Correlation between cerebral neurotransmitters levels by proton magnetic resonance spectroscopy and HbA1c in patients with type 2 diabetes

BACKGROUND Cognitive dysfunction is the main manifestation of central neuropathy.Although cognitive impairments tend to be overlooked in patients with diabetes mellitus(DM),there is a growing body of evidence linking DM to cognitive dysfunction.Hyperglycemia is closely related to neurological abnormalities,while often disregarded in clinical practice.Changes in cerebral neurotransmitter levels are associated with a variety of neurological abnormalities and may be closely related to blood glucose control in patients with type 2 DM(T2DM).AIM To evaluate the concentrations of cerebral neurotransmitters in T2DM patients exhibiting different hemoglobin A1c(HbA1c)levels.METHODS A total of 130 T2DM patients were enrolled at the Department of Endocrinology of Shanghai East Hospital.The participants were divided into four groups according to their HbA1c levels using the interquartile method,namely Q1(<7.875%),Q2(7.875%-9.050%),Q3(9.050%-11.200%)and Q4(≥11.200%).Clinical data were collected and measured,including age,height,weight,neck/waist/hip circumferences,blood pressure,comorbidities,duration of DM,and biochemical indicators.Meanwhile,neurotransmitters in the left hippocampus and left brainstem area were detected by proton magnetic resonance spectroscopy.RESULTS The HbA1c level was significantly associated with urinary microalbumin(mALB),triglyceride,low-density lipoprotein cholesterol(LDL-C),homeostasis model assessment of insulin resistance(HOMA-IR),and beta cell function(HOMA-β),N-acetylaspartate/creatine(NAA/Cr),and NAA/choline(NAA/Cho).Spearman correlation analysis showed that mALB,LDL-C,HOMA-IR and NAA/Cr in the left brainstem area were positively correlated with the level of HbA1c(P<0.05),whereas HOMA-βwas negatively correlated with the HbA1c level(P<0.05).Ordered multiple logistic regression analysis showed that NAA/Cho[Odds ratio(OR):1.608,95%confidence interval(95%CI):1.004-2.578,P<0.05],LDL-C(OR:1.627,95%CI:1.119-2.370,P<0.05),and HOMA-IR(OR:1.107,95%CI:1.031-1.188,P<0.01)were independent predictors of poor glycemic control.CONCLUSION The cerebral neurotransmitter concentrations in the left brainstem area in patients with T2DM are closely related to glycemic control,which may be the basis for the changes in cognitive function in diabetic patients.

Application of proton magnetic resonance spectroscopy in metabolic alterations of prefrontal white and gray matter in depression adolescents

BACKGROUND Cases of depression among adolescents are gradually increasing.The study of the physiological basis of cognitive function from a biochemical perspective has therefore been garnering increasing attention.Depression has been hypothesized to be associated with the brain biochemical metabolism of the anterior cingulate gyrus,frontal lobe white matter,and the thalamus.AIM To explore the application of proton magnetic resonance spectroscopy(1H-MRS)in the metabolic alterations in the prefrontal white matter(PWM)and gray matter(GM)in adolescents with depression.METHODS 1H-MRS was performed for semi-quantitative analysis of the biochemical metabolites N-acetylaspartate(NAA),choline(Cho)complexes,creatine(Cr),and myoinositol(mI)in bilateral PWM,anterior cingulate GM,and thalami of 31 adolescent patients with depression(research group)and 35 healthy adolescents(control group),and the NAA/Cr,Cho/Cr,and mI/Cr ratios were calculated.Meanwhile,Hamilton Depression Scale(HAMD)and Wechsler Memory Scale were used to assess the degree of depression and memory function in all adolescents.The correlation of brain metabolite levels with scale scores was also analyzed.RESULTS The research group had markedly higher HAMD-24 scores and lower memory quotient(MQ)compared with the control group(P<0.05).Adolescents with depression were found to have lower bilateral PWM NAA/Cr and Cho/Cr ratios compared with healthy adolescents(P<0.05).The mI/Cr ratios were found to be similar in both groups(P>0.05).The bilateral anterior cingulate GM NAA/Cr,Cho/Cr,and mI/Cr also did not demonstrate marked differences(P>0.05).No statistical inter-group difference was determined in NAA/Cr of the bilateral thalami(P>0.05),while bilateral thalamic Cho/Cr and mI/Cr were reduced in teenagers with depression compared with healthy adolescents(P<0.05).A significant negative correlation was observed between the HAMD-24 scores in adolescents with depression with bilateral PWM NAA/Cr and Cho/Cr and were inversely linked to bilateral thalamic Cho/Cr and mI/Cr(P<0.05).In adolescents with depressions,MQ positively correlated with right PWH NAA/Cr,left PWH Cho/Cr,and bilateral thalamic Cho/Cr and mI/Cr.CONCLUSION PWM and thalamic metabolic abnormalities might influence teen depression,and the reduction in bilateral PWM NAA/Cr and Cho/Cr could be related to the neuropathology of adolescents with depression suffering from memory impairment.There exists a possibility of dysfunction of nerve cell membrane phospholipids in the thalami of adolescent patients with depression.

