In Vitro Photodynamic Therapy with Chlorin e6 Leads to Apoptosis of Human Vascular Smooth Muscle Cells

Percutaneous coronary intervention has become the most common and widely implemented method of heart revascularization. However, the development of restenosis remains the major limitation of this method. Photodynamic therapy (PDT) recently emerged as a new and promising method for the prevention of arterial restenosis. Here the efficacy of chlorin e6 in PDT was investigated in vitro using human vascular smooth muscle cells (TG/HA-VSMCs) as one of the cell types crucial in the development of restenosis. PDT-induced cell death was studied on many levels, including annexin V staining, measurement of the generation reactive oxygen species (ROS) and caspase-3 activity, and assessment of changes in mitochondrial membrane potential and fragmentation of DNA. Photosensitization of TG/HA-VSMCs with a 170 μM of chlorin e6 and subsequent illumination with the light of a 672-nm diode laser (2 J/cm2) resulted in the generation of ROS, a decrease in cell membrane polarization, caspase-3 activation, as well as DNA fragmentation. Interestingly, the latter two apoptotic events could not be observed in photosensitized and illuminated NIH3T3 fibroblasts, suggesting different outcomes of the model of PDT in various types of cells. The results obtained with human VSMCs show that chlorin e6 may be useful in the PDT of aerial restenosis, but its efficacy still needs to be established in an animal model

Hg 5d and 6s: Multichannel quantum-defect analysis of experimental data

Schäfers F, Heckenkamp C, Müller M, Radojevic V, Heinzmann U. Hg 5d and 6s: Multichannel quantum-defect analysis of experimental data. Physical Review, A: Atomic, Molecular and Optical Physics. 1990;42(5):2603-2613.Experimental spin-polarization data for the Hg 6s Cooper minimum and dipole-transition amplitudes and phase-shift differences for photoionization of the Hg 5d and 6s shells (eight channels) in the photon-energy region from the 2D3/2 threshold up to 35 eV (kinetic energies from 0 to 20 eV) are presented and compared with new relativistic random-phase approximation calculations. The data were evaluated from an experimental data set, quantum mechanically complete, consisting of cross-section and photoelectron spin-polarization data. For the 5d subshells the results show strong interchannel coupling between the outgoing p and f continuum channels. The results for Hg 6s could be used for an independent determination of the photoelectron angular distribution parameter [Beta] in the Cooper-minimum region. This region is shown to be perturbed by numerous two-electron excitations, which might be a possible explanation for the controversy on its location

Cancer therapy and cardiotoxicity: The need of serial Doppler echocardiography

Cancer therapy has shown terrific progress leading to important reduction of morbidity and mortality of several kinds of cancer. The therapeutic management of oncologic patients includes combinations of drugs, radiation therapy and surgery. Many of these therapies produce adverse cardiovascular complications which may negatively affect both the quality of life and the prognosis. For several years the most common noninvasive method of monitoring cardiotoxicity has been represented by radionuclide ventriculography while other tests as effort EKG and stress myocardial perfusion imaging may detect ischemic complications, and 24-hour Holter monitoring unmask suspected arrhythmias. Also biomarkers such as troponine I and T and B-type natriuretic peptide may be useful for early detection of cardiotoxicity. Today, the widely used non-invasive method of monitoring cardiotoxicity of cancer therapy is, however, represented by Doppler-echocardiography which allows to identify the main forms of cardiac complications of cancer therapy: left ventricular (systolic and diastolic) dysfunction, valve heart disease, pericarditis and pericardial effusion, carotid artery lesions. Advanced ultrasound tools, as Integrated Backscatter and Tissue Doppler, but also simple ultrasound detection of "lung comet" on the anterior and lateral chest can be helpful for early, subclinical diagnosis of cardiac involvement. Serial Doppler echocardiographic evaluation has to be encouraged in the oncologic patients, before, during and even late after therapy completion. This is crucial when using anthracyclines, which have early but, most importantly, late, cumulative cardiac toxicity. The echocardiographic monitoring appears even indispensable after radiation therapy, whose detrimental effects may appear several years after the end of irradiation

A rotatable electron spectrometer system for spin- and angle-resolved photoemission experiments with circularly polarized synchrotron radiation

Heckenkamp C, Eyers A, Schäfers F, Schönhense G, Heinzmann U. A rotatable electron spectrometer system for spin- and angle-resolved photoemission experiments with circularly polarized synchrotron radiation. Nuclear Instruments and Methods in Physics Research A: Accelerators, Spectrometers, Detectors and Associated Equipment. 1986;246(1-3):500-503.An electron-optical system is described which has been especially designed for spin- and angle-resolved photoelectron spectroscopy with circularly polarized synchrotron radiation. One hv- and one uhv-type of this system (for studies at atoms/molecules and solids/adsorbates, respectively) are in operation at the storage ring BESSY. The system employs, thus, a light source and an electron spin detector (high energy Mott detector) both fixed in space. This is realized by a rotatable electron spectrometer and a 90° deflector by which the electron beam is directed along the axis of rotation of the spectrometer, independent of the emission angle chosen

A high flux normal incidence monochromator for circularly polarized synchrotron radiation

Eyers A, Heckenkamp C, Schäfers F, Schönhense G, Heinzmann U. A high flux normal incidence monochromator for circularly polarized synchrotron radiation. Nuclear Instruments and Methods in Physics Research. 1983;208(1-3):303-305.Design and performance of a 6.3 m normal incidence UHV-monochromator (see fig. 1) of the Gillieson type for synchrotron radiation are described. The monochromator will be used for simultaneously spin polarization and emission angle-resolved photoelectron spectroscopy; it combines a high photon flux and a high degree of circular polarization of the monochromatized radiation with a moderate resolution

Energy dependence of the electron spin polarisation parameters for Hg 5d photoionisation with circularly polarised light

Schäfers F, Heckenkamp C, Schönhense G, Heinzmann U. Energy dependence of the electron spin polarisation parameters for Hg 5d photoionisation with circularly polarised light. Journal of Physics B: Atomic, Molecular and Optical Physics. 1988;21(5):769-774.Circularly polarised VUV radiation from the storage ring BESSY was used to measure all three spin polarisation parameters of photoelectrons from the Hg 5d shell in the photon energy range from threshold to approximately 35 eV. The experimental results are compared with theoretical calculations in the relativistic and non-relativistic random-phase-approximation scheme (RRPA and RPAE respectively) and Dirac-Slater (DS) calculations. A discussion of the influence of relativistic and potential barrier effects on the experimental data is given

A laser-generated plasma as a source of VUV continuum radiation for photoelectronic spectroscopy

Heckenkamp C, Heinzmann U, Schönhense G, Burgess DD, Thorne AP, Wheaton JEG. A laser-generated plasma as a source of VUV continuum radiation for photoelectronic spectroscopy. Journal of Physics D: Applied Physics. 1981;14(12):L203-L206.The feasibility of using laser-generated plasmas as VUV continuum sources for photoelectron spectroscopy has been demonstrated by measuring the spectral intensity distribution of the VUV continuum in the wavelength region from 79 to 43 nm by energy analysis of the photoelectrons ejected from argon atoms. The maximum photon flux obtained after reflection at a gold-coated spherical mirror was of the order of 10(11) photons nm(-1) per pulse at 50 nm for a laser energy of 830 mJ. The results show a shift of the emission maximum to lower wavelengths with increasing laser energy