Raymond J. Lanzafame

Effects of photostimulation on wound healing in diabetic mice

Low‐level laser irradiation at certain fluences and wavelengths can enhance the release of growth factors from fibroblasts and stimulate cell proliferation in vitro. We evaluated whether low‐level laser irradiation can improve wound healing in diabetes mellitus.

In vitro effects of low-level laser irradiation at 660 nm on peripheral blood lymphocytes.

The effects of low‐level laser light irradiation are still highly contested, and the mechanisms of its action still unclear. This study was conducted to test the effects of low‐level laser irradiation at 660 nm on human lymphocytes and to investigate the possible mechanisms by which these effects are produced.

Development of a Simple, Noninvasive, Clinically Relevant Model of Pressure Ulcers in the Mouse

The formation of pressure ulcers and other skin wounds is considered to be a multifactorial process. Cycles of ischemia–reperfusion have been considered to be significant contributing factors in the pathogenesis of pressure ulcers. This study reports the development of a reproducible murine model of ischemia–reperfusion injury by the external application of magnets. Mice were sedated with 50% CO2:50% O2 for 50–60 s. Dorsal hair was shaved and the area cleaned. The skin was gently pulled and placed between two round ceramic magnetic plates (5 × 12 mm diameter, 2.4 g weight, 1000 G magnetic force). The resultant “pinch” procedure was designed to leave a 5-mm skin bridge between the magnets, creating 50 mm Hg pressure between the plates. Three 12-h ischemia–reperfusion cycles were employed to cause pressure ulcer formation. Animals tolerated the procedure well. They returned to normal activity a few minutes after magnet placement. The lesions reached their maximum at 10 days postinjury. Full-thickness skin loss with damage and necrosis of subcutaneous tissue (ulcer stage 3) was observed in all cases, reaching a mean stage score of 3.6 ± 0.6 of based on a 0–5 scale for extent of injury by visual assessment. Thus, an inexpensive, reproducible murine pressure ulcer model was developed, which results in graded injury without long-term immobilization of the animals. This method will facilitate the development of new prevention and management strategies.

Photo-irradiation improved functional preservation of the isolated rat heart

Photo‐irradiation causes a variety of effects in different cells and tissues. We hypothesized that photo‐irradiation may improve cardiac preservation based on these observations.

Improvement of host response to sepsis by photobiomodulation

Late sepsis causes immunosuppression and is associated with energy depletion in lymphocytes. Adjuvant treatment with ATP‐MgCL2 appears to improve cellular energetics and decrease mortality. Laser irradiation can promote cell proliferation and increase cellular ATP synthesis, which may improve the host immune response in sepsis. The purpose of this study was to determine whether laser irradiation (LI) has a stimulatory effect on the immune response in sepsis using an animal model.

The Effect of Molecular Weight and Gel Preparation on Humoral Adjuvancy of Silicone Oils and Silicone Gels

Silicone gels from commercial breast implants have been shown previously by our laboratory to be potent humoral adjuvants, while the low molecular size 20 centistoke (cs) silicone oil (M.W. 1900) possesses no measurable adjuvant properties. It became necessary to shear the silicone gel during our previous experiments in order to facilitate injection through a syringe and needle, it is conceivable that shearing may reduce the molecular weight of the silicone gel used. This investigation was undertaken to determine whether humoral adjuvancy of silicone oils is dependent on molecular weight and whether the method of shearing the silicone gel affects its adjuvancy. Four Dow Corning 360 Medical silicone oils (100 cs, M.W. approximately 5,000; 350 cs, M.W. approximately 10,000; 1000 cs, M.W. approximately 16,500 and 12,500 cs, M.W. approximately 60,000) and Dow Corning octamethylcyclotetrasiloxane (D4, M.W. 296) were tested for their humoral adjuvancy by immunizing 64 Sprague Dawley rats with 50 micrograms of bovine serum albumin (BSA) mixed with each oil. The rats were periodically bled and the sera were analyzed for anti-BSA antibodies by ELISA. In a separate experiment, three silicone gel preparations with reproducible characteristics were prepared by using a tissue homogenizer and varying the applied shear force. Each of these preparations was tested for its humoral adjuvancy as previously described for silicone oils. Rats immunized with BSA mixed with the highest molecular size silicone oil tested (M.W. approximately 60,000) showed a significant increase in anti-BSA antibodies as compared to the lower molecular size oils. The three silicone gel preparations showed no difference in their adjuvancy effect. Thus, the humoral adjuvancy of silicone oil appears to be dependent on molecular weight. Differential shearing of the silicone gel does not alter its humoral adjuvancy.

