Facile Surface Modification of MgMn2O4 Positive-Electrode Material for Improving Cycle Performance of Magnesium Rechargeable Batteries.

MgMn2O4 with a tetragonal spinel structure shows promise as a positive-electrode material in magnesium rechargeable batteries (MRBs), which have drawn considerable attention as post lithium-ion batteries. However, the material currently suffers from poor cycle performance. In this study, we attempt to improve the cycle performance of MgMn2O4 via the Zr modification of its particle surface. X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy demonstrate that the surface modification is successfully performed by immersing MgMn2O4 powder into a Zr-containing aqueous solution, followed by heat treatment. However, Zr segregation is observed at high Zr concentration. Furthermore, structural analyses using synchrotron X-rays indicate that the Zr modification has an influence on the bulk structure of the MgMn2O4 powder. The positive-electrode properties of the powders are investigated using discharge/charge cycle tests, which show that Zr modification can drastically improve the cycle performance and coulombic efficiency. These improvements are supposed to be due to suppression of an unexpected reaction by the Zr-surface modification and lower structural distortion after the modification. These findings clearly demonstrate the significant potential of surface modification as a method for obtaining high-performance MRBs.

Positive-electrode properties and crystal structures of Mg-rich transition metal oxides for magnesium rechargeable batteries.

In this work, we focus on Mg-Fe-O and Mg-Ni-O with Mg-rich compositions as positive-electrode materials for magnesium rechargeable batteries, and prepare them by a thermal decomposition of precipitates obtained by a solution method. It is indicated from X-ray diffraction patterns that the Mg-Fe-O and Mg-Ni-O samples have the spinel and rocksalt structures, respectively. X-ray absorption near edge structures indicate that Fe and Ni are trivalent and divalent, respectively, in the Mg-rich oxides. From charge/discharge cycle test, it is demonstrated that the Mg-Fe-O shows higher discharge capacity than the other and then has good cycle performance while keeping a discharge capacity over 100 mA h g-1. To gain deeper understanding on a relationship between the electrode properties and the crystal structure of the Mg-Fe-O, the crystal structure is investigated by a Rietveld refinement using a synchrotron X-ray diffraction profile and an analysis on total correlation functions. It is indicated from these studies that a vacant octahedral site in the spinel structure is partially occupied by the excess Mg in the synthesized sample. This structural feature might result in a stable charge/discharge cycle performance of the Mg-rich Mg-Fe-O.

Genetic Mapping of the HLA1 Locus Causing Hybrid Lethality in Nicotiana Interspecific Hybrids.

Hybrid lethality, a postzygotic mechanism of reproductive isolation, is a phenomenon that causes the death of F1 hybrid seedlings. Hybrid lethality is generally caused by the epistatic interaction of two or more loci. In the genus Nicotiana, N. debneyi has the dominant allele Hla1-1 at the HLA1 locus that causes hybrid lethality in F1 hybrid seedlings by interaction with N. tabacum allele(s). Here, we mapped the HLA1 locus using the F2 population segregating for the Hla1-1 allele derived from the interspecific cross between N. debneyi and N. fragrans. To map HLA1, several DNA markers including random amplified polymorphic DNA, amplified fragment length polymorphism, and simple sequence repeat markers, were used. Additionally, DNA markers were developed based on disease resistance gene homologs identified from the genome sequence of N. benthamiana. Linkage analysis revealed that HLA1 was located between two cleaved amplified polymorphic sequence markers Nb14-CAPS and NbRGH1-CAPS at a distance of 10.8 and 10.9 cM, respectively. The distance between these markers was equivalent to a 682 kb interval in the genome sequence of N. benthamiana.

Synthesis, Crystal Structure Analysis, and Electrochemical Properties of Rock-Salt Type Mg xNi yCo zO2 as a Cathode Material for Mg Rechargeable Batteries.

