Indirect fluorescence laryngoscopy in the diagnosis of precancerous and cancerous laryngeal lesions.

Indirect fluorescence endoscopy of the larynx has proven to facilitate the detection and delineation of precancerous and cancerous lesion. The different methods are easy to handle and can be performed on an outpatient basis. Early diagnosis of laryngeal cancer and its precursor lesions is simplified. The aim of the present study is to compare indirect autofluorescence laryngoscopy to 5-ALA-induced PPIX fluorescence laryngoscopy. In a prospective study, 56 patients with suspected precancerous or cancerous lesions were primarily investigated by indirect autofluorescence laryngoscopy. In a second step 5-ALA-NaCl (0.6%) was topically applied to the larynx by inhalation, and indirect fluorescence laryngoscopy repeated 2 h after application. Autofluorescence as well as 5-ALA-induced fluorescence was induced by filtered light (375-440 nm) of a xenon short arc lamp and processed by a CCD camera system (D-light-AF System, Storz, Tuttlingen, Germany). White-light and fluorescence images were digitally recorded, immediately assessed for diagnosis and finally compared to pathohistological findings. Inconspicuous laryngeal mucosa presented a typical green fluorescence signal in autofluorescence endoscopy, which turned blue during 5-ALA-laryngoscopy. Precancerous and cancerous lesions displayed a loss of autofluorescence in autofluorescence endoscopy whereas increased protoporphyrin IX fluorescence could be observed in 5-ALA laryngoscopy. Both imaging techniques were suitable to distinguish benign from precancerous or cancerous lesions. In contrast PPIX fluorescence was easily recognized in scarred vocal folds. According to our results, both non-invasive fluorescence imaging techniques are useful in the early diagnosis of laryngeal cancer. Moreover autofluorescence can be used immediately without drug application and possible side effects. 5-ALA-induced fluorescence seems to be more suited for diagnostic examination of mucosal lesions in recurrent precancerous and cancerous lesions after surgery.

Spectrometric measurement in laryngeal cancer.

Only early diagnosis of laryngeal cancer can prevent major or mutilating treatment. Recently, autofluorescence endoscopy has been developed to enhance endoscopic information and succeeded in facilitating the detection and demarcation of precancerous lesions, carcinoma in situ and cancer of the larynx. The aim of the present study is to quantify autofluorescence imaging by spectroscopy in order to validate the above mentioned findings. In a prospective study, 42 patients with suspected one-sided precancerous or cancerous lesions of the vocal folds were investigated during microlaryngoscopy. Autofluorescence (AF) was induced by filtered blue light (375-440 nm) of a xenon short arc lamp and processed by a CCD camera system (D-light AF System, STORZ, Germany). Autofluorescence images were gathered in a contact mode. For spectrometric measurements an optical multi channel analyzer (AVS-USB 2000, Avantes, The Netherlands) was applied. The results were compared to pathohistological findings. Under blue light excitation normal mucosa presented a bright green fluorescence. Intensity increased from the ventricular folds to the subglottic area. Averaged spectra of the normal laryngeal mucosa demonstrated different fluorescence maxima at 475, 515, 550, 600 and 630 nm. Highest intensity was measured at 515 nm explaining the green appearance of the autofluorescence picture. In contrast, precancerous as well as cancerous lesions showed a significant decrease in autofluorescence intensity with a reddish-violet color. Highest loss of autofluorescence intensity was measured at 515 nm. At this wave length intensity dropped 70% on average in comparison to the regularly appearing contralateral vocal fold. In contrast to 515 nm, the loss of intensity at 630 nm amounted to 38%. Sensitivity amounted to 97% and specificity to 82%. Comparable to autofluorescence endoscopy a differentiation between precancerous and cancerous lesions could not be detected. The reason for the loss of autofluorescence may predominantly be caused by mucosal thickening but also by changes in metabolism and higher nuclei density.

The influence of several intravenous anaesthetics on the chemotaxis of human monocytes in vitro.

Monocytes play a very important part in humoral as well as in cell-mediated immunity. At present, however, the knowledge of the influence of anaesthetic agents on the functions of monocytes is limited. In the present study, the effects of thiopentone, methohexitone, ketamine, midazolam, droperidol, propofol, etomidate, and fentanyl on monocyte chemotaxis were examined in vitro using a 48-well microchemotaxis chamber. Clinically relevant concentrations of ketamine, midazolam, and droperidol significantly (P < or = 0.05) inhibited chemotaxis. For that reason, it is possible that these anaesthetics impair the immunological system in vivo. This possibility should be further examined.