Assessment of Benchmark Dose in BEAS-2B Cells by Evaluating the Cell Relative Viability with Particulates in Motorcycle Exhaust / 生物医学与环境科学（英文）

Objective@#This study aimed to use an air-liquid interface (ALI) exposure system to simulate the inhalation exposure of motorcycle exhaust particulates (MEPs) and then investigate the benchmark dose (BMD) of MEPs by evaluating cell relative viability (CRV) in lung epithelial BEAS-2B cells.@*Methods@#The MEPs dose was characterized by measuring the number concentration (NC), surface area concentration (SAC), and mass concentration (MC). BEAS-2B cells were exposed to MEPs at different concentrations @*Results@#Our results reveal that BMD of NC and SAC were estimated by the best-fitting Hill model, while MC was estimated by Polynomial model. The BMDL for CRV following ALI exposure to MEPs were as follows: 364.2#/cm @*Conclusion@#These results indicate that MEPs exposure

Evaluación funcional de la vía aérea / Functional asessment of airway

Airway function study includes a variety of tests involving various sub-specialties of medicine and related professions. We describe the methods that assess: 1) upper airway (nose to larynx): rhinomanometry, acoustic rhinometry and nasopharingolaryngoscopy, 2) central airways (trachea and main bronchi): bronchoscopy, imaging study and Flow / Volume curve, 3) distal or peripheral airway: spirometry, bronchodilator response assessment, airway hyper responsiveness and measurement of airway resistance (plethysmography, interrupted resistence and impulse oscillometry).

El estudio de la función de la vía aérea abarca una gran variedad de exámenes que implican a diversas subespecialidades de la medicina y profesiones relacionadas. Se describen los métodos que evalúan: 1) vía aérea superior (nariz hasta laringe): rinomanometría, rinometría acústica y nasofarigolaringoscopía, 2) vía aérea central (tráquea y bronquios mayores): bronconcoscopia, estudio de imágenes y curva flujo/volumen, 3) vía aérea distalo periférica: espirometría, evaluación de respuesta a broncodilatador y de hiperreactividad bronquial y medición de la resistencia de la vía aérea (pletismografía, resistencia interrumpida y oscilometría de impulso).

Pharmacologic bronchodilation response to salbutamol in COPD patients.

Background: Airway hyperresponsiveness (AHR) is the most characteristic feature of asthma, which is reported in COPD patients and smokers. Increased airway responsiveness to ί-agonists is also demonstrated in asthmatics as well as smokers. However, there is no report regarding AHR to ί-agonist drugs in COPD patients. Therefore, in this study pharmacologic bronchodilation response to salbutamol in COPD patients was examined. Materials and Methods: The threshold concentrations of inhaled salbutamol required for a 20% change in forced expiratory flow in 1 sec (FEV 1 ) as PC 20 , or a 35% change in specific airway conductance (sGaw) as PC 35 was measured in 14 COPD patients and 14 normal subjects. Results: Airway responsiveness to salbutamol in COPD patients (PC 20 = 14.14 ± 1.62 and PC 35 = 9.70 ± 1.48 mg/l) was significantly lower than normal subjects (PC 20 = 224.57 ± 16.62 and PC 35 = 81.87 ± 8.16 mg/l, P < 0.001 for both cases). The values of FEV 1 and sGaw in COPD patients (56.43 ± 14.45 and 0.081 ± 0.120 respectively) were significantly lower than those of normal subjects (104.07 ± 5.72 and 0.194 ± 0.041 respectively), (P < 0.001 for FEV 1 and P < 0.005 for sGaw). There was a significant correlation between FEV 1 with PC 20 salbutamol (r = 0.862, P < 0.001). The correlations between PC 20 and PC 35 was also statistically significant (r = 0.862, P < 0.001). Conclusion: These results showed increased airway responsiveness of most COPD patients to salbutamol which was highly correlated to airway caliber.

