Effects of streptozotocin-induced diabetes and elevation of plasma FFA on ceramide metabolism in rat skeletal muscle.

Ceramide is likely to mediate in induction of insulin resistance. The aim of the present study was to examine the effect of streptozotocin-diabetes and treatment with heparin on ceramide metabolism in skeletal muscles. The experiments were performed on Wistar rats divided into three groups: 1) control, 2) treated with streptozotocin, and 3) treated with heparin.

Plasma sphingosine-1-phosphate concentration is reduced in patients with myocardial infarction.

Background: The sphingolipid sphingosine-1-phosphate (S1P) plays an important role in protecting the heart against ischemia-reperfusion injury. S1P is normally present in human plasma. However, there are no data available on the effect of myocardial infarction on the plasma concentrations of S1P and related sphingolipids.

Two compensatory pathways maintain long-term stability and diversity in CD8 T cell memory repertoires.

The time-dependent changes of human memory T cell repertoires are still poorly understood. We define a T cell memory repertoire as the pool of clonotypic lineages participating in a recall response to the influenza M1(58-66) epitope. In HLA-A2 individuals, this response predominantly uses BV19 chains with Arg-Ser (RS) in the CDR3 loop.

The transcription factor RFX protects MHC class II genes against epigenetic silencing by DNA methylation.

Classical and nonclassical MHC class II (MHCII) genes are coregulated by the transcription factor RFX (regulatory factor X) and the transcriptional coactivator CIITA. RFX coordinates the assembly of a multiprotein "enhanceosome" complex on MHCII promoters. This enhanceosome serves as a docking site for the binding of CIITA.

Peroxisome proliferator-activated receptor alpha activation induces unfavourable changes in fatty acid composition of myocardial phospholipids.

Peroxisome proliferator-activated receptor alpha (PPARalpha) plays a crucial role in the transcriptional regulation of myocardial lipid metabolism. In vitro studies on isolated cardiomyocytes showed that PPARalpha activation induces expression of numerous genes involved in virtually all steps of fatty acid catabolism. However, there is very few data on the effect of PPARalpha activation on the content and composition of myocardial lipids in vivo.

Myocardium of type 2 diabetic and obese patients is characterized by alterations in sphingolipid metabolic enzymes but not by accumulation of ceramide.

Data from animal experiments strongly suggest that ceramide is an important mediator of lipotoxicity in the heart and that accumulation of ceramide contributes to cardiomyocyte apoptosis associated with type 2 diabetes and obesity. However, it remains unknown whether a similar relationship is present also in the human heart. Therefore, we aimed to examine whether myocardial apoptosis in obese and type 2 diabetic patients is associated with elevated ceramide level.

Differential effects of chronic, in vivo, PPAR's stimulation on the myocardial subcellular redistribution of FAT/CD36 and FABPpm.

This study reveals that the activation of either PPARalpha (WY 14643) or PPARbeta (GW0742) each induce the translocation of FAT/CD36 from an intracellular pool(s) to the plasma membrane, while PPARbeta also induces the subcellular redistribution of FABPpm(Got2) to the plasma membrane. In contrast, activation of PPARgamma failed to induce the subcellular redistribution of FAT/CD36 and FABPpm. These PPARalpha-, and PPARbeta-induced changes in the plasmalemmal content of these fatty acid transporters were associated with the concurrent upregulation of fatty acid triacylglycerol esterification (PPARbeta) and oxidation (PPARalpha and PPARbeta).

A clonotype nomenclature for T cell receptors.

T cell receptor (TCR) nucleotide sequences are often generated during analyses of T cell responses to pathogens or autoantigens. The most important region of the TCR is the third complementarity-determining region (CDR3) whose nucleotide sequence is unique to each T cell clone. The CDR3 interacts with the peptide and thus is important for recognizing pathogen or autoantigen epitopes.

Differential effects of in vivo PPAR alpha and gamma activation on fatty acid transport proteins expression and lipid content in rat liver.

Peroxisome proliferator-activated receptors (PPAR;s) serve as lipid sensors and when activated modify gene expression of proteins highly involved in the regulation of fatty acid metabolism. Recently, the accumulation of lipids in liver was shown to be depended on the excessive protein-mediated transmembrane transport of long chain fatty acids (LCFAs). The aim of the present study was to determine the in vivo effects of PPARalpha and gamma activation at two levels: 1) on the expression of fatty acid transporters, 2) on the content and fatty acids saturation status of lipids in rats liver.

