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Pathological Role (pathological + role)
Selected AbstractsPathological Role of Aquaporin-2 in Impaired Water Excretion and HyponatremiaJOURNAL OF NEUROENDOCRINOLOGY, Issue 4 2004S. Ishikawa Abstract In the syndrome of inappropriate secretion of antidiuretic hormone (SIADH), inappropriately elevated secretion of vasopressin can result in a reduction of antidiuretic efficacy: a phenomenon known as ,vasopressin escape'. We compared experimental SIADH with 1-deamino-8- d -arginine vasopressin (dDAVP)-excess rats, where both groups received continuous subcutaneous administration of dDAVP by osmotic minipump but the SIADH rats also received a liquid diet that induced hyponatraemia. The SIADH rats, but not the dDAVP excess rats, showed a marked attenuation of urinary concentrating ability. Vasopressin V2 receptor binding capacity and mRNA expression were similar between the two groups, but the SIADH rats showed a diminished up-regulation of aquaporin-2 (AQP-2) mRNA and protein expression. These findings indicate the presence of tonicity-response regions in the AQP-2 promoter gene, and that either hypervolemia or hypotonicity may attenuate the postreceptor signalling of vasopressin in renal collecting duct cells in SIADH rats. [source] Prediabetes and the big baby,DIABETIC MEDICINE, Issue 1 2008D. R. Hadden Abstract The concept of prediabetes has come to the fore again with the worldwide epidemic of Type 2 diabetes. The careful observations of W. P. U. Jackson and his colleagues in Cape Town, South Africa 50 years ago still deserve attention. Maternal hyperglycaemia cannot be the only cause of fetal macrosomia, and the pathophysiological reason for the unexplained stillbirth in late diabetic pregnancy still eludes us. The biochemical concepts of ,facilitated anabolism' and ,accelerated starvation' were developed by Freinkel as explanations of the protective mechanisms for the baby during the stresses of pregnancy. Some of these nutritional stresses may also occur in the particular form of early childhood malnutrition known in Africa as kwashiorkor, where subcutaneous fat deposition, carbohydrate intolerance, islet hyperplasia and sudden death may follow a period of excess carbohydrate and deficient protein intake. Different feeding practices in different parts of the world make comparisons uncertain, but there is evidence for insulin resistance in both the macrosomic fetus of the hyperglycaemic mother and in the child with established kwashiorkor. These adaptive changes in early development may play both a physiological and a pathological role. Worldwide studies of hyperglycaemia in pregnancy are gradually establishing acceptable diagnostic criteria, appropriate screening procedures and an evidence base for treatment. Nevertheless the challenge of prediabetes and the big baby is still with us,in Jackson's words,,diabetes mellitus is a fascinating condition,the more we know about it the less we understand it'. [source] Interleukin-17 as a new marker of severity of acute hepatic injuryHEPATOLOGY RESEARCH, Issue 4 2007Yuki Yasumi Aim:, To determine cytokines associated with the progression of acute hepatic injury (AHI), we comprehensively evaluated the serum levels of 17 cytokines. Methods:, We simultaneously measured serum levels of 17 cytokines on admission using a newly developed suspension array protein assay system in 51 patients with AHI, including 15 conventional AHI (CAHI), 15 severe AHI (SAHI) and 21 fulminant hepatic failure (FHF). Results:, Interleukin (IL)-6, IL-8 and IL-17 levels were significantly different among the three disease types as determined by one-way analysis of variance, and only the IL-17 level showed a significant elevation in SAHI and FHF than in CAHI. Namely, the IL-17 levels in SAHI and FHF patients were 4.4 (2.0,11.0) (mean [1 .s.d. range]) and 5.6 (2.0,18.5) pg/mL, respectively, whereas all CAHI patients showed levels lower than the lower limit of detection (2.0 pg/mL). In multiple regression analysis for each factor of model for end-stage liver disease (MELD) score, only IL-10 level was selected as the significant independent variable for total bilirubin level, only IL-17 level for prothrombin time, and TNF-, and IL-1, levels for creatinine level. Conclusion:, These data suggest the usefulness of serum IL-17 level