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Target Tissues (target + tissue)
Selected AbstractsDistributions of estrogen receptors alpha and beta in sympathetic neurons of female rats: Enriched expression by uterine innervationDEVELOPMENTAL NEUROBIOLOGY, Issue 1 2002Elena V. Zoubina Abstract Estrogen modulates many features of the sympathetic nervous system, including cell numbers and ganglion synapses, and can induce uterine sympathetic nerve degeneration. However, distributions of estrogen receptors , and , within sympathetic neurons have not been described, and their regulation by target tissue or estrogen levels has not been explored. We used immunofluorescence and retrograde tracing to define estrogen receptor expression in sympathetic neurons at large in pre- and paravertebral ganglia and in those projecting to the uterine horns. Estrogen receptor , immunoreactivity was present in 29 ± 1%, while estrogen receptor , was expressed by 92 ± 1% of sympathetic neurons at large. The proportions of neurons expressing these receptors were comparable in the superior cervical and thoraco-lumbar paravertebral ganglia from T11 through L5, and in the suprarenal, celiac, and superior mesenteric prevertebral ganglia. Injections of FluoroGold into the uterine horns resulted in labeled neurons, with peak occurrences in T13, L1, and the suprarenal ganglion. Uterine-projecting neurons showed small but significantly greater incidence of estrogen receptor , expression relative to the neuronal population at large, whereas the proportion of uterine-projecting neurons with estrogen receptor ,-immunoreactivity was nearly threefold greater. Numbers of estrogen receptor-expressing neurons were not altered by acute estrogen administration. We conclude that the vast majority of sympathetic neurons express estrogen receptor , immunoreactive protein, whereas a smaller, presumably overlapping subset expresses the estrogen receptor ,. Expression of the latter apparently can be enhanced by target-mediated mechanisms. © 2002 Wiley Periodicals, Inc. J Neurobiol 52: 14,23, 2002 [source] IL-23-driven encephalo-tropism and Th17 polarization during CNS-inflammation in vivoEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 7 2009Gabor Gyülvészi Abstract IL-23 but not IL-12 is essential for the development of autoimmune tissue inflammation in mice. Conversely, IL-12 and IL-23 impact on the polarization of Th1 and Th17 cells, respectively. While both polarized T helper populations can mediate autoimmune inflammation, their redundancy in the pathogenesis of EAE indicates that IL-23 exerts its crucial influence on the disease independent of its T helper polarizing capacity. To study the impact of IL-23 and IL-12 on the behavior of encephalitogenic T cells in vivo, we generated BM-chimeric mice in which we can trace individual populations of IL-23 or IL-12 responsive T helper cells during EAE. We observed that T cells, which lack IL-12R,1 (no IL-12 and IL-23 signaling), fail to invade the CNS and do not acquire a Th17 phenotype. In contrast, loss of IL-12 signaling prevents Th1 polarization but does not prevent T-cell entry into the CNS. The loss of IL-12R engagement does not appear to alter T-cell expansion but leads to their accumulation in secondary lymphoid organs. We found that IL-23 licenses T cells to invade the target tissue and to exert their effector function, whereas IL-12 is critical for Th1 differentiation, but does not influence the pathogenic capacity of auto-reactive T helper cells in vivo. [source] Asymmetric bolaamphiphiles from vernonia oil designed for drug deliveryEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 1 2010Sarina Grinberg Abstract Throughout the ages, fats, oils and their chemical derivatives have been used in a variety of medical applications, but currently they are becoming important as components in drug delivery systems. Liposomes (vesicles from phospholipids) are among the lipid-based delivery systems that have been most extensively studied. However, targeting of liposomes to specific tissues is still problematic, and attempts to overcome these limitations include developments in nano-sized monolayer vesicles made of bolaamphiphiles (compounds containing two hydrophilic headgroups at each end of an alkyl chain). This paper describes bolaamphiphile synthesis and characterization of the nano-sized vesicles formed from the bolaamphiphiles with potential application for targeted drug delivery to the brain. The starting material for the synthesis is vernonia oil (or its fatty acids or methyl esters), which is a naturally epoxidized triacylglycerol obtained from the seeds of Vernonia galamensis. The targeting mechanism is based on the hydrolysis of the amphiphile's headgroup by an enzyme abundant in the target tissue, with subsequent release of the encapsulated drug at the target site. Preliminary experiments in mice demonstrated that the marker FITC-dextran, which normally does not penetrate the blood brain barrier, is delivered into the brain when encapsulated in these vesicles. [source] Maturation of postsynaptic nicotinic structures on autonomic neurons requires innervation but not cholinergic transmissionEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2002Sergio Kaiser Abstract Postsynaptic development at the neuromuscular junction depends on nicotinic transmission and secreted components from the presynaptic motor nerve terminal. Similarly, secreted components and synaptic activity are both thought to guide development of glutamatergic synapses in the CNS. Nicotinic synapses on chick ciliary neurons are structurally complex: a large presynaptic calyx engulfs the postsynaptic neuron and overlays a series of discrete mats of receptor-rich somatic spines tightly interwoven and folded against the soma. We used fluorescence imaging of ,7-containing nicotinic receptors and the spine constituent drebrin to monitor postsynaptic development. The results show that surgical disruption of the preganglionic input or removal of the ganglionic synaptic target tissue after synapses form in the ganglion does not disrupt the receptor-rich spine mats. Similarly, removal of the target tissue even prior to synapse formation in the ganglion does not prevent subsequent formation of the receptor clusters and associated spine constituents. Postsynaptic development is arrested, however, if normal innervation is