue as compared to age-matched controls and the differences are apparent as early as 3 days post irradiation. However, oxygen delivery to irradiated tissue was not found to be significantly different from age matched controls at any time between 7 days to 6 months post-irradiation. These findings indicate that microvascular late effects in irradiated normal tissue may be due to factors other than compromised tissue oxygenation.

Purpose: We determined prostate perfusion in 18 patients with locally advanced prostate carcinoma treated with a combination of external beam irradiation and regional (10) or interstitial (8) hyperthermia., Materials and Methods: Perfusion values were calculated from temperature elevations due to constant applied power and from transient temperature measurements after a change in applied power. Student's t test was used for comparing perfusion values with time and in the 2 groups., Results: At the start of regional hyperthermia treatment mean estimated perfusion plus or minus standard deviation was 10 +/- 8 ml./100 gm. per minute. At the end of treatment mean perfusion was increased to 14 +/- 2 ml./100 gm. per minute (p <0.01). Achieved thermal parameters were a mean temperature of at least 40.3C +/- 0.6C in 90% of the prostate, 40.9C +/- 0.6C in 50% and a mean maximum temperature of 41.6C +/- 0.6C. At the end of interstitial hyperthermia treatment estimated mean perfusion was 47 +/- 5 ml./100 gm. per minute, which was significantly different compared with the end of regional hyperthermia (p < 0(-7) ). Mean temperature was at least 39.4C +/- 0.9C in 90% of the prostate and 41.8C +/- 1.6C in 50%, while mean maximum temperature was 53.1C +/- 6.3C. Systemic temperature increased during regional hyperthermia up to 38.6C, whereas during interstitial hyperthermia body temperature was not elevated., Conclusions: During interstitial hyperthermia perfusion values are higher than during regional hyperthermia. Hyperthermia causes increased prostate perfusion.

Purpose: To examine the retinal blood flow in normal eyes before and during retinal stimulation by flickering light., Design: A prospective cross-sectional study. PARTICIPANTS AND TESTING: Twenty-seven eyes of 27 normal subjects with a mean age +/- SD of 38 +/- 15 years (study I) and 21 eyes of 21 normal subjects with a mean age +/- SD of 46 +/- 17 years (study II) were examined with respect to capillary retinal blood flow and central retinal artery and central retinal vein blood flow velocities during flickering light stimulation. A luminance flicker light with a frequency of 8 Hz increased the neuronal activity of retinal ganglion cells. In study I, the retinal capillary blood flow was measured before and during flickering by scanning laser Doppler flowmetry (670 nm, Heidelberg Retina Flowmeter). In study II, the blood flow velocities in the central retinal artery and central retinal vein were examined by pulsed Doppler sonography., Main Outcome Measures: Change in blood flow velocities in the central retinal artery and vein and in retinal capillary blood flow after full-field flicker stimulation., Results: In study I, measurements of blood flow during retinal flicker stimulation showed a significant increase in the mean value of blood flow +/- SD from 317 +/- 72 arbitrary units to 416 +/- 103 arbitrary units. The change was on average 46 +/- 19%. In study II, the systolic and end-diastolic blood flow velocities in the central retinal artery increased significantly (P < 0.0001): systolic, 9 cm/s to 15 cm/s (+62%); end-diastolic, 2.7 cm/s to 5.3 cm/s (+96%). In the central retinal vein, the systolic and end-diastolic blood flow velocities increased significantly (P < 0.0001): systolic, 4.3 cm/s to 6.7 cm/s (+56%); end-diastolic, 1.8 cm/s to 3.6 cm/s (+100%). The authors found no significant change in blood pressure and heartbeat frequency., Conclusions: Visual stimulation of the retina by flickering light strongly increased the juxtapapillary retinal capillary blood flow and central retinal artery blood flow velocity in normal eyes.