in evaluating the severity of AHI, thus emphasizing the necessity for the basic investigation of the pathological role of IL-17 in acute hepatitis. [source] Activator protein-1 signalling pathway and apoptosis are modulated by poly(ADP-ribose) polymerase-1 in experimental colitisIMMUNOLOGY, Issue 4 2004Basilia Zingarelli Summary Poly(ADP-ribose) polymerase-1 (PARP-1) is activated in response to DNA injury in the nucleus of eukaryotic cells and has been implicated in intestinal barrier dysfunction during inflammatory bowel diseases. In this study we investigated whether PARP-1 may regulate the inflammatory response of experimental colitis at the level of signal transduction mechanisms. Mice genetically deficient of PARP-1 (PARP-1,/,) and wild-type littermates were subjected to rectal instillation of trinitrobenzene sulphonic acid (TNBS). Signs of inflammation were monitored for 14 days. In wild-type mice, TNBS treatment resulted in colonic ulceration and marked apoptosis, which was associated with decreased colon content of the antiapoptotic protein Bcl-2, whereas the proapoptotic Bax was unchanged. Elevated levels of plasma nitrate/nitrite, metabolites of nitric oxide (NO), were also found. These inflammatory events were associated with activation of c-Jun-NH2 terminal kinase (JNK), phosphorylation of c-Jun and activation of the nuclear transcription factor activator protein-1 (AP-1) in the colon. In contrast, PARP-1,/, mice exhibited a significant reduction of colon damage and apoptosis, which was associated with increased colonic expression of Bcl-2 and lower levels of plasma nitrate/nitrite when compared to wild-type mice. Amelioration of colon damage was associated with a significant reduction of the activation of JNK and reduction of the DNA binding of AP-1. The data indicate that PARP-1 exerts a pathological role in colitis possibly by regulating the early stress-related transcriptional response through a positive modulation of the AP-1 and JNK pathways. [source] Extracorporeal photopheresis reduces the number of mononuclear cells that produce pro-inflammatory cytokines, when tested ex-vivoJOURNAL OF CLINICAL APHERESIS, Issue 4 2002John Bladon Abstract Extracorporeal photopheresis (ECP) has been shown to be clinically effective in the treatment of many T cell,mediated conditions. ECP's mechanism of action includes the induction of apoptosis and the release of pro-inflammatory cytokines. Recently, we have observed early lymphoid apoptosis, detectable immediately post ECP. We were interested to determine what influence ECP has on pro-inflammatory cytokine secretion at this early pre-infusion stage. Samples from 6 cutaneous T cell lymphoma (CTCL) and 5 graft versus host disease (GvHD) patients were taken pre ECP and immediately post ECP, prior to re-infusion. Following separation, the PBMCs were added to a cell culture medium and stimulated with PMA, Ionomycin, and Brefeldin A for 6 hours. Using flow cytometry, intracellular cytokine expression of IFN, and TNF, was determined in the T cell population. The monocytes were evaluated for IL6, IFN,, IL12, and TNF,. For both patient groups, the number of IFN,-expressing T cells fell significantly at re-infusion, whilst both T cell- and monocyte-expressing TNF, levels were reduced at re-infusion. All other cytokines tested showed no significant change post ECP. For GvHD, pro-inflammatory cytokines have a pathological role. Their down-regulation may have a direct clinical benefit. However, the reduction in the number of IFN,- and TNF,-expressing mononuclear cells means, at this early stage, it is unlikely that these cytokines assist in the removal of the malignant Th2 cells present in CTCL. J. Clin. Apheresis 17:177,182, 2002. © 2002 Wiley-Liss, Inc. [source] Postinjury vascular intimal hyperplasia in mice is completely inhibited by CD34+ bone marrow-derived progenitor cells expressing membrane-tethered anticoagulant fusion proteinsJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 10 2006D. CHEN Summary.,Background:,Coagulation proteins promote neointimal hyperplasia and vascular remodelling after vessel injury, but the precise mechanisms by which they act in vivo remain undetermined. Objectives:,This study, using an injury model in which the neointima is derived from bone marrow (BM)-derived cells, compared inhibition of tissue factor or