| 1. |
- Strömbeck, Louise, 1958, et al.
(författare)
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Prevotella bivia can invade human cervix epithelial (HeLa) cells.
- 2007
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Ingår i: APMIS : acta pathologica, microbiologica, et immunologica Scandinavica. - : Wiley. - 0903-4641 .- 1600-0463. ; 115:3, s. 241-51
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Tidskriftsartikel (refereegranskat)abstract
- Prevotella bivia has been associated with female upper genital tract infections and an increased risk of preterm delivery. In this study, the adherence and invasion capacity of P. bivia was investigated using a cervix epithelial cell line. P. bivia was furthermore analysed for its ability to evoke a proinflammatory cytokine response in epithelial cells. The invasion capacity, defined as the number of bacteria recovered from lysed HeLa cells infected with P. bivia, varied considerably among five strains, all of which were isolates from women with bacterial vaginosis. One P. bivia strain (P47) gave rise to an approximately 120-fold higher number of intracellular bacteria (7 x 10(3) bacteria per 1 x 10(5) cells) compared with the least invasive strain. Three strains expressed an intermediate or low invasiveness, showing an approximately 3- to 40-fold higher number of intracellular bacteria per 1 x 10(5) cells compared with the least invasive strain. The intracellular localization of P47 in phagosome-like vesicles was confirmed by transmission electron microscopy. All P. bivia strains adhered to HeLa cells to the same extent (range 14-22 bacteria per cell) as analysed by interference microscopy. No correlation was found between adhesion and invasion capacity of the strains. Furthermore, no fimbriae-like structures were observed on P47 detected by scanning electron microscopy or negative staining. Analysis of TNF-alpha, IL-1alpha, IL-6, IL-8, and IL-18 in P. bivia-stimulated HeLa cells showed low levels of only IL-6 and IL-8 for the most invasive P. bivia strain P47. Thus, the induction of IL-6 or IL-8 secretion appeared to be associated with invasion capacity. This work provides evidence that some P. bivia isolates can invade human cervix epithelial. Thus, a strong capacity for invasion and a weak proinflammatory cytokine-inducing capacity in P. bivia are suggested to be virulence factors in establishing a low-grade upper genital tract infection.
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| 2. |
- Mark, Hans, 1961, et al.
(författare)
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Effects of fracture fixation stability on ossification in healing fractures
- 2004
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Ingår i: Clinical orthopaedics and related research. - 0009-921X. ; :419, s. 245-50
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Tidskriftsartikel (refereegranskat)abstract
- Temporal distribution of intramembranous and endochondral bone formation was studied in experimental fracture defects in rats under different stability of fracture fixation and fracture environments. Animals were surgically treated with a specially developed external fixation construct: Group 1 had 42 rats with a 0-mm fracture gap with bone ends touching corresponding to an axial stiffness of 265.00 +/- 34.00 N/mm and Group 2 had 42 rats with a 2-mm fracture gap corresponding to an axial stiffness of 30.38+/- 2.07 N/mm. From each group, six animals were sacrificed at 4 days and 1, 2, 3, 4, 6, and 12 weeks. Qualitative histologic and morphometric analyses revealed that less fixation rigidity and increased fracture gap induces a later response of bone formation and greater endochondral bone formation leading to prolonged time for full ossification. Furthermore, in the early phase of fracture healing temporal distribution and histologic characteristics of periosteal and intramedullary bone formation are similar and not influenced by rigidity and fracture environment. Results also showed that if tissues associated with the intramedullary region are preserved, intramedullary bone formation is substantial. Finally, histologic data indicate that woven bone might be a prerequisite for the differentiation process of endochondral bone formation.
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| 3. |
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| 4. |
- Murata, Y., et al.
(författare)
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Nucleus pulposus-induced apoptosis in dorsal root ganglion following experimental disc herniation in rats
- 2006
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Ingår i: Spine. - 1528-1159. ; 31:4, s. 382-90
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Tidskriftsartikel (refereegranskat)abstract
- STUDY DESIGN: The mechanisms behind the formation of a characteristic tissue reaction at the surface of the dorsal root ganglion (DRG) exposed to nucleus pulposus was studied with special reference to apoptosis using electron microscopy and immunohistochemistry in rats. OBJECTIVES: To study the mechanism of the characteristic tissue reaction at the surface of the DRG exposed to nucleus pulposus. SUMMARY OF BACKGROUND DATA: Recently, it was observed that local application of nucleus pulposus may induce a characteristic tissue reaction at the surface of the DRG. This change occurred as early as 1 day after the application of nucleus pulposus. METHODS.: Herniation of nucleus pulposus was created in the L4-L5 disc in rats. The L4 DRG were resected 3 and 24 hours after surgery. The sections of the specimens were observed using light and electron microscopy. The sections were processed for immunohistochemistry using antibodies to single-stranded DNA (ssDNA), caspase 3, and tumor necrosis factor alpha (TNF). RESULTS: There were typical changes of the cell nuclei observed by light and electron microscopy, especially those of the small-sized cells, in the DRG 24 hours after application of nucleus pulposus, indicating the presence of apoptosis. The presence of ssDNA, caspase 3, and TNF further enhanced the impression that there was apoptosis in the DRG. Nucleus pulposus induced apoptosis in the DRG at the site of application within as little as 24 hours. CONCLUSIONS: Nucleus pulposus herniated from the disc induced apoptosis in at the surface of the DRG exposed to nucleus pulpous as early as 24 hours after exposure.
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| 5. |
- Murata, Yasuaki, et al.
(författare)
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The role of tumor necrosis factor-alpha in apoptosis of dorsal root ganglion cells induced by herniated nucleus pulposus in rats.
