Orphan nuclear receptor ERR-γ regulates hepatic FGF23 production in acute kidney injury.

Fibroblast growth factor 23 (FGF23), a hormone generally derived from bone, is important in phosphate and vitamin D homeostasis. In acute kidney injury (AKI) patients, high-circulating FGF23 levels are associated with disease progression and mortality. However, the organ and cell type of FGF23 production in AKI and the molecular mechanism of its excessive production are still unidentified. For insight, we investigated folic acid (FA)-induced AKI in mice. Interestingly, simultaneous with FGF23, orphan nuclear receptor ERR-γ expression is increased in the liver of FA-treated mice, and ectopic overexpression of ERR-γ was sufficient to induce hepatic FGF23 production. In patients and in mice, AKI is accompanied by up-regulated systemic IL-6, which was previously identified as an upstream regulator of ERR-γ expression in the liver. Administration of IL-6 neutralizing antibody to FA-treated mice or of recombinant IL-6 to healthy mice confirms IL-6 as an upstream regulator of hepatic ERR-γ-mediated FGF23 production. A significant (P < 0.001) interconnection between high IL-6 and FGF23 levels as a predictor of AKI in patients that underwent cardiac surgery was also found, suggesting the clinical relevance of the finding. Finally, liver-specific depletion of ERR-γ or treatment with an inverse ERR-γ agonist decreased hepatic FGF23 expression and plasma FGF23 levels in mice with FA-induced AKI. Thus, inverse agonist of ERR-γ may represent a therapeutic strategy to reduce adverse plasma FGF23 levels in AKI.

Inhibition of pyruvate dehydrogenase kinase 4 ameliorates kidney ischemia-reperfusion injury by reducing succinate accumulation during ischemia and preserving mitochondrial function during reperfusion.

Ischemia-reperfusion (IR) injury, a leading cause of acute kidney injury (AKI), is still without effective therapies. Succinate accumulation during ischemia followed by its oxidation during reperfusion leads to excessive reactive oxygen species (ROS) and severe kidney damage. Consequently, the targeting of succinate accumulation may represent a rational approach to the prevention of IR-induced kidney injury. Since ROS are generated primarily in mitochondria, which are abundant in the proximal tubule of the kidney, we explored the role of pyruvate dehydrogenase kinase 4 (PDK4), a mitochondrial enzyme, in IR-induced kidney injury using proximal tubule cell-specific Pdk4 knockout (Pdk4ptKO) mice. Knockout or pharmacological inhibition of PDK4 ameliorated IR-induced kidney damage. Succinate accumulation during ischemia, which is responsible for mitochondrial ROS production during reperfusion, was reduced by PDK4 inhibition. PDK4 deficiency established conditions prior to ischemia resulting in less succinate accumulation, possibly because of a reduction in electron flow reversal in complex II, which provides electrons for the reduction of fumarate to succinate by succinate dehydrogenase during ischemia. The administration of dimethyl succinate, a cell-permeable form of succinate, attenuated the beneficial effects of PDK4 deficiency, suggesting that the kidney-protective effect is succinate-dependent. Finally, genetic or pharmacological inhibition of PDK4 prevented IR-induced mitochondrial damage in mice and normalized mitochondrial function in an in vitro model of IR injury. Thus, inhibition of PDK4 represents a novel means of preventing IR-induced kidney injury, and involves the inhibition of ROS-induced kidney toxicity through reduction in succinate accumulation and mitochondrial dysfunction.

Intimal flap detected by three-dimensional curved multiplanar reconstruction image in isolated posterior inferior cerebellar artery dissection: a report of two cases.

