Brain Glucose Transport and Phosphorylation Under Acute Insulin-Induced Hypoglycemia in Mice: An 18F-FDG PET Study.

We addressed the questions of how cerebral glucose transport and phosphorylation change under acute hypoglycemia and what the underlying mechanisms of adaptation are. METHODS: Quantitative (18)F-FDG PET combined with the acquisition of real-time arterial input function was performed on mice. Hypoglycemia was induced and maintained by insulin infusion. PET data were analyzed with the 2-tissue-compartment model for (18)F-FDG, and the results were evaluated with Michaelis-Menten saturation kinetics. RESULTS: Glucose clearance from plasma to brain (K1,glc) and the phosphorylation rate constant increased with decreasing plasma glucose (Gp), in particular at a Gp of less than 2.5 mmol/L. Estimated cerebral glucose extraction ratios taking into account an increased cerebral blood flow (CBF) at a Gp of less than 2 mmol/L were between 0.14 and 0.79. CBF-normalized K1,glc values were in agreement with saturation kinetics. Phosphorylation rate constants indicated intracellular glucose depletion at a Gp of less than 2-3 mmol/L. When brain regions were compared, glucose transport under hypoglycemia was lowest in the hypothalamus. CONCLUSION: Alterations in glucose transport and phosphorylation, as well as intracellular glucose depletion, under acute hypoglycemia can be modeled by saturation kinetics taking into account an increase in CBF. Distinct transport kinetics in the hypothalamus may be involved in its glucose-sensing function.

Rebound and disinvestment effects in oil consumption and supply resulting from an increase in energy efficiency in the Scottish commercial transport sector

In this paper we use an energy-economy-environment computable general equilibrium (CGE) model of the Scottish economy to examine the impacts of an exogenous increase in energy augmenting technological progress in the domestic commercial Transport sector on the supply and use of energy. We focus our analysis on oil, as the main type of energy input used in commercial transport activity. We find that a 5% increase in energy efficiency in the commercial Transport sector leads to rebound effects in the use of oil-based energy commodities in all time periods, in the target sector and at the economy-wide level. However, our results also suggest that such an efficiency improvement may cause a contraction in capacity in the Scottish oil supply sector. This ‘disinvestment effect’ acts as a constraint on the size of rebound effects. However, the magnitude of rebound effects and presence of the disinvestment effect in the simulations conducted here are sensitive to the specification of key elasticities of substitution in the nested production function for the target sector, particularly the substitutability of energy for non-energy intermediate inputs to production.

Association of the Epstein-Barr virus latent membrane protein 1 with lipid rafts is mediated through its N-terminal region.

The latent membrane protein 1 (LMP1) encoded by the Epstein-Barr virus acts like a constitutively activated receptor of the tumor necrosis factor receptor (TNFR) family and is enriched in lipid rafts. We showed that LMP1 is targeted to lipid rafts in transfected HEK 293 cells, and that the endogenous TNFR-associated factor 3 binds LMP1 and is recruited to lipid rafts upon LMP1 expression. An LMP1 mutant lacking the C-terminal 55 amino acids (Cdelta55) behaves like the wild-type (WT) LMP1 with respect to membrane localization. In contrast, a mutant with a deletion of the 25 N-terminal residues (Ndelta25) does not concentrate in lipid rafts but still binds TRAF3, demonstrating that cell localization of LMP1 was not crucial for TRAF3 localization. Moreover, Ndelta25 inhibited WT LMP1-mediated induction of the transcription factors NF-kappaB and AP-1. Morphological data indicate that Ndelta25 hampers WT LMP1 plasma membrane localization, thus blocking LMP1 function.

Photodynamic therapy enhances liposomal doxorubicin distribution in tumors during isolated perfusion of rodent lungs.

BACKGROUND: Photodynamic therapy (PDT) at low drug-light conditions can enhance the transport of intravenously injected macromolecular therapeutics through the tumor vasculature. Here we determined the impact of PDT on the distribution of liposomal doxorubicin (Liporubicin™) administered by isolated lung perfusion (ILP) in sarcomas grown on rodent lungs. METHODS: A syngeneic methylcholanthrene-induced sarcoma cell line was implanted subpleurally in the left lung of Fischer rats. Treatment schemes consisted in ILP alone (400 μg of Liporubicin), low-dose (0.0625 mg/kg Visudyne®, 10 J/cm(2) and 35 mW/cm(2)) and high-dose left lung PDT (0.125 mg/kg Visudyne, 10 J/cm(2) and 35 mW/cm(2)) followed by ILP (400 μg of Liporubicin). The uptake and distribution of Liporubicin in tumor and lung tissues were determined by high-performance liquid chromatography and fluorescence microscopy in each group. RESULTS: Low-dose PDT significantly improved the distribution of Liporubicin in tumors compared to high-dose PDT (p < 0.05) and ILP alone (p < 0.05). However, both PDT pretreatments did not result in a higher overall drug uptake in tumors or a higher tumor-to-lung drug ratio compared to ILP alone. CONCLUSIONS: Intraoperative low-dose Visudyne-mediated PDT enhances liposomal doxorubicin distribution administered by ILP in sarcomas grown on rodent lungs which is predicted to improve tumor control by ILP.