Detection of bronchial function of NHBD lung following one-h warm ischemia by organ bath model / 华中科技大学学报（医学）（英德文版）

This study investigated the feasibility and effects of organ bath to be used for detection of bronchial function of non-heart-beating donor (NHBD) lung after 1-h warm ischemia. Sixteen Swedish pigs were divided into two groups randomly: heart-beating donor (HBD) group and NHBD with 1-h warm ischemia (NHBD-1 h) group. The bronchial rings whose lengths and inner diameters were both 1.5 mm were obtained from isolated left lungs of all the pigs. Acetylcholine, arachidonic acid natrium and papaverine were used to test and compare the contractile and relaxant function of bronchial smooth muscles and epithelium-dependent relaxation (EpiDR) response between HBD and NHBD-1 h groups. The results showed that there was no significant difference in the values of bronchial precontraction between HBD and NHBD-1 h groups (5.18+/-0.07 vs 5.10+/-0.11 mN, P>0.05). No significant difference in the values of EpiDR responses between HBD and NHBD-1 h groups (1.26+/-0.05 vs 1.23+/-0.07 mN, P>0.05) was observed either. During the process of EpiDR induction, the rings had no spontaneous relaxation in two groups. In addition, papaverine solution completely relaxed the bronchial smooth muscles of all bronchial rings. It was concluded that after warm ischemia for 1 h, the contractile and relaxant abilities of bronchial smooth muscles, and the epithelium-dependent adjustment both kept intact. Organ bath model could be a liable and scientific way to evaluate the bronchial function of NHBD lung.

Ontogenic changes in the fractal geometry of the bronchial tree in Rattus norvegicus

Respiration and metabolism change dramatically over the course of the development of vertebrates. In mammals these changes may be ascribed to organogenesis and differentiation of structures involved in gas exchange and transport and the increase in size. Since young as well as mature individuals must be well-designed if the species is to survive, the physiological changes during the development should be matched with geometrical or structural adjustments of the respiratory system. The aim of this study was to evaluate changes in the fractal geometry of the bronchial tree during the postnatal development of the rat. The average fractal dimension of the bronchial tree of the rats was 1.587, but that of juveniles was larger than that of the adults. We found a significant negative correlation between age and fractal dimension. This correlation could be considered be misleading because of the difficulty of separating age/body size effects. Nevertheless, because fractal dimensions of the bronchial tree of rabbits and humans are known to be similar, 1.58 and 1.57 respectively, the body size effect may be nil. To our knowledge, this is the first report of ontogenetic changes in the fractal dimension of the bronchial tree in mammals.

La reactividad de la musculatura bronquial en sujetos jóvenes: patrones en condiciones normales / Bronchial muscle reactivity in young healthy individuals: the pattern in normal conditions

Se analizan críticamente el método presentado en un trabajo anterior en el que se explora, de una manera sencilla, en el hombre, la reactividad de la musculatura de los broquios. Se presentan los resultados obtenidos con este método en 35 sujetos jóvenes sanos. El propósito fue el de encontrar valores que pudieron ser considerados como representativos de los patrones normales para individuos sanos, los cuales podrían servir de base para su comparación con los que se obtengan en los estudios de caso patológicos. Se discute la posibilidad de que la medida de la circunferencia torácica no presente un cambio proporcional de la capacidad pulmonar. Se presentan los resultados de los controles realizados en apoyo de este postulado, uno de los que sirvieron de base para la justificación del método. Se confirma que el músculo liso de los bronquios se encuentra en estado dinámico en las condiciones fisiológicas y que participa en la actividad refleja del sistema nervioso autónomo y en los estados emocionales. Se compara la actividad de este tipo de músculo con la de otros efectos autonómicos

Caracterización de la geometría fractal del árbol bronquial en mamíferos / Measuring the fractal geometry of the bronchial tree in mammals

El árbol bronquial de los mamíferos presenta un diseño que se ha asociado con un adecuado flujo de gases a los alvéolos, una mínima producción de entropía en la mecánica respiratoria y con un mínimo costo en materia y energía. Sin embargo, la vía aérea constituye sólo parte del sistema respiratorio y como tal su geometría debe ajustarse a la función de todo el sistema resolviendo el problema de distribuir un volumen de aire inspirado en una gran superficie, dispuesta en un volumen acotado. Así, la topología bronquial exhibe las características de ocupar espacio con su ramificación progresiva y una reducción del diámetro de los bronquios que se ha asociado a una geometría fractal. En este trabajo se caracteriza la topología del árbol bronquial de Rattus norvegicus mediante su dimensión fractal y se compara con otros mamíferos de distinto tamaño: Oryctolagus cuniculli y Homo sapiens. Se estudia además el efecto de la escala para verificar la autosimilitud. Los resultados demuestran una geometría fractal de la vía aérea de las tres especies, que se mantiene a distintas escalas y son una demostración directa de este tipo de geometría. La topología se mantiene invariante en las tres especies, con dimensiones fractales entre 1,57 y 1,59. Los resultados coinciden con otros estudios realizados en la vía aérea, la superficie alveolar, la ventilación y la perfusión pulmonar. Se discuten las consecuencias de este tipo de geometría en el pulmón