Axial pattern skin flaps are a very important reparative tool for the plastic and reconstructive surgeon in the reconstruction of tissue defects. From whatever unfortunate reason, part or all of such flaps occasionally suffers from irreversible ischaemia with loss of the flap. Infrared diode laser therapy has been shown to improve local and systemic circulation. The present study was designed to assess the effect of an 830 nm diode laser (power density, 18.5 W/cm(2), energy density 185 J/cm(2)) on the blood flow of axial pattern flaps in the rat model and their survival, compared with unirradiated controls. The flaps were raised in all animals ( n=40), and blood flow assessed with laser speckle flowmetry (LSF). In the experimental groups (3 groups, n=10 per group), the flaps were irradiated either directly over the dominant feeder vessel (iliolumbar artery), at the proximal end or at the distal end of the flap itself and blood flow assessed during irradiation. Flowmetry was performed again in all animals at 5 and 10 min postirradiation, and the flaps sutured back in position. The unirradiated controls were handled in exactly the same way, but the laser was not activated. The survival rate of the flaps was assessed on the fifth postoperative day. LSF demonstrated significant increased blood flow in the flaps at 5 and 10 min postirradiation in all experimental groups compared with the control animals. At five days postirradiation, there was significantly better survival of the flaps in all the experimental groups compared with the controls ( p<0.01), but no significant difference was seen between any of the experimental groups. We conclude that laser therapy increases the blood flow and perfusion of transferred flaps, and that this has significant effects on the survival of the flaps. One possible mechanism of modulation of the autonomic nervous system is discussed.

Acute microhemodynamic effects of static and alternating magnetic fields at a threshold level were investigated on modulating the muscle capillary mirocirculation in pentobarbital-anesthetized mice. The skin in a tibialis anterior was circularly removed with 1.5 mm diameter for intravital-microscopic recording of the capillary blood velocity in the tibialis anterior muscle. Fluorescein isothiocyanate (FITC)-labeled dextran (MW 150 kDa) was used for an in vivo fluorescent plasma marker of the muscle capillaries. Following a bolus injection of FITC-dextran solution into the caudal vein, the peak blood velocity in the muscle capillaries was measured prior to, during, and following exposure to static magnetic fields (SMF) or 50-Hz electromagnetic fields (EMF) using a fluorescence epi-illumination system. The whole body of experimental animals, placed on the observing stage of a fluorescence microscope, was exposed to SMF (0.3, 1 and 10 mT) or 50-Hz EMF (0.3 and 1 mT) for 10 min using a specially devised electromagnet. For sham exposure, the electromagnet was not energized. During exposure and post-exposure to SMF of 10 mT, the peak blood velocity significantly increased as compared to sham exposure. After the withdrawal of SMF and 50-Hz EMF of 1 mT, significant similar effects on the blood velocity were present or enhanced. These findings suggest that field intensity of 1 mT might be considered as a threshold level for enhancing muscle microcirculation under pentobarbital-induced hypnosis.

There is a growing interest in performing intravascular interventions guided by MR imaging--a technique which offers the possibility of flow measurements during the intervention. For a reliable assessment of the haemodynamic significance of a stenosis, the flow and the pressure decay within the stenosis should both be measured. We have developed an optical, MR-compatible, pressure sensor (Annupres) that uses a novel annular element. Existing optical pressure sensors measure pressures unilaterally, thus giving rise to artefacts because of the dependence of the measurement on the angular orientation of the aperture. The annular element, however, measures blood pressure on all sides, and we show that by using circularly polarized light this pressure measurement is intrinsically insensitive to rotation of the sensor around its long axis. The Annupres sensor has been tested in an experimental set-up, and was able to measure pressures from 50 mmHg to 180 mmHg reliably with an accuracy of 1.5%.

