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At least 685 records · Page 38Linked to original sources
PubMed2002

Effect of meditation on respiratory system, cardiovascular system and lipid profile.

In this study, respiratory functions, cardiovascular parameters and lipid profile of those practicing Raja Yoga meditation (short and long term meditators) were compared with those of nonmediators. Vital capacity, tidal volume and breath holding were significantly higher in short and long term meditators than nonmeditators. Long term mediators had significantly higher vital capacity and expiratory pressure than short term meditators. Diastolic blood pressure was significantly lower in both short and long term meditators as compared to nonmeditators. Heart rate was significantly lower in long term meditators than in short term meditators and nonmeditators. Lipid profile showed a significant lowering of serum cholesterol in short and long term meditators as compared to nonmeditators. Lipid profile of short and long term meditators was better than the profile of nonmeditators inspite of similar physical activity. This shows that Raja Yoga meditation provides significant improvements in respiratory functions, cardiovascular parameters and lipid profile.

Adult↗
PubMed1994

[Condition of the respiratory system in workers involved in carbon black production].

Carbon black is a commercial product manufactured under controlled conditions. It is not considered as a carcinogenic substance. It is even assumed that it reduces considerably carcinogenesis of substances adsorbed on its surface. The aim of the study was to present the condition of the respiratory system of workers involved in the carbon black production. The study covered the group of exposed persons (n = 118) and the control group (n = 241). The results of environmental studies indicated excess of dust MAC values at work posts. It was concluded that exposure to carbon black was harmful to health of workers employed in its production, especially in the case of a long-term exposure to dust in concentrations exceeding MACs. Chronic bronchitis and ventilation disturbances occur more frequently in persons exposed, and smoking proved to be an additional pathogenic factor affecting health of this group of workers.

Adult↗
PubMed1989

Resonance in the mechanical response of the respiratory system to high frequency jet ventilation.

Eight normal domestic pigs (Large White breed) of body weights 17 kg to 62 kg were subjected to high frequency jet ventilation (HFJV) at frequencies of 1 to 10 Hz (60-600 breaths/min). Six animals survived the study. The gain response curves and phase shift response curves obtained for these animals indicate that respiratory system resonance can be excited at HFJV frequencies. Post-mortem examinations of the nonsurvivors' lungs suggested pulmonary barotrauma. These findings and their clinical implications are discussed.

Animals↗
PubMed1995

[Role of the autonomic nervous system (adrenergic, cholinergic and nonadrenergic, noncholinergic) in regulation of respiratory system function].

There is now recognized that the autonomic innervation of airways consists of classic adrenergic and cholinergic nerves as well as of a "third" - nonadrenergic noncholinergic (NANC) - nervous system. Taking into account its complex regulatory role can be crucial for better understanding of various phenomena attributable to bronchial asthma.

Adrenergic Fibers↗
PubMed2001

Historical cohort study of US man-made vitreous fiber production workers: IV. Quantitative exposure-response analysis of the nested case-control study of respiratory system cancer.

As part of the 1992 update of an historical cohort study of 32,110 workers employed for at least 1 year in any of 10 US fiberglass manufacturing plants, a nested case-control study was done in which data on tobacco smoking were obtained for 631 male case subjects with respiratory system cancer (RSC) and 570 control subjects matched on age and year of birth. In this more extensive analysis of the nested case-control data, we provide a detailed assessment of the most prominent findings from the initial report. We expand the scope of the analysis to consider quantitative measures of exposure to respirable fibers (RFib), formaldehyde (FOR), and silica (Sil) and consider these and other exposures together in the same model. We investigate the functional form of possible exposure-response relationships between RSC risk, RFib, and FOR. In addition, we address the statistical issues of collinearity, effect modification, and potential confounding by coexposures. All analyses are adjusted for smoking. Neither measure of exposure to RFib (average intensity of exposure or cumulative exposure) was statistically significantly associated with RSC risk in any of the hundreds of fractional polynomial models considered. This more extensive analysis has substantiated our initial finding of no apparent exposure-response relationship between RSC risk and either cumulative or average intensity of exposure to RFib at the levels experienced by these workers. This study provides some evidence of increased RSC risk among workers at the higher observed levels of average intensity of exposure to FOR and/or Sil. No positive associations were identified between RSC risk and any of the other exposures considered in this case-control study.

