Science.gov

Sample records for 1h t1 values

  1. Diagnostic value of 3.0T (1)H MRS with choline-containing compounds ratio (∆CCC) in primary malignant hepatic tumors.

    PubMed

    Zhang, Li; Zhao, Xinming; Ouyang, Han; Wang, Shuang; Zhou, Chunwu

    2016-08-22

    The purpose of this study was to investigate the diagnostic value of 3.0-T (1)H magnetic resonance spectroscopy ((1)H MRS) in primary malignant hepatic tumors and to compare the effects of (1)H MRS on the diagnostic accuracy of liver-occupying lesions between junior and experienced radiologists. This study included 50 healthy volunteers and 40 consecutive patients (50 lesions). Informed consent was obtained from each subject. Images were obtained on clinical whole-body 3.0-T MR system. Point -Resolved Spectroscopy was used to obtain the spectroscopy image. All conventional images were reviewed blindly by junior radiologist and experienced radiologist, respectively. The choline-containing compounds peak area (CCC-A) was measured with SAGE software, and the choline-containing compound ratio (∆CCC) was calculated. The efficacy of CCC-A and ∆CCC in the diagnosis of primary malignant hepatic tumors was determined by plotting receiver operating characteristic (ROC) curves. We also compared the effects of MRS on the diagnostic accuracy of liver-occupying lesions with junior and experienced radiologist. A significant increase in mean CCC-A was observed in malignant tumors compared with benign tumors. The ROC curve showed ∆CCC had a high discriminatory ability in diagnosing primary malignant hepatic tumors with a sensitivity and specificity of 94.3 and 93.3 %, respectively. The ∆CCC area under the curve (AUC) was 0.97 that was larger than that of both junior and experienced radiologist, while the significantly statistical difference was only obtained between ∆CCC and junior radiologist (P = 0.01). (1)H MRS with ∆CCC demonstrates good efficacy in diagnosing primary malignant hepatic tumors. The technique improves the accuracy of diagnosing liver-occupying lesions, particularly for junior radiologists.

  2. 1H metabolite relaxation times at 3.0 tesla: Measurements of T1 and T2 values in normal brain and determination of regional differences in transverse relaxation.

    PubMed

    Träber, Frank; Block, Wolfgang; Lamerichs, Rolf; Gieseke, Jürgen; Schild, Hans H

    2004-05-01

    To measure 1H relaxation times of cerebral metabolites at 3 T and to investigate regional variations within the brain. Investigations were performed on a 3.0-T clinical whole-body magnetic resonance (MR) system. T2 relaxation times of N-acetyl aspartate (NAA), total creatine (tCr), and choline compounds (Cho) were measured in six brain regions of 42 healthy subjects. T1 relaxation times of these metabolites and of myo-inositol (Ins) were determined in occipital white matter (WM), the frontal lobe, and the motor cortex of 10 subjects. T2 values of all metabolites were markedly reduced with respect to 1.5 T in all investigated regions. T2 of NAA was significantly (P < 0.001) shorter in the motor cortex (247 +/- 13 msec) than in occipital WM (301 +/- 18 msec). T2 of the tCr methyl resonance showed a corresponding yet less pronounced decrease (162 +/- 16 msec vs. 178 +/- 9 msec, P = 0.021). Even lower T2 values for all metabolites were measured in the basal ganglia. Metabolite T1 relaxation times at 3.0 T were not significantly different from the values at 1.5 T. Transverse relaxation times of the investigated cerebral metabolites exhibit an inverse proportionality to magnetic field strength, and especially T2 of NAA shows distinct regional variations at 3 T. These can be attributed to differences in relative WM/gray matter (GM) contents and to local paramagnetism. Copyright 2004 Wiley-Liss, Inc.

  3. Review of /sup 1/H nuclear magnetic resonance relaxation in pathology: are T1 and T2 diagnostic

    SciTech Connect

    Bottomley, P.A.; Hardy, C.J.; Argersinger, R.E.; Allen-Moore, G.

    1987-01-01

    The longitudinal (T1) and transverse (T2) proton (1H) nuclear magnetic resonance (NMR) relaxation times of pathological human and animal tissues in the frequency range 1-100 MHz are archived, reviewed, and analyzed as a function of tissue of origin, NMR frequency, temperature, species, and in vivo versus in vitro status. T1 data from specific disease states of the bone, brain, breast, kidney, liver, muscle, pancreas, and spleen can be characterized by simple dispersions of the form T1 = AvB in the range 1-100 MHz with A and B empirically determined pathology-dependent constants. Pathological tissue T2 values are essentially independent of NMR frequency. Raw relaxation data, best-fit T1 parameters A and B, and the mean T2 values, are tabulated along with standard deviations and sample size to establish the normal range of pathological tissue relaxation times applicable to NMR imaging or in vitro NMR examination. Statistical analysis of relaxation data, assumed independent, reveals that most tumor and edematous tissue T1 values and some breast, liver, and muscle tumor T2 values are significantly elevated relative to normal, but do not differ significantly from other tumors and pathologies. Statistically significant abnormalities in the T1 values of some brain, breast, and lung tumors, and most pathological tissue T2 values could not, however, be demonstrated in the presence of large statistical errors. Both T1 and T2 in uninvolved tissue from tumor-bearing animals or organs do not demonstrate statistically significant differences from normal when considered as a group, suggesting no appreciable systemic effects associated with the presence of tumors compared to the statistical uncertainty.261 references. (Abstract Truncated)

  4. Analysis of amorphous solid dispersions using 2D solid-state NMR and (1)H T(1) relaxation measurements.

    PubMed

    Pham, Tran N; Watson, Simon A; Edwards, Andrew J; Chavda, Manisha; Clawson, Jacalyn S; Strohmeier, Mark; Vogt, Frederick G

    2010-10-04

    Solid-state NMR (SSNMR) can provide detailed structural information about amorphous solid dispersions of pharmaceutical small molecules. In this study, the ability of SSNMR experiments based on dipolar correlation, spin diffusion, and relaxation measurements to characterize the structure of solid dispersions is explored. Observation of spin diffusion effects using the 2D (1)H-(13)C cross-polarization heteronuclear correlation (CP-HETCOR) experiment is shown to be a useful probe of association between the amorphous drug and polymer that is capable of directly proving glass solution formation. Dispersions of acetaminophen and indomethacin in different polymers are examined using this approach, as well as (1)H double-quantum correlation experiments to probe additional structural features. (1)H-(19)F CP-HETCOR serves a similar role for fluorinated drug molecules such as diflunisal in dispersions, providing a rapid means to prove the formation of a glass solution. Phase separation is detected using (13)C, (19)F, and (23)Na-detected (1)H T(1) experiments in crystalline and amorphous solid dispersions that contain small domains. (1)H T(1) measurements of amorphous nanosuspensions of trehalose and dextran illustrate the ability of SSNMR to detect domain size effects in dispersions that are not glass solutions via spin diffusion effects. Two previously unreported amorphous solid dispersions involving up to three components and containing voriconazole and telithromycin are analyzed using these experiments to demonstrate the general applicability of the approach.

  5. Measurement of T1/T2 relaxation times in overlapped regions from homodecoupled 1H singlet signals

    NASA Astrophysics Data System (ADS)

    Castañar, Laura; Nolis, Pau; Virgili, Albert; Parella, Teodor

    2014-07-01

    The implementation of the HOmodecoupled Band-Selective (HOBS) technique in the conventional Inversion-Recovery and CPMG-based PROJECT experiments is described. The achievement of fully homodecoupled signals allows the distinction of overlapped 1H resonances with small chemical shift differences. It is shown that the corresponding T1 and T2 relaxation times can be individually measured from the resulting singlet lines using conventional exponential curve-fitting methods.

  6. Prefrontal NAA and Glx Levels in Different Stages of Psychotic Disorders: a 3T 1H-MRS Study

    PubMed Central

    Liemburg, Edith; Sibeijn-Kuiper, Anita; Bais, Leonie; Pijnenborg, Gerdina; Knegtering, Henderikus; van der Velde, Jorien; Opmeer, Esther; de Vos, Annerieke; Dlabac-De Lange, Jozarni; Wunderink, Lex; Aleman, André

    2016-01-01

    H-Magnetic Resonance Spectroscopy (1H-MRS) can offer insights in various neuropathologies by measuring metabolite levels in the brain. In the current study we investigated the levels of glutamate + glutamine (Glx, neurotransmitter and precursor) and N-Acetyl Aspartate + glutamic acid (NAA + NAAG; neuronal viability) in the prefrontal cortex of patients with a psychotic disorder and people at Ultra High Risk (UHR) for psychosis. A 1H-MRS spectrum was acquired in 31 patients with a recent onset psychotic disorder and 60 with a chronic state, 16 UHR patients and 36 healthy controls. Absolute metabolite levels were calculated using LCModel with a reference water peak. Groups were compared while taking into account age and partial volume effects. Moreover, we investigated associations with positive and negative symptoms, duration of illness, and antipsychotic treatment in patients. The most notable finding is that chronicity of schizophrenia was related to decreased levels of Glx and NAA. On the other hand, although on an exploratory note, UHR showed increased levels of prefrontal Glx and NAA levels with increasing age. Our results may indicate an initial Glx and NAA increase and subsequent decrease during illness progression that may be related to the neurotoxic effects of glutamate. PMID:26903078

  7. Prefrontal NAA and Glx Levels in Different Stages of Psychotic Disorders: a 3T 1H-MRS Study.

    PubMed

    Liemburg, Edith; Sibeijn-Kuiper, Anita; Bais, Leonie; Pijnenborg, Gerdina; Knegtering, Henderikus; van der Velde, Jorien; Opmeer, Esther; de Vos, Annerieke; Dlabac-De Lange, Jozarni; Wunderink, Lex; Aleman, André

    2016-02-23

    H-Magnetic Resonance Spectroscopy ((1)H-MRS) can offer insights in various neuropathologies by measuring metabolite levels in the brain. In the current study we investigated the levels of glutamate + glutamine (Glx, neurotransmitter and precursor) and N-Acetyl Aspartate + glutamic acid (NAA + NAAG; neuronal viability) in the prefrontal cortex of patients with a psychotic disorder and people at Ultra High Risk (UHR) for psychosis. A (1)H-MRS spectrum was acquired in 31 patients with a recent onset psychotic disorder and 60 with a chronic state, 16 UHR patients and 36 healthy controls. Absolute metabolite levels were calculated using LCModel with a reference water peak. Groups were compared while taking into account age and partial volume effects. Moreover, we investigated associations with positive and negative symptoms, duration of illness, and antipsychotic treatment in patients. The most notable finding is that chronicity of schizophrenia was related to decreased levels of Glx and NAA. On the other hand, although on an exploratory note, UHR showed increased levels of prefrontal Glx and NAA levels with increasing age. Our results may indicate an initial Glx and NAA increase and subsequent decrease during illness progression that may be related to the neurotoxic effects of glutamate.

  8. The use of a selective saturation pulse to suppress t1 noise in two-dimensional 1H fast magic angle spinning solid-state NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Robertson, Aiden J.; Pandey, Manoj Kumar; Marsh, Andrew; Nishiyama, Yusuke; Brown, Steven P.

    2015-11-01

    A selective saturation pulse at fast magic angle spinning (MAS) frequencies (60+ kHz) suppresses t1 noise in the indirect dimension of two-dimensional 1H MAS NMR spectra. The method is applied to a synthetic nucleoside with an intense methyl 1H signal due to triisopropylsilyl (TIPS) protecting groups. Enhanced performance in terms of suppressing the methyl signal while minimising the loss of signal intensity of nearby resonances of interest relies on reducing spin diffusion - this is quantified by comparing two-dimensional 1H NOESY-like spin diffusion spectra recorded at 30-70 kHz MAS. For a saturation pulse centred at the methyl resonance, the effect of changing the nutation frequency at different MAS frequencies as well as the effect of changing the pulse duration is investigated. By applying a pulse of duration 30 ms and nutation frequency 725 Hz at 70 kHz MAS, a good compromise of significant suppression of the methyl resonance combined with the signal intensity of resonances greater than 5 ppm away from the methyl resonance being largely unaffected is achieved. The effectiveness of using a selective saturation pulse is demonstrated for both homonuclear 1H-1H double quantum (DQ)/single quantum (SQ) MAS and 14N-1H heteronuclear multiple quantum coherence (HMQC) two-dimensional solid-state NMR experiments.

  9. The use of a selective saturation pulse to suppress t1 noise in two-dimensional (1)H fast magic angle spinning solid-state NMR spectroscopy.

    PubMed

    Robertson, Aiden J; Pandey, Manoj Kumar; Marsh, Andrew; Nishiyama, Yusuke; Brown, Steven P

    2015-11-01

    A selective saturation pulse at fast magic angle spinning (MAS) frequencies (60+kHz) suppresses t1 noise in the indirect dimension of two-dimensional (1)H MAS NMR spectra. The method is applied to a synthetic nucleoside with an intense methyl (1)H signal due to triisopropylsilyl (TIPS) protecting groups. Enhanced performance in terms of suppressing the methyl signal while minimising the loss of signal intensity of nearby resonances of interest relies on reducing spin diffusion--this is quantified by comparing two-dimensional (1)H NOESY-like spin diffusion spectra recorded at 30-70 kHz MAS. For a saturation pulse centred at the methyl resonance, the effect of changing the nutation frequency at different MAS frequencies as well as the effect of changing the pulse duration is investigated. By applying a pulse of duration 30 ms and nutation frequency 725 Hz at 70 kHz MAS, a good compromise of significant suppression of the methyl resonance combined with the signal intensity of resonances greater than 5 ppm away from the methyl resonance being largely unaffected is achieved. The effectiveness of using a selective saturation pulse is demonstrated for both homonuclear (1)H-(1)H double quantum (DQ)/single quantum (SQ) MAS and (14)N-(1)H heteronuclear multiple quantum coherence (HMQC) two-dimensional solid-state NMR experiments.

  10. Negative Correlation between Brain Glutathione Level and Negative Symptoms in Schizophrenia: A 3T 1H-MRS Study

    PubMed Central

    Matsuzawa, Daisuke; Obata, Takayuki; Shirayama, Yukihiko; Nonaka, Hiroi; Kanazawa, Yoko; Yoshitome, Eiji; Takanashi, Junichi; Matsuda, Tsuyoshi; Shimizu, Eiji; Ikehira, Hiroo; Iyo, Masaomi; Hashimoto, Kenji

    2008-01-01

    Background Glutathione (GSH), a major intracellular antioxidant, plays a role in NMDA receptor-mediated neurotransmission, which is involved in the pathophysiology of schizophrenia. In the present study, we aimed to investigate whether GSH levels are altered in the posterior medial frontal cortex of schizophrenic patients. Furthermore, we examined correlations between GSH levels and clinical variables in patients. Methods and Findings Twenty schizophrenia patients and 16 age- and gender-matched normal controls were enrolled to examine the levels of GSH in the posterior medial frontal cortex by using 3T SIGNA EXCITE 1H-MRS with the spectral editing technique, MEGA-PRESS. Clinical variables of patients were assessed by the Global Assessment of Functioning (GAF), Scale for the Assessment of Negative Symptoms (SANS), Brief Psychiatric Rating Scale (BPRS), Drug-Induced Extra-Pyramidal Symptoms Scale (DIEPSS), and five cognitive performance tests (Word Fluency Test, Stroop Test, Trail Making Test, Wisconsin Card Sorting Test and Digit Span Distractibility Test). Levels of GSH in the posterior medial frontal cortex of schizophrenic patients were not different from those of normal controls. However, we found a significant negative correlation between GSH levels and the severity of negative symptoms (SANS total score and negative symptom subscore on BPRS) in patients. There were no correlations between brain GSH levels and scores on any cognitive performance test except Trail Making Test part A. Conclusion These results suggest that GSH levels in the posterior medial frontal cortex may be related to negative symptoms in schizophrenic patients. Therefore, agents that increase GSH levels in the brain could be potential therapeutic drugs for negative symptoms in schizophrenia. PMID:18398470

  11. Quantitative Component Analysis of Solid Mixtures by Analyzing Time Domain (1)H and (19)F T1 Saturation Recovery Curves (qSRC).

    PubMed

    Stueber, Dirk; Jehle, Stefan

    2017-07-01

    Prevalent polymorphism and complicated phase behavior of active pharmaceutical ingredients (APIs) often result in remarkable differences in the respective biochemical and physical API properties. Consequently, API form characterization and quantification play a central role in the pharmaceutical industry from early drug development to manufacturing. Here we present a novel and proficient quantification protocol for solid mixtures (qSRC) based on the measurement and mathematical fitting of T1 nuclear magnetic resonance (NMR) saturation recovery curves collected on a bench top time-domain NMR instrument. The saturation recovery curves of the relevant pure components are used as fingerprints. Employing a bench top NMR instrument possesses clear benefits. These instruments exhibit a small footprint, do not present any special requirements on lab space, and required sample handling is simple and fast. The qSRC analysis can easily be conducted in a conventional laboratory setting as well as in an industrial production environment, making it a versatile tool with the potential for widespread application. The accuracy and efficiency of the qSRC method is illustrated using (1)H and (19)F T1 data of selected pharmaceutical model compounds, as well as utilizing (1)H T1 data of an actual binary API anhydrous polymorph system of a Merck & Co., Inc. compound formerly developed as a hepatitis C virus drug. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  12. Contrast-enhanced 3T MR Perfusion of Musculoskeletal Tumours: T1 Value Heterogeneity Assessment and Evaluation of the Influence of T1 Estimation Methods on Quantitative Parameters.

    PubMed

    Gondim Teixeira, Pedro Augusto; Leplat, Christophe; Chen, Bailiang; De Verbizier, Jacques; Beaumont, Marine; Badr, Sammy; Cotten, Anne; Blum, Alain

    2017-06-14

    To evaluate intra-tumour and striated muscle T1 value heterogeneity and the influence of different methods of T1 estimation on the variability of quantitative perfusion parameters. Eighty-two patients with a histologically confirmed musculoskeletal tumour were prospectively included in this study and, with ethics committee approval, underwent contrast-enhanced MR perfusion and T1 mapping. T1 value variations in viable tumour areas and in normal-appearing striated muscle were assessed. In 20 cases, normal muscle perfusion parameters were calculated using three different methods: signal based and gadolinium concentration based on fixed and variable T1 values. Tumour and normal muscle T1 values were significantly different (p = 0.0008). T1 value heterogeneity was higher in tumours than in normal muscle (variation of 19.8% versus 13%). The T1 estimation method had a considerable influence on the variability of perfusion parameters. Fixed T1 values yielded higher coefficients of variation than variable T1 values (mean 109.6 ± 41.8% and 58.3 ± 14.1% respectively). Area under the curve was the least variable parameter (36%). T1 values in musculoskeletal tumours are significantly different and more heterogeneous than normal muscle. Patient-specific T1 estimation is needed for direct inter-patient comparison of perfusion parameters. • T1 value variation in musculoskeletal tumours is considerable. • T1 values in muscle and tumours are significantly different. • Patient-specific T1 estimation is needed for comparison of inter-patient perfusion parameters. • Technical variation is higher in permeability than semiquantitative perfusion parameters.

  13. Increased native T1-values at the interventricular insertion regions in precapillary pulmonary hypertension.

    PubMed

    Spruijt, Onno A; Vissers, Loek; Bogaard, Harm-Jan; Hofman, Mark B M; Vonk-Noordegraaf, Anton; Marcus, J Tim

    2016-03-01

    Cardiac magnetic resonance imaging of the pressure overloaded right ventricle (RV) of precapillary pulmonary hypertension (PH) patients, exhibits late gadolinium enhancement at the interventricular insertion regions, a phenomenon which has been linked to focal fibrosis. Native T1-mapping is an alternative technique to characterize myocardium and has the advantage of not requiring the use of contrast agents. The aim of this study was to characterize the myocardium of idiopathic pulmonary arterial hypertension (IPAH), systemic scleroderma related PH (PAH-Ssc) and chronic thromboembolic PH (CTEPH) patients using native T1-mapping and to see whether native T1-values were related to disease severity. Furthermore, we compared native T1-values between the different precapillary PH categories. Native T1-mapping was performed in 46 IPAH, 14 PAH-SSc and 10 CTEPH patients and 10 control subjects. Native T1-values were assessed using regions of interest at the RV and LV free wall, interventricular septum and interventricular insertion regions. In PH patients, native T1-values of the interventricular insertion regions were significantly higher than the native T1-values of the RV free wall, LV free wall and interventricular septum. Native T1-values at the insertion regions were significantly related to disease severity. Native T1-values were not different between IPAH, PAH-Ssc and CTEPH patients. Native T1-values of the interventricular insertion regions are significantly increased in precapillary PH and are related to disease severity. Native T1-mapping can be developed as an alternative technique for the characterization of the interventricular insertion regions and has the advantage of not requiring the use of contrast agents.

  14. Free-breathing post-contrast three-dimensional T1 mapping: Volumetric assessment of myocardial T1 values.

    PubMed

    Weingärtner, Sebastian; Akçakaya, Mehmet; Roujol, Sébastien; Basha, Tamer; Stehning, Christian; Kissinger, Kraig V; Goddu, Beth; Berg, Sophie; Manning, Warren J; Nezafat, Reza

    2015-01-01

    To develop a three-dimensional (3D) free-breathing myocardial T1 mapping sequence for assessment of left ventricle diffuse fibrosis after contrast administration. In the proposed sequence, multiple 3D inversion recovery images are acquired in an interleaved manner. A mixed prospective/retrospective navigator scheme is used to obtain the 3D Cartesian k-space data with fully sampled center and randomly undersampled outer k-space. The resulting undersampled 3D k-space data are then reconstructed using compressed sensing. Subsequently, T1 maps are generated by voxel-wise curve fitting of the individual interleaved images. In a phantom study, the accuracy of the 3D sequence was evaluated against two-dimensional (2D) modified Look-Locker inversion recovery (MOLLI) and spin-echo sequences. In vivo T1 times of the proposed method were compared with 2D multislice MOLLI T1 mapping. Subsequently, the feasibility of high-resolution 3D T1 mapping with spatial resolution of 1.7 × 1.7 × 4 mm(3) was demonstrated. The proposed method shows good agreement with 2D MOLLI and the spin-echo reference in phantom. No significant difference was found in the in vivo T1 times estimated using the proposed sequence and the 2D MOLLI technique (myocardium, 330 ± 66 ms versus 319 ± 93 ms; blood pools, 211 ± 68 ms versus 210 ± 98 ms). However, improved homogeneity, as measured using standard deviation of the T1 signal, was observed in the 3D T1 maps. The proposed sequence enables high-resolution 3D T1 mapping after contrast injection during free-breathing with volumetric left ventricle coverage. © 2014 Wiley Periodicals, Inc.

  15. High-field 1H T1 and T2 NMR relaxation time measurements of H2O in homeopathic preparations of quartz, sulfur, and copper sulfate

    NASA Astrophysics Data System (ADS)

    Baumgartner, Stephan; Wolf, Martin; Skrabal, Peter; Bangerter, Felix; Heusser, Peter; Thurneysen, André; Wolf, Ursula

    2009-09-01

    Quantitative meta-analyses of randomized clinical trials investigating the specific therapeutic efficacy of homeopathic remedies yielded statistically significant differences compared to placebo. Since the remedies used contained mostly only very low concentrations of pharmacologically active compounds, these effects cannot be accounted for within the framework of current pharmacology. Theories to explain clinical effects of homeopathic remedies are partially based upon changes in diluent structure. To investigate the latter, we measured for the first time high-field (600/500 MHz) 1H T1 and T2 nuclear magnetic resonance relaxation times of H2O in homeopathic preparations with concurrent contamination control by inductively coupled plasma mass spectrometry (ICP-MS). Homeopathic preparations of quartz (10 c-30 c, n = 21, corresponding to iterative dilutions of 100-10-100-30), sulfur (13 x-30 x, n = 18, 10-13-10-30), and copper sulfate (11 c-30 c, n = 20, 100-11-100-30) were compared to n = 10 independent controls each (analogously agitated dilution medium) in randomized and blinded experiments. In none of the samples, the concentration of any element analyzed by ICP-MS exceeded 10 ppb. In the first measurement series (600 MHz), there was a significant increase in T1 for all samples as a function of time, and there were no significant differences between homeopathic potencies and controls. In the second measurement series (500 MHz) 1 year after preparation, we observed statistically significant increased T1 relaxation times for homeopathic sulfur preparations compared to controls. Fifteen out of 18 correlations between sample triplicates were higher for controls than for homeopathic preparations. No conclusive explanation for these phenomena can be given at present. Possible hypotheses involve differential leaching from the measurement vessel walls or a change in water molecule dynamics, i.e., in rotational correlation time and/or diffusion. Homeopathic preparations

  16. Ventricular cerebrospinal fluid lactate is increased in chronic fatigue syndrome compared with generalized anxiety disorder: an in vivo 3.0 T (1)H MRS imaging study.

    PubMed

    Mathew, Sanjay J; Mao, Xiangling; Keegan, Kathryn A; Levine, Susan M; Smith, Eric L P; Heier, Linda A; Otcheretko, Viktor; Coplan, Jeremy D; Shungu, Dikoma C

    2009-04-01

    Chronic fatigue syndrome (CFS) is a controversial diagnosis because of the lack of biomarkers for the illness and its symptom overlap with neuropsychiatric, infectious, and rheumatological disorders. We compared lateral ventricular volumes derived from tissue-segmented T(1)-weighted volumetric MRI data and cerebrospinal fluid (CSF) lactate concentrations measured by proton MRS imaging ((1)H MRSI) in 16 subjects with CFS (modified US Centers for Disease Control and Prevention criteria) with those in 14 patients with generalized anxiety disorder (GAD) and in 15 healthy volunteers, matched group-wise for age, sex, body mass index, handedness, and IQ. Mean lateral ventricular lactate concentrations measured by (1)H MRSI in CFS were increased by 297% compared with those in GAD (P < 0.001) and by 348% compared with those in healthy volunteers (P < 0.001), even after controlling for ventricular volume, which did not differ significantly between the groups. Regression analysis revealed that diagnosis accounted for 43% of the variance in ventricular lactate. CFS is associated with significantly raised concentrations of ventricular lactate, potentially consistent with recent evidence of decreased cortical blood flow, secondary mitochondrial dysfunction, and/or oxidative stress abnormalities in the disorder.

  17. Human non-contrast T1 values and correlation with histology in diffuse fibrosis

    PubMed Central

    Bull, Sacha; White, Steven K; Piechnik, Stefan K; Flett, Andrew S; Ferreira, Vanessa M; Loudon, Margaret; Francis, Jane M; Karamitsos, Theodoros D; Prendergast, Bernard D; Robson, Matthew D; Neubauer, Stefan; Moon, James C; Myerson, Saul G

    2013-01-01

    Background Aortic stenosis (AS) leads to diffuse fibrosis in the myocardium, which is linked to adverse outcome. Myocardial T1 values change with tissue composition. Objective To test the hypothesis that our recently developed non-contrast cardiac magnetic resonance (CMR) T1 mapping sequence could identify myocardial fibrosis without contrast agent. Design, setting and patients A prospective CMR non-contrast T1 mapping study of 109 patients with moderate and severe AS and 33 age- and gender-matched controls. Methods CMR at 1.5 T, including non-contrast T1 mapping using a shortened modified Look–Locker inversion recovery sequence, was carried out. Biopsy samples for histological assessment of collagen volume fraction (CVF%) were obtained in 19 patients undergoing aortic valve replacement. Results There was a significant correlation between T1 values and CVF% (r=0.65, p=0.002). Mean T1 values were significantly longer in all groups with severe AS (972±33 ms in severe asymptomatic, 1014±38 ms in severe symptomatic) than in normal controls (944±16 ms) (p<0.05). The strongest associations with T1 values were for aortic valve area (r=−0.40, p=0.001) and left ventricular mass index (LVMI) (r=0.36, p=0.008), and these were the only independent predictors on multivariate analysis. Conclusions Non-contrast T1 values are increased in patients with severe AS and further increase in symptomatic compared with asymptomatic patients. T1 values lengthened with greater LVMI and correlated with the degree of biopsy-quantified fibrosis. This may provide a useful clinical assessment of diffuse myocardial fibrosis in the future. PMID:23349348

  18. Human non-contrast T1 values and correlation with histology in diffuse fibrosis.

    PubMed

    Bull, Sacha; White, Steven K; Piechnik, Stefan K; Flett, Andrew S; Ferreira, Vanessa M; Loudon, Margaret; Francis, Jane M; Karamitsos, Theodoros D; Prendergast, Bernard D; Robson, Matthew D; Neubauer, Stefan; Moon, James C; Myerson, Saul G

    2013-07-01

    Aortic stenosis (AS) leads to diffuse fibrosis in the myocardium, which is linked to adverse outcome. Myocardial T1 values change with tissue composition. To test the hypothesis that our recently developed non-contrast cardiac magnetic resonance (CMR) T1 mapping sequence could identify myocardial fibrosis without contrast agent. A prospective CMR non-contrast T1 mapping study of 109 patients with moderate and severe AS and 33 age- and gender-matched controls. CMR at 1.5 T, including non-contrast T1 mapping using a shortened modified Look-Locker inversion recovery sequence, was carried out. Biopsy samples for histological assessment of collagen volume fraction (CVF%) were obtained in 19 patients undergoing aortic valve replacement. There was a significant correlation between T1 values and CVF% (r=0.65, p=0.002). Mean T1 values were significantly longer in all groups with severe AS (972 ± 33 ms in severe asymptomatic, 1014 ± 38 ms in severe symptomatic) than in normal controls (944 ± 16 ms) (p<0.05). The strongest associations with T1 values were for aortic valve area (r=-0.40, p=0.001) and left ventricular mass index (LVMI) (r=0.36, p=0.008), and these were the only independent predictors on multivariate analysis. Non-contrast T1 values are increased in patients with severe AS and further increase in symptomatic compared with asymptomatic patients. T1 values lengthened with greater LVMI and correlated with the degree of biopsy-quantified fibrosis. This may provide a useful clinical assessment of diffuse myocardial fibrosis in the future.

  19. Reference values for healthy human myocardium using a T1 mapping methodology: results from the International T1 Multicenter cardiovascular magnetic resonance study.

    PubMed

    Dabir, Darius; Child, Nicholas; Kalra, Ashwin; Rogers, Toby; Gebker, Rolf; Jabbour, Andrew; Plein, Sven; Yu, Chung-Yao; Otton, James; Kidambi, Ananth; McDiarmid, Adam; Broadbent, David; Higgins, David M; Schnackenburg, Bernhard; Foote, Lucy; Cummins, Ciara; Nagel, Eike; Puntmann, Valentina O

    2014-10-21

    T1 mapping is a robust and highly reproducible application to quantify myocardial relaxation of longitudinal magnetisation. Available T1 mapping methods are presently site and vendor specific, with variable accuracy and precision of T1 values between the systems and sequences. We assessed the transferability of a T1 mapping method and determined the reference values of healthy human myocardium in a multicenter setting. Healthy subjects (n=102; mean age 41 years (range 17-83), male, n=53 (52%)), with no previous medical history, and normotensive low risk subjects (n=113) referred for clinical cardiovascular magnetic resonance (CMR) were examined. Further inclusion criteria for all were absence of regular medication and subsequently normal findings of routine CMR. All subjects underwent T1 mapping using a uniform imaging set-up (modified Look- Locker inversion recovery, MOLLI, using scheme 3(3)3(3)5)) on 1.5 Tesla (T) and 3 T Philips scanners. Native T1-maps were acquired in a single midventricular short axis slice and repeated 20 minutes following gadobutrol. Reference values were obtained for native T1 and gadolinium-based partition coefficients, λ and extracellular volume fraction (ECV) in a core lab using standardized postprocessing. In healthy controls, mean native T1 values were 950±21 msec at 1.5 T and 1052±23 at 3 T. λ and ECV values were 0.44±0.06 and 0.25±0.04 at 1.5 T, and 0.44±0.07 and 0.26±0.04 at 3 T, respectively. There were no significant differences between healthy controls and low risk subjects in routine CMR parameters and T1 values. The entire cohort showed no correlation between age, gender and native T1. Cross-center comparisons of mean values showed no significant difference for any of the T1 indices at any field strength. There were considerable regional differences in segmental T1 values. λ and ECV were found to be dose dependent. There was excellent inter- and intraobserver reproducibility for measurement of native septal T1. We

  20. Mirnov Coil Analysis by Singular Value Decomposition Method in IR-T1 Tokamak

    NASA Astrophysics Data System (ADS)

    Salemi, Mohammad K.; Saadat, Shervin; Ghoranneviss, Mahmoud; Tabadar, Alireza

    2010-10-01

    The spatial and temporal structures of magnetic signal in the tokamak is analyzed using recently developed singular value decomposition (SVD) technique to determine the structure of current perturbation as the discharge progresses. In this work we use SVD technique for that purpose in IR-T1 tokamak.ootnotetextC. Nardonet, ``Multichannel Fluctuation Data Analysis By The Singular Value Decomposition Method Application To MHD Modes In Jet,'' Plasma Physics & Controlled Fusion, V. 34, No. 9, 1992, 1447-1465

  1. Acute stress effects on GABA and glutamate levels in the prefrontal cortex: A 7T (1)H magnetic resonance spectroscopy study.

    PubMed

    Houtepen, L C; Schür, R R; Wijnen, J P; Boer, V O; Boks, M P M; Kahn, R S; Joëls, M; Klomp, D W; Vinkers, C H

    2017-01-01

    There is ample evidence that the inhibitory GABA and the excitatory glutamate system are essential for an adequate response to stress. Both GABAergic and glutamatergic brain circuits modulate hypothalamus-pituitary-adrenal (HPA)-axis activity, and stress in turn affects glutamate and GABA levels in the rodent brain. However, studies examining stress-induced GABA and glutamate levels in the human brain are scarce. Therefore, we investigated the influence of acute psychosocial stress (using the Trier Social Stress Test) on glutamate and GABA levels in the medial prefrontal cortex of 29 healthy male individuals using 7 Tesla proton magnetic resonance spectroscopy. In vivo GABA and glutamate levels were measured before and 30 min after exposure to either the stress or the control condition. We found no associations between psychosocial stress or cortisol stress reactivity and changes over time in medial prefrontal glutamate and GABA levels. GABA and glutamate levels over time were significantly correlated in the control condition but not in the stress condition, suggesting that very subtle differential effects of stress on GABA and glutamate across individuals may occur. However, overall, acute psychosocial stress does not appear to affect in vivo medial prefrontal GABA and glutamate levels, at least this is not detectable with current practice (1)H-MRS.

  2. Determination of water self-diffusion coefficient in complex food products by low field 1H PFG-NMR: comparison between the standard spin-echo sequence and the T1-weighted spin-echo sequence

    NASA Astrophysics Data System (ADS)

    Métais, Angélique; Mariette, François

    2003-12-01

    In 1990, Van Den Enden et al. proposed a method for the determination of water droplet size distributions in emulsions using a pulsed-field-gradient nuclear magnetic resonance (PFG-NMR) T1-weighted stimulated-echo technique. This paper describes both the T1-weighted spin-echo sequence, an improved method based on this earlier work, and, the standard PFG spin-echo sequence. These two methods were compared for water self-diffusion coefficient measurement in the fatty protein concentrate sample used as a 'cheese model.' The transversal and longitudinal relaxation parameters T1 and T2 were determined according to the temperature and investigated for each sample; fat-free protein concentrate sample, pure anhydrous milk fat, and fatty protein concentrate sample. The water self-diffusion in fat-free protein concentrate samples followed a linear behavior. Consequently, the water self-diffusion coefficient could be easily characterized for fat-free protein concentrate samples. However, it seemed more complicated to obtain accurate water self-diffusion in fatty protein concentrate samples since the diffusion-attenuation data were fitted by a bi-exponential function. This paper demonstrates that the implementation of the T1-weighted spin-echo sequence, using the different T1 properties of water and fat phases, allows the accurate determination of water self-diffusion coefficient in a food product. To minimize the contribution of the 1H nuclei in the fat phase on the NMR echo signal, the fat protons were selectively eliminated by an additional 180° pulse. This new method reduces the standard errors of diffusion data obtained with a basic spin-echo technique, by a factor of 10. The effectiveness of the use of the T1-weighted spin-echo sequence to perform accurate water self-diffusion coefficients measurement in fatty products is thus demonstrated.

  3. T1 and T2 values of human neonatal blood at 3 Tesla: Dependence on hematocrit, oxygenation, and temperature.

    PubMed

    Liu, Peiying; Chalak, Lina F; Krishnamurthy, Lisa C; Mir, Imran; Peng, Shin-lei; Huang, Hao; Lu, Hanzhang

    2016-04-01

    Knowledge of blood T1 and T2 is of major importance in many applications of MRI in neonates. However, to date, there has not been a systematic study to examine neonatal blood T1/T2 relaxometry. This present study aims to investigate this topic. Using freshly collected blood samples from human umbilical cord, we performed in vitro experiments under controlled physiological conditions to measure blood T1 and T2 at 3 Tesla (T) and their dependence on several factors, including hematocrit (Hct), oxygenation (Y) and temperature. The arterial T1 in neonates was 1825 ± 184 ms (Hct = 0.42 ± 0.08), longer than that of adult blood. Neonatal blood T1 was strongly dependent on Hct (P < 0.001) and Y (P = 0.005), and the dependence of T1 on Y was more prominent at higher Hct. The arterial T2 of neonatal blood was 191 ms at an Hct of 0.42, which was also longer than adult blood. Neonatal blood T2 was positively associated with blood oxygenation and negatively associated with hematocrit level, and can be characterized by an exchange model. Neonatal blood T1 was also positively associated with temperature (P < 0.001). The values provided in this report may provide important reference and calibration information for sequence optimization and quantification of in vivo neonatal MRI studies. © 2016 Wiley Periodicals, Inc.

  4. [Prognostic value of dynamic monitoring of RUNX1-RUNX1T1 transcript in pediatric acute myeloid leukemia].

    PubMed

    Gao, H T; Zhang, Y; Sun, K; Guo, J M; Chen, Y Q; Chen, X L; Shi, J; Niu, X N; Wang, F; Huo, L

    2017-03-14

    Objective: To investigate the prognostic value of dynamic monitoring of RUNX1-RUNX1T1 transcript in pediatric patients with t (8;21) acute myeloid leukemia (AML) . Methods: The clinical features and RUNX1-RUNX1T1 transcript levels of 55 pediatric t (8;21) AML patients, newly diagnosed from Jan. 2010 to Apr. 2016, were analyzed retrospectively. The relationship between the minimal residual disease (MRD) and prognosis was analysed by dynamic monitoring of RUNX1-RUNX1T1 transcript levels using real-time quantitative PCR (RQ-PCR) technology. Results: The RUNX1-RUNX1T1 transcript levels in bone marrow cells at diagnosis was not related to relapse. After one course of induction therapy, patients with a more than 2 Log reduction of RUNX1-RUNX1T1 transcript levels (>2 Log) had lower 5 years cumulative incidence of relapse (CIR) [ (24.3±8.4) % vs (52.6±9.7) %, χ(2)=9.046, P=0.003], relapse-free survival (RFS) [ (71.6±12.7) % vs (48.1±13.2) %, χ(2)=5.814, P=0.016], and better overall survival (OS) [ (76.9±12.5) % vs (48.9±14.7) %, χ(2)=6.346, P=0.012], compared to patients with a less than 2 Log reduction (a<2 Log) . Multivariate Cox survival analysis suggested that a>2 Log reduction in RUNX1-RUNX1T1 transcript levels after a course of induction therapy was an independent prognostic factor for RFS (HR=0.263, 95%CI 0.081-0.851, P=0.026) and OS (HR=0.214, 95% CI 0.057-0.808, P=0.023) . During consolidation therapy and follow-up period, molecular relapse of 16 cases and hematologic relapse of 13 cases were identified by continuous dynamic monitoring of RUNX1-RUNX1T1 transcript levels, with a median interval of 4.0 (1.5-5.8) months from the molecular relapse to hematologic relapse. 2 cases of molecular relapse who received timely allogeneic hematopoietic stem cell transplantation did not experience hematologic relapse. Conclusion: Dynamic monitoring RUNX1-RUNX1T1 transcript levels by RQ-PCR technique can subdivide patients into relatively low and high risk group, early

  5. Development of qualitative and quantitative analysis methods in pharmaceutical application with new selective signal excitation methods for 13 C solid-state nuclear magnetic resonance using 1 H T1rho relaxation time.

    PubMed

    Nasu, Mamiko; Nemoto, Takayuki; Mimura, Hisashi; Sako, Kazuhiro

    2013-01-01

    Most pharmaceutical drug substances and excipients in formulations exist in a crystalline or amorphous form, and an understanding of their state during manufacture and storage is critically important, particularly in formulated products. Carbon 13 solid-state nuclear magnetic resonance (NMR) spectroscopy is useful for studying the chemical and physical state of pharmaceutical solids in a formulated product. We developed two new selective signal excitation methods in (13) C solid-state NMR to extract the spectrum of a target component from such a mixture. These methods were based on equalization of the proton relaxation time in a single domain via rapid intraproton spin diffusion and the difference in proton spin-lattice relaxation time in the rotating frame ((1) H T1rho) of individual components in the mixture. Introduction of simple pulse sequences to one-dimensional experiments reduced data acquisition time and increased flexibility. We then demonstrated these methods in a commercially available drug and in a mixture of two saccharides, in which the (13) C signals of the target components were selectively excited, and showed them to be applicable to the quantitative analysis of individual components in solid mixtures, such as formulated products, polymorphic mixtures, or mixtures of crystalline and amorphous phases. Copyright © 2012 Wiley Periodicals, Inc.

  6. Difference between Extra- and Intracellular T1 Values of Carboxylic Acids Affects the Quantitative Analysis of Cellular Kinetics by Hyperpolarized NMR.

    PubMed

    Karlsson, Magnus; Jensen, Pernille Rose; Ardenkjaer-Larsen, Jan Henrik; Lerche, Mathilde H

    2016-10-17

    Incomplete knowledge of the longitudinal relaxation time constant (T1 ) leads to incorrect assumptions in quantitative kinetic models of cellular systems, studied by hyperpolarized real-time NMR. Using an assay that measures the intracellular signal of small carboxylic acids in living cells, the intracellular T1 of the carboxylic acid moiety of acetate, keto-isocaproate, pyruvate, and butyrate was determined. The intracellular T1 is shown to be up to four-fold shorter than the extracellular T1 . Such a large difference in T1 values between the inside and the outside of the cell has significant influence on the quantification of intracellular metabolic activity. It is expected that the significantly shorter T1 value of the carboxylic moieties inside cells is a result of macromolecular crowding. An artificial cytosol has been prepared and applied to predict the T1 of other carboxylic acids. We demonstrate the value of this prediction tool.

  7. The influence of microvascular injury on native T1 and T2* relaxation values after acute myocardial infarction: implications for non-contrast-enhanced infarct assessment.

    PubMed

    Robbers, Lourens F H J; Nijveldt, Robin; Beek, Aernout M; Teunissen, Paul F A; Hollander, Maurits R; Biesbroek, P Stefan; Everaars, Henk; van de Ven, Peter M; Hofman, Mark B M; van Royen, Niels; van Rossum, Albert C

    2017-08-18

    Native T1 mapping and late gadolinium enhancement (LGE) imaging offer detailed characterisation of the myocardium after acute myocardial infarction (AMI). We evaluated the effects of microvascular injury (MVI) and intramyocardial haemorrhage on local T1 and T2* values in patients with a reperfused AMI. Forty-three patients after reperfused AMI underwent cardiovascular magnetic resonance imaging (CMR) at 4 [3-5] days, including native MOLLI T1 and T2* mapping, STIR, cine imaging and LGE. T1 and T2* values were determined in LGE-defined regions of interest: the MI core incorporating MVI when present, the core-adjacent MI border zone (without any areas of MVI), and remote myocardium. Average T1 in the MI core was higher than in the MI border zone and remote myocardium. However, in the 20 (47%) patients with MVI, MI core T1 was lower than in patients without MVI (MVI 1048±78ms, no MVI 1111±89ms, p=0.02). MI core T2* was significantly lower in patients with MVI than in those without (MVI 20 [18-23]ms, no MVI 31 [26-39]ms, p<0.001). The presence of MVI profoundly affects MOLLI-measured native T1 values. T2* mapping suggested that this may be the result of intramyocardial haemorrhage. These findings have important implications for the interpretation of native T1 values shortly after AMI. • Microvascular injury after acute myocardial infarction affects local T1 and T2* values. • Infarct zone T1 values are lower if microvascular injury is present. • T2* mapping suggests that low infarct T1 values are likely haemorrhage. • T1 and T2* values are complimentary for correctly assessing post-infarct myocardium.

  8. UV/vis, 1H, and 13C NMR spectroscopic studies to determine mangiferin pKa values.

    PubMed

    Gómez-Zaleta, Berenice; Ramírez-Silva, María Teresa; Gutiérrez, Atilano; González-Vergara, Enrique; Güizado-Rodríguez, Marisol; Rojas-Hernández, Alberto

    2006-07-01

    The acid constants of mangiferin (a natural xanthonoid) in aqueous solution were determined through an UV/vis spectroscopic study employing the SQUAD program as a computational tool. A NMR study complements the pK(a) values assignment and evidences a H-bridge presence on 1-C. The chemical model used was consistent with the experimental data obtained. The pK(a) values determined with this procedure were as follows: H(4)(MGF)=H(3)(MGF)(-)+H(+), pKa1 (6-H)=6.52+/-0.06; H(3)(MGF)(-)=H(2)(MGF)(2-)+H(+), pKa2 (3-H)=7.97+/-0.06; H(2)(MGF)(2-)=H(MGF)(3-)+H(+), pKa3 (7-H)=9.44+/-0.04; H(MGF)(3-)=(MGF)(4-)+H(+), pKa4 (1-H)=12.10+/-0.01; where it has been considered mangiferin C(19)H(18)O(11) as H(4)(MGF). Mangiferin UV/vis spectral behavior, stability study in aqueous solution as well as NMR spectroscopy studies: one-dimensional (1)H,(13)C, 2D correlated (1)H/(13)C performed by (g)-HSQC and (g)-HMBC methods; are also presented. pK(a) values determination of H(4)(MGF) in aqueous solution is a necessary contribution to subsequent pharmacokinetic study, and a step towards the understanding of its biological effects.

  9. Reliability of 7T (1) H-MRS measured human prefrontal cortex glutamate, glutamine, and glutathione signals using an adapted echo time optimized PRESS sequence: A between- and within-sessions investigation.

    PubMed

    Lally, Níall; An, Li; Banerjee, Dipavo; Niciu, Mark J; Luckenbaugh, David A; Richards, Erica M; Roiser, Jonathan P; Shen, Jun; Zarate, Carlos A; Nugent, Allison C

    2016-01-01

    To ascertain the mechanisms of neuropsychiatric illnesses and their treatment, accurate and reliable imaging techniques are required; proton magnetic resonance spectroscopy ((1) H-MRS) can noninvasively measure glutamatergic function. Evidence suggests that aberrant glutamatergic signaling plays a role in numerous psychopathologies. Until recently, overlapping glutamatergic signals (glutamate, glutamine, and glutathione) could not easily be separated. However, the advent of novel pulse sequences and higher field magnetic resonance imaging (MRI) allows more precise resolution of overlapping glutamatergic signals, although the question of signal reliability remains undetermined. At 7T MR, we acquired (1) H-MRS data from the medial pregenual anterior cingulate cortex of healthy volunteers (n = 26) twice on two separate days. An adapted echo time optimized point-resolved spectroscopy sequence, modified with the addition of a J-suppression pulse to attenuate N-acetyl-aspartate multiplet signals at 2.49 ppm, was used to excite and acquire the spectra. In-house software was used to model glutamate, glutamine, and glutathione, among other metabolites, referenced to creatine. Intraclass correlation coefficients (ICCs) were computed for within- and between-session measurements. Within-session measurements of glutamate, glutamine, and glutathione were on average reliable (ICCs ≥0.7). As anticipated, ICCs for between-session values of glutamate, glutamine, and glutathione were slightly lower but nevertheless reliable (ICC >0.62). A negative correlation was observed between glutathione concentration and age (r(24)  = -0.37; P < 0.05), and a gender effect was noted on glutamine and glutathione. The adapted sequence provides good reliability to measure glutamate, glutamine, and glutathione signals. © 2015 Wiley Periodicals, Inc.

  10. Diagnostic value of brain chronic black holes on T1-weighted MR images in clinically isolated syndromes.

    PubMed

    Mitjana, Raquel; Tintoré, Mar; Rocca, Maria A; Auger, Cristina; Barkhof, Frederik; Filippi, Massimo; Polman, Chris; Fazekas, Franz; Huerga, Elena; Montalban, Xavier; Rovira, Alex

    2014-10-01

    Non-enhancing black holes (neBHs) are more common in multiple sclerosis (MS) patients with longer disease durations and progressive disease subtypes. Our aim was to analyse the added value of neBHs in patients with clinically isolated syndromes (CISs) for predicting conversion to clinically definite MS (CDMS). Patients were classified based on the presence or absence of neBHs and on the number of Barkhof-Tintoré (B-T) criteria fulfilled. Dissemination in space (DIS) was defined as the presence of at least three of the four B-T criteria. Dissemination in time (DIT)1 was defined by simultaneous presence of enhancing and non-enhancing lesions. DIT2 was defined by simultaneous presence of neBHs and T2 lesions not apparent on T1-weighted images. Focal T2-hyperintense brain lesions were identified in 87.7% of the 520 CIS patients, and 41.4% of them presented at least one neBH. Patients meeting DIS, DIT1, and DIT2 had a significantly higher rate of conversion to CDMS. After adjusting for DIS, only patients who fulfilled DIT1 preserved a significant increase in CDMS conversion. Non-enhancing black holes in CIS patients are associated with a higher risk of conversion to CDMS. However, the predictive value of this finding is lost when added to the DIS criteria. © The Author(s) 2014.

  11. Evaluation of the relationship between T1ρ and T2 values and patella cartilage degeneration in patients of the same age group.

    PubMed

    Nishioka, Hiroaki; Hirose, Jun; Okamoto, Nobukazu; Okada, Tatsuya; Oka, Kiyoshi; Taniwaki, Takuya; Nakamura, Eiichi; Yamashita, Yasuyuki; Mizuta, Hiroshi

    2015-03-01

    The aim of this study was to investigate the association between the T1ρ and T2 values and the progression of cartilage degeneration in patients of the same age group. Sagittal T1ρ and T2 mapping and three-dimensional (3D) gradient-echo images were obtained from 78 subjects with medial knee osteoarthritis (OA). The degree of patella cartilage degeneration was classified into four groups using MRI-based grading: apparently normal cartilage, mild OA, moderate OA, and severe OA group. We measured the T1ρ and T2 values (ms) in the regions of interest set on the full-thickness patella cartilage. Then, we analyzed the relationship between the T1ρ and T2 values and the degree of patella cartilage degeneration. There were no significant differences in age among the four groups. Both the T1ρ and T2 values showed a positive correlation with the degree of OA progression (ρ=0.737 and ρ=0.632, respectively). By comparison between the apparently normal cartilage and the mild OA groups, there were significant differences in the T1ρ mapping, but not in the T2 mapping. Our study confirmed that T1ρ and T2 mapping can quantitatively evaluate the degree of patella cartilage degeneration in patients within the same age group. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  12. Value of the Hemorrhage Exclusion Sign on T1-weighted Prostate MR Images for the Detection of Prostate Cancer

    PubMed Central

    Barrett, Tristan; Akin, Oguz; Goldman, Debra A.; Hricak, Hedvig

    2012-01-01

    Purpose: To retrospectively determine the prevalence and positive predictive value (PPV) of the hemorrhage exclusion sign on T1-weighted magnetic resonance (MR) images in conjunction with findings on T2-weighted images in the detection of prostate cancer, with use of whole-mount step-section pathologic specimens from prostatectomy as the reference standard. Materials and Methods: The institutional review board approved this retrospective study, which was compliant with HIPAA, and the requirement to obtain informed consent was waived. Two hundred ninety-two patients with biopsy-proved prostate cancer underwent endorectal MR imaging followed by prostatectomy. The hemorrhage exclusion sign was defined as the presence of a well-defined area of low signal intensity surrounded by areas of high signal intensity on T1-weighted images. Two readers independently assessed the presence and extent of postbiopsy changes and the hemorrhage exclusion sign. The presence of a corresponding area of homogeneous low signal intensity on T2-weighted images was also recorded. The prevalence and PPV of the hemorrhage exclusion sign were calculated. Results: Readers 1 and 2 found postbiopsy changes in the peripheral zone in 184 (63%) and 189 (64.7%) of the 292 patients, respectively. In these patients, the hemorrhage exclusion sign was observed in 39 of 184 patients (21.2%) by reader 1 and 36 of 189 patients (19.0%) by reader 2. A corresponding area of homogeneous low signal intensity was seen on T2-weighted images in the same location as the hemorrhage exclusion sign in 23 of 39 patients (59%) by reader 1 and 19 of 36 patients (53%) by reader 2. The PPV of the hemorrhage exclusion sign alone was 56% (22 of 39 patients) for reader 1 and 50% (18 of 36 patients) for reader 2 but increased to 96% (22 of 23 patients) and 95% (18 of 19 patients) when the sign was identified in an area of homogeneous low signal intensity on T2-weighted images. Conclusion: Postbiopsy change is a known pitfall in

  13. In-vivo assessment of normal T1 values of the right-ventricular myocardium by cardiac MRI.

    PubMed

    Kawel-Boehm, N; Dellas Buser, T; Greiser, A; Bieri, O; Bremerich, J; Santini, F

    2014-02-01

    To test feasibility of myocardial T1 mapping of the right ventricle (RV) at systole when myocardium is more compact and to determine the most appropriate imaging plane. 20 healthy volunteers (11 men; 33 ± 8 years) were imaged on a 1.5T scanner (MAGNETOM Avanto, Siemens AG, Erlangen, Germany). A modified look-locker inversion-recovery sequence was acquired at mid-ventricular short axis (SAX), as horizontal long-axis view and as transversal view at systole (mean trigger time 363 ± 37 ms). Myocardial T1 time of the left-ventricular and RV myocardium was measured within a region of interest (ROI) on generated T1-maps. The most appropriate imaging plane for the RV was determined by the ability to draw a ROI including the largest amount of myocardium without including adjacent tissue or blood. At systole, when myocardium is thicker, measurements of the RV myocardium were feasible in 18/20 subjects. Average size of the ROI was 0.42 ± 0.28 cm(2). In 10/18 subjects, short axis was the most appropriate imaging plane to obtain measurements (p = 0.034). Average T1 time of the RV myocardium was 1,016 ± 61 ms, and average T1 of the left-ventricular (LV) was 956 ± 25 ms (p < 0.001). T1 mapping of the RV myocardium is feasible during systole in the majority of healthy subjects but with a small ROI only. SAX plane was the optimal imaging plane in the majority of subjects. Native myocardial T1 time of the RV is significantly longer compared to the LV, which might be explained by the naturally higher collagen content of the RV.

  14. T1, T2 Mapping and Extracellular Volume Fraction (ECV): Application, Value and Further Perspectives in Myocardial Inflammation and Cardiomyopathies.

    PubMed

    Roller, F C; Harth, S; Schneider, C; Krombach, G A

    2015-09-01

    Cardiac magnetic resonance imaging (CMRI) is a versatile diagnostic tool. One of its main advantages is the possibility of tissue characterization. T1-weighted images for scar and T2-weighted images for edema visualization are key methods for tissue characterization. Otherwise these sequences are strongly limited for the detection of diffuse myocardial pathologies. Recently, rapid technical innovations have generated new techniques. T1, T2 mapping and evaluation of the extracellular volume fraction (ECV) allow quantification of diffuse myocardial pathologies and showed great potential in the visualization of fibrosis, edema, amyloid, iron overload and lipid. In the future these techniques might enable the detection of early cardiac involvement, even act as a prognosticator. Moreover, therapy monitoring and follow-up might be possible due to versatile parameter quantification with these new techniques. CMR allows for tissue characterization via T1- and T2-weighted sequences. In cases of diffuse, global myocardial pathologies, correct image interpretation with traditional CMR sequences might be difficult. T1, T2 mapping and ECV can quantify diffuse, global myocardial pathologies. Alterations of myocardial T1 and T2 relaxation times occur in various myocardial diseases (e.g. acute myocarditis). In the future mapping might act as a prognosticator or therapy monitoring tool. © Georg Thieme Verlag KG Stuttgart · New York.

  15. Diagnostic and Prognostic Value of CMR T1-Mapping in Patients With Heart Failure and Preserved Ejection Fraction.

    PubMed

    Rommel, Karl-Philipp; Lücke, Christian; Lurz, Philipp

    2017-03-14

    Heart failure with preserved ejection fraction (HFpEF) presents a major challenge in modern cardiology. Although this syndrome is of increasing prevalence and is associated with unfavorable outcomes, treatment trials have failed to establish effective therapies. Currently, solutions to this dilemma are being investigated, including categorizing and characterizing patients more diversely to individualize treatment. In this regard, new imaging techniques might provide important information. Diastolic dysfunction is a diagnostic and pathophysiological cornerstone in HFpEF and is believed to be caused by systemic inflammation with the development of interstitial myocardial fibrosis and myocardial stiffening. Cardiac magnetic resonance (CMR) T1-mapping is a novel tool, which allows noninvasive quantification of the extracellular space and diffuse myocardial fibrosis. This review provides an overview of the potential of myocardial tissue characterization with CMR T1 mapping in HFpEF patients, outlining its diagnostic and prognostic implications and discussing future directions. We conclude that CMR T1 mapping is potentially an effective tool for patient characterization in large-scale epidemiological, diagnostic, and therapeutic HFpEF trials beyond traditional imaging parameters.

  16. Comparison of myocardial T1 and T2 values in 3 T with T2* in 1.5 T in patients with iron overload and controls.

    PubMed

    Camargo, Gabriel C; Rothstein, Tamara; Junqueira, Flavia P; Fernandes, Elsa; Greiser, Andreas; Strecker, Ralph; Pessoa, Viviani; Lima, Ronaldo S L; Gottlieb, Ilan

    2016-05-01

    Myocardial iron quantification remains limited to 1.5 T systems with T2* measurement. The present study aimed at comparing myocardial T2* values at 1.5 T to T1 and T2 mapping at 3.0 T in patients with iron overload and healthy controls. A total of 17 normal volunteers and seven patients with a history of myocardial iron overload were prospectively enrolled. Mid-interventricular septum T2*, native T1 and T2 times were quantified on the same day, using a multi-echo gradient-echo sequence at 1.5 T and T1 and T2 mapping sequences at 3.0 T, respectively. Subjects with myocardial iron overload (T2* < 20 ms) in comparison with those without had significantly lower mean myocardial T1 times (868.9 ± 120.2 vs. 1170.3 ± 25.0 ms P = 0.005 respectively) and T2 times (34.9 ± 4.7 vs. 45.1 ± 2.0 ms P = 0.007 respectively). 3 T T1 and T2 times strongly correlated with 1.5 T, T2* times (Pearson's r = 0.95 and 0.91 respectively). T1 and T2 measures presented less variability than T2* in inter- and intra-observer analysis. Native myocardial T1 and T2 times at 3 T correlate closely with T2* times at 1.5 T and may be useful for myocardial iron overload quantification.

  17. Joint inversion of T1-T2 spectrum combining the iterative truncated singular value decomposition and the parallel particle swarm optimization algorithms

    NASA Astrophysics Data System (ADS)

    Ge, Xinmin; Wang, Hua; Fan, Yiren; Cao, Yingchang; Chen, Hua; Huang, Rui

    2016-01-01

    With more information than the conventional one dimensional (1D) longitudinal relaxation time (T1) and transversal relaxation time (T2) spectrums, a two dimensional (2D) T1-T2 spectrum in a low field nuclear magnetic resonance (NMR) is developed to discriminate the relaxation components of fluids such as water, oil and gas in porous rock. However, the accuracy and efficiency of the T1-T2 spectrum are limited by the existing inversion algorithms and data acquisition schemes. We introduce a joint method to inverse the T1-T2 spectrum, which combines iterative truncated singular value decomposition (TSVD) and a parallel particle swarm optimization (PSO) algorithm to get fast computational speed and stable solutions. We reorganize the first kind Fredholm integral equation of two kernels to a nonlinear optimization problem with non-negative constraints, and then solve the ill-conditioned problem by the iterative TSVD. Truncating positions of the two diagonal matrices are obtained by the Akaike information criterion (AIC). With the initial values obtained by TSVD, we use a PSO with parallel structure to get the global optimal solutions with a high computational speed. We use the synthetic data with different signal to noise ratio (SNR) to test the performance of the proposed method. The result shows that the new inversion algorithm can achieve favorable solutions for signals with SNR larger than 10, and the inversion precision increases with the decrease of the components of the porous rock.

  18. Age and sex corrected normal reference values of T1, T2 T2* and ECV in healthy subjects at 3T CMR.

    PubMed

    Roy, Clotilde; Slimani, Alisson; de Meester, Christophe; Amzulescu, Mihaela; Pasquet, Agnès; Vancraeynest, David; Vanoverschelde, Jean-Louis; Pouleur, Anne-Catherine; Gerber, Bernhard L

    2017-09-21

    Myocardial T1, T2 and T2* imaging techniques become increasingly used in clinical practice. While normal values for T1, T2 and T2* times are well established for 1.5 Tesla (T) cardiovascular magnetic resonance (CMR), data for 3T remain scarce. Therefore we sought to determine normal reference values relative to gender and age and day to day reproducibility for native T1, T2, T2* mapping and extracellular volume (ECV) at 3T in healthy subjects. After careful exclusion of cardiovascular abnormality, 75 healthy subjects aged 20 to 90 years old (mean 56 ± 19 years, 47% women) underwent left-ventricular T1 (3-(3)-3-(3)-5 MOLLI)), T2 (8 echo- spin echo-imaging) and T2 * (8 echo gradient echo imaging) mapping at 3T CMR (Philips Ingenia 3T and computation of extracellular volume after administration of 0.2 mmol/kg Gadovist). Inter- and intra-observer reproducibility was estimated by intraclass correlation coefficient (ICC). Day to day reproducibility was assessed in 10 other volunteers. Mean myocardial T1 at 3T was 1122 ± 57 ms, T2 52 ± 6 ms, T2* 24 ± 5 ms and ECV 26.6 ± 3.2%. T1 (1139 ± 37 vs 1109 ± 73 ms, p < 0.05) and ECV (28 ± 3 vs 25 ± 2%, p < 0.001), but not T2 (53 ± 8 vs 51 ± 4, p = NS) were significantly greater in age matched women than in men. T1 (r = 0.40, p < 0.001) and ECV (r = 0.37, p = 0.001) increased, while T2 decreased significantly (r = -0.25, p < 0.05) with increasing age. T2* was not influenced by either gender or age. Intra and inter-observer reproducibility was high (ICC ranging between 0.81-0.99), and day to day coefficient of variation was low (6.2% for T1, 7% for T2, 11% for T2* and 11.5% for ECV). We provide normal myocardial T2, T2*,T1 and ECV reference values for 3T CMR which are significantly different from those reported at 1.5 Tesla CMR. Myocardial T1 and ECV values are gender and age dependent. Measurement had high inter and intra-observer reproducibility and good day

  19. Measurement of the individual pKa values of acidic residues of hen and turkey lysozymes by two-dimensional 1H NMR.

    PubMed Central

    Bartik, K; Redfield, C; Dobson, C M

    1994-01-01

    The pH dependence of the two-dimensional 1H nuclear magnetic resonance spectra of hen and turkey egg-white lysozymes has been recorded over the pH range 1-7. By monitoring the chemical shifts of the resonances of the various protons of ionizable residues, individual pKa values for the acidic residues have been determined for both proteins. The pKa values are displaced, with the exception of those of the residues in the active site cleft, by an average of 1 unit to low pH compared to model compounds. PMID:8038389

  20. Environmental controls on the 2H/1H values of terrestrial leaf waxes in the eastern Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Shanahan, Timothy M.; Hughen, Konrad A.; Ampel, Linda; Sauer, Peter E.; Fornace, Kyrstin

    2013-10-01

    The hydrogen isotope composition of plant waxes preserved in lacustrine sediments is a potentially valuable tool for reconstructing paleoenvironmental changes in the Arctic. However, in contrast to the mid- and low-latitudes, significantly less effort has been directed towards understanding the factors controlling D/H fractionation in high latitude plant waxes and the impact of these processes on the interpretation of sedimentary leaf wax δD records. To better understand these processes, we examined the D/H ratios of long chain fatty acids in lake surface sediments spanning a temperature and precipitation gradient on Baffin Island in the eastern Canadian Arctic. D/H ratios of plant waxes increase with increasing temperature and aridity, with values ranging from -240‰ to -160‰ over the study area. Apparent fractionation factors between n-alkanoic acids in Arctic lake sediments and precipitation(εFA-ppt) are less negative than those of mid-latitude lakes and modern plants by 25‰ to 65‰, consistent with n-alkane data from modern Arctic plants (Yang et al., 2011). Furthermore, εFA-ppt values from Arctic lakes become systematically more positive with increasing evaporation, in contrast to mid-latitude sites, which show little to no change in fractionation with aridity. These data are consistent with enhanced water loss and isotope fractionation at higher latitude in the Arctic summer, when continuous sunlight supports increased daily photosynthesis. The dominant control on δDFA variations on Baffin Island is temperature. However, changing εFA-ppt result in steeper δDFA-temperature relationships than observed for modern precipitation. The application of this δDFA-based paleotemperature calibration to existing δDFA records from Baffin Island produces much more realistic changes in late Holocene temperature and highlights the importance of these effects in influencing the interpretation of Arctic δDFA records. A better understanding of the controls on

  1. Value of metastin receptor immunohistochemistry in predicting metastasis after radical nephrectomy for pT1 clear cell renal cell carcinoma.

    PubMed

    Shoji, Sunao; Nakano, Mayura; Tomonaga, Tetsuro; Kim, Hakushi; Hanai, Kazuya; Usui, Yukio; Nagata, Yoshihiro; Miyazawa, Masaki; Sato, Haruhiro; Tang, Xian Yang; Osamura, Yoshiyuki Robert; Uchida, Toyoaki; Terachi, Toshiro; Takeya, Koichi

    2013-06-01

    KISS-1 is a metastasis-suppressor gene of human melanoma, and encodes metastin, which was identified as the ligand of a G-protein-coupled receptor (metastin receptor). The precursor protein is cleaved to 54 amino acids, which may be further truncated into carboxy-terminal fragments. Previous studies showed that lack of metastin receptor in clear cell renal cell carcinoma (RCC) is associated with tumor progression, but the prediction of metastasis in patients with pT1 clear cell RCC after radical nephrectomy is difficult. The objective of this study was to evaluate the usefulness of metastin receptor immunohistochemistry in predicting metastasis after nephrectomy for pT1 clear cell RCC. After verification of the correlation between immunostaining and mRNA expression, we evaluated the clinical value of metastin receptor immunohistochemistry. Fifty-four patients were enrolled in this study; following radical nephrectomy, seven patients were found to have lung metastasis. The sensitivity, specificity, positive predictive value, and negative predictive value with negative immunostaining of metastin receptor were 85.7, 97.6, 46.2, and 97.6 %, respectively. Metastasis-free survival rates were significantly higher in patients with positive staining (97.6 %) than in patients with negative staining (53.8 %) (P < 0.001). In univariate analysis for metastasis-free survival, negative immunostaining of metastin receptor was a significant risk factor for metastasis (P = 0.001). Furthermore, negative immunostaining of metastin receptor was an independent predictor for metastasis in multivariate analysis (hazard ratio, 3.735; 95 % CI 0.629-22.174; P = 0.002). In conclusion, our study suggests that negative expression of metastin receptor in clear cell RCC is significantly related to metastasis.

  2. Properties of sesame oil by detailed 1H and 13C NMR assignments before and after ozonation and their correlation with iodine value, peroxide value, and viscosity measurements.

    PubMed

    Sega, Alessandro; Zanardi, Iacopo; Chiasserini, Luisa; Gabbrielli, Alessandro; Bocci, Velio; Travagli, Valter

    2010-02-01

    Gaseous ozone chemically reacts with unsaturated triglyceride substrates leading to ozonated derivatives with a wide potential applications, ranging from the petrochemical to the pharmaceutical industry. To date, an ultimate understanding of the ozone reactivity during sesame oil ozonation process as well as detailed (1)H and (13)C NMR assignments are lacking. A practical advantage of NMR is that a single NMR sample measurement can explain many issues, while similar analysis by traditional methods may require several independent and time-consuming measurements. Moreover, significant relationships among NMR spectra and both conventional chemical analysis and viscosity measurements have been found. Eventually, NMR could play an important role for quality attributes of ozonated oil derivatives.

  3. Cardiac T1 Imaging

    PubMed Central

    Jerosch-Herold, Michael; Kwong, Raymond Y.

    2014-01-01

    T1 mapping of the heart has evolved into a valuable tool to evaluate myocardial tissue properties, with or without contrast injection, including assessment of myocardial edema and free water content, extra-cellular volume (expansion), and most recently cardiomyocyte hypertrophy. The MRI pulse sequence techniques developed for these applications have had to address at least two important considerations for cardiac applications: measure magnetization inversion recoveries during cardiac motion with sufficient temporal resolution for the shortest expected T1 values, and, secondly, obtain these measurements within a time during which a patient can comfortably suspend breathing. So-called Look-Locker techniques, and variants thereof, which all sample multiple points of a magnetization recovery after each magnetization preparation have therefore become a mainstay in this field. The rapid pace of advances and new findings based on cardiac T1 mapping for assessment of diffuse fibrosis, or myocardial edema show that these techniques enrich the capabilities of MRI for myocardial tissue profiling, which is arguably unmatched by other cardiac imaging modalities. PMID:24509619

  4. Anthropomorphic 1H MRS head phantom.

    PubMed

    Rice, J R; Milbrandt, R H; Madsen, E L; Frank, G R; Boote, E J; Blechinger, J C

    1998-07-01

    An anthropomorphic 1H MRS head phantom has been developed which mimics the in vivo structure, metabolite concentrations, and relaxation times (for both water and metabolites) of human brain tissue. Different brain regions and two tumor types, fluid-containing ventricles, and air-filled sinus, and subcutaneous fat are all simulated. The main tissue-mimicking materials are gelatin/agar mixtures with metabolites and several other ingredients added. Their composition and method of production are thoroughly described. T1's and T2's of water in the phantom are very close to in vivo values, and metabolite T1's and T2's are considerably more realistic than those in aqueous solutions. Spectra and relaxation times for the pig brain were also acquired and compare well with those of the phantom. The realistic properties of this phantom should be useful for testing spectral quantitation and localization.

  5. Prognostic value of T1-mapping in TAVR patients: extra-cellular volume as a possible predictor for peri- and post-TAVR adverse events.

    PubMed

    Nadjiri, Jonathan; Nieberler, Hanna; Hendrich, Eva; Will, Albrecht; Pellegrini, Costanza; Husser, Oliver; Hengstenberg, Christian; Greiser, Andreas; Martinoff, Stefan; Hadamitzky, Martin

    2016-11-01

    The benefit of a transcatheter aortic valve replacement (TAVR) can differ in patients, and therapy bears severe risks. High-degree aortic stenosis can lead to cardiac damage such as diffuse myocardial fibrosis, evaluable by extra-cellular volume (ECV) in CMR. Therefore, fibrosis might be a possible risk factor for unfavorable outcome after TAVR. We sought to assess the prognostic value of T1-mapping and ECV to predict adverse events during and after TAVR. The study population consisted of patients undergoing clinically indicated TAVR by performing additional CMR with native and contrast-enhanced T1-mapping sequences for additional evaluation of ECV. Study endpoints were congestive heart failure (CHF) and TAVR-associated conduction abnormalities defined as new onset of left bundle branch block (LBBB), AV-Block or implantation of a pacemaker. 94 patients were examined and followed. Median follow up time was 187 days (IQR 79-357 days). ECV was increased (>30 %) in 38 patients (40 %). There was no significant correlation between ECV and death, Hazard ratio (HR) 0.847 (95 % CI 0.335; 2.14), p = 0.72. ECV in patients with subsequent CHF was higher than in those without an event (33.5 ± 4.6 and 29.1 ± 4.1 %, respectively), but the difference just did not reach the level of significance HR 2.16 (95 % CI 0.969; 4.84), p = 0.06. Patients with post-TAVR conduction abnormality (LBBB, AV-block or pacemaker implantation) had statistically relevant lower ECV values compared to those without an event. Patients with an event had a mean ECV of 28.1 ± 3.16 %; patients without an event had a mean ECV of 29.8 ± 4.53, HR 0.56 (95 % CI 0.32; 0.96), p = 0.036. In this study, elevated myocardial ECV is a predictor of CHF by trend; CMR may be helpful in identifying patients with a high risk for post-TAVR cardiac decompensation benefitting from an intensified post-interventional surveillance. Patients with post-TAVR conductions abnormalities

  6. Determination of pKa values of some novel benzimidazole salts by using a new approach with (1)H NMR spectroscopy.

    PubMed

    Mumcu, Akın; Küçükbay, Hasan

    2015-12-01

    Benzimidazoles and their derivatives including imidazole are studied widely because they exist in the structure of natural products and different drugs. pKa values are extremely important for drug discovery and improvement in order to determine pharmacokinetic and pharmacodynamic features such as permeation through biological barriers, interactions with the target area or side effects. Acid-base features (pKa ) have great importance not only for physiological characteristics but also for being used as a ligand or changing physico-chemical features by turning benzimidazoles into salts. Within the scope of this study, a variety of new benzimidazole salts were synthesized, and their characterizations were made by NMR spectroscopy, FTIR spectroscopy and element analysis techniques. The pKa values of synthesized benzimidazole salts were determined by inflection point approach using integration values obtained with (1) H NMR spectroscopy and Henderson-Hasselbalch analysis. pKa values of some benzimidazole salts were also determined by potentiometric methods in order to compare those of NMR spectroscopy results.

  7. Native T1 value in the remote myocardium is independently associated with left ventricular dysfunction in patients with prior myocardial infarction.

