Sleep disturbance correlated with severity of neuropathic pain in sciatic nerve crush injury model.

The association between sleep and pain has been investigated widely. However, inconsistent results from animal studies compared with human data show the need for a validated animal model in the sleep-pain association field. Our study aims to validate common neuropathic pain models as a tool for evaluating the sleep-pain association. Electrodes electroencephalogram (EEG) and electromyogram (EMG) were surgically implanted to measure sleep. The von Frey test was used to measure pain sensitivity. Following the baseline data acquisition, two pain-modelling procedures were performed: sciatic nerve crush injury (SCI) and common peroneal nerve ligation (CPL). Post-injury measurements were performed on days 1, 5, 10, and 15 post-surgery. The results presented decreased paw withdrawal thresholds and reduced NREM sleep duration in both models on the first post-surgery day. In the SCI model, NREM sleep duration was negatively correlated with paw withdrawal thresholds (p = 0.0466), but not in the CPL model. Wake alpha and theta EEG powers were also correlated with the pain threshold. The results confirm that the SCI model shows disturbed sleep patterns associated with increased pain sensitivity, suggesting it is a reliable tool for investigating sleep disturbances associated with neuropathic pain.

Effects of the etching process on the surface, friction and wear characteristics of silicone rubber coated with micro-sized ceramic particles.

This study investigates the friction and wear characteristics of silicone rubber used in hydraulic systems, focusing on surface properties achieved through coating strategies. Silicone rubber specimens with varying surface characteristics, prepared by coating with micro-sized ceramic particles and employing etching processes, were examined. Surface morphology, roughness, water droplet contact angles, and friction and wear characteristics were evaluated. The silicone rubber was coated with ceramic particles (average size: 16 µm) and subsequently etched for different durations (1, 5, 10, 30, and 60 minutes). The results revealed that longer etching times led to increased surface roughness, while shorter etching times resulted in improved wear characteristics. The friction coefficient demonstrated a discernible reduction with escalating etching durations, with Etching-60M showing approximately 50% lower friction coefficient compared to Etching-1M. Wear rates ranged from 2.47 × 10-7 to 1.43 × 10-6 mm3 N-1 mm-1, indicating an increasing trend with longer etching times. Distinct wear mechanisms were observed between non-etched and etched specimens, with the latter exhibiting more pronounced wear tracks. Finite element analysis highlighted variations in stress behavior during contact sliding, indicating that surface modifications significantly impact wear resistance. While longer etching times improved friction characteristics, shorter etching times yielded superior wear characteristics. Further research is recommended to explore optimal etching conditions considering various variables.

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.

Efficient brazzein production in yeast (Kluyveromyces lactis) using a chemically defined medium.

The sweet-tasting protein brazzein offers considerable potential as a functional sweetener with antioxidant, anti-inflammatory, and anti-allergic properties. Here, we optimized a chemically defined medium to produce secretory recombinant brazzein in Kluyveromyces lactis, with applications in mass production. Compositions of defined media were investigated for two phases of fermentation: the first phase for cell growth, and the second for maximum brazzein secretory production. Secretory brazzein expressed in the optimized defined medium exhibited higher purity than in the complex medium; purification was by ultrafiltration using a molecular weight cutoff, yielding approximately 107 mg L-1. Moreover, the total media cost in this defined medium system was approximately 11% of that in the optimized complex medium to generate equal amounts of brazzein. Therefore, the K. lactis expression system is useful for mass-producing recombinant brazzein with high purity and yield at low production cost and indicates a promising potential for applications in the food industry.

Reconstruction of the corticorubral tract in the human brain using diffusion tensor tractography.

