| 1. |
- Thomsen, Peter, et al.
(författare)
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Implants in the abdominal wall of the rat
- 1986
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Ingår i: Scandinavian Journal of Plastic and Reconstructive Surgery. - : Informa UK Limited. - 0036-5556. ; 20:2, s. 173-182
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Tidskriftsartikel (refereegranskat)abstract
- An experimental model is presented that allows qualitative as well as quantitative studies of the soft tissue response to implant materials used in reconstructive surgery. Plugs of non-alloyed titanium and polymers (Teflon, Delrin) were inserted into the abdominal wall of rats, with a portion of the plug penetrating through the peritoneum into the abdominal cavity. The tissue reaction was evaluated by means of light and electron microscopy for up to 9 weeks after insertion. Titanium implants were in direct contact with the connective tissue without intervening inflammatory cells. The defect in the peritoneum was sealed by a close apposition of the mesothelial membrane to the titanium surface and no connective tissue surrounded the intra-peritoneal portion of the plug. In contrast, a fibrous capsule surrounded the intra-peritoneal portion of Teflon and Delrin implants. A reactive zone consisting of active macrophages and giant cells was present at the surface of these implants separating the implant from the surrounding fibrous capsule. This study shows that the tissue response at the interface to foreign materials can be studied using light and electron microscopic techniques and that profound differences in tissue response exist between different materials.
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| 2. |
- Blomqvist, G, et al.
(författare)
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Differences in lodgement of tumour cells in muscle and liver
- 1988
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Ingår i: Clinical and Experimental Metastasis. - 1573-7276. ; 6:4, s. 285-289
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Tidskriftsartikel (refereegranskat)abstract
- Differences in the lodgement of circulating tumour cells in various organs are considered an important factor in metastatic organ selection. The present vital microscopic studies show that the pattern of intravascular arrest of tumour cells in muscle after intra-arterial injection is similar to that observed earlier, in the liver, after intraportal injection. However, parallel isotope studies on the lodgement process (at 5 min and 3 h after injection) showed that the tumour cells trapped in the muscle microvasculature were destroyed at a higher rate than in the liver. Tumour cells kept in test tubes, and thus not being subjected to the shearing forces of the circulation, had a higher survival rate than cells trapped in the muscle. The results indicate that stronger retardation forces acting on the tumour cells in muscle (arterial dissemination) than in the liver (venous dissemination) may be one mechanism behind the increased tumour cell destruction in muscle.
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| 3. |
- Braide, M, et al.
(författare)
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Optimized density gradient separation of leukocyte fractions from whole blood by adjustment of osmolarity
- 1986
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Ingår i: Journal of Immunological Methods. - : Elsevier BV. - 1872-7905 .- 0022-1759. ; 93:2, s. 183-191
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Tidskriftsartikel (refereegranskat)abstract
- Some of the compounds used for density gradient separation of blood cells have high osmolarities at the concentrations needed to create the required specific densities. Several mixed media use a combination of hyperosmolar shrinkage and red cell aggregation to improve cell separation. Due to the characteristics of Percoll density gradient medium the density and osmolarity of the gradient can be controlled separately. In the present study, Percoll gradients were used to determine the buoyant densities of different human blood cells at the osmolarities 300 mosM, 350 mosM and 400 mosM. Cell volumes were measured at the same osmolarities using a Coulter counter with channelyzer. As expected, the cell buoyant densities increased and the cell volumes decreased at the higher osmolarities used. There were, however, quantitative differences between the cells with respect to the effects of an increased osmolarity, making a 350 mosM density gradient the most effective in separating mononuclear leukocytes from polymorphonuclear leukocytes. A 400 mosM gradient offered the best possibilities to separate red blood cells from polymorphonuclear leukocytes. A one-step centrifugation procedure, based on these principles, is presented. This procedure makes possible the simultaneous purification of mononuclear leukocytes and polymorphonuclear leukocytes, suitable for functional assays.
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| 4. |
- Holgers, K M, et al.