    PubMed

    Nakamori, Shiro; Alakbarli, Javid; Bellm, Steven; Motiwala, Shweta R; Addae, Gifty; Manning, Warren J; Nezafat, Reza

    2017-10-01

    To compare remote myocardium native T1 in patients with chronic myocardial infarction (MI) and controls without MI and to elucidate the relationship of infarct size and native T1 in the remote myocardium for the prediction of left ventricular (LV) systolic dysfunction after MI. A total of 41 chronic MI (18 anterior MI) patients and 15 age-matched volunteers with normal LV systolic function and no history of MI underwent cardiac magnetic resonance imaging (MRI) at 1.5T. Native T1 map was performed using a slice interleaved T1 mapping and late gadolinium enhancement (LGE) imaging. Cine MR was acquired to assess LV function and mass. The remote myocardium native T1 time was significantly elevated in patients with prior MI, compared to controls, for both anterior MI and nonanterior MI (anterior MI: 1099 ± 30, nonanterior MI: 1097 ± 39, controls: 1068 ± 25 msec, P < 0.05). Remote myocardium native T1 moderately correlated with LV volume, mass index, and ejection fraction (r = 0.38, 0.50, -0.49, respectively, all P < 0.05). LGE infarct size had a moderate correlation with reduced LV ejection fraction (r = -0.33, P < 0.05), but there was no significant association between native T1 and infarct size. Native T1 time in the remote myocardium was independently associated with reduced LV ejection fraction, after adjusting for age, gender, infarct size, and comorbidity (β = -0.34, P = 0.03). In chronic MI, the severity of LV systolic dysfunction after MI is independently associated with native T1 in the remote myocardium. Diffuse myocardial fibrosis in the remote myocardium may play an important pathophysiological role of post-MI LV dysfunction. 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017;46:1073-1081. © 2017 International Society for Magnetic Resonance in Medicine.

  8. Prognostic value of quantitative cytometry in a series of 415 T1T2/N0N1/M0 breast cancer patients--preliminary results.

    PubMed

    Bolla, M; Seigneurin, D; Winckel, P; Marron-Charrière, J; Panh, M H; Pasquier, D; Ch-edin, M; Payan, R; Merlin, F; Colonna, M

    1996-09-01

    Identifying prognostic markers in local regional breast carcinomas remains an important challenge today. DNA content obtained by flow cytometry, has been found to be of prognostic value; results with other methods remain less clear. This report describes DNA image cytometry patterns which are assessed with respect to disease-free survival. From June 1982 to December 1992, 415 patients under 75 years of age, without any previous or synchronous carcinoma, suffering from an invasive breast cancer classified as T1 (52.8%), T2 (47.2%), N0 (65.1%) N1 (34.9%), MO according to clinical TNM staging, were enrolled in this study. The median age was 53 (28-75) and 58.8% of the patients were premenopausal; 85.3% underwent a breast conservative procedure and 14.7% a modified radical mastectomy followed by postoperative irradiation. Histological axillary lymph node status, Scarff-Bloom grade and/or cytological grade and, oestrogen receptor content were used in decision-making for adjuvant treatment: hormonotherapy (48%) or chemotherapy (18.8%). Imprints were taken from the macroscopically visible lesion at the time of surgery, and a Feulgen staining was carried out on air dried smears to be analysed using the Samba 200 cell image processor (Alcatel TITN, France). Five parameters were systematically assessed: proliferation index; DNA histogram, integrated optical density, DNA malignancy grade, ploidy balance. With a median follow-up of 36 months (0-105), proliferation index (P = 0.0008), DNA histogram (P = 0.0017), integrated optical density (IOD) (P = 0.018) and DNA malignancy grade (P = 0.017) had a significant prognostic value on disease-free survival estimated by the Kaplan-Meier method. When these parameters were included in a Cox proportional regression hazards model, PR (P = 0.01), Scarff-Bloom histological grading (P = 0.02), axillary clearance (P = 0.04) were significant; however, in the same model, taking into account the axillary lymph node histological status, IOD was

  9. Prognostic Value of Microvascular Density in Dukes A and B (T1–T4, N0, M0) Colorectal Carcinomas

    PubMed Central

    Uribarrena A, Rafael; Ortego, Javier; Fuentes, Javier; Raventós, Nuria; Parra, Pilar; Uribarrena E, Rafael

    2009-01-01

    Background. Aproximatelly 30% of patients operated on for colorectal cancer (CRC), with an expectedly favourable prognosis (Dukes A-B/T1–T4, N0, M0) suffer recurrence and/or die. Method. In order to determine if tumor microvascular density (MVD) is a prognostic factor in CRC, samples from tumors of 104 Dukes A-B CRC patients were retrospectively studied. Immunohistochemistry was performed for anti-CD34 antibody to visualize tumor vascularisation. MVD was expressed as the total number of vessels and as the percentage of microvascular area. We calculated MVD with a morphometry program and performed descriptive, bivariate, and survival statistics. Results. The mean number of vessels was 37.37/200x field, and the mean vascular area was the 3.972%. 30% of the patients with < 37 vessels/field, and 21% of the patients with > 37 vessels/field, experienced recurrence/death. The 35% of patients with < 4% of vascular area died following recurrence, compared with 14% of patients with ≥4% of vascular area. These differences in % of vascular area were statistically significant. Conclusion. MVD expressed as the total number of vessels had no a statistically significant influence on the evolution of CRC. However, neoplasias with a greater % of vascular were associated to a better outcome. PMID:19902004

  10. Myocardial fibrosis imaging based on T1-mapping and extracellular volume fraction (ECV) measurement in muscular dystrophy patients: diagnostic value compared with conventional late gadolinium enhancement (LGE) imaging.

    PubMed

    Florian, Anca; Ludwig, Anna; Rösch, Sabine; Yildiz, Handan; Sechtem, Udo; Yilmaz, Ali

    2014-09-01

    Cardiac involvement with progressive myocardial fibrosis leading to dilated cardiomyopathy is a major cause of death in muscular dystrophy patients. Extracellular volume fraction (ECV) measurement based on T1-mapping pre- and post-contrast promises the detection of early 'diffuse' myocardial fibrosis that cannot be depicted by conventional contrast-imaging based on late gadolinium enhancement (LGE). With this study, we evaluated the presence of diffuse myocardial fibrosis in regions of 'normal' (LGE-negative) and 'diseased' (LGE-positive) appearing myocardium as well as its relation to the extent of left ventricular (LV) dysfunction and the occurrence of arrhythmias in Becker muscular dystrophy (BMD) patients. Twenty-seven BMD patients (35 ± 12 years) and 17 matched male healthy controls (33 ± 8 years) underwent cardiovascular magnetic resonance (CMR) studies including ECV measurement and LGE-imaging. Ambulatory monitoring of arrhythmic events was performed by means of an external event loop recorder. Twenty BMD patients (74%) demonstrated cardiac involvement as detected by typical inferolateral presence of LGE. Twelve patients (44%) had an impaired LV ejection fraction-all being LGE-positive. Global myocardial ECV was significantly higher in the BMD group (29 ± 6%) compared with the control group (24 ± 2%, P = 0.001). Patients with cardiac involvement demonstrated higher global ECV (31 ± 6%) as well as significantly increased regional ECV not only in LGE-positive segments (34 ± 6%), but also in LGE-negative segments (28 ± 6%) compared with BMD patients without cardiac involvement and to controls, respectively (24 ± 3 and 24 ± 2%, P = 0.005). Global ECV in patients with cardiac involvement substantially correlated to LV ejection fraction (r = -0.629, P = 0.003) and to the number of LGE-positive segments (r = 0.783, P < 0.001). On univariable analysis, global ECV-but not the categorical presence of LGE per se--was significantly associated with arrhythmic

  11. Synthesis, determination of p Ka values and GIAO NMR calculations of some new 3-alkyl-4-( p-methoxybenzoylamino)-4,5-dihydro-1 H-1,2,4-triazol-5-ones

    NASA Astrophysics Data System (ADS)

    Yüksek, Haydar; Alkan, Muzaffer; Bahçeci, Şule; Cakmak, Ismail; Ocak, Zafer; Baykara, Haci; Aktaş, Ozlem; Ağyel, Elif

    2008-02-01

    3-Alkyl-4-amino-4,5-dihydro-1 H-1,2,4-triazol-5-ones ( 2) reacted with p-methoxybenzoyl chloride to afford the corresponding 3-alkyl-4-( p-methoxybenzoylamino)-4,5-dihydro-1 H-1,2,4-triazol-5-ones ( 3). Five newly synthesized compounds have been characterized by elemental analyses, IR, 1H NMR, 13C NMR and UV spectral data. The newly synthesized compounds 3 were titrated potentiometrically with tetrabutylammonium hydroxide in four non-aqueous solvents such as acetonitrile, isopropyl alcohol, tert-butyl alcohol and N, N-dimethylformamide, and the half-neutralization potential values and the corresponding p Ka values were determined for all cases. Thus, the effects of solvents and molecular structure upon acidity were investigated. In addition, isotropic 1H and 13C nuclear magnetic shielding constants of compounds 3 were obtained by the gauge-including-atomic-orbital (GIAO) method at the B3LYP density functional level. The geometry of each compound has been optimized using the 6-311G basis set. Theoretical values were compared to the experimental data.

  12. Both water source and atmospheric water impact leaf wax n-alkane 2H/1H values of hydroponically grown angiosperm trees

    NASA Astrophysics Data System (ADS)

    Tipple, B. J.; Berke, M. A.; Hambach, B.; Roden, J. S.; Ehleringer, J. R.

    2013-12-01

    The extent to which both water source and leaf water 2H-enrichment affect the δ2H values of terrestrial plant leaf waxes is an area of active research as ecologists seek a mechanistic understanding of the environmental determinants of leaf wax isotope values before applying δ2H values of leaf waxes to reconstruct past hydrologic conditions. To elucidate the effects of both water source and atmospheric water vapor on δ2H values of leaf waxes for broad-leaved angiosperms, we analyzed hydrogen isotope ratios of high-molecular weight n-alkanes from two tree species that were grown throughout the spring and summer (five months) in a hydroponic system under controlled atmospheric conditions. Here, 12 subpopulations each of Populus fremontii and Betula occidentalis saplings were grown under one of six source different waters ranging in hydrogen isotope ratio values from -120 to +180 ‰ and under either 40 % or 75 % relative humidity conditions. We found n-alkane δ2H values of both species were linearly related to source water δ2H values with differences in slope associated with differing atmospheric humidity. A Craig-Gordon model was used to predict the δ2H values of leaf water and, by extension, n-alkane δ2H values under the range of growth conditions. The modeled leaf water values were found to be linearly related to observed n-alkane δ2H values with a statistically indistinguishable slope between the high and low humidity treatments. These leaf wax observations support a constant biosynthetic fractionation factor between evaporatively-enriched leaf water and n-alkanes for each species. However, we found the calculated biosynthetic fractionation between modeled leaf-water and n-alkane to be different between the two species. We submit that these dissimilarities were due to model inputs and not differences in the specific-species biochemistry. Nonetheless, these results are significant as they indicated that the δ2H value of atmospheric water vapor and

  13. T-1 Training Area

    ScienceCinema

    None

    2016-07-12

    Another valuable homeland security asset at the NNSS is the T-1 training area, which covers more than 10 acres and includes more than 20 separate training venues. Local, County, and State first responders who train here encounter a variety of realistic disaster scenarios. A crashed 737 airliner lying in pieces across the desert, a helicopter and other small aircraft, trucks, buses, and derailed train cars are all part of the mock incident scene. After formal classroom education, first responders are trained to take immediate decisive action to prevent or mitigate the use of radiological or nuclear devices by terrorists. The Counterterrorism Operations Support Center for Radiological Nuclear Training conducts the courses and exercises providing first responders from across the nation with the tools they need to protect their communities. All of these elements provide a training experience that cannot be duplicated anywhere else in the country.

  14. T-1 Training Area

    SciTech Connect

    2014-11-07

    Another valuable homeland security asset at the NNSS is the T-1 training area, which covers more than 10 acres and includes more than 20 separate training venues. Local, County, and State first responders who train here encounter a variety of realistic disaster scenarios. A crashed 737 airliner lying in pieces across the desert, a helicopter and other small aircraft, trucks, buses, and derailed train cars are all part of the mock incident scene. After formal classroom education, first responders are trained to take immediate decisive action to prevent or mitigate the use of radiological or nuclear devices by terrorists. The Counterterrorism Operations Support Center for Radiological Nuclear Training conducts the courses and exercises providing first responders from across the nation with the tools they need to protect their communities. All of these elements provide a training experience that cannot be duplicated anywhere else in the country.

  15. Direct calculation of (1)H(2)O T(1) NMRD profiles and EPR lineshapes for the electron spin quantum numbers S = 1, 3/2, 2, 5/2, 3, 7/2, based on the stochastic Liouville equation combined with Brownian dynamics simulation.

    PubMed

    Aman, Ken; Westlund, Per-Olof

    2007-02-14

    Direct calculation of electron spin relaxation and EPR lineshapes, based on Brownian dynamics simulation techniques and the stochastic Liouville equation approach (SLE-L) [Mol. Phys., 2004, 102, 1085-1093], is here generalized to high spin systems with spin quantum number S = 3/2, 2, 5/2, 3 and 7/2. A direct calculation method is demonstrated for electron spin-spin and spin-lattice relaxation, S-, X- and Q-band EPR-lineshapes and paramagnetic enhanced water proton T(1)- NMRD profiles. The main relaxation mechanism for the electron spin system is a stochastic second rank zero field splitting (ZFS). Brownian dynamics simulation techniques are used in describing a fluctuating ZFS interaction which comprises two parts namely the "permanent" part which is modulated by isotropic reorientation diffusion, and the transient part which is modulated by fast local distortion, which is also modelled by the isotropic rotation diffusion model. The SLE-L approach present is applicable both in the perturbation (Redfield) regime as well as outside the perturbation regime, in the so called slow motion regime.

  16. NMR T1 relaxation time measurements and calculations with translational and rotational components for liquid electrolytes containing LiBF4 and propylene carbonate

    NASA Astrophysics Data System (ADS)

    Richardson, P. M.; Voice, A. M.; Ward, I. M.

    2013-12-01

    Longitudinal relaxation (T1) measurements of 19F, 7Li, and 1H in propylene carbonate/LiBF4 liquid electrolytes are reported. Comparison of T1 values with those for the transverse relaxation time (T2) confirm that the measurements are in the high temperature (low correlation time) limit of the T1 minimum. Using data from pulsed field gradient measurements of self-diffusion coefficients and measurements of solution viscosity measured elsewhere, it is concluded that although in general there are contributions to T1 from both translational and rotational motions. For the lithium ions, this is mainly translational, and for the fluorine ions mainly rotational.

  17. NMR T1 relaxation time measurements and calculations with translational and rotational components for liquid electrolytes containing LiBF4 and propylene carbonate.

    PubMed

    Richardson, P M; Voice, A M; Ward, I M

    2013-12-07

    Longitudinal relaxation (T1) measurements of (19)F, (7)Li, and (1)H in propylene carbonate/LiBF4 liquid electrolytes are reported. Comparison of T1 values with those for the transverse relaxation time (T2) confirm that the measurements are in the high temperature (low correlation time) limit of the T1 minimum. Using data from pulsed field gradient measurements of self-diffusion coefficients and measurements of solution viscosity measured elsewhere, it is concluded that although in general there are contributions to T1 from both translational and rotational motions. For the lithium ions, this is mainly translational, and for the fluorine ions mainly rotational.

  18. Bone marrow edema-like lesions (BMELs) are associated with higher T1ρ and T2 values of cartilage in anterior cruciate ligament (ACL)-reconstructed knees: a longitudinal study

    PubMed Central

    Gong, Jingshan; Pedoia, Valentina; Facchetti, Luca; Link, Thomas M.; Ma, C. Benjamin

    2016-01-01

    Background To evaluate the longitudinal changes of bone marrow edema-like lesions (BMELs) in patients after anterior cruciate ligament (ACL) reconstruction and to investigate the effect of BMELs on cartilage matrix composition changes measured using MR T1ρ and T2 mapping. Methods Patients with acute ACL tear were enrolled in a prospective study. MR imaging was performed at baseline (before surgeries) and at 6-month, 1-year and 2-year after ACL reconstruction. MR imaging included sagittal high-resolution, 3D fast spin-echo (CUBE) sequences for BMEL evaluation, and 3D T1ρ mapping and T2 mapping for cartilage assessment. BMELs were assessed using whole-organ magnetic resonance imaging score (WORMS), and the volume of BMELs was measured by a semi-automatic method. Generalized estimating equation (GEE) was used to explore association between BMELs at baseline and cartilage changes during follow-up. Results Fifty four patients were included in the present study and 39 patients had completed 2-year follow-up. BMELs were noted in 42 injured knees (77.8%) with 105 lesions and in 7 contralateral knees (13.0%) with 9 lesions (χ2=45.763, P<0.001) at the baseline. The WORMS and volume of BMELs of the injured knees were 2.36±0.65 and 386.98±382.54 mm3 (r=0.681, P<0.001), respectively. 87 BMELs were found at baseline in 34 patients (87.2%) of the 39 patients who had completed 2 years follow-up. During the follow-up, 18 (20.7%), 12 (13.8%), and 5 (5.7%) baseline lesions were still seen at 6-month, 1-year and 2-year, respectively. The changes of BMELs prevalence regarding bone compartments over time points were statistically significant (χ2=163.660, P<0.001). Except T2 value at 6 months, T1ρ and T2 values of cartilage overlying baseline BMELs in the injured knees were higher than that of anatomically matched cartilage in the contralateral knees at baseline and each follow-up time-point. In the injured knees, GEE analysis showed that baseline BMELs were significantly

  19. Determination of pKa values of tenoxicam from 1H NMR chemical shifts and of oxicams from electrophoretic mobilities (CZE) with the aid of programs SQUAD and HYPNMR.

    PubMed

    Rodríguez-Barrientos, Damaris; Rojas-Hernández, Alberto; Gutiérrez, Atilano; Moya-Hernández, Rosario; Gómez-Balderas, Rodolfo; Ramírez-Silva, María Teresa

    2009-12-15

    In this work it is explained, by the first time, the application of programs SQUAD and HYPNMR to refine equilibrium constant values through the fit of electrophoretic mobilities determined by capillary zone electrophoresis experiments, due to the mathematical isomorphism of UV-vis absorptivity coefficients, NMR chemical shifts and electrophoretic mobilities as a function of pH. Then, the pK(a) values of tenoxicam in H(2)O/DMSO 1:4 (v/v) have been obtained from (1)H NMR chemical shifts, as well as of oxicams in aqueous solution from electrophoretic mobilities determined by CZE, at 25 degrees C. These values are in very good agreement with those reported by spectrophotometric and potentiometric measurements.

  20. U1h Superstructure

    SciTech Connect

    Glen Sykes

    2000-11-01

    The U1H Shaft Project is a design build subcontract to supply the U. S. Department of Energy (DOE) a 1,045 ft. deep, 20 ft. diameter, concrete lined shaft for unspecified purposes. The subcontract awarded to Atkinson Construction by Bechtel Nevada to design and construct the shaft for the DOE has been split into phases with portions of the work being released as dictated by available funding. The first portion released included the design for the shaft, permanent hoist, headframe, and collar arrangement. The second release consisted of constructing the shaft collar to a depth of 110 ft., the service entry, utility trenches, and installation of the temporary sinking plant. The temporary sinking plant included the installation of the sinking headframe, the sinking hoist, two deck winches, the shaft form, the sinking work deck, and temporary utilities required to sink the shaft. Both the design and collar construction were completed on schedule. The third release consisted of excavating and lining the shaft to the station depth of approximately 950 feet. Work is currently proceeding on this production sinking phase. At a depth of approximately 600 feet, Atkinson has surpassed production expectation and is more than 3 months ahead of schedule. Atkinson has employed the use of a Bobcat 331 excavator as the primary means of excavation. the shaft is being excavated entirely in an alluvial deposit with varying degrees of calcium carbonate cementation. Several more work packages are expected to be released in the near future. The remaining work packages include, construction of the shaft station a depth of 975 ft. and construction of the shaft sump to a depth of 1,045 ft., installation of the loading pocket and station steel and equipment, installation of the shaft steel and guides, installation of the shaft utilities, and installation of the permanent headframe, hoist, collar utilities, and facilities.

  1. The magnetic field dependence of water T1 in tissues.

    PubMed

    Diakova, Galina; Korb, Jean-Pierre; Bryant, Robert G

    2012-07-01

    The magnetic field dependence of the composite (1)H(2)O nuclear magnetic resonance signal T(1) was measured for excised samples of rat liver, muscle, and kidney over the field range from 0.7 to 7 T (35-300 MHz) with a nuclear magnetic resonance spectrometer using sample-shuttle methods. Based on extensive measurements on simpler component systems, the magnetic field dependence of T(1) of all tissues studied are readily fitted at Larmor frequencies above 1 MHz with a simple relaxation equation consisting of three contributions: a power law, A*ω(-0.60) related to the interaction of water with long-lived-protein binding sites, a logarithmic term B*τ(d) *log(1+1/(ωτ(d))(2)) related to water diffusion at macromolecular interfacial regions, and a constant term associated with the high frequency limit of water-spin-lattice relaxation. The parameters A and B include the concentration and surface area dependences respectively. The logarithmic diffusion term becomes significant at high magnetic fields and is consistent with rapid translational dynamics at macromolecular surfaces. The data are fitted well with translational correlation times of approximately 15 ps for human brain white matter, but with a B value three times larger than gray matter tissues. This analysis suggests that the water-surface translational correlation time is approximately three times longer than in gray matter. Copyright © 2011 Wiley Periodicals, Inc.

  2. Low-contrast focal lesion detectability phantom for 1H MR imaging.

    PubMed

    Madsen, E L; Blechinger, J C; Frank, G R

    1991-01-01

    A phantom made from tissue-mimicking materials is reported for testing 1H MRI systems regarding their ability to detect small low-contrast focal lesions and to delineate the boundaries of larger lesions. Two sets of seven spherical simulated lesions with diameters of 2, 3, 4, 5, 6.3, 7.9, and 9.5 mm have T1 and T2 values somewhat higher than the corresponding values in the surrounding simulated normal tissue. Relaxometer determinations of T1 and T2 for the simulated normal tissue yielded 955 and 106 ms, respectively, at 22 degrees C and 1 T. The corresponding values in set #1 of the simulated lesions were 1017 and 175 ms and in set #2 were 1002 and 127 ms. These T1 and T2 values are similar to those for brain and brain lesions but are too high to represent soft tissue such as liver and muscle. The centers of the 14 lesions are coplanar, and eight alignment devices surround them facilitating superposition of the scan plane and the plane containing the centers of the lesions. Illustrative images made with a 1.5-T system are shown. All simulated lesions are detectable in T2-weighted head coil images. Corresponding T1-weighted images are also shown, the 2- and 3-mm lesions of set #2 and the 2-mm lesion of set #1 not being detectable. The phantoms could be useful for performance or acceptance testing and perhaps for quality assurance testing.

  3. [Prognostic value of quantitative DNA analysis, expressed in integrated optical density, in a series of 415 T1-T2, N0N1, M0 UICC breast cancers].

    PubMed

    Bolla, M; Seigneurin, D; Winckel, P; Marron-Charrière, J; Panh, M H; Pasquier, D; Chédin, M; Payan, R; Merlin, F; Venditti, V

    1996-09-01

    From June 1982 to December 1992, 415 patients less than 75 years of age, without any previous or synchronous carcinoma, suffering from an invasive breast cancer classified as T1 (52.8%), T2 (47.2%), NO (65.1%) N1(34.9%), MO according to clinical TNM staging, were enrolled in this study. The median age was 53 (28-75), and 58.8% of the patients were menopaused; 85.3% underwent a breast conservative procedure and 14.7% a modified radical mastectomy followed by postoperative irradiation. Histological axillary lymph node status, Scarff-Bloom grade and/or cytological grade, estradiol receptor content, were used to set up medical adjuvant treatment: hormonotherapy (52%) or chemotherapy (18.8%). Imprints were taken from the macroscopically visible lesion at the time of surgery, and a Feulgen staining was done on air dried smears to be analyzed using the Samba 200 cell image processor (Alcatel TITN, France). Five parameters were systematically assessed: proliferation index, DNA histogram, integrated optical density, DNA malignancy grade, and policy balance. With a median follow-up of 36 months (0-105), proliferation index (P = 0.0008), DNA histogram (P = 0.0017), integrated optical density (P = 0.018), DNA malignancy grade (P = 0.017) have a significant prognostic value on disease free survival estimated by the Kaplan-Meir method. When these parameters were included in a Cox proportional regression hazards model, Scarff-Bloom histological grading (P = 0.002), positives nodes (P = 0.02), optical integrated density (P = 0.045) were significant. Such results need to be updated with a longer follow-up, but they suggest that the mean DNA content, as measured by the integrated optical density (IOD), has to be considered when deciding on medical adjuvant treatment with respect to patients with a negative axillary clearance.

  4. Hydrogen storage in fragmented carbon nanotubes: 1H NMR

    NASA Astrophysics Data System (ADS)

    Schmid, M.; Krämer, S.; Mehring, M.; Roth, S.; Haluska, M.; Bernier, P.

    2001-11-01

    We report 1H Nuclear Magnetic Resonance (NMR) studies on single walled carbon nanotubes, ball milled under hydrogen atmosphere. We have measured field and temperature dependence of proton spectra, linewidth and spin-lattice relaxation rates (T1-1). The results are interpreted by applying a quantitative model for 1H linewidth and spin-lattice relaxation rates induced by remanent dilute paramagnetic impurities. By using a calibration method with a reference sample we were able to quantify the hydrogen content.

  5. Brain Metabolites B1–Corrected Proton T1 Mapping in the Rhesus Macaque at 3 T

    PubMed Central

    Liu, Songtao; Fleysher, Roman; Fleysher, Lazar; Joo, Chan-Gyu; Ratai, Eva-Maria; González, R. Gilberto; Gonen, Oded

    2010-01-01

    The accuracy of metabolic quantification in MR spectroscopy (MRS) is limited by the unknown radio-frequency field (B1) and longitudinal relaxation time (T1). To address both issues in proton (1H) MRS we obtained B1-corrected T1 maps of N-acetylaspartate (NAA), choline (Cho) and creatine (Cr) in five healthy rhesus macaques at 3 T. For efficient use of the 4 hour experiment, we used a new three-point protocol that optimizes the precision of T1 in 3D 1H-MRS localization for extensive, ~30%, brain coverage at (0.6×0.6×0.5 cm)3=180 μL spatial resolution. The resulting mean±standard error (SEM) T1s in 700 voxels were: NAA=1232±44, Cr=1238±23 and Cho=1107±56 ms. Their histograms from all 140 voxels in each animal were similar in position and shape - characterized by SEMs of the full width at half maximum divided by their means, of better than 8%. Regional gray matter NAA, Cho and Cr T1s: 1333±43, 1265±52 and 1131±28 ms were 5–10% longer than white matter: 1188±34, 1201±24 and 1082±50 ms (statistically significant for the NAA only), all within 10% of the corresponding published values in the human brain. PMID:20373387

  6. Deep gray matter iron measurement in patients with liver cirrhosis using quantitative susceptibility mapping: Relationship with pallidal T1 hyperintensity.

    PubMed

    Lee, Song; Nam, Yoonho; Jang, Jinhee; Na, Gun Hyung; Kim, Dong Goo; Shin, Na-Young; Choi, Hyun Seok; Jung, So-Lyung; Ahn, Kook-Jin; Kim, Bum-Soo

    2017-08-17

    The liver is a central organ for the metabolism of iron and manganese and the places where those metals are commonly deposited overlap in the brain. To elucidate the relationship between pallidal T1 hyperintensity and iron deposition in the deep gray matter of liver cirrhosis patients using quantitative susceptibility mapping (QSM). Retrospective case-control study SUBJECTS: In all, 38 consecutive liver cirrhosis patients who received brain magnetic resonance imaging (MRI) as pretransplant evaluation. QSM was reconstructed from 3D multi- or single-echo phase images at 3T. T1 -weighted images were used for the assessment of pallidal hyperintensity and pallidal index (PI). Patients were divided into two groups according to the presence of pallidal hyperintensity by consensus of two radiologists. Susceptibility values were acquired for five deep gray matter structures. QSM measures were compared between two groups using the t-test. We also calculated Pearson correlations between QSM measures and PI. In all, 26 patients showed pallidal hyperintensity (T1 h group) and 12 did not (T1 n group). The susceptibility of the globus pallidus (GP) in the T1 h group (120.6 ± 38.1 ppb) was significantly lower than that in the T1 n group (150.0 ± 35.2, P = 0.030). The susceptibility of the dentate nucleus (DN) in the T1 h group (88.1 ± 31.0) was significantly lower than that in the T1 n group (125.6 ± 30.6, P = 0.001). Negative correlation between the susceptibility of GP (r = -0.37, P = 0.022) and the PI, and between DN (r = -0.43, P < 0.001) and the PI was found. Liver cirrhosis patients with pallidal T1 hyperintensity had lower susceptibility values in the GP and DN than those without it. This suggests a possible interaction between iron and manganese in the brains of liver cirrhosis patients. 3 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2017. © 2017 International Society for Magnetic Resonance in Medicine.

  7. The diagnostic value of 99TcM-2-(2-methyl-5-nitro-1H-imidazol-1-yl) ethyl dihydrogen phosphate hypoxia imaging and its evaluation performance for radiotherapy efficacy in non-small-cell lung cancer

    PubMed Central

    Yang, Yongkun; Han, Gaohua; Xu, Wansong

    2016-01-01

    Background and aim This study was designated to assess the diagnostic value of 99TcM-2-(2-methyl-5-nitro-1H-imidazol-1-yl) ethyl dihydrogen phosphate (99TcM-MNLS) hypoxia imaging and its evaluation performance for radiotherapy efficacy in patients with non-small-cell lung cancer (NSCLC). Patients and methods A total of 61 patients with NSCLC were selected for this study. All patients were injected with 99TcM-MNLS within 1 week prior to radiotherapy and they were injected with 99TcM-MNLS again 3 months after radiotherapy. Qualitative analysis along with semiquantitative analysis results were obtained from hypoxia imaging. Meanwhile, the effect of radiotherapy on patients with NSCLC was evaluated based on the solid tumor curative effect evaluation standard. Finally, SPSS 19.0 statistical software was implemented for statistical analysis. Results There was no significant difference in age or sex between the NSCLC patient group and benign patient group (P>0.05). 99TcM-MNLS was selectively concentrated in tumor tissues with a clear imaging in 24 hours. Results from both qualitative analysis and semiquantitative analysis indicated that the sensitivity and specificity of 99TcM-MNLS hypoxia imaging in diagnosing NSCLC were 93.8% and 84.6% and 72.9% and 100%, respectively. Moreover, the receiver operating characteristic curve provided evidence that 99TcM-MNLS hypoxia imaging was a powerful diagnostic tool in distinguishing malignant lung cancer from benign lesions. As suggested by 24-hour imaging, the tumor-to-normal ratio of patients in the 99TcM-MNLS high-intake group and low-intake group had a decline of 24.7% and 14.4% after radiotherapy, respectively. The decline in the tumor-to-normal ratio between the two dosage groups was significantly different (P<0.05). Conclusion 99TcM-MNLS hypoxia imaging had reliable values in both diagnosing NSCLC and evaluating therapeutic effects of radiotherapy on patients with NSCLC. PMID:27799797

  8. The diagnostic value of (99)Tc(M)-2-(2-methyl-5-nitro-1H-imidazol-1-yl) ethyl dihydrogen phosphate hypoxia imaging and its evaluation performance for radiotherapy efficacy in non-small-cell lung cancer.

    PubMed

    Yang, Yongkun; Han, Gaohua; Xu, Wansong

    2016-01-01

    This study was designated to assess the diagnostic value of (99)Tc(M)-2-(2-methyl-5-nitro-1H-imidazol-1-yl) ethyl dihydrogen phosphate ((99)Tc(M)-MNLS) hypoxia imaging and its evaluation performance for radiotherapy efficacy in patients with non-small-cell lung cancer (NSCLC). A total of 61 patients with NSCLC were selected for this study. All patients were injected with (99)Tc(M)-MNLS within 1 week prior to radiotherapy and they were injected with (99)Tc(M)-MNLS again 3 months after radiotherapy. Qualitative analysis along with semiquantitative analysis results were obtained from hypoxia imaging. Meanwhile, the effect of radiotherapy on patients with NSCLC was evaluated based on the solid tumor curative effect evaluation standard. Finally, SPSS 19.0 statistical software was implemented for statistical analysis. There was no significant difference in age or sex between the NSCLC patient group and benign patient group (P>0.05). (99)Tc(M)-MNLS was selectively concentrated in tumor tissues with a clear imaging in 24 hours. Results from both qualitative analysis and semiquantitative analysis indicated that the sensitivity and specificity of (99)Tc(M)-MNLS hypoxia imaging in diagnosing NSCLC were 93.8% and 84.6% and 72.9% and 100%, respectively. Moreover, the receiver operating characteristic curve provided evidence that (99)Tc(M)-MNLS hypoxia imaging was a powerful diagnostic tool in distinguishing malignant lung cancer from benign lesions. As suggested by 24-hour imaging, the tumor-to-normal ratio of patients in the (99)Tc(M)-MNLS high-intake group and low-intake group had a decline of 24.7% and 14.4% after radiotherapy, respectively. The decline in the tumor-to-normal ratio between the two dosage groups was significantly different (P<0.05). (99)Tc(M)-MNLS hypoxia imaging had reliable values in both diagnosing NSCLC and evaluating therapeutic effects of radiotherapy on patients with NSCLC.

  9. MOLLI and AIR T1 mapping pulse sequences yield different myocardial T1 and ECV measurements.

    PubMed

    Hong, KyungPyo; Kim, Daniel

    2014-11-01

    Both post-contrast myocardial T1 and extracellular volume (ECV) have been reported to be associated with diffuse interstitial fibrosis. Recently, the cardiovascular magnetic resonance (CMR) field is recognizing that post-contrast myocardial T1 is sensitive to several confounders and migrating towards ECV as a measure of collagen volume fraction. Several recent studies using widely available Modified Look-Locker Inversion-recovery (MOLLI) have reported ECV cutoff values to distinguish between normal and diseased myocardium. It is unclear if these cutoff values are translatable to different T1 mapping pulse sequences such as arrhythmia-insensitive-rapid (AIR) cardiac T1 mapping, which was recently developed to rapidly image patients with cardiac rhythm disorders. We sought to evaluate, in well-controlled canine and pig experiments, the relative accuracy and precision, as well as intra- and inter-observer variability in data analysis, of ECV measured with AIR as compared with MOLLI. In 16 dogs, as expected, the mean T1 was significantly different (p < 0.001) between MOLLI (891 ± 373 ms) and AIR (1071 ± 503 ms), but, surprisingly, the mean ECV between MOLLI (21.8 ± 2.1%) and AIR (19.6 ± 2.4%) was also significantly different (p < 0.001). Both intra- and inter-observer agreements in T1 calculations were higher for MOLLI than AIR, but intra- and inter-observer agreements in ECV calculations were similar between MOLLI and AIR. In six pigs, the coefficient of repeatability (CR), as defined by the Bland-Altman analysis, in T1 calculation was considerably lower for MOLLI (32.5 ms) than AIR (82.3 ms), and the CR in ECV calculation was also lower for MOLLI (1.8%) than AIR (4.5%). In conclusion, this study shows that MOLLI and AIR yield significantly different T1 and ECV values in large animals and that MOLLI yields higher precision than AIR. Findings from this study suggest that CMR researchers must consider the specific pulse sequence when translating published ECV cutoff

  10. MOLLI and AIR T1 Mapping Pulse Sequences Yield Different Myocardial T1 and ECV Measurements

    PubMed Central

    Hong, KyungPyo; Kim, Daniel

    2014-01-01

    Both post-contrast myocardial T1 and extracellular volume (ECV) have been reported to be associated with diffuse interstitial fibrosis. Recently, the cardiovascular magnetic resonance (CMR) field is recognizing that post-contrast myocardial T1 is sensitive to several confounders and migrating towards ECV as a measure of collagen volume fraction. Several recent studies using widely available Modified Look-Locker Inversion-recovery (MOLLI) have reported ECV cutoff values to distinguish between normal and diseased myocardium. It is unclear if these cutoff values are translatable to different T1 mapping pulse sequences such as arrhythmia-insensitive-rapid (AIR) cardiac T1 mapping, which was recently developed to rapidly image patients with cardiac rhythm disorders. We sought to evaluate, in well-controlled canine and pig experiments, the relative accuracy and precision, as well as intra- and inter-observer variability in data analysis, of ECV measured with AIR as compared with MOLLI. In 16 dogs, as expected, mean T1 was significantly different (p < 0.001) between MOLLI (891±373 ms) and AIR (1071±503 ms), but, surprisingly, mean ECV between MOLLI (21.8±2.1%) and AIR (19.6±2.4%) was also significantly different (p < 0.001). Both intra- and inter-observer agreements in T1 calculations were higher for MOLLI than AIR, but intra- and inter-observer agreements in ECV calculations were similar between MOLLI and AIR. In 6 pigs, coefficient of repeatability (CR), as defined by Bland-Altman analysis, of T1 was considerably lower for MOLLI (32.5 ms) than AIR (82.3 ms), and CR of ECV was also lower for MOLLI (1.8%) than AIR (4.5%). In conclusion, this study shows that MOLLI and AIR yield significantly different T1 and ECV values in large animals and that MOLLI yields higher precision than AIR. Findings from this study suggest that CMR researchers must consider the specific pulse sequence when translating published ECV cutoff values into their own studies. PMID:25323070

  11. Large scale human metabolic phenotyping and molecular epidemiological studies via 1H NMR spectroscopy of urine: Investigation of borate preservation

    PubMed Central

    Smith, Leon M.; Maher, Anthony D.; Want, Elizabeth J.; Elliott, Paul; Stamler, Jeremiah; Hawkes, Geoffrey E.; Holmes, Elaine; Lindon, John C.; Nicholson, Jeremy K.

    2009-01-01

    Borate is an antibacterial preservative widely used in clinical and large scale epidemiological studies involving urine sample analysis. Since it readily forms covalent adducts and reversible complexes with hydroxyl and carboxylate groups, the effects of borate preservation in 1H NMR spectroscopy-based metabolic profiling of human urine samples have been assessed. Effects of various concentrations of borate (range 0–30 mM) on 1H NMR spectra of urine were observed at sequential time points over a 12 month period. Consistent with known borate chemistry, the principal alterations in the 1H resonance metabolite patterns were observed for compounds such as mannitol, citrate and α-hydroxyisobutyrate and confirmed by ESI-MS analysis. These included line-broadening, T1 and T2 relaxation and chemical shift changes consistent with complex formation and chemical exchange processes. To further investigate complexation behavior in the urinary metabolite profiles, a new tool for visualization of multi-component relaxation variations in which the spectra were color-coded according to the T1 and T2 proton relaxation times respectively (T1 or T2 Ordered Projection SpectroscopY, TOPSY) was also developed and applied. Addition of borate caused a general decrease in 1H T1 values consistent with non-specific effects such as solution viscosity changes. Minor changes in proton T2 relaxation rates were observed for the most strongly complexing metabolites. From a molecular phenotyping and epidemiologic viewpoint, typical interpersonal biological variation was shown to be vastly greater than any variation introduced by the borate complexation which had a negligible effect on the metabolic mapping and classification of samples. Whilst caution is indicated in the assignment of biomarker signals where metabolites have diol groupings or where there are adjacent hydroxyl and carboxylate functions, it is concluded that borate preservation is “fit-forpurpose” for 1H NMR

  12. A subzero 1H NMR relaxation investigation of water dynamics in tomato pericarp.

    PubMed

    Foucat, Loïc; Lahaye, Marc

    2014-09-01

    (1)H NMR relaxation times (T1 and T2) were measured at low field (0.47 T) in pericarp tissues of three tomato genotypes (Ferum, LA0147 and Levovil) at subzero temperature (-20 °C) and two ripening stages (mature green and red). The unfrozen water dynamics was characterised by two T1 and three T2 components. The relaxation time values and their associated relative populations allowed differentiating the ripening stage of only LA0147 and Levovil lines. But the three genotypes were unequivocally discriminated at the red ripe stage. The unfrozen water distribution was discussed in terms of specific interactions, especially with sugars, in relation with their osmoprotectant effects.

  13. 1H and 2H NMR spin-lattice relaxation probing water: PEG molecular dynamics in solution.

    PubMed

    Clop, Eduardo M; Perillo, María A; Chattah, Ana K

    2012-10-04

    Nuclear magnetic resonance spin-lattice relaxation times (T(1)) measurements were performed in aqueous solutions of poly(ethylene glycol) (PEG) of 6000 Da molecular mass to study the dynamical relation between PEG and water molecules at different solute concentrations. (1)H-T(1) experiments were carried on at a low magnetic field in the time domain (20 MHz) and at a high field (400 MHz) to obtain spectral resolution. Two contributing components were identified in each proton system, PEG and water, presenting values of T(1) with very different orders of magnitude. The approximate matching between the shorter (1)H-T(1) values associated with water and PEG has lead us to conclude that there exists a network of interactions (hydrogen bonds) between the solute and the solvent, which results in the presence of an ordered and dehydrated structure of PEG folded or self-assembled in equilibrium with a more flexible monomer structure. Dynamic light scattering results were consistent with the formation of PEG aggregates, showing a mean size between 40 and 100 nm.

  14. Some properties of the sum C1(h, k)

    NASA Astrophysics Data System (ADS)

    Cetin, Elif

    2017-07-01

    In [10], we have investigated properties of the sum C1(h, k). In this paper, we will give some other arithmetic properties of the sum C1(h, k). Moreover, in the light of the sum B1(h, k), which has also defined in [10], we will give specific values of the sum C1(h, k) when h + k is an odd number. Finally, we will give a relation between the sum C1(h, k) and the Hardy-Berndt sum s5(h, k) for a special case.

  15. 1H NMR relaxation of water: a probe for surfactant adsorption on kaolin.

    PubMed

    Totland, Christian; Lewis, Rhiannon T; Nerdal, Willy

    2011-11-01

    In this study, (1)H NMR is used to investigate properties of sodium dodecyl sulfate (SDS), tetradecyl trimethyl ammonium bromide (TTAB), and dodecyl trimethyl ammonium bromide (DTAB) adsorbed on kaolin by NMR T(1) and T(2) measurements of the water proton resonance. The results show that adsorbed surfactants form a barrier between sample water and the paramagnetic species present on the clay surface, thus significantly increasing the proton T(1) values of water. This effect is attributed to the amount of adsorbed surfactants and the arrangement of the surfactant aggregates. The total surface area covered by the cationic (DTAB and TTAB) and anionic (SDS) surfactants could be estimated from the water T(1) data and found to correspond to the fractions of negatively and positively charged surface area, respectively. For selected samples, the amount of paramagnetic species on the clay surface was reduced by treatment with hydrofluoric (HF) acid. For these samples, T(1) and T(2) measurements were taken in the temperature range 278-338 K, revealing detailed information on molecular mobility and nuclear exchange for the sample water that is related to surfactant behavior both on the surface and in the aqueous phase.

  16. 1H NMR study of the phase transitions of trissarcosine calcium chloride single crystals at low temperature

    NASA Astrophysics Data System (ADS)

    Lee, Kyuhong; Lee, Moohee; Lee, Kwang Sei; Lim, Ae Ran

    2005-10-01

    The 1H NMR line-width and spin lattice relaxation time T1 of TSCC single crystals were studied. Variations in the temperature dependence of the spin lattice relaxation time were observed near 65 and 130 K, indicating drastic alterations of the spin dynamics at the phase transition temperatures. The changes in the temperature dependence of T1 near 65 and 130 K correspond to phase transitions of the crystal. The anomalous decrease in T1 around 130 K is due to the critical slowing down of the soft mode. The abrupt change in relaxation time at 65 K is associated with a structural phase transition. The proton spin lattice relaxation time of this crystal also has a minimum value in the vicinity of 185 K, which is governed by the reorientation of the CH3 groups of the sarcosine molecules. From this result, we conclude that the two phase transitions at 65 and 130 K can be discerned from abrupt variations in the 1H NMR relaxation behavior, and that 1H nuclei play important roles in the phase transitions of the TSCC single crystal.

  17. Pharmacological characterisation of the GlyT-1 glycine transporter using two novel radioligands.

    PubMed

    Herdon, Hugh J; Roberts, Jennifer C; Coulton, Steve; Porter, Rod A

    2010-11-01

    Inhibitors of the glycine transporter GlyT-1 are being developed as potential treatments for schizophrenia. Here we report on the use of two novel radioligands, [(3)H]-SB-733993 and [(3)H]-GSK931145, for the characterisation of GlyT-1 in both cells and native tissue. Binding was evaluated in membranes either from HEK293 cells expressing recombinant human GlyT-1 (hGlyT-1) or from rat cerebral cortex. Specific binding of both [(3)H]-SB-733993 and [(3)H]-GSK931145 to hGlyT-1 HEK293 cell membranes and rat cerebral cortex membranes was saturable and comprised >90% of total binding. K(d) and B(max) values for the two radioligands were fairly similar, with K(d) values of 1-2 nM and B(max) values of around 7000 fmol/mg protein in hGlyT-1 membranes and 3000 fmol/mg protein in rat cortex membranes. Association of [(3)H]-SB-733993 was faster, with binding reaching equilibrium within 30 min compared with 90 min for [(3)H]-GSK931145. Dissociation was also much slower for [(3)H]-GSK931145 than for [(3)H]-SB-733993, with 50% of specific binding being dissociated by approximately 40 min and 5 min, respectively. Autoradiography studies with [(3)H]-GSK931145 showed widespread distribution of binding in rat brain, with generally higher binding in caudal compared with rostral areas. Initial studies in human frontal cortex membranes showed clear specific binding of [(3)H]-GSK931145, though with much lower density (B(max) 570 fmol/mg protein) and slightly lower affinity (K(d) 4.5 nM) compared with rat cortex. A human brain autoradiography study showed higher specific binding in cerebellum compared with frontal cortex. All GlyT-1 inhibitors tested, as well as glycine itself, competed fully for the binding of both [(3)H]-SB-733993 and [(3)H]-GSK931145 in both hGlyT-1 and rat cortex membranes. Studies on the effect of varying NaCl concentration showed that [(3)H]-SB-733993 binding was reduced by >90% in the absence of added Na(+) ions, whilst [(3)H]-GSK931145 binding was unaffected

  18. Three-dimensional ultrashort echo time cones T1ρ (3D UTE-cones-T1ρ ) imaging.

    PubMed

    Ma, Ya-Jun; Carl, Michael; Shao, Hongda; Tadros, Anthony S; Chang, Eric Y; Du, Jiang

    2017-03-20

    We report a novel three-dimensional (3D) ultrashort echo time (UTE) sequence employing Cones trajectory and T1ρ preparation (UTE-Cones-T1ρ ) for quantitative T1ρ assessment of short T2 tissues in the musculoskeletal system. A basic 3D UTE-Cones sequence was combined with a spin-locking preparation pulse for T1ρ contrast. A relatively short TR was used to decrease the scan time, which required T1 measurement and compensation using 3D UTE-Cones data acquisitions with variable TRs. Another strategy to reduce the total scan time was to acquire multiple Cones spokes (Nsp ) after each T1ρ preparation and fat saturation. Four spin-locking times (TSL = 0-20 ms) were acquired over 12 min, plus another 7 min for T1 measurement. The 3D UTE-Cones-T1ρ sequence was compared with a two-dimensional (2D) spiral-T1ρ sequence for the imaging of a spherical CuSO4 phantom and ex vivo meniscus and tendon specimens, as well as the knee and ankle joints of healthy volunteers, using a clinical 3-T scanner. The CuSO4 phantom showed a T1ρ value of 76.5 ± 1.6 ms with the 2D spiral-T1ρ sequence, as well as 85.7 ± 3.6 and 89.2 ± 1.4 ms for the 3D UTE-Cones-T1ρ sequences with Nsp of 1 and 5, respectively. The 3D UTE-Cones-T1ρ sequence provided shorter T1ρ values for the bovine meniscus sample relative to the 2D spiral-T1ρ sequence (10-12 ms versus 16 ms, respectively). The cadaveric human Achilles tendon sample could only be imaged with the 3D UTE-Cones-T1ρ sequence (T1ρ  = 4.0 ± 0.9 ms), with the 2D spiral-T1ρ sequence demonstrating near-zero signal intensity. Human studies yielded T1ρ values of 36.1 ± 2.9, 18.3 ± 3.9 and 3.1 ± 0.4 ms for articular cartilage, meniscus and the Achilles tendon, respectively. The 3D UTE-Cones-T1ρ sequence allows volumetric T1ρ measurement of short T2 tissues in vivo.

  19. A medical device-grade T1 and ECV phantom for global T1 mapping quality assurance-the T1 Mapping and ECV Standardization in cardiovascular magnetic resonance (T1MES) program.

    PubMed

    Captur, Gabriella; Gatehouse, Peter; Keenan, Kathryn E; Heslinga, Friso G; Bruehl, Ruediger; Prothmann, Marcel; Graves, Martin J; Eames, Richard J; Torlasco, Camilla; Benedetti, Giulia; Donovan, Jacqueline; Ittermann, Bernd; Boubertakh, Redha; Bathgate, Andrew; Royet, Celine; Pang, Wenjie; Nezafat, Reza; Salerno, Michael; Kellman, Peter; Moon, James C

    2016-09-22

    T1 mapping and extracellular volume (ECV) have the potential to guide patient care and serve as surrogate end-points in clinical trials, but measurements differ between cardiovascular magnetic resonance (CMR) scanners and pulse sequences. To help deliver T1 mapping to global clinical care, we developed a phantom-based quality assurance (QA) system for verification of measurement stability over time at individual sites, with further aims of generalization of results across sites, vendor systems, software versions and imaging sequences. We thus created T1MES: The T1 Mapping and ECV Standardization Program. A design collaboration consisting of a specialist MRI small-medium enterprise, clinicians, physicists and national metrology institutes was formed. A phantom was designed covering clinically relevant ranges of T1 and T2 in blood and myocardium, pre and post-contrast, for 1.5 T and 3 T. Reproducible mass manufacture was established. The device received regulatory clearance by the Food and Drug Administration (FDA) and Conformité Européene (CE) marking. The T1MES phantom is an agarose gel-based phantom using nickel chloride as the paramagnetic relaxation modifier. It was reproducibly specified and mass-produced with a rigorously repeatable process. Each phantom contains nine differently-doped agarose gel tubes embedded in a gel/beads matrix. Phantoms were free of air bubbles and susceptibility artifacts at both field strengths and T1 maps were free from off-resonance artifacts. The incorporation of high-density polyethylene beads in the main gel fill was effective at flattening the B 1 field. T1 and T2 values measured in T1MES showed coefficients of variation of 1 % or less between repeat scans indicating good short-term reproducibility. Temperature dependency experiments confirmed that over the range 15-30 °C the short-T1 tubes were more stable with temperature than the long-T1 tubes. A batch of 69 phantoms was mass-produced with random sampling of ten of

  20. Systematic T1 improvement for hyperpolarized 129xenon.

    PubMed

    Repetto, Maricel; Babcock, Earl; Blümler, Peter; Heil, Werner; Karpuk, Sergei; Tullney, Kathlynne

    2015-03-01

    The spin-lattice relaxation time T1 of hyperpolarized (HP)-(129)Xe was improved at typical storage conditions (i.e. low and homogeneous magnetic fields). Very long wall relaxation times T(1)(wall) of about 18 h were observed in uncoated, spherical GE180 glass cells of ∅=10 cm which were free of rubidium and not permanently sealed but attached to a standard glass stopcock. An "aging" process of the wall relaxation was identified by repeating measurements on the same cell. This effect could be easily removed by repeating the initial cleaning procedure. In this way, a constant wall relaxation was ensured. The Xe nuclear spin-relaxation rate 1/T1(Xe-Xe) due to van der Waals molecules was investigated too, by admixing three different buffer gases (N(2), SF(6) and CO(2)). Especially CO(2) exhibited an unexpected high efficiency (r) in shortening the lifetime of the Xe-Xe dimers and hence prolonging the total T1 relaxation even further. These measurements also yielded an improved accuracy for the van der Waals relaxation for pure Xe (with 85% (129)Xe) of T(1)(Xe-Xe)=(4.6±0.1)h. Repeating the measurements with HP (129)Xe in natural abundance in mixtures with SF6, a strong dependence of T(1)(Xe-Xe) and r on the isotopic enrichment was observed, uncovering a shorter T(1)(Xe-Xe) relaxation for the (129)Xe in natural composition as compared to the 85% isotopically enriched gas.

  1. Design of a multimodal ((1)H/(23)Na MR/CT) anthropomorphic thorax phantom.

    PubMed

    Neumann, Wiebke; Lietzmann, Florian; Schad, Lothar R; Zöllner, Frank G

    2017-06-01

    This work proposes a modular, anthropomorphic MR and CT thorax phantom that enables the comparison of experimental studies for quantitative evaluation of deformable, multimodal image registration algorithms and realistic multi-nuclear MR imaging techniques. A human thorax phantom was developed with insertable modules representing lung, liver, ribs and additional tracking spheres. The quality of human tissue mimicking characteristics was evaluated for (1)H and (23)Na MR as well as CT imaging. The position of landmarks in the lung lobes was tracked during CT image acquisition at several positions during breathing cycles. (1)H MR measurements of the liver were repeated after seven months to determine long term stability. The modules possess HU, T1 and T2 values comparable to human tissues (lung module: -756±148HU, artificial ribs: 218±56HU (low CaCO3 concentration) and 339±121 (high CaCO3 concentration), liver module: T1=790±28ms, T2=65±1ms). Motion analysis showed that the landmarks in the lung lobes follow a 3D trajectory similar to human breathing motion. The tracking spheres are well detectable in both CT and MRI. The parameters of the tracking spheres can be adjusted in the following ranges to result in a distinct signal: HU values from 150 to 900HU, T1 relaxation time from 550ms to 2000ms, T2 relaxation time from 40ms to 200ms. The presented anthropomorphic multimodal thorax phantom fulfills the demands of a simple, inexpensive system with interchangeable components. In future, the modular design allows for complementing the present set up with additional modules focusing on specific research targets such as perfusion studies, (23)Na MR quantification experiments and an increasing level of complexity for motion studies. Copyright © 2016. Published by Elsevier GmbH.

  2. Irreversible change in the T1 temperature dependence with thermal dose using the proton resonance frequency-T1 technique.

    PubMed

    Diakite, Mahamadou; Payne, Allison; Todd, Nick; Parker, Dennis L

    2013-04-01

    Denaturation of macromolecules within the tissues is believed to be the major factor contributing to the damage of tissues upon hyperthermia. As a result, the value of the spin-lattice relaxation time T1 of the tissue water, which is related to the translational and rotational rates of water, represents an intrinsic probe for investigating structural changes in tissues at high temperature. Therefore, the goal of this work is to investigate whether the simultaneous measurement of temperature and T1 using a hybrid proton resonance frequency (PRF)-T1 measurement technique can be used to detect irreversible changes in T1 that might be indicative of tissue damage. A new hybrid PRF-T1 sequence was implemented based on the variable flip angle driven-equilibrium single-pulse observation (DESPOT)1 method from a standard three dimensional segmented echo-planar imaging sequence by alternating two flip angles from measurement to measurement. The structural changes of the heated tissue volumes were analyzed based on the derived T1 values and the corresponding PRF temperatures. Using the hybrid PRF-T1 technique, we demonstrate that the change of spin lattice relaxation time T1 is reversible with temperature for low thermal dose (thermal dose ≤ 240 cumulative equivalent minutes [CEM] 43°C) and irreversible with temperature after significant accumulation of thermal dose in ex vivo chicken breast tissue. These results suggest that the hybrid PRF-T1 method may be a potentially powerful tool to investigate the extent and mechanism of heat damage of biological tissues.

  3. T1 mapping for diagnosis of mild chronic pancreatitis.

    PubMed

    Tirkes, Temel; Lin, Chen; Fogel, Evan L; Sherman, Stuart S; Wang, Qiushi; Sandrasegaran, Kumaresan

    2017-04-01

    To determine if the T1 relaxation time of the pancreas can detect parenchymal changes in mild chronic pancreatitis (CP). This Institutional Review Board (IRB)-approved, Health Insurance Portability and Accountability Act (HIPAA)-compliant retrospective study analyzed 98 patients with suspected mild CP. Patients were grouped as normal (n = 53) or mild CP (n = 45) based on history, presenting symptomatology, and concordant findings on both the secretin-enhanced magnetic resonance cholangiopancreatography (S-MRCP) and endoscopic retrograde cholangiopancreatography (ERCP). T1 maps were obtained in all patients using the same 3D gradient echo technique on the same 3T scanner. T1 relaxation times, fat signal fraction (FSF), and anterior-posterior (AP) diameter were correlated with the clinical diagnosis of CP. There was a significant difference (P < 0.0001) in the T1 relaxation times between the control (mean = 797 msec, 95% confidence interval [CI]: 730, 865) and mild CP group (mean = 1099 msec, 95% CI: 1032, 1166). A T1 relaxation time threshold value of 900 msec was 80% sensitive (95% CI: 65, 90) and 69% specific (95% CI: 56, 82) for the diagnosis of mild CP (area under the curve [AUC]: 0.81). Multiple regression analysis showed that T1 relaxation time was the only statistically significant variable correlating with the diagnosis of CP (P < 0.0001). T1 relaxation times showed a weak positive correlation with the pancreatic FSF (ρ = 0.33, P = 0.01) in the control group, but not in the mild CP group. The T1 relaxation time of the pancreatic parenchyma was significantly increased in patients with mild CP. Therefore, T1 mapping might be used as a practical quantitative imaging technique for the evaluation of suspected mild CP. 3 J. Magn. Reson. Imaging 2017;45:1171-1176. © 2016 International Society for Magnetic Resonance in Medicine.

  4. Formation of a dinuclear copper(II) complex through the cleavage of Cvalue='Single-Bond'/>N bond of 1-benzoyl-3-(pyridin-2-yl)-1H-pyrazole

    SciTech Connect

    Shardin, Rosidah; Pui, Law Kung; Yamin, Bohari M.; Kassim, Mohammad B.

    2014-09-03

    A simple mononuclear octahedral copper(II) complex was attempted from the reaction of three moles of 1-benzoyl-3-(pyridin-2-yl)-1H-pyrazole and one mole of copper(II) perchlorate hexahydrate in methanol. However, the product of the reaction was confirmed to be a dinuclear copper(II) complex with μ-(3-(pyridin-2-yl)-pyrazolato) and 3-(pyridin-2-yl)-1H-pyrazole ligands attached to each of the Cu(II) centre atom. The copper(II) ion assisted the cleavage of the C{sub benzoyl}value='Single-Bond'/>N bond afforded a 3-(pyridin-2-yl)-1H-pyrazole molecule. Deprotonation of the 3-(pyridin-2-yl)-1H-pyrazole gave a 3-(pyridin-2-yl)-pyrazolato, which subsequently reacted with the Cu(II) ion to give the (3-(pyridin-2-yl)-pyrazolato)(3-(pyridin-2-yl)-1H-pyrazole)Cu(II) product moiety. The structure of the dinuclear complex was confirmed by x-ray crystallography. The complex crystallized in a monoclinic crystal system with P2(1)/n space group and cell dimensions of a = 12.2029(8) Å, b = 11.4010(7) Å, c = 14.4052(9) Å and β = 102.414(2)°. The compound was further characterized by mass spectrometry, CHN elemental analysis, infrared and UV-visible spectroscopy and the results concurred with the x-ray structure. The presence of d-d transition at 671 nm (ε = 116 dm{sup 3} mol{sup −1} cm{sup −1}) supports the presence of Cu(II) centres.

  5. Formation of a dinuclear copper(II) complex through the cleavage of Cvalue='Single_Bond'/>N bond of 1-benzoyl-3-(pyridin-2-yl)-1H-pyrazole

    NASA Astrophysics Data System (ADS)

    Shardin, Rosidah; Pui, Law Kung; Yamin, Bohari M.; Kassim, Mohammad B.

    2014-09-01

    A simple mononuclear octahedral copper(II) complex was attempted from the reaction of three moles of 1-benzoyl-3-(pyridin-2-yl)-1H-pyrazole and one mole of copper(II) perchlorate hexahydrate in methanol. However, the product of the reaction was confirmed to be a dinuclear copper(II) complex with μ-{3-(pyridin-2-yl)-pyrazolato} and 3-(pyridin-2-yl)-1H-pyrazole ligands attached to each of the Cu(II) centre atom. The copper(II) ion assisted the cleavage of the Cbenzoylvalue='Single_Bond'/>N bond afforded a 3-(pyridin-2-yl)-1H-pyrazole molecule. Deprotonation of the 3-(pyridin-2-yl)-1H-pyrazole gave a 3-(pyridin-2-yl)-pyrazolato, which subsequently reacted with the Cu(II) ion to give the {3-(pyridin-2-yl)-pyrazolato}{3-(pyridin-2-yl)-1H-pyrazole}Cu(II) product moiety. The structure of the dinuclear complex was confirmed by x-ray crystallography. The complex crystallized in a monoclinic crystal system with P2(1)/n space group and cell dimensions of a = 12.2029(8) Å, b = 11.4010(7) Å, c = 14.4052(9) Å and β = 102.414(2)°. The compound was further characterized by mass spectrometry, CHN elemental analysis, infrared and UV-visible spectroscopy and the results concurred with the x-ray structure. The presence of d-d transition at 671 nm (ɛ = 116 dm3 mol-1 cm-1) supports the presence of Cu(II) centres.

  6. Native T1 Mapping Demonstrating Apical Thrombi in Eosinophilic Myocarditis Associated with Churg-Strauss Syndrome

    PubMed Central

    Beck, Kyongmin Sarah; Jeong, Soh Yong; Lee, Kyo Young; Chang, Kiyuk

    2016-01-01

    Eosinophilic myocarditis is a disease characterized by eosinophilic infiltration of the myocardium, consisting of acute necrotic stage, thrombotic stage, and fibrotic stage. Although T1 mapping has been increasingly used in various cardiac pathologies, there has been no report of T1 mapping in eosinophilic myocarditis. We report a case of 75-year-old female with eosinophilic myocarditis, whose cardiac magnetic resonance imaging included native T1 mapping, in which apical thrombi were distinctly seen as areas with decreased T1 values, next to areas of inflammation seen as increased T1 value in subendocardium. PMID:27826352

  7. The Effect of Three Times a Week Glatiramer Acetate on Cerebral T1 Hypointense Lesions in Relapsing-Remitting Multiple Sclerosis.

    PubMed

    Zivadinov, Robert; Dwyer, Michael G; Ramasamy, Deepa P; Davis, Mat D; Steinerman, Joshua R; Khan, Omar

    2015-01-01

    Two definitions of T1 hypointense (T1H) lesions can be derived from pre-contrast images: those that may or may not have a corresponding gadolinium-enhancing correlate on post-contrast images (T1H total), and those that are simultaneously non-gadolinium-enhancing on post-contrast scans (T1H non-enhancing). To determine the differences in lesion evolution between these two T1H definitions, we examined the effect of glatiramer acetate 40 mg/mL three times weekly subcutaneous injection (GA40) on the number of new or enlarging T1H total and T1H non-enhancing lesions in patients with relapsing-remitting multiple sclerosis (RRMS). The Phase III GALA study randomized 1404 RRMS subjects 2:1 to receive GA40 or placebo for 12 months. MRI scans were obtained at baseline and at months 6 and 12. Cumulative numbers of T1H total and of T1H non-enhancing lesions were analyzed using an adjusted negative binomial regression model. A total of 1,357 patients had MRI data collected at either the month 6 or month 12 visit. Among the 1,357 patients with MRI scans performed at either the month 6 or month 12 visit, 883 treated with GA40 developed an adjusted cumulative mean of 1.72 T1H total lesions versus 2.62 in 440 placebo controls (risk ratio, .66; 95% CI, .54-.80; P < .0001). On T1H non-enhanced scans, GA40-treated patients developed an adjusted cumulative mean of 1.35 T1H non-enhancing lesions versus 1.91 in placebo controls (risk ratio, .71; CI, .58-.87; P = .0009). GA40 significantly reduced the number of new or enlarging T1H total lesions and T1H non-enhancing lesions compared with placebo. Although the treatment effect magnitude was comparable with both definitions, the use of T1H non-enhancing lesions may be more relevant for more uniform standardization in future clinical trials. © 2015 The Authors. Journal of Neuroimaging published by Wiley Periodicals, Inc. on behalf of American Society of Neuroimaging.

  8. The Effect of Three Times a Week Glatiramer Acetate on Cerebral T1 Hypointense Lesions in Relapsing‐Remitting Multiple Sclerosis

    PubMed Central

    Dwyer, Michael G.; Ramasamy, Deepa P.; Davis, Mat D.; Steinerman, Joshua R.; Khan, Omar

    2015-01-01

    ABSTRACT BACKGROUND AND PURPOSE Two definitions of T1 hypointense (T1H) lesions can be derived from pre‐contrast images: those that may or may not have a corresponding gadolinium‐enhancing correlate on post‐contrast images (T1H total), and those that are simultaneously non‐gadolinium‐enhancing on post‐contrast scans (T1H non‐enhancing). To determine the differences in lesion evolution between these two T1H definitions, we examined the effect of glatiramer acetate 40 mg/mL three times weekly subcutaneous injection (GA40) on the number of new or enlarging T1H total and T1H non‐enhancing lesions in patients with relapsing‐remitting multiple sclerosis (RRMS). METHODS The Phase III GALA study randomized 1404 RRMS subjects 2:1 to receive GA40 or placebo for 12 months. MRI scans were obtained at baseline and at months 6 and 12. Cumulative numbers of T1H total and of T1H non‐enhancing lesions were analyzed using an adjusted negative binomial regression model. A total of 1,357 patients had MRI data collected at either the month 6 or month 12 visit. RESULTS Among the 1,357 patients with MRI scans performed at either the month 6 or month 12 visit, 883 treated with GA40 developed an adjusted cumulative mean of 1.72 T1H total lesions versus 2.62 in 440 placebo controls (risk ratio, .66; 95% CI, .54‐.80; P < .0001). On T1H non‐enhanced scans, GA40‐treated patients developed an adjusted cumulative mean of 1.35 T1H non‐enhancing lesions versus 1.91 in placebo controls (risk ratio, .71; CI, .58‐.87; P = .0009). CONCLUSIONS GA40 significantly reduced the number of new or enlarging T1H total lesions and T1H non‐enhancing lesions compared with placebo. Although the treatment effect magnitude was comparable with both definitions, the use of T1H non‐enhancing lesions may be more relevant for more uniform standardization in future clinical trials. PMID:26394270

  9. Multiacquisition T1-mapping MRI during tidal respiration for quantification of myocardial T1 in swine with heart failure.

    PubMed

    Hood, Maureen N; Song, Ting; Bedocs, Peter; Capacchione, John F; Kasper, Christine E; Haigney, Mark C; Ho, Vincent B

    2013-10-01

    The purpose of this article is to evaluate a free-breathing pulse sequence to quantify myocardial T1 changes in a swine model of tachycardia-induced heart failure. Yorkshire swine were implanted with pacemakers and were ventricularly paced at 200 beats/min to induce heart failure. Animals were scanned twice with a 1.5-T MRI scanner, once at baseline and once at heart failure. A T1-mapping sequence was performed during tidal respiration before and 5 minutes after the administration of a gadolinium-chelate contrast agent. T1-mapping values were compared between the baseline and heart failure scans. The percentage of fibrosis of heart failure myocardial tissue was compared with similar left ventricular tissue from control animals using trichrome blue histologic analysis. In the study cohort, differences were found between the baseline and heart failure T1-mapping values before the administration of contrast agent (960 ± 96 and 726 ± 94 ms, respectively; p = 0.02) and after contrast agent administration (546 ± 180 and 300 ± 171 ms, respectively; p = 0.005). The animals with heart failure also had a difference histologically in the percentage of myocardial collagen compared with tissue from healthy control animals (control, 5.4% ± 1.0%; heart failure, 9.4% ± 1.6%; p < 0.001). The proposed T1-mapping technique can quantify diffuse myocardial changes associated with heart failure without the use of a contrast agent and without breath-holding. These T1 changes appear to be associated with increases in the percentage of myocardial collagen that in this study were not detected by traditional myocardial delayed enhancement imaging. T1 mapping may be a useful technique for detecting early but clinically significant myocardial fibrosis.

  10. Metabolic atrophy and 3-T 1H-magnetic resonance spectroscopy correlation after radiation therapy for prostate cancer.

    PubMed

    Panebianco, Valeria; Barchetti, Flavio; Musio, Daniela; Forte, Valerio; Pace, Alberto; De Felice, Francesca; Barchetti, Giovanni; Tombolini, Vincenzo; Catalano, Carlo

    2014-12-01

    To correlate 3-T magnetic resonance spectroscopic imaging (MRSI) with prostate-specific antigen (PSA) levels in patients with prostate cancer treated with external beam radiation therapy to assess the potential advantages of MRSI. A total of 50 patients (age range 65-83 years) underwent PSA and MRSI surveillance before and at 3, 6, 12, 18 and 24 months after radiotherapy. Of the 50 patients examined, 13 patients completely responded to therapy showing metabolic atrophy (MA), defined as a choline-plus-creatine/citrate (CC/C) ratio <0.2, at 3 months; in this group none had biochemical relapse (PSA nadir + 2 ng/mL) by the end of the follow-up. Of the 50 patients, 35 showed a partial response to therapy (CC/C ratio between 0.2 and 0.8) at 3 and 6 months and, of these 35 patients, 30 reached MA at 12 months, while five developed a recurrence (CC/C ratio >0.8). Three of those patients with recurrence had a biochemical relapse at 18 months and the other two at 24 months. Two of the 50 patients did not respond to the treatment, showing persistent disease from the 3rd month (CC/C ratio >0.8); one patient had biochemical relapse at 6 and the other at 12 months. MRSI was shown to have a greater potential than PSA level in monitoring patients after radiotherapy, because it anticipates PSA nadir, and biochemical relapse in particular. © 2013 The Authors. BJU International © 2013 BJU International.

  11. The T1D Exchange clinic registry.

    PubMed

    Beck, Roy W; Tamborlane, William V; Bergenstal, Richard M; Miller, Kellee M; DuBose, Stephanie N; Hall, Callyn A

    2012-12-01

    The T1D Exchange includes a clinic-based registry, a patient-centric web site called Glu, and a biobank. The aim of the study was to describe the T1D Exchange clinic registry and provide an overview of participant characteristics. Data obtained through participant completion of a questionnaire and chart extraction include diabetes history, management, and monitoring; general health; lifestyle; family history; socioeconomic factors; medications; acute and chronic diabetic complications; other medical conditions; and laboratory results. Data were collected from 67 endocrinology centers throughout the United States. We studied 25,833 adults and children with presumed autoimmune type 1 diabetes (T1D). Participants ranged in age from less than 1 to 93 yr, 50% were female, 82% were Caucasian, 50% used an insulin pump, 6% used continuous glucose monitoring, and 16% had a first-degree family member with T1D. Glycosylated hemoglobin at enrollment averaged 8.3% and was highest in 13 to 25 yr olds. The prevalence of renal disease was ≤4% until T1D was present for at least 10 yr, and retinopathy treatment was ≤2% until T1D was present for at least 20 yr. A severe hypoglycemic event (seizure or coma) in the prior 12 months was reported by 7% of participants and diabetic ketoacidosis in the prior 12 months by 8%. The T1D Exchange clinic registry provides a database of important information on individuals with T1D in the United States. The rich dataset of the registry provides an opportunity to address numerous issues of relevance to clinicians and patients, including assessments of associations between patient characteristics and diabetes management factors with outcomes.

  12. Hyperpolarized (129)Xe T (1) in oxygenated and deoxygenated blood

    NASA Technical Reports Server (NTRS)

    Albert, M. S.; Balamore, D.; Kacher, D. F.; Venkatesh, A. K.; Jolesz, F. A.

    2000-01-01

    The viability of the new technique of hyperpolarized (129)Xe MRI (HypX-MRI) for imaging organs other than the lungs depends on whether the spin-lattice relaxation time, T(1), of (129)Xe is sufficiently long in the blood. In previous experiments by the authors, the T(1) was found to be strongly dependent upon the oxygenation of the blood, with T(1) increasing from about 3 s in deoxygenated samples to about 10 s in oxygenated samples. Contrarily, Tseng et al. (J. Magn. Reson. 1997; 126: 79-86) reported extremely long T(1) values deduced from an indirect experiment in which hyperpolarized (129)Xe was used to create a 'blood-foam'. They found that oxygenation decreased T(1). Pivotal to their experiment is the continual and rapid exchange of hyperpolarized (129)Xe between the gas phase (within blood-foam bubbles) and the dissolved phase (in the skin of the bubbles); this necessitated a complicated analysis to extract the T(1) of (129)Xe in blood. In the present study, the experimental design minimizes gas exchange after the initial bolus of hyperpolarized (129)Xe has been bubbled through the sample. This study confirms that oxygenation increases the T(1) of (129)Xe in blood, from about 4 s in freshly drawn venous blood, to about 13 s in blood oxygenated to arterial levels, and also shifts the red blood cell resonance to higher frequency. Copyright 2000 John Wiley & Sons, Ltd. Abbreviations used BOLD blood oxygen level dependent NOE nuclear overhouses effect PO(2) oxygen partial pressure RBC red blood cells RF radio frequency SNR signal-to-noise ratio.

  13. Hyperpolarized (129)Xe T (1) in oxygenated and deoxygenated blood

    NASA Technical Reports Server (NTRS)

    Albert, M. S.; Balamore, D.; Kacher, D. F.; Venkatesh, A. K.; Jolesz, F. A.

    2000-01-01

    The viability of the new technique of hyperpolarized (129)Xe MRI (HypX-MRI) for imaging organs other than the lungs depends on whether the spin-lattice relaxation time, T(1), of (129)Xe is sufficiently long in the blood. In previous experiments by the authors, the T(1) was found to be strongly dependent upon the oxygenation of the blood, with T(1) increasing from about 3 s in deoxygenated samples to about 10 s in oxygenated samples. Contrarily, Tseng et al. (J. Magn. Reson. 1997; 126: 79-86) reported extremely long T(1) values deduced from an indirect experiment in which hyperpolarized (129)Xe was used to create a 'blood-foam'. They found that oxygenation decreased T(1). Pivotal to their experiment is the continual and rapid exchange of hyperpolarized (129)Xe between the gas phase (within blood-foam bubbles) and the dissolved phase (in the skin of the bubbles); this necessitated a complicated analysis to extract the T(1) of (129)Xe in blood. In the present study, the experimental design minimizes gas exchange after the initial bolus of hyperpolarized (129)Xe has been bubbled through the sample. This study confirms that oxygenation increases the T(1) of (129)Xe in blood, from about 4 s in freshly drawn venous blood, to about 13 s in blood oxygenated to arterial levels, and also shifts the red blood cell resonance to higher frequency. Copyright 2000 John Wiley & Sons, Ltd. Abbreviations used BOLD blood oxygen level dependent NOE nuclear overhouses effect PO(2) oxygen partial pressure RBC red blood cells RF radio frequency SNR signal-to-noise ratio.

