A preliminary study about the potential risks of the UV-weathered microplastic: The proteome-level changes in the brain in response to polystyrene derived weathered microplastics.

The growing use of plastic materials has resulted in a constant increase in the risk associated with microplastics (MPs). Ultra-violet (UV) light and wind break down modify MPs in the environment into smaller particles known as weathered MPs (WMPs) and these processes increase the risk of MP toxicity. The neurotoxicity of weathered polystyrene-MPs remains unclear. Therefore, it is important to understand the risks posed by WMPs. We evaluated the chemical changes of WMPs generated under laboratory-synchronized environmentally mimetic conditions and compared them with virgin MPs (VMPs). We found that WMP had a rough surface, slight yellow color, reduced molecular weight, and structural alteration compared with those of VMP. Next, 2 µg of ∼100 µm in size of WMP and VMP were orally administered once a day for one week to C57BL/6 male mice. Proteomic analysis revealed that the WMP group had significantly increased activation of immune and neurodegeneration-related pathways compared with that of the VMP group. Consistently, in in vitro experiments, the human brain-derived microglial cell line (HMC-3) also exhibited a more severe inflammatory response to WMP than to VMP. These results show that WMP is a more profound inflammatory factor than VMP. In summary, our findings demonstrate the toxicity of WMPs and provide theoretical insights into their potential risks to biological systems and even humans in the ecosystem.

Self-Similarity and Power-Law Spectra of Polymer Melts and Solutions.

Both the Rouse and Doi-Edwards models can be expressed by the relaxation spectra, in the form of power-law functions. The concept of self-similarity has offered a simple solution to many problems in polymer physics. Since the solutions derived from self-similarity are power-law functions, it is essential to check whether the relaxation spectrum of polymeric fluids can be derived by self-similarity. In this study, the power-law spectrum of an unentangled polymer solution is derived by using the self-similarity approach, which does not work for entangled polymeric fluids. Although Baumgaertel et al. (Rheol. Acta 29, 400-408 (1990)) showed that the power-law spectrum can quantitatively describe the linear viscoelasticity of monodisperse polymer melts, regardless of molecular weight, they did not find the universality of the exponent of the spectrum because they found different exponents for different polymers. Under the consideration existing the universality of linear viscoelasticity of polymer melts, this paper deals with the universality of the exponent by employing a new regression algorithm and confirms that the exponent is independent of the type of polymer.

Microglial phagocytosis of polystyrene microplastics results in immune alteration and apoptosis in vitro and in vivo.

The remarkable increase in plastic usage and widespread microplastic (MP) pollution has emerged as a substantial concern today. Many recent studies have revealed MPs as potentially hazardous substances in mammals. Despite several reports on the impact of small MPs in the brain and behaviors in aquatic animals, it is still unclear how small MPs affect the brain and its underlying cellular physiology in terrestrial animals. In this study, we investigated the accumulation of polystyrene MPs (PS-MPs) in mouse brain after oral treatment using three types of fluorescent PS-MPs of different sizes (0.2,2 and 10 µm). We found that PS-MPs were deposited in microglial cells of the brain. Following differential treatment of PS-MPs in human microglial HMC-3 cells, we identified changes in cellular morphology, immune responses, and microglial apoptosis induced by phagocytosis of 0.2 and 2 µm PS-MPs. By analyzing the PS-MP-treated HMC-3 cell transcriptome, we showed that PS-MPs treatment altered the expression of clusters of immune response genes, immunoglobulins, and several related microRNAs. In addition, we confirmed alterations in microglial differentiation marker expression with the activation of NF-κB, pro-inflammatory cytokines and apoptotic markers in PS-MP-treated human microglial cells and in mouse brain. Our findings suggest a potential risk of small PS-MPs in microglial immune activation, which leads to microglial apoptosis in murine and human brains.

Reactive Oxygen Species-Responsive Miktoarm Amphiphile for Triggered Intracellular Release of Anti-Cancer Therapeutics.

Reactive oxygen species (ROS)-responsive nanocarriers have received considerable research attention as putative cancer treatments because their tumor cell targets have high ROS levels. Here, we synthesized a miktoarm amphiphile of dithioketal-linked ditocopheryl polyethylene glycol (DTTP) by introducing ROS-cleavable thioketal groups as linkers between the hydrophilic and hydrophobic moieties. We used the product as a carrier for the controlled release of doxorubicin (DOX). DTTP has a critical micelle concentration (CMC) as low as 1.55 µg/mL (4.18 × 10-4 mM), encapsulation efficiency as high as 43.6 ± 0.23% and 14.6 nm particle size. The DTTP micelles were very responsive to ROS and released their DOX loads in a controlled manner. The tocopheryl derivates linked to DTTP generated ROS and added to the intracellular ROS in MCF-7 cancer cells but not in HEK-293 normal cells. In vitro cytotoxicity assays demonstrated that DOX-encapsulated DTTP micelles displayed strong antitumor activity but only slightly increased apoptosis in normal cells. This ROS-triggered, self-accelerating drug release device has high therapeutic efficacy and could be a practical new strategy for the clinical application of ROS-responsive drug delivery systems.