prevented by ablating the preganglionic neurons prior to synapse formation. In this case the neurons express reduced levels of nicotinic receptors and cytoskeletal components and organize them only into early-stage clusters. Even low levels of residual innervation, however, can restore much of the normal postsynaptic receptor patterns. Chronic pharmacological blockade of cholinergic synaptic activity fails to replicate the effects of ablating the preganglionic nucleus. The results indicate that ciliary neurons are programmed to express postsynaptic components and can initiate clustering of ,7-containing receptors but need presynaptic guidance for maturation of the postsynaptic structure. [source] Frontiers and controversies in the pathobiology of vitiligo: separating the wheat from the chaffEXPERIMENTAL DERMATOLOGY, Issue 7 2009Raymond E. Boissy Abstract:, The pathogenesis of vitiligo is complex and not well understood. Genes play a role in all aspects of vitiligo pathogenesis, and studies are ongoing to identify these genes and understand their biology. There is a body of interlocking, compelling evidence supporting an autoimmune basis for most or all cases of generalized vitiligo. The development of an autoimmune disease generally involves three components; the immune system, environmental triggers and other exogenous precipitating factors, and the target tissue. In vitiligo, precipitating factors could induce melanocyte damage in genetically susceptible individuals and consequent cell death, loss of tolerance, and induction of melanocyte-directed autoimmunity. Future research will more precisely define the multiple biological events that regulate development of vitiligo. [source] The skin as a biofactory for systemic secretion of erythropoietin: potential of genetically modified keratinocytes and fibroblastsEXPERIMENTAL DERMATOLOGY, Issue 6 2008Frank Scheidemann Abstract Background:, The skin is an interesting target tissue for gene therapy applications because of its ready accessibility. One possibility would be to utilize the genetically modified skin as a biofactory secreting a systemically needed product, such as erythropoietin (EPO). Methods:, Keratinocytes (KC) and fibroblasts (FB) were transduced with a retroviral vector encoding human EPO. Gene transfer efficiency was assessed by real-time PCR analysis and flow cytometry of transduced cells. In addition, EPO synthesis and secretion were analysed by quantifying the amount of RNA and secreted protein in both monolayer cultures and skin equivalents (SE). Results:, When cultured as a monolayer, EPO-KC synthesized significantly more EPO than EPO-FB, as shown by quantitatively measuring the amount of secreted protein and RNA. This correlated with an increased EPO-vector incorporation in KC compared with FB, demonstrated by determining both the percentage of transduced cells and the average transgene copy number per cell. In addition, in transduced cell cultures enriched to equally high percentages of EPO+ cells, KC showed a higher activity of EPO secretion than FB. Finally, when assembled in a SE, EPO-KC secreted significantly higher amounts of EPO than EPO-FB, although reduced secretory activity of EPO-KC monolayers grown in high calcium concentrations suggested that in stratified epidermis differentiated KC secrete less EPO than non-differentiated KC. Conclusion:, In summary, while both transduced KC and FB are able to synthesize and secrete human EPO, KC show higher potential in serving as possible target cells for therapeutic substitution with EPO, probably because of improved transduction rates and increased secretory activity. [source] Advances and Applications of Biodegradable Elastomers in Regenerative MedicineADVANCED FUNCTIONAL MATERIALS, Issue 2 2010Maria Concepcion Serrano Abstract When elastomers were first proposed as useful materials for regenerative medicine a few decades ago, their high versatility and suitability for a diverse and wide range of in vivo applications could not have been predicted. Due to their ability to recover after deformation, these materials were first introduced in tissue engineering in an attempt to mimic the mechanical properties of the extracellular matrix. Furthermore, elastomeric characteristics have been described as important criteria for cell interaction by modulating cellular behavior. From soft to hard tissues, elastomers have demonstrated degradation, mechanical, and biocompatibility requirements in accordance with the target tissue. In this feature article, biodegradable synthetic polyester elastomers that have been reported in the literature are discussed, with special focus on those that show promise for in vivo tissue replacement. Their satisfactory performance in vivo shows the promise of elastomers for use in regenerative medicine. However, further investigation is required to demonstrate the prospect of elastomer-based therapies in clinical trials. [source] Nerve Repair: A Conducting-Polymer Platform with Biodegradable Fibers for Stimulation and Guidance of Axonal Growth (Adv. Mater.ADVANCED MATERIALS, Issue 43 200943/2009) Effective functional innervation of medical bionic devices, as well as re-innervation of target tissue in nerve and spinal cord injuries, requires a platform that can stimulate and orientate neural growth. Gordon Wallace and co-workers report on p. 4393 that conducting and nonconducting biodegradable polymers show excellent potential as suitable hybrid substrata for neural regeneration and may form the basis of electrically active conduits designed to accelerate nerve repair. [source] Aldehyde-Amine Chemistry Enables Modulated Biosealants with Tissue-Specific AdhesionADVANCED MATERIALS, Issue 32-33 2009Natalie Artzi The interfacial regions between PEG: dextran-based adhesive sealant and excised rat heart, lung, liver, and duodenum tissues exhibit three distinct domains; target tissue (red and blue), bulk material (green), and an adhesive regime interposed between the two. The variation in adhesive regime morphology when applied to different tissues provides a rational approach for the engineering of application-specific surgical sealants. [source] Memory T-cell trafficking: new directions for busy commutersIMMUNOLOGY, Issue 2 2010Federica M. Marelli-Berg Summary The immune system is unique in representing a network of interacting cells of enormous complexity and yet being based