Presence Of Con Research Articles

CD4+ T cells show a cytolytic phenotype functions in human visceral leishmaniasis

Abstract Control of Visceral leishmaniasis (VL), a parasitic disease caused by L. donovani, requires robust CD4 +T cells response to control the parasite replication by IFN-γ production and activation of macrophages. Our recent study on transcriptional signature of CD4 +T cell isolated from peripheral blood of active VL patients showed enhanced expression of genes related to cytotoxicity. In present study, we investigated expression of these cytotoxic molecules including granzyme B (GZMB), Granulysin, Perforin and NKG7 on different CD4 +T cell subsets to establish the role of GZMB in regulating CD4 +T cells functional capacity. PBMCs cells were isolated from active and post treated VL patients and endemic controls, and flow cytometry was performed. LAMP assay (CD107b expression) was performed to study the degranulation capacity of CD4 +T cells. Whole blood assay followed by ELISA was performed to measure antigen specific cytokine / GZMB production by CD4 +T cells. We found that activated and degranulating CD4 +T cells (CD38 +CD107 +) had higher expression of GZMB, Granulysin, perforin and NKG-7. Similarly, GZMB level in plasma and antigen stimulated whole blood culture supernatant were significantly elevated in active VL patient compared to post treatment and EC. There was no change is IFN-γ secretion when whole blood culture was stimulated with soluble leishmania antigen in presence of Con-A but a significant decline in IL-6 production was observed. In summary, VL CD4 +T cells show a cytolytic phenotype and further investigations are required to understand their differentiation and function, particularly for promoting anti-parasitic immunity for host protection and effective intervention or therapy. Extramural Program of the National Institute of Allergy and Infectious Diseases, National Institutes of Health (TMRC grant number U19AI074321)

Thelper1 and T helper2 cytokine production patterns in stressed beta2-adrenergic receptor-deficient mice during chlamydia genital infection.

Murine CD4+ T cells have two distinct cytokine secretion patterns to play different functions. We have demonstrated that cold-induced stress (CIS) suppresses the immune system leading to increased intensity of Chlamydia muridaum in mice. We have reported that beta2-adrenergic receptor (b2-AR) knockout (KO) mice resist chlamydia genital infection. However, the cytokine profile of CD4+ T cells is not well explored. This study aimed to determine the cytokine production of Th1 and Th2 types in stressed and non-stressed b2-AR KO mice. We investigated the cytokine production levels of stressed and non-stressed mice during C. muridarum genital infection. Significantly increased production of cytokines was observed in plates pre-coated with anti-CD3/CD28 or in the presence of Con A or LPS. A decrease in the production of IFN-g and IL-2, whereas an increase in the secretion of IL-10, IL-13, and IL-23 in CD4+ T cells of stressed wild-type mice was obtained; however, the secretion of IFN-g and IL-2 was restored in T cells of b2-AR KO mice. Moreover, in vitro proliferation of CD4 T cells in the presence of b2-AR antagonists, ICI 118, 551 stimulated the production of Th1 cytokines, whereas b2-AR agonist, Fenoterol, decreased the production of Th1-type cytokines. Overall, Th1 cytokine responses are reduced in stressed mice suggesting that the cytokine status was polarized toward a Th2 immune response that can be restored by removing b2-AR from immune cells.

Cobalt/nitrogen co-carved carbon nanorod for efficient Fenton-like reaction: Degradation efficacy, reaction mechanism and singlet oxygen generation