  14. Reproducibility and comparison of oxygen-enhanced T1 quantification in COPD and asthma patients

    PubMed Central

    Jobst, Bertram J.; Anjorin, Angela; Sedlaczek, Oliver; Wolf, Ursula; Terekhov, Maxim; Hoffmann, Christian; Ley, Sebastian; Düber, Christoph; Biederer, Jürgen; Kauczor, Hans-Ulrich; Jakob, Peter M.; Wielpütz, Mark O.

    2017-01-01

    T1 maps have been shown to yield useful diagnostic information on lung function in patients with chronic obstructive pulmonary disease (COPD) and asthma, both for native T1 and ΔT1, the relative reduction while breathing pure oxygen. As parameter quantification is particularly interesting for longitudinal studies, the purpose of this work was both to examine the reproducibility of lung T1 mapping and to compare T1 found in COPD and asthma patients using IRSnapShotFLASH embedded in a full MRI protocol. 12 asthma and 12 COPD patients (site 1) and further 15 COPD patients (site 2) were examined on two consecutive days. In each patient, T1 maps were acquired in 8 single breath-hold slices, breathing first room air, then pure oxygen. Maps were partitioned into 12 regions each to calculate average values. In asthma patients, the average T1,RA = 1206ms (room air) was reduced to T1,O2 = 1141ms under oxygen conditions (ΔT1 = 5.3%, p < 5⋅10−4), while in COPD patients both native T1,RA = 1125ms was significantly shorter (p < 10−3) and the relative reduction to T1,O2 = 1081ms on average ΔT1 = 4.2%(p < 10−5). On the second day, with T1,RA = 1186ms in asthma and T1,RA = 1097ms in COPD, observed values were slightly shorter on average in all patient groups. ΔT1 reduction was the least repeatable parameter and varied from day to day by up to 23% in individual asthma and 30% in COPD patients. While for both patient groups T1 was below the values reported for healthy subjects, the T1 and ΔT1 found in asthmatics lies between that of the COPD group and reported values for healthy subjects, suggesting a higher blood volume fraction and better ventilation. However, it could be demonstrated that lung T1 quantification is subject to notable inter-examination variability, which here can be attributed both to remaining contrast agent from the previous day and the increased dependency of lung T1 on perfusion and thus current lung state. PMID:28207845

  15. Magnetic Resonance Water Proton Relaxation in Protein Solutions and Tissue: T1ρ Dispersion Characterization

    PubMed Central

    Chen, Enn-Ling; Kim, Raymond J.

    2010-01-01

    Background Image contrast in clinical MRI is often determined by differences in tissue water proton relaxation behavior. However, many aspects of water proton relaxation in complex biological media, such as protein solutions and tissue are not well understood, perhaps due to the limited empirical data. Principal Findings Water proton T1, T2, and T1ρ of protein solutions and tissue were measured systematically under multiple conditions. Crosslinking or aggregation of protein decreased T2 and T1ρ, but did not change high-field T1. T1ρ dispersion profiles were similar for crosslinked protein solutions, myocardial tissue, and cartilage, and exhibited power law behavior with T1ρ(0) values that closely approximated T2. The T1ρ dispersion of mobile protein solutions was flat above 5 kHz, but showed a steep curve below 5 kHz that was sensitive to changes in pH. The T1ρ dispersion of crosslinked BSA and cartilage in DMSO solvent closely resembled that of water solvent above 5 kHz but showed decreased dispersion below 5 kHz. Conclusions Proton exchange is a minor pathway for tissue T1 and T1ρ relaxation above 5 kHz. Potential models for relaxation are discussed, however the same molecular mechanism appears to be responsible across 5 decades of frequencies from T1ρ to T1. PMID:20052404

  16. Advanced Colloids Experiment (ACE-T1)

    NASA Technical Reports Server (NTRS)

    Meyer, William V.; Sicker, Ron; Brown, Dan; Eustace, John

    2015-01-01

    Increment 45 - 46 Science Symposium presentation of Advanced Colloids Experiment (ACE-T1) to RPO. The purpose of this event is for Principal Investigators to present their science objectives, testing approach, and measurement methods to agency scientists, managers, and other investigators.

  17. Phosphorus Taste Involves T1R2 and T1R3.

    PubMed

    Tordoff, Michael G

    2017-06-01

    Rodents consume solutions of phosphates and pyrophosphates in preference to water. Recently, we found that the preference for trisodium pyrophosphate (Na3HP2O7) was greater in T1R3 knockout (KO) mice than wild-type (WT) controls, suggesting that T1R3 is a pyrophosphate detector. We now show that this heightened Na3HP2O7 preference of T1R3 KO mice extends to disodium phosphate (Na2HPO4), disodium and tetrasodium pyrophosphate (Na2H2PO4 and Na4H2PO4), a tripolyphosphate (Na5P3O10), a non-sodium phosphate [(NH4)2HPO4], and a non-sodium pyrophosphate (K4P2O7) but not to non-P salts with large anions (sodium gluconate, acetate, or propionate). Licking rates for Na3HP2O7 are higher in T1R2 KO mice than WT controls; Na3HP2O7 preference scores are increased even more in T1R2 KO mice and T1R2+T1R3 double KO mice than in T1R3 KO mice; preference scores for Na3HP2O7 are normal in T1R1 KO mice. These results implicate each subunit of the T1R2+T1R3 dimer in the behavioral response to P-containing taste compounds. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Adiabatic inversion pulses for myocardial T1-mapping

    PubMed Central

    Kellman, Peter; Herzka, Daniel A.; Hansen, Michael Schacht

    2013-01-01

    Purpose To evaluate the error in T1-estimates using inversion recovery based T1-mapping due to imperfect inversion, and perform a systematic study of adiabatic inversion pulse designs in order to maximize inversion efficiency for values of transverse relaxation (T2) in the myocardium subject to a peak power constraint. Methods The inversion factor for hyperbolic secant (HS) and tangent/hyperbolic tangent (tan/tanh) adiabatic full passage waveforms was calculated using Bloch equations. A brute force search was conducted of design parameters: pulse duration, frequency range, shape parameters, and peak amplitude. A design was selected that maximized the inversion factor over a specified range of amplitude and off-resonance and validated using phantom measurements. Empirical correction for imperfect inversion was performed. Results The tan/tanh adiabatic pulse was found to outperform HS designs, and achieve an inversion factor of 0.96 within ±150 Hz over 25% amplitude range with 14.7 μTesla peak amplitude. T1-mapping errors of the selected design due to imperfect inversion was approx. 4% and could be corrected to <1%. Conclusion Non-ideal inversion leads to significant errors in inversion recovery based T1-mapping. The inversion efficiency of adiabatic pulses is sensitive to transverse relaxation. The tan/tanh design achieved the best performance subject to the peak amplitude constraint. PMID:23722695

  19. Are turns required for the folding of ribonuclease T1?

    PubMed Central

    Garrett, J. B.; Mullins, L. S.; Raushel, F. M.

    1996-01-01

    Ribonuclease T1 (RNase T1) is a small, globular protein of 104 amino acids for which extensive thermodynamic and structural information is known. To assess the specific influence of variations in amino acid sequence on the mechanism for protein folding, circularly permuted variants of RNase T1 were constructed and characterized in terms of catalytic activity and thermodynamic stability. The disulfide bond connecting Cys-2 and Cys-10 was removed by mutation of these residues to alanine (C2, 10A) to avoid potential steric problems imposed by the circular permutations. The original amino-terminus and carboxyl-terminus of the mutant (C2, 10A) were subsequently joined with a tripeptide linker to accommodate a reverse turn and new termini were introduced throughout the primary sequence in regions of solvent-exposed loops at Ser-35 (cp35S1), Asp-49 (cp49D1), Gly-70 (cp70G1), and Ser-96 (cp96S1). These circularly permuted RNase T1 mutants retained 35-100% of the original catalytic activity for the hydrolysis of guanylyl(3'-->5')cytidine, suggesting that the overall tertiary fold of these mutants is very similar to that of wild-type protein. Chemical denaturation curves indicated thermodynamic stabilities at pH 5.0 of 5.7, 2.9, 2.6, and 4.6 kcal/mol for cp35S1, cp49D1, cp70G1, and cp96S1, respectively, compared to a value of 10.1 kcal/mol for wild-type RNase T1 and 6.4 kcal/mol for (C2, 10A) T1. A fifth set of circularly permuted variants was attempted with new termini positioned in a tight beta-turn between Glu-82 and Gln-85. New termini were inserted at Asn-83 (cp83N1), Asn-84 (cp84N1), and Gln-85 (cp85Q1). No detectable amount of protein was ever produced for any of the mutations in this region, suggesting that this turn may be critical for the proper folding and/or thermodynamic stability of RNase T1. PMID:8745397

  20. The cysteine-rich domain of human T1R3 is necessary for the interaction between human T1R2-T1R3 sweet receptors and a sweet-tasting protein, thaumatin.

    PubMed

    Ohta, Keisuke; Masuda, Tetsuya; Tani, Fumito; Kitabatake, Naofumi

    2011-03-18

    Thaumatin is an intensely sweet-tasting protein perceived by humans but not rodents. Its threshold value of sweetness in humans is 50nM, the lowest of any sweet-tasting protein. In the present study, the sites where sweet receptors interact with thaumatin were investigated using human embryonic kidney 293 (HEK293) cells expressing the sweet receptors T1R2-T1R3. Chimeric human- mouse sweet receptors were constructed and their responses to sweeteners were investigated. The human (h) T1R2- mouse (m) T1R3 combination responded to sucralose but not to thaumatin, clearly indicating that a T1R3 subunit from humans is necessary for the interaction with thaumatin. Furthermore, results obtained from using chimeric T1R3s showed that the cysteine-rich domain (CRD) of human T1R3 is important for the interaction with thaumatin. The CRD of T1R3 would be a prominent target for designing new sweeteners. Copyright © 2011 Elsevier Inc. All rights reserved.

  1. T1 bright appendix sign to exclude acute appendicitis in pregnant women.

    PubMed

    Shin, Ilah; An, Chansik; Lim, Joon Seok; Kim, Myeong-Jin; Chung, Yong Eun

    2017-08-01

    To evaluate the diagnostic value of the T1 bright appendix sign for the diagnosis of acute appendicitis in pregnant women. This retrospective study included 125 pregnant women with suspected appendicitis who underwent magnetic resonance (MR) imaging. The T1 bright appendix sign was defined as a high intensity signal filling more than half length of the appendix on T1-weighted imaging. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the T1 bright appendix sign for normal appendix identification were calculated in all patients and in those with borderline-sized appendices (6-7 mm). The T1 bright appendix sign was seen in 51% of patients with normal appendices, but only in 4.5% of patients with acute appendicitis. The overall sensitivity, specificity, PPV, and NPV of the T1 bright appendix sign for normal appendix diagnosis were 44.9%, 95.5%, 97.6%, and 30.0%, respectively. All four patients with borderline sized appendix with appendicitis showed negative T1 bright appendix sign. The T1 bright appendix sign is a specific finding for the diagnosis of a normal appendix in pregnant women with suspected acute appendicitis. • Magnetic resonance imaging is increasingly used in emergency settings. • Acute appendicitis is the most common cause of acute abdomen. • Magnetic resonance imaging is widely used in pregnant population. • T1 bright appendix sign can be a specific sign representing normal appendix.

  2. Distinct Human and Mouse Membrane Trafficking Systems for Sweet Taste Receptors T1r2 and T1r3

    PubMed Central

    Shimizu, Madoka; Goto, Masao; Kawai, Takayuki; Yamashita, Atsuko; Kusakabe, Yuko

    2014-01-01

    The sweet taste receptors T1r2 and T1r3 are included in the T1r taste receptor family that belongs to class C of the G protein-coupled receptors. Heterodimerization of T1r2 and T1r3 is required for the perception of sweet substances, but little is known about the mechanisms underlying this heterodimerization, including membrane trafficking. We developed tagged mouse T1r2 and T1r3, and human T1R2 and T1R3 and evaluated membrane trafficking in human embryonic kidney 293 (HEK293) cells. We found that human T1R3 surface expression was only observed when human T1R3 was coexpressed with human T1R2, whereas mouse T1r3 was expressed without mouse T1r2 expression. A domain-swapped chimera and truncated human T1R3 mutant showed that the Venus flytrap module and cysteine-rich domain (CRD) of human T1R3 contain a region related to the inhibition of human T1R3 membrane trafficking and coordinated regulation of human T1R3 membrane trafficking. We also found that the Venus flytrap module of both human T1R2 and T1R3 are needed for membrane trafficking, suggesting that the coexpression of human T1R2 and T1R3 is required for this event. These results suggest that the Venus flytrap module and CRD receive taste substances and play roles in membrane trafficking of human T1R2 and T1R3. These features are different from those of mouse receptors, indicating that human T1R2 and T1R3 are likely to have a novel membrane trafficking system. PMID:25029362

  3. Distinct human and mouse membrane trafficking systems for sweet taste receptors T1r2 and T1r3.

    PubMed

    Shimizu, Madoka; Goto, Masao; Kawai, Takayuki; Yamashita, Atsuko; Kusakabe, Yuko

    2014-01-01

    The sweet taste receptors T1r2 and T1r3 are included in the T1r taste receptor family that belongs to class C of the G protein-coupled receptors. Heterodimerization of T1r2 and T1r3 is required for the perception of sweet substances, but little is known about the mechanisms underlying this heterodimerization, including membrane trafficking. We developed tagged mouse T1r2 and T1r3, and human T1R2 and T1R3 and evaluated membrane trafficking in human embryonic kidney 293 (HEK293) cells. We found that human T1R3 surface expression was only observed when human T1R3 was coexpressed with human T1R2, whereas mouse T1r3 was expressed without mouse T1r2 expression. A domain-swapped chimera and truncated human T1R3 mutant showed that the Venus flytrap module and cysteine-rich domain (CRD) of human T1R3 contain a region related to the inhibition of human T1R3 membrane trafficking and coordinated regulation of human T1R3 membrane trafficking. We also found that the Venus flytrap module of both human T1R2 and T1R3 are needed for membrane trafficking, suggesting that the coexpression of human T1R2 and T1R3 is required for this event. These results suggest that the Venus flytrap module and CRD receive taste substances and play roles in membrane trafficking of human T1R2 and T1R3. These features are different from those of mouse receptors, indicating that human T1R2 and T1R3 are likely to have a novel membrane trafficking system.

  4. 1H-detected 1H- 1H correlation spectroscopy of a stereo-array isotope labeled amino acid under fast magic-angle spinning

    NASA Astrophysics Data System (ADS)

    Takahashi, Hiroki; Kainosho, Masatsune; Akutsu, Hideo; Fujiwara, Toshimichi

    2010-04-01

    The combined use of selective deuteration, stereo-array isotope labeling (SAIL), and fast magic-angle spinning effectively suppresses the 1H-1H dipolar couplings in organic solids. This method provided the high-field 1H NMR linewidths comparable to those achieved by combined rotation and multiple-pulse spectroscopy. This technique was applied to two-dimensional 1H-detected 1H-1H polarization transfer CHH experiments of valine. The signal sensitivity for the 1H-detected CHH experiments was greater than that for the 13C-detected 1H-1H polarization transfer experiments by a factor of 2-4. We obtained the 1H-1H distances in SAIL valine by CHH experiments with an accuracy of about 0.2 Å by using a theory developed for 1H-1H polarization transfer in 13C-labeled organic compounds.

  5. 23Na and (1)H NMR microimaging of intact plants.

    PubMed

    Olt, S; Krötz, E; Komor, E; Rokitta, M; Haase, A

    2000-06-01

    (23)Na NMR microimaging is described to map, for the first time, the sodium distribution in living plants. As an example, the response of 6-day-old seedlings of Ricinus communis to exposure to sodium chloride concentrations from 5 to 300 mM was observed in vivo using (23)Na as well as (1)H NMR microimaging. Experiments were performed at 11.75 T with a double resonant (23)Na-(1)H probehead. The probehead was homebuilt and equipped with a climate chamber. T(1) and T(2) of (23)Na were measured in the cross section of the hypocotyl. Within 85 min (23)Na images with an in-plane resolution of 156 x 156 micrometer were acquired. With this spatial information, the different types of tissue in the hypocotyl can be discerned. The measurement time appears to be short compared to the time scale of sodium uptake and accumulation in the plant so that the kinetics of salt stress can be followed. In conclusion, (23)Na NMR microimaging promises great potential for physiological studies of the consequences of salt stress on the macroscopic level and thus may become a unique tool for characterizing plants with respect to salt tolerance and salt sensitivity. Copyright 2000 Academic Press.

  6. 23Na and 1H NMR Microimaging of Intact Plants

    NASA Astrophysics Data System (ADS)

    Olt, Silvia; Krötz, Eva; Komor, Ewald; Rokitta, Markus; Haase, Axel

    2000-06-01

    23Na NMR microimaging is described to map, for the first time, the sodium distribution in living plants. As an example, the response of 6-day-old seedlings of Ricinus communis to exposure to sodium chloride concentrations from 5 to 300 mM was observed in vivo using 23Na as well as 1H NMR microimaging. Experiments were performed at 11.75 T with a double resonant 23Na-1H probehead. The probehead was homebuilt and equipped with a climate chamber. T1 and T2 of 23Na were measured in the cross section of the hypocotyl. Within 85 min 23Na images with an in-plane resolution of 156 × 156 μm were acquired. With this spatial information, the different types of tissue in the hypocotyl can be discerned. The measurement time appears to be short compared to the time scale of sodium uptake and accumulation in the plant so that the kinetics of salt stress can be followed. In conclusion, 23Na NMR microimaging promises great potential for physiological studies of the consequences of salt stress on the macroscopic level and thus may become a unique tool for characterizing plants with respect to salt tolerance and salt sensitivity.

  7. Characterization of heroin samples by 1H NMR and 2D DOSY 1H NMR.

    PubMed

    Balayssac, Stéphane; Retailleau, Emmanuel; Bertrand, Geneviève; Escot, Marie-Pierre; Martino, Robert; Malet-Martino, Myriam; Gilard, Véronique

    2014-01-01

    Twenty-four samples of heroin from different illicit drug seizures were analyzed using proton Nuclear Magnetic Resonance ((1)H NMR) and two-dimensional diffusion-ordered spectroscopy (2D DOSY) (1)H NMR. A careful assignment and quantification of (1)H signals enabled a comprehensive characterization of the substances present in the samples investigated: heroin, its main related impurities (6-acetylmorphine, acetylcodeine, morphine, noscapine and papaverine) and cutting agents (caffeine and acetaminophen in nearly all samples as well as lactose, lidocaine, mannitol, piracetam in one sample only), and hence to establish their spectral signatures. The good agreement between the amounts of heroin, noscapine, caffeine and acetaminophen determined by (1)H NMR and gas chromatography, the reference method in forensic laboratories, demonstrates the validity of the (1)H NMR technique. In this paper, 2D DOSY (1)H NMR offers a new approach for a whole characterization of the various components of these complex mixtures.

  8. Values.

    ERIC Educational Resources Information Center

    Chapel Hill City Schools, NC.

    GRADES OR AGES: Grades 1-12. SUBJECT MATTER: Values. ORGANIZATION AND PHYSICAL APPEARANCE: The guide is intended to define the development of the valuing process and contains ideas for classroom teachers. It is not a conventional curriculum guide but is recommended for use with the guide on drug education (SP 007 318). It contains the following…

  9. Enhanced Y1H Assays for Arabidopis

    USDA-ARS?s Scientific Manuscript database

    Transcription regulation plays a key role in development and response to environment. To understand this mechanism, we need to know which transcription factor (TFs) would bind to which promoter, thus regulate their target gene expression. Yeast one-hybrid (Y1H) technique can be used to map this kind...

  10. Reduced Right Ventricular Native Myocardial T1 in Anderson-Fabry Disease: Comparison to Pulmonary Hypertension and Healthy Controls

    PubMed Central

    Pagano, Joseph J.; Chow, Kelvin; Khan, Aneal; Michelakis, Evangelos; Paterson, Ian; Oudit, Gavin Y.; Thompson, Richard B.

    2016-01-01

    Aims Anderson-Fabry disease (AFD) is characterized by progressive multiorgan accumulation of intracellular sphingolipids due to α-galactosidase A enzyme deficiency, resulting in progressive ventricular hypertrophy, heart failure, arrhythmias, and death. Decreased native (non-contrast) left ventricular (LV) T1 (longitudinal relaxation time) with MRI discriminates AFD from healthy controls or other presentations of concentric hypertrophy, but the right ventricle (RV) has not been studied. The aims of the current study were to evaluate native RV T1 values in AFD, with a goal of better understanding the pathophysiology of RV involvement. Methods and Results Native T1 values were measured in the inferior RV wall (RVI), interventricular septum (IVS), and inferior LV (LVI) in patients with AFD, patients with pulmonary hypertension, who provided an alternative RV pathological process for comparison, and healthy controls. A minimum wall thickness of 4 mm was selected to minimize partial volume errors in tissue T1 analysis. T1 analysis was performed in 6 subjects with AFD, 6 subjects with PH, and 21 controls. Native T1 values were shorter (adjusted p<0.05 for all comparisons), independent of location, in subjects with AFD (RVI-T1 = 1096±49 ms, IVS-T1 = 1053±41 ms, LVI-T1 = 1072±44 ms) compared to both PH (RVI-T1 = 1239±41 ms, IVS-T1 = 1280±123 ms, LVI-T1 = 1274±57 ms) and HC (IVS-T1 = 1180±60 ms, LVI-T1 = 1183±45 ms). RVI measurements were not possible in controls due to insufficient wall thickness. Conclusion Native T1 values appear similarly reduced in the left and right ventricles of individuals with AFD and RV wall thickening, suggesting a common pathology. In contrast, individuals with PH and thickened RVs showed increased native T1 values in both ventricles, suggestive of fibrosis. PMID:27305064

  11. Correlation of lactate and pH in human skeletal muscle after exercise by 1H NMR.

    PubMed

    Pan, J W; Hamm, J R; Hetherington, H P; Rothman, D L; Shulman, R G

    1991-07-01

    We have made in vivo 1H NMR measurements of the time course of pH and lactate in human skeletal muscle after exercise. Spectra were obtained in a 4.7-T 30-cm bore Bruker Biospec spectrometer with a 2.5-cm diameter single surface coil. pH was determined from the shift of the endogenous carnosine H-C2 peak while lactate concentrations were determined by comparison with endogenous total creatine, taken to be 28.5 mM/kg wet wt. Fitting the data shows that the exponential decay of lactate (-0.094 +/- 0.014 min-1. t1/2 = 10.6 min) is slower than that of pH (-0.147 +/- 0.015 min-1, t1/2 = 4.7 min), n = 7 with two different volunteers. These values are significantly different with P less than 0.0005. Relaxation times of lactate and creatine were also measured for lactate quantitation; creatine T1, 1.23 +/- 12 s, T2, 136.2 +/- 26.4 ms (both in resting human muscle); lactate T1 (in postmortem rabbit muscle), 1.0 +/- 11 s and T2, 80 ms (in postexercise human muscle). At the end of intense exercise, the lactate level reached was 25.3 +/- 4.0 mM and the average pH drop was 1.0 pH unit. We discuss the implications of these measurements in conjunction with existing data on other sources of H+ flux, phosphocreatine resynthesis, H+ transport, and contribution of inorganic phosphate to buffering.

  12. T1 Mapping in Characterizing Myocardial Disease: A Comprehensive Review.

    PubMed

    Puntmann, Valentina O; Peker, Elif; Chandrashekhar, Y; Nagel, Eike

    2016-07-08

    Cardiovascular magnetic resonance provides insights into myocardial structure and function noninvasively, with high diagnostic accuracy and without ionizing radiation. Myocardial tissue characterization in particular gives cardiovascular magnetic resonance a prime role among all the noninvasive cardiovascular investigations. Late gadolinium enhancement imaging is an established method for visualizing replacement scar, providing diagnostic and prognostic information in a variety of cardiac conditions. Late gadolinium enhancement, however, relies on the regional segregation of tissue characteristics to generate the imaging contrast. Thus, myocardial pathology that is diffuse in nature and affecting the myocardium in a rather uniform and global distribution is not well visualized with late gadolinium enhancement. Examples include diffuse myocardial inflammation, fibrosis, hypertrophy, and infiltration. T1 mapping is a novel technique allowing to diagnose these diffuse conditions by measurement of T1 values, which directly correspond to variation in intrinsic myocardial tissue properties. In addition to providing clinically meaningful indices, T1-mapping measurements also allow for an estimation of extracellular space by calculation of extracellular volume fraction. Multiple lines of evidence suggest a central role for T1 mapping in detection of diffuse myocardial disease in early disease stages and complements late gadolinium enhancement in visualization of the regional changes in common advanced myocardial disease. As a quantifiable measure, it may allow grading of disease activity, monitoring progress, and guiding treatment, potentially as a fast contrast-free clinical application. We present an overview of clinically relevant technical aspects of acquisition and processing, and the current state of art and evidence, supporting its clinical use. © 2016 American Heart Association, Inc.

  13. Wideband Arrhythmia-Insensitive-Rapid (AIR) Pulse Sequence for Cardiac T1 mapping without Image Artifacts induced by ICD

    PubMed Central

    Hong, KyungPyo; Jeong, Eun-Kee; Wall, T. Scott; Drakos, Stavros G.; Kim, Daniel

    2015-01-01

    Purpose To develop and evaluate a wideband arrhythmia-insensitive-rapid (AIR) pulse sequence for cardiac T1 mapping without image artifacts induced by implantable-cardioverter-defibrillator (ICD). Methods We developed a wideband AIR pulse sequence by incorporating a saturation pulse with wide frequency bandwidth (8.9 kHz), in order to achieve uniform T1 weighting in the heart with ICD. We tested the performance of original and “wideband” AIR cardiac T1 mapping pulse sequences in phantom and human experiments at 1.5T. Results In 5 phantoms representing native myocardium and blood and post-contrast blood/tissue T1 values, compared with the control T1 values measured with an inversion-recovery pulse sequence without ICD, T1 values measured with original AIR with ICD were considerably lower (absolute percent error >29%), whereas T1 values measured with wideband AIR with ICD were similar (absolute percent error <5%). Similarly, in 11 human subjects, compared with the control T1 values measured with original AIR without ICD, T1 measured with original AIR with ICD was significantly lower (absolute percent error >10.1%), whereas T1 measured with wideband AIR with ICD was similar (absolute percent error <2.0%). Conclusion This study demonstrates the feasibility of a wideband pulse sequence for cardiac T1 mapping without significant image artifacts induced by ICD. PMID:25975192

  14. Saturation-inversion-recovery: A method for T1 measurement

    NASA Astrophysics Data System (ADS)

    Wang, Hongzhi; Zhao, Ming; Ackerman, Jerome L.; Song, Yiqiao

    2017-01-01

    Spin-lattice relaxation (T1) has always been measured by inversion-recovery (IR), saturation-recovery (SR), or related methods. These existing methods share a common behavior in that the function describing T1 sensitivity is the exponential, e.g., exp(- τ /T1), where τ is the recovery time. In this paper, we describe a saturation-inversion-recovery (SIR) sequence for T1 measurement with considerably sharper T1-dependence than those of the IR and SR sequences, and demonstrate it experimentally. The SIR method could be useful in improving the contrast between regions of differing T1 in T1-weighted MRI.

  15. Improved visibility of brain tumors in synthetic MP-RAGE anatomies with pure T1 weighting.

    PubMed

    Nöth, Ulrike; Hattingen, Elke; Bähr, Oliver; Tichy, Julia; Deichmann, Ralf

    2015-07-01

    Conventional MRI for brain tumor diagnosis employs T2 -weighted and contrast-enhanced T1 -weighted sequences. Non-enhanced T1 -weighted images provide improved anatomical details for precise tumor location, but reduced tumor-to-background contrast as elevated T1 and proton density (PD) values in tumor tissue affect the signal inversely. Radiofrequency (RF) coil inhomogeneities may further mask tumor and edema outlines. To overcome this problem, the aims of this work were to employ quantitative MRI techniques to create purely T1 -weighted synthetic anatomies which can be expected to yield improved tissue and tumor-to-background contrasts, to compare the quality of conventional and synthetic anatomies, and to investigate optical contrast and visibility of brain tumors and edema in synthetic anatomies. Conventional magnetization-prepared rapid acquisition of gradient echoes (MP-RAGE) anatomies and maps of T1 , PD and RF coil profiles were acquired in comparable and clinically feasible times. Three synthetic MP-RAGE anatomies (PD T1 weighting both with and without RF bias; pure T1 weighting) were calculated for healthy subjects and 32 patients with brain tumors. In healthy subjects, the PD T1 -weighted synthetic anatomies with RF bias precisely matched the conventional anatomies, yielding high signal-to-noise (SNR) and contrast-to-noise (CNR) ratios. Pure T1 weighting yielded lower SNR, but high CNR, because of increased optical contrasts. In patients with brain tumors, synthetic anatomies with pure T1 weighting yielded significant increases in optical contrast and improved visibility of tumor and edema in comparison with anatomies reflecting conventional T1 contrasts. In summary, the optimized purely T1 -weighted synthetic anatomy with an isotropic resolution of 1 mm, as proposed in this work, considerably enhances optical contrast and visibility of brain tumors and edema. Copyright © 2015 John Wiley & Sons, Ltd.

  16. Determination of T1 relaxation time of normal equine tendons using magic angle magnetic resonance imaging.

    PubMed

    Spriet, Mathieu; Wisner, Erik R; Anthenill, Lucy A; Buonocore, Michael H

    2011-01-01

    Seven isolated equine front limbs were used to establish the normal T1 relaxation time of equine superficial digital flexor tendon (SDFT), deep digital flexor tendon (DDFT), and suspensory ligament (SL) using magic angle magnetic resonance (MR) imaging. MR imaging of the metacarpi was performed with the limbs positioned at 55° (the magic angle) relative to the main magnetic field. Transverse spin-echo proton density and inversion recovery images were acquired. T1 relaxation time was calculated based on ratios of signal intensity determined from the different pulse sequences. T1 relaxation times for SDFT, DDFT, and SL were 288 (± 17), 244 (± 14), and 349 (± 16) ms, respectively. The difference in T1 values between SDFT, DDFT, and SL was statistically significant. T1 values of equine tendons can be determined with magic angle imaging on a clinical MR system using < 10 min total scan time. The knowledge of the normal range of T1 values may be useful to identify horses with chronic tendinopathy, where based on the human literature, an increased T1 value may be expected. © 2010 Veterinary Radiology & Ultrasound.

  17. Fast MAS 1H NMR Study of Water Adsorption and Dissociation on the (100) Surface of Ceria Nanocubes: A Fully Hydroxylated, Hydrophobic Ceria Surface

    DOE PAGES

    Gill, Lance; Beste, Ariana; Chen, Banghao; ...

    2017-03-22

    1H nuclear magnetic resonance (NMR) spectroscopy was used to study hydroxylic surface species on ceria nanocubes, a crystalline, high-surface-area CeO2 that presents mostly (100) facets. Water adsorption and desorption experiments in combination with fast magic angle spinning (MAS, 20–40 kHz) 1H NMR provide high-resolution 1H spectra that allow the observation of ten resonance bands (water or hydroxyl) on or under the (100) surface. Assignments were made using a combination of adsorption and temperature-programmed desorption, quantitative spin counting, deuterium exchange, spin–lattice (T1) and spin–spin (T2) relaxation, and DFT calculations. In air, the (100) surface exists as a fully hydroxylated surface. Watermore » adsorption and dissociation on dry ceria surfaces occur first at oxygen vacancies, but Ce3+ centers are not required since water dissociation is barrier-less on the fully oxidized surface. Surface $-$OH functionality occurs in two resolved bands representing isolated $-$OH (1 ppm) and hydrogen-bonded $-$OH (9 ppm), the latter being dominant. Deuterium exchange of surface hydroxyls with D2O does not occur under mild or forcing conditions. Despite large differences in the T1 of surface hydroxyls and physisorbed water, surface hydroxyl T1 values are independent of the presence or absence of physisorbed water, demonstrating that the protons within these two functional group pools are not in intimate contact. These observations show that, once hydroxylated, the surface $-$OH functionality preferentially forms hydrogen bonds with surface lattice oxygen, i.e., the hydroxylated (100) surface of ceria is hydrophobic. Near this surface it is energetically more favorable for physisorbed water to hydrogen bond to itself rather than to the surface. DFT calculations support this notion. Impurity Na+ remaining in incompletely washed ceria nanocubes increases the surface hydrophilicity. In conclusion, sharp, low-field resonances observed in spectra of

  18. White matter and lesion T1 relaxation times increase in parallel and correlate with disability in multiple sclerosis.

    PubMed

    Parry, A; Clare, S; Jenkinson, M; Smith, S; Palace, J; Matthews, P M

    2002-09-01

    Previous studies have established the clinical relevance of hypointense lesions ("black holes") on T1-weighted MRI as a surrogate marker for pathological change [36]. In contrast to measuring the volume of "black holes", the direct measurement of T1 values allows an objective assessment of the changes contributing to hypointensity both in the focal lesions and in the normal appearing white matter (NAWM). The aims of this study were first, to determine the relationship between T1 values in the NAWM and in discrete lesions, second, to test the relationship between white matter T1 changes and measures of disability and third, to determine whether pathology leading to T1 change occurred in thalamic grey matter of patients with multiple sclerosis. 24 patients with clinically definite multiple sclerosis (13 with relapsing-remitting multiple sclerosis and 11 with secondary progressive multiple sclerosis) and 11 controls participated. White matter T1 histograms and mean T1 values for the thalamus were generated from whole brain T1 relaxation time maps measured using a novel echo-planar imaging based MRI sequence at 3Tesla. Tissue segmentation based on T2- and T1-weighted images allowed independent study of changes in lesions and NAWM. White matter T1 histograms from the patient group showed a reduced peak height and a shift towards higher T1 values (p = 0.028) relative to controls. The mean thalamic T1 was greater for secondary progressive patients than for healthy controls (p = 0.03). Mean white matter T1 values correlated significantly with disability (r = 0.48, p = 0.02). The mean T1 value in the T1-hypointense lesions correlated strongly with the mean T1 value in the NAWM (r = 0.80, p < 0.001). No significant relationship was found between mean white matter T1 value and cerebral volume (r = -0.23, p = 0.31). The T1 measurements extend previous observations suggesting that changes in the NAWM occur in parallel with pathology in lesions of MS. T1 measurements of either

  19. Increasing 14N NQR signal by 1H-14N level crossing with small magnetic fields.

    PubMed

    Thurber, Kent R; Sauer, Karen L; Buess, Michael L; Klug, Christopher A; Miller, Joel B

    2005-11-01

    NQR detection of materials, such as TNT, is hindered by the low signal-to-noise ratio at low NQR frequencies. Sweeping small (0-26 mT) magnetic fields to shift the (1)H NMR frequency relative to the (14)N NQR frequencies can provide a significant increase of the (14)N NQR signal-to-noise ratio. Three effects of (1)H-(14)N level crossing are demonstrated in diglycine hydrochloride and TNT. These effects are (1) transferring (1)H polarization to one or more of the (14)N transitions, including the use of an adiabatic flip of the (1)H polarization during the field sweep, (2) shortening the effective (14)N T(1) by the interaction of (1)H with the (14)N transitions, (3) "level transfer" effect where the third (14)N (spin 1) energy level or other (14)N sites with different NQR frequency are used as a reservoir of polarization which is transferred to the measured (14)N transition by the (1)H. The (14)N NQR signal-to-noise ratio can be increased by a factor of 2.5 for one (14)N site in diglycine hydrochloride (and 2.2 in TNT), even though the maximum (1)H frequency used in this work, 111 6 kHz, is only 30% larger than the measured (14)N frequencies (834 kHz for diglycine hydrochloride and 843 kHz for TNT).

  20. Measurement of myocardial native T1 in cardiovascular diseases and norm in 1291 subjects.

    PubMed

    Liu, Joanna M; Liu, Alexander; Leal, Joana; McMillan, Fiona; Francis, Jane; Greiser, Andreas; Rider, Oliver J; Myerson, Saul; Neubauer, Stefan; Ferreira, Vanessa M; Piechnik, Stefan K

    2017-09-28

    Native T1-mapping provides quantitative myocardial tissue characterization for cardiovascular diseases (CVD), without the need for gadolinium. However, its translation into clinical practice is hindered by differences between techniques and the lack of established reference values. We provide typical myocardial T1-ranges for 18 commonly encountered CVDs using a single T1-mapping technique - Shortened Look-Locker Inversion Recovery (ShMOLLI), also used in the large UK Biobank and Hypertrophic Cardiomyopathy Registry study. We analyzed 1291 subjects who underwent CMR (1.5-Tesla, MAGNETOM-Avanto, Siemens Healthcare, Erlangen, Germany) between 2009 and 2016, who had a single CVD diagnosis, with mid-ventricular T1-map assessment. A region of interest (ROI) was placed on native T1-maps in the "most-affected myocardium", characterized by the presence of late gadolinium enhancement (LGE), or regional wall motion abnormalities (RWMA) on cines. Another ROI was placed in the "reference myocardium" as far as possible from LGE/RWMA, and in the septum if no focal abnormality was present. To further define normality, we included native T1 of healthy subjects from an existing dataset after sub-endocardial pixel-erosions. Native T1 of patients with normal CMR (938 ± 21 ms) was similar compared to healthy subjects (941 ± 23 ms). Across all patient groups (57 ± 19 yrs., 65% males), focally affected myocardium had significantly different T1 value compared to reference myocardium (all p < 0.001). In the affected myocardium, cardiac amyloidosis (1119 ± 61 ms) had the highest native T1 compared to normal and all other CVDs, while iron-overload (795 ± 58 ms) and Anderson-Fabry disease (863 ± 23 ms) had the lowest native reference T1 (all p < 0.001). Future studies designed to detect the large T1 differences between affected and reference myocardium are estimated to require small sample-sizes (n < 50). However, studies designed to detect the small T1

  1. T1- Thresholds in Black Holes Increase Clinical-Radiological Correlation in Multiple Sclerosis Patients

    PubMed Central

    Thaler, Christian; Faizy, Tobias; Sedlacik, Jan; Holst, Brigitte; Stellmann, Jan-Patrick; Young, Kim Lea; Heesen, Christoph; Fiehler, Jens; Siemonsen, Susanne

    2015-01-01

    Background Magnetic Resonance Imaging (MRI) is an established tool in diagnosing and evaluating disease activity in Multiple Sclerosis (MS). While clinical-radiological correlations are limited in general, hypointense T1 lesions (also known as Black Holes (BH)) have shown some promising results. The definition of BHs is very heterogeneous and depends on subjective visual evaluation. Objective We aimed to improve clinical-radiological correlations by defining BHs using T1 relaxation time (T1-RT) thresholds to achieve best possible correlation between BH lesion volume and clinical disability. Method 40 patients with mainly relapsing-remitting MS underwent MRI including 3-dimensional fluid attenuated inversion recovery (FLAIR), magnetization-prepared rapid gradient echo (MPRAGE) before and after Gadolinium (GD) injection and double inversion-contrast magnetization-prepared rapid gradient echo (MP2RAGE) sequences. BHs (BHvis) were marked by two raters on native T1-weighted (T1w)-MPRAGE, contrast-enhancing lesions (CE lesions) on T1w-MPRAGE after GD and FLAIR lesions (total-FLAIR lesions) were detected separately. BHvis and total-FLAIR lesion maps were registered to MP2RAGE images, and the mean T1-RT were calculated for all lesion ROIs. Mean T1 values of the cortex (CTX) were calculated for each patient. Subsequently, Spearman rank correlations between clinical scores (Expanded Disability Status Scale and Multiple Sclerosis Functional Composite) and lesion volume were determined for different T1-RT thresholds. Results Significant differences in T1-RT were obtained between all different lesion types with highest T1 values in visually marked BHs (BHvis: 1453.3±213.4 ms, total-FLAIR lesions: 1394.33±187.38 ms, CTX: 1305.6±35.8 ms; p<0.05). Significant correlations between BHvis/total-FLAIR lesion volume and clinical disability were obtained for a wide range of T1-RT thresholds. The highest correlation for BHvis and total-FLAIR lesion masks were found at T1-RT>1500 ms

  2. T1- Thresholds in Black Holes Increase Clinical-Radiological Correlation in Multiple Sclerosis Patients.

    PubMed

    Thaler, Christian; Faizy, Tobias; Sedlacik, Jan; Holst, Brigitte; Stellmann, Jan-Patrick; Young, Kim Lea; Heesen, Christoph; Fiehler, Jens; Siemonsen, Susanne

    2015-01-01

    Magnetic Resonance Imaging (MRI) is an established tool in diagnosing and evaluating disease activity in Multiple Sclerosis (MS). While clinical-radiological correlations are limited in general, hypointense T1 lesions (also known as Black Holes (BH)) have shown some promising results. The definition of BHs is very heterogeneous and depends on subjective visual evaluation. We aimed to improve clinical-radiological correlations by defining BHs using T1 relaxation time (T1-RT) thresholds to achieve best possible correlation between BH lesion volume and clinical disability. 40 patients with mainly relapsing-remitting MS underwent MRI including 3-dimensional fluid attenuated inversion recovery (FLAIR), magnetization-prepared rapid gradient echo (MPRAGE) before and after Gadolinium (GD) injection and double inversion-contrast magnetization-prepared rapid gradient echo (MP2RAGE) sequences. BHs (BHvis) were marked by two raters on native T1-weighted (T1w)-MPRAGE, contrast-enhancing lesions (CE lesions) on T1w-MPRAGE after GD and FLAIR lesions (total-FLAIR lesions) were detected separately. BHvis and total-FLAIR lesion maps were registered to MP2RAGE images, and the mean T1-RT were calculated for all lesion ROIs. Mean T1 values of the cortex (CTX) were calculated for each patient. Subsequently, Spearman rank correlations between clinical scores (Expanded Disability Status Scale and Multiple Sclerosis Functional Composite) and lesion volume were determined for different T1-RT thresholds. Significant differences in T1-RT were obtained between all different lesion types with highest T1 values in visually marked BHs (BHvis: 1453.3±213.4 ms, total-FLAIR lesions: 1394.33±187.38 ms, CTX: 1305.6±35.8 ms; p<0.05). Significant correlations between BHvis/total-FLAIR lesion volume and clinical disability were obtained for a wide range of T1-RT thresholds. The highest correlation for BHvis and total-FLAIR lesion masks were found at T1-RT>1500 ms (Expanded Disability Status Scale vs

  3. Complete (1) H NMR assignment of cedranolides.

    PubMed

    Perez-Hernandez, Nury; Gordillo-Roman, Barbara; Arrieta-Baez, Daniel; Cerda-Garcia-Rojas, Carlos M; Joseph-Nathan, Pedro

    2017-03-01

    Complete and unambiguous (1) H NMR chemical shift assignment of α-cedrene (2) and cedrol (9), as well as for α-pipitzol (1), isocedrol (10), and the six related compounds 3-8 has been established by iterative full spin analysis using the PERCH NMR software (PERCH Solutions Ltd., Kuopio, Finland). The total sets of coupling constants are described and correlated with the conformational equilibria of the five-membered ring of 1-10, which were calculated using the complete basis set method. Copyright © 2015 John Wiley & Sons, Ltd.

  4. Orosensory detection of sucrose, maltose, and glucose is severely impaired in mice lacking T1R2 or T1R3, but Polycose sensitivity remains relatively normal.

    PubMed

    Treesukosol, Yada; Spector, Alan C

    2012-07-15

    Evidence in the literature supports the hypothesis that the T1R2+3 heterodimer binds to compounds that humans describe as sweet. Here, we assessed the necessity of the T1R2 and T1R3 subunits in the maintenance of normal taste sensitivity to carbohydrate stimuli. We trained and tested water-restricted T1R2 knockout (KO), T1R3 KO and their wild-type (WT) same-sex littermate controls in a two-response operant procedure to sample a fluid and differentially respond on the basis of whether the stimulus was water or a tastant. Correct responses were reinforced with water and incorrect responses were punished with a time-out. Testing was conducted with a modified descending method of limits procedure across daily 25-min sessions. Both KO groups displayed severely impaired performance and markedly decreased sensitivity when required to discriminate water from sucrose, glucose, or maltose. In contrast, when Polycose was tested, KO mice had normal EC(50) values for their psychometric functions, with some slight, but significant, impairment in performance. Sensitivity to NaCl did not differ between these mice and their WT controls. Our findings support the view that the T1R2+3 heterodimer is the principal receptor that mediates taste detection of natural sweeteners, but not of all carbohydrate stimuli. The combined presence of T1R2 and T1R3 appears unnecessary for the maintenance of relatively normal sensitivity to Polycose, at least in this task. Some detectability of sugars at high concentrations might be mediated by the putative polysaccharide taste receptor, the remaining T1R subunit forming either a homodimer or heteromer with another protein(s), or nontaste orosensory cues.

  5. Orosensory detection of sucrose, maltose, and glucose is severely impaired in mice lacking T1R2 or T1R3, but Polycose sensitivity remains relatively normal

    PubMed Central

    Treesukosol, Yada

    2012-01-01

    Evidence in the literature supports the hypothesis that the T1R2+3 heterodimer binds to compounds that humans describe as sweet. Here, we assessed the necessity of the T1R2 and T1R3 subunits in the maintenance of normal taste sensitivity to carbohydrate stimuli. We trained and tested water-restricted T1R2 knockout (KO), T1R3 KO and their wild-type (WT) same-sex littermate controls in a two-response operant procedure to sample a fluid and differentially respond on the basis of whether the stimulus was water or a tastant. Correct responses were reinforced with water and incorrect responses were punished with a time-out. Testing was conducted with a modified descending method of limits procedure across daily 25-min sessions. Both KO groups displayed severely impaired performance and markedly decreased sensitivity when required to discriminate water from sucrose, glucose, or maltose. In contrast, when Polycose was tested, KO mice had normal EC50 values for their psychometric functions, with some slight, but significant, impairment in performance. Sensitivity to NaCl did not differ between these mice and their WT controls. Our findings support the view that the T1R2+3 heterodimer is the principal receptor that mediates taste detection of natural sweeteners, but not of all carbohydrate stimuli. The combined presence of T1R2 and T1R3 appears unnecessary for the maintenance of relatively normal sensitivity to Polycose, at least in this task. Some detectability of sugars at high concentrations might be mediated by the putative polysaccharide taste receptor, the remaining T1R subunit forming either a homodimer or heteromer with another protein(s), or nontaste orosensory cues. PMID:22621968

  6. T1 and susceptibility contrast at high fields

    NASA Astrophysics Data System (ADS)

    Neelavalli, Jaladhar

    Clinical imaging at high magnetic field strengths (≥ 3Tesla) is sought after primarily due to the increased signal strength available at these fields. This increased SNR can be used to perform: (a) high resolution imaging in the same time as at lower field strengths; (b) the same resolution imaging with much faster acquisition; and (c) functional MR imaging (fMRI), dynamic perfusion and diffusion imaging with increased sensitivity. However they are also associated with increased power deposition (SAR) due to increase in imaging frequency and longer T1 relaxation times. Longer T1s mean longer imaging times for generating good T1 contrast images. On the other hand for faster imaging, at high fields fast spin echo or magnetization prepared sequences are conventionally proposed which are, however, associated with high SAR values. Imaging with low SAR is more and more important as we move towards high fields and particularly for patients with metallic implants like pacemakers or deep brain stimulator. The SAR limit acceptable for these patients is much less than the limit acceptable for normal subjects. A new method is proposed for imaging at high fields with good contrast with simultaneous reduction in power deposition. Further, T1 based contrast optimization problem in FLASH imaging is considered for tissues with different T1s but same spin densities. The solution providing optimal imaging parameters is simplified for quick and easy computation in a clinical setting. The efficacy of the simplification is evaluated and practical limits under which the simplification can be applied are worked out. The phase difference due to variation in magnetic susceptibility property among biological tissues is another unique source of contrast which is different from the conventional T1, T2 and T2* contrast. This susceptibility based phase contrast has become more and more important at high fields, partly due to contrast generation issues due to longer T 1s and shorter T2s and

  7. T1rho MRI and CSF biomarkers in diagnosis of Alzheimer's disease.

    PubMed

    Haris, Mohammad; Yadav, Santosh K; Rizwan, Arshi; Singh, Anup; Cai, Kejia; Kaura, Deepak; Wang, Ena; Davatzikos, Christos; Trojanowski, John Q; Melhem, Elias R; Marincola, Francesco M; Borthakur, Arijitt

    2015-01-01

    In the current study, we have evaluated the performance of magnetic resonance (MR) T1rho (T1ρ) imaging and CSF biomarkers (T-tau, P-tau and Aβ-42) in characterization of Alzheimer's disease (AD) patients from mild cognitive impairment (MCI) and control subjects. With informed consent, AD (n = 27), MCI (n = 17) and control (n = 17) subjects underwent a standardized clinical assessment and brain MRI on a 1.5-T clinical-scanner. T1ρ images were obtained at four different spin-lock pulse duration (10, 20, 30 and 40 ms). T1ρ maps were generated by pixel-wise fitting of signal intensity as a function of the spin-lock pulse duration. T1ρ values from gray matter (GM) and white matter (WM) of medial temporal lobe were calculated. The binary logistic regression using T1ρ and CSF biomarkers as variables was performed to classify each group. T1ρ was able to predict 77.3% controls and 40.0% MCI while CSF biomarkers predicted 81.8% controls and 46.7% MCI. T1ρ and CSF biomarkers in combination predicted 86.4% controls and 66.7% MCI. When comparing controls with AD, T1ρ predicted 68.2% controls and 73.9% AD, while CSF biomarkers predicted 77.3% controls and 78.3% for AD. Combination of T1ρ and CSF biomarkers improved the prediction rate to 81.8% for controls and 82.6% for AD. Similarly, on comparing MCI with AD, T1ρ predicted 35.3% MCI and 81.9% AD, whereas CSF biomarkers predicted 53.3% MCI and 83.0% AD. Collectively CSF biomarkers and T1ρ were able to predict 59.3% MCI and 84.6% AD. On receiver operating characteristic analysis T1ρ showed higher sensitivity while CSF biomarkers showed greater specificity in delineating MCI and AD from controls. No significant correlation between T1ρ and CSF biomarkers, between T1ρ and age, and between CSF biomarkers and age was observed. The combined use of T1ρ and CSF biomarkers have promise to improve the early and specific diagnosis of AD. Furthermore, disease progression form MCI to AD might be easily tracked using

  8. 1H Magnetic Resonance Spectroscopy of live human sperm.

    PubMed

    Reynolds, S; Calvert, S J; Paley, M N; Pacey, A A

    2017-07-01

    Can 1H Magnetic Resonance Spectroscopy (MRS) be used to obtain information about the molecules and metabolites in live human spermatozoa? Percoll-based density gradient centrifugation (DGC) followed by a further two washing steps, yielded enough sperm with minimal contamination (<0.01%) from seminal fluid to permit effective MRS which detected significant differences (P < 0.05) in the choline/glycerophosphocholine (GPC), lipid and lactate regions of the 1H MRS spectrum between sperm in the pellet and those from the 40%/80% interface. Current methods to examine sperm are either limited in their value (e.g. semen analysis) or are destructive (e.g. immunohistochemistry, sperm DNA testing). A few studies have previously used MRS to examine sperm, but these have either looked at seminal plasma from men with different ejaculate qualities or at the molecules present in pooled samples of lyophilized sperm. Sperm suspended in phosphate buffered saline (PBS) at 37°C were examined by 1H MRS scanning using a 1H excitation-sculpting solvent suppression sequence after recovery from fresh ejaculates by one of three different methods: (i) simple centrifugation; (ii) DGC with one wash; or (iii) DGC with two washes. In the case of DGC, sperm were collected both from the pellet ('80%' sperm) and the 40/80 interface ('40%' sperm). Spectrum processing was carried out using custom Matlab scripts to determine; the degree of seminal plasma/Percoll contamination, the minimum sperm concentration for 1H MRS detection and differences between the 1H MRS spectra of '40%' and '80%' sperm. DGC with two washes minimized the 1H MRS peak intensity for both seminal plasma and Percoll/PBS solution contamination while retaining sperm specific peaks. For the MRS scanner used in this study, the minimum sperm concentration required to produce a choline/GPC 1H MRS peak greater than 3:1 signal to noise ratio (SNR) was estimated at ~3 × 106/ml. The choline/GPC and lactate/lipid regions of the 1H spectrum

  9. Differentiation of brain tumor-related edema based on 3D T1rho imaging.

    PubMed

    Villanueva-Meyer, J E; Barajas, R F; Mabray, M C; Chen, W; Shankaranarayanan, A; Koon, P; Barani, I J; Tihan, T; Cha, S

    2017-06-01

    Cerebral edema associated with brain tumors is an important source of morbidity. Its type depends largely on the capillary ultra-structures of the histopathologic subtype of underlying brain tumor. The purpose of our study was to differentiate vasogenic edema associated with brain metastases and infiltrative edema related to diffuse gliomas using quantitative 3D T1 rho (T1ρ) imaging. Preoperative MR examination including whole brain 3D T1ρ imaging was performed in 23 patients with newly diagnosed brain tumors (9 with metastasis, 8 with lower grade glioma, LGG, 6 with glioblastoma, GBM). Mean T1ρ values were measured in regions of peritumoral non-enhancing T2 signal hyperintensity, excluding both enhancing and necrotic or cystic component, and normal-appearing white matter. Mean T1ρ values were significantly elevated in the vasogenic edema surrounding intracranial metastases when compared to the infiltrative edema associated with either LGG or GBM (p=0.02 and <0.01, respectively). No significant difference was noted between T1ρ values of infiltrative edema between LGG and GBM (p=0.84 and 0.96, respectively). Our study demonstrates the feasibility and potential diagnostic role of T1ρ in the quantitative differentiation between edema related to intracranial metastases and gliomas and as a potentially complementary tool to standard MR techniques in further characterizing pathophysiology of vasogenic and infiltrative edema. Copyright © 2017. Published by Elsevier B.V.

  10. Rapid measurement of multidimensional 1H solid-state NMR spectra at ultra-fast MAS frequencies

    NASA Astrophysics Data System (ADS)

    Ye, Yue Qi; Malon, Michal; Martineau, Charlotte; Taulelle, Francis; Nishiyama, Yusuke

    2014-02-01

    A novel method to realize rapid repetition of 1H NMR experiments at ultra-fast MAS frequencies is demonstrated. The ultra-fast MAS at 110 kHz slows the 1H-1H spin diffusion, leading to variations of 1H T1 relaxation times from atom to atom within a molecule. The different relaxation behavior is averaged by applying 1H-1H recoupling during relaxation delay even at ultra-fast MAS, reducing the optimal relaxation delay to maximize the signal to noise ratio. The way to determine optimal relaxation delay for arbitrary relaxation curve is shown. The reduction of optimal relaxation delay by radio-frequency driven recoupling (RFDR) was demonstrated on powder samples of glycine and ethenzamide with one and multi-dimensional NMR measurements.

  11. T1-/T2-weighted ratio differs in demyelinated cortex of multiple sclerosis.

    PubMed

    Nakamura, Kunio; Chen, Jacqueline T; Ontaneda, Daniel; Fox, Robert J; Trapp, Bruce D

    2017-08-18

    Detecting cortical demyelination in patients with multiple sclerosis (MS) is difficult. Using magnetic resonance imaging (MRI), ratio maps of T1-weighted and T2-weighted images (T1w/T2w) may be sensitive to cortical myelin levels. In this MRI-histological study, postmortem in situ scans were acquired from six cadavers with MS on a 3 Tesla MRI. Immunocytochemistry was used to correlate myelin status and cortical T1w/T2w measures. The results showed that the T1w/T2w values significantly differed between demyelinated and myelinated cortex (p < 0.001). The T1w/T2w ratio maps may be a relatively simple, clinically feasible method to assess cortical demyelination. This article is protected by copyright. All rights reserved. © 2017 American Neurological Association.

  12. T 1 Relaxation Measurement of Ex-Vivo Breast Cancer Tissues at Ultralow Magnetic Fields

    PubMed Central

    Lee, Seong-Joo; Shim, Jeong Hyun; Kim, Kiwoong; Hwang, Seong-min; Yu, Kwon Kyu; Lim, Sanghyun; Han, Jae Ho; Yim, Hyunee; Kim, Jang-Hee; Jung, Yong Sik; Kim, Ku Sang

    2015-01-01

    We investigated T1 relaxations of ex-vivo cancer tissues at low magnetic fields in order to check the possibility of achieving a T1 contrast higher than those obtained at high fields. The T1 relaxations of fifteen pairs (normal and cancerous) of breast tissue samples were measured at three magnetic fields, 37, 62, and 122 μT, using our superconducting quantum interference device-based ultralow field nuclear magnetic resonance setup, optimally developed for ex-vivo tissue studies. A signal reconstruction based on Bayesian statistics for noise reduction was exploited to overcome the low signal-to-noise ratio. The ductal and lobular-type tissues did not exhibit meaningful T1 contrast values between normal and cancerous tissues at the three different fields. On the other hand, an enhanced T1 contrast was obtained for the mucinous cancer tissue. PMID:25705658

  13. Spatial Distribution and Relationship of T1ρ and T2 Relaxation Times in Knee Cartilage With Osteoarthritis

    PubMed Central

    Li, Xiaojuan; Pai, Alex; Blumenkrantz, Gabrielle; Carballido-Gamio, Julio; Link, Thomas; Ma, Benjamin; Ries, Michael; Majumdar, Sharmila

    2009-01-01

    T1ρ and T2 relaxation time constants have been proposed to probe biochemical changes in osteoarthritic cartilage. This study aimed to evaluate the spatial correlation and distribution of T1ρ and T2 values in osteoarthritic cartilage. Ten patients with osteoarthritis (OA) and 10 controls were studied at 3T. The spatial correlation of T1ρ and T2 values was investigated using Z-scores. The spatial variation of T1ρ and T2 values in patellar cartilage was studied in different cartilage layers. The distribution of these relaxation time constants was measured using texture analysis parameters based on gray-level co-occurrence matrices (GLCM). The mean Z-scores for T1ρ and T2 values were significantly higher in OA patients vs. controls (P < 0.05). Regional correlation coefficients of T1ρ and T2 Z-scores showed a large range in both controls and OA patients (0.2– 0.7). OA patients had significantly greater GLCM contrast and entropy of T1ρ values than controls (P < 0.05). In summary, T1ρ and T2 values are not only increased but are also more heterogeneous in osteoarthritic cartilage. T1ρ and T2 values show different spatial distributions and may provide complementary information regarding cartilage degeneration in OA. PMID:19319904

  14. Improving Assessment of Lipoprotein Profile in Type 1 Diabetes by 1H NMR Spectroscopy

    PubMed Central

    Brugnara, Laura; Mallol, Roger; Ribalta, Josep; Vinaixa, Maria; Murillo, Serafín; Casserras, Teresa; Guardiola, Montse; Vallvé, Joan Carles; Kalko, Susana G.; Correig, Xavier; Novials, Anna

    2015-01-01

    Patients with type 1 diabetes (T1D) present increased risk of cardiovascular disease (CVD). The aim of this study is to improve the assessment of lipoprotein profile in patients with T1D by using a robust developed method 1H nuclear magnetic resonance spectroscopy (1H NMR), for further correlation with clinical factors associated to CVD. Thirty patients with T1D and 30 non-diabetes control (CT) subjects, matched for gender, age, body composition (DXA, BMI, waist/hip ratio), regular physical activity levels and cardiorespiratory capacity (VO2peak), were analyzed. Dietary records and routine lipids were assessed. Serum lipoprotein particle subfractions, particle sizes, and cholesterol and triglycerides subfractions were analyzed by 1H NMR. It was evidenced that subjects with T1D presented lower concentrations of small LDL cholesterol, medium VLDL particles, large VLDL triglycerides, and total triglycerides as compared to CT subjects. Women with T1D presented a positive association with HDL size (p<0.005; R = 0.601) and large HDL triglycerides (p<0.005; R = 0.534) and negative (p<0.005; R = -0.586) to small HDL triglycerides. Body fat composition represented an important factor independently of normal BMI, with large LDL particles presenting a positive correlation to total body fat (p<0.005; R = 0.505), and total LDL cholesterol and small LDL cholesterol a positive correlation (p<0.005; R = 0.502 and R = 0.552, respectively) to abdominal fat in T1D subjects; meanwhile, in CT subjects, body fat composition was mainly associated to HDL subclasses. VO2peak was negatively associated (p<0.005; R = -0.520) to large LDL-particles only in the group of patients with T1D. In conclusion, patients with T1D with adequate glycemic control and BMI and without chronic complications presented a more favourable lipoprotein profile as compared to control counterparts. In addition, slight alterations in BMI and/or body fat composition showed to be relevant to provoking alterations in

  15. Measurement of T1 relaxation time of osteochondral specimens using VFA-SWIFT

    PubMed Central

    Nissi, M. J.; Lehto, L. J.; Corum, C.A.; Idiyatullin, D.; Ellermann, J. M.; Gröhn, O. H. J.; Nieminen, M. T.

    2015-01-01

    Purpose To evaluate the feasibility of SWIFT with variable flip angle (VFA) for measurement of T1 relaxation time in Gd-agarose-phantoms and osteochondral specimens, including regions of very short T2*, and compare with T1 measured using standard methods. Methods T1s of agarose phantoms with variable concentration of Gd-DTPA2− and nine pairs of native and trypsin-treated bovine cartilage-bone specimens were measured. For specimens, VFA-SWIFT, inversion recovery (IR) fast spin echo (FSE) and saturation recovery FSE were used. For phantoms, additionally spectroscopic IR was used. Differences and agreement between the methods were assessed using non-parametric Wilcoxon and Kruskal-Wallis tests and intra-class correlation. Results The different T1 mapping methods agreed well in the phantoms. VFA-SWIFT allowed reliable measurement of T1 in the osteochondral specimens, including regions where FSE-based methods failed. The T1s measured by VFA-SWIFT were shifted towards shorter values in specimens. However, the measurements correlated significantly (highest correlation VFA-SWIFT vs. FSE was r=0.966). SNR efficiency was generally highest for SWIFT, especially in the subchondral bone. Conclusion Feasibility of measuring T1 relaxation time using VFA-SWIFT in osteochondral specimens and phantoms was demonstrated. A shift towards shorter T1s was observed for VFA-SWIFT in specimens, reflecting the higher sensitivity of SWIFT to short T2* spins. PMID:25111731

  16. T1 and T2 Mapping in Cardiology: "Mapping the Obscure Object of Desire".

    PubMed

    Mavrogeni, Sophie; Apostolou, Dimitris; Argyriou, Panayiotis; Velitsista, Stella; Papa, Lilika; Efentakis, Stelios; Vernardos, Evangelos; Kanoupaki, Mikela; Kanoupakis, George; Manginas, Athanassios

    2017-08-17

    The increasing use of cardiovascular magnetic resonance (CMR) is based on its capability to perform biventricular function assessment and tissue characterization without radiation and with high reproducibility. The use of late gadolinium enhancement (LGE) gave the potential of non-invasive biopsy for fibrosis quantification. However, LGE is unable to detect diffuse myocardial disease. Native T1 mapping and extracellular volume fraction (ECV) provide knowledge about pathologies affecting both the myocardium and interstitium that is otherwise difficult to identify. Changes of myocardial native T1 reflect cardiac diseases (acute coronary syndromes, infarction, myocarditis, and diffuse fibrosis, all with high T1) and systemic diseases such as cardiac amyloid (high T1), Anderson-Fabry disease (low T1), and siderosis (low T1). The ECV, an index generated by native and post-contrast T1 mapping, measures the cellular and extracellular interstitial matrix (ECM) compartments. This myocyte-ECM dichotomy has important implications for identifying specific therapeutic targets of great value for heart failure treatment. On the other hand, T2 mapping is superior compared with myocardial T1 and ECM for assessing the activity of myocarditis in recent-onset heart failure. Although these indices can significantly affect the clinical decision making, multicentre studies and a community-wide approach (including MRI vendors, funding, software, contrast agent manufacturers, and clinicians) are still missing. © 2017 S. Karger AG, Basel.

  17. Joint Brain Parametric T1-Map Segmentation and RF Inhomogeneity Calibration

    PubMed Central

    Chen, Ping-Feng; Steen, R. Grant; Yezzi, Anthony; Krim, Hamid

    2009-01-01

    We propose a constrained version of Mumford and Shah's (1989) segmentation model with an information-theoretic point of view in order to devise a systematic procedure to segment brain magnetic resonance imaging (MRI) data for parametric T1-Map and T1-weighted images, in both 2-D and 3D settings. Incorporation of a tuning weight in particular adds a probabilistic flavor to our segmentation method, and makes the 3-tissue segmentation possible. Moreover, we proposed a novel method to jointly segment the T1-Map and calibrate RF Inhomogeneity (JSRIC). This method assumes the average T1 value of white matter is the same across transverse slices in the central brain region, and JSRIC is able to rectify the flip angles to generate calibrated T1-Maps. In order to generate an accurate T1-Map, the determination of optimal flip-angles and the registration of flip-angle images are examined. Our JSRIC method is validated on two human subjects in the 2D T1-Map modality and our segmentation method is validated by two public databases, BrainWeb and IBSR, of T1-weighted modality in the 3D setting. PMID:19710938

  18. T1rho Magnetic Resonance Imaging at 3T Detects Knee Cartilage Changes After Viscosupplementation.

    PubMed

    Shah, Roshan P; Stambough, Jeffrey B; Fenty, Matthew; Mauck, Robert L; Kelly, John D; Reddy, Ravinder; Tjoumakaris, Fotios P

    2015-07-01

    Viscosupplementation may affect cartilage. Changes in T1rho magnetic resonance imaging (MRI) relaxation times correlate with proteoglycan changes in cartilage. The authors hypothesized that T1rho MRI will show an improvement in proteoglycan content at 6 weeks and 3 months after viscosupplementation and that this improvement will correlate with functional outcome scores. Ten patients (mean age, 56 years; Kellgren-Lawrence grade 1 or 2) underwent T1rho MRI at baseline, 6 weeks, and 3 months after viscosupplementation. Volumetric T1rho means were calculated by depth and region. Visual analog scale (VAS), International Knee Documentation Committee (IKDC), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were obtained. Mean T1rho values decreased in the superficial patella at 6 weeks (10.3%, P=.002) and 3 months (7.9%, P=.018) and in the middle patella at 6 weeks (7.0%, P=.014) compared with baseline values. Deep patella T1rho values increased at 3 months compared with 6 weeks (9.9%, P=.033), returning to values similar to baseline. Mean T1rho values increased in the deep tibia at 6 weeks (4.7%, P=.048) and in the middle tibia (5.2%, P=.004) and deep tibia (11.2%, P=.002) at 3 months compared with baseline. At 6 weeks, improvement was seen in VAS (5.9 to 3.9, P<.01), IKDC-9 (55.3 to 63.7, P=.03), and WOMAC (43.9 to 32.8, P=.03) scores. Functional VAS (4.0, P=.02), IKDC-9 (67.8, P=.04), and WOMAC (30.0, P=.04) scores remained better at 3 months. T1rho MRI is a feasible noninvasive method of studying molecular changes in cartilage. Some segments improved after viscosupplementation, and others worsened, possibly reflecting natural history or symptom relief and subsequent increase in activity-related wear.

  19. Saturation pulse design for quantitative myocardial T1 mapping.

    PubMed

    Chow, Kelvin; Kellman, Peter; Spottiswoode, Bruce S; Nielles-Vallespin, Sonia; Arai, Andrew E; Salerno, Michael; Thompson, Richard B

    2015-10-01

    Quantitative saturation-recovery based T1 mapping sequences are less sensitive to systematic errors than the Modified Look-Locker Inversion recovery (MOLLI) technique but require high performance saturation pulses. We propose to optimize adiabatic and pulse train saturation pulses for quantitative T1 mapping to have <1 % absolute residual longitudinal magnetization (|MZ/M0|) over ranges of B0 and [Formula: see text] (B1 scale factor) inhomogeneity found at 1.5 T and 3 T. Design parameters for an adiabatic BIR4-90 pulse were optimized for improved performance within 1.5 T B0 (±120 Hz) and [Formula: see text] (0.7-1.0) ranges. Flip angles in hard pulse trains of 3-6 pulses were optimized for 1.5 T and 3 T, with consideration of T1 values, field inhomogeneities (B0 = ±240 Hz and [Formula: see text]=0.4-1.2 at 3 T), and maximum achievable B1 field strength. Residual MZ/M0 was simulated and measured experimentally for current standard and optimized saturation pulses in phantoms and in-vivo human studies. T1 maps were acquired at 3 T in human subjects and a swine using a SAturation recovery single-SHot Acquisition (SASHA) technique with a standard 90°-90°-90° and an optimized 6-pulse train. Measured residual MZ/M0 in phantoms had excellent agreement with simulations over a wide range of B0 and [Formula: see text]. The optimized BIR4-90 reduced the maximum residual |MZ/M0| to <1 %, a 5.8× reduction compared to a reference BIR4-90. An optimized 3-pulse train achieved a maximum residual |MZ/M0| <1 % for the 1.5 T optimization range compared to 11.3 % for a standard 90°-90°-90° pulse train, while a 6-pulse train met this target for the wider 3 T ranges of B0 and [Formula: see text]. The 6-pulse train demonstrated more uniform saturation across both the myocardium and entire field of view than other saturation pulses in human studies. T1 maps were more spatially homogeneous with 6-pulse train SASHA than the reference 90°-90°-90° SASHA in both

  20. Dynamic structures of intact chicken erythrocyte chromatins as studied by 1H-31P cross-polarization NMR.

    PubMed Central

    Akutsu, H; Nishimoto, S; Kyogoku, Y

    1994-01-01

    The dynamic properties of DNA in intact chicken erythrocyte cells, nuclei, nondigested chromatins, digested soluble chromatins, H1, H5-depleted soluble chromatins and nucleosome cores were investigated by means of single-pulse and 1H-31P cross-polarization NMR. The temperature dependence of the phosphorus chemical shift anisotropy was identical for the former three in the presence of 3 mM MgCl2, suggesting that the local higher order structure is identical for these chromatins. The intrinsic phosphorus chemical shift anisotropy of the nucleosome cores was -159 ppm. The chemical shift anisotropy of DNA in the chromatins can be further averaged by the motion of the linker DNA. The spin-lattice relaxation time in the rotating frame of the proton spins (T1p) of the nondigested chromatins was measured at various locking fields. The result was analyzed on the assumption of the isotropic motion to get a rough value of the correlation time of the motion efficient for the relaxation, which was eventually ascribed to the segmental motion of the linker DNA with restricted amplitude. The 30 nm filament structure induced by NaCl was shown to be dynamically different from that induced by MgCl2. Side-by-side compaction of 30-nm filaments was suggested to be induced in the MgCl2 concentration range higher than 0.3 mM. Biological significance of the dynamic structure was discussed in connection with the results obtained. PMID:7948693

  1. In Vivo 1H NMR Spectroscopy of the Human Brain at 9.4 Tesla: Initial Results

    PubMed Central

    Deelchand, Dinesh Kumar; Van de Moortele, Pierre-François; Adriany, Gregor; Iltis, Isabelle; Andersen, Peter; Strupp, John P.; Vaughan, J. Thomas; Uğurbil, Kâmil; Henry, Pierre-Gilles

    2010-01-01

    In vivo proton NMR spectroscopy allows non-invasive detection and quantification of a wide range of biochemical compounds in the brain. Higher field strength is generally considered advantageous for spectroscopy due to increased signal-to-noise and increased spectral dispersion. So far 1H NMR spectra have been reported in the human brain up to 7 Tesla. In this study we show that excellent quality short echo time STEAM and LASER 1H NMR spectra can be measured in the human brain at 9.4 Tesla. The information content of the human brain spectra appears very similar to that measured in the past decade in rodent brains at the same field strength, in spite of broader linewidth in human brain. Compared to lower fields, the T1 relaxation times of metabolites were slightly longer while T2 relaxation values of metabolites were shorter (< 100 ms) at 9.4 Tesla. The linewidth of the total creatine (tCr) resonance at 3.03 ppm increased linearly with magnetic field (1.35 Hz/Tesla from 1.5 T to 9.4 T), with a minimum achievable tCr linewidth of around 12.5 Hz at 9.4 Tesla. At very high-field, B0 microsusceptibility effects are the main contributor to the minimum achievable linewidth. PMID:20598925

  2. In vivo1H NMR spectroscopy of the human brain at 9.4 T: Initial results

    NASA Astrophysics Data System (ADS)

    Deelchand, Dinesh Kumar; Moortele, Pierre-François Van de; Adriany, Gregor; Iltis, Isabelle; Andersen, Peter; Strupp, John P.; Thomas Vaughan, J.; Uğurbil, Kâmil; Henry, Pierre-Gilles

    2010-09-01

    In vivo proton NMR spectroscopy allows non-invasive detection and quantification of a wide range of biochemical compounds in the brain. Higher field strength is generally considered advantageous for spectroscopy due to increased signal-to-noise and increased spectral dispersion. So far 1H NMR spectra have been reported in the human brain up to 7 T. In this study we show that excellent quality short echo time STEAM and LASER 1H NMR spectra can be measured in the human brain at 9.4 T. The information content of the human brain spectra appears very similar to that measured in the past decade in rodent brains at the same field strength, in spite of broader linewidth in human brain. Compared to lower fields, the T1 relaxation times of metabolites were slightly longer while T2 relaxation values of metabolites were shorter (<100 ms) at 9.4 T. The linewidth of the total creatine (tCr) resonance at 3.03 ppm increased linearly with magnetic field (1.35 Hz/T from 1.5 T to 9.4 T), with a minimum achievable tCr linewidth of around 12.5 Hz at 9.4 T. At very high field, B0 microsusceptibility effects are the main contributor to the minimum achievable linewidth.

  3. T1 of 129Xe in Blood and the Role of Oxygenation

    NASA Astrophysics Data System (ADS)

    Albert, Mitchell S.; Kacher, Daniel F.; Balamore, Dilip; Venkatesh, Arvind K.; Jolesz, Ferenc A.