on single cells travelling around the body. The development of effective and regulated immunity relies upon co-ordinated migration of each cellular component, which is regulated by diverse signals provided by the tissue. Co-ordinated migration is particularly relevant to the recirculation of primed T cells, which, while performing continuous immune surveillance, need to promptly localize to antigenic sites, reside for a time sufficient to carry out their effector function and then efficiently leave the tissue to avoid bystander damage. Recent advances that have helped to clarify a number of key molecular mechanisms underlying the complexity and efficiency of memory T-cell trafficking, including antigen-dependent T-cell trafficking, the regulation of T-cell motility by costimulatory molecules, T-cell migration out of target tissue and fugetaxis, are reviewed in this article. [source] Original Article: Clinical Investigation: Anterior perirectal fat tissue thickness is a strong predictor of recurrence after high-intensity focused ultrasound for prostate cancerINTERNATIONAL JOURNAL OF UROLOGY, Issue 9 2010Makoto Sumitomo Objective: To evaluate if and why obesity affects the clinical outcome in patients undergoing high-intensity focused ultrasound (HIFU) treatment for prostate cancer (CaP). Methods: 115 patients who underwent HIFU treatment for localized CaP were categorized as obese, overweight or normal according to body mass index (BMI). The thickness of the anterior perirectal fat tissue (APFT) was measured by transrectal ultrasonography. Treatment was considered to have failed in the case of biochemical failure according to the Phoenix definition, positive follow-up biopsy or initiation of salvage therapy. Cox proportional hazards analyses were used to identify possible predictors for disease free survival (DFS), and an experimental fat tissue model was made to evaluate the ablation effect at the target tissue. Results: According to the classification by the Western Pacific Regional Office of WHO, 43 patients were of normal weight, 24 were overweight and 48 were obese. The BMI groups did not differ in Gleason score, prostate-specific antigen level at diagnosis or clinical stage. There were, however, significant correlations between BMI and prostate-specific antigen nadir (P < 0.001), and BMI and APFT thickness (P < 0.01). Multivariate analyses showed that BMI fails to be an independent predictor of DFS when APFT (P < 0.0001) is included as a variable. Conclusions: Our results suggest that APFT thickness, for which obesity could be a useful surrogate, might represent the causative factor for poor clinical outcome after transrectal HIFU treatment for CaP. [source] Adipose tissue gene expression in obese dogs after weight lossJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 3 2008V. Leray Summary Body weight (BW) mainly depends on a balance between fat storage (lipogenesis) and fat mobilization (lipolysis) in adipocytes. BW changes play a role in insulin resistance (IR), the inability of insulin target tissue to respond to physiological levels of insulin. This results in inhibition of lipogenesis and stimulation of lipolysis. Weight gain leads to IR whereas, weight loss improves insulin sensitivity (IS). The aim of this study was to evaluate the effect of weight loss and recovery of IS on the expression of genes involved in lipogenesis and lipolysis in weight losing dogs. Gene expression was studied in both subcutaneous and visceral adipose tissue. Obese dogs received a hypoenergetic low fat high protein diet (0.6 × NRC recommendation). Before and after weight loss, IS was assessed using the euglycaemic hyperinsulinaemic clamp. Gene expression of IRS-2, SREBP, intracellular insulin effectors, ACC, FAS, FABP, ADRP, PEPCK, lipogenesis key proteins, perilipin and HSL, lipolysis key proteins were quantified using real-time RT-PCR in subcutaneous and visceral fat. BW decreased from 15.2 ± 0.5 to 11.4 ± 0.4 kg (p < 0.05) over 78 ± 8 days. When obese, dogs were insulin resistant. After weight loss, IS was improved. In the subcutaneous adipose tissue, the expression of only the IRS-2 was increased. In the visceral adipose tissue, the expression of the genes involved in the lipogenesis was decreased whereas one of the genes implied in the lipolysis did not change. The expression profile of genes involved in lipid metabolism, as measured after weight loss, is indicative for a lower lipogenesis after weight loss than in obese dogs. Our results also confirm dramatic differences in the lipid metabolism of visceral and subcutaneous fat. They should be completed by comparing gene expression during weight losing and normal weight steady state. [source] Gold-Tip Electrodes,A New "Deep Lesion" Technology for Catheter Ablation?JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2005In Vitro Comparison of a Gold Alloy Versus Platinum, Iridium Tip Electrode Ablation Catheter Radiofrequency (RF) catheter ablation is widely used to induce focal myocardial necrosis using the effect of resistive heating through high-frequency current delivery. It is current standard to limit the target tissue,electrode interface temperature to a maximum of 60,70°C to avoid char formation. Gold (Au) exhibits a thermal conductivity of nearly four times greater than platinum (Pt,Ir) (3.17 W/cm Kelvin vs 0.716 W/cm Kelvin), it was therefore hypothesized that RF ablation using a gold electrode would create broader and deeper lesions as a result of a better heat conduction from the tissue,electrode interface and additional cooling of the gold electrode by "heat loss" to the intracardiac blood. Both mechanisms would allow applying more RF power to the tissue before the electrode,tissue interface temperature limit is reached. To test this hypothesis, we performed in vitro isolated liver and pig heart investigations comparing lesion depths of a new Au-alloy-tip electrode to standard Pt,Ir electrode material. Mean lesion depth in liver tissue for Pt,Ir was 4.33 ± 0.45 mm (n = 60) whereas Au electrode was able to achieve significantly deeper lesions (5.86 ± 0.37 mm [n = 60; P < 0.001]). The mean power delivered using Pt,Ir was 6.95 ± 2.41 W whereas Au tip electrode delivered 9.64 ± 3.78 W indicating a statistically significant difference (P < 0.05). In vitro pig heart tissue Au ablation (n = 20) increased significantly the lesion depth (Au: 4.85 ± 1.01 