Molecular structure characterization of middle-high rank coal via^(13)C NMR,XPS,and FTIR spectroscopy

Elemental analysis,nuclear magnetic resonance carbon spectroscopy(^(13)C-NMR),X-ray photoelectron spectroscopy(XPS)and Fourier transform infrared spectroscopy(FTIR)experiments were carried out to determine the existence of aromatic structure,heteroatom structure and fat structure in coal.MS(materials studio)software was used to optimize and construct a 3D molecular structure model of coal.A method for establishing a coal molecular structure model was formed,which was“determination of key structures in coal,construction of planar molecular structure model,and optimization of three-dimensional molecular structure model”.The structural differences were compared and analyzed.The results show that with the increase of coal rank,the dehydrogenation of cycloalkanes in coal is continuously enhanced,and the content of heteroatoms in the aromatic ring decreases.The heteroatoms and branch chains in the coal are reduced,and the structure is more orderly and tight.The stability of the structure is determined by theπ-πinteraction between the aromatic rings in the nonbonding energy EN.Key Stretching Energy The size of EB determines how tight the structure is.The research results provide a method and reference for the study of the molecular structure of medium and high coal ranks.

Estimation of unfrozen water content of saturated sandstones using nuclear magnetic resonance, mercury intrusion porosimetry, and ultrasonic tests

The unfrozenwater content(UWC)is a crucial parameter that affects the strength and thermal properties of rocks in relation to engineering construction and geological disasters in cold regions.In this study,three different methods were employed to test and estimate the UWC of saturated sandstones,including nuclear magnetic resonance(NMR),mercury intrusion porosimetry(MIP),and ultrasonic methods.The NMR method enabled the direct measurement of the UWC of sandstones using the free induction decay(FID).The MIP method was used to analyze the pore structures of sandstones,with the UWC subsequently calculated based on pore ice crystallization.Therefore,the MIP test constituted an indirect measurement method.Furthermore,a correlation was established between the P-wave velocity and the UWC of these sandstones based on the mixture theory,which could be employed to estimate the UWC as an empirical method.All methods demonstrated that the UWC initially exhibited a rapid decrease from 0C to5C and then generally became constant beyond20C.However,these test methods had different characteristics.The NMR method was used to directly and accurately calculate the UWC in the laboratory.However,the cost and complexity of NMR equipment have precluded its use in the field.The UWC can be effectively estimated by the MIP test,but the estimation accuracy is influenced by the ice crystallization process and the pore size distribution.The P-wave velocity has been demonstrated to be a straightforward and practical empirical parameter and was utilized to estimate the UWC based on the mixture theory.This method may be more suitable in the field.All methods confirmed the existence of a hysteresis phenomenon in the freezing-thawing process.The average hysteresis coefficient was approximately 0.538,thus validating the GibbseThomson equation.This study not only presents alternative methodologies for estimating the UWC of saturated sandstones but also contribute to our understanding of the freezing-thawing process of pore water.

