Regeneration of the node of Ranvier: a light and electron microscope study

Regeneration of the node of Ranvier was investigated in the rat peroneal nerve 10-60 days after nerve crush, by light and electron microscopy. At 10 and 20 days after crush nodes of Ranvier were clearly identifiable by electron microscopy but had a relatively simple structure. At 40 days after crush however nodes were highly differentiated showing specialised features such as paranodal bulbs, nodal constriction of the axon, paranodal Schwann cell mitochondria, nodal Schwann cell microvilli, and nodal gap substance. By light microscopy some nodes were identifiable as early as 20 days after crush. At both 30 and 60 days after crush regenerated internodes were uniformly short (means of 275 micronm and 339 micronm respectively).     

Conformational transition of insulin induced by n-alkyltrimethylammonium bromides in aqueous solution

A surfactant-induced conformational transition of bovine insulin has been detected by difference spectroscopy for a homologous series of n-alkytrimethylammonium bromides, chain length C10-C16 at pH 10.0, 25 degrees C. The transition was followed as a function of surfactant concentration by absorbance measurements at 275 nm and the data were analysed to obtain the Gibbs energy of the transition in water (delta Gw degree) and in a hydrophobic environment (delta Ghc degree) for saturated protein-surfactant complexes. A value of delta Gw degree of -11.8 +/- 1.8 kJ mol-1 was found independent of n-alkyl chain length, which is similar to the value found for the n-alkylsulfate-induced transition in a previous study (-14.6 +/- 3.0 kJ mol-1). The values of delta Ghc degree were in the range approximately -88 to -100 kJ mol-1 for chain lengths from C10 to C16. The values of delta Ghc degree vs. chain length for both the n-alkyltrimethylammonium bromides and the n-alkylsulfates lie on the same curve, demonstrating that delta Ghc degree is independent of the nature of the surfactant head group.     

Muscarinic receptors in rat cortex, hippocampus, hypothalamus and brainstem following transient forebrain ischemia and hemorrhagic shock

[3H]Quinuclidinyl benzilate binding properties of cerebral cortex, hippocampus, hypothalamus and brainstem of rats subjected to transient forebrain ischemia or severe hemorrhagic shock were investigated. Maximal binding capacities (Bmax) were not significantly different from control animals in either model. On the other hand, significant increases in binding affinities at all four brain regions in the ischemia-reperfusion group and at hypothalamic and brainstem membranes in the hemorrhagic shock group were observed. Kd values obtained in cortex and hippocampus of animals in shock were similar to control values. It was concluded that in brain ischemia models, the number of brain muscarinic receptors do not change at early stages, but binding affinities increase most likely due to systemic hypotension rather than reperfusion. The well-developed circle of Willis seems to protect cortical and hippocampal muscarinic receptors from hypoxia-induced changes.     

Delayed engraftment of nonobese diabetic/severe combined immunodeficient mice transplanted with ex vivo-expanded human CD34(+) cord blood cells