BACKGROUND: Spontaneous isolated posterior inferior cerebellar artery (PICA) dissection has been reported more frequently since high-resolution vessel wall magnetic resonance imaging (HR vw-MRI) was introduced to the field. The intimal flap or double lumen, which is commonly reported to be a direct sign of the dissection, is not easily detectable on HR vw-MRI because the size of the PICA is very small and tortuous. CASE PRESENTATION: Two patients with posterior circulation ischemic stroke due to spontaneous isolated PICA dissection underwent HR vw-MRI. The curved multiplanar reconstruction image reconstructed using three-dimensional (3D) HR vw-MRI (3D curved MPR imaging) is helpful to observe tortuous blood vessels such as the PICA because it can visualize the entire vessel course in a single plane. In this report, routine HR vw-MRI revealed only an intramural hematoma in both patients. However, 3D curved MPR imaging discovered the intimal flap which was not observed on the routine HR vw-MRI. Therefore, these two patients were diagnosed with spontaneous isolated PICA dissection due to the intimal flap that was observed on the 3D curved MPR image. CONCLUSION: HR vw-MRI is useful for the early diagnosis of isolated PICA dissection. Furthermore, we believe that 3D curved MPR imaging could improve the possibility of diagnosing the dissection early because it can easily confirm direct signs such as an intimal flap or double lumen.

Integration of sputter-deposited multiferroic CoFe2O4-BiFeO3 nanocomposites on conductive La0.7Sr0.3MnO3 electrodes.

The structure, magnetic and ferroelectric properties of sputtered epitaxial CoFe2O4-BiFeO3 (CFO-BFO) nanocomposite thin films grown on La0.7Sr0.3MnO3 (LSMO) layers on (001) oriented SrTiO3 (STO) substrates and on STO-buffered Si are described. The as-grown LSMO thin films were smooth and poorly conductive but the resistivity was reduced and the surfaces roughened after annealing. Cosputtered CFO and BFO on STO formed vertically aligned nanostructures consisting of epitaxial spinel CFO pillars within a perovskite BFO matrix, but the rough surface of the annealed LSMO film promoted additional CFO pillar orientations. A reorientation of the CFO magnetic easy axis to an in-plane direction occurred as the LSMO became thicker due to changes in the strain state of the CFO pillars. The LSMO underlayer enabled the ferroelectric response of the BFO to be measured. Nanocomposites were grown onto LSMO/SrTiO3/Si which provides a path towards large scale integration of electrically contacted nanocomposites on Si.

A comparison of the Health Star Rating and nutrient profiles of branded and generic food products in Sydney supermarkets, Australia.

OBJECTIVE: To compare the Health Star Rating (HSR) and the nutritional profile of branded and generic packaged foods in Australia. DESIGN: In-store audits of packaged food products capturing data on HSR and nutritional content to analyse differences between branded and generic foods across ten food categories. SETTING: The audit was conducted in four major supermarket chains across various locations within metropolitan Sydney regions, Australia. RESULTS: A total of 6269 products were analysed with 57 % of generic products and 28 % of branded products displaying an HSR. The median HSR of branded products was significantly greater than for generic products overall (4·0 v. 3·5, P<0·005) and in six out of ten food categories (P<0·005). However, when branded products could be matched to their generic counterparts for paired comparisons (n 146), no statistical difference was observed in all ten food categories. Branded products that chose to display an HSR had significantly lower saturated fat and Na, but higher fibre contents than branded products not displaying an HSR. CONCLUSIONS: Our data show no difference in the HSR or nutrient profiles of similar branded and generic products that display HSR. Branded products appear to exploit the voluntary nature of the HSR scheme, preferentially displaying an HSR on healthier products compared with their generic counterparts.

Synthesis of gold structures by gold-binding peptide governed by concentration of gold ion and peptide.

Although biological synthesis methods for the production of gold structures by microorganisms, plant extracts, proteins, and peptide have recently been introduced, there have been few reports pertaining to controlling their size and morphology. The gold ion and peptide concentrations affected on the size and uniformity of gold plates by a gold-binding peptide Midas-11. The higher concentration of gold ions produced a larger size of gold structures reached 125.5 µm, but an increased amount of Midas-11 produced a smaller size of gold platelets and increased the yield percentage of polygonal gold particles rather than platelets. The mechanisms governing factors controlling the production of gold structures were primarily related to nucleation and growth. These results indicate that the synthesis of gold architectures can be controlled by newly isolated and substituted peptides under different reaction conditions.