thrombin on either BM-derived or existing vascular smooth muscle cells. Methods:,Two transgenic (Tg) mouse strains expressing membrane-tethered tissue factor pathway inhibitor (TFPI) or hirudin (Hir) fusion proteins driven by an , smooth muscle actin (SMA) promoter were generated (, -TFPI-Tg and , -Hir-Tg) and the phenotype after wire-induced endovascular injury was compared with that in wild-type (WT) controls. Results:,WT mice developed progressive neointimal expansion, whereas injury in either Tg was followed by repair back to a preinjured state. This was also seen when WT mice were reconstituted with BM from Tg mice but not when Tgs were reconstituted with WT BM, in which injury was followed by slowly progressive neointimal expansion. Injection of CD34+ cells from Tg mice into injured WT mice resulted in the accumulation of fusion protein-expressing cells from day 3 onwards and an absence of neointimal hyperplasia in those areas. Conclusions:,Neointimal development after wire-induced endovascular injury in mice was completely inhibited when BM-derived cells infiltrating the damaged artery expressed membrane tethered anticoagulant fusion proteins under an , -SMA promoter. These findings enhance our understanding of the pathological role that coagulation proteins play in vascular inflammation. [source] Inflammatory cytokines in glomerulonephritisNEPHROLOGY, Issue 2002RC ATKINS SUMMARY: The importance of various inflammatory cytokines in mediating renal disease is now recognized, and the potential for the use of cytokine blockade as a therapeutic intervention is under active investigation. Studies in rat anti-glomerular basement membrane (GBM) disease model showed that antagonism of the proinflammatory cytokine IL-1 inhibited induction of glomerulonephritis, and prevented progression of established disease. A second cytokine Tumour Necrosis Factor-alpha (TNF-,) had similar proinflammatory effects to IL-1 in this model. Blocking the actions of both cytokines together, however, had no added benefit. Another cytokine Macrophage Migration Inhibitory Factor (MIF) has been shown to override the anti-inflammatory effects of corticosteriods. Renal MIF is markedly up-regulated in rat anti-GBM disease and blocking studies have demonstrated MIF plays a pathological role in mediating renal injury in this model. the importance of MIF in glomerulonephritis has been demonstrated by the fact that MIF is produced locally within the kidney, that it reflects the severity of the cellular immune response, and can be measured in the urine. Macrophage Migration Inhibitory Factor is up-regulated in human glomerular disease and correlates with loss of renal function and is thus a potential target for therapy for human glomerulonephritis. Thus, the inflammatory cytokines, IL 1, TNF-, and MIF each play a role in the immune/inflammatory process in glomerulonephritis. Blocking their action reduces disease and cytokine blocking agents have therapeutic potential. [source] ABSTRACTS: 1 Implication of soluble receptors of VEGF, sVEGFR-1 and sVEGFR-2, in angiogenesisAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 1 20082TH -6TH JUNE 2008 TOP SELECTED ABSTRACTS, 4TH EMBIC SUMMER SCHOOL, BARCELONA, SPAIN Introduction:, sVEGFR-1 and sVEGFR-2 are soluble forms of the membrane-bound receptors of VEGF. sVEGFR-1 is detected in plasma of pre-eclamptic women, during ischemia and in some cancer cases. sVEGFR-2, was recently detected in plasma of healthy people, in leukaemia and in systemic erythematosus lupus cases. sVEGFR-1 has anti-angiogenic properties in vitro and in vivo but sVEGFR-2 remains uncharacterized and its physiological or pathological role is still unknown. Material and Methods:, The aim of this study was to understand and to characterize the role of sVEGFR2 in angiogenesis and in endothelial function. Results:, In aortic ring assay, an ex vivo model of angiogenesis, sVEGFR1 and sVEGFR2 were able to abolish VEGF-induced angiogenesis. However, when used alone, they induced the formation of a "network", supposed to be vascular in visible microscopy. As they were able to abolish the effect of VEGF on endothelial function but showed no direct effect alone, we performed an immuno-staining of the "vascular network" induced by the soluble receptors. It showed that there were a few endothelial cells but mostly pericytes/smooth