Immunolocalization of GLUTX1 in the testis and to specific brain areas and vasopressin-containing neurons.

GLUTX1 or GLUT8 is a newly characterized glucose transporter isoform that is expressed at high levels in the testis and brain and at lower levels in several other tissues. Its expression was mapped in the testis and brain by using specific antibodies. In the testis, immunoreactivity was expressed in differentiating spermatocytes of type 1 stage but undetectable in mature spermatozoa. In the brain, GLUTX1 distribution was selective and localized to a variety of structures, mainly archi- and paleocortex. It was found in hippocampal and dentate gyrus neurons as well as amygdala and primary olfactory cortex. In these neurons, its location was close to the plasma membrane of cell bodies and sometimes in proximal dendrites. High GLUTX1 levels were detected in the hypothalamus, supraoptic nucleus, median eminence, and the posterior pituitary. Neurons of these areas synthesize and secrete vasopressin and oxytocin. As shown by double immunofluorescence microscopy and immunogold labeling, GLUTX1 was expressed only in vasopressin neurons. By immunogold labeling of ultrathin cryosections microscopy, GLUTX1 was identified in dense core vesicles of synaptic nerve endings of the supraoptic nucleus and secretory granules of the vasopressin positive neurons. This localization suggests an involvement of GLUTX1 both in specific neuron function and endocrine mechanisms.

Misconceptions about fructose-containing sugars and their role in the obesity epidemic.

A causal role of fructose intake in the aetiology of the global obesity epidemic has been proposed in recent years. This proposition, however, rests on controversial interpretations of two distinct lines of research. On one hand, in mechanistic intervention studies, detrimental metabolic effects have been observed after excessive isolated fructose intakes in animals and human subjects. On the other hand, food disappearance data indicate that fructose consumption from added sugars has increased over the past decades and paralleled the increase in obesity. Both lines of research are presently insufficient to demonstrate a causal role of fructose in metabolic diseases, however. Most mechanistic intervention studies were performed on subjects fed large amounts of pure fructose, while fructose is ordinarily ingested together with glucose. The use of food disappearance data does not accurately reflect food consumption, and hence cannot be used as evidence of a causal link between fructose intake and obesity. Based on a thorough review of the literature, we demonstrate that fructose, as commonly consumed in mixed carbohydrate sources, does not exert specific metabolic effects that can account for an increase in body weight. Consequently, public health recommendations and policies aiming at reducing fructose consumption only, without additional diet and lifestyle targets, would be disputable and impractical. Although the available evidence indicates that the consumption of sugar-sweetened beverages is associated with body-weight gain, and it may be that fructose is among the main constituents of these beverages, energy overconsumption is much more important to consider in terms of the obesity epidemic.

Effect of atazanavir versus other protease inhibitor-containing antiretroviral therapy on endothelial function in HIV-infected persons: randomised controlled trial.

OBJECTIVE: Impaired endothelial function was demonstrated in HIV-infected persons on protease inhibitor (PI)-containing antiretroviral therapy, probably due to altered lipid metabolism. Atazanavir is a PI causing less atherogenic lipoprotein changes. This study determined whether endothelial function improves after switching from other PI to atazanavir. DESIGN: Randomised, observer-blind, treatment-controlled trial. SETTING: Three university-based outpatient clinics. PATIENTS: 39 HIV-infected persons with suppressed viral replication on PI-containing regimens and fasting low-density lipoprotein (LDL)-cholesterol greater than 3 mmol/l. INTERVENTION: Patients were randomly assigned to continue the current PI or change to unboosted atazanavir. MAIN OUTCOME MEASURES: Endpoints at week 24 were endothelial function assessed by flow-mediated dilation (FMD) of the brachial artery, lipid profiles and serum inflammation and oxidative stress parameters. RESULTS: Baseline characteristics and mean FMD values of the two treatment groups were comparable (3.9% (SD 1.8) on atazanavir versus 4.0% (SD 1.5) in controls). After 24 weeks' treatment, FMD decreased to 3.3% (SD 1.4) and 3.4% (SD 1.7), respectively (all p = ns). Total cholesterol improved in both groups (p<0.0001 and p = 0.01, respectively) but changes were more pronounced on atazanavir (p = 0.05, changes between groups). High-density lipoprotein and triglyceride levels improved on atazanavir (p = 0.03 and p = 0.003, respectively) but not in controls. Serum inflammatory and oxidative stress parameters did not change; oxidised LDL improved significantly in the atazanavir group. CONCLUSIONS: The switch from another PI to atazanavir in treatment-experienced patients did not result in improvement of endothelial function despite significantly improved serum lipids. Atherogenic lipid profiles and direct effects of antiretroviral drugs on the endothelium may affect vascular function. Trial registration number: NCT00447070.

