The clinical application of low incident levels of laser energy is appearing more frequently in the literature. Actually low powered laser, for example diode laser, has been used for pain control, healing of incurable ulcers, flap survival and any other various therapies. But the mechanism of laser action has not been cleared yet. This time we had some interested knowledge with animal models. Island flaps, caudal based axial pattern flaps whose feeding arteries were superficial epigastric arteries, were raised on the abdominal wall of two groups of male Wister rats, 20 animals in each group. The flaps were immediately sutured back in place. One group acted as control with no irradiation, and other group received radiation from the gallium aluminium arsenide (Ga Al As) diode laser, 830nm, 60mW, continuous wave, and at an energy density of 240J/cm2 at one point on the flap base, total energy was 3.6J per one irradiation.
Both blood flow and mass were increased following one minute irradiation of diode laser for the feeding arteries of the flaps, and after one weak the area of flap survival was macroscopically enlarged as compared with the control group. We conjectured that there were some systems in the mechanism of the laser action, those of autonomic nervous systems, to a certain extent.
From those facts the application of low powered laser for the flaps immediately after operation, especially in our field, must aid in the faster and better take of the flaps.

View full abstract

This study was designed to investigate the effects of low power laser irradiation on vascular smooth muscle in various wavelengths and intensities.
Ring segments of rat thoracic aorta were mounted isometrically with 2g resting tension in 60ml Krebs buffer. Vascular ring precontracted with norepinephrine (1×10^-6M) was irradiated with an argon ion laser (351nm, 514.5nm) or a Ti: Sapphire laser (800nm) towards its endothelial surface for 60 seconds via a 200μm core optical fiber. In addition, temperature at the laser-irradiated point was measured.
The 351nm laser irradiation at the power between 2 and 10mW induced vascular relaxation less than 1.0g in each case. The 800nm irradiation at the power over 80nm caused power-dependent contraction less than 0.1g. The vascular segment irradiated with the 514.5nm irradiation showed either power-dependent contraction less than 0.1g or relaxation less than 1.0g at the power more than 160 mW. Tissue-temperature rise was 2.91°C at 351nm irradiation (60mW), 1.90°C at 514.5nm irradiation (500mW) and 3.35°C at 800nm irradiation (600mW).

View full abstract

We previously observed that vascular rings of rat thoracic aorta irradiated with Argon ion laser (λ=514.5nm) reproduciblly showed either contraction or relaxation. To study the mechanism of the contraction, vascular contraction induced by laser irradiation in Krebs buffer was compared with that in the following solutions: 1)Ca-free 10mM-EGTA containing buffer; 2)Krebs buffer with 5mM procaine; 3)Ca-free EGTA containing buffer with 5mM procaine. Vascular rings were suspended isometrically with 2.0g tension and irradiated via optical fiber(φ=200μm) into the vascular ring. In each solution, the irradiated vascular ring contracted with same character. These results suggest that vascular contraction due to laser irradiation is independent of the extracellular Ca²⁺ influx and/or Ca²⁺ release from sarcoplasmic reticulum.

View full abstract

Low power laser irradiation (LPLI) has been suggested to have various biological effects, but there are few reports about effects of direct LPLI to the brain. In the brain, cholinergic pathways are suggested to play a role in learning and memory functions. The medial septal nucleus and the vertical limb of diagonal band of Broca (septal complex) provide the major cholinergic projection to the hippocampus (Hpc), and the septal complex stimulation is reported to increase neural activities and local cerebral blood flow (LCBF) in the Hpc. The present study examined the effect of LPLI to the septal complex on the Hpc-LCBF. Adult male of Wistar strain rats were maintained under controlled lighting (lights on 5:00-19:00h) and temperature (24°C), and allowed free access to food and water. A 200-mm diameter polyurethane-coated platinum electrode with a 1-mm bare tip for measurement of LCBF and a stainless steel guide cannula for LPLI were introduced stereotaxically into the dorsal Hpc and the septal complex, respectively. The LCBF was measured by the hydrogen clearance method in freely moving rats. During LPLI, Hpc-LCBF increased by approximately 20% (p<0.01) as compared with the pretreatment control level, and kept an approximately 10% increase for 30 min after the LPLI. These results suggested that the LPLI enhanced the activity of cholinergic neurons in the septal complex and then caused an increase in the Hpc-LCBF.