Physiochemical properties and resorption progress of porcine skin-derived collagen membranes: In vitro and in vivo analysis.

The aim of the present study was to evaluate the physiochemical properties and resorption progress of two cross-linked, porcine skin-derived collagen membranes and compare their features with those of a membrane without cross-linking (Bio-Gide® [BG], Geistlich Biomaterials, Wolhusen, Switzerland). Three porcine skin-derived collagen membranes, dehydrothermally (DHT) cross-linked (experimental), DHT and 1-ethyl-3(3-dimethylaminopropyl)-carbodiimide (DHT/EDC) cross-linked (experimental) and BG were investigated for their morphology, enzyme resistance, and tensile strength in vitro and biodegradation in vivo. DHT and DHT/EDC membranes exhibited irregular, interconnected macro- and micropores that formed a 3D mesh, whereas BG exhibited individual collagen fibrils interlaced to form coarse collagen strands. In enzyme resistance and tensile strength tests, DHT and DHT/EDC membranes demonstrated good resistance and mechanical properties compared with BG. In vivo, all three membranes were well integrated into the surrounding connective tissue. Thus, the DHT membrane exhibited its potential as a barrier membrane for guided bone and tissue regeneration.

Effect of molecular weight of hyaluronic acid (HA) on viscoelasticity and particle texturing feel of HA dermal biphasic fillers.

BACKGROUND: Hyaluronic acid (HA) dermal biphasic fillers are synthesized for their efficacy in correcting aesthetic defects such as wrinkles, scars and facial contouring defects. The fillers consist of crosslinked HA microspheres suspended in a noncrosslinked HA. To extend the duration of HAs within the dermis and obtain the particle texturing feel, HAs are crosslinked to obtain the suitable mechanical properties. RESULTS: Hyaluronic acid (HA) dermal biphasic fillers are prepared by mixing the crosslinked HA microspheres and the noncrosslinked HAs. The elastic modulus of the fillers increased with raising the volume fraction of the microspheres. The mechanical properties and the particle texturing feel of the fillers made from crosslinked HA (1058 kDa) microspheres suspended in noncrosslinked HA (1368 kDa) are successfully achieved, which are adequate for the fillers. CONCLUSIONS: Dermal biphasic HA fillers made from 1058 kDa exhibit suitable elastic moduli (211 to 420 Pa) and particle texturing feel (scale 7 ~ 9).

Surface characteristics of a novel hydroxyapatite-coated dental implant.

PURPOSE: This study evaluated the surface characteristics and bond strength produced using a novel technique for coating hydroxyapatite (HA) onto titanium implants. METHODS: HA was coated on the titanium implant surface using a super-high-speed (SHS) blasting method with highly purified HA. The coating was performed at a low temperature, unlike conventional HA coating methods. Coating thickness was measured. The novel HA-coated disc was fabricated. X-ray diffraction analysis was performed directly on the disc to evaluate crystallinity. Four novel HA-coated discs and four resorbable blast medium (RBM) discs were prepared. Their surface roughnesses and areas were measured. Five puretitanium, RBM-treated, and novel HA-coated discs were prepared. Contact angle was measured. Two-way analysis of variance and the post-hoc Scheffe's test were used to analyze differences between the groups, with those with a probability of P<0.05 considered to be statistically significant. To evaluate exfoliation of the coating layer, 7 sites on the mandibles from 7 mongrel dogs were used. Other sites were used for another research project. In total, seven novel HA-coated implants were placed 2 months after extraction of premolars according to the manufacturer's instructions. The dogs were sacrificed 8 weeks after implant surgery. Implants were removed using a ratchet driver. The surface of the retrieved implants was evaluated microscopically. RESULTS: A uniform HA coating layer was formed on the titanium implants with no deformation of the RBM titanium surface microtexture when an SHS blasting method was used. CONCLUSIONS: These HA-coated implants exhibited increased roughness, crystallinity, and wettability when compared with RBM implants.

[Relationship of prenatal stress and depression to maternal-fetal attachment and fetal growth].

