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PubMed1978

[Diseases caused by diisocyanates. 1. Irritation of the respiratory system and skin].

Toluylene diisocyanate (TDI) has an uncommon importance in the production of irritation of respiratory system. In the last few years less volatile isocyanate compounds have been substituted for TDI. Commercial available diphenylmethane diisocyanate (MDI) and polymethylene polyphenyl isocyanate (PAPI) were analyzed in 1971. The analysis indicated the presence of 21% TDI in several samples. It is evident, with respect to the relatively high vapor pressure of TDI, that such impurities will be able to cause air concentrations in excess of the current threshold limit value (TLV) of 0.02 ppm. Liberation of TDI by heat from varnish insulinations is a difficult problem. This problem was described as "an old hazard in new guise". Especially, in a soldering process on polyurethane coated wire, excess of TLV is possible in unfavourable conditions. By the regulation that the concentration of TLV must not exceed 0.02 ppm and by the use of new non-volatile isocyanate the risk of acute and subacute intoxications has considerably subsided. Chronic irritations of respiratory system and asthma-like diseases, however represent still an unsolved problem.

Cyanates↗
PubMed1992

The respiratory system as an exercise limiting factor in normal trained subjects.

Recently, we have shown that an untrained respiratory system does limit the endurance of submaximal exercise (64% peak oxygen consumption) in normal sedentary subjects. These subjects were able to increase breathing endurance by almost 300% and cycle endurance by 50% after isolated respiratory training. The aim of the present study was to find out if normal, endurance trained subjects would also benefit from respiratory training. Breathing and cycle endurance as well as maximal oxygen consumption (VO2max) and anaerobic threshold were measured in eight subjects. Subsequently, the subjects trained their respiratory muscles for 4 weeks by breathing 85-160 l.min-1 for 30 min daily. Otherwise they continued their habitual endurance training. After respiratory training, the performance tests made at the beginning of the study were repeated. Respiratory training increased breathing endurance from 6.1 (SD 1.8) min to about 40 min. Cycle endurance at the anaerobic threshold [77 (SD 6) %VO2max] was improved from 22.8 (SD 8.3) min to 31.5 (SD 12.6) min while VO2max and the anaerobic threshold remained essentially the same. Therefore, the endurance of respiratory muscles can be improved remarkably even in trained subjects. Respiratory muscle fatigue induced hyperventilation which limited cycle performance at the anaerobic threshold. After respiratory training, minute ventilation for a given exercise intensity was reduced and cycle performance at the anaerobic threshold was prolonged. These results would indicate the respiratory system to be an exercise limiting factor in normal, endurance trained subjects.

Adolescent↗
PubMed1982

The basicranium of Plio-Pleistocene hominids as an indicator of their upper respiratory systems.

Our analyses of extant primates have shown that a relationship exists between the degree of flexion of the basicranium and the location of upper respiratory structures such as the larynx and pharynx (Laitman et al., 1978). Based upon these relationships, we have previously used the basicrania of late Pleistocene hominids as a guide to the reconstruction of their upper respiratory anatomy (Laitman et al., 1979). This study continues our approach by examining the basicrania of Plio-Pleistocene hominids and reconstructing their upper respiratory systems. Nine Plio-Pleistocene hominids had basicrania complete enough to be used in this study. These included the originals of Sts 5, MLD 37/38, SK 47, SK 48, SK 83, Taung, KNM-ER 406, OH 24, and a cast of OH 5. Craniometric analysis of the basicrania of these specimens showed that they had marked similarities to those of extant pongids. These basicranial similarities between Plio-Pleistocene hominids and extant apes suggest that the upper respiratory systems of these groups were also alike in appearance. As with living nonhuman primates, the early hominids probably exhibited a larynx and pharynx positioned high in the neck. This high position would have permitted an intranarial epiglottis to be present during both normal respiration and the ingestion of a liquid bolus of food. The high position of the larynx would have also greatly restricted the supralaryngeal portion of the pharynx available to modify laryngeal sounds. It is thus possible that the Plio-Pleistocene hominids exhibited modes of breathing, swallowing and vocalizing similar to those of living apes.

Animals↗
PubMed1981

Design of the mammalian respiratory system. I. Problem and strategy.

This paper introduces a series of reports on the structure and function of the respiratory system of mammals. We propose and justify the hypothesis that structural design is a limiting factor for O2 flow at each level of the respiratory system. The background, the reasons, and the plan for the studies are described. The main approach is to compare the size of respiratory structures with maximal O2 consumption in a series of mammals spanning several orders of magnitude in body size. The papers that follow present the methods and results for maximal O2 consumption, pulmonary diffusing capacity, mitochondrial volume, and capillary density in muscles.

Animals↗
PubMed1989

Human respiratory tract model for radiological protection: a revision of the ICRP Dosimetric Model for the Respiratory System.

