Resveratrol prevents renal lipotoxicity and inhibits mesangial cell glucotoxicity in a manner dependent on the AMPK-SIRT1-PGC1α axis in db/db mice

AIMS/HYPOTHESIS

Many of the effects of resveratrol are consistent with the activation of AMP-activated protein kinase (AMPK), silent information regulator T1 (SIRT1) and peroxisome proliferator-activated receptor (PPAR)γ co-activator 1α (PGC-1α), which play key roles in the regulation of lipid and glucose homeostasis, and in the control of oxidative stress. We investigated whether resveratrol has protective effects on the kidney in type 2 diabetes.

METHODS

Four groups of male C57BLKS/J db/m and db/db mice were used in this study. Resveratrol was administered via gavage to diabetic and non-diabetic mice, starting at 8 weeks of age, for 12 weeks.

RESULTS

The db/db mice treated with resveratrol had decreased albuminuria. Resveratrol ameliorated glomerular matrix expansion and inflammation. Resveratrol also lowered the NEFA and triacylglycerol content of the kidney, and this action was related to increases in the phosphorylation of AMPK and the activation of SIRT1-PGC-1α signalling and of the key downstream effectors, the PPARα-oestrogen-related receptor (ERR)-1α-sterol regulatory element-binding protein 1 (SREBP1). Furthermore, resveratrol decreased the activity of phosphatidylinositol-3 kinase (PI3K)-Akt phosphorylation and class O forkhead box (FOXO)3a phosphorylation, which resulted in a decrease in B cell leukaemia/lymphoma 2 (BCL-2)-associated X protein (BAX) and increases in BCL-2, superoxide dismutase (SOD)1 and SOD2 production. Consequently, resveratrol reversed the increase in renal apoptotic cells and oxidative stress, as reflected by renal 8-hydroxy-deoxyguanosine (8-OH-dG), urinary 8-OH-dG and isoprostane concentrations. Resveratrol prevented high-glucose-induced oxidative stress and apoptosis in cultured mesangial cells through the phosphorylation of AMPK and activation of SIRT1-PGC-1α signalling and the downstream effectors, PPARα-ERR-1α-SREBP1.

CONCLUSIONS/INTERPRETATION

The results suggest that resveratrol prevents diabetic nephropathy in db/db mice by the phosphorylation of AMPK and activation of SIRT1-PGC-1α signalling, which appear to prevent lipotoxicity-related apoptosis and oxidative stress in the kidney.

The induction of intercellular adhesion molecule 1 (ICAM-1) expression on human fetal astrocytes by interferon-gamma, tumor necrosis factor alpha, lymphotoxin, and interleukin-1: relevance to intracerebral antigen presentation

Antigen presentation reactions are dependent upon the expression of the class II major histocompatibility antigens (MHC), the T-cell receptor, and the presented antigen. Recent studies demonstrate that such processes also require the presence of adhesion molecules such as lymphocyte functional antigen 1 (LFA-1) and its cell surface ligand, intercellular adhesion molecule 1 (ICAM-1). It has been suggested that the brain astrocyte can function as a facultative antigen presenting cell (APC). This hypothesis is based upon the ability to induce the expression of the class II MHC antigens on astrocytes, and on their ability to present myelin basic protein to encephalitogenic T-cells in vitro. The best in vivo data showing that astrocytes serve as intracerebral APCs is the finding that astrocytes in multiple sclerosis plaques are DR+ (class II MHC in human). However, it still remains to be resolved whether the in vivo expression of the MHC antigens in disease states is instrumental to antigen presentation mechanisms or whether these cell surface glycoproteins are expressed secondary to brain immune responses. If astrocytes function as immunocompetent APCs within the brain, it would seem that they would also be able to express molecules important for intercellular adhesion. Here, we present the first data that indicates that human astrocytes are capable of expressing ICAM-1 in response to cytokines that either induce or upregulate the expression of DR. In essence, cytokines derived from different cell types seem to exert similar pleiotropic effects on the modulation of MHC and ICAM-1 expression on astrocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Contrasting structural impacts induced by cis-syn cyclobutane dimer and (6-4) adduct in DNA duplex decamers: implication in mutagenesis and repair activity