An SH2 domain-containing 5' inositolphosphatase inhibits insulin-induced GLUT4 translocation and growth factor-induced actin filament rearrangement.

Tyrosine kinase receptors lead to rapid activation of phosphatidylinositol 3-kinase (PI3 kinase) and the subsequent formation of phosphatidylinositides (PtdIns) 3,4-P2 and PtdIns 3,4, 5-P3, which are thought to be involved in signaling for glucose transporter GLUT4 translocation, cytoskeletal rearrangement, and DNA synthesis. However, the specific role of each of these PtdIns in insulin and growth factor signaling is still mainly unknown. Therefore, we assessed, in the current study, the effect of SH2-containing inositol phosphatase (SHIP) expression on these biological effects. SHIP is a 5' phosphatase that decreases the intracellular levels of PtdIns 3,4,5-P3. Expression of SHIP after nuclear microinjection in 3T3-L1 adipocytes inhibited insulin-induced GLUT4 translocation by 100 +/- 21% (mean +/- the standard error) at submaximal (3 ng/ml) and 64 +/- 5% at maximal (10 ng/ml) insulin concentrations (P < 0.05 and P < 0.001, respectively). A catalytically inactive mutant of SHIP had no effect on insulin-induced GLUT4 translocation. Furthermore, SHIP also abolished GLUT4 translocation induced by a membrane-targeted catalytic subunit of PI3 kinase. In addition, insulin-, insulin-like growth factor I (IGF-I)-, and platelet-derived growth factor-induced cytoskeletal rearrangement, i.e., membrane ruffling, was significantly inhibited (78 +/- 10, 64 +/- 3, and 62 +/- 5%, respectively; P < 0.05 for all) in 3T3-L1 adipocytes. In a rat fibroblast cell line overexpressing the human insulin receptor (HIRc-B), SHIP inhibited membrane ruffling induced by insulin and IGF-I by 76 +/- 3% (P < 0.001) and 68 +/- 5% (P < 0.005), respectively. However, growth factor-induced stress fiber breakdown was not affected by SHIP expression. Finally, SHIP decreased significantly growth factor-induced mitogen-activated protein kinase activation and DNA synthesis. Expression of the catalytically inactive mutant had no effect on these cellular responses. In summary, our results show that expression of SHIP inhibits insulin-induced GLUT4 translocation, growth factor-induced membrane ruffling, and DNA synthesis, indicating that PtdIns 3,4,5-P3 is the key phospholipid product mediating these biological actions.

Antibacterial burst-release from minimal Ag-containing plasma polymer coatings.

Biomaterials releasing silver (Ag) are of interest because of their ability to inhibit pathogenic bacteria including antibiotic-resistant strains. In order to investigate the potential of nanometre-thick Ag polymer (Ag/amino-hydrocarbon) nanocomposite plasma coatings, we studied a comprehensive range of factors such as the plasma deposition process and Ag cation release as well as the antibacterial and cytocompatible properties. The nanocomposite coatings released most bound Ag within the first day of immersion in water yielding an antibacterial burst. The release kinetics correlated with the inhibitory effects on the pathogens Pseudomonas aeruginosa or Staphylococcus aureus and on animal cells that were in contact with these coatings. We identified a unique range of Ag content that provided an effective antibacterial peak release, followed by cytocompatible conditions soon thereafter. The control of the in situ growth conditions for Ag nanoparticles in the polymer matrix offers the possibility to produce customized coatings that initially release sufficient quantities of Ag ions to produce a strong adjacent antibacterial effect, and at the same time exhibit a rapidly decaying Ag content to provide surface cytocompatibility within hours/days. This approach seems to be favourable with respect to implant surfaces and possible Ag-resistance/tolerance built-up.

