Efficient high-power dual-wavelength lime-green Nd:YVO4 lasers

An efficient high-power dual-wavelength lime-green Nd:YVO₄ self-Raman laser is inventively developed by using two different lithium triborate (LBO) crystals. The first and second LBO crystals are employed to generate the 559 nm lime and 532 nm green lasers, respectively. The temperature of the first LBO crystal is fixed at the optimal phase matching, whereas the temperature of the second LBO crystal is tuned to flexibly control the relative strengths between the 532 and 559 nm waves. When the temperature of the second LBO crystal is set for the maximal total output power, the 532 and 559 nm output powers, respectively, are 7.1 and 2.9 W at a pump power of 31.6 W, corresponding to a conversion efficiency of 31.6%. When the temperature is controlled for the balanced output, the 532 and 559 nm powers, respectively, are 4.3 and 4.2 W at a pump power of 31.6 W, corresponding to a conversion efficiency of 26.9%.

Efficient high-power continuous-wave lasers at green-lime-yellow wavelengths by using a Nd:YVO4 self-Raman crystal

Efficient high-power continuous-wave Nd:YVO₄ visible lasers at versatile wavelengths of 532 (green), 559 (lime), and 588 nm (yellow) are demonstrated to be achieved by using the identical cavity mirrors and gain medium. A dichroic coating is deposited on one end surface of the gain medium to gather the backward green-yellow emission. The green, lime, and yellow outputs are individually optimized by using different phase-matched lithium triborate (LBO) crystals for second harmonic generation (SHG) of the fundamental field, sum frequency generation (SFG) of the fundamental and the stimulated Raman fields, and SHG of the stimulated Raman field, respectively. At a pump power of 31.6 W, the output powers at 532, 559, and 588 nm can be up to 6.8, 5.4, and 3.1 W. The high efficient and compact Nd:YVO₄ lasers at green-lime-yellow wavelengths can be potentially beneficial to future applications in retinal photocoagulation.

Expression profiles and potential functions of circular RNAs in extracellular vesicles isolated from radioresistant glioma cells

The molecular mechanisms of circular RNAs (circRNAs) in extracellular vesicles (EVs) associated with glioma radioresistance remain unknown. The aim of the present study was to assess the differential circRNA expression profiles between EVs isolated from U251 cells and EVs isolated from radioresistant U251 (RR‑U251) cells. Identified circRNAs in EVs isolated from RR‑U251 cells (RR‑EVs) act as a U251 microRNA (miRNA) sponge. The circRNA expression was determined using RNA sequencing (RNA‑seq) technique. A total of 1,235 circRNAs were detected. We identified 63 upregulated and 48 downregulated circRNAs in RR‑EVs compared with those from U251 cells (Nor‑EVs). The expression level of candidate circATP8B4 was confirmed using real‑time quantitative PCR. It was significantly higher in RR‑EVs than in Nor‑EVs. Expression profile of RR‑U251 and U251 miRNAs was conducted. miRanda and RNAhybrid softwares was used to predict the U251 downregulated miRNAs interacting with circATP8B4. CircATP8B4 from RR‑EVs may be transferred to normal glioma U251 cells and act as an miR‑766 sponge to promote cell radioresistance. In conclusion, using RNA‑seq and bioinformatics, it was found that circATP8B4 in RR‑EVs acts as a U251 miR‑766 sponge, which may be involved in glioma radioresistance.

[Cause and control of non-sampling error in China National Human Biomonitoring Program]

The size of the non-sampling error is directly related to the accuracy and reliability of the sampling survey result. This paper studied the non-sampling errors generated during the sampling process of the China National Human Biomonitoring Program(CNBP), mainly including the sampling frame error, non-response error and measurement error. The program reduced the influence of the non-sampling error on the quality of the survey effectively by scientifically designing the sampling scheme and questionnaire, strengthening investigator trainings and standardizing the data review, which could be used to provide reference for the control of non-sampling errors in public health monitoring projects in China.