The relative biological importance of cis--syn cyclobutane dimer and pyrimidine(6-4)pyrimidone photoadduct ([6-4] photoadduct) appears to be dependent on the biological species, dipyrimidine sites and local conformational variation induced at the damaged sites. The single-strained deoxynucleotide 10-mers containing the site-specific (6-4) adduct or cis--syn cyclobutane dimer of thymidylyl(3'-->5')-thymidine were generated by direct photolysis of d(CGCATTACGC) with UVC (220-260 nm) irradiation or UVB (260-320 nm) photosensitization. Three-dimensional structures of the duplex cis--syn and (6-4) decamers of d(CGCATTACGC)xd(GCGTAATGCG) were determined by NMR spectroscopy and the relaxation matrix refinement method. The NMR data and structural calculations establish that Watson-Crick base pairing is still intact at the cis--syn dimer site while the hydrogen bonding is absent at the 3'-side of the (6-4) lesion where the T-->C transition mutation is predominantly targeted. Overall conformation of the duplex cis--syn decamer was B-DNA and produced a 9 degree bending in the DNA helix, but a distinctive base orientation of the (6-4) lesion provided a structural basis leading to 44 degree helical bending. The observed local structure and conformational rigidity at the (6-4) adduct of the thymidylyl(3'-5')-thymidine (T-T [6-4]) lesion site suggest the potential absence of hydrogen bonding at the 3' sides of the (6-4) lesion with a substituted nucleotide during replication under SOS conditions. Contrasting structural distortions induced ny the T-T (6-4) adduct with respect to the T-T cis--syn cyclobutane pyrimidine photodimer may explain the large differences in mutation spectrum and repair activities between them.

Intracellular correlates of fast (>200 Hz) electrical oscillations in rat somatosensory cortex

Oscillatory activity in excess of several hundred hertz has been observed in somatosensory evoked potentials (SEP) recorded in both humans and animals and is attracting increasing interest regarding its role in brain function. Currently, however, little is known about the cellular events underlying these oscillations. The present study employed simultaneous in-vivo intracellular and epipial field-potential recording to investigate the cellular correlates of fast oscillations in rat somatosensory cortex evoked by vibrissa stimulation. Two distinct types of fast oscillations were observed, here termed "fast oscillations" (FO) (200-400 Hz) and "very fast oscillations" (VFO) (400-600 Hz). FO coincided with the earliest slow-wave components of the SEP whereas VFO typically were later and of smaller amplitude. Regular spiking (RS) cells exhibited vibrissa-evoked responses associated with one or both types of fast oscillations and consisted of combinations of spike and/or subthreshold events that, when superimposed across trials, clustered at latencies separated by successive cycles of FO or VFO activity, or a combination of both. Fast spiking (FS) cells responded to vibrissae stimulation with bursts of action potentials that closely approximated the periodicity of the surface VFO. No cells were encountered that produced action potential bursts related to FO activity in an analogous fashion. We propose that fast oscillations define preferred latencies for action potential generation in cortical RS cells, with VFO generated by inhibitory interneurons and FO reflecting both sequential and recurrent activity of stations in the cortical lamina.

The solution structure of DNA duplex-decamer containing the (6-4) photoproduct of thymidylyl(3'-->5')thymidine by NMR and relaxation matrix refinement

The DNA duplex-decamer containing a site-specific (6-4) photoadduct of thymidylyl(3'-->5')thymidine was generated by direct photolytic ultraviolet C irradiation of d(CGCATTACGC). The three-dimensional structure of the duplex (6-4) decamer, d(CGCAT[6-4]TACGC).d(GCGTAATGCG), has been determined by two-dimensional NMR spectroscopy and a relaxation matrix refinement method. NMR data and structural calculations established that the formation of the (6-4) adduct in the B-DNA duplex retains Watson-Crick-type hydrogen bonding throughout the duplex except at the 3'-side of the (6-4) lesion where the T-->C transition mutation is predominantly targeted [LeClerc, J. E., Borden, A. & Lawrence, C. W. (1991) Proc. Natl Acad. Sci. USA 88, 9685-9689], but leads to a 44 degrees bending in the overall DNA helix. Perpendicular base orientation of the (6-4) lesion provides a structural basis where potential hydrogen bonding at the 3' sides of the (6-4) adduct with substituted nucleotide is improbable during replication under stringent conditions.