muscle cells (PC/SMC). Our first in vitro experiments on PC/SMC showed that sVEGFR-1 and sVEGFR-2 were able to promote the migration of PC/SMC, only in presence of endothelial cells. Conclusions:, Our results evidence that sVEGFR1 and sVEGFR2 inhibit VEGF-induced angiogenesis in a similar way. However, they have also a direct effect on PC/SMC, promoting their migration. Our results suggest that these soluble receptors could act, not only on endothelial cells themselves, but by a direct effect on PC/SMC too. These results contribute to identify factors by which it could be possible to regulate the balance between pro-angiogenic and anti-angiogenic factors, especially in the case of the anti-VEGF drugs used now as anti-cancer therapies in clinics, where a transient "normalization" of the vessels is observed. [source] Transgenic mice for Cre-inducible overexpression of the oncogenes c-MYC and Pim-1 in multiple tissuesGENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 10 2006Meejeon Roh Abstract The transcription factor c-MYC and the serine-threonine kinase Pim-1 have multiple roles in development and cancer, including in lymphomagenesis and prostate tumorigenesis. In some cancers, MYC and Pim-1 oncogenes are co-expressed and show marked cooperativity. To facilitate the analysis of the pathological roles of MYC and Pim-1 in specific cell types and developmental stages, we generated mice carrying Cre-inducible MYC/Pim-1 transgenes. The mice carry a constitutively expressed lacZ marker and silent MYC/Pim-1 genes. Cre-mediated recombination results in deletion of the lacZ marker and concurrent activation of the MYC/Pim-1 transgene. In addition, the Pim-1 mice harbor an alkaline phosphatase gene as a positive marker for recombination. Mouse lines for each gene were established, which show distinct patterns of expression in multiple tissues. In vivo recombination was confirmed for all lines by breeding to Cre transgenic mice. These mice provide a valuable resource for investigating the significance of MYC and Pim-1 overexpression in various tissues. genesis 44:447,453, 2006. © 2006 Wiley-Liss, Inc. [source] Sequence-specific gene silencing in murine muscle induced by electroporation-mediated transfer of short interfering RNATHE JOURNAL OF GENE MEDICINE, Issue 1 2004Tsunao Kishida Abstract Background Post-genomic biomedical research requires efficient techniques for functional analyses of poorly characterized genes in living organisms. Sequence-specific gene silencing in mammalian organs may provide valuable information on the physiological and pathological roles of predicted genes in mammalian systems. Here, we attempted targeted gene knockdown in vivo in murine skeletal muscle through the electroporation-mediated transfer of short interfering RNA (siRNA). Methods siRNA duplexes corresponding to the firefly luciferase (Luc), green fluorescent protein (GFP), or glyceraldehyde-3-phosphate dehydrogenase (GAPD) genes were delivered by electroporation into the tibial muscle of normal or enhanced GFP (EGFP) transgenic mice. Plasmid vectors carrying the Luc, hRluc or ,-galactosidase (,-gal) reporter genes were also delivered. The Luc and hRluc activities in the muscle lysates were assayed. The EGFP and GAPD expression was detected by fluorescence microscopic observation and RT-PCR, respectively. Results When Luc-specific siRNA was co-delivered with the Luc expression vector into the tibial muscle, the reporter gene expression was markedly suppressed (less than 1% of the control level) for 5 days. As little as 0.05 µg of siRNA almost completely blocked the reporter gene expression from 10 µg of the plasmid. To examine whether siRNA can also suppress expression of an endogenous gene, transgenic mice carrying the EGFP gene received intramuscular transfection of a mixture of ,-gal plasmid and GFP-specific siRNA. ,-Gal-positive cells failed to express detectable levels of EGFP, while EGFP expression was not inhibited in control mice that received nonspecific siRNA. Expression of GAPD was also suppressed by the specific siRNA. Conclusions The present system may provide a useful means of phenotypic analysis of genetic information in mammalian organs for basic research as well as therapeutic molecular targeting in the post-genomic era. Copyright © 2003 John Wiley & Sons, Ltd. [source] | |||||||||||||