    1999-09-01

    In previous experiments by the authors, in which hyperpolarized 129Xe was dissolved in fresh blood samples, the T1 was found to be strongly dependent on the oxygenation level, the values increasing with oxygenation: T1 was about 4 s in deoxygenated samples and about 13 s in oxygenated samples. C. H. Tseng et al. (1997, J. Magn. Reson. 126, 79-86), on the other hand, recently reported extremely long T1 values using hyperpolarized 129Xe to create a "blood foam" and found that oxygenation decreased T1. In their experiments, the continual and rapid exchange of hyperpolarized 129Xe between the gas phase (within blood-foam bubbles) and the dissolved phase (in the skin of the bubbles) necessitated a complicated analysis to extract the effective blood T1. In the present study, the complications of hyperpolarized 129Xe exchange dynamics have been avoided by using thermally polarized 129Xe dissolved in whole blood and in suspensions of lysed red blood cells (RBC). During T1 measurements in whole blood, the samples were gently and continuously agitated, for the entire course of the experiment, to avert sedimentation. Oxygenation was found to markedly increase the T1 of 129Xe in blood, as originally measured, and it shifts the RBC resonance to a higher frequency. Carbon monoxide has a similar but somewhat stronger effect.

  4. Detection of Maltodextrin and Its Discrimination from Sucrose are Independent of the T1R2+T1R3 Heterodimer.

    PubMed

    Smith, Kimberly R; Spector, Alan Craig

    2017-08-02

    Maltodextrins, such as Maltrin and Polycose, are glucose polymer mixtures of varying chain lengths that are palatable to rodents. Although glucose and other sugars activate the T1R2+T1R3 "sweet" taste receptor, recent evidence from T1R2 or T1R3 knockout (KO) mice suggests that maltodextrins, despite their glucose polymer composition, activate a separate receptor mechanism to generate a taste percept qualitatively distinguishable from that of sweeteners. However, explicit discrimination of maltodextrins from prototypical sweeteners has not yet been psychophysically tested in any murine model. Therefore, mice lacking T1R2+T1R3 and wild-type controls were tested in a two-response taste discrimination task to determine if maltodextrins are 1) detectable when both receptor subunits are absent, and 2) perceptually distinct from that of sucrose irrespective of viscosity, intensity, and hedonics. Most KO mice displayed similar Polycose sensitivity as controls. However, some KO mice were only sensitive to the higher Polycose concentrations, implicating potential allelic variation in the putative polysaccharide receptor or downstream pathways unmasked by the absence of T1R2+T1R3. Varied Maltrin and sucrose concentrations of approximately matched viscosities were then presented to render the oral somatosensory features, intensity, and hedonic value of the solutions irrelevant. While both genotypes competently discriminated Maltrin from sucrose, performance was apparently driven by the different orosensory percepts of the two stimuli in control mice and the presence of a Maltrin but not sucrose orosensory cue in KO mice. These data support the proposed presence of an orosensory receptor mechanism that gives rise to a qualitatively distinguishable sensation from that of sucrose. Copyright © 2017, American Journal of Physiology-Regulatory, Integrative and Comparative Physiology.

  5. Myocardial T1 and T2 Mapping: Techniques and Clinical Applications

    PubMed Central

    Kim, Pan Ki; Im, Dong Jin; Suh, Young Joo; Park, Chul Hwan; Kim, Jin Young; Chang, Suyon; Lee, Hye-Jeong; Hur, Jin; Kim, Young Jin; Choi, Byoung Wook

    2017-01-01

    Cardiac magnetic resonance (CMR) imaging is widely used in various medical fields related to cardiovascular diseases. Rapid technological innovations in magnetic resonance imaging in recent times have resulted in the development of new techniques for CMR imaging. T1 and T2 image mapping sequences enable the direct quantification of T1, T2, and extracellular volume fraction (ECV) values of the myocardium, leading to the progressive integration of these sequences into routine CMR settings. Currently, T1, T2, and ECV values are being recognized as not only robust biomarkers for diagnosis of cardiomyopathies, but also predictive factors for treatment monitoring and prognosis. In this study, we have reviewed various T1 and T2 mapping sequence techniques and their clinical applications. PMID:28096723

  6. The 1H NMR Profile of Healthy Dog Cerebrospinal Fluid

    PubMed Central

    Musteata, Mihai; Nicolescu, Alina; Solcan, Gheorghe; Deleanu, Calin

    2013-01-01

    The availability of data for reference values in cerebrospinal fluid for healthy humans is limited due to obvious practical and ethical issues. The variability of reported values for metabolites in human cerebrospinal fluid is quite large. Dogs present great similarities with humans, including in cases of central nervous system pathologies. The paper presents the first study on healthy dog cerebrospinal fluid metabolomic profile using 1H NMR spectroscopy. A number of 13 metabolites have been identified and quantified from cerebrospinal fluid collected from a group of 10 mix breed healthy dogs. The biological variability as resulting from the relative standard deviation of the physiological concentrations of the identified metabolites had a mean of 18.20% (range between 9.3% and 44.8%). The reported concentrations for metabolites may be used as normal reference values. The homogeneity of the obtained results and the low biologic variability show that the 1H NMR analysis of the dog’s cerebrospinal fluid is reliable in designing and interpreting clinical and therapeutic trials in dogs with central nervous system pathologies. PMID:24376499

  7. MR T1ρ and T2 of Meniscus after Acute Anterior Cruciate Ligament Injuries

    PubMed Central

    Wang, Amy; Pedoia, Valentina; Su, Favian; Abramson, Elijah; Kretzschmar, Martin; Nardo, Lorenzo; Link, Thomas M.; McCulloch, Charles E.; Jin, Chengshi; Ma, C. Benjamin; Li, Xiaojuan

    2016-01-01

    Objective To evaluate differences in meniscal T1ρ and T2 quantification in patients with acute anterior cruciate ligament (ACL) injuries and to determine correlations of these differences with MR morphological grading and patient-reported outcomes. Design Bilateral knees of 52 patients with acute ACL injury and 20 healthy controls were scanned using 3T MRI T1ρ and T2 mapping in this prospective study. Quantitative analysis of the meniscus was performed in anterior and posterior horns of the lateral and medial menisci. Morphological meniscal damage was assessed using modified whole-organ MRI scores (WORMS). Measurements were compared between injured, uninjured contralateral, and control knees using a mixed-effects regression model. Correlations between meniscal T1ρ/T2, WORMS and Knee Injury and Osteoarthritis Outcome Scores (KOOS) were examined using partial correlation analysis. Results Mean meniscal T1ρ and T2 values were significantly higher in ACL-injured knees compared to control and contralateral knees. Menisci of ACL-injured knees without tears, including those limited to modified meniscal WORMS grade 0, also had significantly higher T1ρ and T2 values compared to menisci of uninjured knees. Within ACL-injured knees, T1ρ and T2 values showed significant positive associations with meniscal WORMS and significant negative associations with KOOS. Conclusion Acute ACL injuries are associated with significantly increased meniscal T1ρ and T2 values in both patients with and without meniscal lesions or tears, suggesting quantitative MRI provides more sensitive measures of meniscal differences compared to traditional morphological MRI sequences. Correlation between meniscal T1ρ/T2 and KOOS suggest that quantitative MRI is reflective of the extent of patients’ clinical symptoms. PMID:26620091

  8. Comparison of T1rho and T2 Mapping of Knee Articular Cartilage in an Asymptomatic Population

    PubMed Central

    Yoon, Min A; Im, A Lan; Kang, Chang Ho; Kim, Baek Hyun; Kim, In Seong

    2016-01-01

    Objective To analyze subregional differences in T1rho (T1ρ) and T2 values and their correlation in asymptomatic knee cartilage, and to evaluate angular dependence with magic angles. Materials and Methods Six asymptomatic volunteers underwent knee MRI with T1ρ and T2 mapping. T1ρ and T2 values were measured by two radiologists independently, at nine subregions in the medial femoral condyle (MFC) cartilage, at angles of ± 0°, 15°, 35°, 55°, 75° respective to a vertical line (B0) bisecting the width of the distal femur, and at two locations in the patella. Subregional values of T1ρ and T2 were analyzed and significant differences in three divided portions of the MFC (anterior, central, and posterior) were statistically evaluated. Correlation between T1ρ and T2 and angular dependence with magic angles were also assessed for statistical significance. Results T1ρ values were lowest at +15° and highest at -55°. T2 values were lowest at +75° and highest at +35°. Both T1ρ and T2 were higher in superior patella than inferior patella. T1ρ showed significant differences in the three divided portions of the MFC, while T2 showed significant differences only between central and posterior portions. There was a weak correlation between T1ρ and T2 (r = 0.217, p = 0.127). T1ρ showed more angular dependence than T2. Conclusion T1ρ and T2 showed different subregional values and angular dependence in asymptomatic knee cartilage with a weak correlation. Awareness of these differences will aid in assessment of cartilage in a specific subregion of the knee. PMID:27833407

  9. A simple method for NMR t1 noise suppression

    NASA Astrophysics Data System (ADS)

    Mo, Huaping; Harwood, John S.; Yang, Danzhou; Post, Carol Beth

    2017-03-01

    t1 noise appears as random or semi-random spurious streaks along the indirect t1 (F1) dimension of a 2D or nD NMR spectrum. It can significantly downgrade spectral quality, especially for spectra with strong diagonal signals such as NOESY, because useful and weak cross-peaks can be easily buried under t1 noise. One of the significant contributing factors to t1 noise is unwanted and semi-random F2 signal modulation during t1 acquisition. As such, t1 noise from different acquisitions is unlikely to correlate with each other strongly. In the case of NOESY, co-addition of multiple spectra significantly reduces t1 noise compared with conventional acquisition with the same amount of total acquisition time and resolution.

  10. Cardiac Fibrosis in Aortic Stenosis and Hypertensive Heart Disease Assessed by Magnetic Resonance T1 Mapping.

    PubMed

    von Knobelsdorff-Brenkenhoff, Florian; Mueller, Anna-Katharina; Prothmann, Marcel; Hennig, Pierre; Dieringer, Matthias A; Schmacht, Luisa; Greiser, Andreas; Schulz-Menger, Jeanette

    2016-09-01

    Continuous pressure overload may lead to subclinical myocardial tissue changes in patients with hypertensive heart disease (HHD) and aortic stenosis (AS). The study aim was to detect interstitial fibrosis using quantitative cardiovascular magnetic resonance. Fifteen patients with HHD (arterial hypertension + septal wall thickness ≥13 mm), 33 with AS (eight mild, 15 moderate, 10 severe), and 60 healthy controls were enrolled. Native T1 maps (modified Look-Locker inversion recovery) were obtained in a basal, mid-ventricular, and apical shortaxis slice of the left ventricle to assess cardiac fibrosis. Focal fibrosis was assessed with late gadolinium enhancement (LGE). Patients with HHD and controls did not differ regarding the native myocardial T1 values, both per slice and per segment. In AS patients, apical native T1 values were lower than in controls, and there was a trend towards higher T1 values in the septum in severe AS (1172.6 ± 62.0 ms versus 1152.9 ± 43.9 ms). Five HHD patients and 11 AS patients had non-ischemic fibrosis in LGE images. Native T1 times did not differ between LGE-positive and LGEnegative groups (both with inclusion and exclusion of segments with LGE). T1 mapping did not reveal any evidence of abnormal interstitial fibrosis in HHD subjects with mild hypertrophy. In severe AS, a trend towards more interstitial fibrosis was present, but absolute differences were small for decision making.

  11. Is the T1ρ MRI profile of hyaline cartilage in the normal hip uniform?

    PubMed

    Rakhra, Kawan S; Cárdenas-Blanco, Arturo; Melkus, Gerd; Schweitzer, Mark E; Cameron, Ian G; Beaulé, Paul E

    2015-04-01

    T1ρ MRI is an imaging technique sensitive to proteoglycan (PG) content of hyaline cartilage. However, normative T1ρ values have not been established for the weightbearing cartilage of the hip, and it is not known whether it is uniform or whether there is topographic variation. Knowledge of the T1ρ profile of hyaline cartilage in the normal hip is important for establishing a baseline against which comparisons can be made to experimental and clinical arthritic subjects. In this diagnostic study, we determined (1) the T1ρ MRI values of hyaline cartilage of the normal hip; and (2) whether the T1ρ MRI profile of the normal hip hyaline cartilage is uniform. Fourteen asymptomatic volunteers (11 men, three women; mean age, 35 years) prospectively underwent 1.5-T T1ρ MRI of a single hip. The weightbearing hyaline cartilage bilayer of the acetabulum and femoral head was evaluated on sagittal images and segmented into four zones: (1) anterior; (2) anterosuperior; (3) posterosuperior; and (4) and posterior. For the full region of interest and within each zone and each sagittal slice, we calculated the mean T1ρ relaxation value, a parameter that indirectly quantifies PG content, where T1ρ is inversely related to PG concentration. There was variation in the T1ρ relaxation values depending on zone (anterior to posterior) and slice (medial to lateral). When combining the most anterior quadrants (Zones 1 and 2), the T1ρ relaxation values were lower than those in the combined posterior quadrants (Zones 3 and 4) (30.4 msec versus 32.2 msec, respectively; p = 0.002), reflecting higher PG concentration. There was a difference between the T1ρ relaxation values of the sagittal slices (p = 0.038), most pronounced anteriorly in Zone 1 (26.6 msec, p = 0.001). With a selective combination of zones and slices, there were lower mean T1ρ values in the anterolateral-most region compared with the remainder of the weightbearing portion of the hip (28.6 msec versus 32.2 msec

  12. Impact of denoising on precision and accuracy of saturation-recovery-based myocardial T1 mapping.

    PubMed

    Bustin, Aurélien; Ferry, Pauline; Codreanu, Andrei; Beaumont, Marine; Liu, Shufang; Burschka, Darius; Felblinger, Jacques; Brau, Anja C S; Menini, Anne; Odille, Freddy

    2017-04-04

    To evaluate the impact of a novel postprocessing denoising technique on accuracy and precision in myocardial T1 mapping. This study introduces a fast and robust denoising method developed for magnetic resonance T1 mapping. The technique imposes edge-preserving regularity and exploits the co-occurence of spatial gradients in the acquired T1 -weighted images. The proposed approach was assessed in simulations, ex vivo data and in vivo imaging on a cohort of 16 healthy volunteers (12 males, average age 39 ± 8 years, 62 ± 9 bpm) both in pre- and postcontrast injection. The method was evaluated in myocardial T1 mapping at 3T with a saturation-recovery technique that is accurate but sensitive to noise. ROIs in the myocardium and left-ventricle blood pool were analyzed by an experienced reader. Mean T1 values and standard deviation were extracted and compared in all studies. Simulations on synthetic phantom showed signal-to-noise ratio and sharpness improvement with the proposed method in comparison with conventional denoising. In vivo results demonstrated that our method preserves accuracy, as no difference in mean T1 values was observed in the myocardium (precontrast: 1433/1426 msec, 95%CI: [-40.7, 55.9], p = 0.75, postcontrast: 766/759 msec, 95%CI: [-60.7, 77.2], p = 0.8). Meanwhile, precision was improved with standard deviations of T1 values being significantly decreased (precontrast: 223/151 msec, 95%CI: [27.3, 116.5], p = 0.003, postcontrast: 176/135 msec, 95%CI: [5.5, 77.1], p = 0.03). The proposed denoising method preserves accuracy and improves precision in myocardial T1 mapping, with the potential to offer better map visualization and analysis. 3 J. Magn. Reson. Imaging 2017. © 2017 International Society for Magnetic Resonance in Medicine.

  13. Brain abnormalities in bipolar disorder detected by quantitative T1ρ mapping.

    PubMed

    Johnson, C P; Follmer, R L; Oguz, I; Warren, L A; Christensen, G E; Fiedorowicz, J G; Magnotta, V A; Wemmie, J A

    2015-02-01

    Abnormal metabolism has been reported in bipolar disorder, however, these studies have been limited to specific regions of the brain. To investigate whole-brain changes potentially associated with these processes, we applied a magnetic resonance imaging technique novel to psychiatric research, quantitative mapping of T1 relaxation in the rotating frame (T1ρ). This method is sensitive to proton chemical exchange, which is affected by pH, metabolite concentrations and cellular density with high spatial resolution relative to alternative techniques such as magnetic resonance spectroscopy and positron emission tomography. Study participants included 15 patients with bipolar I disorder in the euthymic state and 25 normal controls balanced for age and gender. T1ρ maps were generated and compared between the bipolar and control groups using voxel-wise and regional analyses. T1ρ values were found to be elevated in the cerebral white matter and cerebellum in the bipolar group. However, volumes of these areas were normal as measured by high-resolution T1- and T2-weighted magnetic resonance imaging. Interestingly, the cerebellar T1ρ abnormalities were normalized in participants receiving lithium treatment. These findings are consistent with metabolic or microstructural abnormalities in bipolar disorder and draw attention to roles of the cerebral white matter and cerebellum. This study highlights the potential utility of high-resolution T1ρ mapping in psychiatric research.

  14. Contrast Enhancement by Combining T1- and T2-weighted Structural Brain MR Images

    PubMed Central

    Misaki, Masaya; Savitz, Jonathan; Zotev, Vadim; Phillips, Raquel; Yuan, Han; Young, Kymberly D.; Drevets, Wayne C.; Bodurka, Jerzy

    2014-01-01

    Purpose In order to more precisely differentiate cerebral structures in neuroimaging studies, a novel technique for enhancing the tissue contrast based on a combination of T1-weighetd (T1w) and T2-weighed (T2w) magnetic resonance imaging (MRI) images was developed. Methods The combined image (CI) was calculated as CI = (T1w−sT2w)/(T1w+sT2w), where sT2w is the scaled T2-weighted image. The scaling factor was calculated to adjust the gray matter voxel intensities in the T2w image so that their median value equaled that of the gray matter voxel intensities in the T1w image. The image intensity homogeneity within a tissue and the discriminability between tissues in the CI versus the separate T1w and T2w images were evaluated using the segmentation by FSL and FreeSurfer software. Results The combined image significantly improved homogeneity in the white and gray matter compared to the T1w images alone. The discriminability between white and gray matter also improved significantly by applying the CI approach. Significant enhancements to the homogeneity and discriminability also were achieved in most subcortical nuclei tested, with the exception of the amygdala and the thalamus. Conclusion The tissue discriminability enhancement offered by the CI potentially enables more accurate neuromorphometric analyses of brain structures. PMID:25533337

  15. L-Theanine elicits umami taste via the T1R1 + T1R3 umami taste receptor.

    PubMed

    Narukawa, Masataka; Toda, Yasuka; Nakagita, Tomoya; Hayashi, Yukako; Misaka, Takumi

    2014-06-01

    L-Theanine is a unique amino acid present in green tea. It elicits umami taste and has a considerable effect on tea taste and quality. We investigated L-theanine activity on the T1R1 + T1R3 umami taste receptor. L-Theanine activated T1R1 + T1R3-expressing cells and showed a synergistic response with inosine 5'-monophosphate. The site-directed mutagenesis analysis revealed that L-theanine binds to L-amino acid binding site in the Venus flytrap domain of T1R1. This study shows that L-theanine elicits an umami taste via T1R1 + T1R3.

  16. A Unified Maximum Likelihood Framework for Simultaneous Motion and $T_{1}$ Estimation in Quantitative MR $T_{1}$ Mapping.

    PubMed

    Ramos-Llorden, Gabriel; den Dekker, Arnold J; Van Steenkiste, Gwendolyn; Jeurissen, Ben; Vanhevel, Floris; Van Audekerke, Johan; Verhoye, Marleen; Sijbers, Jan

    2017-02-01

    In quantitative MR T1 mapping, the spin-lattice relaxation time T1 of tissues is estimated from a series of T1 -weighted images. As the T1 estimation is a voxel-wise estimation procedure, correct spatial alignment of the T1 -weighted images is crucial. Conventionally, the T1 -weighted images are first registered based on a general-purpose registration metric, after which the T1 map is estimated. However, as demonstrated in this paper, such a two-step approach leads to a bias in the final T1 map. In our work, instead of considering motion correction as a preprocessing step, we recover the motion-free T1 map using a unified estimation approach. In particular, we propose a unified framework where the motion parameters and the T1 map are simultaneously estimated with a Maximum Likelihood (ML) estimator. With our framework, the relaxation model, the motion model as well as the data statistics are jointly incorporated to provide substantially more accurate motion and T1 parameter estimates. Experiments with realistic Monte Carlo simulations show that the proposed unified ML framework outperforms the conventional two-step approach as well as state-of-the-art model-based approaches, in terms of both motion and T1 map accuracy and mean-square error. Furthermore, the proposed method was additionally validated in a controlled experiment with real T1 -weighted data and with two in vivo human brain T1 -weighted data sets, showing its applicability in real-life scenarios.

  17. Longitudinal changes of cortical microstructure in Parkinson's disease assessed with T1 relaxometry.

    PubMed

    Nürnberger, Lucas; Gracien, René-Maxime; Hok, Pavel; Hof, Stephanie-Michelle; Rüb, Udo; Steinmetz, Helmuth; Hilker, Rüdiger; Klein, Johannes C; Deichmann, Ralf; Baudrexel, Simon

    2017-01-01

    Histological evidence suggests that pathology in Parkinson's disease (PD) goes beyond nigrostriatal degeneration and also affects the cerebral cortex. Quantitative MRI (qMRI) techniques allow the assessment of changes in brain tissue composition. However, the development and pattern of disease-related cortical changes have not yet been demonstrated in PD with qMRI methods. The aim of this study was to investigate longitudinal cortical microstructural changes in PD with quantitative T1 relaxometry. 13 patients with mild to moderate PD and 20 matched healthy subjects underwent high resolution T1 mapping at two time points with an interval of 6.4 years (healthy subjects: 6.5 years). Data from two healthy subjects had to be excluded due to MRI artifacts. Surface-based analysis of cortical T1 values was performed with the FreeSurfer toolbox. In PD patients, a widespread decrease of cortical T1 was detected during follow-up which affected large parts of the temporo-parietal and occipital cortices and also frontal areas. In contrast, age-related T1 decrease in the healthy control group was much less pronounced and only found in lateral frontal, parietal and temporal areas. Average cortical T1 values did not differ between the groups at baseline (p = 0.17), but were reduced in patients at follow-up (p = 0.0004). Annualized relative changes of cortical T1 were higher in patients vs. healthy subjects (patients: - 0.72 ± 0.64%/year; healthy subjects: - 0.17 ± 0.41%/year, p = 0.007). In patients with PD, the development of widespread changes in cortical microstructure was observed as reflected by a reduction of cortical T1. The pattern of T1 decrease in PD patients exceeded the normal T1 decrease as found in physiological aging and showed considerable overlap with the pattern of cortical thinning demonstrated in previous PD studies. Therefore, cortical T1 might be a promising additional imaging marker for future longitudinal PD studies. The biological

  18. Fast and simultaneous determination of (1) H-(1) H and (1) H-(19) F scalar couplings in complex spin systems: Application of PSYCHE homonuclear broadband decoupling.

    PubMed

    Kakita, Veera Mohana Rao; Rachineni, Kavitha; Hosur, Ramakrishna V

    2017-07-21

    The present manuscript focuses on fast and simultaneous determination of (1) H-(1) H and (1) H-(19) F scalar couplings in fluorinated complex steroid molecules. Incorporation of broadband PSYCHE homonuclear decoupling in the indirect dimension of zero-quantum filtered diagonal experiments (F1-PSYCHE-DIAG) suppresses (1) H-(1) H scalar couplings; however, it retains (1) H-(19) F scalar couplings (along F1 dimension) for the (19) F coupled protons while preserving the pure-shift nature for (1) H resonances uncoupled to (19) F. In such cases, along the direct dimensions, (1) H-(1) H scalar coupling multiplets deconvolute and they appear as duplicated multiplets for the (19) F coupled protons, which facilitates unambiguous discrimination of (19) F coupled (1) H chemical sites from the others. Further, as an added advantage, data acquisition has been accelerated by invoking the known ideas of spectral aliasing in the F1-PSYCHE-DIAG scheme and experiments demand only ~10 min of spectrometer times. Copyright © 2017 John Wiley & Sons, Ltd.

  19. Further exploration of MRI techniques for liver T1rho quantification.

    PubMed

    Zhao, Feng; Yuan, Jing; Deng, Min; Lu, Pu-Xuan; Ahuja, Anil T; Wang, Yi-Xiang J

    2013-12-01

    With biliary duct ligation and CCl4 induced rat liver fibrosis models, recent studies showed that MR T1rho imaging is able to detect liver fibrosis, and the degree of fibrosis is correlated with the degree of elevation of the T1rho measurements, suggesting liver T1rho quantification may play an important role for liver fibrosis early detection and grading. It has also been reported it is feasible to obtain consistent liver T1rho measurement for human subjects at 3 Tesla (3 T), and preliminary clinical data suggest liver T1rho is increased in patients with cirrhosis. In these previous studies, T1rho imaging was used with the rotary-echo spin-lock pulse for T1rho preparation, and number of signal averaging (NSA) was 2. Due to the presence of inhomogeneous B0 field, artifacts may occur in the acquired T1rho-weighted images. The method described by Dixon et al. (Magn Reson Med 1996;36:90-4), which is a hard RF pulse with 135° flip angle and same RF phase as the spin-locking RF pulse is inserted right before and after the spin-locking RF pulse, has been proposed to reduce sensitivity to B0 field inhomogeneity in T1rho imaging. In this study, we compared the images scanned by rotary-echo spin-lock pulse method (sequence 1) and the pulse modified according to Dixon method (sequence 2). When the artifacts occurred in T1rho images, we repeated the same scan until satisfactory. We accepted images if artifact in liver was less than 10% of liver area by visual estimation. When NSA =2, the breath-holding duration for data acquisition of one slice scanning was 8 sec due to a delay time of 6,000 ms for magnetization restoration. If NSA =1, the duration was shortened to be 2 sec. In previous studies, manual region of interest (ROI) analysis of T1rho map was used. In this current study, histogram analysis was also applied to evaluate liver T1rho value on T1rho maps. MRI data acquisition was performed on a 3 T clinical scanner. There were 29 subjects with 61 examinations obtained

  20. T1-201 chloride scintigraphy for bone tumors and soft part sarcomas

    SciTech Connect

    Terui, S.; Oyamada, H.; Nishikawa, K.; Beppu, Y.; Fukuma, H.

    1984-01-01

    The author investigated T1-201 chloride as a tumor scanning agent of both tumors and soft part sarcomas. Six bone tumors (2 with Ewing sarcoma, 3 with osteosarcoma and 1 with giant cell tumor) and 3 soft part sarcoma (1 with liposarcoma and 2 with malignant fibrous histiocytoma (MFH)) were examined. All but one MFH were untreated primary cases. The diagnosis was determined from biopsy specimen. One patient with Ewing sarcoma had bone metastases. All cases were subsequently received chemotherpeutic agents. Surgery or local irradiation were also used in treatment. T1-201 scintigraphy were performed with intravenous administration of 2 mCi of T1-201 chloride before initiation of therapy. In addition, follow-up examinations were done in 4 patients (2 with Ewing sarcoma and 2 with osteosarcoma) to study the effect of chemotherapy on T1-201 uptake by the tumor. Tc-99m bone scans were available for comparison in 6 tumor. Ga-67 citrate scans were also examined for the 3 soft part sarcomas. The untreated tumors even in the metastatic lesions of Ewing sarcoma were distinctly visualized with T1-201 in all cases. The distribution of T1-201 in the tumors was sometimes different from that of Tc-99m and similar to that of Ga-67. Of 3 out of the 4 follow-up patients, the post-therapy scan showed reduction in T1-201 uptake more markedly than Tc-99m uptake during effective chemotherapy. The other one patient had not responded to the treatment so that the scan showed no changes in T1-201 uptake. These findings indicate that the tumor imaging with T1-201 is useful in the diagnosis of these malignant tumors and may be of value in assessing the response of bone tumors to chemotherapy.

  1. Human genetic polymorphisms in T1R1 and T1R3 taste receptor subunits affect their function.

    PubMed

    Raliou, Mariam; Grauso, Marta; Hoffmann, Brice; Schlegel-Le-Poupon, Claire; Nespoulous, Claude; Débat, Hélène; Belloir, Christine; Wiencis, Anna; Sigoillot, Maud; Bano, Singh Preet; Trotier, Didier; Pernollet, Jean-Claude; Montmayeur, Jean-Pierre; Faurion, Annick; Briand, Loïc

    2011-07-01

    Umami is the typical taste induced by monosodium glutamate (MSG), which is thought to be detected by the heterodimeric G protein-coupled receptor, T1R1 and T1R3. Previously, we showed that MSG detection thresholds differ substantially between individuals and we further showed that nontaster and hypotaster subjects are associated with nonsynonymous single polymorphisms occurring in the T1R1 and T1R3 genes. Here, we show using functional expression that both amino acid substitutions (A110V and R507Q) in the N-terminal ligand-binding domain of T1R1 and the 2 other ones (F749S and R757C), located in the transmembrane domain of T1R3, severely impair in vitro T1R1/T1R3 response to MSG. A molecular model of the ligand-binding region of T1R1/T1R3 provides a mechanistic explanation supporting functional expression data. The data presented here support causal relations between the genotype and previous in vivo psychophysical studies in human evaluating sensitivity to MSG. © The Author 2011. Published by Oxford University Press. All rights reserved.

  2. PANDA-T1ρ: Integrating principal component analysis and dictionary learning for fast T1ρ mapping.

    PubMed

    Zhu, Yanjie; Zhang, Qinwei; Liu, Qiegen; Wang, Yi-Xiang J; Liu, Xin; Zheng, Hairong; Liang, Dong; Yuan, Jing

    2015-01-01

    Long scanning time greatly hinders the widespread application of spin-lattice relaxation in rotating frame (T1ρ) in clinics. In this study, a novel method is proposed to reconstruct the T1ρ-weighted images from undersampled k-space data and hence accelerate the acquisition of T1ρ imaging. The proposed approach (PANDA-T1ρ) combined the benefit of PCA and dictionary learning when reconstructing image from undersampled data. Specifically, the PCA transform was first used to sparsify the image series along the parameter direction and then the sparsified images were reconstructed by means of dictionary learning and finally solved the images. A variation of PANDA-T1ρ was also developed for the heavy noise case. Numerical simulation and in vivo experiments were carried out with the accelerating factor from 2 to 4 to verify the performance of PANDA-T1ρ. The reconstructed T1ρ maps using the PANDA-T1ρ method were found to be comparable to the reference at all verified acceleration factors. Moreover, the variation exhibited better performance than the original version when the k-space data were contaminated by heavy noise. PANDA-T1ρ can significantly reduce the scanning time of T1ρ by integrating PCA and dictionary learning and provides better parameter estimation than the state-of-art methods for a fixed acceleration factor. © 2014 Wiley Periodicals, Inc.

  3. Relationship Between T1 Slope and Cervical Alignment Following Multilevel Posterior Cervical Fusion Surgery: Impact of T1 Slope Minus Cervical Lordosis.

    PubMed

    Hyun, Seung-Jae; Kim, Ki-Jeong; Jahng, Tae-Ahn; Kim, Hyun-Jib

    2016-04-01

    Retrospective study. To assess the relationship between sagittal alignment of the cervical spine and patient-reported health-related quality-of-life scores following multilevel posterior cervical fusion, and to explore whether an analogous relationship exists in the cervical spine using T1 slope minus C2-C7 lordosis (T1S-CL). A recent study demonstrated that, similar to the thoracolumbar spine, the severity of disability increases with sagittal malalignment following cervical reconstruction surgery. From 2007 to 2013, 38 consecutive patients underwent multilevel posterior cervical fusion for cervical stenosis, myelopathy, and deformities. Radiographic measurements included C0-C2 lordosis, C2-C7 lordosis, C2-C7 sagittal vertical axis (SVA), T1 slope, and T1S-CL. Pearson correlation coefficients were calculated between pairs of radiographic measures and health-related quality-of-life. C2-C7 SVA positively correlated with neck disability index (NDI) scores (r = 0.495). C2-C7 lordosis (P = 0.001) and T1S-CL (P = 0.002) changes correlated with NDI score changes after surgery. For significant correlations between C2-C7 SVA and NDI scores, regression models predicted a threshold C2-C7 SVA value of 50 mm, beyond which correlations were most significant. The T1S-CL also correlated positively with C2-C7 SVA and NDI scores (r = 0.871 and r = 0.470, respectively). Results of the regression analysis indicated that a C2-C7 SVA value of 50 mm corresponded to a T1S-CL value of 26.1°. This study showed that disability of the neck increased with cervical sagittal malalignment following surgical reconstruction and a greater T1S-CL mismatch was associated with a greater degree of cervical malalignment. Specifically, a mismatch greater than 26.1° corresponded to positive cervical sagittal malalignment, defined as C2-C7 SVA greater than 50 mm. 3.

  4. Crystalline 1H-1,2,3-triazol-5-ylidenes

    SciTech Connect

    Bertrand, Guy; Gulsado-Barrios, Gregorio; Bouffard, Jean; Donnadieu, Bruno

    2016-08-02

    The present invention provides novel and stable crystalline 1H-1,2,3 triazolium carbenes and metal complexes of 1H-1,2,3 triazolium carbenes. The present invention also provides methods of making 1H-1,2,3 triazolium carbenes and metal complexes of 1H-1,2,3 triazolium carbenes. The present invention also provides methods of using 1H-1,2,3 triazolium carbenes and metal complexes of 1H-1,2,3 triazolium carbenes in catalytic reactions.

  5. Comparative clinicopathological characteristics of colon and rectal T1 carcinoma

    PubMed Central

    Ichimasa, Katsuro; Kudo, Shin-Ei; Miyachi, Hideyuki; Kouyama, Yuta; Hayashi, Takemasa; Wakamura, Kunihiko; Hisayuki, Tomokazu; Kudo, Toyoki; Misawa, Masashi; Mori, Yuichi; Matsudaira, Shingo; Hidaka, Eiji; Hamatani, Shigeharu; Ishida, Fumio

    2017-01-01

    Lymph node metastasis significantly influences the management of patients with colorectal carcinoma. It has been observed that the biology of colorectal carcinoma differs by location. The aim of the current study was to retrospectively compare the clinicopathological characteristics of patients with colon and rectal T1 carcinomas, particularly their rates of lymph node metastasis. Of the 19,864 patients who underwent endoscopic or surgical resection of colorectal neoplasms at Showa University Northern Yokohama Hospital, 557 had T1 surgically resected carcinomas, including 457 patients with colon T1 carcinomas and 100 patients with rectal T1 carcinomas. Analysed clinicopathological features included patient age, gender, tumor size, morphology, tumor budding, invasion depth, vascular invasion, histological grade, lymphatic invasion and lymph node metastasis. Rectal T1 carcinomas were significantly larger than colon T1 carcinomas (mean ± standard deviation: 23.7±13.1 mm vs. 19.9±11.0 mm, P<0.01) and were accompanied by significantly higher rates of vascular invasion (48.0% vs. 30.2%, P<0.01). Significant differences were not observed among any other clinicopathological factors. In conclusion, tumor location itself was not a risk factor for lymph node metastasis in colorectal T1 carcinomas, even though on average, rectal T1 carcinomas were larger and accompanied by a significantly higher rate of vascular invasion than colon T1 carcinomas. PMID:28356962

  6. Two distinct determinants of ligand specificity in T1R1/T1R3 (the umami taste receptor).

    PubMed

    Toda, Yasuka; Nakagita, Tomoya; Hayakawa, Takashi; Okada, Shinji; Narukawa, Masataka; Imai, Hiroo; Ishimaru, Yoshiro; Misaka, Takumi

    2013-12-27

    Umami taste perception in mammals is mediated by a heteromeric complex of two G-protein-coupled receptors, T1R1 and T1R3. T1R1/T1R3 exhibits species-dependent differences in ligand specificity; human T1R1/T1R3 specifically responds to L-Glu, whereas mouse T1R1/T1R3 responds more strongly to other L-amino acids than to L-Glu. The mechanism underlying this species difference remains unknown. In this study we analyzed chimeric human-mouse receptors and point mutants of T1R1/T1R3 and identified 12 key residues that modulate amino acid recognition in the human- and mouse-type responses in the extracellular Venus flytrap domain of T1R1. Molecular modeling revealed that the residues critical for human-type acidic amino acid recognition were located at the orthosteric ligand binding site. In contrast, all of the key residues for the mouse-type broad response were located at regions outside of both the orthosteric ligand binding site and the allosteric binding site for inosine-5'-monophosphate (IMP), a known natural umami taste enhancer. Site-directed mutagenesis demonstrated that the newly identified key residues for the mouse-type responses modulated receptor activity in a manner distinct from that of the allosteric modulation via IMP. Analyses of multiple point mutants suggested that the combination of two distinct determinants, amino acid selectivity at the orthosteric site and receptor activity modulation at the non-orthosteric sites, may mediate the ligand specificity of T1R1/T1R3. This hypothesis was supported by the results of studies using nonhuman primate T1R1 receptors. A complex molecular mechanism involving changes in the properties of both the orthosteric and non-orthosteric sites of T1R1 underlies the determination of ligand specificity in mammalian T1R1/T1R3.

  7. Microarray gene expression profiling and analysis of bladder cancer supports the sub-classification of T1 tumours into T1a and T1b stages.

    PubMed

    Descotes, Françoise; Dessen, Philippe; Bringuier, Pierre Paul; Decaussin, Myriam; Martin, Pierre Marie; Adams, Marjorie; Villers, Arnauld; Lechevallier, Eric; Rebillard, Xavier; Rodriguez-Lafrasse, Claire; Devonec, Marian; Paparel, Philippe; Perrin, Paul; Lazar, Vladimir; Ruffion, Alain

    2014-02-01

    To try and identify a molecular signature for pathological staging and/or grading. through microarray analysis. We performed a prospective multicentre study between September 2007 and May 2008 that included 108 bladder tumours (45 pTa, 35 pT1 and 28>pT1). Microarray analysis was performed using Agilent Technologies Human Whole Genome 4 × 44K oligonucleotide microarrays (Agilent, Santa Clara, CA, USA). A 'dual colour' method was used vs a reference pool of tumours. From the lists of genes provided by the Biometric Research Branch class comparison analyses, we validated the microarray results of 38 selected differentially expressed genes using reverse transcriptase quantitative PCR in another bladder tumour cohort (n = 95). The cluster 'superficial vs invasive stage' correctly classified 92.9% of invasive stages and 66.3% of superficial stages. Among the superficial tumours, the cluster analysis showed that pT1b tumours were closer to invasive stages than pT1a tumours. We also found molecular differences between low and high grade superficial tumours, but these differences were less well defined than the difference observed for staging. We confirmed that the histopathological classification into subgroups pTa, pT1a and pT1b can be translated into a molecular signature with a continuous progression of deregulation (overexpression or repression of these genes) from superficial (pTa) to more invasive (pT1a then b) stages. © 2013 The Authors. BJU International © 2013 BJU International.

  8. [The correlation between T1 tilt and cosmetic shoulder balance in Lenke type 2 adolescent idiopathic scoliosis patients].

    PubMed

    Qiu, Xu-sheng; Qiu, Yong; Jiang, Jun; Wang, Bin; Zhu, Ze-zhang; Qian, Bang-ping; Yu, Yang

    2013-08-01

    To study the relationship between T1 tilt and cosmetic shoulder balance in adolescent idiopathic scoliosis (AIS) patients. Seventy-one Lenke type 2 AIS patients were recruited into the present study from January 2010 to December 2011. There were 61 female and 10 male patients, the average age was (15.1 ± 2.9) years (range 10-18 years); the average Risser sign was 2.8 (range 1-5). The patients were photographed from the back in neutral standing position on level ground wearing underpants. Also, all the patients had a standing posterior-anterior radiograph in a relaxed standing position. The cosmetic shoulder height (CSH), which included cosmetic inner shoulder height (CSHi) and cosmetic outer shoulder height (CSHo), were measured in the photographs. Positive value was defined as left shoulder was higher than the right shoulder, and negative value was defined as right shoulder was higher than the left shoulder. CSH > 5 mm was defined as positive CSH, CSH < -5 mm was defined as negative CSH, -5 mm ≤ CSH ≤ 5 mm was defined as leveled CSH. T1 tilts were measured in the posterior-anterior radiographs. Positive value was defined as the left proximal vertebral body up and right lower vertebral body down, and negative value was defined as the right proximal vertebral body up and left lower vertebral body down. T1 tilt > 5° was defined as positive T1 tilt, T1 tilt < -5° was defined as negative T1 tilt, -5° ≤ T1 tilt ≤ 5° was defined as leveled T1 tilt. T1 tilt was found to be significantly correlated with CSHi and CSHo (r = 0.25 and 0.28, P < 0.05).For positive T1 tilt patients, there were 59.0% (36/61) patients with positive CSHo, 37.7% (23/61)with leveled CSHo, and 3.3% (2/61)with negative CSHo.For the patients with leveled T1 tilt, it was 3/10, 5/10 and 2/10.For positive T1 tilt patients, there were 83.6% (51/61) patients with positive CSHi, 11.5% (7/61) with leveled CSHi, and 4.9% (3/61) with negative CSHi; For the patients with leveled T1 tilt, it was 6

  9. Myocardial T1 Mapping: Techniques and Potential Applications

    PubMed Central

    Burt, Jeremy R.; Zimmerman, Stefan L.; Kamel, Ihab R.; Halushka, Marc

    2014-01-01

    Myocardial fibrosis is a common endpoint in a variety of cardiac diseases and a major independent predictor of adverse cardiac outcomes. Short of histopathologic analysis, which is limited by sampling bias, most diagnostic modalities are limited in their depiction of myocardial fibrosis. Cardiac magnetic resonance (MR) imaging has the advantage of providing detailed soft-tissue characterization, and a variety of novel quantification methods have further improved its usefulness. Contrast material–enhanced cardiac MR imaging depends on differences in signal intensity between regions of scarring and adjacent normal myocardium. Diffuse myocardial fibrosis lacks these differences in signal intensity. Measurement of myocardial T1 times (T1 mapping) with gadolinium-enhanced inversion recovery–prepared sequences may depict diffuse myocardial fibrosis and has good correlation with ex vivo fibrosis content. T1 mapping calculates myocardial T1 relaxation times with image-based signal intensities and may be performed with standard cardiac MR imagers and radiologic workstations. Myocardium with diffuse fibrosis has greater retention of contrast material, resulting in T1 times that are shorter than those in normal myocardium. Early studies have suggested that diffuse myocardial fibrosis may be distinguished from normal myocardium with T1 mapping. Large multicenter studies are needed to define the role of T1 mapping in developing prognoses and therapeutic assessments. However, given its strengths as a noninvasive method for direct quantification of myocardial fibrosis, T1 mapping may eventually play an important role in the management of cardiac disease. © RSNA, 2014 PMID:24617686

  10. Measurement of intervertebral disc pressure with T 1ρ MRI.

    PubMed

    Wang, Chenyang; Witschey, Walter; Elliott, Mark A; Borthakur, Arijitt; Reddy, Ravinder

    2010-12-01

    The aim of this study is to demonstrate T(1ρ) MRI's capability for measuring intervertebral disc osmotic pressure. Self-coregistered sodium and T(1ρ) -weighted MR images were acquired on ex vivo bovine intervertebral discs (N = 12) on a 3 T clinical MRI scanner. The sodium MR images were used to calculate effective nucleus pulposus fixed-charge-density (mean = 138.2 ± 27.6 mM) and subsequently osmotic pressure (mean = 0.53 ± 0.18 atm), whereas the T(1ρ) -weighted images were used to compute T(1ρ) relaxation maps. A significant linear correlation (R = 0.56, P < 0.01) between nucleus pulposus fixed-charge-density and T(1ρ) relaxation time constant was observed. More importantly, a significant power correlation (R = 0.72, P < 0.01) between nucleus pulposus osmotic pressure as predicted by sodium MRI and T(1ρ) relaxation time constant was also observed. The current clinical method for assessing disc pressure is discography, which is an invasive procedure that has been shown to have negative effects on disc biomechanical and biochemical properties. In contrast, T(1ρ) MRI is noninvasive and can be easily implemented in a clinical setting due to its superior signal-to-noise ratio compared with sodium MRI. Therefore, T(1ρ) MRI may serve as a noninvasive clinical tool for the longitudinal evaluation of disc osmotic pressure. Copyright © 2010 Wiley-Liss, Inc.

  11. Rapid and simple determination of T1 relaxation times in time-domain NMR by Continuous Wave Free Precession sequence

    NASA Astrophysics Data System (ADS)

    Moraes, Tiago Bueno; Monaretto, Tatiana; Colnago, Luiz Alberto

    2016-09-01

    Longitudinal (T1) and transverse (T2) relaxation times have been widely used in time-domain NMR (TD-NMR) to determine several physicochemical properties of petroleum, polymers, and food products. The measurement of T2 through the CPMG pulse sequence has been used in most of these applications because it denotes a rapid, robust method. On the other hand, T1 has been occasionally used in TD-NMR due to the long measurement time required to collect multiple points along the T1 relaxation curve. Recently, several rapid methods to measure T1 have been proposed. Those methods based upon single shot, known as Continuous Wave Free Precession (CWFP) pulse sequences, have been employed in the simultaneous measurement of T1 and T2 in a rapid fashion. However, these sequences can be used exclusively in instrument featuring short dead time because the magnitude of the signal at thermal equilibrium is required. In this paper, we demonstrate that a special CWFP sequence with a low flip angle can be a simple and rapid method to measure T1 regardless of instruments dead time. Experimental results confirmed that the method called CWFP-T1 may be used to measure both single T1 value and T1 distribution in heterogeneous samples. Therefore, CWFP-T1 sequence can be a feasible alternative to CPMG in the determination of physicochemical properties, particularly in processes where fast protocols are requested such as industrial applications.

  12. Proton Dynamics in the Anti-ferroelectric CsH3(SeO3)2 by using 1H NMR Measurements

    NASA Astrophysics Data System (ADS)

    Lee, Moohee; Ndiaye, B.; Kang, K.; Kim, H.; Sim, J.; Lim, Ae Ran

    2014-03-01

    1H NMR techniques have been employed on the anti-ferroelectric CsH3(SeO3)2 to measure spectrum, shift, T1 and T2 from 300 K down to 80 K at 4.85 T. The 1H NMR spectrum at 300 K shows a composite structure; one dominant broad peak and two small narrow peaks. From the temperature dependences of both intensity and T1 for each peak, we identify that the narrow peaks come from rapidly moving protons whereas the broad peaks originate from rigid protons. The spectra below 200 K show several peaks associated with six nonequivalent proton sites and also the T1 decays show a non-exponential curve coming from many proton sites. T1 is very long even at 300 K and becomes even longer at low temperature. By analyzing T1 decays with T1S and T1L, we confirm that 1/T1(T) show an activated behavior; the short component originates from proton dynamics with activation energy of ~ 140 K and the long component is associated with that of ~ 100 K. Further analysis suggests that some protons show an abrupt change in both shift and T1L across Tc and may be responsible for the phase transition.

  13. QIN: Practical Considerations in T1 Mapping of Prostate for Dynamic Contrast Enhancement Pharmacokinetic Analyses

    PubMed Central

    Fennessy, Fiona M; Fedorov, Andriy; Gupta, Sandeep N; Schmidt, Ehud J; Tempany, Clare M; Mulkern, Robert V

    2012-01-01

    There are many challenges in developing robust imaging biomarkers that can be reliably applied in a clinical trial setting. In the case of Dynamic Contrast Enhanced (DCE) MRI, one such challenge is to obtain accurate pre-contrast T1 maps for subsequent use in two-compartment pharmacokinetic models commonly used to fit the MR enhancement time courses. In the prostate, a convenient and common approach for this task has been to use the same 3D SPGR sequence used to collect the DCE data, but with variable flip angles (VFA’s) to collect data suitable for T1 mapping prior to contrast injection. However, inhomogeneous radiofrequency conditions within the prostate have been found to adversely affect the accuracy of this technique. Herein we demonstrate the sensitivity of DCE pharmacokinetic parameters to pre-contrast T1 values and examine methods to improve the accuracy of T1 mapping with flip angle corrected VFA SPGR methods, comparing T1 maps from such methods with reference T1 maps generated with saturation recovery experiments performed with fast spin echo (FSE) sequences. PMID:22898681

  14. Voltage-dependent gating rearrangements in the intracellular T1-T1 interface of a K+ channel.

    PubMed

    Wang, Guangyu; Covarrubias, Manuel

    2006-04-01

    The intracellular tetramerization domain (T1) of most eukaryotic voltage-gated potassium channels (Kv channels) exists as a "hanging gondola" below the transmembrane regions that directly control activation gating via the electromechanical coupling between the S4 voltage sensor and the main S6 gate. However, much less is known about the putative contribution of the T1 domain to Kv channel gating. This possibility is mechanistically intriguing because the T1-S1 linker connects the T1 domain to the voltage-sensing domain. Previously, we demonstrated that thiol-specific reagents inhibit Kv4.1 channels by reacting in a state-dependent manner with native Zn(2+) site thiolate groups in the T1-T1 interface; therefore, we concluded that the T1-T1 interface is functionally active and not protected by Zn(2+) (Wang, G., M. Shahidullah, C.A. Rocha, C. Strang, P.J. Pfaffinger, and M. Covarrubias. 2005. J. Gen. Physiol. 126:55-69). Here, we co-expressed Kv4.1 channels and auxiliary subunits (KChIP-1 and DPPX-S) to investigate the state and voltage dependence of the accessibility of MTSET to the three interfacial cysteines in the T1 domain. The results showed that the average MTSET modification rate constant (k(MTSET)) is dramatically enhanced in the activated state relative to the resting and inactivated states (approximately 260- and approximately 47-fold, respectively). Crucially, under three separate conditions that produce distinct activation profiles, k(MTSET) is steeply voltage dependent in a manner that is precisely correlated with the peak conductance-voltage relations. These observations strongly suggest that Kv4 channel gating is tightly coupled to voltage-dependent accessibility changes of native T1 cysteines in the intersubunit Zn(2+) site. Furthermore, cross-linking of cysteine pairs across the T1-T1 interface induced substantial inhibition of the channel, which supports the functionally dynamic role of T1 in channel gating. Therefore, we conclude that the complex

  15. Proton-detected 3D (15)N/(1)H/(1)H isotropic/anisotropic/isotropic chemical shift correlation solid-state NMR at 70kHz MAS.

    PubMed

    Pandey, Manoj Kumar; Yarava, Jayasubba Reddy; Zhang, Rongchun; Ramamoorthy, Ayyalusamy; Nishiyama, Yusuke

    2016-01-01

    Chemical shift anisotropy (CSA) tensors offer a wealth of information for structural and dynamics studies of a variety of chemical and biological systems. In particular, CSA of amide protons can provide piercing insights into hydrogen-bonding interactions that vary with the backbone conformation of a protein and dynamics. However, the narrow span of amide proton resonances makes it very difficult to measure (1)H CSAs of proteins even by using the recently proposed 2D (1)H/(1)H anisotropic/isotropic chemical shift (CSA/CS) correlation technique. Such difficulties due to overlapping proton resonances can in general be overcome by utilizing the broad span of isotropic chemical shifts of low-gamma nuclei like (15)N. In this context, we demonstrate a proton-detected 3D (15)N/(1)H/(1)H CS/CSA/CS correlation experiment at fast MAS frequency (70kHz) to measure (1)H CSA values of unresolved amide protons of N-acetyl-(15)N-l-valyl-(15)N-l-leucine (NAVL).

  16. Conformational evaluation and detailed 1H and 13C NMR assignments of eremophilanolides.

    PubMed

    Burgueño-Tapia, Eleuterio; Hernández, Luis R; Reséndiz-Villalobos, Adriana Y; Joseph-Nathan, Pedro

    2004-10-01

    Extensive application of 1D and 2D NMR methodology, combined with molecular modeling, allowed the complete 1H and 13C NMR assignments of eremophilanolides from Senecio toluccanus. Comparison of the experimental 1H, 1H coupling constant values with those generated employing a generalized Karplus-type relationship, using dihedral angles extracted from MMX and DFT calculations, revealed that the epoxidized eremophilanolides 1 and 2 show conformational rigidity at room temperature, whereas molecules 3-6, containing an isolated double bond, are conformationally mobile.

  17. 1H-NMR study of the spin dynamics of fine superparamagnetic nanoparticles

    SciTech Connect

    Bordonali, L.; Furukawa, Y.; Kraken, M.; Litterst, F.J.; Sangregorio, C.; Casula, M.F.; Lascialfari, A.

    2012-05-25

    We report a broadband 1H-NMR study of the temperature spin dynamics of nearly monodisperse dextran-coated γ-Fe2O3 magnetic nanoparticles. We observed a maximum in T1−1(T) that decreases in amplitude and shifts toward higher temperatures with increasing field. We suggest that this is related to the progressive superparamagnetic spin blocking of the ferrite core. The data can be explained by assuming a single electronic spin-spin correlation time and introducing a field-dependent distribution of anisotropy energy barriers.

  18. T1ρ Magnetic Resonance Imaging to Assess Cartilage Damage After Primary Shoulder Dislocation

    PubMed Central

    Saxena, Vishal; D'Aquilla, Kevin; Marcoon, Shannon; Krishnamoorthy, Guruprasad; Gordon, Joshua A.; Carey, James L.; Borthakur, Ari; Kneeland, J. Bruce; Kelly, John D.; Reddy, Ravinder; Sennett, Brian J.

    2017-01-01

    Background Patients who suffer anterior shoulder dislocations are at higher risk of developing glenohumeral arthropathy, but little is known about the initial cartilage damage after a primary shoulder dislocation. T1ρ is a magnetic resonance imaging (MRI) technique that allows quantification of cartilage proteoglycan content and can detect physiologic changes in articular cartilage. Purpose To establish baseline T1ρ MRI values for glenoid and humeral head cartilage, determine if T1ρ MRI can detect glenohumeral cartilage damage following traumatic primary shoulder dislocation, and assess for patterns in cartilage damage in anterior shoulder dislocation. Study Design Prospective cohort study Methods Nine male patients (mean age 32.0 years, range 20-59) who sustained first-time anterior shoulder dislocations underwent 3T T1ρ MRI. Five healthy controls (mean age 27.4 years, range 24-30) without prior dislocation or glenohumeral arthritis also underwent 3T T1ρ MRI. The T1ρ relaxation constant was determined for the entire glenoid and humeral head for dislocation patients and healthy controls. The glenoid and humeral head were divided into nine zones, and T1ρ values were determined for each zone in dislocated and control shoulders to identify patterns in cartilage damage in dislocated shoulders. Results Average overall T1ρ values for humeral head cartilage in dislocated shoulders were significantly greater than controls (41.7ms ± 3.9 versus 38.4ms ± 0.6, respectively; p = 0.03). However, average overall T1ρ values for glenoid cartilage were not significantly different in dislocated shoulders compared to controls (44.0ms ± 3.3 versus 44.6ms ± 2.4, respectively; p = 0.40), suggesting worse damage to humeral head cartilage. T1ρ values in the posterior-middle humeral head were higher in dislocation patients compared to controls (41.5ms ± 3.8 versus 38.2ms ± 2.2, respectively; p = 0.021) and trended toward significance in the posterior-superior and middle

  19. Repeatability of magnetic resonance fingerprinting T1 and T2 estimates assessed using the ISMRM/NIST MRI system phantom.

    PubMed

    Jiang, Yun; Ma, Dan; Keenan, Kathryn E; Stupic, Karl F; Gulani, Vikas; Griswold, Mark A

    2017-10-01

    The purpose of this study was to evaluate accuracy and repeatability of T1 and T2 estimates of a MR fingerprinting (MRF) method using the ISMRM/NIST MRI system phantom. The ISMRM/NIST MRI system phantom contains multiple compartments with standardized T1 , T2 , and proton density values. Conventional inversion-recovery spin echo and spin echo methods were used to characterize the T1 and T2 values in the phantom. The phantom was scanned using the MRF-FISP method over 34 consecutive days. The mean T1 and T2 values were compared with the values from the spin echo methods. The repeatability was characterized as the coefficient of variation of the measurements over 34 days. T1 and T2 values from MRF-FISP over 34 days showed a strong linear correlation with the measurements from the spin echo methods (R(2)  = 0.999 for T1 ; R(2)  = 0.996 for T2 ). The MRF estimates over the wide ranges of T1 and T2 values have less than 5% variation, except for the shortest T2 relaxation times where the method still maintains less than 8% variation. MRF measurements of T1 and T2 are highly repeatable over time and across wide ranges of T1 and T2 values. Magn Reson Med 78:1452-1457, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

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

    PubMed

    Shen, Zhi-Wei; Cao, Zhen; You, Ke-Zeng; Yang, Zhong-Xian; Xiao, Ye-Yu; Cheng, Xiao-Fang; Chen, Yao-Wen; Wu, Ren-Hua

    2012-03-14

    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). 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 sequence-localized 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. 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). 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

  1. 7-T (1) H MRS with adiabatic refocusing at short TE using radiofrequency focusing with a dual-channel volume transmit coil.

    PubMed

    Boer, V O; van Lier, A L H M W; Hoogduin, J M; Wijnen, J P; Luijten, P R; Klomp, D W J

    2011-11-01

    In vivo MRS of the human brain at ultrahigh field allows for the identification of a large number of metabolites at higher spatial resolutions than currently possible in clinical practice. However, the in vivo localization of single-voxel spectroscopy has been shown to be challenging at ultrahigh field because of the low bandwidth of refocusing radiofrequency (RF) pulses. Thus far, the proposed methods for localized MRS at 7 T suffer from long TE, inherent signal loss and/or a large chemical shift displacement artifact that causes a spatial displacement between resonances, and results in a decreased efficiency in editing sequences. In this work, we show that, by driving a standard volume coil with two RF amplifiers, focusing the B 1+ field in a certain location and using high-bandwidth adiabatic refocusing pulses, a semi-LASER (semi-localized by adiabatic selective refocusing) localization is feasible at short TE in the human brain with full signal acquisition and a low chemical shift displacement artifact at 7 T. Copyright © 2011 John Wiley & Sons, Ltd.

  2. Increased Brain Lactate During Depressive Episodes and Reversal Effects by Lithium Monotherapy in Drug-Naive Bipolar Disorder: A 3-T 1H-MRS Study.

    PubMed

    Machado-Vieira, Rodrigo; Zanetti, Marcus V; Otaduy, Maria C; De Sousa, Rafael T; Soeiro-de-Souza, Marcio G; Costa, Alana C; Carvalho, Andre F; Leite, Claudia C; Busatto, Geraldo F; Zarate, Carlos A; Gattaz, Wagner F

    2017-02-01

    Mitochondrial dysfunction and energy metabolism impairment are key components in the pathophysiology of bipolar disorder (BD) and may involve a shift from aerobic to anaerobic metabolism. Measurement of brain lactate in vivo using proton magnetic resonance spectroscopy (H-MRS) represents an important tool to evaluate mitochondrial and metabolic dysfunction during mood episodes, as well as to monitor treatment response. To date, very few studies have quantified brain lactate in BD. In addition, no study has longitudinally evaluated lactate using H-MRS during depressive episodes or its association with mood stabilizer therapy. This study aimed to evaluate cingulate cortex (CC) lactate using 3-T H-MRS during acute depressive episodes in BD and the possible effects induced by lithium monotherapy. Twenty medication-free outpatients with short length of BD (80% drug-naive) in a current major depressive episode were matched with control subjects. Patients were treated for 6 weeks with lithium monotherapy at therapeutic doses in an open-label trial (blood level, 0.48 ± 0.19 mmol/L). Cingulate cortex lactate was measured before (week 0) and after lithium therapy (week 6) using H-MRS. Antidepressant efficacy was assessed with the 21-item Hamilton Depression Rating Scale as the primary outcome. Subjects with BD depression showed a significantly higher CC lactate in comparison to control subjects. Furthermore, a significant decrease in CC lactate was observed after 6 weeks of lithium treatment compared with baseline (P = 0.002). CC Lactate levels was associated with family history of mood disorders and plasma lithium levels. This is the first report of increased CC lactate in patients with bipolar depression and lower levels after lithium monotherapy for 6 weeks. These findings indicate a shift to anaerobic metabolism and a role for lactate as a state marker during mood episodes. Energy and redox dysfunction may represent key targets for lithium's therapeutic actions.

  3. Comparison of direct (13)C and indirect (1)H-[(13)C] MR detection methods for the study of dynamic metabolic turnover in the human brain.

    PubMed

    Chen, Hao; De Feyter, Henk M; Brown, Peter B; Rothman, Douglas L; Cai, Shuhui; de Graaf, Robin A

    2017-10-01

    A wide range of direct (13)C and indirect (1)H-[(13)C] MR detection methods exist to probe dynamic metabolic pathways in the human brain. Choosing an optimal detection method is difficult as sequence-specific features regarding spatial localization, broadband decoupling, spectral resolution, power requirements and sensitivity complicate a straightforward comparison. Here we combine density matrix simulations with experimentally determined values for intrinsic (1)H and (13)C sensitivity, T1 and T2 relaxation and transmit efficiency to allow selection of an optimal (13)C MR detection method for a given application and magnetic field. The indirect proton-observed, carbon-edited (POCE) detection method provides the highest accuracy at reasonable RF power deposition both at 4T and 7T. The various polarization transfer methods all have comparable performances, but may become infeasible at 7T due to the high RF power deposition. 2D MR methods have limited value for the metabolites considered (primarily glutamate, glutamine and γ-amino butyric acid (GABA)), but may prove valuable when additional information can be extracted, such as isotopomers or lipid composition. While providing the lowest accuracy, the detection of non-protonated carbons is the simplest to implement with the lowest RF power deposition. The magnetic field homogeneity is one of the most important parameters affecting the detection accuracy for all metabolites and all acquisition methods. Copyright © 2017. Published by Elsevier Inc.

  4. Genetic Variation in Myosin 1H Contributes to Mandibular Prognathism

    PubMed Central

    Tassopoulou-Fishell, Maria; Deeley, Kathleen; Harvey, Erika M.; Sciote, James; Vieira, Alexandre R.

    2013-01-01

    Introduction Several candidate loci have been suggested as influencing mandibular prognathism (1p22.1, 1p22.2, 1p36, 3q26.2, 5p13-p12, 6q25, 11q22.2-q22.3, 12q23, 12q13.13, and 19p13.2). The goal of this study was to replicate these results in a well-characterized homogeneous sample set. Methods Thirty-three single nucleotide polymorphisms spanning all candidate regions were studied in 44 prognathic and 35 Class I subjects from the University of Pittsburgh School of Dental Medicine Dental Registry and DNA Repository. The 44 mandibular prognathism subjects had an average age of 18.4 years, 31 were females and 13 males, and 24 were White, 15 African American, two Hispanic, and three Asian. The 35 Class I subjects had an average age of 17.6 years, 27 were females and 9 males, and 27 were White, six African Americans, one Hispanic, and two Asian. Skeletal mandibular prognathism diagnosis included cephalometric values indicative of Class III such as ANB smaller than two degrees, negative Witts appraisal, and positive A–B plane. Additional mandibular prognathism criteria included negative OJ and visually prognathic (concave) profile as determined by the subject's clinical evaluation. Orthognathic subjects without jaw deformations were used as a comparison group. Mandibular prognathism and orthognathic subjects were matched based on race, sex and age. Genetic markers were tested by polymerase chain reaction using TaqMan chemistry. Chi-square and Fisher exact tests were used to determine overrepresentation of marker allele with alpha of 0.05. Results An association was unveiled between a marker in MYO1H (rs10850110) and the mandibular prognathism phenotype (p=0.03). MYO1H is a Class-I myosin that is in a different protein group than the myosin isoforms of muscle sarcomeres, which are the basis of skeletal muscle fiber typing. Class I myosins are necessary for cell motility, phagocytosis and vesicle transport. Conclusions More strict clinical definitions may increase

  5. Purification of ribonuclease T1 by diethylaminoethylcellulose chromatography

    PubMed Central

    Fields, Robert; Dixon, Henry B. F.; Law, Gillian R.; Yui, Chie

    1971-01-01

    A procedure is described for isolating the enzyme ribonuclease T1 from Takadiastase, an extract of the mould Aspergillus oryzae. It involves an initial concentration of the enzyme by adsorption on DEAE-cellulose followed by gradient elution. Later the enzyme is chromatographed on the same adsorbent with an eluent of constant composition. Yields of 350–380mg of ribonuclease T1 from 500g of Takadiastase were obtained. ImagesFig. 4. PMID:5114970

  6. Functional t1ρ imaging in panic disorder.

    PubMed

    Magnotta, Vincent A; Johnson, Casey P; Follmer, Robin; Wemmie, John A

    2014-06-01

    Abnormal brain pH has been suggested to play a critical role in panic disorder. To investigate this possibility, we employed a pH-sensitive magnetic resonance (MR) imaging strategy (T1 relaxation in the rotating frame [T1ρ]) and conventional blood oxygen level-dependent (BOLD) imaging. Thirteen panic disorder participants and 13 matched control subjects were enrolled in the study. T1ρ and BOLD were used to study the functional response to a visual flashing checkerboard and their relationship to panic symptoms assessed using the Beck Anxiety Inventory. In response to visual stimulation, T1ρ imaging revealed a significantly greater increase in the visual cortex of panic disorder participants. T1ρ also detected a stimulus-evoked decrease in the anterior cingulate cortex. Blood oxygen level-dependent imaging detected no functional differences between groups. The correspondence between panic symptoms and functional T1ρ response identified significant relationships within the left inferior parietal lobe, left middle temporal gyrus, and right insula. No relationships were found between panic symptoms and the BOLD signal. The data suggest greater activity-evoked T1ρ changes in the visual cortex and anterior cingulate cortex of panic disorder participants. These observations are consistent with a pH dysregulation in panic disorder. In addition, our data suggest that T1ρ imaging may provide information about panic disorder that is distinct from conventional BOLD imaging and may reflect abnormalities in pH and/or brain metabolism. © 2013 Society of Biological Psychiatry Published by Society of Biological Psychiatry All rights reserved.

  7. Neurochemical profile of patients with type 1 diabetes measured by 1H-MRS at 4 T

    PubMed Central

    Mangia, Silvia; Kumar, Anjali F; Moheet, Amir A; Roberts, Rachel J; Eberly, Lynn E; Seaquist, Elizabeth R; Tkáč, Ivan

    2013-01-01

    The impact of type 1 diabetes mellitus (T1DM) on a comprehensive neurochemical profile of the human brain has not been reported yet. Our previous proton magnetic resonance spectroscopy (1H-MRS) studies on T1DM were focused exclusively on the assessment of brain glucose levels. In this study, we reexamined our previously acquired data to investigate concentration differences of a broad range of neurochemicals in T1DM subjects relative to nondiabetic controls. We selected MRS data from 13 subjects (4 F/9 M, age=41±11 years, body mass index=26±3 kg/m2) with well-controlled T1DM (disease duration=22±12 years, A1C=7.5%±2.0%) and 32 nondiabetic controls (14 F/18 M, age=36±10 years, body mass index=27±6 kg/m2) acquired during a hyperglycemic clamp (target [Glc]plasma=300±15 mg/dL). The 1H-MR spectra were collected from two 15.6-mL voxels localized in gray-matter-rich occipital lobe and in white-matter-rich parieto-occipital region using ultra-short echo-time STEAM at 4 T. LCModel analysis allowed reliable quantification of 17 brain metabolites. Lower levels of N-acetylaspartate (by 6%, P=0.007) and glutamate (by 6%, P=0.045) were observed in the gray matter of T1DM patients as compared with controls, which might indicate a partial neuronal loss or dysfunction as a consequence of long-term T1DM. No other differences in metabolites were observed between subjects with T1DM and controls. PMID:23403373

  8. Post-contrast myocardial T(1) and ECV disagree in a longitudinal canine study.

    PubMed

    Koopmann, Matthias; Hong, KyungPyo; Kholmovski, Eugene G; Huang, Eric C; Hu, Nan; Ying, Jian; Levenson, Richard; Vijayakumar, Sathya; Dosdall, Derek J; Ranjan, Ravi; Kim, Daniel

    2014-08-01

    Both post-contrast myocardial T1 and extracellular volume (ECV) measurements have been associated with diffuse interstitial fibrosis. The cardiovascular magnetic resonance (CMR) field is migrating towards ECV, because it is largely insensitive to confounders that affect post-contrast myocardial T1 . Despite the theoretical advantages of myocardial ECV over post-contrast myocardial T1 , systematic experimental studies comparing the two measurements are largely lacking. We sought to measure the temporal changes in post-contrast myocardial T1 and ECV in an established canine model with chronic atrial fibrillation. Seventeen mongrel dogs, implanted with a pacemaker to induce chronic atrial fibrillation via rapid atrial pacing, were scanned multiple times for a total of 46 CMR scans at 3T. These dogs with different disease durations (0-22 months) were part of a separate longitudinal study aimed at studying the relationship between AF and pathophysiology. In each animal, we measured native and post-contrast T1 values and hematocrit. Temporal changes in post-contrast myocardial T1 and ECV, as well as other CMR parameters, were modeled with linear mixed effect models to account for repeated measurements over disease duration. In 17 animals, post-contrast myocardial T1 decreased significantly from 872 to 698 ms (p < 0.001), which corresponds to a 24.9% relative reduction. In contrast, ECV increased from 21.0 to 22.0% (p = 0.38), which corresponds to only a 4.5% relative increase. To partially investigate this discrepancy, we quantified collagen volume fraction (CVF) in post-mortem heart tissues of six canines sacrificed at different disease durations (0-22 months). CVF quantified by histology increased from 0.9 to 1.9% (p = 0.56), which agrees better with ECV than with post-contrast myocardial T1 . This study shows that post-contrast myocardial T1 and ECV may disagree in a longitudinal canine study. A more comprehensive study, including histologic, cardiac, and renal

  9. Measurement of Myocardial T1ρ with a Motion Corrected, Parametric Mapping Sequence in Humans

    PubMed Central

    Shahid, Mohammed; Han, Yuchi; Witschey, Walter R. T.

    2016-01-01

    Purpose To develop a robust T1ρ magnetic resonance imaging (MRI) sequence for assessment of myocardial disease in humans. Materials and Methods We developed a breath-held T1ρ mapping method using a single-shot, T1ρ-prepared balanced steady-state free-precession (bSSFP) sequence. The magnetization trajectory was simulated to identify sources of T1ρ error. To limit motion artifacts, an optical flow-based image registration method was used to align T1ρ images. The reproducibility and accuracy of these methods was assessed in phantoms and 10 healthy subjects. Results are shown in 1 patient with pre-ventricular contractions (PVCs), 1 patient with chronic myocardial infarction (MI) and 2 patients with hypertrophic cardiomyopathy (HCM). Results In phantoms, the mean bias was 1.0 ± 2.7 msec (100 msec phantom) and 0.9 ± 0.9 msec (60 msec phantom) at 60 bpm and 2.2 ± 3.2 msec (100 msec) and 1.4 ± 0.9 msec (60 msec) at 80 bpm. The coefficient of variation (COV) was 2.2 (100 msec) and 1.3 (60 msec) at 60 bpm and 2.6 (100 msec) and 1.4 (60 msec) at 80 bpm. Motion correction improved the alignment of T1ρ images in subjects, as determined by the increase in Dice Score Coefficient (DSC) from 0.76 to 0.88. T1ρ reproducibility was high (COV < 0.05, intra-class correlation coefficient (ICC) = 0.85–0.97). Mean myocardial T1ρ value in healthy subjects was 63.5 ± 4.6 msec. There was good correspondence between late-gadolinium enhanced (LGE) MRI and increased T1ρ relaxation times in patients. Conclusion Single-shot, motion corrected, spin echo, spin lock MRI permits 2D T1ρ mapping in a breath-hold with good accuracy and precision. PMID:27003184

  10. Intramuscular adipose tissue determined by T1-weighted MRI at 3T primarily reflects extramyocellular lipids.

    PubMed

    Akima, Hiroshi; Hioki, Maya; Yoshiko, Akito; Koike, Teruhiko; Sakakibara, Hisataka; Takahashi, Hideyuki; Oshida, Yoshiharu

    2016-05-01

    The purpose of this study was to assess relationships between intramuscular adipose tissue (IntraMAT) content determined by MRI and intramyocellular lipids (IMCL) and extramyocellular lipids (EMCL) determined by (1)H magnetic resonance spectroscopy ((1)H MRS) or echo intensity determined by B-mode ultrasonography of human skeletal muscles. Thirty young and elderly men and women were included. T1-weighted MRI was taken from the right mid-thigh to measure IntraMAT content of the vastus lateralis (VL) and biceps femoris (BF) using a histogram shape-based thresholding technique. IMCL and EMCL were measured from the VL and BF at the right mid-thigh using (1)H MRS. Ultrasonographic images were taken from the VL and BF of the right mid-thigh to measure echo intensity based on gray-scale level for quantitative analysis. There was a significant correlation between IntraMAT content by MRI and EMCL of the VL and BF (VL, r=0.506, P<0.01; BF, r=0.591, P<0.001) and between echo intensity and EMCL of the VL and BF (VL, r=0.485, P<0.05; BF, r=0.648, P<0.01). IntraMAT content was also significantly correlated with echo intensity of the VL and BF (VL, r=0.404, P<0.05; BF, r=0.493, P<0.01). Our study suggests that IntraMAT content determined by T1-weighted MRI at 3T primarily reflects extramyocellular lipids, not intramyocellular lipids, in human skeletal muscles. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Rapid volumetric T1 mapping of the abdomen using three-dimensional through-time spiral GRAPPA.

    PubMed

    Chen, Yong; Lee, Gregory R; Aandal, Gunhild; Badve, Chaitra; Wright, Katherine L; Griswold, Mark A; Seiberlich, Nicole; Gulani, Vikas

    2016-04-01

    To develop an ultrafast T1 mapping method for high-resolution, volumetric T1 measurements in the abdomen. The Look-Locker method was combined with a stack-of-spirals acquisition accelerated using three-dimensional (3D) through-time spiral GRAPPA reconstruction for fast data acquisition. A segmented k-space acquisition scheme was proposed and the time delay between segments for the recovery of longitudinal magnetization was optimized using Bloch equation simulations. The accuracy of this method was validated in a phantom experiment and in vivo T1 measurements were performed with 35 asymptomatic subjects on both 1.5 Tesla (T) and 3T MRI systems. Phantom experiments yielded close agreement between the proposed method and gold standard measurements for a large range of T1 values (200 to 1600 ms). The in vivo results further demonstrate that high-resolution T1 maps (2 × 2 × 4 mm(3)) for 32 slices can be achieved in a single clinically feasible breath-hold of approximately 20 s. The T1 values for multiple organs and tissues in the abdomen are in agreement with the published literature. A high-resolution 3D abdominal T1 mapping technique was developed, which allows fast and accurate T1 mapping of multiple abdominal organs and tissues in a single breath-hold. © 2015 Wiley Periodicals, Inc.

