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PubMed1983

Review of experimental studies on the functional development of the respiratory system in the foetal lamb.

In the foetus, as in the adult, the behavioural state of the central nervous system plays a very significant role in the modulation of respiratory activity. Breathing at birth represents the continuation of a process that commences early in life in utero and develops as gestation proceeds. The profile of classical afferent respiratory input to the foetus in utero is significantly different to that of the new born, with a reduction in total neural traffic and a smaller phasic variation. The foetus, however, phasically contracts its diaphragm which, as gestation proceeds, is patterned into distinct 'on and off' periods. Breathing of the foetus occurs during rapid eye movement sleep, analogous to that in the adult, and continues following somatic stimulation. This behavioural state is reduced during foetal hypoxia and foetal respiration is simultaneously depressed. At birth there is an increase in both somatosensory neural input and phasic variation and the new born breathes in all behavioural states, the stability of which varies cyclically with a period similar to that seen before birth. Whereas improved surgical and experimental techniques and non-invasive technology have enabled a more complete description of the development of the respiratory system in utero, the transitional events of the processes which occur at birth happen very quickly and at present prevent a similar detailed description.

Animals↗
PubMed1982

Function of the future respiratory system in the growth retarded fetal sheep.

The development of the future air breathing respiratory system was investigated in eight carunclectomised fetal sheep and five control fetal animals over the last third of gestation (approximately day 100-day 145). Carunclectomy resulted in the test fetal animals being hypoxaemic, hypercapnic, hypoglycaemic and acidotic. All fetal animals were chronically instrumented with diaphragmatic electromyographic leads, fetal jugular vein and carotid artery catheters, an amniotic fluid catheter and small electrocardiographic leads placed on the chest wall. There was evidence of a significant, but small, reduced relative lung size in the carunclectomised animals by day 140 without corresponding relative changes in the weight of the brain, liver, or heart. Diaphragmatic electromyograph (EMG) was analysed in detail over the last third of gestation. In both groups of animals, the normal reduction in fetal 'breathing' rate, and the normal increase in fetal apnoea was noted with increasing periods of diaphragmatic silence as fetal apnoea was noted with increasing periods of diaphragmatic silence as gestation advanced. Linear regression analyses revealed that fetal breathing rate was significantly reduced over the last third of gestation, whilst fetal apnoea significantly increased in the carunclectomised animals. Average total integrated diaphragmatic activity was reduced prior to 120 days. This reduction was evident in the strength of each diaphragmatic contraction before 110 days. In three test and three control animals, histochemical analyses were undertaken to fibre type the muscles of the diaphragm. Fatigue resistant fibres were significantly reduced in the carunclectomised fetuses, and fibre diameters were diminished. Centroid analyses of the power spectrum of the diaphragmatic EMG did not however support the concept of increased muscle fatigue in the test animals.

Animals↗
PubMed1986

Freezing injury in the yeast respiratory system.

The effect of freeze-thawing on the yeast respiratory system was studied at rapid rates of cooling. Freezing of whole cells with liquid nitrogen induced decrease of respiratory activity to under 20% of that of original cells. Mitochondria harvested from freeze-thawed cells have markedly decreased succinate oxidizing activity. Activity of succinate cytochrome c reductase was reduced significantly after freeze-thawing of whole cells while activities of succinate dehydrogenase and cytochrome c oxidase were reduced slightly. By spectrophotometric analysis it was found that about one-half the amount of cytochrome c + c1 was eluted from mitochondria to cytosol after freeze-thawing of cells. The activities of succinate oxidation in mitochondria from freeze-thawed cells were restored to normal levels by the addition of cytochrome c. Freeze-thawing of isolated mitochondria did not induce deactivation of succinate oxidizing activities and succinate cytochrome c reductase, and no elution of cytochrome c was observed. It was concluded that the decreased respiratory activities of yeast cells by freezing of cells with liquid nitrogen can be attributed primarily to the elution of cytochrome c from mitochondria.

Cell Fractionation↗
PubMed1995

The respiratory system in a cold environment.

