The use of intranasal glucocorticosteroids in patients with chronic rhinosinusitis in the preoperative period

Introduction. Chronic rhinosinusitis is a disease that occurs everywhere, characterized by inflammation of the mucous membrane of the paranasal sinuses and nasal cavity. If it is impossible to eliminate the causes of the recurrent disease with medical therapy, the use of surgical treatment help to recover the normal functioning of the ostium, including the ostiomeatal complex to improve ventilation and drainage of the paranasal sinuses and recover nasal breathing to relieve chronic inflammation.Purpose of the study. Assessment of the degree of intraoperative bleeding in patients with chronic rhinosinusitis.Materials and methods. On the basis of the FGBU SPB Research Institute of ENT of the Ministry of Health of the Russian Federation in the period from 2020 to 2021. the study of the effect of local intranasal glucocorticosteroids (INGKS) in the intraoperative period in patients with chronic polypous rhinosinusitis was carried out. The total amount of blood loss during surgery for chronic polypous rhinosinusitis in patients who used mometasone furoate preoperatively and in patients not taking topical hormonal drugs was analyzed.Results. In the study group, the average blood loss per operation was 257 ml, in the control group – 401 ml. In patients who took intranasal glucocorticosteroids during surgery, the intensity of bleeding is less pronounced. Undoubtedly, there are many reasons that affect the intensity of bleeding in general, however, a decrease in the inflammatory response in the nasal cavity and a decrease in inflammatory metabolites have a beneficial effect on the state of the nasal mucosa.Conclusion. The use of intranasal glucocorticosteroids in the preoperative period has a positive effect on reducing the inflammatory process in the nasal cavity, which helps to reduce the intensity of intraoperative bleeding

A Statistically Rigorous Test for the Identification of Parent−Fragment Pairs in LC-MS Datasets

Untargeted global metabolic profiling by liquid chromato-graphy−mass spectrometry generates numerous signals that are due to unknown compounds and whose identification forms an important challenge. The analysis of metabolite fragmentation patterns, following collision-induced dissociation, provides a valuable tool for identification, but can be severely impeded by close chromatographic coelution of distinct metabolites. We propose a new algorithm for identifying related parent−fragment pairs and for distinguishing these from signals due to unrelated compounds. Unlike existing methods, our approach addresses the problem by means of a hypothesis test that is based on the distribution of the recorded ion counts, and thereby provides a statistically rigorous measure of the uncertainty involved in the classification problem. Because of technological constraints, the test is of primary use at low and intermediate ion counts, above which detector saturation causes substantial bias to the recorded ion count. The validity of the test is demonstrated through its application to pairs of coeluting isotopologues and to known parent−fragment pairs, which results in test statistics consistent with the null distribution. The performance of the test is compared with a commonly used Pearson correlation approach and found to be considerably better (e.g., false positive rate of 6.25%, compared with a value of 50% for the correlation for perfectly coeluting ions). Because the algorithm may be used for the analysis of high-mass compounds in addition to metabolic data, we expect it to facilitate the analysis of fragmentation patterns for a wide range of analytical problems

Structural Organization of the 19S Proteasome Lid: Insights from MS of Intact Complexes

The 26S proteasome contains a 19S regulatory particle that selects and unfolds ubiquitinated substrates for degradation in the 20S catalytic particle. To date there are no high-resolution structures of the 19S assembly, nor of the lid or base subcomplexes that constitute the 19S. Mass spectra of the intact lid complex from Saccharomyces cerevisiae show that eight of the nine subunits are present stoichiometrically and that a stable tetrameric subcomplex forms in solution. Application of tandem mass spectrometry to the intact lid complex reveals the subunit architecture, while the coupling of a cross-linking approach identifies further interaction partners. Taking together our results with previous analyses we are able to construct a comprehensive interaction map. In summary, our findings allow us to identify a scaffold for the assembly of the particle and to propose a regulatory mechanism that prevents exposure of the active site until assembly is complete. More generally, the results highlight the potential of mass spectrometry to add crucial insight into the structural organization of an endogenous, wild-type complex