  12. On the selection of sampling points for myocardial T1 mapping.

    PubMed

    Akçakaya, Mehmet; Weingärtner, Sebastian; Roujol, Sébastien; Nezafat, Reza

    2015-05-01

    To provide a method for the optimal selection of sampling points for myocardial T1 mapping, and to evaluate how this selection affects the precision. The Cramér-Rao lower bound on the variance of the unbiased estimator was derived for the sampling of the longitudinal magnetization curve, as a function of T1 , signal-to-noise ratio, and noise mean. The bound was then minimized numerically over a search space of possible sampling points to find the optimal selection of sampling points. Numerical simulations were carried out for a saturation recovery-based T1 mapping sequence, comparing the proposed point selection method to a uniform distribution of sampling points along the recovery curve for various T1 ranges of interest, as well as number of sampling points. Phantom imaging was performed to replicate the scenarios in numerical simulations. In vivo imaging for myocardial T1 mapping was also performed in healthy subjects. Numerical simulations show that the precision can be improved by 13-25% by selecting the sampling points according to the target T1 values of interest. Results of the phantom imaging were not significantly different than the theoretical predictions for different sampling strategies, signal-to-noise ratio and number of sampling points. In vivo imaging showed precision can be improved in myocardial T1 mapping using the proposed point selection method as predicted by theory. The framework presented can be used to select the sampling points to improve the precision without penalties on accuracy or scan time. © 2014 Wiley Periodicals, Inc.

  13. A feasible and automatic free tool for T1 and ECV mapping.

    PubMed

    Altabella, Luisa; Borrazzo, Cristian; Carnì, Marco; Galea, Nicola; Francone, Marco; Fiorelli, Andrea; Di Castro, Elisabetta; Catalano, Carlo; Carbone, Iacopo

    2017-01-01

    Cardiac magnetic resonance (CMR) is a useful non-invasive tool for characterizing tissues and detecting myocardial fibrosis and edema. Estimation of extracellular volume fraction (ECV) using T1 sequences is emerging as an accurate biomarker in cardiac diseases associated with diffuse fibrosis. In this study, automatic software for T1 and ECV map generation consisting of an executable file was developed and validated using phantom and human data. T1 mapping was performed in phantoms and 30 subjects (22 patients and 8 healthy subjects) on a 1.5T MR scanner using the modified Look-Locker inversion-recovery (MOLLI) sequence prototype before and 15 min after contrast agent administration. T1 maps were generated using a Fast Nonlinear Least Squares algorithm. Myocardial ECV maps were generated using both pre- and post-contrast T1 image registration and automatic extraction of blood relaxation rates. Using our software, pre- and post-contrast T1 maps were obtained in phantoms and healthy subjects resulting in a robust and reliable quantification as compared to reference software. Coregistration of pre- and post-contrast images improved the quality of ECV maps. Mean ECV value in healthy subjects was 24.5%±2.5%. This study demonstrated that it is possible to obtain accurate T1 maps and informative ECV maps using our software. Pixel-wise ECV maps obtained with this automatic software made it possible to visualize and evaluate the extent and severity of ECV alterations. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  14. T1 mapping and survival in systemic light-chain amyloidosis

    PubMed Central

    Banypersad, Sanjay M.; Fontana, Marianna; Maestrini, Viviana; Sado, Daniel M.; Captur, Gabriella; Petrie, Aviva; Piechnik, Stefan K.; Whelan, Carol J.; Herrey, Anna S.; Gillmore, Julian D.; Lachmann, Helen J.; Wechalekar, Ashutosh D.; Hawkins, Philip N.; Moon, James C.

    2015-01-01

    Aims To assess the prognostic value of myocardial pre-contrast T1 and extracellular volume (ECV) in systemic amyloid light-chain (AL) amyloidosis using cardiovascular magnetic resonance (CMR) T1 mapping. Methods and results One hundred patients underwent CMR and T1 mapping pre- and post-contrast. Myocardial ECV was calculated at contrast equilibrium (ECVi) and 15 min post-bolus (ECVb). Fifty-four healthy volunteers served as controls. Patients were followed up for a median duration of 23 months and survival analyses were performed. Mean ECVi was raised in amyloid (0.44 ± 0.12) as was ECVb (mean 0.44 ± 0.12) compared with healthy volunteers (0.25 ± 0.02), P < 0.001. Native pre-contrast T1 was raised in amyloid (mean 1080 ± 87 ms vs. 954 ± 34 ms, P < 0.001). All three correlated with pre-test probability of cardiac involvement, cardiac biomarkers, and systolic and diastolic dysfunction. During follow-up, 25 deaths occurred. An ECVi of >0.45 carried a hazard ratio (HR) for death of 3.84 [95% confidence interval (CI): 1.53–9.61], P = 0.004 and pre-contrast T1 of >1044 ms = HR 5.39 (95% CI: 1.24–23.4), P = 0.02. Extracellular volume after primed infusion and ECVb performed similarly. Isolated post-contrast T1 was non-predictive. In Cox regression models, ECVi was independently predictive of mortality (HR = 4.41, 95% CI: 1.35–14.4) after adjusting for E:E′, ejection fraction, diastolic dysfunction grade, and NT-proBNP. Conclusion Myocardial ECV (bolus or infusion technique) and pre-contrast T1 are biomarkers for cardiac AL amyloid and they predict mortality in systemic amyloidosis. PMID:25411195

  15. White matter fiber-based analysis of T1w/T2w ratio map

    NASA Astrophysics Data System (ADS)

    Chen, Haiwei; Budin, Francois; Noel, Jean; Prieto, Juan Carlos; Gilmore, John; Rasmussen, Jerod; Wadhwa, Pathik D.; Entringer, Sonja; Buss, Claudia; Styner, Martin

    2017-02-01

    Purpose: To develop, test, evaluate and apply a novel tool for the white matter fiber-based analysis of T1w/T2w ratio maps quantifying myelin content. Background: The cerebral white matter in the human brain develops from a mostly non-myelinated state to a nearly fully mature white matter myelination within the first few years of life. High resolution T1w/T2w ratio maps are believed to be effective in quantitatively estimating myelin content on a voxel-wise basis. We propose the use of a fiber-tract-based analysis of such T1w/T2w ratio data, as it allows us to separate fiber bundles that a common regional analysis imprecisely groups together, and to associate effects to specific tracts rather than large, broad regions. Methods: We developed an intuitive, open source tool to facilitate such fiber-based studies of T1w/T2w ratio maps. Via its Graphical User Interface (GUI) the tool is accessible to non-technical users. The framework uses calibrated T1w/T2w ratio maps and a prior fiber atlas as an input to generate profiles of T1w/T2w values. The resulting fiber profiles are used in a statistical analysis that performs along-tract functional statistical analysis. We applied this approach to a preliminary study of early brain development in neonates. Results: We developed an open-source tool for the fiber based analysis of T1w/T2w ratio maps and tested it in a study of brain development.

  16. Molecular Imaging of Tumors Using a Quantitative T1 Mapping Technique via Magnetic Resonance Imaging

    PubMed Central

    Herrmann, Kelsey; Johansen, Mette L.; Craig, Sonya E.; Vincent, Jason; Howell, Michael; Gao, Ying; Lu, Lan; Erokwu, Bernadette; Agnes, Richard S.; Lu, Zheng-Rong; Pokorski, Jonathan K.; Basilion, James; Gulani, Vikas; Griswold, Mark; Flask, Chris; Brady-Kalnay, Susann M.

    2015-01-01

    Magnetic resonance imaging (MRI) of glioblastoma multiforme (GBM) with molecular imaging agents would allow for the specific localization of brain tumors. Prior studies using T1-weighted MR imaging demonstrated that the SBK2-Tris-(Gd-DOTA)3 molecular imaging agent labeled heterotopic xenograft models of brain tumors more intensely than non-specific contrast agents using conventional T1-weighted imaging techniques. In this study, we used a dynamic quantitative T1 mapping strategy to more objectively compare intra-tumoral retention of the SBK2-Tris-(Gd-DOTA)3 agent over time in comparison to non-targeted control agents. Our results demonstrate that the targeted SBK2-Tris-(Gd-DOTA)3 agent, a scrambled-Tris-(Gd-DOTA)3 control agent, and the non-specific clinical contrast agent Optimark™ all enhanced flank tumors of human glioma cells with similar maximal changes on T1 mapping. However, the retention of the agents differs. The non-specific agents show significant recovery within 20 min by an increase in T1 while the specific agent SBK2-Tris-(Gd-DOTA)3 is retained in the tumors and shows little recovery over 60 min. The retention effect is demonstrated by percent change in T1 values and slope calculations as well as by calculations of gadolinium concentration in tumor compared to muscle. Quantitative T1 mapping demonstrates the superior binding and retention in tumors of the SBK2-Tris-(Gd-DOTA)3 agent over time compared to the non-specific contrast agent currently in clinical use. PMID:26435847

  17. Relationship between aging and T1 relaxation time in deep gray matter: A voxel-based analysis.

    PubMed

    Okubo, Gosuke; Okada, Tomohisa; Yamamoto, Akira; Fushimi, Yasutaka; Okada, Tsutomu; Murata, Katsutoshi; Togashi, Kaori

    2017-09-01

    To investigate age-related changes in T1 relaxation time in deep gray matter structures in healthy volunteers using magnetization-prepared 2 rapid acquisition gradient echoes (MP2RAGE). In all, 70 healthy volunteers (aged 20-76, mean age 42.6 years) were scanned at 3T magnetic resonance imaging (MRI). A MP2RAGE sequence was employed to quantify T1 relaxation times. After the spatial normalization of T1 maps with the diffeomorphic anatomical registration using the exponentiated Lie algebra algorithm, voxel-based regression analysis was conducted. In addition, linear and quadratic regression analyses of regions of interest (ROIs) were also performed. With aging, voxel-based analysis (VBA) revealed significant T1 value decreases in the ventral-inferior putamen, nucleus accumbens, and amygdala, whereas T1 values significantly increased in the thalamus and white matter as well (P < 0.05 at cluster level, false discovery rate). ROI analysis revealed that T1 values in the nucleus accumbens linearly decreased with aging (P = 0.0016), supporting the VBA result. T1 values in the thalamus (P < 0.0001), substantia nigra (P = 0.0003), and globus pallidus (P < 0.0001) had a best fit to quadratic curves, with the minimum T1 values observed between 30 and 50 years of age. Age-related changes in T1 relaxation time vary by location in deep gray matter. 2 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:724-731. © 2017 International Society for Magnetic Resonance in Medicine.

  18. Magic angle effect plays a major role in both T1rho and T2 relaxation in articular cartilage.

    PubMed

    Shao, H; Pauli, C; Li, S; Ma, Y; Tadros, A S; Kavanaugh, A; Chang, E Y; Tang, G; Du, J

    2017-02-01

    To investigate the effect of sample orientation on T1rho and T2 values of articular cartilage in histologically confirmed normal and abnormal regions using a whole-body 3T scanner. Eight human cadaveric patellae were evaluated using a 2D CPMG sequence for T2 measurement as well as a 2D spin-locking prepared spiral sequence and a 3D magnetization-prepared angle-modulated partitioned-k-space spoiled gradient echo snapshots (3D MAPSS) sequence for T1rho measurement. Each sample was imaged at six angles from 0° to 100° relative to the B0 field. T2 and T1rho values were measured for three regions (medial, apex and lateral) with three layers (10% superficial, 60% middle, 30% deep). Multiple histopathologically confirmed normal and abnormal regions were used to evaluate the angular dependence of T2 and T1rho relaxation in articular cartilage. Our study demonstrated a strong magic angle effect for T1rho and T2 relaxation in articular cartilage, especially in the deeper layers of cartilage. On average, T2 values were increased by 231.8% (72.2% for superficial, 237.6% for middle, and 187.9% for deep layers) while T1rho values were increased by 92% (31.7% for superficial, 69% for middle, and 140% for deep layers) near the magic angle. Both normal and abnormal cartilage showed similar T1rho and T2 magic angle effect. Changes in T1rho and T2 values due to the magic angle effect can be several times more than that caused by degeneration, and this may significantly complicate the clinical application of T1rho and T2 as an early surrogate marker for degeneration. Copyright © 2017 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  19. [Estimation of T1 and T2 using general-purpose spreadsheet software].

    PubMed

    Kawamata, Wataru; Toyoshima, Hideto

    2009-03-20

    We performed an estimation of longitudinal (T1) and transverse relaxation (T2) time using the general-purpose spreadsheet software Microsoft Excel. The Excel tool "solver" is useful for the simultaneous estimation of both T1 and steady-state magnetization from the non-linear least square method. The estimation time is quick enough for the purpose. T1 and T2 estimated from handwritten semi-log plots were compared with the results from spreadsheet software from the viewpoint of accuracy using the phantom data. Although the data from handwritten plots include an estimation error of several percent among the subjects, the mean values are almost the same as compared with the data from spreadsheet software.

  20. Cerebral abnormalities: use of calculated T1 and T2 magnetic resonance images for diagnosis

    SciTech Connect

    Mills, C.M.; Crooks, L.E.; Kaufman, L.; Brant-Zawadzki, M.

    1984-01-01

    The potential clinical importance of T1 and T2 relaxation times in distinguishing normal and pathologic tissue with magnetic resonance (MR) is discussed and clinical examples of cerebral abnormalities are given. Five patients with cerebral infarction, 15 with multiple sclerosis, two with Wilson disease, and four with tumors were imaged. Hemorrhagic and ischemic cerebrovascular accidents were distinguished using the spin echo technique. In the patients with multiple sclerosis, lesions had prolonged T1 and T2 times, but the definition of plaque was limited by spatial resolution. No abnormalities in signal intensity were seen in the patient with Wilson disease who was no longer severly disabled; abnormal increased signal intensity in the basal ganglia was found in the second patient with Wilson disease. Four tumors produced abnormal T1 and T2 relaxation times but these values alone were not sufficient for tumor characterization.

  1. Molecular mobility of lyophilized poly(vinylpyrrolidone) and methylcellulose as determined by the laboratory and rotating frame spin-lattice relaxation times of 1H and 13C.

    PubMed

    Yoshioka, Sumie; Aso, Yukio; Kojima, Shigeo

    2003-11-01

    Laboratory- and rotating- frame spin-lattice relaxation times (T(1) and T(1rho)) of (1)H and (13)C in lyophilized poly(vinylpyrrolidone) (PVP) and methylcellulose (MC) are determined to examine feasibility of using T(1) and T(1rho) as a measure of molecular motions on large time scales related to the storage stability of lyophilized formulations. The T(1rho) of proton and carbon was found to reflect the mobility of PVP and MC backbones, indicating that it is useful as a measure of large-time-scale molecular motions. In contrast to the T(1rho), the T(1) of proton measured in the same temperature range reflected the mobility of PVP and MC side chains. The T(1) of proton may be useful as a measure of local molecular motions on a smaller-time-scale, although the measurement is interfered by moisture under some conditions. The temperature dependence of T(1) and T(1rho) indicated that methylene in the MC molecule had much higher mobility than that in the dextran molecule, also indicated that methylene in the PVP side chain had a higher mobility than that in the MC side chain.

  2. Comparison of T1 mapping techniques for ECV quantification. Histological validation and reproducibility of ShMOLLI versus multibreath-hold T1 quantification equilibrium contrast CMR.

    PubMed

    Fontana, Marianna; White, Steve K; Banypersad, Sanjay M; Sado, Daniel M; Maestrini, Viviana; Flett, Andrew S; Piechnik, Stefan K; Neubauer, Stefan; Roberts, Neil; Moon, James C

    2012-12-28

    Myocardial extracellular volume (ECV) is elevated in fibrosis or infiltration and can be quantified by measuring the haematocrit with pre and post contrast T1 at sufficient contrast equilibrium. Equilibrium CMR (EQ-CMR), using a bolus-infusion protocol, has been shown to provide robust measurements of ECV using a multibreath-hold T1 pulse sequence. Newer, faster sequences for T1 mapping promise whole heart coverage and improved clinical utility, but have not been validated. Multibreathhold T1 quantification with heart rate correction and single breath-hold T1 mapping using Shortened Modified Look-Locker Inversion recovery (ShMOLLI) were used in equilibrium contrast CMR to generate ECV values and compared in 3 ways.Firstly, both techniques were compared in a spectrum of disease with variable ECV expansion (n=100, 50 healthy volunteers, 12 patients with hypertrophic cardiomyopathy, 18 with severe aortic stenosis, 20 with amyloid). Secondly, both techniques were correlated to human histological collagen volume fraction (CVF%, n=18, severe aortic stenosis biopsies). Thirdly, an assessment of test:retest reproducibility of the 2 CMR techniques was performed 1 week apart in individuals with widely different ECVs (n=10 healthy volunteers, n=7 amyloid patients). More patients were able to perform ShMOLLI than the multibreath-hold technique (6% unable to breath-hold). ECV calculated by multibreath-hold T1 and ShMOLLI showed strong correlation (r(2)=0.892), little bias (bias -2.2%, 95%CI -8.9% to 4.6%) and good agreement (ICC 0.922, range 0.802 to 0.961, p<0.0001). ECV correlated with histological CVF% by multibreath-hold ECV (r(2)= 0.589) but better by ShMOLLI ECV (r(2)= 0.685). Inter-study reproducibility demonstrated that ShMOLLI ECV trended towards greater reproducibility than the multibreath-hold ECV, although this did not reach statistical significance (95%CI -4.9% to 5.4% versus 95%CI -6.4% to 7.3% respectively, p=0.21). ECV quantification by single breath-hold Sh

  3. Characterization of Benign Myocarditis Using Quantitative Delayed-Enhancement Imaging Based on Molli T1 Mapping.

    PubMed

    Toussaint, Marcel; Gilles, Raymond J; Azzabou, Noura; Marty, Benjamin; Vignaud, Alexandre; Greiser, Andreas; Carlier, Pierre G

    2015-10-01

    Delayed contrast enhancement after injection of a gadolinium-chelate (Gd-chelate) is a reference imaging method to detect myocardial tissue changes. Its localization within the thickness of the myocardial wall allows differentiating various pathological processes such as myocardial infarction (MI), inflammatory myocarditis, and cardiomyopathies. The aim of the study was first to characterize benign myocarditis using quantitative delayed-enhancement imaging and then to investigate whether the measure of the extracellular volume fraction (ECV) can be used to discriminate between MI and myocarditis.In 6 patients with acute benign myocarditis (32.2 ± 13.8 year-old, subepicardial late gadolinium enhancement [LGE]) and 18 patients with MI (52.3 ± 10.9 year-old, subendocardial/transmural LGE), myocardial T1 was determined using the Modified Look-Locker Imaging (MOLLI) sequence at 3 Tesla before and after Gd-chelate injection. T1 values were compared in LGE and normal regions of the myocardium. The myocardial T1 values were normalized to the T1 of blood, and the ECV was calculated from T1 values of myocardium and blood pre- and post-Gd injection.In both myocarditis and MI, the T1 was lower in LGE regions than in normal regions of the left ventricle. T1 of LGE areas was significantly higher in myocarditis than in MI (446.8 ± 45.8 vs 360.5 ± 66.9 ms, P = 0.003) and ECV was lower in myocarditis than in MI (34.5 ± 3.3 vs 53.8 ± 13.0 %, P = 0.004).Both inflammatory process and chronic fibrosis induce LGE (subepicardial in myocarditis and subendocardial in MI). The present study demonstrates that the determination of T1 and ECV is able to differentiate the 2 histological patterns.Further investigation will indicate whether the severity of ECV changes might help refine the predictive risk of LGE in myocarditis.

  4. Comparative analysis of fecal fat quantitation via nuclear magnetic resonance spectroscopy (1H NMR) and gravimetry.

    PubMed

    Korpi-Steiner, Nichole L; Ward, Jennie N; Kumar, Vivek; McConnell, Joseph P

    2009-02-01

    Fecal-fat is typically measured by extracting lipid from homogenized feces with subsequent gravimetric/titrimetric analyses that are time-consuming and involve toxic solvents. Accordingly, an efficient and more safe method to quantitate fecal-fat is needed. The present objective was to adapt CEM SmartTrac technology (i.e. (1)H NMR) to rapidly (< 5 min) quantitate fecal-fat and compare (1)H NMR and gravimetric performance characteristics. (1)H NMR and gravimetric measurements of stool-fat were conducted using excess stool samples (72 h collection; n=107) homogenized to semi-liquid consistency prior to analyses. The (1)H NMR method demonstrated acceptable linearity (R(2)=0.9999) and recovery (mean=105%) with imprecision (intra-assay CV=1.2-6.5%; inter-assay CV=1.8-5.8%) comparable to or better than gravimetry (intra-assay CV=1.0-17.2%; inter-assay CV=3.8-6.5%). Excellent correlation between fecal-fat quantitation by (1)H NMR and gravimetry (n=107; R(2)=0.983; y=1.0173x-0.6859) was exhibited; moreover, (1)H NMR demonstrated good sensitivity (92.3%), specificity (94.5%), negative-predictive value (92.9%) and positive-predictive value (94.1%) for malabsorption using the reference cut-off of < or = 7 g fat/24 h. These data demonstrate that (1)H NMR permits rapid and safe quantitation of fecal-fat while maintaining acceptable performance characteristics, thereby supporting the utility of (1)H NMR as an alternative method to gravimetry for fecal-fat quantitation.

  5. Capturing fast relaxing spins with SWIFT adiabatic rotating frame spin-lattice relaxation (T1ρ) mapping.

    PubMed

    Zhang, J; Nissi, M J; Idiyatullin, D; Michaeli, S; Garwood, M; Ellermann, J

    2016-04-01

    Rotating frame spin-lattice relaxation, with the characteristic time constant T1ρ, provides a means to access motion-restricted (slow) spin dynamics in MRI. As a result of their restricted motion, these spins are sometimes characterized by a short transverse relaxation time constant T2 and thus can be difficult to detect directly with conventional image acquisition techniques. Here, we introduce an approach for three-dimensional adiabatic T1ρ mapping based on a magnetization-prepared sweep imaging with Fourier transformation (MP-SWIFT) sequence, which captures signal from almost all water spin populations, including the extremely fast relaxing pool. A semi-analytical procedure for T1ρ mapping is described. Experiments on phantoms and musculoskeletal tissue specimens (tendon, articular and epiphyseal cartilages) were performed at 9.4 T for both the MP-SWIFT and fast spin echo (FSE) read outs. In the phantom with liquids having fast molecular tumbling and a single-valued T1ρ time constant, the measured T1ρ values obtained with MP-SWIFT and FSE were similar. Conversely, in normal musculoskeletal tissues, T1ρ values measured with MP-SWIFT were much shorter than the values obtained with FSE. Studies of biological tissue specimens demonstrated that T1ρ-weighted SWIFT provides higher contrast between normal and diseased tissues relative to conventional acquisitions. Adiabatic T1ρ mapping with SWIFT readout captures contributions from the otherwise undetected fast relaxing spins, allowing more informative T1ρ measurements of normal and diseased states.

  6. Pharmacokinetic behavior in sheep and cattle of 5-chloro-2-(methylthio)-6-(1-naphthyloxy)-1H-benzimidazole, a new fasciolicide agent.

    PubMed

    Ramírez, N; Mayet, L; Del Rivero, L; Ibarra-Velarde, F; Castillo, R; Hernández-Campos, A; Jung-Cook, H

    2009-04-01

    The physicochemical properties, pK(a), Log P and solubility of compound alpha, (5-chloro-2-(methylthio)-6-(1-naphthyloxy)-1H-benzimidazole), a new fasciolicide agent, were characterized using conventional methods. Also, its pharmacokinetics was evaluated in sheep and cattle. In both species an oral dose of 12 mg/kg was administered. Blood samples were collected during 144 h and analyzed by using an HPLC assay. Results showed that compound alpha is a weak base with a pK(a) value of 2.87 and log P of 1.44. The solubility was very low in aqueous solvents. Pharmacokinetic studies showed that in both species compound alpha could not be detected at any sampling time. The mean half-life (t(1/2)) values of alpha sulphoxide in sheep and cattle were 19.86 and 29.87 h, while the half-life values of alpha sulphone were 19.43 and 46.32 h respectively. C(max) values of alpha sulphoxide did not differ between species while alpha sulphone values were higher in cattle. Plasma protein binding of alpha sulphoxide was between 82% and 86%. These results, combined with the previous efficacy studies, suggest that compound alpha could be a promising fasciolicide agent.

  7. T1ρ MR Imaging of Human Musculoskeletal System

    PubMed Central

    Wang, Ligong; Regatte, Ravinder R.

    2014-01-01

    Magnetic resonance imaging (MRI) offers the direct visualization of human musculoskeletal (MSK) system, especially all diarthrodial tissues including cartilage, bone, menisci, ligaments, tendon, hip, synovium etc. Conventional MR imaging techniques based on T1- and T2-weighted, proton density (PD) contrast are inconclusive in quantifying early biochemically degenerative changes in MSK system in general and articular cartilage in particular. In recent years, quantitative MR parameter mapping techniques have been used to quantify the biochemical changes in articular cartilage with a special emphasis on evaluating joint injury, cartilage degeneration, and soft tissue repair. In this article, we will focus on cartilage biochemical composition, basic principles of T1ρ MR imaging, implementation of T1ρ pulse sequences, biochemical validation, and summarize the potential applications of T1ρ MR imaging technique in MSK diseases including osteoarthritis (OA), anterior cruciate ligament (ACL) injury, and knee joint repair. Finally, we will also review the potential advantages, challenges, and future prospects of T1ρ MR imaging for widespread clinical translation. PMID:24935818

  8. Free-breathing MOLLI: application to myocardial T(1) mapping.

    PubMed

    Tsai, Jyun-Ming; Huang, Teng-Yi; Tseng, Yu-Shen; Lin, Yi-Ru

    2012-12-01

    Of the myocardial T(1) mapping techniques, the modified Look-Locker inversion recovery (MOLLI) sequence is accurate and highly reproducible. The MOLLI sequence requires patients to hold their breath for 17 heartbeats during the scanning process to minimize respiratory motion-related artifacts. However, some patients are unable to hold their breath because of illness or limited breath-hold capacity. This study, therefore, aimed to develop a robust myocardial T(1) mapping method based on the MOLLI sequence for patients unable to perform voluntary breath-holds. This study presents a free-breathing MOLLI (FB-MOLLI) sequence and an optimized reconstruction method to allow myocardial T(1) mapping in vivo without breath-hold. Nine healthy volunteers participated in this study after providing institutionally approved consent. The FB-MOLLI sequence acquires 20 images within 29 heartbeats. The reconstruction program employs a two-step automatic image registration technique and an image selection method inspired by the self-gating cardiac imaging method. Results indicate that the proposed reconstruction method increases the accuracy and reproducibility of free-breathing T(1) measurements significantly (p < 0.001). The FB-MOLLI method provides a robust tool for clinical application in free-breathing myocardial T(1) mapping, and could greatly facilitate acquisition procedures during routine examinations.

  9. Estimating T1 from Multichannel Variable Flip Angle SPGR Sequences

    PubMed Central

    Trzasko, Joshua D.; Mostardi, Petrice M.; Riederer, Stephen J.; Manduca, Armando

    2013-01-01

    Quantitative estimation of T1 is a challenging but important task inherent to many clinical applications. The most commonly used paradigm for estimating T1 in vivo involves performing a sequence of spoiled gradient-recalled echo acquisitions at different flip angles, followed by fitting of an exponential model to the data. Although there has been substantial work comparing different fitting methods, there has been little discussion on how these methods should be applied for data acquired using multichannel receivers. In this note, we demonstrate that the manner in which multichannel data is handled can have a substantial impact on T1 estimation performance and should be considered equally as important as choice of flip angles or fitting strategy. PMID:22807160

  10. The Conformations and Structures of 1H-NONAFLUOROBUTANE

    NASA Astrophysics Data System (ADS)

    Fournier, Joseph A.; Bohn, Robert K.; Montgomery, John A.; , Jr.

    2012-06-01

    The all trans conformers of perfluorocarbons, unlike hydrocarbons, are helical with C-C-C-C dihedral angles about 1640. Fluorocarbons with H substitution can replace chlorofluorocarbons as propellants and compressor fluids without the disadvantage of causing ozone depletion in the upper atmosphere. 1H-perfluorobutane, CHF_2CF_2CF_2CF_3, has been studied by pulsed-jet Fourier transform microwave spectroscopy. The spectrum is very rich. Quantum chemical calculations identify five stable conformers with relative energies up to 1.1 kcal/mol. Thus far three conformers have been characterized and many lines remain unassigned. The assigned species have CCCCanti/CCCH gauche as well as the anti/anti and gauche/anti forms. Rotational constant values are 1428.9501(2) MHz, 593.323877(6) MHz, and 546.43578(6) MHz for the anti/gauche species, 1323.664(3) MHz, 617.6051(5) MHz for the ant/anti species, and 1066.9384(4) MHz, 768.4736(4) MHz, and 671.3145(4) MHz for the gauche/anti form.

  11. Myocardial T1 mapping: modalities and clinical applications

    PubMed Central

    Jellis, Christine L.

    2014-01-01

    Myocardial fibrosis appears to be linked to myocardial dysfunction in a multitude of non-ischemic cardiomyopathies. Accurate non-invasive quantitation of this extra-cellular matrix has the potential for widespread clinical benefit in both diagnosis and guiding therapeutic intervention. T1 mapping is a cardiac magnetic resonance (CMR) imaging technique, which shows early clinical promise particularly in the setting of diffuse fibrosis. This review will outline the evolution of T1 mapping and the various techniques available with their inherent advantages and limitations. Histological validation of this technique remains somewhat limited, however clinical application in a range of pathologies suggests strong potential for future development. PMID:24834410

  12. Vicinal 1H-1H NMR coupling constants from density functional theory as reliable tools for stereochemical analysis of highly flexible multichiral center molecules.

    PubMed

    López-Vallejo, Fabian; Fragoso-Serrano, Mabel; Suárez-Ortiz, Gloria Alejandra; Hernández-Rojas, Adriana C; Cerda-García-Rojas, Carlos M; Pereda-Miranda, Rogelio

    2011-08-05

    A protocol for stereochemical analysis, based on the systematic comparison between theoretical and experimental vicinal (1)H-(1)H NMR coupling constants, was developed and applied to a series of flexible compounds (1-8) derived from the 6-heptenyl-5,6-dihydro-2H-pyran-2-one framework. The method included a broad conformational search, followed by geometry optimization at the DFT B3LYP/DGDZVP level, calculation of the vibrational frequencies, thermochemical parameters, magnetic shielding tensors, and the total NMR spin-spin coupling constants. Three scaling factors, depending on the carbon atom hybridizations, were found for the (1)H-C-C-(1)H vicinal coupling constants: f((sp3)-(sp3)) = 0.910, f((sp3)-(sp2)) = 0.929, and f((sp2)-(sp2))= 0.977. A remarkable correlation between the theoretical (J(pre)) and experimental (1)H-(1)H NMR (J(exp)) coupling constants for spicigerolide (1), a cytotoxic natural product, and some of its synthetic stereoisomers (2-4) demonstrated the predictive value of this approach for the stereochemical assignment of highly flexible compounds containing multiple chiral centers. The stereochemistry of two natural 6-heptenyl-5,6-dihydro-2H-pyran-2-ones (14 and 15) containing diverse functional groups in the heptenyl side chain was also analyzed by application of this combined theoretical and experimental approach, confirming its reliability. Additionally, a geometrical analysis for the conformations of 1-8 revealed that weak hydrogen bonds substantially guide the conformational behavior of the tetraacyloxy-6-heptenyl-2H-pyran-2-ones.

  13. Quantitative evaluation of ischemic myocardial scar tissue by unenhanced T1 mapping using 3.0 Tesla MR scanner.

    PubMed

    Okur, Aylin; Kantarcı, Mecit; Kızrak, Yeşim; Yıldız, Sema; Pirimoğlu, Berhan; Karaca, Leyla; Oğul, Hayri; Sevimli, Serdar

    2014-01-01

    We aimed to use a noninvasive method for quantifying T1 values of chronic myocardial infarction scar by cardiac magnetic resonance imaging (MRI), and determine its diagnostic performance. We performed cardiac MRI on 29 consecutive patients with known coronary artery disease (CAD) on 3.0 Tesla MRI scanner. An unenhanced T1 mapping technique was used to calculate T1 relaxation time of myocardial scar tissue, and its diagnostic performance was evaluated. Chronic scar tissue was identified by delayed contrast-enhancement (DE) MRI and T2-weighted images. Sensitivity, specificity, and accuracy values were calculated for T1 mapping using DE images as the gold standard. Four hundred and forty-two segments were analyzed in 26 patients. While myocardial chronic scar was demonstrated in 45 segments on DE images, T1 mapping MRI showed a chronic scar area in 54 segments. T1 relaxation time was higher in chronic scar tissue, compared with remote areas (1314±98 ms vs. 1099±90 ms, P < 0.001). Therefore, increased T1 values were shown in areas of myocardium colocalized with areas of DE and normal signal on T2-weighted images. There was a significant correlation between T1 mapping and DE images in evaluation of myocardial wall injury extent (P < 0.05). We calculated sensitivity, specificity, and accuracy as 95.5%, 97%, and 96%, respectively. The results of the present study reveal that T1 mapping MRI combined with T2-weighted images might be a feasible imaging modality for detecting chronic myocardial infarction scar tissue.

  14. Hexamethyldisiloxane-based nanoprobes for (1) H MRI oximetry.

    PubMed

    Gulaka, Praveen K; Rastogi, Ujjawal; McKay, Madalyn A; Wang, Xianghui; Mason, Ralph P; Kodibagkar, Vikram D

    2011-12-01

    Quantitative in vivo oximetry has been reported using (19) F MRI in conjunction with reporter molecules, such as perfluorocarbons, for tissue oxygenation (pO(2) ). Recently, hexamethyldisiloxane (HMDSO) has been proposed as a promising alternative reporter molecule for (1) H MRI-based measurement of pO(2) . To aid biocompatibility for potential systemic administration, we prepared various nanoemulsion formulations using a wide range of HMDSO volume fractions and HMDSO to surfactant ratios. Calibration curves (R(1) versus pO(2) ) for all emulsion formulations were found to be linear and similar to neat HMDSO for low surfactant concentrations (<10% v/v). A small temperature dependence in the calibration curves was observed, similar to previous reports on neat HMDSO, and was characterized to be approximately 1 Torr/ °C under hypoxic conditions. To demonstrate application in vivo, 100 µL of this nanoemulsion was administered to healthy rat thigh muscle (Fisher 344, n=6). Dynamic changes in mean thigh tissue pO(2) were measured using the PISTOL (proton imaging of siloxanes to map tissue oxygenation levels) technique in response to oxygen challenge. Changing the inhaled gas to oxygen for 30 min increased the mean pO(2) significantly (p<0.001) from 39 ± 7 to 275 ± 27 Torr. When the breathing gas was switched back to air, the tissue pO(2) decreased to a mean value of 45 ± 6 Torr, not significantly different from baseline (p>0.05), in 25 min. A first-order exponential fit to this part of the pO(2) data (i.e. after oxygen challenge) yielded an oxygen consumption-related kinetic parameter k=0.21 ± 0.04 min(-1) . These results demonstrate the feasibility of using HMDSO nanoemulsions as nanoprobes of pO(2) and their utility to assess oxygen dynamics in vivo, further developing quantitative (1) H MRI oximetry.

  15. (1)H NMR metabonomic analysis in renal cell carcinoma: a possible diagnostic tool.

    PubMed

    Zira, Athina N; Theocharis, Stamatios E; Mitropoulos, Dionisios; Migdalis, Vasilios; Mikros, Emmanuel

    2010-08-06

    (1)H NMR based metabonomic approach was applied in order to monitor the alterations of plasma metabolic profile in Renal Cell Carcinoma (RCC) patients and controls. (1)H NMR spectra of plasma samples from 32 RCC patients and 13 controls (patients exhibiting benign urologic disease) were recorded and analyzed using multivariate statistical techniques. Alterations in the levels of LDL/VLDL, NAC, lactate, and choline were observed between RCC patients and controls discriminating these groups in Principal Component Analysis (PCA) plots. Post OSC PLS-DA presented a satisfactory clustering between T1 with T3 RCC patients. Decrease in plasma lipid concentrations in RCC patients was verified using conventional clinical chemistry analysis. The results suggest that combination of (1)H NMR spectroscopy with PCA has potential in cancer diagnosis; however, a limitation of the method to monitor RCC is that major biomarkers revealed (lipoproteins and choline) in this metabolic profile are not unique to RCC but may be the result of the presence of any malignancy.

  16. T1ρ Imaging in Premanifest Huntington Disease Reveals Changes Associated with Disease Progression

    PubMed Central

    Wassef, Shafik N.; Wemmie, John; Johnson, Casey P.; Johnson, Hans; Paulsen, Jane S.; Long, Jeffrey D.; Magnotta, Vincent A.

    2016-01-01

    Background Imaging biomarkers sensitive to Huntington’s disease (HD) during the premanifest phase preceding motor diagnosis may accelerate identification and evaluation of potential therapies. For this purpose, quantitative MRI sensitive to tissue microstructure and metabolism may hold great potential. We investigated the potential value of T1ρ relaxation to detect pathological changes in premanifest HD (preHD) relative to other quantitative relaxation parameters. Methods Quantitative MR parametric mapping was used to assess differences between 50 preHD subjects and 26 age- and sex-matched controls. Subjects with preHD were classified into two progression groups based on their CAG-age product (CAP) score; a high and a low/moderate CAP group. Voxel-wise and region-of-interest analyses were used to assess changes in the quantitative relaxation times. Results T1ρ showed a significant increase in the relaxation times in the high-CAP group, as compared to controls, largely in the striatum. The T1ρ changes in the preHD subjects showed a significant relationship with CAP score. No significant changes in T2 or T2* relaxation times were found in the striatum. T2* relaxation changes were found in the globus pallidus, but no significant changes with disease progression were found. Conclusion These data suggest that quantitative T1ρ mapping may provide a useful marker for assessing disease progression in HD. The absence of T2 changes suggests that the T1ρ abnormalities are unlikely owing to altered water content or tissue structure. The established sensitivity of T1ρ to pH and glucose suggests that these factors are altered in HD perhaps owing to abnormal mitochondrial function. PMID:25820773

  17. A novel enterocin T1 with anti-Pseudomonas activity produced by Enterococcus faecium T1 from Chinese Tibet cheese.

    PubMed

    Liu, Hui; Zhang, Lanwei; Yi, Huaxi; Han, Xue; Gao, Wei; Chi, Chunliang; Song, Wei; Li, Haiying; Liu, Chunguang

    2016-02-01

    An enterocin-producing Enterococcus faecium T1 was isolated from Chinese Tibet cheese. The enterocin was purified by SP-Sepharose and reversed phase HPLC. It was identified as unique from other reported bacteriocins based on molecular weight (4629 Da) and amino acid compositions; therefore it was subsequently named enterocin T1. Enterocin T1 was stable at 80-100 °C and over a wide pH range, pH 3.0-10.0. Protease sensitivity was observed to trypsin, pepsin, papain, proteinase K, and pronase E. Importantly, enterocin T1 was observed to inhibit the growth of numerous Gram-negative and Gram-positive bacteria including Pseudomonas putida, Pseudomonas aeruginosa, Pseudomonas fluorescens, Escherichia coli, Salmonella typhimurium, Shigella flexneri, Shigella sonnei, Staphylococcus aureus, Listeria monocytogenes. Take together, these results suggest that enterocin T1 is a novel bacteriocin with the potential to be used as a bio-preservative to control Pseudomonas spp. in food.

  18. Fast T1 mapping of the brain at high field using Look-Locker and fast imaging.

    PubMed

    Jiang, Ke; Zhu, Yanjie; Jia, Sen; Wu, Yin; Liu, Xin; Chung, Yiu-Cho

    2017-02-01

    This study aims to develop and evaluate a new method for fast high resolution T1 mapping of the brain based on the Look-Locker technique. Single-shot turboflash sequence with high temporal acceleration is used to sample the recovery of inverted magnetization. Multi-slice interleaved acquisition within one inversion slab is used to reduce the number of inversion pulses and hence SAR. Accuracy of the proposed method was studied using simulation and validated in phantoms. It was then evaluated in healthy volunteers and stroke patients. In-vivo results were compared to values obtained by inversion recovery fast spin echo (IR-FSE) and literatures. With the new method, T1 values in phantom experiments agreed with reference values with median error <3%. For in-vivo experiments, a T1 map was acquired in 3.35s and the T1 maps of the whole brain were acquired in 2min with two-slice interleaving, with a spatial resolution of 1.1×1.1×4mm(3). The T1 values obtained were comparable to those measured with IR-FSE and those reported in literatures. These results demonstrated the feasibility of the proposed method for fast T1 mapping of the brain in both healthy volunteers and stroke patients at 3T.

  19. Differential protonation and dynamic structure of doxylamine succinate in solution using 1H and 13C NMR.

    PubMed

    Somashekar, B S; Nagana Gowda, G A; Ramesha, A R; Khetrapal, C L

    2004-07-01

    A protonation and dynamic structural study of doxylamine succinate, a 1:1 salt of succinic acid with dimethyl-[2-(1-phenyl-1-pyridin-2-yl-ethoxy)ethyl]amine, in solution using one- and two-dimensional 1H and 13C NMR experiments at variable temperature and concentration is presented. The two acidic protons of the salt doxylamine succinate are in 'intermediate' exchange at room temperature, as evidenced by the appearance of a broad signal. This signal evolves into two distinct signals below about -30 degrees C. A two-dimensional 1H-1H double quantum filtered correlation experiment carried out at -55 degrees C shows protonation of one of the acidic protons to the dimethylamine nitrogen. A two-dimensional rotating frame 1H-1H NOE experiment at the same temperature reveals that the other proton remains with the succinate moiety. Comparison of the 1H and 13C chemical shifts and the 13C T1 relaxation times of the salt with those of the free base further substantiate the findings.

  20. Evaluation for Standardization of (1)H Quantitative Nuclear Magnetic Resonance Spectroscopy by Round Robin Test.

    PubMed

    Miura, Toru; Sugimoto, Naoki; Watanabe, Ryuichi; Suematsu, Takako; Takayanagi, Yoichiro; Ito, Yoshinobu; Saito, Naoki; Sawa, Ryuichi; Kato, Tsuyoshi; Fujimine, Yoshinori; Koike, Ryo; Ohfuku, Yuko; Yamada, Yuko; Utsumi, Hiroaki; Suzuki, Toshiyuki

    2017-09-29

      (1)H quantitative Nuclear Magnetic Resonance ((1)H qNMR) is known as a powerful tool for determination of analytes without the need for their identical standards, which is eligible to a primary rate method. (1)H qNMR has been already stipulated to an assay for purity determination in Japanese Pharmacopoeia (JP), and then this technique has been also applied in several fields such as pharmaceutical and food sciences. However, there is little information about the accuracy of (1)H qNMR so that the further applications into other fields such as industrial chemistry could be constricted. In this study, in order to assess the reliability of (1)H qNMR, we designed the round-robin test of (1)H qNMR under the basis of the measurement conditions described in JP. 1,4-Bis(trimethylsilyl)benzene-d4 (1,4-BTMSB-d4, 99.9 %± 0.6 % w/w) and 3,5-Bis(trifluoromethyl)benzoic acid (3,5-BTMFBA, 99.96 %±0.06 % w/w), which are certified reference materials (CRMs), were adopted to analyte and qNMR reference standard respectively for the accurate evaluation in this test. Six NMR instruments in 5 institutions optimized to (1)H qNMR conditions provided the purity 1,4-BTMSB-d4 within acceptable error range. This result represented that (1)H qNMR has the capability to determine precisely the value of analyte in practical analytical field and to be set as official analytical method for purity determination or assay of concentration of organic compounds.

  1. Metabolomic by 1H NMR spectroscopy differentiates "Fiano di Avellino" white wines obtained with different yeast strains.

    PubMed

    Mazzei, Pierluigi; Spaccini, Riccardo; Francesca, Nicola; Moschetti, Giancarlo; Piccolo, Alessandro

    2013-11-13

    We employed (1)H NMR spectroscopy to examine the molecular profile of a white "Fiano di Avellino" wine obtained through fermentation by either a commercial or a selected autochthonous Saccharomyces cerevisiae yeast starter. The latter was isolated from the same grape variety used in the wine-making process in order to strengthen the relationship between wine molecular quality and its geographical origin. (1)H NMR spectra, where water and ethanol signals were suppressed by a presaturated T1-edited NMR pulse sequence, allowed for definition of the metabolic content of the two differently treated wines. Elaboration of NMR spectral data by multivariate statistical analyses showed that the two different yeasts led to significant diversity in the wine metabolomes. Our results indicate that metabolomics by (1)H NMR spectroscopy combined with multivariate statistical analysis enables wine differentiation as a function of yeast species and other wine-making factors, thereby contributing to objectively relate wine quality to the terroir.

  2. Transfer of hyperpolarization from long T 1 storage nuclei to short T 1 neighbors using FLOPSY-8

    NASA Astrophysics Data System (ADS)

    Moreno, Karlos X.; Harrison, Crystal; Dean Sherry, A.; Malloy, Craig R.; Merritt, Matthew E.

    2011-12-01

    Nuclei with long T 1s are optimal targets for dynamic nuclear polarization (DNP). Therefore, most of the agents used in metabolic imaging and spectroscopy studies are based on carboxylic acid moieties that lack protons, a strong source of dipolar relaxation. Metabolic flux information encoded into spectra of small molecule metabolites in the form of the 13C isotopomer data cannot be accessed using standard 13C hyperpolarization methods because protonated carbons relax too quickly through T 1 dipolar relaxation. It is shown here that the longitudinal mixing sequence FLOPSY-8 can be used to transfer polarization from a long T 1 storage nucleus to adjacent protonated carbons so that they may be detected with high sensitivity. We demonstrate that FLOPSY-8 allows a direct readout of isotopomer populations in butyrate and glutamate in vitro.

  3. Can Native T1 Mapping Differentiate between Healthy and Diffuse Diseased Myocardium in Clinical Routine Cardiac MR Imaging?

    PubMed Central

    Goebel, Juliane; Seifert, Ingmar; Nensa, Felix; Schemuth, Haemi P.; Maderwald, Stefan; Quick, Harald H.; Schlosser, Thomas; Jensen, Christoph; Bruder, Oliver; Nassenstein, Kai

    2016-01-01

    Objectives T1 mapping allows quantitative myocardial assessment, but its value in clinical routine remains unclear. We investigated, whether the average native myocardial T1 value can be used as a diagnostic classifier between healthy and diffuse diseased myocardium. Methods Native T1 mapping was performed in 54 persons with healthy hearts and in 150 patients with diffuse myocardial pathologies (coronary artery disease (CAD): n = 76, acute myocarditis: n = 19, convalescent myocarditis: n = 26, hypertrophic cardiomyopathy (HCM): n = 12, dilated cardiomyopathy (DCM): n = 17) at 1.5 Tesla in a mid-ventricular short axis slice using a modified Look-Locker inversion recovery (MOLLI) sequence. The average native myocardial T1 value was measured using dedicated software for each patient. The mean as well as the range of the observed average T1 values were calculated for each group, and compared using t-test. The ability of T1 mapping to differentiate between healthy and diffuse diseased myocardium was assessed using receiver operating characteristic analysis (ROC). Results The mean T1 value of the group “healthy hearts” (955±34ms) differed significantly from that of the groups DCM (992±37ms, p<0.001), HCM (980±44ms, p = 0.035), and acute myocarditis (974±36ms, p = 0.044). No significant difference was observed between the groups “healthy hearts” and CAD (951±37ms, p = 0.453) or convalescent myocarditis (965±40ms, p = 0.240). The average native T1 value varied considerably within all groups (range: healthy hearts, 838-1018ms; DCM, 882-1034ms; HCM, 897-1043ms; acute myocarditis, 925-1025ms; CAD, 867-1082ms; convalescent myocarditis, 890-1071ms) and overlapped broadly between all groups. ROC analysis showed, that the average native T1 value does not allow for differentiating between healthy and diffuse diseased myocardium, except for the subgroup of DCM. Conclusions The average native T1 value in cardiac MR imaging does not allow differentiating between healthy

  4. T2 can be greater than 2T1

    NASA Astrophysics Data System (ADS)

    Sevian, H. M.; Skinner, J. L.

    1989-08-01

    We consider a quantum-mechanical two-level system under the influence of both diagonal and off-diagonal stochastic perturbations, and focus on the decay times T1 and T2, which refer to the relaxation to equilibrium of the populations and relative phase of the two levels, respectively. From both theoretical and experimental viewpoints one traditionally expects that T2≤2T1. On the other hand, from a fourth-order cumulant expansion calculation of the asymptotic time dependence of the density matrix elements, Budimir and Skinner [J. Stat. Phys. 49, 1029 (1987)] showed that, in fact, in some instances T2>2T1. In this paper we solve the stochastic model numerically, which leads to the exact time dependence of the density matrix at all times. We find that the analytic prediction that T2>2T1 is not only correct, but also meaningful, in the sense that the density matrix elements decay exponentially after only a short transient time.

  5. New superconducting ternary molybdenum chalcogenides InMo6Se8,T1Mo6S8, and T1Mo6Se8

    NASA Astrophysics Data System (ADS)

    Tarascon, J. M.; Disalvo, F. J.; Murphy, D. W.; Hull, G.; Waszczak, J. V.

    1984-01-01

    We present the synthesis and the physical properties of new ternary molybdenum chalcogenides MMo6X8 (M=In, T1;X=S, Se) that cannot be made by the usual high-temperature techniques (except for InMo6S8). These materials were obtained by diffusion of the ternary element into the binary phase Mo6X8 at a relatively low temperature (430°C and 520°C for the sulfides and selenides, respectively). They crystallize in the rhombohedral space group R3 (C43) with (ar=6.78 Å, αr=89.86°) when M=In and X=Se and with (ar=6.57 Å, αr=88.45°) and (ar=6.836 Å, αr=88.35°) when M=T1 and X=S and Se, respectively. T1Mo6Se8 presents a large temperature-dependent paramagnetism and begins superconducting at 12.2 K, the highest value ever observed in the selenide Chevrel phases, while that of T1Mo6S8 is lower, 8.7 K. The susceptibility of InMo6Se8 reveals the existence of two first-order transitions that have considerable hysteresis, while only one transition without hysteresis is observed for InMo6S8. The absence of superconductivity down to 1.5 K has been confirmed for this last compound, while the homolog selenide begins superconducting at 8.2 K.

  6. p53 expression predicts progression and poor survival in T1 bladder tumours.

    PubMed

    Llopis, J; Alcaraz, A; Ribal, M J; Solé, M; Ventura, P J; Barranco, M A; Rodriguez, A; Corral, J M; Carretero, P

    2000-06-01

    Histological grade (G) is the only parameter proved to have prognostic value for progression in T1 transitional cell carcinoma (TCC) of the bladder, although it is considered inaccurate to make clinical decisions on individuals. The aim of the present study was to evaluate the prognostic relevance of p53 expression in T1 TCC of the bladder. Clinical records of 207 patients with T1 TCC of the bladder were reviewed for clinical parameters reported to influence the evolution of superficial bladder cancer. Among these 207 patients, 40 developed muscle-invasive disease (20 G2 and 20 G3). A retrospective case-control study was then carried out comparing the latter 40 tumours with 40 control tumours matched by grade, sex, age, number and size of the tumours, chemical exposure and presence of carcinoma in situ. p53 immunostaining with monoclonal antibody was performed in these two groups. Histological grade was the only clinical parameter that influenced evolution. p53 expression correlated with tumour progression, since it was observed in 21 out of 24 p53-positive tumours and in only 20 of 56 p53-negative tumours (p<0.0001), showing a specificity of 93. 5% and a sensitivity of 53%. p53 expression correlated as well with patient survival, being 39% in patients with p53-positive tumours and 80% in patients with p53-negative tumours at 60 months (p<0. 0001). p53 protein expression has prognostic value for survival and progression in T1 bladder tumours and can be used for early detection of poor-prognosis T1 bladder tumours.

  7. Teaching 1H NMR Spectrometry Using Computer Modeling.

    ERIC Educational Resources Information Center

    Habata, Yoichi; Akabori, Sadatoshi

    2001-01-01

    Molecular modeling by computer is used to display stereochemistry, molecular orbitals, structure of transition states, and progress of reactions. Describes new ideas for teaching 1H NMR spectroscopy using computer modeling. (Contains 12 references.) (ASK)

  8. Meniscal Measurements of T1ρ and T2 at MR Imaging in Healthy Subjects and Patients with Osteoarthritis

    PubMed Central

    Rauscher, Isabel; Stahl, Robert; Cheng, Jonathan; Li, Xiaojuan; Huber, Markus B.; Luke, Anthony; Majumdar, Sharmila; Link, Thomas M.

    2008-01-01

    Purpose: To prospectively evaluate differences in T1ρ (T1 relaxation time in the rotating frame) and T2 values in the meniscus at magnetic resonance (MR) imaging in both patients with varying degrees of osteoarthritis (OA) and healthy control subjects. Materials and Methods: The study was institutional review board approved and HIPAA compliant. Written informed consent was obtained from all subjects. T1ρ and T2 measurements were performed at 3.0-T MR imaging in 60 subjects deemed to be healthy (n = 23; mean age, 34.1 years ± 10.0 [standard deviation]; age range, 23–59 years), having mild OA (n = 27; mean age, 52.5 years ± 10.9; age range, 32–69 years), or having severe OA (n = 10; mean age, 61.6 years ± 11.6; age range, 50–86 years). Semiautomatic segmentation was performed to generate T1ρ and T2 maps of the menisci. Clinical findings were assessed by using Western Ontario and McMaster Osteoarthritis (WOMAC) questionnaires. Differences in T1ρ and T2 values between the three subject groups were calculated by using two-tailed t tests (with P < .05 indicating significance), and receiver operating characteristic analyses were performed. Correlations of meniscal T1ρ and T2 values with age, cartilage-derived T1ρ and T2 parameters, and WOMAC scores were calculated. Results: Significant differences between the three subject groups were found: Mean T1ρ values were 14.7 msec ± 5.5, 16.1 msec ± 6.6, and 19.3 msec ± 7.6 for the healthy, mild OA, and severe OA groups, respectively. Mean T2 values were 11.4 msec ± 3.9, 13.5 msec ± 4.7, and 16.6 msec ± 8.2 for the healthy, mild OA, and severe OA groups, respectively. Correlations of meniscal T1ρ and T2 values with subject age (R2 = 0.18, for correlation with T2 only), cartilage-derived parameters (R2 = 0.14–0.29), and WOMAC scores (R2 = 0.11–0.45) were significant. Conclusion: Meniscal T1ρ and T2 values correlate with clinical findings of OA and can be used to differentiate healthy subjects from

  9. Modified look-locker inversion recovery T1 mapping indices: assessment of accuracy and reproducibility between magnetic resonance scanners

    PubMed Central

    2013-01-01

    Background Cardiovascular magnetic resonance (CMR) T1 mapping indices, such as T1 time and partition coefficient (λ), have shown potential to assess diffuse myocardial fibrosis. The purpose of this study was to investigate how scanner and field strength variation affect the accuracy and precision/reproducibility of T1 mapping indices. Methods CMR studies were performed on two 1.5T and three 3T scanners. Eight phantoms were made to mimic the T1/T2 of pre- and post-contrast myocardium and blood at 1.5T and 3T. T1 mapping using MOLLI was performed with simulated heart rate of 40-100 bpm. Inversion recovery spin echo (IR-SE) was the reference standard for T1 determination. Accuracy was defined as the percent error between MOLLI and IR-SE, and scan/re-scan reproducibility was defined as the relative percent mean difference between repeat MOLLI scans. Partition coefficient was estimated by ΔR1myocardium phantom/ΔR1blood phantom. Generalized linear mixed model was used to compare the accuracy and precision/reproducibility of T1 and λ across field strength, scanners, and protocols. Results Field strength significantly affected MOLLI T1 accuracy (6.3% error for 1.5T vs. 10.8% error for 3T, p<0.001) but not λ accuracy (8.8% error for 1.5T vs. 8.0% error for 3T, p=0.11). Partition coefficients of MOLLI were not different between two 1.5T scanners (47.2% vs. 47.9%, p=0.13), and showed only slight variation across three 3T scanners (49.2% vs. 49.8% vs. 49.9%, p=0.016). Partition coefficient also had significantly lower percent error for precision (better scan/re-scan reproducibility) than measurement of individual T1 values (3.6% for λ vs. 4.3%-4.8% for T1 values, approximately, for pre/post blood and myocardium values). Conclusion Based on phantom studies, T1 errors using MOLLI ranged from 6-14% across various MR scanners while errors for partition coefficient were less (6-10%). Compared with absolute T1 times, partition coefficient showed less variability across

  10. Motion Correction for Myocardial T1 Mapping using Image Registration with Synthetic Image Estimation

    PubMed Central

    Xue, Hui; Shah, Saurabh; Greiser, Andreas; Guetter, Christoph; Littmann, Arne; Jolly, Marie-Pierre; Arai, Andrew E; Zuehlsdorff, Sven; Guehring, Jens; Kellman, Peter

    2013-01-01

    Quantification of myocardial T1 relaxation has potential value in the diagnosis of both ischemic and non-ischemic cardiomyopathies. Image acquisition using the Modified Look-Locker Inversion Recovery technique is clinically feasible for T1 mapping. However, respiratory motion limits its applicability and degrades the accuracy of T1 estimation. The robust registration of acquired inversion recovery images is particularly challenging due to the large changes in image contrast, especially for those images acquired near the signal null point of the inversion recovery and other inversion times for which there is little tissue contrast. In this paper, we propose a novel motion correction algorithm. This approach is based on estimating synthetic images presenting contrast changes similar to the acquired images. The estimation of synthetic images is formulated as a variational energy minimization problem. Validation on a consecutive patient data cohort shows that this strategy can perform robust non-rigid registration to align inversion recovery images experiencing significant motion and lead to suppression of motion induced artifacts in the T1 map. PMID:22135227

  11. Conformation Analysis of T1 Lipase on Alcohols Solvent using Molecular Dynamics Simulation

    NASA Astrophysics Data System (ADS)

    Putri, A. M.; Sumaryada, T.; Wahyudi, S. T.

    2017-07-01

    Biodiesel usually is produced commercially via a transesterification reaction of vegetable oil with alcohol and alkali catalyst. The alkali catalyst has some drawbacks, such as the soap formation during the reaction. T1 Lipase enzyme had been known as a thermostable biocatalyst which is able to produce biodiesel through a cleaner process. In this paper the performance of T1 lipase enzyme as catalyst for transesterification reaction in pure ethanol, methanol, and water solvents were studied using a Molecular Dynamics (MD) Simulation at temperature of 300 K for 10 nanoseconds. The results have shown that in general the conformation of T1 lipase enzyme in methanol is more dynamics as shown by the value of root mean square deviation (RMSD), root mean squared fluctuation (RMSF), and radius of gyration. The highest solvent accessible surface area (SASA) total was also found in methanol due to the contribution of non-polar amino acid in the interior of the protein. Analysis of MD simulation has also revealed that the enzyme structure tend to be more rigid in ethanol environment. The analysis of electrostatic interactions have shown that Glu359-Arg270 salt-bridge pair might hold the key of thermostability of T1 lipase enzyme as shown by its strong and stable binding in all three solvents.

  12. Neutralization of acidic drainage by Cryptococcus sp. T1 immobilized in alginate beads.

    PubMed

    Okai, Masahiko; Suwa, Chisato; Nagaoka, Shintaro; Obara, Nobuo; Mitsuya, Daisuke; Kurihara, Ayako; Ishida, Masami; Urano, Naoto

    2017-09-15

    We isolated Cryptococcus sp. T1 from Lake Tazawa's acidic water in Japan. Cryptococcus sp. T1 neutralized an acidic casamino acid solution (pH 3.0) and released ammonia from the casamino acids to aid the neutralization. The neutralization volume was estimated to be approximately 0.4 mL/h. The casamino acids' amino acids decreased (1.24→0.15 mM); ammonia increased (0.22→0.99 mM). We neutralized acidic drainage water (1 L) from a Tamagawa River neutralization plant, which was run through the column with the T1-immobilized alginate beads at a flow rate of 0.5 mL/min, and observed that the viscosity, particle size and amounts of the alginate beads affected the acidic drainage neutralization with an increase of the pH value from 5.26 to 6.61 in the last fraction. An increase in the Al concentration decreased Cryptococcus sp. T1's neutralization ability. After 48 h, the pH of acidic water with 50 mg/L Al was apparently lower than that without Al. Almost no pH increase was observed at 75 mg/L.

  13. Genetic instability promotes the acquisition of chromosomal imbalances in T1b and T1c breast adenocarcinomas.

    PubMed

    Blegen, H; Ghadimi, B M; Jauho, A; Zetterberg, A; Eriksson, E; Auer, G; Ried, T

    2001-01-01

    In order to evaluate biological and genetic properties of early breast carcinomas we analyzed microdissected tissue from 33 primary breast carcinomas stage T1b and T1c with respect to the nuclear DNA content, the expression pattern of Ki-67, cyclin A, p27KIP1, p53 and p21WAF1, and chromosomal gains and losses. The results show that T1b carcinomas (6-10 mm, n=17) were frequently near-diploid (53%) with low proliferative activity and staining patterns of p53 and p21WAF1 that suggest the presence of wild type protein. The majority (12/16) of the T1c tumors (11-20 mm), however, was aneuploid, and proliferative activity and p53 expression were increased. Larger tumor size correlated with an increasing number of chromosomal copy number changes and in particular with regional amplifications. High level copy number increases (amplifications), however, were found exclusively in the aneuploid tumors. Amplification events correlated with elevated cyclin A and reduced p27 expression, respectively. Our results suggest that the sequential acquisition of genomic imbalances during tumor progression is accelerated in aneuploid tumors, and may contribute to the increased malignancy potential.

  14. Genetic Instability Promotes the Acquisition of Chromosomal Imbalances in T1b and T1c Breast Adenocarcinomas

    PubMed Central

    Blegen, Harald; Ghadimi, B. Michael; Jauho, Annukka; Zetterberg, Anders; Eriksson, Elina; Auer, Gert; Ried, Thomas

    2001-01-01

    In order to evaluate biological and genetic properties of early breast carcinomas we analyzed microdissected tissue from 33 primary breast carcinomas stage T1b and T1c with respect to the nuclear DNA content, the expression pattern of Ki‐67, cyclin A, p27KIP1, p53 and p21WAF1, and chromosomal gains and losses. The results show that T1b carcinomas (6–10 mm, n=17) were frequently near‐diploid (53%) with low proliferative activity and staining patterns of p53 and p21WAF1 that suggest the presence of wild type protein. The majority (12/16) of the T1c tumors (11–20 mm), however, was aneuploid, and proliferative activity and p53 expression were increased. Larger tumor size correlated with an increasing number of chromosomal copy number changes and in particular with regional amplifications. High level copy number increases (amplifications), however, were found exclusively in the aneuploid tumors. Amplification events correlated with elevated cyclin A and reduced p27 expression, respectively. Our results suggest that the sequential acquisition of genomic imbalances during tumor progression is accelerated in aneuploid tumors, and may contribute to the increased malignancy potential. PMID:11455031

  15. Functionally active t1-t1 interfaces revealed by the accessibility of intracellular thiolate groups in kv4 channels.

    PubMed

    Wang, Guangyu; Shahidullah, Mohammad; Rocha, Carmen A; Strang, Candace; Pfaffinger, Paul J; Covarrubias, Manuel

    2005-07-01

    Gating of voltage-dependent K(+) channels involves movements of membrane-spanning regions that control the opening of the pore. Much less is known, however, about the contributions of large intracellular channel domains to the conformational changes that underlie gating. Here, we investigated the functional role of intracellular regions in Kv4 channels by probing relevant cysteines with thiol-specific reagents. We find that reagent application to the intracellular side of inside-out patches results in time-dependent irreversible inhibition of Kv4.1 and Kv4.3 currents. In the absence or presence of Kv4-specific auxiliary subunits, mutational and electrophysiological analyses showed that none of the 14 intracellular cysteines is essential for channel gating. C110, C131, and C132 in the intersubunit interface of the tetramerization domain (T1) are targets responsible for the irreversible inhibition by a methanethiosulfonate derivative (MTSET). This result is surprising because structural studies of Kv4-T1 crystals predicted protection of the targeted thiolate groups by constitutive high-affinity Zn(2+) coordination. Also, added Zn(2+) or a potent Zn(2+) chelator (TPEN) does not significantly modulate the accessibility of MTSET to C110, C131, or C132; and furthermore, when the three critical cysteines remained as possible targets, the MTSET modification rate of the activated state is approximately 200-fold faster than that of the resting state. Biochemical experiments confirmed the chemical modification of the intact alpha-subunit and the purified tetrameric T1 domain by MTS reagents. These results conclusively demonstrate that the T1--T1 interface of Kv4 channels is functionally active and dynamic, and that critical reactive thiolate groups in this interface may not be protected by Zn(2+) binding.

  16. Functionally Active T1-T1 Interfaces Revealed by the Accessibility of Intracellular Thiolate Groups in Kv4 Channels

    PubMed Central

    Wang, Guangyu; Shahidullah, Mohammad; Rocha, Carmen A.; Strang, Candace; Pfaffinger, Paul J.; Covarrubias, Manuel

    2005-01-01

    Gating of voltage-dependent K+ channels involves movements of membrane-spanning regions that control the opening of the pore. Much less is known, however, about the contributions of large intracellular channel domains to the conformational changes that underlie gating. Here, we investigated the functional role of intracellular regions in Kv4 channels by probing relevant cysteines with thiol-specific reagents. We find that reagent application to the intracellular side of inside-out patches results in time-dependent irreversible inhibition of Kv4.1 and Kv4.3 currents. In the absence or presence of Kv4-specific auxiliary subunits, mutational and electrophysiological analyses showed that none of the 14 intracellular cysteines is essential for channel gating. C110, C131, and C132 in the intersubunit interface of the tetramerization domain (T1) are targets responsible for the irreversible inhibition by a methanethiosulfonate derivative (MTSET). This result is surprising because structural studies of Kv4-T1 crystals predicted protection of the targeted thiolate groups by constitutive high-affinity Zn2+ coordination. Also, added Zn2+ or a potent Zn2+ chelator (TPEN) does not significantly modulate the accessibility of MTSET to C110, C131, or C132; and furthermore, when the three critical cysteines remained as possible targets, the MTSET modification rate of the activated state is ∼200-fold faster than that of the resting state. Biochemical experiments confirmed the chemical modification of the intact α-subunit and the purified tetrameric T1 domain by MTS reagents. These results conclusively demonstrate that the T1T1 interface of Kv4 channels is functionally active and dynamic, and that critical reactive thiolate groups in this interface may not be protected by Zn2+ binding. PMID:15955876

  17. Untangle soil-water-mucilage interactions: 1H NMR Relaxometry is lifting the veil

    NASA Astrophysics Data System (ADS)

    Brax, Mathilde; Buchmann, Christian; Schaumann, Gabriele Ellen

    2017-04-01

    Mucilage is mainly produced at the root tips and has a high water holding capacity derived from highly hydrophilic gel-forming substances. The objective of the MUCILAGE project is to understand the mechanistic role of mucilage for the regulation of water supply for plants. Our subproject investigates the chemical and physical properties of mucilage as pure gel and mixed with soil. 1H-NMR Relaxometry and PFG NMR represent non-intrusive powerful methods for soil scientific research by allowing quantification of the water distribution as well as monitoring of the water mobility in soil pores and gel phases.Relaxation of gel water differs from the one of pure water due to additional interactions with the gel matrix. Mucilage in soil leads to a hierarchical pore structure, consisting of the polymeric biohydrogel network surrounded by the surface of soil particles. The two types of relaxation rates 1/T1 and 1/T2 measured with 1H-NMR relaxometry refer to different relaxation mechanisms of water, while PFG-NMR measures the water self-diffusion coefficient. The objective of our study is to distinguish in situ water in gel from pore water in a simplified soil system, and to determine how the "gel effect" affects both relaxation rates and the water self-diffusion coefficient in porous systems. We demonstrate how the mucilage concentration and the soil solution alter the properties of water in the respective gel phases and pore systems in model soils. To distinguish gel-inherent processes from classical processes, we investigated the variations of the water mobility in pure chia mucilage under different conditions by using 1H-NMR relaxometry and PFG NMR. Using model soils, the signals coming from pore water and gel water were differentiated. We combined the equations describing 1H-NMR relaxation in porous systems and our experimental results, to explain how the presence of gel in soil affects 1H-NMR relaxation. Out of this knowledge we propose a method, which determines in

  18. T1rho MRI of Menisci in Patients with Osteoarthritis at 3T: A Preliminary Study

    PubMed Central

    Wang, Ligong; Chang, Gregory; Bencardino, Jenny; Babb, James S.; Krasnokutsky, Svetlana; Abramson, Steven; Regatte, Ravinder R.

    2013-01-01

    Purpose To compare and assess subregional, compartmental, and whole T1rho values of menisci in patients with doubtful-minimal [Kellgren-Lawrence (KL) grade 1–2] as compared to moderate-severe (KL3–4) osteoarthritis (OA) and healthy controls at 3T. Materials and Methods 46 subjects were included in the study and subdivided into three subgroups: 16 healthy controls (4 females, 12 males; mean age = 34.4±10.2 years, age range 24–63 years), 20 patients with doubtful-minimal (KL1–2) OA (9 females, 11 males; mean age = 61.9±10.8 years, age range 40–80 years), and 10 patients with moderate-severe (KL3–4) OA (4 females, 6 males; mean age = 71.1±9.6 years, age range 58–89 years). All subjects were evaluated on a 3T MR scanner using a spin-lock-based 3D GRE sequence for T1rho mapping. Clinical proton density (PD)-weighted fast spin echoes (FSE) images in the sagittal (without fat saturation), axial, and coronal (fat-saturated) planes were acquired for cartilage Whole-Organ MR Imaging Score (WORMS) grading. Analysis of covariance (ANCOVA) was performed to determine whether there were any statistically significant differences between subregional, compartmental, and whole T1rho values of meniscus among healthy controls, OA patients with KL1–2 and with KL3–4. Results Lateral anterior (median±inter-quartile range: 26±3 ms) and medial posterior (29±6 ms) meniscus subregions in healthy controls had significantly lower T1rho values (p < 0.05) than the corresponding meniscus subregions in both KL1–2 (29±7 ms and 35±8 ms, respectively) and KL3–4 (30±12 ms and 40±13 ms, respectively) OA subjects. Significantly lower meniscus T1rho values (p < 0.05) were also identified in the medial compartment in healthy controls (28±5 ms) relative to both KL1–2 OA subjects and KL3–4 OA subjects (32±7 ms and 37±7 ms, respectively). The entire meniscus T1rho values in healthy controls (28±4 ms) were significantly lower than those of both KL1–2 and KL3–4 OA

  19. T1 nuclear magnetic relaxation dispersion of hyperpolarized sodium and cesium hydrogencarbonate-(13) C.

    PubMed

    Martínez-Santiesteban, Francisco M; Dang, Thien Phuoc; Lim, Heeseung; Chen, Albert P; Scholl, Timothy J

    2017-09-01

    In vivo pH mapping in tissue using hyperpolarized hydrogencarbonate-(13) C has been proposed as a method to study tumor growth and treatment and other pathological conditions related to pH changes. The finite spin-lattice relaxation times (T1 ) of hyperpolarized media are a significant limiting factor for in vivo imaging. Relaxation times can be measured at standard magnetic fields (1.5 T, 3.0 T etc.), but no such data are available at low fields, where T1 values can be significantly shorter. This information is required to determine the potential loss of polarization as the agent is dispensed and transported from the polarizer to the MRI scanner. The purpose of this study is to measure T1 dispersion from low to clinical magnetic fields (0.4 mT to 3.0 T) of different hyperpolarized hydrogencarbonate formulations previously proposed in the literature for in vivo pH measurements. (13) C-enriched cesium and sodium hydrogencarbonate preparations were hyperpolarized using dynamic nuclear polarization, and the T1 values of different samples were measured at different magnetic field strengths using a fast field-cycling relaxometer and a 3.0 T clinical MRI system. The effects of deuterium oxide as a dissolution medium for sodium hydrogencarbonate were also analyzed. This study finds that the cesium formulation has slightly shorter T1 values compared with the sodium preparation. However, the higher solubility of cesium hydrogencarbonate-(13) C means it can be polarized at greater concentration, using less trityl radical than sodium hydrogencarbonate-(13) C. This study also establishes that the preparation and handling of sodium hydrogencarbonate formulations in relation to cesium hydrogencarbonate is more difficult, due to the higher viscosity and lower achievable concentrations, and that deuterium oxide significantly increases the T1 of sodium hydrogencarbonate solutions. Finally, this work also investigates the influence of pH on the spin-lattice relaxation of cesium

  20. Syntheses, structures, and 1H, 13C{1H} and 119Sn{1H} NMR chemical shifts of a family of trimethyltin alkoxide, amide, halide and cyclopentadienyl compounds

    DOE PAGES

    Lichtscheidl, Alejandro G.; Janicke, Michael T.; Scott, Brian L.; ...

    2015-08-21

    The synthesis and full characterization, including Nuclear Magnetic Resonance (NMR) data (1H, 13C{1H} and 119Sn{1H}), for a series of Me3SnX (X = O-2,6-tBu2C6H3 (1), (Me3Sn)N(2,6-iPr2C6H3) (3), NH-2,4,6-tBu3C6H2 (4), N(SiMe3)2 (5), NEt2, C5Me5 (6), Cl, Br, I, and SnMe3) compounds in benzene-d6, toluene-d8, dichloromethane-d2, chloroform-d1, acetonitrile-d3, and tetrahydrofuran-d8 are reported. The X-ray crystal structures of Me3Sn(O-2,6-tBu2C6H3) (1), Me3Sn(O-2,6-iPr2C6H3) (2), and (Me3Sn)(NH-2,4,6-tBu3C6H2) (4) are also presented. As a result, these compiled data complement existing literature data and ease the characterization of these compounds by routine NMR experiments.

