Effects of ultraviolet weathering aging on the color stability and biocompatibility of various computer-aided design and computer-aided manufacturing glass-ceramic materials

OBJECTIVES

This study assessed the changes in color stability and biocompatibility of computer-aided design and computer-aided manufacturing (CAD-CAM) glass-ceramics after ultraviolet weathering (UW) aging.

METHODS

A total of 300 plate-shaped specimens (12.0 × 14.0 × 1.5 mm3) were prepared using a leucite-reinforced glass-ceramic (IPS Empress CAD; E), a lithium disilicate (IPS e.max CAD; M), and two zirconia-reinforced lithium silicate (Celtra Duo; C, Vita Suprinity; V) glass-ceramics. Specimens were divided into three groups (n = 25, each), subjected to water storage at 37 °C for 24 h (control group), or UW aging at 150 kJ/m2 (first-aged group) or 300 kJ/m2 (second-aged group). The color stability, mechanical and surface properties, and biocompatibility of the CAD-CAM glass-ceramics were investigated experimentally, followed by statistical analysis.

RESULTS

The brightness and redness or greenness were reduced in all groups after aging. After the first aging, V exhibited the largest color change and E exhibited the smallest color change. After the second aging, E exhibited the highest nanoindentation hardness and Young's modulus. The surface roughness was the highest for V after the first aging. Furthermore, the hydrophilicity of the materials increased after aging process. The cell proliferation/viability of human gingival fibroblasts was the highest in E before and after aging. Almost all cells survived for all groups based on a live/dead assay.

CONCLUSIONS

Leucite-reinforced glass-ceramic exhibit the highest color stability and biocompatibility after aging. The color stability and biocompatibility of CAD-CAM glass-ceramics depend on the aging process and material type.

CLINICAL SIGNIFICANCE

Various CAD-CAM glass-ceramics exhibit adequate color stability after UW aging. The leucite-reinforced glass-ceramics exhibit the highest color stability, cell proliferation, and viability after aging. The color stability, mechanical and surface properties, and biocompatibility of the glass-ceramics depend on the aging process and material type.

Kondo screening in a Majorana metal

Kondo impurities provide a nontrivial probe to unravel the character of the excitations of a quantum spin liquid. In the S = 1/2 Kitaev model on the honeycomb lattice, Kondo impurities embedded in the spin-liquid host can be screened by itinerant Majorana fermions via gauge-flux binding. Here, we report experimental signatures of metallic-like Kondo screening at intermediate temperatures in the Kitaev honeycomb material α-RuCl3 with dilute Cr3+ (S = 3/2) impurities. The static magnetic susceptibility, the muon Knight shift, and the muon spin-relaxation rate all feature logarithmic divergences, a hallmark of a metallic Kondo effect. Concurrently, the linear coefficient of the magnetic specific heat is large in the same temperature regime, indicating the presence of a host Majorana metal. This observation opens new avenues for exploring uncharted Kondo physics in insulating quantum magnets.

National prevalence and determinants of COVID-19 vaccine hesitancy during the initial phase pandemic

OBJECTIVE

Although previous studies have explored the causes of COVID-19 vaccine hesitancy during the pandemic, there is a lack of generality and reproducibility in these studies. Therefore, we aimed to comprehensively identify the determinants of COVID-19 vaccine hesitancy through a representative nationwide cross-sectional study conducted in South Korea.

SUBJECTS AND METHODS

We used a nationwide, representative, and large-scale dataset from the 2021 Community Health Survey. By analyzing 193,495 participants, we investigated the nationwide incidence of COVID-19 vaccine hesitancy and the various causes thereof.

RESULTS

The national prevalence of COVID-19 vaccine hesitancy was 5.7% (95% CI, 5.5-5.8). COVID-19 vaccine hesitancy was associated with an increased incidence of the following factors: (1) demographic factors including early-middle adulthood [vs. late; odds ratio (OR), 1.51; 95% CI, 1.38-1.65] and male sex (vs. female sex; OR, 1.08; 95% CI, 1.01-1.14); (2) physically healthy subjects; (3) lower socio-economic status (vs. high household income; OR, 1.28; 95% CI, 1.19-1.38); (4) having mental illness (vs. normal mental status; OR, 1.25; 95% CI, 1.13-1.38); and (5) unhealthy habits such as current smoking (vs. non-smoking; OR, 1.22; 95% CI, 1.13-1.31); and insufficient physical activity (vs. sufficient; OR, 1.08; 95% CI, 1.01-1.17). Common reasons for vaccine hesitancy were concerns about side effects (41.34%), health problems (24.60%), and inability to select the type of vaccine (14.13%).

CONCLUSIONS

This representative large-scale nationwide study conducted in South Korea investigated the nationwide prevalence and determinants of vaccine hesitancy. Our results provide useful public health information, especially on novel aspects of vaccination strategies, for policymakers to improve the acceptance of COVID-19 vaccines.

The Effects of Thermocycling on the Physical Properties and Biocompatibilities of Various CAD/CAM Restorative Materials

The purpose of this study is to evaluate the changes in physical properties and biocompatibilities caused by thermocycling of CAD/CAM restorative materials (lithium disilicate, zirconia reinforced lithium silicate, polymer-infiltrated ceramic network, resin nanoceramic, highly translucent zirconia). A total of 225 specimens were prepared (12.0 × 10.0 × 1.5 mm) and divided into three groups subjected to water storage at 37 °C for 24 h (control group), 10,000 cycles in distilled water at 5-55 °C (first aged group), and 22,000 cycles in distilled water at 5-55 °C (second aged group) [(n= 15, each]). The nanoindentation hardness and Young's modulus (nanoindenter), surface roughness (atomic force microscopy (AFM)), surface texture (scanning electron microscopy (FE-SEM)), elemental concentration (energy dispersive spectroscopy (EDS)) and contact angle were evaluated. The morphology, proliferation and adhesion of cultured human gingival fibroblasts (HGFs) were analyzed. The data were analyzed using one-way ANOVA and Tukey's test (p < 0.05). The results showed that the nanoindentation hardness and Young's modulus were decreased after thermocycling aging. Cell viability and proliferation of the material decreased with aging except for the highly translucent zirconia. Zirconia-reinforced lithium silicate exhibited significantly lower cell viability compared to other materials. The surface roughnesses of all groups increased with aging. Cell viability and Cell adhesion were influenced by various factors, including the surface chemical composition, hydrophilicity, surface roughness, and topography.

Evaluation of Implant Stability According to Implant Placement Site and Duration in Elderly Patients: A Prospective Multi-Center Cohort Study

The aim of this prospective study is to investigate implant stability and the reliability of different measuring devices according to implant placement site and duration in patients aged over 65 years. The study evaluated 60 implants (diameter: 3.5/4.0/4.5/5.0 mm and length: 8.5/10.0/11.5 mm) in 60 patients aged ≥ 65 years. The implant placement sites were divided into six evenly distributed sections (n = 10), i.e., maxillary right-posterior, A; maxillary anterior, B; maxillary left-posterior, C; mandibular right-posterior, D; mandibular anterior, E; mandibular left-posterior, F. Participants visited the hospital six times: implant surgery, 1V; stitch removal, 2V; 1-month follow-up, 3V; 2-month follow-up, 4V; before final restoration delivery, 5V; and after final restoration delivery, 6V. The implant stability was evaluated with the Osstell Mentor (ISQ), Periotest M (PTV), and Anycheck (IST). The mean values of ISQ, PTV, and IST were analyzed (α = 0.05). ISQ, PTV, and IST results of 4V and 5V were significantly higher than those of 1V (p < 0.05). The lowest ISQ results occurred in the E location at 4V and 5V (p < 0.05). In all mandibular locations, IST results of 6V were significantly higher than those of 1V, 2V, 3V, and 4V (p < 0.05). ISQ results were negatively correlated with PTV and positively correlated with IST, and PTV was negatively correlated with IST. By considering various factors affecting the stability of the implant, it is necessary to determine the appropriate implant load application time. This could help increase the implant success rate in elderly patients. And as a diagnostic device for implant stability and the evaluation of osseointegration in elderly patients, Anycheck was also able to prove its relative reliability compared to Osstell ISQ Mentor and Periotest M.

Risk factors for musculoskeletal-related occupational disability among US Army soldiers

INTRODUCTION

Minimising temporary and permanent disability associated with musculoskeletal conditions (MSK-D) is critical to the mission of the US Army. Prior research has identified potentially actionable risk factors for overall military disability and its MSK-D subset, including elevated body mass index, tobacco use and physical fitness. However, prior work does not appear to have addressed the impact of these factors on MSK-D when controlling for a full range of factors that may affect health behaviours, including aptitude scores that may serve as a proxy for health literacy. Identifying risk factors for MSK-D when providing control for all such factors may inform efforts to improve military readiness.