Dark matter results from 225 live days of XENON100 data

We report on a search for particle dark matter with the XENON100 experiment, operated at the Laboratori Nazionali del Gran Sasso for 13 months during 2011 and 2012. XENON100 features an ultralow electromagnetic background of (5.3 ± 0.6) × 10(-3) events/(keV(ee) × kg × day) in the energy region of interest. A blind analysis of 224.6 live days × 34 kg exposure has yielded no evidence for dark matter interactions. The two candidate events observed in the predefined nuclear recoil energy range of 6.6-30.5 keV(nr) are consistent with the background expectation of (1.0 ± 0.2) events. A profile likelihood analysis using a 6.6-43.3 keV(nr) energy range sets the most stringent limit on the spin-independent elastic weakly interacting massive particle-nucleon scattering cross section for weakly interacting massive particle masses above 8 GeV/c(2), with a minimum of 2 × 10(-45) cm(2) at 55 GeV/c(2) and 90% confidence level.

Intracranial stenting of severe symptomatic intracranial stenosis: results of 100 consecutive patients

BACKGROUND AND PURPOSE

There are a few reports regarding the outcome evaluation of balloon-expandable intracranial stent placement (BEICS). The purpose of our study was to evaluate the outcome and factors related to the adverse events (AEs) of BEICS.

MATERIALS AND METHODS

We evaluated 100 consecutive patients who underwent BEICS. We assessed the procedural success (residual stenosis < 50%), AEs (minor strokes, major strokes, and death), clinical outcome, and restenosis (> 50%) at 6 months. We also analyzed 18 factors including symptom patterns related to AE rate. Symptom patterns revealed 1) stable patients (n = 73) with improving, stationary, or resolved symptoms; and 2) unstable patients (n = 27) with gradual worsening or fluctuating symptoms (National Institutes of Health Stroke Scale [NIHSS] > or = 4) within 2 days before stent placement.

RESULTS

The procedural success rate was 99%. Overall, there were 10 (10%) AEs within the 6 months: 4 (4%) minor strokes, 3 (3%) major strokes, and 3 (3%) deaths including a death from myocardial infarction. AE rate was 4.1% in stable and 25.9% in unstable patients. Restenosis at 6 months revealed 0% (0/59). Good outcome (modified Rankin Scale < or = 2) at 6 months was 97% (71/73) in stable and 67% (18/27) in unstable patients. Stepwise logistic regression model revealed that symptom pattern (unstable versus stable) was the only significant risk factor (OR, 8.167; 95% CI, 1.933-34.500; P = .004).

CONCLUSION

BEICS revealed a low AE and good outcome rate at 6 months, especially in the stable patients. Midterm outcome was also favorable in the unstable patient group.

Effect of adrenergic receptor activation on post-herpetic neuralgia pain and sensory disturbances

Patients with acute herpes zoster, and to a lesser extent post-herpetic neuralgia (PHN), have been reported to respond to local anesthetic blockade of the sympathetic nervous system. In animal models of nerve injury, local injection of adrenergic agonists after nerve injury, but not before, excites nociceptors. In some patients with chronic neuropathic pain, local application of norepinephrine evokes pain. In 15 subjects with PHN, the role of adrenergic receptors in PHN pain was assessed in a two-session double blind study comparing the response to cutaneous infiltration of epinephrine or phenylephrine (30 micrograms in 3 ml) with the response to normal saline in both the painfully affected skin and mirror-image normal skin. Two adjacent sites were studied on each side of the body, one site for injection and the other for measuring sensory effects of the injection. In the morning part of each session, mirror-image normal skin was injected. In the afternoon portion of each session, skin in the most painful area affected by PHN was injected. Injection of saline or the adrenergic agonist in normal skin produced mild and transient pain without development of allodynia and without affecting overall PHN pain intensity. In PHN skin, injection of saline and the adrenergic agonist produced an equivalent degree of transient pain that was slightly greater than injection into mirror-image normal skin. After injection of the adrenergic agonist into PHN skin, both overall PHN pain and allodynia severity were significantly greater than after saline injection, peaking at 10-15 min post-injection. Even when PHN has been present for years, adrenergic receptor stimulation in PHN skin increases pain, most likely through direct activation of C-nociceptors in the painful skin. Increased allodynia is most likely mediated centrally and driven by the increase in C-nociceptor input.

