357 research outputs found
Hypoxia-inducible factor-1α regulates matrix metalloproteinase-1 activity in human bone marrow-derived mesenchymal stem cells
AbstractWe examined the mRNA levels of hypoxia-inducible factor-1α (HIF-1α) in bone marrow mesenchymal stem cells (bmMSCs) of eight osteoarthritis patients. BmMSC-1, expressing higher HIF-1α mRNA and protein than bmMSC-5, elicited higher matrix metalloproteinase-1 (MMP1) activity and stronger invasive capacity. In vitro invasion assays and quantitative PCR analyses showed that targeted inhibition of HIF-1α in bmMSC-1 decreased its invasion and expressions of MMP1 and MMP3, whereas overexpression of HIF-1α in bmMSC-5 increased its invasion and expressions of MMP1 and MMP3. Therefore, HIF-1α can regulate MMP1 and MMP3 expressions in human bmMSCs, which might suggest a pathophysiological role of bmMSC expressing high HIF-1α in bone diseases
Pressure dependence of upper critical fields in FeSe single crystals
We investigate the pressure dependence of the upper critical fields
({\mu}) for FeSe single crystals with pressure up to 2.57 GPa.
The superconducting (SC) properties show a disparate behavior across a critical
pressure where the pressure-induced antiferromagnetic phase coexists with
superconductivity. The magnetoresistance for and is very
different: for , magnetic field induces and enhances a hump in the
resistivity close to the for pressures higher than 1.2 GPa, while it is
absent for . Since the measured {\mu} for FeSe samples is
smaller than the orbital limited upper critical field ()
estimated by the Werthamer Helfand and Hohenberg (WHH) model, the Maki
parameter ({\alpha}) related to Pauli spin-paramagnetic effects is additionally
considered to describe the temperature dependence of {\mu}().
Interestingly, the {\alpha} value is hardly affected by pressure for ,
while it strongly increases with pressure for . The pressure evolution of
the {\mu}(0)s for the FeSe single crystals is found to be almost
similar to that of (), suggesting that the pressure-induced magnetic
order adversely affects the upper critical fields as well as the SC transition
temperature.Comment: 23 pages, 6 figures, 1 tabl
Targeted profiling of chlorinated transformation products and the parent micropollutants in the aquatic environment: A comparison between two coastal cities
This study investigated chlorinated transformation products (TPs) and their parent micropollutants, aromatic pharmaceuticals and personal care products (PPCPs) in the urban water bodies of two metropolitan cities. Nine PPCPs and 16 TPs were quantitatively or semi-quantitatively determined using isotope dilution techniques and liquid chromatography-tandem mass spectrometry. TPs and most PPCPs were effectively removed by conventional wastewater treatments in a wastewater treatment plant (WWTP). Chlorinated parabens and all PPCPs (at concentrations below 1000 ng/L) were present in the waters receiving treated wastewater. By contrast, the waters receiving untreated wastewater contained higher levels of PPCPs (up to 9400 ng/L) and more species of chlorinated TPs including chlorinated parabens, triclosan, diclofenac, and bisphenol A. The very different chemical profiles between the water bodies of the two cities of similar geographical and climatic properties may be attributed to their respective uses of chemicals and policies of wastewater management. No apparent increase in the number of species or abundances of TPs was observed in either the chlorinated wastewater or the seawater rich in halogens. This is the first study to elucidate and compare the profiles of multiple TPs and their parent PPCPs in the water bodies of coastal cities from tropical islands. Our findings suggest that chlorinated derivatives of bisphenol A, diclofenac, triclosan, and parabens in the surface water originate from sources other than wastewater disinfection or marine chlorination. Although further studies are needed to identify the origins, conventional wastewater treatments may protect natural water bodies against contamination by those chlorinated substances
Enhanced critical current density in the pressure-induced magnetic state of the high-temperature superconductor FeSe
We investigate the relation of the critical current density (Jc) and the
remarkably increased superconducting transition temperature (Tc) for the FeSe
single crystals under pressures up to 2.43 GPa, where the Tc is increased by ~8
K/GPa. The critical current density corresponding to the free flux flow is
monotonically enhanced by pressure which is due to the increase in Tc, whereas
the depinning critical current density at which the vortex starts to move is
more influenced by the pressure-induced magnetic state compared to the increase
of Tc. Unlike other high-Tc superconductors, FeSe is not magnetic, but
superconducting at ambient pressure. Above a critical pressure where magnetic
state is induced and coexists with superconductivity, the depinning Jc abruptly
increases even though the increase of the zero-resistivity Tc is negligible,
directly indicating that the flux pinning property compared to the Tc
enhancement is a more crucial factor for an achievement of a large Jc. In
addition, the sharp increase in Jc in the coexisting superconducting phase of
FeSe demonstrates that vortices can be effectively trapped by the competing
antiferromagnetic order, even though its antagonistic nature against
superconductivity is well documented. These results provide new guidance toward
technological applications of high-temperature superconductors.Comment: 24pages, 8 figure
Elevated plasma level of visfatin/pre-b cell colony-enhancing factor in male oral squamous cell carcinoma patients
Objectives: Visfatin, also known as nicotiamide phosphoribosyltransferase or pre-B cell colony enhancing factor,
is a pro-inflammatory cytokine whose serum level is increased in various cancers. In this study, we investigated
whether plasma visfatin levels were altered in patients with oral squamous cell carcinoma (OSCC). The relation
ship between plasma visfatin levels and the pretreatment hematologic profile was also explored.