METHODS

We studied 494 757 enlisted Army soldiers from 2014 to 2017 using a combined medical and administrative database. Leveraging data from the Army's digital 'eProfile' system of duty restriction records, we defined MSK-D as the first restriction associated with musculoskeletal conditions and resulting in the inability to deploy or train. We used multivariable Cox proportional hazards regression to assess the associations between incident MSK-D and selected risk factors including aptitude scores, physical fitness test scores, body mass index and tobacco use.

RESULTS

Among the subjects, 281 278 (45.14%) experienced MSK-D. In the MSK-D hazards model, the highest effect size was for failing the physical fitness test (adjusted HR=1.63, 95% CI 1.58 to 1.67, p<0.001) compared with scoring ≥290 points.

CONCLUSIONS

The analysis revealed the strongest associations between physical fitness and MSK-D. Additional efforts are warranted to determine potential mechanisms for the observed associations between selected factors and MSK-D.

Implant stability changes over time following implant placement in elderly patients: A prospective study

OBJECTIVES

This study aimed to evaluate the effect of aging on the changes in implant stability over time following implant placement.

MATERIALS AND METHODS

A total of 104 patients in four age ranges (group 1: <60 years, group 2: 61-70 years, group 3: 71-80 years, and group 4: >80 years) were included. Bone-level tapered implants were placed without implementing any bone augmentation procedure. The final torque value displayed on the implant engine during implant insertion was recorded. Cone-beam computed tomography (CBCT) was performed immediately after surgery to analyze the bone quality around the implant. Implant stability was measured immediately after surgery and 2, 4, and 8 weeks after surgery.

RESULTS

In the CBCT image, higher grayscale values were observed in the order of group 1, group 2, and groups 3/4, with statistical significance (p < .05). There was no significant difference in the insertion torque values between age groups (p ≥ .05). Groups 1 and 2 showed lower implant stability values after 2 and 4 weeks compared to immediately and 8 weeks after surgery (p < .05); however, groups 3 and 4 showed no significant difference between the results measured at different timepoints (p ≥ .05).

CONCLUSIONS

Implant treatment in elderly patients is successful showing a settled implant stability over time following implant placement when the implant is appropriately engaged in the alveolar bone in the absence of bone augmentation.

Implementation of CAD/CAM program in a nonface-to-face classroom environment due to the COVID-19 pandemic

PURPOSE/OBJECTIVES

This study aimed to evaluate a nonface-to-face crown designing module in a preclinical dental course.

METHODS

Free dental planning software (Blue Sky Plan) was installed on the personal computers of dental college students, and a #46 full veneer crown designing practice was performed individually. An online survey was conducted on the computers' specification and main usage of the students, the practice process, and results. Statistical analysis was conducted to analyze the association between variables, such as "operating system," "central processing unit ," "number of cores," "random-access memory (RAM)," "graphic card," and task performance.

RESULTS

Of the D2 students, 75.4% (52 of 69) responded to the survey. Overall, 96% of the respondents used their computers, and all respondents had no problem running the program. Most of the students marked their level of computer literacy as intermediate and had purchased the computers for the purpose of performing light work. The most common specifications of the computer were Intel i5, quad core, 8 GB RAM, and Windows 10. Students had little experience with computer-aided design/computer-aided manufacturing before the class. The relationship between computer specifications and task performance was not statistically significant.

CONCLUSIONS

Overall, students with intermediate-level computer literacy used computers with less than the recommended specifications of the program; however, they were able to run the program and individually proceed with modules to submit results. Using an individually available crown designing program can provide an opportunity to diversify curricula and broaden students' perspectives even under circumstances like the COVID-19 pandemic that limits intimate face-to face classes.

17-year trends of body mass index, overweight, and obesity among adolescents from 2005 to 2021, including the COVID-19 pandemic: a Korean national representative study

OBJECTIVE

There is a lack of pediatric studies that have analyzed trends in mean body mass index (BMI) and the prevalence of obesity and overweight over a period that includes the mid-stage of the COVID-19 pandemic. Thus, we aimed to investigate trends in BMI, overweight, and obesity among Korean adolescents from 2005 to 2021, including the COVID-19 pandemic.

SUBJECTS AND METHODS

We used data from the Korea Youth Risk Behavior Web-based Survey (KYRBS), which is nationally representative of South Korea. The study included middle- and high-school students between the ages of 12 and 18. We examined trends in mean BMI and prevalence of obesity and/or overweight during the COVID-19 pandemic and compared these to those of pre-pandemic trends in each subgroup by gender, grade, and residential region.

RESULTS

Data from 1,111,300 adolescents (mean age: 15.04 years) were analyzed. The estimated weighted mean BMI was 20.48 kg/m2 (95% CI, 20.46-20.51) between 2005 and 2007, and this was 21.61 kg/m2 (95% CI, 21.54-21.68) in 2021. The prevalence of overweight and obesity was 13.1% (95% CI, 12.9-13.3%) between 2005 and 2007 and 23.4% (95% CI, 22.8-24.0%) in 2021. The mean BMI and prevalence of obesity and overweight have gradually increased over the past 17 years; however, the extent of change in mean BMI and in the prevalence of obesity and overweight during the pandemic was distinctly less than before. The 17-year trends in the mean BMI, obesity, and overweight exhibited a considerable rise from 2005 to 2021; however, the slope during the COVID-19 pandemic (2020-2021) was significantly less prominent than in the pre-pandemic (2005-2019).

CONCLUSIONS

These findings enable us to comprehend long-term trends in the mean BMI of Korean adolescents and further emphasize the need for practical prevention measures against youth obesity and overweight.

Ion beam figuring with focused anode layer thruster

This work presents the peculiarities of cone ion beam formation with a focused thruster with anode layer (TAL) and its application to silicon carbide (SiC) ion beam figuring. Modeling results of Lorentz E × B force distribution in the discharge gap are presented. 3D particle tracing for keV Ar ions is carried out for the first time in the beam drift region of TAL with magnetic lens. Extracted ion beam full width at half maxima is about 2 mm in the focal plane, where the SiC etching rate reaches 0.5 µm/min. The SiC sputter yields are measured as a function of the Ar ion impact energy and beam incidence angle. The maximum sputter yield of 2.8 atom/ion is observed at 45° of the beam-sample angle for the Si targets. Furthermore, the maximum sputter yield value of 1.7 atom/ion is measured at 30° of the beam-sample angle for the SiC targets. The novelty of present research is in the application of focused TAL keV Ar ion beam to the SiC ion beam figuring.

[MUC4 Silencing Inhibits TGF-β1-induced Epithelial-mesenchymal Transition VIA the ERK1/2 Pathway in Human Airway Epithelial NCI-H292 Cells]

MUC4 is a predominant membrane-tethered mucin lubricating and protecting the epithelial surface and playing various biological roles in the renewal and differentiation of epithelial cells, cell signaling, cell adhesion, and carcinogenesis. Interestingly, recent studies have demonstrated that MUC4 expression regulates the epithelial-mesenchymal transition (EMT) of cancer cells in ovarian, pancreatic, and lung cancer. However, the effects of MUC4 expression on EMT in human airway epithelial cells are not yet well known. Here, we describe the effects of transforming growth factor beta 1 (TGF-β1)-induced MUC4 expression on EMT and evaluate its downstream signaling pathway in human airway epithelial cells. In human airway epithelial NCI-H292 cells, exposure to TGF-β1 induced expression of MUC4, CDH2, VIM and SNAI1 genes and encoded by them proteins, MUC4, N-cadherin, vimentin and Snail, and reduced the level of CDH1 and its product, E-cadherin. In MUC4-knockdown cells, TGF-β1-induced expression levels of MUC4, CDH2, VIM and SNAI1 and corresponding proteins were suppressed, but CDH1 and E-cadherin levels were not. In addition, TGF-β1-induced phosphorylation of extracellular signal regulated kinase 1/2 (ERK1/2) was suppressed, but that of Smad2/3, Akt, and p38 was not. The results of this study suggest that MUC4 silencing inhibits TGF-β1 -induced EMT via the ERK1/2 pathway, and a possible role of MUC4 in the induction of EMT in human airway epithelial cells.

Timing and clinical outcomes of tracheostomy in patients with COVID-19

In this retrospective multicentre cohort study that included 27 COVID-19 patients who underwent tracheostomy, the mean time between intubation and tracheostomy was 15.8 days and the negative conversion time of COVID-19 was 43.1 days. Eleven patients (40.7%) died of COVID-19 and the use of percutaneous dilatation tracheostomy was significantly associated with in-hospital death. Timely tracheostomy could be performed in COVID-19 patients, regardless of duration of intubation or positivity of COVID-19 test, with an open surgical tracheostomy as a preferable technique.

