Prospective Randomized Trial Comparing Endoscopic Sphincterotomy Followed by Surgery with Surgery Alone in Good Risk Patients with Choledocholithiasis

Background: Role of endoscopic sphincterotomy (ES) in high risk patients with choledocholithiasis is established but its role in good risk patients is unclear

Polarized release of TCR-enriched microvesicles at the T cell immunological synapse

The recognition events that mediate adaptive cellular immunity and regulate antibody responses depend on intercellular contacts between T cells and antigen presenting cells (APC)1. T cell signaling is initiated at these contacts when surface-expressed antigen receptors (TCR) recognize peptide fragments (antigens) of pathogens bound to Major Histocompatibility Complex molecules (pMHC) on APCs. This, along with engagement of adhesion receptors, leads to the formation of a specialized junction between T cells and APCs, known as the immunological synapse (IS)3, which mediates efficient delivery of effector molecules and intercellular signals across the synaptic cleft2. T cell recognition of pMHC and the adhesion ligand Intercellular Adhesion Molecule-1 (ICAM-1) on supported planar bilayers recapitulates the domain organization of the immunological synapse (IS)4–5, which is characterized by central accumulation of TCR5, adjacent to a secretory domain3, both surrounded by an adhesive ring4–5. Although accumulation of TCR at the IS center correlates with T cell function4, this domain is itself largely devoid of TCR signaling activity5–6, and is characterized by an unexplained immobilization of TCR-pMHC complexes relative to the highly dynamic IS periphery4–5. Here we show that centrally accumulated TCR is located on the surface of extracellular microvesicles that bud at the IS center. Tumor susceptibility gene 101 (TSG101)6 sorts TCR for inclusion in microvesicles, while vacuolar protein sorting 4 (VPS4) 7–8 mediates scission of microvesicles from the T cell plasma membrane. The HIV polyprotein GAG co-opts this process for budding of virus-like particles. B cells bearing cognate pMHC receive TCR from T cells and initiate intracellular signals in response to isolated synaptic microvesicles. We conclude that the immunological synapse orchestrates TCR sorting and release in extracellular microvesicles. These microvesicles deliver transcellular signals across antigen-dependent synapses by engaging cognate pMHC on APC

Self-reactive human CD4 T cell clones form unusual immunological synapses

Recognition of self–peptide-MHC (pMHC) complexes by CD4 T cells plays an important role in the pathogenesis of many autoimmune diseases. We analyzed formation of immunological synapses (IS) in self-reactive T cell clones from patients with multiple sclerosis and type 1 diabetes. All self-reactive T cells contained a large number of phosphorylated T cell receptor (TCR) microclusters, indicative of active TCR signaling. However, they showed little or no visible pMHC accumulation or transport of TCR–pMHC complexes into a central supramolecular activation cluster (cSMAC). In contrast, influenza-specific T cells accumulated large quantities of pMHC complexes in microclusters and a cSMAC, even when presented with 100-fold lower pMHC densities. The self-reactive T cells also maintained a high degree of motility, again in sharp contrast to virus-specific T cells. 2D affinity measurements of three of these self-reactive T cell clones demonstrated a normal off-rate but a slow on-rate of TCR binding to pMHC. These unusual IS features may facilitate escape from negative selection by self-reactive T cells encountering very small amounts of self-antigen in the thymus. However, these same features may enable acquisition of effector functions by self-reactive T cells encountering large amounts of self-antigen in the target organ of the autoimmune disease

Evasion of anti-growth signaling: a key step in tumorigenesis and potential target for treatment and prophylaxis by natural compounds

The evasion of anti-growth signaling is an important characteristic of cancer cells. In order to continue to proliferate, cancer cells must somehow uncouple themselves from the many signals that exist to slow down cell growth. Here, we define the anti-growth signaling process, and review several important pathways involved in growth signaling: p53, phosphatase and tensin homolog (PTEN), retinoblastoma protein (Rb), Hippo, growth differentiation factor 15 (GDF15), AT-rich interactive domain 1A (ARID1A), Notch, insulin-like growth factor (IGF), and Krüppel-like factor 5 (KLF5) pathways. Aberrations in these processes in cancer cells involve mutations and thus the suppression of genes that prevent growth, as well as mutation and activation of genes involved in driving cell growth. Using these pathways as examples, we prioritize molecular targets that might be leveraged to promote anti-growth signaling in cancer cells. Interestingly, naturally-occurring phytochemicals found in human diets (either singly or as mixtures) may promote anti-growth signaling, and do so without the potentially adverse effects associated with synthetic chemicals. We review examples of naturally-occurring phytochemicals that may be applied to prevent cancer by antagonizing growth signaling, and propose one phytochemical for each pathway. These are: epigallocatechin-3-gallate (EGCG) for the Rb pathway, luteolin for p53, curcumin for PTEN, porphyrins for Hippo, genistein for GDF15, resveratrol for ARID1A, withaferin A for Notch and diguelin for the IGF1-receptor pathway. The coordination of anti-growth signaling and natural compound studies will provide insight into the future application of these compounds in the clinical setting