In 1984, the International Commission on Radiological Protection (ICRP) appointed a task group of Committee 2 to review and revise, as necessary, the ICRP Dosimetric Model for the Respiratory System. The model was originally published in 1966, modified slightly in Publication No. 19, and again in Publication No. 30 (in 1979). The task group concluded that research during the past 20 y suggested certain deficiencies in the ICRP Dosimetric Model for the Respiratory System. Research has also provided sufficient information for a revision of the model. The task group's approach has been to review, in depth, morphology and physiology of the respiratory tract; deposition of inhaled particles in the respiratory tract; clearance of deposited materials; and the nature and specific sites of damage to the respiratory tract caused by inhaled radioactive substances. This review has led to a redefinition of the regions of the respiratory tract for dosimetric purposes. The redefinition has a morphologic and physiological basis and is consistent with observed deposition and clearance of particles and with resultant pathology. Regions, as revised, are the extrathoracic (E-T) region, comprising the nasal and oral regions, the pharynx, larynx, and upper part of the trachea; the fast-clearing thoracic region (T[f]), comprising the remainder of the trachea and bronchi; and the slow-clearing thoracic region (T[s]), comprising the bronchioles, alveoli, and thoracic lymph nodes. A task group report will include models for calculating radiation doses to these regions of the respiratory tract following inhalation of representative alpha-, beta-, and gamma-emitting particulate and gaseous radionuclides. The models may be implemented as a package of computer codes available to a wide range of users. This should facilitate application of the revised human respiratory tract model to worldwide radiation protection needs.

Aerosols↗
PubMed1982

Respiratory system compliance as seen from the cardiac fossa.

Changes in cardiac size and shape should impose stresses on the surrounding lung and chest wall. To examine pressure-volume relationships of the cardiac fossa we measured pressures required to increase the pericardial volume of freshly killed dogs at different levels of lung inflation, first by expanding the pericardium uniformly and then by expanding only the left ventricle. In both cases we obtained linear pressure-volume relationships, the slopes of which expressed an apparent compliance. Compliance decreased as lung volumes were increased by raising end-expiratory pressure, and compliance with symmetrical pericardial filling exceeded that with asymmetrical (left ventricular) distension. These compliances were compared with the total respiratory system compliance measured during tidal ventilation, and we found that the compliance of the cardiac fossa was significantly less than would be predicted from lung and chest wall compliances as classically measured. We concluded that the respiratory system imposes a finite compliance load on cardiac filling that raises local epicardial pressure above ambient pleural pressure. This respiratory system load depends upon lung volume and the cardiac shape change.

Animals↗
PubMed1983

Gross anatomy of the respiratory system of the bowhead whale, Balaena mysticetus.

Components of the respiratory system from seven bowhead whales have been examined. The paired and laterally curved external nares are passively closed by a valve-like mass located in the rostral, lateral, and ventral walls of the nasal vestibules. Nasal septal cartilages are paired smooth plates rostrally changing to accordion-like folds caudally. The epiglottic and arytenoidal protuberances of the larynx are typically cetacean, but blunt. The cricoid cartilage is not a complete ring, but an elongated, inverted, trough-shaped structure. The thyroid cartilage is trough-shaped with elongated cranial cornua curving dorsocaudally from each thyroid lamina. A conical mass of skeletal muscle serves as the floor of the short trachea and also surrounds the termination of the laryngeal sac. The trachea is dorsoventrally compressed, lacks a tracheal bronchus, and its width equals its length. The principal bronchi give rise to lobar bronchi at obtuse angles. Large segmental bronchi branch extensively from lobar bronchi near the mediastinal lung surface. The lungs are rectangular and of nearly uniform thickness throughout, without external or internal lobulation.

Animals↗
PubMed1999

[Influences of chest deformation by upper abdominal retractor on respiratory system impedance during abdominal surgery].

The present study was carried out to clarify the effects of chest deformation by upper abdominal retractor on respiratory system impedance during abdominal surgery. We measured the impedances of respiratory system (RS), lung, and chest wall (CW) in nine anesthetized paralyzed subjects employing a pseudorandom noise forced volume oscillation technique. These measurements were performed before and after the lifting chest wall by upper abdominal retractor. The effects of chest deformation was significant on the impedances of RS, lung, while no discernible effect was found in CW impedance. Lifting chest wall decreased RS resistance which was totally accounted for by the decrease in lung resistance, whereas the lifting did not affect reactance in either RS or lung. The mathematical modeling showed the significant lifting effect on the resistance of the parenchyma. In conclusion, change in RS mechanics produced by chest deformation by upper abdominal retractor is dominated in lung but not in CW. Among the lung mechanical components, parenchyma is the primary site of the lifting effect.

Adult↗
PubMed1992

Variations in function and design: testing symmorphosis in the respiratory system.