Effects of thermal and mechanical cycling on the mechanical strength and surface properties of dental CAD-CAM restorative materials

STATEMENT OF PROBLEM

The properties of dental computer-aided design and computer-aided manufacturing (CAD-CAM) materials vary. Studies regarding the effects of aging on the properties of these materials are lacking.

PURPOSE

The purpose of this in vitro study was to evaluate the changes in the mechanical and surface properties of different CAD-CAM materials after thermocycling and mechanical loading.

MATERIAL AND METHODS

In total, 150 bar-shaped specimens (17.0×4.0×2.0 mm) were prepared from feldspathic glass-ceramic (VM; Vitablocs Mark II), lithium disilicate glass-ceramic (EX; IPS e.max CAD), zirconia-reinforced lithium silicate glass-ceramic (CD; Celtra Duo), polymer-infiltrated ceramic network (VE; Vita Enamic), and resin-nanoceramic (CS; Cerasmart). Each type was divided into 2 groups (n=15; each). One group was subjected to thermocycling in distilled water at 5 °C to 55 °C for 6000 cycles and 50 N mechanical loading for 1.2×10⁶ cycles. The other group was stored in 37 °C water for 24 hours. Nanoindentation hardness, Young modulus, and 3-point flexural strength were measured for the analyses of the mechanical properties. Surface roughness, surface microstructure, and elemental composition were measured to analyze the surface characteristics. Statistical analyses were performed with 1-way ANOVA with the Tukey HSD post hoc test, independent samples t test, Kruskal-Wallis test with Bonferroni post hoc test, Mann-Whitney U test, and 2-way ANOVA (α=.05).

RESULTS

Before and after aging, CS exhibited the lowest hardness (1.20 to 1.04 GPa) and Young modulus (13.76 to 13.48 GPa) values (P<.05). EX exhibited the highest flexural strengths (393.43 to 391.86 MPa), and VM exhibited the lowest (109.98 to 112.73 MPa) values (P<.05). CS exhibited the highest surface roughness (S_a and S_q; 10.60 to 28.82, 14.21 to 38.27 nm) values (P<.05). After aging, the hardness and Young modulus of VM, EX, and VE decreased significantly (P<.001). No significant difference was observed in the flexural strengths of the CAD-CAM materials (P>.05). Significant increases were observed in the surface roughness of all the materials (P<.05), with altered microstructures. Except for the flexural strength, the mechanical properties and surface characteristics of the CAD-CAM materials were significantly affected by the material type after aging.

CONCLUSIONS

Before and after aging, resin-nanoceramic exhibited the lowest hardness and Young modulus, and the highest surface roughness. Lithium disilicate glass-ceramic exhibited the highest flexural strength and feldspathic glass-ceramic exhibited the lowest value. After aging, increased surface roughness and microstructure alterations were observed. Significant interactions between aging process and material type were found for the mechanical properties and surface characteristics except for the flexural strength.

Evaluation of the response of esthetic restorative materials to ultraviolet aging

STATEMENT OF PROBLEM

The optical properties of esthetic computer-aided design and computer-aided manufacturing (CAD-CAM) materials can change depending on the clinical situation. Studies that compare esthetic CAD-CAM materials based on their optical properties are lacking.

PURPOSE

The purpose of this in vitro study was to evaluate the optical properties of esthetic CAD-CAM specimens after ultraviolet (UV) aging based on the type and thickness of the material.

MATERIAL AND METHODS

In total, 240 plate-shaped specimens (14×12×1 mm and 14×12×2 mm) of a nanohybrid composite resin (Tetric CAD), a fine-structure feldspathic ceramic (Vitablocs Mark II), 2 different glass-ceramics (IPS Empress CAD and IPS e.max CAD), a zirconia-reinforced lithium silicate glass-ceramic (Celtra Duo), a polymer-infiltrated ceramic network (Vita Enamic), and 2 different resin nanoceramics (Cerasmart and Lava Ultimate) were fabricated (n=15). The optical parameters were analyzed by spectrophotometry before and after UV aging. The brightness (L∗), red green (a∗), yellow-blue (b∗), chroma (Ch), and hue (h) were measured, and the color difference (ΔE₀₀) values were calculated. The translucency parameter (TP), total transmittance (Tt), and contrast ratio (CR) were also determined. Statistical analyses were performed with 1-way ANOVA, the Tukey honestly significant difference post hoc test, independent- and paired-samples t tests, and 2-way ANOVA (α=.05).

RESULTS

Significant interactions were observed for the aging process, material type, and thickness for all optical parameters (P<.05). L∗, TP, and Tt had lower values, while CR had higher values for the aging group than that of the control group (P<.05). The h, TP, and Tt values were higher, whereas the b∗ and CR values were lower for the 1-mm group than those of the 2-mm group (P<.05). The highest ΔE₀₀ value was found in the Lava Ultimate 1-mm group (ΔE₀₀=3.21) and 2-mm group (ΔE₀₀=2.42). The lowest ΔE₀₀ value was found in the Vitablocs Mark II 1-mm group (ΔE₀₀=0.31). The highest TP and Tt and the lowest CR values were observed for Tetric CAD; the lowest TP and Tt, and the highest CR values were noted in Celtra Duo (P<.05).

CONCLUSIONS

The optical properties of the CAD-CAM specimens were affected by the aging process, material type, and thickness, and the color stability was clinically applicable in all CAD-CAM materials except groups Lava Ultimate and Cerasmart(ΔE₀₀<2.25). Resin nanoceramics exhibited the greatest color changes after UV aging, and a 2-mm thickness is recommended to ensure acceptable color stability. The zirconia-reinforced lithium silicate glass-ceramic was the most opaque, with a 1-mm thickness providing increased translucency.

Fipronil upregulates inflammatory cytokines and MUC5AC expression in human nasal epithelial cells

BACKGROUND

Airway inflammation and excessive mucin production are pathophysiological characteristics of airway diseases. Fipronil, a pesticide, is being extensively used in agriculture and veterinary medicine worldwide. However, this compound impairs immune function in non-target organisms. The present study aimed to evaluate the effect of fipronil on pro-inflammatory cytokine and mucus production and signalling pathways in human primary nasal METHODOLOGY: The effect of fipronil on pro-inflammatory cytokine and MUC5AC expression and the signalling pathway of fipronil were investigated using real-time PCR, enzyme immunoassays, immunofluorescence, and immunoblot analysis with specific inhibitors and small interfering RNA.

RESULTS

Fipronil treatment increased pro-inflammatory cytokine interleukin (IL)-1beta, IL-6, IL-8, and MUC5AC expression in human primary nasal epithelial cells. It also induced phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) mitogenactivated protein kinase (MAPK), p38 MAPK, and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB). MAPK and NF-kB inhibitor treatment significantly inhibited increases in IL-1beta, IL-6, IL-8, and MUC5AC expression. Ex vivo data confirmed that fipronil-induced MUC5AC expression occurs through ERK1/2, p38, and NF-kB signalling pathways in nasal inferior turbinate tissue.

CONCLUSIONS

Fipronil induced pro-inflammatory cytokine IL-1beta, IL-6, IL-8, and MUC5AC expression via ERK1/2 MAPK, p38 MAPK, and NF-kB in human primary nasal epithelial cells.

Randomly Hopping Majorana Fermions in the Diluted Kitaev System α-Ru_{0.8}Ir_{0.2}Cl_{3}

dc and ac magnetic susceptibility, magnetization, specific heat, and Raman scattering measurements are combined to probe low-lying spin excitations in α-Ru_{1-x}Ir_{x}Cl_{3} (x≈0.2), which realizes a disordered spin liquid. At intermediate energies (ℏω>3  meV), Raman spectroscopy evidences linearly ω-dependent Majorana-like excitations, obeying Fermi statistics. This points to robustness of a Kitaev paramagnetic state under spin vacancies. At low energies below 3 meV, we observe power-law dependences and quantum-critical-like scalings of the thermodynamic quantities, implying the presence of a weakly divergent low-energy density of states. This scaling phenomenology is interpreted in terms of the random hoppings of Majorana fermions. Our results demonstrate an emergent hierarchy of spin excitations in a diluted Kitaev honeycomb system subject to spin vacancies and bond randomness.

Exotic Low-Energy Excitations Emergent in the Random Kitaev Magnet Cu_{2}IrO_{3}

We report on magnetization M(H), dc and ac magnetic susceptibility χ(T), specific heat C_{m}(T) and muon spin relaxation (μSR) measurements of the Kitaev honeycomb iridate Cu_{2}IrO_{3} with quenched disorder. In spite of the chemical disorders, we find no indication of spin glass down to 260 mK from the C_{m}(T) and μSR data. Furthermore, a persistent spin dynamics observed by the zero-field muon spin relaxation evidences an absence of static magnetism. The remarkable observation is a scaling relation of χ[H,T] and M[H,T] in H/T with the scaling exponent α=0.26-0.28, expected from bond randomness. However, C_{m}[H,T]/T disobeys the predicted universal scaling law, pointing towards the presence of additional low-lying excitations on the background of bond-disordered spin liquid. Our results signify a many-faceted impact of quenched disorder in a Kitaev spin system due to its peculiar bond character.

