Circulation |
Effects Of Near-Infrared Low-Level Laser Irradiation On Microcirculation
Maegawa Y, Itoh T, Hosokawa T, Yaegashi K, Nishi M.
Lasers Surg Med. 2000; 27:427- 437.
The present study was conducted to explore the effects of LLLI on microcirculation. 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. 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. 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.
Effects Of 780 Nm Diode Laser Irradiation On Blood Microcirculation – Study By Time
Dependent T1-Wieghted Enhanced Magnetic Resonance Imaging (MRI)
Schaffer M et al.
Six healthy volounteers were irradiated on their right pianta pedis with 5J/cm2 and a fluence rate
of 100 mW/cm2. T1-weighted MRI was used to quantify the time-dependent local accumulation of Gadolinium DPTA, which semi-quantitatively reflects local blood flow. Images were obtained
before and after laser application. LLLT resulted in an increase of signal to noise ratio of more
than 0.34 (range 0.23-0.63) after irradiation according to contrast enhanced MRI. Increased blood flow offers an explanation for the clinical observation of improved wound healing and reduced pain after LLLT. The effect might complete and improve the outcome of other therapeutic
modalities such as tumor ionizing radiation therapy and local chemotherapy.
Cerebral Vascular Effects Of Non-Invasive Laserneedles Measured By Transorbital And
Transtemporal Doppler Sonography
Litscher G, Schikora D.
Department of Biomedical Engineering and Research in Anesthesia and Critical Care,
University of Graz, Austria. gerhard.litscher@uni-graz.at
Lasers Med Sci. 2002;17(4):289-95.
Laserneedles represent a new non-invasive optical stimulation method which is described for the
first time in this paper. We investigated 27 healthy volunteers (mean age+/-SD: 25.15+/-4.12
years; range: 21-38 years; 14 female, 13 male) in a randomised cross-over trial to study
differences between laserneedle acupuncture and manual needle acupuncture in specific
cerebral parameters. Mean blood flow velocity (v(m)) showed specific and significant increases in
the ophthalmic artery during laserneedle stimulation (p=0.01) and during manual needle
stimulation ( p<0.001) at vision-related acupoints. At the same time insignificant alterations in
v(m) were found in the middle cerebral artery for both acupuncture methods.
The eight laserneedles used in this study were arranged at the end of the optical fibres. Each
fibre was connected to a semiconductor laser diode emitting at 685 nm with a primary output
power of about 55 mW. Optical stimulation using properly adjusted laserneedles has the
advantage that the stimulation can hardly be felt by the patient and the operator may also be
unaware of whether the laserneedle system is active, and therefore true double blind studies in
acupuncture research can be performed.
In An Animal Study By Kobayashi The Effect Of Gaalas Laser On The Blood Flow In Flaps
Was Studied Through Laser Speckle Flowgraphy (LSF) 40 rats were divided into four groups. Two groups had random pattern flaps, two had axillary pattern flaps with the dominant vessels intact. Flaps were raised and peripheral blood flow
assessed through LSF. Laser irradiation was performed in two groups, either directly on the
dominant vessel or at one point on the distal part of the flap. The blood flow directly after
irradiation was higher than before irradiation. At day 5 there was a clear difference between the
irradiated and the non-irradiated flaps. The flaps irradiated at the dominant vessels had a slightly
better outcome than those irradiated at the Kobayashi M et al. Studies of the diode laser therapy on blood supply in the rat model. Proc. 2nd Congress World Assn for Laser Therapy, Kansas
City, September 1998; p. 70-71.
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