An Intact Kidney Slice Model to Investigate Vasa Recta Properties and Function in situ

Background: Medullary blood flow is via vasa recta capillaries, which possess contractile pericytes. In vitro studies using isolated descending vasa recta show that pericytes can constrict/dilate descending vasa recta when vasoactive substances are present. We describe a live kidney slice model in which pericyte-mediated vasa recta constriction/dilation can be visualized in situ. Methods: Confocal microscopy was used to image calcein, propidium iodide and Hoechst labelling in ‘live’ kidney slices, to determine tubular and vascular cell viability and morphology. DIC video-imaging of live kidney slices was employed to investigate pericyte-mediated real-time changes in vasa recta diameter. Results: Pericytes were identified on vasa recta and their morphology and density were characterized in the medulla. Pericyte-mediated changes in vasa recta diameter (10–30%) were evoked in response to bath application of vasoactive agents (norepinephrine, endothelin-1, angiotensin-II and prostaglandin E2) or by manipulating endogenous vasoactive signalling pathways (using tyramine, L-NAME, a cyclo-oxygenase (COX-1) inhibitor indomethacin, and ATP release). Conclusions: The live kidney slice model is a valid complementary technique for investigating vasa recta function in situ and the role of pericytes as regulators of vasa recta diameter. This technique may also be useful in exploring the role of tubulovascular crosstalk in regulation of medullary blood flow

Microstructural evolution of 3YSZ flash sintered with current ramp control

Ceramics sintered by Flash Sintering (FS), sometimes have heterogeneity in their microstructure. Among the possible causes of this problem, the formation of hotspots is probably the principal issue observed in flash sintering. The hotspots are formed due to the heterogeneity of the resistance of current passing in the green sample. In this way, in the flash phenomenon, the current finds preferential paths, carrying on non-uniform thermal runaway. In this work, we observed that one way of reversing this problem was gradually increasing the electric current density at FS. For this, 3YSZ was shaped in cylindrical form (5 mm height and 6 mm diameter) and flash sintered, at a tubular setup proposed before1, under the application of an AC electric field of 120 V/cm (RMS basis) applied from the beginning of the furnace heating. Three different electric current density ramps were studied: 0.012, 0.024 and 0.048 A.s-1, named as Z1, Z2 and Z3 respectively, until they reached the maximum value of 100 mA.mm-2 (the moment the power supply was turned off). For comparison purposes, conventional FS (Z0) was performed using the same electrical parameters. The electric source, in this case, remained on after reaching 100 mA.mm-2 for 142 s (time calculated to reach the same total energy supplied by the electrical source of samples Z1). After sintering, the apparent densities of the samples were measured according to the Archimedes principle. For analysis of the microstructure, the samples were cut radially and three regions of each sample were observed in SEM: center, right and left surfaces. The grain size distribution was made for each region using ImageJ software. The apparent density of samples sintered by FS was 94 % (Z0) and samples with electrical current ramp were 93 %, 92 % and 87 % for Z1, Z2 and Z3, respectively. The apparent density is proportional to the total energy supplied to the sample (energy provided by the power supply and thermal energy provided by the furnace). Thus, the density of Z0 was expected to be close to the density of Z1. As samples Z2 and Z3 had more abrupt ramps, the energy supplied was lower, which resulted in lower apparent density. The grain size distribution indicates that the mean grain size between the three different regions did not present statistically significant differences (ANOVA test) for the same sample. Please click Additional Files below to see the full abstract

Time-domain nuclear magnetic resonance (TD-NMR) and chemometrics for determination of fat content in commercial products of milk powder.

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Phase evolution during Conventional and Flash Sintering of hydroxyapatite-zirconia composite using in-situ synchrotron x-ray diffraction

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123I-Interleukin-2 scintigraphy for the in vivo assessment of intestinal mononuclear cell infiltration in Chron's disease

Activated mononuclear cells expressing interleukin-2 (IL2) receptors (IL2-Rs) heavily infiltrate the Crohn’s disease (CD) gut wall. A new technique for the in vivo detection of tissue infiltrating IL2-R positive (IL2R1ve) cells was developed based on 123I-IL2 scintigraphy. The aim of this study was to investigate whether 123I-IL2 accumulates in the CD gut wall in different phases of the disease and to evaluate the specificity of 123I-IL2 binding to activated IL2R1ve cells infiltrating the gut wall. Methods: Fifteen patients with ileal CD (10 active and 5 inactive) and 10 healthy volunteers were studied by 123I-IL2 scintigraphy. Six patients with active CD were studied before and after 12 wk of steroid treatment. After scintigraphy, patients were followed up for 29–54 mo. Ex vivo autoradiography was performed to determine specificity of 125IIL2 binding to IL2R1ve cells. For bowel scintigraphy, 123I-IL2 (75 MBq) was injected intravenously and g camera images were acquired after 1 h. Bowel radioactivity was quantified in 64 regions of interest (ROIs). Results: Autoradiography showed specific binding of 125I-IL2 to IL2R1ve mononuclear cells infiltrating the CD gut wall. Intestinal 123I-IL2 uptake assessed by the number of positive ROIs was higher in patients with active or inactive CD than in healthy volunteers (P , 0.0001 andP 5 0.03, respectively) and positively correlated with the CD activity index (P 5 0.01). 123I-IL2 intestinal uptake significantly decreased in patients with CD in steroid-induced remission (P 5 0.03). A significant correlation was observed between the number of positive ROIs and time to disease relapse. Conclusion: 123I-IL2 accumulates in the diseased CD gut wall by specific binding to IL2R1ve cells, infiltrating the involved tissues. 123I-IL2 scintigraphy may be an objective tool for the in vivo assessment of intestinal activated mononuclear cell infiltration