Length Scale of the Spin Seebeck Effect.

We investigate the origin of the spin Seebeck effect in yttrium iron garnet (YIG) samples for film thicknesses from 20 nm to 50 µm at room temperature and 50 K. Our results reveal a characteristic increase of the longitudinal spin Seebeck effect amplitude with the thickness of the insulating ferrimagnetic YIG, which levels off at a critical thickness that increases with decreasing temperature. The observed behavior cannot be explained as an interface effect or by variations of the material parameters. Comparison to numerical simulations of thermal magnonic spin currents yields qualitative agreement for the thickness dependence resulting from the finite magnon propagation length. This allows us to trace the origin of the observed signals to genuine bulk magnonic spin currents due to the spin Seebeck effect ruling out an interface origin and allowing us to gauge the reach of thermally excited magnons in this system for different temperatures. At low temperature, even quantitative agreement with the simulations is found.

SrGa(0.7)Co(0.3)O(3-δ) perovskite-cobalt oxide-metal nanocomposite films: magnetic and optical properties.

Two-phase nanocomposite films consisting of metallic Co nanoparticles below 50 nm diameter in a perovskite matrix were grown by pulsed laser deposition onto (LaAlO3)0.3(Sr2AlTaO6)0.7 (LSAT) and silicon substrates from a target of SrGa0.73Co0.27O3. The particles made up about 6% by volume of the film and were present within the film and at the substrate interface. The saturation magnetization of the film was up to 85 emu cm(-3) at 80 nm thickness and the Faraday rotation (FR) tracked the out-of-plane hysteresis loop, reaching 3000 deg cm(-1) at 10 kOe for 1550 nm wavelength. The magneto-optical figure of merit defined as FR divided by optical absorption was 0.04-0.06 deg dB(-1) due to the high optical absorption of the Co particles.

A nonreciprocal racetrack resonator based on vacuum-annealed magnetooptical cerium-substituted yttrium iron garnet.

Vacuum annealed polycrystalline cerium substituted yttrium iron garnet (CeYIG) films deposited by radio frequency magnetron sputtering on non-garnet substrates were used in nonreciprocal racetrack resonators. CeYIG annealed at 800°C for 30 min provided a large Faraday rotation angle, close to the single crystal value. Crystallinity, magnetic properties, refractive indices and absorption coefficients were measured. The resonant transmission peak of the racetrack resonator covered with CeYIG was non-reciprocally shifted by applying an in-plane magnetic field.

Intraductal papillary neoplasms and mucinous cystic neoplasms of the hepatobiliary system: demographic differences between Asian and Western populations, and comparison with pancreatic counterparts.

AIMS: To improve the characterization of intraductal papillary neoplasm of the bile duct (IPNB) and mucinous cystic neoplasm of the liver (MCN-L). METHODS AND RESULTS: A retrospective review of pathology archives (1999-2011) in our three institutions identified cases of IPNB (n = 138) and MCN-L (n = 54). The IPNB/MCN-L ratio was 5.7:1 at Samsung Medical Centre in Seoul, which was significantly higher than those at the University of Washington Medical Center in Seattle (1:3.0) and King's College Hospital in London (1:6.3). This difference was mainly attributable to the considerably larger number of patients with IPNB in Seoul (n = 131) than in Seattle and London (n = 7). Western patients with IPNB were all non-Asian in ancestry. IPNB differed from pancreatic intraductal papillary neoplasm in its higher histological grade, more advanced stage of an associated invasive cancer, and worse prognosis. In contrast, MCN-L showed significantly lower histological grade than its pancreatic counterpart (P = 0.022). Unlike in pancreatic mucinous cystic neoplasm, malignant transformation was very rare in MCN-L (10% versus 2%). CONCLUSIONS: This study demonstrated demographic differences in IPNB and MCN-L among regions. IPNB and MCN-L differ from their pancreatic counterparts in the risk of malignant transformation and patients' prognosis.

