Co-Graft of Allogeneic Immune Regulatory Neural Stem Cells (NPC) and Pancreatic Islets Mediates Tolerance,while Inducing NPC-Derived Tumors in Mice

Background

Data available on the immunomodulatory properties of neural stem/precursor cells (NPC) support their possible use as modulators for immune-mediated process. The aim of this study was to define whether NPC administered in combination with pancreatic islets prevents rejection in a fully mismatched allograft model.

Methodology/Principal Finding

Diabetic Balb/c mice were co-transplanted under the kidney capsule with pancreatic islets and GFP⁺ NPC from fully mismatched C57BL/6 mice. The following 4 groups of recipients were used: mice receiving islets alone; mice receiving islets alone and treated with standard immunosuppression (IL-2Rα chain mAbs + FK506 + Rapamycin); mice receiving a mixed islet/NPC graft under the same kidney capsule (Co-NPC-Tx); mice receiving the islet graft under the left kidney capsule and the NPC graft under the right kidney capsule (NPC-Tx). Our results demonstrate that only the co-transplantation and co-localization of NPC and islets (Co-NPC-Tx) induce stable long-term graft function in the absence of immunosuppression. This condition is associated with an expansion of CD4⁺CD25⁺FoxP3⁺ T regulatory cells in the spleen. Unfortunately, stable graft function was accompanied by constant and reproducible development of NPC-derived cancer mainly sustained by insulin secretion.

Conclusion

These data demonstrate that the use of NPC in combination with islets prevents graft rejection in a fully mismatched model. However, the development of NPC-derived cancer raises serious doubts about the safety of using adult stem cells in combination with insulin-producing cells outside the original microenvironment.     

Urachal tumour: case report of a poorly understood carcinoma

Background

Synchronous midgut carcinoids with gastrointestinal adenocarcinoma are a rare but recognised association.

Case presentation

The patient, a 74 year old woman, underwent anterior resection for a low rectal adenocarcinoma. Intra-operatively 3 serosal deposits of tumour were noted in the distal ileum. Histology revealed these to be ileal carcinoids.

Conclusion

During resection of a gastrointestinal tumour, a thorough inspection of the abdominal cavity should be undertaken to investigate the possibility of metastatic secondaries or a synchronous tumour as is reported in this case.     

Responsiveness of the interrenal tissue of Jundiá (Rhamdia quelen) to an in vivo ACTH test following acute exposure to sublethal concentrations of agrichemicals

As in many aquatic environments, pollution is a widespread problem in Southern Brazil. In our previous work, we demonstrated that sublethal contamination with some agrichemicals impairs the capacity of fishes to elevate cortisol levels in response to an additional acute stressor. In earlier experiments, the experimental design did not allow us to conclude where this effect occurs. In the present work, we used the adrenocorticotropic hormone (ACTH) challenge test to help us identify if the impairment occur in the interrenal tissue. For this purpose, five experiments were conducted, each with one specific agrichemical (methyl-parathion, atrazine+simazine, atrazine, tebuconazole, and glyphosate) in sublethal concentrations of 16.6% of the LC(50-96h), as previously determined. Fish were subjected to the ACTH challenge test protocol as follows: group 1, were non-injected and maintained as the specific control group; group 2 received an injection of the vehicle alone (the saline group); and group 3 receive an injection of ACTH. One hour later, blood samples were taken from the caudal plexus, using sterile syringes. In all specific control groups, the injection of ACTH induced a strong rise in plasma cortisol, compared with the fish injected only with the vehicle and the non-injected group. Fish exposed to methyl-parathion and tebuconazole did not elevate cortisol in response to the ACTH injection, with values significantly lower than the control fish. Fish exposed to sublethal concentrations of atrazine+simazine, atrazine, and glyphosate showed a rise in plasma cortisol very similar to the control fish. We conclude that the ACTH challenge test revealed that R. quelen exposed to sublethal concentrations of tebuconazole and methyl-parathion had a reduced ability to elevate plasma cortisol in response to an intraperitoneal (i.p.) injection of exogenous ACTH, indicating that the interrenal tissue is the site of the impairment within the HPI axis. These ACTH challenge tests also revealed that the impairment of the cortisol response verified in fish exposed to atrazine+simazine and glyphosate, as shown in our previous work, seems to be related to steps of cortisol secretion in higher levels within the HPI axis.     

MF59?-Adjuvanted H5N1 Vaccine Induces Immunologic Memory and Heterotypic Antibody Responses in Non-Elderly and Elderly Adults

Background

Pathogenic avian influenza virus (H5N1) has the potential to cause a major global pandemic in humans. Safe and effective vaccines that induce immunologic memory and broad heterotypic response are needed.

Methods and Findings

Healthy adults aged 18–60 and >60 years (n = 313 and n = 173, respectively) were randomized (1∶1) to receive two primary and one booster injection of 7.5 μg or 15 μg doses of a subunit MF59-adjuvanted H5N1 (A/Vietnam/1194/2004) (clade 1) vaccine. Safety was monitored until 6 months after booster. Immunogenicity was assessed by hemagglutination inhibition (HI), single radial hemolysis (SRH) and microneutralization assays (MN). Mild injection-site pain was the most common adverse reaction. No serious adverse events relating to the vaccine were reported. The humoral immune responses to 7.5 μg and 15 μg doses were comparable. The rates for seroprotection (HI>40; SRH>25mm²; MN ≥40) after the primary vaccination ranged 72–87%. Six months after primary vaccination with the 7.5 μg dose, 18% and 21% of non-elderly and elderly adults were seroprotected; rates increased to 90% and 84%, respectively, after the booster vaccination. In the 15 μg group, seroprotection rates among non-elderly and elderly adults increased from 25% and 62% after primary vaccination to 92% and 88% after booster vaccination, respectively. A heterologous immune response to the H5N1/turkey/Turkey/05 strain was elicited after second and booster vaccinations.

