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Popliteal Lymph Node (popliteal + lymph_node)
Selected AbstractsPopliteal lymph node assay: facts and perspectivesJOURNAL OF APPLIED TOXICOLOGY, Issue 6 2005Guillaume Ravel Abstract The popliteal lymph node assay (PLNA) derives from the hypothesis that some supposedly immunemediated adverse effects induced by certain pharmaceuticals involve a mechanism resembling a graft-versus-host reaction. The injection of many but not all of these compounds into the footpad of mice or rats produces an increase in the weight and/or cellularity of the popliteal lymph node in the treated limb (direct PLNA). Some of the compounds known to cause these adverse effects in humans, however, failed to induce a positive PLNA response, leading to refinements of the technique to include pretreatment with enzyme inducers, depletion of CD4+ T cells or additional endpoints such as histological examination, lymphocyte subset analysis and cytokine fingerprinting. Alternative approaches have been used to improve further the predictability of the assay. In the secondary PLNA, the test compound is injected twice in order to illicit a greater secondary response, thus suggesting a memory-specific T cell response. In the adoptive PLNA, popliteal lymph node cells from treated mice are injected into the footpad of naive mice; a marked response to a subsequent footpad challenge demonstrates the involvement of T cells. Finally, the reporter antigens TNP-Ficoll and TNP-ovalbumin are used to differentiate compounds that induce responses involving neo-antigen help or co-stimulatory signals (modified PLNA). The PLNA is increasingly considered as a tool for detection of the potential to induce both sensitization and autoimmune reactions. A major current limitation is validation. A small inter-laboratory validation study of the direct PLNA found consistent results. No such study has been performed using an alternative protocol. Other issues include selection of the optimal protocol for an improved prediction of sensitization vs autoimmunity, and the elimination of false-positive responses due to primary irritation. Finally, a better understanding of underlying mechanisms is essential to determine the most relevant endpoints. The confusion resulting from use of the PLNA to predict autoimmune-like reactions as well as sensitization should be clarified. Interestingly, most drugs that were positive in the direct PLNA are also known to cause drug hypersensitivity syndrome in treated patients. This observation is expected to open new avenues of research. Copyright © 2005 John Wiley & Sons, Ltd. [source] Recanalization of the Collecting Lymphatics in Rabbit Hind LegMICROCIRCULATION, Issue 5 2006FUMITAKA IKOMI ABSTRACT Objective: This study was designed to examine whether mature collecting lymphatics can regenerate in the adult tissue or not. Materials and Methods: The X-ray lymphograms were used to detect network of the collecting lymphatics in rabbit hind leg. Regeneration of the lymphatics was observed after surgical removal of the popliteal lymph node or a part of the popliteal afferent lymphatic. Structure and mechanical properties of the lymphatics were also examined by light and electron microscopes and in vitro functional experiments. Results: One week after removal of the lymph node, only an afferent lymphatic and a deposit of the contrast medium at the popliteal region were observed. Four weeks after the removal, the connection of the afferent and efferent lymphatics at the popliteal region, and collateral lymphatics were present in the leg. Further, 4 weeks after 1-mm excisions of a part of the lymphatic, recanalization was observed between the central and peripheral cut ends of the lymphatic but not after 3- and 10-mm excisions. Endothelial cells and smooth muscle cells could be observed by electron microscope, and contractile proteins, and alpha-smooth muscle actin SM1 and SM2 were immunofluorescently detected in both intact and the regenerated lymphatic walls. In both lymphatics, norepinephrine and acetylcholine induced dose-dependent constriction and dilation of the vessels, respectively. Conclusion: The present study demonstrated that mature collecting lymphatics are able to regenerate in the adult tissues. [source] Near-infrared lymphatic imaging demonstrates the dynamics of lymph flow and lymphangiogenesis during the acute versus chronic phases of arthritis in miceARTHRITIS & RHEUMATISM, Issue 7 2010Quan Zhou Objective To develop an in vivo imaging method to assess lymphatic draining function in the K/BxN mouse model of inflammatory arthritis. Methods Indocyanine green, a near-infrared fluorescent dye, was injected intradermally into the footpads of wild-type mice, mouse limbs were illuminated with an 806-nm near-infrared laser, and the movement of indocyanine green from the injection site to the draining popliteal lymph node (LN) was recorded with a CCD camera. Indocyanine green near-infrared images were analyzed to obtain 5 measures of lymphatic function across time. Images of K/BxN arthritic mice and control nonarthritic littermates were obtained at 1 month of age, when acute joint inflammation commenced, and again