Research has recently been focused on high-performance next-generation batteries to replace secondary batteries due to capacity limitations and safety concerns. The Mg secondary battery is one candidate to realize high energy density storage batteries for practical applications. Ni and Co typically exhibit desirable electrochemical characteristics; therefore, we have attempted to synthesize new rock-salt compositions, Mg xNi yCo zO2 ( x + y + z ≤ 2.0), as cathode materials for Mg rechargeable batteries, and investigated their crystal structures and electrochemical characteristics. The materials were synthesized by the reverse coprecipitation method. Powder X-ray diffraction and transmission electron microscopy analyses showed the obtained samples were a single phase of the rock-salt structure with the space group Fm3̅ m. The vacancies at the metal sites were estimated by Rietveld analysis to determine the new chemical composition of Mg xNi yCo z□2- x- y- zO2 (0.41 < x < 0.64, 0.82 < y < 1.23, 0.24 < z < 0.61). Charge-discharge tests indicated the discharge characteristics varied according to the Mg composition and the Ni/Co ratio. The Co and Mg compositions were considered to facilitate the insertion/deinsertion of Mg2+. The present new material has the potential to be a superior cathode material for Mg secondary batteries by first-principles calculations.

Enhanced oxide-ion conductivity of solid-state electrolyte mesocrystals.

Oxide ion-conducting porous films were produced on a substrate by evaporation-induced self-assembly of rare earth-doped CeO2 (REDC) nanocubes 4-5 nm in size and subsequent mild calcination at 400 °C. Mesocrystalline structures comprising iso-oriented REDC nanocubes were formed by ordered assembly based on strict attachment of their {100} faces. Enhanced oxide-ion conductivities in a temperature range of 250-350 °C were observed on the mesocrystalline films consisting of Sm-doped CeO2 (SDC) nanocubes. The specific electrical properties of the mesocrystalline films are ascribed to improved surface-ion conduction due to a large specific surface area and a high crystallographic connectivity of SDC nanocubes.

The atomic structure of a MgCo2O4 nanoparticle for a positive electrode of a Mg rechargeable battery.

The atomic structure of a spinel-type MgCo2O4 nanoparticle was investigated by the reverse Monte Carlo modelling using X-ray and neutron total scattering data. It is found that Mg at an octahedral site induces a significant structural distortion, while Mg at a tetrahedral site is considered to move easily to a vacant site. Based on the results, we propose a guideline for the development of a better positive electrode material for a Mg rechargeable battery.

Solution Plasma Process-Derived Defect-Induced Heterophase Anatase/Brookite TiO2 Nanocrystals for Enhanced Gaseous Photocatalytic Performance.

We report a simple room-temperature synthesis route for increasing the reactivity of a TiO2 photocatalyst using a solution plasma process (SPP). Hydrogen radicals generated from the SPP chamber interact with the TiO2 photocatalyst feedstock, transforming its crystalline phase and introducing oxygen vacancy defects. In this work, we examined a pure anatase TiO2 as a model feedstock because of its photocatalytic attributes and well-characterized properties. After the SPP treatment, the pure anatase crystalline phase was transformed to an anatase/brookite heterocrystalline phase with oxygen vacancies. Furthermore, the SPP treatment promoted the absorption of both UV and visible light by TiO2. As a result, TiO2 treated by the SPP for 3 h showed a high gaseous photocatalytic performance (91.1%) for acetaldehyde degradation to CO2 compared with the activity of untreated TiO2 (51%). The SPP-treated TiO2 was also more active than nitrogen-doped TiO2 driven by visible light (66%). The overall photocatalytic performance was related to the SPP treatment time. The SPP technique could be used to enhance the activity of readily available feedstocks with a short processing time. These results demonstrate the potential of this method for modifying narrow-band gap metal oxides, metal sulfides, and polymer composite-based catalyst materials. The modifications of these materials are not limited to photocatalysts and could be used in a wide range of energy and environment-based applications.

Mechanochemically Prepared Li2S-P2S5-LiBH4 Solid Electrolytes with an Argyrodite Structure.

