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Träfflista för sökning "WFRF:(Thorlacius Henrik) srt2:(2000-2004)"

Sökning: WFRF:(Thorlacius Henrik) > (2000-2004)

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  • Torkvist, L, et al. (författare)
  • Heparin protects against skin flap necrosis: relationship to neutrophil recruitment and anti-coagulant activity
  • 2004
  • Ingår i: Inflammation Research. - : Birkhäuser Verlag. - 1420-908X. ; 53:1, s. 1-3
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective and design: Heparin has been shown to improve survival of surgical skin flaps. However, it is not known whether the protective effect of heparin is related to it's anticoagulative or anti-inflammatory effects. Methods: Surgical flaps were raised in the dorsal skin of Sprague-Dawley rats. Neutrophil recruitment was determined by measuring the tissue content of myeloperoxidase (MPO) and clotting time was estimated by assessment of activated partial thromboplastin time (APTT) in plasma. Results: Administration of heparin (150 U/kg) significantly increased skin flap survival from 44 % in vehicle-treated controls to 91 %. This heparin treatment increased APTT by 4.5 fold. However, administration of 150 U/kg of heparin had no effect on skin flap neutrophil recruitment. In contrast, we found that the polysaccharide fucoidan reduced MPO and also improved skin flap survival. Conclusions: In conclusion, we demonstrate that protective effect of clinically relevant doses of heparin correlates with its' ability to prolong clotting time and not to inhibition of neutrophil accumulation in the healing of skin flaps.
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4.
  • Zhang, X W, et al. (författare)
  • Important role of CD18 in TNF-alpha-induced leukocyte adhesion in muscle and skin venules in vivo
  • 2000
  • Ingår i: Inflammation Research. - : Birkhäuser Verlag. - 1420-908X. ; 49:10, s. 529-534
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVE: To examine the role of CD 18 in tumor necrosis factor-alpha (TNF-alpha)-induced leukocyte adhesion and extravasation in vivo. MATERIAL: Male wild-type (WT) and mutated mice with hypomorphic expression of CD 18. METHODS: Intravital microscopy was used to quantitate leukocyte-endothelium interactions provoked by TNF-alpha (0.5 microg) in the cremaster muscle and dorsal skin microcirculation. Tissue recruitment of leukocytes was evaluated in wholemounts of the cremaster muscle and in air pouches in the dorsal skin after TNF-alpha stimulation. RESULTS: TNF-alpha markedly increased venular leukocyte adhesion and recruitment in the cremaster muscle and skin in WT. Notably, in CD 18-targeted animals, leukocyte adhesion triggered by TNF-alpha challenge was significantly reduced by 58% and 72% in venules of the cremaster muscle and skin, respectively. Moreover, in CD18-mutants, tissue accumulation of polymorphonuclear leukocytes (PMNLs) provoked by TNF-alpha in the muscle and skin was decreased by 84% and 70%, respectively. Interestingly, the observed level of reduction in TNF-alpha-induced neutrophil adhesion and recruitment in CD18 gene-targeted animals corresponded well with the decrease in CD 18 expression on neutrophils from these mice, i.e. the surface density of CD18 was reduced by 77% in mutants compared to WT. Differential analysis revealed that the extravascular leukocytes comprised more than 90% PMNLs, indicating that neutrophils were the main inflammatory cell responding to TNF-alpha activation. Notably, the expression of CD18 increased by more than two-fold on extravasated neutrophils compared to circulating neutrophils in the peripheral blood both in WT and mutant animals. CONCLUSIONS: These findings suggest that CD18 is a dominant mediator of firm neutrophil adhesion to venular endothelial cells in the muscle and skin stimulated by TNF-alpha in vivo. In addition, this decreased adhesion in CD18-mutants attenuates leukocyte extravasation in response to TNF-alpha activation. Thus, inhibition of CD 18-function may provide an important strategy to inhibit leukocyte recruitment in cytokine-dependent diseases.
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5.