Brain metabolic profile assessed by magnetic resonance spectroscopy in children with Down syndrome:Relation to intelligence quotient

BACKGROUND Down syndrome(DS)is one of the most common causes of intellectual disability.Children with DS have varying intelligence quotient(IQ)that can predict their learning abilities.AIM To assess the brain metabolic profiles of children with DS and compare them to standard controls,using magnetic resonance spectroscopy(MRS)and correlating the results with IQ.METHODS This case-control study included 40 children with DS aged 6-15 years and 40 age and sex-matched healthy children as controls.MRS was used to evaluate ratios of choline/creatine(Cho/Cr),N-acetyl aspartic acid/creatine(NAA/Cr),and myoinositol/creatine(MI/Cr(in the frontal,temporal,and occipital lobes and basal ganglia and compared to controls and correlated with IQ.RESULTS Children with DS showed significant reductions in NAA/Cr and MI/Cr and a non-significant reduction in Cho/Cr in frontal lobes compared to controls.Additionally,we observed significant decreases in NAA/Cr,MI/Cr,and Cho/Cr in the temporal and occipital lobes and basal ganglia in children with DS compared to controls.Furthermore,there was a significant correlation between IQ and metabolic ratios in the brains of children with DS.CONCLUSION Brain metabolic profile could be a good predictor of IQ in children with DS.

Crystallochemical Characterizations, Raman Spectroscopy and Studies Nuclear Magnetic Resonance (NMR) of Cu₂Zn(Sn, Si)S₄Compounds for Photovoltaic Applications

In this study, Si-doped Cu2ZnSnS4 compounds (Cu2ZnSn1-xSixS4, 0 ≤ x ≤ 1) were prepared by solid state reaction method for use of materials for photovoltaic cells. The structural and spectroscopic properties of the as-prepared compounds were studied by X-ray diffraction (XRD), 119Sn, 29Si and 65Cu Magic Angle Spinning nuclear magnetic resonance (MAS NMR) and Raman spectroscopy. The Si-substitution in the Sn-site induces three different types of XRD patterns which depend largely on the Si content in the compound. For 0 ≤ x ≤ 0.5, XRD analysis reveals the presence of a pure tetragonal phase of solid solution with I-42m as a space group. Mixed tetragonal and orthorhombic phases were observed for 0.5 < x < 0.8, followed by a pure orthorhombic structure with a space group Pmn21 at high content of Si (x ≥ 0.8). 119Sn MAS NMR spectra show the presence of Sn/Si disorder as a function of the Si content. The 65Cu MAS NMR spectra of the quadratic solid solution confirm the presence of the two copper sites (Cu-2a and Cu-2c) at 780 ppm while in the case of the orthorhombic solid solution samples, a very broad band is observed. The optical properties were investigated of all compounds by UV-Vis diffuse reflectance and the obtained optical band gap values (1.31 to 2.43 eV) confirm a semiconductor character.

qNMR法测定片剂苯磺酸氨氯地平的含量

本文利用定量核磁共振波谱法(qNMR)建立了测定片剂苯磺酸氨氯地平含量的分析方法。片剂样品经研磨称量后,加入氘代甲醇为溶剂、1,3,5-三甲氧基苯作为内标物进行混合。混合物经涡旋、超声和离心后取上清液转移入核磁管,对样品采集核磁共振氢谱(1H-NMR)。氢谱中以苯磺酸氨氯地平位于δ5.41的谱峰为检测定量峰,1,3,5-三甲氧基苯位于δ 6.07的谱峰为内标定量峰建立绝对定量方法。1H-NMR实验参数为:90度单脉冲序列,脉冲延迟时间30 s,扫描次数32次,采样温度308 K。实验结果显示苯磺酸氨氯地平与内标物的摩尔比在0.42~8.38的范围内具有良好的线性关系(R2=0.9973),精密度和稳定性试验的相对标准偏差(RSD)分别为0.45%(n=7)和0.44%。对于片剂样品,整个方法(包括目标组份的提取和定量核磁检测)重复性试验RSD为1.69%(n=6);三个不同浓度的加标回收率分别为103.86%、101.20%和99.69%。应用本方法对8个市售品牌的苯磺酸氨氯地平片剂进行了含量测定,结果显示建立的qNMR方法准确度高,重复性好,简便快捷,为片剂药品绝对含量的测定提供了新方法。

