Automatic sleep staging from ventilator signals in non-invasive ventilation

AbstractNon-invasive ventilation (NIV), a recognized treatment for chronic hypercapnic respiratory failure, is predominantly applied at night. Nevertheless, the quality of sleep is rarely evaluated due to the required technological complexity. A new technique for automatic sleep staging is here proposed for patients treated by NIV. This new technique only requires signals (airflow and hemoglobin oxygen saturation) available in domiciliary ventilators plus a photo-plethysmogram, a signal already managed by some ventilators. Consequently, electroencephalogram, electrooculogram, electromyogram, and electrocardiogram recordings are not needed. Cardiorespiratory features are extracted from the three selected signals and used as input to a Support Vector Machine (SVM) multi-class classifier. Two different types of sleep scoring were investigated: the first type was used to distinguish three stages (wake, REM sleep and nonREM sleep), and the second type was used to evaluate five stages (wake, REM sleep, N1, N2 and N3 stages). Patient-dependent and patient-independent classifiers were tested comparing the resulting hypnograms with those obtained from visual/manual scoring by a sleep specialist. An average accuracy of 91% (84%) was obtained with three-stage (five-stage) patient-dependent classifiers. With patient-independent classifiers, an average accuracy of 78% (62%) was obtained when three (five) sleep stages were scored. Also if the PPG-based and flow features are left out, a reduction of 4.5% (resp. 5%) in accuracy is observed for the three-stage (resp. five-stage) cases. Our results suggest that long-term sleep evaluation and nocturnal monitoring at home is feasible in patients treated by NIV. Our technique could even be integrated into ventilators

Validity of the relative percent concept for equating training intensity

The validity of the relative percent concept for equating training intensity was investigated using the point of metabolic acidosis (anaerobic threshold) as the criterion variable. Percent oxygen uptake, heart rate and metabolic acidosis were determined at 60, 70, and 80% of max heart rate on a bicycle ergometer test ( N =31). At 60 and 70% of max heart rate only one individual was definitely in metabolic acidosis. At 80% max heart rate 17 subjects were working at a level above the point of metabolic acidosis while 14 were working at or below this point. Thus, it was suggested that even if subjects are exercising at the same relative percent maximum HR, the metabolic stress using metabolic acidosis as the criterion is not constant across subjects. It was further shown that the regression of percent O 2 max on percent max HR was a spurious one resulting in poor prediction of individual O 2 values. The data presented suggest that the relative percent concept for equating exercise or subsequent training intensity needs careful re-evaluation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47421/1/421_2004_Article_BF00421445.pd

Perfil epidemiológico do câncer de laringe no Hospital de Clínicas de Porto Alegre

