2,523 research outputs found

    Direct Separation of Short Range Order in Intermixed Nanocrystalline and Amorphous Phases

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    Diffraction anomalous fine-structure (DAFS) and extended x-ray absorption fine-structure (EXAFS) measurements were combined to determine short range order (SRO) about a single atomic type in a sample of mixed amorphous and nanocrystalline phases of germanium. EXAFS yields information about the SRO of all Ge atoms in the sample, while DAFS determines the SRO of only the ordered fraction. We determine that the first-shell distance distribution is bimodal; the nanocrystalline distance is the same as the bulk crystal, to within 0.01(2)   Å, but the mean amorphous Ge-Ge bond length is expanded by 0.076(19)   Å. This approach can be applied to many systems of mixed amorphous and nanocrystalline phases

    Gene transfer of GLT-1, a glial glutamate transporter, into the spinal cord by recombinant adenovirus attenuates inflammatory and neuropathic pain in rats

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    <p>Abstract</p> <p>Background</p> <p>The glial glutamate transporter GLT-1 is abundantly expressed in astrocytes and is crucial for glutamate removal from the synaptic cleft. Decreases in glutamate uptake activity and expression of spinal glutamate transporters are reported in animal models of pathological pain. However, the lack of available specific inhibitors and/or activators for GLT-1 makes it difficult to determine the roles of spinal GLT-1 in inflammatory and neuropathic pain. In this study, we examined the effect of gene transfer of GLT-1 into the spinal cord with recombinant adenoviruses on the inflammatory and neuropathic pain in rats.</p> <p>Results</p> <p>Intraspinal infusion of adenoviral vectors expressing the GLT-1 gene increased GLT-1 expression in the spinal cord 2–21 days after the infusion. Transgene expression was primarily localized to astrocytes. The spinal GLT-1 gene transfer had no effect on acute mechanical and thermal nociceptive responses in naive rats, whereas it significantly reduced the inflammatory mechanical hyperalgesia induced by hindlimb intraplantar injection of carrageenan/kaolin. Spinal GLT-1 gene transfer 7 days before partial sciatic nerve ligation recovered the extent of the spinal GLT-1 expression in the membrane fraction that was decreased following the nerve ligation, and prevented the induction of tactile allodynia. However, the partial sciatic nerve ligation-induced allodynia was not reversed when the adenoviruses were infused 7 or 14 days after the nerve ligation.</p> <p>Conclusion</p> <p>These results suggest that overexpression of GLT-1 on astrocytes in the spinal cord by recombinant adenoviruses attenuates the induction, but not maintenance, of inflammatory and neuropathic pain, probably by preventing the induction of central sensitization, without affecting acute pain sensation. Upregulation or functional enhancement of spinal GLT-1 could be a novel strategy for the prevention of pathological pain.</p

    Impact of Short-Term Training Camp on Aortic Blood Pressure in Collegiate Endurance Runners

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    To investigate the influence of short-term vigorous endurance training on aortic blood pressure (BP), pulse wave analysis was performed in 36 highly trained elite collegiate endurance runners before and after a 7-day intense training camp. Subjects participated three training sessions per day, which mainly consisted of long distance running and sprint training to reach the daily target distance of 26 km. After the camp, they were divided into two groups based on whether the target training was achieved. Aortic systolic BP, pulse pressure, and tension-time index (TTI, a surrogate index of the myocardial oxygen demand) were significantly elevated after the camp in the accomplished group but not in the unaccomplished group, whereas the brachial BP remained unchanged in both groups. The average daily training distance was significantly correlated with the changes in aortic systolic BP (r = 0.608, p = 0.0002), pulse pressure (r = 0.415, p = 0.016), and TTI (r = 0.438, p = 0.011). These results suggest that aortic BP is affected by a short-term vigorous training camp even in highly trained elite endurance athletes presumably due to a greater training volume compared to usual

    Hypernova Nucleosynthesis and Galactic Chemical Evolution

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    We study nucleosynthesis in 'hypernovae', i.e., supernovae with very large explosion energies ( \gsim 10^{52} ergs) for both spherical and aspherical explosions. The hypernova yields compared to those of ordinary core-collapse supernovae show the following characteristics: 1) Complete Si-burning takes place in more extended region, so that the mass ratio between the complete and incomplete Si burning regions is generally larger in hypernovae than normal supernovae. As a result, higher energy explosions tend to produce larger [(Zn, Co)/Fe], small [(Mn, Cr)/Fe], and larger [Fe/O], which could explain the trend observed in very metal-poor stars. 2) Si-burning takes place in lower density regions, so that the effects of α\alpha-rich freezeout is enhanced. Thus 44^{44}Ca, 48^{48}Ti, and 64^{64}Zn are produced more abundantly than in normal supernovae. The large [(Ti, Zn)/Fe] ratios observed in very metal poor stars strongly suggest a significant contribution of hypernovae. 3) Oxygen burning also takes place in more extended regions for the larger explosion energy. Then a larger amount of Si, S, Ar, and Ca ("Si") are synthesized, which makes the "Si"/O ratio larger. The abundance pattern of the starburst galaxy M82 may be attributed to hypernova explosions. Asphericity in the explosions strengthens the nucleosynthesis properties of hypernovae except for "Si"/O. We thus suggest that hypernovae make important contribution to the early Galactic (and cosmic) chemical evolution.Comment: To be published in "The Influence of Binaries on Stellar Population Studies", ed. D. Vanbeveren (Kluwer), 200