Structural features of an influenza virus promoter and their implications for viral RNA synthesis

The influenza A virus, a severe pandemic pathogen, has a segmented RNA genome consisting of eight single-stranded RNA molecules. The 5' and 3' ends of each RNA segment recognized by the influenza A virus RNA-dependent RNA polymerase direct both transcription and replication of the virus's RNA genome. Promoter binding by the viral RNA polymerase and formation of an active open complex are prerequisites for viral replication and proliferation. Here we describe the solution structure of this promoter as solved by multidimensional, heteronuclear magnetic resonance spectroscopy. Our studies show that the viral promoter has a significant dynamic nature and reveal an unusual displacement of an adenosine that forms a novel (A-A) x U motif and a C-A mismatch stacked in a helix. The characterized structural features of the promoter imply that the specificity of polymerase binding results from an internal RNA loop. In addition, an unexpected bending (46 +/- 10 degrees ) near the initiation site suggests the existence of a promoter recognition mechanism similar to that of DNA-dependent RNA polymerase and a possible regulatory function for the terminal structure during open complex formation.

Analysis of thermal relaxation during laser irradiation of tissue

BACKGROUND AND OBJECTIVE

Thermal relaxation time (tau(r)) is a commonly-used parameter for estimating the time required for heat to conduct away from a directly-heated tissue region. Previous studies have demonstrated that temperature superposition can occur during multiple-pulse irradiation, even if the interpulse time is considerably longer than tau(r). The objectives of this study were (1) to analyze tissue thermal relaxation following laser-induced heating, and (2) to calculate the time required for a laser-induced temperature rise to decrease to near-baseline values.

STUDY DESIGN/MATERIALS AND METHODS

One-dimensional (1-D) analytical and numerical and 2-D numerical models were designed and used for calculations of the time tau(eff) required for the peak temperature (T(peak)) to decrease to values slightly over baseline (DeltaT(base)). Temperature values included T(peak)=65 and 100 degrees C, and DeltaT(base) = 5, 10, and 20 degrees C. To generalize the calculations, a wide range of optical and thermal properties was incorporated into the models. Flattop and gaussian spatial beam profiles were also considered.

RESULTS

2-D model calculations of tau(eff) demonstrated that tau(eff) (2-D) was as much as 40 times longer than tau(r). For a given combination of T(peak) and DeltaT(base), a linear relationship was calculated between tau(eff) (1-D) and tau(r) and was independent of optical and thermal properties. A comparison of 1-D and 2-D models demonstrated that 1-D models generally predicted longer values of tau(eff) than those predicted with a 2-D geometry when the laser spot diameter was equal to or less than the optical penetration depth.

CONCLUSION

Relatively simple calculations can be performed to estimate tau(eff) for known values of tau(r), T(peak) and DeltaT(base). The parameter tau(eff) may be a better estimate than tau(r) of tissue thermal relaxation during multiple-pulse laser irradiation.

Transverse-momentum and collision-energy dependence of high-pT hadron suppression in Au+Au collisions at ultrarelativistic energies

We report high statistics measurements of inclusive charged hadron production in Au+Au and p+p collisions at sqrt[s(NN)]=200 GeV. A large, approximately constant hadron suppression is observed in central Au+Au collisions for 5<p(T)<12 GeV/c. The collision energy dependence of the yields and the centrality and p(T) dependence of the suppression provide stringent constraints on theoretical models of suppression. Models incorporating initial-state gluon saturation or partonic energy loss in dense matter are largely consistent with observations. We observe no evidence of p(T)-dependent suppression, which may be expected from models incorporating jet attenuation in cold nuclear matter or scattering of fragmentation hadrons.

