Galectin-1 plays an essential role in intravenous tolerance in experimental autoimmune encephalomyelitis (BA4P.139)

Multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis (EAE), are inflammatory demyelinating diseases of the central nervous system (CNS). EAE can be induced by immunizing mice with myelin oligodendrocyte glycoprotein-derived peptide, MOG35-55, in adjuvant. It has been previously demonstrated that intravenous (i.v.) injection of MOG35-55 post immunization induction suppresses disease development, a phenomenon called i.v. tolerance. The glycan-binding protein galectin-1, produced primarily by regulatory T cells plays an immunoregulatory role in EAE by inducing tolerogenic DCs and IL-10-producing regulatory type 1 T cells (Tr1). To examine the role of galectin-1 in i.v. tolerance, we administered MOG35-55 peptide i.v. to wild-type (WT) and galectin-1-/- (Gal1-/-) mice with ongoing EAE. MOG35-55 rapidly suppressed disease in the WT, but not in the Gal1-/- mice. Expression of pro-inflammatory cytokines IFN-gamma and IL-17A were reduced in the CNS and periphery of tolerized WT mice, while the number of Tr1 cells increased in the periphery. In contrast, i.v. MOG35-55 significantly increased IFN-gamma and IL-17A in the CNS and periphery of Gal1-/-mice and these mice had markedly fewer Tr1 cells in the periphery. Our data suggest that galectin-1 mediated i.v. tolerance induction is dependent on the downregulation of Th1 and Th17 pro-inflammatory responses, and enhanced development of Tr1 cells.

Prevalence of intestinal parasite infections and associated clinical symptoms among patients with end-stage renal disease undergoing hemodialysis

PURPOSE

Intestinal parasitic infections (IPIs) can result in high morbidity and mortality, particularly in immunocompromised patients. Infectious diseases are among the main causes of death in end-stage renal disease (ESRD) patients due to their impaired immune systems. The aim of this study was to determine the prevalence IPIs and their associated symptoms in ESRD patients.

METHODS

In this case-control study, the fecal samples of 78 ESRD patients undergoing hemodialysis and 140 controls without any kidney problems were analyzed for intestinal parasites using direct-smear, formol-ether and modified Ziehl-Neelsen staining techniques.

RESULTS

The difference in the prevalence of IPIs between ESRD patients (30.7 %) and the control group (10.7 %) was significant (OR = 3.7; 95 % CI = 1.8-7.61; P < 0.001). Blastocystis (14.1 %) and Cryptosporidium spp.(11.5 %) were the most common IPIs detected in ESRD patients, and the presence of Cryptosporidium spp. was significantly associated with diarrhea in ESRD patients (OR = 16; 95 % CI = 1.54-166.05; P < 0.05). Leukocytosis, diarrhea, weight loss, nausea/vomiting and bloating were also significantly higher in the hemodialysis group when compared with the control group.

CONCLUSION

The current study revealed a high prevalence of intestinal parasites and related clinical symptoms in ESRD patients undergoing hemodialysis. Since hemodialysis patients are immunocompromised and intestinal parasites can cause serious clinical complications, we suggest that stool examination for intestinal parasites, with an emphasis on detection of Cryptosporidium spp. and Blastocystis, should be incorporated into the routine clinical care for these patients. Measures for preventing the acquisition of IPIs are also recommended.

Immunotherapy using lipopolysaccharide-stimulated bone marrow-derived dendritic cells to treat experimental autoimmune encephalomyelitis

Lipopolysaccharide (LPS) produced by Gram-negative bacteria induces tolerance and suppresses inflammatory responses in vivo; however, the mechanisms are poorly understood. In this study we show that LPS induces apoptosis of bone marrow-derived dendritic cells (DCs) and modulates phenotypes of DCs. LPS treatment up-regulates expression of tolerance-associated molecules such as CD205 and galectin-1, but down-regulates expression of Gr-1 and B220 on CD11c(+) DCs. Moreover, LPS treatment regulates the numbers of CD11c(+) CD8(+) , CD11c(+) CD11b(low) and CD11c(+) CD11b(hi) DCs, which perform different immune functions in vivo. Our data also demonstrated that intravenous transfer of LPS-treated DCs blocks experimental autoimmune encephalomyelitis (EAE) development and down-regulates expression of retinoic acid-related orphan receptor gamma t (ROR-γt), interleukin (IL)-17A, IL-17F, IL-21, IL-22 and interferon (IFN)-γ in myelin oligodendrocyte glycoprotein (MOG)-primed CD4(+) T cells in the peripheral environment. These results suggest that LPS-induced apoptotic DCs may lead to generation of tolerogenic DCs and suppress the activity of MOG-stimulated effector CD4(+) T cells, thus inhibiting the development of EAE in vivo. Our results imply a potential mechanism of LPS-induced tolerance mediated by DCs and the possible use of LPS-induced apoptotic DCs to treat autoimmune diseases such as multiple sclerosis.