mm, Pt,Ir: 2.96 ± 0.81 mm, n = 20; P < 0.001). Au tip electrode again applied significantly more power (P < 0.001). Gold-tip electrode catheters were able to induce deeper lesions using RF ablation in vitro as compared to Pt,Ir tip electrode material. In liver and in pig heart tissue, the increase in lesion depth was associated with a significant increase in the average power applied with the gold electrode at the same level of electrode,tissue temperature as compared to platinum material. [source] Non-viral VEGF165 gene therapy , magnetofection of acoustically active magnetic lipospheres (,magnetobubbles') increases tissue survival in an oversized skin flap modelJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 3 2010Thomas Holzbach Abstract Adenoviral transduction of the VEGF gene in an oversized skin flap increases flap survival and perfusion. In this study, we investigated the potential of magnetofection of magnetic lipospheres containing VEGF165 -cDNA on survival and perfusion of ischemic skin flaps and evaluated the method with respect to the significance of applied magnetic field and ultrasound. We prepared perfluoropropane-filled magnetic lipospheres (,magnetobubbles') from Tween60-coated magnetic nanoparticles, Metafectene, soybean-oil and cDNA and studied the effect in an oversized random-pattern-flap model in the rats (n= 46). VEGF-cDNA-magnetobubbles were administered under a magnetic field with simultaneously applied ultrasound, under magnetic field alone and with applied ultrasound alone. Therapy was conducted 7 days pre-operative. Flap survival and necrosis were measured 7 days post-operatively. Flap perfusion, VEGF-protein concentration in target and surrounding tissue, formation and appearance of new vessels were analysed additionally. Magnetofection with VEGF-cDNA-magnetobubbles presented an increased flap survival of 50% and increased flap perfusion (P < 0.05). Without ultrasound and without magnetic field, the effect is weakened. VEGF concentration in target tissue was elevated (P < 0.05), while underlying muscle was not affected. Our results demonstrate the successful VEGF gene therapy by means of magnetobubble magnetofection. Here, the method of magnetofection of magnetic lipospheres is equally efficient as adenoviral transduction, but has a presumable superior safety profile. [source] 1,25(OH)2 -vitamin D3 induces translocation of the vitamin D receptor (VDR) to the plasma membrane in skeletal muscle cellsJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 1 2002Daniela Capiati Abstract 1,25-dihydroxy-vitamin D3 (1,25(OH)2D3), the hormonally active form of vitamin D3, acts through two different mechanisms. In addition to regulating gene expression via the specific intracellular vitamin D receptor (VDR), 1,25(OH)2D3 induces rapid, non-transcriptional responses involving stimulation of transmembrane signal transduction pathways. The activation of second messengers supports the hypothesis that a membrane-bound steroid receptor similar to those that mediate peptide hormone biology exists. Skeletal muscle is a target tissue for 1,25(OH)2D3. Avian embryonic skeletal muscle cells (myoblasts/myotubes) have been shown to respond both genomically and non-genomically to the hormone. The present study provides evidence indicating that short-term treatment (1,10 min) with 1,25(OH)2D3 induces translocation of the VDR from the nuclear to the microsomal fraction in chick myoblasts. This translocation is blocked by colchicine, genistein, or herbimycin, suggesting the involvement of microtubular transport and tyrosine kinase/s in the relocation of the receptor. By isolation of plasma membranes, it was demonstrated that the hormone increases the amounts of VDR specifically in this fraction. These results suggest that the nuclear VDR may be the receptor that mediates the non-genomic effects of 1,25(OH)2D3 in chick myoblasts. J. Cell. Biochem. 86: 128,135, 2002. © 2002 Wiley-Liss, Inc. [source] Cadmium-induced hormetic effect in differentiated Caco-2 cells: ERK and p38 activation without cell proliferation stimulationJOURNAL OF CELLULAR PHYSIOLOGY, Issue 1 2010Marc Mantha Cadmium (Cd) is a toxic metal that enters the food chain. Following oral ingestion, the intestinal epithelium may in part protect against Cd toxicity but is also a target tissue. Using human enterocytic-like Caco-2 cells, we have previously shown differences in sensitivity to Cd according to the differentiation status. The present study focuses on Cd effects on differentiated cells. Concentration and time-dependent increases in MTT (3-[4,5-dimethyl-2-thiazol-2-yl]-2,5-diphenyltetrazolium bromide assay) activity were observed in post-confluent cultures exclusively, with a twofold maximal stimulation in 21-day-old cells exposed to 10,µM Cd for 24,h. No concomitant increase in [methyl- 3H] thymidine incorporation was noted and Cd did not modify cell distribution in the cell-cycle phases. However, Cd-induced increase in MTT activity was inhibited by cycloheximine as well as by inhibitors of ERK1/2 and p38, but not by that of JNK. Consistently, Cd increased the levels of ERK1/2 and p38 phosphorylation. Inhibition of Ras-GTP or PI3K enhanced the stimulatory effect of Cd, whereas mTOR inhibition had no effect. Inhibition of G protein-phospholipase and PKC decreased MTT stimulation. These results show a hormesis-like stimulation of Cd on MTT activity in differentiated intestinal cells exclusively. This effect is not related to cell proliferation but more likely to increased protein synthesis which involves ERK1/2 and p38 cascades and possibly PLC-, signaling pathways. Because growth-related differentiation of intestinal cells is linked to the selective and sequential activation of MAPKs, the impacts that these Cd-induced perturbations in signaling pathways may have on intestinal functions clearly deserve to be investigated. J. Cell. Physiol. 