Gender differences in limited duty time for lower limb injury

Background

Among active-duty military personnel, lower limb musculoskeletal injuries and related conditions (injuries) frequently arise as unintended consequences of physical training. These injuries are particularly common among women. The practical impact of such injuries on temporary military occupational disability has not been estimated with precision on a large scale.

Aims

To determine the proportion of service time compromised by limited duty days attributable to lower limb injuries, characterize the time affected by these limitations in terms of specific lower limb region and compare the limited duty time between male and female soldiers.

Methods

Administrative data and individual limited duty assignments (profiles) were obtained for active-duty US Army personnel who served in 2014. Lower limb injury-related profiles were used to calculate the percent of person-time requiring duty limitations by gender and body region.

Results

The study group was 568 753 soldiers of whom 14% were women. Nearly 13% of service days for active-duty US Army soldiers required limited duty for lower limb injuries during 2014. Knee injuries were responsible for 45% of those days. Within integrated military occupations, female soldiers experienced 27-57% more time on limited duty for lower limb injuries compared with men.

Conclusions

The substantial amount of limited duty for lower limb musculoskeletal injuries among soldiers highlights the need for improvement in training-related injury screening, prevention and timely treatment with particular attention to knee injuries. The excessive impact of lower limb injuries on female soldiers' occupational functions should be a surveillance priority in the current environment of expanding gender-integrated training.

Identification of transfusion-transmitted hepatitis A through postdonation information in Korea: results of an HAV lookback (2007-2012)

BACKGROUND AND OBJECTIVES

Despite safety measures to minimize the risk of transfusion-transmitted infections, a residual risk remains. To trace and review some such cases, we ask donors to notify the blood centre if they are diagnosed with an infection after they donate blood.

MATERIALS AND METHODS

We analysed all data on postdonation cases of hepatitis A reported between 2007 and 2012. Archived specimens from these donors were tested for hepatitis A virus (HAV) using anti-HAV IgM/IgG and HAV-PCR as markers. If any of the test results were positive, we reviewed the medical records of the recipients and, if necessary, tested them for hepatitis A.

RESULTS

Fifteen blood donors notified the blood centres of having been diagnosed with hepatitis A after donation. All archived samples except for one were HAV-PCR-positive and anti-HAV IgM/IgG-negative. Of the donated components, four RBCs and 14 FFPs had not been transfused to patients and were recalled. Among 26 recipients of the implicated components, fourteen were still alive when they were notified. Two patients showed clinical symptoms of hepatitis A and had positive results with anti-HAV IgM.

CONCLUSION

Transfusion-transmitted hepatitis A is rare but exists. To reduce the risk, donors should be told to notify the blood centre if they are diagnosed with blood-borne diseases after they donate blood. Physicians should consider the possibility of transfusion-transmitted hepatitis A if a transfused patient has hepatitis A but no history of travel or route of faecal-oral infection.

Whole-Tumor Histogram and Texture Analyses of DTI for Evaluation of IDH1-Mutation and 1p/19q-Codeletion Status in World Health Organization Grade II Gliomas

BACKGROUND AND PURPOSE

Prediction of the isocitrate dehydrogenase 1 (IDH1)-mutation and 1p/19q-codeletion status of World Health Organization grade ll gliomas preoperatively may assist in predicting prognosis and planning treatment strategies. Our aim was to characterize the histogram and texture analyses of apparent diffusion coefficient and fractional anisotropy maps to determine IDH1-mutation and 1p/19q-codeletion status in World Health Organization grade II gliomas.

MATERIALS AND METHODS

Ninety-three patients with World Health Organization grade II gliomas with known IDH1-mutation and 1p/19q-codeletion status (18 IDH1 wild-type, 45 IDH1 mutant and no 1p/19q codeletion, 30 IDH1-mutant and 1p/19q codeleted tumors) underwent DTI. ROIs were drawn on every section of the T2-weighted images and transferred to the ADC and the fractional anisotropy maps to derive volume-based data of the entire tumor. Histogram and texture analyses were correlated with the IDH1-mutation and 1p/19q-codeletion status. The predictive powers of imaging features for IDH1 wild-type tumors and 1p/19q-codeletion status in IDH1-mutant subgroups were evaluated using the least absolute shrinkage and selection operator.

RESULTS

Various histogram and texture parameters differed significantly according to IDH1-mutation and 1p/19q-codeletion status. The skewness and energy of ADC, 10th and 25th percentiles, and correlation of fractional anisotropy were independent predictors of an IDH1 wild-type in the least absolute shrinkage and selection operator. The area under the receiver operating curve for the prediction model was 0.853. The skewness and cluster shade of ADC, energy, and correlation of fractional anisotropy were independent predictors of a 1p/19q codeletion in IDH1-mutant tumors in the least absolute shrinkage and selection operator. The area under the receiver operating curve was 0.807.

CONCLUSIONS

Whole-tumor histogram and texture features of the ADC and fractional anisotropy maps are useful for predicting the IDH1-mutation and 1p/19q-codeletion status in World Health Organization grade II gliomas.

Prediction of IDH1-Mutation and 1p/19q-Codeletion Status Using Preoperative MR Imaging Phenotypes in Lower Grade Gliomas

BACKGROUND AND PURPOSE

WHO grade II gliomas are divided into three classes: isocitrate dehydrogenase (IDH)-wildtype, IDH-mutant and no 1p/19q codeletion, and IDH-mutant and 1p/19q-codeleted. Different molecular subtypes have been reported to have prognostic differences and different chemosensitivity. Our aim was to evaluate the predictive value of imaging phenotypes assessed with the Visually AcceSAble Rembrandt Images lexicon for molecular classification of lower grade gliomas.

MATERIALS AND METHODS

MR imaging scans of 175 patients with lower grade gliomas with known IDH1 mutation and 1p/19q-codeletion status were included (78 grade II and 97 grade III) in the discovery set. MR imaging features were reviewed by using Visually AcceSAble Rembrandt Images (VASARI); their associations with molecular markers were assessed. The predictive power of imaging features for IDH1-wild type tumors was evaluated using the Least Absolute Shrinkage and Selection Operator. We tested the model in a validation set (40 subjects).

RESULTS

Various imaging features were significantly different according to IDH1 mutation. Nonlobar location, larger proportion of enhancing tumors, multifocal/multicentric distribution, and poor definition of nonenhancing margins were independent predictors of an IDH1 wild type according to the Least Absolute Shrinkage and Selection Operator. The areas under the curve for the prediction model were 0.859 and 0.778 in the discovery and validation sets, respectively. The IDH1-mutant, 1p/19q-codeleted group frequently had mixed/restricted diffusion characteristics and showed more pial invasion compared with the IDH1-mutant, no codeletion group.

CONCLUSIONS

Preoperative MR imaging phenotypes are different according to the molecular markers of lower grade gliomas, and they may be helpful in predicting the IDH1-mutation status.

Morphometric analysis of the maxillary root apex positions according to crowding severity

OBJECTIVES

To determine differences in arch forms derived from the root apices locations between individuals with <2 mm maxillary crowding and controls.

SETTING AND SAMPLE POPULATION

The Department of Orthodontics, Pusan National University. Cone-beam computed tomography (CBCT) images of 102 patients in the control group and 95 patients in the crowding group.

MATERIALS AND METHODS

X, Y and Z coordinates of the tip of the crowns and the apex of the root of the maxillary teeth (except second molars) were determined on the CBCT images. The acquired three-dimensional (3D) coordinates were converted into two-dimensional (2D) coordinates via projection on the palatal plane, and the Procrustes analysis was employed to process the converted 2D coordinates. The mean shape of the arch form derived from the location of the tip of the crowns and the apex of the root was compared between groups using the statistical shape analysis.

RESULTS

There was a statistically significant difference (P = .046) between the groups for the mean shape of the root apex arch form, but the difference was small and clinically irrelevant as it is minor compared to the degree of crowding.

CONCLUSIONS

Maxillary arch from at the level of the maxillary apices only shows minor differences between crowded and non-crowded dentitions.

The Initial Area Under the Curve Derived from Dynamic Contrast-Enhanced MRI Improves Prognosis Prediction in Glioblastoma with Unmethylated MGMT Promoter

BACKGROUND AND PURPOSE

Although perfusion and permeability MR parameters have known to have prognostic value, they have reproducibility issues. Our aim was to evaluate whether the initial area under the time-to-signal intensity curve (IAUC) derived from dynamic contrast-enhanced MR imaging can improve prognosis prediction in patients with glioblastoma with known MGMT status.