Liver fat content determined by magnetic resonance imaging and spectroscopy

Hepatic steatosis as the most prevalent liver disorder can either be related to alcoholic liver disease (ALD) or non-alcoholic fatty liver disease (NAFLD). In both conditions, hepatocytes excessively accumulate fatcontaining vacuoles within their cytoplasm, which is the key histological feature. In contrast to ALD, NAFLD is commonly associated with metabolic syndrome, obesity and insulin resistance. To determine increased liver fat content, liver biopsy is currently considered the gold standard. Besides the invasive technique, various other non-invasive techniques have been developed, such as ultrasound, computed tomography (CT), magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) based methods. Among these techniques, ultrasound and CT provide only qualitative information about hepatic steatosis, whereas MRS-or MRI-based methods are able to determine even small amounts of fat accurately. These non-invasive magnetic resonance techniques have already proven their great potential, especially in longitudinal and cross-sectional studies regarding various metabolic conditions and medical treatment regimens. In this review, the most common, non-invasive MRS/MRI techniques for assessment of intrahepatic lipid content are described with their inherent advantages and limitations.

Comparison of magnetic resonance spectroscopy, proton density fat fraction and histological analysis in the quantification of liver steatosis in children and adolescents

AIM To establish a threshold value for liver fat content between healthy children and those with nonalcoholic fatty liver disease(NAFLD) by using magnetic resonance imaging(MRI), with liver biopsy serving as a reference standard. METHODS The study was approved by the local ethics committee, and written informed consent was obtained from all participants and their legal guardians before the study began. Twenty-seven children with NAFLD underwent liver biopsy to assess the presence of nonalcoholic steatohepatitis. The assessment of liver fat fraction was performed using MRI, with a high field magnet and 2D gradient-echo and multiple-echo T1-weighted sequence with low flip angle and single-voxel pointresolved 1H MR-Spectroscopy(1H-MRS), corrected for T1 and T2* decays. Receiver operating characteristic curve analysis was used to determine the best cutoff value. Lin coefficient test was used to evaluate thecorrelation between histology, MRS and MRI-PDFF. A Mann-Whitney U-test and multivariate analysis were performed to analyze the continuous variables. RESULTS According to MRS, the threshold value between healthy children and those with NAFLD is 6%; using MRI-PDFF, a cut-off value of 3.5% is suggested. The Lin analysis revealed a good fit between the histology and MRS as well as MRI-PDFF.CONCLUSION MRS is an accurate and precise method for detecting NAFLD in children.

IN VIVO ~1 H MAGNETIC RESONANCE SPECTROSCOPY IN EVALUATION OF HEPATOCELLULAR CARCINOMA AND ITS EARLY RESPONSE TO TRANSCATHETER ARTERIAL CHEMOEMBOLIZATION

Objective To investigate the value of in vivo proton magnetic resonance spectroscopy （MRS） in the assessment of hepatocelhilar carcinoma （HCC） and monitor its metabolic change shortly after transcatheter arterial chemoembolization （TACE）. Mothoda In this prospective study, 28 consecutive patients with large HCC （ ≥3 cm in diameter） confirmed by fine needle aspiration biopsy were recruited. The ^1H MRS of all hepatic lesions and some uninvolved liver parenchyma were performed with 1.5T whole body MR scanner. Among them, 15 cases were evaluated again about one week after TACE. The main metabolites such as choline and lipid before and after interventional therapy were measured to assess the early response of the tumor. The technical success rate of IH MRS in liver was high （33/41, 80% ）, closely related to breath motion, location of lesion, and size of voxeL In spectra, the choline compound peak of HCC elevated compared with uninvolved liver parenchyma. After TACE, both the amplitude and the area of choline resonance peak significantly descended （ choline-to-lipid ratios from 0.352±0. 080 to 0. 167±0. 030, P = 0. 026; from 0. 205±0. 060 to 0. 070±0. 020, P = 0. 042, respectively ） ; yet lipid resonance peak ascended. Conclusions In vivo tH MRS is technically feasible for the evaluation of large focal hepatic lesions, however, the reproducibility and stability are not as good as routine MR scan. IH MRS can monitor the early stage metabolic changes of HCC after TACE but limitation like quantification still exists.