    Increased IP-10 production by blood–nerve barrier in multifocal acquired demyelinating sensory and motor neuropathy and multifocal motor neuropathy

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    Objective Dysfunction of the blood–nerve barrier (BNB) plays important roles in chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN). The aim of the present study was to identify the candidate cytokines/chemokines that cause the breakdown of the BNB using sera from patients with CIDP and MMN. Methods We determined the levels of 27 cytokines and chemokines in human peripheral nerve microvascular endothelial cells (PnMECs) after exposure to sera obtained from patients with CIDP variants (typical CIDP and multifocal acquired demyelinating sensory and motor neuropathy [MADSAM]), MMN and amyotrophic lateral sclerosis (ALS), and healthy controls (HC), using a multiplexed fluorescent bead-based immunoassay system. Results The induced protein (IP)10 level in the cells in both the MADSAM and MMN groups was markedly increased in comparison with the typical CIDP, ALS and HC groups. The other cytokines, including granulocyte colony-stimulating factor, vascular endothelial growth factor (VEGF) and interleukin-7, were also significantly upregulated in the MADSAM group. The increase of IP-10 produced by PnMECs was correlated with the presence of conduction block in both the MADSAM and MMN groups. Conclusion The autocrine secretion of IP-10 induced by patient sera in PnMECs was markedly upregulated in both the MADSAM and MMN groups. The overproduction of IP-10 by PnMECs leads to the focal breakdown of the BNB and may help to mediate the transfer of pathogenic T cells across the BNB, thereby resulting in the appearance of conduction block in electrophysiological studies of patients with MADSAM and MMN

    'Special K' and a loss of cell-to-cell adhesion in proximal tubule-derived epithelial cells: modulation of the adherens junction complex by ketamine

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    Ketamine, a mild hallucinogenic class C drug, is the fastest growing ‘party drug’ used by 16–24 year olds in the UK. As the recreational use of Ketamine increases we are beginning to see the signs of major renal and bladder complications. To date however, we know nothing of a role for Ketamine in modulating both structure and function of the human renal proximal tubule. In the current study we have used an established model cell line for human epithelial cells of the proximal tubule (HK2) to demonstrate that Ketamine evokes early changes in expression of proteins central to the adherens junction complex. Furthermore we use AFM single-cell force spectroscopy to assess if these changes functionally uncouple cells of the proximal tubule ahead of any overt loss in epithelial cell function. Our data suggests that Ketamine (24–48 hrs) produces gross changes in cell morphology and cytoskeletal architecture towards a fibrotic phenotype. These physical changes matched the concentration-dependent (0.1–1 mg/mL) cytotoxic effect of Ketamine and reflect a loss in expression of the key adherens junction proteins epithelial (E)- and neural (N)-cadherin and β-catenin. Down-regulation of protein expression does not involve the pro-fibrotic cytokine TGFβ, nor is it regulated by the usual increase in expression of Slug or Snail, the transcriptional regulators for E-cadherin. However, the loss in E-cadherin can be partially rescued pharmacologically by blocking p38 MAPK using SB203580. These data provide compelling evidence that Ketamine alters epithelial cell-to-cell adhesion and cell-coupling in the proximal kidney via a non-classical pro-fibrotic mechanism and the data provides the first indication that this illicit substance can have major implications on renal function. Understanding Ketamine-induced renal pathology may identify targets for future therapeutic intervention

    Clinical significance of vascular endothelial growth factor and Delta-like ligand 4 in small pulmonary adenocarcinoma