MATERIALS AND METHODS

We retrospectively examined 88 patients with glioblastoma who underwent preoperative dynamic contrast-enhanced MR imaging. The means of IAUC values at 30 and 60 seconds (IAUC30_mean and IAUC60_mean) were extracted from enhancing tumors. The prognostic values of IAUC parameters for overall survival and progression-free survival were assessed with log-rank tests, according to the MGMT status. Multivariate overall survival and progression-free survival models before and after adding the IAUC parameters as covariates were explored by net reclassification improvement after receiver operating characteristic analysis for 1.5-year overall survival and 1-year progression-free survival and by random survival forest.

RESULTS

High IAUC parameters were associated with worse overall survival and progression-free survival in the unmethylated MGMT group, but not in the methylated group. In the unmethylated MGMT group, 1.5-year overall survival and 1-year progression-free survival prediction improved significantly after adding IAUC parameters (overall survival area under the receiver operating characteristic curve, 0.86; progression-free survival area under the receiver operating characteristic curve, 0.74-0.76) to the model with other prognostic factors (overall survival area under the receiver operating characteristic curve, 0.81; progression-free survival area under the receiver operating characteristic curve, 0.69; P < .05 for all) except in the case of IAUC60_mean for 1-year progression-free survival prediction (P = .059). Random survival forest models indicated that the IAUC parameters were the second or most important predictors in the unmethylated MGMT group, except in the case of the IAUC60_mean for progression-free survival.

CONCLUSIONS

IAUC can be a useful prognostic imaging biomarker in patients with glioblastoma with known MGMT status, improving prediction of glioblastoma prognosis with the unmethylated MGMT promoter status.

The effect of Korean-group cognitive behavioural therapy among patients with panic disorder in clinic settings

WHAT IS KNOWN ON THE SUBJECT?: Panic disorder patients display various panic-related physical symptoms and catastrophic misinterpretation of bodily sensations, which lower their quality of life by interfering with daily activities. Cognitive behavioural therapy (CBT) is a useful strategy for panic disorder patients to manage symptoms associated with inaccurate cognitive interpretation of situations resulting from the patient's cognitive vulnerability. In South Korea, however, despite the increasing prevalence of panic disorder, CBT is not a common element of nursing care plans for panic disorder patients. Moreover, few Korean researchers have attempted to assess the effects of CBT on such patients. WHAT THIS PAPER ADD TO EXISTING KNOWLEDGE?: In a strategy combining CBT and routine treatments, patients with panic disorder can experience greater positive effects in the acute treatment phase than those they experience when receiving only routine treatment. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: Mental health professionals, especially psychiatric nurses in local clinics who operate most special mental health programmes for panic disorder patients, should apply a panic disorder management programme that integrates CBT and routine treatments. The integrated approach is more effective for reducing the number of panic attacks and cognitive misinterpretation in patients than providing routine treatment alone. For patients with panic disorder, the objective of CBT is to understand the relationship between psychological panic disorder sensations, emotions, thoughts and behaviours. Therefore, nurses can help patients address and improve biological, social and psychological aspects of physical health problems as well as help them improve their coping skills in general.

ABSTRACT

Introduction In panic disorder, sensitivity to bodily sensations increases due to the patient's cognitive vulnerability. Cognitive behavioural therapy (CBT) can help to decrease sensitivity to bodily sensations by correcting these cognitive distortions by controlling negative thoughts and panic attacks. Aims This study verified whether group CBT is more effective than treatment as usual (TAU) in South Korean patients with panic disorder. Methods The study participants consisted of 76 panic disorder patients. Patients in the therapy condition attended sessions once a week for a total of 12 sessions in addition to drug treatment. Results In the therapy condition, there were significant decreases in panic-related bodily sensations and ranking and belief scores for catastrophic misinterpretation of external events. Discussion Group CBT, in comparison to TAU, decreases panic and agoraphobia symptom severity in South Korean patients with panic disorder. Our study provides evidence for the effectiveness of a panic disorder management programme that integrates group CBT and traditional pharmacotherapeutic treatment for patients with panic disorder. Implications for Practice The cognitive behavioural approach is needed to reduce panic and agoraphobia symptoms for hospitalized patients with panic disorder more than activity therapies, medications and supportive counselling by doctors and nurses.

Associations of dietary calcium intake with metabolic syndrome and bone mineral density among the Korean population: KNHANES 2008-2011

Excessive amount of calcium intake increased risk for metabolic syndrome in men. However, modest amount decreased the risk of metabolic syndrome and osteoporosis in postmenopausal women. Modest amount of calcium also increased bone mineral density (BMD) in both men and postmenopausal women.

INTRODUCTION

The present study aimed to evaluate the associations of dietary calcium intake with metabolic syndrome and bone mineral density (BMD) in Korean men and women, especially postmenopausal women.

METHODS

The study was performed using data from the Korean National Health and Nutrition Examination Survey (2008-2011) and included 14,705 participants (5953 men, 4258 premenopausal women, and 4494 postmenopausal women). Clinical and other objective characteristics, presence of metabolic syndrome, and the BMD of the femur neck and lumbar spine were evaluated according to dietary calcium intake.

RESULTS

There was a higher tendency for metabolic syndrome in men with a dietary calcium intake of >1200 mg/day than with ≤400 mg of calcium intake; >400 and ≤800 mg of calcium intake was helpful for postmenopausal women to decrease risk for metabolic syndrome. Overall, the group with calcium intake >400 and ≤800 mg daily had significantly increased BMD in both femoral neck and lumbar spine from both men and postmenopausal women. From both femoral neck and lumbar spine, the prevalence of osteoporosis in postmenopausal women significantly decreased in the group whose calcium intake was >400 and ≤800 mg daily.

CONCLUSION

Excessive dietary calcium may increase the prevalence of metabolic syndrome in men. For postmenopausal women, calcium intake does not increase the risk of metabolic syndrome, but modest amount decreases the risk. It may increase the BMD in men and postmenopausal women, and also reduce the prevalence of both osteoporosis and metabolic syndrome in postmenopausal women.

An effective diagnostic strategy for accurate detection of RhD variants including Asian DEL type in apparently RhD-negative blood donors in Korea

BACKGROUND AND OBJECTIVES

The purpose of this study was to provide an effective RHD genotyping strategy for the East Asian blood donors.

MATERIAL AND METHODS

RhD phenotyping, weak D testing and RhCE phenotyping were performed on 110 samples from members of the RhD-negative club, private organization composed of RhD-negative blood donors, in the GwangJu-Chonnam region of Korea. The RHD promoter, intron 4, and exons 7 and 10 were analysed by real-time PCR. Two nucleotide changes (c.1227 G>A, and c.1222 T>C) in exon 9 were analysed by sequencing.

RESULTS

Of 110 RhD-negative club members, 79 (71·8%) showed complete deletion of the RHD gene, 10 (9·1%) showed results consistent with RHD-CE-D hybrid, and 21 (19·1%) showed amplification of RHD promoter, intron 4, and exons 7 and 10. Of the latter group, 16 (14·5%) were in the DEL blood group including c.1227 G>A (N = 14) and c.1222 T>C (N = 2), 2 (1·8%) were weak D, 1(0·9%) was partial D, and 2 (1·8%) were undetermined. The RhD-negative phenotype samples consisted of 58 C-E-c+e+, 19 C-E+c+e+, 3 C-E+c+e-, 21 C+E-c+e-, 6 C+E-c+e+ and 3 C+E-c-e + . Notably, all 58 samples with the C-E-c+e+ phenotype were revealed to have complete deletion of the RHD gene. The C-E-c+e+ phenotype showed 100% positive predictive value for detecting D-negative cases.

CONCLUSIONS

RHD genotyping is not required in half of D-negative cases. We suggest here an effective RHD genotyping strategy for accurate detection of RhD variants in apparently RhD-negative blood donors in East Asia.

The effect of prolonged breast-feeding on the development of postmenopausal osteoporosis in population with insufficient calcium intake and vitamin D level

Breast-feeding affects bone metabolism and calcium homeostasis, and prolonged breast-feeding may influence the development of postmenopausal osteoporosis, particularly in highly susceptible populations. The study determined that breast-feeding may be a risk factor for postmenopausal osteoporosis, especially in people with low calcium intakes and vitamin D deficiencies.

INTRODUCTION

The purpose of this study was to determine whether breast-feeding is a risk factor in the development of postmenopausal osteoporosis, especially in highly susceptible population.