An accessible micro-capillary electrophoresis device using surface-tension-driven flow.

We present a rapidly fabricated micro-capillary electrophoresis chip that utilizes surface-tension-driven flow for sample injection and extraction of DNA. Surface-tension-driven flow (i.e.

Semiphysiologically based pharmacokinetic models for the inhibition of midazolam clearance by diltiazem and its major metabolite.

Prediction of the extent and time course of drug-drug interactions (DDIs) between the mechanism-based inhibitor diltiazem (DTZ) and the CYP3A4 substrate midazolam (MDZ) is confounded by time- and concentration-dependent clearance of the inhibitor. Semiphysiologically based pharmacokinetic (PBPK) models were developed for DTZ and MDZ with the major metabolite of DTZ, N-desmethyldiltiazem (nd-DTZ), incorporated in the DTZ model. Enzyme kinetic parameters (k(inact) and K(I)) for DTZ and nd-DTZ were estimated in vitro and used to model the time course of changes in the amount of CYP3A4 in the liver and gut wall, which in turn, determined the nonlinear elimination of MDZ and DTZ, and the corresponding DDI.

Estrogen increases survival in an orthotopic model of glioblastoma.

Despite the male preponderance for developing glial tumors and a body of published literature that suggests a female gender advantage for long term survival in both human and animal studies, there have been relatively few rigorous investigations into the hormonal effects on glial tumor growth. In a previous study, we concluded that estrogen played a major role in the female survival bias seen in an intracerebral nude rat model of glioblastoma multiforme. Here we explore the potential therapeutic effect of exogenous estradiol delivery in nude rats with orthotopic glioblastoma tumors and examine the mechanism of action of estradiol on reducing tumor growth in this animal model.

Chronic, in vivo, PPARalpha activation prevents lipid overload in rat liver induced by high fat feeding.

Purpose: Peroxisome proliferator-activated receptors (PPAR's) are lipid sensors and when activated they modify gene expression of proteins regulating fatty acid (FA) metabolism in liver cells. The aim of the present study was to examine the in vivo effects of PPAR alpha and gamma activation combined with high fat diet (HFD) feeding on the lipid content and FA profile in the liver.

Material/methods: We assessed whether in vivo activation of PPARs (alpha or gamma) affects lipid accumulation in the liver induced by HFD feeding.

Genetically encoded sensors to elucidate spatial distribution of cellular zinc.

Transition metals are essential enzyme cofactors that are required for a wide range of cellular processes. Paradoxically, whereas metal ions are essential for numerous cellular processes, they are also toxic. Therefore cells must tightly regulate metal accumulation, transport, distribution, and export.

Short-term effects of electrically induced tachycardia on antioxidant defenses in the normal and hypertrophied rat left ventricle.

Increased oxidative stress resulting from enhanced production of reactive oxygen species and/or inadequate mechanisms of antioxidant defenses has been recognized as an important factor contributing to the initiation and progression of cardiac dysfunction under a wide variety of pathophysiological conditions. The main objective of this study was to examine the effect of electrically induced tachycardia on oxidative stress and the capacity of antioxidant defenses in the normal and hypertrophied left ventricle (LV) in the rat. Left ventricular hypertrophy (LVH) was produced by banding the descending abdominal aorta.

n-3 fatty acids and rosiglitazone improve insulin sensitivity through additive stimulatory effects on muscle glycogen synthesis in mice fed a high-fat diet.

Aims/hypothesis: Fatty acids of marine origin, i.e. docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) act as hypolipidaemics, but they do not improve glycaemic control in obese and diabetic patients.

IL-6 deficiency increases fatty acid transporters and intramuscular lipid content in red but not white skeletal muscle.

IL-6 is a biologically active substance which appears to be involved in regulating skeletal muscle lipid oxidation. Ablation of IL-6 (IL-6(-/-)) may therefore be expected to increase intracellular lipid accumulation, possibly via a concurrent increase in fatty acid transporters such as FAT/CD36 and FABPpm. This however may only occur in oxidative muscles which utilize fatty acids at a greater rate than glycolytic muscles.