Accumulation of amorphous Cr(III)-Te(IV) nanoparticles on the surface of Shewanella oneidensis MR-1 through reduction of Cr(VI).

Industrial effluents constitute a major source of metal pollution of aquatic bodies. Moreover, due to their environmental persistence, toxic metal pollution is of special concern. Microbial reduction is considered a promising strategy for toxic metal removal among the several methods available for metal remediation. Here, we describe the coremediation of toxic Cr(VI) and Te(IV) by the dissimilatory metal reducing bacterium-Shewanella oneidensis MR-1. In the presence of both Cr(VI) and Te(IV), S. oneidensis MR-1 reduced Cr(VI) to the less toxic Cr(III) form, but not Te(IV) to Te(0). The reduced Cr(III) ions complexed rapidly with Te(IV) ions and were precipitated from the cell cultures. Electron microscopic analyses revealed that the Cr-Te complexed nanoparticles localized on the bacterial outer membranes. K-edge X-ray absorption spectrometric analyses demonstrated that Cr(III) produced by S. oneidensis MR-1 was rapidly complexed with Te(IV) ions, followed by formation of amorphous Cr(III)-Te(IV) nanoparticles on the cell surface. Our results could be applied for the simultaneous sequestration and detoxification of both Cr(VI) and Te(IV) as well as for the preparation of nanomaterials through environmental friendly processes.

Genetic diversity and relationships of korean chicken breeds based on 30 microsatellite markers.

The effective management of endangered animal genetic resources is one of the most important concerns of modern breeding. Evaluation of genetic diversity and relationship of local breeds is an important factor towards the identification of unique and valuable genetic resources. This study aimed to analyze the genetic diversity and population structure of six Korean native chicken breeds (n = 300), which were compared with three imported breeds in Korea (n = 150). For the analysis of genetic diversity, 30 microsatellite markers from FAO/ISAG recommended diversity panel or previously reported microsatellite markers were used. The number of alleles ranged from 2 to 15 per locus, with a mean of 8.13. The average observed heterozygosity within native breeds varied between 0.46 and 0.59. The overall heterozygote deficiency (F IT) in native chicken was 0.234±0.025. Over 30.7% of F IT was contributed by within-population deficiency (F IS). Bayesian clustering analysis, using the STRUCTURE software suggested 9 clusters. This study may provide the background for future studies to identify the genetic uniqueness of the Korean native chicken breeds.

Hemostatic effect of fibrinogen concentrate on traumatic massive hemorrhage: a propensity score matching study.

Background: Fibrinogen concentrate (FC) can be administered during massive transfusions to manage trauma-induced coagulopathy. However, its effectiveness in survival remains inconclusive due to scarce high-level evidence. This study aimed to investigate the hemostatic effects of FC regarding mortality in massive hemorrhage caused by trauma. Methods: This retrospective study analyzed 839 patients who received massive transfusions (red blood cells (RBCs) ≥5 units in 4 hours or ≥10 units in 24 hours) at a level I trauma center between 2015 and 2022. Patients who were transferred to other hospitals or were deceased upon arrival, suffered or died from severe brain injury, and were aged 15 years or less were excluded (n=334). 1:2 propensity score matching was performed to compare the 'FC (+)' group who had received FC in 24 hours (n=68) with those who had not ('FC (-)', n=437). The primary outcome was mortality, and the secondary outcomes included transfusion volume. Results: The variables for matching included vital signs, injury characteristics, prehospital time, implementation of resuscitative endovascular balloon occlusion of the aorta, and blood gas analysis results. The administration of FC did not significantly reduce or predict mortality (in-hospital, 24 hours, 48 hours, or 7 days). The FC (-) group received more units of RBC (25.69 units vs. 16.71 units, p<0.001, standardized mean difference [SMD] 0.595), fresh frozen plasma (16.79 units vs. 12.91 units, p=0.023, SMD 0.321), and platelets (8.76 units vs. 5.46 units, p=0.002, SMD 0.446) than the FC (+) group. Conclusion: The use of FC did not show survival benefits but reduced transfusion requirements in traumatic massive hemorrhages, highlighting a need for future investigations. In the future, individualized goal-directed transfusion with FC may play a significant role in treating massive bleeding. Level of evidence: IV, retrospective study having more than one negative criterion.