METHODS

The study was performed using data from the 2010 to 2011 Korea National Health and Nutrition Examination Survey, and it included 1231 postmenopausal women who were aged between 45 and 70 years. Osteoporosis was defined using the World Health Organization's T-score criteria, namely, a T-score of ≤-2.5 at the femoral neck or the lumbar spine. The patients' ages, body mass indexes, daily calcium intakes, serum vitamin D levels, exercise levels, smoking histories, and reproductive factors relating to menarche, menopause, delivery, breast-feeding, hormone treatment, and oral contraceptive use were evaluated. Comparisons between the osteoporosis and non-osteoporosis groups were undertaken using Student's t test and the chi-square test, and logistic regression models were built.

RESULTS

A significant increase in the risk of osteoporosis was apparent in postmenopausal women with prolonged breast-feeding histories (≥24 months) (model 1: odds ratio [OR] = 2.489; 95 % confidence interval [CI] = 1.111 to 5.578, p = 0.027; model 2: OR = 2.503; 95 % CI = 1.118 to 5.602, p = 0.026; model 3: OR = 2.825; 95 % CI = 1.056 to 7.56, p = 0.039), particularly in those with inadequate serum vitamin D levels and calcium intakes (<800 mg/day).

CONCLUSIONS

Breast-feeding seems to increase the risk of postmenopausal osteoporosis; however, its impact may not be definitive in women with sufficient vitamin D levels and calcium intakes. Therefore, sufficient calcium intakes and adequate vitamin D levels may be important to prevent osteoporosis in postmenopausal women that is derived from breast-feeding.

Microtensile bond strength and micromorphologic analysis of surface-treated resin nanoceramics

PURPOSE

The aim of this study was to evaluate the influence of different surface treatment methods on the microtensile bond strength of resin cement to resin nanoceramic (RNC).

MATERIALS AND METHODS

RNC onlays (Lava Ultimate) (n=30) were treated using air abrasion with and without a universal adhesive, or HF etching followed by a universal adhesive with and without a silane coupling agent, or tribological silica coating with and without a universal adhesive, and divided into 6 groups. Onlays were luted with resin cement to dentin surfaces. A microtensile bond strength test was performed and evaluated by one-way ANOVA and Tukey HSD test (α=.05). A nanoscratch test, field emission scanning electron microscopy, and energy dispersive X-ray spectroscopy were used for micromorphologic analysis (α=.05). The roughness and elemental proportion were evaluated by Kruskal–Wallis test and Mann–Whitney U test.

RESULTS

Tribological silica coating showed the highest roughness, followed by air abrasion and HF etching. After HF etching, the RNC surface presented a decrease in oxygen, silicon, and zirconium ratio with increasing carbon ratio. Air abrasion with universal adhesive showed the highest bond strength followed by tribological silica coating with universal adhesive. HF etching with universal adhesive showed the lowest bond strength.

CONCLUSION

An improved understanding of the effect of surface treatment of RNC could enhance the durability of resin bonding when used for indirect restorations. When using RNC for restoration, effective and systemic surface roughening methods and an appropriate adhesive are required.

A study on the changes in attractive force of magnetic attachments for overdenture

PURPOSE

Although magnetic attachment is used frequently for overdenture, it is reported that attractive force can be decreased by abrasion and corrosion. The purpose of this study was to establish the clinical basis about considerations and long term prognosis of overdenture using magnetic attachments by investigating the change in attractive force of magnetic attachment applied to the patients.

MATERIALS AND METHODS

Among the patients treated with overdenture using magnetic attachments in Dankook University Dental Hospital, attractive force records of 61 magnetic attachments of 20 subjects who re-visited from July 2013 to June 2014 were analyzed. Dental magnet tester (Aichi Micro Intelligent Co., Aichi, Japan) was used for measurement. The magnetic attachments used in this study were Magfit IP-B Flat, Magfit DX400, Magfit DX600 and Magfit DX800 (Aichi Steel Co., Aichi, Japan) filled with Neodymium (NdFeB), a rare-earth magnet.

RESULTS

Reduction ratio of attractive force had no significant correlation with conditional variables to which attachments were applied, and was higher when the maintenance period was longer (P<.05, r=.361). Reduction ratio of attractive force was significantly higher in the subject group in which attachments were used over 9 years than within 9 years (P<.05). Furthermore, 16.39% of total magnetic attachments showed detachment of keeper or assembly.

CONCLUSION

Attractive force of magnetic attachment is maintained regardless of conditional variables and reduction ratio increased as the maintenance period became longer. Further study on adhesive material, attachment method and design improvement to prevent detachment of magnetic attachment is needed.

Retinal vessel structure measurement using spectral-domain optical coherence tomography

PURPOSE

To assess the reliability and validity of spectral-domain optical coherence tomography (SD-OCT) measurements of retinal vessel lumen diameters and wall thicknesses.

METHODS

SD-OCT was used to characterize the circular region around the optic disc of 40 eyes (20 subjects). The inner and outer sides (vitreal and choroidal sides) of the vessel wall and the luminal diameter were measured using intensity graphs.

RESULTS

Mean arterial and venous luminal diameters were 95.1±16.1 and 132.6±17.8 μm, respectively. The wall thicknesses of inner and outer sides of the artery were 23.9±4.9 and 21.2±3.5 μm, respectively. The wall thicknesses of the inner and outer sides of the vein were 20.7±4.2 and 16.3±4.3 μm, respectively. There were significant differences between the inner and outer wall thicknesses in both the artery and vein (P<0.01). Intra- and interobserver intraclass correlation coefficients (ICCs) for lumen measurements were >0.95, and for wall thicknesses were >0.85, except for the outer wall thickness measurements. The mean value of outer and inner wall thicknesses showed good reproducibility, with ICCs of >0.85.

CONCLUSION

Intensity graph-assisted measurements using SD-OCT provided more objective information in finding boundaries of vessels. Luminal diameters and wall thicknesses obtained with OCT showed good overall reproducibility, with inner wall thicknesses being thicker, and with better reproducibility compared with outer wall thicknesses, where ICC values were the lowest among the inner wall thicknesses, mean thicknesses of inner and outer walls, and luminal diameters. When using SD-OCT measurements, caution is therefore advised when using only the outer wall as representative of the wall thicknesses.

Internal herniation due to an omphalomesenteric duct cyst in a 69-year-old man

Previous abdominal surgery is the most common cause of mechanical small bowel obstruction. However, in patients with no history of abdominal surgery, the diagnosis and treatment of mechanical small bowel obstruction is difficult. A persistent omphalomesenteric duct remnant is a rare finding that typically presents in the pediatric population and is extremely rare in patients aged > 60 years. In the present report, we describe the case of an omphalomesenteric duct cyst causing small bowel obstruction in a 69-year-old man with no history of a surgical procedure.

The Added Prognostic Value of Preoperative Dynamic Contrast-Enhanced MRI Histogram Analysis in Patients with Glioblastoma: Analysis of Overall and Progression-Free Survival

BACKGROUND AND PURPOSE

The prognostic value of dynamic contrast-enhanced MR imaging in patients with glioblastoma is controversial. We investigated the added prognostic value of dynamic contrast-enhanced MR imaging to clinical parameters and molecular biomarkers in patients with glioblastoma by using histogram analysis.

MATERIALS AND METHODS

This retrospective study consisted of 61 patients who underwent preoperative dynamic contrast-enhanced MR imaging for glioblastoma. The histogram parameters of dynamic contrast-enhanced MR imaging, including volume transfer constant, extravascular extracellular volume fraction, and plasma volume fraction, were calculated from entire enhancing tumors. Univariate analyses for overall survival and progression-free survival were performed with preoperative clinical and dynamic contrast-enhanced MR imaging parameters and postoperative molecular biomarkers. Multivariate Cox regression was performed to build pre- and postoperative models for overall survival and progression-free survival. The performance of models was assessed by calculating the Harrell concordance index.

RESULTS

In univariate analysis, patients with higher volume transfer constant and extravascular extracellular volume fraction values showed worse overall survival and progression-free survival, whereas plasma volume fraction showed no significant correlation. In multivariate analyses for overall survival, the fifth percentile value of volume transfer constant and kurtosis of extravascular extracellular volume fraction were independently prognostic in the preoperative model, and kurtosis of volume transfer constant and extravascular extracellular volume fraction were independently prognostic in the postoperative model. For progression-free survival, independent prognostic factors were minimum and fifth percentile values of volume transfer constant and kurtosis of extravascular extracellular volume fraction in the preoperative model and kurtosis of extravascular extracellular volume fraction in the postoperative model. The performance of preoperative models for progression-free survival was significantly improved when minimum or fifth percentile values of volume transfer constant and kurtosis of extravascular extracellular volume fraction were added.

CONCLUSIONS

Higher volume transfer constant and extravascular extracellular volume fraction values are associated with worse prognosis, and dynamic contrast-enhanced MR imaging may have added prognostic value in combination with preoperative clinical parameters, especially in predicting progression-free survival.