Molecular cloning of a novel human I-mfa domain-containing protein that differently regulates human T-cell leukemia virus type I and HIV-1 expression.

Regulation of viral genome expression is the result of complex cooperation between viral proteins and host cell factors. We report here the characterization of a novel cellular factor sharing homology with the specific cysteine-rich C-terminal domain of the basic helix-loop-helix repressor protein I-mfa. The synthesis of this new factor, called HIC for Human I-mfa domain-Containing protein, is controlled at the translational level by two different codons, an ATG and an upstream non-ATG translational initiator, allowing the production of two protein isoforms, p32 and p40, respectively. We show that the HIC protein isoforms present different subcellular localizations, p32 being mainly distributed throughout the cytoplasm, whereas p40 is targeted to the nucleolus. Moreover, in trying to understand the function of HIC, we have found that both isoforms stimulate in T-cells the expression of a luciferase reporter gene driven by the human T-cell leukemia virus type I-long terminal repeat in the presence of the viral transactivator Tax. We demonstrate by mutagenesis that the I-mfa-like domain of HIC is involved in this regulation. Finally, we also show that HIC is able to down-regulate the luciferase expression from the human immunodeficiency virus type 1-long terminal repeat induced by the viral transactivator Tat. From these results, we propose that HIC and I-mfa represent two members of a new family of proteins regulating gene expression and characterized by a particular cysteine-rich C-terminal domain.

Genome-wide association study of virologic response with efavirenz-containing or abacavir-containing regimens in AIDS clinical trials group protocols.

BACKGROUND: Efavirenz and abacavir are components of recommended first-line regimens for HIV-1 infection. We used genome-wide genotyping and clinical data to explore genetic associations with virologic failure among patients randomized to efavirenz-containing or abacavir-containing regimens in AIDS Clinical Trials Group (ACTG) protocols. PARTICIPANTS AND METHODS: Virologic response and genome-wide genotype data were available from treatment-naive patients randomized to efavirenz-containing (n=1596) or abacavir-containing (n=786) regimens in ACTG protocols 384, A5142, A5095, and A5202. RESULTS: Meta-analysis of association results across race/ethnic groups showed no genome-wide significant associations (P<5×10) with virologic response for either efavirenz or abacavir. Our sample size provided 80% power to detect a genotype relative risk of 1.8 for efavirenz and 2.4 for abacavir. Analyses focused on CYP2B genotypes that define the lowest plasma efavirenz exposure stratum did not show associations nor did analysis limited to gene sets predicted to be relevant to efavirenz and abacavir disposition. CONCLUSION: No single polymorphism is associated strongly with virologic failure with efavirenz-containing or abacavir-containing regimens. Analyses to better consider context, and that minimize confounding by nongenetic factors, may show associations not apparent here.

Predicting the physicochemical profile of diastereoisomeric histidine-containing dipeptides by property space analysis.

OBJECTIVES: This study aimed at measuring the lipophilicity and ionization constants of diastereoisomeric dipeptides, interpreting them in terms of conformational behavior, and developing statistical models to predict them. METHODS: A series of 20 dipeptides of general structure NH(2) -L-X-(L or D)-His-OMe was designed and synthetized. Their experimental ionization constants (pK(1) , pK(2) and pK(3) ) and lipophilicity parameters (log P(N) and log D(7.4) ) were measured by potentiometry. Molecular modeling in three media (vacuum, water, and chloroform) was used to explore and sample their conformational space, and for each stored conformer to calculate their radius of gyration, virtual log P (preferably written as log P(MLP) , meaning obtained by the molecular lipophilicity potential (MLP) method) and polar surface area (PSA). Means and ranges were calculated for these properties, as was their sensitivity (i.e., the ratio between property range and number of rotatable bonds). RESULTS: Marked differences between diastereoisomers were seen in their experimental ionization constants and lipophilicity parameters. These differences are explained by molecular flexibility, configuration-dependent differences in intramolecular interactions, and accessibility of functional groups. Multiple linear equations correlated experimental lipophilicity parameters and ionization constants with PSA range and other calculated parameters. CONCLUSION: This study documents the differences in lipophilicity and ionization constants between diastereoisomeric dipeptides. Such configuration-dependent differences are shown to depend markedly on differences in conformational behavior and to be amenable to multiple linear regression. Chirality 24:566-576, 2012. © 2012 Wiley Periodicals, Inc.