Solid electrolytes with compositions of (100 - x)(0.75Li2S·0.25P2S5)·xLiBH4 (mol %, 0 ≤ x ≤ 100) were mechanochemically prepared from the 75Li2S·25P2S5 (mol %) glass and LiBH4 crystal. The samples with x ≥ 43 have crystalline phases and those with x ≤ 33 formed a glassy phase. The crystalline phase was identified as argyrodite Li6PS5(BH4). The x = 50 sample formed a crystalline phase and demonstrated a high lithium-ion conductivity of 1.8 × 10-3 S cm-1 at 25 °C with an activation energy of 16 kJ·mol-1. The argyrodite-type crystal with a BH4 - anion that occupies the halide site is a novel and promising solid electrolyte.

Signalling via the osteopontin and high mobility group box-1 axis drives the fibrogenic response to liver injury.

OBJECTIVE: Liver fibrosis is associated with significant collagen-I deposition largely produced by activated hepatic stellate cells (HSCs); yet, the link between hepatocyte damage and the HSC profibrogenic response remains unclear. Here we show significant induction of osteopontin (OPN) and high-mobility group box-1 (HMGB1) in liver fibrosis. Since OPN was identified as upstream of HMGB1, we hypothesised that OPN could participate in the pathogenesis of liver fibrosis by increasing HMGB1 to upregulate collagen-I expression. DESIGN AND RESULTS: Patients with long-term hepatitis C virus (HCV) progressing in disease stage displayed enhanced hepatic OPN and HMGB1 immunostaining, which correlated with fibrosis stage, whereas it remained similar in non-progressors. Hepatocyte cytoplasmic OPN and HMGB1 expression was significant while loss of nuclear HMGB1 occurred in patients with HCV-induced fibrosis compared with healthy explants. Well-established liver fibrosis along with marked induction of HMGB1 occurred in CCl4-injected OpnHep transgenic yet it was less in wild type and almost absent in Opn-/- mice. Hmgb1 ablation in hepatocytes (Hmgb1ΔHep) protected mice from CCl4-induced liver fibrosis. Coculture with hepatocytes that secrete OPN plus HMGB1 and challenge with recombinant OPN (rOPN) or HMGB1 (rHMGB1) enhanced collagen-I expression in HSCs, which was blunted by neutralising antibodies (Abs) and by Opn or Hmgb1 ablation. rOPN induced acetylation of HMGB1 in HSCs due to increased NADPH oxidase activity and the associated decrease in histone deacetylases 1/2 leading to upregulation of collagen-I. Last, rHMGB1 signalled via receptor for advanced glycation end-products and activated the PI3K-pAkt1/2/3 pathway to upregulate collagen-I. CONCLUSIONS: During liver fibrosis, the increase in OPN induces HMGB1, which acts as a downstream alarmin driving collagen-I synthesis in HSCs.

Osteopontin is a proximal effector of leptin-mediated non-alcoholic steatohepatitis (NASH) fibrosis.

INTRODUCTION: Liver fibrosis develops when hepatic stellate cells (HSC) are activated into collagen-producing myofibroblasts. In non-alcoholic steatohepatitis (NASH), the adipokine leptin is upregulated, and promotes liver fibrosis by directly activating HSC via the hedgehog pathway. We reported that hedgehog-regulated osteopontin (OPN) plays a key role in promoting liver fibrosis. Herein, we evaluated if OPN mediates leptin-profibrogenic effects in NASH. METHODS: Leptin-deficient (ob/ob) and wild-type (WT) mice were fed control or methionine-choline deficient (MCD) diet. Liver tissues were assessed by Sirius-red, OPN and αSMA IHC, and qRT-PCR for fibrogenic genes. In vitro, HSC with stable OPN (or control) knockdown were treated with recombinant (r)leptin and OPN-neutralizing or sham-aptamers. HSC response to OPN loss was assessed by wound healing assay. OPN-aptamers were also added to precision-cut liver slices (PCLS), and administered to MCD-fed WT (leptin-intact) mice to determine if OPN neutralization abrogated fibrogenesis. RESULTS: MCD-fed WT mice developed NASH-fibrosis, upregulated OPN, and accumulated αSMA+ cells. Conversely, MCD-fed ob/ob mice developed less fibrosis and accumulated fewer αSMA+ and OPN+ cells. In vitro, leptin-treated HSC upregulated OPN, αSMA, collagen 1α1 and TGFß mRNA by nearly 3-fold, but this effect was blunted by OPN loss. Inhibition of PI3K and transduction of dominant negative-Akt abrogated leptin-mediated OPN induction, while constitutive active-Akt upregulated OPN. Finally, OPN neutralization reduced leptin-mediated fibrogenesis in both PCLS and MCD-fed mice. CONCLUSION: OPN overexpression in NASH enhances leptin-mediated fibrogenesis via PI3K/Akt. OPN neutralization significantly reduces NASH fibrosis, reinforcing the potential utility of targeting OPN in the treatment of patients with advanced NASH.

