In vitro evaluation of the biofunctionality of osteoblasts cultured on DegraPol-foam.

The biofunctionality of osteoblasts cultured on DegraPol-foam, a biodegradable, elastic, and highly porous polyesterurethane-foam, was determined here to examine the possible use of this structure as bone repair material. Osteoblasts from rat tibia and from the cell line (MC3T3-E1) exhibited relatively high attachment and low doubling time that result in a confluent cell multilayer on the surface of the foam. They produced high concentrations of collagen type I and osteocalcin, and expressed increasing alkaline phosphatase activity.

DegraPol-foam: a degradable and highly porous polyesterurethane foam as a new substrate for bone formation.

Bone morphogenetic protein (BMP) is known to require a suitable carrier to induce ectopic bone formation in vivo. To evaluate the suitability of DegraPol-foam, a degradable, elastic, and highly porous polyesterurethane foam as carrier for BMP-induced bone formation, a fraction containing all the active BMPs (BMP cocktail) was combined with DegraPol-foam and implanted subcutaneously into rats. DegraPol-BMP scaffolds were found to induce osteogenesis 2 weeks after implantation as evidenced by morphological and biochemical observations.

Hepatic artery embolisation with a novel radiopaque polymer causes extended liver necrosis in pigs due to occlusion of the concomitant portal vein.

Background/aim: In an attempt to overcome some of the problems encountered with the materials available for liver embolisation, we investigated a novel radiopaque polymer of the polyurethane family (Degra-Bloc).

Methods: Hepatic artery embolisation of one liver lobe using polyurethane was performed in 19 healthy pigs. Microcirculatory changes were assessed by laser Doppler flowmetry.

Chondrocyte-biocompatibility of DegraPol-foam: in vitro evaluations.

Histological and biochemical investigations were carried out in order to evaluate the chondrocyte compatibility of a recently developed biodegradable polyesterurethane-foam (DegraPol-foam). Therefore, cell adhesion, cell growth, and the preservation of chondrocyte phenotype was measured in rat xyphoid chondrocytes seeded on DegraPol-foam. Chondrocytes, isolated from xyphoids of adult male rats, exhibited relatively high cell adhesion on DegraPol-foam (about 60% of that found on TCPS).

New versatile, elastomeric, degradable polymeric materials for medicine.

The present investigation was focused on the cell compatibility of recently developed biodegradable polyesterurethane-foam (DegraPol-foam) to chondrocytes and osteoblasts. Both chondrocytes and osteoblasts, isolated from adult male rats, exhibited relatively high cell adhesion on DegraPol-foam. Scanning electron microscopy (SEM) showed that cells grew on the surface and into the open cell pores of the foam.

Tissue engineering: a new approach in cardiovascular surgery--seeding of human fibroblasts on resorbable mesh.

Introduction: In tissue engineering the material properties of synthetic compounds are manipulated to enable delivery of dissociated cells onto a scaffold in a manner that will result in in vitro formation of new functional tissue. The seeding of human fibroblasts on resorbable mesh is a precondition of a successful creation of human tissue such as autologous cardiac valves.

Material And Methods: Polymeric scaffolds (n = 12) composed of polyglycolic acid (PGA) with a fiber diameter of 12-15 mm and a polymer density of 70 mg/ml were used as square sheets of 0.

Tissue engineering: a new approach in cardiovascular surgery: Seeding of human fibroblasts followed by human endothelial cells on resorbable mesh.

Objective: In tissue engineering the material properties of synthetic compounds are chosen to enable delivery of dissociated cells onto a scaffold in a manner that will result in in vitro formation of a new functional tissue. The seeding of human fibroblasts followed by human endothelial cells on resorbable mesh is a precondition of a successful creation of human tissues such as vessels or cardiac valves.

Methods: Polymeric scaffolds (n = 18) composed of polyglycolic acid (PGA) with a fiber diameter of 12-15 microm and a polymer density of 70 mg/ml were used as square sheets of 1 x 1 x 0.