Cardiac Magnetic Resonance Fingerprinting: Technical Overview and Initial Results

Cardiovascular magnetic resonance is a versatile tool that enables noninvasive characterization of cardiac tissue structure and function. Parametric mapping techniques have allowed unparalleled differentiation of pathophysiological differences in the myocardium such as the delineation of myocardial fibrosis, hemorrhage, and edema. These methods are increasingly used as part of a tool kit to characterize disease states such as cardiomyopathies and coronary artery disease more accurately. Currently conventional mapping techniques require separate acquisitions for T1 and T2 mapping, the values of which may depend on specifics of the magnetic resonance imaging system hardware, pulse sequence implementation, and physiological variables including blood pressure and heart rate. The cardiac magnetic resonance fingerprinting (cMRF) technique has recently been introduced for simultaneous and reproducible measurement of T1 and T2 maps in a single scan. The potential for this technique to provide consistent tissue property values independent of variables including scanner, pulse sequence, and physiology could allow an unbiased framework for the assessment of intrinsic properties of cardiac tissue including structure, perfusion, and parameters such as extracellular volume without the administration of exogenous contrast agents. This review seeks to introduce the basics of the cMRF technique, including pulse sequence design, dictionary generation, and pattern matching. The potential applications of cMRF in assessing diseases such as nonischemic cardiomyopathy are also briefly discussed, and ongoing areas of research are described.

Role of HMGB1 in Post-traumatic Endoplasmic Reticulum Stress in Rat Lung Tissues

OBJECTIVES

To explore the role of high mobility group B1 （HMGB1） protein in the post-traumatic endoplasmic reticulum stress （ERS） in rat lung tissues.

METHODS

The rat model of acute lung injury was established by crushing the hind limbs of rats with standard weight. The first experiment was to divide rats into postural control group and crush groups （6 h, 18 h and 30 h after crushing）. The second experiment was to divide rats into postural control group, 18 h crush group, HMGB1 inhibitor sodium butyrate （SB） group and 18 h crush+SB group. The protein expression changes of HMGB1 and ERS- related proteins （GRP78, caspase-12, CHOP and IRE1α） in rat lung tissues were detected with Western blotting. Meanwhile, the pathological changes of rat lungs were observed by HE stain.

RESULTS

Compared with the postural control group, the expression levels of ERS-related proteins （GRP78, caspase-12, CHOP and IRE1α） and HMGB1 protein in rat lung tissues by crushing the hind limbs of rats were obviously increased. The protein levels reduced at 30 h after crushing but were still higher than those of postural control group and obvious pathological changes of acute lung injury were observed simultaneously in rats. Compared with the 18 h crush group, the expression levels of the ERS-related proteins and HMGB1 protein in rat lung tissues were attenuated in 18 h crush+SB group, and the pathological changes of rat lung injury began to alleviate.

CONCLUSIONS

HMGB1-ERS pathway activated by traumatic stress can lead to acute lung injury in rats.

[The relationship between IL-4 and trace elements in patients with allergic rhinitis of hui and han populations in Ningxia]

Objective: To examine the relationship between trace elements and IL-4 in patients with allergic rhinitis(AR).Method:According to the inclusion and exclusion criteria, a total of 260 cases in AR group(130 hui cases, 130 han cases),and 260 cases in normal control group(130 hui cases, 130 han cases) were recruited in this study. The concentrations of IL-4 were detected by enzyme linked immunosorbent assay(ELISA), the contents of Zn, Mn, Ni, Se and Fe were determined by inductively coupled plasma atomic emission spectrometry(ICP-AES), and the correlation between the trace elements and IL-4 were also analyzed.Result:IL-4 levels in serum of both hui and han AR patients were higher than those in control group(P <0.05). Contents of serum Zn and Se in hui AR patients were lower than those in control group(P <0.05), Ni content was higher than that in control group(P <0.05);Zn level in serum of han AR cases was lower than that in control group,Ni content was higher than that in control group (P <0.05).The serum IL-4 level in AR group was positively correlated with Ni(P <0.01,r=0.671), and negatively correlated with Zn(P <0.01, r=-0.819).Conclusion:We demonstrated that there are significant correlations between IL-4 and Zn,Ni in the serum of patients with AR in Ningxia hui and han population. It indicates that trace elements are involved in the occurrence and development of AR, and may as a therauptic target of AR.