Acute or chronic cold exposure elicits several effects on the respiratory system. Pulmonary mechanics are compromised by bronchoconstriction, airway congestion, secretions and decreased mucociliary clearance. These responses are active in cold- or exercise-induced asthma, and are possibly responsible for decreased immune function and protection against airborne pollutants. The primary ventilatory effect of cold air is to decrease baseline ventilation and respiratory chemosensitivity. Although these responses provide significant protection against heat loss in many animals, the effect in humans is minimal. Cold exposure also elicits an increase in pulmonary vascular resistance. This stimulus is synergistic with hypoxia and may mediate pulmonary hypertension and edema at altitude. Chronic exposure to cold environments results in morphological changes such as increased numbers of goblet cells and mucous glands, hypertrophy of airway muscular fascicles and increased muscle layers of terminal arteries and arterioles. These latter two factors may play a role in the symptoms of chronic obstructive pulmonary disease and bronchitis, high altitude pulmonary hypertension and edema, and right heart hypertrophy.

Acute Disease↗
PubMed1996

[Respiratory system function in workers from the Mechanical Petrochemical Plant in Płock--influence of the workplace environment].

UNLABELLED: The aim of this study was to evaluate the influence of the work place environment on the function of the respiratory system. MATERIAL: Study covered 211 male from Mechanical Plant of Plock Refinery (M.P. group 1) and the control group consisted of 53 male employed in Design Office (D.O. Group II). Group I was exposed to toxic substances (NO2, SO2, dust, manganese and iron oxides). METHODS: Lung function tests were performed using laboratory "Compact-Lab" (JAEGER). The FVC, FEV1, FEV1%FVC, PEF, FEF50 were obtained from flow-volume curve and TGV, Rt measured using plethysmography method. Information concerning symptoms and cigarette smoking were obtained from questionnaire designed for this study. RESULTS: Mean values of respiratory indices were within normal range and did not differ between groups. The percentage of abnormal results was similar in groups. Air flow limitation (FEV1%FVC < 70%) was observed in 15.2% of total. Smokers have had significantly lower indies of air flow limitation but still within normal range. Symptoms (cough, expectoration, dyspnea) were equally frequent in M.P. and D.O. and significantly more frequent in smokers. CONCLUSION: In our study we did not find the influence of work place environment on the function of the respiratory system.

Adult↗
PubMed2002

[Dynamics of the human respiratory system parameters at different rates of +Gz load rise].

Studies of the dynamics of human respiratory system parameters during 15-s runs with +Gz loads from 6 to 9 units and rates of rise equal to 1, 2, 3 and 5 units/s showed that increase in the rate of rise produced specific shifts in the breathing cycle structure which characterize the voluntary adaptation of humans to g-loads. Results also make it evident that despite absence of difference in the respiratory reactions during +Gz runs, in the period following exposure the distinct increases in the parameters of external breathing and gas-energy exchange correlated with the rate of g-rise. This allows the conclusion that because of the reasons discussed in the paper the physiological cost of Gz-tolerance grows as the rate of g-rise gets high.

Adaptation, Physiological↗
PubMed2006

[Long-term impact of transfer of phrenic nerve on respiratory system of children: a clinical study of 34 cases].

OBJECTIVE: To study the long-term impact of transfer of phrenic nerve on respiratory system of children. METHODS: Thirty-four children with brachial plexus injury, 25 boys and 9 girls, underwent transfer of phrenic nerve and were divided into 3 groups according to the age when they underwent operation: group of the age of 0 - 12 months (n = 17), group of 13 - 36 months (n = 11), and group of 37 - 60 months (n = 6). Thirty-four sex, height, and body weight-matched healthy children were used as controls. Follow-up, including physical examination, pulmonary function examination (tidal volume, ventilation, etc), blood gas analysis, and chest radiography, was conducted for 4.03 years (3 - 7 years). RESULTS: The values of maximum vital capacity of the group of 0 - 12 months and group of 13 - 36 months were 1.0 L +/- 0.2 L and 1.2 L +/- 0.4 L, both significantly lower than those of the corresponding control groups (1.3 L +/- 0.3 L and 1.4 L +/- 0.5 L, both P < 0.05). The values of one-second vital capacity of the group of 0 - 12 months and group of 13 - 36 months were 0.8 L +/- 0.1 L and 0.9 L +/- 0.1 L, both significantly lower than those of the corresponding control groups (1.0 L +/- 0.1 L and 1.0 L +/- 0.1 L, both P < 0.05). However, the values of the maximum vital capacity and one-second vital capacity of the group of 37 - 60 months were 1.6 L +/- 0.3 L and 1.8 L +/- 0.5 L respectively, both not significantly different from those of the controls (both P > 0.05). The results of blood gas analysis of the 3 operation groups were not significantly different from those of the corresponding controls. Chest radiograph showed that the diaphragm top was raised by 1.93 intercostal spaces (0.5 - 3.5 intercostal spaces) in comparison with the contralateral sides with significant differences between the group of 0 - 12 months and the group of 13 - 36 months and between the group of 0 - 12 months and the group of 37 - 60 months (both P < 0.05). The recurrent respiratory infection rate and of the groups of 0 - 12 months and 13 - 36 months were 47.1% and 27.3% respectively, both significantly higher than that of the group of 37 - 60 months (0%). The thorax deformity rate of the groups of 0 - 12 months and 13 - 36 months were 41.2% and 9.1% respectively, both significantly higher than that of the group of 37 - 60 months (0%). Three of the children in the group of 0 - 12 months (17.6%) had digestive system symptoms. CONCLUSION: Transfer of phrenic nerve operated on children younger than 3 years may cause abnormalities of respiratory system, thorax, and digestive system. The younger the patients the more severe the consequences of the operation. The children older than 3 years tolerate the operation better.