[Association of sleep problems with self-rated health - a large epidemiologic survey in the working population].

To investigate the association between various sleep problems and self-rated health (SRH), a total of 43,092 (34,164 men and 8,928 women) employees were surveyed by means of a self-administered questionnaire. The risk of suboptimal (poor, very poor) SRH associated with sleep problems was estimated using multivariable logistic regression with odds ratios (ORs) as measures of associations. Because the prevalence of suboptimal SRH differed by sex (men 29.4% and women 34.1%, P < 0.001), the analyses were done separately for men and women. Employees sleeping less than 6 hrs/day (OR = 1.39 for men, 1.40 for women), with difficulty initiating sleep (OR=4.44 for men, 3.85 for women), with difficulty maintaining sleep (OR=5.72 for men, 4.85 for women), with early morning awakening (OR=3.87 for men, 4.25 for women), with difficulty waking up in the morning (OR=3.30 for men, 3.40 for women), feeling tired when waking up in the morning (OR=4.97 for men, 4.82 for women), and excessive daytime sleepiness at work (OR=2.34 for men, 2.11 for women) had a significantly higher odds of suboptimal SRH compared to those without sleep problems. The association between sleep problems and suboptimal SRH did not differ between men and women. In conclusion, the data point to an independent relationship between sleep problems and suboptimal SRH among Japanese employees.

Osteopontin induces ductular reaction contributing to liver fibrosis.

OBJECTIVE: In human chronic liver disease, there is association between ductular reaction (DR) and fibrosis; yet, the mechanism triggering its onset and its role in scar formation remains unknown. Since we previously showed that osteopontin (OPN) is highly induced during drug-induced liver fibrosis, we hypothesised that OPN could drive oval cells (OC) expansion and DR and signal to hepatic stellate cells (HSC) to promote scarring. RESULTS: In vivo studies demonstrated increased OPN expression in biliary epithelial cells (BEC) and in OC in thioacetamide (TAA)-treated mice. OPN ablation protected mice from TAA and bile duct ligation-induced liver injury, DR and scarring. This was associated with greater hepatocyte proliferation, lower OC expansion and DR along with less fibrosis, suggesting that OPN could activate the OC compartment to differentiate into BEC, which could then signal to HSC to enhance scarring. Since TAA-treated wild-type mice and cirrhotic patients showed TGF-ß(+) BEC, which were lacking in TAA-treated Opn(-/-) mice and in healthy human explants, this suggested that OPN could regulate TGF-ß, a profibrogenic factor. In vitro experiments confirmed that recombinant OPN (rOPN) decreases hepatocyte proliferation and increases OC and BEC proliferation. To evaluate how BEC regulate collagen-I production in HSC, co-cultures were established. Co-cultured BEC upregulated OPN and TGF-ß expression and enhanced collagen-I synthesis by HSC. Lastly, recombinant TGF-ß (rTGFß) and rOPN promoted BEC proliferation and neutralisation of OPN and TGF-ß reduced collagen-I expression in co-cultured HSC. CONCLUSIONS: OPN emerges as a key matricellular protein driving DR and contributing to scarring and liver fibrosis via TGF-ß.