Flexible modulation of electronic and magnetic properties of zigzag H-MoS2 nanoribbons by crack defects

The effects of crack defects on electronic and magnetic properties of zigzag MoS₂ nanoribbons are investigated systematically by first-principles calculations based on spin-polarized density functional theory. We find that not only the electronic and spin transport ability of zigzag MoS₂ nanoribbons can be enhanced significantly by the armchair crack defects, but also their magnetism could be modulated flexibly by crack defects. Our study suggests that the introduction of crack defect is a feasible way to modulate the electronic and magnetic properties of zigzag MoS₂ nanoribbons. We further propose that the crack defects may also provide a useful tool for improving the performance of devices.

Fast magnetic resonance fingerprinting for dynamic contrast-enhanced studies in mice

PURPOSE

The goal of this study was to develop a fast MR fingerprinting (MRF) method for simultaneous T₁ and T₂ mapping in DCE-MRI studies in mice.

METHODS

The MRF sequences based on balanced SSFP and fast imaging with steady-state precession were implemented and evaluated on a 7T preclinical scanner. The readout used a zeroth-moment-compensated variable-density spiral trajectory that fully sampled the entire k-space and the inner 10 × 10 k-space with 48 and 4 interleaves, respectively. In vitro and in vivo studies of mouse brain were performed to evaluate the accuracy of MRF measurements with both fully sampled and undersampled data. The application of MRF to dynamic T₁ and T₂ mapping in DCE-MRI studies were demonstrated in a mouse model of heterotopic glioblastoma using gadolinium-based and dysprosium-based contrast agents.

RESULTS

The T₁ and T₂ measurements in phantom showed strong agreement between the MRF and the conventional methods. The MRF with spiral encoding allowed up to 8-fold undersampling without loss of measurement accuracy. This enabled simultaneous T₁ and T₂ mapping with 2-minute temporal resolution in DCE-MRI studies.

CONCLUSION

Magnetic resonance fingerprinting provides the opportunity for dynamic quantification of contrast agent distribution in preclinical tumor models on high-field MRI scanners.

Arabidopsis Serine Decarboxylase 1 (SDC1) in Phospholipid and Amino Acid Metabolism

Arabidopsis thaliana serine decarboxylase 1 (SDC1) catalyzes conversion of serine to ethanolamine, the first reaction step of phosphatidylcholine and phosphatidylethanolamine biosynthesis. However, an involvement of SDC1 in amino acid metabolism remains elusive despite that serine is the substrate of SDC1. Here, we showed that SDC1 localizes in mitochondria although phosphatidylcholine and phosphatidylethanolamine are known to be produced in the endoplasmic reticulum (ER). Moreover, we found that overexpression of SDC1 decreased levels of amino acid compounds derived from mitochondrial tricarboxylic acid cycle. These results suggest that mitochondria-localized SDC1 plays an important role in both phospholipid and amino acid metabolism in A. thaliana.

Blunt Traumatic Cardiac Rupture Presenting as Massive Haemothorax

Cardiac rupture following blunt thoracic trauma in motor vehicle crash generally causes death at scene, and is rarely diagnosed preoperatively. However, early emergency thoracotomy in the emergency department (ED) or operating room might reduce the mortality but the benefit is still controversial. A haemodynamically unstable 28-year-old woman following motor vehicle crash was detected to have right haemothorax on chest X-ray. Thoracic computed tomography (CT) revealed additional lung contusions and multiple bone fractures. She developed cardiac arrest during open thoracotomy and had restored spontaneous circulation after open-chest cardiopulmonary resuscitation (CPR). This report highlights that CT scan in haemodynamically unstable patients could delay surgical control of the injury. Open-chest CPR can be life-saving for blunt chest injury developing cardiac arrest. (Hong Kong j.emerg.med. 2015;22:320-323)

[Microdeletion and Mutation of Y Chromosome in Full Sibling Identification]

OBJECTIVES

To explore the identification method of full sibling between two males with microdeletion and mutation of Y chromosome.

METHODS

DNA were extracted from two samples. The type testing of Y-STR and autosomal STR were performed. Full sibling between two individuals was calculated by IBS, ITO and discriminant functions methods.

RESULTS

There were 2 loci mutations existed in 33 Y-STR loci and one of the two samples had 19 loci deletions. The IBS of two samples was 53 and greater than the threshold which was 42; FSI was 1.36×10¹⁶ and far greater than 19. The discriminant function of full sibling-unrelated individual D_FS2 was greater than D_R2, which meant the two individuals tend to be full sibling.