Genetic- or transforming growth factor-beta 1-induced changes in epidermal peroxisome proliferator-activated receptor beta/delta expression dictate wound repair kinetics.

Advances in wound care are of great importance in clinical injury management. In this respect, the nuclear receptor peroxisome proliferator-activated receptor (PPAR)beta/delta occupies a unique position at the intersection of diverse inflammatory or anti-inflammatory signals that influence wound repair. This study shows how changes in PPARbeta/delta expression have a profound effect on wound healing. Using two different in vivo models based on topical application of recombinant transforming growth factor (TGF)-beta1 and ablation of the Smad3 gene, we show that prolonged expression and activity of PPARbeta/delta accelerate wound closure. The results reveal a dual role of TGF-beta1 as a chemoattractant of inflammatory cells and repressor of inflammation-induced PPARbeta/delta expression. Also, they provide insight into the so far reported paradoxical effects of the application of exogenous TGF-beta1 at wound sites.

Sarcopromusca pruna (Diptera: Muscidae) as an egg transport host of Dermatobia hominis (Diptera: Cuterebridae) in the cacau region of Bahia, Brazil

Sarcopromusca pruna appears to be the predominant transport host for Dermatobia hominis eggs among cattle herds in central eastern Bahia, Brazil. In the study area, two seasonal peaks of S. Pruna abundance coincide with those of Dermatobia, from mid July through late September and from mid November until early January, two periods of moderate monthly rainfall between anual extremes. Among more than 26,000 flies examined during the study, 75 (all female S. pruna) bore Dermatobia eggs. Certain aspects of Dermatobia behavior and ovoposition habits in the field are also discussed.

Continuity of set-valued maps revisited in the light of tame geometry

Continuity of set-valued maps is hereby revisited: after recalling some basic concepts of variational analysis and a short description of the State-of-the-Art, we obtain as by-product two Sard type results concerning local minima of scalar and vector valued functions. Our main result though, is inscribed in the framework of tame geometry, stating that a closed-valued semialgebraic set-valued map is almost everywhere continuous (in both topological and measure-theoretic sense). The result –depending on stratification techniques– holds true in a more general setting of o-minimal (or tame) set-valued maps. Some applications are briefly discussed at the end.

Efficient Subtractive Cloning of Genes Activated by Lipopolysaccharide and Interferon γ in Primary-Cultured Cortical Cells of Newborn Mice.

Innate immune responses play a central role in neuroprotection and neurotoxicity during inflammatory processes that are triggered by pathogen-associated molecular pattern-exhibiting agents such as bacterial lipopolysaccharide (LPS) and that are modulated by inflammatory cytokines such as interferon γ (IFNγ). Recent findings describing the unexpected complexity of mammalian genomes and transcriptomes have stimulated further identification of novel transcripts involved in specific physiological and pathological processes, such as the neural innate immune response that alters the expression of many genes. We developed a system for efficient subtractive cloning that employs both sense and antisense cRNA drivers, and coupled it with in-house cDNA microarray analysis. This system enabled effective direct cloning of differentially expressed transcripts, from a small amount (0.5 µg) of total RNA. We applied this system to isolation of genes activated by LPS and IFNγ in primary-cultured cortical cells that were derived from newborn mice, to investigate the mechanisms involved in neuroprotection and neurotoxicity in maternal/perinatal infections that cause various brain injuries including periventricular leukomalacia. A number of genes involved in the immune and inflammatory response were identified, showing that neonatal neuronal/glial cells are highly responsive to LPS and IFNγ. Subsequent RNA blot analysis revealed that the identified genes were activated by LPS and IFNγ in a cooperative or distinctive manner, thereby supporting the notion that these bacterial and cellular inflammatory mediators can affect the brain through direct but complicated pathways. We also identified several novel clones of apparently non-coding RNAs that potentially harbor various regulatory functions. Characterization of the presently identified genes will give insights into mechanisms and interventions not only for perinatal infection-induced brain damage, but also for many other innate immunity-related brain disorders.