Osteopontin delays resolution of liver fibrosis.

To date, considerable progress has been made both in the mechanisms driving liver fibrosis and in the prevention of disease progression. Resolution of liver fibrosis is an emerging field in hepatology; yet, the mediators involved remain elusive. Earlier work from our laboratory demonstrated that the matricellular cytokine osteopontin (OPN) is pro-fibrogenic by promoting hepatic stellate cell (HSC) activation and extracellular matrix (ECM) deposition in vitro and in vivo and specifically by governing fibrillar collagen-I expression, the key pro-fibrogenic protein. Here we hypothesized that OPN could also delay the resolution of liver fibrosis by sustaining collagen-I synthesis or by preventing its degradation. To demonstrate this, wild-type (WT) and OPN-knockout (Opn(-/-)) mice were administered thioacetamide (TAA) in the drinking water for 4 months. Half of the mice were killed at 4 months to assess the extent of fibrosis at the peak of injury, and the rest of the mice were killed 2 months after TAA withdrawal to determine the rate of fibrosis resolution. Following TAA cessation, livers from Opn(-/-) mice showed no centrilobular and parenchymal necrosis along with faster ECM remodeling than WT mice. The latter was quantified by less fibrillar collagen-I immunostaining. Western blot analysis demonstrated a significant decrease in fibrillar collagen-I and in tissue inhibitor of metalloproteinase-1 (TIMP-1) in Opn(-/-) mice undergoing fibrosis resolution compared with WT mice. In conclusion, these results suggest that OPN delays liver fibrosis resolution due to sustained fibrillar collagen-I deposition; hence, inhibiting OPN could be an effective therapeutic strategy for resolving liver fibrosis.

Comparison of animal studies between interstitial magnetic resonance lymphography and radiocolloid SPECT/CT lymphoscintigraphy in the head and neck region.

OBJECTIVE: To comparatively assess two techniques, radiocolloid SPECT/CT lymphoscintigraphy and interstitial MR lymphography using SPIO and gadoxetate disodium, in animal models. MATERIALS AND METHODS: We used twenty one 8-week-old male nude mice of strain BALB/c Slc-nu/nu, weighing 23-27 g. The 4.7-T MRI equipment was used to detect the SNs. T2*WI of gradient-echo sequences was acquired sequentially up to 24 h after administering SPIO, ferucarbotran. T1WI was acquired sequentially up to 80 min after administering gadoxetate disodium. (99m)Tc-phytate SPECT/CT lymphoscintigraphy was taken at 30 min after the injection to detect the SNs using animal-dedicated whole-body SPECT/CT hybrid scanner. The injection was submucosally performed in the right tongue margin of each mouse. Reading performances concerning SN visualization and its quality on interstitial MR lymphogram and SPECT/CT lymphoscintigram were performed by 3 radiologists. RESULTS: The SN intensities were 0.43 for the right, 0.61 for the left at 30 min after ferucarbotran injection, with gradual decrease in intensity, and 1.43 for the right, 1.33 for the left at 10 min after gadoxetate disodium injection with a fast decrease in intensity. The base value of 1.0 was at pre-examination. The mean numbers of lymph nodes visualized were 4.00 nodes for on SPECT/CT lymphoscintigram and 2.0 for interstitial MR lymphogram. There was a statistically significant difference in the mean scores between SPECT/CT lymphoscintigraphy and interstitial MR lymphography (two factor mixed design with repeated measures on one factor: p < 0.0002). CONCLUSIONS: In our comparative study using mice, the results of radiocolloid SPECT/CT lymphoscintigraphy were superior to those of interstitial MR lymphography, while both SPIO and gadoxetate disodium have a potential of being employed for sentinel node navigation surgery by interstitial MR lymphography in the head and neck region.