Damage to the microvascular networks constitutes one of the most important components of ionizing radiation damage to normal tissue. Previously, we have reported the early (3, 7 and 30 days postirradiation) effects of ionizing radiation on the structure and function of normal tissue microvascular networks. Here we report on the late effects of ionizing radiation on the structural and functional changes in microvascular networks in locally irradiated (single 10-Gy dose) hamster cremaster muscles observed 60, 120 and 180 days postirradiation; age-matched animals were used as controls. As in the previous study, intravital microscopy was used to measure structural and functional parameters in complete microvascular networks in vivo. A factorial design was used to examine the effects of radiation status, time postirradiation, and network vessel type on the structure and function of microvascular networks. Our results indicate that the progression of radiation-induced microvascular damage continues during the late times but that there is partial recovery from radiation damage within 6 months postirradiation. Red blood cell flux, red blood cell velocity, and capillary blood flow in irradiated networks at 180 days postirradiation were significantly greater than control levels. As at the early times, all vessel types were not damaged equally by radiation at every time.

We have conducted experiments to clarify the existence of extraretinal photosensitivity in mammals through the measurements of skin blood flow variation due to light irradiation. We found that blood flow shows a synchronized transient increase with a irradiation-nonirradiation sequence. The action spectrum of the phenomenon was found to show peaks at approximately 410-420 nm, 540-550 nm, and 570- 580 nm. These peaks coincide with the specific optical absorption peaks of B and Q (alpha,beta) bands in sixfold coordinated ferruos-heme complexes such as nitric oxide (NO)-Hb. The blood flow increase in the irradiated duration disappears when the rats are intraperitoneally injected with 1H-[1,2,3]oxydiazolo[4,3-a] quinoxalin-1-one (ODQ), which is an inhibitor of guanylate cyclase, and N(G)-monomethyl-L-arginine acetate and N(G)-nitro-L-arginine methyl ester, which are inhibitors of NO synthase. On the basis of the present results, we propose a photochemical model of the photosensitivity mechanism where optical absorption of the sixfold coordinated ferrous heme-NO complex plays a main role.

Purpose: To document the response of subfoveal choroidal blood flow (ChBF) in the human eye induced by light and dark exposures and provide some insight into the mechanism underlying this response., Methods: In a group of 12 volunteers (age, 25-60 years), ChBF was measured with a confocal laser Doppler flowmeter. Wavelength of the probing laser beam was 785 nm (90 microW at the cornea). ChBF was recorded in room light, in darkness, in room light after dark adaptation, and during strong green light exposure after exposure to room light. After dark adaptation of both eyes, ChBF was also measured in one eye while only the fellow eye was exposed to strong visible light., Results: Although ChBF was stable during room light condition, it decreased significantly by 15% (P < 0.01) during dark adaptation. After 6 minutes of room light following 20 minutes of darkness, ChBF was back to baseline. Strong, diffuse, green light exposure over a field of 40 degrees, as well as the probing laser beam, had no detectable effect on ChBF. No change in ChBF was detected when the fellow eye was illuminated after both eyes had been dark adapted., Conclusions: The findings did not confirm the presence of an active process of ChBF regulation in response to light exposure in humans. They demonstrate, however, a reversible decrease in ChBF that occurs after a transition from room light to darkness, which could involve a neural mechanism.

Purpose: To investigate the effect of the oral administration of evening primrose oil on the radiation response and the blood flow of normal tissue and a tumour in BALB/c mice., Methods and Materials: Aliquots of evening primrose oil were fed to BALB/c mice daily and the radiation response of the skin was assessed by the determination of ED50 values for the incidence of moist desquamation, using probit analysis. Tumour radiosensitivity was investigated by determining the growth delay caused by irradiation of a transplantable rhabdomyosarcoma. The 86RbCl uptake technique was used to determine the blood flow in normal foot and tumour tissue. The fatty-acid content of red blood cells, plasma and tumour tissue was measured using gas chromatography., Results: Daily evening primrose oil dietary supplementation reduced the sensitivity of skin to radiation-induced moist desquamation and prevented the radiation-associated increase in blood flow that was observed in this tissue. No modification of tumour blood flow or of tumour sensitivity to radiation resulted from evening primrose oil supplementation of mice. Evening primrose oil supplementation resulted in changes in plasma levels of linoleic acid (LA), gamma-linolenic acid (GLA), dihomo-gamma-linolenic acid (DGLA) and arachidonic acid (AA). These changes were contingent on whether the mice had been irradiated or not. In red blood cells evening primrose oil supplementation increased the GLA level of unirradiated mice and the LA level at 20 days after irradiation. There were no changes in tumour fatty-acid levels as a result of evening primrose oil treatment., Conclusions: Daily evening primrose oil supplementation reduced the sensitivity of skin to radiation-induced moist desquamation but did not alter tumour sensitivity to radiation.

