Laser-Medizin: eine interdisziplin?re Zeitschrift ; Praxis, Klinik, Forschung最新文献

Zusammenfassung

Der 6. Internationale Jahreskongreß der Deutschen Gesellschaft für Laserzahnheilkunde e. V stellte ein aktuelles Forum für den Austausch zwischen Wissenschaftlern und klinischen Zahnärzten über neue Forschungsergebnisse und Entwicklungen im Bereich der Laserzahnheilkunde dar, die vom 31. 01. 1997 bis 2. 02. 1997 in Frankfurt in Fachvorträgen vorgestellt wurden. Der Frankfurter Kongreß ist das größte Forum der Laseranwendung in der Zahnmedizin in Deutschland.

Der Kongreß der Deutschen Gesellschaft für Laserzahnheilkunde e. V hat dieses Jahr bereits am Freitag den 31. 02. 1997 mit einer großen Zahl vielversprechender Vortragsthemen begonnen. Ab Freitagmittag fanden fachbegleitende Vorführungen und Workshops statt.

With the development of optical fibers capable of transmitting laser energy, lasers have steadily gained acceptance over the last decade for use in performing endoscopic and hysteroscopic surgical procedures. One such laser, the Nd-YAG, is particularly well suited for photocoagulation of the endometrium as a result of its high power and transmission ability through fibreoptics. The advent of hysteroscopic laser surgery has provided an alternative to hysterectomy in women with menorrhagia refractory to other forms of treatment. Experience in patients treated hysteroscopically with a Nd-YAG laser has demonstrated that excellent results were achieved.

We have started to use the side fire laser delivery fiber in combination with the bare fiber for optimization of the laser energy delivery during the endometrial ablation. This trial provided an ideal intrauterine laser energy delivery according to the uterine cavity geometry and light dosimetery distribution. The duration of technique was markedly shorter (average 25 min) than using only the bare fiber and the endometrial coagulation was efficient.

Successful restoration of audition in revision stapedotomies involves precise identification and correction of the pathological condition without traumatizing the inner ear. Conventional surgical procedures often lead to unsatisfactory audition results and inner ear damages. In revision stapedotomy, the CO² laser provides the ear surgeon with three important advantages over the conventional technique: 1. improved diagnostic and therapeutic precision, 2. better stabilization of the new prosthesis in the oval niche, and 3. reduction of inner ear trauma through non-contact atraumatic management.

The surgical procedure of revision stapedotomies with the CO² laser is discussed, and case examples are used to illustrate the diversity of pathological conditions that can be treated by CO² laser surgery. Our experience with revision CO² laser stapedotomy suggests an improvement of postoperative audition compared to the conventional technique and demonstrates a significant elimination of sensorineural deafness. The CO² laser enables the ear surgeon to precisely and reliably correct conduction deafness recurring after stapedotomy.

The ratio of the accumulated photosensitizer concentration to its injected dose is named the specific uptake ratio (SUR). Investigations on a photosensitizer's biodistribution using the parameter SUR offer a better understanding of the pharmacokinetic behaviours of different photosensitizers and render the comparison of different photosensitizers possible by overcoming the problem of using different sensitizer doses in different studies. The SUR of 13²-OH-BPME was recorded in mice bearing Lewis lung carcinoma after i.v administration of 7.8 αmole/kg body weight at different incubation time intervals. The photosensitizer was chemically extracted from selected tissues and concentrations were measured by absorption spectroscopy. The parenchymatous organs liver, spleen, and kidney as well as the lung showed maximum 13²-OH-BPME uptake ratios of 1.5 up 5.4 between 2 h and 4 h incubation times. The malignant tissue showed high 13²-OHBPME SUR between 2 h and 12 h post injection with a maximum SUR of 1.2 at 8 h incubation time. The 13²-OH-BPME SUR in muscle tissue, which represented the normal tumour surrounding tissue, and in the skin were very low and never exceeded 0.09 and 0.3 in muscle and skin, respectively. These results suggest that PDT using 13²-OH-BPME could be effective at a photosensitizer incubation time of about 8 h post injection, when the tumour 13²-OH-BPME SUR is maximum value, while muscle and skin exhibit minimum 13²-OH-BPME uptake. Therefore, phototoxic side effects on normal tissues in the tumour surrondings should not be induced.

Die in einem Gewebe akkumulierte Konzentration eines Photosensibilisators im Verhältnis zur verabreichten Gesamtdosis wird als Spezifische Aufnahmerate (specific uptake ratio, SUR) bezeichnet. Untersuchungen zur Sensibilisator-Bioverteilung unter Verwendung des Parameters SUR ermöglichen einen objektiven Vergleich der Pharmakokinetiken verschiedener Sensibilisatoren, indem das Problem der unterschiedlichen Dosen, die in den unterschiedlichen Studien beschrieben wurden, somit umgangen wird. Die SUR-Kinetik des 13²-Hydroxy-Bacteriopheophorbid a-Methylesters (13²-OH-BPME) wurde hier am Tumormodell des Lewis lung-Karzinoms in der Maus nach intravenöser Injektion von 7.8 αmol/kg Körpergewicht iffier einen Inkubationszeitraum von 168 h untersucht. Dafür wurde 13²-OH-BPME aus ausgewählten Organen bzw. Geweben chernisch extrahierty, und die Farbstoffkonzentrationen absorptionsspektroskopisch bestimmt. In den parenchymatösen Organen Leber, Milz und Niere sowie in der Lunge wurden maximale SUR-Werte von 1,5 bis 5,4 zwischen 2 h und 4 h nach Injektion detektiert. Das Tumorgewebe zeigte hohe 13²-OH-BPME-SUR während einer Inkubationsdauer von 2 h bis 12 h mit einer maximalen SUR von 1.2 nach 8 h Inkubation. In Muskelgewebe, das bier das Normalgewebe d