224:250,261, 2010 © 2010 Wiley-Liss, Inc. [source] Expression of RIZ1 protein (Retinoblastoma-interacting zinc-finger protein 1) in prostate cancer epithelial cells changes with cancer grade progression and is modulated in vitro by DHT and E2JOURNAL OF CELLULAR PHYSIOLOGY, Issue 3 2009Valentina Rossi The nuclear protein methyl-transferase Retinoblastoma-interacting zinc-finger protein 1 (RIZ1) is considered to be a downstream effector of estrogen action in target tissues. Silencing of RIZ1 expression is common in many tumors. We analyzed RIZ1 expression in normal and malignant prostate tissue and evaluated whether estradiol (E2) or dihydrotestosterone (DHT) treatment modulated RIZ1 in cultured prostate epithelial cells (PEC). Moreover, we studied the possible involvement of RIZ1 in estrogen action on the EPN prostate cell line, constitutively expressing both estrogen receptor (ER)-, and ,. RIZ1 protein, found in the nucleus of normal PECs by immunohistochemistry, was progressively lost in cancer tissues as the Gleason score increased and was only detected in the cytoplasmic compartment. RIZ1 transcript levels, as assayed by semi-quantitative RT-PCR in primary PEC cultures, were significantly reduced in cancer cells (P,<,0.05). In EPN DHT treatment significantly increased RIZ1 transcript and protein levels (P,<,0.05); E2 induced a reduction of S phase without significant changes of RIZ1 expression. In E2-treated EPN cell extracts RIZ co-immunoprecipitated with ER, and ER,. Our data demonstrate that RIZ1 is expressed in normal PECs and down-regulated in cancer cells, with a switch of its sub-cellular localization from the nucleus to the cytoplasm upon cancer grade progression. RIZ1 expression levels in the PECs were modulated by DHT or E2 treatment in vitro. Furthermore, the E2 effects on ER-expressing prostate cells involve RIZ1, which confirms a possible role for ER-mediated pathways in a non-classic E2 -target tissue. J. Cell. Physiol. 221: 771,777, 2009. © 2009 Wiley-Liss, Inc. [source] Autoantigens in systemic autoimmunity: critical partner in pathogenesisJOURNAL OF INTERNAL MEDICINE, Issue 6 2009A. Rosen Abstract. Understanding the mechanisms of human autoimmune rheumatic diseases presents a major challenge, due to marked complexity involving multiple domains, including genetics, environment and kinetics. In spite of this, the immune response in each of these diseases is largely specific, with distinct autoantibodies associated with different disease phenotypes. Defining the basis of such specificity will provide important insights into disease mechanism. Accumulating data suggest an interesting paradigm for antigen selection in autoimmunity, in which target tissue and immune effector pathways form a mutually reinforcing partnership. In this model, distinct autoantibody patterns in autoimmunity may be viewed as the integrated, amplified output of several interacting systems, including: (i) the specific target tissue, (ii) the immune effector pathways that modify antigen structure and cause tissue damage and dysfunction, and (iii) the homeostatic pathways activated in response to damage (e.g. regeneration/differentiation/cytokine effects). As unique antigen expression and structure may occur exclusively under these amplifying circumstances, it is useful to view the molecules targeted as ,neo-antigens', that is, antigens expressed under specific conditions, rather than ubiquitously. This model adds an important new dynamic element to selection of antigen targets in autoimmunity, and suggests that the amplifying loop will only be identified by studying the diseased target tissue in vivo. [source] An update on Behçet's diseaseJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 1 2007A Kalayciyan Abstract Behçet's disease (Adamantiades-Behçet's disease, ABD) is a multisystemic inflammatory disease, the pathogenesis of which is still a mystery. Many questions are still to be answered and the available diverse data need to be brought together to be compared and analysed. There is at least consensus on the effect of possible, but currently unknown, environmental triggering factor(s) against a background of genetic susceptibility. The possible aetiological factors form a broad spectrum, with infectious agents being the most probable ones. Whatever the stimulus is, the target tissue seems to be the small blood vessels, with various consequences of either vasculitis and/or thrombosis in many organ systems. The endothelium seems to be the primary target in this disease; however, it may just be the subject of the bizarre behaviour of the immune system. The diverse existing data could be interpreted in favour of either explanation. A similar confusion exists about the thrombotic tendency in Adamantiades-Behçet's disease, in terms of whether a primary hypercoagulability is present or whether it is secondary to inflammation. Recent interesting immunological data promise a way out of the existing dilemma. These findings will be outlined within the context of possible hypotheses and attention will be paid to further investigations that are needed. [source] Effects of age and GDNF on noradrenergic innervation of the hippocampal formation: Studies from intraocular graftsMICROSCOPY RESEARCH AND TECHNIQUE, Issue 5 2001A.-C. Granholm Abstract Recent studies have suggested that factors in the target tissue influence the degree of plasticity and regeneration following aging and/or specific insults. We have investigated whether young or aged targets differ in their noradrenergic innervation from fetal locus coeruleus (LC) neurons, and also if a specific growth factor, glial cell line-derived neurotrophic factor (GDNF) can affect this innervation pattern. Tissue pieces of fetal brainstem and young (3 months) or old (18 months) iris tissue were transplanted simultaneously into the anterior chamber of the eye of adult hosts. We found that aged iris transplants became innervated to a significantly lesser degree by the cografted LC neurons than young iris transplants. Fetal hippocampal tissue was then grafted to adult hosts, and a fetal brainstem graft containing LC neurons was placed adjacent to the first graft, either at 3 or 21 months post-grafting. Thus, old/young chimeras of the noradrenergic coeruleo-hippocampal pathway were created. Aged hippocampal grafts received a much less dense innervation from co-grafted LC neurons than young hippocampal grafts. Tyrosine hydroxylase-positive-immunoreactive innervation was only found in the outskirts of aged grafts, while the young hippocampal grafts contained an even innervation pattern. The innervation density of hippocampal grafts was significantly enhanced by GDNF treatment. These findings demonstrate that target-derived factors may regulate neuronal plasticity, and that the age of the target is more important for innervation properties than the age of the neuron innervating a