3.0T 1H magnetic resonance spectroscopy for assessment ofsteatosis in patients with chronic hepatitis C

AIM To investigate the utility of 1H magneticresonance spectroscopy （1H MRS） as a noninvasivetest for steatosis in patients infected with hepatitis Cvirus.METHODS： Ninety patients with chronic hepatitisC and pathology data underwent 3.0T 1H MRS, andthe results of MRS and pathological analysis werecompared.RESULTS： This group of patients included 26 peoplewith mild fatty liver （28.89%）, 16 people withmoderate fatty liver （17.78%）, 18 people with severefatty liver （20.0%）, and 30 people without fatty liver（33.33%）. The water peak was near 4.7 parts permillion （ppm）, and the lipid peak was near 1.3 ppm.Analysis of variance revealed that differences in thelipid peak, the area under the lipid peak, ratio of thelipid peak to the water peak, and ratio of the areaunder the lipid peak to the area under the waterpeak were statistically significant among the groups.Specifically, as the severity of fatty liver increased, thevalue of each index increased correspondingly. In thepairwise comparisons, the mean lipid peak, area underthe lipid peak, ratio of the lipid peak to the waterpeak, and ratio of the area under the lipid peak to thearea under the water peak were significantly differentbetween the no fatty liver and moderate fatty liver groups, whereas no differences were noted betweenthe severe fatty liver group and the mild or moderatefatty liver group. Area under the ROC curve （AUC） ofarea ratio in lipid and water and ratio in lipid and waterin the no fatty liver group to mild fatty liver group, mildfatty liver group to moderate fatty liver group, andmoderate fatty liver disease group to severe fatty livergroup, were 0.705, 0.900, and 0.975, respectively.CONCLUSION： 1H MRS is a noninvasive techniquethat can be used to provide information on the effectof liver steatosis on hepatic metabolic processes. Thisstudy indicates that the 1H MRS can be used as anindicator of steatosis in patients with chronic hepatitis C.

In vivo magnetic resonance spectroscopy of liver tumors and metastases

Primary liver cancer is the fifth most common malignancy in men and the eighth in women worldwide. The liver is also the second most common site for metastatic spread of cancer. To assist in the diagnosis of these liver lesions non-invasive advanced imaging techniques are desirable. Magnetic resonance (MR) is commonly used to identify anatomical lesions, but it is a very versatile technique and also can provide specific information on tumor pathophysiology and metabolism, in particular with the application of MR spectroscopy (MRS). This may include data on the type, grade and stage of tumors, and thus assist in further management of the disease. The purpose of this review is to summarize and discuss the available literature on proton, phosphorus and carbon-13-MRS as performed on primary liver tumors and metastases, with human applications as the main perspective. Upcoming MRSapproaches with potential applications to liver tumors are also included. Since knowledge of some technical background is indispensable to understand the results, a basic introduction of MRS and some technical issues of MRS as applied to tumors and metastases in the liver are described as well. In vivo MR spectroscopy of tumors in a metabolically active organ such as the liver has been demonstrated to provide important information on tumor metabolism, but it also is challenging as compared to applications on some other tissues, in particular in humans, mostly because of its abdominal location where movement may be a disturbing factor.

Magnetic resonance spectroscopy to study hepatic metabolism in diffuse liver diseases, diabetes and cancer

This review provides an overview of the current state of the art of magnetic resonance spectroscopy (MRS) in in vivo investigations of diffuse liver disease. So far, MRS of the human liver in vivo has mainly been used as a research tool rather than a clinical tool. The liver is particularly suitable for static and dynamic metabolic studies due to its high metabolic activity. Furthermore, its relatively superfi cial position allows excellent MRS localization, while its large volume allows detection of signals with relatively low intensity. This review describes the application of MRS to study the metabolic consequences of different conditions including diffuse and chronic liver diseases, congenital diseases, diabetes, and the presence of a distant malignancy on hepatic metabolism. In addition, future prospects of MRS are discussed. It is anticipated that future technical developments such as clinical MRS magnets with higher fi eld strength (3 T) and improved delineation of multicomponent signals such as phosphomonoester and phosphodiester using proton decoupling, especially if combined with price reductions for stable isotope tracers, will lead to intensifi ed research into metabolic syndrome, cardiovascular disease, hepato-biliary diseases, as well as non-metastatic liver metabolism in patients with a distant malignant tumor.