  • Johnson, Louis Banka, et al. (författare)
  • Radiation enteropathy and leucocyte-endothelial cell reactions in a refined small bowel model
  • 2004
  • Ingår i: BMC Surgery. - : BioMed Central (BMC). - 1471-2482. ; 4
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Leucocyte recruitment and inflammation are key features of high dose radiation-induced tissue injury. The inflammatory response in the gut may be more pronounced following radiotherapy due to its high bacterial load in comparison to the response in other organs. We designed a model to enable us to study the effects of radiation on leucocyte-endothelium interactions and on intestinal microflora in the murine ileum. This model enables us to study specifically the local effects of radiation therapy. METHOD: A midline laparotomy was performed in male C57/Bl6 mice and a five-centimetre segment of ileum is irradiated using the chamber. Leucocyte responses (rolling and adhesion) were then analysed in ileal venules 2 - 48 hours after high dose irradiation, made possible by an inverted approach using intravital fluorescence microscopy. Furthermore, intestinal microflora, myeloperoxidase (MPO) and cell histology were analysed. RESULTS: The highest and most reproducible increase in leucocyte rolling was exhibited 2 hours after high dose irradiation whereas leucocyte adhesion was greatest after 16 hours. Radiation reduced the intestinal microflora count compared to sham animals with a significant decrease in the aerobic count after 2 hours of radiation. Further, the total aerobic counts, Enterobacteriaceae and Lactobacillus decreased significantly after 16 hours. In the radiation groups, the bacterial count showed a progressive increase from 2 to 24 hours after radiation. CONCLUSION: This study presents a refinement of a previous method of examining mechanisms of radiation enteropathy, and a new approach at investigating radiation induced leucocyte responses in the ileal microcirculation. Radiation induced maximum leucocyte rolling at 2 hours and adhesion peaked at 16 hours. It also reduces the microflora count, which then starts to increase steadily afterwards. This model may be instrumental in developing strategies against pathological recruitment of leucocytes and changes in intestinal microflora in the small bowel after radiotherapy.
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6.
  • Klintman, Daniel, et al. (författare)
  • Important role of p-selectin for leukocyte recruitment, hepatocellular injury, and apoptosis in endotoxemic mice.
  • 2004
  • Ingår i: Clinical and Diagnostic Laboratory Immunology. - : American Society for Microbiology. - 1071-412X. ; 11:1, s. 56-62
  • Tidskriftsartikel (refereegranskat)abstract
    • Leukocyte recruitment in the liver includes a two-step procedure in which selectin-dependent leukocyte rolling is a prerequisite for subsequent CD18-dependent leukocyte firm adhesion in postsinusoidal venules. However, the roles of the individual selectins in leukocyte rolling and adhesion, hepatocellular injury, and apoptosis remain elusive. Therefore, we examined the pathophysiological role of P-, E-, and L-selectin in male C57BL/6 mice challenged with lipopolysaccharide (LPS) and D-galactosamine (Gal) by use of intravital microscopy of the liver microcirculation. In control animals, administration of LPS-Gal provoked reproducible hepatic damage, including marked increases of leukocyte recruitment, liver enzymes, and hepatocyte apoptosis and reduced sinusoidal perfusion. Interestingly, pretreatment with an anti-P-selectin antibody (RB40.34) markedly reduced leukocyte rolling and firm adhesion by 65 and 71%, respectively. Moreover, interference with P-selectin function significantly improved sinusoidal perfusion and reduced the increase in liver enzymes by 49 to 84% in endotoxemic mice. Moreover, the activity of caspase-3 and the number of apoptotic hepatocytes were significantly reduced by 55 and 54%, respectively, in RB40.34-treated animals. In contrast, administration of an anti-E-selectin antibody (10E9.6) and an anti-L-selectin antibody (Mel-14) did not protect against endotoxin-induced leukocyte responses or hepatic injury. In conclusion, our novel findings document a principal role of P-selectin in mediating leukocyte rolling, a precondition to the subsequent firm adhesion of leukocytes in liver injury. Furthermore, our novel data demonstrate that inhibition of P-selectin function reduces hepatocellular injury and apoptosis, suggesting a causal relationship between leukocyte recruitment on one hand and hepatocellular injury and apoptosis on the other hand. Based on these findings, it is suggested that P-selectin may be an important therapeutic target in endotoxin-induced liver injury.
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7.
  • Klintman, Daniel, et al. (författare)
  • Leukocyte recruitment in hepatic injury: selectin-mediated leukocyte rolling is a prerequisite for CD18-dependent firm adhesion.
  • 2002
  • Ingår i: Journal of Hepatology. - : Elsevier. - 0168-8278. ; 36:1, s. 53-59
  • Tidskriftsartikel (refereegranskat)abstract
    • Background/Aims: This study was designed to examine the role of selectins and CD18 in leukocyte recruitment in hepatic injury induced by tumor necrosis factor-alpha (TNF-alpha) and galactosamine (Gal) in vivo.Methods: Intravital fluorescence microscopy of the hepatic microcirculation was used to quantify leukocyte-endothelium interactions provoked by 24 h of systemic TNF-alpha/Gal challenge in rats. Hepatic injury was evaluated with liver enzymes.Results: When administered after 24 h of TNF-alpha/Gal challenge, fucoidan, a selectin-function inhibitor, reduced leukocyte rolling by 69%, whereas firm adhesion was unaltered. In contrast, passive immunization against CD18 decreased leukocyte adhesion by 60%, whereas rolling remained unchanged. Notably, when administered prior to TNF-alpha/Gal, fucoidan attenuated both leukocyte rolling and adhesion, by 57 and 69%, respectively. Pretreatment with an anti-CD18 antibody decreased TNF-alpha/Gal-induced rolling and firm adhesion by 25 and 90%, respectively. Moreover, pretreatment with fucoidan and the anti-CD18 antibody both protected against TNF-alpha/Gal-induced increases in liver enzymes. For example, the pretreatments reduced alanine aminotransferase by 59 and 87%, respectively.Conclusions: Our data suggest that TNF-alpha/Gal-induced leukocyte rolling is selectin-mediated and a precondition for CD18-dependent firm adhesion in hepatic venules. Thus, reducing leukocyte recruitment by inhibition of selectins or CD18 may be useful to control TNF-alpha-induced liver injury.