- 2008
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Ingår i: Spine. - 1528-1159. ; 33:2, s. 155-62
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Tidskriftsartikel (refereegranskat)abstract
- STUDY DESIGN: The mechanisms of apoptosis underlying a characteristic tissue reaction at the surface of the dorsal root ganglion (DRG) exposed to nucleus pulposus were studied in rats with special reference to the role of tumor necrosis factor-alpha (TNF). OBJECTIVE: To study the characteristic tissue reaction at the surface of the DRG exposed to nucleus pulposus with special reference to the role of TNF. SUMMARY OF BACKGROUND DATA: Nucleus pulposus cells are capable of producing TNF. Recently, local application of nucleus pulposus was shown to induce a characteristic tissue reaction at the DRG surface due to apoptosis. METHODS: Recombinant TNF was applied to the DRG to mimic L4-L5 disc herniation in rats. The DRGs were resected 24 hours after surgery. Sections of the specimens were processed for immunohistochemistry using antisera to single-stranded DNA, Caspase 3, and TNF, and observed by light and electron microscopy. RESULTS: Typical apoptotic changes of the cell nuclei were observed in the DRG after application of TNF. The presence of single-stranded DNA, Caspase 3, and TNF further confirmed the occurrence of DRG cell apoptosis. CONCLUSION: TNF seemed to play a key role in induction of apoptosis of DRG cells, which resembled that induced by application of nucleus pulposus.
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| 6. |
- Nannmark, Ulf, 1958, et al.
(författare)
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Inhibition of leukocyte phagocytosis by serotonin and its possible role in tumor cell destruction.
- 1992
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Ingår i: Cancer letters. - : Elsevier BV. - 0304-3835. ; 62:1, s. 83-6
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Tidskriftsartikel (refereegranskat)abstract
- Intraportal tumour cell (TC) injection activates platelets which release serotonin (5-HT). Thrombocytopenia or 5-HT blockade decrease the hepatic lodgement of the injected TCs. A hypothetical explanation of this is 5-HT inhibition of TC killing by phagocytes (e.g. leukocytes and Kupffer cells). In this study, leukocyte phagocytosis was analysed by a chemiluminescence technique at different 5-HT concentrations. Significant inhibition of phagocytosis occurred at 5-HT concentrations of 10(-4) M to 10(-8) M, with maximum inhibition at 10(-4) M. Comparable concentrations of 5-HT may be found locally in the liver during TC infusion, supporting the hypothesis that 5-HT has an inhibitory effect on phagocyte-mediated TC killing.
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| 7. |
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| 8. |
- Olmarker, Kjell, 1958, et al.
(författare)
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Microvascular effects of chondroitinase ABC and chymopapain. An in vivo experimental study on hamsters and rabbits.
- 1990
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Ingår i: Clinical orthopaedics and related research. - 0009-921X. ; :257, s. 274-9
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Tidskriftsartikel (refereegranskat)abstract
- Immediate and long-term microvascular effects of chondroitinase ABC, 200 unit/ml, were analyzed in ten hamsters. The immediate effects on the microcirculation were studied by vital microscopy following local injection in the cheek pouch. There were no detectable effects on the microvascular blood flow during the 60 minutes of observation for chondroitinase ABC or the control. A therapeutic concentration (2000 pKat/ml) of chymopapain stopped the microcirculation in the injected area immediately, with numerous microbleedings at the border zone. Long-term effects were studied after subcutaneous injections in the ears of six rabbits. Chondroitinase ABC and the control did not cause any macroscopic or microangiographic effects. However, light microscopy showed a moderate inflammatory reaction in the subcutaneous layer for both chondroitinase ABC and the control. Chymopapain induced severe effects on the cartilage and surrounding tissues. Microangiography revealed a vessel-free zone at the injection site. Since 200 units/ml of chondroitinase ABC is four to eight times higher than the concentration that might be used for chemonucleolysis, i.e., dissolution of intervertebral discs by local enzyme injection, the present investigation suggests a wide margin of safety regarding the potential effects on blood vessels in tissues surrounding the disc.
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| 9. |
- Albertsson, Per, 1964, et al.
(författare)
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Differential locomotion of long- and short-term IL-2-activated murine natural killer cells in a model matrix environment.
- 2007
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Ingår i: Scandinavian journal of immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 66:4, s. 402-9
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Tidskriftsartikel (refereegranskat)abstract
- Tumour infiltration by activated natural killer (A-NK) cells is a pre-requisite for tumour eradication by adoptive NK cell transfer. Extravasated A-NK cells do not always succeed in reaching the crucial target cell conjugation. Therefore, we wished to study A-NK cell locomotion and interactions with melanoma cells in a matrix environment (Matrigel) by electron, confocal and fluorescence microscopy. Two distinct patterns of A-NK cell-mediated matrix disintegration were revealed during incubation of tumour cells and A-NK cells in Matrigel: (1) A-NK cells pre-cultured for 5 days altered the homogeneous texture of the Matrigel, an initial microporous appearance became a loose filamentous meshwork by 24 h. Matrix degrading protease inhibitors could not fully prevent this, but could delay the process; and (2) A-NK cells pre-cultured for 6 days or more, instead formed large excavations in the Matrigel leaving the remaining matrix less affected compared to the effects by the younger A-NK cells. By histochemical staining with Cupromeronic Blue, the excavations were shown to contain proteoglycan material. Protease inhibitors had no discernable effect on the development of the excavations. The conspicuous capacity of A-NK cells to disintegrate extracellular matrix and the formation of large excavations seems only partially to depend on matrix-degrading proteases. Formation of extracellular proteoglycan material is suggested to facilitate A-NK cell locomotion within a matrix environment.
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| 10. |
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