Early Biomarkers in 1H Nuclear Magnetic Resonance Spectroscopy of Striatal Pathological Mechanisms after Acute Carbon Monoxide Poisoning in Rats

Objective In vivo Proton Magnetic Resonance Spectroscopy （1H-MRS） can be used to evaluate the levels of specific neurochemical biomarkers of pathological mechanisms in the brain. Methods We conducted T2-Weighted Magnetic Resonance Imaging （MRI） and 1H-MRS with a 3.0-Tesla animal MRI system to investigate the early microstructural and metabolic profiles in vivo in the striatum of rats following carbon monoxide （CO） poisoning. Results Compared to baseline, we found significant cortical surface deformation, cerebral edema changes, which were indicated by the unclear gray/white matter border, and lateral ventricular volume changes in the brain. A significant reduction in the metabolite to total creatine （Cr） ratios of N-acetylaspartate （NAA） was observed as early as 1 h after the last CO administration, while the lactate （Lac） levels increased marginally. Both the Lac/Cr and NAA/Cr ratios leveled off at 6 h and showed no subsequent significant changes. In addition, compared to the control, the choline （Cho）/Cr ratio was slightly reduced in the early stages and significantly increased after 6 h. In addition, a pathological examination revealed mild cerebral edema on cessation of the insult and more severe cerebral injury after additional CO poisoning. Conclusion The present study demonstrated that 1H-MRS of the brain identified early metabolic changes after CO poisoning. Notably, the relationship between the increased Cho/Cr ratio in the striatum and delayed neuropsychologic sequelae requires further research.

Current and future applications of magnetic resonance imaging and spectroscopy of the brain in hepatic encepha-lopathy

Hepatic encephalopathy （HE） is a common neuropsychiatric abnormality, which complicates the course of patients with liver disease and results from hepatocellular failure and/or portosystemic shunting. The manifestations of HE are widely variable and involve a spectrum from mild subclinical disturbance to deep coma. Research interest has focused on the role of circulating gut-derived toxins, particularly ammonia, the development of brain swelling and changes in cerebral neurotransmitter systems that lead to global CNS depression and disordered function. Until recently the direct investigation of cerebral function has been difficult in man. However, new magnetic resonance imaging （MRI） techniques provide a non-invasive means of assessment of changes in brain volume （coregistered MRI） and impaired brain function （fMRI）, while proton magnetic resonance spectroscopy （^1H MRS） detects changes in brain biochemistry, including direct measurement of cerebral osmolytes, such as myoinositol, glutamate and glutamine which govern processes intrinsic to cellular homeostasis, including the accumulation of intracellular water. The concentrations of these intracellular osmolytes alter with hyperammonaemia. MRS-detected metabolite abnormalities correlate with the severity of neuropsychiatric impairment and since MR spectra return towards normal after treatment, the technique may be of use in objective patient monitoring and in assessing the effectiveness of various treatment regimens.

Current and future applications of in vitro magnetic resonance spectroscopy in hepatobiliary disease

Nuclear magnetic resonance spectroscopy allows the study of cellular biochemistry and metabolism, both in the whole body in vivo and at higher magnetic field strengths in vitro. Since the technique is non-invasive and non-selective, magnetic resonance spectroscopy methodologies have been widely applied in biochemistry and medicine. In vitro magnetic resonance spectroscopy studies of cells, body fluids and tissues have been used in medical biochemistry to investigate pathophysiologi- cal processes and more recently, the technique has been used by physicians to determine disease abnormalities in vivo. This highlighted topic illustrates the potential of in vitro magnetic resonance spectroscopy in studying the hepatobiliary system. The role of in vitro proton and phosphorus magnetic resonance spectroscopy in the study of malignant and non-malignant liver disease and bile composition studies are discussed, particularly with reference to correlative in vivo whole-body magnetic resonance spectroscopy applications. In summary, magnetic resonance spectroscopy techniques can provide non-invasive biochemical information on disease severity and pointers to underlying pathophysiological processes. Magnetic resonance spectroscopy holds potential promise as a screening tool for disease biomarkers, as well as assessing therapeutic response.