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8.
  • Klintman, Daniel, et al. (författare)
  • Protective effect of Linomide on TNF-alpha-induced hepatic injury.
  • 2002
  • Ingår i: Journal of Hepatology. - : Elsevier. - 0168-8278. ; 36:2, s. 226-232
  • Tidskriftsartikel (refereegranskat)abstract
    • Background/Aims: Linomide is an immunomodulator that ameliorates several autoimmune and inflammatory diseases. We assessed the effect of Linomide on microvascular perfusion failure, leukocyte recruitment and hepatocellular injury induced by tumor necrosis factor alpha (TNF-alpha) and D-Galactosamine (Gal).Methods: After 3 days of Linomide pretreatment (1, 10 and 100mg/kg/day), rats were challenged with TNF-alpha/Gal for 24h. Microvascular perfusion, leukocyte--endothelium interactions in hepatic postsinusoidal venules and leukocyte sequestration in sinusoids were evaluated using intravital microscopy. Liver enzymes were measured spectrophotometrically.Results: Challenge with TNF-alpha/Gal significantly reduced sinusoidal perfusion, and increased leukocyte rolling, adhesion and liver enzymes. Interestingly, pretreatment with Linomide (10 and 100mg/kg/day) significantly reduced TNF-alpha/Gal-induced leukocyte rolling by 65 and 63%, and leukocyte adhesion by 87 and 84%, respectively. Moreover, Linomide (10 and 100mg/kg/day) decreased sinusoidal sequestration of leukocytes by 71 and 51%, and markedly improved sinusoidal perfusion. Moreover, Linomide reduced aspartate aminotransferase by 87--97%, and alanine aminotransferase by 79--96%. However, Linomide had no protective effect when administered concomitantly with TNF-alpha/Gal.Conclusions: These data demonstrate a dose-dependent inhibitory effect of Linomide on perfusion failure, leukocyte recruitment and hepatocellular injury provoked by TNF-alpha. Indeed, these findings suggest that Linomide may be an effective substance for protection of the liver in sepsis.
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  • Li, Xiang, et al. (författare)
  • Critical role of CXC chemokines in endotoxemic liver injury in mice.
  • 2004
  • Ingår i: Journal of Leukocyte Biology. - : John Wiley and Sons Ltd. - 1938-3673. ; 75:3, s. 443-452
  • Tidskriftsartikel (refereegranskat)abstract
    • Tissue accumulation of leukocytes constitutes a rate-limiting step in endotoxin-induced tissue injury. Chemokines have the capacity to regulate leukocyte trafficking. However, the role of CXC chemokines, i.e., macrophage inflammatory protein-2 (MIP-2) and cytokine-induced neutrophil chemoattractant (KC), in leukocyte recruitment, microvascular perfusion failure, cellular injury, and apoptosis in the liver remains elusive. Herein, mice were challenged with lipopolysaccharide (LPS) in combination with D-galactosamine, and intravital microscopy of the liver microcirculation was conducted 6 h later. It was found that immunoneutralization of MIP-2 and KC did not reduce LPS-induced leukocyte rolling and adhesion in postsinusoidal venules. In contrast, pretreatment with monoclonal antibodies against MIP-2 and KC abolished (83% reduction) extravascular recruitment of leukocytes in the livers of endotoxemic mice. Notably, endotoxin challenge increased the expression of CXC chemokines, which was mainly confined to hepatocytes. Moreover, endotoxin-induced increases of liver enzymes and hepatocellular apoptosis were decreased by more than 82% and 68%, respectively, and sinusoidal perfusion was restored in mice passively immunized against MIP-2 and KC. In conclusion, this study indicates that intravascular accumulation of leukocytes in the liver is independent of CXC chemokines in endotoxemic mice. Instead, our novel data suggest that CXC chemokines are instrumental in regulating endotoxin-induced transmigration and extravascular tissue accumulation of leukocytes. Indeed, these findings demonstrate that interference with MIP-2 and KC functions protects against septic liver damage and may constitute a potential therapeutic strategy to control pathological inflammation in endotoxemia.
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