Discrimination of Tumorous Intracerebral Hemorrhage from Benign Causes Using CT Densitometry

BACKGROUND AND PURPOSE

Differentiation of tumorous intracerebral hemorrhage from benign etiology is critical in initial treatment plan and prognosis. Our aim was to investigate the diagnostic value of CT densitometry to discriminate tumorous and nontumorous causes of acute intracerebral hemorrhage.

MATERIALS AND METHODS

This retrospective study included 110 patients with acute intracerebral hemorrhage classified into 5 groups: primary intracerebral hemorrhage without (group 1) or with antithrombotics (group 2) and secondary intracerebral hemorrhage with vascular malformation (group 3), brain metastases (group 4), or primary brain tumors (group 5). The 5 groups were dichotomized into tumorous (groups 4 and 5) and nontumorous intracerebral hemorrhage (groups 1-3). Histogram parameters of hematoma attenuation on nonenhanced CT were compared among the groups and between tumorous and nontumorous intracerebral hemorrhages. With receiver operating characteristic analysis, optimal cutoffs and area under the curve were calculated for discriminating tumorous and nontumorous intracerebral hemorrhages.

RESULTS

Histogram analysis of acute intracerebral hemorrhage attenuation showed that group 1 had higher mean, 5th, 25th, 50th, and 75th percentile values than groups 4 and 5 and higher minimum and 5th percentile values than group 2. Group 3 had higher 5th percentile values than groups 4 and 5. After dichotomization, all histogram parameters except maximum and kurtosis were different between tumorous and nontumorous intracerebral hemorrhages, with tumors having lower cumulative histogram parameters and positive skewness. In receiver operating characteristic analysis, 5th and 25th percentile values showed the highest diagnostic performance for discriminating tumorous and nontumorous intracerebral hemorrhages, with 0.81 area under the curve, cutoffs of 34 HU and 44 HU, sensitivities of 65.6% and 70.0%, and specificities of 85.0% and 80.0%, respectively.

CONCLUSIONS

CT densitometry of intracerebral hemorrhage on nonenhanced CT might be useful for discriminating tumorous and nontumorous causes of acute intracerebral hemorrhage.

The predictors for continuous renal replacement therapy in liver transplant recipients

BACKGROUND

Acute renal failure (ARF) after liver transplantation requiring continuous renal replacement therapy (CRRT) adversely affects patient survival. We suggested that postoperative renal failure can be predicted if a clinically simple nomogram can be developed, thus selecting potential risk factors for preventive strategy.

METHODS

We retrospectively reviewed the medical records of 153 liver transplant recipients from January 2008 to December 2011 at Severance Hospital, Yonsei University Health System, in Seoul, Korea. There were 42 patients treated with CRRT (20 and 22 patients received transplants from living and deceased donors, respectively) and 115 were not. Univariate and stepwise logistic multivariate analyses were performed. A clinical nomogram to predict postoperative CRRT application was constructed and validated internally.

RESULTS

Hepatic encephalopathy (HEP; odds ratio OR, 5.47), deceased donor liver donations (OR, 3.47), Model for End-Stage Liver Disease (MELD) score (OR, 1.09), intraoperative blood loss (L; OR, 1.16), and tumor (hepatocellular carcinoma) as the indication for liver transplantation (OR, 0.11) were identified as independent predictive factors for postoperative CRRT on multivariate analysis. A clinical prediction model constructed for calculating the probability of CRRT post-transplantation was 1.7000 × HEP + [-4.5427 + 1.2440 × (deceased donor) + 0.0830 × (MELD score) + 0.000149 × the amount of intraoperative bleeding (L) - 2.1785 × tumor]. The validation set discriminated well with an area under the curve (AUC) of 0.90 (95% confidence interval, 0.85-0.95). The predicted and the actual probabilities were calibrated with the clinical nomogram.

CONCLUSIONS

We developed a predictive model of postoperative CRRT in liver transplantation patients. Perioperative strategies to modify these factors are needed.

Investigation of Werner protein as an early DNA damage response in actinic keratosis, Bowen disease and squamous cell carcinoma

BACKGROUND

Werner protein (WRN) has DNA helicase activity and participates in recombination, replication and repair of DNA. Loss-of-function mutations in WRN gives rise to genetic instability and diseases such as premature ageing and cancer. Upregulation of WRN promotes proliferation and survival of cancer cells.

AIM

To evaluate the expression pattern of WRN in closely related skin cancers and their correlation with age, sex and UV exposure.

METHODS

Immunohistochemistry was used to investigate expression of WRN in formalin-fixed, paraffin wax-embedded tissue specimens of 9 squamous cell carcinoma (SCC), 15 actinic keratosis (AK), 11 Bowen disease (BD) and 11 normal-appearing peripheral tissue samples, obtained from patients during surgical resections.

RESULTS

WRN expression was significantly increased in BD, AK and SCC compared with normal controls, with the mean WRN staining score being highest in BD, followed by AK and SCC. However, age, sex and sun exposure were not associated with WRN expression.

CONCLUSIONS

To our knowledge, this is the first report to date investigating the expression of WRN in skin cancers. The overtly high expression of WRN in premalignant lesions and in in situ cancer, with relatively low WRN expression in SCC, may indicate that WRN contributes as a checkpoint for early DNA damage response in skin tumorigenesis.

Association of metabolic syndrome with coronary atherosclerosis in non-diabetic postmenopausal women

OBJECTIVE

We investigated the possible association of metabolic syndrome with arterial stiffness and coronary atherosclerosis in non-diabetic, postmenopausal women.

METHODS

A total of 293 non-diabetic, postmenopausal women who visited the health promotion center for a routine health check-up were included in a cross-sectional study. Arterial stiffness was measured by brachial-ankle pulse wave velocity, and coronary atherosclerosis was detected using 64-row multi-detector computed tomography.

RESULTS

Women with coronary atherosclerosis had a significantly higher proportion of metabolic syndrome than those without coronary atherosclerosis. The brachial-ankle pulse wave velocity was significantly higher in women who had metabolic syndrome compared to those who had no metabolic syndrome (1567.71 ± 211.81 vs. 1336.75 ± 159.62 cm/s, p < 0.001). In addition, the brachial-ankle pulse wave velocity was shown to increase with increasing number of metabolic syndrome components (p for trend < 0.001). Metabolic syndrome was associated with increased risk of coronary atherosclerosis (adjusted odds ratio 2.38; 95% confidence interval 1.01-5.06), after adjusting for confounding factors.

CONCLUSIONS

Metabolic syndrome increases the risk of coronary atherosclerosis in postmenopausal women. Increased arterial stiffness may partly explain an increased risk of coronary atherosclerosis in postmenopausal women with metabolic syndrome.

Improved methods for selective cryolipolysis results in subcutaneous fat layer reduction in a porcine model

BACKGROUND/AIMS

Cryolipolysis is a noninvasive method for the selective reduction of localized fat tissues. It has demonstrated efficacy in both clinical and preclinical trials; however, despite its popularity, its mechanisms of action and evaluation methods are not yet fully defined. The purpose of this study was to improved methods for cryolipolysis using a porcine model.

METHODS

The abdomens of female PWG micro-pigs were treated with a cooling device (CRYOLIPO II(™)), and we examined the treatment effects using photography, three-dimensional photography, ultrasound, gross, and microscopic pathology, and serum lipid level analyses in order to determine the mechanism of action, efficacy, and safety of CRYOLIPO II(™).

RESULTS

CRYOLIPO II(™) successfully reduced abdominal fat in our porcine model. Gross and microscopic histological results confirmed the noninvasive cold-induced selective subcutaneous fat destruction, and showed increases in pre-adipocyte differentiation and in the activation of lipid catabolism. In particular, we found that CRYOLIPO II(™) may increase PPARδ (delta) levels in adipose tissue at 30-60 days post-treatment.

CONCLUSION

Fat reduction by cryolipolysis was successfully achieved in our porcine model. Thus, our findings indicate that CRYOLIPO II(™) may be a promising fat reduction device for body contouring and fat reduction in humans, and that cryolipolysis exerts its effects, at least partly, by targeting the PPARδ signaling pathway. These results show that both investigative and diagnostic potentials capacity.

Comparison of the effects of normal saline versus Plasmalyte on acid-base balance during living donor kidney transplantation using the Stewart and base excess methods

BACKGROUND

Ischemia-reperfusion injury is an inevitable consequence of kidney transplantation, leading to metabolic acidosis. This study compared the effects of normal saline (NS) and Plasmalyte on acid-base balance and electrolytes during living donor kidney transplantation using the Stewart and base excess (BE) methods.