Centrality dependence of high-p(T) hadron suppression in Au+Au collisions at sqrt[s(NN)]=130 GeV

Inclusive transverse momentum distributions of charged hadrons within 0.2<p(T)<6.0 GeV/c have been measured over a broad range of centrality for Au+Au collisions at sqrt[s(NN)]=130 GeV. Hadron yields are suppressed at high p(T) in central collisions relative to peripheral collisions and to a nucleon-nucleon reference scaled for collision geometry. Peripheral collisions are not suppressed relative to the nucleon-nucleon reference. The suppression varies continuously at intermediate centralities. The results indicate significant nuclear medium effects on high-p(T) hadron production in heavy-ion collisions at high energy.

The effect of TNFα secreted from macrophages activated by titanium particles on osteogenic activity regulated by WNT/BMP signaling in osteoprogenitor cells

Wear particles are the major cause of osteolysis associated with failure of implant following total joint replacement. During this pathologic process, activated macrophages mediate inflammatory responses to increase osteoclastogenesis, leading to enhanced bone resorption. In osteolysis caused by wear particles, osteoprogenitors present along with macrophages at the implant interface may play significant roles in bone regeneration and implant osteointegration. Although the direct effects of wear particles on osteoblasts have been addressed recently, the role of activated macrophages in regulation of osteogenic activity of osteoblasts has scarcely been studied. In the present study, we examined the molecular communication between macrophages and osteoprogenitor cells that may explain the effect of wear particles on impaired bone forming activity in inflammatory bone diseases. It has been demonstrated that conditioned medium of macrophages challenged with titanium particles (Ti CM) suppresses early and late differentiation markers of osteoprogenitors, including alkaline phosphatase (ALP) activity, collagen synthesis, matrix mineralization and expression of osteocalcin and Runx2. Moreover, bone forming signals such as WNT and BMP signaling pathways were inhibited by Ti CM. Interestingly, TNFα was identified as a predominant factor in Ti CM to suppress osteogenic activity as well as WNT and BMP signaling activity. Furthermore, Ti CM or TNFα induces the expression of sclerostin (SOST) which is able to inhibit WNT and BMP signaling pathways. It was determined that over-expression of SOST suppressed ALP activity, whereas the inhibition of SOST by siRNA partially restored the effect of Ti CM on ALP activity. This study highlights the role of activated macrophages in regulation of impaired osteogenic activity seen in inflammatory conditions and provides a potential mechanism for autocrine regulation of WNT and BMP signaling mediated by TNFα via induction of SOST in osteprogenitor cells.

Curcumin suppresses Streptococcus mutans adherence to human tooth surfaces and extracellular matrix proteins

Streptococcus mutans is the key causative agent of caries and infective endocarditis. The first step in biofilm development and the consequent initiation of further disease is bacterial adherence to host cell surfaces. Therefore, the aim of this study was to evaluate the inhibitory effect of curcumin on S. mutans adherence to extracellular matrices and tooth surfaces. The effect of curcumin on the ability of S. mutans to adhere to glass surfaces coated with collagen and fibronectin was tested in order to determine whether the decrease of the bacterial adhesion by curcumin is achieved by hindering the bacteria in adhering to collagen and/or fibronectin. Also, human teeth inoculated with S. mutans were treated with curcumin in vitro in order to assess the relevance of the anti-adhesive effect to oral conditions in vivo. The minimum inhibitory concentration (MIC) at which curcumin completely inhibited bacterial growth was 128 μg/mL. The addition of curcumin below the MIC diminished bacterial adherence onto both collagen- and fibronectin-coated glass surfaces and human tooth surfaces. It appears that the anti-adhesive effect of curcumin against S. mutans is mediated through collagen and fibronectin. These results support the widespread use of curcumin as a food-based antimicrobial agent.