  1. Following Metabolism in Living Microorganisms by Hyperpolarized (1)H NMR.

    PubMed

    Dzien, Piotr; Fages, Anne; Jona, Ghil; Brindle, Kevin M; Schwaiger, Markus; Frydman, Lucio

    2016-09-21

    Dissolution dynamic nuclear polarization (dDNP) is used to enhance the sensitivity of nuclear magnetic resonance (NMR), enabling monitoring of metabolism and specific enzymatic reactions in vivo. dDNP involves rapid sample dissolution and transfer to a spectrometer/scanner for subsequent signal detection. So far, most biologically oriented dDNP studies have relied on hyperpolarizing long-lived nuclear spin species such as (13)C in small molecules. While advantages could also arise from observing hyperpolarized (1)H, short relaxation times limit the utility of prepolarizing this sensitive but fast relaxing nucleus. Recently, it has been reported that (1)H NMR peaks in solution-phase experiments could be hyperpolarized by spontaneous magnetization transfers from bound (13)C nuclei following dDNP. This work demonstrates the potential of this sensitivity-enhancing approach to probe the enzymatic process that could not be suitably resolved by (13)C dDNP MR. Here we measured, in microorganisms, the action of pyruvate decarboxylase (PDC) and pyruvate formate lyase (PFL)-enzymes that catalyze the decarboxylation of pyruvate to form acetaldehyde and formate, respectively. While (13)C NMR did not possess the resolution to distinguish the starting pyruvate precursor from the carbonyl resonances in the resulting products, these processes could be monitored by (1)H NMR at 500 MHz. These observations were possible in both yeast and bacteria in minute-long kinetic measurements where the hyperpolarized (13)C enhanced, via (13)C → (1)H cross-relaxation, the signals of protons binding to the (13)C over the course of enzymatic reactions. In addition to these spontaneous heteronuclear enhancement experiments, single-shot acquisitions based on J-driven (13)C → (1)H polarization transfers were also carried out. These resulted in higher signal enhancements of the (1)H resonances but were not suitable for multishot kinetic studies. The potential of these (1)H-based approaches for

  2. [Management of T1a vocal fold carcinoma].

    PubMed

    Reiter, R; Brosch, S; Smith, E; Pickhard, A

    2013-12-01

    About 2/3 of the larynx carcinomas affect the vocal chords. The main risk factor is smoking. Carcinomas in this localisation often arise from leukoplakias with dysplasia. A typical symptom is dysphonia. Arrest of vibration in microlaryngostroboscopy is a hint that a carcinoma could be present. Transoral laser cordectomy or radiotherapy show equivalent oncological results and results in quality of voice in the treatment of vocal fold carcinoma (T1a). As lymph node and distant metastasis are very rare, follow-up can concentrate on microlaryngoscopy. In case of a suspicious area on the vocal fold, biopsy of the affected tissue is needed to plan correct treatment. The prognosis of the T1 vocal chord carcinoma is quite good with a 5-year survival rate of almost 100%.

  3. An elevated 1-h post- load glucose level during the oral glucose tolerance test detects prediabetes.

    PubMed

    Buysschaert, Martin; Bergman, Michael; Yanogo, Donald; Jagannathan, Ram; Buysschaert, Benoit; Preumont, Vanessa

    The objective of the study was to compare the diagnosis of dysglycemic states by conventional oral glucose tolerance test (OGTT) criteria (fasting and 2-h plasma glucose) with the 1-h post-load plasma glucose level. 34 individuals (mean age: 55±13years; BMI: 27.7±6.3kg/m(2)) at risk for prediabetes were administered a 75g OGTT. Individuals with normal glucose tolerance (NGT) or prediabetes were identified according to fasting and/or 2-h plasma glucose (PG) concentrations. Subsequently, subjects were divided in 2 groups: group 1 (n=21) with a 1-h PG<155mg/dl and group 2 (n=13) with a 1-h PG≥155mg/dl. HOMA was performed to assess β-cell function and insulin sensitivity. NGT or prediabetes based on conventional criteria correlated with the 1-h PG1-h PG≥155mg/dl was associated with higher HbA1c levels (6.1±0.5 vs. 5.5±0.3%, p<0.001) and significantly impaired insulin secretion and hyperbolic product (BxS) on HOMA test vs. 1-h PG<155mg/dl. The 1-h post-load plasma glucose value ≥155mg/dl is strongly associated with conventional criteria for (pre)diabetes and alterations of β-cell function. Copyright © 2016 Diabetes India. Published by Elsevier Ltd. All rights reserved.

  4. Clinical Outcomes in cT1 Micropapillary Bladder Cancer

    PubMed Central

    Willis, DL; Fernandez, MI; Dickstein, RJ; Parikh, S; Shah, JB; Pisters, LL; Guo, CC; Henderson, S; Czerniak, BA; Grossman, HB; Dinney, CP; Kamat, AM

    2015-01-01

    Purpose While many urologists recommend radical cystectomy for patient with micropapillary bladder cancer (MPBC) invading the lamina propria (cT1), contradictory small reports exist regarding the efficacy of conservative management with intravesical BCG for this disease. Herein we report our updated experience with largest series of patients with cT1 MPBC. Materials and Methods An IRB approved review of our cancer database identified 283 patients with MPBC, including 72 staged as cT1N0M0 at diagnosis and initiation of therapy. Survival analysis was performed using Kaplan-Meier estimator and compared using the log-rank test. Results Within this 72 patient cohort, 40 received primary intravesical BCG and 26 underwent upfront radical cystectomy. Patients receiving BCG experienced high rates of disease recurrence (75%) and progression (45%); 35% developed lymph node metastasis. Patients treated with upfront cystectomy had improved survival compared to patients treated with primary BCG (5 year disease specific survival (DSS) of 100% vs. 60% respectively, p=0.006) or patients undergoing delayed cystectomy after recurrence (5 yr. DSS: 62%, p=0.015). Prognosis was especially poor in patients who waited for progression prior to undergoing radical cystectomy, with an estimated 5-year DSS of only 24% and a median survival of 35 months. In patients treated with upfront cystectomy, pathologic upstaging occurred in 27%, including 20% with lymph node metastasis. Conclusions While certain patients with T1 MPBC may respond to intravesical BCG, improved survival is seen in those patients who undergo early radical cystectomy. Further molecular studies are needed to identify subsets of patients able to spare their bladders safely. PMID:25254936

  5. Analysis of the Precision of Variable Flip Angle T1 Mapping with Emphasis on the Noise Propagated from RF Transmit Field Maps

    PubMed Central

    Lee, Yoojin; Callaghan, Martina F.; Nagy, Zoltan

    2017-01-01

    In magnetic resonance imaging, precise measurements of longitudinal relaxation time (T1) is crucial to acquire useful information that is applicable to numerous clinical and neuroscience applications. In this work, we investigated the precision of T1 relaxation time as measured using the variable flip angle method with emphasis on the noise propagated from radiofrequency transmit field (B1+) measurements. The analytical solution for T1 precision was derived by standard error propagation methods incorporating the noise from the three input sources: two spoiled gradient echo (SPGR) images and a B1+ map. Repeated in vivo experiments were performed to estimate the total variance in T1 maps and we compared these experimentally obtained values with the theoretical predictions to validate the established theoretical framework. Both the analytical and experimental results showed that variance in the B1+ map propagated comparable noise levels into the T1 maps as either of the two SPGR images. Improving precision of the B1+ measurements significantly reduced the variance in the estimated T1 map. The variance estimated from the repeatedly measured in vivo T1 maps agreed well with the theoretically-calculated variance in T1 estimates, thus validating the analytical framework for realistic in vivo experiments. We concluded that for T1 mapping experiments, the error propagated from the B1+ map must be considered. Optimizing the SPGR signals while neglecting to improve the precision of the B1+ map may result in grossly overestimating the precision of the estimated T1 values. PMID:28337119

  6. Myocardial T1 Mapping at 3.0T Using an Inversion Recovery Spoiled Gradient Echo Readout and Bloch Equation Simulation with Slice Profile Correction (BLESSPC) T1 Estimation Algorithm

    PubMed Central

    Shao, Jiaxin; Rapacchi, Stanislas; Nguyen, Kim-Lien; Hu, Peng

    2015-01-01

    Purpose To develop an accurate and precise myocardial T1 mapping technique using an inversion recovery spoiled gradient echo readout at 3.0T. Materials and Methods The modified Look-Locker inversion-recovery (MOLLI) sequence was modified to use fast low angle shot (FLASH) readout, incorporating a BLESSPC (Bloch Equation Simulation with Slice Profile Correction) T1 estimation algorithm, for accurate myocardial T1 mapping. The FLASH-MOLLI with BLESSPC fitting was compared to different approaches and sequences with regards to T1 estimation accuracy, precision and image artifact based on simulation, phantom studies, and in vivo studies of 10 healthy volunteers and 3 patients at 3.0T. Results The FLASH-MOLLI with BLESSPC fitting yields accurate T1 estimation (average error = −5.4±15.1 ms, percentage error = −0.5%±1.2%) for T1 from 236–1852 ms and heart rate from 40–100 bpm in phantom studies. The FLASH-MOLLI sequence prevented off-resonance artifacts in all 10 healthy volunteers at 3.0T. In vivo, there was no significant difference between FLASH-MOLLI-derived myocardial T1 values and “ShMOLLI+IE” derived values (1458.9±20.9 ms vs. 1464.1±6.8 ms, p=0.50); However, the average precision by FLASH-MOLLI was significantly better than that generated by “ShMOLLI+IE” (1.84±0.36% variance vs. 3.57±0.94%, p<0.001). Conclusion The FLASH-MOLLI with BLESSPC fitting yields accurate and precise T1 estimation, and eliminates banding artifacts associated with bSSFP at 3.0T. PMID:26214152

  7. Urinary metabolic fingerprint of acute intermittent porphyria analyzed by (1)H NMR spectroscopy.

    PubMed

    Carichon, Mickael; Pallet, Nicolas; Schmitt, Caroline; Lefebvre, Thibaud; Gouya, Laurent; Talbi, Neila; Deybach, Jean Charles; Beaune, Philippe; Vasos, Paul; Puy, Hervé; Bertho, Gildas

    2014-02-18

    (1)H NMR is a nonbiased technique for the quantification of small molecules that could result in the identification and characterization of potential biomarkers with prognostic value and contribute to better understand pathophysiology of diseases. In this study, we used (1)H NMR spectroscopy to analyze the urinary metabolome of patients with acute intermittent porphyria (AIP), an inherited metabolic disorder of heme biosynthesis in which an accumulation of the heme precursors 5-aminolaevulinic acid (ALA) and porphobilinogen (PBG) promotes sudden neurovisceral attacks, which can be life-threatening. Our objectives were (1) to demonstrate the usefulness of (1)H NMR to identify and quantify ALA and PBG in urines from AIP patients and (2) to identify metabolites that would predict the response to AIP crisis treatment and reflect differential metabolic reprogramming. Our results indicate that (1)H NMR can help to diagnose AIP attacks based on the identification of ALA and PBG. We also show that glycin concentration increases in urines from patients with frequent recurrences at the end of the treatment, after an initial decrease, whereas PBG concentration remains low. Although the reasons for this altered are elusive, these findings indicate that a glycin metabolic reprogramming occurs in AIPr patients and is associated with recurrence. Our results validate the proof of concept of the usefulness of (1)H NMR spectroscopy in clinical chemistry for the diagnosis of acute attack of AIP and identify urinary glycin as a potential marker of recurrence of AIP acute attacks.

  8. T1 mapping and survival in systemic light-chain amyloidosis.

    PubMed

    Banypersad, Sanjay M; Fontana, Marianna; Maestrini, Viviana; Sado, Daniel M; Captur, Gabriella; Petrie, Aviva; Piechnik, Stefan K; Whelan, Carol J; Herrey, Anna S; Gillmore, Julian D; Lachmann, Helen J; Wechalekar, Ashutosh D; Hawkins, Philip N; Moon, James C

    2015-01-21

    To assess the prognostic value of myocardial pre-contrast T1 and extracellular volume (ECV) in systemic amyloid light-chain (AL) amyloidosis using cardiovascular magnetic resonance (CMR) T1 mapping. One hundred patients underwent CMR and T1 mapping pre- and post-contrast. Myocardial ECV was calculated at contrast equilibrium (ECV(i)) and 15 min post-bolus (ECVb). Fifty-four healthy volunteers served as controls. Patients were followed up for a median duration of 23 months and survival analyses were performed. Mean ECV(i) was raised in amyloid (0.44 ± 0.12) as was ECV(b) (mean 0.44 ± 0.12) compared with healthy volunteers (0.25 ± 0.02), P < 0.001. Native pre-contrast T1 was raised in amyloid (mean 1080 ± 87 ms vs. 954 ± 34 ms, P < 0.001). All three correlated with pre-test probability of cardiac involvement, cardiac biomarkers, and systolic and diastolic dysfunction. During follow-up, 25 deaths occurred. An ECV(i) of >0.45 carried a hazard ratio (HR) for death of 3.84 [95% confidence interval (CI): 1.53-9.61], P = 0.004 and pre-contrast T1 of >1044 ms = HR 5.39 (95% CI: 1.24-23.4), P = 0.02. Extracellular volume after primed infusion and ECVb performed similarly. Isolated post-contrast T1 was non-predictive. In Cox regression models, ECV(i) was independently predictive of mortality (HR = 4.41, 95% CI: 1.35-14.4) after adjusting for E:E', ejection fraction, diastolic dysfunction grade, and NT-proBNP. Myocardial ECV (bolus or infusion technique) and pre-contrast T1 are biomarkers for cardiac AL amyloid and they predict mortality in systemic amyloidosis. © The Author 2014. Published by Oxford University Press on behalf of the European Society of Cardiology.

  9. Cardiovascular magnetic resonance by non contrast T1-mapping allows assessment of severity of injury in acute myocardial infarction

    PubMed Central

    2012-01-01

    Background Current cardiovascular magnetic resonance (CMR) methods, such as late gadolinium enhancement (LGE) and oedema imaging (T2W) used to depict myocardial ischemia, have limitations. Novel quantitative T1-mapping techniques have the potential to further characterize the components of ischemic injury. In patients with myocardial infarction (MI) we sought to investigate whether state-of the art pre-contrast T1-mapping (1) detects acute myocardial injury, (2) allows for quantification of the severity of damage when compared to standard techniques such as LGE and T2W, and (3) has the ability to predict long term functional recovery. Methods 3T CMR including T2W, T1-mapping and LGE was performed in 41 patients [of these, 78% were ST elevation MI (STEMI)] with acute MI at 12-48 hour after chest pain onset and at 6 months (6M). Patients with STEMI underwent primary PCI prior to CMR. Assessment of acute regional wall motion abnormalities, acute segmental damaged fraction by T2W and LGE and mean segmental T1 values was performed on matching short axis slices. LGE and improvement in regional wall motion at 6M were also obtained. Results We found that the variability of T1 measurements was significantly lower compared to T2W and that, while the diagnostic performance of acute T1-mapping for detecting myocardial injury was at least as good as that of T2W-CMR in STEMI patients, it was superior to T2W imaging in NSTEMI. There was a significant relationship between the segmental damaged fraction assessed by either by LGE or T2W, and mean segmental T1 values (P < 0.01). The index of salvaged myocardium derived by acute T1-mapping and 6M LGE was not different to the one derived from T2W (P = 0.88). Furthermore, the likelihood of improvement of segmental function at 6M decreased progressively as acute T1 values increased (P < 0.0004). Conclusions In acute MI, pre-contrast T1-mapping allows assessment of the extent of myocardial damage. T1-mapping might become an important

  10. Breath-hold black blood quantitative T1rho imaging of liver using single shot fast spin echo acquisition

    PubMed Central

    Chan, Queenie; Wáng, Yì-Xiáng J.

    2016-01-01

    Background Liver fibrosis is a key feature in most chronic liver diseases. T1rho magnetic resonance imaging is a potentially important technique for noninvasive diagnosis, severity grading, and therapy monitoring of liver fibrosis. However, it remains challenging to perform robust T1rho quantification of liver on human subjects. One major reason is that the presence of rich blood signal in liver can cause artificially high T1rho measurement and makes T1rho quantification susceptible to motion. Methods A pulse sequence based on single shot fast/turbo spin echo (SSFSE/SSTSE) acquisition, with theoretical analysis and simulation based on the extended phase graph (EPG) algorithm, was presented for breath-hold single slice quantitative T1rho imaging of liver with suppression of blood signal. The pulse sequence was evaluated in human subjects at 3.0 T with 500 Hz spinlock frequency and time-of-spinlock (TSL) 0, 10, 30 and 50 ms. Results Human scan demonstrated that the entire T1rho data sets with four spinlock time can be acquired within a single breath-hold of 10 seconds with black blood effect. T1rho quantification with suppression of blood signal results in significantly reduced T1rho value of liver compared to the results without blood suppression. Conclusions A signal-to-noise ratio (SNR) efficient pulse sequence was reported for T1rho quantification of liver. The black blood effect, together with a short breath-hold, mitigates the risk of quantification errors as would occur in the conventional methods. PMID:27190769

  11. Response of sensitive human ataxia and resistant T-1 cell lines to accelerated heavy ions

    SciTech Connect

    Tobias, C.A.; Blakely, E.A.; Chang, P.Y.; Lommel, L.; Roots, R.

    1983-07-01

    The radiation dose responses of fibroblast from a patient with Ataxia telangiectasis (AT-2SF) and an established line of human T-1 cells were studied. Nearly monoenergetic accelerated neon and argon ions were used at the Berkeley Bevalac with various residual range values. The LET of the particles varied from 30 keV/..mu..m to over 1000 keV/..mu..m. All Ataxia survival curves were exponential functions of the dose. Their radiosensitivity reached peak values at 100 to 200 keV/..mu..m. Human T-1 cells have effective sublethal damage repair as has been evidenced by split dose experiments, and they are much more resistant to low LET than to high LET radiation. The repair-misrepair model has been used to interpret these results. We have obtained mathematical expressions that describe the cross sections and inactivation coefficients for both human cell lines as a function of the LET and the type of particle used. The results suggest either that high-LET particles induce a greater number of radiolesions per track or that heavy-ions at high LET induce lesions that kill cells more effectively and that are different from those produced at low LET. We assume that the lesions induced in T-1 and Ataxia cells are qualitatively similar and that each cell line attempts to repair these lesions. The result in most irradiated Ataxia cells, however, is either lethal misrepair or incomplete repair leading to cell death. 63 references, 10 figures, 1 table.

  12. Miscibility of nifedipine and hydrophilic polymers as measured by (1)H-NMR spin-lattice relaxation.

    PubMed

    Aso, Yukio; Yoshioka, Sumie; Miyazaki, Tamaki; Kawanishi, Tohru; Tanaka, Kazuyuki; Kitamura, Satoshi; Takakura, Asako; Hayashi, Takashi; Muranushi, Noriyuki

    2007-08-01

    The miscibility of a drug with excipients in solid dispersions is considered to be one of the most important factors for preparation of stable amorphous solid dispersions. The purpose of the present study was to elucidate the feasibility of (1)H-NMR spin-lattice relaxation measurements to assess the miscibility of a drug with excipients. Solid dispersions of nifedipine with the hydrophilic polymers poly(vinylpyrrolidone) (PVP), hydroxypropylmethylcellulose (HPMC) and alpha,beta-poly(N-5-hydroxypentyl)-L-aspartamide (PHPA) with various weight ratios were prepared by spray drying, and the spin-lattice relaxation decay of the solid dispersions in a laboratory frame (T(1) decay) and in a rotating frame (T(1rho) decay) were measured. T(1rho) decay of nifedipine-PVP solid dispersions (3 : 7, 5 : 5 and 7 : 3) was describable with a mono-exponential equation, whereas T(1rho) decay of nifedipine-PHPA solid dispersions (3 : 7, 4 : 6 and 5 : 5) was describable with a bi-exponential equation. Because a mono-exponential T(1rho) decay indicates that the domain sizes of nifedipine and polymer in solid dispersion are less than several nm, it is speculated that nifedipine is miscible with PVP but not miscible with PHPA. All the nifedipine-PVP solid dispersions studied showed a single glass transition temperature (T(g)), whereas two glass transitions were observed for the nifedipine-PHPA solid dispersion (3 : 7), thus supporting the above speculation. For nifedipine-HPMC solid dispersions (3 : 7 and 5 : 5), the miscibility of nifedipine and HPMC could not be determined by DSC measurements due to the lack of obviously evident T(g). In contrast, (1)H-NMR spin-lattice relaxation measurements showed that nifedipine and HPMC are miscible, since T(1rho) decay of the solid dispersions (3 : 7, 5 : 5 and 7 : 3) was describable with a mono-exponential equation. These results indicate that (1)H-NMR spin-lattice relaxation measurements are useful for assessing the miscibility of a drug and an

  13. Probing water environment of Trp59 in ribonuclease T1: insight of the structure-water network relationship.

    PubMed

    Chao, Wei-Chih; Shen, Jiun-Yi; Lu, Jyh-Feng; Wang, Jinn-Shyan; Yang, Hsiao-Ching; Wee, Kevin; Lin, Li-Ju; Kuo, Yi-Ching; Yang, Cheng-Han; Weng, Shih-Hui; Huang, Huai-Ching; Chen, You-Hua; Chou, Pi-Tai

    2015-02-12

    In this study, we used the tryptophan analogue, (2,7-aza)Trp, which exhibits water catalyzed proton transfer isomerization among N(1)-H, N(7)-H, and N(2)-H isomers, to probe the water environment of tryptophan-59 (Trp59) near the connecting loop region of ribonuclease Tl (RNase T1) by replacing the tryptophan with (2,7-aza)Trp. The resulting (2,7-aza)Trp59 triple emission bands and their associated relaxation dynamics, together with relevant data of 7-azatryptophan and molecular dynamics (MD) simulation, lead us to propose two Trp59 containing conformers in RNase T1, namely, the loop-close and loop-open forms. Water is rich in the loop-open form around the proximity of (2,7-aza)Trp59, which catalyzes (2,7-aza)Trp59 proton transfer in the excited state, giving both N(1)-H and N(7)-H isomer emissions. The existence of N(2)-H isomer in the loop-open form, supported by the MD simulation, is mainly due to the specific hydrogen bonding between N(2)-H proton and water molecule that bridges N(2)-H and the amide oxygen of Pro60, forming a strong network. The loop-close form is relatively tight in space, which squeezes water molecules out of the interface of α-helix and β2 strand, joined by the connecting loop region; accordingly, the water-scant environment leads to the sole existence of the N(1)-H isomer emission. MD simulation also points out that the Trp-water pairs appear to preferentially participate in a hydrogen bond network incorporating polar amino acid moieties on the protein surface and bulk waters, providing the structural dynamic features of the connecting loop region in RNase T1.

  14. Mapping pathological changes in brain structure by combining T1- and T2-weighted MR imaging data.

    PubMed

    Ganzetti, Marco; Wenderoth, Nicole; Mantini, Dante

    2015-09-01

    A workflow based on the ratio between standardized T1-weighted (T1-w) and T2-weighted (T2-w) MR images has been proposed as a new tool to study brain structure. This approach was previously used to map structural properties in the healthy brain. Here, we evaluate whether the T1-w/T2-w approach can support the assessment of structural impairments in the diseased brain. We use schizophrenia data to demonstrate the potential clinical utility of the technique. We analyzed T1-w and T2-w images of 36 schizophrenic patients and 35 age-matched controls. These were collected for the Function Biomedical Informatics Research Network (fBIRN) collaborative project, which had an IRB approval and followed the HIPAA guidelines. We computed T1-w/T2-w images for each individual and compared intensities in schizophrenic and control groups on a voxel-wise basis, as well as in regions of interest (ROIs). Our results revealed that the T1-w/T2-w image permits to discriminate brain regions showing group-level differences between patients and controls with greater accuracy than conventional T1-w and T2-w images. Both the ROIs and the voxel-wise analysis showed globally reduced gray and white matter values in patients compared to controls. Significantly reduced values were found in regions such as insula, primary auditory cortex, hippocampus, inferior longitudinal fasciculus, and inferior fronto-occipital fasciculus. Our findings were consistent with previous meta-analyses in schizophrenia corroborating the hypothesis of a potential "disconnection" syndrome in conjunction with structural alterations in local gray matter regions. Overall, our study suggested that the T1-w/T2-w technique permits to reliably map structural differences between the brains of patients and healthy individuals.

  15. Geometrically confined ultrasmall gadolinium oxide nanoparticles boost the T1 contrast ability

    NASA Astrophysics Data System (ADS)

    Ni, Kaiyuan; Zhao, Zhenghuan; Zhang, Zongjun; Zhou, Zijian; Yang, Li; Wang, Lirong; Ai, Hua; Gao, Jinhao

    2016-02-01

    High-performance magnetic resonance imaging (MRI) contrast agents and novel contrast enhancement strategies are urgently needed for sensitive and accurate diagnosis. Here we report a strategy to construct a new T1 contrast agent based on the Solomon-Bloembergen-Morgan (SBM) theory. We loaded the ultrasmall gadolinium oxide nanoparticles into worm-like interior channels of mesoporous silica nanospheres (Gd2O3@MSN nanocomposites). This unique structure endows the nanocomposites with geometrical confinement, high molecular tumbling time, and a large coordinated number of water molecules, which results in a significant enhancement of the T1 contrast with longitudinal proton relaxivity (r1) as high as 45.08 mM-1 s-1. Such a high r1 value of Gd2O3@MSN, compared to those of ultrasmall Gd2O3 nanoparticles and gadolinium-based clinical contrast agents, is mainly attributed to the strong geometrical confinement effect. This strategy provides new guidance for developing various high-performance T1 contrast agents for sensitive imaging and disease diagnosis.High-performance magnetic resonance imaging (MRI) contrast agents and novel contrast enhancement strategies are urgently needed for sensitive and accurate diagnosis. Here we report a strategy to construct a new T1 contrast agent based on the Solomon-Bloembergen-Morgan (SBM) theory. We loaded the ultrasmall gadolinium oxide nanoparticles into worm-like interior channels of mesoporous silica nanospheres (Gd2O3@MSN nanocomposites). This unique structure endows the nanocomposites with geometrical confinement, high molecular tumbling time, and a large coordinated number of water molecules, which results in a significant enhancement of the T1 contrast with longitudinal proton relaxivity (r1) as high as 45.08 mM-1 s-1. Such a high r1 value of Gd2O3@MSN, compared to those of ultrasmall Gd2O3 nanoparticles and gadolinium-based clinical contrast agents, is mainly attributed to the strong geometrical confinement effect. This strategy

  16. Zn2+-dependent redox switch in the intracellular T1-T1 interface of a Kv channel.

    PubMed

    Wang, Guangyu; Strang, Candace; Pfaffinger, Paul J; Covarrubias, Manuel

    2007-05-04

    The thiol-based redox regulation of proteins plays a central role in cellular signaling. Here, we investigated the redox regulation at the Zn(2+) binding site (HX(5)CX(20)CC) in the intracellular T1-T1 inter-subunit interface of a Kv4 channel. This site undergoes conformational changes coupled to voltage-dependent gating, which may be sensitive to oxidative stress. The main results show that internally applied nitric oxide (NO) inhibits channel activity profoundly. This inhibition is reversed by reduced glutathione and suppressed by intracellular Zn(2+), and at least two Zn(2+) site cysteines are required to observe the NO-induced inhibition (Cys-110 from one subunit and Cys-132 from the neighboring subunit). Biochemical evidence suggests strongly that NO induces a disulfide bridge between Cys-110 and Cys-132 in intact cells. Finally, further mutational studies suggest that intra-subunit Zn(2+) coordination involving His-104, Cys-131, and Cys-132 protects against the formation of the inhibitory disulfide bond. We propose that the interfacial T1 Zn(2+) site of Kv4 channels acts as a Zn(2+)-dependent redox switch that may regulate the activity of neuronal and cardiac A-type K(+) currents under physiological and pathological conditions.

  17. Localized double-quantum-filtered 1H NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Thomas, M. A.; Hetherington, H. P.; Meyerhoff, D. J.; Twieg, D. B.

    The image-guided in vivo spectroscopic (ISIS) pulse sequence has been combined with a double-quantum-filter scheme in order to obtain localized and water-suppressed 1H NMR spectra of J-coupled metabolites. The coherence-transfer efficiency associated with the DQ filter for AX and A 3X spin systems is described. Phantom results of carnosine, alanine, and ethanol in aqueous solution are presented. For comparison, the 1H NMR spectrum of alanine in aqueous solution with the binomial (1331, 2662) spin-echo sequence is also shown.

  18. Quantitative analysis of norfloxacin by 1H NMR and HPLC.

    PubMed

    Frackowiak, Anita; Kokot, Zenon J

    2012-01-01

    1H NMR and developed previously HPLC methods were applied to quantitative determination of norfloxacin in veterinary solution form for pigeon. Changes in concentration can lead to significant changes in the 1H chemical shifts of non-exchangeable aromatic protons as a result of extensive self-association phenomena. This chemical shift variation of protons was analyzed and applied in the quantitative determination of norfloxacin. The method is simple, rapid, precise and accurate, and can be used for quality control of this drug.

  19. Simultaneous acquisition of high-contrast and quantitative liver T1 images using 3D phase-sensitive inversion recovery: a feasibility study.

    PubMed

    Fujiwara, Yasuhiro; Maruyama, Hirotoshi; Kosaka, Nobuyuki; Ishimori, Yoshiyuki

    2017-08-01

    Background Tumor-to-liver contrast is low in images of chronically diseased livers because gadolinium-based hepatocyte-specific contrast agents (Gd-EOB-DTPA) accumulate less to hepatocytes. Purpose To determine whether phase-sensitive inversion recovery (PSIR) could improve the T1 contrasts of Gd-based contrast agents and liver parenchyma and simultaneously provide accurate T1 values for abdominal organs. Material and Methods The image contrasts of phantoms with different Gd concentrations that were obtained using PSIR were compared to conventional turbo field echo (TFE) results. T1 value was estimated using PSIR by performing iterations to investigate the two IR magnetization evolutions. The estimated T1 values were validated using IR-spin echo (IR-SE) and Look-Locker (L-L) sequences. In an in vivo study, the liver-to-spleen and liver-to-muscle contrasts of the PSIR and TFE images of seven volunteers were compared, as were the T1 values of liver parenchyma, spleen, and muscle obtained using PSIR and L-L sequences. Results The PSIR images showed T1 contrasts higher than those in the TFE results. The PSIR and IR-SE T1 values were linearly correlated. Additionally, the R1 estimated using PSIR were correlated with those measured using IR-SE and L-L. In the in vivo study, the liver-to-spleen and liver-to-muscle contrasts of PSIR were significantly higher than those obtained using TFE. T1 values of abdominal organs obtained using PSIR and L-L were clearly correlated. Conclusion PSIR may be capable of improving liver image T1 contrasts when Gd-based contrast agents are employed and simultaneously yielding accurate T1 values of abdominal organs.

  20. Low resolution 1H NMR assignment of proton populations in pound cake and its polymeric ingredients.

    PubMed

    Luyts, A; Wilderjans, E; Waterschoot, J; Van Haesendonck, I; Brijs, K; Courtin, C M; Hills, B; Delcour, J A

    2013-08-15

    Based on a model system approach, five different proton populations were distinguished in pound cake crumb using one dimensional low resolution (1)H NMR spectroscopy. In free induction decay (FID) measurements, proton populations were assigned to (i) non-exchanging CH protons of crystalline starch, proteins and crystalline fat and (ii) non-exchanging CH protons of amorphous starch and gluten, which are in little contact with water. In Carr-Purcell-Meiboom-Gill (CPMG) measurements, three proton populations were distinguished. The CPMG population with the lowest mobility and the FID population with the highest mobility represent the same proton population. The two CPMG proton populations with the highest mobility were assigned to exchanging protons (i.e., protons of water, starch, gluten, egg proteins and sugar) and protons of lipids (i.e., protons of egg yolk lipids and amorphous lipid fraction of margarine) respectively. Based on their spin-lattice relaxation times (T1), two dimensional (1)H NMR spectroscopy further resolved the two proton populations with the highest mobility into three and two proton populations, respectively.

  1. Stereotactic biopsy in gliomas guided by 3-tesla 1H-chemical-shift imaging of choline.

    PubMed

    Hermann, Elvis J; Hattingen, Elke; Krauss, Joachim K; Marquardt, Gerhard; Pilatus, Ulrich; Franz, Kea; Setzer, Matthias; Gasser, Thomas; Tews, Dominique S; Zanella, Friedhelm E; Seifert, Volker; Lanfermann, Heinrich

    2008-01-01

    To investigate chemical-shift imaging (CSI) to guide stereotactic biopsy of the choline 'hot spot' in cerebral lesions suggestive of low-grade glioma. Nine patients with hyperintense lesions on T(2)-weighted images of standard magnetic resonance imaging without contrast enhancement underwent advanced magnetic resonance studies. These studies included 3-dimensional T(1)-weighted sequences with contrast enhancement and 2-dimensional (1)H-CSI spectroscopy at 3 T. Signal intensity maps with relative signal intensities for choline were generated. The region with the highest choline signal intensity (the hot spot) was chosen as the target for stereotactic biopsy. The histopathological results were correlated with the increase in choline. All spectroscopic data were of sufficient quality. In 5 instances the neuropathological diagnosis was grade II glioma, according to the WHO classification, and in 4 instances it was grade III glioma. According to the CSI criteria, all grade III gliomas and 4 of the 5 grade II gliomas were classified correctly. One grade II glioma was overestimated by CSI as a high-grade glioma. (1)H-CSI-guided stereotactic biopsy may offer advantages as compared to conventional stereotactic biopsy. The biopsy of the choline hot spot in suggestive low-grade gliomas may help to identify focal points of higher tumor malignancy independent of contrast enhancement. Copyright 2008 S. Karger AG, Basel.

  2. Basal Ganglia T1 Hyperintensity in Hereditary Hemorrhagic Telangiectasia.

    PubMed

    Parvinian, A; Iyer, V N; Pannu, B S; Apala, D R; Wood, C P; Brinjikji, W

    2017-10-01

    The implications of basal ganglia T1 hyperintensity remain unclear in patients with hereditary hemorrhagic telangiectasia. This study was performed to assess the prevalence of this imaging finding in a large cohort of patients with hereditary hemorrhagic telangiectasia and to identify any association between this phenomenon and other disease manifestations. In this retrospective study, we identified all patients at our institution diagnosed with definite hereditary hemorrhagic telangiectasia from 2001 to 2017. Patients who did not undergo brain MR imaging were excluded. Patient demographics, laboratory results, and hereditary hemorrhagic telangiectasia disease characteristics were noted. Basal ganglia hyperintensity was evaluated both qualitatively and quantitatively relative to the signal intensity in the ipsilateral thalami. Statistical analysis was performed with commercially available software. A total of 312 patients (41% men, 59% women; mean age, 51 ± 18 years) with definite hereditary hemorrhagic telangiectasia were identified. Basal ganglia T1 hyperintensity was present in 23.4% of patients and demonstrated a statistically significant association with older age (P < .001), increased hepatic AVMs (P < .001), high cardiac output state (P < .001), hepatic failure (P = .01), elevated peak serum alkaline phosphatase level (P = .03), and increased total bilirubin count (P = .03). There was no significant association with sex, hereditary hemorrhagic telangiectasia genetic mutation status, parkinsonism, or serum transaminase levels. Basal ganglia T1 hyperintensity occurs in >23% of patients with hereditary hemorrhagic telangiectasia and is associated with hepatic vascular malformations, hepatic dysfunction, and elevated cardiac output. The presence of this finding on screening MR imaging in patients with hereditary hemorrhagic telangiectasia should prompt further evaluation for visceral lesions causing arteriovenous shunting. © 2017 by American Journal of

  3. T1w dark blood imaging improves detection of contrast enhancing lesions in multiple sclerosis.

    PubMed

    Thaler, Christian; Schneider, Tanja; Sedlacik, Jan; Kutzner, Daniel; Stellmann, Jan-Patrick; Heesen, Christoph; Fiehler, Jens; Siemonsen, Susanne

    2017-01-01

    In multiple sclerosis (MS) the sensitivity for detection of contrast enhancing lesions (CEL) in T1-weighted scans is essential for diagnostics and therapy decisions. The purpose of our study was to evaluate the sensitivity of T1w MPRAGE scans in comparison to T1w dark blood technique (T1-DB) for CEL in MS. 3T MR imaging was performed in 37 MS patients, including T2-weighted imaging, T1w MPRAGE before and after gadolinium injection (unenhanced-T1 and T1-CE) and T1-DB imaging. After gadolinium application, the T1-DB scan was performed prior to T1-CE. From unenhanced-T1 and T1-CE scans, subtraction images (T1-SUB) were calculated. The number of CEL was determined separately on T1-CE and T1-DB by two raters independently. Lesions only detected on T1-DB scans then were verified on T1-SUB. Only lesions detected by both raters were included in further analysis. In 16 patients, at least one CEL was detected by both rater, either on T1-CE or T1-DB. All lesions that were detected on T1-CE were also detected on T1-DB images. The total number of contrast enhancing lesions detected on T1-DB images (n = 54) by both raters was significantly higher than the corresponding number of lesions identified on T1-CE (n = 27) (p = 0.01); all of these lesions could be verified on SUB images. In 21 patients, no CEL was detected in any of the sequences. The application of T1-DB technique increases the sensitivity for CEL in MS, especially for those lesions that show only subtle increase in intensity after Gadolinium application but remain hypo- or iso-intense to surrounding tissue.

  4. T-1 Test Program Ver. 6.0.1

    SciTech Connect

    Perlinski, Anthony W.

    2004-05-21

    The software allows for easy setup and testing of a variety of RF Electronic Sensor Platforms (ESPs). The software interprets RF messages from the ESP and displays the information in a graphical user interface. This program is used primarily for testing of the T-1 Electronic Sensor Platform. The software imports Electronic Tag Data files which are created from the Electronic Sensor Platform Programmer (ESPP). The software will automatically add sensors to its database when a RF message s received that the program recognizes. Any data that is generated can be stored to a file for later analysis.

  5. The TOTEM T1 read out card motherboard

    NASA Astrophysics Data System (ADS)

    Minutoli, S.; Lo Vetere, M.; Robutti, E.

    2010-12-01

    This article describes the Read Out Card (ROC) motherboard, which is the main component of the T1 forward telescope front-end electronic system. The ROC main objectives are to acquire tracking data and trigger information from the detector. It performs data conversion from electrical to optical format and transfers the data streams to the next level of the system and it implements Slow Control modules which are able to receive, decode and distribute the LHC machine low jitter clock and fast command. The ROC also provides a spy mezzanine connection based on programmable FPGA and USB2.0 for laboratory and portable DAQ debugging system.

  6. Early postnatal myelin content estimate of white matter via T1w/T2w ratio

    NASA Astrophysics Data System (ADS)

    Lee, Kevin; Cherel, Marie; Budin, Francois; Gilmore, John; Zaldarriaga Consing, Kirsten; Rasmussen, Jerod; Wadhwa, Pathik D.; Entringer, Sonja; Glasser, Matthew F.; Van Essen, David C.; Buss, Claudia; Styner, Martin

    2015-03-01

    To develop and evaluate a novel processing framework for the relative quantification of myelin content in cerebral white matter (WM) regions from brain MRI data via a computed ratio of T1 to T2 weighted intensity values. We employed high resolution (1mm3 isotropic) T1 and T2 weighted MRI from 46 (28 male, 18 female) neonate subjects (typically developing controls) scanned on a Siemens Tim Trio 3T at UC Irvine. We developed a novel, yet relatively straightforward image processing framework for WM myelin content estimation based on earlier work by Glasser, et al. We first co-register the structural MRI data to correct for motion. Then, background areas are masked out via a joint T1w and T2 foreground mask computed. Raw T1w/T2w-ratios images are computed next. For purpose of calibration across subjects, we first coarsely segment the fat-rich facial regions via an atlas co-registration. Linear intensity rescaling based on median T1w/T2w-ratio values in those facial regions yields calibrated T1w/T2wratio images. Mean values in lobar regions are evaluated using standard statistical analysis to investigate their interaction with age at scan. Several lobes have strongly positive significant interactions of age at scan with the computed T1w/T2w-ratio. Most regions do not show sex effects. A few regions show no measurable effects of change in myelin content change within the first few weeks of postnatal development, such as cingulate and CC areas, which we attribute to sample size and measurement variability. We developed and evaluated a novel way to estimate white matter myelin content for use in studies of brain white matter development.

  7. Nuclear receptor NR1H3 in familial multiple sclerosis

    PubMed Central

    Wang, Zhe; Sadovnick, A. Dessa; Traboulsee, Anthony L.; Ross, Jay P.; Bernales, Cecily Q.; Encarnacion, Mary; Yee, Irene M.; de Lemos, Madonna; Greenwood, Talitha; Lee, Joshua D.; Wright, Galen; Ross, Colin J.; Zhang, Si; Song, Weihong; Vilariño-Güell, Carles

    2016-01-01

    SUMMARY Multiple sclerosis (MS) is an inflammatory disease characterized by myelin loss and neuronal dysfunction. Despite the aggregation observed in some families, pathogenic mutations have remained elusive. In this study we describe the identification of NR1H3 p.Arg415Gln in seven MS patients from two multi-incident families presenting severe and progressive disease, with an average age at onset of 34 years. Additionally, association analysis of common variants in NR1H3 identified rs2279238 conferring a 1.35-fold increased risk of developing progressive MS. The p.Arg415Gln position is highly conserved in orthologs and paralogs, and disrupts NR1H3 heterodimerization and transcriptional activation of target genes. Protein expression analysis revealed that mutant NR1H3 (LXRA) alters gene expression profiles, suggesting a disruption in transcriptional regulation as one of the mechanisms underlying MS pathogenesis. Our study indicates that pharmacological activation of LXRA or its targets may lead to effective treatments for the highly debilitating and currently untreatable progressive phase of MS. PMID:27253448

  8. Applications of 1H-NMR to Biodiesel Research

    USDA-ARS?s Scientific Manuscript database

    Biodiesel is an alternative diesel fuel derived from vegetable oils, animal fats, or used cooking oils. It is produced by reacting these materials with an alcohol in the presence of a catalyst to give the corresponding mono-alkyl esters. 1H-NMR is a routine analytical method that has been used for...

  9. Complete 1H and 13C spectral assignment of floridoside.

    PubMed

    Simon-Colin, Christelle; Kervarec, Nelly; Pichon, Roger; Deslandes, Eric

    2002-02-11

    Floridoside (2-O-alpha-D-galactopyranosylglycerol) was extracted from the red marine alga Rhodymenia palmata, and purified by ion-exchange chromatography: 1D and 2D NMR spectroscopy experiments were used to unambiguously assign the complete 1H and 13C spectra.

  10. Intermolecular relaxation in glycerol as revealed by field cycling 1H NMR relaxometry dilution experiments.

    PubMed

    Meier, R; Kruk, D; Gmeiner, J; Rössler, E A

    2012-01-21

    (1)H spin-lattice relaxation rates R(1) = 1/T(1) have been measured for partly deuterated glycerol-h(5) diluted in fully deuterated glycerol-h(0) for progressively lower concentrations of glycerol-h(5). By means of the field cycling (FC) technique relaxation dispersion data, R(1)(ω), have been collected for several temperatures in the frequency range of 10 kHz-20 MHz. In order to disclose the spectral shape of the intra- and intermolecular relaxation, extrapolation of the relaxation data to the zero concentration limit has been performed. The paper confirms that the low frequency excess contribution to the total relaxation rate R(1)(ω) previously reported for several liquids is of intermolecular origin and reflects translational motion, whereas the high-frequency part is attributed to molecular rotation. Thus, intra- and intermolecular relaxation contributions are spectrally separated. The intermolecular relaxation itself contains also a contribution from rotational motion, which is due to non-central positions of the interacting nuclei in the molecule. This eccentricity effect is quantitatively reproduced by treating the intermolecular spectral density as a sum of translational-like (described by the free diffusion model) and rotational-like contributions (described by a Cole-Davidson function). Applying frequency-temperature superposition master curves as well as individual relaxation dispersion data, R(1)(ω), are analyzed. It is demonstrated that, in spite of the rotational influence, the translational diffusion coefficients, D(T), can be extracted from the (1)H relaxation dispersion which gives (1)H NMR relaxometry the potential to become a routine technique determining the diffusion coefficient in liquids. © 2012 American Institute of Physics

  11. The use of the T1 sagittal angle in predicting overall sagittal balance of the spine.

    PubMed

    Knott, Patrick T; Mardjetko, Steven M; Techy, Fernando

    2010-11-01

    unexpected, given that cervical lordosis determines head position. Thoracic kyphosis also had a weak correlation (r=0.26) with SVA(C1), which was equally surprising. Lumbar lordosis had a slightly higher correlation (r=0.38), p=.006, than the cervical or thoracic spine. A multiple regression was run on the data to examine the relationship that all these independent variables have on SVA(dens). SPSS (SPSS, Inc., Chicago, IL, USA) was used to create a regression equation using the independent variables of T1 sagittal angle, cervical lordosis, thoracic kyphosis, lumbar lordosis, sacral slope, pelvic incidence, and femoral-sacral angle and the dependent variable of SVA(dens). The model had a strong correlation (r=0.80, r(2)=0.64) and was statistically significant (p<.0001). The T1 sagittal angle was the variable that had the strongest correlation with the SVA(dens) Spearman r=0.65, p<.0001, followed by pelvic incidence, p=.002, and lumbar lordosis, p=.006. We also observed that when the T1 tilt was higher than 25°, all patients had at least 10 cm of positive sagittal imbalance. In addition, patients with negative sagittal balance had mostly low T1 tilt values, usually lower than 13°. The other variables were not shown to have a statically significant influence on SVA. This analysis shows that many factors influence the overall sagittal balance of the patient, but it may be the position of the pelvis and lower spine that have a stronger influence than the position of the upper back and neck. Unfortunately, to our knowledge, there are no studies to date that have established a normal sagittal T1 tilt angle. However, our analysis has shown that when the T1 tilt was higher than 25°, all patients had at least 10 cm of positive sagittal imbalance. It also showed that patients with negative sagittal balance had mostly low T1 tilt values, usually below 13° of angulation. The T1 sagittal angle is a measurement that may be very useful in evaluating sagittal balance, as it was the

  12. Extended ISIS sequences insensitive to T(1) smearing.

    PubMed

    Ljungberg, M; Starck, G; Vikhoff-Baaz, B; Alpsten, M; Ekholm, S; Forssell-Aronsson, E

    2000-10-01

    Image selected in vivo spectroscopy (ISIS) is a volume selection method often used for in vivo (31)P MRS, since it is suitable for measurements of substances with short T(2). However, ISIS can suffer from significant signal contributions caused by T(1) smearing from regions outside the VOI. A computer model was developed to simulate this contamination. The simulation results for the ISIS experiment order implemented in our MR system (ISIS-0) were in agreement with results obtained from phantom measurements. A new extended ISIS experiment order (E-ISIS) was developed, consisting of four "optimal" ISIS experiment orders (ISIS-1 to ISIS-4) performed consecutively with dummy ISIS experiments in between. The simulation results show that contamination due to T(1) smearing is, effectively, eliminated with E-ISIS and is significantly lower than for ISIS-0 and ISIS-1. E-ISIS offers increased accuracy for quantitative and qualitative determination of substances studied using in vivo MRS. Hence, E-ISIS can be valuable for both clinical and research applications.

  13. A general model to calculate the spin-lattice (T1) relaxation time of blood, accounting for haematocrit, oxygen saturation and magnetic field strength.

    PubMed

    Hales, Patrick W; Kirkham, Fenella J; Clark, Christopher A

    2016-02-01

    Many MRI techniques require prior knowledge of the T1-relaxation time of blood (T1bl). An assumed/fixed value is often used; however, T1bl is sensitive to magnetic field (B0), haematocrit (Hct), and oxygen saturation (Y). We aimed to combine data from previous in vitro measurements into a mathematical model, to estimate T1bl as a function of B0, Hct, and Y. The model was shown to predict T1bl from in vivo studies with a good accuracy (± 87 ms). This model allows for improved estimation of T1bl between 1.5-7.0 T while accounting for variations in Hct and Y, leading to improved accuracy of MRI-derived perfusion measurements.

  14. In vivo MEMRI characterization of brain metastases using a 3D Look-Locker T1-mapping sequence

    PubMed Central

    Castets, Charles R.; Koonjoo, Néha; Hertanu, Andreea; Voisin, Pierre; Franconi, Jean-Michel; Miraux, Sylvain; Ribot, Emeline J.

    2016-01-01

    Although MEMRI (Manganese Enhanced MRI) informations were obtained on primary tumors in small animals, MEMRI data on metastases are lacking. Thus, our goal was to determine if 3D Look-Locker T1 mapping was an efficient method to evaluate Mn ions transport in brain metastases in vivo. The high spatial resolution in 3D (156 × 156 × 218 μm) of the sequence enabled to detect metastases of 0.3 mm3. In parallel, the T1 quantitation enabled to distinguish three populations of MDA-MB-231 derived brain metastases after MnCl2 intravenous injection: one with a healthy blood-tumor barrier that did not internalize Mn2+ ions, and two others, which T1 shortened drastically by 54.2% or 24%. Subsequent scans of the mice, enabled by the fast acquisition (23 min), demonstrated that these T1 reached back their pre-injection values in 24 h. Contrarily to metastases, the T1 of U87-MG glioma remained 26.2% shorter for one week. In vitro results supported the involvement of the Transient Receptor Potential channels and the Calcium-Sensing Receptor in the uptake and efflux of Mn2+ ions, respectively. This study highlights the ability of the 3D Look-Locker T1 mapping sequence to study heterogeneities (i) amongst brain metastases and (ii) between metastases and glioma regarding Mn transport. PMID:27995976

  15. The T1-T2 study: evolution of aerosol properties downwind of Mexico City

    NASA Astrophysics Data System (ADS)

    Doran, J. C.; Arnott, W. P.; Barnard, J. C.; Cary, R.; Coulter, R.; Fast, J. D.; Kassianov, E. I.; Kleinman, L.; Laulainen, N. S.; Martin, T.; Paredes-Miranda, G.; Pekour, M. S.; Shaw, W. J.; Smith, D. F.; Springston, S. R.; Yu, X.-Y.

    2006-12-01

    As part of a major atmospheric chemistry and aerosol field program carried out in March of 2006, a study was conducted in the area to the north and northeast of Mexico City to investigate the evolution of aerosols and their associated optical properties in the first few hours after their emission. The focus of the T1-T2 aerosol study was to investigate changes in the specific absorption αABS (absorption per unit mass, with unit of m2 g-1) of black carbon as it aged and became coated with compounds such as sulfate and organic carbon, evolving from an external to an internal mixture. Such evolution has been reported in previous studies. The T1 site was located just to the north of the Mexico City metropolitan area; the T2 site was situated approximately 35 km farther to the northeast. Nephelometers, particle soot absorption photometers, photoacoustic absorption photometers, and organic and elemental carbon analyzers were used to measure the optical properties of the aerosols and the carbon concentrations at each of the sites. Radar wind profilers and radiosonde systems helped to characterize the meteorology and to identify periods when transport from Mexico City over T1 and T2 occurred. Organic and elemental carbon concentrations at T1 showed diurnal cycles reflecting the nocturnal and early morning buildup from nearby sources, while concentrations at T2 appeared to be more affected by transport from Mexico City. Specific absorption during transport periods was lower than during other times, consistent with the likelihood of fresher emissions being found when the winds blew from Mexico City over T1 and T2. The specific absorption at T2 was larger than at T1, which is also consistent with the expectation of more aged particles with encapsulated black carbon being found at the more distant location. In situ measurements of single scattering albedo with an aircraft and a ground station showed general agreement with column-averaged values derived from rotating

  16. The T1-T2 study: evolution of aerosol properties downwind of Mexico City

    NASA Astrophysics Data System (ADS)

    Doran, J. C.; Barnard, J. C.; Arnott, W. P.; Cary, R.; Coulter, R.; Fast, J. D.; Kassianov, E. I.; Kleinman, L.; Laulainen, N. S.; Martin, T.; Paredes-Miranda, G.; Pekour, M. S.; Shaw, W. J.; Smith, D. F.; Springston, S. R.; Yu, X.-Y.

    2007-03-01

    As part of a major atmospheric chemistry and aerosol field program carried out in March 2006, a study was conducted in the area to the north and northeast of Mexico City to investigate the evolution of aerosols and their associated optical properties in the first few hours after their emission. The focus of the T1-T2 aerosol study was to investigate changes in the specific absorption αABS (absorption per unit mass, with unit of m2 g-1) of black carbon as it aged and became coated with compounds such as sulfate and organic carbon, evolving from an external to an internal mixture. Such evolution has been reported in previous studies. The T1 site was located just to the north of the Mexico City metropolitan area; the T2 site was situated approximately 35 km farther to the northeast. Nephelometers, particle soot absorption photometers, photoacoustic absorption spectrometers, and organic and elemental carbon analyzers were used to measure the optical properties of the aerosols and the carbon concentrations at each of the sites. Radar wind profilers and radiosonde systems helped to characterize the meteorology and to identify periods when transport from Mexico City over T1 and T2 occurred. Organic and elemental carbon concentrations at T1 showed diurnal cycles reflecting the nocturnal and early morning buildup from nearby sources, while concentrations at T2 appeared to be more affected by transport from Mexico City. Specific absorption during transport periods was lower than during other times, consistent with the likelihood of fresher emissions being found when the winds blew from Mexico City over T1 and T2. The specific absorption at T2 was larger than at T1, which is also consistent with the expectation of more aged particles with encapsulated black carbon being found at the more distant location. In situ measurements of single scattering albedo with an aircraft and a ground station showed general agreement with column-averaged values derived from rotating shadowband

  17. Interactions of sodium halides with sugars in water: a study of viscosity and (1)H spin-lattice relaxation time.

    PubMed

    Zhuo, Kelei; Liu, Hongxun; Tang, Junming; Chen, Yujuan; Wang, Jianji

    2009-10-15

    Viscosity B-coefficients for sodium halides (NaX, X- = Cl-, Br-, and I-) in aqueous monosaccharides (d-glucose, d-galactose, d-xylose, and d-arabinose) were determined from density and viscosity (eta) measurements at 298.15 K. The contributions of solvent property (B1) and the electrolyte-solvent interaction (B2) to the B-coefficient were also obtained together with molar activation energies (Delta(mu)E0(not equal)) of the electrolytes for viscous flow of the aqueous saccharide-electrolyte solution. In addition, 1H spin-lattice relaxation times (T1) were measured for two glycosides in D2O with and without sodium halides. The results show the interactions between X- and the saccharides are in the following order: Cl- > Br- > I-. A linear relationship is observed between the relaxation rate (1/T1) and electrolyte concentration.

  18. OXYGEN PROTECTION OF BACTERIOPHAGE T1 AGAINST IONIZING RADIATIONS

    PubMed Central

    Bachofer, C. S.; Pottinger, M. Aelred

    1956-01-01

    Bacteriophage T1 was suspended in distilled water and in phosphate buffer, saturated with oxygen, nitrogen, hydrogen, and carbon monoxide, and irradiated with gamma rays and x-rays. Under the same conditions phage was exposed to hydrogen peroxide. Oxygen acted as a protective agent against both irradiation and hydrogen peroxide inactivation. As a protective agent against irradiation, oxygen was more efficient in distilled water than in buffer. The phage was much more sensitive to irradiation in the presence of hydrogen or nitrogen than in the presence of oxygen. Survivals of phage irradiated in suspensions saturated with hydrogen and with nitrogen did not differ significantly. From this it was concluded that oxygen did not protect T1 by removing atomic hydrogen from the irradiated medium, since the hydrogen-saturated medium increased the yield of atomic hydrogen but did not increase the yield of inactivated phage. It was presumed, therefore, that phage is sensitive to OH radicals and this was confirmed by irradiating phage with UV in the presence of hydrogen peroxide and comparing this survival with the survivals obtained from hydrogen peroxide alone and from UV alone. The combined effect of hydrogen peroxide and UV acting simultaneously was greater than the effect attributable to hydrogen peroxide and UV acting separately. Evidence for sensitivity to HO2 radicals was considered, and the effect was attributed chiefly to an oxidizing action since phage sensitivity is greater at higher hydrogen ion concentrations, which favor oxidation by HO2 radicals. Since the OH radical is a more efficient oxidizing agent than O-, the former being favored in an acid medium, the latter in an alkaline medium, and since the phage is more sensitive in the first situation than in the second, the present tests proved the importance of oxidation as the mechanism of inactivation. Since some inactivation was encountered when phage was exposed to reducing agents, independently of

  19. Calibration of myocardial T2 and T1 against iron concentration

    PubMed Central

    2014-01-01

    Background The assessment of myocardial iron using T2* cardiovascular magnetic resonance (CMR) has been validated and calibrated, and is in clinical use. However, there is very limited data assessing the relaxation parameters T1 and T2 for measurement of human myocardial iron. Methods Twelve hearts were examined from transfusion-dependent patients: 11 with end-stage heart failure, either following death (n = 7) or cardiac transplantation (n = 4), and 1 heart from a patient who died from a stroke with no cardiac iron loading. Ex-vivo R1 and R2 measurements (R1 = 1/T1 and R2 = 1/T2) at 1.5 Tesla were compared with myocardial iron concentration measured using inductively coupled plasma atomic emission spectroscopy. Results From a single myocardial slice in formalin which was repeatedly examined, a modest decrease in T2 was observed with time, from mean (±SD) 23.7 ± 0.93 ms at baseline (13 days after death and formalin fixation) to 18.5 ± 1.41 ms at day 566 (p < 0.001). Raw T2 values were therefore adjusted to correct for this fall over time. Myocardial R2 was correlated with iron concentration [Fe] (R2 0.566, p < 0.001), but the correlation was stronger between LnR2 and Ln[Fe] (R2 0.790, p < 0.001). The relation was [Fe] = 5081•(T2)-2.22 between T2 (ms) and myocardial iron (mg/g dry weight). Analysis of T1 proved challenging with a dichotomous distribution of T1, with very short T1 (mean 72.3 ± 25.8 ms) that was independent of iron concentration in all hearts stored in formalin for greater than 12 months. In the remaining hearts stored for <10 weeks prior to scanning, LnR1 and iron concentration were correlated but with marked scatter (R2 0.517, p < 0.001). A linear relationship was present between T1 and T2 in the hearts stored for a short period (R2 0.657, p < 0.001). Conclusion Myocardial T2 correlates well with myocardial iron concentration, which raises the possibility that T2 may provide additive

  20. Efficient dipolar double quantum filtering under magic angle spinning without a 1H decoupling field

    NASA Astrophysics Data System (ADS)

    Courtney, Joseph M.; Rienstra, Chad M.

    2016-08-01

    We present a systematic study of dipolar double quantum (DQ) filtering in 13C-labeled organic solids over a range of magic-angle spinning rates, using the SPC-n recoupling sequence element with a range of n symmetry values from 3 to 11. We find that efficient recoupling can be achieved for values n ⩾ 7, provided that the 13C nutation frequency is on the order of 100 kHz or greater. The decoupling-field dependence was investigated and explicit heteronuclear decoupling interference conditions identified. The major determinant of DQ filtering efficiency is the decoupling interference between 13C and 1H fields. For 13C nutation frequencies greater than 75 kHz, optimal performance is observed without an applied 1H field. At spinning rates exceeding 20 kHz, symmetry conditions as low as n = 3 were found to perform adequately.

  1. Efficient dipolar double quantum filtering under magic angle spinning without a (1)H decoupling field.

    PubMed

    Courtney, Joseph M; Rienstra, Chad M

    2016-08-01

    We present a systematic study of dipolar double quantum (DQ) filtering in (13)C-labeled organic solids over a range of magic-angle spinning rates, using the SPC-n recoupling sequence element with a range of n symmetry values from 3 to 11. We find that efficient recoupling can be achieved for values n⩾7, provided that the (13)C nutation frequency is on the order of 100kHz or greater. The decoupling-field dependence was investigated and explicit heteronuclear decoupling interference conditions identified. The major determinant of DQ filtering efficiency is the decoupling interference between (13)C and (1)H fields. For (13)C nutation frequencies greater than 75kHz, optimal performance is observed without an applied (1)H field. At spinning rates exceeding 20kHz, symmetry conditions as low as n=3 were found to perform adequately.

  2. Performance of the New South Wales Ambulance Service major trauma transport protocol (T1) at an inner city trauma centre.

    PubMed

    Dinh, Michael M; Oliver, Matthew; Bein, Kendall J; Roncal, Susan; Byrne, Christopher M

    2012-08-01

    To evaluate the performance of a newly implemented prehospital trauma triage (T1) protocol in New South Wales for patients transported to an inner city major trauma centre. An observational study was conducted over 1 year. Prehospital data and injury characteristics were collected prospectively for all hospital trauma team activations and injury presentations transported by Ambulance Service of New South Wales. Univariate comparison of T1- and non-T1-transported patients was performed and sensitivity, specificity, overtriage and undertriage rates were calculated. The outcomes studied were Injury Severity Score >15 and major outcome (composite of in-hospital death and/or transferred from the ED to operating theatre or intensive care unit). Factors associated with undertriage were determined with univariate analysis. A total of 2664 ambulance arrivals for trauma were studied with 767(29%) transported on the T1 protocol. T1-transported patients were associated with more severe injury (23% vs 6%, P < 0.001) and major outcomes (30% vs 10%, P < 0.001) compared with non-T1-transported patients. The sensitivity of the T1 protocol for severe injury was 63% with a positive predictive value of 23%. The undertriage and overtriage rates for severe injury were 12% and 77%, respectively. Undertriaged patients were elderly with falls as the predominant mechanism of injury. The sensitivity and undertriage rates associated with the T1 protocol indicate the ongoing need for secondary triage at designated trauma centres and refinement of the protocol to include age as a criterion. © 2012 The Authors. EMA © 2012 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

  3. New T1-based superconductor T1PbSrRCuO without Ca with Tc above 100 K

    NASA Astrophysics Data System (ADS)

    Sheng, Z. Z.; Xin, Y.; Meason, J. M.

    1991-04-01

    Ca-free T1PbSrRCuO samples (R=rare earths) with Tc up to above 100 K were prepared, and studied by resistance and ac susceptibility measurements and by powder x-ray diffraction analyses. A 1212-type phase (Tl1-xPbx)Sr2(Sr1-yRy)Cu2Oz is responsible for the observed supercondcutivity. A rare-earth is required for the formation of the 1212 phase. Pb-dopping is necessary to increase the Tc of the 1212 phase from 90 K to above 100 K.

  4. Geometrically confined ultrasmall gadolinium oxide nanoparticles boost the T(1) contrast ability.

    PubMed

    Ni, Kaiyuan; Zhao, Zhenghuan; Zhang, Zongjun; Zhou, Zijian; Yang, Li; Wang, Lirong; Ai, Hua; Gao, Jinhao

    2016-02-14

    High-performance magnetic resonance imaging (MRI) contrast agents and novel contrast enhancement strategies are urgently needed for sensitive and accurate diagnosis. Here we report a strategy to construct a new T1 contrast agent based on the Solomon-Bloembergen-Morgan (SBM) theory. We loaded the ultrasmall gadolinium oxide nanoparticles into worm-like interior channels of mesoporous silica nanospheres (Gd2O3@MSN nanocomposites). This unique structure endows the nanocomposites with geometrical confinement, high molecular tumbling time, and a large coordinated number of water molecules, which results in a significant enhancement of the T1 contrast with longitudinal proton relaxivity (r1) as high as 45.08 mM(-1) s(-1). Such a high r1 value of Gd2O3@MSN, compared to those of ultrasmall Gd2O3 nanoparticles and gadolinium-based clinical contrast agents, is mainly attributed to the strong geometrical confinement effect. This strategy provides new guidance for developing various high-performance T1 contrast agents for sensitive imaging and disease diagnosis.

  5. Three Dimensional T1, T2, and Proton Density Mapping with Inversion Recovery Balanced SSFP

    PubMed Central

    Newbould, Rexford D.; Skare, Stefan T.; Alley, Marcus T.; Gold, Garry E.; Bammer, Roland

    2010-01-01

    By combining a bSSFP readout with an initial inversion pulse, all three contrast parameters, T1, T2, and proton density (M0), may be rapidly calculated from the signal progression in time. However, here it is shown that this technique is quite sensitive to variation in the applied transmit RF (B1) field, leading to pronounced errors in calculated values. 2D acquisitions are taxed to accurately quantify the relaxation, as the short RF pulses required by SSFP's rapid TR contain a broad spectrum of excitation angles. A 3D excitation using a large diameter excitation coil was able to correctly quantify the parameters. While the extreme B1 sensitivity was previously problematic, and has precluded use of IR-bSSFP for relaxometry, in this work these obstacles were significantly reduced, allowing the rapid quantification of T1, T2, and M0. The results may further be used to simulate image contrast from common sequences, such as a T1-weighted or FLAIR examination. PMID:20692784

  6. Three-dimensional T(1), T(2) and proton density mapping with inversion recovery balanced SSFP.

    PubMed

    Newbould, Rexford D; Skare, Stefan T; Alley, Marcus T; Gold, Garry E; Bammer, Roland

    2010-11-01

    By combining a balanced steady-state free precession (bSSFP) readout with an initial inversion pulse, all three contrast parameters, T(1), T(2) and proton density (M(0)), may be rapidly calculated from the signal progression in time. However, here it is shown that this technique is quite sensitive to variation in the applied transmit RF (B(1)) field, leading to pronounced errors in calculated values. Two-dimensional (2D) acquisitions are taxed to accurately quantify the relaxation, as the short RF pulses required by SSFP's rapid TR contain a broad spectrum of excitation angles. A 3D excitation using a large diameter excitation coil was able to correctly quantify the parameters. While the extreme B(1) sensitivity was previously problematic and has precluded use of IR-bSSFP for relaxometry, in this work these obstacles were significantly reduced, allowing the rapid quantification of T(1), T(2) and M(0). The results may further be used to simulate image contrast from common sequences, such as a T(1)-weighted or fluid-attenuated inversion recovery (FLAIR) examination.

  7. Ethanol-induced fatty liver in the rat examined by in vivo 1H chemical shift selective magnetic resonance imaging and localized spectroscopic methods.

    PubMed

    Ling, M; Brauer, M

    1992-01-01

    In vivo 1H magnetic resonance imaging (MRI), chemical shift selective imaging (CSI), and localized (VOSY) 1H magnetic resonance spectroscopy (MRS) were used to study fatty infiltration in the livers of rats chronically fed an ethanol-containing all-liquid DeCarli-Lieber diet. Conventional total proton MRI showed a somewhat hyperintense liver for ethanol-fed rats, compared with pair-fed controls. CSI showed a dramatic increase in the fat signal intensity for ethanol-treated rats that was fairly homogeneous throughout the liver. However, CSI also showed a substantial decrease in the water signal intensity for the ethanol-treated rats compared to pair-fed control rats. 1H VOSY MR spectra also showed a 5.5-fold increase in the methylene resonance (1.3 ppm) of fat and a 50-70% decrease in the water resonance (4.8 ppm). Relative in vivo proton T1 and T2 relaxation times for the water resonance separate from the fat resonance, determined from modified VOSY experiments, were found to tend to increase and decrease, respectively, for ethanol-treated rat livers compared with controls. The decrease in hepatic water signal intensity could be accounted for by the decrease in T2 and decrease in water density due to the presence of accumulated hepatic fat (approximately 25 mg/g wet weight of liver). When ethanol was withdrawn from the chronically treated rats, fatty infiltration was observed by both CSI and VOSY spectra to revert toward control values with a half-life of 2-4 days. By day 16, however, the signal intensity for hepatic fat was still significantly higher than control levels. In vitro 1H MRS studies of chloroform-methanol extracts confirmed the 5.5-fold increase in total hepatic fat induced by the chronic ethanol treatment, and showed further that triacylglycerols were increased 7.7-fold, cholesterol was increased fourfold, and phospholipids were increased 3.3-fold, compared with liver extracts from pair-fed control rats.

  8. Relationship between knee kinetics during jumping tasks and knee articular cartilage MRI T1rho and T2 relaxation times

    PubMed Central

    Souza, Richard B.; Fang, Charles; Luke, Anthony; Wu, Samuel; Li, Xiaojuan; Majumdar, Sharmila

    2012-01-01

    Background Articular cartilage of young healthy individuals is dynamic and responsive to loading behaviors. The purpose of this study was to evaluate the relationship of cartilage T1ρ and T2 relaxation times with loading kinetics during jumping tasks in healthy young individuals. Methods Fourteen healthy subjects underwent: 1) motion analysis while performing a unilateral hopping task and bilateral drop jumping task; and 2) quantitative imaging using a 3 Tesla MRI for T1ρ and T2 relaxation time analysis. Three dimensional net joint moments and angular impulse was calculated using standard inverse dynamics equations. Average T1ρ and T2 relaxation times and medial-lateral ratios for each were calculated. Multiple regression was used to identify predictors of cartilage relaxation times. Findings Average knee flexion moment during hopping was observed to best predict overall T1ρ (R2=.185) and T2 (R2=.154) values. Peak knee adduction moment during a drop jump was the best predictor of the T1ρ medial-lateral ratio (R2=.220). The T2 medial-lateral ratio was best predicted by average internal rotation moment during the drop jump (R2=.174). Interpretation These data suggest that loads across the knee may affect the biochemistry of the cartilage. In young healthy individuals, higher flexion moments were associated with decreased T1ρ and T2 values, suggesting a potentially beneficial effect. The medial-to-lateral ratio of T1ρ and T2 times appears to be related to the frontal and transverse plane joint mechanics. These data offer promising findings of potentially modifiable parameters associated with cartilage composition. PMID:22115848

  9. Evaluation of MR imaging with T1 and T2* mapping for the determination of hepatic iron overload.

    PubMed

    Henninger, B; Kremser, C; Rauch, S; Eder, R; Zoller, H; Finkenstedt, A; Michaely, H J; Schocke, M

    2012-11-01

    To evaluate MRI using T1 and T2* mapping sequences in patients with suspected hepatic iron overload (HIO). Twenty-five consecutive patients with clinically suspected HIO were retrospectively studied. All underwent MRI and liver biopsy. For the quantification of liver T2* values we used a fat-saturated multi-echo gradient echo sequence with 12 echoes (TR = 200 ms, TE = 0.99 ms +  n × 1.41 ms, flip angle 20°). T1 values were obtained using a fast T1 mapping sequence based on an inversion recovery snapshot FLASH sequence. Parameter maps were analysed using regions of interest. ROC analysis calculated cut-off points at 10.07 ms and 15.47 ms for T2* in the determination of HIO with accuracy 88 %/88 %, sensitivity 84 %/89.5 % and specificity 100 %/83 %. MRI correctly classified 20 patients (80 %). All patients with HIO only had decreased T1 and T2* relaxation times. There was a significant difference in T1 between patients with HIO only and patients with HIO and steatohepatitis (P = 0.018). MRI-based T2* relaxation diagnoses HIO very accurately, even at low iron concentrations. Important additional information may be obtained by the combination of T1 and T2* mapping. It is a rapid, non-invasive, accurate and reproducible technique for validating the evidence of even low hepatic iron concentrations. • Hepatic iron overload causes fibrosis, cirrhosis and increases hepatocellular carcinoma risk. • MRI detects iron because of the field heterogeneity generated by haemosiderin. • T2* relaxation is very accurate in diagnosing hepatic iron overload. • Additional information may be obtained by T1 and T2* mapping.

  10. T1 characteristics of interstitial pulmonary fibrosis on 3T MRI—a predictor of early interstitial change?

    PubMed Central

    Tse, Matthew; Kershaw, Lucy; Semple, Scott; Schembri, Nicola; Chin, Calvin; Murchison, John T.; Hirani, Nik; van Beek, Edwin J. R.

    2016-01-01

    Background Computed tomography (CT) is routinely used for diagnosis and characterisation of idiopathic pulmonary fibrosis (IPF). The technique however has limited sensitivity in detection and monitoring of early fibrotic changes. The aim of this study was to evaluate T1 characteristics in the radiologically diseased lung parenchyma in IPF patient compared to apparently normal parenchyma in both interstitial lung disease (ILD) patients and healthy volunteers and to investigate the feasibility of the technique in prediction of early fibrotic lung changes that may not be visible on CT. Methods Ten patients with IPF underwent high resolution computed tomography (HRCT) and magnetic resonance imaging (MRI) on the same day of attendance. 3T MRI was repeated in seven patients with IPF to test the reproducibility of results. The control group included healthy volunteers (n=10). A modified look-locker inversion-recovery (MOLLI) sequence (124×192 acquisition matrix; 8 mm slice) was performed during a 15–20 s breathhold in a single slice. The position of MR slice was pre-selected where there was CT evidence of normal and fibrotic lung. MOLLI imaging was performed prior to the contrast administration, and at 15, 25, 30 and 35 min post Gadolinium. The imaging data were then processed with a curve-fitting technique to estimate T1 values. T1 values of the apparent fibrotic and normal lung in IPF patients and normal lung were compared. Results Fibrotic lung had a higher pre-contrast T1 than either morphologically normal lung in ILD patients or control lung (P=0.02) in healthy volunteers (1309±123, 1069±71, and 1011±172 ms, respectively). Morphologically normal lung T1 and control lung T1 were not significantly different pre-contrast, however, at 10 min after administration of Gadolinium, control lung had a significantly shorter T1 than either fibrotic or morphologically normal lung (494±34, 670±63, and 619±41 ms, respectively; P=0.001). T1 for fibrotic lung continued to

  11. A Minimal Chimera of Human Cyclin T1 and Tat Binds TAR and Activates Human Immunodeficiency Virus Transcription in Murine Cells

    PubMed Central

    Fujinaga, Koh; Irwin, Dan; Taube, Ran; Zhang, Fan; Geyer, Matthias; Peterlin, B. Matija

    2002-01-01

    The transcriptional elongation of human immunodeficiency virus type 1 (HIV-1) is mediated by the virally encoded transactivator Tat and its cellular cofactor, positive transcription elongation factor b (P-TEFb). The human cyclin T1 (hCycT1) subunit of P-TEFb forms a stable complex with Tat and the transactivation response element (TAR) RNA located at the 5′ end of all viral transcripts. Previous studies have demonstrated that hCycT1 binds Tat in a Zn2+-dependent manner via the cysteine at position 261, which is a tyrosine in murine cyclin T1. In the present study, we mutated all other cysteines and histidines that could be involved in this Zn2+-dependent interaction. Because all of these mutant proteins except hCycT1(C261Y) activated viral transcription in murine cells, no other cysteine or histidine in hCycT1 is responsible for this interaction. Next, we fused the N-terminal 280 residues in hCycT1 with Tat. Not only the full-length chimera but also the mutant hCycT1 with an N-terminal deletion to position 249, which retained the Tat-TAR recognition motif, activated HIV-1 transcription in murine cells. This minimal hybrid mutant hCycT1-Tat protein bound TAR RNA as well as human and murine P-TEFb in vitro. We conclude that this minimal chimera not only reproduces the high-affinity binding among P-TEFb, Tat, and TAR but also will be invaluable for determining the three-dimensional structure of this RNA-protein complex. PMID:12438619

  12. HIST1H2AA — EDRN Public Portal

    Cancer.gov

    HIST1H2AA, a member of the histone 2A family, is a core component of the nucleosome. The nucleosome is a histone octamer containing two molecules each of H2A, H2B, H3 and H4 assembled in one H3-H4 heterotetramer and two H2A-H2B heterodimers. Nucleosomes wrap and compact DNA into chromatin, limiting DNA accessibility to the cellular machineries which require DNA as a template (the octamer wraps approximately 147 bp of DNA). Histones thereby play a central role in transcription regulation, DNA repair, DNA replication and chromosomal stability. DNA accessibility is regulated via a complex set of post-translational modifications of histones, also called histone code, and nucleosome remodeling. The HIST1H2AA gene is intronless and encodes a member of the histone H2A family. Transcripts from this gene contain a palindromic termination element.