Investigation of MMP-2 and MMP-9 activities in canine sera with dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is accompanied by myocytes and connective tissue changes. Matrix metalloproteinases (MMPs) play important roles in cardiac remodeling. It seems that the gelatinases (MMP-2 and MMP-9) are effective enzymes in cardiomyopathy. Dilated cardiomyopathy was confirmed in 22 dogs (patient group) including 11 female and 11 male by clinical examination, auscultation, thoracic radiography and echocardiography. 17 healthy dogs (control group) with similar weight and breed to patients were also selected from referred cases to Small Animal Hospital of the Veterinary Faculty of Tehran University and the same diagnostic procedures were performed on them. After that, serum MMP-2 and MMP-9 of control and patient groups were measured by semi-quantitative zymography. Semiquantitative analysis of zymograms from canine serums with DCM showed that total MMP-9 in patients is more than control group, while there was no significant difference in total MMP-2 between the two groups. Pro-MMP-2 was not detected in patient group but its active form was present in both groups, of course MMP-2 activity in patients was significantly more than control. Active form of MMP-9 was detected only in patients. Although pro-MMP-9 was present in both groups, its level in control group was significantly higher than patients. The heart enlargement was observed in the left, right or both parts. Statistically significant differences in active form of MMP-2 and MMP-9 levels were observed between different groups of heart enlargement (right, left and both parts) compared to control but this difference was not significant considering chambers affected and VHS (vertebral heart score) groups. In conclusion, although there are some changes in serum MMP-2 and MMP-9 levels in canine DCM, it seems that increase of MMP-9 is more prominent than MMP-2 and neither of them were affected by heart enlargement or VHS grade.

Evaluation of modified Ziehl-Neelsen, direct fluorescent-antibody and PCR assay for detection of Cryptosporidium spp. in children faecal specimens

To determine the sensitivity and specificity of routine screening methods for cryptosporidiosis, three methods including conventional modified Ziehl-Neelsen (MZN), direct fluorescent-antibody (DFA) and Nested-PCR assay compared together. To this end, their ability to identify the low concentrations of Cryptosporidium spp. oocysts in children fecal samples was evaluated. The sample population of this study was children under 12 years old who had diarrhea and referred to pediatric hospitals in Tehran, Iran. 2,510 stool specimens from patients with diarrhea were screened for Cryptosporidium oocysts by concentration method and MZN. To determine sensitivity and specificity, Nested-PCR and DFA were performed on 30 positive and 114 negative samples which previously had been proved by MZN. By using the microscopic method, DFA assay and PCR analysis, a total of 30 (1.2 %), 28 (1.1 %) and 32 (1.27 %) positive samples were detected respectively. According to the results, the sensitivity, specificity, and positive and negative predictive values of the Nested-PCR assay were 100 %, compared to 94, 100, 100, and 98 %, respectively, for MZN and 87.5, 100, 100, and 96 %, respectively, for DFA. Results of the present study showed that the Nested-PCR assay was more sensitive than the other two methods and laboratories can use the Nested-PCR method for precise diagnosis of Cryptosporidium spp. However, regarding the costs of Nested-PCR and its unavailability in all laboratories and hospitals, MZN staining on smears has also enough accuracy for Cryptosporidium diagnosis.