OBJECTIVES: The aim was to document the distribution and pattern of behavior of this tumor among our patients.MATERIALS AND METHODS: A retrospective study of patients with diagnosis of laryngeal cancer seen in the Hospital de Clínicas de Porto Alegre between 1990 to1996 was carried out.RESULTS: There were 242 cases, the majority of whom were from the white race (94,2%). The peak incidence was in the seventh decade of life and male to femaleratio was 15:1. The most common histological type was squamous cell carcinoma (98,76%) and by site, glottic involvement was the most frequent (44,7%), and so themost common symptom at presentation was hoarseness (76,5%). Supraglottic tumors presented, mainly, with dysphagia and the transglottics with dyspnea. As to staging, 43,3% were in IV stage at the diagnosis. The supraglottic tumors were, mainly, in the stage IV (38,3%), while the majority of glottic tumors (74,2%) were in the stage I, its reflect a worse prognosis for the supraglottic tumors. The total surgery was the mostfrequent treatment performed (50,7%).CONCLUSIONS: The laryngeal cancer diagnosis in the Hospital de Clínicas de Porto Alegre is done at a late stage, making the patient’s prognosis really reserved.OBJETIVO: O objetivo foi documentar a distribuição e o padrão de comportamento deste tumor entre os nossos pacientes.MATERIAIS E MÉTODOS: Foi realizado um estudo retrospectivo dos pacientes com diagnóstico de câncer de laringe atendidos no Hospital de Clínicas de Porto Alegre entre 1990 e 1996.RESULTADOS: Foram encontrados 242 casos, a maioria da raça branca (94,2%). A divisão por faixa etária mostrou um pico do ocorrência na sétima década de vida e a proporção de homens em relação à mulheres foi de 15:1. O tipo histológico maiscomum foi carcinoma epidermóide (98,76%) e o sítio mais freqüentemente acometido foi a glote (44,7%), conseqüentemente, o sintoma mais comum na apresentação foi a disfonia (76,5%). Os pacientes com tumores na supraglote apresentaram, principalmente, disfagia e, aqueles com tumores transglóticos, dispnéia. Quanto ao estadiamento, 43,2% estavam no estágio IV no momento do diagnóstico. Os tumores localizados na supraglote estão relacionados com pior prognóstico, nesta amostra 38,3% dos pacientes com câncer na supraglote estavam no estágio IV, enquanto quea maioria dos tumores glóticos (74,2%) estavam no estágio I. A cirurgia total foi o tratamento mais realizado (50,7%).CONCLUSÃO: O diagnóstico do câncer de laringe no Hospital de Clínicas de Porto Alegre é feito, em sua maior parte, em estágio avançado, tornando o prognóstico desses pacientes bastante reservado

Patologia ossicular na otite média crônica: implicações clínicas

OBJECTIVE: To compare the presence of ossicular pathologies in chronic otitis media in patients with perforated and those with and without tympanic membranes.MATERIALS AND METHODS: This study was based on histological analysis through optic microscopy. Out of 1.382 human temporal bones, we selected 144 that presented with tissue alterations compatible with chronic otitis media. These bones were collected from 96 individuals, 55 male and 41 female, aged from 10 to 88 years. Only 28 had perforated tympanic membranes.RESULTS: The analysis of the temporal bones indicated as the most common findings granulation tissue, ossicular alterations, tympanosclerosis, tympanic perforation, and cholesterol granuloma and cholesteatoma. The alterations found in this study revealed that the anvil is the most commonly affected ossicle, followed by the stapes and the malleus.CONCLUSIONS: The comparative analysis of perforated and non-perforated human temporal bones indicated that the two groups were similar regarding ossicular pathology.OBJETIVO: Comparar a presença de alterações ossiculares na otite média crônica em pacientes com membrana timpânica íntegra e com tímpano perfurado.MATERIAIS E MÉTODOS: Este estudo foi baseado em uma análise histológica através de microscopia ótica. De um grupo de 1.382 ossos temporais humanos, 144 foram escolhidos por apresentarem alterações teciduais compatíveis com otite média crônica. Estes ossos foram retirados de 96 indivíduos, 55 do sexo masculino e 41 do sexo feminino, com idades que variavam de 10 meses a 88 anos. Apenas 28 apresentavam a membrana timpânica perfurada, enquanto 116 ossos temporais humanos a tinham íntegra. RESULTADOS: A análise dos ossos temporais humanos apontou como os achados mais comuns o tecido de granulação, as alterações ossiculares, a timpanosclerose, a perfuração timpânica, o granuloma de colesterol e o colesteatoma. O perfil das alterações encontradas neste estudo mostram a bigorna como o ossículo mais atingido, seguido pelo estribo e pelo martelo.CONCLUSÕES: A análise comparativa dos ossos temporais com e sem perfurações da membrana timpânica indicaram que os grupos eram similares em relação à patologia ossicular

The HY5-PIF regulatory module coordinates light and temperature control of photosynthetic gene transcription