Identification of oral spirochetes at the species level and their association with other bacteria in endodontic infections

OBJECTIVES

Recent molecular approaches have revealed that fastidious organisms such as Bacteroides forsythus and oral treponemes were frequently found in root canals with apical periodontitis. The purpose of this study was to identify the isolates of oral spirochetes at the species level in endodontic infections and to determine their association with B forsythus and Porphyromonas gingivalis.

STUDY DESIGN

Seventy-nine teeth with apical periodontitis were selected for this study. After sampling from the root canals aseptically, polymerase chain reaction amplification for the 16S rRNA gene was performed with eubacterial universal primers. Subsequently, dot-blot hybridization was performed with 8 species-specific oligonucleotide probes. The microbial associations were analyzed by using the odds ratio.

RESULTS

The most frequently found species was P gingivalis (27.4%), followed by Treponema maltophilum (26%), B forsythus (16.4%), and Treponema socranskii (2.7%). Other treponemes, including Treponema denticola, were not detected in our samples. Significant microbial associations were identified between T maltophilum, B forsythus, and P gingivalis by performing analysis with the odds ratio.

CONCLUSION

Our results indicate that T maltophilum should be included in etiologic studies of endodontic diseases.

An estimation of the first positive Lyapunov exponent of the EEG in patients with schizophrenia

We studied the complexity of the electroencephalogram (EEG) in schizophrenic patients by estimating the first Lyapunov exponent (L1), which might serve as an indicator of the specific brain function in schizophrenia. We recorded the EEG from 25 schizophrenic patients (12 male, 13 female; age=25.1+/-7.0 years) fulfilling DSM-IV criteria and 15 healthy controls (9 male, 6 female; age=27. 8+/-4.2 years) at 16 electrodes, different from previous studies which recorded the EEGs at limited electrodes. We employed a method with an optimal embedding dimension to calculate the L1s. For limited noisy data, this algorithm was strikingly faster and more accurate than previous ones. Our results showed that the schizophrenic patients had lower values of the L1 at the left inferior frontal and anterior temporal regions compared with normal controls. These results for L1 in non-linear analysis have some differences from those for power ratios in linear analysis. These suggest that the non-linear analysis of the EEGs such as the estimation of the L1 might be a useful tool in analyzing EEG data to explore the neurodynamics of the brains of schizophrenic patients.

Solution structure of a DNA decamer duplex containing the stable 3' T.G base pair of the pyrimidine(6-4)pyrimidone photoproduct [(6-4) adduct]: implications for the highly specific 3' T --> C transition of the (6-4) adduct

The pyrimidine(6-4)pyrimidone photoproduct [(6-4) adduct] is one of the major photoproducts induced by UV irradiation of DNA and occurs at TpT sites. The (6-4) adduct is highly mutagenic and leads most often to a 3' T --> C transition with 85% replicating error frequency [LeClerc, J. E., Borden, A. & Lawrence, C. W. (1991) Proc. Natl. Acad. Sci. USA 88, 9685-9689]. To determine the origin of the specific 3' T --> C transition of the (6-4) adduct, we have used experimental NMR restraints and molecular dynamics to determine the solution structure of a (6-4)-lesion DNA decamer duplex that contains a mismatched base pair between the 3' T residue and an opposed G residue. Normal Watson-Crick-type hydrogen bonding is retained at the 5' T of the lesion site. The O2 carbonyl of the 3' T residue forms hydrogen bonds with the imino and amino protons of the opposed G residue. This potential hydrogen bonding stabilizes the overall helix and restores the highly distorted conformation of the (6-4) adduct to the typical B-form-like DNA structure. This structural feature can explain the marked preference for the insertion of an A residue opposite the 5' T and a G residue opposite the 3' T of the (6-4) lesion during trans-lesion synthesis. Thus these insertions yield the predominant 3' T --> C transition.