The corticorubral tract (CRT) facilitates fine motor coordination. However, no diffusion tensor tractography (DTT) study has been conducted although a few studies have reported on the cortical connection of the red nucleus. In this study, we investigated the DTT reconstruction method and DTT characteristics of the CRT in normal subjects. Thirty-six right-handed normal subjects were recruited. Diffusion tensor images were scanned using a 1.5 T MRI scanner. For analysis of the CRT, the seed region of interest (ROI) was placed on the red nucleus of the midbrain, and the target ROI was placed on the primary sensorimotor cortex. Values of fractional anisotropy (FA), mean diffusivity (MD), and tract volume (TV) of the CRT were obtained for both hemispheres. Among the 72 cerebral hemispheres of the 36 normal subjects, the neural tract between the red nucleus and the primary sensorimotor cortex was reconstructed in 66 hemispheres (92%). The reconstructed CRT, which originated from the primary sensorimotor cortex, descended through the posterior portion of the centrum semiovale, the corona radiata and posterior limb of the internal capsule, and terminated at the red nucleus. Analysis of the FA, MD, and TV values revealed no significant differences between the right and left hemispheres (p > 0.05). We describe the method of DTT reconstruction and the imaging parameters of the CRT in the brain of normal subjects. We believe that the DTT method and associated parameter results for the CRT in normal subjects will be useful in future neuroscience studies.

White Matter Abnormalities in Spontaneous Subarachnoid Hemorrhage: A Tract-Based Spatial Statistics Study.

BACKGROUND AND PURPOSE: We investigated white matter abnormalities in patients with spontaneous subarachnoid hemorrhage following aneurysmal rupture, by using tract-based spatial statistics. METHODS: Sixteen patients with spontaneous subarachnoid hemorrhage due to aneurysmal rupture and 18 age- and sex-matched healthy control subjects were recruited. Voxel-wise statistical analysis of fractional anisotropy data was performed by using tract-based spatial statistics as implemented in the Functional Magnetic Resonance Imaging of the Brain Software Library. We calculated mean fractional anisotropy values across the tract skeleton and within 48 regions of interest based on the intersections between the fractional anisotropy skeleton and the probabilistic Johns Hopkins University white matter atlases. RESULTS: Comparing the patient and control groups, the fractional anisotropy values of 44 regions of interest among the 48 regions of interest showed significant differences (P<0.05). However, significant differences were not observed in the remaining 4 regions of interest (both retrolenticular parts of the internal capsule, the right superior longitudinal fasciculus, and the right superior corona radiata; P>0.05). CONCLUSIONS: By undertaking tract-based spatial statistics analysis, we detected wide-ranging white matter abnormalities in patients with spontaneous subarachnoid hemorrhage. Registration: URL: http://www.e-irb.com/index.jsp. Unique identifier: 2019-06-032.

Abdominal pain due to the spinothalamic tract injury in patients with mild traumatic brain injury: a case report.

BACKGROUND: We report on a patient with a mild traumatic brain injury (TBI) who developed abdominal pain due to spinothalamic tract (STT) injuries revealed by diffusion tensor tractography (DTT). CASE PRESENTATION: A 53-year-old female patient suffered head trauma resulting from a backward fall. While bathing at a public bathhouse, she fell backward and struck the occipital area of her head against the floor. After the head trauma, she experienced pain in the abdomen and in both hands and feet. She underwent evaluations including conventional brain MRI, abdominal and pelvic ultrasonography, and stomach and intestine endoscopy. No abnormality was observed in her brain or abdomen. In addition, her abdominal pain had not been relieved by medical management. When she came to our hospital 4 years after the head trauma, her pain characteristics and severity were as follows: intermittent pain without allodynia or hyperalgesia; squeezing and warm creeping-like pain in the abdomen (visual analog scale score: 7); tingling pain in both hands and feet (visual analog scale score: 7). She was prescribed pregabalin and gabapentin, and her abdominal and limb pain was well-controlled at a tolerable level. On DTT 4 years after head trauma, the upper portion of the spinothalamic tracts (STTs) in both hemispheres showed partial tearing. DISCUSSION AND CONCLUSIONS: Injury of the STT was demonstrated by using DTT in a patient who showed abdominal pain that was refractory to medical management following mild TBI. Our results suggest that central pain due to STT injury might be suspected in patients with abdominal pain that is refractory to medical management following TBI.

