6 research outputs found
Atominterferometrie im Zeitbereich
[no abstract
Photodynamic therapy of murine non-melanoma skin carcinomas with diode laser after topical application of aluminum phthalocyanine chloride
The aim of this work is to study pharmacokinetics and photodynamic
efficiency of aluminium phthalocyanine chloride (AICIPc) in
dimethylsulfoxide/Tween 80/water solution, after topical application on
hairless mice bearing non-melanoma skin carcinomas. The concentration of
photosensitizer in normal skin and tumor biopsies 1-6 hours after
application was assessed by fluorescence spectroscopy of chemical
extractions. The concentration of photosensitizer was 40 times higher in
tumor than in normal skin even 1 h after application.
For photodynamic therapy (PDT) AlClPc was excited by a diode laser
emitting at 670 nm, 1 h after application. Seven different combinations
of therapeutic parameters were chosen. The efficiency was assessed as
the percentage of complete tumor remission, the tumor growth retardation
and the cosmetic outcomes. The highest complete remission 60% was
achieved with the combination of 75 mW/cm(2) with 150 J/cm(2). No
recurrence rate was observed in any treatment parameters group and the
cosmetic outcome in all completely treated tumors was excellent. The
results show that the effectiveness of PDT is highly dependent on
fluence rate. In addition, they are promising for further investigation
of this PDT scheme in preclinical studies mainly in non-melanoma skin
carcinomas up to 7mm
Pharmacokinetic study of a systemically administered novel liposomal Temoporfin formulation in an animal tumor model
Meso-tetra(hydroxyphenyl)chlorin (mTHPC) (international generic name Temoporfin) is a potent photosensitizer used for photodynamic therapy (PDT). In this study the pharmacokinetics of a systemically administered novel lipid formulation of Temoporfin in a murine tumor model has been investigated. Fluorescence spectroscopy measurements were performed at several time intervals following drug administration, yielding information on the Temoporfin concentration within excised internal organs as a function of time after injection. Both point-monitoring and imaging setups were used. The acquired fluorescence data were correlated to the concentration of Temoporfin obtained with High Performance Liquid Chromatography (HPLC). There was a significant correlation between the fluorescence methods and HPLC for most organs investigated. The pharmacokinetics of this new liposomal formulation of Temoporfin exhibited a rather flat temporal profile in the time interval 2-8 hours in this study
In Vitro Feasibility Analysis of a New Sutureless Wound-Closure System Based on a Temperature-Regulated Laser and a Transparent Collagen Membrane for Laser Tissue Soldering (LTS)
For the post-surgical treatment of oral wounds and mucosal defects beyond a certain size, the gold standard is still an autologous skin or mucosal graft in combination with complex suturing techniques. A variety of techniques and biomaterials has been developed for sutureless wound closure including different tissue glues or collagen patches. However, no wound covering that enables for sutureless fixation has yet been introduced. Thus, a new system was developed that allows for sutureless wound covering including a transparent collagen membrane, which can be attached to the mucosa using a specially modified 2λ laser beam with integrated temperature sensors and serum albumin as bio-adhesive. The sutureless wound closure system was tested for its applicability and its cytocompatibility by an established in vitro model in the present study. The feasibility of the laser system was tested ex vivo on a porcine palate. The in vitro cytocompatibility tests excluded the potential release of toxic substances from the laser-irradiated collagen membrane and the bio-adhesive. The results of the ex vivo feasibility study using a porcine palate revealed satisfactory mean tensile strength of 1.2–1.5 N for the bonding of the membrane to the tissue fixed with laser of 980 nm. The results suggest that our newly developed laser-assisted wound closure system is a feasible approach and could be a first step on the way towards a laser based sutureless clinical application in tissue repair and oral surgery
Fluorescence monitoring of a topically applied liposomal temoporfin formulation and photodynamic therapy of nonpigmented skin malignancies.
Meso-tetra(hydroxyphenyl)chlorin (mTHPC) (INN: Temoporfin) is a potent photodynamically active substance in clinical use today. Usually, the substance is given systemically and a known drawback with this administration route is a prolonged skin light sensitization. For the first time to our knowledge, a liposomal Temoporfin gel formulation for topical application was studied in connection with photodynamic therapy (PDT) of nonpigmented skin malignancies in humans. Intervals of 4 hr between drug administration and light irradiation were used. Sensitizer distribution within tumor and surrounding normal skin was investigated by means of point monitoring and imaging fluorescence spectroscopy before, during, and after PDT, showing high tumor selectivity. Furthermore, the bleaching of Temoporfin was studied during the PDT procedure by monitoring the fluorescence following excitation by using a therapeutic light. A 30−35% light-induced photometabolization was shown. No pain occurred during or after treatment. It was also observed that the treated area did not show any swollen tissue or reddening, as is often seen in PDT using topical δ-aminolevulinic acid. On controlling the patients one week after treatment, healing progress was observed in several patients and no complications were registered