• A CoNC Fenton-like catalyst can efficiently degrade organic pollutants. • It is confirmed that 1 O 2 is the dominant active species for degrading organics. • A CoN 2 C 2 ligands structure has the best catalytic activity for peroxymonosulfate activation. • The generation pathway of 1 O 2 is clearly clarified via DFT calculations. • Electrons can be easily transferred from the organics to peroxymonosulfate. The Fenton-like process shows promising potential to generate reactive oxygen species for the remediation of increasingly environmental pollutants. However, the slow development of high-activity catalysts with strong stability and low leaching of metal ions has greatly inhibited scale-up application of this technology. Here, cobalt (Co)/nitrogen (N) atom co-curved carbon nanorod (CoNC) containing highly uniform CoN x active sites is developed as a Fenton-like catalyst for the effective catalytic oxidation of various organics via peroxymonosulfate (PMS) activation with high stability. As confirmed by the experimental results, singlet oxygen ( 1 O 2 ) is the dominant active species for the degradation of the organics, with a proportion of 100%. Furthermore, density functional theory calculations indicate that CoN 2 C 2 is the most effective ligand structure with more negative adsorption energy for PMS and the shortest length Co–O bond, while the most reasonable generation pathway for 1 O 2 was CoN 2 C 2 –PMS → CoN 2 C 2 –OH* → 2O* → 1 O 2 . Further studies demonstrate that the electron can be transferred from the highest occupied molecular orbitals of the organics to the lowest unoccupied molecular orbitals of the PMS via CoN 2 C 2 action. In addition, the CoNC presents strong resistance to inorganic ions and natural organic matter in the Fenton-like catalysis process. The presence of CoN 2 C 2 active centre can significantly shorten the migration distance of the 1 O 2 generated from PMS activation, which further enhances the Fenton-like catalytic activity in terms of mineralising various organic contaminants with high efficiency over a wide pH range.

Multifunctional Alternating “Bitter-Sweet” Macromolecular Architecture

The design and synthesis of a multifunctional macromolecular architecture featuring alternating cholic acid (CA) and glucose pendants in a polymer side-chain is reported. The target architecture was prepared by reversible addition–fragmentation chain-transfer copolymerization of styrene-conjugated CA (the bitter monomer) and acetyl-protected glucose appended maleimide (the sweet monomer) using the polyethylene glycol-conjugated chain transfer agent. Removal of the acetates resulted in amphiphilic “bitter-sweet” alternating copolymers that were self-assembled in aqueous media having CA containing bitter core and sugar-coated sweet shell. Dynamic light scattering measurements in water, field emission scanning electron microscopy, and transmission electron microscopy confirmed the formation of 40 to 75 nm sized micellar nanoscaffolds, depending on the chain-length of the copolymers. The nanoparticles successfully encapsulated hydrophobic molecules as witnessed via fluorescence spectroscopy using Nile red as an exemplary guest. Interestingly, the alternating copolymer recognized β-cyclodextrin (β-CD) through the formation of inclusion complexes with lateral cholate moieties in the polymer as evident from 2D NMR and nuclear Overhauser effect experiments. It is worth noting that the polymer and its inclusion complex were found to be capable of recognizing Concanavalin A (Con A), as shown by turbidimetric assay and isothermal titration calorimetry. Interestingly, the inclusion complex of the alternating copolymer showed significantly higher autofluorescence in the presence of Con A with respect to that of un-complexed one. Thus, the present study offers a simple way to prepare a multifunctional alternating copolymer having hydrophobic molecule encapsulation, inherent fluorescence, inclusion complex formation with β-CD, and lectin recognition capabilities.

Low temperature mullite forming pre-ceramic resins of high ceramic yield for oxide matrix composites

Monophasic mullite precursors, namely aluminosiloxanes were synthesized by a novel synthetic route, in which co-hydrolysis and condensation of aluminium tri secbutoxide and tetraethoxy silane was achieved in presence of con. HCl in a non-polar medium. Aluminosiloxanes were characterized by FT-IR, NMR, and elemental analyses. Spectral analysis confirms the presence of Si-O-Al bonds in all the samples and also validates the incorporation of more aluminium via Si-O-Al bonds with increasing Al/Si mole ratio in the precursor. These FT-IR and NMR data also attest the precursor level homogeneity in all the samples. The aluminosiloxanes are obtained as low viscous resins and are capable of giving high ceramic residue qualifying them as ceramic matrix precursors for CMCs. The effect of Al/Si ratio on the ceramic conversion was studied. All the precursors showed the formation of mullite at 1000 °C. This low temperature mullite formation is a key factor in developing oxide CMCs without fiber damage. The results obtained from the study show that the composition of the ceramic can be controlled between a silica rich mullite phase and near-stoichiometric mullite phase by suitably selecting the Al/Si monomer feed ratio of the precursors. This aspect provides a greater scope for designing application-specific ceramic matrices for space applications.

