Biomedical subjects

W V Cardoso

Publications and source records attributed to W V Cardoso.

24 records · Page 2Linked to original sources

PubMed1991

A comparison between the isovolume and the end-inflation occlusion methods for measurement of lung mechanics in rats.

The isovolume method is one of the most used techniques to assess the mechanical properties of the lungs in ordinary challenge tests and in toxicological studies. It has been considered that isovolume lung resistance (RL) could assess central airway calibre in such tests, whereas dynamic elastance (EL,dyn) would reflect the elastic properties of lung parenchyma. However, peripheral phenomena, such as Pendelluft and stress relaxation, can interfere with RL measurements, especially in disease. In order to investigate the contribution of such phenomena to isovolume RL and EL,dyn, we compared the results provided by isovolume technique with those given by the end-inflation occlusion method (EIOM) in 12 normal Wistar rats. We found similar values for total lung resistance (RL,max) and isovolume RL. Homogeneous resistance (RL,mm), which describes airway calibre, comprised about 30% of RL in the tidal volume range. Values of EL,dyn calculated by the EIOM were approximately 20% greater than the corresponding value measured during spontaneous breathing. Our data indicate that isovolume RL is significantly affected by tissue forces and cannot be interpreted as a pure index of airway size.

Airway Resistance↗

PubMed1989

Biological effects of air pollution in São Paulo and Cubatão.

Rats were used as biological indicators of air quality in two heavily polluted Brazilian towns: São Paulo and Cubatão. They were exposed for 6 months to ambient air in areas where the pollution was known to be severe. The following parameters were studied and compared to those of control animals: respiratory mechanics, mucociliary transport, morphometry of respiratory epithelium and distal air spaces, and general morphological alterations. The results showed lesions of the distal and upper airways in rats exposed in Cubatão, whereas the animals from São Paulo showed only alterations of the upper airways but of greater intensity than those observed in the Cubatão group. There are both qualitative and quantitative differences in the pollutants of these places: in São Paulo automobile exhaust gases dominate and in Cubatão the pollution is due mainly to particulates of industrial sources. The correlation of the pathological findings with the pollutants is discussed and it is concluded that biological indicators are useful to monitor air pollutions which reached dangerous levels in São Paulo and Cubatão.

Air Pollutants↗

PubMed1989

Expiratory mechanics before and after uncomplicated heart surgery.

In 12 mechanically ventilated anesthetized paralyzed patients undergoing cardiac surgery for either coronary bypass or for correcting valvular dysfunction volume, airflow, tracheal, esophageal, and transpulmonary pressures were measured. Respiratory system elastance and resistance were partitioned into their lung and chest wall components throughout tidal relaxed expiration. Measurements were performed prior to thoracotomy and just after rib cage closure. Before surgery, patients with valvular disease had significantly higher respiratory system and lung elastances and resistances than those with ischemic heart disease. After surgery, patients with valvular disease showed a decrease in respiratory system and lung resistances. Surgery strikingly modified chest wall resistive properties in both groups. Postoperatively, the mechanical properties of the respiratory system were very similar in valvular and ischemic patients.

Adult↗

PubMed1987

Mechanics in rats by end-inflation occlusion and single-breath methods.

In six mechanically ventilated anesthetized (pentobarbital sodium, 30 mg/kg) paralyzed rats (187-253 g body wt) volume, airflow, and tracheal, esophageal, and transpulmonary pressures were measured. Respiratory system elastic and resistive properties were partitioned into their lung and chest wall components after end-inflation occlusion of the airways subsequent to constant-flow inspirations and during relaxed expiration ensuing release of occlusion. The values provided by both methods were similar. Mean respiratory system, lung, and chest wall elastances amounted to, respectively, 5.536, 3.440, and 2.097 cmH2O.ml-1. Mean values of intrinsic respiratory system, pulmonary, and chest wall resistances (at flows of 3.5 ml.s-1) were 0.235, 0.144, and 0.091 cmH2O.ml-1.s, respectively. Resistive pressure-flow relationships for the respiratory system, lung, and chest wall were also determined during the entire tidal expiration. A linear relationship was found for the former, whereas power functions best described the others: the pulmonary pressure-flow relationship exhibited an upward concavity and that for the chest wall presented an upward convexity.

Airway Resistance↗

PubMed1987

Pre- and postoperative inspiratory mechanics in ischemic and valvular heart disease.

In 12 mechanically-ventilated, anesthetized, paralyzed patients undergoing cardiac surgery for either coronary bypass (six subjects) or to correct valvular disfunctions, volume, airflow, tracheal, esophageal, and transpulmonary pressures were measured. Respiratory system elastance and resistance were partitioned into lung and chest wall components. Resistances were further split into homogeneous and uneven elements. Measurements were performed prior to thoracotomy and just after rib cage closure. Before surgery, valvular patients had significantly higher elastances and uneven resistances of the respiratory system and lung than those with ischemic heart disease. Postoperatively, the patients presented with an increase in respiratory system and lung elastances, a decrease in pulmonary resistance, and a rise in chest wall resistance. Surgically induced mechanical changes were similar in ischemic and valvular patients.

Adult↗

PubMed1987

[Ulerythema ophryogenes and folliculitis ulerythematosa reticulata].

Three fundamental alterations characterize keratosis pilaris syndrome: follicular keratosis, vasodilatation and atrophy. Ulerythema ophryogenes and folliculitis ulerythematosa reticulata are types of the syndrome that localize on the eyebrows and cheeks and sometimes affect the ears and scalp. Punctuate atrophy and hair rarefaction may result. The patients frequently exhibit keratosis simplex as well. The clinical picture is considered to be an autosomal dominant genodermatosis and its treatment is ineffective.

Adolescent↗