Adult↗
PubMed1967

Effects of oxygen and heme on the development of a microbial respiratory system.

The effect of adding hemin to anaerobically grown cells of a strain of Staphylococcus epidermidis, which was heme-deficient due to anaerobic growth, has been examined. Cells grown anaerobically in media containing hemin exhibited a marked increase in several oxidative activities as compared with cells grown anaerobically without hemin. The respiratory activity of whole cells and a cyamide-sensitive reduced nicotinamide adenine dinucleotide oxidase activity of cell-free extracts were increased fourfold. The content of enzymatically reducible pigments which exhibit difference spectra similar to cytochromes b(1) and o was also markedly increased. These pigments are mostly sedimented at 100,000 x g (1 hr). Hemin also caused a marked increase in respiratory activity when added directly to the anaerobic culture after the period of growth, but did not cause a similar increase in respiration when added to washed, resting-cell suspensions. Under the latter conditions, heme pigments were formed which exhibited difference spectra similar to, but not identical with, the spectra of pigments found in anaerobic cells grown in the presence of hemin. When resting suspensions of cells grown anaerobically without hemin were exposed to air, a rapid fourfold increase in respiratory activity and a limited increase in cytochrome-like pigments occurred. The presence of the heme precursor Delta-aminolevulinic acid during this aeration resulted in a rapid and marked increase in heme pigments, but only a slight stimulation of respiratory activity. The possible implications of these results for the roles which heme and oxygen play in the development of the respiratory system of this organism are discussed.

Cytochromes↗
PubMed1984

[A histochemical study of the respiratory system in rabbit ovarian follicles during ovulation].

Histochemical studies on the activities of 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD), succinate dehydrogenase (SDH) and cytochrome oxidase (CY-O) in rabbit ovarian follicles at various times after the administration of hCG were performed to investigate the relationship between the activities of steroid biosynthesis and the respiratory system. The activities of 3 beta-HSD and SDH were studied by using the tetrazolium salt and CY-O activities by the method of Seligman with prefixation. On the granulosa cell layer prior to the administration of hCG, no activities of 3 beta-HSD and CY-O were detectable, while slight activities of SDH were observed. These three enzymes showed intense activities on the granulosa cell layer 3 hours after the administration of hCG, which were maintained till the time of ovulation. The results indicated that increased activities of steroid biosynthesis in the granulosa cell layer after LH-surge were accompanied by the accelerated TCA cycle and respiratory chain. Energy from accelerated glycolysis may be utilized for steroid biosynthesis in preovulatory granulosa cells. Increased O2 consumption due to accelerated aerobic glycolysis is in accordance with hyperactivity of perifollicular capillaries, which finally leads to rapid follicular expansion and ovulation.

Animals↗
PubMed2003

Frequency dependence of respiratory system mechanics during induced constriction in a murine model of asthma.

Airway dysfunction in asthma is characterized by hyperresponsiveness, heterogeneously narrowed airways, and closure of airways. To test the hypothesis that airway constriction in ovalbumin (OVA)-sensitized OVA-intranasally challenged (OVA/OVA) mice produces mechanical responses that are similar to those reported in asthmatic subjects, respiratory system resistance (Rrs) and elastance (Edyn,rs) spectra were obtained in OVA/OVA and control mice during intravenous methacholine (MCh) infusions. In control mice, MCh at 1,700 microg x kg(-1) x min(-1) produced 1) a 495 and 928% increase of Rrs at 0.5 Hz and 19.75 Hz, respectively, 2) a 33% rise in Edyn,rs at 0.5 Hz, and 3) a mild frequency (f)-dependent increase of Edyn,rs. The same MCh dose in OVA/OVA mice produced 1) elevations of Rrs at 0.5 Hz and 19.75 Hz of 1,792 and 774%, respectively, 2) a 390% rise in Edyn,rs at 0.5 Hz, and 3) marked f-dependent increases of Edyn,rs. During constriction, the f dependence of mechanics in control mice was consistent with homogeneous airway narrowing; however, in OVA/OVA mice, f dependence was characteristic of heterogeneously narrowed airways, closure of airways, and airway shunting. These mechanisms amplify the pulmonary mechanical responses to constrictor stimuli at physiological breathing rates and have important roles in the pathophysiology of human asthma.