ConA-Coated Liposomes as a System to Delivery β-Lapachone to Breast Cancer Cells.

Target treatment using site-specific nanosystems is a hot topic for treating several diseases, especially cancer. The study was set out to develop site-specific liposomes using ConcanavalinA (ConA) to target β- lapachone(β-lap) to human breast cancer cells. Liposomes were prepared and characterized according to diameter size, zeta potential, ConA conjugation(%) and β-lap encapsulation efficiency (%). Isothermal Titration Calorimetry evaluated the binding energy between the biomolecules, which compose of the liposomes. ConA avidity was assessed before and after conjugation. Cytotoxicity was evaluated, and fluorescence microscopy was performed to investigate the influence of ConA influenced on MCF-7 uptake. Uncoated and ConA-coated liposomes presented size, and zeta potential values from 97.46 ± 2.01 to 152.23 ± 2.73 nm, and -6.83 ± 0.28 to -17.23 ±0.64 mV, respectively. Both ConA conjugation and β-lap encapsulation efficiency were approximately 100%. The favorable and spontaneous process confirmed the binding between ConA and the lipid. Hemagglutination assay confirmed ConA avidity once Lipo-ConA and Lipo-PEG-ConA were able to hemagglutinate the red blood cells at 128-1 and 256-1, respectively. Lipo-ConA was not cytotoxic, and the site-specific liposomes presented the highest toxicity. ConA-coated liposomes were more internalized by MCF7 than uncoated-liposomes. Therefore, the presence of ConA on the surface of liposomes influenced MCF7 uptake, in that way could be used as a promising site-specific system to target β-lap to cancer cells.

Plant neighborhood shapes diversity and reduces interspecific variation of the phyllosphere microbiome.

Microbial communities associated with plant leaf surfaces (i.e., the phyllosphere) are increasingly recognized for their role in plant health. While accumulating evidence suggests a role for host filtering of its microbiota, far less is known about how community composition is shaped by dispersal, including from neighboring plants. We experimentally manipulated the local plant neighborhood within which tomato, pepper, or bean plants were grown in a 3-month field trial. Focal plants were grown in the presence of con- or hetero-specific neighbors (or no neighbors) in a fully factorial combination. At 30-day intervals, focal plants were harvested and replaced with a new age- and species-matched cohort while allowing neighborhood plants to continue growing. Bacterial community profiling revealed that the strength of host filtering effects (i.e., interspecific differences in composition) decreased over time. In contrast, the strength of neighborhood effects increased over time, suggesting dispersal from neighboring plants becomes more important as neighboring plant biomass increases. We next implemented a cross-inoculation study in the greenhouse using inoculum generated from the field plants to directly test host filtering of microbiomes while controlling for directionality and source of dispersal. This experiment further demonstrated that focal host species, the host from which the microbiome came, and in one case the donor hosts' neighbors, contribute to variation in phyllosphere bacterial composition. Overall, our results suggest that local dispersal is a key factor in phyllosphere assembly, and that demographic factors such as nearby neighbor identity and biomass or age are important determinants of phyllosphere microbiome diversity.

The efficient method for the electrochemical oxidation of benzyl alcohol to benzaldehyde using potassium iodate in a biphasic medium

For the preparation of benzaldehyde, a biphasic electrolysis technique has been devised. The reaction between benzyl alcohol and potassium iodate in the presence of con. sulphuric acid gives benzaldehyde. The product benzaldehyde was characterized by UV, FTIR, and 1H NMR spectroscopy, and the percentage of product yield were calculated by HPLC. Various electrochemical oxidation methods were used to optimize the electrochemical experimental parameters such as current density, charge passed, different acids, different solvents, agitation, various mediators, and various medium to achieve a high benzaldehyde (97%) yield. This electrolysis oxidation is explained by a radical mechanism. For the oxidation of substituted benzyl alcohol, the optimum conditions were extended and promising yields were obtained.

Structural Arrangement Produced by Concanavalin A Binding to Homomeric GluK2 Receptors.

