Michael Heide

Technische Universität München, München, Bavaria, Germany

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Publications (5)7.72 Total impact

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    ABSTRACT: Patients suffering from uterine leiomyoma are often treated by hysterectomy or organ preserving myoma enucleation using electrosurgical, ultrasonic or radio-frequency techniques. Considerable thermal tissue damage leads to the development of scar formation which in the long term may result in complications during pregnancy. Therefore alternative techniques are required. After ethical approval, human uteri myomatosus were used to investigate the interaction of 1470 nm diode laser light (Medilas D MultiBeam; Dornier MedTech Laser GmbH, Weßling, Germany) during surgical procedures (laser mode, continuous wave; laser power, 5–30 W; fiber core diameter, 600 μm; cutting velocity, 3 mm/s). Macroscopic and microscopic evaluation was performed to improve understanding of tissue ablation and coagulation processes. Additionally laser-assisted The macroscopic visible coagulation rim was calculated to be at a maximum of ~550 μm in lateral direction (superficial width), and ~300 μm in axial plane (sagittal depth). Microscopic examination of hematoxylin and eosin stained sagittal tissue slices showed a largest ablation depth of 279.1±186.8 μm and a maximum irreversibly damaged remaining tissue depth of 628.7±354.3 μm when a laser power of 30 W was applied. The ratio of the remaining tissue and ablation depth indicates that increased applied laser power results in a faster ablation than coagulation into the depth. Hands-on Sufficient and effective ablation and coagulation of uterus myomatosus tissue and the
    No preview · Article · Jan 2016
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    ABSTRACT: In azoospermic patients, spermatozoa are routinely obtained by testicular sperm extraction (TESE). However, success rates of this technique are moderate, because the site of excision of testicular tissue is determined arbitrarily. Therefore the aim of this study was to establish probe-based laser endomicroscopy (pCLE) a noval biomedical imaging technique, which provides the opportunity of non-invasive, real-time visualisation of tissue at histological resolution. Using pCLE we clearly visualized longitudinal and horizontal views of the tubuli seminiferi contorti and localized vital spermatozoa. Obtained images and real-time videos were subsequently compared with confocal laser scanning microscopy (CLSM) of spermatozoa and tissues, respectively. Comparative visualization of single native Confocal laser scanning microscopy (CLSM, left) and probe-based laser endomicroscopy (pCLE, right) using Pro Flex(TM) UltraMini O after staining with acriflavine.
    No preview · Article · Jul 2014 · Journal of Biophotonics
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    ABSTRACT: Endovenous laser therapy (ELT) was introduced in clinical practice as a therapy for incompetent veins about ten years ago. One characteristic of ELT is the broad spectrum of different treatment protocols by means of a variety of laser systems as well as manifold application forms and dosimetry concepts which are under investigations.
    No preview · Conference Paper · Jun 2014
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    ABSTRACT: Objective: Provide preclinical data on the feasibility of 5-aminolevulinic acid (5-ALA) -based photodetection (PD) and Photodynamic Therapy (PDT) of early childhood tumors. Methods: Hepatoblastoma (HuH6), neuroblastoma (MHH-NB11) and N1-fibroblast cell lines were tested for their relative capacities to synthesize Protoporphyrin IX (PpIX) from 5-ALA and for their susceptibility to PDT in vitro. HuH6-cells were also inoculated in the peritoneum of rats. The pharmacokinetics of porphyrin accumulation was measured in 9 rats by laparoscopic spectroscopy. 5-ALA was applied by i.p. injection of 500 mg/kg bw. In another 21 animals, tumors (n=20), liver (n=5) and peritoneum (n=4) were treated by PDT laparoscopically. 48 h after irradiation, animals were again incubated with 5-ALA and then sacrificed and tissues were removed for further investigation. Results: Both tumor cell lines showed higher levels of porphyrin fluorescence than the fibroblasts. Cell viability testing proved the HuH6 cells to be most susceptible to PDT. Pharmacokinetic measurements of PpIX in xenografted tumors showed a peak at 80-200 min after i.p. injection of 5-ALA. Irradiation resulted in pronounced photobleaching at all irradiated sites and necrosis of tumor and liver tissue, whereas peritoneum appeared to remain unaffected. Necrosis induced by PDT could be seen in fluorescence microscopy due to the lack of porphyrin synthesis in necrotic tissue after the re-incubation with 5-ALA.
    No preview · Article · May 2011 · Proceedings of SPIE - The International Society for Optical Engineering
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    ABSTRACT: Aminolevulinic acid (ALA)-mediated photodynamic therapy (PDT) may represent a treatment option for malignant brain tumors. We used a three-dimensional cell culture system, the C6 glioma spheroid model, to study acute effects of PDT and how they might be influenced by treatment conditions. Spheroids were incubated for 4 h in 100 microg/ml ALA in 5% CO(2) in room air or 95% O(2) with subsequent irradiation using a diode laser (lambda = 635 nm, 40 mW/cm(2), total fluence 25 J/cm(2)). Control groups were "laser only", "ALA only", and "no drug no light". Annexin V-FITC, a marker used for detection of apoptosis, propidium iodide (PI), a marker for necrotic cells and H 33342, a chromatin stain, were used for morphological characterization of PDT effects by confocal laser scanning and fluorescence microscopy. Hematoxylin-eosin staining and TdT-FragEL (TUNEL) assay were used on cryosections. Growth kinetics were followed for 8 days after PDT. PDT after incubation in 5% CO(2) provided incomplete cell death and growth delay in spheroids of >350 microm diameter. However, complete cell death and growth arrest occurred in smaller spheroids (<350 microm). Incubation in 95% O(2) with subsequent PDT resulted in complete cell death and growth arrest regardless of spheroid size. In incompletely damaged spheroids viable cells were restricted to spheroid centers. The rate of cell death in all control groups was negligible. Cell death was accompanied by annexin/PI costaining, but there was also evidence for annexin V-FITC staining without PI uptake. PDT of experimental glioma results in rapid and significant cell death that could be verified as acute necrosis immediately after irradiation. This effect depended on O(2) concentration and spheroid size.
    No preview · Article · Mar 2007 · Journal of Neuro-Oncology