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A new retrievable percutaneous vena cava filter was tested in vitro and in vivo in 15 foxhounds. In vitro, the new vena cava filter was compared with the standard Kimray-Greenfield filter and the Günther basket filter. The new filter is a stainless steel half-basket filter and is suitable for percutaneous antegrade or retrograde insertion through a 8.5 Fr introducer sheath. In vitro testing showed the filter causing no significant flow alterations and being highly effective in capturing medium- and large-sized thrombi; furthermore, fatigue testing revealed no breakage of the new filter, whereas the Günther basket filter showed breakage of the struts. In vivo studies showed no occlusion, major perforation, or filter migration during follow-up of 2 weeks to 6 months. Tilting of the filter postimplantation occurred in two out of 28 filters. Ten of 11 filters were successfully retrieved by the transjugular approach 2 weeks after implantation. The device seems to be suitable for temporary or permanent protection against pulmonary embolism.

In an experimental study, employing anaesthetized dogs, it was investigated whether cellular enzymes from peripheral skeletal muscle get into the circulating blood by diffusion across capillary membranes or by lymphatic transport. In the experimental group 1, the animals were anaesthetized only. The plasma activities of the four enzymes measured — lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, creatine kinase did not show any mentionable change during a time period of 6 h. In group 2 one hind limb of each animal was moved passively for 1 h. Alanine aminotransferase remained unchanged in plasma, the activities of the three other enzymes increased significantly. In group 3 one hind limb was made hypoxic by clamping the femoral blood vessels for 1 h. No activity changes were observed. When the period of hypoxia was followed by a 1-hour period of passive movement in group 4, the alterations in plasma activities were almost identical to those observed in group 2. In group 5 the experimental procedure was as in group 4, in addition the lymph from the thoracic duct was quantitatively withdrawn. The enzyme activities in plasma revealed a tendency to decrease rather than increase. Lymph flow increased significantly as well as the lymphatic activities of those enzymes which have high intracellular activities in muscle. The results prove, that enzymes from muscle are transported from the interstitial into the intravascular compartment mainly by lymphatic transport. Indications were found that the interruption of blood flow in one hind limb did not result in an enzyme release from muscle cells. It is discussed how changes in lymph flow, occurring during physical exercise for example, affect enzyme activities in plasma.

Summary:In the mixed body lymph of the thoracic duct and in the defined organ lymph of the liver and the intestine, the catalytic activity concentrations of up to sixteen enzymes arid the concentrations of albumin and protein were determiiied, äs well äs the transport rate of these substances and their lymph/plasma ratio. Thoracic duct lymph specimens were obtained from an extracorporeal lymph shunt in anaesthetized and conscious dogs and from short-term fistulas in anaesthetized rabbits, rats and mice. Additionally, rabbits and rats underwent passive motion of the bind limbs in another experimental trial. Thoracic duct flow in anaesthetized dogs is only half that seen in conscious dogs, due to bypassed muscular lymph. A similar flow change is seen during passive motion of bind limbs in anaesthetized rabbits and rats. From a literature review of flow in the four main lymphatics of the body, it is concluded that the thoracic duct flow should account for 50-70% of total body lymph flow. In the anaesthetized stäte, flow is mainly of visceral origin. In the conscious state and during passive motion the ihäteased flow is of miisfcular origin. In the latter case, the catalytic activities of enzymes like lactate dehydrogefiase, maläte döhydfogenase, creatine kinase, aldolase and phosphohexose isomerase, increase in lymph äs doels their lympH/plasma ratio. These enzymes have high catalytic activities in muscle* Their transport into the blöod increases 2-3-fold, due tö a doubling of l^mph flow. Reported data for anaesthetized and immobile animals theffcfore far tinderestimate the significahce of thoracic duct enzyme transport. Liver lymph was obtaihed frdftl anaesthetized dogs and rabbits. Our Unding that lymph catalytic activity for several enzymes is higher than in plasma iS not compatible with the proposed delivery of plasma proteins directly into the sinusöidäl space without priör ffl&ing with the Space of Disse. Enzymes in liver lymph should derive from parenchymal afld endothelial liiiiflg Sfells. Their site of delivery from the hepatocyte seems different from that of proteins. Liver lymph is an important transport route of enzymes into the blood. Intestinal lyiflßh was sampled from anaesthetized dogs, rabbits and rats. It was shown that most enzymes from the intestine are primarily released into the interstitial space and from there aie transported via the lymph into the blood. Thoracicus-, Leber-und Katalytische Enzymaktivitätskonzentration in Ductus