Study
Design: Plasma visfatin concentrations were measured through ELISA in OSCC patients and control sub-
D
esign: Plasma visfatin concentrations were measured through ELISA in OSCC patients and control sub-
esign: Plasma visfatin concentrations were measured through ELISA in OSCC patients and control sub
jects. A total of 51 patients with OSCC and 57 age- and body mass index (BMI)-matched control subjects were
studied. All study subjects were male.
Results: Plasma visfatin was found to be elevated in patients with OSCC (7.0 ± 4.5 vs. 4.8 ± 1.9 ng/ml, p = 0.002).
Multiple logistic regression analysis revealed visfatin as an independent association factor for OSCC, even after
full adjustment of known biomarkers. Visfatin level was significantly correlated with white blood cell (WBC)
count, neutrophil count, and hematocrit (all p < 0.05). In addition, WBC count, neutrophil count, and visfatin
gradually increased with stage progression, and hematocrit gradually decreased with stage progression (all p <
0.05).
Conclusion: Increased plasma visfatin levels were associated with OSCC, independent of risk factors, and were cor
related with inflammatory biomarkers. These data suggest that visfatin may act through inflammatory reactions to
play an important role in the pathogenesis of OSC
The potential impact of primary headache disorders on stroke risk
Distribution of PHDs. (DOC 55 kb
Association of Suicide Risk With Headache Frequency Among Migraine Patients With and Without Aura
Background: Migraines with aura have been associated with suicide in adolescents and young adults, but the association between suicide and migraine frequency has not been determined. This study investigated suicidal ideation and suicide attempts among patients with varying frequencies of migraines, with and without auras.Methods: This cross-sectional study analyzed 528 patients aged between 20 and 60 years from a headache outpatient clinic in Taiwan. All patients completed a set of questionnaires, including a demographic questionnaire, the Migraine Disability Assessment questionnaire, the Hospital Anxiety and Depression Scale, the Beck Depression Inventory, and the Pittsburgh Sleep Quality Index. Suicide risk was evaluated by self-reported lifetime suicidal ideation and attempts. Patients were divided into low-frequency (1–4 days/month), moderate-frequency (5–8 days/month), high-frequency (9–14 days/month), and chronic (≥15 days/month) migraine groups. The association between migraine frequency and suicidality was investigated using multivariable linear regression and logistic regression.Results: The rates of suicidal ideation and suicide attempts were the highest for chronic migraine with aura (ideation: 47.2%; attempts: 13.9%) and lowest in migraine-free controls (2.8%). Migraine frequency was an independent risk factor for suicidal ideation and attempts in patients with aura (both Ptrend < 0.001), but not in patients without auras. Migraine aura and depression were associated with higher risks of suicidal ideation and suicide attempts in patients with migraine.Conclusion: High migraine frequency has a correlation with high suicide risk in patients who experience an aura, but not in other patients with migraine
Distinct functional defect of three novel Brugada syndrome related cardiac sodium channel mutations
The Brugada syndrome is characterized by ST segment elevation in the right precodial leads V1-V3 on surface ECG accompanied by episodes of ventricular fibrillation causing syncope or even sudden death. The molecular and cellular mechanisms that lead to Brugada syndrome are not yet completely understood. However, SCN5A is the most well known responsible gene that causes Brugada syndrome. Until now, more than a hundred mutations in SCN5A responsible for Brugada syndrome have been described. Functional studies of some of the mutations have been performed and show that a reduction of human cardiac sodium current accounts for the pathogenesis of Brugada syndrome. Here we reported three novel SCN5A mutations identified in patients with Brugada syndrome in Taiwan (p.I848fs, p.R965C, and p.1876insM). Their electrophysiological properties were altered by patch clamp analysis. The p.I848fs mutant generated no sodium current. The p.R965C and p.1876insM mutants produced channels with steady state inactivation shifted to a more negative potential (9.4 mV and 8.5 mV respectively), and slower recovery from inactivation. Besides, the steady state activation of p.1876insM was altered and was shifted to a more positive potential (7.69 mV). In conclusion, the SCN5A channel defect related to Brugada syndrome might be diverse but all resulted in a decrease of sodium current
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