PURPOSE: Prenatal depression is associated with potential negative consequences for the mother and infant. The purpose of this study was to examine pregnant women's stress, and depression and their impact on maternal-fetal attachment and fetal growth. METHODS: Data were collected by means of a questionnaire and fetal sonogram from a convenience sample of 166 pregnant women. RESULTS: Women who have a low educational level, poor health and are dissatisfied with their marriage showed low maternal-fetal attachment. Prenatal depression had significant correlations with length of pregnancy and level of stress. Even though correlation between maternal stress and fetal weight (r=-.15, p=.099) and correlation between maternal depression and maternal-fetal attachment (r=-.13, p=.095) were not statistically significant, the impact of the prenatal psychological state of mothers can not be ignored as it relates to fetal health. CONCLUSION: Maternal-fetal attachment and fetal growth can be affected by maternal emotional state, including stress or depression. These findings suggest that primary care nurses in hospitals and public health centers should provide prenatal depression screening and nursing intervention programs for management and prevention of prenatal stress and depression.

Professional values in Korean undergraduate nursing students.

Developing professional values among undergraduate nursing students is important since such values are a significant predictor of quality care, clients' recognition, and therefore nurses' job satisfaction. This study explored South Korean nursing students' perception of nursing professional values (NPV) and compared the NPV scores between groups according to participants' demographic characteristics. The study participants comprised of 529 students, mostly female (96.4%), with a mean age of 22.29years, sampled from six universities throughout the country. The NPV scores, measured with the 29-item Likert scale developed by Yeun et al. (2005), were significantly higher in students who entered nursing schools following their aptitude or desire for professional job than in those who entered the schools just because their entrance exam scores were sufficient. The NPV scores were also higher in students who were planning to pursue graduate study than in those who had not yet decided. The NPV scores were significantly different between the six regions, suggesting needs of in-depth studies to understand the underlying reasons. The NPV scores were not correlated, at the .05 level of significance, with academic year, gender, or academic performance.

Antitumor effect of a transducible fusogenic peptide releasing multiple proapoptotic peptides by caspase-3.

We have designed a novel peptide, TK3, composed of three functional domains, a protein transduction domain, a TAT followed by three tandem repeats of a proapoptotic peptide, and a caspase-3 cleavage site, (KLAKLAK)(2)-DEVD. TK3 was able to transduce into cells and then activate caspase-3, which in turn cleaved TK3 to release additional (KLAKLAK)(2) peptides. (KLAKLAK)(2) was well transduced by TAT into tumor cells and was able to induce apoptosis in vitro and in vivo. TK3 also induced apoptosis and inhibited angiogenesis in endothelial cells. Further, direct injection of TK3 into established B16F10 melanoma tumors in C57BL/6 mice resulted in almost complete inhibition of the tumor growth. These results suggest that TK3 could be beneficial for the treatment of accessible tumors and used as an adjuvant for cancer therapy.

Targeting bladder tumor cells in vivo and in the urine with a peptide identified by phage display.

Bladder cancer is one of the most common tumors of the genitourinary tract. Here, we use phage display to identify a peptide that targets bladder tumor cells. A phage library containing random peptides was screened for binding to cells from human bladder tumor xenografts. Phage clones were further selected for binding to a bladder tumor cell line in culture. Six clones displaying the consensus sequence CXNXDXR(X)/(R)C showed selective binding to cells from primary human bladder cancer tissue. Of these, the CSNRDARRC sequence was selected for further study as a synthetic peptide. Fluorescein-conjugated CSNRDARRC peptide selectively bound to frozen sections of human bladder tumor tissue, whereas only negligible binding to normal bladder tissue was observed. When the fluorescent peptide was introduced into the bladder lumen, in a carcinogen-induced rat tumor model, it selectively bound to tumor epithelium. Moreover, when the peptide was intravenously injected into the tail vein, it homed to the bladder tumor but was not detectable in normal bladder and control organs. Next, we examined whether the peptide can detect tumor cells in urine. The fluorescent peptide bound to cultured bladder tumor cells but not to other types of tumor cell lines. Moreover, it bound to urinary cells of patients with bladder cancer, while showing little binding to urinary cells of patients with inflammation or healthy individuals. The CSNRDARRC peptide may be useful as a targeting moiety for selective delivery of therapeutics and as a diagnostic probe for the detection of bladder cancer.

Development of child and adolescent psychiatric nursing practice in Korea, 1980-2000.

PROBLEM: Although the need for mental health services for children and youth is on the rise in Korea, there are no data available regarding the current status of psychiatric nurses working with children and adolescents. METHODS: Descriptive statistics were used to analyze questionnaires from 324 respondents. FINDINGS: Only 5% of psychiatric nurses in Korea are working at child and adolescent-specific programs. The level of nurses' roles and functions vary from simple to specialized. CONCLUSIONS: More effort should be put into networking among nurses to exchange updated information and to share nursing strategies and strengthen college education for further specialization and expansion of nursing roles in the various settings.