View full abstract

We studied the effect of low power laser on the functional wound healing process at the site of anastomosis in the rat. Tracheal reconstruction was performed after the tracheal transection and He-Ne laser (3.3×10^-3W/cm2, 5min) was irradiated to the site of anastomosis. The mucociliary function and microstructure were evaluated at 3, 7 and 14 days postoperatively.
The degree of functional recovery in the irradiated group was better than that of non-irradiated group. Among the cases which showed the structural recovery of cilia with the scanning electron microscope, the functional recovery was observed in whole irradiated group, and in 40% of non-irradiated group.
From this study, it was suggested that the He-Ne laser irradiation may promote the recovery of mucociliary function at the site of anastomosis.

View full abstract

There are branches of spinal nerves, in the interspinal section.
I reached the following conclusion by the immediate effects of the Low Power Laser irradiation to the sharpest tender point among the interspinal section that must be concerned with complaint.
1) The effective percentage for 24 cases in 8 patients: (more effective cases+effective cases)÷all cases×100% was 62.5%.
2) In the 2 cases of scapulohumeral periarthritis, the sick arms could be moved much more in flexion and more in abduction than before.
3) I think that if we add this therapy to the usual one, the improvement of remedical value is expected.

View full abstract

Since 1984 my institutes have been studying the efficacy of low reactive-level laser therapy (LLLT) in pain attenuation using the 830 nm GaAlAs diode laser, and I have presented regular updates at various national and international congresses. We use the'Luketron'system, researched and developed by the Japan Medical Laser Laboratory and Matsushita Electric Company, and currently marketed by Mochida Pharmaceutical Company. Laser energy at 60 mW, 830 nm in continuous or switched wave is easily delivered by a hand-held probe used in contact with the target tissue. Our average effective rates are always over 85%. Having studied LLLT data from other clinics and hospitals, however, we have found that the results from these clinics vary with some pain entities resistant to LLLT. 3 years ago we opened an annex to our main clinic about 30 minutes away by car, where we applied the same LLLT techniques for pain attenuation, but the overall efficacy rate a year ago was surprisingly poor, 75%. However, we reviewed and improved the therapists'attitude and level of enthusiasm, since we believed the problem lay there, and after a further year the overall efficacy rose to 89.7%. In the main hospital, due to the removal of a hospital ward, we have been able to construct a new laser therapy facility of some 32 tsubo (approximately 64 m2). We have designed an open, spacious and warm environment, with a decor relying on natural wood and greenery, in which 6 laser therapists can work to a selection of appropriate BGM. In addition to laser therapy, another 3 types of pain attenuation system are employed, thus using patients' waiting time to the maximum efficiency. Preliminary findings indicate even better results in pain attenuation, showing that a good environment combined with the use of appropriate conventional methodologies can enhance the efficacy of LLLT.

View full abstract

We irradiated LPL 3-4 times a week at acupuncture points (4 points at the head) of 32 SD patients. (20 cerebrovascular disease type, 12 Alzheimer type)
A group; 4 months irradiation, B group; 2 months irradiation 1 month rest and 1 month irradiation, C group; 2 months irradiation and 2 mopnths rest.
SD levels of all patients were evaluated using 4 kinds of scales such as Hasegawa, ADL, standing balance and walking speed at the start of test and at the end of each month 5 times in total.
We found statistically significant difference between the SD level of A and C group in the combined score of 4 scales, ADL and speed being suggested the efficacy of LPL therapy for SD patients. There were no statiscally significant difference between cerebrovascular disease type and Alzheimer type groups and slight class and middle class SD groups.

View full abstract

We irradiated LPL on two patients with dementia of Alzhemer type and one patient with alcoholic dementia after obtaining informed consent from the patients and their families. The results were analyzed for clinical symptoms and changes in SPECT.
LPL therapy was used for this study in which a total of four sites: the forehead, the right and left temples, and the occiput were irradiated. The irradiation time was two minutes per site (10_m, watts), and the number of irradiation was two to four times per 1 week. To clearly determine whether therapeutic effects were attributed to this laser therapy, the following factors were set: Circumstances were fixed for a month, and medication was kept to the minimum necessary level. Under these conditions, the following was observed: symptoms of dementia advanced gradually in the chronic stage prompting the patient's care to last more than three months. Among the changes in clinical symptoms common among the patients were fewer emotional disturbances and slight improvement in short and middle term memory disturbances.
A comparison of the first SPECT just before laser therapy with SPECT conducted one to three months after laser therapy clearly showed improvement in only one patient. In the patient who showed improvement in SPECT, improvement in blood circulation was observed in the order of the basal nucleus, the thalamus, the lower part of the frontal lobe and the temporal lobe.

View full abstract