Airway Resistance↗
PubMed1990

Compliance of the respiratory system in infants born at high altitude.

Populations living at high altitude are known to have a number of distinctive physiologic traits, including an increase in lung volume and compliance. We asked whether the factors that result in the increased compliance of high altitude natives were sufficiently expressed in utero that an increase in respiratory system compliance (Crs) could be detected at birth. Measurements were performed at about 1 day after birth on 34 infants born in La Paz, Bolivia (3,600 m, Pb about 495 mm Hg) and 36 born in Santa Cruz (400 m, Pb about 735 mm Hg). All infants were full-term and healthy, with body weights of at least 2,700 g. We measured Crs from expirations within the tidal volume range by the multiple occlusion method. Breathing pattern was measured from the spirometric record, and an index of chest wall distortion was obtained from the ratio of volume and abdominal displacement during spontaneous breathing and relaxations against closed airways. Rib cage and abdomen dimensions did not differ between the two groups. Crs values in Santa Cruz were similar to those previously obtained in Montreal and in other Caucasian infant populations at low altitudes. Crs was 33% and Crs/kg 37% greater (p less than 0.001) in the high altitude group, which included equal numbers of Amerindians and Mestizos of European ancestry. Dynamic elevation of the end-expiratory level was similar in both groups. Ventilation/kg and the distortion ratio were slightly yet significantly higher in the high altitude infants, suggesting an increased ventilatory drive.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1998

Respiratory system response to ambient air magnesite particulates.

Ambient air particulates derived from a magnesite-processing plant contain magnesium oxide (85-90%), iron oxide (7-8%), calcium oxide (about 2.5-3%), Al- and Si oxides (0.1-0.5%) as well as additional elements in trace amounts as follows: Ni, Cr, Mn, Co, Hg, Cd, Pb, V, Ba, Ag, Cu and Sn. Magnesite clinker is manufactured from raw magnesite by baking in rotary furnaces using the Leseps-Polysius system, which represents the source of particulate pollutants entering the atmosphere. In the area heavily polluted by magnesite particles, the health impact using the data obtained from the exposed humans and animals was assessed. The reason for this study were the data on the increased frequency of respiratory diseases in children in the polluted area. In a group of children (9-10 years of age) residing in the area, the immune response to ambient air pollutants exposure in comparison to a non-exposed group living outside the polluted area was investigated. A statistically significant decrease in the amount of salivary lysozyme, SlgA, IgG and albumin in the exposed group was observed. Simultaneously, a 6-month respiratory exposure of a group of Chinchilla rabbits in that polluted area aimed at the simulation of the human exposure was conducted. In the exposed rabbits, enormously increased number of pulmonary alveolar macrophages (PAM) has been found. Using atomic absorption spectrometry, a statistically significant increase in magnesium content (e.g. a bioindicator of the exposure) in the body tissues of the exposed animals was found. The laboratory data obtained from the animal study contributed to the elucidation of the depressed immunity (especially in the respiratory system) in the children exposed to ambient air magnesite particulates.

Air Pollutants↗
PubMed1990

Passive expiratory flow-volume recordings in immature newborn rabbits. Effect of surfactant replacement on the time constant of the respiratory system.

Immature newborn rabbits with a gestational age of 27 days were paralyzed and kept in body plethysmographs. They were ventilated for 10 min with a tidal volume of approximately 10 ml/kg, with or without previous surfactant treatment via the airways. Tidal volumes and flow were recorded with a pneumotachograph connected to the body plethysmograph, and the expiratory time constant of the respiratory system (trs) was determined from flow-volume diagrams. The values of trs after 10 min were significantly higher in surfactant-treated animals than in controls (50 +/- 7 vs. 23 +/- 4 ms; p less than 0.002), indicating stabilization of the alveoli. There was also a close correlation between trs and the compliance values calculated from tidal volumes and ventilator pressure (r = 0.80; p less than 0.001), as well as between trs and the alveolar volume density in histological lung sections, determined by automated image analysis (r = 0.71; p less than 0.001).

