PubMed Health⌕ Search

Biomedical subjects

S Valind

Publications and source records attributed to S Valind.

42 records · Page 3Linked to original sources
PubMed1993

Mechanics of respiratory system in healthy anesthetized humans with emphasis on viscoelastic properties.

The classic model of the respiratory system (RS) is comprised of a Newtonian resistor in series with a capacitor and a viscoelastic unit including a resistor and a capacitor. The flow interruption technique has often been used to study the viscoelastic behavior under constant inspiratory flow rate. To study the viscoelastic behavior of the RS during complete respiratory cycles and to quantify viscoelastic resistance (Rve) and compliance (Cve) under unrestrained conditions, we developed an iterative technique based on a differential equation. We, as others, assumed Rve and Cve to be constant, which concords with volume and flow dependency of model behavior. During inspiration Newtonian resistance (R) was independent of flow and volume. During expiration R increased. Static elastic recoil showed no significant hysteresis. The viscoelastic behavior of the RS was in accordance with the model. The magnitude of Rve was 3.7 +/- 0.7 cmH2O.l-1 x s, i.e., two times R. Cve was 0.23 +/- 0.051 l/cmH2O, i.e., four times static compliance. The viscoelastic time constant, i.e., Cve.Rve, was 0.82 +/- 0.11s. The work dissipated against the viscoelastic system was 0.62 +/- 0.13 cmH2O x 1 for a breath of 0.56 liter, corresponding to 32% of the total energy loss within the RS. Viscoelastic recoil contributed as a driving force during the initial part of expiration.

Adult↗
PubMed1992

Cardiovascular disease in systemic lupus erythematosus. A study of 75 patients form a defined population.

All patients with systemic lupus erythematosus in a prospective, epidemiologically based study within a defined area in southern Sweden were invited to participate in an investigation of cardiac function. From 1981 to 1988, 101 patients were included in the study, and 75 of them were investigated according to a fixed protocol by echocardiography, Doppler cardiography, electrocardiography (ECG) at rest and at exercise, and myocardial scintigraphy (in patients whose ECG became abnormal during exercise). IgG anticardiolipin antibodies (IgG aCL) were determined by ELISA. Twenty of the 75 patients (27%) had valvular disease and 12 of these (60%) had increased concentrations of IgG aCL, compared with 12 of 55 (22%) without valvular disease (p less than 0.01). Pericardial effusion was detected in 14 patients (19%) during the study period. Mild pulmonary hypertension was found in 11 patients (16%), who also had increased frequency of IgG aCL. Myocardial infarction had occurred in 7 patients, 3 of whom were women less than 40 years of age. Echocardiography revealed regional hypokinesis or akinesis in 5 of the patients with myocardial infarction. Exercise testing revealed low work capacity in 13 of 54 patients (24%), the limiting symptoms being mainly exhaustion or musculoskeletal pain. An abnormal resting ECG was found in 9 of the patients participating in the exercise test. During exercise, abnormal ST-depression was observed in 8 patients, 2 of whom developed angina. Myocardial scintigraphy was performed in 6 of these patients, revealing reversible uptake defects in all. Prolonged glucocorticoid treatment was associated with valvular abnormalities as well as myocardial infarction. Valvular abnormalities and IgG aCL appeared to be risk factors for cerebral infarction.

Adult↗
PubMed1992

Long-term evaluation of penicillamine or cyclofenil in systemic sclerosis. Results from a two-year randomized study.

In a two-year prospective therapeutic trial 13 patients with systemic sclerosis (SSc) were treated with penicillamine, 9 with cyclofenil, and 7 with neither. At entry skin involvement and esophageal, lung, heart, and kidney function did not differ significantly between the groups. Reevaluation after one and two years did not show any significant changes in skin, esophageal, heart, and kidney manifestations, while lung function had slightly improved in both drug-treatment groups. This study thus shows little overall effect of penicillamine and cyclofenil, although both drugs may arrest worsening of pulmonary dysfunction.

Adult↗
PubMed1989

Lung function in patients with systemic lupus erythematosus and persistent chest symptoms.

Twelve consecutive patients with systemic lupus erythematosus (SLE) and chest symptoms of at least 3 months' duration were investigated with spirometry, lung mechanics at rest and exercise, diffusion capacity and right heart catheterization. Vital capacity (88% of predicted, p less than 0.05), and FEV1 (84%, p less than 0.01) were decreased in the study group, but spirometric and diffusion capacity abnormalities were moderate compared with previous studies. The single breath CO2 test showed, in six patients, ventilation-perfusion mismatch with patterns typical for either bronchial obstruction or vascular disease. Non-respiratory factors were responsible for reduction of working capacity (on average 68% of predicted normal values (p less than 0.001]. Two patients with pulmonary hypertension were identified by right heart catheterization. One of them had overlap features with the CREST syndrome. Both these patients had abnormal SBT-CO2 test and diffusion capacity, along with diffuse perfusion defects on perfusion scintigraphy. The low frequency of pulmonary function abnormalities in this study suggests that irreversible pulmonary damage is uncommon in SLE.

Adult↗