Update on the non-prewhitening model observer in computed tomography for the assessment of the adaptive statistical and model-based iterative reconstruction algorithms.

The state of the art to describe image quality in medical imaging is to assess the performance of an observer conducting a task of clinical interest. This can be done by using a model observer leading to a figure of merit such as the signal-to-noise ratio (SNR). Using the non-prewhitening (NPW) model observer, we objectively characterised the evolution of its figure of merit in various acquisition conditions. The NPW model observer usually requires the use of the modulation transfer function (MTF) as well as noise power spectra. However, although the computation of the MTF poses no problem when dealing with the traditional filtered back-projection (FBP) algorithm, this is not the case when using iterative reconstruction (IR) algorithms, such as adaptive statistical iterative reconstruction (ASIR) or model-based iterative reconstruction (MBIR). Given that the target transfer function (TTF) had already shown it could accurately express the system resolution even with non-linear algorithms, we decided to tune the NPW model observer, replacing the standard MTF by the TTF. It was estimated using a custom-made phantom containing cylindrical inserts surrounded by water. The contrast differences between the inserts and water were plotted for each acquisition condition. Then, mathematical transformations were performed leading to the TTF. As expected, the first results showed a dependency of the image contrast and noise levels on the TTF for both ASIR and MBIR. Moreover, FBP also proved to be dependent of the contrast and noise when using the lung kernel. Those results were then introduced in the NPW model observer. We observed an enhancement of SNR every time we switched from FBP to ASIR to MBIR. IR algorithms greatly improve image quality, especially in low-dose conditions. Based on our results, the use of MBIR could lead to further dose reduction in several clinical applications.

Revisiting spatial distribution and biochemical composition of calcium-containing crystals in human osteoarthritic articular cartilage.

INTRODUCTION: Calcium-containing (CaC) crystals, including basic calcium phosphate (BCP) and calcium pyrophosphate dihydrate (CPP), are associated with destructive forms of osteoarthritis (OA). We assessed their distribution and biochemical and morphologic features in human knee OA cartilage. METHODS: We prospectively included 20 patients who underwent total knee replacement (TKR) for primary OA. CaC crystal characterization and identification involved Fourier-transform infra-red spectrometry and scanning electron microscopy of 8 to 10 cartilage zones of each knee, including medial and lateral femoral condyles and tibial plateaux and the intercondyle zone. Differential expression of genes involved in the mineralization process between cartilage with and without calcification was assessed in samples from 8 different patients by RT-PCR. Immunohistochemistry and histology studies were performed in 6 different patients. RESULTS: Mean (SEM) age and body mass index of patients at the time of TKR was 74.6 (1.7) years and 28.1 (1.6) kg/m², respectively. Preoperative X-rays showed joint calcifications (chondrocalcinosis) in 4 cases only. The medial femoro-tibial compartment was the most severely affected in all cases, and mean (SEM) Kellgren-Lawrence score was 3.8 (0.1). All 20 OA cartilages showed CaC crystals. The mineral content represented 7.7% (8.1%) of the cartilage weight. All patients showed BCP crystals, which were associated with CPP crystals for 8 joints. CaC crystals were present in all knee joint compartments and in a mean of 4.6 (1.7) of the 8 studied areas. Crystal content was similar between superficial and deep layers and between medial and femoral compartments. BCP samples showed spherical structures, typical of biological apatite, and CPP samples showed rod-shaped or cubic structures. The expression of several genes involved in mineralization, including human homolog of progressive ankylosis, plasma-cell-membrane glycoprotein 1 and tissue-nonspecific alkaline phosphatase, was upregulated in OA chondrocytes isolated from CaC crystal-containing cartilages. CONCLUSIONS: CaC crystal deposition is a widespread phenomenon in human OA articular cartilage involving the entire knee cartilage including macroscopically normal and less weight-bearing zones. Cartilage calcification is associated with altered expression of genes involved in the mineralisation process.

