A reproducible tourniquet-shock has been produced in hind limbs of dogs by unilateral and bilateral extremity ischemia. The following parameters have been measured for analysing the function of the cardiovascular system: mean aortic pressure, heart rate, cardiac output, intraventricular pressure and left ventricular pressure. From these data the stroke volume, stroke work, total peripheral resistance and the parameters of heart contractility dp/dtmax, dp/dtmax:IP and t-dp/dtmax were derived. During the ischemic period all circulatory parameters did not change in comparison to the controls. A tourniquet-shock developed upon recirculation of the ischemically stressed extremity which was more pronounced after bilateral than after unilateral hind leg ischemia. After release of the tourniquet all animals with unilateral tourniquet survived an observation period of 5 hours duration, whereas 6 out of 8 dogs with bilateral tourniquet died of heart failure. Upon release of the tourniquet, the cardiac output raised up to 140% of the normal value: the abruptly decreasing aortic pressure was fully compensated by a tachycardia from 100 to 190 (beats/minute). The parameters dp/dtmax:IP and t-dp/dtmax indicated a distinct increase of the left ventricular contractility in the early tourniquet-syndrom. Already after 30 minutes an increasing circulatory depression developed indicative of the decrease in aortic pressure, and enddiastolic pressure. At the same time an increase of heart rate and total peripheral resistance occurred. The parameters of left ventricular contractility did not change markedly during the course of shock except for the final stage.

Animals↗

PubMedDate not supplied

Popliteal artery stenting using flexible tantalum stents.

PURPOSE: To evaluate the safety and efficacy of stent therapy for the treatment of residual stenoses after percutaneous transluminal angioplasty (PTA) of popliteal stenoses and occlusions. METHODS: In a prospective single-center study, flexible tantalum stents were implanted in 32 popliteal arteries for the treatment of residual stenosis greater than 50% after PTA of stenoses (n = 17) or occlusions (n = 15) in the P1 (n = 16), the P2 (n = 13), or both P1 and P2 segment (n = 3). Follow-up patency was assessed by clinical examination, ankle-brachial index, and color Doppler sonography or angiography. RESULTS: Early stent thrombosis (10 days): 1 of 32 arteries (3%). 1-year and 2-year primary patency rate (PPR): 81% +/- 7.1% and 74% +/- 9.1%, respectively. 1-year PPRs for subgroups: stented stenoses versus stented occlusions: 88% +/- 7.8% vs 73% +/- 12.0%, p = 0.12; good lower limb runoff versus poor: 84.0% +/- 8.7% vs 76.0% +/- 12.4; p = 0.09; P1 versus P2: 77.3% +/- 9.8% vs 85.7% +/- 9.4%, p = 0.38. Recurrent PTA lesions treated with stents showed higher restenosis rate than de novo lesions. CONCLUSION: The results of stent therapy of residual popliteal stenosis after PTA are encouraging and warrant further investigation.

Aged↗

PubMedDate not supplied

Asymmetric reconstitution of the erythrocyte anion transport system in vesicles of different curvature: implications for the shape of the band 3 protein.

The anion transport protein of the human erythrocyte membrane, band 3, was solubilized and purified in solutions of the non-ionic detergent nonaethylene glycol lauryl ether and then reconstituted in spherical egg phosphatidylcholine bilayers as described earlier (U. Scheuring, K. Kollewe, W. Haase, and D. Schubert, J. Membrane Biol. 90, 123-135 (1986)). The resulting paucilamellar proteoliposomes of average diameter 70 nm were transformed into smaller vesicles by French press treatment and fractionated according to size by gel filtration. The smallest protein-containing liposomes obtained had diameters around 32 nm; still smaller vesicles were free of protein. All proteoliposome samples studied showed a rapid sulfate efflux which was sensitive to specific inhibitors of band 3-mediated anion exchange. In addition, the orientation of the transport protein in the vesicle membranes was found to be "right-side-out" in all samples. This suggests that the orientation of the protein in the vesicle membranes is dictated by the shape of the protein's intramembrane domain and that this domain has the form of a truncated cone or pyramid.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗

PubMedDate not supplied

ATP-hydrolysis as driving force for transport processes in isolated renal plasma membrane vesicles.

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Adenosine Triphosphate↗