5,670 research outputs found
Circulating endothelial cell-derived extracellular vesicles mediate the acute phase response and sickness behaviour associated with CNS inflammation.
Brain injury elicits a systemic acute-phase response (APR), which is responsible for co-ordinating the peripheral immunological response to injury. To date, the mechanisms responsible for signalling the presence of injury or disease to selectively activate responses in distant organs were unclear. Circulating endogenous extracellular vesicles (EVs) are increased after brain injury and have the potential to carry targeted injury signals around the body. Here, we examined the potential of EVs, isolated from rats after focal inflammatory brain lesions using IL-1β, to activate a systemic APR in recipient naïve rats, as well as the behavioural consequences of EV transfer. Focal brain lesions increased EV release, and, following isolation and transfer, the EVs were sequestered by the liver where they initiated an APR. Transfer of blood-borne EVs from brain-injured animals was also enough to suppress exploratory behaviours in recipient naïve animals. EVs derived from brain endothelial cell cultures treated with IL-1β also activated an APR and altered behaviour in recipient animals. These experiments reveal that inflammation-induced circulating EVs derived from endothelial cells are able to initiate the APR to brain injury and are sufficient to generate the associated sickness behaviours, and are the first demonstration that EVs are capable of modifying behavioural responses
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Involvement of Bruton's tyrosine kinase in FcepsilonRI-dependent mast cell degranulation and cytokine production.
We investigated the role of Bruton's tyrosine kinase (Btk) in FcepsilonRI-dependent activation of mouse mast cells, using xid and btk null mutant mice. Unlike B cell development, mast cell development is apparently normal in these btk mutant mice. However, mast cells derived from these mice exhibited significant abnormalities in FcepsilonRI-dependent function. xid mice primed with anti-dinitrophenyl monoclonal IgE antibody exhibited mildly diminished early-phase and severely blunted late-phase anaphylactic reactions in response to antigen challenge in vivo. Consistent with this finding, cultured mast cells derived from the bone marrow cells of xid or btk null mice exhibited mild impairments in degranulation, and more profound defects in the production of several cytokines, upon FcepsilonRI cross-linking. Moreover, the transcriptional activities of these cytokine genes were severely reduced in FcepsilonRI-stimulated btk mutant mast cells. The specificity of these effects of btk mutations was confirmed by the improvement in the ability of btk mutant mast cells to degranulate and to secrete cytokines after the retroviral transfer of wild-type btk cDNA, but not of vector or kinase-dead btk cDNA. Retroviral transfer of Emt (= Itk/Tsk), Btk's closest relative, also partially improved the ability of btk mutant mast cells to secrete mediators. Taken together, these results demonstrate an important role for Btk in the full expression of FcepsilonRI signal transduction in mast cells
Rare and Frequent Promoter Methylation, Respectively, of TSHZ2 and 3 Genes That Are Both Downregulated in Expression in Breast and Prostate Cancers
Neoplastic cells harbor both hypomethylated and hypermethylated regions of DNA. Whereas hypomethylation is found mainly in repeat sequences, regional hypermethylation has been linked to the transcriptional silencing of certain tumor suppressor genes. We attempted to search for candidate genes involved in breast/prostate carcinogenesis, using the criteria that they should be expressed in primary cultures of normal breast/prostate epithelial cells but are frequently downregulated in breast/prostate cancer cell lines and that their promoters are hypermethylated.We identified several dozens of candidates among 194 homeobox and related genes using Systematic Multiplex RT-PCR and among 23,000 known genes and 23,000 other expressed sequences in the human genome by DNA microarray hybridization. An additional examination, by real-time qRT-PCR of clinical specimens of breast cancer, further narrowed the list of the candidates. Among them, the most frequently downregulated genes in tumors were NP_775756 and ZNF537, from the homeobox gene search and the genome-wide search, respectively. To our surprise, we later discovered that these genes belong to the same gene family, the 3-member Teashirt family, bearing the new names of TSHZ2 and TSHZ3. We subsequently determined the methylation status of their gene promoters. The TSHZ3 gene promoter was found to be methylated in all the breast/prostate cancer cell lines and some of the breast cancer clinical specimens analyzed. The TSHZ2 gene promoter, on the other hand, was unmethylated except for the MDA-MB-231 breast cancer cell line. The TSHZ1 gene was always expressed, and its promoter was unmethylated in all cases.TSHZ2 and TSHZ3 genes turned out to be the most interesting candidates for novel tumor suppressor genes. Expression of both genes is downregulated. However, differential promoter methylation suggests the existence of distinctive mechanisms of transcriptional inactivation for these genes
