Cell Death and Ultrastructural Morphology of Femtosecond Laser-Assisted Anterior Capsulotomy

PURPOSE. To evaluate cell death and ultrastructural effects on capsulotomy specimens derived from femtosecond laser-assisted cataract surgery. METHODS. In 26 eyes, an anterior capsulotomy was performed using a femtosecond laser. In 10 eyes (group 1), the laser-pulse energy was set to 15 lJ using a rigid curved interface and in another 10 eyes (group 2) to 5 lJ using a curved interface combined with a soft contact lens. The control group (6 eyes, group 3) underwent manual anterior capsulorhexis using forceps. All extracted capsule specimens underwent cell death analysis using the TUNEL kit, ultrastructural analyses using atomic force microscopy (AFM), and scanning electron microscopy (SEM). Counterstaining was performed with 4 0 ,6-diamidino-2-phenylindol (DAPI) and hematoxylin-eosin (HE). RESULTS. Cell death was found in all capsule specimens along the cutting edge but was significantly more pronounced in group 1. DAPI and HE staining showed regular epithelial cell distribution with a demarcation line along the cutting edge of both laser groups, which was more pronounced in group 1. In AFM analysis, laser spot size in the femtosecond laser groups were in accordance with the preoperative planned size (P < 0.01). Cutting edges in SEM observations were smoother and more roundly shaped using 5 lJ (group 2). CONCLUSIONS. Cutting edges of femtosecond laser-performed capsulotomies are precise and laser spot lesions are within planned size. Cell death reaction depends on the laser pulse energy settings and can be reduced to the level observed in a manual capsulorhexis. Keywords: femtosecond laser, capsulotomy, capsulorhexis, laser energy, cell death, apoptosis, atomic force microscopy, scanning electron microscopy A precise and well-performed capsulorhexis is crucial to perform an uncomplicated cataract extraction, intraocular lens implantation, and centration. 1-3 This main step in cataract surgery and refractive lens exchange surgery is commonly performed manually. Femtosecond lasers are now changing how lens surgery is performed by becoming involved in the main steps of the surgical process: corneal incisions, capsulotomy, and lens fragmentation. Dick et al. 2 recently suggested a new terminology for opening the anterior lens capsule with a femtosecond laser: capsulotomy instead of capsulorhexis, as the femtosecond laser operates as a cutting knife by using focal photodisruption. Recent studies have already demonstrated that femtosecond laser-performed capsulotomies allow repeatable and precise sizing and centration; furthermore, they improve the safety of hydrodissection, nuclear fragmentation, and cortical cleanup. 10 During capsulotomy, the anterior capsule is being injured and epithelial cell death is induced. This effect might be stronger with the assistance of femtosecond lasers. Therefore, the purpose of this study was to investigate cell death reaction after anterior capsulotomy either performed by a femtosecond laser using different energy levels or manually by using forceps. Furthermore, laser spot lesions and cutting edge of all capsulotomy specimens were investigated on the ultrastructural level. METHODS The experimental study was approved by the ethics committee of the Goethe-University, Frankfurt am Main, Germany, and was performed in accordance with the Declaration of Helsinki at the Department of Ophthalmology, Goethe-University. In 26 eyes of 26 patients diagnosed with corticonuclear cataract formation anterior femtosecond laser-assisted capsulotomy (n ¼ 20) or manual capsulorhexis (n ¼ 6) using forceps was performed. In 10 eyes (group 1) that underwent femtosecond laser capsulotomy, the laser pulse energy was set to 15 lJ and applanation to the ocular surface was performed using a rigid curved interface. For another 10 eye

Irinotecan in patients with relapsed or cisplatin-refractory germ cell cancer: a phase II study of the German Testicular Cancer Study Group

Despite generally high cure rates in patients with metastatic germ cell cancer, patients with progressive disease on first-line cisplatin-based chemotherapy or with relapsed disease following high-dose salvage therapy exhibit a very poor prognosis. Irinotecan has shown antitumour activity in human testicular tumour xenografts in nude mice. We have performed a phase II study examining the single agent activity of irinotecan in patients with metastatic relapsed or cisplatin-refractory germ cell cancer. Refractory disease was defined as progression or relapse within 4 weeks after cisplatin-based chemotherapy or relapse after salvage high-dose chemotherapy with autologous stem cell support. Irinotecan was administered at a dose of 300 (−350) mg m−2 every 3 weeks. Response was evaluated every 4 weeks. Fifteen patients have been enrolled. Median age was 35 (19–53) years. Primary tumour localisation was gonadal/mediastinal in 12/3 patients. Patients had been pretreated with a median of six (4–12) cisplatin-containing cycles and 13 out of 15 patients had previously failed high-dose chemotherapy with blood stem cell support. Median number of irinotecan applications was two (1–3). Fourteen patients are assessable for response and all for toxicity. In one patient, no adequate response evaluation was performed. Toxicity was generally acceptable and consisted mainly of haematological side effects with common toxicity criteria 3° anaemia (two patients), common toxicity criteria 3° leukocytopenia (one patient) and common toxicity criteria 3° thrombocytopenia (three patients). Common toxicity criteria 3/4° non-haematological toxicity occurred in five patients (33%): 1×diarrhoea, 2×alopecia, 1×fever and in one patient worsening of pre-existing peripheral polyneuropathy from 1° to 4°. No response was observed to irinotecan therapy. Currently, 13 patients have died of the disease and two patients are alive with the disease. The patients included in our study exhibit similar prognostic characteristics as patients treated in previous trials evaluating new drugs in this setting. Irinotecan at a dose of 300–350 mg m−2 every 3 weeks appears to have no antitumour activity in patients with cisplatin-refractory germ cell cancer and, thus, further investigation in this disease is not justified