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Nd-YAG Laser (nd-yag + laser)
Selected AbstractsBarrett's esophagus: combined treatment using argon plasma coagulation and laparoscopic antireflux surgeryDISEASES OF THE ESOPHAGUS, Issue 4 2003M. Pagani SUMMARY, The treatment of Barrett's esophagus is still controversial. Actually, the only method to prevent the development to cancer is endoscopic surveillance, which ensures good results in terms of long-term survival. An ideal treatment capable of destroying columnar metaplasia, followed by squamous epithelium regeneration could potentially result in a decrease of the incidence of adenocarcinoma. Recently most ablative techniques were used, such as photodynamic therapy, ablation therapy with Nd-YAG laser or argon plasma coagulation and endoscopic mucosal resection. We started a prospective study in January 1998, enrolling 94 patients affected by Barrett's esophagus and candidates for antireflux repair in order to assess the effectiveness and the results of endoscopic coagulation with argon plasma combined with surgery in the treatment of uncomplicated Barrett's esophagus. All patients underwent endoscopic treatment with argon plasma; we observed complete response in 68 patients (72.34%), 27 of them (39.7%) underwent antireflux surgery and the other 41 continued medical therapy. Post-operatively 19 patients (70%) underwent regular surveillance endoscopies and in two cases metaplasia recurred. The final objective of these combined treatments should be the complete eradication of metaplastic mucosa. Our experience was that argon plasma coagulation combined with antireflux surgery or proton pump inhibitor therapy gave satisfactory results, even if follow-up is too short to evaluate the potential evolution of metaplasia to cancer. For this reason, we recommend that this technique should be done only in specialized centres and that these patients continue their endoscopic surveillance program. [source] Impairment of cytoskeleton-dependent vesicle and organelle translocation in green algae: combined use of a microfocused infrared laser as microbeam and optical tweezersJOURNAL OF MICROSCOPY, Issue 2 2002A. Holzinger Summary A Nd-YAG laser at 1064 nm is used as optical tweezers to move intracellular objects and a laser microbeam to cause impairment of cytoskeleton tracks and influence intracellular motions in desmidiaceaen green algae. Naturally occurring migrations of large nuclei are inhibited in Micrasterias denticulata and Pleurenterium tumidum when the responsible microtubules are targeted with a laser microbeam generating 180 mW power in the focal plane. Impairment of the microtubule tracks appears to be irreversible, as the nucleus cannot pass the former irradiated area in Pleurenterium or remains abnormally dislocated in Micrasterias. The actin filament-dependent movement of secretory vesicles and smaller particles can be manipulated by the same IR-laser at 90 mW when functioning as optical tweezers. In Closterium lunula particles are displaced from their cytoplasmic tracks for up to 10 µm but return to their tracks immediately after removing the light pressure gained by the optical tweezers. The cytoplasmic tracks consist of actin filament cables running parallel to the longitudinal axis of Closterium cells as depicted by Alexa phalloidin staining and confocal laser scanning microscopy. Dynamics and extensibility of the cytoplasmic strands connecting particles to the tracks are also demonstrated in the area of large vacuoles which are surrounded by actin filament bundles. In Micrasterias trapping of secretory vesicles by the optical tweezers causes irreversible malformations of the cell shape. The vesicle accumulation itself dissipates within 30 s after removing the optical tweezers, also indicating reversibility of the effects induced, in the case of actin filament-mediated processes. [source] The design of single particle laser mass spectrometers,MASS SPECTROMETRY REVIEWS, Issue 2 2007Daniel M. MurphyArticle first published online: 16 OCT 200 Abstract This review explores some of the design choices made with single particle mass spectrometers. Different instruments have used various configurations of inlets, particle sizing techniques, ionization lasers, mass spectrometers, and other components. Systematic bias against non-spherical particles probably exceeds a factor of 2 for all instruments. An ionization laser tradeoff is the relatively