Effective, appropriate and simple culture, egg hatching and cryopreserving of the nematode Cheilospirura hamulosa

1. Successful invasion by nematode parasites is associated with several factors including egg hatching at the right time in their hosts. To determine a simple and appropriate medium for culture and egg hatching of the highly pathogenic species of the Acuariidae family, Cheilospirura hamulosa were cultured in three different media. In addition the viability of C. hamulosa eggs was determined after storage in frozen infected gizzards. 2. Eggs removed from the uteri of the female worms in infected gizzards were pooled and washed in distilled water and screened under a stereo dissecting microscope. Eggs were counted and cultured in three different media, nutrient agar, normal saline 0.9% and Bearman, at room temperature. Additionally, 10 infected gizzards were kept at -20°C for 2 and 8 months. 3. After 4-5 d there had been no growth in the nutrient agar medium, whereas 11% of the cultured eggs in the Bearman medium contained larvae 2-3 d after culturing. In 0.9% normal saline medium the two polar knobs appeared on the two poles of the eggs at 2 d post cultivation, and 74% of the eggs contained a larva on the third day. Mature larvae gradually exited from the eggs. 4. Eggs collected from female worms in gizzards frozen at -20°C were cultured in the same three culture media at room temperature. Larvae were visible in the eggs after 2-3 d in the Bearman and 0.9% normal saline media and hatched thereafter. 5. The 0.9% normal saline medium is recommended for egg hatching and cultivation of C. hamulosa due for simplicity, efficacy and cost effectiveness. Moreover, freezing of the infected gizzards at -20°C is proposed for long-term storage of the eggs.

Tolerogenic dendritic cells produced by lentiviral-mediated CD40- and interleukin-23p19-specific shRNA can ameliorate experimental autoimmune encephalomyelitis by suppressing T helper type 17 cells

Down-regulation of soluble or membrane-bound co-stimulatory molecules by RNAi in dendritic cells can prevent the activation of immune responses. Therefore, this study was designed to evaluate the therapeutic efficacy of bone marrow-derived DCs (BMDCs) transduced with lentiviral vectors to permanently expressed shRNA specific for CD40 (CD40LV-DCs) and/or p19 subunit of interleukin (IL)-23 (p19LV-DCs) mRNAs in experimental autoimmune encephalomyelitis (EAE). In-vitro studies showed that double-transduced BMDCs (CD40(+) p19LV-DCs) resemble tolerogenic DCs due to profound down-regulation of CD40, lower expression of proinflammatory cytokines (IL-6 and IL-12), increased IL-10 production and stronger stimulation of myelin oligodendrocyte glycoprotein (MOG)35-55 -specific T cells for production of IL-10 compared with CD40LV-DCs, p19LV-DCs and BMDCs transduced with control lentiviral vector (CoLV-DCs). Moreover, injection of transduced CD40(+) p19LV- BMDCs in EAE mice resulted in more reduction in clinical score, significant reduction in IL-17 or increased production of IL-10 by mononuclear cells derived from the lymph nodes or spinal cord compared with CoLV-DCs-treated EAE mice. In conclusion, simultaneous knock-down of CD40 and IL-23 production by BMDCs may represent a promising therapeutic tool for the treatment of IL-17-dependent autoimmune diseases, including multiple sclerosis.

Self-consistent performance modeling for dual band MIS UV photodetectors based on Si/SiO2 multilayer structure

In this paper, we present a self-consistent theoretical model for a metal-insulator semiconductor (MIS) dual band ultraviolet (UV) photodetector with a modified structure implying an arbitrarily defined insulating potential barrier as its active region. Utilizing our proposed model, the dark and photocurrent density-voltage (J-V) characteristics of MIS UV photodetectors with multi-quantum wells of silicon (MQWs) are calculated. We demonstrate that dark current is reduced in the suggested structure, because the electron-tunneling probability becomes unity at energies coincident with the peak detection wavelength. This is due to the resonant tunneling and decreases at energies that are significantly smaller than this optimum value. In consequence, the number of carriers contributing to the dark current, which have a broad energy distribution at high temperatures, will decrease. It is also shown that the designed structure could detect two individual UV wavelengths, simultaneously. The width of each Si quantum well has been considered at around 1.2 nm, in order to observe these two absorption peaks in the middle and near UV regions of photon spectrum (about 365 nm, 175 nm).

T- and Y-splitters based on an Au/SiO2 nanoring chain at an optical communication band