Fifty-one elderly patients with maculodystrophy were observed and treated. Exposure to electric field of 1-2 mV/cm and 40-57 Hz led to improvement of microcirculation in the fundus oculi and decreased vision disorders.

Objective: We investigated the relationship between bronchial mucosal blood flow around the area of lung resection and the state of healing of the bronchial stump in patients after chemotherapy with or without radiation therapy., Methods: Ninety patients with primary lung cancer were divided into the following 3 groups: group A, 72 patients who had no preoperative therapy; group B, 10 patients who had chemotherapy; and group C, 8 patients who had chemoradiation (60 Gy) therapy. Bronchial mucosal blood flow was measured preoperatively, intraoperatively, and postoperatively (days 8-10) with a laser Doppler flowmeter., Results: In groups A and B bronchial mucosal blood flow was preserved sufficiently around the surgical site, and the healing of the bronchial stump was satisfactory. On the contrary, preoperative blood flow in group C was 70% of the preoperative value in group A and decreased further intraoperatively. Healing of the bronchial stump was poor, and a bronchopleural fistula occurred in one patient of group C., Conclusion: Preoperative chemoradiation therapy may adversely affect bronchial mucosal blood flow and healing of the bronchial stump, although lymphadenectomy and preoperative chemotherapy had little effect. It is recommended that the bronchial stump should be covered with pedicled viable tissue after chemoradiation therapy for prophylaxis against bronchial complications.

Background and Objective: The aim of study this was to evaluate in vivo the pulpal blood flow rate, pulpal responsiveness, systemic blood pressure, and pulse rate during Nd:YAG laser irradiation of an isolated tooth., Study Design/materials and Methods: Thirteen volunteers from the Tsurumi Dental University faculty participated in this study after giving their consent to the Nd:YAG laser irradiation test protocol. Gingivobuccal areas adjacent to mandibular canines were used for clinical evaluation. Each area was coated with India ink and treated with a Nd:YAG laser for 30 sec at 120-mJ pulses at 10 pulses/sec. Pulpal blood flow was measured by a laser Doppler flowmeter during Nd:YAG laser irradiation of the tooth. All pulp responses were measured by an electric pulp tester before and after Nd:YAG laser irradiation. In addition, the systemic blood pressure and pulse rate were monitored throughout the laser irradiation procedure., Results: For all subjects involved in this study, the pulpal blood flow rate increased during laser irradiation. Threshold values of the electric pulp tests increased in six cases and decreased in six cases. One case showed no change. After 1 month, the threshold values for each subject had returned to previously recorded values. Neither systemic blood pressure nor pulse rate was affected during Nd:YAG laser irradiation. Pulpal blood flow was strongly influenced immediately after Nd:YAG laser irradiation, seen as an increase in the flow rate., Conclusion: The results of this study suggest that effects of the Nd:YAG laser irradiation are similar to those of low power laser for the improvement of local blood flow., (Copyright 2000 Wiley-Liss, Inc.)

Background and Objective: Recently, there has been an increase in the clinical application of low-level laser irradiation (LLLI) in various fields. The present study was conducted to explore the effects of LLLI on microcirculation., Study Design/material and Methods: We investigated the effects of LLLI on rat mesenteric microcirculation in vivo, and on cytosolic calcium concentration ([Ca2+]i) in rat vascular smooth muscle cells (VSMCs) in vitro., Results: LLLI caused potent dilation in the laser-irradiated arteriole, which led to marked increases in the arteriolar blood flow. The changes were partly attenuated in the initial phase by the superfusion of 15 microM L-NAME, but they were not affected by local denervation. Furthermore, LLLI caused a power-dependent decrease in [Ca2+]i in VSMCs., Conclusion: The circulatory changes observed seemed to be mediated largely by LLLI-induced reduction of [Ca2+]i in VSMCs, in addition to the involvement of NO in the initial phase.