METHODS

Patients were randomized to an NS group (n = 30) or a Plasmalyte group (n = 30). Arterial blood samples were collected for acid-base analysis after induction of anesthesia (T0), prior to clamping the iliac vein (T1), 10 minutes after reperfusion of the donated kidney (T2), and at the end of surgery (T3). In addition serum creatinine and 24-hour urine output were recorded on postoperative days 1,2, and 7. Over the first postoperative 7 days we recorded episodes of graft failure requiring dialysis.

RESULTS

Compared with the Plasmalyte group, the NS group showed significantly lower values of pH, BE, and effective strong ion differences during the postreperfusion period (T2 and T3). Chloride-related values (chloride [Cl(-)], free-water corrected Cl(-), BEcl) were significantly higher at T1, T2, and T3, indicating hyperchloremic rather than dilutional metabolic acidosis. Early postoperative graft functions in terms of serum creatinine, urine output, and graft failure requiring dialysis were not significantly different between the groups.

CONCLUSIONS

Both NS and Plamalyte can be used safely during uncomplicated living donor kidney transplantation. However, Plasmalyte more stably maintains acid-base and electrolyte balance compared with NS especially during the postreperfusion period.

Effects of soy sauce on physicochemical and textural properties of tumbled chicken breast

The objective of this study was to evaluate the effects of soy sauce on the physicochemical and textural properties of tumbled chicken breasts. Chicken breasts marinated with distilled water (Con), 4% NaCl solution, 4% NaCl and lactic acid solution (pH 4.9), and soy sauce solution (4% salt concentration and pH 4.9) were vacuum tumbled at 3°C for 60 min. The chicken breast marinated with soy sauce solution showed lower lightness and higher redness and yellowness due to the color of the soy sauce. The acidic marinades led to a decrease in pH value of tumbled chicken breast. The acidic marinades increased collagen solubility of sample compared with 4% NaCl solution, resulting in decreased shear force. Water-holding capacity, marination and cooking yields, and solubility of myofibrillar proteins were mainly affected by the presence of salt in the marinade, rather than by pH alternation. Our results suggested that soy sauce marination can improve the tenderness of tumbled chicken breast.

Relationship between socioeconomic status and anemia prevalence in adolescent girls based on the fourth and fifth Korea National Health and Nutrition Examination Surveys

BACKGROUND/OBJECTIVES

We studied the relationship between socioeconomic status (SES), represented by household income, and the prevalence of anemia and iron deficiency anemia (IDA) among adolescent girls in Korea.

SUBJECTS/METHODS

The samples were based on the data from a four-year (2008-2011) collection for the Korea National Health and Nutrition Examination Survey (1312 girls, age 10-18 years). The survey included demographic, anthropometric, biochemical and nutritional parameters. A multiple regression analysis after adjusting for age, body mass index (BMI), red blood cell count, white blood cell count and red meat intake was performed. Anemia was defined as hemoglobin level lower than 11.5 g/dl for ages 10-11 years and 12.0 g/dl for ages 12-14 years. Iron deficiency was defined as serum ferritin level below 15 μg/l.

RESULTS

The prevalences of anemia and IDA in Korean girls were 5.3 and 4.2%, respectively. Girls with anemia were older, taller, weighed more, had higher BMI, had higher portion of menarche experience and consumed less red meat than girls without anemia. Girls with higher income had lower anemia prevalence and consumed more iron and vitamins. Logistic regression analysis showed a decreasing trend in anemia prevalence as household income increased. Correlation analysis demonstrated that there is a relationship between household income and serum hemoglobin and ferritin levels (P=0.003 and P=0.026, respectively).

CONCLUSIONS

Higher SES leads to lower prevalence of anemia and IDA in Korean adolescent girls. This may be due to the fact that higher SES individuals consume more iron and vitamin C.

Randomized controlled comparison of combined general and epidural anesthesia versus general anesthesia on diaphragmatic function after laparoscopic prostatectomy

BACKGROUND

Little is known about the effect of anesthetic technique on postoperative diaphragmatic function, which is associated with postoperative morbidity and recovery in patients undergoing laparoscopic pelvic surgery. The aim of this trial was to study the effect of combined general and epidural anesthesia versus general anesthesia on postoperative diaphragmatic function measured by ultrasonography in patients undergoing robot-assisted laparoscopic radical prostatectomy (RALRP).

METHODS

Fifty-four patients undergoing RALRP were enrolled prospectively. Study population was randomized to receive general (group G, N.=27) or combined general and epidural (group GE, N.=27) anesthesia. Diaphragmatic inspiratory amplitude (DIA), and inspiration and expiration time (Ti and Te, respectively) were measured by M-mode ultrasonography during quiet/deep breathing and sniffing before the surgery and on postoperative days (POD) 1 and 2. Diaphragmatic inspiratory and expiratory velocities (DIV and DEV) were also calculated (DIA/Ti and DIA/Te, respectively). Spirometry was performed in addition to ultrasonography.

RESULTS

DIA during deep breathing and sniffing was significantly decreased on POD 1 in group G, while it was preserved in group GE. These reductions in diaphragmatic function were restored to preoperative values on POD 2 in both groups. Vital capacity and peak expiratory flow were diminished in group G on POD 1 and 2. However, spirometry revealed no impairment in group GE except for vital capacity on POD 1. The correlation coefficients (R2) between diaphragmatic function and spirometry variables ranged from 0.231 to 0.286. Postoperaitve pain was comparable.

CONCLUSION

Combined general and epidural anesthesia may attenuate the severity of postoperative diaphragmatic dysfunction after RALRP compared to conventional general anesthesia.

Effects of single-dose dexmedetomidine on the quality of recovery after modified radical mastectomy: a randomised controlled trial

BACKGROUND

Dexmedetomidine is a highly selective α2 agonist with analgesic, anxiolytic, and anti-inflammatory properties. We investigated the effect of a single dose of dexmedetomidine on patient-perceived quality of recovery and clinical recovery variables after modified radical mastectomy under general anesthesia in this randomized, double-blind, placebo-controlled study.

METHODS

After Institutional Review Board approval, ninety two female patients were randomly allocated to receive intravenously either saline (Group C, N.=46) or 0.5 μg/kg of dexmedetomidine (Group D, N.=46) five min before the end of surgery. The quality of recovery was assessed using a 40-item quality-of-recovery scoring system (QoR-40) preoperatively and 24 h after surgery. Pain intensity, rescue analgesics, and postoperative nausea and vomiting (PONV) were assessed at postanesthesia care unit (PACU), 1-6 h, and 6-24 h after surgery.

RESULTS

Postoperative global QoR-40 scores were higher in Group D compared with Group C (181 [175-187] vs. 174 [154.5-181.5], P=0.004); postoperative QoR-40 scores were improved in the dimensions of emotional state, physical comfort, and psychological support. Total amount of tramadol during 24 h after surgery was significantly lower in Group D than in Group C (54 vs. 76 mg, P=0.006). The incidence of PONV was lower in Group D than in Group C in PACU (21% vs. 43%, P=0.026) and 6-24 h period after surgery (10% vs. 41%, P=0.012). Heart rate and mean blood pressure were significantly lower in Group D as compared with Group C at 5 min after administration of dexmedetomidine, 1 min after extubation, and 20 min after arrival in PACU.

CONCLUSION

The use of a single dose dexmedetomidine improved the quality of recovery and reduced analgesic requirements and the incidence of PONV in the early postoperative period after modified radical mastectomy.

Evaluation of acid-base status in brain dead donors and the impact of metabolic acidosis on organ retrieval

BACKGROUND

Pathophysiologic changes after brain death can lead to acid-base disturbances. The primary aim of this study was to clarify the acid-base state and its source in brain dead donors using Stewart's approach. Additionally, we investigated whether the presence of metabolic acidosis affected the number of organs retrieved from donors.

METHODS

A retrospective review of electronic medical records was performed for brain dead donors who had undergone organ harvesting during the past 5 years in a tertiary medical center. The parameters related to acid-base disturbance and the number of organs retrieved from the donors was assessed.

RESULTS

Sixty one brain dead donors were evaluated in this study. Twenty three (37.7%) of these patients had metabolic acidosis at the initial diagnosis of brain death. Metabolic acidosis resulted from hyperchloremia and a large strong ion gap. The severity of metabolic acidosis was masked by hypernatremia and hypoalbuminemia. In addition, donors without metabolic acidosis also showed mixed acid-base disturbances in which metabolic acidosis induced by significant hyperchloremia was combined with metabolic alkalosis caused by hypoalbuminemia and hypernatremia. Although more organs were retrieved from the donors without metabolic acidosis than those with metabolic acidosis (P=0.012), serum albumin level (P=0.010) and donor age (P<0.001), rather than metabolic acid-base disturbances, significantly correlated with the number of organs retrieved in multivariate regression analysis.

CONCLUSION

Most brain dead donors exhibited metabolic acid-base disturbances. However, rather than metabolic acidosis, serum albumin level and donor age were well correlated with the number of organs retrieved.