The ability to interpret daily and seasonal alterations in light and temperature signals is essential for plant survival. This is particularly important during seedling establishment when the phytochrome photoreceptors activate photosynthetic pigment production for photoautotrophic growth. Phytochromes accomplish this partly through the suppression of phytochrome interacting factors (PIFs), negative regulators of chlorophyll and carotenoid biosynthesis. While the bZIP transcription factor long hypocotyl 5 (HY5), a potent PIF antagonist, promotes photosynthetic pigment accumulation in response to light. Here we demonstrate that by directly targeting a common promoter cis-element (G-box), HY5 and PIFs form a dynamic activation-suppression transcriptional module responsive to light and temperature cues. This antagonistic regulatory module provides a simple, direct mechanism through which environmental change can redirect transcriptional control of genes required for photosynthesis and photoprotection. In the regulation of photopigment biosynthesis genes, HY5 and PIFs do not operate alone, but with the circadian clock. However, sudden changes in light or temperature conditions can trigger changes in HY5 and PIFs abundance that adjust the expression of common target genes to optimise photosynthetic performance and growth

Molecular Electrostatic Potential and Chemometric Techniques as Tools to Design Bioactive Compounds

In this chapter, firstly, we briefly review aspects of the approximation of quantum chemistry, molecular electrostatic potential (MEP), and chemometrics techniques, which are accredited as important tools in the development of chemical science and are frequently used in the study and design of bioactive compounds. Ultimately, we use MEP and pattern recognition (PR) techniques as tools to design nitrofuran compounds with biological activity against Trypanosoma cruzi (T. cruzi). PR models (PCA, HCA, KNN, SDA, and SIMCA) were constructed and demonstrated that 23 nitrofurans can be classified into two classes or groups: more active and less active according to their degrees of activity against T. cruzi. Properties such as charge on the N atom of the nitro group (QN1); the difference between the highest occupied molecular orbital (HOMO) energy and the lowest unoccupied molecular orbital (LUMO) energy (GAP energy); molecular representation of structure based on electron diffraction code of signal 5, unweighted (Mor05u); and Moriguchi water–octanol partition coefficient (MlogP) are responsible for the classification into more active and less active studied nitrofurans. It is interesting to notice that these properties represent three distinct classes of interactions between the nitrofurans and the biological receptor: electronic (QN1 and GAP energy), steric (Mor05u), and hydrophobic (MlogP). The results of the application of PR models on the validation set evidenced two nitrofuran compounds (compounds 25 and 30) as more promising for synthesis and biological assays, which in the future can be used to validate our PR models

Quantum Mechanical Approaches for Piezoelectricity Study in Perovskites

In this chapter, we show the procedures we have been used to theoretically investigate the piezoelectric effects in perovskites. The construction of extended basis sets using the generator coordinate Hartree-Fock (GCHF) method is shown, as well as the strategies used to contract extended basis sets and to evaluate their quality in molecular calculations. Besides, we show adequate procedures to choice polarization and diffuse functions to best represent the studied crystal. In addition, we also discuss conditions under which GCHF basis sets and standard basis sets from literature can be used to theoretical investigation of piezoelectricity in perovskites. We finalize the chapter presenting and discussing the results for investigations of piezoelectricity with standard basis sets for barium and lanthanum titanates. To conclude, we present evidences that BaTiO3 and LaTiO3 may have piezoelectric properties caused by electrostatic interactions

Avaliação da orelha contralateral em pacientes submetidos a cirurgia de otite média crônica no HCPA

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Emprego da Ecocardiografia Convencional na Avaliaçao de Pacientes com Miocardiopatia Dilatada, candidatos à Terapia de Ressincronizaçao

O advento da ressincronizaçao cardíaca (RC) representou um enorme avanço no campo da terapêutica da insuficiência cardíaca. No entanto, aproximadamente 30% dos pacientes nao respondem à RC, o que pode estar relacionado aos critérios de seleçao. A ecocardiografia-doppler convencional vem auxiliando na seleçao dos possíveis candidatos à RC, no ajuste da programaçao para cada paciente e na avaliaçao dos resultados agudos e a longo prazo