particular target. Microsc. Res. Tech. 54:298,308, 2001. © 2001 Wiley-Liss, Inc. [source] Biodegradable polymers applied in tissue engineering research: a reviewPOLYMER INTERNATIONAL, Issue 2 2007Monique Martina Abstract Typical applications and research areas of polymeric biomaterials include tissue replacement, tissue augmentation, tissue support, and drug delivery. In many cases the body needs only the temporary presence of a device/biomaterial, in which instance biodegradable and certain partially biodegradable polymeric materials are better alternatives than biostable ones. Recent treatment concepts based on scaffold-based tissue engineering principles differ from standard tissue replacement and drug therapies as the engineered tissue aims not only to repair but also regenerate the target tissue. Cells have been cultured outside the body for many years; however, it has only recently become possible for scientists and engineers to grow complex three-dimensional tissue grafts to meet clinical needs. New generations of scaffolds based on synthetic and natural polymers are being developed and evaluated at a rapid pace, aimed at mimicking the structural characteristics of natural extracellular matrix. This review focuses on scaffolds made of more recently developed synthetic polymers for tissue engineering applications. Currently, the design and fabrication of biodegradable synthetic scaffolds is driven by four material categories: (i) common clinically established polymers, including polyglycolide, polylactides, polycaprolactone; (ii) novel di- and tri-block polymers; (iii) newly synthesized or studied polymeric biomaterials, such as polyorthoester, polyanhydrides, polyhydroxyalkanoate, polypyrroles, poly(ether ester amide)s, elastic shape-memory polymers; and (iv) biomimetic materials, supramolecular polymers formed by self-assembly, and matrices presenting distinctive or a variety of biochemical cues. This paper aims to review the latest developments from a scaffold material perspective, mainly pertaining to categories (ii) and (iii) listed above. Copyright © 2006 Society of Chemical Industry [source] VP22-mediated intercellular transport correlates with enhanced biological activity of MybEngrailed but not (HSV-I) thymidine kinase fusion proteins in primary vascular cells following non-viral transfectionTHE JOURNAL OF GENE MEDICINE, Issue 3 2005Paul J. Sheridan Background The intercellular transport properties of the herpes simplex virus (HSV) protein VP22 have been harnessed to enhance the effectiveness of viral gene transfer. We investigated the intercellular transport and biological effects of VP22 fused with the dominant negative c-Myb chimera, MybEngrailed (MybEn) and HSV-I thymidine kinase (TK), in primary vascular smooth muscle cells (VSMC) following non-viral transfection. Materials and methods Porcine VSMC transfected with plasmids encoding MybEn, TK and their respective N- and C-terminal VP22 fusion proteins were assayed for the extent and distribution of transgene expression (by immunohistochemistry), culture growth and apoptosis. Results The N-terminal MybEn fusion with VP22 (MybEnVP22) and both TK fusions, but not VP22MybEn, exhibited intercellular spread from primary transfected to up to 200 surrounding cells. pMybEnVP22 -transfected cultures exhibited growth inhibition and apoptosis rates that were 10.6 ± 3.6 and 3.2 ± 1.0 fold higher than in pMybEn -transfected cultures; pVP22MybEn -transfected cultures showed no difference in these parameters. pTK -transfected cultures underwent 60,70% cell death in the presence of ganciclovir despite <2% primary transfection, which was not increased in cultures transfected with plasmids encoding VP22-TK fusions. Conclusions The close correlation between immunocytochemical and biological assays suggests that intercellular transport is crucial to the enhanced biological activity of the MybEnVP22 fusion. The ,intrinsic' bystander activity of TK was 4-fold greater than was ,engineered' by VP22 fusion, probably reflecting the abundance of gap junctions between VSMC. VP22 fusion may enhance the efficiency of non-viral gene delivery when combined with the appropriate therapeutic transgene, target tissue and transfection method. Copyright © 2004 John Wiley & Sons, Ltd. [source] Gene therapy for HIV/AIDS: the potential for a new therapeutic regimenTHE JOURNAL OF GENE MEDICINE, Issue 8 2003Greg Fanning Abstract Human Immunodeficiency Virus (HIV) is the etiologic agent of Acquired Immunodeficiency Syndrome (AIDS). HIV/AIDS is a disease that, compared with the not so distant past, is now better held in check by current antiretroviral drugs. However, it remains a disease not solved. Highly active antiretroviral therapy (HAART) generally uses two non-nucleoside and one nucleoside reverse transcriptase (RT) inhibitor or two non-nucleoside RT and one protease inhibitor. HAART is far more effective than the mono- or duo-therapy of the past, which used compounds like the nucleoside reverse transcriptase inhibitor AZT or two nucleoside reverse transcriptase inhibitors. However, even with the relatively potent drug cocktails that comprise HAART, there are the issues of (i) HIV escape mutants, (ii) an apparent need to take the drugs in an ongoing manner, and (iii) the drugs' side effects that are often severe. This review speaks to the potential addition to these potent regimens of another regimen, namely the genetic modification of target hematopoietic cells. Such a new treatment paradigm is conceptually attractive as it may yield the constant intracellular expression of an anti-HIV gene that acts to inhibit HIV replication and pathogenicity. A body of preclinical work exists showing the inhibition of HIV replication and decreased HIV pathogenicity by anti-HIV genetic agents. This preclinical work used hematopoietic cell lines and primary cells as the target tissue. More recently, several clinical trials have sought to test this concept in vivo. Copyright © 2003 John Wiley & Sons, Ltd. [source] Imaging-guided convection-enhanced delivery and gene therapy of glioblastomaANNALS OF NEUROLOGY, Issue 4 2003Juergen Voges MD In a prospective phase I/II clinical study, we treated eight patients suffering from recurrent glioblastoma multiform with stereotactically guided intratumoral convection-enhanced delivery of an HSV-1- tk gene,bearing liposomal vector and systemic