Tumor-Shed PGE2 Impairs IL2Rγc-Signaling to Inhibit CD4+ T Cell Survival: Regulation by Theaflavins

BACKGROUND:Many tumors are associated with decreased cellular immunity and elevated levels of prostaglandin E2 (PGE2), a known inhibitor of CD4+ T cell activation and inducer of type-2 cytokine bias. However, the role of this immunomodulator in the survival of T helper cells remained unclear. Since CD4+ T cells play critical roles in cell-mediated immunity, detail knowledge of the effect tumor-derived PGE2 might have on CD4+ T cell survival and the underlying mechanism may, therefore, help to overcome the overall immune deviation in cancer. METHODOLOGY/PRINCIPAL FINDINGS:By culturing purified human peripheral CD4+ T cells or Jurkat cells with spent media of theaflavin- or celecoxib-pre-treated MCF-7 cells, we show that tumor-shed PGE2 severely impairs interleukin 2 receptor gammac (IL2Rgammac)-mediated survival signaling in CD4+ T cells. Indeed, tumor-shed PGE2 down-regulates IL2Rgammac expression, reduces phosphorylation as well as activation of Janus kinase 3 (Jak-3)/signal transducer and activator of transcription 5 (Stat-5) and decreases Bcl-2/Bax ratio thereby leading to activation of intrinsic apoptotic pathway. Constitutively active Stat-5A (Stat-5A1 6) over-expression efficiently elevates Bcl-2 levels in CD4+ T cells and protects them from tumor-induced death while dominant-negative Stat-5A over-expression fails to do so, indicating the importance of Stat-5A-signaling in CD4+ T cell survival. Further support towards the involvement of PGE2 comes from the results that (a) purified synthetic PGE2 induces CD4+ T cell apoptosis, and (b) when knocked out by small interfering RNA, cyclooxygenase-2 (Cox-2)-defective tumor cells fail to initiate death. Interestingly, the entire phenomena could be reverted back by theaflavins that restore cytokine-dependent IL2Rgammac/Jak-3/Stat-5A signaling in CD4+ T cells thereby protecting them from tumor-shed PGE2-induced apoptosis. CONCLUSIONS/SIGNIFICANCE:These data strongly suggest that tumor-shed PGE2 is an important factor leading to CD4+ T cell apoptosis during cancer and raise the possibility that theaflavins may have the potential as an effective immunorestorer in cancer-bearer

Brittle failure of cold forming dies made of high strength steel

Includes bibliographical references (pages [49]-51)Interference fits between die case, sleeves, and die inserts are critical in the operating life of a tooling. This paper makes a study of die casings made up of Maraging Steel, which failed in fatigue and die casings made up of H13 Steel which failed explosively after a few hours of assembly. The reason for random failure of these casings were investigated which revealed that H13 material had less toughness as compared to that of Maraging Steel. The other reasons were found to be stress corrosion, hydrogen embrittlement, variation in dimensioned tolerances and lack of surface integrity in the assembled components.M.S. (Master of Science

The mechanism of T cell receptor-mediated signal transduction

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Iron N-(2-hydroxy acetophenone) glycinate (FeNG), a non-toxic glutathione depletor circumvents doxorubicin resistance in Ehrlich ascites carcinoma cells in vivo