Identification of a cytoplasmic targeting/retention signal in a retroviral Gag polyprotein

Retroviral capsid assembly can occur by either of two distinct morphogenic processes: in type C viruses, the capsid assembles and buds at the plasma membrane, while in type B and D viruses, the capsid assembles within the cytoplasm and is then transported to the plasma membrane for budding. We have previously reported that a single-amino-acid substitution of a tryptophan for an arginine in the matrix protein (MA) of Mason-Pfizer monkey virus (MPMV) converts its capsid assembly from that of a type D retrovirus to that of the type C viruses (S. S. Rhee and E. Hunter, Cell 63:77-86, 1990). Here we identify a region of 18 amino acids within the MA of MPMV that is responsible for type D-specific morphogenesis. Insertion of these 18 amino acids into the MA of type C Moloney murine leukemia virus causes it to assemble an immature capsid in the cytoplasm. Furthermore, fusion of the MPMV MA to the green fluorescent protein resulted in altered intracellular targeting and a punctate accumulation of the fusion protein in the cytoplasm. These 18 amino acids, which are necessary and sufficient to target retroviral Gag polyproteins to defined sites in the cytoplasm, appear to define a novel mammalian cytoplasmic targeting/retention signal.

Disappearance of back-to-back high-pT hadron correlations in central Au+Au collisions at sqrt[s NN ] =200 GeV

Azimuthal correlations for large transverse momentum charged hadrons have been measured over a wide pseudorapidity range and full azimuth in Au+Au and p+p collisions at sqrt[s(NN)]=200 GeV. The small-angle correlations observed in p+p collisions and at all centralities of Au+Au collisions are characteristic of hard-scattering processes previously observed in high-energy collisions. A strong back-to-back correlation exists for p+p and peripheral Au+Au. In contrast, the back-to-back correlations are reduced considerably in the most central Au+Au collisions, indicating substantial interaction as the hard-scattered partons or their fragmentation products traverse the medium.

Pretransplant donor-specific interferon-gamma ELISPOT assay predicts acute rejection episodes in renal transplant recipients

Interferon (IFN)-gamma enzyme-linked immunosorbent spot (ELISPOT) assay is a powerful tool for measuring the frequency of alloantigen-specific T cells, reflecting cellular immunity. We correlated the pretransplant frequencies of donor-specific and third-party-specific IFN-gamma ELISPOT tests, with the posttransplant outcomes of 45 recipients of living donor renal transplantations. The mean frequency of pretransplant donor-specific ELISPOT was significantly greater among patients with acute rejection episodes (ARE) than those without ARE (18.0 [12 to 50] versus 8.8 [5 to 30.4]) spots per 200,000 peripheral blood lymphocytes (PBLs; P=.024). A cutoff level of 12 spots per 200,000 PBLs on the donor-specific ELISPOT identified an ARE-positive patient with a sensitivity of 81.8% and a specificity of 64.7%. The recipients with pretransplant donor-specific ELISPOT+showed higher serum creatinine levels and lower glomerular filtration rate (GFR) at 6 posttransplant months (P<.05). Although the pretransplant third-party-specific ELISPOT results correlated with the donor-specific ELISPOT results (r=.783; P<.001), there was no significant difference in the third-party ELISPOT results between the ARE-positive and ARE-negative recipients. In conclusion, an analysis of pretransplant donor-specific IFN-gamma ELISPOT may identify the posttransplant risk of developing ARE and displaying decreased GFR at 6 months.

Unusually stable helical kink in the antimicrobial peptide--a derivative of gaegurin

The structure of an active analog of the antibacterial peptide gaegurin was investigated by CD and NMR spectroscopy. The NOE connectivities showed that 21 out of 24 residues formed an a-helix despite the presence of a central proline. CD and NMR analysis indicates that the helix is in fast equilibrium with random coil. From chemical shift analysis of the amide protons, the distances of hydrogen bonding in the helix were calculated, and manifested obvious periodicity which implied a kink in the middle of the helix. 1D amide proton exchange experiments provided further evidence of an exceptionally stable kink. It is inferred that this kink is important not only to the function of the peptide but also to the early stage of the folding as a nucleation site.