Degradable and highly porous polyesterurethane foam as biomaterial: effects and phagocytosis of degradation products in osteoblasts.

Recently, a new class of biodegradable PHB-based polyesterurethane (DegraPol/btc) has been prepared and found to exhibit favorable cell and tissue compatibility. The present study has been designed to evaluate the response of primary isolated rat tibia osteoblasts to small crystalline particles of short-chain poly[(R)-3-hydroxybutyric acid] (PHB-P diameter: 2-20 microm), of fluorescent-labeled analogs (DPHP-P), and of lysine methyl ester as possible degradation products of DegraPol/btc. Observations made using confocal microscopy clearly indicate that osteoblasts have the capability of taking up PHB-P particles.

Magnetic resonance-guided laparoscopic interstitial laser therapy of the liver.

Background: There is a necessity for an imaging method during laparoscopy to get a three-dimensional access to the target. In this study we evaluated laparoscopic interstitial laser therapy of the liver under magnetic resonance imaging guidance.

Methods: Five domestic pigs underwent laparoscopy in an open-configuration magnetic resonance system.

Multiblock copolyesters as biomaterials: in vitro biocompatibility testing.

Cell adhesion, cell growth and cell activities of macrophages and fibroblasts, cultured on newly developed degradable multiblock-copolyesters were studied to examine the biocompatibility and the possible use of these polymers for medical applications. The biocompatibility and the biodegradability of the polymers were confirmed by subcutaneous implantation of polymer foils in rats. The newly developed polymers, two polyesters (DegraPol/bsc43 and DegraPol/bsd43) and a polyesterether (DegraPol/bst41), were found to exhibit good cell compatibility; the cell-to-substrate interactions induced neither cytotoxic effects nor activation of macrophages.

Development of degradable polyesterurethanes for medical applications: in vitro and in vivo evaluations.

To evaluate the biocompatibility of a newly developed degradable class of polyesterurethanes and their possible use as biomaterials, we investigated the cell and tissue interactions with these polymers using a small number of chemical base entities. The polymers were prepared by chain extension with diisocyanates of PHB/HV-diol and either PCL-diol or Diorez, another aliphatic polyester-diol. Regardless of the chemical composition of the four tested polyesterurethanes used as substrates, no morphological difference was observed either in the macrophages (macrophage cell line J774) or in the fibroblasts (fibroblast cell line 3T3) cultured on the polymers.

MR imaging-guided intravascular procedures: initial demonstration in a pig model.

With use of an open 1.5-T magnetic resonance (MR) imager and a tracking catheter, the authors successfully placed the catheter into the left or right sacral artery in pigs. The tracking catheter comprised a 5.

Experimental cryosurgery of the liver under magnetic resonance guidance.

The feasibility and the advantages of magnetic resonance (MR)-guided interstitial cryosurgery of the liver in an 0.5 Tesla open MR system have been evaluated. Cryosurgery was performed using an Erbocryo PS system with a nonmagnetic cryoprobe of 6 mm diameter.

[Testing bone implants in cell lines and human osteoblasts].

Two different types of cell-line and fresh human osteoblasts, cultured from cancellous bone grafts from the iliac crest, were used for the study. Three different biomaterials were compared regarding biocompatibility: titanium, steel and hydroxyapatite. The cells were fibroblast cell line (3T3), "osteoblast-like" cell line (MC3T3-E1), and fresh human osteoblasts (HOB) which we cultured in our laboratory.

Interactions of osteoblasts and macrophages with biodegradable and highly porous polyesterurethane foam and its degradation products.