  13. 1H NMR Studies of MgH2

    NASA Astrophysics Data System (ADS)

    Itoh, Yutaka; Kado, Ryoichi

    We report on 1H NMR studies of commercially available powder MgH2 exposed to air and maybe humidity, which has been believed to be a promising material for hydrogen storage. The Fourier transform of the free-induction decay of the protons indicatesd superposition of broad and narrow components in the NMR spectrum, while the Fourier transform of the 1H nuclear spin-echo reproduced the narrow component. With cooling down below room temperature, the ratio of the narrow peak to the broad spectrum decreased. The broad spectrum is associated with direct dipolar coupled protons on an inhomogeneous rigid lattice. The narrow peak is associated with interstitial protons with more inhomogeneous surroundings.

  14. T1- and T2-weighted imaging at 8 Tesla.

    PubMed

    Kangarlu, A; Abduljalil, A M; Robitaille, P M

    1999-01-01

    In this work, both T1- and T2-weighted fast imaging methods at 8 T are presented. These include the modified driven equilibrium Fourier transform (MDEFT) and rapid acquisition with relaxation enhancement (RARE) methods, respectively. Axial MDEFT images were acquired with large nutation angles, both partially suppressing gray and white matter and permitting the visualization of vascular structures rich in unsaturated spins. Sagittal RARE images, acquired from the same volunteer, were highly T2-weighted, thus highlighting the CSF. At the same time, they provided good visualization of the corpus callosum, cerebellum, and gray and white matter structures. Importantly, both MDEFT and RARE images could be acquired without violating specific absorption rate guidelines.

  15. Internal disruptions and RHF in IR-T1 tokamak

    SciTech Connect

    Ghoranneviss, M.; Masnavi, M.; Khademian, A.

    1996-12-31

    Sawtooth oscillations are observed on IR-T1 Tokamak during low ql discharge with a disruption time of about 30--60 {micro}s. The q = 1 singular surface occurs at radius 3--3.5 cm and inverted Sawtooth from chords outside this radius. The superimposed (m = 1) oscillation with a frequency of about 19 kHz {approx} 25 kHz, according to the tokamak discharges parameters, preceding the Sawtooth oscillation. One major effect the Sawtooth oscillation is to flatten the temperature and density profiles approximately out to a mixing radius rm = {radical}2 rs,. Furthermore, by applying RHFs (L = 2 and L = 3), the Sawtooth behavior is modified. The magnitude of the weak RHFs used in the experiments did not exceed 1% of Bp. Results showed that the weak RHFs magnetic perturbation would change the MHD instabilities and the Sawtooth behavior, as well as plasma, confinement.

  16. MAIN-BELT COMET P/2012 T1 (PANSTARRS)

    SciTech Connect

    Hsieh, Henry H.; Kaluna, Heather M.; Yang Bin; Haghighipour, Nader; Micheli, Marco; Denneau, Larry; Jedicke, Robert; Kleyna, Jan; Veres, Peter; Wainscoat, Richard J.; Ansdell, Megan; Elliott, Garrett T.; Keane, Jacqueline V.; Meech, Karen J.; Riesen, Timm E.; Sonnett, Sarah; Novakovic, Bojan; Fitzsimmons, Alan; Moskovitz, Nicholas A.; Sheppard, Scott S.; and others

    2013-07-01

    We present initial results from observations and numerical analyses aimed at characterizing the main-belt comet P/2012 T1 (PANSTARRS). Optical monitoring observations were made between 2012 October and 2013 February using the University of Hawaii 2.2 m telescope, the Keck I telescope, the Baade and Clay Magellan telescopes, Faulkes Telescope South, the Perkins Telescope at Lowell Observatory, and the Southern Astrophysical Research Telescope. The object's intrinsic brightness approximately doubles from the time of its discovery in early October until mid-November and then decreases by {approx}60% between late December and early February, similar to photometric behavior exhibited by several other main-belt comets and unlike that exhibited by disrupted asteroid (596) Scheila. We also used Keck to conduct spectroscopic searches for CN emission as well as absorption at 0.7 {mu}m that could indicate the presence of hydrated minerals, finding an upper limit CN production rate of Q{sub CN} < 1.5 Multiplication-Sign 10{sup 23} mol s{sup -1}, from which we infer a water production rate of Q{sub H{sub 2O}}<5 Multiplication-Sign 10{sup 25} mol s{sup -1}, and no evidence of the presence of hydrated minerals. Numerical simulations indicate that P/2012 T1 is largely dynamically stable for >100 Myr and is unlikely to be a recently implanted interloper from the outer solar system, while a search for potential asteroid family associations reveals that it is dynamically linked to the {approx}155 Myr old Lixiaohua asteroid family.

  17. Ultrasonic degradation of 1-H-benzotriazole in water.

    PubMed

    Zúñiga-Benítez, Henry; Soltan, Jafar; Peñuela, Gustavo

    2014-01-01

    This paper reports on the effect of different parameters of ultrasonic power, pollutant initial concentration, pH and the presence of co-existing chemical species (oxygen, nitrogen, ozone, and radical scavengers) on the ultrasonic degradation of the endocrine disruptor 1-H-benzotriazole. Increasing the 1-H-benzotriazole initial concentration from 41.97 to 167.88 μM increased the pollutant degradation rate by 40%. Likewise, a high applied ultrasonic power enhanced the extent of 1-H-benzotriazole removal and its initial degradation rate, which was accelerated in the presence of ozone and oxygen, but inhibited by nitrogen. The most favorable pH for the ultrasonic degradation was acidic media, reaching ∼90% pollutant removal in 2 h. The hydroxyl free radical concentration in the reaction medium was proportional to the ultrasound power and the irradiation time. Kinetic models based on a Langmuir-type mechanism were used to predict the pollutant sonochemical degradation. It was concluded that degradation takes place at both the bubble-liquid interfacial region and in the bulk solution, and OH radicals were the main species responsible for the reaction. Hydroxyl free radicals were generated by water pyrolysis and then diffused into the interfacial region and the bulk solution where most of the solute molecules were present.

  18. Quantitative produced water analysis using mobile 1H NMR

    NASA Astrophysics Data System (ADS)

    Wagner, Lisabeth; Kalli, Chris; Fridjonsson, Einar O.; May, Eric F.; Stanwix, Paul L.; Graham, Brendan F.; Carroll, Matthew R. J.; Johns, Michael L.

    2016-10-01

    Measurement of oil contamination of produced water is required in the oil and gas industry to the (ppm) level prior to discharge in order to meet typical environmental legislative requirements. Here we present the use of compact, mobile 1H nuclear magnetic resonance (NMR) spectroscopy, in combination with solid phase extraction (SPE), to meet this metrology need. The NMR hardware employed featured a sufficiently homogeneous magnetic field, such that chemical shift differences could be used to unambiguously differentiate, and hence quantitatively detect, the required oil and solvent NMR signals. A solvent system consisting of 1% v/v chloroform in tetrachloroethylene was deployed, this provided a comparable 1H NMR signal intensity for the oil and the solvent (chloroform) and hence an internal reference 1H signal from the chloroform resulting in the measurement being effectively self-calibrating. The measurement process was applied to water contaminated with hexane or crude oil over the range 1-30 ppm. The results were validated against known solubility limits as well as infrared analysis and gas chromatography.

  19. A Large Volume Double Channel 1H-X RF Probe for Hyperpolarized Magnetic Resonance at 0.0475 Tesla

    PubMed Central

    Coffey, Aaron M.; Shchepin, Roman V.; Wilkens, Ken; Waddell, Kevin W.; Chekmenev, Eduard Y.

    2012-01-01

    In this work we describe a large volume 340 mL 1H-X magnetic resonance (MR) probe for studies of hyperpolarized compounds at 0.0475 T. 1H/13C and 1H/15N probe configurations are demonstrated with the potential for extension to 1H/129Xe. The primary applications of this probe are preparation and quality assurance of 13C and 15N hyperpolarized contrast agents using PASADENA (parahydrogen and synthesis allow dramatically enhanced nuclear alignment) and other parahydrogen-based methods of hyperpolarization. The probe is efficient and permits 62 μs 13C excitation pulses at 5.3 Watts, making it suitable for portable operation. The sensitivity and detection limits of this probe, tuned to 13C, are compared with a commercial radio frequency (RF) coil operating at 4.7 T. We demonstrate that low field MR of hyperpolarized contrast agents could be as sensitive as conventional high field detection and outline potential improvements and optimization of the probe design for preclinical in vivo MRI. PASADENA application of this low-power probe is exemplified with 13C hyperpolarized 2-hydroxyethyl propionate-1-13C,2,3,3-d3. PMID:22706029

  20. (1)H-magnetic resonance spectroscopy ((1)H-MRS) in methamphetamine dependence and methamphetamine induced psychosis.

    PubMed

    Howells, Fleur M; Uhlmann, Anne; Temmingh, Henk; Sinclair, Heidi; Meintjes, Ernesta; Wilson, Don; Stein, Dan J

    2014-03-01

    Methamphetamine (MA) use has been shown to decrease n-acetyl-aspartate (NAA), a marker of neuronal integrity and viability, on (1)H magnetic resonance spectroscopy ((1)H-MRS). However, little work has compared (1)H-MRS in MA dependent individuals and MA dependent individuals with MA induced psychotic disorder (MAP). Twenty six participants with MA dependence (sixteen without psychosis, ten with psychosis - MAP) and nineteen healthy controls underwent 2D-chemical shift imaging (1)H-MRS, which included voxels in the anterior cingulate cortices (ACC), dorsolateral prefrontal cortices (DLPFC), and frontal white matter. We compared metabolite concentrations relative to phosphocreatine+creatine (PCr+Cr) for n-acetyl-aspartate (NAA), n-acetyl-aspartate+n-acetyl-aspartyl-glutamate (NAA+NAAG), glutamate (Glu), glutamate+glutamine (Glu+Gln), myo-inositol, and glycerophosphocholine+phosphocholine (GPC+PCh) across groups. The MA groups showed significantly decreased relative NAA metabolite concentrations for right ACC and right DLPFC, compared with control group. The MA dependent group only showed significantly decreased choline metabolites for right DLPFC, compared with control group. The MAP group's relative NAA metabolite concentrations were significantly correlated with age of initial use and duration of MA use, these correlates were not apparent in MA dependent group. MA use is associated with decreased neuronal integrity and viability, specifically in the right ACC and right DLPFC. MA dependence showed active neurodegeneration in the right DLPFC, this was not apparent in the MAP group and may be related to the use of antipsychotic medication in the MAP group. The effects of MA use in MAP suggest that age of initial use presents a mismatch of neuronal plasticity, in frontal white vs. gray matter and duration of use relates to decreased neuronal integrity and viability. Further study is warranted from this initial study of (1)H-MRS in MAP, in particular longitudinal

  1. Comparison of post-contrast 3D-T1-MPRAGE, 3D-T1-SPACE and 3D-T2-FLAIR MR images in evaluation of meningeal abnormalities at 3-T MRI.

    PubMed

    Jeevanandham, Balaji; Kalyanpur, Tejas; Gupta, Prashant; Cherian, Mathew

    2017-06-01

    This study was to assess the usefulness of newer three-dimensional (3D)-T1 sampling perfection with application optimized contrast using different flip-angle evolutions (SPACE) and 3D-T2 fluid-attenuated inversion recovery (FLAIR) sequences in evaluation of meningeal abnormalities. 78 patients who presented with high suspicion of meningeal abnormalities were evaluated using post-contrast 3D-T2-FLAIR, 3D-T1 magnetization-prepared rapid gradient-echo (MPRAGE) and 3D-T1-SPACE sequences. The images were evaluated independently by two radiologists for cortical gyral, sulcal space, basal cisterns and dural enhancement. The diagnoses were confirmed by further investigations including histopathology. Post-contrast 3D-T1-SPACE and 3D-T2-FLAIR images yielded significantly more information than MPRAGE images (p < 0.05 for both SPACE and FLAIR images) in detection of meningeal abnormalities. SPACE images best demonstrated abnormalities in dural and sulcal spaces, whereas FLAIR was useful for basal cisterns enhancement. Both SPACE and FLAIR performed equally well in detection of gyral enhancement. In all 10 patients, where both SPACE and T2-FLAIR images failed to demonstrate any abnormality, further analysis was also negative. The 3D-T1-SPACE sequence best demonstrated abnormalities in dural and sulcal spaces, whereas FLAIR was useful for abnormalities in basal cisterns. Both SPACE and FLAIR performed holds good for detection of gyral enhancement. Post-contrast SPACE and FLAIR sequences are superior to the MPRAGE sequence for evaluation of meningeal abnormalities and when used in combination have the maximum sensitivity for leptomeningeal abnormalities. The negative-predictive value is nearly 100%, where no leptomeningeal abnormality was detected on these sequences. Advances in knowledge: Post-contrast 3D-T1-SPACE and 3D-T2-FLAIR images are more useful than 3D-T1-MPRAGE images in evaluation of meningeal abnormalities.

  2. Subclinical cartilage degeneration in young athletes with posterior cruciate ligament injuries detected with T1ρ magnetic resonance imaging mapping.

    PubMed

    Okazaki, Ken; Takayama, Yukihisa; Osaki, Kanji; Matsuo, Yoshio; Mizu-Uchi, Hideki; Hamai, Satoshi; Honda, Hiroshi; Iwamoto, Yukihide

    2015-10-01

    Prediction of the risk of osteoarthritis in asymptomatic active patients with an isolated injury of the posterior cruciate ligament (PCL) is difficult. T1ρ magnetic resonance imaging (MRI) enables the quantification of the proteoglycan content in the articular cartilage. The purpose of this study was to evaluate subclinical cartilage degeneration in asymptomatic young athletes with chronic PCL deficiency using T1ρ MRI. Six athletes with chronic PCL deficiency (median age 17, range 14-36 years) and six subjects without any history of knee injury (median age 31.5, range 24-33 years) were recruited. Regions of interest were placed on the articular cartilage of the tibia and the distal and posterior areas of the femoral condyle, and T1ρ values were calculated. On stress radiographs, the mean side-to-side difference in posterior laxity was 9.8 mm. The T1ρ values at the posterior area of the lateral femoral condyle and the superficial layer of the distal area of the medial and lateral femoral condyle of the patients were significantly increased compared with those of the normal controls (p < 0.05). At the tibial plateau, the T1ρ values in both the medial and lateral compartments were significantly higher in patients compared with those in the normal controls (p < 0.05). T1ρ MRI detected unexpected cartilage degeneration in the well-functioning PCL-deficient knees of young athletes. One should be alert to the possibility of subclinical cartilage degeneration even in asymptomatic patients who show no degenerative changes on plain radiographs or conventional MRI. IV.

  3. Temporal lobectomy for epilepsy: Recovery of the contralateral hippocampus measured by 1H MRS

    PubMed Central

    Vermathen, P.; Ende, G.; Laxer, K.D.; Walker, J.A.; Knowlton, R.C.; Barbaro, N.M.; Matson, G.B.; Weiner, M.W.

    2009-01-01

    1H MRS imaging was obtained from 10 patients with mesial temporal lobe epilepsy before and after surgery. After surgery, metabolic recovery in the contralateral hippocampus was detected. Preoperatively, reduced N-acetylaspartate (p < 0.04) increased after surgery nonsignificantly to equal control values. Cholines increased after surgery (p < 0.02) and creatine–phosphocreatine showed a trend to higher values. The results suggest that the contralateral hippocampus is affected by repeated seizure activity in the ipsilateral hippocampus, rather than presence of bilateral mesial temporal sclerosis. PMID:12196667

  4. MTR and In-vivo 1H-MRS studies on mouse brain with parkinson's disease

    NASA Astrophysics Data System (ADS)

    Yoon, Moon-Hyun; Kim, Hyeon-Jin; Chung, Jin-Yeung; Doo, Ah-Reum; Park, Hi-Joon; Kim, Seung-Nam; Choe, Bo-Young

    2012-12-01

    The aim of this study was to investigate whether the changes in the magnetization transfer ratio (MTR) histogram are related to specific characteristics of Parkinson's disease (PD) and to investigate whether the MTR histogram parameters are associated with neurochemical dysfunction by performing in vivo proton magnetic resonance spectroscopy (1H-MRS). MTR and in vivo 1H-MRS studies were performed on control mice (n = 10) and 1-methyl-1,2,3,6-tetrahydropyridine intoxicated mice (n = 10). All the MTR and in vivo 1H-MRS experiments were performed on a 9.4 T MRI/MRS system (Bruker Biospin, Germany) using a standard head coil. The protondensity fast spin echo (FSE) images and the T2-weighted spin echo (SE) images were acquired with no gap. Outer volume suppression (OVS), combined with the ultra-short echo-time stimulated echo acquisition mode (STEAM), was used for the localized in-vivo 1H-MRS. The quantitative analysis of metabolites was performed from the 1H spectra obtained in vivo on the striatum (ST) by using jMRUI (Lyon, France). The peak height of the MTR histograms in the PD model group was significantly lower than that in the control group (p < 0.05). The midbrain MTR values for volume were lower in the PD group than the control group(p < 0.05). The complex peak (Glx: glutamine+glutamate+ GABA)/creatine (Cr) ratio of the right ST in the PD group was significantly increased as compared to that of the control group. The present study revealed that the peak height of the MTR histogram was significantly decreased in the ST and substantia nigra, and a significant increase in the Gl x /Cr ratio was found in the ST of the PD group, as compared with that of the control group. These findings could reflect the early phase of neuronal dysfunction of neurotransmitters.

  5. Imazalil-cyclomaltoheptaose (beta-cyclodextrin) inclusion complex: preparation by supercritical carbon dioxide and 13C CPMAS and 1H NMR characterization.

    PubMed

    Lai, Simona; Locci, Emanuela; Piras, Alessandra; Porcedda, Silvia; Lai, Adolfo; Marongiu, Bruno

    2003-10-10

    An inclusion complex between imazalil (IMZ), a selected fungicide, and cyclomaltoheptaose (beta-cyclodextrin, betaCD) was obtained using supercritical fluid carbon dioxide. The best preparation conditions were determined, and the inclusion complex was investigated by means of 1H NMR spectroscopy in aqueous solution and 13C CPMAS NMR spectroscopy in the solid state. Information on the geometry of the betaCD/IMZ complex was obtained from ROESY spectroscopy, while the dynamics of the inclusion complex in the kilohertz range was obtained from the proton spin-lattice relaxation times in the rotating frame, T(1rho) (1H).

  6. Europium-engineered iron oxide nanocubes with high T1 and T2 contrast abilities for MRI in living subjects

    NASA Astrophysics Data System (ADS)

    Yang, Lijiao; Zhou, Zijian; Liu, Hanyu; Wu, Changqiang; Zhang, Hui; Huang, Guoming; Ai, Hua; Gao, Jinhao

    2015-04-01

    Magnetic resonance imaging (MRI) contrast agents with both positive (T1) and negative (T2) contrast abilities are needed in clinical diagnosis for fault-free accurate detection of lesions. We report a facile synthesis of europium-engineered iron oxide (EuIO) nanocubes as T1 and T2 contrast agents for MRI in living subjects. The Eu(iii) oxide-embedded iron oxide nanoparticles significantly increase the T1 relaxivity with an enhanced positive contrast effect. EuIO nanocubes with 14 nm in diameter showed a high r1 value of 36.8 mM-1 s-1 with respect to total metal ions (Fe + Eu), which is about 3 times higher than that of Fe3O4 nanoparticles with similar size. Moreover, both r1 and r2 values of EuIO nanocubes can be tuned by varying their sizes and Eu doping ratios. After citrate coating, EuIO nanocubes can provide enhanced T1 and T2 contrast effects in small animals, particularly in the cardiac and liver regions. This work may provide an insightful strategy to design MRI contrast agents with both positive and negative contrast abilities for biomedical applications.Magnetic resonance imaging (MRI) contrast agents with both positive (T1) and negative (T2) contrast abilities are needed in clinical diagnosis for fault-free accurate detection of lesions. We report a facile synthesis of europium-engineered iron oxide (EuIO) nanocubes as T1 and T2 contrast agents for MRI in living subjects. The Eu(iii) oxide-embedded iron oxide nanoparticles significantly increase the T1 relaxivity with an enhanced positive contrast effect. EuIO nanocubes with 14 nm in diameter showed a high r1 value of 36.8 mM-1 s-1 with respect to total metal ions (Fe + Eu), which is about 3 times higher than that of Fe3O4 nanoparticles with similar size. Moreover, both r1 and r2 values of EuIO nanocubes can be tuned by varying their sizes and Eu doping ratios. After citrate coating, EuIO nanocubes can provide enhanced T1 and T2 contrast effects in small animals, particularly in the cardiac and liver

  7. Proton-detected 3D (1)H/(13)C/(1)H correlation experiment for structural analysis in rigid solids under ultrafast-MAS above 60 kHz.

    PubMed

    Zhang, Rongchun; Nishiyama, Yusuke; Ramamoorthy, Ayyalusamy

    2015-10-28

    A proton-detected 3D (1)H/(13)C/(1)H chemical shift correlation experiment is proposed for the assignment of chemical shift resonances, identification of (13)C-(1)H connectivities, and proximities of (13)C-(1)H and (1)H-(1)H nuclei under ultrafast magic-angle-spinning (ultrafast-MAS) conditions. Ultrafast-MAS is used to suppress all anisotropic interactions including (1)H-(1)H dipolar couplings, while the finite-pulse radio frequency driven dipolar recoupling (fp-RFDR) pulse sequence is used to recouple dipolar couplings among protons and the insensitive nuclei enhanced by polarization transfer technique is used to transfer magnetization between heteronuclear spins. The 3D experiment eliminates signals from non-carbon-bonded protons and non-proton-bonded carbons to enhance spectral resolution. The 2D (F1/F3) (1)H/(1)H and 2D (13)C/(1)H (F2/F3) chemical shift correlation spectra extracted from the 3D spectrum enable the identification of (1)H-(1)H proximity and (13)C-(1)H connectivity. In addition, the 2D (F1/F2) (1)H/(13)C chemical shift correlation spectrum, incorporated with proton magnetization exchange via the fp-RFDR recoupling of (1)H-(1)H dipolar couplings, enables the measurement of proximities between (13)C and even the remote non-carbon-bonded protons. The 3D experiment also gives three-spin proximities of (1)H-(1)H-(13)C chains. Experimental results obtained from powder samples of L-alanine and L-histidine ⋅ H2O ⋅ HCl demonstrate the efficiency of the 3D experiment.

  8. Proton-detected 3D 1H/13C/1H correlation experiment for structural analysis in rigid solids under ultrafast-MAS above 60 kHz

    NASA Astrophysics Data System (ADS)

    Zhang, Rongchun; Nishiyama, Yusuke; Ramamoorthy, Ayyalusamy

    2015-10-01

    A proton-detected 3D 1H/13C/1H chemical shift correlation experiment is proposed for the assignment of chemical shift resonances, identification of 13C-1H connectivities, and proximities of 13C-1H and 1H-1H nuclei under ultrafast magic-angle-spinning (ultrafast-MAS) conditions. Ultrafast-MAS is used to suppress all anisotropic interactions including 1H-1H dipolar couplings, while the finite-pulse radio frequency driven dipolar recoupling (fp-RFDR) pulse sequence is used to recouple dipolar couplings among protons and the insensitive nuclei enhanced by polarization transfer technique is used to transfer magnetization between heteronuclear spins. The 3D experiment eliminates signals from non-carbon-bonded protons and non-proton-bonded carbons to enhance spectral resolution. The 2D (F1/F3) 1H/1H and 2D 13C/1H (F2/F3) chemical shift correlation spectra extracted from the 3D spectrum enable the identification of 1H-1H proximity and 13C-1H connectivity. In addition, the 2D (F1/F2) 1H/13C chemical shift correlation spectrum, incorporated with proton magnetization exchange via the fp-RFDR recoupling of 1H-1H dipolar couplings, enables the measurement of proximities between 13C and even the remote non-carbon-bonded protons. The 3D experiment also gives three-spin proximities of 1H-1H-13C chains. Experimental results obtained from powder samples of L-alanine and L-histidine ṡ H2O ṡ HCl demonstrate the efficiency of the 3D experiment.

  9. Prediction of Mechanical Properties and Subjective Consistency of Meningiomas Using T1-T2 Assessment Versus Fractional Anisotropy.

    PubMed

    Ortega-Porcayo, Luis Alberto; Ballesteros-Zebadúa, Paola; Marrufo-Meléndez, Oscar René; Ramírez-Andrade, Juan José; Barges-Coll, Juan; Tecante, Alberto; Ramírez-Gilly, Mariana; Gómez-Amador, Juan Luis

    2015-12-01

    This study aims to evaluate quantitatively the mechanical properties of meningiomas and their correlation with the qualitative surgeon's assessment of consistency, as well as comparing the capability to predict tumor consistency of fractional anisotropy values calculated from the diffusion tensor imaging and T1/T2 signal intensities. Sixteen patients with the diagnosis of intracranial meningioma were included. Fractional anisotropy values were calculated and T1/T2 assessment was performed. The qualitative assessment of the tumor consistency intraoperatively was determined by a neurosurgeon and quantitative assessment was obtained with the Warner-Bratzler mechanical test. Surgeon's qualitative assessment was concordant with the cutting force obtained from the mechanical tests (P = 0.046). There was a high correlation between tumor consistency reported by the surgeon and T1/T2 assessment (0.622/P = 0.01) and a moderate correlation with cutting force (0.532/P = 0.034) and elasticity (0.49/P = 0.05). Fractional anisotropy values for hard tumors were not significantly higher than for soft tumors (P = 0.115). There was no significant correlation between the fractional anisotropy and mechanical measurements (0.192/P = 0.3). Predictions of hard consistency in meningiomas were obtained with a sensitivity of 25% and a specificity of 100% when using the T1/T2 assessment and a sensitivity of 87.5% and a specificity of 50% when using the fractional anisotropy value. Qualitative surgeon's assessment was in accordance with measured mechanical properties. Fractional anisotropy value was not an independent predictor for tumor consistency and was not correlated with the mechanical tests results. T1/T2 assessment was correlated with mechanical properties and it can be used to discriminate very hard or soft tumors. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Proton-detected 3D 14N/14N/1H isotropic shift correlation experiment mediated through 1H-1H RFDR mixing on a natural abundant sample under ultrafast MAS

    NASA Astrophysics Data System (ADS)

    Pandey, Manoj Kumar; Nishiyama, Yusuke

    2015-09-01

    In this contribution, we have demonstrated a proton detection-based approach on a natural abundant powdered L-Histidine HCl-H2O sample at ultrafast magic angle spinning (MAS) to accomplish 14N/14N correlation from a 3D 14N/14N/1H isotropic shift correlation experiment mediated through 1H finite-pulse radio frequency-driven recoupling (fp-RFDR). Herein the heteronuclear magnetization transfer between 14N and 1H has been achieved by HMQC experiment, whereas 14N/14N correlation is attained through enhanced 1H-1H spin diffusion process due to 1H-1H dipolar recoupling during the RFDR mixing. While the use of ultrafast MAS (90 kHz) provides sensitivity enhancement through increased 1H transverse relaxation time (T2), the use of micro-coil probe which can withstand strong 14N radio frequency (RF) fields further improves the sensitivity per unit sample volume.

  11. Main-belt Comet P/2012 T1 (PANSTARRS)

    NASA Astrophysics Data System (ADS)

    Hsieh, Henry H.; Kaluna, Heather M.; Novaković, Bojan; Yang, Bin; Haghighipour, Nader; Micheli, Marco; Denneau, Larry; Fitzsimmons, Alan; Jedicke, Robert; Kleyna, Jan; Vereš, Peter; Wainscoat, Richard J.; Ansdell, Megan; Elliott, Garrett T.; Keane, Jacqueline V.; Meech, Karen J.; Moskovitz, Nicholas A.; Riesen, Timm E.; Sheppard, Scott S.; Sonnett, Sarah; Tholen, David J.; Urban, Laurie; Kaiser, Nick; Chambers, K. C.; Burgett, William S.; Magnier, Eugene A.; Morgan, Jeffrey S.; Price, Paul A.

    2013-07-01

    We present initial results from observations and numerical analyses aimed at characterizing the main-belt comet P/2012 T1 (PANSTARRS). Optical monitoring observations were made between 2012 October and 2013 February using the University of Hawaii 2.2 m telescope, the Keck I telescope, the Baade and Clay Magellan telescopes, Faulkes Telescope South, the Perkins Telescope at Lowell Observatory, and the Southern Astrophysical Research Telescope. The object's intrinsic brightness approximately doubles from the time of its discovery in early October until mid-November and then decreases by ~60% between late December and early February, similar to photometric behavior exhibited by several other main-belt comets and unlike that exhibited by disrupted asteroid (596) Scheila. We also used Keck to conduct spectroscopic searches for CN emission as well as absorption at 0.7 μm that could indicate the presence of hydrated minerals, finding an upper limit CN production rate of Q CN < 1.5 × 1023 mol s-1, from which we infer a water production rate of Q_H_2O<5\\times 10^{25} mol s-1, and no evidence of the presence of hydrated minerals. Numerical simulations indicate that P/2012 T1 is largely dynamically stable for >100 Myr and is unlikely to be a recently implanted interloper from the outer solar system, while a search for potential asteroid family associations reveals that it is dynamically linked to the ~155 Myr old Lixiaohua asteroid family. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration, and made possible by the generous financial support of the W. M. Keck Foundation, the Magellan Telescopes located at Las Campanas Observatory, Chile, and the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inova

  12. T1r3 taste receptor involvement in gustatory neural responses to ethanol and oral ethanol preference

    PubMed Central

    Norman, Meghan B.; Lemon, Christian H.

    2010-01-01

    Elevated alcohol consumption is associated with enhanced preference for sweet substances across species and may be mediated by oral alcohol-induced activation of neurobiological substrates for sweet taste. Here, we directly examined the contribution of the T1r3 receptor protein, important for sweet taste detection in mammals, to ethanol intake and preference and the neural processing of ethanol taste by measuring behavioral and central neurophysiological responses to oral alcohol in T1r3 receptor-deficient mice and their C57BL/6J background strain. T1r3 knockout and wild-type mice were tested in behavioral preference assays for long-term voluntary intake of a broad concentration range of ethanol, sucrose, and quinine. For neurophysiological experiments, separate groups of mice of each genotype were anesthetized, and taste responses to ethanol and stimuli of different taste qualities were electrophysiologically recorded from gustatory neurons in the nucleus of the solitary tract. Mice lacking the T1r3 receptor were behaviorally indifferent to alcohol (i.e., ∼50% preference values) at concentrations typically preferred by wild-type mice (5–15%). Central neural taste responses to ethanol in T1r3-deficient mice were significantly lower compared with C57BL/6J controls, a strain for which oral ethanol stimulation produced a concentration-dependent activation of sweet-responsive NTS gustatory neurons. An attenuated difference in ethanol preference between knockouts and controls at concentrations >15% indicated that other sensory and/or postingestive effects of ethanol compete with sweet taste input at high concentrations. As expected, T1r3 knockouts exhibited strongly suppressed behavioral and neural taste responses to sweeteners but did not differ from wild-type mice in responses to prototypic salt, acid, or bitter stimuli. These data implicate the T1r3 receptor in the sensory detection and transduction of ethanol taste. PMID:20145204

  13. Time-Dependent Changes in T1 during Fracture Healing in Juvenile Rats: A Quantitative MR Approach

    PubMed Central

    Baron, Katharina; Neumayer, Bernhard; Amerstorfer, Eva; Scheurer, Eva; Diwoky, Clemens; Stollberger, Rudolf; Sprenger, Hanna; Weinberg, Annelie M.

    2016-01-01

    Quantitative magnetic resonance imaging (qMRI) offers several advantages in imaging and determination of soft tissue alterations when compared to qualitative imaging techniques. Although applications in brain and muscle tissues are well studied, its suitability to quantify relaxation times of intact and injured bone tissue, especially in children, is widely unknown. The objective observation of a fracture including its age determination can become of legal interest in cases of child abuse or maltreatment. Therefore, the aim of this study is the determination of time dependent changes in intact and corresponding injured bones in immature rats via qMRI, to provide the basis for an objective and radiation-free approach for fracture dating. Thirty-five MR scans of 7 Sprague-Dawley rats (male, 4 weeks old, 100 ± 5 g) were acquired on a 3T MRI scanner (TimTrio, Siemens AG, Erlangen, Germany) after the surgical infliction of an epiphyseal fracture in the tibia. The images were taken at days 1, 3, 7, 14, 28, 42 and 82 post-surgery. A proton density-weighted and a T1-weighted 3D FLASH sequence were acquired to calculate the longitudinal relaxation time T1 of the fractured region and the surrounding tissues. The calculation of T1 in intact and injured bone resulted in a quantitative observation of bone development in intact juvenile tibiae as well as the bone healing process in the injured tibiae. In both areas, T1 decreased over time. To evaluate the differences in T1 behaviour between the intact and injured bone, the relative T1 values (bone-fracture) were calculated, showing clear detectable alterations of T1 after fracture occurrence. These results indicate that qMRI has a high potential not only for clinically relevant applications to detect growth defects or developmental alterations in juvenile bones, but also for forensically relevant applications such as the dating of fractures in cases of child abuse or maltreatment. PMID:27832068

  14. Time-Dependent Changes in T1 during Fracture Healing in Juvenile Rats: A Quantitative MR Approach.

    PubMed

    Baron, Katharina; Neumayer, Bernhard; Amerstorfer, Eva; Scheurer, Eva; Diwoky, Clemens; Stollberger, Rudolf; Sprenger, Hanna; Weinberg, Annelie M

    2016-01-01

    Quantitative magnetic resonance imaging (qMRI) offers several advantages in imaging and determination of soft tissue alterations when compared to qualitative imaging techniques. Although applications in brain and muscle tissues are well studied, its suitability to quantify relaxation times of intact and injured bone tissue, especially in children, is widely unknown. The objective observation of a fracture including its age determination can become of legal interest in cases of child abuse or maltreatment. Therefore, the aim of this study is the determination of time dependent changes in intact and corresponding injured bones in immature rats via qMRI, to provide the basis for an objective and radiation-free approach for fracture dating. Thirty-five MR scans of 7 Sprague-Dawley rats (male, 4 weeks old, 100 ± 5 g) were acquired on a 3T MRI scanner (TimTrio, Siemens AG, Erlangen, Germany) after the surgical infliction of an epiphyseal fracture in the tibia. The images were taken at days 1, 3, 7, 14, 28, 42 and 82 post-surgery. A proton density-weighted and a T1-weighted 3D FLASH sequence were acquired to calculate the longitudinal relaxation time T1 of the fractured region and the surrounding tissues. The calculation of T1 in intact and injured bone resulted in a quantitative observation of bone development in intact juvenile tibiae as well as the bone healing process in the injured tibiae. In both areas, T1 decreased over time. To evaluate the differences in T1 behaviour between the intact and injured bone, the relative T1 values (bone-fracture) were calculated, showing clear detectable alterations of T1 after fracture occurrence. These results indicate that qMRI has a high potential not only for clinically relevant applications to detect growth defects or developmental alterations in juvenile bones, but also for forensically relevant applications such as the dating of fractures in cases of child abuse or maltreatment.

  15. T1r3 taste receptor involvement in gustatory neural responses to ethanol and oral ethanol preference.

    PubMed

    Brasser, Susan M; Norman, Meghan B; Lemon, Christian H

    2010-05-01

    Elevated alcohol consumption is associated with enhanced preference for sweet substances across species and may be mediated by oral alcohol-induced activation of neurobiological substrates for sweet taste. Here, we directly examined the contribution of the T1r3 receptor protein, important for sweet taste detection in mammals, to ethanol intake and preference and the neural processing of ethanol taste by measuring behavioral and central neurophysiological responses to oral alcohol in T1r3 receptor-deficient mice and their C57BL/6J background strain. T1r3 knockout and wild-type mice were tested in behavioral preference assays for long-term voluntary intake of a broad concentration range of ethanol, sucrose, and quinine. For neurophysiological experiments, separate groups of mice of each genotype were anesthetized, and taste responses to ethanol and stimuli of different taste qualities were electrophysiologically recorded from gustatory neurons in the nucleus of the solitary tract. Mice lacking the T1r3 receptor were behaviorally indifferent to alcohol (i.e., ∼50% preference values) at concentrations typically preferred by wild-type mice (5-15%). Central neural taste responses to ethanol in T1r3-deficient mice were significantly lower compared with C57BL/6J controls, a strain for which oral ethanol stimulation produced a concentration-dependent activation of sweet-responsive NTS gustatory neurons. An attenuated difference in ethanol preference between knockouts and controls at concentrations >15% indicated that other sensory and/or postingestive effects of ethanol compete with sweet taste input at high concentrations. As expected, T1r3 knockouts exhibited strongly suppressed behavioral and neural taste responses to sweeteners but did not differ from wild-type mice in responses to prototypic salt, acid, or bitter stimuli. These data implicate the T1r3 receptor in the sensory detection and transduction of ethanol taste.

  16. Complete assignment of NMR data of 22 phenyl-1H-pyrazoles' derivatives.

    PubMed

    de Oliveira, Aline Lima; Alves de Oliveira, Carlos Henrique; Mairink, Laura Maia; Pazini, Francine; Menegatti, Ricardo; Lião, Luciano Morais

    2011-08-01

    Complete assignment of (1)H and (13)C NMR chemical shifts and J((1)H/(1)H and (1)H/(19)F) coupling constants for 22 1-phenyl-1H-pyrazoles' derivates were performed using the concerted application of (1)H 1D and (1)H, (13)C 2D gs-HSQC and gs-HMBC experiments. All 1-phenyl-1H-pyrazoles' derivatives were synthesized as described by Finar and co-workers. The formylated 1-phenyl-1H-pyrazoles' derivatives were performed under Duff's conditions.

  17. (1)H-magnetic resonance spectroscopy in social anxiety disorder.

    PubMed

    Howells, Fleur M; Hattingh, Coenraad J; Syal, Supriya; Breet, Elsie; Stein, Dan J; Lochner, Christine

    2015-04-03

    Social anxiety disorder (SAD) is characterized by excessive anxiety about social interaction or performance situations, leading to avoidance and clinically significant distress. A growing literature on the neurobiology of SAD has suggested that the reward/avoidance basal ganglia circuitry in general and the glutamatergic system in particular may play a role. In the current study, we investigated (1)H-magnetic resonance spectroscopy ((1)H-MRS) concentrations in cortical, striatal, and thalamic circuitry, as well as their associations with measures of social anxiety and related symptoms, in patients with primary SAD. Eighteen adult individuals with SAD and 19 age- and sex- matched controls participated in this study. (1)H-MRS was used to determine relative metabolite concentrations in the anterior cingulate cortex (ACC) using single voxel spectroscopy (reporting relative N-acetyl-aspartate (NAA), N-acetyl-aspartate with N-acetyl-aspartyl-glutamate (NAA+NAAG), glycerophosphocholine with phosphocholine (GPC+PCh), myo-inositol, glutamate (Glu), and glutamate with its precursor glutamine (Glu+Gln)), and the caudate, putamen and thalami bilaterally using two dimensional chemical shift imaging (reporting relative NAA+NAAG and GPC+PCh). Relationships between metabolite concentrations and measures of social anxiety and related symptoms were also determined. Measures of social anxiety included symptom severity, blushing propensity, and gaze anxiety/avoidance. We found, first, decreased relative glutamate concentration in the ACC of SAD and changes in myo-inositol with measures of social anxiety. Second, NAA metabolite concentration was increased in thalamus of SAD, and choline metabolite concentrations were related to measures of social anxiety. Lastly, choline metabolite concentration in the caudate and putamen showed changes in relation to measures of social anxiety. These findings are consistent with evidence that the reward/avoidance basal ganglia circuitry, as well as

  18. Differentiation between cortical atrophy and hydrocephalus using 1H MRS.

    PubMed

    Bluml, S; McComb, J G; Ross, B D

    1997-03-01

    Quantitative 1H MRS to determine cerebral metabolite patterns and MRI to determine CSF flow were applied to 12 patients with ventricular dilation-Group A, cortical atrophy (N = 5); or Group B, hydrocephalus (N = 7)- and in 9 normal controls. While mean brain water (Group A = 80% +/- 6; Group B = 86% +/- 5; normal = 85% +/- 4) did not differ between the two groups of patients and controls, 1H MRS distinguished those patients with cortical atrophy (Group A) (N-acetylaspartate/ creatine (NAA/Cr) = 0.69 +/- 0.17, versus normal = 1.06 +/- 0.16; P < 0.002; [NAA] = 5.9 +/- 1.3 mmoles/kg, versus normal 8.0 +/- 1.4; P < 0.02) from those with hydrocephalus (Group B) (NAA/Cr = 1.16 +/- 0.11; [NAA] = 9.2 +/- 1.2; P > 0.13 and P > 0.07). Lactate levels were elevated in 3/5 patients with cortical atrophy, but in 0/7 of those with hydrocephalus. Mean absolute concentrations (mmoles/kg) of the five major cerebral osmolytes were 41 +/- 4 (Group A), 43 +/- 6 (Group B), and 42 +/- 4 (normal), so that despite massive brain deformation, constant osmolality was maintained. 1H MRS may directly benefit surgical planning in hydrocephalus infants by clearly identifying those with cortical atrophy who do not require CSF diversion. Thinning of the cortical mantle in hydrocephalus may result from osmotically driven reduction in individual cell volumes, (shrinkage), rather than brain-compression.

  19. 1H MR spectroscopy of invasive ductal carcinoma: correlations with FDG PET and histologic prognostic factors.

    PubMed

    Tozaki, Mitsuhiro; Hoshi, Kazuei

    2010-05-01

    The purpose of this article is to assess the histologic prognostic relevance of choline levels obtained using (1)H MR spectroscopy with a 1.5-T MR unit in patients with invasive breast cancer and to compare the observed choline levels with the standardized uptake value obtained using FDG PET. Single-voxel (1)H MR spectroscopy and PET/CT were performed for 50 patients with invasive ductal carcinoma (1.5-3 cm in size). The normalized choline signal was calculated using an external standard method. Proton MR spectroscopy detected the presence of choline in 44 cases. The average normalized choline signal was 1.1 (range, 0-3.9). The average standardized uptake value was 6.5 (range, 1.1-23). The correlation (r) between the normalized choline signal and the standardized uptake value was 0.52 (p < 0.0001). The normalized choline signal was significantly correlated with nuclear grade (p = 0.0002), triple-negative breast cancer status (p = 0.0009), and estrogen receptor negativity (p = 0.007). The standardized uptake value was significantly correlated with nuclear grade (p = 0.0002), estrogen receptor negativity (p = 0.002), and triple-negative breast cancer status (p = 0.009). No significant differences were found between the progesterone receptor-positive and negative groups or between the human epidermal growth factor receptor 2-positive and negative groups. The choline levels obtained using (1)H MR spectroscopy with a 1.5-T unit were well correlated with the standardized uptake value obtained using PET/CT and with the histologic prognostic parameters (nuclear grade, estrogen receptor status, and triple-negative lesion status).

  20. Exploring the 3-piperidin-4-yl-1H-indole scaffold as a novel antimalarial chemotype.

    PubMed

    Santos, Sofia A; Lukens, Amanda K; Coelho, Lis; Nogueira, Fátima; Wirth, Dyann F; Mazitschek, Ralph; Moreira, Rui; Paulo, Alexandra

    2015-09-18

    A series of 3-piperidin-4-yl-1H-indoles with building block diversity was synthesized based on a hit derived from an HTS whole-cell screen against Plasmodium falciparum. Thirty-eight compounds were obtained following a three-step synthetic approach and evaluated for anti-parasitic activity. The SAR shows that 3-piperidin-4-yl-1H-indole is intolerant to most N-piperidinyl modifications. Nevertheless, we were able to identify a new compound (10d) with lead-like properties (MW = 305; cLogP = 2.42), showing antimalarial activity against drug-resistant and sensitive strains (EC50 values ∼ 3 μM), selectivity for malaria parasite and no cross-resistance with chloroquine, thus representing a potential new chemotype for further optimization towards novel and affordable antimalarial drugs.

  1. A mathematical force and moment model of a UH-1H helicopter for flight dynamics simulations

    NASA Technical Reports Server (NTRS)

    Talbot, P. D.; Corliss, L. D.

    1977-01-01

    A model of a UH-1H helicopter was developed to support flight simulations and for developmental work on an avionics system known as V/STOLAND system. Equations and numerical values of constants used to represent the helicopter are presented. Responses to stop inputs of the cyclic and collective controls are shown and compared with flight test data for a UH-1H. The model coefficients were adjusted in an attempt to get a consistant match with the flight time histories at hover and 60 knots. Response matching was obtained at 60 knots, but the matching at hover was not as successful. Pilot evaluations of the model, both fixed and moving base, were made.

  2. (1)H-(13)C NMR-Based Profiling of Biotechnological Starch Utilization.

    PubMed

    Sundekilde, Ulrik K; Meier, Sebastian

    2016-10-04

    Starch is used in food- and nonfood applications as a renewable and degradable source of carbon and energy. Insight into the chemical detail of starch degradation remains challenging as the starch constituents amylose and amylopectin are homopolymers. We show that considerable molecular detail of starch fragmentation can be obtained from multivariate analysis of spectral features in optimized (1)H-(13)C NMR spectroscopy of starch fragments to identify relevant features that distinguish processes in starch utilization. As a case study, we compare the profiles of starch fragments in commercial beer samples. Spectroscopic profiles of homooligomeric starch fragments can be excellent indicators of process conditions. In addition, differences in the structure and composition of starch fragments have predictive value for downstream process output such as ethanol production from starch. Thus, high-resolution (1)H-(13)C NMR spectroscopic profiles of homooligomeric fragment mixtures in conjunction with chemometric methods provide a useful addition to the analytical chemistry toolbox of biotechnological starch utilization.

  3. A 1H NMR spectroscopic study on the tryptophan residues of lysozyme included by glucosyl-β-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Yamamoto, Tatsuyuki; Kobayashi, Teruya; Yoshikiyo, Keisuke; Matsui, Yoshihisa; Takahashi, Tetsuya; Aso, Yuji

    2009-02-01

    A 1H NMR spectroscopic study showed that the side chains of Trp residues of chicken egg white lysozyme in an aqueous solution are included by Glucosyl-β-cyclodextrin (G1-β-CD). The 1H NMR signals due to Trp residues shifted with the addition of G1-β-CD. The addition of methyl α- D-glucopyranoside, which has no inclusion ability, gave different effect on the shift of 1H NMR signals. The 1H NMR signals due to Cys64 and Ile98 were also influenced to a considerable extent with the addition of G1-β-CD, suggesting that these hydrophobic amino acid residues are also included by the CD. The chemical shift values of 1H NMR signals, due to indole rings of tryptophan residues, changed more with the addition of G1-β-CD. The magnitudes of the chemical shift change were different depending on their locations in the protein. The chemical shift values of 1H NMR signals, due to those Trp residues in the active site of the lysozyme were smaller than those locating at relatively near the surface of the protein.

  4. (31) P MR spectroscopic imaging of the human prostate at 7 T: T1 relaxation times, Nuclear Overhauser Effect, and spectral characterization.

    PubMed

    Lagemaat, Miriam W; Maas, Marnix C; Vos, Eline K; Bitz, Andreas K; Orzada, Stephan; Weiland, Elisabeth; van Uden, Mark J; Kobus, Thiele; Heerschap, Arend; Scheenen, Tom W J

    2015-03-01

    Optimization of phosphorus ((31) P) MR spectroscopic imaging (MRSI) of the human prostate at 7 T by the evaluation of T1 relaxation times and the Nuclear Overhauser Effect (NOE) of phosphorus-containing metabolites. Twelve patients with prostate cancer and one healthy volunteer were scanned on a 7 T whole-body system using a (31) P endorectal coil combined with an eight-channel (1) H body array coil. T1 relaxation times were measured using progressive saturation in a two-dimensional localization sequence. (31) P MRSI was performed twice: once without NOE and once with NOE using low-power continuous wave (1) H irradiation to determine NOE enhancements. T1 relaxation times of (31) P metabolites in the human prostate at 7 T varied between 3.0 and 8.3 s. Positive but variable NOE enhancements were measured for most metabolites. Remarkably, the (31) P MR spectra showed two peaks in chemical shift range of inorganic phosphate. Knowledge of T1 relaxation times and NOE enhancements enables protocol optimization for (31) P MRSI of the prostate at 7 T. With a strongly reduced (31) P flip angle (≤ 45°), a (31) P MRSI dataset with optimal signal-to-noise ratio per unit time can be obtained within 15 minutes. The NOE enhancement can improve fitting accuracy, but its variability requires further investigation. © 2014 Wiley Periodicals, Inc.

  5. NMR properties of human median nerve at 3 T: proton density, T1, T2, and magnetization transfer.

    PubMed

    Gambarota, Giulio; Mekle, Ralf; Mlynárik, Vladimír; Krueger, Gunnar

    2009-04-01

    To measure the proton density (PD), the T1 and T2 relaxation time, and magnetization transfer (MT) effects in human median nerve at 3 T and to compare them with the corresponding values in muscle. Measurements of the T1 and T2 relaxation time were performed with an inversion recovery and a Carr-Purcell-Meiboom-Gill (CPMG) imaging sequence, respectively. The MT ratio was measured by acquiring two sets of 3D spoiled gradient-echo images, with and without a Gaussian saturation pulse. The median nerve T1 was 1410 +/- 70 msec. The T2 decay consisted of two components, with average T2 values of 26 +/- 2 msec and 96 +/- 3 msec and normalized amplitudes of 78 +/- 4% and 22 +/- 4%, respectively. The dominant component is likely to reflect myelin water and connective tissue, and the less abundant component originates possibly from intra-axonal water protons. The value of proton density of MRI-visible protons in median nerve was 81 +/- 3% that of muscle. The MT ratio in median nerve (40.3 +/- 2.0%) was smaller than in muscle (45.4 +/- 0.5%). MRI-relevant properties, such as PD, T1 and T2 relaxation time, and MT ratio were measured in human median nerve at 3 T and were in many respects similar to those of muscle.

  6. Flowing Foam: T1 events and solid-liquid transitions.

    NASA Astrophysics Data System (ADS)

    Dennin, Michael

    2005-11-01

    Flowing aqueous foam is found in many applications ranging from oil recovery, to fire fighting, to spreading shaving cream. Aqueous foam consists of gas bubbles with liquid walls. One of the striking features of foam is that despite being composed entirely of fluids, its mechanical properties are either those of a solid (elastic response) or fluid (viscous flow), depending on the nature of the applied stress and strains. We study the transition between these two regimes using a model foam system: bubble rafts. Bubble rafts are a single layer of bubbles floating on the air-water surface. This allows us to track the motion of all the bubbles during flow. In this talk, we will present two main results. First, we will discuss the observation of the coexistence between a solid-like and fluid-like state during flow. Second, we will discuss the role played by nonlinear, topological rearrangements, known as T1 events, in determining the mechanical response of the system.

  7. Mirnov oscillation analysis in IR-T1 tokamak

    SciTech Connect

    Ghoranneviss, M.; Khademian, A.

    1996-12-31

    Tokamak discharges are usually rather turbulent with a large spectrum of electric and magnetic fluctuations. Mirnov oscillations are caused by rotating magnetic island inside the plasma column originated by resistive instabilities. Depending on the size of the plasma column, the frequency spectrum of Mirnov oscillation is in the range from a few to tens of kHz. The authors employ the technique to analyze signals measured in the IR-T1 tokamak without and with resonant helical field (RHF). The time-resolved analysis just described applies to the time series of the signal produced by each Mirnov pick-up coil. They see that the resonant helical field has almost no influence on the plasma current and loop voltage and there is a slight decrease of the floating potential at plasma edge. The characteristic frequency of poloidal propagation of the magnetohydrodynamic (MHD) fluctuations can be determined by using the correlation techniques described. For this calculation they have used the signals from the coils located on vacuum chamber with low magnetic field because they are better correlated than the one from the coils in the high field side. They have shown that time-resolved spectral analysis can be easily applied to analyze the (MHD) oscillations in tokamak.

  8. Generalized min-max bound-based MRI pulse sequence design framework for wide-range T1 relaxometry: A case study on the tissue specific imaging sequence

    PubMed Central

    Buck, John R.; Ikonomidou, Vasiliki N.

    2017-01-01

    This paper proposes a new design strategy for optimizing MRI pulse sequences for T1 relaxometry. The design strategy optimizes the pulse sequence parameters to minimize the maximum variance of unbiased T1 estimates over a range of T1 values using the Cramér-Rao bound. In contrast to prior sequences optimized for a single nominal T1 value, the optimized sequence using our bound-based strategy achieves improved precision and accuracy for a broad range of T1 estimates within a clinically feasible scan time. The optimization combines the downhill simplex method with a simulated annealing process. To show the effectiveness of the proposed strategy, we optimize the tissue specific imaging (TSI) sequence. Preliminary Monte Carlo simulations demonstrate that the optimized TSI sequence yields improved precision and accuracy over the popular driven-equilibrium single-pulse observation of T1 (DESPOT1) approach for normal brain tissues (estimated T1 700–2000 ms at 3.0T). The relative mean estimation error (MSE) for T1 estimation is less than 1.7% using the optimized TSI sequence, as opposed to less than 7.0% using DESPOT1 for normal brain tissues. The optimized TSI sequence achieves good stability by keeping the MSE under 7.0% over larger T1 values corresponding to different lesion tissues and the cerebrospinal fluid (up to 5000 ms). The T1 estimation accuracy using the new pulse sequence also shows improvement, which is more pronounced in low SNR scenarios. PMID:28222197

  9. Improved 3D Look-Locker Acquisition Scheme and Angle Map Filtering Procedure for T1 Estimation

    PubMed Central

    Hui, CheukKai; Esparza-Coss, Emilio; Narayana, Ponnada A

    2013-01-01

    The 3D Look-Locker (LL) acquisition is a widely used fast and efficient T1 mapping method. However, the multi-shot approach of 3D LL acquisition can introduce reconstruction artifacts that result in intensity distortions. Traditional 3D LL acquisition generally utilizes centric encoding scheme that is limited to a single phase encoding direction in the k-space. To optimize the k-space segmentation, an elliptical scheme with two phase encoding directions is implemented for the LL acquisition. This elliptical segmentation can reduce the intensity errors in the reconstructed images and improve the final T1 estimation. One of the major sources of error in LL based T1 estimation is lack of accurate knowledge of the actual flip angle. Multi-parameter curve fitting procedure can account for some of the variability in the flip angle. However, curve fitting can also introduce errors in the estimated flip angle that can result in incorrect T1 values. A filtering procedure based on goodness of fit (GOF) is proposed to reduce the effect of false flip angle estimates. Filtering based on the GOF weighting can remove likely incorrect angles that result in bad curve fit. Simulation, phantom, and in-vivo studies have demonstrated that these techniques can improve the accuracy of 3D LL T1 estimation. PMID:23784967

  10. Why are sweet proteins sweet? Interaction of brazzein, monellin and thaumatin with the T1R2-T1R3 receptor.

    PubMed

    Temussi, Piero Andrea

    2002-08-28

    Sweet tasting proteins interact with the same receptor that binds small molecular weight sweeteners, the T1R2-T1R3 G-protein coupled receptor, but the key groups on the protein surface responsible for the biological activity have not yet been identified. I propose that sweet proteins, contrary to small ligands, do not bind to the 'glutamate-like' pocket but stabilize the free form II of the T1R2-T1R3 receptor by attachment to a secondary binding site. Docking of brazzein, monellin and thaumatin with a model of the T1R2-T1R3 sweet taste receptor shows that the most likely complexes can indeed stabilize the active form of the receptor.

  11. Controls on compound specific 2H/1H of leaf waxes along a North American monsoonal transect

    NASA Astrophysics Data System (ADS)

    Berke, M. A.; Tipple, B. J.; Hambach, B.; Ehleringer, J. R.

    2013-12-01

    The use of hydrogen isotope ratios of sedimentary n-alkanes from leaf waxes has become an important method for the reconstruction of paleohydrologic conditions. Ideally, the relationship between lipid 2H/1H values and source water is one-to-one. But the extent to which the 2H/1H values are altered between initial source water and lipid 2H/1H values varies by plant type and environment. Additionally, these variables may be confounded by use of varied source waters by plants in the same ecosystem. Here, we use a transect study across the arid southwestern landscape of the United States, which is heavily influenced by the North American Monsoon, to study the variability in 2H/1H values of leaf waxes in co-occurring plants from Tucson, Arizona to Salt Lake City, Utah. Perennials, including rabbit brush (Chrysothamnus nauseosus), sagebrush (Artemisia tridentata), and gambel oak (Quercus gambelii) and an annual plant, sunflower (Helianthus annuus), were chosen for their wide geographic distribution along the entire transect. Our results indicate that n-alkane distribution for each plant was similar and generally showed no relationship to environmental variables (elevation, mean annual precipitation, latitude, and temperature). However, we find evidence of n-alkane 2H/1H value relating to transect latitude, a relationship that is weaker for all samples combined than the strong individual correlation for each plant species. Further, these 2H/1H values suggest that not all plants in the monsoon region utilize monsoon-delivered precipitation. These results imply an adaptation to discontinuous spatial coverage and amount of monsoonal precipitation and suggest care must be taken when assuming consistent source water for different plants, particularly in regions with highly seasonal precipitation delivery.

  12. T1 Recovery Is Predominantly Found in Black Holes and Is Associated with Clinical Improvement in Patients with Multiple Sclerosis.

    PubMed

    Thaler, C; Faizy, T D; Sedlacik, J; Holst, B; Stürner, K; Heesen, C; Stellmann, J-P; Fiehler, J; Siemonsen, S

    2017-02-01

    Quantitative MR imaging parameters help to evaluate disease progression in multiple sclerosis and increase correlation with clinical disability. We therefore hypothesized that T1 values might be a marker for ongoing tissue damage or even remyelination and may help increase clinical correlation. MR imaging was performed in 17 patients with relapsing-remitting MS at baseline and after 12 months of starting immunotherapy with dimethyl fumarate. On baseline images, lesion segmentation was performed for normal-appearing white matter, T2 hyperintense (FLAIR lesions), T1 hypointense (black holes), and contrast-enhancing lesions, and T1 relaxation times were obtained at baseline and after 12 months. Changes in clinical status were assessed by using the Expanded Disability Status Scale and Symbol Digit Modalities Test at both dates (Expanded Disability Status Scale-difference/Symbol Digit Modalities Test-diff). The highest T1 relaxation time at baseline was measured in black holes (1460.2 ± 209.46 ms) followed by FLAIR lesions (1400.38 ± 189.1 ms), pure FLAIR lesions (1327.5 ± 210.04 ms), contrast-enhancing lesions (1205.59 ± 199.95 ms), and normal-appearing white matter (851.34 ± 30.61 ms). After 12 months, T1 values had decreased significantly in black holes (1369.4 ± 267.81 ms), contrast-enhancing lesions (1079.57 ± 183.36 ms) (both P < .001), and normal-appearing white matter (841.98 ± 36.1 ms, P = .006). With the Jonckheere-Terpstra Test, better clinical scores were associated with decreasing T1 relaxation times in black holes (P < .05). T1 relaxation time is a useful quantitative MR imaging technique, which helps detect changes in MS lesions with time. We assume that these changes are associated with the degree of myelination within the lesions themselves and are pronounced in black holes. Additionally, decreasing T1 values in black holes were associated with clinical improvement. © 2017 by American Journal of Neuroradiology.

  13. Metabolomic insight into soy sauce through (1)H NMR spectroscopy.

    PubMed

    Ko, Bong-Kuk; Ahn, Hyuk-Jin; van den Berg, Frans; Lee, Cherl-Ho; Hong, Young-Shick

    2009-08-12

    Soy sauce, a well-known seasoning in Asia and throughout the world, consists of many metabolites that are produced during fermentation or aging and that have various health benefits. However, their comprehensive assessment has been limited due to targeted or instrumentally specific analysis. This paper presents for the first time a metabolic characterization of soy sauce, especially that aged up to 12 years, to obtain a global understanding of the metabolic variations through (1)H NMR spectroscopy coupled with multivariate pattern recognition techniques. Elevated amino acids and organic acids and the consumption of carbohydrate were associated with continuous involvement of microflora in aging for 12 years. In particular, continuous increases in the levels of betaine were found during aging for up to 12 years, demonstrating that microbial- or enzyme-related metabolites were also coupled with osmotolerant or halophilic bacteria present during aging. This work provides global insights into soy sauce through a (1)H NMR-based metabolomic approach that enhances the current understanding of the holistic metabolome and allows assessment of soy sauce quality.

  14. Profiling formulated monoclonal antibodies by (1)H NMR spectroscopy.

    PubMed

    Poppe, Leszek; Jordan, John B; Lawson, Ken; Jerums, Matthew; Apostol, Izydor; Schnier, Paul D

    2013-10-15

    Nuclear magnetic resonance (NMR) is arguably the most direct methodology for characterizing the higher-order structure of proteins in solution. Structural characterization of proteins by NMR typically utilizes heteronuclear experiments. However, for formulated monoclonal antibody (mAb) therapeutics, the use of these approaches is not currently tenable due to the requirements of isotope labeling, the large size of the proteins, and the restraints imposed by various formulations. Here, we present a new strategy to characterize formulated mAbs using (1)H NMR. This method, based on the pulsed field gradient stimulated echo (PGSTE) experiment, facilitates the use of (1)H NMR to generate highly resolved spectra of intact mAbs in their formulation buffers. This method of data acquisition, along with postacquisition signal processing, allows the generation of structural and hydrodynamic profiles of antibodies. We demonstrate how variation of the PGSTE pulse sequence parameters allows proton relaxation rates and relative diffusion coefficients to be obtained in a simple fashion. This new methodology can be used as a robust way to compare and characterize mAb therapeutics.

  15. T1 Mapping by CMR Imaging: From Histological Validation to Clinical Implication.

    PubMed

    Kammerlander, Andreas A; Marzluf, Beatrice A; Zotter-Tufaro, Caroline; Aschauer, Stefan; Duca, Franz; Bachmann, Alina; Knechtelsdorfer, Klaus; Wiesinger, Matthias; Pfaffenberger, Stefan; Greiser, Andreas; Lang, Irene M; Bonderman, Diana; Mascherbauer, Julia

    2016-01-01

    The purpose of this study was to prospectively investigate the diagnostic and prognostic impact of cardiac magnetic resonance (CMR) T1 mapping and validate it against left ventricular biopsies. Extracellular volume (ECV) expansion is a key feature of heart failure. CMR T1 mapping has been developed as a noninvasive technique to estimate ECV; however, the diagnostic and prognostic impacts of this technique have not been well established. A total of 473 consecutive patients referred for CMR (49.5% female, age 57.8 ± 17.1 years) without hypertrophic cardiomyopathy, cardiac amyloidosis, or Anderson-Fabry disease were studied. T1 mapping with the modified Look-Locker inversion recovery (MOLLI) sequence was used for ECV calculation (CMR-ECV). For methodological validation, 36 patients also underwent left ventricular biopsy, and ECV was quantified by TissueFAXS analysis (TissueFAXS-ECV). To assess the prognostic value of CMR-ECV, its association with hospitalization for cardiovascular reasons or cardiac death was tested in a multivariable Cox regression model. TissueFAXS-ECV was 26.3 ± 7.2% and was significantly correlated with CMR-ECV (r = 0.493, p = 0.002). Patients were followed up for 13.3 ± 9.0 months and divided into CMR-ECV tertiles for Kaplan-Meier analysis (tertiles were ≤ 25.7%, 25.8% to 28.5%, and ≥ 28.6%). Significantly higher event rates were observed in patients with higher CMR-ECV (log-rank p = 0.013). By multivariable Cox regression analysis, CMR-ECV was independently associated with outcome among imaging variables (p = 0.004) but not after adjustment for clinical parameters. CMR T1 mapping allows accurate noninvasive quantification of ECV and is independently associated with event-free survival among imaging parameters. Its prognostic value on top of established clinical risk factors warrants further investigation in long-term studies. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  16. Role of nutrient-sensing taste 1 receptor (T1R) family members in gastrointestinal chemosensing.

    PubMed

    Shirazi-Beechey, Soraya P; Daly, Kristian; Al-Rammahi, Miran; Moran, Andrew W; Bravo, David

    2014-06-01

    Luminal nutrient sensing by G-protein-coupled receptors (GPCR) expressed on the apical domain of enteroendocrine cells activates intracellular pathways leading to secretion of gut hormones that control vital physiological processes such as digestion, absorption, food intake and glucose homeostasis. The taste 1 receptor (T1R) family of GPCR consists of three members: T1R1; T1R2; T1R3. Expression of T1R1, T1R2 and T1R3 at mRNA and protein levels has been demonstrated in the intestinal tissue of various species. It has been shown that T1R2-T1R3, in association with G-protein gustducin, is expressed in intestinal K and L endocrine cells, where it acts as the intestinal glucose (sweet) sensor. A number of studies have demonstrated that activation of T1R2-T1R3 by natural sugars and artificial sweeteners leads to secretion of glucagon-like peptides 1&2 (GLP-1 and GLP-2) and glucose dependent insulinotropic peptide (GIP). GLP-1 and GIP enhance insulin secretion; GLP-2 increases intestinal growth and glucose absorption. T1R1-T1R3 combination co-expressed on the apical domain of cholecystokinin (CCK) expressing cells is a luminal sensor for a number of L-amino acids; with amino acid-activation of the receptor eliciting CCK secretion. This article focuses on the role of the gut-expressed T1R1, T1R2 and T1R3 in intestinal sweet and L-amino acid sensing. The impact of exploiting T1R2-T1R3 as a nutritional target for enhancing intestinal glucose absorption and gut structural maturity in young animals is also highlighted.

  17. Dynamics-based selective 2D 1H/1H chemical shift correlation spectroscopy under ultrafast MAS conditions

    NASA Astrophysics Data System (ADS)

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2015-05-01

    Dynamics plays important roles in determining the physical, chemical, and functional properties of a variety of chemical and biological materials. However, a material (such as a polymer) generally has mobile and rigid regions in order to have high strength and toughness at the same time. Therefore, it is difficult to measure the role of mobile phase without being affected by the rigid components. Herein, we propose a highly sensitive solid-state NMR approach that utilizes a dipolar-coupling based filter (composed of 12 equally spaced 90° RF pulses) to selectively measure the correlation of 1H chemical shifts from the mobile regions of a material. It is interesting to find that the rotor-synchronized dipolar filter strength decreases with increasing inter-pulse delay between the 90° pulses, whereas the dipolar filter strength increases with increasing inter-pulse delay under static conditions. In this study, we also demonstrate the unique advantages of proton-detection under ultrafast magic-angle-spinning conditions to enhance the spectral resolution and sensitivity for studies on small molecules as well as multi-phase polymers. Our results further demonstrate the use of finite-pulse radio-frequency driven recoupling pulse sequence to efficiently recouple weak proton-proton dipolar couplings in the dynamic regions of a molecule and to facilitate the fast acquisition of 1H/1H correlation spectrum compared to the traditional 2D NOESY (Nuclear Overhauser effect spectroscopy) experiment. We believe that the proposed approach is beneficial to study mobile components in multi-phase systems, such as block copolymers, polymer blends, nanocomposites, heterogeneous amyloid mixture of oligomers and fibers, and other materials.

  18. The pT1a and pT1b category subdivision in renal cell carcinoma: is it reflected by differences in tumour biology?

    PubMed

    Langner, Cord; Ratschek, Manfred; Rehak, Peter; Tsybrovskyy, Oleksiy; Zigeuner, Richard

    2005-02-01

    To assess systematically the possible differences in pathology between pT1a and pT1b renal cell carcinomas (RCCs), as the sixth edition of the Tumour-Nodes-Metastasis (TNM) system implemented a subdivision of category pT1 into pT1a (<4 cm) and pT1b (4-7 cm), based on clinical outcome analysis and the approach to therapy. Conventional histopathology and immunohistochemical expression of several biomarkers were analysed in 66 patients with pT1a and 29 with pT1b RCCs, using a tissue microarray technique. After 2 years of follow-up, none of the 66 patients with pT1a and three of the 29 with pT1b tumours developed progressive disease. The tumour was grade 3 in four (6%) pT1a and 11 (38%) pT1b RCCs. Immunohistochemically, pT1a RCCs were characterized by strong expression of p27 (79%), bcl-2 (67%), MUC1 (87%), insulin-like growth factor (IGF)-I (71%) and CD10 (88%), as well as moderate expression of IGF-I receptor (43%) and low expression of epidermal growth factor receptor (EGFR, 20%). During progression to category pT1b, expression of p27 significantly decreased (54%) and EGFR expression increased (38%). Moreover, membranous staining patterns of MUC1 and CD10 changed from apical to circumferential in clear cell RCCs. p53 (pT1a 23%, pT1b 28%), E-cadherin (10% and 17%), MIB-1 (1.2% and 1.5%) and Skp2 (2% and none) expression seemed to be of minor importance. This is the first study to show that the subdivision of category pT1 implemented in the latest issue of the TNM system is reflected by differences in conventional histopathology and expression of biomarkers.

  19. Magnetic resonance imaging phantoms for quality-control of myocardial T1 and ECV mapping: specific formulation, long-term stability and variation with heart rate and temperature.

    PubMed

    Vassiliou, Vassilios S; Heng, Ee Ling; Gatehouse, Peter D; Donovan, Jacqueline; Raphael, Claire E; Giri, Shivraman; Babu-Narayan, Sonya V; Gatzoulis, Michael A; Pennell, Dudley J; Prasad, Sanjay K; Firmin, David N

    2016-09-22

    Magnetic resonance imaging (MRI) phantoms are routinely used for quality assurance in MRI centres; however their long term stability for verification of myocardial T1/ extracellular volume fraction (ECV) mapping has never been investigated. Nickel-chloride agarose gel phantoms were formulated in a reproducible laboratory procedure to mimic blood and myocardial T1 and T2 values, native and late after Gadolinium administration as used in T1/ECV mapping. The phantoms were imaged weekly with an 11 heart beat MOLLI sequence for T1 and long TR spin-echo sequences for T2, in a carefully controlled reproducible manner for 12 months. There were only small relative changes seen in all the native and post gadolinium T1 values (up to 9.0 % maximal relative change in T1 values) or phantom ECV (up to 8.3 % maximal relative change of ECV, up to 2.2 % maximal absolute change in ECV) during this period. All native and post gadolinium T2 values remained stable over time with <2 % change. Temperature sensitivity testing showed MOLLI T1 values in the long T1 phantoms increasing by 23.9 ms per degree increase and short T1 phantoms increasing by 0.3 ms per degree increase. There was a small absolute increase in ECV of 0.069 % (~0.22 % relative increase in ECV) per degree increase. Variation in heart rate testing showed a 0.13 % absolute increase in ECV (~0.45 % relative increase in ECV) per 10 heart rate increase. These are the first phantoms reported in the literature modeling T1 and T2 values for blood and myocardium specifically for the T1mapping/ECV mapping application, with stability tested rigorously over a 12 month period. This work has significant implications for the utility of such phantoms in improving the accuracy of serial scans for myocardial tissue characterisation by T1 mapping methods and in multicentre work.

  20. Different functional roles of T1R subunits in the heteromeric taste receptors.

    PubMed

    Xu, Hong; Staszewski, Lena; Tang, Huixian; Adler, Elliot; Zoller, Mark; Li, Xiaodong

    2004-09-28

    The T1R receptors, a family of taste-specific class C G protein-coupled receptors, mediate mammalian sweet and umami tastes. The structure-function relationships of T1R receptors remain largely unknown. In this study, we demonstrate the different functional roles of T1R extracellular and transmembrane domains in ligand recognition and G protein coupling. Similar to other family C G protein-coupled receptors, the N-terminal Venus flytrap domain of T1R2 is required for recognizing sweeteners, such as aspartame and neotame. The G protein coupling requires the transmembrane domain of T1R2. Surprisingly, the C-terminal transmembrane domain of T1R3 is required for recognizing sweetener cyclamate and sweet taste inhibitor lactisole. Because T1R3 is the common subunit in the sweet taste receptor and the umami taste receptor, we tested the interaction of lactisole and cyclamate with the umami taste receptor. Lactisole inhibits the activity of the human T1R1/T1R3 receptor, and, as predicted, blocked the umami taste of l-glutamate in human taste tests. Cyclamate does not activate the T1R1/T1R3 receptor by itself, but potentiates the receptor's response to l-glutamate. Taken together, these findings demonstrate the different functional roles of T1R3 and T1R2 and the presence of multiple ligand binding sites on the sweet taste receptor.

  1. Different functional roles of T1R subunits in the heteromeric taste receptors

    PubMed Central

    Xu, Hong; Staszewski, Lena; Tang, Huixian; Adler, Elliot; Zoller, Mark; Li, Xiaodong

    2004-01-01

    The T1R receptors, a family of taste-specific class C G proteincoupled receptors, mediate mammalian sweet and umami tastes. The structure–function relationships of T1R receptors remain largely unknown. In this study, we demonstrate the different functional roles of T1R extracellular and transmembrane domains in ligand recognition and G protein coupling. Similar to other family C G protein-coupled receptors, the N-terminal Venus flytrap domain of T1R2 is required for recognizing sweeteners, such as aspartame and neotame. The G protein coupling requires the transmembrane domain of T1R2. Surprisingly, the C-terminal transmembrane domain of T1R3 is required for recognizing sweetener cyclamate and sweet taste inhibitor lactisole. Because T1R3 is the common subunit in the sweet taste receptor and the umami taste receptor, we tested the interaction of lactisole and cyclamate with the umami taste receptor. Lactisole inhibits the activity of the human T1R1/T1R3 receptor, and, as predicted, blocked the umami taste of l-glutamate in human taste tests. Cyclamate does not activate the T1R1/T1R3 receptor by itself, but potentiates the receptor's response to l-glutamate. Taken together, these findings demonstrate the different functional roles of T1R3 and T1R2 and the presence of multiple ligand binding sites on the sweet taste receptor. PMID:15353592

  2. Crystal structure of 1H,1'H-[2,2'-biimid-azol]-3-ium hydrogen tartrate hemi-hydrate.

    PubMed

    Gao, Xiao-Li; Bian, Li-Fang; Guo, Shao-Wei

    2014-11-01

    In the crystal of the title hydrated salt, C6H7N4 (+)·C4H5O6 (-)·0.5H2O, the bi-imidazole monocation, 1H,1'H-[2,2'-biimidazol]-3-ium, is hydrogen bonded, via N-H⋯O, O-H⋯O and O-H⋯N hydrogen bonds, to the hydrogen tartrate anion and the water mol-ecule, which is located on a twofold rotation axis, forming sheets parallel to (001). The sheets are linked via C-H⋯O hydrogen bonds, forming a three-dimensional structure. There are also C=O⋯π inter-actions present [O⋯π distances are 3.00 (9) and 3.21 (7) Å], involving the carbonyl O atoms and the imidazolium ring, which may help to consolidate the structure. In the cation, the dihedral angle between the rings is 11.6 (2)°.