Interleukin-21 sustains inflammatory signals that contribute to sporadic colon tumorigenesis

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.This work received support from the “Fondazione Umberto di Mario ONLUS”, Rome, and AIRC (MFAG-12108 to CS and IG-13049 to GM)

Brazilian Canephora coffee evaluation using NIR spectroscopy and discriminant chemometric techniques.

High-quality Brazilian Canephora coffees are rising to the level of specialty coffees in the face of a new industry perception. In this framework, spectra from 527 coffees were analyzed in the near-infrared (NIR) region. Prin- cipal component analysis distinguished Brazilian Canephora producing states, botanical varieties, low and high- quality Canephora, Canephora and Arabica, and Canephora with geographical indication (GI) from those without GI. Also, Canephora coffee cultivars from Western Brazilian Amazon were distinguished. Three multi-class PLS- DA (traditional, hard, and soft versions) were compared to discriminate 5 classes: Robusta Amaz?onico from traditional (1) and indigenous (2) producers of Rond?onia, Conilon from Espírito Santo (3), Conilon from Bahia (4), and specialty Arabica (5). Binary PLS-DA discriminated GI Canephora and non-GI Canephora with 100% sensitivity and specificity. Carbohydrates, chlorogenic acids, lipids, caffeine, and proteins were dominant ab- sorption bands in coffee classifications. The proposed method is objective, simple, fast, and could be used in the routine analysis of coffee to verify claims of identity, variety, and origin

Interleukin-21 sustains inflammatory signals that contribute to sporadic colon tumorigenesis

Interleukin (IL)-21 triggers inflammatory signals that contribute to the growth of neoplastic cells in mouse models of colitis-associated colorectal cancer (CRC). Because most CRCs are sporadic and arise in the absence of overt inflammation we have investigated the role of IL-21 in these tumors in mouse and man. IL-21 was highly expressed in human sporadic CRC and produced mostly by IFN-γ-expressing T-bet/RORγt double-positive CD3+CD8- cells. Stimulation of human CRC cell lines with IL-21 did not directly activate the oncogenic transcription factors STAT3 and NF-kB and did not affect CRC cell proliferation and survival. In contrast, IL-21 modulated the production of protumorigenic factors by human tumor infiltrating T cells. IL-21 was upregulated in the neoplastic areas, as compared with non-tumor mucosa, of Apc(min/+) mice, and genetic ablation of IL-21 in such mice resulted in a marked decrease of both tumor incidence and size. IL-21 deficiency was associated with reduced STAT3/NF-kB activation in both immune cells and neoplastic cells, diminished synthesis of protumorigenic cytokines (that is, IL-17A, IL-22, TNF-α and IL-6), downregulation of COX-2/PGE2 pathway and decreased angiogenesis in the lesions of Apc(min/+) mice. Altogether, data suggest that IL-21 promotes a protumorigenic inflammatory circuit that ultimately sustains the development of sporadic CRC

Frataxin participates to the hypoxia-induced response in tumors

Defective expression of frataxin is responsible for the degenerative disease Friedreich's ataxia. Frataxin is a protein required for cell survival since complete knockout is lethal. Frataxin protects tumor cells against oxidative stress and apoptosis but also acts as a tumor suppressor. The molecular bases of this apparent paradox are missing. We therefore sought to investigate the pathways through which frataxin enhances stress resistance in tumor cells. We found that frataxin expression is upregulated in several tumor cell lines in response to hypoxic stress, a condition often associated with tumor progression. Moreover, frataxin upregulation in response to hypoxia is dependent on hypoxia-inducible factors expression and modulates the activation of the tumor-suppressor p53. Importantly, we show for the first time that frataxin is in fact increased in human tumors in vivo. These results show that frataxin participates to the hypoxia-induced stress response in tumors, thus implying that modulation of its expression could have a critical role in tumor cell survival and/or progression