Effects of Continuous Positive Airway Pressure on White Matter Microstructure in Patients With Obstructive Sleep Apnea

Background and Objective Obstructive sleep apnea (OSA) has significant effects on quality of life and may lead to cognitive impairments. Continuous positive airway pressure (CPAP) is the standard treatment for OSA and has been shown to improve sleep disturbances and daytime dysfunction. In this study, we aimed to assess the effects of CPAP on white matter (WM) integrity using longitudinal diffusion tensor imaging (DTI) tests. Methods Twenty-two male patients with moderate to severe OSA were recruited, and thepatients underwent DTI scanning before and 6–44 months after CPAP treatment. Sixteen male patients with untreated OSA who were not compliant with CPAP were included as a reference group. We compared the functional anisotropy (FA) values between baseline and follow-up magnetic resonance imaging in both the CPAP and untreated groups using tract-specific statistical analysis (TSSA) method. Results The TSSA analysis showed that FA values in the middle part of the right corticospinal tract were increased after treatment in the CPAP group. In the untreated group, no significant change in FA value was observed between baseline and follow-up. In the CPAP group, the post-treatment FA value in the anterior part of the right anterior thalamic radiation was significantly correlated with the duration of CPAP therapy, after controlling for age, body mass index, and baseline FA value. Conclusions Our study suggests that long-term CPAP treatment could gradually reverse OSA-induced injury to the WM microstructure, particularly WM associated with the motor and limbic systems. The study findings provide new insights into the mechanisms of cognitive improvement after CPAP treatment in patients with OSA

Nanoarrays of tethered lipid bilayer rafts on poly(vinyl alcohol) hydrogels

Lipid rafts are cholesterol-and sphingolipid-rich domains that function as platforms for signal transduction and other cellular processes. Tethered lipid bilayers have been proposed as a promising model to describe the structure and function of cell membranes. We report a nano(submicro) array of tethered lipid bilayer raft membranes (tLBRMs) comprising a biosensing platform. Poly(vinyl alcohol) (PVA) hydrogel was directly patterned onto a solid substrate, using ultraviolet-nanoimprint lithography (UV-NIL), as an inert barrier to prevent biofouling. The robust structures of the nanopatterned PVA hydrogel were stable for up to three weeks in phosphate-buffered saline solution despite significant swelling (100% in height) by hydration. The PVA hydrogel strongly restricted the adhesion of vesicles, resulting in an array of highly selective hydrogel nanowells. tLBRMs were not formed by direct vesicle fusion, although raft vesicles containing poly(ethylene glycol) lipopolymer were selectively immobilized on gold substrates patterned with PVA hydrogel. The deposition of tLBRM nano(submicro) arrays was accomplished by a mixed, self-assembled monolayer-assisted vesicle fusion method. The monolayer was composed of a mixture of 2-mercaptoethanol and poly(ethylene glycol) lipopolymer, which promoted vesicle rupture. These results suggest that the fabrication of inert nanostructures and the site-selective modification of solid surfaces to induce vesicle rupture may be essential in the construction of tLBRM nano(submicro) arrays using stepwise self-assembly.This work was supported by Core Research for Evolutional Science and Technology (CREST) of Japan Science and Technology Agency (JST), and New Energy and Indstrial Technology Development Organization (NEDO)

A new knotless parametrial tissue ligation technique for safe total laparoscopic hysterectomy

Objective Parametrial tissue ligation during total laparoscopic hysterectomy (TLH) is important in large uteri with large vessels. Methods A retrospective study was performed at Asan Medical Center for comparing TLH performed with a new knotless parametrial tissue ligation method and conventional laparoscopic-assisted vaginal hysterectomy (LAVH) from March 2019 to August 2021. For TLH, after anterior colpotomy, the parametrial tissue was ligated by anchoring the suture and making a loop in one direction three times using 1-0 V-LocTM 180 (Covidien, Mansfield, MA, USA) suture. Subsequently, the cranial part of the loop was cut using an endoscopic device. Results A total of 119 and 178 patients were included in the TLH and LAVH groups, respectively. The maximal diameter of the uterus was larger in the TLH group (106.29±27.16 cm) than in the LAVH group (99.00±18.92 cm, P=0.01). The change in hemoglobin (Hb) level was greater in the LAVH group than in the TLH group (P1,000 g, the operative times and change in Hb levels were similar between the two groups. In both groups, no ureteral complications occurred during or after surgery. Conclusion Knotless parametrial tissue ligation using 1-0 V-LocTM 180 suture in TLH can be safely applied, even in cases with large uteri, without increased risks of ureteral injury or uterine bleeding

Soft lithographic patterning of supported lipid bilayers onto a surface and inside microfluidic channels