Aims: To evaluate the effect of high dose stereotactic radiotherapy on the ocular blood flow of patients with uveal melanoma., Methods: Colour Doppler imaging (CDI) was used to measure blood flow velocity and vascular resistance in the ophthalmic, short posterior, and central retinal arteries of nine patients suffering from uveal melanoma. The measurements were taken before, 6 months, 1 year, and 2 years after stereotactic radiotherapy. Irradiation was performed with the Leksell gamma knife with the 59 (41-66.5) Gy total marginal dose divided in two equal fractions. CDI results were compared with age and sex matched healthy control eyes., Results: At each time of measurement, blood flow velocity in the central retinal artery of the affected eyes was significantly reduced whereas vascular resistance was only increased at the 2 year follow up. Blood flow velocity and vascular resistance in the short posterior arteries of melanoma eyes were also only significantly altered at the 2 year follow up. Blood flow velocity and vascular resistance in the ophthalmic artery of melanoma eyes were not changed at all follow ups., Conclusions: In the melanoma eyes, blood flow velocity in the central retinal artery is reduced. High dose stereotactic radiotherapy with the Leksell gamma knife and a 59 (41-66.5) Gy total marginal dose in two fractions leads to a significant reduction of blood flow and a significant increase in resistance variables in the small ocular arteries within 2 years.

Combination of radical excision and radiation has been used as a treatment modality for cancer patients. As a result, in reconstructive surgery there is often a need to harvest flaps in the vicinity of previously irradiated tissues. Radiation has been shown to cause progressive injury to the macrocirculation and microcirculation, often jeopardizing flap survival. The purpose of this study was to examine whether radiation significantly affects the sequence of leukocyte-endothelial interactions or the hemodynamics of the muscle flap in both acute and chronic situations. Male Sprague-Dawley rats (n = 42) were divided into seven groups of six rats each. Rats in group I were not irradiated. Groups II through VII received 8-Gy radiation to the right groin and scrotum. Groups II, III, and IV were examined at 4, 24 and 72 hours, respectively, and groups V, VI, and VII were examined at 1, 2 and 12 weeks. For intravital microscopy, the cremaster muscle was dissected on its neurovascular pedicle. Vessel diameters and red blood cell velocities were measured in the central cremasteric branches and branch arterioles. Capillary perfusion was evaluated in 27 visual fields of each flap. Leukocyte-endothelial interactions were evaluated by numbers of rolling, adhering, and transmigrating leukocytes in post-capillary venules. In the same postcapillary venule, we measured the endothelial edema index (constriction index). The hemodynamics of irradiated flaps did not differ significantly from those of controls. Diameter and red blood cell velocity were increased in the first- and second-order arterioles and were highest at 72 hours and 1 week. After irradiation, third-order arterioles were constricted. Radiation reduced capillary perfusion by 4.3, percent. None of the differences were statistically significant. Neither leukocyte behavior nor the constriction indices differed among the groups. In conclusion, low-dose radiation of 8 Gy does not affect hemodynamics or leukocyte-endothelial interactions of muscle flaps in the rat. Muscle tissue with intact microvasculature can be harvested for reconstructive procedures after low-dose radiation.

Introduction: The biophysical properties of microwave electromagnetic radiation suggest that it may be an alternative to radiofrequency (RF) energy for ablation of arrhythmias resistant to treatment using RF ablation., Methods and Results: The aim of this study was to characterize lesions produced using simple element designs in a blood superfused ovine tissue model to simulate endocardial ablation. The effect of tissue bath flow, duration of microwave exposure, and changes in forward power on lesion size were examined using a modified monopole element. Lesion size increased with increasing duration of exposure and increasing forward power (P < 0.05). Lesion depth was 0.7+/-0.7 mm after 30 seconds and 11.5+/-1.9 mm after 360 seconds. Lesion depths at 61, 71, and 80 W were 6.4+/-3.7, 8.9+/-2.0, and 11.9+/-1.2 mm, respectively. Altering flow within the bath from 3 to 5 L/min did not significantly change lesion size., Conclusion: Simple element designs can be used to produce a range of lesions from very small sizes to lesions that are transmural in the ventricle. The temperature half-time for microwave ablation is far greater than that of RF ablation. Like RF lesions, the lesions produced by microwave ablation have greater width than depth. Deep penetration of lesions into the ventricular myocardium can only be achieved with these elements by producing lesions of perhaps unnecessarily large volume.