(författare)
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Soft tissue reactions around percutaneous implants: a clinical study of soft tissue conditions around skin-penetrating titanium implants for bone-anchored hearing aids
- 1988
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Ingår i: American Journal of Otology. - 0192-9763. ; 9:1, s. 56-59
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Tidskriftsartikel (refereegranskat)abstract
- Some patients with hearing impairment cannot use conventional hearing aids. One solution for these patients is the use of bone conduction hearing aids; however, this kind of equipment is associated with several problems related to the necessity for a good contact between the transducer and the temporal bone. Direct bone contact would be an ideal solution provided that safe and reaction-free skin penetration and a safe and permanent bone anchorage could be achieved. Branemark et al have developed a procedure to furnish edentulous patients with fixed bridges using titanium implants. This report is focused on the clinical status of the soft tissue adjacent to the 67 skin-penetrating devices in 60 patients. The patients have been followed between 3 and 96 months on 313 occasions, which represents a total observation time of 1515 months of clinical performance. Only one implant was extracted due to adverse skin reaction, giving a failure rate of 0.07% per month. This is comparable with the failure rate of cardiac pacemakers 0.02-0.04% per month).
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| 5. |
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| 6. |
- Linder, L, et al.
(författare)
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Clinical aspects of osseointegration in joint replacement. A histological study of titanium implants
- 1988
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Ingår i: Journal of Bone and Joint Surgery: British Volume. - 2044-5377. ; 70-B:4, s. 550-555
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Tidskriftsartikel (refereegranskat)abstract
- In an experimental clinical study, 25 implants of pure titanium were inserted into the proximal tibia of 11 volunteer patients, four with rheumatoid arthritis and seven with osteoarthritis. The implants were removed from five weeks to 24 months later and detailed histological analysis was performed. The implants generally healed with direct bone-metal contact, showing so-called osseointegration. Only one of the 21 implants which had been in place for over five months did not show osseointegration, probably because of inadequate primary contact with bone. The presence of rheumatoid disease did not prevent osseointegration, but accompanying osteoporosis seemed to be a risk factor.
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| 7. |
- Thomsen, P, et al.
(författare)
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Acute synovitis induced by preformed immune complexes
- 1986
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Ingår i: Scandinavian Journal of Rheumatology. - : Informa UK Limited. - 1502-7732 .- 0300-9742. ; 15:2, s. 134-142
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Tidskriftsartikel (refereegranskat)abstract
- The morphology of acute immune complex (IC) elicited synovitis in rabbit knee joints was studied, as well as IC-induced leukocyte activation in vivo and in vitro. Acute synovitis was induced by intra-articular injection of in vitro preformed, complement activating bovine serum albumin (BSA)-anti-BSA IC. Within 30 min, migration of polymorphonuclear granulocytes (PMNGs) was observed. Scanning electron microscopy showed that adhering, apparently activated leukocytes were attached to the synovial lining, often forming clusters. Phagocytosis of IC was evident, as immunoglobulins were detected within the leukocyte cytoplasm by the direct immunofluorescence technique. At the peak accumulation of PMNGs, focal erosions of the synovial lining were observed. Later, monocytes and macrophages appeared and degenerated PMNGs were found, sometimes within the cytoplasm of large macrophages. Chemiluminescence experiments showed a maximum in vitro activation of leukocytes by complement activating IC formed near optimal precipitation proportions and in slight antigen excess, whereas IC in large antigen excess gave a smaller and later response.
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| 8. |
- Thomsen, P, et al.
(författare)
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Joint fluid leukocyte activation by preformed immune complexes
- 1986
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Ingår i: Inflammation. - 0360-3997. ; 10:3, s. 243-256
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Tidskriftsartikel (refereegranskat)abstract
- Acute synovitis was induced in rabbit knee joints by intraarticular injection of preformed bovine serum albumin (BSA) -anti BSA immune complexes (ICs). Polymorphonuclear granulocytes (PMNGs) which had migrated into joints injected with ICs were degranulated and contained ICs as revealed by electron microscopy and were activated as revealed by the measurement of chemiluminescence (CL). In contrast, leukocytes from control joints injected with BSA and normal rabbit serum as well as glycogen-elicited peritoneal leukocytes did not display any morphological changes and did not show CL. Compared to cells from other sources, leukocytes from IC joints showed a decreased CL response when stimulated in vitro with ICs but not with opsonized zymosan, suggesting a stimulus-specific modification of the PMNG responsiveness. Inhibition experiments showed that oxygen radicals and formation of arachidonate metabolites, mainly of the lipoxygenase pathway, were involved in the CL response of the IC-stimulated joint fluid PMNGs. Our observations on morphology, activity, and responsiveness of emigrated cells from the various sources suggest, together with previous observations, that the reaction of leukocytes in IC-induced synovitis consists of an initial migration phase not related to an increased CL and a subsequent activation phase characterized by degranulation, phagocytosis of ICs and increased CL.
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