The calcaneal tendons of 31 rabbits were tenotomized, repaired and immobilized in order to determine the effects of treatment intervention time on tensile strength, tensile stress, energy absorption capacity, and stress-strain characteristics of regenerating tendons treated with laser. Healing tendons were treated transcutaneously with 0.5J/cm² GaAs laser either on postoperative days 1-14 (group one), 1-7 (group two), or 8-14 (groups three). Control tendons (group four) were similarly tenotomized and repaired but not treated with laser. Using initial body weight and change in body weight as covariates, the tensile strength, tensile stress, energy absorption capacity, and modulus of elasticity of the tendons were compared via multivariate analysis of covariance (MANCOVA). Laser treatment induced a significant increase in tensile strength (p = 0.03), tensile stress (p = 0.004, energy absorption capacity (p = 0.003), and modulus of elasticity (p ‹ 0.002) of the tendons. Specifically, the (mean ± SE) tensile strength was 80.62 ± 9.87 N for group one, 65.12 ± 11.34 N for group two, 87.50 ± 8.14 N for group three, and 56.43 ± 4.38 N for controls. Similarly, mean tensile stress values were 243.42 ± 21.25 N/cm², 191.54 ± 27.12 N/cm², 252.54 ± 24.86 N/cm², and 153.59 ± 12.57 N/cm², respectively. the corresponding energy absorption capacity values were 512.8 ± 91.0 mJ, 373.7 ±77.7 mJ, 580.7 ± 126.4 mJ, and 257.8 ± 47.9 mJ; while the moduli of elasticity were 475.45 ± 50.32, 391.22 ± 68.12, 487.84 ± 56.74, and 178.77 ± 32.92. Posthoc analyses showed that treatment with 0.5 J cm² GaAs laser significantly augments the healing strength, tensile stress, energy absorption capacity, and modulus of elasticity of rabbit calcaneal tendons especially during post-operative days 8-14 (t < 0.05). Although healing of rabbit tendons may differ from healing of human tendons, our findings suggest that similar beneficial effects may be obtained if human tendon ruptures are treated with 0.5 J/cm² GaAs Laser.

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Friend erythroleukaemia (FEL), and human myeloid HL60 cells were x-ray irradiated (3.0∼3.5 Gy), and then irradiated with low intensity laser irradiation (LILI) (660 nm, 12 mW, 5 kHz, 20 J/cm²). During the irradiation sessions the cell suspensions were maintained at 0∼4°C to minimize the normal processes of DNA repair. As a control for DNA repair, x-ray irradiated HL60 cells were incubated at 37°C (0∼15 minutes). Using the Comet Assay and a sensitive ELISA to quantify the percentage of single-stranded DNA, a significant reduction in DNA damage was demonstrated for the x-ray, laser irradiated cells, and also for the x-ray irradiated HL60 cells incubated for 5 or 15 minutes at 37°C, These results suggest that LILI facilitates the repair of x-ray induced DNA damage in cell suspensions held at 0∼4°C. LILI has no observable thermal effect on the medium surrounding cell suspensions. However, in view of these current results the possibility of an LILI mediated intracellular thermal effect should be considered.

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In rehabilitative training and treatment of patients with cerebral palsy, return and maintenance of good muscle tonicity and suppression of tonic muscle spasm is crucial. However, an effective method that is reliable, simple, painless and noninvasive has yet to be reported. In the present study, 150 cerebral palsy patients were treated on their limbs and trunk with infrared diode low reactive-level laser therapy (LLLT) (810 nm. 60 mW and 100 mW, continuous wave) , The treatment sites were those normally associated with conventional therapies such as nerve block or acupuncture, and where muscular hyperspasm was particularly evident. In the majority of the patients, spasm was successfully suppressed by LLLT, with the notable exception of those patients suffering from severe joint contracture. Compared with conventional methodology, laser therapy has proved to be a simple, reliable and noninvasive method which enabled painless suppression of spasm. Another of the advantages of LLLT is that multiple repeated application is possible on any site selected by the physician, with an almost unlimited choice of treatment sites. The effect of LLLT lasted from one to several hours in patients with severe spasticity. Although it may be argued that this variable length of effect is one of the limitations of LLLT, the authors feel that LLLT is particularly useful as a supplementary or adjunctive therapeutic modality to improve the overall efficacy of physical rehabilitation and functional training in children with cerebral palsy.