Background and Objective: Simultaneous irradiation and viewing of 10-120 microm cutaneous blood vessels were performed to investigate the effects of 2-micros 577-nm dye laser pulses., Study Design/materials and Methods: A modified scanning laser confocal microscope recorded vessel response to different radiant exposures (J/cm2). Probit analysis determined the 50% probability ("threshold") radiant exposure necessary to cause embolized or partly occluding coagula, coagula causing complete blood flow stoppage, and hemorrhage., Results: A statistically significant difference in the threshold radiant exposure existed for each damage category for blood vessels 10-30 microm in diameter, but not for larger vessels. For vessels over 60 microm, complete flow stoppage was unattainable; increasing laser pulse energy produced hemorrhage. In larger vessels, coagula often were attached to the superficial vessel wall while blood flowed underneath. Monte Carlo optical and finite difference thermal modeling confirmed experimental results., Conclusion: These results provide insight into the role of pulse duration and vessel diameter in the outcome of pulsed dye laser irradiation.

PUVA and UVB phototherapies are used in the treatment of psoriasis and other inflammatory skin diseases. Ultraviolet radiation causes inflammation and modulates cell kinetics in the skin. PUVA also has an inhibitory effect on skin DNA synthesis. In this study, the effects of PUVA and UVB treatments on epidermal would healing were examined using the suction blister wound model. The healing of the wound was studied indirectly by measuring water evaporation and blood flow in the wound area. On the fourth day, water evaporation was more abundant in PUVA-treated patients (42 +/- 5 g/m2h) than in UVB treated (36 +/- 4 g/m2h) or control patients (27 +/- 3 g/m2h) (analysis of variance, the least significant difference test at a level of 0.05). The P value for the difference of means between the PUVA and control groups was 0.014. Blood flow was also more abundant during the fourth (PUVA 162 +/- 11 arbitrary units, UVB 122 +/- 10, controls 115 +/- 15) and sixth (PUVA 108 +/- 18, UVB 73 +/- 17, controls 57 +/- 13) day in PUVA treated patients (analysis of variance, the least significant difference test at a level of 0.05). The results suggest that PUVA treatment decreases the restoration of the epidermal barrier function. The PUVA-treated patients also showed a more intense and prolonged vascular response that may be due to PUVA-related inflammation.

Background/aims: Anastomoses in previously irradiated intestine are prone to leakage, possibly due to an impeded blood supply. Whether or not chronic radiation damage actually predisposes to a disturbed blood flow in the vicinity of anastomoses was investigated in the rat small bowel., Method: A 2-cm segment of rat ileum was irradiated with a single dose (21 Gy). After 20 weeks an anastomosis was created in the irradiated segment and in the corresponding segment of controls. Another 4 days later local blood flow was studied with the 14C-iodoantipyrine autoradiography technique in 16 sectors around the circumference both in the anastomotic segment and in a segment 4 mm apart., Results: In the anastomotic segment, the average blood flow was reduced in irradiated compared with non-irradiated animals in the mucosal layer (p = 0.034), but not in the muscular layer (p = 0.08). In the mesenteric quadrant blood flow was reduced in irradiated compared with non-irradiated animals, both in the mucosal layer (p = 0.012) and in the muscular layer (p = 0.05). More irradiated than non-irradiated animals showed a blood-flow reduction to 15% or more in 13-16 sectors both in the mucosal (p = 0.015) and the muscular layer (p = 0.04)., Conclusions: The results favor the hypothesis that anastomoses in previously irradiated intestine are vascularly compromized and thereby have an increased risk of leakage.