Reduced Prostasin (CAP1/PRSS8) Activity Eliminates HAI-1 and HAI-2 Deficiency-Associated Developmental Defects by Preventing Matriptase Activation.

Loss of either hepatocyte growth factor activator inhibitor (HAI)-1 or -2 is associated with embryonic lethality in mice, which can be rescued by the simultaneous inactivation of the membrane-anchored serine protease, matriptase, thereby demonstrating that a matriptase-dependent proteolytic pathway is a critical developmental target for both protease inhibitors. Here, we performed a genetic epistasis analysis to identify additional components of this pathway by generating mice with combined deficiency in either HAI-1 or HAI-2, along with genes encoding developmentally co-expressed candidate matriptase targets, and screening for the rescue of embryonic development. Hypomorphic mutations in Prss8, encoding the GPI-anchored serine protease, prostasin (CAP1, PRSS8), restored placentation and normal development of HAI-1-deficient embryos and prevented early embryonic lethality, mid-gestation lethality due to placental labyrinth failure, and neural tube defects in HAI-2-deficient embryos. Inactivation of genes encoding c-Met, protease-activated receptor-2 (PAR-2), or the epithelial sodium channel (ENaC) alpha subunit all failed to rescue embryonic lethality, suggesting that deregulated matriptase-prostasin activity causes developmental failure independent of aberrant c-Met and PAR-2 signaling or impaired epithelial sodium transport. Furthermore, phenotypic analysis of PAR-1 and matriptase double-deficient embryos suggests that the protease may not be critical for focal proteolytic activation of PAR-2 during neural tube closure. Paradoxically, although matriptase auto-activates and is a well-established upstream epidermal activator of prostasin, biochemical analysis of matriptase- and prostasin-deficient placental tissues revealed a requirement of prostasin for conversion of the matriptase zymogen to active matriptase, whereas prostasin zymogen activation was matriptase-independent.

Quantifying rates of landscape evolution and tectonic processes by thermochronology and numerical modeling of crustal heat transport using PECUBE

PECUBE is a three-dimensional thermal-kinematic code capable of solving the heat production-diffusion-advection equation under a temporally varying surface boundary condition. It was initially developed to assess the effects of time-varying surface topography (relief) on low-temperature thermochronological datasets. Thermochronometric ages are predicted by tracking the time-temperature histories of rock-particles ending up at the surface and by combining these with various age-prediction models. In the decade since its inception, the PECUBE code has been under continuous development as its use became wider and addressed different tectonic-geomorphic problems. This paper describes several major recent improvements in the code, including its integration with an inverse-modeling package based on the Neighborhood Algorithm, the incorporation of fault-controlled kinematics, several different ways to address topographic and drainage change through time, the ability to predict subsurface (tunnel or borehole) data, prediction of detrital thermochronology data and a method to compare these with observations, and the coupling with landscape-evolution (or surface-process) models. Each new development is described together with one or several applications, so that the reader and potential user can clearly assess and make use of the capabilities of PECUBE. We end with describing some developments that are currently underway or should take place in the foreseeable future. (C) 2012 Elsevier B.V. All rights reserved.

Protective role of peroxisome proliferator-activated receptor-β/δ in septic shock.

Rationale: Peroxisome proliferator activated receptor (PPAR)-beta/delta is a transcription factor that belongs to the PPAR nuclear hormone receptor family, but the role of PPAR-beta/delta in sepsis is unknown. Objectives: We investigated the role of PPAR-beta/delta in murine models of LPS-induced organ injury and dysfunction and cecal ligation and puncture (CLP)-induced polymicrobial sepsis. Methods: Wild-type (WT) and PPAR-beta/delta knockout (1(0) mice and C57BL/6 mice were subjected to LPS for 16 hours. C57BL/6 mice received the PPAR-beta/delta agonist GW0742 (0.03 mg/kg intravenously, 1 h after LPS) or GW0742 plus the PPAR-beta/delta antagonist GSK0660 (0.1 mg/kg intravenously, 30 min before LPS). CD-1 mice subjected to CLP received GW0742 or GW0742 plus GSK0660. Measurements and Main Results: In PPAR-beta/delta KO mice, endotoxemia exacerbated organ injury and dysfunction (cardiac, renal, and hepatic) and inflammation (lung) compared with WT mice. In C57BL/6 mice subjected to endotoxemia, GW0742 significantly (1) attenuated organ (cardiac and renal) dysfunction and inflammation (lung); (2) increased the phosphorylation of Akt and glycogen synthase kinase (GSK)-3 beta; (3) attenuated the increase in extracellular signal-regulated kinase (ERK)1/2 and signal transducer and activator of transcription (STAT)-3 phosphorylation; and (4) attenuated the activation of nuclear factor (NF)-kappa B and the expression of inducible nitric oxide synthase (iNOS). In CD-1 mice subjected to CLP, GW0742 improved 10-day survival. All the observed beneficial effects of GW0742 were attenuated by the PPAR-beta/delta antagonist GSK0660. Conclusions: PPAR-beta/delta protects against multiple organ injury and dysfunction, and inflammation caused by endotoxic shock and improves survival in polymicrobial sepsis by a mechanism that may involve activation of Akt and inhibition of GSK-3 beta and NF-kappa B.