Age Factors↗
PubMed1987

[Effect of cholinesterase (ChE) reactivators on hemodynamics in animals. II. Reactions of the circulatory and respiratory systems of dogs after administration of ChE reactivators].

Different actions of pralidoxim and obidoxim were shown in studies on the influence of ChE reactivators (administered in doses of 10, 20, 40 mg/kg) on the circulatory and respiratory system. Blood flow velocity, arterial blood pressure in the carotid artery, the frequency and amplitude of breathing were recorded continuosly 60 min before and after intravenous injection of the reactivator. From these data the pulse rate, blood flow rate and the coefficient of the peripheral vascular resistance were calculated. At the same time pulse pressure was determined. Pralidoxim (PAM) acts parasympathicolitically on the heart-vascular system. It causes blood vessel shrinkage and decreases blood flow which is accounted for by increased vascular resistance by 20-40%. Such reactions cause, particularly after lower doses, increased arterial pressure and pulse rate by 15%. A 10 mg/kg dose of obidoxim increased pulse rate and blood flow for 15 min after the injection after 15 min the blood flow gradually decreased with simultaneous increase of the vascular resistance by 30%, as compared with the initial values. At larger doses it evoked mainly vascular reactions characterized by a constant increase of blood flow with simultaneous decrease of the vascular area. The ChE reactivators used stimulated the function of the respiratory system, which becomes apparent by increasing frequency of breathing with simultaneous increase of its amplitude. In these studies no differences were found in the action of obidoxim: Toxogonin (E. Merck) and Toxobidin (Polfa).

Animals↗
PubMed1990

Respiratory system compliance assessed by the multiple occlusion and weighted spirometer method in non-intubated healthy newborns.

In 28 healthy newborn infants (median age 3.5 days), we compared the weighted spirometer (WS) with the multiple occlusion (MO) method for measuring respiratory system compliance (Crs). The MO method was unsuccessful in 8 infants. On average the two methods gave comparable results for compliance (Crs,ws = 40.4 +/- 13.8 and Crs,MO = 45.2 +/- 10.4 mL.kPa-1) in the remaining 20 infants; however, within-individual differences were often considerable, so that the methods did not give interchangeable results. Individual pressure-volume curves almost always intercepted the volume axis below the functional residual capacity with the MO technique, compatible with dynamic elevation of end-expiratory lung volume (EEL) due to inspiratory muscle activity during expiration. A (small) negative volume intercept occurred in less than 50% of curves with the WS method; in these cases it probably reflects alinearity of the compliance curve, an alteration in laryngeal braking or in respiratory muscle control of EEL, or all of these. Both methods provide valuable means for the non-invasive determination of respiratory system compliance in newborn infants, the differences in Crs being small and of minimal physiological significance; however, for individual follow-up they should not be used interchangeably.

Female↗
PubMed1975

The composition of connective tissue macromolecules from bovine respiratory system.

Connective tissue macromolecules, glycosaminoglycans, glycoproteins, collagen, and elastin were isolated from different parts of the respiratory system and characterized. The materials included bronchiolar tissue, gas-exchange tissue, lung pleura, and tracheal mucosa. The similarity of the macromolecular composition of lung pleura and tracheal mucosa suggests a common cellular component in these structures. The high concentration of GAG and collagen in bronchiolar tissue is consistent with the cartilagenous nature of this tissue. Particularly interesting is the high content of heparin in all pulmonary structures, a relatively greater content of hyaluronic acid in gas-exchange tissue, and a high content of heparan sulfate and dermatan sulfate in vascular tissues. Elastin also occurs as a major fibrous structure. Although the biologic role of these connective tissue macromolecules has not been established, certain functional relationships are inferred.