ganciclovir. Noninvasive identification of target tissue together with assessment of vector-distribution volume and the effects of gene therapy were achieved using magnetic resonance imaging and positron emission tomography. The treatment was tolerated well without major side effects. In two of eight patients, we observed a greater than 50% reduction of tumor volume and in six of eight patients focal treatment effects. Intracerebral infusion of contrast medium before vector application displayed substantial inhomogeneity of tissue staining indicating the need of test infusions to monitor the mechanical distribution of vectors. Visualization of therapeutic effects on tumor metabolism and documentation of gene expression using positron emission tomography indicated that molecular imaging technology appears to be essential for the further development of biological treatment strategies. [source] Electromagnetic Field Treatment of Nerve Crush Injury in a Rat Model: Effect of Signal Configuration on Functional RecoveryBIOELECTROMAGNETICS, Issue 4 2007Janet L. Walker Abstract Electromagnetic fields (EMFs) have been demonstrated to enhance mammalian peripheral nerve regeneration in vitro and in vivo. Using an EMF signal shown to enhance neurite outgrowth in vitro, we tested this field in vivo using three different amplitudes. The rat sciatic nerve was crushed. Whole body exposure was performed for 4 h/day for 5 days in a 96-turn solenoid coil controlled by a signal generator and power amplifier. The induced electric field at the target tissue consisted of a bipolar rectangular pulse, having 1 and 0.3 ms durations in each polarity, respectively. Pulse repetition rate was 2 per second. By varying the current, the coils produced fields consisting of sham (no current) and peak magnetic fields of 0.03 mT, 0.3 mT, and 3 mT, corresponding to peak induced electric fields of 1, 10, and 100 µV/cm, respectively, at the tissue target. Walking function was assessed over 43 days using video recording and measurement of the 1,5 toe-spread, using an imaging program. Comparing injured to uninjured hind limbs, mean responses were evaluated using a linear mixed statistical model. There was no difference found in recovery of the toe-spread function between any EMF treatments compared to sham. Bioelectromagnetics 28:256,263, 2007. © 2007 Wiley-Liss, Inc. [source] Equally potent inhibitors of cholesterol synthesis in human hepatocytes have distinguishable effects on different cytochrome P450 enzymesBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 9 2000L.H. Cohen Abstract Six 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (the present cholesterol-lowering drugs known as statins), lovastatin (L), simvastatin (S), pravastatin (P), fluvastatin (F), atorvastatin (A) and cerivastatin (C) are shown to be potent inhibitors of cholesterol synthesis in human hepatocytes, the target tissue for these drugs in man. All six inhibited in the nM range (IC50 values: 0.2,8.0 nM). As daily used cholesterol-lowering drugs they are likely coadministered with other drugs. While several cytochrome P450 (CYP) enzymes are involved in drug metabolism in the liver and thus play an important role in drug,drug interaction it was investigated which of these enzymes are influenced by the active forms of the six statins. These enzyme activities were studied in human liver microsomal preparations, and in simian and human hepatocytes in primary culture. The following CYP reactions were used: nifedipine aromatization (CYP3A4), testosterone 6,-hydroxylation (CYP3A4), tolbutamide methylhydroxylation (CYP2C9), S -mephenytoin 4-hydroxylation (CYP2C19), bufuralol 1,-hydroxylation (CYP2D6), aniline 4-hydroxylation (CYP2E1), coumarin 7-hydroxylation (CYP2A6) and 7-ethoxyresorufin O -dealkylation (CYP1A1/2). In the human liver microsomes the statins (concentrations up to 400 µM) did not influence the CYP1A1/2 activity and hardly the CYP2A6 and CYP2E1 activities. Except P, the other five statins were stronger inhibitors of the CYP2C19 activity with IC50 values around 200 µM and the same holds for the effect of A, C and F on the CYP2D6 activity. L and S were weaker inhibitors of the latter enzyme activity, whereas P did not influence both activities. About the same was observed for the statin effect on CYP2C9 activity, except that F was a strong inhibitor of this activity (IC50 value: 4 µM). Using the assay of testosterone 6,-hydroxylation the CYP3A4 activity was decreased by L, S and F with IC50 values of about 200 µM and a little more by C and A (IC50 around 100 µM). P had hardly an effect on this activity. To a somewhat less extent the same trend was seen when CYP3A4 activity was measured using nifedipine as substrate. The inhibitory effects observed in microsomes were verified in suspension culture of freshly isolated hepatocytes from Cynomolgus monkey (as a readily available model) and of human hepatocytes. In general the same trends were seen as in the human microsomes, except that in some cases the inhibition of the CYP activity was less, possibly by the induction of the particular CYP enzyme by incubation of the cells with a particular statin. F remained a strong inhibitor of CYP2C9 activity in human and monkey hepatocytes. A induced the CYP2C9 in monkey hepatocytes but was an inhibitor of the CYP2C9 in human hepatocytes. A, S, L and C were moderate inhibitors in both cellular systems of CYP3A4. P was not affecting any of the CYP activities in the three systems studied. It is concluded that different CYP enzymes interact with different statins and therefore differences in between these drugs are to be expected when drug,drug interaction is considered. Copyright © 2000 John Wiley & Sons, Ltd. [source] Plasma facilitated delivery of DNA to skinBIOTECHNOLOGY & BIOENGINEERING, Issue 5 2009Richard J. Connolly Abstract Non-viral delivery of cell-impermeant drugs and DNA in vivo has traditionally relied upon either chemical or physical stress applied directly to target tissues. Physical methods typically use contact between an applicator, or electrode, and the target tissue and may involve patient discomfort. To overcome contact-dependent limitations of such delivery methodologies, an atmospheric helium plasma source was developed to deposit plasma products onto localized treatment sites. Experiments performed in murine skin showed that samples injected with plasmid DNA encoding luciferase and treated with plasma demonstrated increased levels of expression relative to skin samples that received injections of DNA alone. Increased response relative to injection alone was observed when either positive or negative voltage was used to generate the helium plasma. Quantitative results over a 26-day follow-up period showed that luciferase levels as high as 19-fold greater than the levels obtained by DNA injection alone could be achieved. These findings indicate that plasmas may compete with other physical delivery methodologies when skin is the target tissue. Biotechnol. Bioeng. 