Kainate receptors are members of the ionotropic glutamate receptor family. They form cation-specific transmembrane channels upon binding glutamate that desensitize in the continued presence of agonists. Concanavalin A (Con-A), a lectin, stabilizes the active open-channel state of the kainate receptor and reduces the extent of desensitization. In this study, we used single-molecule fluorescence resonance energy transfer (smFRET) to investigate the conformational changes underlying kainate receptor modulation by Con-A. These studies showed that Con-A binding to GluK2 homomeric kainate receptors resulted in closer proximity of the subunits at the dimer–dimer interface at the amino-terminal domain as well as between the subunits at the dimer interface at the agonist-binding domain. Additionally, the modulation of receptor functions by monovalent ions, which bind to the dimer interface at the agonist-binding domain, was not observed in the presence of Con-A. Based on these results, we conclude that Con-A modulation of kainate receptor function is mediated by a shift in the conformation of the kainate receptor toward a tightly packed extracellular domain.

Immunomodulatory properties of enzymatic extract of Stichopus japonicus on murine splenocytes

Red sea cucumber Stichopus japonicus is an invertebrate animal inhabiting in coasts of Korea, China, and Japan. They are traditionally used for food and medicine and well known for their distinctive biologically and pharmacologically important compounds. We investigated the effect of amyloglucosidase (AMG) enzymatic extracts of S. japonicus (AESJ) on the proliferation and cytokine secretion of murine splenocytes stimulated with concanavalin A (Con A). AESJ enhanced the proliferation of splenocytes and the production of IL-2 (Th1 cytokine), IL-1β (Th1 promoting cytokine), and IL-4, IL-10 (Th2 type cytokines) when treated alone. However, under Con A stimulation, AESJ suppressed the proliferation of splenocytes, attenuated the secretion of IL-2, IL-4, IL-10, and enhanced IL-1β secretion. These results suggest that AESJ exhibits immunomodulatory effect by moderating the proliferation of splenocytes and the secretion of IL-2, IL-1β, IL-4, and IL-10 differently depending on the absence and presence of Con A stimulation. These data evidence the immunomodulatory potential of AESJ, which can be further developed into a functional food mediating homeostasis.

Diabetes potentiates ROS production in granulocytes from patients with chronic kidney disease

Background: Type 2 diabetes (DM2) and chronic kidney disease (CKD) are inflammatory pathologies. Diabetes is characterized by hyperglycemia and CKD by the gradual and irreversible loss of kidney function. Both diseases develop oxidative stress, and reactive oxygen species (ROS) play a pivotal role in the pathogenesis. This study aimed to determine ROS production by granulocytes from renal patients (CKD) with or without diabetes. Methods: Granulocytes from patients with DM2, CKD, CKD-DM2, and healthy controls were purified using the Ficoll-Hypaque gradient method. Granulocyte ROS generation in the absence or the presence of PDB (an activator of NADPH-oxidase) or Concanavalin A (Toll- receptor 3,9 activator) was evaluated in a luminol-dependent chemiluminescence method. The cell-free DNA in the serum of DM2, CKD, and CKD-DM2 patients was measured by the fluorescence method before and after hemodialysis. Results: Our results show a significant increase in ROS production by granulocytes from patients with CKD, DM2, and CKD-DM2 compared to healthy control (p<0.05). CKD-DM2 group produced the most significant ROS levels with or without NADPH-oxidase activation. ROS production showed a significant increase in the presence of ConA. In contrast, mitochondrial (internal) ROS showed a different ROS response. DNA extrusion was higher in the CKD-DM2 group after hemodialysis suggesting cell death. Conclusion: The results demonstrated that CKD-DM2 patients produced high ROS generation levels and increased DNA extrusion after hemodialysis. It may suggest that CKD-DM2 disease is more severe and has a worse clinical prognosis.

