1,438 research outputs found

    The role of the fibreoptic bronchoscope in otorhinolaryngological practice

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    Flexible fibreoptic bronchoscope has been employed in the examination of the nasopharynx, pharynx, larynx, trachea, bronchus and intrathoracic oesophagus under local anaesthesia. It is used either for diagnostic or therapeutic purposes. A total of 1690 procedures have been performed with no complication. The indications and findings in these procedures are listed. The advantages and limitations of the use of flexible fibreoptic bronchoscope as a 'panendoscopic examination' instrument are discussed.published_or_final_versio

    A novel YOLO-Based real-time people counting approach

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    Real-time people counting from video records is a main building bloc for many applications in smart cities. In practice, this task usually encounters many problems, like the lack of real-time processing of the recorded videos or the occurrence of errors due to irrelevant people being counted. To overcome the above issues, we propose a novel real-time people counting approach dubbed YOLO-PC (YOLO based People Counting)

    A simulation study for comparing testing statistics in response-adaptive randomization

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    <p>Abstract</p> <p>Background</p> <p>Response-adaptive randomizations are able to assign more patients in a comparative clinical trial to the tentatively better treatment. However, due to the adaptation in patient allocation, the samples to be compared are no longer independent. At large sample sizes, many asymptotic properties of test statistics derived for independent sample comparison are still applicable in adaptive randomization provided that the patient allocation ratio converges to an appropriate target asymptotically. However, the small sample properties of commonly used test statistics in response-adaptive randomization are not fully studied.</p> <p>Methods</p> <p>Simulations are systematically conducted to characterize the statistical properties of eight test statistics in six response-adaptive randomization methods at six allocation targets with sample sizes ranging from 20 to 200. Since adaptive randomization is usually not recommended for sample size less than 30, the present paper focuses on the case with a sample of 30 to give general recommendations with regard to test statistics for contingency tables in response-adaptive randomization at small sample sizes.</p> <p>Results</p> <p>Among all asymptotic test statistics, the Cook's correction to chi-square test (<it>T</it><sub><it>MC</it></sub>) is the best in attaining the nominal size of hypothesis test. The William's correction to log-likelihood ratio test (<it>T</it><sub><it>ML</it></sub>) gives slightly inflated type I error and higher power as compared with <it>T</it><sub><it>MC</it></sub>, but it is more robust against the unbalance in patient allocation. <it>T</it><sub><it>MC </it></sub>and <it>T</it><sub><it>ML </it></sub>are usually the two test statistics with the highest power in different simulation scenarios. When focusing on <it>T</it><sub><it>MC </it></sub>and <it>T</it><sub><it>ML</it></sub>, the generalized drop-the-loser urn (GDL) and sequential estimation-adjusted urn (SEU) have the best ability to attain the correct size of hypothesis test respectively. Among all sequential methods that can target different allocation ratios, GDL has the lowest variation and the highest overall power at all allocation ratios. The performance of different adaptive randomization methods and test statistics also depends on allocation targets. At the limiting allocation ratio of drop-the-loser (DL) and randomized play-the-winner (RPW) urn, DL outperforms all other methods including GDL. When comparing the power of test statistics in the same randomization method but at different allocation targets, the powers of log-likelihood-ratio, log-relative-risk, log-odds-ratio, Wald-type Z, and chi-square test statistics are maximized at their corresponding optimal allocation ratios for power. Except for the optimal allocation target for log-relative-risk, the other four optimal targets could assign more patients to the worse arm in some simulation scenarios. Another optimal allocation target, <it>R</it><sub><it>RSIHR</it></sub>, proposed by Rosenberger and Sriram (<it>Journal of Statistical Planning and Inference</it>, 1997) is aimed at minimizing the number of failures at fixed power using Wald-type Z test statistics. Among allocation ratios that always assign more patients to the better treatment, <it>R</it><sub><it>RSIHR </it></sub>usually has less variation in patient allocation, and the values of variation are consistent across all simulation scenarios. Additionally, the patient allocation at <it>R</it><sub><it>RSIHR </it></sub>is not too extreme. Therefore, <it>R</it><sub><it>RSIHR </it></sub>provides a good balance between assigning more patients to the better treatment and maintaining the overall power.</p> <p>Conclusion</p> <p>The Cook's correction to chi-square test and Williams' correction to log-likelihood-ratio test are generally recommended for hypothesis test in response-adaptive randomization, especially when sample sizes are small. The generalized drop-the-loser urn design is the recommended method for its good overall properties. Also recommended is the use of the <it>R</it><sub><it>RSIHR </it></sub>allocation target.</p

    ?2-Microglobulin Amyloid Fibril-Induced Membrane Disruption Is Enhanced by Endosomal Lipids and Acidic pH

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    Although the molecular mechanisms underlying the pathology of amyloidoses are not well understood, the interaction between amyloid proteins and cell membranes is thought to play a role in several amyloid diseases. Amyloid fibrils of ?2-microglobulin (?2m), associated with dialysis-related amyloidosis (DRA), have been shown to cause disruption of anionic lipid bilayers in vitro. However, the effect of lipid composition and the chemical environment in which ?2m-lipid interactions occur have not been investigated previously. Here we examine membrane damage resulting from the interaction of ?2m monomers and fibrils with lipid bilayers. Using dye release, tryptophan fluorescence quenching and fluorescence confocal microscopy assays we investigate the effect of anionic lipid composition and pH on the susceptibility of liposomes to fibril-induced membrane damage. We show that ?2m fibril-induced membrane disruption is modulated by anionic lipid composition and is enhanced by acidic pH. Most strikingly, the greatest degree of membrane disruption is observed for liposomes containing bis(monoacylglycero)phosphate (BMP) at acidic pH, conditions likely to reflect those encountered in the endocytic pathway. The results suggest that the interaction between ?2m fibrils and membranes of endosomal origin may play a role in the molecular mechanism of ?2m amyloid-associated osteoarticular tissue destruction in DRA