poor beam quality and reliability of an excimer laser versus the longer wavelengths and slower response time of an Nd-YAG laser. Single particle instruments can make special demands on the speed and dynamic range of the mass spectrometers. This review explains some of the choices made for instruments that were developed for different types of measurements in the atmosphere. Some practical design notes are also given from the author's experience with each section of the instrument. Published 2006 Wiley Periodicals, Inc., Mass Spec Rev 26:150,165, 2007 [source] Two-photon Excitation Induced Fluorescence of a Trifluorophore-labeled DNA,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2005Steffen Jockusch ABSTRACT Two-photon excitation of a trifluorophore (6-carboxyfluorescein, N, N, N,, N, -tetramethyl-6-carboxyrhodamine and cyamine-5 monofunctional dye) labeled DNA, which has a scaffold of 26 nucleotides, was achieved using focused laser light of a Q-switched Nd-YAG laser (1064 nm). The observed fluorescence signature (emission ratio from the three fluorophores) of the labeled DNA after two-photon excitation is very different from the fluorescence signatures produced by one-photon excitation at different wavelenght. The additional fluorescence signatures produced by two-photon excitation of the fluorescent oligonucleotides will facilitate their use as combinatorial fluorescence energy transfer tags for multiplex genetic analysis. [source] A continuous flow mass spectrometry technique of argon isotope measurement for K/Ar geochronology,RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 16 2009Alexander V. Ignatiev A new method for the measurement of argon isotope composition in a continuous flow of helium for potassium/argon geochronology is described. Extraction of argon from geological samples in multiple-sample holders was carried out in a chamber by heating with a continuous Nd-YAG laser. The extracted and pre-concentrated argon is passed through a chromatographic capillary column in a flow of helium. Argon is separated from possible contaminants in the column and is injected through an open split into the ion source of an isotope ratio mass spectrometer. Measurement of the 36Ar, 38Ar and 40Ar isotopes was carried out in dynamic mode, using a triple-collector ion detector. These experiments have shown that continuous flow mass spectrometry can be used for the analysis of radiogenic argon in picogram quantities with an accuracy that is satisfactory for the solution of many geochronological problems. The method of argon isotope measurement in a continuous flow of helium is an alternative to the measurement of argon isotopes in the static mode. The sensitivity and accuracy of argon measurement by this method are comparable with those provided by the classical static method. The measurement of argon isotopes in a continuous flow of helium is simpler and more reliable than measurement in the static mode. Copyright © 2009 John Wiley & Sons, Ltd. [source] Enucleation of renal cell carcinoma with ablation of the tumour baseBJU INTERNATIONAL, Issue 6 2008Alexander Kutikov OBJECTIVE To retrospectively assess the effectiveness of cancer control with enucleation of renal cell carcinoma (RCC), which is surgically expedient, allows preservation of maximal renal parenchyma, and makes intraoperative renal ischaemia unnecessary, by two surgeons routinely enucleating renal tumours and ablating the tumour bed with argon beam and the Nd-YAG laser. PATIENTS AND METHODS Between 1996 and 2006 at our institution, 97 patients had RCC enucleated, with ablation of the tumour base. Patients with lesions other than RCC and those with von Hippel-Lindau disease or Birt-Hogg-Dube syndrome were excluded from the study. The mean follow-up was 24.9 months. Patients were evaluated for RCC recurrence with cross-sectional imaging at least every 6 months for the first 2 years and then annually thereafter. RESULTS The mean (median, range) tumour size was 2.8 (2.5, 0.8,7.0) cm. Of the 97 patients only one had disease progression after a mean follow-up of 24.9 months. This patient presented with a solitary grade 2 clear cell RCC and had a local recurrence 30 months after original surgery. CONCLUSIONS The present series and other available clinical data suggest that enucleation with cavity ablation is an oncologically sound approach that is simple, versatile and obviates the need for renal ischaemia. [source] | |||||||||||||