Clinical and Radiological Outcomes in C2 Recapping Laminoplasty for the Pathologies in the Upper Cervical Spine.

OBJECTIVE: To evaluate C2 muscle preservation effect and the radiological and clinical outcomes after C2 recapping laminoplasty. METHODS: Fourteen consecutive patients who underwent C2 recapping laminoplasty around C1-2 level were enrolled. To evaluate muscle preservation effect, the authors conducted a morphological measurement of extensor muscles between the operated and nonoperated side. Two surgeons measured the cross-sectional area (CSA) of obliquus capitis inferior (OCI) and semispinalis cervicis (SSC) muscle before and after surgery to determine atrophy rates (ARs). Additionally, we examined range of motion (ROM), sagittal vertical axis (SVA), neck visual analogue scale (VAS), Neck Disability Index (NDI), and Japanese Orthopaedic Association (JOA) score to assess potential changes in alignment and consequent clinical outcomes following posterior cervical surgery. RESULTS: We measured the CSA of OCI and SSC before surgery, and at 6 and 12 months postoperatively. Based on these measurements, the AR of the nonoperated SSC was 0.1% ± 8.5%, the AR of the operated OCI was 2.0% ± 7.2%, and the AR of the nonoperated OCI was -0.7% ± 5.1% at the 12 months after surgery. However, the AR of the operated side's SSC was 11.2% ± 12.5%, which is a relatively higher value than other measurements. Despite the atrophic change of SSC on the operated side, there were no prominent changes observed in SVA, C0-2 ROM, and C2-7 ROM between preoperative and 12 months postoperative measurements, which were 11.8 ± 10.9 mm, 16.3° ± 5.9°, and 48.7° ± 7.7° preoperatively, and 14.1 ± 11.6 mm, 16.1° ± 7.2°, and 44.0° ± 10.3° at 12 months postoperative, respectively. Improvement was also noted in VAS, NDI, and JOA scores after surgery with JOA recovery rate of 77.3% ± 29.6%. CONCLUSION: C2 recapping laminoplasty could be a useful tool for addressing pathologies around the upper cervical spine, potentially mitigating muscle atrophy and reducing postoperative neck pain, while maintaining sagittal alignment and ROM.

Reducing Oxidative Stress and Inflammation by Pyruvate Dehydrogenase Kinase 4 Inhibition Is Important in Prevention of Renal Ischemia-Reperfusion Injury in Diabetic Mice.

BACKGRUOUND: Reactive oxygen species (ROS) and inflammation are reported to have a fundamental role in the pathogenesis of ischemia-reperfusion (IR) injury, a leading cause of acute kidney injury. The present study investigated the role of pyruvate dehydrogenase kinase 4 (PDK4) in ROS production and inflammation following IR injury. METHODS: We used a streptozotocin-induced diabetic C57BL6/J mouse model, which was subjected to IR by clamping both renal pedicles. Cellular apoptosis and inflammatory markers were evaluated in NRK-52E cells and mouse primary tubular cells after hypoxia and reoxygenation using a hypoxia work station. RESULTS: Following IR injury in diabetic mice, the expression of PDK4, rather than the other PDK isoforms, was induced with a marked increase in pyruvate dehydrogenase E1α (PDHE1α) phosphorylation. This was accompanied by a pronounced ROS activation, as well as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1ß (IL-1ß), and monocyte chemoattractant protein-1 (MCP-1) production. Notably, sodium dichloroacetate (DCA) attenuated renal IR injury-induced apoptosis which can be attributed to reducing PDK4 expression and PDHE1α phosphorylation levels. DCA or shPdk4 treatment reduced oxidative stress and decreased TNF-α, IL-6, IL-1ß, and MCP-1 production after IR or hypoxia-reoxygenation injury. CONCLUSION: PDK4 inhibition alleviated renal injury with decreased ROS production and inflammation, supporting a critical role for PDK4 in IR mediated damage. This result indicates another potential target for reno-protection during IR injury; accordingly, the role of PDK4 inhibition needs to be comprehensively elucidated in terms of mitochondrial function during renal IR injury.