Royal jelly alleviates the detrimental effects of aging on immune functions by enhancing the in vitro cellular proliferation, cytokines, and nitric oxide release in aged human PBMCS

Aging strongly delays the immunity. Our research aims to assess the in vitro effects of royal jelly (RJ) on the immune function of aged PBMCs. PBMCs were obtained from 10 healthy aged and young donors by the gradient density centrifugation method and further cultured in RPMI-1640 medium supplemented with or without RJ in the presence of Con A. Cell proliferation was assessed by MTT assay along with the measurement of interleukins, Nitric oxide (NO), Glutathione (GSH), and Malondialdehydes (MDA). Our results showed that RJ improved PBMCs proliferation significantly in the elderly subjects, accompanied by the increase in NO (p=.001) and the release of IL-2, IL-4, and IL-6 cytokines. RJ also increased the intracellular GSH (p= .001) and MDA (p=.001) levels in aged PBMCs. In young subjects, RJ enhanced PBMCs proliferation potency, IL-4, IL-6, GSH, and intracellular MDA levels but with a concomitant decrease in NO and IL-2 cytokine secretion as compared with non RJ-treated cells. In conclusion, RJ restored functions of the aged PBMCs as well as the young control subjects, indicating a beneficial effect on immune status during the aging process. PRACTICAL APPLICATIONS: Royal jelly is a well-known edible dietary compound, used traditionally to treat many diseases throughout the world. Since antiquity, it was shown to have medicinal importance. The immuno-enhancing potential of this food was largely and scientifically established by the lipid and protein fractions. The present study illustrates the anti-aging and stimulatory effects of the fresh RJ whole extract, from local Algerian honey bee: Apis mellifera intermissa, on the immunity of aged men. This study provides the experimental evidence supporting anti-immunosenesence effects of royal jelly. RJ supplementation can be used in the old age management and human age-related complications, especially, associated with the weaknesses of the immune response.

Chemotaxis behaviour of Steinernema carpocapsae in response to Galleria mellonella (L.) larvae infected by con- or hetero-specific entomopathogenic nematodes

ABSTRACT Entomopathogenic nematodes (EPNs) infect insects and reproduce within the host cadaver. The nematodes use chemotaxis to assist in host-finding. However, the chemotaxis of nematode species in response to insects previously infected by con- and hetero-specific EPN in a sand context has rarely been reported. Our aim was to address the response of Steinernema carpocapsae All (Sc) to Galleria mellonella cadavers infected by con- or hetero-specific EPNs (Heterorhabditis bacteriophora HB1, S. feltiae SN, S. rarum 17 C&E) in sand via chemotaxis assays. Additionally, the effect of different time points post-infection was also evaluated. Results indicated that previously infected G. mellonella larvae repelled infective juveniles (IJs) of Sc (p < 0.05) regardless of the time point post-infection and EPN species (con- or hetero-specific) and had a lower chemotaxis index as compared to that of no larvae addition in both sides. Moreover, it was found that for each of four tested EPN species, EPNs infected insect cadavers released dimethyl disulphide, which was identified by solid-phase microextraction (SPME) coupled to gas chromatography–mass spectrometry (GC–MS). We found that dimethyl disulphide acted as a repellent to Sc infective juveniles and reached a significant effect at the level of 0.106 mol/L. Our findings could provide a better understanding of movement behaviour of EPN infective juveniles in response to insect resources in the presence of con- or hetero-specific EPNs.

Pharmacological Properties of Bioactive Extracts from the Rhizome of Aristolochia longa L

Aristolochia longa is a medicinal plant well known in Moroccan folk medicine for its activity against constipation, intestinal infections and skin diseases. The present study was performed to evaluate in vitro and in vivo immunomodulatory and cytotoxic activities of aqueous and protein extracts of A. longa. The in vitro immunomodulatory results showed that aqueous extract at 0.1 mg/mL enhanced T-lymphocyte cells proliferation in the presence of ConA. While, in the presence of ConA and PMA, the protein extract at 0.1 mg/mL induced a significant decrease of T-lymphocytes and splenocytes proliferation. Both extracts were found to exhibit a significant diminution in phagocytic capacity and macrophage cells proliferation. They also induced a significant decline in the non-specific and specific humoral immune response. The protein chromatography separation was used to isolate two major fractions (F1: 75KDa and F2: 5 KDa) which showed an inhibitory effect on all studied immune cells. The in vivo immunomodulatory response of aqueous and protein extracts have equally evoked a significant dose dependent suppressor effect on total leukocyte count including the lymphocytes, monocytes and granulocytes, whereas the LD50 was 1.26 g/kg by intraperitoneal route. A. longa extracts also demonstrated apoptotic effects by about 9 to 11% against normal immune cells which confirmed the cytotoxic effects of both extracts. In conclusion, Aristolochia longa extracts exerts immunosuppression activities in vitro and in vivo, have cytotoxic effects in vivo explained by the apoptotic properties of aqueous and protein extracts against normal immune.

