The value of magnetic resonance (MR) imaging, with two-dimensional (2D) spin-echo and FISP (fast imaging with steady-state precession) and FLASH (fast low-angle shot) three-dimensional (3D) gradient-echo sequences, for the detection of hyaline cartilage defects of the femoral condyle and the tibial plateau, was investigated in an animal model. In eight dogs, the anterior cruciate ligament was transected in one knee joint, resulting in rapid development of osteoarthritis with degeneration of the hyaline cartilage. At autopsy, 24 cartilage lesions were found, which were classified into four grades. The overall detection of cartilage lesions with MR imaging was poor. Only five of the 24 lesions were visible on 2D spin-echo images, while 11 of 24 were visible on 3D FISP images and 15 of 24 were seen on 3D FLASH images. The best results were obtained in advanced stages of cartilage degeneration, involving ulceration and complete abrasion of the cartilage layer. Signal loss or signal intensity increase in the cartilage layer was seen inconsistently in grades 3 and 4 degeneration. In this animal model, 2D spin-echo imaging was inadequate for the diagnosis of hyaline cartilage lesions, while 3D gradient-echo imaging permitted satisfactory diagnosis in only grade 4 cartilage disease.

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PubMedDate not supplied

New retrievable percutaneous vena cava filter: experimental in vitro and in vivo evaluation.

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.

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PubMedDate not supplied

[Diffusion of various beta lactam antibiotics into infected tissues of the locomotor system in experimental osteomyelitis].

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Animals↗

PubMedDate not supplied

Application of surfaces with end point attached heparin to extracorporeal circulation with membrane lungs.

Application of heparin bonded surfaces (HBS) in the extracorporeal circuit (ECC) might avoid or at least reduce conventional heparin administration and would be of great benefit, especially in long-term perfusion. In this study, six sheep had a veno-venous bypass using membrane oxygenators with either total HBS or, in a control group, with untreated surfaces. Under strictly standardized conditions (body weight, drugs, geometry of tube, catheters, etc.), the animals in both groups received 300 IU/kg heparin before the catheterization as a bolus injection. In both groups, the measured heparin level decreased within 6 hours to zero, accompanied by a fall of other coagulation parameters (ACT, PTT etc.) to normal. In the control group, the ECC failed at this point because of clots in the oxygenators, whereas perfusions using HBS continued without further changes in clotting parameters until 12, 22, and 53 hours when the experiments were stopped intentionally. During the first 6 hours platelets showed a similar decrease in number in both groups and were comparable with conventional heparin treatment during further ECC periods. Other parameters, such as AT III, FXa, fibrinogen, and leukocytes were normal in both groups. The plasma hemoglobin increased markedly at the end of perfusion time in the control group but remained low even after 53 hours of ECC with HBS. The results indicate that the use of such completely heparin bonded systems can lead to a drastic reduction in systemic heparin administration.

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