Leonardo Longo

Light Supports Neurite Outgrowth of Human Neural Progenitor Cells In Vitro : The Role of P2Y Receptors

The purpose of this study was to compare the effects of growth factors and 810-nm-wavelength light on the differentiation of normal human neural progenitor cells (NHNPCs) in vitro. Although growth factors are routinely used to study neural stem and progenitor cells in vitro, to date, light has not been used as a replacement for growth factors. This study demonstrates that NHNPCs are not only capable of being sustained by light in the absence of growth factors, but that they are also able to differentiate normally as assessed by neurite formation. The NHNPCs had an up-regulation in the expression of endogenous fibroblast growth factor-2, brain derived neurotrophic factor, and nerve growth factor in response to the light. Suramin, a nonselective P2 receptor antagonist, significantly decreased neurite outgrowth, and P2Y2 and P2Y11 receptors were found to be expressed by the NHNPCs by immunolabeling. Based on these findings, the mechanism by which light supports the NHNPC differentiation is hypothesized to be due to increases in adenosine triphosphate acting via P2Y receptors.

Two-year follow-up results of copper bromide laser treatment of striae.

OBJECTIVE The aim of our study was to follow-up 15 patients with stretch marks treated positively with the CuBr laser (577-511 nm) in 1998-99 and followed-up for 2 years. MATERIALS AND METHODS The patients were Italian women, young to middle age (average 30 years old), with skin coloration classified as Fitzpatrick II-III. Biopsies were taken on some patients before the treatment and 1 month after the first treatment. Double-blind histological, histochemical and photographic evaluation was performed. Results obtained as well as to the contradictory effects reported elsewhere in the literature were compared. RESULTS On average, the results were positive and there were some pathogenic considerations that justified the use of laser.

In vitro cell compatibility study of rose bengal–chitosan adhesives

Photochemical tissue bonding (PTB) using rose bengal (RB) in conjunction with light is an alternative technique to repair tissue without suturing. It was recently demonstrated that laser‐irradiated chitosan films, incorporating RB, bonded firmly to calf intestine in vitro. It is thus required to investigate the possible cytotoxic effects of the RB–chitosan adhesive on cells before testing its application to in vivo models.

Fabrication and application of rose bengal-chitosan films in laser tissue repair.

Photochemical tissue bonding (PTB) is a sutureless technique for tissue repair, which is achieved by applying a solution of rose bengal (RB) between two tissue edges(1,2). These are then irradiated by a laser that is selectively absorbed by the RB. The resulting photochemical reactions supposedly crosslink the collagen fibers in the tissue with minimal heat production(3). In this report, RB has been incorporated in thin chitosan films to fabricate a novel tissue adhesive that is laser-activated. Adhesive films, based on chitosan and containing ~0.1 wt% RB, are fabricated and bonded to calf intestine and rat tibial nerves by a solid state laser (λ=532 nm, Fluence~110 J/cm(2), spot size~0.5 cm). A single-column tensiometer, interfaced with a personal computer, is used to test the bonding strength. The RB-chitosan adhesive bonds firmly to the intestine with a strength of 15 ± 6 kPa, (n=30). The adhesion strength drops to 2 ± 2 kPa (n=30) when the laser is not applied to the adhesive. The anastomosis of tibial nerves can be also completed without the use of sutures. A novel chitosan adhesive has been fabricated that bonds photochemically to tissue and does not require sutures.

The Combination of Light and Stem Cell Therapies: A Novel Approach in Regenerative Medicine

Light therapy commonly referred to as low level laser therapy can alter cellular functions and clinical conditions. Some of the commonly reported in vitro and in vivo effects of light therapy include cellular proliferation, alterations in the inflammatory response to injury, and increases in mitochondrial respiration and adenosine triphosphate synthesis. Based on the known effects of light on cells and tissues in general and on reports in the last 5 years on the interaction of light with stem cells, evidence is mounting indicating that light therapy could greatly benefit stem cell regenerative medicine. Experiments on a variety of harvested adult stem cells demonstrate that light therapy enhances differentiation and proliferation of the cells and alters the expression of growth factors in a number of different types of adult stem cells and progenitors in vitro. It also has the potential to attenuate cytotoxic effects of drugs used to purge harvested autologous stem cells and to increase survival of transplanted cells.