Female false black widow spiders,Steatoda grossa,recognize webs based on physical and chemical cues

AbstractFemales of the false black widow,Steatoda grossaCL Koch (Araneae: Theridiidae), invest significant energy and time weaving cobwebs. We tested the hypothesis thatS. grossafemales select sites for their webs based, in part, on the presence of con‐ or heterospecific webs, sensing both physical and chemical web cues. In bioassays, we offered femaleS. grossaa choice between an empty control frame and a frame bearing the web of a conspecific female or that of a female common house spider,Parasteatoda tepidariumCL Koch (Araneae: Theridiidae), recording (1) the time she spent, and (2) the time she spent inactive (a proxy for settling behaviour) on each frame. We also tested the effect of (1) silk micro‐ and macrostructure (wrapped‐up silk or intact web, each semiochemical‐deprived), (2) plastic webs, and (3) silk semiochemical extract on the responses ofS. grossafemales. Females settled on both con‐ and heterospecific webs and chose test stimuli based on their chemical and physical characteristics. Even plastic webs in cobweb‐like arrangement readily prompted settling behaviour by females. Our results suggest that web architecture, rather than web silk, mediates settling responses by femaleS. grossaon pre‐existing webs which may provide structural support for a new web and indicate habitat suitability.

Abstract 4701: Verteporfin inhibits surface PD-L1 expression in triple-negative breast cancer (TNBC) cells

Abstract Background: Programmed death ligand 1 (PDL1) is commonly expressed on the surface of many tumor cells, including breast cancer. The activity of tumor-infiltrating lymphocytes (TIL) is inhibited by PDL1. High PD-L1 basal cells (particularly basal B) overexpress genes involved in invasion, motility, and chemoresistance (Soliman et al., 2014). Targeting and blocking PD-L1 may enhance eradication of aggressive breast cancer cells by the immune system. Verteporfin (VP), a photosensitizer used to treat macular degeneration, was found to inhibit PD-L1 expression in a high-throughput screen. Studies demonstrated VP inhibits YAP activation by disrupting YAP-TEAD interactions and preventing YAP induced oncogenic growth (Zhang et al., 2016). Here we demonstrate the inhibitory effect of VP on PD-L1 expression in TNBC cell lines. Methods: MDA-MB-231 cells co-cultured with human PBMCs were treated with VP (Sigma) in presence of concanavalin A (ConA) and analyzed using flow cytometry to study levels of CD8+IFNg+ cells. TNBC cell lines (MDA-MB-231, BT-20, HCC-1143, Hs-578T) were treated with VP at doses ranging from 1µM-10µM for 24 hrs. The cells were processed for flow cytometry, Western blot and RT-PCR to check PD-L1 in mechanistic studies looking at manipulation of YAP pathway genes. Results: When MDA-MB-231 cells were co-cultured with normal human PBMCs in the presence of ConA, the CD8+IFNg+ stained cells were reduced compared to PBMC + ConA alone. Interestingly, in the group treated with VP, rescue of CD8+IFNg+ cells was observed. Moreover, MDA-MB-231, BT-20, HCC-1143 and Hs-578T TNBC cells treated with VP showed a significant dose-dependent inhibition of PD-L1 expression by flow cytometry. Western blot analysis also showed complete clearance of PD-L1 protein band with the lowest dose (1µM) used. However, RT-PCR analysis did not show a significant fold change in mRNA levels of PD-L1 in MDA-MB-231 treated cells. Surprisingly, mechanistic studies performed by silencing YAP1, E2F1, and TBK1 in MDA-MB-231, BT-20 and HS-578 T showed a decline in PD-L1 in E2F1 silenced cells, highlighting a plausible role of E2F1-PDL1 signaling axis. However, no change in PD-L1 expression was seen in cells silenced with YAP1 and TBK1. Further, chromatin-immunoprecipitation assay demonstrated E2F1 binding to PD-L1 promoter. Conclusion: Our data so far demonstrate that verteporfin treatment leads to inhibition of PD-L1 in TNBC cell lines and improvement in CD8+IFNg+ cells, indicating that VP might have potential for treatment approaches. Our study warrants further attention towards understanding the mechanism of action of VP in inhibiting PD-L1 and the role of E2F1 in the process. Citation Format: Fatema Khambati, Neha Jaiswal, Srikumar Chellappan, Hatem Soliman. Verteporfin inhibits surface PD-L1 expression in triple-negative breast cancer (TNBC) cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4701.

