In Vivo Hepatoprotective Effects of a Peptide Fraction from Krill Protein Hydrolysates against Alcohol-Induced Oxidative Damage.

BACKGROUND: Krill (Euphausia superba) represent the largest animal biomass on earth, and are a rich source of high-quality protein with essential amino acids. Krill-derived peptides are renowned for their antioxidant activities. Hence, these peptides may have protective effects against oxidative stress. Alcoholic liver disease is a prevalent cause of death worldwide. The present study explores the hepatoprotective effects of krill peptide hydrolysate fractions against ethanol-induced liver damage in BALB/c mice. METHODS: Hydrolysis was carried out by mimicking the gastrointestinal digestion environment and the filtrate was fractionated based on molecular weight (<1 kDa, 1-3 kDa, and >3 kDa). The 1-3 kDa fraction (KPF), which indicated the highest antioxidant effect, was further investigated for its effect on weight and survival rate increase in mice and its influence on serum glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, and liver cholesterol levels. Moreover, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) levels were measured, followed by Nrf2 and HO-1 expression. Histopathology studies were conducted to assess hepatic tissue damage. RESULTS: KPF enhanced the weight and survival rate of mice while reducing serum glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, and liver cholesterol levels. Moreover, KPF upregulated SOD, CAT, and GPx in liver tissues, while downregulating tumor necrosis factor α and interleukin-6 mRNA expression. KPF further increased Nrf2 and HO-1 expression and suppressed ethanol-induced apoptotic proteins in the liver. Histopathology of KPF-treated mice showed less hepatic tissue damage compared to ethanol-treated mice. CONCLUSIONS: Hydrolysates and bioactive peptides prepared from krill can be employed as functional foods to enhance liver function and health. Further investigations of KPF could lead to the development of functional foods.

Free-Standing Graphene Thermophone on a Polymer-Mesh Substrate.

A graphene thermoacoustic loudspeaker with a thin polymer mesh is fabricated using screen-printing. An experiment with substrates of various free-standing areas shows that a higher sound pressure level can be achieved as compared to previously reported graphene thermoacoustic loudspeakers. Moreover, a modified equation to predict the sound pressure level of the thermoacoustic loudspeaker with a thin and patterned substrate is proposed and verified by experimental results.

ß-arrestins and G protein-coupled receptor trafficking.

Nonvisual arrestins (ß-arrestin-1 and ß-arrestin-2) are adaptor proteins that function to regulate G protein-coupled receptor (GPCR) signaling and trafficking. ß-arrestins are ubiquitously expressed and function to inhibit GPCR/G protein coupling, a process called desensitization, and promote GPCR trafficking and arrestin-mediated signaling. ß-arrestin-mediated endocytosis of GPCRs requires the coordinated interaction of ß-arrestins with clathrin, adaptor protein 2 (AP2), and phosphoinositides. These interactions are facilitated by a conformational change in ß-arrestin that is thought to occur upon binding to a phosphorylated activated GPCR. In this review, we provide an overview of the key interactions involved in ß-arrestin-mediated trafficking of GPCRs.

Beta-arrestin1 phosphorylation by GRK5 regulates G protein-independent 5-HT4 receptor signalling.

G protein-coupled receptors (GPCRs) have been found to trigger G protein-independent signalling. However, the regulation of G protein-independent pathways, especially their desensitization, is poorly characterized. Here, we show that the G protein-independent 5-HT(4) receptor (5-HT(4)R)-operated Src/ERK (extracellular signal-regulated kinase) pathway, but not the G(s) pathway, is inhibited by GPCR kinase 5 (GRK5), physically associated with the proximal region of receptor' C-terminus in both human embryonic kidney (HEK)-293 cells and colliculi neurons. This inhibition required two sequences of events: the association of beta-arrestin1 to a phosphorylated serine/threonine cluster located within the receptor C-t domain and the phosphorylation, by GRK5, of beta-arrestin1 (at Ser(412)) bound to the receptor. Phosphorylated beta-arrestin1 in turn prevented activation of Src constitutively bound to 5-HT(4)Rs, a necessary step in receptor-stimulated ERK signalling. This is the first demonstration that beta-arrestin1 phosphorylation by GRK5 regulates G protein-independent signalling.

