14 research outputs found
Biogenesis of non-structural protein 1 (nsp1) and nsp1-mediated type I interferon modulation in arteriviruses
AbstractType I interferons (IFNs-α/β) play a key role for the antiviral state of host, and the porcine arterivirus; porcine reproductive and respiratory syndrome virus (PRRSV), has been shown to down-regulate the production of IFNs during infection. Non-structural protein (nsp) 1 of PRRSV has been identified as a viral IFN antagonist, and the nsp1α subunit of nsp1 has been shown to degrade the CREB-binding protein (CBP) and to inhibit the formation of enhanceosome thus resulting in the suppression of IFN production. The study was expanded to other member viruses in the family Arteriviridae: equine arteritis virus (EAV), murine lactate dehydrogenase-elevating virus (LDV), and simian hemorrhagic fever virus (SHFV). While PRRSV–nsp1 and LDV–nsp1 were auto-cleaved to produce the nsp1α and nsp1β subunits, EAV–nsp1 remained uncleaved. SHFV–nsp1 was initially predicted to be cleaved to generate three subunits (nsp1α, nsp1β, and nsp1γ), but only two subunits were generated as SHFV–nsp1αβ and SHFV–nsp1γ. The papain-like cysteine protease (PLP) 1α motif in nsp1α remained inactive for SHFV, and only the PLP1β motif of nsp1β was functional to generate SHFV–nsp1γ subunit. All subunits of arterivirus nsp1 were localized in the both nucleus and cytoplasm, but PRRSV–nsp1β, LDV–nsp1β, EAV–nsp1, and SHFV–nsp1γ were predominantly found in the nucleus. All subunits of arterivirus nsp1 contained the IFN suppressive activity and inhibited both interferon regulatory factor 3 (IRF3) and NF-κB mediated IFN promoter activities. Similar to PRRSV–nsp1α, CBP degradation was evident in cells expressing LDV–nsp1α and SHFV–nsp1γ, but no such degradation was observed for EAV–nsp1. Regardless of CBP degradation, all subunits of arterivirus nsp1 suppressed the IFN-sensitive response element (ISRE)-promoter activities. Our data show that the nsp1-mediated IFN modulation is a common strategy for all arteriviruses but their mechanism of action may differ from each other
Triaxial Electrospun Nanofiber Membranes for Controlled Dual Release of Functional Molecules
A novel dual drug delivery system
is presented using triaxial structured nanofibers, which provides
different release profiles for model drugs separately loaded in either
the sheath or the core of the fiber. Homogenous, coaxial and triaxial
fibers containing a combination of materials (PCL, polycaprolactone;
PVP, polyvinylpyrrolidone) were fabricated. The drug release profiles
were simulated using two color dyes (KAB, keyacid blue; KAU, keyacid
uranine), whose release in physiological solution was measured using
optical absorption as a function of time. To reach the level of 80%
release of encapsulated dye from core, triaxial fibers with a PCL
intermediate layer exhibited a ∼24× slower release than
that from coaxial fibers. At the same time, the hygroscopic sheath
layer of the triaxial fibers provided an initial burst release (∼
80% within an hour) of a second dye as high as that from conventional
single and coaxial fibers. The triaxial fiber membrane provides both
a quick release from the outer sheath layer for short-term treatment
and a sustained release from the fiber core for long-term treatment.
The intermediate layer between inner core and outer sheath acts as
a barrier to prevent leaching from the core, which can be especially
important when the membranes are used in wet application. The formation
of tri/multiaxially electrospun nanofibrous membranes will be greatly
beneficial for biomedical applications by enabling different release
profiles of two different drugs from a membrane
Selective pH-Responsive Core–Sheath Nanofiber Membranes for Chem/Bio/Med Applications: Targeted Delivery of Functional Molecules
Core–sheath
fibers using different Eudragit materials were successfully produced,
and their controlled multi-pH responses have been demonstrated. Core–sheath
fibers made of Eudragit L 100 (EL100) core and Eudragit S 100 (ES100)
sheath provide protection and/or controlled release of core material
at pH 6 by adjusting the sheath thickness (controlled by the flow
rate of source polymer solution). The thickest sheath (∼250
nm) provides the least core release ∼1.25%/h, while the thinnest
sheath (∼140 nm) provides much quicker release ∼16.75%/h.
