OBJECTIVETo investigate the differential value of inhaled volume and exhaled volume in anesthesia mice, and its effect on the pressure change inside of plethysmograph.

METHODSPressure and temperature in head chamber of double-chamber plethysmograph were tested when mice were placed in the body chamber. The differential values of inhaled volume and exhaled volume of mice were calculated.

RESULTThe baseline pressure in head chamber increased with temperature rising within 12 minutes, then went down though temperature remained high. The inhaled volumes of 8 mice were (0.2842 + or - 0.0173)ml,and the differential value of inhaled volume and exhaled volume was (0.0012 + or - 0.0002)ml.

CONCLUSIONThe inhaled volume is larger than exhaled volume, which makes pressure baseline of plethysmograph decreased. The differential value may be generated from respiratory quotient.

Animals ; Exhalation ; physiology ; Inhalation ; physiology ; Mice ; Plethysmography ; Pressure ; Temperature ; Tidal Volume ; Vital Capacity ; physiology

The main physiological function of respiratory system is exchange of oxygen and carbon dioxide between atmosphere and blood. Its physiological process is closely related with air flow and transport in respiratory airway. This paper studies numerically the inspiratory flows in a two generation and a three generation bronchial airway. The numerical results of the two generation bronchi show that the present computations fit the available experiments very well. For three generation bronchi, no separation appears within the whole airway under normal breathing rate, which is contrary to the occurrence of separation at even low Reynolds number by the previous two dimensional models. Strong secondary flow phenomenon, skew and m-shaped main flow velocity profiles are found in the airways due to geometrical curvature and bifurcation. These increase shear stress acting on the inner wall as well as on the anterior and posterior wall in the bifurcating airways. In the end bronchi of the three generation airway, the mass flow rates in medial and lateral bronchi are unequal, and the mass flow ratio between the medial and the lateral bronchi is 1.2 at the flow conditions considered.
Bronchi ; anatomy & histology ; physiology ; Finite Element Analysis ; Humans ; Inhalation ; physiology ; Models, Biological

Pressure-support ventilation (PSV) is a form of important ventilation mode. Patient-ventilator synchrony of pressure support ventilation can be divided into inspiration-triggered and expiration-triggered ones. Whether the ventilator can track the patient's inspiration and expiration very well or not is an important evaluating item of the performance of the ventilator. The ventilator should response to the patient's inspiration effort on time and deliver the air flow to the patient under various conditions, such as different patient's lung types and inspiration effort, etc. Similarly, the ventilator should be able to response to the patient's expiration action, and to decrease the patient lung's internal pressure rapidly. Using the Active Servo Lung (ASL5000) respiratory simulation system, we evaluated the spontaneous breathing of PSV mode on E5, Servo i and Evital XL. The following parameters, the delay time before flow to the patient starts once the trigger variable signaling the start of inspiration, the lowest inspiratory airway pressure generated prior to the initiation of PSV, etc. were measured.
Exhalation ; Humans ; Inhalation ; Interactive Ventilatory Support ; Lung ; physiology ; Pressure ; Ventilators, Mechanical

OBJECTIVETo investigate the role of histamine H1 receptors in modulating the discharge activities of the inspiratory neurons in the nucleus retrofacialis of neonatal rats.

METHODSBrainstem slices were obtained from neonatal rats containing the medial region of the nucleus retrofacialis (mNRF) with the hypoglossal nerve (XII nerve) rootlets retained. The rhythmic discharges of the inspiratory neurons (I neurons) and activities of the XII nerve rootlets were simultaneously recorded using microelectrodes and suction electrodes, respectively. The role of H1 receptors in modulation of the discharge activities of the inspiratory neurons was investigated using the H1 receptor agonist histamine and its specific antagonist pyrilamine dissolved in modified Kreb's solution for slice perfusion.

RESULTSHistamine shortened the respiratory cycle (RC) and expiratory time (TE) of the neurons in the brain slices, and pyrilamine produced the opposite effects. Neither histamine nor pyrilamine affected the inspiratory time (TI), integral amplitude (IA) or the peak discharge frequency (PF) of the I neurons.

CONCLUSIONH1 receptors play an excitatory role in the modulation of the discharge activities of the inspiratory neurons in neonatal rat brainstem slices.