Nomogram for predicting in-hospital mortality in trauma patients undergoing resuscitative endovascular balloon occlusion of the aorta: a retrospective multicenter study.

Recently, resuscitative endovascular balloon occlusion of the aorta (REBOA) had been introduced as an innovative procedure for severe hemorrhage in the abdomen or pelvis. We aimed to investigate risk factors associated with mortality after REBOA and construct a model for predicting mortality. This multicenter retrospective study collected data from 251 patients admitted at five regional trauma centers across South Korea from 2015 to 2022. The indications for REBOA included patients experiencing hypovolemic shock due to hemorrhage in the abdomen, pelvis, or lower extremities, and those who were non-responders (systolic blood pressure (SBP) < 90 mmHg) to initial fluid treatment. The primary and secondary outcomes were mortality due to exsanguination and overall mortality, respectively. After feature selection using the least absolute shrinkage and selection operator (LASSO) logistic regression model to minimize overfitting, a multivariate logistic regression (MLR) model and nomogram were constructed. In the MLR model using risk factors selected in the LASSO, five risk factors, including initial heart rate (adjusted odds ratio [aOR], 0.99; 95% confidence interval [CI], 0.98-1.00; p = 0.030), initial Glasgow coma scale (aOR, 0.86; 95% CI 0.80-0.93; p < 0.001), RBC transfusion within 4 h (unit, aOR, 1.12; 95% CI 1.07-1.17; p < 0.001), balloon occlusion type (reference: partial occlusion; total occlusion, aOR, 2.53; 95% CI 1.27-5.02; p = 0.008; partial + total occlusion, aOR, 2.04; 95% CI 0.71-5.86; p = 0.187), and post-REBOA systolic blood pressure (SBP) (aOR, 0.98; 95% CI 0.97-0.99; p < 0.001) were significantly associated with mortality due to exsanguination. The prediction model showed an area under curve, sensitivity, and specificity of 0.855, 73.2%, and 83.6%, respectively. Decision curve analysis showed that the predictive model had increased net benefits across a wide range of threshold probabilities. This study developed a novel intuitive nomogram for predicting mortality in patients undergoing REBOA. Our proposed model exhibited excellent performance and revealed that total occlusion was associated with poor outcomes, with post-REBOA SBP potentially being an effective surrogate measure.

Promoted reduction of tellurite and formation of extracellular tellurium nanorods by concerted reaction between iron and Shewanella oneidensis MR-1.

The reduction of tellurite (Te(IV)) by dissimilatory metal reducing bacterium, Shewanella oneidensis MR-1, was promoted in the presence of Fe(III) in comparison with Te(IV) bioreduction in the absence of Fe(III). Electron microscopic analyses revealed that iron promoted Te(IV) reduction led to form exclusively extracellular crystalline Te(0) nanorods, as compared to the mostly intracellular formation of Te(0) nanorods in the absence of Fe(III). The Te K-edge X-ray absorption spectrometric analyses demonstrated that S. oneidensis MR-1 in the presence of Fe(III) reduced Te(IV) to less harmful metallic Te(0) nanorods through the precipitation of tellurite (Te(IV)Ox) complex by the bacterial respiration of Fe(III) to Fe(II) under anaerobic conditions. However, Fe(II) ion itself was only able to precipitate the solid tellurite (Te(IV)Ox) complex from the Te(IV) solution, which was not further reduced to Te(0). The results clearly indicated that bacterial S. oneidensis MR-1 plays important roles in the reduction and crystallization of Te(0) nanorods by as yet undetermined biochemical mechanisms. As compared to the slow bacterial Te(IV) reduction in the absence of Fe(III), the rapid reduction of Te(IV) to Te(0) by the concerted biogeochemical reaction between Fe(II) and S. oneidensis MR-1 could be applied for the sequestration and detoxification of Te(IV) in the environments as well as for the preparation of extracellular Te(0) nanorod structures.