Multidrug resistance-associated protein 1 (MRP1) reduces intracellular anticancer drug accumulation either by co transporting them with glutathione (GSH) or extruding drug-GSH conjugates outside of the cell. Thus, MRP1 confers multidrug resistance (MDR) and worsen successful chemotherapeutic treatment against cancer. Although the exact mechanism of MRP1 involved in MDR remains unknown, the elevated level of intracellular GSH is considered as a key factor responsible for MDR in cancer. Hence the quest for non-toxic molecules that are able to deplete intracellular GSH has profound importance to subdue MDR. The present preclinical study depicts the resistance reversal potentiality of an iron complex; viz. Ferrous N-(2-hydroxy acetophenone) glycinate (FeNG) developed by us in doxorubicin resistant Ehrlich ascites carcinoma (EAC/Dox) cells. FeNG potentiate cytotoxic effect of doxorubicin on EAC/Dox cells ex vivo and also increases the survivability EAC/Dox bearing Swiss albino mice in vivo as well. Moreover, in vivo administration of FeNG significantly depletes intracellular GSH with ensuant increase in doxorubicin concentration in EAC/Dox cells without alternation of MRP1 expression. In addition, intra-peritoneal (i.p.) application of FeNG in normal or EAC/Dox bearing mice does not cause any systemic toxicity in preliminary trials in mouse Ehrlich ascites carcinoma model. Therefore, the present report provides evidence that FeNG may be a promising new resistance modifying agent against drug resistant cancers

A copper chelate selectively triggers apoptosis in myeloid-derived suppressor cells in a drug-resistant tumor model and enhances antitumor immune response

Myeloid-derived suppressor cells (MDSCs), one of the major orchestrators of immunosuppressive network are present in the tumor microenvironment suppress antitumor immunity by subverting Th1 response in tumor site and considered as a great obstacle for advancement of different cancer immunotherapeutic protocols. Till date, various pharmacological approaches have been explored to modulate the suppressive functions of MDSCs in vivo. The present study describes our endeavor to explore a possibility of eradicating MDSCs by the application of a copper chelate, namely copper N-(2-hydroxy acetophenone) glycinate (CuNG), previously found to be a potential immunomodulator that can elicit antitumorogenic Th1 response in doxorubicin-resistant EAC (EAC/Dox) bearing mice. Herein, we demonstrated that CuNG treatment could reduce Gr-1+CD11b+ MDSC accumulation in ascitic fluid and spleen of EAC/Dox tumor model. Furthermore, we found that CuNG mediated reduction in MDSCs is associated with induction of Th1 response and reduction in Treg cells. Moreover, we observed that CuNG could deplete MDSCs by inducing Fas-FasL mediated apoptotic cell death where death receptor Fas expression is enhanced in MDSCs and FasL is provided by activated T cells. However, MDSC expansion from bone marrow cells and their differentiation was not affected by CuNG. Altogether, these findings suggest that the immunomodulatory property of CuNG is attributed to, at least in part, by its selective cytotoxic action on MDSCs. So, this preclinical study unveils a new mechanism of regulating MDSC levels in drug-resistant cancer model and holds promise of translating the findings into clinical settings

The molecular interaction of a copper chelate with human P-glycoprotein

One of the major reasons for multidrug resistance (MDR) in cancer is the overexpression of P-glycoprotein (P-gp, ABCB1), a drug efflux pump. A novel copper complex, namely, copper (II) N-(2-hydroxyacetophenone) glycinate (CuNG) previously synthesized and characterized by the authors had been tested in this study. In a cell-based assay system with human MDR1 cDNA overexpressed mouse fibroblast NIH MDR1-G185 cell line, we demonstrated that this metal complex can directly interact with this transporter. As CuNG increased cellular accumulation of doxorubicin in P-gp-expressing cells, we presumed that of CuNG may be potential to reverse P-gp-mediated drug resistance probably by lowering the P-gp expression at the protein as well as mRNA level. Interestingly, our studies on UIC2 (a conformation sensitive monoclonal antibody) binding assay indicated the direct interaction of CuNG with P-gp. However, CuNG did not compete for the substrate binding as photoaffinity labeling of P-gp with a substrate analog [125I] iodoarylazidoprazosin ([125I] IAAP) showed approximately twofold increase in [125I] IAAP binding in presence of CuNG. In vitro study showed that CuNG significantly stimulated P-gp-specific ATPase activity in isolated membrane preparations from NIH MDR1-G185 cells. This result further confirmed the CuNG–P-gp direct interaction. This study also demonstrated that CuNG has a drug interaction site different from verapamil-, vinblastine- and progesterone-binding sites on P-gp. Taken together, this is the first report of molecular interaction of any Schiff’s base metal chelate CuNG with human P-gp. This information may be useful to design more efficacious nontoxic metal-based drugs as MDR-reversing agents