Coloration on Bluish Alginate Films with Amorphous Heterogeneity Thereof.

Using sodium alginate (Alg) aqueous solution containing indigo carmine (IdC) at various concentrations we characterized the rippled surface pattern with micro-spacing on a flexible film as intriguing bluish Alg-IdC iridescence. The characterization was performed using Fourier-transform infrared spectroscopy, ultraviolet-visible spectroscopy, field emission scanning electron microscopy, atomic force microscopy, electron microscopy, differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction analysis, and photoluminescence detection. The edge pattern on the film had a maximum depth of 825 nm, a peak-to-peak distance of 63.0 nm, and an average distance of 2.34 nm. The center of the pattern had a maximum depth of 343 nm and a peak-to-peak distance of 162 nm. The pattern spacing rippled irregularly, widening toward the center and narrowing toward the edges. The rippled nano-patterned areas effectively generated iridescence. The ultraviolet absorption spectra of the mixture in the 270 and 615 nm ranges were the same for both the iridescent and non-iridescent film surfaces. By adding Ag+ ions to Alg-IdC, self-assembled microspheres were formed, and conductivity was improved. Cross-linked bluish materials were immediately formed by the addition of Ca2+ ions, and the film was prepared by controlling their concentration. This flexible film can be used in applications such as eco-friendly camouflage, anti-counterfeiting, QR code materials for imaging/sensing, and smart hybrid displays.

Fabrication of innocuous hydrogel scaffolds based on modified dextran for biotissues.

Substrates with basic structures similar to those of living tissues are useful as cellular scaffolds for the preparation of biocompatible and innocuous materials. In this study, a hydrogel matrix was prepared by introducing a functional group capable of forming crosslinks between natural polymers to create a basis for preparing a microenvironment favorable for cell adaptation. The modified dextran hydrogel polymer was designed to mimic the conditions of the extracellular matrix (ECM) as a scaffold. The precursors of the target hydrogel were synthesized using condensation with a stepwise procedure. A delicate hydrogel based on modified dextran was obtained via photo-crosslinking under room temperature at UV-254 nm. The biocompatibility of this hydrogel was verified using green fluorescence images acquired by incubating a cell line. The characteristics of the hydrogel were verified using proton nuclear magnetic resonance (1H NMR), Fourier-transform infrared (FT-IR) spectroscopy, field-emission scanning electron microscopy (FE-SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD) analysis, and electrostatic spinning. The crosslinked structure and biocompatibility of the modified hydrogel were confirmed using instrumental analyses and a promising cell culture. Using TGA, the weight losses of precursor and hydrogel were determined to be 90.96% and 39.2%, respectively, up to 600 °C. The diameters of the nanofibers, fabricated via electrospinning, were measured to range from 200 to 500 nm.

Controllable Triboelectric Series Using Gradient Positive and Negative Charge-Confinement Layer with Different Particle Sizes of Mesoporous Carbon Materials.

As a method to maximize the energy efficiency of triboelectric nanogenerators (TENGs), high-voltage charge injection (HVCI) on the surface is a simple and effective method for increasing surface charge densities. In this study, positive and negative triboelectric series are controlled using a 3-layer gradient charge-confinement wherein the particle sizes of the mesoporous carbon spheres (mCSs) are sequentially arranged depending on the external surface area of the mCSs. In the gradient charge-confinement layers of this study, the mCS with different sizes perform charge transport from the surface to a deep position during HVCI while mitigating the charge loss through charge confinement to induce the high space charge densities. Through this process, the output voltage-which is initially 15.2 V-is measured to be 600 V after HVCI, thus representing an increase of about 40 times. Further, to amplify the low output current, which is a disadvantage of triboelectric energy, two types of electrical energy-triboelectric and electromagnetic energy-are produced in single mechanical motion. As a result, the output current produced by the cylindrical TENG and electromagnetic generator is recorded as being 1300 times higher, increasing from 12.8 µA to 17.5 mA.