Furthermore, switching core and sheath material dramatically altered
the pH response. Core–sheath fibers made of ES100 core and
EL100 sheath can provide a consistent core release rate, while the
sheath release rate becomes higher as the sheath layer becomes thinner.
For example, the thinnest sheath (∼120 nm) provides a core
and sheath release ratio of 1:2.5, while the thickest sheath (∼200
nm) shows only a ratio of 1:1.7. All core–sheath Eudragit fibers
show no noticeable release at pH 5, while they are completely dissolved
at pH 7. Extremely high surface area in the porous network of the
fiber membranes provides much faster (>30 times) response to external
pH changes as compared to that of equivalent cast films
Influence of Different Oligosaccharides and Inulin on Heterocyclic Aromatic Amine Formation and Overall Mutagenicity in Fried Ground Beef Patties
Absorption of Ethylene on Membranes Containing Potassium Permanganate Loaded into Alumina-Nanoparticle-Incorporated Alumina/Carbon Nanofibers
Ethylene is a natural
aging hormone in plants, and controlling
its concentration has long been a subject of research aimed at reducing
wastage during packaging, transport, and storage. We report on packaging
membranes, produced by electrospinning, that act as efficient carriers
for potassium permanganate (PPM), a widely used ethylene oxidant.
PPM salt loaded on membranes composed of alumina nanofibers incorporating
alumina nanoparticles outperform other absorber systems and oxidize
up to 73% of ethylene within 25 min. Membrane absorption of ethylene
generated by avocados was totally quenched in 21 h, and a nearly zero
ethylene concentration was observed for more than 5 days. By comparison,
the control experiments exhibited a concentration of 53% of the initial
value after 21 h and 31% on day 5. A high surface area of the alumina
nanofiber membranes provides high capacity for ethylene absorption
over a long period of time. In combination with other properties,
such as planar form, flexibility, ease of handling, and lightweight,
these membranes are a highly desirable component of packaging materials
engineered to enhance product lifetime
Stimuli-Responsive Self-Immolative Polymer Nanofiber Membranes Formed by Coaxial Electrospinning
The first self-immolative
polymer (SIP) nanofiber membrane is demonstrated
in this report, in which the immolation can be triggered by external
stimulus. Electrospun SIP/polyacrylonitrile (PAN) fibers provide depolymerization
that is ∼25 times quicker and more responsive (i.e., immolation)
than that of a cast film in the triggering condition. Depolymerization
of SIP in the SIP/PAN blended fiber membrane results in the transition
of the surface properties from hydrophobic (∼110°) to
hygroscopic (∼0°). Triggered release of encapsulated functional
molecules was demonstrated using coaxially electrospun fiber membrane
made of a SIP/PAN blend sheath and polyvinylpyrrolidone/dye core.