[Introducing treatment for dissociative identity disorder].

This paper is a case presentation and study of the introduction of treatment for Dissociative Identity Disorder (DID). Since one manifestation of the pathology of DID is that sufferers avoid relying on others, at the start of treatment we try to stabilise the relationship between clinicians and patients; that is to say, we aim to build a treatment relationship which will be able to gradually overcome the patients' dread of relying on clinicians. In parallel with this we undertake a thorough psychiatric assessment of their condition. This is a standard treatment plan, which follows the general principles of clinical psychiatry. On the other hand, the specialist aspect of DID treatment calls for handling the unique behaviours of a group of mutually opposed alternating personalities appropriately, while always paying consistent attention to the traumatic memories which are connected to the formation and maintenance of the condition. This paper presents the first DID case which the author has taken charge of. There were some difficulties in the early stages of treatment, but after modifying some parts to acknowledge the alternating personalities as independent personalities in face-to-face interviews and psychological education for families, the stabilisation of the treatment structure progressed gradually and the stability of the relationship between clinicians and patients itself has become the focus.

Biodistribution of immunoliposome labeled with Tc-99m in tumor xenografted mice.

OBJECTIVE: Immunoliposome (PEG, GAH, liposome; PGL), consisting of F(ab')(2) fragment of monoclonal antibody, GAH and polyethyleneglycol-coated (PEGylated) liposome was provided. Immunoliposome, PGL was labeled with technetium-99m (Tc-99m) by two methods: labeling F(ab')(2) fragment with Tc-99m; Tc-99m-PGL, and entrapping Tc-99m into liposome; PGL[Tc-99m]. The objective of this study was to compare the biodistribution of Tc-99m-PGL and PGL[Tc-99m] in human gastric cancer xenografted mice. METHODS: Tc-99m-PGL, PGL[Tc-99m], and Tc-99m-entrapped liposome; Lipo[Tc-99m] were prepared. They were injected into human gastric cancer, MKN45, xenografted mice via the tail vein, and their biodistribution was studied. RESULTS: No marked accumulation of either PGL[Tc-99m] or Lipo[Tc-99m] was observed in the stomach. The uptake of Tc-99m-PGL by the liver, spleen, and lung was higher than that by the tumor. On the other hand, the uptake of PGL[Tc-99m] by the lung and spleen was markedly lower as compared with that of Tc-99m-PGL; the accumulation of PGL[Tc-99m] was lower in the lung and higher in the spleen as compared with that of the tumor. Although the liver uptake of PGL[Tc-99m] was markedly decreased as compared with that of Tc-99m-PGL, it was higher than the uptake of the tumor. The Tc-99m-PGL was strongly taken up by the tumor, with a high level of incorporation also seen in the stomach. These findings suggest the need for further study of the labeling stability. CONCLUSIONS: PGL[Tc-99m] appears to show promise for high tumor uptake and retention. This is an important implication for the potential application of immunoliposomes entrapped with Re-186, instead of Tc-99m, in internal radiotherapy.

Utility of quantitative 99mTc-phytate scintigraphy to diagnose early-stage non-alcoholic steatohepatitis.

OBJECTIVE: In patients with non-alcoholic fatty liver disease (NAFLD), liver biopsy remains the only reliable method to differentiate simple steatosis from non-alcoholic steatohepatitis (NASH). The objective of this study was to evaluate the efficacy of non-invasive (99m)Tc-phytate scintigraphy in the diagnosis of NASH. MATERIAL AND METHODS: Thirty-seven patients with suspected NAFLD at the time of liver biopsy also underwent (99m)Tc-phytate scintigraphy. Signal intensities of regions of interest (ROI) in the liver, spleen, and heart were measured. We also examined scintigraphic features in a nutritional model of NASH in rats fed a methionine- and choline-deficient (MCD) diet. RESULTS: The liver/spleen uptake ratio determined by scintigraphy was significantly decreased in patients with NASH in comparison with patients with simple steatosis. The liver/spleen ratio was an independent predictor distinguishing NASH from simple steatosis. The decrease was observed for all stages of NASH, including the early stage (stages 1 and 0). In animal studies, the liver/spleen uptake ratio was significantly decreased in rats after 8 weeks of MCD dietary feeding in comparison with control diet-fed rats. CONCLUSIONS: The non-invasive (99m)Tc-phytate scintigraphy test is a reliable tool to differentiate NASH from simple steatosis.

