| 1. |
- Gabriel, B. L., et al.
(författare)
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Site-specific adhesion of Staphylococcus epidermidis (RP12) in Ti-Al-V metal systems
- 1994
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Ingår i: Biomaterials. - : Elsevier BV. - 0142-9612 .- 1878-5905. ; 15:8, s. 628-634
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Tidskriftsartikel (refereegranskat)abstract
- Staphylococcus epidermidis (RP12) adhesion patterns were studied on the following titanium (Ti)-aluminium (Al)-vanadium (V) metal systems: (i) microfabricated samples consisting of Ti, Al and V islands deposited onto Ti or V substrata, (ii) pure Ti, Al and V metals, and (iii) medical grade Ti6Al4-V alloy. All of these surfaces were covered with their respective oxides formed upon exposure of the metals to air. Quantitative analysis of the number of cells bound per unit area indicates that S. epidermidis (RP12) exhibits greatest adhesion to pure V surfaces. When exposed to surfaces having controlled spatial variations in chemical composition on the 10 mu m scale (microfabricated samples), the bacteria preferentially populate V islands versus Ti or Al substrata. In the case of the biphasic Ti6Al4V alloy, the bacteria tend to adhere to V-rich, mixed phase regions and phase boundaries. These findings demonstrate that enhanced and preferential adhesion of S. epidermidis (RP12) occurs on V surfaces in TI-Al-V metal systems and suggest that bacterial interactions are influenced by surface oxide composition.
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| 2. |
- Sennerby, Lars, 1960, et al.
(författare)
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A morphometric and biomechanic comparison of titanium implants inserted in rabbit cortical and cancellous bone.
- 1992
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Ingår i: The International journal of oral & maxillofacial implants. - 0882-2786. ; 7:1, s. 62-71
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Tidskriftsartikel (refereegranskat)abstract
- The removal torques for screw-shaped pure titanium implants inserted in rabbit tibia and the femoral part of the knee joint and the tissue response to these implants, as quantitated with light microscopic morphometry on ground sections, were compared after 6 weeks, 3 months, and 6 months. The bone surrounding the femoral intra-articular implants was mostly cancellous, while cortical bone was formed around the tibial implants. The torque needed to remove the intra-articular implants increased with time, but there was no such increase for the tibial implants. At 6 weeks, significantly less torque was needed to remove the intra-articular implants in spite of the fact that significantly more bone was found in the threads of these implants as compared with the tibial implants. When calculating the amount of bone in threads situated in the cortical and subchondral passage, more was found in the threads of the tibial implants, which corresponded to the higher removal torque. Additional light microscopic observations on implants unscrewed after 12 months in rabbit tibia indicated that rupture occurred between the implant surface and calcified bone. Findings indicate that the resistance to unscrewing is dependent on the amount of compact bone surrounding a titanium implant.
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| 3. |
- Sennerby, Lars, 1960, et al.
(författare)
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Tissue response to titanium implants in experimental antigen-induced arthritis.
- 1993
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Ingår i: Biomaterials. - : Elsevier BV. - 0142-9612. ; 14:6, s. 413-22
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Tidskriftsartikel (refereegranskat)abstract
- The healing of threaded, non-alloyed titanium implants in bone was studied in an experimental model of monoarticular arthritis in New Zealand white rabbits. Immunization with bovine serum albumin (BSA) and repeated intra-articular injections with BSA elicited an immune response and clinical signs of inflammation. Implants were inserted and 6 wk after surgery, with full weight-bearing, the rabbits were killed by perfusion fixation. Light microscopic morphometry showed that the cartilage was thinner and the subchondral bone had a lower density in the arthritic joints compared to the control side. The titanium implants in the arthritic joints had a lesser degree of mineralized bone-implant contact and surrounding bone than the implants inserted in control joints. The present study shows that the healing of titanium implants in the rabbit knee joint is impaired in experimental immunologic arthritis. This model may be useful for the study of biomaterial-tissue interactions under pathological conditions.
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| 4. |
- Platz-Christensen, Jens Jörgen, et al.
(författare)
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Endotoxin and interleukin-1 alpha in the cervical mucus and vaginal fluid of pregnant women with bacterial vaginosis.
- 1993
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Ingår i: American journal of obstetrics and gynecology. - : Elsevier BV. - 0002-9378. ; 169:5, s. 1161-6
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of our study was to determine the concentrations of endotoxin and interleukin-1 alpha in the cervical mucus and vaginal fluid of pregnant women who either did or did not have bacterial vaginosis.Samples of cervical mucus and vaginal fluid were collected from women in early pregnancy who had signs of bacterial vaginosis and from healthy control subjects. The samples were analyzed for the concentrations of endotoxin and interleukin-1 alpha. In addition, wet mounts were examined for signs of inflammation indicated by increased numbers of leukocytes.Both endotoxin and interleukin-1 alpha occurred in much higher concentrations (p < 0.0001, p < 0.0002) in both the cervical mucus and the vaginal fluid of women with signs of bacterial vaginosis than they did in healthy control subjects. A correlation was found between the interleukin-1 alpha concentrations in the vaginal fluid and the number of leukocytes as judged by a semi-quantitative evaluation of wet mounts (p = 0.0365). The concentrations of endotoxin correlated with those of interleukin-1 alpha in both fluids (vaginal fluid, p < 0.01; cervical mucus, p < 0.01).Our study shows that concentrations of endotoxin and interleukin-1 alpha in cervical mucus and vaginal fluid of women in early pregnancy who have bacterial vaginosis are significantly higher than the corresponding levels in control subjects.
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| 5. |
- Sennerby, Lars, 1960, et al.
(författare)
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Structure of the bone-titanium interface in retrieved clinical oral implants.
- 1991
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Ingår i: Clinical oral implants research. - : Wiley. - 0905-7161. ; 2:3, s. 103-11
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Tidskriftsartikel (refereegranskat)abstract
- 7 clinically stable, "osseointegrated", titanium implants, inserted in human jaws for 1-16 years, were retrieved for morphological analysis of the bone-titanium interface, using 3 different preparation techniques. The bone-titanium interface varied as judged from light microscopy of ground sections. The threads of the implants were well filled (79-95%) with dense lamellar bone as quantified with morphometry. A large fraction of the implant surface (56-85%) appeared to be in direct contact with the mineralized bone. In general, the non-bone areas consisted of pockets with osteocytes, bone marrow tissue and/or vessels. Sections were prepared for light microscopy and transmission electron microscopy using a fracture technique, where the implant was separated from the embedded tissue before sectioning, and an electropolishing technique, where the bulk part of the implant was electrochemically removed. In areas judged as direct mineralized bone-titanium contact in the light microscope, the interfacial structure varied at the ultrastructural level. In areas along the interface, unmineralized tissue was present either as a narrow 0.5-1 micron wide zone containing collagen fibril or as deeper pockets containing osteocytes or vessels. In areas with mineralized bone contact, an amorphous granular layer (100-400 nm wide) with no mineral was observed in the innermost interface bordering the mineralized bone, with an electron-dense lamina limitans-like line (approximately 50 nm thick). It is concluded that the bone-titanium interface of the 7 clinically retrieved titanium oral implants examined in the present study bone was heterogenous. In areas of a direct mineralized bone-titanium contact at the ultrastructural level, mineralized bone reached close to the implant surface, but was separated by an amorphous layer, being 100-400 nm thick.
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