Urinary nuclear magnetic resonance spectroscopy of a Bangladeshi cohort with hepatitis-B hepatocellular carcinoma: A biomarker corroboration study

AIM: To establish if a distinct urinary metabolic profile could be identified in Bangladeshi hepatitis-B hepatocellular carcinoma (HCC) patients compared to cirrhosis patients and controls.METHODS: Urine samples from 42 Bangladeshi patients with HCC (39 patients with hepatitis-B HCC), 47 with cirrhosis on a background of hepatitis B, 46 with chronic hepatitis B, and seven ethnically-matched healthy controls were analyzed using nuclear magnetic resonance (NMR) spectroscopy. A full dietary and medication history was recorded for each subject. The urinary NMR data were analyzed using principal component analysis (PCA) and orthogonal partial least squared discriminant analysis (OPLS-DA) techniques. Differences in relative signal levels of the most discriminatory metabolites identified by PCA and OPLS-DA were compared between subject groups using an independent samples Kruskal-Wallis one-way analysis of variance (ANOVA) test with all pairwise multiple comparisons. Within the patient subgroups, the Mann-Whitney U test was used to compare metabolite levels depending on hepatitis B e-antigen (HBeAg) status and treatment with anti-viral therapy. A Benjamini-Hochberg adjustment was applied to acquire the level of significance for multiple testing, with a declared level of statistical significance of P &#x0003c; 0.05.RESULTS: There were significant differences in age (P &#x0003c; 0.001), weight (P &#x0003c; 0.001), and body mass index (P &#x0003c; 0.001) across the four clinical subgroups. Serum alanine aminotransferase (ALT) was significantly higher in the HCC group compared to controls (P &#x0003c; 0.001); serum &#x003b1;-fetoprotein was generally markedly elevated in HCC compared to controls; and serum creatinine levels were significantly reduced in the HCC group compared to the cirrhosis group (P = 0.004). A three-factor PCA scores plot showed clustering of the urinary NMR spectra from the four subgroups. Metabolites that contributed to the discrimination between the subgroups included acetate, creatine, creatinine, dimethyamine (DMA), formate, glycine, hippurate, and trimethylamine-N-oxide (TMAO). A comparison of relative metabolite levels confirmed that carnitine was significantly increased in HCC; and creatinine, hippurate, and TMAO were significantly reduced in HCC compared to the other subgroups. HBeAg negative patients showed a significant increase in creatinine (P = 0.001) compared to HBeAg positive patients in the chronic hepatitis B subgroup, whilst HBeAg negative patients showed a significant decrease in DMA (P = 0.004) in the cirrhosis subgroup compared to HBeAg positive patients. There were no differences in metabolite levels in HCC patients who did or did not receive antiviral treatment.CONCLUSION: Urinary NMR changes in Bangladeshi HCC were identified, corroborating previous findings from Egypt and West Africa. These findings could form the basis for the development of a cost-effective HCC dipstick screening test.

3.0 T proton magnetic resonance spectroscopy of the liver: Quantification of choline

AIM: To investigate the normal hepatic magnetic resonance spectroscopy findings choline/lipid2 (Cho/Lip2) associated with age and body mass index (BMI).METHODS: A total of 58 single-voxel proton spectra of the liver were acquired at 3.0 T using the eightchannel phased array abdominal coil as the receiver coil. Consecutive stacks of breath-hold spectra were acquired using the point resolved spectroscopy technique at a short echo time of 30 ms and a repetition time of 1500 ms. The spectra were processed with the SAGE software package. Areas and heights for metabolite resonance were obtained. Student's t test for unpaired data was used for comparisons of shimming, Cho/Lip2, and lipid content. RESULTS: There were significant negative correlations between the Cho/Lip2 peak height ratios and BMI (r=-0.615) and age (r=-0.398) (all P<0.01). Compared with the high-BMI group, the low-BMI group was younger (39.1±13.0 years vs 47.6±8.5 years, t=-2.954,P=0.005); had better water suppression (93.4%±1.4% vs 85.6%±11.6%, t=2.741, P=0.014); had higher Cho/Lip2 peak heights ratio (0.2±0.14 vs 0.05±0.04,t=6.033,P<0.000); and had lower lipid content (0.03±0.08 vs 0.29±0.31, t=-3.309, P=0.004). Compared with the older group, the younger group had better shimming effects (17.1±3.6 Hz vs 22.0±6.8 Hz, t=-2.919, P=0.008); higher Cho/Lip2 peak heights ratios (0.03±0.05vs 0.09±0.12,t=2.4, P=0.020); and lower lipid content (0.05±0.11 vs 0.23±0.32,t=-2.337,P=0.031). Compared with the lowcholine peak group, the high-choline peak group had lower lipid content (0.005±0.002 vs 0.13±0.23, t=-3.796,P<0.000); lower BMI (19.6±2.4vs 23.9±3.0, t=-4.410, P<0.000); and younger age (34.7±10.0 years vs 43.2±12.5 years, t=-2.088, P=0.041). CONCLUSION: Lipid accumulation could result from the increased fat in the body depending on age and BMI. Lipid can mask the resonance signal of choline.

