Analog circuit for real-time computation of respiratory mechanical impedance in sleep studies

The aim of this work was to develop a low-cost circuit for real-time analog computation of the respiratory mechanical impedance in sleep studies. The practical performance of the circuit was tested in six patients with obstructive sleep apnea. The impedance signal provided by the analog circuit was compared with the impedance calculated simultaneously with a conventional computerized system. We concluded that the low-cost analog circuit developed could be a useful tool for facilitating the real-time assessment of airway obstruction in routine sleep studies.

Effect of expiratory flow limitation on respiratory mechanical impedance: a model study

Large phasic variations of respiratory mechanical impedance (Zrs) have been observed during induced expiratory flow limitation (EFL) (M. Vassiliou, R. Peslin, C. Saunier, and C. Duvivier. Eur. Respir. J. 9: 779-786, 1996). To clarify the meaning of Zrs during EFL, we have measured from 5 to 30 Hz the input impedance (Zin) of mechanical analogues of the respiratory system, including flow-limiting elements (FLE) made of easily collapsible rubber tubing. The pressures upstream (Pus) and downstream (Pds) from the FLE were controlled and systematically varied. Maximal flow (Vmax) increased linearly with Pus, was close to the value predicted from wave-speed theory, and was obtained for Pus-Pds of 4-6 hPa. The real part of Zin started increasing abruptly with flow (V) >85%Vmax and either further increased or suddenly decreased in the vicinity of V¿max. The imaginary part of Zin decreased markedly and suddenly above 95%Vmax. Similar variations of Zin during EFL were seen with an analogue that mimicked the changes of airway transmural pressure during breathing. After pressure andV measurements upstream and downstream from the FLE were combined, the latter was analyzed in terms of a serial (Zs) and a shunt (Zp) compartment. Zs was consistent with a large resistance and inertance, and Zp with a mainly elastic element having an elastance close to that of the tube walls. We conclude that Zrs data during EFL mainly reflect the properties of the FLE.

Mechanical properties of cultured human airway smooth muscle cells from 0.05 to 0.4 Hz.

We investigated the rheological properties of living human airway smooth muscle cells in culture and monitored the changes in rheological properties induced by exogenous stimuli. We oscillated small magnetic microbeads bound specifically to integrin receptors and computed the storage modulus (G') and loss modulus (G") from the applied torque and the resulting rotational motion of the beads as determined from their remanent magnetic field. Under baseline conditions, G' increased weakly with frequency, whereas G" was independent of the frequency. The cell was predominantly elastic, with the ratio of G" to G' (defined as eta) being ~0.35 at all frequencies. G' and G" increased together after contractile activation and decreased together after deactivation, whereas eta remained unaltered in each case. Thus elastic and dissipative stresses were coupled during changes in contractile activation. G' and G" decreased with disruption of the actin fibers by cytochalasin D, but eta increased. These results imply that the mechanisms for frictional energy loss and elastic energy storage in the living cell are coupled and reside within the cytoskeleton.

La respiración en el canto

Aquest article pretén una aproximació al fenomen de la respiració aplicada a la veu humana i al cant. Es descriuen els tipus de respiració, el procés i les seves fases, la capacitat respiratòria com element essencial en el cant, i es presenta una col.lecció d'exercicis de respiració fàcils per adults i per infants, així com un llistat bibliogràfic bàsic i complementari.

Analog circuit for real-time computation of respiratory mechanical impedance in sleep studies

The aim of this work was to develop a low-cost circuit for real-time analog computation of the respiratory mechanical impedance in sleep studies. The practical performance of the circuit was tested in six patients with obstructive sleep apnea. The impedance signal provided by the analog circuit was compared with the impedance calculated simultaneously with a conventional computerized system. We concluded that the low-cost analog circuit developed could be a useful tool for facilitating the real-time assessment of airway obstruction in routine sleep studies.

Platelet-activating factor causes ventilation-perfusion mismatch in humans

We hypothesized that platelet-activating factor (PAF), a potent inflammatory mediator, could induce gas exchange abnormalities in normal humans. To this end, the effect of aerosolized PAF (2 mg/ml solution; 24 micrograms) on ventilation-perfusion (VA/Q) relationships, hemodynamics, and resistance of the respiratory system was studied in 14 healthy, nonatopic, and nonsmoking individuals (23 +/- 1 [SEM]yr) before and at 2, 4, 6, 8, 15, and 45 min after inhalation, and compared to that of inhaled lyso-PAF in 10 other healthy individuals (24 +/- 2 yr). PAF induced, compared to lyso-PAF, immediate leukopenia (P < 0.001) followed by a rebound leukocytosis (P < 0.002), increased minute ventilation (P < 0.05) and resistance of the respiratory system (P < 0.01), and decreased systemic arterial pressure (P < 0.05). Similarly, compared to lyso-PAF, PaO2 showed a trend to fall (by 12.2 +/- 4.3 mmHg, mean +/- SEM maximum change from baseline), and arterial-alveolar O2 gradient increased (by 16.7 +/- 4.3 mmHg) (P < 0.02) after PAF, because of VA/Q mismatch: the dispersion of pulmonary blood flow and that of ventilation increased by 0.45 +/- 0.1 (P < 0.01) and 0.29 +/- 0.1 (P < 0.04), respectively. We conclude that in normal subjects, inhaled PAF results in considerable immediate VA/Q inequality and gas exchange impairment. These results reinforce the notion that PAF may play a major role as a mediator of inflammation in the human lung.