Non-visual arrestins are constitutively associated with the centrosome and regulate centrosome function.

In addition to regulating receptor activity, non-visual arrestins function as scaffolds for numerous intracellular signaling cascades and as regulators of gene transcription. Here we report that the two non-visual arrestins, arrestin2 and arrestin3, localize to the centrosome, a key organelle involved in microtubule nucleation and bipolar mitotic spindle assembly. Both arrestins co-localized with the centrosomal marker gamma-tubulin during interphase and mitosis and were found in purified centrosome preparations. In vitro binding assays demonstrated that both arrestins directly interact with gamma-tubulin. Knockdown of either arrestin by RNA interference resulted in multinucleation, centrosome amplification, and mitotic defects, although only the loss of arrestin2 triggered aberrant microtubule nucleation. Importantly, overexpression of wild type arrestin rescued the multinucleation phenotype and restored normal centrosome number in arrestin siRNA-transfected cells. Moreover, overexpression of arrestin2 or -3 rescued the multinucleation defect observed in MDA-MB-231 breast cancer cells. Taken together, our data reveal that non-visual arrestins are novel centrosomal components and regulate normal centrosome function.

Structure of an arrestin2-clathrin complex reveals a novel clathrin binding domain that modulates receptor trafficking.

Non-visual arrestins play a pivotal role as adaptor proteins in regulating the signaling and trafficking of multiple classes of receptors. Although arrestin interaction with clathrin, AP-2, and phosphoinositides contributes to receptor trafficking, little is known about the configuration and dynamics of these interactions. Here, we identify a novel interface between arrestin2 and clathrin through x-ray diffraction analysis. The intrinsically disordered clathrin binding box of arrestin2 interacts with a groove between blades 1 and 2 in the clathrin beta-propeller domain, whereas an 8-amino acid splice loop found solely in the long isoform of arrestin2 (arrestin2L) interacts with a binding pocket formed by blades 4 and 5 in clathrin. The apposition of the two binding sites in arrestin2L suggests that they are exclusive and may function in higher order macromolecular structures. Biochemical analysis demonstrates direct binding of clathrin to the splice loop in arrestin2L, whereas functional analysis reveals that both binding domains contribute to the receptor-dependent redistribution of arrestin2L to clathrin-coated pits. Mutagenesis studies reveal that the clathrin binding motif in the splice loop is (L/I)(2)GXL. Taken together, these data provide a framework for understanding the dynamic interactions between arrestin2 and clathrin and reveal an essential role for this interaction in arrestin-mediated endocytosis.

Arrestin2/clathrin interaction is regulated by key N- and C-terminal regions in arrestin2.

The interaction of nonvisual arrestins with clathrin is an important step in mediating the endocytosis of cell surface receptors. Previous studies have shown that mutation of the clathrin-binding box in arrestin leads to severe defects in arrestin-mediated trafficking. However, little is known about how arrestin/clathrin interaction is regulated. Here we show that both the N- and C-terminal regions of arrestin2 function to inhibit basal interaction with clathrin. Truncation analysis revealed that clathrin binding increases as the C-tail of arrestin2 is shortened while site-directed mutagenesis identified Glu-404, Glu-405, and Glu-406 as being primarily responsible for this inhibition. Mutagenesis also identified Lys-4, Arg-7, Lys-10, and Lys-11 within the N-terminus as playing a key role in regulating clathrin binding. Based on similarities with visual arrestin, Lys-10 and Lys-11 likely function as phospho sensors in arrestin2 to initially discriminate the phosphorylation status of target receptors. Analysis of the arrestin2 structure reveals that Arg-7, Lys-10, and Lys-11 are in close proximity to Glu-389 and Asp-390, suggesting that these residues may form intramolecular interactions. In fact, simultaneous mutation of Glu-389 and Asp-390 also leads to enhanced clathrin binding. These results reveal that multiple intramolecular interactions coordinately regulate arrestin2 interaction with clathrin, highlighting this interaction as a critical step in regulating receptor trafficking.