Quantification of choline concentration following liver cell apoptosis using ~1H magnetic resonance spectroscopy

AIM: To evaluate the feasibility of quantifying liver choline concentrations in both normal and apoptotic rabbit livers in vivo, using 1H magnetic resonance spectroscopy (1H-MRS). METHODS: 1H-MRS was performed in 18 rabbits using a 1.5T GE MR system with an eight-channel head/neck receiving coil. Fifteen rabbits were injected with sodium selenite at a dose of 10 μmol/kg to induce the liver cell apoptosis. Point-resolved spectroscopy sequencelocalized spectra were obtained from 10 livers once before and once 24 h after sodium selenite injection in vivo. T1 and T2 relaxation time of water and choline was measured separately in the livers of three healthy rabbits and three selenite-treated rabbits. Hematoxylin and eosin and dUTP-biotin nick end labeling (TUNEL) staining was used to detect and confirm apoptosis. Choline peak areas were measured relative to unsuppressed water using LCModel. Relaxation attenuation was corrected using the average of T1 and T2 relaxation time. The choline concentration was quantified using a formula, which was tested by a phantom with a known concentration. RESULTS: Apoptosis of hepatic cells was confirmed by TUNEL assay. In phantom experiment, the choline concentration (3.01 mmol/L), measured by 1H-MRS, was in good agreement with the actual concentration (3 mmol/L). The average T1 and T2 relaxation time of choline was 612 ± 15 ms and 74 ± 4 ms in the control group and 670 ± 27 ms and 78 ± 5 ms in apoptotic livers in vivo, respectively. Choline was quantified in 10 rabbits, once before and once after the injection with sodium selenite. The choline concentration decreased from 14.5 ± 7.57 mmol/L before sodium selenite injection to 10.8 ± 6.58 mmol/L (mean ± SD, n = 10) after treatment (Z = -2.395, P < 0.05, two-sample paired Wilcoxon test). CONCLUSION: 1H-MRS can be used to quantify liver choline in vivo using unsuppressed water as an internal reference. Decreased liver choline concentrations are found in sodium selenite-treated rabbits undergoing liver cell apoptosis.

基于LF-NMR研究双孢菇远红外辅助热泵干燥过程中水分迁移规律及品质变化

为研究双孢菇远红外辅助热泵干燥过程中水分分布规律及品质变化,采用低场核磁共振及成像技术分别对干燥过程的双孢菇进行弛豫特性及质子密度成像分析,并研究干燥前、后双孢菇微观结构和品质的变化。结果表明:在热泵温度分别为45,55,65℃时,双孢菇到达干燥终点的时间分别为510,420,390 min。双孢菇的T2反演谱有3个不同的弛豫峰:T21(3~23 ms)、T22(25~155 ms)和T23(155~1084 ms),分别代表双孢菇中的结合水、不易流动水和自由水。干燥初期,T23左迁幅度很大,干燥后期,左迁幅度变小,随着干燥时间的延长,自由水的流动性降低。干燥结束时,T23对应的弛豫峰下降约99.8%,只剩下部分T21和T22对应的峰,说明自由水几乎被完全去除,双孢菇内仅剩结合水和少量不易流动水。低场核磁共振图像显示,65℃条件下,干燥360 min,水分基本被脱除,而55℃和45℃处理组分别在干燥390 min和450 min才基本脱除。双孢菇外侧的水分先被脱除,内部的水分向外迁移,并且温度越高,内部水分迁移速率越快。另外,65℃条件下的双孢菇的BI值分别比45℃和55℃条件下的BI低30.55%和22.69%,说明65℃更能维持双孢菇原有的色泽。65℃条件下干燥的双孢菇的抗坏血酸、总酚、总黄酮含量分别比干燥前下降84.62%,55.80%和36.78%,与45℃和55℃相比,65℃下双孢菇营养成分的损失最小。本研究表明低场核磁共振及成像技术为双孢菇干燥过程中水分的变化提供了直观的参考依据,也可为双孢菇的远红外辅助热泵干燥工艺优化干燥参数、提高产品质量提供理论参考。