Purpose: To characterize the glucose metabolism in the rabbit retina., Methods: An artery and a vortex vein were cannulated. Arteriovenous differences in oxygen, lactate and glucose concentrations, and blood flow were determined during either 1) darkness and light, or 2) light and 4 Hz flickering light., Results: In darkness, oxygen consumption, glucose consumption, and lactate formation were 0.122 +/- 0.014, 0.204 +/- 0.015 and 0.160 +/- 0.023 micromol/min (mean +/- SE), respectively. Constant light reduced oxygen consumption insignificantly, and had no effect on glucose consumption. Hyperoxia did not affect the lactate formation. Flickering light increased the glucose consumption and lactate formation by 15-20%., Conclusions: In rabbits, 10% of the glucose consumed is oxidized, 40-50% is metabolized to lactate and the rest is used for other purposes. The glycolysis is primarily aerobic. Flickering light increases the glucose metabolism, constant light having little effect.

Purpose: To elucidate the role of nitric oxide (NO) in the eye and the flicker-induced vascular response., Methods: The blood flow in the retina and different parts of the optic nerve was compared in cats treated with the NO-synthase blocker, N(G)-nitro-L-arginine methyl ester and in control animals. In both groups, one of the eyes was dark-adapted, the other was subjected to 8 Hz flickering light. The regional blood flow was measured with the microsphere method., Results: In control animals, flickering light increased blood flow in the retina and optic nerve head by 39% and 256%, respectively. Pretreatment with N(G)-nitro-L-arginine methyl ester prevented this increase in retinal blood flow and markedly reduced the blood flow in the optic nerve heads., Conclusion: NO release may mediate much of the vasodilating effect of flicker in cats, and play a role in maintaining normal vascular tone in the optic nerve head.

Hemodynamic parameters such as total cerebral blood volume (total CBV), cerebral parenchymal blood volume (CBV), cerebral blood flow (CBF) and cerebral blood velocity index were measured in rats 6, 12 and 18 months after single exposures of brain to 5, 10, 15 and 20 Gy X rays for total CBV, CBF and blood velocity index, and only 20 Gy for CBV. Total CBV and blood velocity index were determined by a noninvasive blood dilution method using [99mTc]pertechnetate and CBF by [131I]iodoantipyrine brain extraction. The CBV was obtained from both parenchymal plasma and erythrocyte volumes measured in isolated brain by 125I-labeled serum albumin and 51Cr-labeled erythrocytes, respectively. Neither the dose nor the time after irradiation influenced total CBV. Nevertheless, CBV decreased slightly while CBF decreased strongly at 12 and 18 months after 20 Gy. In contrast, the blood velocity index increased progressively at 12 and 18 months after 15 Gy and at all times after 20 Gy. According to the coexistence in irradiated brains of a remodeling with microvascular occlusions and dilated abnormal vessels, this lowered CBF can be explained by the smaller number of open capillaries and a "steal phenomenon" through low-resistance channels developed in the parenchymal and extraparenchymal vasculatures. Such a "steal phenomenon" is also supported by the response of the blood velocity index, which appears to be the earliest sensitive index for the detection of hemodynamic changes with respect to time (6 months) and dose of radiation (15 Gy).

The subjects were exposed to bright or dim light during the daytime. Compared to dim light exposure, bright light exposure induced a steeper slope in the regression line between the skin blood flow of the forearm and mean body temperature under an external heat load in the evening.

We investigated the temperature distribution, early histological changes, blood brain barrier (BBB) disruption and sequential changes in cerebral blood flow (CBF) following hyperthermia ranging from 37 to 45 degrees C in a new rat model of radiofrequency-induced localized cerebral hyperthermia. Significant histological changes and BBB disruption were observed in brain regions heated to 43 degrees C and above. In the cortex heated to 41 degrees C, the CBF doubled 20 min after hyperthermia induction, and then returned gradually to the pre-hyperthermic level. In the cortex heated to 43 degrees C, the CBF increased to 134% of the baseline level 10 min after hyperthermia induction, and then fell gradually to reach its minimum level (31% of the baseline level). In the cortex heated to 45 degrees C, the CBF decreased immediately after hyperthermia induction to reach 10% of the baseline level. The results indicate that hyperthermia-induced cellular injury in the central nervous system is associated with cerebral ischaemia and the threshold temperature for such injury is 43 degrees C. This model is useful for investigating the effects of hyperthermia on various cerebral functions and the CBF changes demonstrated in the present study may provide key information for the analysis of other cerebral functions.