Animals↗
PubMed1986

Respiratory systems of the Bacillus cereus mother cell and forespore.

The respiratory systems of the mother cells and forespores of Bacillus cereus were compared throughout the maturation stages (III to VI) of sporulation. The results indicated that both cell compartments contain the same assortment of oxidoreductases and cytochromes. However membrane fractions from young forespores were clearly distinct from those of the mother cell, i.e., lower content of cytochrome aa3, lower cytochrome c oxidase activity, higher concentration of cytochrome o, and a lower sensitivity of the respiration to the inhibiting effect of cyanide. This suggests that the cyanide-resistant pathway contributes more importantly to forespore respiratory activity than to activity in the mother cell compartment. During the maturation stages, the forespore NADH oxidase activity declined faster than in the mother cells. Other activities studied decreased steadily in both cell compartments. These findings together with the analysis of the kinetics of NADH-dependent reduction of cytochromes in the mature spore membranes indicated an impairment of electron flow between NADH dehydrogenase and cytochrome b. This impairment could be overcome by the addition of menadione.

Bacillus cereus↗
PubMed1990

Lecithin/sphingomyelin ratio from tracheal aspirates and compliance of the respiratory system in infants with bronchopulmonary dysplasia.

In 55 infants with respiratory distress syndrome the dynamic compliance of the respiratory system (CRS) was measured by pneumotachography during the course of the disease. Lecithin/sphingomyelin ratio (L/S) was evaluated at birth and every 10th day. Thirteen infants who developed bronchopulmonary dysplasia (BPD) had lower L/S ratios at birth than those infants without BPD (mean = 1.0 versus 3.5, p less than 0.01). During the course of disease, L/S ratios were variable and increased in all infants independently of outcome. In the first days of life CRS was low (0.30 ml/cm H2O/kg) in all infants independently of outcome. In infants with BPD who survived, CRS was significantly higher from the 30th day on than in infants who died from the disease (0.35 versus 0.23 ml/cm H2O/kg). Together with an decrease in oxygen supply at this time (less than 70%) the CRS is a reliable predictor of survival in cases of BPD.

Bronchopulmonary Dysplasia↗
PubMed1998

Effect of atmospheric pollution on the respiratory system.

Santiago de Chile has a high level of air pollution with ozone (O3), carbon monoxide (CO) and particles equal or smaller than 10 microns (PM10) usually exceeding the accepted standards. This situation should be noxious for the exposed population and particularly--in the case of O3 and PM10--for the respiratory system. However, such an effect is rather difficult to demonstrate and it depends on the type of population under study.

Air Pollution↗
PubMed1989

Density dependence of respiratory system impedances between 5 and 320 Hz in humans.

For respiratory system impedance (Zrs), the six-element model of DuBois et al. (J. Appl. Physiol. 8: 587-594, 1956) suggests three resonant frequencies (f1,f2,f3), where f1 is the result of the sum of tissue and airway inertances and tissue compliance and f2 is the result of alveolar gas compression compliance (Cg) and tissue inertance (Iti). Three such resonant frequencies have been reported in humans. However, the parameter estimates resulting from fitting this model to the data suggested that f2 and f3 were not associated with Cg and Iti but with airway acoustic properties. In the present study, we measured Zrs between 5 and 320 Hz in 10 healthy adult humans breathing room air or 80% He-20% O2 (HeO2) to gain insight as to whether airway or tissue properties are responsible for the f2 and f3. When the subjects breathed room air, f2 occurred at 170 +/- 16 (SD) Hz, and when they breathed HeO2 it occurred at 240 +/- 24 Hz. If this resonance were due to Cg and Iti it should not have been affected to this extent by the breathing of HeO2. We thus conclude that f2 is not due to tissue elements but that it is an airway acoustic resonance. Furthermore, application of the six-element model to analyze Zrs data at these frequencies is inappropriate, and models incorporating the airway acoustic properties should be used. One such model is based on the concept of equivalent length, which is defined as the length of an open-ended, cylindrical tube that has the same fundamental acoustic resonant frequency.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2004

[Clinical and physiological methods of examination for cardiac and respiratory systems in aluminium production workers of Kolsky North].

The authors presented clinical and physiologic studies of cardiac and respiratory systems and peripheral circulation among workers having various professions at aluminium production in Kolsky North. Multiple functional study methods were used including tachooscillography, electrocardiography, rheovasography, rheoencephalography, thermovision. The results enabled to specify duration and character of health disorders caused by occupational environment.

Adult↗