The ex vivo expansion of hematopoietic progenitors is a promising approach for accelerating the engraftment of recipients, particularly when cord blood (CB) is used as a source of hematopoietic graft. With the aim of defining the in vivo repopulating properties of ex vivo-expanded CB cells, purified CD34(+) cells were subjected to ex vivo expansion, and equivalent proportions of fresh and ex vivo-expanded samples were transplanted into irradiated nonobese diabetic (NOD)/severe combined immunodeficient (SCID) mice. At periodic intervals after transplantation, femoral bone marrow (BM) samples were obtained from NOD/SCID recipients and the kinetics of engraftment evaluated individually. The transplantation of fresh CD34(+) cells generated a dose-dependent engraftment of recipients, which was evident in all of the posttransplantation times analyzed (15 to 120 days). When compared with fresh CB, samples stimulated for 6 days with interleukin-3 (IL-3)/IL-6/stem cell factor (SCF) contained increased numbers of hematopoietic progenitors (20-fold increase in colony-forming unit granulocyte-macrophage [CFU-GM]). However, a significant impairment in the short-term repopulation of recipients was associated with the transplantation of the ex vivo-expanded versus the fresh CB cells (CD45(+) repopulation in NOD/SCIDs BM: 3. 7% +/- 1.2% v 26.2% +/- 5.9%, respectively, at 20 days posttransplantation; P <.005). An impaired short-term engraftment was also observed in mice transplanted with CB cells incubated with IL-11/SCF/FLT-3 ligand (3.5% +/- 1.7% of CD45(+) cells in femoral BM at 20 days posttransplantation). In contrast to these data, a similar repopulation with the fresh and the ex vivo-expanded cells was observed at later stages posttransplantation. At 120 days, the repopulation of CD45(+) and CD45(+)/CD34(+) cells in the femoral BM of recipients ranged between 67.2% to 81.1% and 8.6% to 12.6%, respectively, and no significant differences of engraftment between recipients transplanted with fresh and the ex vivo-expanded samples were found. The analysis of the engrafted CD45(+) cells showed that both the fresh and the in vitro-incubated samples were capable of lymphomyeloid reconstitution. Our results suggest that although the ex vivo expansion of CB cells preserves the long-term repopulating ability of the sample, an unexpected delay of engraftment is associated with the transplantation of these manipulated cells.     

Mucosally induced systemic T cell unresponsiveness to ovalbumin requires CD40 ligand-CD40 interactions

CD40 ligand (CD40L) gene-disrupted (CD40L-/-) mice were employed to examine the role of costimulatory signals via CD40L-CD40 interactions in mucosally induced tolerance. CD40L-/- and control (CD40L+/+) mice of the same C57BL/6 x 129/J background were immunized orally with 25 mg of OVA before systemic challenge with OVA in CFA. While CD40L+/+ mice showed reductions in Ag-specific T cell responses including delayed-type hypersensitivity (DTH) and proliferative responses, CD40L-/- mice underwent normal T cell responses. Further, cytokine analysis of splenic CD4+ T cells showed that both Th1-type (e.g., IFN-gamma and IL-2) and Th2-type (e.g., IL-4, IL-5, IL-6, and IL-10) responses were maintained in CD40L-/- mice orally immunized with OVA, whereas these cytokine responses in CD40L+/+ mice were significantly reduced. In addition, splenic CD4+ T cells from CD40L-/- mice orally immunized with OVA provided B cell help in Ag-specific Ab-forming cells when the cells were cultured with naive B cells in the presence of Ag and CD40L-transfected cell lines. In contrast, an identical culture condition containing splenic CD4+ T cells from orally tolerized CD40L+/+ mice did not exhibit helper activity. Taken together, these findings indicate that CD40L and CD40 interactions are essential for the induction of systemic T cell unresponsiveness to orally administered Ag.     

Synergy between bio‐based industry and the feed industry through biorefinery

Processing biomass into multi‐functional components can contribute to the increasing demand for raw materials for feed and bio‐based non‐food products. This contribution aims to demonstrate synergy between the bio‐based industry and the feed industry through biorefinery of currently used feed ingredients. Illustrating the biorefinery concept, rapeseed was selected as a low priced feed ingredient based on market prices versus crude protein, crude fat and apparent ileal digestible lysine content. In addition it is already used as an alternative protein source in diets and can be cultivated in European climate zones. Furthermore, inclusion level of rapeseed meal in pig diet is limited because of its nutritionally active factors. A conceptual process was developed to improve rapeseeds nutritional value and producing other bio‐based building blocks simultaneously. Based on the correlation between market prices of feed ingredients and its protein and fat content, the value of refined products was estimated. Finally, a sensitivity analysis, under two profit scenario, shows that the process is economically feasible. This study demonstrates that using biorefinery processes on feed ingredients can improve feed quality. In conjunction, it produces building blocks for a bio‐based industry and creates synergy between bio‐based and feed industry for more efficient use of biomass. © 2015 Society of Chemical Industry