at 3 months of age, when joint inflammation became chronic. Lymphangiogenesis in popliteal LNs was assessed by immunochemistry. Results Indocyanine green and its transport within lymphatic vessels were readily visualized, and quantitative measures were derived. During the acute phase of arthritis, the lymphatic vessels were dilated, with increased indocyanine green signal intensity and lymphatic pulses, and popliteal LNs became fluorescent quickly. During the chronic phase, new lymphatic vessels were present near the foot. However, the appearance of indocyanine green in lymphatic vessels was delayed. The size and area of popliteal LN lymphatic sinuses progressively increased in the K/BxN mice. Conclusion Our findings indicate that indocyanine green near-infrared lymphatic imaging is a valuable method for assessing the lymphatic draining function in mice with inflammatory arthritis. Indocyanine green,near-infrared imaging of K/BxN mice identified 2 distinct lymphatic phenotypes during the acute and chronic phase of inflammation. This technique can be used to assess new therapies for lymphatic disorders. [source] Disseminated haemangiosarcoma in an Eastern barred bandicoot (Perameles gunnii)AUSTRALIAN VETERINARY JOURNAL, Issue 9 2000KB BODLEY A captive adult male Eastern barred bandicoot (Perameles gunnii) presented with three palpable subcutaneous masses in November 1998. A diagnosis of haemangiosarcoma was made based on histological examination of one excised mass. Euthanasia of the animal was performed 11 days postsurgery and a proliferative lesion in the paralumbar musculature and similar, smaller proliferative lesions surrounding the right popliteal lymph node and in the ventricular wall of the heart were found. Metastatic lesions were found in the liver and lung. The histological features of the neoplastic tissues supported the diagnosis of a poorly differentiated, disseminated haemangiosarcoma. This is the first reported case of haemangiosarcoma in the Eastern barred bandicoot. [source] Phenotypic profile and functional characterization of rat lymph node-derived ,, T cells: implication in the immune response to cytomegalovirusIMMUNOLOGY, Issue 2 2003Larissa Dyugovskaya Summary ,, T cells are unique, and their localization at sites of infection is considered critical in immune defence. We demonstrate the accumulation of ,, T cells in rat regional popliteal lymph nodes (PLNi) starting 2 days after inoculation of cytomegalovirus (CMV) into the footpad. Early-appearance PLNi ,, T cells significantly inhibited plaque development and the spread of CMV infection. These ,, T cells were negative for CD4 and CD8beta receptors, proliferated in response to interleukin-2 (IL-2) and contained high levels of interferon-, (IFN-,), the appearance of which correlated with the curing of fibroblasts from virus infection. The addition of anti-IFN-, abolished the ability of fibroblast monolayers to be cured from CMV infection. In contrast, this protection was not abolished by the addition of anti-rat IL-2 or anti-rat TNF-,, or by the depletion of NKR-P1-bearing cells within ,, T cells. In addition, the present study shows that while ,, T cells derived from naive and CMV-infected rats are able to kill both YAC-1 targets and CMV-infected syngeneic fibroblasts in vitro, only the latter are able to clear CMV-infected fibroblast monolayers. Finally, our data suggest that the expression of NKR-P1 by ,, T cells is critical for cytotoxicity, but its contribution to the curing from CMV infection was limited. [source] Reduced apoptosis in BALB/c mice infected with Heligmosomoides polygyrusPARASITE IMMUNOLOGY, Issue 6 2007M. DOLIGALSKA SUMMARY We evaluated levels of apoptosis and the immune response ex vivo in BALB/c mice infected with Heligmosomoides polygyrus. Cell proliferation, apoptosis and cytokine production were measured in mesenteric lymph nodes (MLN) without exposure to H. polygyrus antigens in culture. The inhibited apoptosis and cytokine production reported might reflect a state of cell hyporesponsiveness in the prepatent phase of infection. These changes were accompanied by changes in the percentage of CD4+ cells in MLN and popliteal lymph nodes (PLN). The prolonged reduction in apoptosis coexisted with induced cell proliferation, elevated TNF-,, IL-12p70, IFN-,, IL-6, IL-10 and TGF-, synthesis, but lowered IL-4 and IL-2 levels. In the chronic phase of infection an increasing production of IFN-,, monocyte chemotactic protein-1 (MCP-1), IL-10 and TGF-, with decreasing concentrations of other cytokines resulted in restored apoptosis. The cytokine response in serum showed moderate production of TNF-,, temporary involvement of IL-12p70, induction of IFN-, and IL-10 synthesis, as well as growing IL-6 and MCP-1 production. It is suggested that a synchronized synthesis of distinct cytokines is accompanied by different levels of inhibited apoptosis during the prepatent and chronic phases of H. polygyrus infection in BALB/c mice. We suggest that immunosuppression provoked by the nematode is not the outcome of parasite-induced apoptosis, but rather results from a hyporesponsiveness experienced by cells during H. polygyrus infection. [source] | ||||||||||