Animals ; Animals, Newborn ; Electrophysiological Phenomena ; Female ; In Vitro Techniques ; Inhalation ; physiology ; Male ; Medulla Oblongata ; cytology ; physiology ; Neurons ; physiology ; Rats ; Rats, Sprague-Dawley ; Receptors, Histamine H1 ; physiology

OBJECTIVETo observe the effect of glycine on the discharge activities of inspiratory neurons in the medulla oblongata slices of neonatal rats.

METHODSNeonatal rat medulla oblongata slices including the medial region of the nucleus retrofacialis (mNRF) with the hypoglossal nerve rootlets retained were prepared. The activity of the inspiratory neurons in the mNRF and the respiratory rhythmical discharge activity (RRDA) of the hypoglossal nerve rootlets were simultaneously recorded using microelectrodes and suction electrodes, respectively. The effect of glycine on the rhythmical respiration was investigated by administration of glycine receptor agonist and its specific antagonist strychnine (STR) into a modified Kreb's perfusion solution (MKS).

RESULTSGlycine significantly shortened the inspiratory time (TI) and integral amplitude (IA) of the inspiratory neurons and decreased the peak frequency (PFn). By contrast, STR induced a decrease in the expiratory time (TE) and respiratory cycle (RC) of the inspiratory neurons, but the peak frequency was not significantly affected.

CONCLUSIONGlycine and its receptor play a role in the modulation of the rhythmical respiration, and glycine is probably involved in the phase-switching between expiration and inspiration by affecting the inspiratory neurons.

Animals ; Animals, Newborn ; Electrophysiological Phenomena ; Glycine ; pharmacology ; In Vitro Techniques ; Inhalation ; physiology ; Medulla Oblongata ; cytology ; physiology ; Neurons ; physiology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the effect of non-invasive positive pressure ventilation (NIPPV) on the work of breathing (WOB) in patients with acute exacerbation of chronic obstructive pulmonary disease (COPD).

METHODSEleven patients with acute exacerbation of COPD received pressure support ventilation (PSV) at different levels during NIPPV. The changes of inspiratory muscle effort and breathing pattern of the patients were observed.

RESULTSThe average minute ventilation (VE, P<0.01) and tidal volume (VT, P<0.05) of the patients were significantly higher during routine PSV and high pressure support (H-PS) than those during spontaneous breathing (SB), and the breathing pattern of the patients did not undergo significant changes during high positive end expiratory pressure (H-PEEP). The WOB of the inspiratory muscles was reduced significantly during PSV as compared with that measured in SB (P<0.01), while the WOB of exspiratory muscle increased significantly (P<0.01).

CONCLUSIONNIPPV can relieve the load of the inspiratory muscles in patients with acute exacerbation of COPD, and the WOB of the inspiratory muscles can be reduced by PSV, H-PEEP and H-PS (by 75%, 71% and 76%, respectively), but higher PSV during NIPPV can cause higher WOB of the exspiratory muscles.

Aged ; Exhalation ; physiology ; Humans ; Inhalation ; physiology ; Male ; Middle Aged ; Pressure ; Pulmonary Disease, Chronic Obstructive ; pathology ; physiopathology ; therapy ; Pulmonary Ventilation ; Work of Breathing ; physiology

The small airways have been neglected for many years, but interest in the topic has been rekindled with recent advances in measurement techniques to assess this region and also the ability to deliver therapeutics to the distal airways. Current levels of disease control in asthmatic patients remain poor and there are several contributory factors including; poor treatment compliance, heterogeneity of asthma phenotypes and associated comorbidities. However, the proposition that we may not be targeting all the inflammation that is present throughout the whole respiratory tree may also be an important factor. Indeed decades ago, pathologists and physiologists clearly identified the importance of small airways dysfunction in asthmatic patients. With improved inhaler technology to deliver drug to target the whole respiratory tree and more sensitive measures to assess the distal airways, we should certainly give greater consideration to treating the small airway region when seeing our asthmatic patients in clinic. The aim of this review is to address the relevance of small airways dysfunction in the daily clinical management of patients with asthma. In particular the role of small particle aerosols in the management of patients with asthma will be explored.
Adrenal Cortex Hormones ; Aerosols ; Asthma* ; Comorbidity ; Compliance ; Humans ; Inflammation ; Inhalation ; Nebulizers and Vaporizers ; Pharmacology ; Phenotype ; Physiology ; Population Characteristics

OBJECTIVETo investigate the effects of smoke inhalation injury on the phagocytic function of rat alveolar macrophages and neutrophil apoptosis.