We explore the question of whether and to what extent the large variation in energy requirements observed among mammals is related to variations in the design of the respiratory system, from the lung to the mitochondria in muscle cells. Resting metabolic rate is determined by body size (allometric variation). Maximal rates of O2 consumption (VO2 max) also vary in a regular manner with body size, but adaptive variation allows some species to achieve much higher values than others of the same body size. We, therefore, consider adaptive variation as modulation of structures and functions above those determined by allometric variation. A model is presented that separates functional and design parameters at four steps of the respiratory cascade: the pulmonary gas exchanger, heart and blood, microvasculature, and mitochondria. The variations observed in these parameters are analyzed with respect to those in energy demand and are discussed in relation to the hypothesis of symmorphosis. We conclude that the design of the internal steps of the respiratory system (mitochondria, capillaries, blood, and heart) is matched to functional demand, whereas the lung maintains a variable excess of morphometric diffusing capacity which may be related to the facts that the lung has limited malleability and that it forms the interface with the environment.

Animals↗
PubMed1998

Studies on the respiratory system in alkaliphilic Bacillus; a proposed new respiratory mechanism.

Respiratory electron transfer systems in two alkaliphilic Bacillus species, YN-1 and YN-2000, were investigated In the cyanide-sensitive pathway of the obligate alkaliphilic Bacillus YN-1, the terminal enzyme was a caa3-type cytochrome c oxidase constituting up to just 10% of the total oxygen-reducing activity, while 90% of the respiratory activity was due to cyanide-insensitive, nonproteinaceous material with a molecular weight of 662. These results were consistent with the cyanide-tolerant growth of the bacterium. The molecular and catalytic properties of the nonproteinaceous material were not identical with those of menaquinones extracted from the bacterium. Furthermore, the nonproteinaceous material was also found in the facultative alkaliphilic Bacillus YN-2000, when that bacterium was cultivated in alkaline conditions. A new respiratory oxygen-reducing mechanism comprising a nonproteinaceous component and a catalase is proposed for these alkaliphilic Bacillus species.

Bacillus↗
PubMed2005

[Key words, essential tools for bibliographic research: analysis of usage in Archivos de Bronconeumología for respiratory system knowledge areas].

OBJECTIVE: To analyze key word usage in Archivos de Bronconeumología, by comparing words used in the journal to those used in the Index Medicus database within various respiratory system knowledge areas, and to determine whether usage has changed over time. MATERIAL AND METHODS: Original articles published in Archivos de Bronconeumología from 1994 through 2001 were reviewed manually to gather the key words used. The list was translated to English and then compared to the medical subject heading (MeSH) terms used in the PubMed Browser. RESULTS: Seven hundred six original articles published in the study period used a total of 1163 key words. Matches with MeSH terms were found for 62% (n=46) of the key words in smoking research, 48% (n=52) in asthma, 39% (n=82) in respiratory insufficiency and sleep disorders, 60% (n=49) in diagnostic and treatment techniques, 61% (n=35) in tuberculosis, 65% (n=87) in nontuberculous infections, 61% (n=121) in oncology, 60% (n=37) in circulation, 55% (n=47) in pleural diseases, 48% (n=21) in pathophysiology, and 64% (n=68) in interstitial diseases. We did not see a clear tendency in the evolution of the journal's key word usage for the knowledge areas analyzed during the study period. The percentage of matching key words held steady around 50% over the last 3 years. CONCLUSIONS: Respiratory system key words in the knowledge areas we investigated are used correctly in Archivos de Bronconeumología only about 50% of the time.

Information Storage and Retrieval↗
PubMedDate not supplied

Cellular defense of the avian respiratory system. Influx of phagocytes: elicitation versus activation.

We studied various means of inducing avian phagocytes to migrate to the respiratory tract. No significant and consistent increases in the number of avian respiratory phagocytes (ARP) were elicited by intravenous inoculation with Escherichia coli lipopolysaccharide (LPS), Saccharomyces cerevisiae glucan (G), and Freund's incomplete adjuvant (FIA) in a water-in-oil-in-water emulsion; subcutaneous inoculation with the LPS-G-FIA homogenate; or aerosolized exposure to LPS-G-FIA, thioglycolate, and proteose-peptone. Intravenous inoculation with heat-killed Corynebacterium parvum resulted in a significant increase in the number of ARP by day 6 after inoculation; intratracheal inoculation of C. parvum effected a more rapid and higher level of phagocyte migration to the respiratory tract. Intratracheally administered E. coli induced significant migration of phagocytes to the respiratory system so that by 24 hours postinoculation, the group average number of ARP was about 50-100 times as high as the number in unstimulated control birds. None of the birds yielding high numbers of phagocytes from their respiratory tract had signs of respiratory disease.