CONCLUSIONS

The methods of IBS, ITO and discriminant functions of full sibling-unrelated individual can be used comprehensively to provide more reliable expert opinion in microdeletion and mutation of Y chromosome in full sibling identification.

31 P magnetic resonance fingerprinting for rapid quantification of creatine kinase reaction rate in vivo

The purpose of this work was to develop a 31 P spectroscopic magnetic resonance fingerprinting (MRF) method for fast quantification of the chemical exchange rate between phosphocreatine (PCr) and adenosine triphosphate (ATP) via creatine kinase (CK). A 31 P MRF sequence (CK-MRF) was developed to quantify the forward rate constant of ATP synthesis via CK ( kfCK), the T1 relaxation time of PCr ( T1PCr), and the PCr-to-ATP concentration ratio ( MRPCr). The CK-MRF sequence used a balanced steady-state free precession (bSSFP)-type excitation with ramped flip angles and a unique saturation scheme sensitive to the exchange between PCr and γATP. Parameter estimation was accomplished by matching the acquired signals to a dictionary generated using the Bloch-McConnell equation. Simulation studies were performed to examine the susceptibility of the CK-MRF method to several potential error sources. The accuracy of nonlocalized CK-MRF measurements before and after an ischemia-reperfusion (IR) protocol was compared with the magnetization transfer (MT-MRS) method in rat hindlimb at 9.4 T (n = 14). The reproducibility of CK-MRF was also assessed by comparing CK-MRF measurements with both MT-MRS (n = 17) and four angle saturation transfer (FAST) (n = 7). Simulation results showed that CK-MRF quantification of kfCK was robust, with less than 5% error in the presence of model inaccuracies including dictionary resolution, metabolite T2 values, inorganic phosphate metabolism, and B1 miscalibration. Estimation of kfCK by CK-MRF (0.38 ± 0.02 s-1 at baseline and 0.42 ± 0.03 s-1 post-IR) showed strong agreement with MT-MRS (0.39 ± 0.03 s-1 at baseline and 0.44 ± 0.04 s-1 post-IR). kfCK estimation was also similar between CK-MRF and FAST (0.38 ± 0.02 s-1 for CK-MRF and 0.38 ± 0.11 s-1 for FAST). The coefficient of variation from 20 s CK-MRF quantification of kfCK was 42% of that by 150 s MT-MRS acquisition and was 12% of that by 20 s FAST acquisition. This study demonstrates the potential of a 31 P spectroscopic MRF framework for rapid, accurate and reproducible quantification of chemical exchange rate of CK in vivo.

Assessing tissue metabolism by phosphorous-31 magnetic resonance spectroscopy and imaging: a methodology review

Many human diseases are caused by an imbalance between energy production and demand. Magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) provide the unique opportunity for in vivo assessment of several fundamental events in tissue metabolism without the use of ionizing radiation. Of particular interest, phosphate metabolites that are involved in ATP generation and utilization can be quantified noninvasively by phosphorous-31 (31P) MRS/MRI. Furthermore, 31P magnetization transfer (MT) techniques allow in vivo measurement of metabolic fluxes via creatine kinase (CK) and ATP synthase. However, a major impediment for the clinical applications of 31P-MRS/MRI is the prohibitively long acquisition time and/or the low spatial resolution that are necessary to achieve adequate signal-to-noise ratio. In this review, current 31P-MRS/MRI techniques used in basic science and clinical research are presented. Recent advances in the development of fast 31P-MRS/MRI methods are also discussed.

MicroRNA-30a Inhibits Colorectal Cancer Metastasis Through Down-Regulation of Type I Insulin-Like Growth Factor Receptor

BACKGROUND

miR-30a expression is down-regulated and regulates tumor suppressors in various cancers.

AIM

We investigated the mechanisms underlying the biological role of miR-30a in CRC.

METHODS

MicroRNA, mRNA, and protein expression were analyzed by quantitative real-time PCR and Western blot. The migration and invasion abilities of CRC were determined by wound healing assay, and trans-well migration and invasion. A luciferase reporter assay was used to confirm the targets of miR-30a.

RESULTS

miR-30a expression was significantly down-regulated in CRC tissues and in CRC tissue with lymph node metastasis compared to CRC tissue without metastasis. Overexpression of miR-30a suppressed migration and invasion through insulin-like growth factor 1 receptor (IGF1R) in CRC cells. miR-30a suppresses IGF1R protein expression and inhibits β-catenin or p-AKT and increases E-cadherin expression. The IGF1R expression level is also up-regulated in CRC tumors and inversely correlated with miR-30a in CRC specimens.