    Robot-assisted Radical Cystectomy Versus Open Radical Cystectomy: A Systematic Review and Meta-analysis of Perioperative, Oncological, and Quality of Life Outcomes Using Randomized Controlled Trials

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    CONTEXT: Differences in recovery, oncological, and quality of life (QoL) outcomes between open radical cystectomy (ORC) and robot-assisted radical cystectomy (RARC) for patients with bladder cancer are unclear. OBJECTIVE: This review aims to compare these outcomes within randomized trials of ORC and RARC in this context. The primary outcome was the rate of 90-d perioperative events. The secondary outcomes included operative, pathological, survival, and health-related QoL (HRQoL) measures. EVIDENCE ACQUISITION: Systematic literature searches of MEDLINE, Embase, Web of Science, and clinicaltrials.gov were performed up to May 31, 2022. EVIDENCE SYNTHESIS: Eight trials, reporting 1024 participants, were included. RARC was associated with a shorter hospital length of stay (LOS; mean difference [MD] 0.21, 95% confidence interval [CI] 0.03-0.39, p = 0.02) than and similar complication rates to ORC. ORC was associated with higher thromboembolic events (odds ratio [OR] 1.84, 95% CI 1.02-3.31, p = 0.04). ORC was associated with more blood loss (MD 322 ml, 95% CI 193-450, p < 0.001) and transfusions (OR 2.35, 95% CI 1.65-3.36, p < 0.001), but shorter operative time (MD 76 min, 95% CI 39-112, p < 0.001) than RARC. No differences in lymph node yield (MD 1.07, 95% CI -1.73 to 3.86, p = 0.5) or positive surgical margin rates (OR 0.95, 95% CI 0.54-1.67, p = 0.9) were present. RARC was associated with better physical functioning or well-being (standardized MD 0.47, 95% CI 0.29-0.65, p < 0.001) and role functioning (MD 8.8, 95% CI 2.4-15.1, p = 0.007), but no improvement in overall HRQoL. No differences in progression-free survival or overall survival were seen. Limitations may include a lack of generalization given trial patients. CONCLUSIONS: RARC offers various perioperative benefits over ORC. It may be more suitable in patients wishing to avoid blood transfusion, those wanting a shorter LOS, or those at a high risk of thromboembolic events. PATIENT SUMMARY: This study compares robot-assisted keyhole surgery with open surgery for bladder cancer. The robot-assisted approach offered less blood loss, shorter hospital stays, and fewer blood clots. No other differences were seen

    Knocking at the brain’s door: intravital two-photon imaging of autoreactive T cell interactions with CNS structures

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    Since the first applications of two-photon microscopy in immunology 10 years ago, the number of studies using this advanced technology has increased dramatically. The two-photon microscope allows long-term visualization of cell motility in the living tissue with minimal phototoxicity. Using this technique, we examined brain autoantigen-specific T cell behavior in experimental autoimmune encephalitomyelitis, the animal model of human multiple sclerosis. Even before disease symptoms appear, the autoreactive T cells arrive at their target organ. There they crawl along the intraluminal surface of central nervous system (CNS) blood vessels before they extravasate. In the perivascular environment, the T cells meet phagocytes that present autoantigens. This contact activates the T cells to penetrate deep into the CNS parenchyma, where the infiltrated T cells again can find antigen, be further activated, and produce cytokines, resulting in massive immune cell recruitment and clinical disease

    Autoimmune and autoinflammatory mechanisms in uveitis

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    The eye, as currently viewed, is neither immunologically ignorant nor sequestered from the systemic environment. The eye utilises distinct immunoregulatory mechanisms to preserve tissue and cellular function in the face of immune-mediated insult; clinically, inflammation following such an insult is termed uveitis. The intra-ocular inflammation in uveitis may be clinically obvious as a result of infection (e.g. toxoplasma, herpes), but in the main infection, if any, remains covert. We now recognise that healthy tissues including the retina have regulatory mechanisms imparted by control of myeloid cells through receptors (e.g. CD200R) and soluble inhibitory factors (e.g. alpha-MSH), regulation of the blood retinal barrier, and active immune surveillance. Once homoeostasis has been disrupted and inflammation ensues, the mechanisms to regulate inflammation, including T cell apoptosis, generation of Treg cells, and myeloid cell suppression in situ, are less successful. Why inflammation becomes persistent remains unknown, but extrapolating from animal models, possibilities include differential trafficking of T cells from the retina, residency of CD8(+) T cells, and alterations of myeloid cell phenotype and function. Translating lessons learned from animal models to humans has been helped by system biology approaches and informatics, which suggest that diseased animals and people share similar changes in T cell phenotypes and monocyte function to date. Together the data infer a possible cryptic infectious drive in uveitis that unlocks and drives persistent autoimmune responses, or promotes further innate immune responses. Thus there may be many mechanisms in common with those observed in autoinflammatory disorders
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