Conclusions

Both formulations of MF59-adjuvanted influenza H5N1 vaccine were well tolerated. The European Union requirement for licensure for pre-pandemic vaccines was met by the lower dose tested. The presence of cross-reactive antibodies to a clade 2 heterologous strain demonstrates that this vaccine may be appropriate for pre-pandemic programs.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00311480","term_id":"NCT00311480"}}NCT00311480     

Fructose production by chicory inulin enzymatic hydrolysis: A kinetic study and reaction mechanism

In this paper, a reaction scheme for fructose production by inulin enzymatic hydrolysis is proposed, taking into account the possibility of dealing with a mixture of enzymes acting on a mixture of polymers as substrate. The scheme is subsequently simplified to obtain a stoichiometric relationship between the fructose product and the reacted substrate. The former may be measured by HPLC, while the latter is the subject of kinetic investigations. Our proposed kinetic model is defined within temperature and substrate concentration ranges of industrial interest (40–60 °C and 3–60 g/L, respectively). Some assumptions were made in order to simplify the model, which is based on a minimum number of parameters. These hypotheses were always specified and assumed only on the basis of convenience and rational consideration. Eventually, the kinetic model was successfully validated by comparison with a vast set of experimental results.     

Dendritic cell activation prevents MHC class II ubiquitination and promotes MHC class II survival regardless of the activation stimulus

The expression of MHC class II (MHC-II) on the surface of antigen-presenting cells, such as dendritic cells (DCs), is tightly regulated during cellular activation. Many cells, including DCs, are activated following stimulation of innate Toll-like receptors (TLRs) by products of microorganisms. In the resting (immature) state, MHC-II is ubiquitinated in immature DCs and is rapidly degraded; however, after activation of these cells with MyD88-dependent TLR ligands, MHC-II ubiquitination is blocked, and MHC-II survival is prolonged. We now show that DC activation using MyD88-dependent TLR ligands, MyD88-independent TLR ligands, and even infection with the intracellular parasite Toxoplasma gondii leads to identical changes in MHC-II expression, ubiquitination, and surface stability, revealing a conserved role for enhanced MHC-II stability after DC activation by different stimuli.     

Molecular dynamics simulation of dextran extension by constant force in single molecule AFM

The extension of 1-6 polysaccharides has been studied in a series of recent single molecule AFM experiments. For dextran, a key finding was the existence of a plateau in the force-extension curve at forces between 700 and 1000 pN. We studied the extension of the dextran 10-mer under constant force using atomistic simulation with various force fields. All the force fields reproduce the experimental plateau on the force-extension curve. With AMBER94 and AMBER-GLYCAM04 force fields the plateau can be explained by a transition of the glucopyranose rings in the dextran monomers from the chair ((4)C(1)) to the inverted chair ((1)C(4)) conformation while other processes occur at smaller (rotation around C5-C6 bond) or higher (chairs to boat transitions) forces. The CHARMM force field provides a different picture which associates the occurrence of the plateau to chair-boat transitions of the glucopyranose rings.     

A new and efficient entry to D-xylo-hexos-4-ulose and some derivatives thereof through epoxidation of the 3,4-hexeno derivative of diacetone-D-glucose

A new preparation of D-xylo-hexos-4-ulose (1) and of its 3-m-chlorobenzoate (2) has been devised using the epoxidation of 3-deoxy-1,2:5,6-di-O-isopropylidene-D-erythro-hex-3-enofuranose (6) as the key step. The epoxidation of 6 in CH2Cl2 furnished with high yield 1,2:5,6-di-O-isopropylidene-3-O-m-chlorobenzoyl-4-C-hydroxy-D-xylo-hexos-4-ulo-1,4-furanose as a mixture of C-4 hemiacetal anomers (7a,b), which, on acid hydrolysis, gave a tautomeric mixture of 3-O-m-chlorobenzoyl-D-xylo-hexos-4-ulose (2) with an overall 60% yield from 6. The formation of 4-C-methoxy-diacetone-D-glucose derivatives (11a,b) through epoxidation-methanolysis of 6, took place with reduced yield because of the competition between m-chlorobenzoic acid (MCBA) and methanol to the opening by attack at C-4 of the intermediate epoxide and the formation of acyclic products arising from the alternative nucleophilic attack at C-1. Acid hydrolysis of derivatives 11 gave D-xylo-hexos-4-ulose (1) with a 35% overall yield from 6. NMR analysis showed that 2 is composed, in CD3CN, mainly by a 7:3 mixture of 4-keto-alpha- and beta-pyranose forms, while 1, in D2O, is present as a more complex mixture constituted mainly by 4-keto-alpha- and beta-pyranoses and their respective hydrates in a 17:15:34:34 ratio.     

Synthesis of the Glc3Man N-glycan tetrasaccharide by iterative allyl IAD

The synthesis of the tetrasaccharide alpha-D-Glcp-(1-->2)-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->3)-alpha-D-Manp-OMe, corresponding to the terminal tetrasaccharide portion of the glucose terminated arm of the N-glycan tetradecasaccharide, was achieved with complete stereocontrol by the use of iterative allyl protecting group mediated intramolecular aglycon delivery (allyl IAD) demonstrating the utility of intramolecular glycosylation for the stereocontrolled construction of multiple glycosidic linkages during the synthesis of an oligosaccharide.