Emission of carbon nanofiber (CNF) from CNF-containing composite adsorbents

In spite of numerous applications of carbon nanofibers (CNFs) in a variety of fields, the potential release of airborne CNF during their special application, which could lead to workers or end-users exposure, has not been well investigated. In this study, the potential release of CNF from an organic vapour respirator cartridge was evaluated by carbon analysis and microscopy analysis. The cartridge consisted of an AC (Activated Carbon)/CNF composite adsorbent and different types of particulate filters. The composite adsorbent CNF were prepared by chemical vapour deposition (CVD). Air was passed through the prepared cartridge for 12 hours at 12 l/min and particles were collected on sampling filters suitable for measuring organic and elemental carbon (OC/EC) by carbon analysis based on the NIOSH 5040 method. Breakthrough of CNFs was also checked by scanning and transmission electron microscopy (SEM/TEM). This study found only minimal amounts of released elemental carbon while passing the air through the cartridge. Meanwhile TEM photos showed a few CNF structures for AC/CNF composite adsorbents which were not in the critical range in terms of length, aspect ratio, or number. [Authors]

Mineral zoning and geochemistry of epithermal polymetallic Zn-Pb-Ag-Cu-Bi mineralization at Cerro de Pasco, Peru

The large Cerro de Pasco Cordilleran base metal deposit in central Peru is located on the eastern margin of a middle Miocene diatreme-dome complex and comprises two mineralization stages. The first stage consists of a large pyrite-quartz body replacing Lower Mesozoic Pucara carbonate rocks and, to a lesser extent, diatreme breccia. This body is composed of pyrite with pyrrhotite inclusions, quartz, and black and red chalcedony (containing hypogene hematite). At the contact with the pyrite-quartz body, the diatreme breccia is altered to pyrite-quartz-sericite-pyrite. This body was, in part, replaced by pipelike pyrrhotite bodies zoned outward to carbonate-replacement Zn-Pb ores hearing Fe-rich sphalerite (up to 24 mol % Fes). The second mineralization stage is partly superimposed on the first and consists of zoned east-west-trending Cu-Ag-(Au-Zn-Pb) enargite-pyrite veins hosted in the diatreme breccia in the western part of the deposit and well-zoned Zn-Pb-(Bi-Ag-Cu) carbonate-replacement orebodies; in both cases, sphalerite is Fe poor and the inner parts of the orebodies show typically advanced argillic alteration assemblages, including aluminum phosphate Sulfate (APS) minerals. The zoned enargite-pyrite veins display mineral zoning, from a core of enargite-pyrite +/- alunite with traces of Au, through an intermediate zone of tennantite, chalcopyrite, and Bi minerals to a poorly developed Outer zone hearing sphalerite-galena +/- kaolinite. The carbonate-hosted replacement ores are controlled along N 35 degrees E, N 90 degrees E, N 120 degrees E, and N 170 degrees E faults. They form well-zoned upward-flaring pipelike orebodies with a core of famatinite-pyrite and alunite, an intermediate zone with tetrahedrite-pyrite, chalcopyrite, matildite, cuprobismutite, emplectite, and other Bi minerals accompanied by APS minerals, kaolinite, and dickite, and an outer zone composed of Fe-poor sphalerite (in the range of 0.05-3.5 mol % Fes) and galena. The outermost zone consists of hematite, magnetite, and Fe-Mn-Zn-Ca-Mg carbonates. Most of the second-stage carbonate-replacement orebodies plunge between 25 degrees and 60 degrees to the west, suggesting that the hydrothermal fluids ascended from deeper levels and that no lateral feeding from the veins to the carbonate-replacement orebodies took place. In the Venencocha and Santa Rosa areas, located 2.5 km northwest of the Cerro de Pasco open pit and in the southern part of the deposit, respectively, advanced argillic altered dacitic domes and oxidized veins with advanced argillic alteration halos occur. The latter veins are possibly the oxidized equivalent of the second-stage enargite-pyrite veins located in the western part of the deposit. The alteration assemblage quartz-muscovite-pyrite associated with the pyrite-quartz body suggests that the first stage precipitated at slightly, acidic fin. The sulfide mineral assemblages define an evolutionary path close to the pyrite-pyrrhotite boundary and are characteristic of low-sulfidation states; they suggest that the oxidizing slightly acidic hydrothermal fluid was buffered by phyllite, shale, and carbonate host rock. However, the presence in the pyrite-quartz body of hematite within quartz suggests that, locally, the fluids were less buffered by the host rock. The mineral assemblages of the second mineralization stage are characteristic of high- to intermediate-sulfidation states. High-sulfidation states and oxidizing conditions were achieved and maintained in the cores of the second-stage orebodies, even in those replacing carbonate rocks. The observation that, in places, second-stage mineral assemblages are found in the inner and outer zones is explained in terms of the hydrothermal fluid advancing and waning. Microthermometric data from fluid inclusions in quartz indicate that the different ores of the first mineralization stage formed at similar temperatures and moderate salinities (200 degrees-275 degrees C and 0.2-6.8 wt % NaCl equiv in the pyrite-quartz body; 192 degrees-250 degrees C and 1.1-4.3 wt % NaCl equiv in the pyrrhotite bodies; and 183 degrees-212 degrees C and 3.2-4.0 wt % NaCl equiv in the Zn-Pb ores). These values are similar to those obtained for fluid inclusions in quartz and sphalerite from the second-stage ores (187 degrees-293 degrees C and 0.2-5.2 wt % NaCl equiv in the enargite-pyrite veins: 178 degrees-265 degrees C and 0.2-7.5 wt % NaCl equiv in quartz of carbonate-replacement orebodies; 168 degrees-999 degrees C and 3-11.8 wt % NaCl equiv in sphalerite of carbonate-replacement orebodies; and 245 degrees-261 degrees C and 3.2-7.7 wt % NaCl equiv in quartz from Venencocha). Oxygen and hydrogen isotope compositions oil kaolinite from carbonate-replacement orebodies (delta(18)O = 5.3-11.5%o, delta D = -82 to -114%o) and on alunite from the Venencocha and Santa Rosa areas (delta(18)O = 1.9-6.9%o, delta D = -56 to -73%o). Oxygen isotope compositions of quartz from the first and second stages have 6180 values from 9.1 to 1.7.8 per mil. Calculated fluids in equilibrium with kaolinite have delta(18)O values of 2.0 to 8.2 and delta D values of -69 to -97 per mil; values in equilibrium with alunite are -1.4 to -6.4 and -62 to -79 per mil. Sulfur isotope compositions of sulfides from both stages have a narrow range of delta(34)S values, between -3.7 and +4.2 per mil; values for sulfates from the second stage are between 4.2 and 31.2 per mil. These results define two mixing trends for the ore-forming fluids. The first trend reflects mixing between a moderately saline (similar to 10 wt % NaCl equiv) magmatic end member that had degassed (as indicated by the low delta D values) and meteoric water. The second mixing indicates condensation of magmatic vapor with HCl and SO(2) into meteoric water, which formed alunite. The hydrothermal system at Cerro de Pasco was emplaced at a shallow depth (similar to 500 m) in the epithermal and upper part of a porphyry environment. The similar temperatures and salinities obtained for the first stage and second stages, together with the stable isotope data, indicate that both stages are linked and represent successive stages of epithermal polymetallic mineralization in the upper part of a porphyry system.