Platelet-activating factor causes ventilation-perfusion mismatch in humans

We hypothesized that platelet-activating factor (PAF), a potent inflammatory mediator, could induce gas exchange abnormalities in normal humans. To this end, the effect of aerosolized PAF (2 mg/ml solution; 24 micrograms) on ventilation-perfusion (VA/Q) relationships, hemodynamics, and resistance of the respiratory system was studied in 14 healthy, nonatopic, and nonsmoking individuals (23 +/- 1 [SEM]yr) before and at 2, 4, 6, 8, 15, and 45 min after inhalation, and compared to that of inhaled lyso-PAF in 10 other healthy individuals (24 +/- 2 yr). PAF induced, compared to lyso-PAF, immediate leukopenia (P < 0.001) followed by a rebound leukocytosis (P < 0.002), increased minute ventilation (P < 0.05) and resistance of the respiratory system (P < 0.01), and decreased systemic arterial pressure (P < 0.05). Similarly, compared to lyso-PAF, PaO2 showed a trend to fall (by 12.2 +/- 4.3 mmHg, mean +/- SEM maximum change from baseline), and arterial-alveolar O2 gradient increased (by 16.7 +/- 4.3 mmHg) (P < 0.02) after PAF, because of VA/Q mismatch: the dispersion of pulmonary blood flow and that of ventilation increased by 0.45 +/- 0.1 (P < 0.01) and 0.29 +/- 0.1 (P < 0.04), respectively. We conclude that in normal subjects, inhaled PAF results in considerable immediate VA/Q inequality and gas exchange impairment. These results reinforce the notion that PAF may play a major role as a mediator of inflammation in the human lung.

Mètode psicofísic “cos-art”: relació amb l’emissió de la veu

Es presenten els resultats d’una investigació de caràcter qualitatiu -encara que s’ha utilitzat en algun moment l’estadística- pel que fa a la valoració que un grup d’alumnes de la Universitat Ramon Llull fa del mètode psicofísic Cos-Art com a treball que serveix per millorar l’emissió de la veu. Les tècniques i els instruments per a la recollida d’informació que s’han utilitzat han estat el diari de camp i el qüestionari. L’anàlisi de resultats mostra el treball global del Mètode com a efectiu. En blocs més específics, com poden ser els temes de respiració o llengua, entre altres, la freqüència més elevada en les respostes ha estat que el treball de Cos-Art els ha ajudat bastant. Per últim, un gran nombre d’alumnes consideren que el Mètode Cos-Art ajuda, de forma molt positiva, a prendre consciència d’un mateix.

Two distinct plant respiratory physiotypes might exist which correspond to fast-growing and slow-growing species

The origin of the carbon atoms in CO2 respired by leaves in the dark of several plant species has been studied using 13C/12C stable isotopes. This study was conducted using an open gas exchange system for isotope labeling that was coupled to an elemental analyser and further linked to an isotope ratio mass spectrometer (EA-IRMS) or coupled to a gas chromatography-combustion-isotope ratio mass spectrometer (GC-C-IRMS). We demonstrate here that the carbon, which is recently assimilated during photosynthesis, accounts for nearly ca. 50% of the carbon in the CO2 lost through dark respiration after illumination in fast-growing and cultivated plants and trees and, accounts for only ca. 10% in slow-growing plants. Moreover, our study shows that fast- growing plants, which had the largest percentages of newly fixed carbon of leaf-respired CO2 , were also those with the largest shoot/root ratios, whereas slow-growing plants showed the lowest shoot/root values.