In this paper, we have utilized Au nanoring chains in an SiO2 host to design certain T-and Y-structures, and expanded it to transport and split the electromagnetic energy in integrated nanophotonic devices operating at an optical communication band (λ≈1550 nm). We compared two structures and tried to choose the best one, with lower losses and higher efficiency at the output branches, in order to split and transport the optical energy. Comparing the different types of nanoparticles corroborates that nanorings have an extra degree of tunability in their geometrical components. Meanwhile, nanorings show strong confinement in near-field coupling, less extinction coefficient, and also lower scattering into the far field during energy transportation at the C-band spectrum. Due to the nanoring's particular properties, transportation losses would be lower than in other nanoparticle-based structures like nanospheres, nanorods, and nanodisks. We demonstrate that Au nanorings surrounded by an SiO2 host yield suitable conditions to excite surface Plasmons inside the metal. Comparison between Y-and T-splitters shows that the Y-splitter is a more suitable alternative than the T-splitter, with higher transmission efficiency and lower losses. In the Y-structure, the power ratio (time-averaged power across the surface) is 24.7%, and electromagnetic energy transportation takes place at group velocities in the vicinity of 30% of the velocity of light; transmission losses are γT=3 dB/655 nm and γT=3 dB/443 nm. In this work, we have applied the finite-difference time-domain method (FDTD) to simulate and indicate the properties of structures.

Accelerated thymocyte maturation in IL-12Rβ2-deficient mice contributes to increased susceptibility to autoimmune inflammatory demyelination

IL-12Rβ2(-/-) mice, which are unresponsive to IL-12, develop severe experimental autoimmune encephalomyelitis (EAE). The mechanisms for enhanced autoimmunity are incompletely understood. We report that in IL-12Rβ2(-/-) mice, thymocytes undergo markedly accelerated maturation. This occurs at the transition from a double positive (DP) to a single positive (SP) phenotype, resulting in higher numbers of CD4 and CD8 SP cells, and to a lesser extent at the transition from double negative (DN) to DP cells. Accelerated maturation is observed in mice injected with anti-CD3 to mimic pre-T-cell receptor stimulation, and also in mice immunized with myelin oligodendrocyte glycoprotein (MOG) peptide to induce EAE.

The role of N53Q mutation on the rat mu-opioid receptor function

Glycosylation of the mu-opioid receptor may play an important role on its function. Using nested PCR, N53Q mutation was prepared in the N-terminal region of the rat mu-opioid receptor cDNA and cloned into the pcDNA3 vector. The plasmids containing the wild-type and mutated receptor cDNA were transfected into the COS-7 cells. Intracellular cAMP was measured in the morphine-treated and untreated transfected cells using an ELISA kit. Plasmid expression was evaluated using X-gal staining. Intracellular concentration of cAMP in the N53Q-mutated cells was not significantly different from the wild-type. The expression of the transfected plasmids was confirmed. Therefore, based on these results, it seems that glycosylation at the N53 site of the rat mu-opioid receptor does not influence the function of this receptor significantly.

Ultrafast low-threshold all-optical switch implemented by arrays of ring resonators coupled to a Mach-Zehnder interferometer arm: based on 2D photonic crystals

Using an array of m x n nonlinear ring resonators (m = 1, 3, 5, and n = 1, 2, 3) coupled to the upper arm of a Mach-Zehnder interferometer (MZI), we have proposed an all-optical switch structure. Using a 5 x 3 array, we have shown the possibility of designing an all-optical switching device with a threshold intensity as low as 15 mW/m(2) and switching window of approximately 35 ps. While using m x 1 arrays, we have achieved switching windows smaller than 10 ps, at the expense of higher switching thresholds, ranging from 37 to 55 mW/m(2). The whole structure is based on a square lattice photonic crystal of lattice constant a = 600 nm, formed by rods of radius r = 90 nm in an air background. The linear rods' refractive index is taken to be the same as that of Si(0.75)Ge(0.25); i.e., n(r) = 3.6, whereas the nonlinear rod's refractive index and Kerr index parameter are taken to be n(0) = 1.4 and n(2) = 10(-14) m(2)/W. The center wavelength at which the nonlinear rings are designed to make the resonance is taken to be lambda(0) = 1550 nm in free space.