Predictors to assess non-sentinel lymph node status in breast cancer patients with sentinel lymph node metastasis.

The next step of sentinel lymph node biopsy (SLNB) in breast cancer is to determine which patients need axillary lymph node dissection (ALND) following a positive SLNB. A prospective database of 239 patients who underwent SLNB followed by complete ALND at Keio University Hospital from January 2001 to June 2005 was reviewed. A total of 131 patients with one or more positive sentinel lymph nodes (SLNs) were further analyzed. A univariate analysis showed a significant correlation between non-SLN involvement and lymphatic invasion, vascular invasion, number of tumor-involved SLNs, radioactivity of SLNs, and size of SLN metastasis (p = 0.0002, p = 0.004, p = 0.006, p = 0.04, p = 0.03, respectively). By multivariate analysis, lymphatic invasion and the number of tumor-involved SLNs remained significant predictors of non-SLN involvement. In breast cancer patients with a positive SLN, lymphatic invasion and the number of tumor-involved SLNs were both independent predictors of non-SLN involvement.

Application of support vector machine classifiers to preoperative risk stratification with myocardial perfusion scintigraphy.

BACKGROUND: Myocardial perfusion single-photon emission computed tomography (SPECT) has been used for risk stratification before non-cardiac surgery. However, few authors have used mathematical models for evaluating the likelihood of perioperative cardiac events. METHODS AND RESULTS: This retrospective cohort study collected data of 1,351 patients referred for SPECT before non-cardiac surgery. We generated binary classifiers using support vector machine (SVM) and conventional linear models for predicting perioperative cardiac events. We used clinical and surgical risk, and SPECT findings as input data, and the occurrence of all and hard cardiac events as output data. The area under the receiver-operating characteristic curve (AUC) was calculated for assessing the prediction accuracy. The AUC values were 0.884 and 0.748 in the SVM and linear models, respectively in predicting all cardiac events with clinical and surgical risk, and SPECT variables. The values were 0.861 (SVM) and 0.677 (linear) when not using SPECT data as input. In hard events, the AUC values were 0.892 (SVM) and 0.864 (linear) with SPECT, and 0.867 (SVM) and 0.768 (linear) without SPECT. CONCLUSION: The SVM was superior to the linear model in risk stratification. We also found an incremental prognostic value of SPECT results over information about clinical and surgical risk.

Preoperative risk evaluation in diabetic patients without angina.

AIMS: The aim of the current study was to clarify whether stress myocardial perfusion single-photon emission computed tomography (SPECT) stratifies perioperative cardiac risk in noncardiac surgery of diabetic patients without chest pain. METHODS: This study enrolled consecutive 284 patients with diabetes mellitus (DM) without chest pain who underwent noncardiac surgery after dipyridamole stress SPECT. Myocardial perfusion and cardiac function were simultaneously evaluated in the SPECT examination. We sought clinical and imaging variables predictive of perioperative cardiac events, and estimated the prognostic value of SPECT. RESULTS: No clinical risk factors were proved to be significant predictors of perioperative cardiac events except the duration of diabetes. In contrast, myocardial perfusion imaging itself and the combination of information on perfusion and cardiac function provided significant risk stratification. The event rate in patients with normal perfusion was low regardless of surgical procedures, while that in patients with abnormal perfusion increased depending on the operation risk. CONCLUSIONS: Normal myocardial SPECT findings ensure the low likelihood of perioperative cardiac events in DM patients without chest pain. Perfusion and/or functional abnormalities are associated with the adverse outcome especially in high-risk operation.