Faciogenital dysplasia protein (FGD1) regulates export of cargo proteins from the golgi complex via Cdc42 activation.

Mutations in the FGD1 gene are responsible for the X-linked disorder known as faciogenital dysplasia (FGDY). FGD1 encodes a guanine nucleotide exchange factor that specifically activates the GTPase Cdc42. In turn, Cdc42 is an important regulator of membrane trafficking, although little is known about FGD1 involvement in this process.

The complex relationship between BRCA1 and ERalpha in hereditary breast cancer.

Breast cancer 1 (BRCA1) was initially identified as one of the genes conferring genetic predisposition to both breast and ovarian cancer. One of the interesting aspects of BRCA1-linked cancers is the observed specificity for estrogen-responsive tissues such as breast and ovary. Recent advances in our understanding of BRCA1-linked breast cancers have revealed a complex relationship between BRCA1 and estrogen receptor alpha (ERalpha) signaling.

Interindividual variability in the response to oral antiplatelet drugs: a position paper of the Working Group on antiplatelet drugs resistance appointed by the Section of Cardiovascular Interventions of the Polish Cardiac Society, endorsed by the Working Group on Thrombosis of the European Society of Cardiology.

Oral antiplatelet drugs are a cornerstone of modern pharmacotherapy in cardiovascular atherothrombotic diseases. The efficacy of acetylsalicylic acid (ASA, aspirin) and clopidogrel in decreasing the risk of adverse events in coronary heart disease patients has been well established in the past 20 years. Despite chronic oral antiplatelet therapy, a number of atherothombotic events continue to occur.

Confocal laser Raman microspectroscopy of biomineralization foci in UMR 106 osteoblastic cultures reveals temporally synchronized protein changes preceding and accompanying mineral crystal deposition.

Mineralization in UMR 106-01 osteoblastic cultures occurs within extracellular biomineralization foci (BMF) within 12 h after addition of beta-glycerol phosphate to cells at 64 h after plating. BMF are identified by their enrichment with an 85-kDa glycoprotein reactive with Maackia amurensis lectin. Laser Raman microspectroscopic scans were made on individual BMF at times preceding (64-76 h) and following the appearance of mineral crystals (76-88 h).

HLA-DM mediates epitope selection by a "compare-exchange" mechanism when a potential peptide pool is available.

Background: HLA-DM (DM) mediates exchange of peptides bound to MHC class II (MHCII) during the epitope selection process. Although DM has been shown to have two activities, peptide release and MHC class II refolding, a clear characterization of the mechanism by which DM facilitates peptide exchange has remained elusive.

Methodology/principal Findings: We have previously demonstrated that peptide binding to and dissociation from MHCII in the absence of DM are cooperative processes, likely related to conformational changes in the peptide-MHCII complex.

Impaired survival of peripheral T cells, disrupted NK/NKT cell development, and liver failure in mice lacking Gimap5.

The loss of Gimap5 (GTPase of the immune-associated protein 5) gene function is the underlying cause of lymphopenia and autoimmune diabetes in the BioBreeding (BB) rat. The in vivo function of murine gimap5 is largely unknown. We show that selective gene ablation of the mouse gimap5 gene impairs the final intrathymic maturation of CD8 and CD4 T cells and compromises the survival of postthymic CD4 and CD8 cells, replicating findings in the BB rat model.

Isolation of calcospherulites from the mineralization front of bone.

Calcium-containing spherical bodies (calcospherulites) exist along the mineralization front of bone and are thought to play a role in bone formation. Existing methods to isolate calcospherulites involve harsh treatments that remove much of their organic matter. This study sought to isolate them using a less destructive approach to better preserve their organic components.

Potential role of proprotein convertase SKI-1 in the mineralization of primary bone.

The biochemical mechanism controlling nucleation of mineral crystals in developing bone, along with the growth and propagation of these crystals once formed, remains poorly understood. To define the nucleation mechanism, a proteomics analysis was begun on isolated biomineralization foci (BMF), sites of initial crystal nucleation in osteoblastic cell cultures and in primary bone. Comparative analyses of the protein profile for mineralized BMF with that for total osteoblast cultures revealed the latter were enriched in several proteins including BAG-75 and BSP, as well as fragments of each.