Coaxial fibers with the SIP/PAN sheath provide minimal release of
the encapsulated material in nontriggering solution, while it releases
the encapsulated material instantly when the triggering condition
is met. Its versatility has been strengthened compared to that of
non-SIP coaxial fibers that provide no triggering reaction by external
stimulus
Interaction Effect of Phase Angle and Age on Femoral Neck Bone Mineral Density in Patients with Non-Dialysis Chronic Kidney Disease Stage 5
Background: Low bone mass is common in malnourished patients with chronic kidney disease (CKD) and can lead to a higher risk of fractures. Elderly and CKD patients have the same risk factors for protein-energy wasting, sarcopenia, and osteoporosis. Here, we investigated the association between phase angle (PhA) and bone mineral density (BMD) in dialysis-naïve patients with CKD stage 5 (CKD5) and identified a statistical relationship between PhA and age, which affects bone density. Methods: Bio-impedance spectroscopy for evaluating body composition and PhA and dual-energy X-ray absorptiometry for determining the BMD were simultaneously performed in 167 consecutive patients (mean age, 59.65 ± 13.98 years; women, 40.1%). Two-way analysis of variance (ANOVA) was conducted to assess the potential interaction effect of PhA and age on femoral neck BMD (FN-BMD). Results: Our results showed that PhA and age were independently associated with FN-BMD and T-score in multiple linear regressions analyses. A significant interaction effect of PhA and age on FN-BMD was found on two-way ANOVA (p = 0.028). The average BMD values for the first and second tertiles of the PhA were higher in the young versus elderly group, whereas patients in the elderly group had higher BMD in the third tertiles. Conclusions: A relationship was noted between PhA and BMD in patients with advanced-stage CKD. The effect of PhA level on FN-BMD differed between elderly and young patients. Our study suggested that higher PhA levels could be a marker explaining the maintenance of good bone health in elderly patients with CKD5. Further longitudinal analyses are needed to determine whether PhA predicts the risk of CKD-MBD-related fractures during CKD progression
Moderating Effect of the Lean Tissue Index on the Relationship between the Trabecular Bone Score and Augmentation Index in Dialysis Naïve Patients with Stage 5 Chronic Kidney Disease
Osteopenia, sarcopenia, and increased vascular stiffness are common in patients with chronic kidney disease-mineral bone disorder (CKD-MBD) with protein energy wasting and can lead to worse clinical outcomes. We investigated the potential moderating role of the lean tissue index (LTI) in the relationship between bone microarchitecture and vascular stiffness in dialysis naïve patients with stage 5 CKD. Bioimpedance spectroscopy for evaluating LTI, lumbar spine dual energy X-ray absorptiometry for determining the trabecular bone score (TBS), and arterial applanation tonometry measurements for the central augmentation index, at a heart rate of 75 beats/minute (cAIx75), were simultaneously performed in 117 consecutive patients. A hierarchical regression analysis was conducted to assess the moderating effect of LTI on the relationship between TBS and cAIx75 after adjusting for age and sex. The effect of the interaction between LTI and TBS on cAIx75 was statistically significant (p = 0.030), demonstrating that the cAIx75 tends to decrease more, with the joint effect of LTI and TBS. In the separate analyses, the interaction effect was significant only in women (p = 0.048) and the group of diabetes (p = 0.042). Our study suggests that the evaluation of changes in body composition, bone health, and vascular stiffness needs to be performed simultaneously in patients with advanced-stage CKD. Further research in patients with different stages of CKD warranted to generalize and apply our results to patients in other stages
Electrospun Carbon Nanofiber Modified Electrodes for Stripping Voltammetry
Electrospun
polyacrylonitrile (PAN) based carbon nanofibers (CNFs)
have attracted intense attention due to their easy processing, high
carbon yield, and robust mechanical properties. In this work, a CNF
modified glassy carbon (GC) electrode that was coated with Nafion
polymer was evaluated as a new electrode material for the simultaneous
determination of trace levels of heavy metal ions by anodic stripping
voltammetry (ASV). Pb<sup>2+</sup> and Cd<sup>2+</sup> were used as
a representative system for this initial study. Well-defined stripping
voltammograms were obtained when Pb<sup>2+</sup> and Cd<sup>2+</sup> were determined individually and then simultaneously in a mixture.
Compared to a bare GC electrode, the CNF/Nafion modified GC (CNF/Nafion/GC)
electrode improved the sensitivity for lead detection by 8-fold. The
interface properties of the CNF/Nafion/GC were characterized by electrochemical
impedance spectroscopy (EIS), which showed the importance of the ratio
of CNF/Nafion on electrode performance. Under optimized conditions,
the detection limits are 0.9 and 1.5 nM for Pb<sup>2+</sup> and Cd<sup>2+</sup>, respectively