A systematic review of biomarkers for disease progression in Parkinson's disease
Peer reviewedPublisher PD
Recurrent advanced colonic cancer occurring 11 years after initial endoscopic piecemeal resection: a case report
<p>Abstract</p> <p>Background</p> <p>The high frequency of local recurrence occurring after endoscopic piecemeal resection (EPMR) for large colorectal tumors is a serious problem. However, almost all of these cases of local recurrence can be detected within 1 year and cured by additional endoscopic resection. We report a rare case of recurrent advanced colonic cancer diagnosed 11 years after initial EPMR treatment.</p> <p>Case presentation</p> <p>A 65-year-old male was diagnosed with a sigmoid colon lesion following a routine health check-up. Total colonoscopy revealed a 12 mm type 0-Is lesion in the sigmoid colon, which was diagnosed as an adenoma or intramucosal cancer and treated by EPMR in 1996. The post-resection defect was closed completely using metallic endoclips to avoid delayed bleeding. In 2007, at the third follow up, colonoscopy revealed a 20 mm submucosal tumor (SMT) like recurrence at the site of the previous EPMR. The recurrent lesion was treated by laparoscopic assisted sigmoidectomy with lymph node dissection.</p> <p>Conclusion</p> <p>When it is difficult to evaluate the depth and margins of resected tumors following EPMR, it is important that the defect is not closed in order to avoid tumor implantation, missing residual lesions and to enable earlier detection of recurrence. It is crucial that the optimal follow-up protocol for EPMR cases is clarified, particularly how often and for how long they should be followed.</p
Strain-dependent host transcriptional responses to toxoplasma infection are largely conserved in mammalian and avian hosts
Toxoplasma gondii has a remarkable ability to infect an enormous variety of mammalian and avian species. Given this, it is surprising that three strains (Types I/II/III) account for the majority of isolates from Europe/North America. The selective pressures that have driven the emergence of these particular strains, however, remain enigmatic. We hypothesized that strain selection might be partially driven by adaptation of strains for mammalian versus avian hosts. To test this, we examine in vitro, strain-dependent host responses in fibroblasts of a representative avian host, the chicken (Gallus gallus). Using gene expression profiling of infected chicken embryonic fibroblasts and pathway analysis to assess host response, we show here that chicken cells respond with distinct transcriptional profiles upon infection with Type II versus III strains that are reminiscent of profiles observed in mammalian cells. To identify the parasite drivers of these differences, chicken fibroblasts were infected with individual F1 progeny of a Type II x III cross and host gene expression was assessed for each by microarray. QTL mapping of transcriptional differences suggested, and deletion strains confirmed, that, as in mammalian cells, the polymorphic rhoptry kinase ROP16 is the major driver of strain-specific responses. We originally hypothesized that comparing avian versus mammalian host response might reveal an inversion in parasite strain-dependent phenotypes; specifically, for polymorphic effectors like ROP16, we hypothesized that the allele with most activity in mammalian cells might be less active in avian cells. Instead, we found that activity of ROP16 alleles appears to be conserved across host species; moreover, additional parasite loci that were previously mapped for strain-specific effects on mammalian response showed similar strain-specific effects in chicken cells. These results indicate that if different hosts select for different parasite genotypes, the selection operates downstream of the signaling occurring during the beginning of the host's immune response. © 2011 Ong et al
Calcaneal osteomyelitis presenting with acute tarsal tunnel syndrome: a case report