New postlaser resurfacing medical treatment

Today, laser resurfacing technique is codified. The purpose of our study is to reduce the post-intervention discomfort and the clinical signs. We tested a combination of pharmacological substances, applied as spray lotion and gel during and immediately after the intervention and the days after. We used this substances after laser resurfacing done with CO2 laser, Er:YAG laser and both. We noted a reduction statistically significant of the signs up described, with reduction of the recovery time. It is our opinion that this medical treatment must be done always, during and post laser resurfacing treatment.

Chitosan Adhesive Films for Photochemical Tissue Bonding

Photochemical tissue bonding (PTB) is a promising sutureless technique for tissue repair. PTB is often achieved by applying a solution of rose bengal (RB) between two tissue edges, which are irradiated by a green laser to crosslink collagen fibers with minimal heat production. In this study, RB has been incorporated in chitosan films to create a novel tissue adhesive that is laser‐activated. Materials and Methods. Adhesive films, based on chitosan and containing ∼0.1wt% RB were manufactured and bonded to calf intestine by a solid state laser (wavelength = 532 nm, Fluence ∼110 J/cm2, spot size ∼5 mm). A single‐column tensiometer, interfaced with a personal computer, tested the bonding strength. K‐type thermocouples recorded the temperature (T) at the adhesive‐tissue interface during laser irradiation. Human fibroblasts were also seeded on the adhesive and cultured for 48 hours to assess cell growth. Results and Conclusion. The RB‐chitosan adhesive bonded firmly to the intestine (15±2 kPa, n = 31). The adhe...

Is there a best wavelength for laser treatment of telangiectases

Our purpose is to establish the best wavelength and dosage of laser therapy in the treatment of the telangiectases..

Genetic Tolerance to Rose Bengal Photodynamic Therapy and Antifungal Clinical Application for Onychomycosis

Photodynamic therapy (PDT) with rose bengal has seen increasing use in clinical applications and has shown effective antifungal capacity in vitro. However, there is limited understanding of the effects of this emerging therapy at a genetic level. A rose bengal PDT screen using a green laser (λ = 532 nm) on the entire non‐essential gene library of the model organism, Saccharomyces cerevisiae, and a subsequent pilot patient study (n = 6 patients) in the treatment of onychomycosis caused by Trichophyton rubrum is reported. Of the 4800 yeast strains screened, 482 sensitive and 175 resistant strains are identified. The key biochemical pathways found to be affected included ergosterol biosynthesis, vacuolar acidification, and purine/S‐adenosyl‐l‐methionine biosynthesis. The implications of these findings inform the clinical application of an optimized rose bengal PDT protocol involving nail treatment with a rose bengal solution (140 µm) and green light irradiation (fluence ≈763 J cm−2). All patients achieved complete cure within three to five treatment sessions in the absence of pain or other side effects. The outcome of the genetic screen may thus inform the development of more efficient clinical treatments using rose bengal PDT, as demonstrated in the successful treatment of onychomycosis.

ECM‐Chitosan Bandage for Tissue Repair

Extracellular matrices (ECMs) are currently applied in reconstructive surgery to enhance wound healing and tissue remodelling. Sutures and staples are usually employed to stabilize ECM on tissue although they may damage the matrix structure. In this investigation, a novel biocompatible bandage was developed to implant ECM on tissue without sutures. An adhesive film, based on chitosan, was integrated with small intestine submucosa (SIS) in a single bandage strip. This bandage was bonded to sheep small intestine upon laser irradiation of the chitosan film (P = 0.12 W, Fluence = 46±1 J/cm2) to assess tissue adhesion strength. Thermocouples were used to estimate temperatures under SIS during laser irradiation. The bandage successfully bonded to intestine achieving a shear stress of 9.6±1.6 kPa(n = 15). During laser irradiation, the temperature increased modestly to 31±2 0C(n = 14) beneath the ECM portion of the bandage. The SIS‐chitosan bandage bonded effectively to tissue without sutures and preserved the EC...