Histidine residues at the copper-binding site in human tyrosinase are essential for its catalytic activities.

Tyrosinase is a copper-binding enzyme involved in melanin biosynthesis. However, the detailed structure of human tyrosinase has not yet been solved, along with the identification of the key sites responsible for its catalytic activity. We used site-directed mutagenesis to identify the residues critical for the copper binding of human tyrosinase. Seven histidine mutants in the two copper-binding sites were generated, and catalytic activities were characterised. The tyrosine hydroxylase activities of the CuA site mutants were approximately 50% lower than those of the wild-type tyrosinase, while the dopa oxidation activities of the mutants were not significantly different from that of wild-type tyrosinase. By contrast, mutations at CuB significantly decreased both tyrosine hydroxylation and dopa oxidation activities, confirming that the catalytic sites for these two activities are at least partially distinct. These findings provide a useful resource for further structural determination and development of tyrosinase inhibitors in the cosmetic and pharmaceutical industries.

Optimized production and quantification of the tryptophan-deficient sweet-tasting protein brazzein in Kluyveromyces lactis.

The sweet-tasting protein brazzein is a candidate sugar substitute owing to its sweet, sugar-like taste and good stability. To commercialize brazzein as a sweetener, optimization of fermentation and purification procedure is necessary. Here, we report the expression conditions of brazzein in the yeast Kluyveromices lactis and purification method for maximum yield. Transformed K. lactis was cultured in YPGlu (pH 7.0) at 25 °C and induced by adding glucose:galactose at a weight ratio of 1:2 (%/%) during the stationary phase, which increased brazzein expression 2.5 fold compared to the previous conditions. Cultures were subjected to heat treatment at 80 °C for 1 h, and brazzein containing supernatant was purified using carboxymethyl-sepharose cation exchange chromatography using 50 mM NaCl in 50 mM sodium acetate buffer (pH 4.0) as a wash buffer and 400 mM NaCl (pH 7.0) for elution. The yield of purified brazzein under these conditions was 2.0-fold higher than that from previous purification methods. We also determined that the NanoOrange assay was a suitable method for quantifying tryptophan-deficient brazzein. Thus, it is possible to obtain pure recombinant brazzein with high yield in K. lactis using our optimized expression, purification, and quantification protocols, which has potential applications in the food industry.

Splenic malignant fibrous histiocytoma with concurrent hypertension and epistaxis in an Alaskan malamute dog.

BACKGROUND: Malignant fibrous histiocytoma has been uncommonly described in dogs. Several extranasal neoplasias have been reported to result hypertensive epistaxis. There are, however, no published case reports of extranasal malignant fibrous histiocytoma with concurrent hypertension and epistaxis in dogs. CASE PRESENTATION: A 10-year-old dog presented with a spontaneous massive epistaxis persisting for 5 days. The dog exhibited unstable hypertension, which was considered as a cause of epistaxis. The complete blood count, prothrombin time, and activated partial thromboplastin time were within the reference limits, and other systemic examination showed no abnormalities except for a splenic mass occupying more than one third of the abdomen. Histologic examination of the resected spleen revealed the characteristic features of a malignant fibrous histiocytoma. One week after splenectomy, the hypertension and epistaxis resolved clinically and did not recur on the 5-month follow-up. CONCLUSIONS: The dog's blood pressure and epistaxis normalized after malignant fibrous histiocytoma resection suggesting that hypertensive epistaxis may be a rare manifestation of canine malignant fibrous histiocytoma.

Gas-mediated vitreomacular adhesion release with intravitral ranibizumab injections for exudative age-related macular degeneration.