Método no invasivo para explorar la actividad de la musculatura bronquial. valoración de la resistencia de las vías aéreas / Non-invasive trial for the assessment of the brinchial musculature. An evaluation of the airway resistance

Se presenta un método sencillo para explorar las funciones de la musculatura bronquial en el hombre. Fueron empleados individuos sanos voluntarios y algunos pacientes neumológicos. La respiración fue registrada con un neumógrafo colocado en la base del tórax y el flujo de aire con un neumotacógrafo de Fleisch acoplado a una mascarilla ordinaria. Se midió la amplitud máxima de los trazos: en condiciones de reposo; durante y después de una inspiración profunda, de un periodo breve de apnea voluntaria, de la maniobra de Valsalva, o de la aplicación de un ruido súbito. Con las medidas se estableció la relación P/V (presión intra-torácica/volumen pulmonar) se graficaron los datos obtenidos. Se encontró que la musculatura bronquial cambia en su resitencia al flujo de aire, tanto en las condiciones de control como en las manifestaciones reflejas evocadas por las maniobras experimentales empleadas y los estados emocionales, siguiendo las reacciones del sistema nervioso autónomo. Se concluye que a pesar de los diversos factores de error, el método puede ser muy útil para explorar la reactividad del músculo liso de los bronquios en situaciones normales y eventualmente en algunas patológicas

Traqueobronquite necrotisante: relato de um caso em lactente / Necrotizing tracheobronchitis in an infant

Objetivo: Alertar os pediatras emergencistas para uma causa pouco comum de obstruçäo de vias aéreas em crianças submetidas a ventilaçäo mecânica. Métodos: Os autores relatam um caso de traqueobronquite necrotisante em lactente de 8 meses e discutem a fisiopatologia, diagnóstico e abordagem terapêutica. Resultados: A crianca apresentou evoluçäo favorável associado ao diagnóstico precoce e pronta intervençäo broncoscópica. Conclusöes: Os pediatras emergencistas devem suspeitar de traqueobronquite necrotisante em todas as crianças sob ventilaçäo mecânica que apresentarem o quadro clínico típico caracterizado por obstruçäo aguda das vias aéreas, hiperinsuflaçäo pulmonar, mesmo fora do período neonatal. Essa situaçäo, uma vez reconhecida, constitui indicaçäo precisa de traqueobroncoscopia de urgência...

Efeitos da poluiçäo, tabagismo e poeiras minerais sobre o aparelho respiratório / Effects of pollution, smoking and mineral dusts on respiratory system

Doenças pulmonares intersticiais difusas e doenças crônicas das vias aéreas podem ser causadas por poeiras minerais, poluiçäo e fumo e säo discutidas neste trabalho. Doenças pulmonares ocupacionais e ambientais constituem assunto amplo e complexo, impossível de ser abordado em sua íntegra em um simples trabalho, de modo que daremos destaque a conceitos básicos envolvendo mecanismos de defesa pulmonar e um pouco da experiência prática na rotina diagnóstica. Nos pulmöes, doenças intersticiais ocupacionais säo o resultado final da composiçäo de lesöes focais. Esses sítios de lesöes focais traduzem a resposta do tecido pulmonar alveolado e condutor ao fumo, particulas ou minerais. Com a injúria pulmonar crescente e repetitiva, inflamaçäo e fibrose determinam distorçäo e remodelaçäo pulmonar, finalmente conduzindo a alteraçöes da fisiologia respiratória. Nos alvéolos, o macrófago pulmonar parece ter um papel central no desenrolar desses eventos, agindo tanto como fagócito incorporador de particulas quanto como mediador liberador de poderosas substâncias biológicas modificadoras da funçäo de outras células, como neutrófilos e fibroblastos

Exercise induced bronchial lability in normal men and women--a comparison.