Exploring the space of histidine containing dipeptides in search of novel efficient RCS sequestering agents.

The study reports a set of forty proteinogenic histidine-containing dipeptides as potential carbonyl quenchers. The peptides were chosen to cover as exhaustively as possible the accessible chemical space, and their quenching activities toward 4-hydroxy-2-nonenal (HNE) and pyridoxal were evaluated by HPLC analyses. The peptides were capped at the C-terminus as methyl esters or amides to favor their resistance to proteolysis and diastereoisomeric pairs were considered to reveal the influence of configuration on quenching. On average, the examined dipeptides are less active than the parent compound carnosine (βAla + His) thus emphasizing the unfavorable effect of the shortening of the βAla residue as confirmed by the control dipeptide Gly-His. Nevertheless, some peptides show promising activities toward HNE combined with a remarkable selectivity. The results emphasize the beneficial role of aromatic and positively charged residues, while negatively charged and H-bonding side chains show a detrimental effect on quenching. As a trend, ester derivatives are slightly more active than amides while heterochiral peptides are more active than their homochiral diastereoisomer. Overall, the results reveal that quenching activity strongly depends on conformational effects and vicinal residues (as evidenced by the reported QSAR analysis), offering insightful clues for the design of improved carbonyl quenchers and to rationalize the specific reactivity of histidine residues within proteins.