CONCLUSIONS

miR-30a functions as a tumor-suppressive miRNA, which may provide a therapeutic strategy for metastasis of CRC.

[Progress of molecular subtypes of colorectal cancer]

Colorectal cancer is one of the leading causes of morbidity and mortality around the world. Although the staging and classification systems, such as tumor/node/metastasis (TNM) staging, are widely used in clinic, there are some limitations. For example, the patients with the same pathological type, TNM stage and treatment regimen show a completely different prognosis and outcome. In the present, molecular subtyping was concerned for a more precise and accurate staging of colorectal cancer. Herein, we reviewed the literature of the molecular subtypes of colorectal cancer in the past decades. The clinical significance of various molecular subtyping systems was evaluated and compared. It will provide reference for the precision medicine of colorectal cancer in the future.

Cofilin-1 and phosphoglycerate kinase 1 as promising indicators for glioma radiosensibility and prognosis

Glioma is a primary malignancy in central nervous system. Radiotherapy has been used as one of the standard treatments for glioma for decades. Since radioresistance can reduce the curative efficacy of radiotherapy in glioma, investigating the cause of radioresistance and predicting the tumour radiosensibility appeared particularly important. We previously reported that CFL1 and PGK1 are over-expressed in radioresistant U251 glioma cells. In this study, the level of CFL1 and PGK1 of 113 glioma tissues were measured by ELISA method. The relevance of the expression of these two proteins to radiosensibility was analyzed by mean test and multivariate logistic regression. The survival analysis was carried out in 85 irradiated patients and 105 followed-up patients respectively. The relationship between protein expression and clinical parameters was explored in overall 113 patients, and the correlation between CFL1 and PGK1 were determined as well. Our results showed that the expression of CFL1 and PGK1 were significantly higher (P < 0.001) in radioresistant patients than others. The multivariate Logistic regression demonstrated that the expression of CFL1 (p < 0.001) and PGK1 (p < 0.001) were associated with radioresistance in glioma. The multivariate Cox regression in overall survival suggested that CFL1 level or PGK1 level could be the independent prognosis factor for poor prognosis in 113 glioma patients. In addition, CFL1 expression was positively correlated with PGK1 expression in glioma. The results suggested that as promising indicators, CFL1 and PGK1 could be used to evaluate glioma radiosensibility and prognosis. These two proteins could also be the potential therapeutic targets of glioma.

SPECTRAL CORRECTION FACTORS FOR CONVENTIONAL NEUTRON DOSE METERS USED IN HIGH-ENERGY NEUTRON ENVIRONMENTS-IMPROVED AND EXTENDED RESULTS BASED ON A COMPLETE SURVEY OF ALL NEUTRON SPECTRA IN IAEA-TRS-403

This paper presents improved and extended results of our previous study on corrections for conventional neutron dose meters used in environments with high-energy neutrons (En > 10 MeV). Conventional moderated-type neutron dose meters tend to underestimate the dose contribution of high-energy neutrons because of the opposite trends of dose conversion coefficients and detection efficiencies as the neutron energy increases. A practical correction scheme was proposed based on analysis of hundreds of neutron spectra in the IAEA-TRS-403 report. By comparing 252Cf-calibrated dose responses with reference values derived from fluence-to-dose conversion coefficients, this study provides recommendations for neutron field characterization and the corresponding dose correction factors. Further sensitivity studies confirm the appropriateness of the proposed scheme and indicate that (1) the spectral correction factors are nearly independent of the selection of three commonly used calibration sources: 252Cf, 241Am-Be and 239Pu-Be; (2) the derived correction factors for Bonner spheres of various sizes (6"-9") are similar in trend and (3) practical high-energy neutron indexes based on measurements can be established to facilitate the application of these correction factors in workplaces.

High-resolution dynamic 31 P-MRSI using a low-rank tensor model

PURPOSE

To develop a rapid ³¹ P-MRSI method with high spatiospectral resolution using low-rank tensor-based data acquisition and image reconstruction.