Animals↗
PubMed1999

Bronchodilator delivered by metered dose inhaler and spacer improves respiratory system compliance more than nebulizer-delivered bronchodilator in ventilated premature infants.

We compared the change in passive respiratory system compliance (Crs) and resistance (Rrs) after albuterol aerosol treatment administered by either low-flow nebulizer (NEB) or a metered dose inhaler (MDI) and spacer into a ventilator circuit. We hypothesized that albuterol delivered to ventilated infants older than 7 days of life by an MDI and a spacer would improve Crs more than albuterol delivered by a low-flow nebulizer. The treatments were administered 6 hr apart to premature infants with Crs < or = 0.8 mL/cm H2O per kg, requiring ventilation after 7 days of age. Patients served as their own controls and treatment order was randomized. Eighteen studies were performed in eight infants before and 1 and 3 hr after treatment. Differences between methods were compared by analyses of variance. Mean (range) birth weight and study age were 888 (619-1,283) g and 12 (7-29) days, respectively. Mean respiratory system compliance increased by 34% with MDI and by 11% with NEB at 1 hr after treatment (P < 0.02). By 3 hr after treatment, Crs returned to baseline with both methods of aerosol delivery. There was no significant difference in Rrs between the two methods at 1 and 3 hr after treatment. We conclude that albuterol delivered by MDI improves Crs more than low-flow NEB in ventilated premature infants.

Administration, Inhalation↗
PubMed1980

A pulse method of measuring respiratory system compliance.

We describe a new method of measuring respiratory system compliance (Crs) that appears to detect whether respiratory muscles are relaxed. A pulse airflow, 0.3/s, is blown into the mouth through a pneumotachograph. Mouth pressure is recorded on the abscissa of an oscilloscope. Inflated volume, integrated from the flow signal, is recorded on the ordinate. After an initial step shift of pressure related to the flow resistance of the subject, pressure increases linearly at a rate inversely proportional to Crs. Crs is calculated from the slope of the volume-pressure line. With relaxed subjects, repeated pulses yield straight lines with similar slopes (mean coef of variation = 4.8%). When subjects are not relaxed, the pulse produces irregular lines. In 15 normal subjects who could relax. Crs averaged 0.86 +/- 0.016 (SD) 1/cmH2O. When normalized for body size by dividing by the vital capacity, the mean value was 0.021 +/- 0.0024 cmH2O-1, which agrees with published values. We conclude that the pulse method accurately measures Crs and has the advantage of detecting respiratory muscle relaxation.

Atmospheric Pressure↗
PubMed2006

[Angiotensin converting enzyme inhibitors and respiratory system].

Angiotensin converting enzyme inhibitors (ACE-I) are generally-applied medicaments in treatment and prevention of many illnesses. Although they are generally well-tolerated by an organism, their application might cause side-effects in a respiratory system, such as: dry cough, angioedema. They can also cause or strengthen bronchospasm. In this paper we analyse mechanism responsible for ACE-I side-effects concerning the respiratory system. The paper also highlights a positive effects of lung fibrosis and reduction of pneumonia risk in elderly people.

Adult↗
PubMed1998

[Effects of low concentration ozone on the respiratory system of mice].

Effects of low concentration of O3 on the respiratory system in mice were studied in the present study. Mice were exposed to 0.1, 0.25 and 1.0 mg/m3 of O3, respectively for 8 h per day for 3 days. Cilia in brochia, Lipid peroxide (LPO) in lung tissue and phagocytic function of macrophage in mice were examined. The results showed that there were cilia damage in the 1.0 mg/m3 group and swelling of mitochondrias as well as endoplasmic reticulums in the 0.25 mg/m3 group. But no damage was found in the group of 0.1 mg/m3. Furthermore, phagocytic rates in the 0.25 and 1.0 mg/m3 groups were significantly lower than that of control group (P < 0.01). No differences in LPO leads were found.

Animals↗
PubMed1985

Structural evaluation of the respiratory system.

The theoretical and practical bases for morphological evaluation of the respiratory system useful for inhalation toxicology are reviewed. For most studies we recommend a comprehensive gross examination followed by in vitro tracheal infusion of a fixative containing both glutaraldehyde and formaldehyde in cacodylate buffer. Lungs fixed in this manner are suitable for LM, SEM, and TEM and lung volumes can be determined. The airway orientation of many lesions and the potential for gradients of damage are considered in the lung sampling plan. While LM of paraffin sections continues to be the basic method for evaluation, the SEM and TEM, especially when ancillary methods are used, provide valuable additional information. The use of backscattered electrons and energy-dispersive X-ray analysis in the SEM provides information concerning the localization and elemental analyses of particles. Cytochemical procedures characterize biological activities of specific cell types and are becoming more widely used. Morphometry permits correlation of quantified structure with physiological and biochemical data.

Animals↗