2009; 104: 1034,1040. © 2009 Wiley Periodicals, Inc. [source] Carbon monoxide-induced axial skeletal dysmorphogenesis in the chick embryo,,BIRTH DEFECTS RESEARCH, Issue 4 2003Peter G. Alexander Abstract BACKGROUND Congenital axial skeletal defects affect two to three individuals per 1,000 live births. Without strong evidence for heritability, the cause is assumed to be multi-factorial. Carbon monoxide (CO), an increasingly prevalent environmental toxicant, is a potential environmental component in the etiology of these defects. The chick embryo is a useful model for the characterization and assessment of the mechanism(s) of action of basic developmental mechanisms. METHODS We have determined a critical period and dose for CO teratogenicity and established a model of CO-induced axial skeletal dysmorphogenesis in the chick embryo. The resulting phenotypes reveal a spectrum of axial skeletal defects ranging from minor defects of the vertebral canal and inter,vertebral discs, to thoraco,lumbar scoliosis, to a tailless phenotype reminiscent of caudal dysgenesis syndrome. These axial skeletal defects have been related to earlier developmental defects in somitogenesis, including errors in segmentation and epithelialization and the expression of the somitic epithelialization factor, Paraxis. We have examined patterns of cell death and apoptosis in CO exposed chick embryos to assess the target tissue(s) involved in the teratogenicity of CO. RESULTS With respect to the embryonic axis, the neural tube was found to be the most sensitive to CO-induced apoptosis, followed by the somitic mesoderm and Hensen's node. CONCLUSIONS We hypothesize that the somitic defects and the resulting axial skeletal dysmorphogenesis are caused by disrupted neural tube or ectoderm functions related to somite formation and maintenance. We also hypothesize that CO-induced dysmorphogenesis at this critical period of somitogenesis is caused by the overabundance of CO acting endogenously as a cellular signal, while coincidentally exerting its influence as a toxicant of oxygen delivery or utilization. Birth Defects Research (Part A) 67:219,230, 2003. Published 2003 Wiley-Liss, Inc. [source] Nitric oxide and inflammationACTA OPHTHALMOLOGICA, Issue 2009AD DICK Purpose The talk will discuss the dichomatous role of nitric oxide in inflammation as a result of macrophage activation and also its role in controlling T cell responses. Methods We have used both microglial cell cultures, bone marrow derived macrophages and finally animal models of uveitis to dissect the role of macrophage activation and nitric oxide production in both tissue damage and limiting the extent of the inflammatory response. Results Macrophages when activated via T cell responses secreting interferon gamma, elicit a TNF-dependent nitrite response. Inhibiting nitric oxide activity by either suppressing NOS2 or via inhibiting TNF activity results in marked suppression of macrophage activation and reduction in retinal damage observed during experimental autoimmune uveoretinitis (EAU). Macrophages regulate T cell responses, in part via nitric oxide production, but is dependent upon IFN-gamma and autocrine TNF signalling via TNFReceptor1. Conclusion TNF and Interferon play essential roles in generating macrophage activation that elaborates in turn nitric oxide production. The nitric oxide, whilst damaging to cell membranes thus contributing to tissue damage during autoimmunity, also assists in regulating T cell responses by down regulating of T cell proliferation within the target tissue. [source] Developmental changes in neurite outgrowth responses of dorsal root and sympathetic ganglia to GDNF, neurturin, and arteminDEVELOPMENTAL DYNAMICS, Issue 3 2003H. Yan Abstract The ability of glial cell line,derived neurotrophic factor (GDNF), neurturin, and artemin to induce neurite outgrowth from dorsal root, superior cervical, and lumbar sympathetic ganglia from mice at a variety of development stages between embryonic day (E) 11.5 and postnatal day (P) 7 was examined by explanting ganglia onto collagen gels and growing them in the presence of agarose beads impregnated with the different GDNF family ligands. Artemin, GDNF, and neurturin were all capable of influencing neurite outgrowth from dorsal root and sympathetic ganglia, but the responses of each neuron type to the different ligands varied during development. Neurites from dorsal root ganglia responded to artemin at P0 and P7, to GDNF at E15.5 and P0, and to neurturin at E15.5, P0, and P6/7; thus, artemin, GDNF, and neurturin are all capable of influencing neurite outgrowth from dorsal root ganglion neurons. Neurites from superior cervical sympathetic ganglia responded significantly to artemin at E15.5, to GDNF at E15.5 and P0, and to neurturin at E15.5. Neurites from lumbar sympathetic ganglia responded to artemin at all stages from E11.5 to P7, to GDNF at P0 and P7 and to neurturin at E11.5 to P6/7. Combined with the data from previous studies that have examined the expression of GDNF family members, our data suggest that artemin plays a role in inducing neurite outgrowth from young sympathetic neurons in the early stages of sympathetic axon pathfinding, whereas GDNF and neurturin are likely to be important at later stages of sympathetic neuron development in inducing axons to enter particular target tissues once they are in the vicinity or to induce branching within target tissues. Superior cervical and lumbar sympathetic ganglia showed temporal differences in their responsiveness to artemin, GDNF, and neurturin, which probably partly reflects the rostrocaudal development of sympathetic ganglia and the tissues they innervate. Developmental Dynamics 227:395,401, 2003. © 2003 Wiley-Liss, Inc. [source] | ||||||||||||||||||||||||||||||||||||||||