Normal male (n = 29) and female (n = 39) medical students with a mean age of 19.2 years who were nonsmokers, with no personal history of allergy were studied. The bronchial lability was assessed from peak expiratory flows and forced expiratory spirograms taken before, during and upto 45 minutes after a standard exercise using the Harvard steps. Women had a significantly lower (P < .001) resting FVC, FEV1, FEF 25-75% and PEF as compared to men. Although the exercise lability index was not significantly different in men and women, the latter showed a greater percent increase (P < .02) and a lesser percent decrease (P < .02) of PEF during and after the exercise respectively. They also showed a significantly (P < .005) faster recovery to normal. These results suggest that airway dynamics may be better in women than in men. This could account for the lower incidence and morbidity from respiratory allergic disease seen in women as compared to men.

Potassium channel opening drugs and the airways

1. Potassium channel opening drugs (KCOs) include benzopyrans such as cromakalim, cyanoguanidines such as pinacidil and tetrahydrothiopyrans such as RP 49356. 2. While clinical trials have indicated that cromakalim may be of benefit in the treatment of nocturnal asthma, it remains to be determined whether KCOs will find a place in our armamentarium of clinically useful anti-asthma agents. 3. KCOs inhibit the spontaneous tone of airways smooth muscle in vitro, an action associated with membrane hyperpolarization towards the potassium equilibrium potential and with the promotion of 86Rb+ or 42K+ efflux from the muscle cells. KCOs suppress spasm of airways smooth muscle evoked by low (< 40 mM) but not high (> 40 mM) concentrations of KCl. Their relaxant effects in airways smooth muscle can be attenuated by a variety of agents (including sulphonylureas) known to inhibit the opening of plasmalemmal K(+)-channels. 4. The KCOs open an ATP-sensitive K(+)-channel (KATP) in the plasmalemma. KATP is not open under normal circumstances and does not play an important role in determining the strong outward rectifying behavior of the cell membrane. The biochemical mechanisms by which the KCOs promote the opening of KATP remain to be elucidated but probably do not involve channel phosphorylation consequent to the intracellular accumulation of cAMP. 5. By causing hyperpolarization of the plasmalemma, the KCOs inhibit the cellular influx of Ca2+ through voltage-dependent channels. Relaxation follows both as a direct consequence of the fall in cytosolic free Ca2+ and also as a consequence of reduced production of phosphoinositide second messengers. The KCOs may also inhibit Ca2+ uptake by, and hence Ca2+ release from, the sarcoplasmic reticulum. 6. KCOs can inhibit cholinergic and non-adrenergic, non-cholinergic (NANC) excitatory neuroeffector transmission in the airways by glibenclamide-sensitive mechanisms which may involve inhibition of neurotransmitter release. The KCOs do not attenuate NANC inhibitory neuroeffector transmission, suggesting that KATP may not be expressed in neurones of this type. 7. The active enantiomer of cromakalim has been found to be effective in alleviating nocturnal asthma at plasma concentrations just threshold for relaxing human airways smooth muscle in vitro. The clinical efficacy of cromakalim may therefore depend on an action other than the direct relaxation of airways smooth muscle. Animal studies indicate that KCOs can reduce airway hyper-reactivity at sub-bronchodilator doses. The mechanism of this effect remains to be elucidated and may not crucially depend upon inhibition of neurotransmitter release within the lung

Immediate effect of tobacco chewing in the form of 'paan' on certain cardio-respiratory parameters.

Immediate effect of tobacco in the form of chewing was evaluated in 40 healthy males (mean age 26.27 yrs.) not habituated to tobacco, who were given paan containing 200 mg of tobacco to chew (group T). Heart rate (HR), blood pressure (BP), forced vital capacity (FVC), FEV1 and peak expiratory flow rate (PEFR) were measured twice for each subject, once before chewing and again immediately after completion of chewing. Another 24 age and sex matched controls (group C) were given paan without tobacco to chew and cardiorespiratory parameters were recorded as for group T subjects. Electrocardiography was recorded in 10 group T and 10 group C subjects. Effect of tobacco chewing was also evaluated in 10 habitual tobacco chewers. Results showed statistically significant increments in HR and BP as well as a decline in T wave amplitude in ECG following tobacco chewing (group T subjects). The changes in HR and BP lasted for 15-30 mins, as observed in 10 of group T subjects. The FVC, FEV1 and PEFR showed marginal, though non-significant, increments after tobacco chewing. No significant difference in the cardiorespiratory responses to tobacco chewing could be seen between habitual and nonhabitual (group T) tobacco chewers. The changes in cardiovascular and respiratory parameters following paan (without tobacco) chewing in the control subjects were negligible and nonsignificant.