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    Vascular endothelial growth factor (VEGF) plays a key role in tumor angiogenesis. The notch ligand Delta-like ligand 4 (DLL4) is induced by VEGF and acts as a negative regulator of tumor angiogenesis by reducing the numbers of non-productive sprouting vessels. Several reports have shown the prognostic role of VEGF expression in non-small cell lung cancer. However, the correlation between VEGF and DLL4 expression and their clinical significance in non-small cell lung cancer remains unclear. The aim of this study was to analyze the correlation between the expression of VEGF/DLL4 and the clinicopathological background. Fifty-eight patients with lung adenocarcinomas measuring less than 3 cm in diameter who underwent surgical resection at Kawasaki Medical School Hospital from 2008 to 2010 were enrolled in this study. The expressions of VEGF, DLL4, CD31, and Ki-67 were analyzed using immunohistochemical staining. The tumor cells were VEGF-positive in 44 patients (75.9%) and DLL4-positive in 41 patients (70.7%). No statistically significant association was observed between the patients\u27 characteristics and VEGF/DLL4 expression. A high VEGF expression level tended to be associated with a high DLL4 expression level (P = 0.050, r = 0.258). The mean Ki-67 index was significantly lower in the patients with high VEGF expression (9.5 vs. 18.2, P = 0.011), but no significant difference was observed when patients were compared according to their DLL4 expression levels (11.8 vs. 11.0, P = 0.804). The mean Ki-67 index was higher in the VEGF_ DLL4_ patients than in the VEGFhigh DLL4high patients by a marginally significant difference (20.1 vs. 10.9 P = 0.056). The 3-year recurrence-free survival rates of the VEGF_/DLL4_ and the VEGF_/DLL4_ patients were 83.3% and 35.7%, respectively. The prognosis of the VEGF_/DLL4_ patients was significantly better than that of the VEGF_/DLL4_ patients (P = 0.032). To investigate the significance of the difference in tumor proliferation and prognosis between the VEGF_/DLL4_ and the VEGF_/DLL4_ patients, we evaluated the morphologic effect of VEGF/DLL4 expression on the intratumoral capillaries by counting the number of capillaries and calculating the luminal area (μm^2). No significant differences were seen between either the VEGF or DLL4 expression levels and the mean number of intratumoral capillaries or the luminal area (μm^2). In conclusion, VEGF_/DLL4_ patients with small pulmonary adenocarcinoma had a significantly poorer prognosis, although no significant difference in a morphological evaluation of the capillaries was seen between VEGF_/DLL4_ and VEGF_/DLL4_ patients

    Cd, Hg, Pb, and As in European species of wild growing forest landscape fungi : a review

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    Kadmij (Cd), živo srebro (Hg), svinec (Pb) in arzen (As) so kovine, ki se naravno ali kot posledica človekove dejavnosti pojavljajo v okolju, tudi v gozdni krajini, kjer so rastišča številnih evropskih vrst gliv. Namen članka je bil pripraviti pregled vrst in količin izbranih kovin v trosnjakih gliv terprimerjati lastne raziskave, opravljene v različno onesnaženih območjih v Sloveniji (Zgornja Mežiška, Šaleška in Poljanska dolina), s podatki evropskih raziskav. Vsebnosti kovin v trosnjakih gliv iz neonesnaženih območij pravilomanajdemo v naslednjih intervalih: <0,5 mg/kg suhe teže (Cd), < 0,5 mg/kg do 10 mg/kg suhe teže (Hg), < 0,5 mg/kg do 5 mg/kg suhe teže (Pb) in < 0,5 mg/kg do 1 (2) mg/kg suhe teže (As). Na podlagi pregleda vsebnosti izbranih kovin v trosnjakih gliv ugotavljamo, da sta problematični kovini predvsem Cd in Hg. Omenjeni kovini lahko dosegata velike vsebnosti celo v glivah, ki rastejo v neonesnaženih območjih. Za vse analizirane kovin je značilno, da v trosnjakih gliv iz močno onesnaženih območji dosegajo velike, celo ekstemne vsebnosti, ki nekajkrat prekoračujejo vsebnosti iz neonesnaženih območij. Upoštevaje primerjavo z evropskimi raziskavami ugotavljamo, da je Zgornja Mežiška dolina obremenjena s Pb in Cd, Šaleška dolina pa s Cd in As.Metals, which originate from anthropogenic and natural activities, frequently occur in forest landscape with habitats of many European species of wild growing fungi. The presented review focuses on cadmium (Cd), mercury (Hg), lead (Pb), and arsenic (As) levels in fruiting bodies of wild growing European species of fungi of forest landscape. Furthermore, a comparison with studies of this kind performed in Slovenia was made with the aim to assess themetals levels in fungi from differently polluted areas in Slovenia (the Upper Meža Valley, the Šalek Valley, the Poljana Valley). The usual reported levels for most species grown in unpolluted areas are in the following ranges:Cd: < 0,5 mg/kg - 5 mg/kg dry weight (dw), Hg: < 0,5 mg/kg - 10 mg/kg dw, Pb: < 0,5 mg/kg - 5 mg/kg dw, As: < 0,5 mg/kg -1 (2) mg/kg dw (As), respectively. The presented data reveal that cadmium (Cd) and mercury (Hg) have probably been the most detrimental trace elements in fruiting bodies, which can reach increased levels even in unpolluted areas. It is evident for all analyzed trace elements that values can considerably increase in fungi picked in severely polluted areas. According to data regarding Slovene studies and comparison with other European studies, it is obvious that the Šalek Valley is enriched with Cd and As, while the Upper Meža Valley is considerably polluted with Pb and Cd
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