Background: This study was designed to evaluate radiation-induced changes in tumor blood flow by color Doppler ultrasonography., Methods: Color Doppler examination was performed on 14 patients with advanced cervical carcinoma treated with external radiotherapy. The total dose of radiation varied from 30 to 65 Gy and was given as 1.9 Gy daily fractions, 5 days/week. Tumor vascularity and blood flow impedance were measured by one pretreatment and five follow-up examinations., Results: At the baseline examination, 11 of 14 patients had very low tumor blood flow impedance (< 0.70). Radiotherapy caused a significant decrease in tumor vascularity (P = 0.0001) and in presence of very low blood flow impedance. The decrease of tumor vascularity during the treatment was associated with better outcome, whereas persistence of excessive vascularity or of vessels with low blood flow impedance at the end of radiation was associated with modest therapeutic response. Eight of 10 patients with increased tumor vascularity at the end of radiation needed further treatment or died of disease. Only one of four patients with normal vasculature at the end of radiotherapy needed further treatment and all four were clinically disease free during the follow-up (mean, 13 months; range, 6-26 months)., Conclusions: These results suggest that color Doppler ultrasonography may be useful in early assessment of therapeutic response during radiotherapy and in for planning individualized treatment schedules.

The effect of ionizing radiation on jejunal blood flow was investigated in rats receiving whole-body exposure to 10 Gy gamma-radiation. Irradiation resulted in increased myeloperoxidase activity, indicative of neutrophil infiltration, and prostaglandin E2 synthesis by 2 h post-irradiation, but had no effect on leukotriene B4 synthesis. In ex vivo intestinal chamber studies, exposure to radiation reversed the mucosal-submucosal blood flow changes elicited by intravenous administration of leukotriene C4 (1 microgram.kg-1.min-1 for 10 min) or endothelin 1 (1 microgram.kg-1.min-1 for 5 min), but not that elicited by topical capsaicin (100 or 640 microM), as measured by laser Doppler flowmetry. The effect of radiation on vascular responses to leukotriene C4, but not those to endothelin 1, was reversed by pretreatment of the rats with the cyclooxygenase inhibitor, indomethacin (5 mg/kg). There was no significant effect of irradiation on mean arterial pressure or on ion or protein effluxes into the chamber bathing solution, nor did irradiation alter transmural potential difference. These studies point to altered responsiveness of the jejunal mucosal-submucosal vasculature shortly after exposure to ionizing radiation. Changes in function could reflect the onset of an acute inflammatory response, and appear to have cyclooxygenase-dependent and -independent components.

Blood flow pattern (maximum moment velocity, mean velocity, artery diameter and minute flow) in the superficial femoral artery and in the foot artery was evaluated in 30 patients, subjected to laser biostimulation for symptoms of atherosclerotic ischemia of the lower limbs. The blood flow examination was performed before the treatment and immediately afterwards (20 procedures) and 6 months following the therapy. It was found that laser biostimulation had a favorable effect on the blood flow pattern, particularly in the initial stage of ischemia (Io), and may be a useful method of medical treatment in atherosclerotic ischemia of the lower limbs.

Basing on analysis of clinical cases, the authors make suggestions on clinical and laboratory examinations and comprehensive pathogenetic therapy of patients with acute and chronic nonspecific inflammation of the salivary glands making use of low-energy He-Ne laser. Good results were attained in 95% of patients. The most marked effect of comprehensive treatment was observed when 5 min laser exposure at irradiation power of 0.8 to 1.3 mWt/cm2 was used.