PURPOSE: To evaluate the efficiency of gas-assisted vitreomacular adhesion (VMA) release combined with intravitreal ranibizumab injections for exudative age-related macular degeneration (AMD) patients. MATERIALS AND METHODS: This prospective, interventional case series included a total of 23 eyes of 22 patients. The eyes were treated with intravitreal injection of 0.3 mL of perfluoropropane (C3F8) gas and concomitant intravitreal ranibizumab injection to stimulate VMA release. After three initial loading injections, additional intravitreal ranibizumab injections were performed pro re nata. Over a 12-month period, monthly examinations were performed for best-corrected visual acuity (BCVA, logMAR; logarithm of the minimum angle resolution), optical coherence tomography, and dilated fundus examinations. RESULTS: After gas injection, 22 eyes (95.7 %) showed complete VMA release at 1 week. Complete VMA was achieved in all eyes at 2 months after VMA release, without serious ocular adverse events except one patient who developed a retinal tear. Mean BCVA was 0.61 ± 0.37 logMAR (20/81 Snellen equivalents) at baseline and 0.46 ± 0.30 logMAR (20/57 Snellen equivalents) at 12 months (P = 0.135). Mean central macular thickness was 357.9 ± 128.6 µm at baseline and 245.6 ± 60.0 µm at 12 months (P = 0.188). Mean numbers of intravitreal ranibizumab injections were 4.8 ± 2.4 times during 12 months (4 to 8 injections). CONCLUSION: Gas-assisted VMA release can be used as an efficient alternative for exudative AMD patients with obvious VMA.

Folic Acid-Functionalized Polythiophene for Targeted Cellular Imaging.

Polythiophene containing pendant N-hydroxysuccinimide (NHS) ester groups was reacted with poly(ethylene glycol) (PEG) and oleylamine, which was subsequently modified with folic acid to prepare a targeting fluorescent cellular imaging probe. The amphiphilic character of the folic acid-functionalized polythiophene induced the formation of nanoparticles with an average diameter of 95.3 nm in water. This polymer shows good photostability and low toxicity toward KB cells at a high concentration (100 µg/mL), which meets the crucial requirement for cellular imaging and other biological applications. The folic acid-functionalized polythiophene could be internalized efficiently into KB cells and accumulated in the cytoplasm to yield bright fluorescence, indicating that it is a good candidate material for the fluorescence imaging of living cells.

Intraoperative echocardiographic delineation of the high take-off coronary ostia during an extensive surgical repair of the bicuspid aortic valve and dilated sinotubular junction: a case report.

BACKGROUND: This study reports the efficacy of intraoperative transesophageal echocardiography (TEE) for evaluation of high take-off coronary ostia and proximal coronary arterial flows as an alternative to preoperative coronary angiography. CASE PRESENTATION: In a 65-year old male undergoing the bicuspid aortic valve (BAV) repair and the extensive remodeling of dilated sinus and tubular junction, and preoperative coronary angiography were unsuccessfully completed due to an allergic reaction to the contrast medium. Intraoperative TEE by employing various 3-dimensional volume images of coronary ostia and Doppler tracings of the coronary arterial flows enabled a thorough pre-procedural evaluation of the high take-off coronary arteries and post-procedural evaluation by confirming the absence of any compromise in coronary arterial flow. CONCLUSION: In the present case, intraoperative application of various TEE imaging modalities enabled comprehensive evaluation of high-taking off coronary artery, as an alternative to preoperative coronary angiography, in a patient undergoing an extensive aortic valve and aortic root repair procedure.

Rapid detection of 6×-histidine-labeled recombinant proteins by immunochromatography using dye-labeled cellulose nanobeads.

A rapid and easy immunochromatography assay using dye-labeled cellulose nanobeads (CNBs) was developed to detect proteins with hexa-histidine tag (His-tag) to characterize recombinant proteins during purification. Recombinant ATG8 protein was used as a His-tagged protein, and ATG8-conjugated CNBs (A-CNBs) were prepared. The original ATG8 in the sample solution competed with A-CNBs for anti-His-tag antibodies spotted on to the strip resulting in an inverse relationship between ATG8 concentration and the colorimetric signal. The usefulness of this method was shown by adding ATG8 to a 1% Escherichia coli extract. In addition, this assay can be used to detect other His-tagged proteins without protein-specific antibodies. Because the identification of fractions containing His-tagged proteins by western blotting or ELISA is labor-intensive and expensive, our method provides an efficient and cheaper alternative.