We present simple soft lithographic methods for patterning supported lipid bilayer (SLB) membranes onto a surface and inside microfluidic channels. Micropatterns of polyethylene glycol (PEG)-based polymers were fabricated on glass substrates by microcontact printing or capillary moulding. The patterned PEG surfaces have shown 97 +/- 0.5% reduction in lipid adsorption onto two dimensional surfaces and 95 +/- 1.2% reduction inside microfluidic channels in comparison to glass control. Atomic force microscopy measurements indicated that the deposition of lipid vesicles led to the formation of SLB membranes by vesicle fusion due to hydrophilic interactions with the exposed substrate. Furthermore, the functionality of the patterned SLBs was tested by measuring the binding interactions between biotin (ligand)-labeled lipid bilayer and streptavidin (receptor). SLB arrays were fabricated with spatial resolution down to similar to 500 nm on flat substrate and similar to 1 mu m inside microfluidic channels, respectively.This work was supported by the Micro Thermal System Research Center of Seoul National University and Core Research for Evolutional Science and Technology (CREST) of Japan Science and Technology Corporation

Isolation and Characterization of a Defensin-Like Peptide (Coprisin) from the Dung Beetle, Copris tripartitus

The antibacterial activity of immune-related peptides, identified by a differential gene expression analysis, was investigated to suggest novel antibacterial peptides. A cDNA encoding a defensin-like peptide, Coprisin, was isolated from bacteria-immunized dung beetle, Copris tripartitus, by using differential dot blot hybridization. Northern blot analysis showed that Coprisin mRNA was up-regulated from 4 hours after bacteria injection and its expression level was reached a peak at 16 hours. The deduced amino acid sequence of Coprisin was composed of 80 amino acids with a predicted molecular weight of 8.6 kDa and a pI of 8.7. The amino acid sequence of mature Coprisin was found to be 79.1% and 67.4% identical to those of defensin-like peptides of Anomala cuprea and Allomyrina dichotoma, respectively. We also investigated active sequences of Coprisin by using amino acid modification. The result showed that the 9-mer peptide, LLCIALRKK-NH2, exhibited potent antibacterial activities against Escherichia coli and Staphylococcus aureus

Molded nanowell electrodes for site-selective single liposome arrays

We present a nanowell (NW)-based biosensing platform for electrochemically detecting biological reactions on the level of single lipid vesicle. The NW geometry of a gently-sloped vertical wall is found to be optimal for selective deposition of single liposomes without capillary resistances. Also, the use of a hydrophilic, non-biofouling PEG copolymer is essential to provide distinctively separated FLV arrays without nonspecific adsorption.This work was supported by the Korea Research Foundation Grant funded by the Korean Government (MOEHRD, Basic Research Promotion Fund) (KRF-2006-003-D00040) and the Micro Thermal System Research Center of Seoul National University. This work was also supported by Core Research for Evolutional Science and Technology (CREST) of Japan Science and Technology Corporation

Novel neuroelectrophysiological age index associated with imaging features of brain aging and sleep disorders

•We proposed a sleep EEG-based brain age prediction model using convolutional neural networks.•A higher BAI is associated with cortical thinning in various functional areas.•A higher BAI for sleep disorder groups compared to healthy sleepers, as well as significant differences in the spectral pattern of EEG among different sleep disorders (lower power in slow and θ waves for sleep apnea vs. higher power in β and σ for insomnia).•This result suggested that sleep EEG-BAI may reflect not only neural electroactivity responding to the same night sleep quality/depth but also neuroelectrophysiological changes in relation to chronic neural loss and altered brain connectivity.•Suggested EEG-based BAI can be used to phenotype sleep disorders as well as screen for sleep abnormalities that potentially harm brain health. Sleep architecture and microstructures alter with aging and sleep disorder-led accelerated aging. We proposed a sleep EEG based brain age prediction model using convolutional neural networks. We then associated the estimated brain age index with brain structural aging features, sleep disorders and various sleep parameters. Our model also showed a higher BAI (predicted brain age minus chronological age) is associated with cortical thinning in various functional areas. We found a higher BAI for sleep disorder groups compared to healthy sleepers, as well as significant differences in the spectral pattern of EEG among different sleep disorders (lower power in slow and ϑ waves for sleep apnea vs. higher power in β and σ for insomnia), suggesting sleep disorder-dependent pathomechanisms of aging. Our results demonstrate that the new EEG-BAI can be a biomarker reflecting brain health in normal and various sleep disorder subjects, and may be used to assess treatment efficacy

Predicting brain age based on sleep EEG and DenseNet

We proposed a sleep EEG-based brain age prediction model which showed higher accuracy than previous models. Six-channel EEG data were acquired for 6 hours sleep. We then converted the EEG data into 2D scalograms, which were subsequently inputted to DenseNet used to predict brain age. We then evaluated the association between brain aging acceleration and sleep disorders such as insomnia and OSA.The correlation between chronological age and expected brain age through the proposed brain age prediction model was 80% and the mean absolute error was 5.4 years. The proposed model revealed brain age increases in relation to the severity of sleep disorders.In this study, we demonstrate that the brain age estimated using the proposed model can be a biomarker that reflects changes in sleep and brain health due to various sleep disorders.Clinical Relevance-Proposed brain age index can be a single index that reflects the association of various sleep disorders and serve as a tool to diagnose individuals with sleep disorders