Animals↗
PubMed1991

[Functional state of the respiratory system in the handicapped after amputation of the upper limbs].

There are given the results of study of external respiration function of 45 invalids after amputation of upper limbs, including 20 after amputation of one arm and 25 after amputation of both arms. The study was carried out at rest and with physical loading at veloergometer. Detected disturbances of external respiration function are determined by decrease of reserve capability of respiratory system due to disturbance of dynamic balance of muscular system of shoulder girdle and thorax, muscle atrophy, thorax excursion decrease. There are given recommended locomotory regimens and allowable physical loads and recommendations concerning prosthetics and exercise therapy.

Adult↗
PubMed1975

Effective respiratory system elastance during positive-pressure breathing in supine man.

Two healthy males relaxing supine on a ballistobed were mechanically ventilated at positive end-expiratory pressures (PEEP) from 0 to 19 cmH2O. Pressures at the airway opening, middle esophagus, and stomach were monitored, together with tidal volume (VT) and ballistobed displacement. The effective elastance (i.e., sum of active and passive components) of the respiratory system (E'rs) and its components--abdominal muscle (E'ab), diaphragm (E'di), and rib cage (E'rc)--were calculated. With increasing PEEP, lung compliance increased slightly, E'rc and E'di decreased linearly, and E'ab increased linearly. The combined effective elastance of abdomen and diaphragm (E'ab+di) first decreased and then increased again. The abdomen-diaphragm contribution to VT during mechanical ventilation was approximately half that of spontaneous breathing.

Abdomen↗
PubMed2000

Interrelation between oxygen tension and nitric oxide in the respiratory system.

To understand the relationship between oxygen tension and nitric oxide (NO) function, one animal and two human studies were designed. In the animal study, the effect of NO in inducing the relaxation of aortic specimens was significantly lower by 68% under 480 mm Hg of oxygen tension than under 28 mm Hg, indicating that oxygen tension has an important role in determining the biological effects of NO. In a clinical analysis with nonsmokers (n = 23), the alveolar-to-arterial difference for oxygen (A-aDO(2)) was reciprocally correlated with exhaled NO concentrations (r = 0.53). Because NO concentration in the lower respiratory zone depends partly on the amount of inspirable NO originating in the upper airway, a well-ventilated area, requiring much perfusion, could receive greater amounts of NO than a poorly ventilated one. Thus, the reciprocal relation of A-aDO(2) with the concentration of exhaled NO is not necessarily incompatible with the effect of hypoxic pulmonary vasoconstriction in ventilation-to-perfusion (V'A/Q') imbalance. In our third experiment, with nonsmokers (n = 21), pure oxygen inhalation during mechanical ventilation significantly decreased the concentration of exhaled NO and enhanced A-aDO(2), indicating a relationship between NO and oxygen similar to that observed in the animal experiment. These findings led us to conclude that a positive relation between exhaled NO and blood oxygenation efficiency exists in the respiratory system, and further, that oxygen might affect this relationship. Thus, the relative balance of NO and oxygen concentrations may be another factor for consideration in respiratory function.

Adult↗
PubMed1995

[Forced oscillation technique in respiratory system studies. III. Compliance and airway resistance in children with lung fibrosis].

In patient with lung fibrosis we need to monitor lung compliance to evaluate the progress of the illness or efficacy of the treatment. This examination is not well tolerated and difficult to perform, especially in children. We compared classic measurements of static compliance of the lung and airway resistance with parameters derived from forced oscillations measurements--compliance and resistance of respiratory system. Correlation coefficients were respectively 0.85 for compliance and 0.70 for resistance. We conclude that it is possible to supplement classic measurements, especially in evaluating the dynamics of illness.

Adolescent↗