The effect of silicone-gel on the immune response.

Silicone materials have been used in medical applications for at least 30 years. Despite this long history of use the question whether silicones can mediate an immunological reaction that may be detrimental to the host remains unanswered. Most studies on the biocompatability of silicones conclude that silicones are chemically stable compounds, which however are often capable of eliciting a benign chronic inflammatory response. Recently, our laboratory has conducted a series of animal experiments aimed at determining the immunological adjuvancy potential of silicone-gel taken from commercial breast implants. Our previous studies have indicated that silicone-gel is a potent humoral (antibody) adjuvant. Our present studies have found that silicone-gel is capable of eliciting auto-antibodies to rat thyroglobulin and bovine collagen II. However this immune response did not produce any histological evidence of thyroiditis or arthritis. Theories to explain why silicone-gel behaves as an adjuvant are discussed along with discussion of the hypothesis on the desirability of replacing silicone-gel with a more hydrophilic material in bioimplants.

Acute tensile strength analysis of collagen solder for mesh fixation to the peritoneal surface

BackgroundIn this study, we assessed the feasibility of laser-assisted tissue welding as a means of fixing mesh prostheses to the peritoneum. We then tested the initial tensile strength of the bonds.MethodsFresh porcine peritoneal coupons were lap-joint bonded with laser-activated solder. Anesthetized New Zealand white rabbits and Yorkshire pigs also underwent laparotomy. Vicryl mesh (2.0 × 1.0 cm) was attached to the peritoneum using a laser system (1.43 μ, 2.5 W, 60°C), solder formulations and configurations, and a 1 cm2 bond area. Control segments were affixed with 4.8-mm staples. After the animals were killed, the segments were excised en bloc. Tensile strength assessment was conducted by measuring peak force breaking strength.ResultsThe strength of the solder bonds were similar in all groups (range, 261.5 ± 170.3-465.3 ± 288.2 g/cm2) and were not statistically different from the controls (215.8 ± 117.8 g/cm2).ConclusionsThese values are similar to the 200-500 g/cm2 acute strengths reported for sutured or stapled peritoneal closure. Mesh fixation by solder is feasible, and further development of this technology is warranted.

Effect of argon laser and photofrin II on murine neuroblastoma cells

Laser-induced fluorescence (LIF) of photosensitizers is used to detect cancer. The effect of argon laser light with an average irradiance of 31 mW cm-2 and Photofrin II (Dihematoporphyrin ether, DHE) at concentrations of 1.0 and 5.0 micrograms ml-1 on C1300 murine neuroblastoma cells (MNB, NB41A3) in vitro was investigated. Growth curves and cell viability (trypan blue dye exclusion) were determined at 1, 24, 96, and 144 hr post-irradiation. Light doses of 1.8 and 9.0 J cm-2 combined with 5.0 micrograms DHE ml-1 decreased both cell numbers and viability, immediately and up to 144 hr postirradiation. Argon laser light alone at a fluence of 9.0 J cm-2 caused reversible injury to the cells. This in vitro study shows that both low energy argon laser light and low dose DHE are cytocidal to C1300 MNB cells. LIF promises to aid in the detection and destruction of neuroblastoma. Surgeons should be aware that tissue irreversible damage is likely to occur when performing LIF detection of neuroblastoma. The doses of laser light and of Photofrin II found to be toxic to neuroblastoma cells in culture may provide guidelines for photodynamic therapy ablation of neuroblastoma clinically.

Laser/Light Applications in General Surgery

Lasers and light source technologies have been applied to a wide variety of open and laparoscopic procedures in general surgery and other disciplines.