Metabolic origin of δ15N values in nitrogenous compounds from Brassica napus L. leaves

Nitrogen isotope composition (δ15N) in plant organic matter is currently used as a natural tracer of nitrogen acquisition efficiency. However, the δ15N value of whole leaf material does not properly reflect the way in which N is assimilated because isotope fractionations along metabolic reactions may cause substantial differences among leaf compounds. In other words, any change in metabolic composition or allocation pattern may cause undesirable variability in leaf δ15N. Here, we investigated the δ15N in different leaf fractions and individual metabolites from rapeseed (Brassica napus) leaves. We show that there were substantial differences in δ15N between nitrogenous compounds (up to 30 ) and the content in (15N enriched) nitrate had a clear influence on leaf δ15N. Using a simple steady-state model of day metabolism, we suggest that the δ15N value in major amino acids was mostly explained by isotope fractionation associated with isotope effects on enzyme-catalysed reactions in primary nitrogen metabolism. δ15N values were further influenced by light versus dark conditions and the probable occurrence of alternative biosynthetic pathways. We conclude that both biochemical pathways (that fractionate between isotopes) and nitrogen sources (used for amino acid production) should be considered when interpreting the δ15N value of leaf nitrogenous compounds

Does ear C sink strength contributes to the overcoming of photosynthetic acclimation of wheat plants exposed to elevated CO2?

Wheat plants (Triticum durum Desf., cv. Regallo) were grown in the field to study the effects of contrasting [CO2] conditions (700 versus 370 μmol mol−1) on growth, photosynthetic performance, and C management during the post-anthesis period. The aim was to test whether a restricted capacity of sink organs to utilize photosynthates drives a loss of photosynthetic capacity in elevated CO2. The ambient 13C/12C isotopic composition (δ13C) of air CO2 was changed from-10.2 in ambient [CO2] to-23.6 under elevated [CO2] between the 7th and the 14th days after anthesis in order to study C assimilation and partitioning between leaves and ears. Elevated [CO2] had no significant effect on biomass production and grain filling, and caused an accumulation of C compounds in leaves. This was accompanied by up-regulation of phosphoglycerate mutase and ATP synthase protein content, together with down-regulation of adenosine diphosphate glucose pyrophosphatase protein. Growth in elevated [CO2] negatively affected Rubisco and Rubisco activase protein content and induced photosynthetic down-regulation. CO2 enrichment caused a specific decrease in Rubisco content, together with decreases in the amino acid and total N content of leaves. The C labelling revealed that in flag leaves, part of the C fixed during grain filling was stored as starch and structural C compounds whereas the rest of the labelled C (mainly in the form of soluble sugars) was completely respired 48 h after the end of labelling. Although labelled C was not detected in the δ13C of ear total organic matter and respired CO2, soluble sugar δ13C revealed that a small amount of labelled C reached the ear. The 12CO2 labelling suggests that during the beginning of post-anthesis the ear did not contribute towards overcoming flag leaf carbohydrate accumulation, and this had a consequent effect on protein expression and photosynthetic acclimation.

Reanimació cardiopulmonar sense ventilació

Aquest estudi emmarcat dins un treball de final del Màster en Promoció de la Salut m’ha servit per veure que encara hi ha un llarg recorregut a investigar en el camp de la reanimació cardiopulmonar. Les 3 línees sorgides son: com millorar la qualitat en RCP, buscar estratègies per augmentar les freqüències mitges de compressió toràcica externa i com ensenyar a retenir les tècniques de RCP Penso que totes elles s’aniran desenvolupant en els propers anys i que aquelles accions que vagin encaminades a millorar la supervivència de la principal causa de mort dels europeus en edat compreses entre els 35 i 36 anys hauria de ser una tasca prioritària en investigació

Nuevos planteamientos educativos del siglo XXI : el reto de los centros espec??ficos : la atenci??n educativo-sanitaria en el alumnado con precario estado de salud

Se presenta experiencia educativa que propone la inclusi??n en la escuela de alumnado plurideficiente gravemente afectado. Los objetivos son: favorecer el bienestar f??sico del alumnado plurideficiente gravemente afectado; crear un entorno saludable y acogedor que facilite sensaciones de estabilidad y seguridad en el alumnado; control de par??metros de salud: temperatura, respiraci??n, coloraci??n, sudoraci??n, actuaci??n correcta en crisis epil??pticas; estimulaci??n del afecto desde una perspectiva multisensorial : a trav??s de la voz, de las caricias, del abrazo; aprender a interpretar el lenguaje corporal del ni??o-a como veh??culo de comunicaci??n principal; asumir e incorporar los elementos t??cnicos-sanitarios dentro de la unidad escolar; preparaci??n del personal educativo en conocimientos b??sicos de salud y de cuidados sanitarios para dar seguridad al alumnado durante su jornada escolar; incorporaci??n de personal sanitario dentro de los centros escolares.

Tratamiento de las alteraciones del lenguaje usando como recurso el ordenador

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La pedagog??a Waldorf y el juego en el jard??n de infancia : una propuesta te??rica singular

El t??tulo aparece en espa??ol y, a continuaci??n, el t??tulo traducido al ingl??s: ???Waldorf Education and Play in the Kindergarden. An Outstanding Theoretical Proposal'