Effect of Oxidizing Agents on the Expansion Characteristics of Natural Graphite

In an attempt to study the expansion characteristics of natural graphite in presence of two different oxidizing agents in concentrated acid medium, potassium permanganate and potassium dichromate have been chosen. Under identical reaction conditions, for the same concentrations of oxidizing agents, the expansion of natural graphite in presence of potassium permanganate - con. sulphuric acid mixture has been found to be higher when the heat treatment temperature is varied from 400 °C to 1030 °C. The expanded volume of natural graphite is observed to be four times greater in presence of potassium permanganate/con.sulfuric acid mixture when compared to potassium dichromate in presence of con. sulfuric acid. Also, at 400 °C, potassium permanganate in con. sulfuric acid treated natural graphite resulted in appreciable expansion which has not been observed in the case of potassium dichromate added graphite in presence of con. sulfuric acid. The XRD analysis clearly proved that the crystallite size of natural graphite after intercalation of sulfuric acid decreases and upon further heat treatment, the decrease in crystallite size is appreciable. The full width at half maximum (FWHM) of the most prominent (002) peak of graphite increases with heat treatment temperature even at 500 °C. The optical microscope images very clearly prove the formation of more fluffy structure after intercalation of acid followed by heat treatment at 700 °C. The formation of graphite nanosheets has been proved through FESEM images when the synthesized expanded graphite is sonicated in acetone for few minutes. The present study clearly reveals the possibility of optimizing reagents concentrations and reaction time so that maximum expansion can be obtained.

Umbelliprenin induced both anti-inflammatory and regulatory cytokines in C57/BL6 mice.

Objective(s):Umbelliprenin is a prenyloxy-coumarin with pharmacologically polyvalent activity. Several studies have shown Several studies have been shown its anti-inflammatory, anti-tumor, antioxidant, and antigenotoxic activities. However, the exact mechanism of action of this compound on the immune response has not yet been shown. Here, we investigated umbelliprenin effects on the predominance of Th1 and Th2 responses in normal C57/BL6 mice.Materials and Methods:Umbelliprenin (2.5 mg/200 µl IP) were administered to six C57/BL6 mice every other day for 8 days. Paraffin and PBS-injected mice were enrolled as solvent and control groups, respectively (n=6 mice/group). IL-10, IFN-γ, and IL-4 levels were determined in sera and also in splenocytes culture supernatants in the presence of Con A (3 µg/ml) after 72 hr. H&E staining of paraffin embedded blocks was performed for lung and liver tissues of mice.Results:Umbelliprenin could significantly increase the secretion of IFN-γ and IL-4 in sera and IL-10 in splenocytes cultures. Comparison of IFN-γ/IL-4 in the sera and splenocytes culture supernatants showed lower ratios in umbelliprenin treated mice than in solvent and untreated groups.Conclusion:The in vivo study showed that umbelliprenin could induce anti-inflammatory responses via the predominance of Th2 cells and some regulatory responses in C57/BL6 mice.