Development of Delayed Acute Subdural Hematoma after Mild Traumatic Brain Injury: A Case Report.

We report a case involving the development of a delayed acute subdural hematoma (ASDH) after trauma, with the absence of any abnormal radiological and clinical findings at initial examination. A 54-year-old male visited the emergency department after a minor trauma. The patient only complained of mild headache after head injury. He presented no abnormal findings on neurological examination, and brain computed tomography (CT) did not show any intracranial lesion or skull fractures. However, he developed seizure with disorientation eight hours after trauma, and ASDH with midline shift was found during a follow-up CT. He recovered without neurological deficits after immediate primary care and admission to the neurosurgery department. On serial follow-up CT images, a gradually increasing mass effect of hematoma was detected, and removed by craniotomy. The patient recovered without neurologic deficits.

Comparison of Complications Following Cranioplasty Using a Sterilized Autologous Bone Flap or Polymethyl Methacrylate.

OBJECTIVE: The aims of current study are to compare complications following cranioplasty (CP) using either sterilized autologous bone or polymethyl methacrylate (PMMA), and to identify the risk factors for two of the most common complications: bone flap resorption (BFR) and surgical site infection (SSI). METHODS: Between January 2004 and December 2013, 127 patients underwent CP and were followed at least 12 months. Variables, including sex, age, initial diagnosis, time interval between decompressive craniectomy (DC) and CP, operation time, size of bone flap, and presence of ventriculo-peritoneal shunt, were analyzed to identify the risk factors for BFR and SSI. RESULTS: A total of 97 (76.4%) patients underwent CP using PMMA (Group I) and 30 (23.6%) underwent CP using autologous bone (Group II). SSI occurred in 8 (8.2%) patients in Group I, and in 2 (6.7%) in Group II; there was no statistically significant difference between the groups (p=1.00). No statistically significant risk factors for SSI were found in either group. In Group I, there was no reported case of BFR. In Group II patients, BFR developed in 18 (60.0%) patients at the time of CP (Type 1 BFR), and at 12-month follow up (Type 2 BFR) in 4 (13.3%) patients. No statistically significant risk factors for BFR were found in Group II. CONCLUSION: CP using sterilized autologous bone result in a significant rate of BFR. PMMA, however, is a safe alloplastic material for CP, as it has low complication rate.

1p36 deletion syndrome confirmed by fluorescence in situ hybridization and array-comparative genomic hybridization analysis.

Pediatric epilepsy can be caused by various conditions, including specific syndromes. 1p36 deletion syndrome is reported in 1 in 5,000-10,000 newborns, and its characteristic clinical features include developmental delay, mental retardation, hypotonia, congenital heart defects, seizure, and facial dysmorphism. However, detection of the terminal deletion in chromosome 1p by conventional G-banded karyotyping is difficult. Here we present a case of epilepsy with profound developmental delay and characteristic phenotypes. A 7-year- and 6-month-old boy experienced afebrile generalized seizure at the age of 5 years and 3 months. He had recurrent febrile seizures since 12 months of age and showed severe global developmental delay, remarkable hypotonia, short stature, and dysmorphic features such as microcephaly; small, low-set ears; dark, straight eyebrows; deep-set eyes; flat nasal bridge; midface hypoplasia; and a small, pointed chin. Previous diagnostic work-up, including conventional chromosomal analysis, revealed no definite causes. However, array-comparative genomic hybridization analysis revealed 1p36 deletion syndrome with a 9.15-Mb copy loss of the 1p36.33-1p36.22 region, and fluorescence in situ hybridization analysis (FISH) confirmed this diagnosis. This case highlights the need to consider detailed chromosomal study for patients with delayed development and epilepsy. Furthermore, 1p36 deletion syndrome should be considered for patients presenting seizure and moderate-to-severe developmental delay, particularly if the patient exhibits dysmorphic features, short stature, and hypotonia.

Clinical usefulness of the measurement of serum fructosamine in childhood diabetes mellitus.

