Biomedical subjects

R Rüfer

Publications and source records attributed to R Rüfer.

At least 37 records · Page 2Linked to original sources

PubMed1990

Positive influence of nifedipine on early-stage minipig shock lung.

Mechanical and biochemical lesions can be observed in shock lung. To investigate the influence of the calcium antagonist nifedipine on these lesions, we produced shock lung in male minipigs. Three groups (control, thrombin, and thrombin + nifedipine; n = 5) were formed. In the second and third group thrombin was administered intravenously (400 IU/kg body weight) over a period of 2 h. After that the animals received aminocaproic acid (100 mg/kg body weight/h) throughout the rest of the study. Nifedipine was administered in the third group at a dosage of 46 micrograms/kg body weight/h. During the investigation period coagulation and hemodynamic status were examined as well as blood gas levels. Then the isolated lungs were examined. Without nifedipine there was a significant decrease in arterial PO2, an increase in airway opening pressure (Pi), and a decrease in weight-specific end-inspiratory lung compliance (Ci). These changes were not observed under the influence of nifedipine, after which the results were similar to the control group. This demonstrates a positive influence of nifedipine on the acid-base status and the investigated lung mechanical parameters.

Animals↗

PubMed1988

Mechanical properties of isolated fetal miniature pig lungs after substitution with fluorocarbons.

In our present study we tried to inflate and stabilize isolated immature lungs of fetal minipigs in gestation age of 95 days (= 85% of total normal gestation period) with different fluorocarbons. Based on our previous experiences, the immature lungs at day 95 are almost non inflatable with air. For our experiments we used fluorocarbon 43 (FC-43) with a surface tension of 16 mN/m and fluorocarbon 72 (FC-72) with a surface tension of 12 mN/m. Eighteen fetal immature lungs were used. In group 1 the lungs were rinsed with FC-43; in group 2 the rinse solution was FC-72, and in group 3 the lungs were untreated. After removing the fluorocarbon, in the case of groups 1 and 2, the lungs were artificially ventilated. Pressure-volume (p-v) curves were registered in the beginning (immediately after FC lavage), after 10 and 20 min of artificial ventilation. Airway opening pressure (pi) and weight-specific end-inspiratory lung compliance (ci) were investigated. Statistically significant differences in weight-specific end-inspiratory compliance were found between FC groups and untreated group 3, but no stabilization could be seen during the investigation period of 20 min. No statistically significant improvement in weight-specific end-inspiratory compliance was observed between group 1 and 2, although the compliances of group 2 with FC-72 were better than those of group 1 with FC-43 in three p-v diagrams registered in the beginning and after 10 and 20 min of artificial ventilation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1988

Mechanical properties of fetal minipig lungs after substitution of surfactant with fluorocarbon and dipalmitoylphosphatidylcholine.

Respiratory distress syndrome (RDS) is characterized by quantitative and qualitative disturbances of surface active substances (surfactant). Therefore, intratracheal surfactant substitution is a favored subject of clinical investigations. In our study we tried to inflate and stabilize lungs in two steps: first, lungs were rinsed with a fluorocarbon and, second, artificially ventilated with a dipalmitoylphosphatidylcholine (DPPC) aerosol, the mean component of surfactant. Sixteen isolated fetal minipig lungs of day 95 (85% of the total gestation period) were used. From one pair of lungs one lung served as control (group 1), whereas the other was treated with DPPC (group II). In both groups the lungs were rinsed first with a fluorocarbon (FC-72, surface tension 12 mN/m). This maneuver was followed by an artificial ventilation with an aerosol of either salt solution (group I) or DPPC (group II) for 40 min. To characterize lung mechanics, static pressure volume curves were registered at 0, 20, and 40 min after fluorocarbon lavage. Airway opening pressure (pi), end-inspiratory volume (vi), and weight-specific end-inspiratory lung compliance (ci) were investigated. As biochemical parameters of the lungs we determined phospholipidphosphate content and DPPC, sphingomyelin (SM), and lysophosphaditylcholine (LPC) of the lung tissue. Significant differences were found with regard to phospholipidphosphate and DPPC content. No difference was seen in static pressure volume diagrams at the end of the investigation period.

1,2-Dipalmitoylphosphatidylcholine↗

PubMed1987