The sympathetic nervous system mechanism of exendin-4 in respect of modulating T cell- mediated immune response to severe burns in mice

Objective To investigate the potential effect of glucagon-like peptide-1 (GLP-1) analogue exendin-4 (Ex-4) on immune function of T lymphocytes via neuroendocrine modulation mechanism in mice following severe burns. Methods Male BALB/C mice were randomly(ramdam number) divided into thermal injury group (n=50) and sham-thermal group (n=30). The thermal injury model was made by exposing the back skin of 15% total body surface area (TBSA) to 95 ℃ water for 7 seconds, while in sham-thermal model the mice were immersed in 37 ℃ water instead. The expression of GLP-1 receptor (GLP-1R) was determined in sorted CD4+ T cells from normal mice by immunofluorescence method. In ex vivo experiment, the mice were sacrificed at 24 h post-burn, then the mononuclear cells (MNC) from spleen were separated from both groups and cultured in RMPI 1640 with 10%FCS (fetal calf serum) in presence of ConA (concanavalin A, 5 μg/mL). Cells were pretreated with catecholamine receptor antagonist propranolol (prop) for 1 hour, followed by consecutive dose of Ex-4 for another 48 h. In in vivo experiment, prop (30 mg/kg) was i. p. injected 30 minutes before thermal injury, then Ex-4 (2.4 nmol/kg) was injected i. p. immediately after scalding. Mice were sacrificed at 6 h and 24 h after thermal injury, then the serum and the spleens were collected. Results GLP-1R was expressed on splenic CD4+ T cells from normal mice. Ex-4 exerted no marked effect on the functions of T cells in terms of proliferation and IL-2 secretion at all doses examined ex vivo, which was not affected by pretreatment with prop. In vivo, T cell functions were suppressed by Ex-4 in thermal mice (P<0.05), but was restored by pretreatment with prop. Regardless of ex vivo or in vivo, Ex-4 could induce T cells switched to Th2 response (P<0.05). Moreover, the Th2 switch by Ex-4 was greatly potentiated by prop intervention in thermal mice in vivo other than ex vivo. Norepinephrine level was increased and epinephrine was decreased by Ex-4 in thermal mice. Both norepinephrine and epinephrine levels were obviously enhanced by pretreatment with prop. Conclusions Ex-4 can inhibit the proliferation and IL-2 secretion of splenic T lymphocytes through the sympathetic nervous system, however, it might induce Th2 switch from Th cells by acting directly on GLP-1R. Key words: Burn injury; Glucagon-like peptide-1; T lymphocyte; Immune response; Sympathetic nervous system

Differential effects of palmitoleic acid on human lymphocyte proliferation and function.

BackgroundPalmitoleic acid (PA) is a n-7 monounsaturated fatty acid (MUFA) secreted by adipose tissue and related to decreased insulin resistance in peripheral tissues. Evidences have been shown that PA also decreased proinflammatory cytokine expression in cultured macrophages. Although studies have shown that other fatty acids (FAs) modulate several lymphocyte functions, the specific effect of PA on these cells is unknown. The aim of the present study was to evaluate the possible influence of PA on activation and differentiation of human lymphocytes in comparison to oleic acid (OA).MethodsHuman lymphocytes were isolated from peripheral blood of health men and cultured in the presence of growing concentrations of PA or OA (5 to 200 μM), for 24 h. After that, cells were collected and cytotoxicity evaluated by flow cytometry. Then, we analyzed proliferative capacity in lymphocytes treated with non toxic concentrations of PA and OA (25 and 50 μM, respectively), in the presence or absence of concanavalin A (ConA). The Th1/Th2/Th17 cytokine production was determined by the Cytometric Bead Array. CD28 and CD95 surface expression and T regulatory cell percentage were determined by flow cytometry.ResultsWe observed that PA is toxic to lymphocytes above 50 μM. PA promoted a decrease of lymphocyte proliferation stimulated by ConA in both concentrations. PA also decreased CD28 externalization and increased CD95. On the other hand, OA did not alter these parameters. In the same way, PA reduced IL6, IFN-gamma, TNF-alpha and IL17A production in both concentration and IL2 only at 50 μM (in the presence of ConA). OA promoted IFN-gamma reduction in both concentrations and an increase of IL-2, IL4 and IL10 at 25 μM. Both fatty acids decreased the percentage of T regulatory cells.ConclusionIn conclusion, PA promoted a suppressive effect on lymphocyte proliferation characterized by a decrease of Th1 and Th17 response, and co-stimulatory molecule (CD28). However, OA increased lymphocyte proliferation through IL2 production and Th2 response. These results also show a more suppressive effect of PA on lymphocytes in comparison to OA.