PURPOSE: Glycosylated hemoglobin (HbA1c) is often used as an indicator of glucose control. It usually reflects the average glucose levels over two to three months, and is correlated with the development of long-term diabetic complications. However, it can vary in cases of hemoglobinopathy or an altered red blood cell lifespan. The serum fructosamine levels reflect the mean glucose levels over two to three weeks. This study was designed to determine the clinical usefulness of the combined measurement of serum fructosamine and HbA1c in the management of childhood diabetes mellitus and the correlation between them. METHODS: Clinical data on 74 Korean children and adolescents with diabetes mellitus who were under management at the Department of Pediatrics of Dankook University Hospital were evaluated. Their fructosamine and HbA1c levels were reviewed based on clinical information, and analyzed using IBM SPSS Statistics ver. 21. RESULTS: Their HbA1c levels showed a strong correlation with their fructosamine levels (r=0.868, P<0.001). The fructosamine level was useful for the prompt evaluation of the recent therapeutic efficacy after the change in therapeutic modality. It was also profitable in determining the initial therapeutics and for the estimation of the onset of the disease, such as fulminant diabetes. CONCLUSION: The measurement of both fructosamine and HbA1c was useful in managing childhood diabetes mellitus, especially when there was discrepancy between the clinical information and the HbA1c level.

The status of dietary supplements intake in korean preschool children: data from the Korea national health and nutrition examination survey 2010-2012.

PURPOSE: The use of dietary supplements (DS) has increased in most nations. We investigated the amount of DS intake in the Korean population by analyzing a national survey, to support the preparation of a national institutional strategy regarding DS intake and marketing. METHODS: The data of the fifth Korea National Health and Nutrition Examination Survey (a year between 2010 and 2012) were investigated, analyzing the rate of DS intake, and the characteristics of the intake group and non-intake group in Korean preschool children. RESULTS: The intake rate of DS was 49.0-54.2% (1,313,874-1,491,240) and 19.6-30.3% (250,603-421,922) in children from 1 to 6 years old and in those less than 1 year, respectively, from 2010 to 2012. The highest intake rate was observed in the age group of five. The mean age was significantly higher in the DS intake group than in the non-intake group. Intake of essential nutrients, minerals, and vitamins were also higher in the DS intake group. The level of family income was significantly associated with the intake rate (p<0.001). In children less than 1 year, probiotics accounted for the highest intake of DS. CONCLUSION: Korean preschool children have high consumption of DS. Therefore, problems may arise from the waste of money purchasing unnecessary DS, and from the overuse of DS in preschoolers who do not require DS intake. We hope these results can be used to produce an appropriate national institutional strategy regarding DS intake and marketing.

Role of ß-arrestins and arrestin domain-containing proteins in G protein-coupled receptor trafficking.

The arrestin clan can now be broadly divided into three structurally similar subgroups: the originally identified arrestins (visual and ß-arrestins), the α-arrestins and a group of Vps26-related proteins. The visual and ß-arrestins selectively bind to agonist-occupied phosphorylated G protein-coupled receptors (GPCRs) and inhibit GPCR coupling to heterotrimeric G proteins while the ß-arrestins also function as adaptor proteins to regulate GPCR trafficking and G protein-independent signaling. The α-arrestins have also recently been implicated in regulating GPCR trafficking while Vps26 regulates retrograde trafficking. In this review, we provide an overview of the α-arrestins and ß-arrestins with a focus on our current understanding of how these adaptor proteins regulate GPCR trafficking.

Lumbar Nerve Root Compression due to Leakage of Bone Cement after Vertebroplasty.

We experienced a 73-year-old male with lumbar nerve root compression due to leakage of bone cement after vertebroplasty. He was underwent vertebroplasty for acute osteoporotic L4 compression fracture at our hospital. After vertebroplasty, his back pain was improved but right leg pain was newly developed. Lumbar computed tomography scanning showed that bone cements were leaked along the L4 nerve root. The leaked cements around L4 nerve root were removed carefully via paraspinal muscle-splitting approach. After operation, severe right leg radiating pain was improved. We recommend proper entry point, high viscosity of polymethylmethacrylate and constant monitoring can reduce complication.