Contribution of TIR domain-containing adapter inducing IFN-beta-mediated IL-18 release to LPS-induced liver injury in mice.

BACKGROUND/AIMS: After treatment with heat-killed Propionibacterium acnes mice show dense hepatic granuloma formation. Such mice develop liver injury in an interleukin (IL)-18-dependent manner after challenge with a sublethal dose LPS. As previously shown, LPS-stimulated Kupffer cells secrete IL-18 depending on caspase-1 and Toll-like receptor (TLR)-4 but independently of its signal adaptor myeloid differentiation factor 88 (MyD88), suggesting importance of another signal adaptor TIR domain-containing adapter inducing IFN-beta (TRIF). Nalp3 inflammasome reportedly controls caspase-1 activation. Here we investigated the roles of MyD88 and TRIF in P. acnes-induced hepatic granuloma formation and LPS-induced caspase-1 activation for IL-18 release. METHODS: Mice were sequentially treated with P. acnes and LPS, and their serum IL-18 levels and liver injuries were determined by ELISA and ALT/AST measurement, respectively. Active caspase-1 in LPS-stimulated Kupffer cells was determined by Western blotting. RESULTS: Macrophage-ablated mice lacked P. acnes-induced hepatic granuloma formation and LPS-induced serum IL-18 elevation and liver injury. Myd88(-/-) Kupffer cells, but not Trif(-/-) cells, exhibited normal caspase-1 activation upon TLR4 engagement in vitro. Myd88(-/-) mice failed to develop hepatic granulomas after P. acnes treatment and liver injury induced by LPS challenge. In contrast, Trif(-/-) mice normally formed the hepatic granulomas, but could not release IL-18 or develop the liver injury. Nalp3(-/-) mice showed the same phenotypes of Trif(-/-) mice. CONCLUSIONS: Propionibacterium acnes treatment MyD88-dependently induced hepatic granuloma formation. Subsequent LPS TRIF-dependently activated caspase-1 via Nalp3 inflammasome and induced IL-18 release, eventually leading to the liver injury.

Normal kinetics of intestinal glucose absorption in the absence of GLUT2: evidence for a transport pathway requiring glucose phosphorylation and transfer into the endoplasmic reticulum.

Glucose is absorbed through the intestine by a transepithelial transport system initiated at the apical membrane by the cotransporter SGLT-1; intracellular glucose is then assumed to diffuse across the basolateral membrane through GLUT2. Here, we evaluated the impact of GLUT2 gene inactivation on this transepithelial transport process. We report that the kinetics of transepithelial glucose transport, as assessed in oral glucose tolerance tests, was identical in the presence or absence of GLUT2; that the transport was transcellular because it could be inhibited by the SGLT-1 inhibitor phlorizin, and that it could not be explained by overexpression of another known glucose transporter. By using an isolated intestine perfusion system, we demonstrated that the rate of transepithelial transport was similar in control and GLUT2(-/-) intestine and that it was increased to the same extent by cAMP in both situations. However, in the absence, but not in the presence, of GLUT2, the transport was inhibited dose-dependently by the glucose-6-phosphate translocase inhibitor S4048. Furthermore, whereas transport of [(14)C]glucose proceeded with the same kinetics in control and GLUT2(-/-) intestine, [(14)C]3-O-methylglucose was transported in intestine of control but not of mutant mice. Together our data demonstrate the existence of a transepithelial glucose transport system in GLUT2(-/-) intestine that requires glucose phosphorylation and transfer of glucose-6-phosphate into the endoplasmic reticulum. Glucose may then be released out of the cells by a membrane traffic-based pathway similar to the one we previously described in GLUT2-null hepatocytes.