Proposal for ultra-high performance infrared quantum dot

In this paper, effect of an introduced defect on electrical and optical properties of quantum box and spherical quantum dot is studied. 3D-self-consistent solution of the Schrödinger-Poisson equations for evaluation of the proposed complex quantum box and analytical solution for spherical quantum dot are used. It is shown that with increasing the defect size and height a considerable enhancement in matrix element, optical nonlinearities (second order, quadratic electro-optic effect and the resonant third order nonlinear susceptibilities), optical linear absorption coefficient ( 4.5 -10 nm, 10(-4) approximately 10(-2) m.V(-1), 10(-12) approximately 10(-9) m(2) / V (2) , 10(-11) approximately 10(-9) m(2) / V(2) and 4.7 x 10(2) approximately 3.8 x 10(4) cm(-1) respectively) and electroabsorption properties associated with intersublevel transition of centered defect quantum dot are examined. Also, it is shown that enhancement of optical nonlinearity is approximately independent of defect position that is so excellent from practical implementation point of view. A THZ-IR photodetector based on resonant tunneling spherical centered defect quantum dot (RT-SCDQD) operating at room temperature is also investigated. Inserting the centered defect in quantum dot increases the dipole transition matrix element and so increases the absorption coefficient considerably (1.05 x 10(6) approximately 7.33 x 10(6)at 83 microm ). Therefore the quantum efficiency in SCDQD structure enhances which leads to increasing the responsivity of the proposed system. The double barrier reduces the dark current. These improvements concludes to ultra high detectivity 5 x 10(16) 2.25 x 10(9) cm Hz (1/2)/W at 83 and 300 degrees K at 83 microm respectively.

Narrowband DWDM filters based on Fibonacci-class quasi-periodic structures

In this paper, we propose a narrowband DWDM filter structure, whose reflection band characteristics, meets the ITU-T standard. The proposed filter structure is based on Fibonacci quasi-periodic structures composed of multilayers with large index differences. Studying the effects of the optical and geometrical parameters of Fibonacci quasi-periodic structures on its filtering properties, we have realized that to achieve the ITU-T standard, we need to cascade two successive structures both with the same generation numbers j=4 and orders n=25 and apodized refractive indices. The apodization process helps to minimize the stop band sidelobes. We have also demonstrated that beside Fibonacci's order, n, the layers dimensions, and their refractive index ratios are the main design parameters.

Motor neuron pathology in experimental autoimmune encephalomyelitis: studies in THY1-YFP transgenic mice

Using adult male C57BL/6 mice that express a yellow fluorescent protein transgene in their motor neurons, we induced experimental autoimmune encephalomyelitis (EAE) by immunization with myelin oligodendrocyte glycoprotein peptide 35-55 (MOG peptide) in complete Freund's adjuvant (CFA). Control mice of the same transgenic strain received CFA without MOG peptide. Early in the course of their illness, the EAE mice showed lumbosacral spinal cord inflammation, demyelination and axonal fragmentation. By 14 weeks post-MOG peptide, these abnormalities were much less prominent, but the mice remained weak and, as in patients with progressive multiple sclerosis, spinal cord atrophy had developed. There was no significant loss of lumbar spinal cord motor neurons in the MOG peptide-EAE mice. However, early in the course of the illness, motor neuron dendrites were disrupted and motor neuron expression of hypophosphorylated neurofilament-H (hypoP-NF-H) immunoreactivity was diminished. By 14 weeks post-MOG peptide, hypoP-NF-H expression had returned to normal, but motor neuron dendritic abnormalities persisted and motor neuron perikaryal atrophy had appeared. We hypothesize that these motor neuron abnormalities contribute to weakness in this form of EAE and speculate that similar motor neuron abnormalities are present in patients with progressive multiple sclerosis.

Mature bone marrow-derived dendritic cells polarize Th2 response and suppress experimental autoimmune encephalomyelitis

Distinct subsets of dendritic cells (DCs) based on the origin, phenotypes, and the nature of the signals that promote DC maturation can determine polarized immune responses of T cells. In this study, DCs were cultured from mouse bone marrow (BM) progenitors in granulocyte-macrophage colony-stimulating factor (GM-CSF). To generate mature DCs (mDCs), lipopolysaccharide (LPS) was used in the culture for 24 h. LPS-stimulated DCs were phenotypically mature, which exhibited strongly upregulated CD40, B7.1, and B7.2 compared to non-LPS-stimulated immature DCs (imDCs). Both mDCs and imDCs expressed high levels of MHC class II but low level of CD54. mDCs produced higher levels of IL-10 and lower IL-12 compared to imDCs. No IFN-gamma or IL-4 was found in both groups. When mDCs were injected intraperitoneally (i.p.) to the mice with experimental autoimmune encephalomyelitis (EAE), the severity of clinical signs and inflammation in the CNS was significantly suppressed compared to imDC-injected mice (p<0.01) and PBS-injected mice (p<0.02). Moreover, lymphocytes from mDC-injected mice produced lower level of IL-12, IFN-gamma, but higher level of IL-10, compared to imDC-injected and non-DC-injected mice. We conclude that BM-mDCs, but not BM-imDCs, promote Th2 differentiation and have the potential for suppression of inflammatory demyelination.