Impact of Tribological Conditions on Collagen Coating Self-Healing.

The study examined the correlation between collagen coating damage and self-healing under various tribological conditions. It confirmed that the friction coefficient and degree of damage on the collagen coating varied based on contact and sliding conditions. The friction coefficient, measured at 0.56 for a single sliding cycle under a 350 mN normal load, demonstrated a notable decrease to 0.46 for 2295 cycles under 30 mN, further reducing to 0.15 for 90 cycles under a 20 mN normal load. As the normal load increased, the friction coefficient decreased, and with repeated sliding cycles under the same load, the coefficient also decreased. Water droplets induced a self-healing effect on collagen coating, causing wear tracks to vanish as fibers absorbed water. Severe wear tracks, with broken fibers and peeled coating, showed limited self-healing. In contrast, mild wear tracks, with compressed yet connected fibers, exhibited the self-healing phenomenon, making the wear tracks disappear. Real-time observations during 90 cycles under a 20 mN normal load highlighted the formation of mild wear tracks with intact collagen fibers, providing quantitative insights into self-healing characteristics. To preserve the self-healing effect of the collagen coating, it is essential to ensure tribological conditions during contact and sliding that prevent the disconnection of collagen fibers.

Enhancement of tribological performance of lubricants using polydimethylsiloxane powder additives.

This study explored the potential enhancement of lubrication performance by incorporating polydimethylsiloxane (PDMS) powder as a lubricant additive. The PDMS powder was successfully synthesized via mechanical and thermal processes, exhibiting a particle size distribution with an average diameter of 39 µm. XRD and FTIR analyses confirmed the amorphous structure and chemical composition of the PDMS-based silicone rubber powder. XPS analysis provided evidence of increased crosslinking in the crosslinked PDMS powders, with shifts in binding energies and changes in elemental ratios, supporting enhanced Si-O-Si network formation. The addition of the powder to the Poly alpha Olefin (PAO)-based lubricating oil induced notable changes in the physicochemical properties, including viscosity and contact angle. Friction tests revealed that the introduction of silicone rubber powder did not compromise the friction behavior of the lubricating oil owing to the soft and deformable nature of the powder particles, which minimized direct metal-to-metal contact. A significant observation was the decreasing trend in the wear rate with increasing powder concentration, which reached a minimum at 2 wt%. This phenomenon is attributed to a synergistic combination of particle deformation, stress absorption/dispersion effects, and lubricating film formation. Optical microscopy analysis provided visual evidence supporting the low wear rate, with specimens containing 1 wt% and 2 wt% concentrations exhibiting narrow wear widths and reduced wear particle adhesion. Further augmentation of the wear resistance and durability is anticipated through the addition of silicone rubber curing agents, which are expected to bolster the mechanical strength and load-bearing capacity of PDMS powder particles while enhancing the stability of the lubricating film.

Solar-Powered AEM Electrolyzer via PGM-Free (Oxy)hydroxide Anode with Solar to Hydrogen Conversion Efficiency of 12.44.

Water electrolyzers powered by renewable energy are emerging as clean and sustainable technology for producing hydrogen without carbon emissions. Specifically, anion exchange membrane (AEM) electrolyzers utilizing non-platinum group metal (non-PGM) catalysts have garnered attention as a cost-effective method for hydrogen production, especially when integrated with solar cells. Nonetheless, the progress of such integrated systems is hindered by inadequate water electrolysis efficiency, primarily caused by poor oxygen evolution reaction (OER) electrodes. To address this issue, a NiFeCo─OOH has developed as an OER electrocatalyst and successfully demonstrated its efficacy in an AEM electrolyzer, which is powered by renewable electricity and integrated with a silicon solar cell.