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A pilot study is presented on the transrectal application of helium neon (HeNe) laser energy (20 mW, c/w) via a specially-designed probe for the treatment of chronic prostatitis in a patient population of 235. Laser therapy was administered at doses of from 11.5∼14.4 J per 12∼15 minute daily session, with 8∼12 sessions required. Results were graded as: good (complaints relieved, ultrasound assessment, uroflowmetry and speed of micturation normal, and semen tests showed no inflammation); satisfactory (complaints reduced with partial improvements as above); and negative (little or no change). 70.2% were graded good, 20.9% as satisfactory and 21% as negative. The same system was also applied in the treatment of benign prostatic hypertrophy (BPH), in a patient population of 167 (69 BPH I and 98 BPH II). 12∼15 daily sessions of 20 min were required, with doses of 19.0∼20.8 J per session. With the same grading criteria as for the prostatitis group, results were good in 14.4%, satisfactory in 42.5% and negative in 43.1%. An additional group of 13 patients with prostatodynia received 5∼6 daily sessions of from 8 to 10 minutes, average dosage of 8.8 J/session. All 13 patients were graded good. All patients in the three groups had received conventional medical therapies, some over a period of years, but without effect. Although there was no attempt at double blinding in the present study, the author suggests that the positive results should encourage such a double blind trial to be set up, and that HeNe low level laser therapy (LLLT) applied transrectally is a valid alternative or adjunctive therapy for the minimally invasive and painless treatment of prostatic problems.

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The use of photodynamic therapy (PDT) using a photosensitizer such as haematoprphyrin and its derivatives (HpD) followed by application of low-intensity visible red laser energy in therapy for early-stage tumour destruction is well documented. The effect of the application of low intensity laser irradiation of a different wavelength, in low level laser therapy (LLLT) on the uptake or excretion of HpD into and from the tumour cells and tissue has not been investigated. The present study investigates the effect on tumour HpD uptake and excretion at from 30 minutes to 6 hours post HpD injection following the application of an infrared (890 nm) GaAs diode laser at two dosages (0.03067 J/cm² and 0.3067 J/cm²) immediately after; immediately and at 30 min after; 30 min before; and one day and 30 min before HpD injection compared with HpD injected but unirradiated control rats, all previously inoculated with Walker’s N256 sarcoma. The degree of fluorescence in the tumour was assessed using microspectrofluorometry, thus giving a direct indication of the amount of HpD compound present in the tumour. Previous reports on LLLT and its mechanisms suggested that there would be a higher absorption or uptake rate in the LLLT groups compared with controls. Contrary to these expectations, post HpD injection low intensity laser irradiated tumours showed slightly lower HpD uptake compared with the controls, and faster excretion, although the differences were not very statistically significant. Those tumours irradiated before HpD injection, on the other hand, showed dramatically and very highly statistically significantly decreased HpD uptake at 30 min postinjection, then a very slight tendency towards increased uptake until 3 hours postinjection, followed by increased excretion. In the LLLT groups there was no statistically significant difference between the two different doses. It is proposed that LLLT retards the uptake of HpD in the tumour cells by direct or indirect action on the microvasculature specifically on the permeability of the blood vessel walls and the celt membranes. The authors suggest that LLLT, at least at the wavelength and parameters used in the present study, should not be used as an adjunctive therapy before or after HpD injection for PDT in treatment of early-stage tumours.

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