METHODS

The multidimensional image function of ³¹ P-MRSI is represented by a low-rank tensor to capture the spatial-spectral-temporal correlations of data. A hybrid data acquisition scheme is used for sparse sampling, which consists of a set of "training" data with limited k-space coverage to capture the subspace structure of the image function, and a set of sparsely sampled "imaging" data for high-resolution image reconstruction. An explicit subspace pursuit approach is used for image reconstruction, which estimates the bases of the subspace from the "training" data and then reconstructs a high-resolution image function from the "imaging" data.

RESULTS

We have validated the feasibility of the proposed method using phantom and in vivo studies on a 3T whole-body scanner and a 9.4T preclinical scanner. The proposed method produced high-resolution static ³¹ P-MRSI images (i.e., 6.9 × 6.9 × 10 mm³ nominal resolution in a 15-min acquisition at 3T) and high-resolution, high-frame-rate dynamic ³¹ P-MRSI images (i.e., 1.5 × 1.5 × 1.6 mm³ nominal resolution, 30 s/frame at 9.4T).

CONCLUSIONS

Dynamic spatiospectral variations of ³¹ P-MRSI signals can be efficiently represented by a low-rank tensor. Exploiting this mathematical structure for data acquisition and image reconstruction can lead to fast ³¹ P-MRSI with high resolution, frame-rate, and SNR. Magn Reson Med 78:419-428, 2017. © 2017 International Society for Magnetic Resonance in Medicine.

[A Study on the establishment of immune thrombocytopenia model induced by anti-platelet GPⅠbα antibodies]

Objective: To establish primary immune thrombocytopenia (ITP) animal model induced by anti-platelet membrane glycoprotein GPⅠbα antibodies AN51 and R300. Methods: Twenty guinea pigs (6-8 week) were divided into 4 groups. Five guinea pigs in each group were intravenously injected with different doses of AN51 (0.05, 0.1, 0.2 μg/g) and 0.2 μg/g IgG as control. The whole blood was collected from inner angular venous plexus. Platelets number was determined by an automated cell counter and Swiss-Jim method. Then, the similar protocol was used to establish ITP nude mice model by intraperitoneal injection of different concentrations of anti-platelet GPⅠbα antibody R300, respectively. Results: ①Five minutes after intravenous injection of AN51 at 0.05, 0.1 and 0.2 μg/g, the platelet counts of guinea pigs reduced about 0-5%, 50%-60% and 70%-80% compared to the control group, respectively. The difference was statistically significant (P<0.01) . ②Six hours after intraperitoneal injection of R300 at 0.05, 0.1, 0.2 μg/g, the platelet counts of nude mice decreased about 20%-30%, 60%-70% and 80%-90% compared to the control group, respectively. The difference was statistically significant (P<0.01) . The nude mice, injected 0.2 μg/g R300 once a day for 2 weeks, showed typical ITP clinical manifestations including large number of petechiaes or ecchymoses on limbs, head and abdomen. Conclusion: AN51 at 0.2 μg/g and R300 at 0.2 μg/g could establish stable ITP model in guinea pigs and nude mice respectively.

Mitochondrial function assessed by 31P MRS and BOLD MRI in non-obese type 2 diabetic rats

The study aims to characterize age‐associated changes in skeletal muscle bioenergetics by evaluating the response to ischemia‐reperfusion in the skeletal muscle of the Goto‐Kakizaki (GK) rats, a rat model of non‐obese type 2 diabetes (T2D). ³¹P magnetic resonance spectroscopy (MRS) and blood oxygen level‐dependent (BOLD) MRI was performed on the hindlimb of young (12 weeks) and adult (20 weeks) GK and Wistar (control) rats. ³¹P‐MRS and BOLD‐MRI data were acquired continuously during an ischemia and reperfusion protocol to quantify changes in phosphate metabolites and muscle oxygenation. The time constant of phosphocreatine recovery, an index of mitochondrial oxidative capacity, was not statistically different between GK rats (60.8 ± 13.9 sec in young group, 83.7 ± 13.0 sec in adult group) and their age‐matched controls (62.4 ± 11.6 sec in young group, 77.5 ± 7.1 sec in adult group). During ischemia, baseline‐normalized BOLD‐MRI signal was significantly lower in GK rats than in their age‐matched controls. These results suggest that insulin resistance leads to alterations in tissue metabolism without impaired mitochondrial oxidative capacity in GK rats.