METHODSWistar rats inflicted with smoke inhalation injury were employed in the study. Fifty-four Wistar rats were randomly divided into normal control (N, n = 6) and inhalation injury (I, n = 48) groups. Alveolar macrophages were harvested from the BALF (bronchoalveolar lavage fluid) in I group of rats at 2, 6, 12 and 24 postburn hours (PBHs) and on 2, 3, 4 and 5 postburn days (PBDs). The dynamic change in the phagocytosis of chicken erythrocytes by alveolar macrophages in vitro was observed. The positive rate of myeloperoxidase (MPO) staining of alveolar macrophages (AMs) by MPO staining method was observed, so as to indirectly reflect neutrophil apoptosis and the phagocytosis o apoptotic neutrophils by AMs. Furthermore, the dynamic change in the inflammatory cell apoptosis within BALF was monitored by flow cytometry.

RESULTS(1) he phagocytosis of chicken erythrocytes by AMs was decreased during early postburn stage (2 - 6 PBHs) but recovered after 12 PBHs. (2) The positive MPO staining of AMs was increased gradually after injury and reached top level at 24 PBHs, but decreased during 2 - 5 PBDs. (3) The apoptotic rate within BALF was around 3.02% - 12.95% and rose to peak value at 24 PBHs.

CONCLUSIONThere was increased apoptosis of inflammatory cells within BALF. The resolution process of inflammation after smoke inhalation injury involved neutrophil apoptosis and the phagocytosis of apoptotic neutrophils by AMs.

Animals ; Apoptosis ; Macrophages, Alveolar ; pathology ; physiology ; Neutrophils ; pathology ; Phagocytosis ; Rats ; Rats, Wistar ; Smoke Inhalation Injury ; pathology ; physiopathology

OBJECTIVETo study the effects of inhaled anesthetics on human sperm motility in vitro.

METHODSSperm samples were obtained from 20 healthy men by masturbation and prepared by the swim-up technique. The effects of isoflurane and sevoflurane at the clinical concentration (1.4%-5.6%) and high concentration (5.6%-84%) on human sperm motility in vitro were observed at 25 degrees C by the computer-assisted sperm analysis (CASA).

RESULTSThe sperm vitality and motility were significantly increased on 0.5-4 h exposure to isoflurane at the clinical concentration and decreased gradually at high concentration (42%-84%). The effect of isoflurane on human sperm motility and vitality at the clinical concentration was reversible when the anesthetic withdrawn. Sevoflurane had no effects on human sperm motility and vitality at either the clinical or high concentration.

CONCLUSIONIsoflurane has a reversible increasing effect at the clinical concentration and a significant decreasing effect at the high concentration on the motility and vitality of human sperm, while sevoflurane does not affect human sperm motility and vitality at either concentration.

Adult ; Anesthetics, Inhalation ; pharmacology ; Humans ; Isoflurane ; pharmacology ; Male ; Methyl Ethers ; pharmacology ; Sperm Motility ; drug effects ; Spermatozoa ; cytology ; drug effects ; physiology

Risk assessment considers the situations and characteristics of the exposure environment and host. Various physiological variables of the human body reflects the characteristics of the population that can directly influence risk exposure. Therefore, identification of exposure factors based on the Korean population is required for appropriate risk assessment. It is expected that a handbook about general exposure factors will be used by professionals in many fields as well as the risk assessors of the health department. The process of developing the exposure factors handbook for the Korean population will be introduced in this article, with a specific focus on the general exposure factors including life expectancy, body weight, surface area, inhalation rates, amount of water intake, and soil ingestion targeting the Korean population. The researchers used national databases including the Life Table and the 2005 Time Use Survey from the National Statistical Office. The anthropometric study of size in Korea used the resources provided by the Korean Agency for Technology and Standards. In addition, direct measurement and questionnaire surveys of representative samples were performed to calculate the inhalation rate, drinking water intake, and soil ingestion.
Asian Continental Ancestry Group ; Body Surface Area ; Body Weight/physiology ; Drinking Water/standards ; *Environmental Exposure ; Humans ; Inhalation/*physiology ; Life Expectancy ; Republic of Korea ; Risk Assessment ; Soil Pollutants/chemistry