Dialysezentrum Potsdam

PurposeSnoring is the most common symptom in patients experiencing obstructive sleep apnea (OSA) and is reported by up to 94% of those affected. It has already been extensively proven that snoring of patients with OSA acoustically differs significantly from habitual snoring. For this study, snoring in patients with OSA is analyzed by its different components: pitch, formants (F1-F3), formant-ratio F2/F1, harmonic-noise-ratio (HNR), spectral energy ratio (SER). The objective of this study is to determine whether one or more acoustic parameters exhibit significant alterations or distinctive features immediately preceding an apneic episode, as compared to the patterns observed during simple snoring in individuals with obstructive sleep apnea (OSA). Identifying such preapneic indicators could facilitate the prediction of subsequent apnea events. With further technological advances and greater standardization, acoustical analysis could play a central role in the diagnosis and treatment of snoring and sleep apnea.MethodsBased on the “Munich-Passau Snore Sound Corpus” (MPSSC) as one of the world’s largest data sets for snoring sounds, retrospective data, consisting of 219 patients with OSA, were obtained using drug-induced sleep endoscopy (DISE). The mentioned components were retrieved and analyzed with the open source software „Praat“. Statistical testing was done with t-tests (Student and Welch) and Mann-Whitney-U-test.ResultsFor four parameters (F1, F2/F1, HNR, logSER) there are statistically significant differences between continuous/simple and preapneic snoring sounds.ConclusionsPreapneic snoring sounds seem to have different characteristics than continuous/simple snoring sounds. With further research, a simple acoustic differentiation for various diagnostic purposes could become possible.

Abstract Camelid antibodies are of special interest because some of them belong to immunoglobulin subclasses (IgG2 and IgG3) which are build up only by heavy chains. To use such antibodies for practical application we need specific identification tools. Immunoglobulins llama (Lama glama) were isolated by Protein G (IgG3 and IgG1) and Protein A (IgG2) sepharose. Fab Fragments were generated from llama IgG1 by papain digestion. Balb/c mice were immunized against the three different IgG subtypes and the Fab fragments and monoclonal antibodies were produce by hybridoma technology. We were hitherto able to obtain the following purified monoclonal antibodies (moAb): - moAb reacting to all subtypes with identical binding strength, - moAb that preferentially bind the conventional IgG1, - moAb that bind only IgG1. All generated monoclonal antibodies react against immunoglobulins from new world (llama and alpaca) and old world camelids (bactrian camel and dromedary) but show no cross reactivity with immunoglobulins from other species (rat, mouse, sheep, rabbit, goat, chicken and human). The monoclonal antibodies are suitable to detect camelid antibodies by enzyme immunoassay (ELISA) but not in western blots, indicating that the binding epitops are discontinuous. The production of monoclonal mouse antibodies binding to camelid heavy chain only antibodies is subject for future experiments.