<p>Abstract</p> <p>Introduction</p> <p>Cases of acute tarsal tunnel syndrome are rare. To the best of our knowledge, we describe the only reported case of acute posterior tibial nerve compression resulting from adjacent haemotogenous pyogenic calcaneal osteomyelitis.</p> <p>Case presentation</p> <p>A previously healthy 38-year-old Caucasian woman developed symptoms of acute tarsal tunnel syndrome in her right foot over a six-day period. No antecedent trauma or systemic symptoms were noted. Magnetic resonance imaging and bone scan imaging, followed by surgical decompression and bone biopsy confirmed a diagnosis of <it>Staphylococcus aureus </it>calcaneal osteomyelitis. Her pain and paraesthesia disappeared after the operation, while her inflammatory markers normalised during a 12-week course of antibiotics. After four years she has remained asymptomatic without any indication of recurrence.</p> <p>Conclusion</p> <p>This case is not just unique in describing osteomyelitis as a cause of tarsal tunnel syndrome, because haemotogenous calcaneal osteomyelitis is in itself a rare pathology. We recommend considering infection as a differential diagnosis in patients presenting with acute tarsal tunnel syndrome.</p
Maximal Spontaneous Photon Emission and Energy Loss from Free Electrons
Free electron radiation such as Cerenkov, Smith--Purcell, and transition
radiation can be greatly affected by structured optical environments, as has
been demonstrated in a variety of polaritonic, photonic-crystal, and
metamaterial systems. However, the amount of radiation that can ultimately be
extracted from free electrons near an arbitrary material structure has remained
elusive. Here we derive a fundamental upper limit to the spontaneous photon
emission and energy loss of free electrons, regardless of geometry, which
illuminates the effects of material properties and electron velocities. We
obtain experimental evidence for our theory with quantitative measurements of
Smith--Purcell radiation. Our framework allows us to make two predictions. One
is a new regime of radiation operation---at subwavelength separations, slower
(nonrelativistic) electrons can achieve stronger radiation than fast
(relativistic) electrons. The second is a divergence of the emission
probability in the limit of lossless materials. We further reveal that such
divergences can be approached by coupling free electrons to photonic bound
states in the continuum (BICs). Our findings suggest that compact and efficient
free-electron radiation sources from microwaves to the soft X-ray regime may be
achievable without requiring ultrahigh accelerating voltages.Comment: 7 pages, 4 figure
The creation of new rotation arc to the rat latissimus dorsi musculo-cutaneous flap with delay procedures
BACKGROUND: Latissimus dorsi musculocutaneous flap is one of the most frequently performed reconstructive techniques in surgery. Latissimus dorsi muscle has two arcs of rotation. It is classified as type V muscle. This muscle can be elevated on the thoracodorsal artery to cover large defects in the anterior chest and also, the muscle can be elevated on the segmental vessels to cover midline defects posteriorly. The aim of this study was to create a new arc of rotation on a vertical axis for the muscle and investigate effectiveness of vascular and chemical delays on the latissimus dorsi muscle flap with an inferior pedicle in an experimental rat model. We hypothesized that the latissimus dorsi muscle would be based on inferior pedicle by delay procedures. METHODS: We tested two different types of delay: vascular and combination of vascular and chemical. We also tried to determine how many days of "delay" can elicit beneficial effects of vascular and combination delays in an inferior pedicled latissimus dorsi musculocutaneous flap. To accomplish this, 48 male Sprague-Dawley rats were randomly subjected to vascular or combination delay (vascular and chemical). In addition, one ear of each rat was assigned into a delay procedure and the other ear was used as a control. Results were evaluated macroscopically, and micro-angiography and histological examinations were also performed. As a result, there was a significant difference in viable flap areas between vascular delay alone and control groups (p < 0.05). RESULTS: The higher rate of flap viability was obtained in seven-day vascular delay alone. However, there was no significant difference in the viability between seven-day vascular delay and five-day vascular delay (p < 0.05), so the earliest time when the flap viability could be obtained was at five days. The rate of flap viability was significantly higher in the vascular delay combined with chemical delay than the control group (p < 0.05). CONCLUSION: The combination of vascular and chemical delays increased the rate of viability. Nevertheless, there was no significant difference between vascular delay alone and combination of vascular and chemical delays. Chemical delay did not significantly decrease the delay period. Better histological and microangiographical results were achieved in delay groups compared to control groups. We concluded that the arch of the latissimus dorsi musculocutaneous flap can be changed and the flap can be used for various purposes with the delay procedures
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