Clinical analysis of epidural fluid collection as a complication after cranioplasty.

OBJECTIVE: The epidural fluid collection (EFC) as a complication of cranioplasty is not well-described in the literature. This study aimed to identify the predictive factors for the development of EFC as a complication of cranioplasty, and its outcomes. METHODS: From January 2004 to December 2012, 117 cranioplasty were performed in our institution. One-hundred-and-six of these patients were classified as either having EFC, or not having EFC. The two groups were compared to identify risk factors for EFC. Statistical significance was tested using the t-test and chi-square test, and a logistic regression analysis. RESULTS: Of the 117 patients undergoing cranioplasty, 59 (50.4%) suffered complications, and EFC occurred in 48 of the patients (41.0%). In the t-test and chi-test, risk factors for EFC were size of the skull defect (p=0.003) and postoperative air bubbles in the epidural space (p<0.001). In a logistic regression, the only statistically significant factor associated with development of EFC was the presence of postoperative air bubbles. The EFC disappeared or regressed over time in 30 of the 48 patients (62.5%), as shown by follow-up brain computed tomographic scan, but 17 patients (35.4%) required reoperation. CONCLUSION: EFC after cranioplasty is predicted by postoperative air bubbles in the epidural space. Most EFC can be treated conservatively. However, reoperation is necessary to resolve about a third of the cases. During cranioplasty, special attention is required when the skull defect is large, since EFC is then more likely.

ß-Arrestins and G protein-coupled receptor trafficking.

Arrestins are adaptor proteins that function to regulate G protein-coupled receptor (GPCR) signaling and trafficking. There are four mammalian members of the arrestin family, two visual and two nonvisual. The visual arrestins (arrestin-1 and arrestin-4) are localized in rod and cone cells, respectively, and function to quench phototransduction by inhibiting receptor/G protein coupling. The nonvisual arrestins (ß-arrestin1 and ß-arrestin2, a.k.a. arrestin-2 and arrestin-3) are ubiquitously expressed and function to inhibit GPCR/G protein coupling and promote GPCR trafficking and arrestin-mediated signaling. Arrestin-mediated endocytosis of GPCRs requires the coordinated interaction of ß-arrestins with clathrin, adaptor protein 2, and phosphoinositides such as PIP(2)/PIP(3). These interactions are facilitated by a conformational change in ß-arrestin that is thought to occur upon binding to a phosphorylated activated GPCR. In this chapter, we provide an overview of the reagents and techniques used to study ß-arrestin-mediated receptor trafficking.

The usefulness of brain magnetic resonance imaging with mild head injury and the negative findings of brain computed tomography.

OBJECTIVE: To investigate the cases of intracranial abnormal brain MRI findings even in the negative brain CT scan after mild head injury. METHODS: During a 2-year period (January 2009-December 2010), we prospectively evaluated both brain CT and brain MRI of 180 patients with mild head injury. Patients were classified into two groups according to presence or absence of abnormal brain MRI finding even in the negative brain CT scan after mild head injury. Two neurosurgeons and one neuroradiologist validated the images from both brain CT scan and brain MRI double blindly. RESULTS: Intracranial injury with negative brain CT scan after mild head injury occurred in 18 patients (10.0%). Headache (51.7%) without neurologic signs was the most common symptom. Locations of intracranial lesions showing abnormal brain MRI were as follows; temporal base (n=8), frontal pole (n=5), falx cerebri (n=2), basal ganglia (n=1), tentorium (n=1), and sylvian fissure (n=1). Intracranial injury was common in patients with a loss of consciousness, symptom duration >2 weeks, or in cases of patients with linear skull fracture (p=0.00013), and also more frequent in multiple associated injury than simple one (35.7%>8.6%) (p=0.105). CONCLUSION: Our investigation showed that patients with mild head injury even in the negative brain CT scan had a few cases of intracranial injury. These findings indicate that even though the brain CT does not show abnormal findings, they should be thoroughly watched in further study including brain MRI in cases of multiple injuries and when their complaints are sustained.