The temporary abdominal closure techniques used for trauma patients: a systematic review and meta-analysis.

Purpose: The choice of temporary abdominal closure (TAC) method affects the prognosis of trauma patients. Previous studies on TAC are challenging to extrapolate due to data heterogeneity. We aimed to conduct a systematic review and comparison of various TAC techniques. Methods: We accessed web-based databases for studies on the clinical outcomes of TAC techniques. Recognized techniques, including negative-pressure wound therapy with or without continuous fascial traction, skin tension, meshes, Bogota bags, and Wittman patches, were classified via a method of closure such as skin-only closure vs. patch closure vs. vacuum closure; and via dynamics of treatment like static therapy (ST) vs. dynamic therapy (DT). Study endpoints included in-hospital mortality, definitive fascial closure (DFC) rate, and incidence of intraabdominal complications. Results: Among 1,065 identified studies, 37 papers comprising 2,582 trauma patients met the inclusion criteria. The vacuum closure group showed the lowest mortality (13%; 95% confidence interval [CI], 6%-19%) and a moderate DFC rate (74%; 95% CI, 67%-82%). The skin-only closure group showed the highest mortality (35%; 95% CI, 7%-63%) and the highest DFC rate (96%; 95% CI, 93%-99%). In the second group analysis, DT showed better outcomes than ST for all endpoints. Conclusion: Vacuum closure was favorable in terms of in-hospital mortality, ventral hernia, and peritoneal abscess. Skin-only closure might be an alternative TAC method in carefully selected groups. DT may provide the best results; however, further studies are needed.

CPR quality with rotation of every 1 versus 2 minutes as characteristics of rescuers: A randomized crossover simulation study.

BACKGROUND: Fatigue and rotation time are key factors affecting the quality of cardiopulmonary resuscitation (CPR). This study aimed to investigate the effects of rotation time on CPR duration, and sex on chest compression quality. METHODS: In this randomized crossover simulation study, we enrolled 100 paramedic students stratified by sex and randomly grouped into 28 male and 22 female pairs. In the 2- and 1-minute scenarios, 2 participants performed CPR for 20 minutes with a rotation cycle of 2 minutes and 1 minute, respectively. After taking a break, they changed over and performed CPR again for 20 minutes. The switching of roles was performed with the students positioned on opposite sides of the mannequin. For chest compression quality, a set was defined as CPR performed by 1 pair in a 2-minute scenario for 4 minutes. The quality of CPR in each set was compared between the 2 groups. RESULTS: The 1-minute group showed significantly higher chest compression depth than the 2-minute group (54.0 [51.5-57.0] vs 52.5 [48.5-56.5] mm, P = .001, respectively). The female 2-minute group showed decreased chest compression depth over time, and the 1-minute group showed significantly increased chest compression depth during all sets except the 2nd set (54.0 [51.9-55.1] vs 50.5 [48.5-53.8] mm [P = .030], 52.3 [49.4-54.5] vs 50.8 [47.0-53.1] mm [P = .080], 52.8 [49.8-54.5] vs 48.8 [45.4-51.6] mm [P = .002], 51.5 [48.5-53.3] vs 48.3 [44.5-50.6] mm [P = .004], and 50.8 [48.9-54.1] vs 47.5 [44.6-50.1] mm [P = .001], respectively). The fatigue scores in the 2-minute group were significantly higher during sets 4 and 5 than those in the 1-minute group. CONCLUSION: When rescuer fatigue increases during prolonged CPR owing to their physical strength and skill levels, the rotation of rescuers every minute would be helpful in maintaining high-quality CPR.