The macrophage cell line J774, primary rat osteoblasts, and the osteoblast cell line MC3T3-E1 were used to examine the biocompatibility of a newly developed polyesterurethane foam and the possible use of this structure as bone-repair materials. The newly developed, biodegradable, and highly porous (pore size 100-150 microns) DegraPol/btc polyesterurethane foam was found to exhibit good cell compatibility; the cell-to-substrate interactions induced neither cytotoxic effects nor activation of macrophages. Osteoblasts and macrophages exhibited normal cell morphology.

Characterization of the cell response of cultured macrophages and fibroblasts to particles of short-chain poly[(R)-3-hydroxybutyric acid].

The known biodegradability of poly[(R)-3-hydroxybutyric acid] (PHB) in certain biological environments had led to its proposed use as a biodegradable, biocompatible polymer. Recently, a new, rapidly biodegradable block copolymer that contains crystalline domains of PHB blocks has been synthesized. During degradation of these polymers, the PHB domains are transformed in a first step into small crystalline particles of short-chain PHB.

[Initial clinical results in the treatment of peripheral arterial occlusive diseases using new percutaneous atherectomy equipment (REDHA-CUT)].

In 11 female and 13 male patients 29 symptomatic femoropopliteal occlusions were treated with a novel intraluminal endarterectomy device (REDHA-CUT). The pre-existing stenoses (71 +/- 9%) could be reduced to 29 +/- 18% (means +/- s.d.

Laparoscopic treatment of biliary and gastric outlet obstruction.

To avoid laparotomy in patients with biliary or gastric outlet obstruction in inoperable carcinoma of the pancreas, we evaluated the feasibility of double-bypass operation in 20 pigs. In model A (n = 10), biliary bypass was a Roux-en-Y loop for cholecystojejunostomy after choledochal clip occlusion. In model B (n = 10) an additional Roux-en-Y loop was attached to the stomach after transection of the duodenum.

[Experimental aortic aneurysm with endovascular technique].

We created a simple experimental aneurysm by a minimal operative trauma performing the balloon-dilatation and the rupture of the abdominal aorta of animals. The aorta of minipigs was dilated under angiographic control until the rupture became visible. The abdominal aorta and its branches were mapped out and measured.

Morphological and functional changes in canine kidneys following extracorporeal shock-wave treatment.

Extracorporeal shock-wave lithotripsy (ESWL) has rapidly become established worldwide as a routine method for treatment of nephro- and ureterolithiasis. Although initial studies showed no tissue-damaging effect by the shock waves, we found, in an animal experiment using canine kidneys, that the ESWL-induced damage to the renal parenchyma is more marked than originally assumed. The damage is limited to the area that was focused on, and heals relatively rapidly by connective tissue encapsulation with final cicatrisation without any further residual effects being observed up to the present.

The multimodal water jet dissector--a technology for laparoscopic liver surgery.

Unlabelled: In order to avoid laparotomy in patients with superficially and/or anatomically favourably located liver lesions, the feasibility of laparoscopic liver resection using an aqua jet was evaluated in 6 pigs. For this purpose a commercially available water jet dissector was adapted for laparoscopic use and modified to a multifunctional device providing aqua jet, suction and cautery. To improve laparoscopic vision during jet activity a hydrolaparoscope was used.

Technique of laparoscopic cholecystojejunostomy with a Roux-en-Y loop.

In order to avoid laparotomy in patients with biliary obstruction due to inoperable carcinoma of the pancreatic head, we evaluated the feasibility of a bypass operation using minimal invasive measures. A technique of laparoscopic cholecystojejunostomy was tested in adult pigs who had undergone clip occlusion of the distal common bile duct to imitate choledochal obstruction. Complete biliary bypass was restored with a cholecystojejunostomy via a Roux-en-Y loop using two circular staplers (21, 25, or 29 mm diameter), introduced through a prototype 33-mm-diameter trocar, used to effect the proximal and distal anastomoses.

[A new intraluminal endarterectomy instrument].

In 40 human cadaver arteries endarterectomy was performed using a new intravascular device. The system and technique are described. According to our preliminary laboratory experiences the new device proofed to be save and effective.