Synthesis and antimicrobial activity of squalamine analogue

Synthesis and antimicrobial activity of squalamine analogue 2 are reported. The synthesis of 2 was accomplished from bisnoralcohol 3. The spermidine moiety was introduced via reductive amination of an appropriately functionalized 3beta-aminosterol with spermidinyl aldehyde 17 utilizing sodium triacetoxyborohydride as the reducing agent. Compound 2 shows weaker antimicrobial activity than squalamine.

Structural and functional implications of a proline residue in the antimicrobial peptide gaegurin

Although it is commonly known as a helix breaker, proline residues have been found in the alpha-helical regions of many peptides and proteins. The antimicrobial peptide gaegurin displays alpha-helical structure and has a central proline residue (P14). The structure and activity of gaegurin and its alanine derivative (P14A) were determined by various spectroscopic methods, restrained molecular dynamics, and biological assays. Both P14 and P14A exhibited cooperative helix formation in solution, but the helical stability of P14 was reduced substantially when compared to that of P14A. Chemical-shift analysis indicated that both of the peptides formed curved helices and that P14 showed diminished stability in the region around the central proline. However, hydrogen-exchange data revealed remarkable differences in the location of stable amide protons. P14 showed a stable region in the concave side of the curved helix, while P14A exhibited a stable region in the central turn of the helix. The model structure of P14 exhibited a pronounced kink, in contrast to the uniform helix of P14A. Both peptides showed comparable binding affinities for negatively charged lipids, while P14 had a considerably reduced affinity for a neutral lipid. With its destabilized alpha-helix, P14 exhibited greater antibacterial activity than did P14A. Hence, electrostatic interaction between helical peptides and lipid membranes is believed to be the dominant factor for antibacterial activity. Moreover, helical stability can modulate peptide binding to membranes that is driven by electrostatic interactions. The observation that P14 is a more potent antibacterial agent than P14A implies that the helical kink of P14 plays an important role in the disruption of bacterial membranes.

High-resolution 3D MR imaging of the trochlear nerve

BACKGROUND AND PURPOSE

The cisternal segment of the trochlear nerve is difficult to identify reliably by routine MR imaging. We investigated the visibility and anatomic features of the trochlear nerve by using high-resolution 3D-bTFE imaging in healthy subjects.

MATERIALS AND METHODS

This study was conducted with 32 healthy subjects without ocular movement disorders. For us to visualize the cisternal segment of the trochlear nerve, all subjects underwent 3D-bTFE imaging at 3T with 2 different resolutions: conventional resolution (voxel size, 0.67 x 0.45 x 1.4 mm) and high resolution (voxel size, 0.3 x 0.3 x 0.25 mm). Visibility of the trochlear nerve was graded with the use of a qualitative scale of certainty as follows: definite, probable, and indeterminate. The diameter of the trochlear nerve was measured.

RESULTS

On conventional-resolution images, the visibility of the trochlear nerve was definite in 3 nerves, probable in 12 nerves, and indeterminate in 49 nerves. On high-resolution images, visibility was definite in 63 nerves and probable in 1 nerve. The mean diameter of the trochlear nerve was 0.54 mm (range, 0.35-0.96 mm).

CONCLUSIONS

The trochlear nerve was visualized 100% of the time on high-resolution imaging with a voxel smaller than the nerve diameter. High-resolution imaging should have an important role in investigating the pathogenic mechanism of neuropathic strabismus, such as congenital superior oblique palsy.

Cross sections and transverse single-spin asymmetries in forward neutral-pion production from proton collisions at sqrt[s]=200 GeV

Measurements of the production of forward high-energy pi(0) mesons from transversely polarized proton collisions at sqrt[s]=200 GeV are reported. The cross section is generally consistent with next-to-leading order perturbative QCD calculations. The analyzing power is small at x(F) below about 0.3, and becomes positive and large at higher x(F), similar to the trend in data at sqrt[s]< or =20 GeV. The analyzing power is in qualitative agreement with perturbative QCD model expectations. This is the first significant spin result seen for particles produced with p(T)>1 GeV/c at a polarized proton collider.