  3. The evaluation of non-ischemic dilated cardiomyopathy with T1 mapping and ECV methods using 3T cardiac MRI.

    PubMed

    Görmeli, Cemile Ayşe; Özdemir, Zeynep Maraş; Kahraman, Ayşegül Sağır; Yağmur, Jülide; Özdemir, Ramazan; Çolak, Cemil

    2017-02-01

    The aim of this study was to examine the correlation between ventricular function and the extracellular volume fraction (ECV) in patients with non-ischemic dilated cardiomyopathy (NIDCM) using 3.0 T magnetic resonance imaging (MRI). We also hypothesized that native T1 and ECV values would be increased in patients with NIDCM, independent of the left ventricular ejection fraction (LVEF). The findings of our study could lead to further studies of the follow-up protocols. In total, 53 consecutive dilated cardiomyopathy patients who had undergone cardiac MRI were functionally evaluated and underwent tissue characterization. The mean native T1 value was 1235 ± 10 ms, and the mean ECV value was 35.4 ± 2.7% in the myocardia. The LVEF values ranged from 29 to 44%. No significant correlations were observed between functional analysis measurements and native T1 or ECV values. Our results showed that myocardial fibrosis is unrelated to cardiac functional findings in NIDCM patients. Therefore, we propose that these patients should be evaluated using MRI and tissue characterization techniques, in addition to cardiac functional analysis.

  4. High-resolution myocardial T1 mapping using single-shot inversion recovery fast low-angle shot MRI with radial undersampling and iterative reconstruction

    PubMed Central

    Joseph, Arun A; Kalentev, Oleksandr; Merboldt, Klaus-Dietmar; Voit, Dirk; Roeloffs, Volkert B; van Zalk, Maaike; Frahm, Jens

    2016-01-01

    Objective: To develop a novel method for rapid myocardial T1 mapping at high spatial resolution. Methods: The proposed strategy represents a single-shot inversion recovery experiment triggered to early diastole during a brief breath-hold. The measurement combines an adiabatic inversion pulse with a real-time readout by highly undersampled radial FLASH, iterative image reconstruction and T1 fitting with automatic deletion of systolic frames. The method was implemented on a 3-T MRI system using a graphics processing unit-equipped bypass computer for online application. Validations employed a T1 reference phantom including analyses at simulated heart rates from 40 to 100 beats per minute. In vivo applications involved myocardial T1 mapping in short-axis views of healthy young volunteers. Results: At 1-mm in-plane resolution and 6-mm section thickness, the inversion recovery measurement could be shortened to 3 s without compromising T1 quantitation. Phantom studies demonstrated T1 accuracy and high precision for values ranging from 300 to 1500 ms and up to a heart rate of 100 beats per minute. Similar results were obtained in vivo yielding septal T1 values of 1246 ± 24 ms (base), 1256 ± 33 ms (mid-ventricular) and 1288 ± 30 ms (apex), respectively (mean ± standard deviation, n = 6). Conclusion: Diastolic myocardial T1 mapping with use of single-shot inversion recovery FLASH offers high spatial resolution, T1 accuracy and precision, and practical robustness and speed. Advances in knowledge: The proposed method will be beneficial for clinical applications relying on native and post-contrast T1 quantitation. PMID:27759423

  5. Analysis of the Precision of Variable Flip Angle T1 Mapping with Emphasis on the Noise Propagated from RF Transmit Field Maps.

    PubMed

    Lee, Yoojin; Callaghan, Martina F; Nagy, Zoltan

    2017-01-01

    In magnetic resonance imaging, precise measurements of longitudinal relaxation time (T1) is crucial to acquire useful information that is applicable to numerous clinical and neuroscience applications. In this work, we investigated the precision of T1 relaxation time as measured using the variable flip angle method with emphasis on the noise propagated from radiofrequency transmit field ([Formula: see text]) measurements. The analytical solution for T1 precision was derived by standard error propagation methods incorporating the noise from the three input sources: two spoiled gradient echo (SPGR) images and a [Formula: see text] map. Repeated in vivo experiments were performed to estimate the total variance in T1 maps and we compared these experimentally obtained values with the theoretical predictions to validate the established theoretical framework. Both the analytical and experimental results showed that variance in the [Formula: see text] map propagated comparable noise levels into the T1 maps as either of the two SPGR images. Improving precision of the [Formula: see text] measurements significantly reduced the variance in the estimated T1 map. The variance estimated from the repeatedly measured in vivoT1 maps agreed well with the theoretically-calculated variance in T1 estimates, thus validating the analytical framework for realistic in vivo experiments. We concluded that for T1 mapping experiments, the error propagated from the [Formula: see text] map must be considered. Optimizing the SPGR signals while neglecting to improve the precision of the [Formula: see text] map may result in grossly overestimating the precision of the estimated T1 values.

  6. One dimensional 1H, 2H and 3H

    NASA Astrophysics Data System (ADS)

    Vidal, A. J.; Astrakharchik, G. E.; Vranješ Markić, L.; Boronat, J.

    2016-05-01

    The ground-state properties of one-dimensional electron-spin-polarized hydrogen 1H, deuterium 2H, and tritium 3H are obtained by means of quantum Monte Carlo methods. The equations of state of the three isotopes are calculated for a wide range of linear densities. The pair correlation function and the static structure factor are obtained and interpreted within the framework of the Luttinger liquid theory. We report the density dependence of the Luttinger parameter and use it to identify different physical regimes: Bogoliubov Bose gas, super-Tonks-Girardeau gas, and quasi-crystal regimes for bosons; repulsive, attractive Fermi gas, and quasi-crystal regimes for fermions. We find that the tritium isotope is the one with the richest behavior. Our results show unambiguously the relevant role of the isotope mass in the properties of this quantum system.

  7. Activation of the umami taste receptor (T1R1/T1R3) initiates the peristaltic reflex and pellet propulsion in the distal colon.

    PubMed

    Kendig, Derek M; Hurst, Norman R; Bradley, Zachary L; Mahavadi, Sunila; Kuemmerle, John F; Lyall, Vijay; DeSimone, John; Murthy, Karnam S; Grider, John R

    2014-12-01

    Intraluminal nutrients in the gut affect the peristaltic reflex, although the mechanism is not well defined. Recent evidence supports the presence of taste receptors and their signaling components in enteroendocrine cells, although their function is unclear. This study aimed to determine if nutrients modify colonic motility through activation of taste receptors. Colonic sections were immunostained for the umami taste receptor T1R1/T1R3, which mediates the response to umami ligands, such as monosodium glutamate (MSG), in taste cells. Ascending contraction, descending relaxation, and calcitonin gene-related peptide release were measured in three-chamber flat-sheet preparations of rat colon in response to MSG alone or with inosine 5'-monophosphate (IMP). Velocity of artificial fecal pellet propulsion was measured by video recording in guinea pig distal colon. T1R1/T1R3 receptors were present in enteroendocrine cells of colonic sections from human, rat, mouse, and guinea pig. MSG initiated ascending contraction and descending relaxation components of the peristaltic reflex and calcitonin gene-related peptide release in flat-sheet preparations. IMP augmented the MSG-induced effects, suggesting activation of T1R1/T1R3 receptors. In T1R1(-/-) mice, mucosal stroking, but not MSG, elicited a peristaltic reflex. Intraluminal perfusion of MSG enhanced the velocity of artificial fecal pellet propulsion, which was also augmented by IMP. Propulsion was also increased by l-cysteine, but not l-tryptophan, supporting a role of T1R1/T1R3 receptors. We conclude that T1R1/T1R3 activation by luminal MSG or l-cysteine elicits a peristaltic reflex and CGRP release and increases the velocity of pellet propulsion in distal colon. This mechanism may explain how nutrients regulate colonic propulsion.

  8. The interplay of T1- and T2-relaxation on T1-weighted MRI of hMSCs induced by Gd-DOTA-peptides.

    PubMed

    Cao, Limin; Li, Binbin; Yi, Peiwei; Zhang, Hailu; Dai, Jianwu; Tan, Bo; Deng, Zongwu

    2014-04-01

    Three Gd-DOTA-peptide complexes with different peptide sequence are synthesized and used as T1 contrast agent to label human mesenchymal stem cells (hMSCs) for magnetic resonance imaging study. The peptides include a universal cell penetrating peptide TAT, a linear MSC-specific peptide EM7, and a cyclic MSC-specific peptide CC9. A significant difference in labeling efficacy is observed between the Gd-DOTA-peptides as well as a control Dotarem. All Gd-DOTA-peptides as well as Dotarem induce significant increase in T1 relaxation rate which is in favor of T1-weighted MR imaging. Gd-DOTA-CC9 yields the maximum labeling efficacy but poor T1 contrast enhancement. Gd-DOTA-EM7 yields the minimum labeling efficacy but better T1 contrast enhancement. Gd-DOTA-TAT yields a similar labeling efficacy as Gd-DOTA-CC9 and similar T1 contrast enhancement as Gd-DOTA-EM7. The underlying mechanism that governs T1 contrast enhancement effect is discussed. Our results suggest that T1 contrast enhancement induced by Gd-DOTA-peptides depends not only on the introduced cellular Gd content, but more importantly on the effect that Gd-DOTA-peptides exert on the T1-relaxation and T2-relaxation processes/rates. Both T1 and particularly T2 relaxation rate have to be taken into account to interpret T1 contrast enhancement. In addition, the interpretation has to be based on cellular instead of aqueous longitudinal and transverse relaxivities of Gd-DOTA-peptides.

  9. Prognostic Significance of Remote Myocardium Alterations Assessed by Quantitative Noncontrast T1 Mapping in ST-Segment Elevation Myocardial Infarction.

    PubMed

    Reinstadler, Sebastian J; Stiermaier, Thomas; Liebetrau, Johanna; Fuernau, Georg; Eitel, Charlotte; de Waha, Suzanne; Desch, Steffen; Reil, Jan-Christian; Pöss, Janine; Metzler, Bernhard; Lücke, Christian; Gutberlet, Matthias; Schuler, Gerhard; Thiele, Holger; Eitel, Ingo

    2017-06-09

    This study assessed the prognostic significance of remote zone native T1 alterations for the prediction of clinical events in a population with ST-segment elevation myocardial infarction (STEMI) who were treated by primary percutaneous coronary intervention (PPCI) and compared it with conventional markers of infarct severity. The exact role and incremental prognostic relevance of remote myocardium native T1 mapping alterations assessed by cardiac magnetic resonance (CMR) after STEMI remains unclear. We included 255 consecutive patients with STEMI who were reperfused within 12 h after symptom onset. CMR core laboratory analysis was performed to assess left ventricular (LV) function, standard infarct characteristics, and native T1 values of the remote, noninfarcted myocardium. The primary endpoint was a composite of death, reinfarction, and new congestive heart failure within 6 months (major adverse cardiac events [MACE]). Patients with increased remote zone native T1 values (>1,129 ms) had significantly larger infarcts (p = 0.012), less myocardial salvage (p = 0.002), and more pronounced LV dysfunction (p = 0.011). In multivariable analysis, remote zone native T1 was independently associated with MACE after adjusting for clinical risk factors (p = 0.001) or other CMR variables (p = 0.007). In C-statistics, native T1 of remote myocardium provided incremental prognostic information beyond clinical risk factors, LV ejection fraction, and other markers of infarct severity (all p < 0.05). The addition of remote zone native T1 to a model of prognostic CMR parameters (ejection fraction, infarct size, and myocardial salvage index) led to net reclassification improvement of 0.82 (95% confidence interval: 0.46 to 1.17; p < 0.001) and to an integrated discrimination improvement of 0.07 (95% confidence interval: 0.02 to 0.13; p = 0.01). In STEMI patients treated by PPCI, evaluation of remote zone alterations by quantitative noncontrast T1 mapping provided independent

  10. Europium-engineered iron oxide nanocubes with high T1 and T2 contrast abilities for MRI in living subjects.

    PubMed

    Yang, Lijiao; Zhou, Zijian; Liu, Hanyu; Wu, Changqiang; Zhang, Hui; Huang, Guoming; Ai, Hua; Gao, Jinhao

    2015-04-21

    Magnetic resonance imaging (MRI) contrast agents with both positive (T1) and negative (T2) contrast abilities are needed in clinical diagnosis for fault-free accurate detection of lesions. We report a facile synthesis of europium-engineered iron oxide (EuIO) nanocubes as T1 and T2 contrast agents for MRI in living subjects. The Eu(iii) oxide-embedded iron oxide nanoparticles significantly increase the T1 relaxivity with an enhanced positive contrast effect. EuIO nanocubes with 14 nm in diameter showed a high r1 value of 36.8 mM(-1) s(-1) with respect to total metal ions (Fe + Eu), which is about 3 times higher than that of Fe3O4 nanoparticles with similar size. Moreover, both r1 and r2 values of EuIO nanocubes can be tuned by varying their sizes and Eu doping ratios. After citrate coating, EuIO nanocubes can provide enhanced T1 and T2 contrast effects in small animals, particularly in the cardiac and liver regions. This work may provide an insightful strategy to design MRI contrast agents with both positive and negative contrast abilities for biomedical applications.

  11. Simultaneous Variable Flip Angle – Actual Flip Angle Imaging (VAFI) Method for Improved Accuracy and Precision of Three-dimensional T1 and B1 Measurements

    PubMed Central

    Hurley, Samuel A.; Yarnykh, Vasily L.; Johnson, Kevin M.; Field, Aaron S.; Alexander, Andrew L.; Samsonov, Alexey A.

    2011-01-01

    A new time-efficient and accurate technique for simultaneous mapping of T1 and B1 is proposed based on a combination of the Actual Flip angle Imaging (AFI) and Variable Flip Angle (VFA) methods: VAFI. VAFI utilizes a single AFI and one or more spoiled gradient-echo (SPGR) acquisitions with a simultaneous non-linear fitting procedure to yield accurate T1/B1 maps. The advantage of VAFI is high accuracy at either short T1 times or long TR in the AFI sequence. Simulations show this method is accurate to 0.03% in FA and 0.07% in T1 for TR/T1 times over the range of 0.01 to 0.45. We show for the case of brain imaging that it is sufficient to use only one small flip angle SPGR acquisition, which results in reduced spoiling requirements and a significant scan time reduction compared to the original VFA. In-vivo validation yielded high-quality 3D T1 maps and T1 measurements within 10% of previously published values, and within a clinically acceptable scan time. The VAFI method will increase the accuracy and clinical feasibility of many quantitative MRI methods requiring T1/B1 mapping such as DCE perfusion and quantitative MTI. PMID:22139819

  12. Significant correlation between openness personality in normal subjects and brain myelin mapping with T1/T2-weighted MR imaging.

    PubMed

    Yasuno, Fumihiko; Kudo, Takashi; Yamamoto, Akihide; Matsuoka, Kiwamu; Takahashi, Masato; Iida, Hidehiro; Ihara, Masafumi; Nagatsuka, Kazuyuki; Kishimoto, Toshifumi

    2017-09-01

    The objective of this study was to examine the relationship between the myelination and the psychological trait of openness to experience in young cognitively normal volunteers using regional T1-weighted (T1w)/T2w ratios on magnetic resonance imaging (MRI). It was hypothesized that axonal myelination would be related to openness, thus linking trait creativity and mental illness. We recruited 37 healthy subjects and administered the NEO Five-Factor Inventory to assess personality factors. Regional T1w/T2w MRI values were computed as surrogate indicators of myelination status and correlations between T1w/T2w values and various personality factors (e.g., trait of openness) were calculated with a voxel-based analysis using statistical parametric mapping. Significant negative correlations were identified between the trait of openness and T1w/T2w values in the medial frontal cortex, anterior cingulate cortex, posterior cingulate cortex, and posterior insula/adjacent putamen. These relationships remained significant even after adjusting for age, sex, and education as covariates. There were no significant correlations between other personality factors and regional volumes. Individual differences in openness may be associated with variations in intra-cortical myelination, specifically in the imaginative network of the brain including the midline core 'hubs' of the default mode network (anterior cingulate/medial frontal cortex and posterior cingulate cortex) and regions related to motivational state (posterior insula and adjacent putamen). Signal interference related to decreased myelination may facilitate flexible imagination and the trait of openness. Our findings assist in understanding the relationship between myelination and openness, as a link between creativity and mental illness.

  13. Arrangement and mobility of water in vermiculite hydrates followed by 1H NMR spectroscopy.

    PubMed

    Sanz, J; Herrero, C P; Serratosa, J M

    2006-04-20

    The arrangement of water molecules in one- and two-layer hydrates of high-charged vermiculites, saturated with alkaline (Li(+), Na(+)) and alkali-earth (Mg(2+), Ca(2+), Ba(2+)) cations, has been analyzed with (1)H NMR spectroscopy. Two different orientations for water molecules have been found, depending on the hydration state and the sites occupied by interlayer cations. As the amount of water increases, hydrogen bond interactions between water molecules increase at expenses of water-silicate interactions. This interaction favors water mobility in vermiculites. A comparison of the temperature dependence of relaxation times T(1) and T(2) for one and two-layer hydrates of Na-vermiculite shows that the rotations of water molecules around C(2)-axes and that of cation hydration shells around the c-axis is favored in the two-layer hydrate. In both hydrates, the anisotropic diffusion of water takes place at room temperature, preserving the orientation of water molecules relative to the silicate layers. Information obtained by NMR spectroscopy is compatible with that deduced by infrared spectroscopy and with structural studies carried out with X-ray and neutron diffraction techniques on single-crystals of vermiculite.

  14. Taurine - a possible fingerprint biomarker in non-muscle invasive bladder cancer: A pilot study by 1H NMR spectroscopy.

    PubMed

    Srivastava, Shatakshi; Roy, Raja; Singh, Sudhir; Kumar, Praveen; Dalela, Diwakar; Sankhwar, Satya N; Goel, Apul; Sonkar, Abhinav A

    2010-01-01

    Urinary bladder cancer is a major epidemiological problem that continues to grow each year. It opens avenues for investigative research for the identification of new disease markers and diagnostic techniques. In this pilot study, utility of non-invasive (1)H NMR spectroscopy has been evaluated for probing the metabolic perturbations occurring in non-muscle invasive urinary bladder cancer. (1)H NMR spectra of urine of bladder cancer patients and controls (healthy and urinary tract infection/bladder stone) (n = 103) were acquired at 400MHz. The non-overlapping resonances of citrate, dimethylamine, phenylalanine, taurine and hippurate were first identified and then quantitated by (1)H NMR spectra, with respect to an external reference sodium-3-trimethylsilylpropionate (TSP). The concentrations of these metabolites were then statistically analyzed. The cancer patients showed significant (p < 0.05) variations in concentration of hippurate and citrate as compared with healthy controls and benign controls. The significant elevation in concentration of taurine was observed in urine of bladder cancer patients, which was below the sensitivity limit of 400MHz in control cases. However, stages Ta, T1 and carcinoma in situ (CIS) cannot be differentiated on the basis of altered metabolite indices but their composition may reflect the biochemical alterations in metabolism of cancer cells.

  15. An improved prognostic model for stage T1a and T1b prostate cancer by assessments of cancer extent

    PubMed Central

    Rajab, Ramzi; Fisher, Gabrielle; Kattan, Michael W; Foster, Christopher S; Møller, Henrik; Oliver, Tim; Reuter, Victor; Scardino, Peter T; Cuzick, Jack; Berney, Daniel M

    2013-01-01

    Treatment decisions on prostate cancer diagnosed by trans-urethral resection (TURP) of the prostate are difficult. The current TNM staging system for pT1 prostate cancer has not been re-evaluated for 25 years. Our objective was to optimise the predictive power of tumor extent measurements in TURP of the prostate specimens. A total of 914 patients diagnosed by TURP of the prostate between 1990 and 1996, managed conservatively were identified. The clinical end point was death from prostate cancer. Diagnostic serum prostate-specific antigen (PSA) and contemporary Gleason grading was available. Cancer extent was measured by the percentage of chips infiltrated by cancer. Death rates were compared by univariate and multivariate proportional hazards models, including baseline PSA and Gleason score. The percentage of positive chips was highly predictive of prostate cancer death when assessed as a continuous variable or as a grouped variable on the basis of and including the quintiles, quartiles, tertiles and median groups. In the univariate model, the most informative variable was a four group-split (≤ 10%, >10–25%, > 25–75% and > 75%); (HR = 2.08, 95% CI = 1.8–2.4, P < 0.0001). The same was true in a multivariate model (ΔX2 (1 d.f.) = 15.0, P = 0.0001). The current cutoff used by TNM (< = 5%) was sub-optimal (ΔX2 (1 d.f.) = 4.8, P = 0.023). The current TNM staging results in substantial loss of information. Staging by a four-group subdivision would substantially improve prognostication in patients with early stage disease and also may help to refine management decisions in patients who would do well with conservative treatments. PMID:20834240

  16. Decoding of exon splicing patterns in the human RUNX1-RUNX1T1 fusion gene.

    PubMed

    Grinev, Vasily V; Migas, Alexandr A; Kirsanava, Aksana D; Mishkova, Olga A; Siomava, Natalia; Ramanouskaya, Tatiana V; Vaitsiankova, Alina V; Ilyushonak, Ilia M; Nazarov, Petr V; Vallar, Laurent; Aleinikova, Olga V

    2015-11-01

    The t(8;21) translocation is the most widespread genetic defect found in human acute myeloid leukemia. This translocation results in the RUNX1-RUNX1T1 fusion gene that produces a wide variety of alternative transcripts and influences the course of the disease. The rules of combinatorics and splicing of exons in the RUNX1-RUNX1T1 transcripts are not known. To address this issue, we developed an exon graph model of the fusion gene organization and evaluated its local exon combinatorics by the exon combinatorial index (ECI). Here we show that the local exon combinatorics of the RUNX1-RUNX1T1 gene follows a power-law behavior and (i) the vast majority of exons has a low ECI, (ii) only a small part is represented by "exons-hubs" of splicing with very high ECI values, and (iii) it is scale-free and very sensitive to targeted skipping of "exons-hubs". Stochasticity of the splicing machinery and preferred usage of exons in alternative splicing can explain such behavior of the system. Stochasticity may explain up to 12% of the ECI variance and results in a number of non-coding and unproductive transcripts that can be considered as a noise. Half-life of these transcripts is increased due to the deregulation of some key genes of the nonsense-mediated decay system in leukemia cells. On the other hand, preferred usage of exons may explain up to 75% of the ECI variability. Our analysis revealed a set of splicing-related cis-regulatory motifs that can explain "attractiveness" of exons in alternative splicing but only when they are considered together. Cis-regulatory motifs are guides for splicing trans-factors and we observed a leukemia-specific profile of expression of the splicing genes in t(8;21)-positive blasts. Altogether, our results show that alternative splicing of the RUNX1-RUNX1T1 transcripts follows strict rules and that the power-law component of the fusion gene organization confers a high flexibility to this process. Copyright © 2015 Elsevier Ltd. All rights

  17. The data processing and analysis for the CE-5T1 GNSS experiment

    NASA Astrophysics Data System (ADS)

    Liu, Huicui; Cao, Jianfeng; Cheng, Xiao; Peng, Jing; Tang, Geshi

    2017-02-01

    In this paper the performance of a high sensitivity GPS/GLONASS receiver mounted on CE-5T1 Service Module is studied and the data received on the first Earth-lunar transfer orbit is processed and analyzed. At least four GLONASS satellites are visible for 46% of the data span while for 98% of the data span at least four GPS satellites are visible. GLONASS serves as a necessary supplement to GPS in real time positioning whenever less than four GPS satellites are tracked, and helps to optimize the observation geometry by reducing the Position Dilution of Precision (PDOP) values by up to 77%. However, noisier GLONASS pseudorange data should be properly weighted in order not to deteriorate the positioning accuracy. Studies indicate that when the inverse square of the pseudorange measurement error of each satellite is applied as the weight value, single point positioning (SPP) accuracy improves from 57.7 m (RMS) with GPS data alone to 44.6 m (RMS) with the addition of GLONASS data. Transmitter antenna Equivalent Isotropic Radiated Power (EIRP)s of all the four blocks of GPS satellites as well as GLONASS satellites are derived from the received C/N0 data and show significant variance in sidelobe power patterns. In general, the EIRP patterns of GPS Block IIR-M and GLONASS satellite antennas have a comparatively flat power level of around 10 dB W within the off-boresight angle range of 30-80° and roll off at the off-boresight angle of about 80°, offering deep space applications greater benefits than the other three blocks of GPS satellites. In addition, an interesting close encounter happens between CE-5T1 spacecraft and GLONASS satellite R06. Investigations indicate that the PDOP value increases up to 1.4 times and the SPP accuracy deteriorates by more than 142% if satellite R06 is excluded in the positioning computation.

  18. Gurmarin sensitivity of sweet taste responses is associated with co-expression patterns of T1r2, T1r3, and gustducin.

    PubMed

    Shigemura, Noriatsu; Nakao, Kazuko; Yasuo, Toshiaki; Murata, Yoshihiro; Yasumatsu, Keiko; Nakashima, Akihiko; Katsukawa, Hideo; Sako, Noritaka; Ninomiya, Yuzo

    2008-03-07

    Gurmarin (Gur) is a peptide that selectively suppresses sweet taste responses in rodents. The inhibitory effect of Gur differs among tongue regions and mouse strains. Recent studies demonstrated that co-expression levels of genes controlling sweet receptors (T1r2/T1r3 heterodimer) versus Galpha-protein, gustducin, are much lower in Gur-insensitive posterior circumvallate papillae than in Gur-sensitive anterior fungiform papillae. Here, we investigated the potential link of Gur-sensitivity with the co-expression for T1r2/T1r3 receptors and gustducin by comparing those of taste tissues of Gur-sensitive (B6, dpa congenic strains) and Gur-weakly-sensitive (BALB) strains. The results indicated that co-expression ratios among T1r2, T1r3, and gustducin in the fungiform papillae were significantly lower in Gur-weakly-sensitive BALB mice than in Gur-sensitive B6 and dpa congenic mice. This linkage between Gur-sensitivity and co-expression for T1r2/T1r3 receptors versus gustducin suggests that gustducin may be a key molecule involved in the pathway for Gur-sensitive sweet responses.

  19. Multi-parametric MR assessment of T(1) black holes in multiple sclerosis : evidence that myelin loss is not greater in hypointense versus isointense T(1) lesions.

    PubMed

    Vavasour, I M; Li, D K B; Laule, C; Traboulsee, A L; Moore, G R W; Mackay, A L

    2007-12-01

    Chronic T(1) hypointense lesions in multiple sclerosis (MS) are areas of severe tissue destruction. The purpose of this study was to compare total water content (WC),myelin water content (MWC), magnetization transfer ratio (MTR), T(1) relaxation time (T(1)), mean T(2) relaxation time (GMT(2)) between stable MS lesions that are hypointense and isointense on T(1)-weighted images. Six MS patients were scanned five times over one year. WC, MWC, MTR, T(1) and GMT(2) were calculated for 15 isointense and 15 hypointense chronically stable T(1) lesions, as well as contralateral normal appearing white matter (NAWM). All MR measurements from both iso- and hypointense stable lesion types were significantly different from NAWM. WC, T(1) and GMT(2) were significantly higher and MTR significantly lower in hypointense T(1) lesions compared to isointense lesions. MWC was not significantly different between iso- and hypointense lesions. This work suggests that myelin loss occurs equally in both the chronic isointense and hypointense lesions but hypointense lesions are distinguished by increased extracellular water.

  20. Taste information derived from T1R-expressing taste cells in mice.

    PubMed

    Yoshida, Ryusuke; Ninomiya, Yuzo

    2016-03-01

    The taste system of animals is used to detect valuable nutrients and harmful compounds in foods. In humans and mice, sweet, bitter, salty, sour and umami tastes are considered the five basic taste qualities. Sweet and umami tastes are mediated by G-protein-coupled receptors, belonging to the T1R (taste receptor type 1) family. This family consists of three members (T1R1, T1R2 and T1R3). They function as sweet or umami taste receptors by forming heterodimeric complexes, T1R1+T1R3 (umami) or T1R2+T1R3 (sweet). Receptors for each of the basic tastes are thought to be expressed exclusively in taste bud cells. Sweet (T1R2+T1R3-expressing) taste cells were thought to be segregated from umami (T1R1+T1R3-expressing) taste cells in taste buds. However, recent studies have revealed that a significant portion of taste cells in mice expressed all T1R subunits and responded to both sweet and umami compounds. This suggests that sweet and umami taste cells may not be segregated. Mice are able to discriminate between sweet and umami tastes, and both tastes contribute to behavioural preferences for sweet or umami compounds. There is growing evidence that T1R3 is also involved in behavioural avoidance of calcium tastes in mice, which implies that there may be a further population of T1R-expressing taste cells that mediate aversion to calcium taste. Therefore the simple view of detection and segregation of sweet and umami tastes by T1R-expressing taste cells, in mice, is now open to re-examination. © 2016 Authors; published by Portland Press Limited.

  1. Relationship between the Carotid Plaque T1 Relaxation Time and the Plaque-to-Muscle Signal Intensity Ratio on Black-Blood Magnetic Resonance Imaging Scans.

    PubMed

    Eto, Ayumu; Kinoshita, Yoshimasa; Matsumoto, Yoshihisa; Kiyomi, Fumiaki; Iko, Minoru; Nii, Kouhei; Tsutsumi, Masanori; Sakamoto, Kimiya; Aikawa, Hiroshi; Kazekawa, Kiyoshi

    2016-11-01

    Black-blood magnetic resonance imaging (BB-MRI) is useful for the characterization and assessment of carotid artery plaques. The plaque-to-muscle signal intensity (SI) ratio (plaque/muscle ratio [PMR]) is used widely to evaluate plaques. However, the correlation between the PMR and the T1 relaxation time needs to be determined. We measured the T1 relaxation time of carotid plaques using T1 mapping and compared the results with the PMR on BB-MRI scans. Between April 2014 and July 2015, 20 patients with carotid artery stenosis were treated by carotid artery stenting. All patients underwent preoperative magnetic resonance plaque imaging. The ratio of the plaque SI to the sternocleidomastoid muscle was calculated on T1-weighted BB-MRI scans. T1 mapping was performed in the region where the vessel was narrowest using the inversion recovery technique. The T1 relaxation time was recorded to determine whether there was a correlation with the PMR. The plaque T1 value was 577.3 ± 143.2 milliseconds; the PMR value obtained on BB-MRI scans was 1.23 ± .27. There was a statistically significant decrease in the T1 value as the PMR increased (P < .0001). As the T1 relaxation time was well correlated with the PMR on BB-MRI scans, the evaluation of vulnerable plaques using the PMR was reliable and convenient. Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  2. The Culture of Pediococcus pentosaceus T1 Inhibits 
Listeria Proliferation in Salmon Fillets and Controls Maturation of Kimchi

    PubMed Central

    Jang, Seongho; Lee, Dongyun; Jang, Il Sang; Choi, Hyeon-Son

    2015-01-01

    Summary The objective of this study is to evaluate the antilisterial effect of Pediococcus pentosaceus T1, which was isolated from kimchi, and to assess its potential for extending the shelf life of salmon and kimchi. Pediococcus pentosaceus T1 culture effectively inhibited proliferation of Listeria monocytogenes in a dose-dependent manner in a salmon-based medium. Antilisterial effect of the culture was stronger than that of nisin, an antibacterial peptide, as evidenced by lower minimum inhibitory concentration value (20 mg/mL) compared to nisin (over 20 mg/mL). P. pentosaceus T1 culture also effectively inhibited the growth of Listeria in salmon fillet. In particular, the culture (6 g per 100 mL) showed a stronger inhibitory effect than sodium hypochlorite (0.2 mg/mL), a disinfectant used in food processing. In kimchi fermentation, the treatment with P. pentosaceus T1 culture suppressed changes of acidity and pH during maturation. The inhibitory effect of the culture on kimchi lactic acid bacteria, which include Leuconostoc mesenteroides and Lactobacillus sakei, led to a drastic decrease in maturation rates of kimchi. Moreover, sensory test on kimchi treated with P. pentosaceus T1 showed that the culture improved overall acceptability of kimchi, which can be observed in higher scores of sourness, texture, off-flavour and mouthfeel compared with untreated kimchi. The results of this study suggest that kimchi-derived P. pentosaceus T1 could be a potential antilisterial agent in fish products as well as a starter to control overmaturation of kimchi. PMID:27904329

  3. The Culture of Pediococcus pentosaceus T1 Inhibits 
Listeria Proliferation in Salmon Fillets and Controls Maturation of Kimchi.

    PubMed

    Jang, Seongho; Lee, Dongyun; Jang, Il Sang; Choi, Hyeon-Son; Suh, Hyung Joo

    2015-03-01

    The objective of this study is to evaluate the antilisterial effect of Pediococcus pentosaceus T1, which was isolated from kimchi, and to assess its potential for extending the shelf life of salmon and kimchi. Pediococcus pentosaceus T1 culture effectively inhibited proliferation of Listeria monocytogenes in a dose-dependent manner in a salmon-based medium. Antilisterial effect of the culture was stronger than that of nisin, an antibacterial peptide, as evidenced by lower minimum inhibitory concentration value (20 mg/mL) compared to nisin (over 20 mg/mL). P. pentosaceus T1 culture also effectively inhibited the growth of Listeria in salmon fillet. In particular, the culture (6 g per 100 mL) showed a stronger inhibitory effect than sodium hypochlorite (0.2 mg/mL), a disinfectant used in food processing. In kimchi fermentation, the treatment with P. pentosaceus T1 culture suppressed changes of acidity and pH during maturation. The inhibitory effect of the culture on kimchi lactic acid bacteria, which include Leuconostoc mesenteroides and Lactobacillus sakei, led to a drastic decrease in maturation rates of kimchi. Moreover, sensory test on kimchi treated with P. pentosaceus T1 showed that the culture improved overall acceptability of kimchi, which can be observed in higher scores of sourness, texture, off-flavour and mouthfeel compared with untreated kimchi. The results of this study suggest that kimchi-derived P. pentosaceus T1 could be a potential antilisterial agent in fish products as well as a starter to control overmaturation of kimchi.

  4. T1 Relaxation Rate (R1) Indicates Nonlinear Mn Accumulation in Brain Tissue of Welders With Low-Level Exposure

    PubMed Central

    Lee, Eun-Young; Flynn, Michael R.; Du, Guangwei; Lewis, Mechelle M.; Fry, Rebecca; Herring, Amy H.; Van Buren, Eric; Van Buren, Scott; Smeester, Lisa; Kong, Lan; Yang, Qing; Mailman, Richard B.; Huang, Xuemei

    2015-01-01

    Although the essential element manganese (Mn) is neurotoxic at high doses, the effects of lower exposure are unclear. MRI T1-weighted (TIW) imaging has been used to estimate brain Mn exposure via the pallidal index (PI), defined as the T1W intensity ratio in the globus pallidus (GP) versus frontal white matter (FWM). PI may not, however, be sensitive to Mn in GP because Mn also may accumulate in FWM. This study explored: (1) whether T1 relaxation rate (R1) could quantify brain Mn accumulation more sensitively; and (2) the dose-response relationship between estimated Mn exposure and T1 relaxation rate (R1). Thirty-five active welders and 30 controls were studied. Occupational questionnaires were used to estimate hours welding in the past 90 days (HrsW) and lifetime measures of Mn exposure. T1W imaging and T1-measurement were utilized to generate PI and R1 values in brain regions of interest (ROIs). PI did not show a significant association with any measure of Mn and/or welding-related exposure. Conversely, in several ROIs, R1 showed a nonlinear relationship to HrsW, with R1 signal increasing only after a critical exposure was reached. The GP had the greatest rate of Mn accumulation. Welders with higher exposure showed significantly higher R1 compared either with controls or with welders with lower exposure. Our data are additional evidence that Mn accumulation can be assessed more sensitively by R1 than by PI. Moreover, the nonlinear relationship between welding exposure and Mn brain accumulation should be considered in future studies and policies. PMID:25953701

  5. 1H NMR investigation of self-association of vanillin in aqueous solution

    NASA Astrophysics Data System (ADS)

    Bogdan, Mircea; Floare, Calin G.; Pîrnau, Adrian

    2009-08-01

    A self-association of vanillin have been studied by 1H NMR spectroscopy using the analysis of proton chemical shifts changes in aqueous solution as a function of concentration. The experimental results have been analysed using indefinite non-cooperative and cooperative models of molecular self-association, enabling the determination of equilibrium constants, parameters of cooperativity and the limiting values of vanillin proton chemical shifts in the complex. It was found that the dimer formation creates energetically favourable conditions for subsequent molecular association.

  6. A possible detection of Jupiter's northern auroral S1(1) H2 quadrupole line emission

    NASA Technical Reports Server (NTRS)

    Trafton, L.; Carr, J.; Lester, D.; Harvey, P.

    1988-01-01

    An upper limit is presently determined for the mean intensity of the Jupiter northern Auroral UV/thermal hot spot's S1(1) H2 quadrupole emission, over an 8 sq arcsec illuminated beam; the value obtained is 4.2 X 10 to the -6th W/sq m per sr. It is suggested that the nonradiative deexitation of the H2 molecules via collisions with H may have been underestimated by Kim and Maguire (1986), due to uncertainties concerning auroral H density.

  7. Conformational studies by 1H and 13C NMR of lisinopril

    NASA Astrophysics Data System (ADS)

    Sakamoto, Yohko; Ishi, Tomoko

    1993-10-01

    Lisinopril, N-N-[( s-1-carboxy-3-phenylpropyl]- L-lysyl- L-proline) (MK-521), is an inhibitor of angiotensin-converting enzyme and a new drug for the treatment of hypertension. 1H and 13C NMR studies have shown that the s-cis equilibrium about the amide bond is strongly dependent on the configuration of the chiral centres. Vicinal coupling constants of stereochemical significance were obtained in deuterated solvent using NMR techniques. Comparison with values calculated for lisinopril using potential energy calculations and NMR show that lisinopril exists in preferred optimum conformation in solution.

  8. Design, synthesis and evaluation of 5-substituted 1-H-tetrazoles as potent anticonvulsant agents.

    PubMed

    Liao, Ai-Mei; Wang, Tiantian; Cai, Bangrong; Jin, Yi; Cheon, Seunghoon; Chun, ChangJu; Wang, Zengtao

    2017-04-01

    A series of 5-substituted 1-H-tetrazoles were designed and synthesized as potent anticonvulsant agents. Their preliminary anticonvulsant activities were evaluated using maximal electroshock and subcutaneous pentylenetetrazole (scPTZ) seizure tests. Neurotoxicity was determined using rotarod test. The results indicated that the compound 2j in scPTZ model exhibited the ED50 values of 83.3 mg/kg, superior to the standard drug ethosuximide with the maximum activity. In addition, compound 2k showed the most potent activity in MES model with ED50 value of 9.6 mg/kg and TD50 value of 189.5 mg/kg after intraperitoneal injection in mice, and displayed a high protective index (TD50/ED50) of 19.7 compared to reference antiepileptic drugs.

  9. Theoretical and experimental investigation of the 1H NMR spectrum of putrescine

    NASA Astrophysics Data System (ADS)

    Allouche, A. R.; Graveron-Demilly, D.; Fauvelle, F.; Aubert-Frécon, M.

    2008-12-01

    Chemical shifts δ and spin-spin coupling constants J have been calculated for the putrescine molecule, a polyamine present in prostate tissue, through a DFT/B3LYP/6-311++G(d,p)/PCM/(GIAO) approach, which has been shown to be accurate in previous work. From δ and J values, calculated for the first time for the isolated and the solvated putrescine, the 1H NMR spectra have been simulated. Comparisons between the calculated and the experimental NMR spectra at 400 MHz show a good agreement and allow to propose reliable values for the NMR spin Hamiltonian parameters of putrescine to be used as good starting values for further quantitation methods of metabolites in prostate tissue.

  10. Quantitative T1 mapping under precisely controlled graded hyperoxia at 7T.

    PubMed

    Bhogal, Alex A; Siero, Jeroen Cw; Zwanenburg, Jaco; Luijten, Peter R; Philippens, Marielle Ep; Hoogduin, Hans

    2017-04-01

    Increasing the concentration of oxygen dissolved in water is known to increase the recovery rate (R1 = 1/T1) of longitudinal magnetization (T1 relaxation). Direct T1 changes in response to precise hyperoxic gas challenges have not yet been quantified and the actual effect of increasing arterial oxygen concentration on the T1 of brain parenchyma remains unclear. The aim of this work was to use quantitative T1 mapping to measure tissue T1 changes in response to precisely targeted hyperoxic respiratory challenges ranging from baseline end-tidal oxygen (PetO2) to approximately 500 mmHg. We did not observe measureable T1 changes in either gray matter or white matter parenchymal tissue. The T1 of peripheral cerebrospinal fluid located within the sulci, however, was reduced as a function of PetO2. No significant T1 changes were observed in the ventricular cerebrospinal fluid under hyperoxia. Our results indicate that care should be taken to distinguish actual T1 changes from those which may be related to partial volume effects with cerebrospinal fluid, or regions with increased fluid content such as edema when examining hyperoxia-induced changes in T1 using methods based on T1-weighted imaging.

  11. Investigation of local symmetry in LiH3(SeO3)2 single crystals by 1H and 7Li nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Lim, Ae Ran

    2013-10-01

    The local environments of 1H and 7Li nuclei in LiH3(SeO3)2 crystals were investigated using FT NMR. The 7Li spectrum does changes from three resonance lines to one resonance line near Tm (=383 K). The variation in the splitting of the 7Li resonance lines with temperature indicates that the EFG at the Li sites produced by the (SeO3)2- groups varies with temperature. The changes in the temperature dependence of the intensity, line width, and spin-lattice relaxation time T1 near Tm for the 1H and 7Li nuclei coincide with the distortion of the structural framework surrounding each 1H and 7Li ion. Finally, the NMR results obtained here are compared to MH3(SeO3)2 (M = Na, K, and Cs) crystals previously reported.

  12. T1R2 and T1R3 subunits are individually unnecessary for normal affective licking responses to Polycose: implications for saccharide taste receptors in mice.

    PubMed

    Treesukosol, Yada; Blonde, Ginger D; Spector, Alan C

    2009-04-01

    The T1R2 and T1R3 proteins are expressed in taste receptor cells and form a heterodimer binding with compounds described as sweet by humans. We examined whether Polycose taste might be mediated through this heterodimer by testing T1R2 knockout (KO) and T1R3 KO mice and their wild-type (WT) littermate controls in a series of brief-access taste tests (25-min sessions with 5-s trials). Sucrose, Na-saccharin, and Polycose were each tested for three consecutive sessions with order of presentation varied among subgroups in a Latin-Square manner. Both KO groups displayed blunted licking responses and initiated significantly fewer trials of sucrose and Na-saccharin across a range of concentrations. KO mice tested after Polycose exposure demonstrated some degree of concentration-dependent licking of sucrose, likely attributable to learning related to prior postingestive experience. These results are consistent with prior findings in the literature, implicating the T1R2+3 heterodimer as the principal taste receptor for sweet-tasting ligands, and also provide support for the potential of postingestive experience to influence responding in the KO mice. In contrast, T1R2 KO and T1R3 KO mice displayed concentration-dependent licking responses to Polycose that tracked those of their WT controls and in some cases licked midrange concentrations more; the number of Polycose trials initiated overall did not differ between KO and WT mice. Thus, the T1R2 and T1R3 proteins are individually unnecessary for normal concentration-dependent licking of Polycose to be expressed in a brief-access test. Whether at least one of these T1R protein subunits is necessary for normal Polycose responsiveness remains untested. Alternatively, there may be a novel taste receptor(s) that mediates polysaccharide taste.

  13. T1R2 and T1R3 subunits are individually unnecessary for normal affective licking responses to polycose: implications for saccharide taste receptors in mice

    PubMed Central

    Treesukosol, Yada; Blonde, Ginger D.; Spector, Alan C.

    2009-01-01

    The T1R2 and T1R3 proteins are expressed in taste receptor cells and form a heterodimer binding with compounds described as sweet by humans. We examined whether Polycose taste might be mediated through this heterodimer by testing T1R2 knockout (KO) and T1R3 KO mice and their wild-type (WT) littermate controls in a series of brief-access taste tests (25-min sessions with 5-s trials). Sucrose, Na-saccharin, and Polycose were each tested for three consecutive sessions with order of presentation varied among subgroups in a Latin-Square manner. Both KO groups displayed blunted licking responses and initiated significantly fewer trials of sucrose and Na-saccharin across a range of concentrations. KO mice tested after Polycose exposure demonstrated some degree of concentration-dependent licking of sucrose, likely attributable to learning related to prior postingestive experience. These results are consistent with prior findings in the literature, implicating the T1R2+3 heterodimer as the principal taste receptor for sweet-tasting ligands, and also provide support for the potential of postingestive experience to influence responding in the KO mice. In contrast, T1R2 KO and T1R3 KO mice displayed concentration-dependent licking responses to Polycose that tracked those of their WT controls and in some cases licked midrange concentrations more; the number of Polycose trials initiated overall did not differ between KO and WT mice. Thus, the T1R2 and T1R3 proteins are individually unnecessary for normal concentration-dependent licking of Polycose to be expressed in a brief-access test. Whether at least one of these T1R protein subunits is necessary for normal Polycose responsiveness remains untested. Alternatively, there may be a novel taste receptor(s) that mediates polysaccharide taste. PMID:19158407

  14. Longitudinal T1 relaxation rate (R1) captures changes in short-term Mn exposure in welders.

    PubMed

    Lewis, Mechelle M; Flynn, Michael R; Lee, Eun-Young; Van Buren, Scott; Van Buren, Eric; Du, Guangwei; Fry, Rebecca C; Herring, Amy H; Kong, Lan; Mailman, Richard B; Huang, Xuemei

    2016-12-01

    We demonstrated recently that the T1 relaxation rate (R1) captured short-term Mn exposure in welders with chronic, relatively low exposure levels in a cross-sectional study. In the current study, we used a longitudinal design to examine whether R1 values reflect the short-term dynamics of Mn exposure. Twenty-nine welders were evaluated at baseline and 12 months. Occupational questionnaires estimated short-term welding exposure using welding hours in the 90days prior to each study visit (HrsW90). In addition, blood Mn levels, the pallidal index (PI; globus pallidus T1-weighted intensity (T1WI)/frontal white matter T1WI), and R1 values in brain regions of interest (ROIs) were determined as Mn biomarkers at each visit. Associations between changes in estimated welding exposure and changes in purported Mn biomarkers were assessed by Spearman's correlations with adjustment for age and baseline R1, HrsW90, and blood Mn values. Changes in welding hours (HrsW90: the short-term welding exposure estimate), was associated significantly with changes in R1 values in the putamen (r=0.541, p=0.005), caudate (R=0.453, p=0.023), globus pallidus (R=0.430, p=0.032), amygdala (R=0.461, p=0.020), and hippocampus (R=0.447, p=0.025), but not with changes in blood Mn levels or the PI. Changes in R1 values correlated with changes in the short-term welding exposure estimate, but not with more traditional measures of Mn exposure (blood Mn levels or PI). These results suggest that R1 may serve as a useful marker to capture the short-term dynamics in Mn brain accumulation related to welding exposure. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Liver Metabolite Concentrations Measured with 1H MR Spectroscopy

    PubMed Central

    Pettigrew, Roderic I.; Gharib, Ahmed M.

    2012-01-01

    Purpose: To determine the feasibility of measuring choline and glycogen concentrations in normal human liver in vivo with proton (hydrogen 1 [1H]) magnetic resonance (MR) spectroscopy. Materials and Methods: Signed consent to participate in an institutional review board–approved and HIPAA-compliant study was obtained from 46 subjects (mean age, 46 years ± 17 [standard deviation]; 24 women) consecutively recruited during 285 days. Navigator-gated MR images were used to select 8-mL volumes for point-resolved spectroscopy (PRESS) with a 35-msec echo time. Line widths were minimized with fast breath-hold B0 field mapping and further manual shimming. Navigator-gated spectra were recorded with and without water suppression to determine metabolite concentrations with water signals as an internal reference. In three subjects, echo time was varied to determine the glycogen and choline T2. Linear regression analysis was used to examine relations between choline, hepatic lipid content, body mass index, glycogen content, and age. Results: Choline concentrations could be determined in 46 of 48 studies and was found to be 8.6 mmol per kilogram of wet weight ± 3.1 (range, 3.8–17.6; n = 44). Twenty-seven spectra in 25 individuals with narrow line widths and low lipid content were adequate for quantitation of glycogen. The glycogen (glucosyl unit) concentration was 38.1 mmol/kg wet weight ± 14.4. The T2 of combined glycogen peaks in the liver of three subjects was 36 msec ± 8. Choline levels showed a weak but significant correlation with glycogen (r2 = 0.15; P < .05) but not with lipid content. Conclusion: Navigator-gated and gradient-echo shimmed PRESS 1H MR spectroscopy may allow quantification of liver metabolites that are important for understanding and identifying disorders of glucose and lipid metabolism. © RSNA, 2012 Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12112344/-/DC1 PMID:22891360

  16. Detection of prostate cancer with magnetic resonance imaging: optimization of T1-weighted, T2-weighted, dynamic-enhanced T1-weighted, diffusion-weighted imaging apparent diffusion coefficient mapping sequences and MR spectroscopy, correlated with biopsy and histopathological findings.

    PubMed

    Aydin, Hasan; Kizilgöz, Volkan; Tatar, Idil Güneş; Damar, Cağri; Ugan, Ali Riza; Paker, Irem; Hekimoğlu, Baki

    2012-01-01

    The aim of this study was to optimize and predict the most efficient magnetic resonance imaging (MRI) sequences; T1-weighted (T1W), T2-weighted (T2W), dynamic contrast-enhanced (DCE) T1W, diffusion-weighted imaging (DWI) apparent diffusion coefficient (ADC) mapping sequences and proton MR spectroscopy (H-MRS) for the detection of prostate cancer. After institutional review board approval and informed consent taken from all the patients, 40 patients with prostate cancer were included in this research. Two readers independently evaluated the results of T1W, T2W, DCE T1W, and DWI-ADC mapping sequences and proton H-MRS for the depiction of prostate cancer. Reference standard was the transrectal ultrasonography-guided biopsy and the surgical histopathological results. Statistical analysis was assessed by the Fisher exact t test, Wilcoxon signed rank test, variance analysis test with kappa (κ) values and receiver operating characteristics (ROC) curve for ADC values, choline (Cho)/citrate (Cit) and Cho+creatine (Cre)/Cit ratios for each observer. Based on both readers' results, sensitivity declined to 31% and specificity to 75% for the T1W sequence, sensitivity declined to 43% and specificity to 67% for the DCE T1W sequence, sensitivity declined to 46% and specificity to 68% for the T2W sequence, sensitivity declined to 29% and specificity to 82% for the DWI-ADC mapping; and specificity was 49% for the Cho/Cit and Cho+Cre/Cit ratios, sensitivity was 69% for the Cho/Cit ratio, and sensitivity was 70% for the Cho+Cre/Cit ratio for H-MRS. The T2W sequence and H-MRS presented significant statistical differences for the depiction of prostatic cancer (P < 0.05), the most efficient sequence to detect prostatic cancer was H-MRS: Cho+Cre/Cit and Cho/Cit ratios. Instead of using either sequences alone owing to low sensitivity and specificity rates, combined use of MRI techniques could easily improve the detection and staging of prostate cancer.

  17. T1 mapping of the myocardium: intra-individual assessment of post-contrast T1 time evolution and extracellular volume fraction at 3T for Gd-DTPA and Gd-BOPTA

    PubMed Central

    2012-01-01

    Purpose Myocardial T1 relaxation time (T1 time) and extracellular volume fraction (ECV) are altered in patients with diffuse myocardial fibrosis. The purpose of this study was to perform an intra-individual assessment of normal T1 time and ECV for two different contrast agents. Methods A modified Look-Locker Inversion Recovery (MOLLI) sequence was acquired at 3 T in 24 healthy subjects (8 men; 28 ± 6 years) at mid-ventricular short axis pre-contrast and every 5 min between 5-45 min after injection of a bolus of 0.15 mmol/kg gadopentetate dimeglumine (Gd-DTPA; Magnevist®) (exam 1) and 0.1 mmol/kg gadobenate dimeglumine (Gd-BOPTA; Multihance®) (exam 2) during two separate scanning sessions. T1 times were measured in myocardium and blood on generated T1 maps. ECVs were calculated as ΔR1myocardium/ΔR1blood*1−hematocrit. Results Mean pre-contrast T1 relaxation times for myocardium and blood were similar for both the first and second CMR exam (p > 0.5). Overall mean post-contrast myocardial T1 time was 15 ± 2 ms (2.5 ± 0.7%) shorter for Gd-DTPA at 0.15 mmol/kg compared to Gd-BOPTA at 0.1 mmol/kg (p < 0.01) while there was no significant difference for T1 time of blood pool (p > 0.05). Between 5 and 45 minutes after contrast injection, mean ECV values increased linearly with time for both contrast agents from 0.27 ± 0.03 to 0.30 ± 0.03 (p < 0.0001). Mean ECV values were slightly higher (by 0.01, p < 0.05) for Gd-DTPA compared to Gd-BOPTA. Inter-individual variation of ECV was higher (CV 8.7% [exam 1, Gd-DTPA] and 9.4% [exam 2, Gd-BOPTA], respectively) compared to variation of pre-contrast myocardial T1 relaxation time (CV 4.5% [exam 1] and 3.0% [exam 2], respectively). ECV with Gd-DTPA was highly correlated to ECV by Gd-BOPTA (r = 0.803; p < 0.0001). Conclusion In comparison to pre-contrast myocardial T1 relaxation time, variation in ECV values of normal subjects is larger. However, absolute differences in ECV

  18. Conformational behavior and tautomer selective photochemistry in low temperature matrices: the case of 5-(1H-tetrazol-1-yl)-1,2,4-triazole.

    PubMed

    Pagacz-Kostrzewa, M; Reva, I D; Bronisz, R; Giuliano, B M; Fausto, R; Wierzejewska, M

    2011-06-09

    The conformational properties and the photolysis behavior of one of the simplest N-C bonded bicyclic azoles, 5-(1H-tetrazol-1-yl)-1,2,4-triazole (T), were studied in argon and xenon matrices by infrared spectroscopy. Analysis of the experimental results was supported by extensive theoretical calculations carried out at the B3LYP/6-311++G(2d,2p) level of approximation. Out of the eight T minima located on the potential energy surface, the three most stable species were detected in low temperature matrices, namely, 5-(1H-tetrazol-1-yl)-1H-1,2,4-triazole (T1) and two conformers of 5-(1H-tetrazol-1-yl)-2H-1,2,4-triazole (T2a and T2b). With increase of the substrate temperature either during deposition of the matrices or during annealing the T2b → T2a conversion took place, in agreement with the predicted low energy barrier for this transformation (5.38 kJ mol(-1)). Both broad band and narrow band laser UV irradiations of T isolated in Xe and Ar matrices induce unimolecular decomposition involving cleavage of the tetrazole ring of T1 and T2a (T2b) that leads to the production of 1H-1,2,4-triazol-5-yl carbodiimide (P1) and 1H-1,2,4-triazol-3-yl carbodiimide (P2), respectively. When the laser is used, in addition to the main P1 and P2 photoproducts, several minor products could be successfully identified in the matrices: N-cyanocarbodiimide HNCNCN (detected for the first time) associated with nitrilimine HNNCH and HCN. An interesting phenomenon of tautomer-selective photochemistry was observed for the matrix-isolated compound. It could be explained by the different LUMO-HOMO energy gaps estimated for T1, T2a, and T2b, connected with different threshold energies necessary to start the photolysis of T1 and T2a (T2b).

  19. T1ρ MRI and Discography Pressure as Novel Biomarkers for Disc Degeneration and Low Back Pain

    PubMed Central

    Borthakur, Arijitt; Maurer, Philip M.; Fenty, Matthew; Wang, Chenyang; Berger, Rachelle; Yoder, Jonathon; Balderston, Richard A.; Elliott, Dawn M.

    2012-01-01

    Study Design Prospective MRI study of LBP patients requiring discography as part of their routine clinical diagnoses and asymptomatic age-matched volunteers. Objective To determine whether T1ρ MRI and discography opening pressure are quantitative biomarkers of disc degeneration in LBP patients and in asymptomatic volunteers. Summary of Background Data Disc degenerative disease (DDD), a common cause of low back pain (LBP), is related to the patient’s prognosis and serves as a target for therapeutic interventions. However, there are few quantitative measures in the clinical setting. Discography opening pressure (OP) and T1ρ MRI are potential biomarkers of DDD related to biochemical composition the intervertebral disc (IVD). Methods The Institutional Review Board approved all experiments and informed consent was provided by each subject. Patients being treated for LBP (n=17, 68 levels, mean age 44±6 years, range 30–53) and control (CTL) subjects (n=11, 44 levels, mean age 43±17, range 22–76) underwent T1ρ and T2 MRI on a Siemens 3T Tim Trio clinical scanner. The LBP patients also received multi-level provocative discography before their MRI. Opening Pressure (OP) was recorded as the pressure when fluid first enters the nucleus of the IVD. Results T1ρ was significantly lower in the painful discs (55.3ms±3.0 ms, mean ± std. error) from control (92.0±4.9 ms, p<0.001) and non-painful discs (83.6±3.2 ms, p<0.001). Mean OP for the painful discs (11.8±1.0 psi, mean ± std. error) was significantly lower than non-painful discs (19.1±0.7 psi, p<0.001). Both T1ρ and OP correlated moderately with Pfirrmann degenerative grade. ROC area under the curve was 0.91 for T1ρ MRI and 0.84 for OP for predicting painful discs. Conclusions T1ρ and OP are quantitative measures of degeneration that are consistent across both control subjects and LBP patients. A significant and strong correlation exists between T1ρ values and in vivo OP measurements obtained by

  20. FAIR exempting separate T (1) measurement (FAIREST): a novel technique for online quantitative perfusion imaging and multi-contrast fMRI.

    PubMed

    Lai, S; Wang, J; Jahng, G H

    2001-01-01

    A new pulse sequence, dubbed FAIR exempting separate T(1) measurement (FAIREST) in which a slice-selective saturation recovery acquisition is added in addition to the standard FAIR (flow-sensitive alternating inversion recovery) scheme, was developed for quantitative perfusion imaging and multi-contrast fMRI. The technique allows for clean separation between and thus simultaneous assessment of BOLD and perfusion effects, whereas quantitative cerebral blood flow (CBF) and tissue T(1) values are monitored online. Online CBF maps were obtained using the FAIREST technique and the measured CBF values were consistent with the off-line CBF maps obtained from using the FAIR technique in combination with a separate sequence for T(1) measurement. Finger tapping activation studies were carried out to demonstrate the applicability of the FAIREST technique in a typical fMRI setting for multi-contrast fMRI. The relative CBF and BOLD changes induced by finger-tapping were 75.1 +/- 18.3 and 1.8 +/- 0.4%, respectively, and the relative oxygen consumption rate change was 2.5 +/- 7.7%. The results from correlation of the T(1) maps with the activation images on a pixel-by-pixel basis show that the mean T(1) value of the CBF activation pixels is close to the T(1) of gray matter while the mean T(1) value of the BOLD activation pixels is close to the T(1) range of blood and cerebrospinal fluid. Copyright 2001 John Wiley & Sons, Ltd.

  1. 3-hydroxy-2(1H)-pyridinone chelating agents

    DOEpatents

    Raymond, Kenneth N.; Xu, Jide

    1997-01-01

    Disclosed is a series of improved metal chelating agents, which are highly effective upon both injection and oral administration; several of the most effective are of low toxicity. These chelating agents incorporate within their structure 1-hydroxy-2-pyridinone (1,2-HOPO) and 3-hydroxy-2-pyridinone (3,2-HOPO) moieties with a substituted carbamoyl group ortho to the hydroxy or oxo groups of the hydroxypyridinone ring. The electron-withdrawing carbamoyl group increases the acidity of the hydroxypyridinones. In the metal complexes of said chelating agents, the amide protons form very strong hydrogen bonds with its adjacent HOPO oxygen donor, making these complexes very stable at physiological conditions. The terminal N-substituents provides a certain degree of lipophilicity to said 3,2-HOPO, increasing oral activity. Also disclosed is a method of making the chelating agents and a method of producing a known compound, 3-hydroxy-1-alkyl-2(1H)pyridinone, used as a precursor to the chelating agent, safely and in large quantities.

  2. 1H NMR Metabolomics Analysis of Glioblastoma Subtypes

    PubMed Central

    Cuperlovic-Culf, Miroslava; Ferguson, Dean; Culf, Adrian; Morin, Pier; Touaibia, Mohamed

    2012-01-01

    Glioblastoma multiforme (GBM) is the most common form of malignant glioma, characterized by unpredictable clinical behaviors that suggest distinct molecular subtypes. With the tumor metabolic phenotype being one of the hallmarks of cancer, we have set upon to investigate whether GBMs show differences in their metabolic profiles. 1H NMR analysis was performed on metabolite extracts from a selection of nine glioblastoma cell lines. Analysis was performed directly on spectral data and on relative concentrations of metabolites obtained from spectra using a multivariate regression method developed in this work. Both qualitative and quantitative sample clustering have shown that cell lines can be divided into four groups for which the most significantly different metabolites have been determined. Analysis shows that some of the major cancer metabolic markers (such as choline, lactate, and glutamine) have significantly dissimilar concentrations in different GBM groups. The obtained lists of metabolic markers for subgroups were correlated with gene expression data for the same cell lines. Metabolic analysis generally agrees with gene expression measurements, and in several cases, we have shown in detail how the metabolic results can be correlated with the analysis of gene expression. Combined gene expression and metabolomics analysis have shown differential expression of transporters of metabolic markers in these cells as well as some of the major metabolic pathways leading to accumulation of metabolites. Obtained lists of marker metabolites can be leveraged for subtype determination in glioblastomas. PMID:22528487

  3. 3-hydroxy-2(1H)-pyridinone chelating agents

    DOEpatents

    Raymond, K.N.; Xu, J.

    1997-04-29

    Disclosed is a series of improved metal chelating agents, which are highly effective upon both injection and oral administration; several of the most effective are of low toxicity. These chelating agents incorporate within their structure 1-hydroxy-2-pyridinone (1,2-HOPO) and 3-hydroxy-2-pyridinone (3,2-HOPO) moieties with a substituted carbamoyl group ortho to the hydroxy or oxo groups of the hydroxypyridinone ring. The electron-withdrawing carbamoyl group increases the acidity of the hydroxypyridinones. In the metal complexes of the chelating agents, the amide protons form very strong hydrogen bonds with its adjacent HOPO oxygen donor, making these complexes very stable at physiological conditions. The terminal N-substituents provides a certain degree of lipophilicity to the 3,2-HOPO, increasing oral activity. Also disclosed is a method of making the chelating agents and a method of producing a known compound, 3-hydroxy-1-alkyl-2(1H)pyridinone, used as a precursor to the chelating agent, safely and in large quantities. 2 figs.

  4. Mapping of prostate cancer by 1H MRSI.

    PubMed

    Kobus, Thiele; Wright, Alan J; Scheenen, Tom W J; Heerschap, Arend

    2014-01-01

    In many studies, it has been demonstrated that (1)H MRSI of the human prostate has great potential to aid prostate cancer management, e.g. in the detection and localisation of cancer foci in the prostate or in the assessment of its aggressiveness. It is particularly powerful in combination with T2 -weighted MRI. Nevertheless, the technique is currently mainly used in a research setting. This review provides an overview of the state-of-the-art of three-dimensional MRSI, including the specific hardware required, dedicated data acquisition sequences and information on the spectral content with background on the MR-visible metabolites. In clinical practice, it is important that relevant MRSI results become available rapidly, reliably and in an easy digestible way. However, this functionality is currently not fully available for prostate MRSI, which is a major obstacle for routine use by inexperienced clinicians. Routine use requires more automation in the processing of raw data than is currently available. Therefore, we pay specific attention in this review on the status and prospects of the automated handling of prostate MRSI data, including quality control. The clinical potential of three-dimensional MRSI of the prostate is illustrated with literature examples on prostate cancer detection, its localisation in the prostate, its role in the assessment of cancer aggressiveness and in the selection and monitoring of therapy.

  5. Preliminary 1H NMR study on archaeological waterlogged wood.

    PubMed

    Maccotta, Antonella; Fantazzini, Paola; Garavaglia, Carla; Donato, Ines D; Perzia, Patrizia; Brai, Maria; Morreale, Filippa

    2005-01-01

    Magnetic Resonance Relaxation (MRR) and Magnetic Resonance Imaging (MRI) are powerful tools to obtain detailed information on the pore space structure that one is unlikely to obtain in other ways. These techniques are particularly suitable for Cultural Heritage materials, because they use water 1H nuclei as a probe. Interaction with water is one of the main causes of deterioration of materials. Porous structure in wood, for example, favours the penetration of water, which can carry polluting substances and promote mould growth. A particular case is waterlogged wood from underwater discoveries and moist sites; in fact, these finds are very fragile because of chemical, physical and biological decay from the long contact with the water. When wood artefacts are brought to the surface and directly dried in air, there is the collapse of the cellular structures, and wood loses its original form and dimensions and cannot be used for study and museum exhibits. In this work we have undertaken the study of some wood finds coming from Ercolano's harbour by MRR and MRI under different conditions, and we have obtained a characterization of pore space in wood and images of the spatial distribution of the confined water in the wood.

  6. Thinking bedside at the bench: the NOD mouse model of T1DM

    PubMed Central

    Reed, James C.; Herold, Kevan C.

    2015-01-01

    Studies over the past 35 years in the nonobese diabetic (NOD) mouse have shown that a number of agents can prevent or even reverse type 1 diabetes mellitus (T1DM); however, these successes have not been replicated in human clinical trials. Although some of these interventions have delayed disease onset or progression in subsets of participants, none have resulted in a complete cure. Even in the most robust responders, the treatments do not permanently preserve insulin secretion or stimulate the proliferation of β cells, as has been observed in mice. The shortfalls of translating NOD mouse studies into the clinic questions the value of using this model in preclinical studies. In this Perspectives, we suggest how immunological and genetic differences between NOD mice and humans might contribute to the differential outcomes and suggest ways in which the mouse model might be modified or applied as a tool to develop treatments and improve understanding of clinical trial outcomes. PMID:25623120

  7. Uncertainty in the analysis of tracer kinetics using dynamic contrast-enhanced T1-weighted MRI.

    PubMed

    Buckley, David L

    2002-03-01

    In recent years a number of physiological models have gained prominence in the analysis of dynamic contrast-enhanced T1-weighted MRI data. However, there remains little evidence to support their use in estimating the absolute values of tissue physiological parameters such as perfusion, capillary permeability, and blood volume. In an attempt to address this issue, data were simulated using a distributed pathway model of tracer kinetics, and three published models were fitted to the resultant concentration-time curves. Parameter estimates obtained from these fits were compared with the parameters used for the simulations. The results indicate that the use of commonly accepted models leads to systematic overestimation of the transfer constant, Ktrans, and potentially large underestimates of the blood plasma volume fraction, Vp. In summary, proposals for a practical approach to physiological modeling using MRI data are outlined.

  8. Untargeted 1H-NMR metabolomics in CSF: toward a diagnostic biomarker for motor neuron disease.

    PubMed

    Blasco, Hélène; Nadal-Desbarats, Lydie; Pradat, Pierre-François; Gordon, Paul H; Antar, Catherine; Veyrat-Durebex, Charlotte; Moreau, Caroline; Devos, David; Mavel, Sylvie; Emond, Patrick; Andres, Christian R; Corcia, Philippe

    2014-04-01

    To develop a CSF metabolomics signature for motor neuron disease (MND) using (1)H-NMR spectroscopy and to evaluate the predictive value of the profile in a separate cohort. We collected CSF from patients with MND and controls and analyzed the samples using (1)H-NMR spectroscopy. We divided the total patient sample in a 4:1 ratio into a training cohort and a test cohort. First, a metabolomics signature was created by statistical modeling in the training cohort, and then the analyses tested the predictive value of the signature in the test cohort. We conducted 10 independent trials for each step. Finally, we identified the compounds that contributed most consistently to the metabolome profile. Analysis of CSF from 95 patients and 86 controls identified a diagnostic profile for MND (R(2)X > 22%, R(2)Y > 93%, Q(2) > 66%). The best model selected the correct diagnosis with mean probability of 99.31% in the training cohort. The profile discriminated between diagnostic groups with 78.9% sensitivity and 76.5% specificity in the test cohort. Metabolites linked to pathophysiologic pathways in MND (i.e., threonine, histidine, and molecules related to the metabolism of branched amino acids) were among the discriminant compounds. CSF metabolomics using (1)H-NMR spectroscopy can detect a reproducible metabolic signature for MND with reasonable performance. To our knowledge, this is the first metabolomics study that shows that a validation in separate cohorts is feasible. These data should be considered in future biomarker studies. This study provides Class III evidence that CSF metabolomics accurately distinguishes MNDs from other neurologic diseases.

  9. Rate and Regulation of Copper Transport by Human Copper Transporter 1 (hCTR1)*

    PubMed Central

    Maryon, Edward B.; Molloy, Shannon A.; Ivy, Kristin; Yu, Huijun; Kaplan, Jack H.

    2013-01-01

    Human copper transporter 1 (hCTR1) is a homotrimer of a 190-amino acid monomer having three transmembrane domains believed to form a pore for copper permeation through the plasma membrane. The hCTR1-mediated copper transport mechanism is not well understood, nor has any measurement been made of the rate at which copper ions are transported by hCTR1. In this study, we estimated the rate of copper transport by the hCTR1 trimer in cultured cells using 64Cu uptake assays and quantification of plasma membrane hCTR1. For endogenous hCTR1, we estimated a turnover number of about 10 ions/trimer/s. When overexpressed in HEK293 cells, a second transmembrane domain mutant of hCTR1 (H139R) had a 3-fold higher Km value and a 4-fold higher turnover number than WT. Truncations of the intracellular C-terminal tail and an AAA substitution of the putative metal-binding HCH C-terminal tripeptide (thought to be required for transport) also exhibited elevated transport rates and Km values when compared with WT hCTR1. Unlike WT hCTR1, H139R and the C-terminal mutants did not undergo regulatory endocytosis in elevated copper. hCTR1 mutants combining methionine substitutions that block transport (M150L,M154L) on the extracellular side of the pore and the high transport H139R or AAA intracellular side mutations exhibited the blocked transport of M150L,M154L, confirming that Cu+ first interacts with the methionines during permeation. Our results show that hCTR1 elements on the intracellular side of the hCTR1 pore, including the carboxyl tail, are not essential for permeation, but serve to regulate the rate of copper entry. PMID:23658018

  10. 1H NMR relaxometry, viscometry, and PFG NMR studies of magnetic and nonmagnetic ionic liquids.

    PubMed

    Daniel, Carla I; Chávez, Fabián Vaca; Feio, Gabriel; Portugal, Carla A M; Crespo, João G; Sebastião, Pedro J

    2013-10-03

    A study is presented of the molecular dynamics and of the viscosity in pure [Aliquat][Cl] ionic liquid and in a mixture of [Aliquat][Cl] with 1% (v/v) of [Aliquat][FeCl4]. The (1)H spin-lattice relaxation rate, R1, was measured by NMR relaxometry between 8 and 300 MHz. In addition, the translation self-diffusion, D, was measured by pulse field gradient NMR. The ILs' viscosity was measured as a function of an applied magnetic field, B, and it was found that the IL mixture's viscosity decreased with increasing B, whereas the [Aliquat][Cl] viscosity is independent of B. All experimental results were analyzed taking into account the viscosity's magnetic field dependence, assuming a modified Stokes-Einstein diffusion/viscosity relation. The main difference between the relaxation mechanisms responsible for R1 in the two IL systems is related to the additional paramagnetic relaxation contribution associated with the (1)H spins-[FeCl4] paramagnetic moments' interactions. Cross-relaxation cusps in the R1 dispersion, associated with (35)Cl and (1)H nuclear spins in the IL systems, were detected. The R1 model considered was successfully fitted to the experimental results, and it was possible to estimate the value of D at zero field in the case of the IL mixture which was consistent with the values of D measured at 7 and 14.1 T and with the magnetic field dependence estimated from the viscosity measurements. It was observed that a small concentration of [Aliquat][FeCl4] in the [Aliquat][Cl] was enough to produce a "superparamagnetic"-like effect and to change the IL mixture's molecular dynamics and viscosity and to allow for their control with an external magnetic field.

  11. Ultra-low field T1 vs. T1rho at 3T and 7T: study of rotationally immobilized protein gels and animal brain tissues

    NASA Astrophysics Data System (ADS)

    Dong, Hui; Inglis, Ben; Barr, Ian; Clarke, John

    2015-03-01

    Clinical magnetic resonance imaging (MRI) machines operating in static fields of typically 1.5 T or 3 T can capture information on slow molecular dynamics utilizing the so-called T1rho technique. This technique, in which a radiofrequency (RF) spin-lock field is applied with microtesla amplitude, has been used, for example, to determine the onset time of stroke in studies on rats. The long RF pulse, however, may exceed the specific absorption rate (SAR) limit, putting subjects at risk. Ultra-low-field (ULF) MRI, based on Superconducting Quantum Interference Devices (SQUIDs), directly detects proton signals at a static magnetic field of typically 50-250 μT. Using our ULF MRI system with adjustable static field of typically 55 to 240 μT, we systematically measured the T1 and T2 dispersion profiles of rotationally immobilized protein gels (bovine serum albumin), ex vivo pig brains, and ex vivo rat brains with induced stroke. Comparing the ULF results with T1rho dispersion obtained at 3 T and 7 T, we find that the degree of protein immobilization determines the frequency-dependence of both T1 and T1rho. Furthermore, T1rho and ULF T1 show similar results for stroke, suggesting that ULF MRI may be used to image traumatic brain injury with negligible SAR. This research was supported by the Henry H. Wheeler, Jr. Brain Imaging Center and the Donaldson Trust.

  12. Quantifying Temperature-Dependent T1 Changes in Cortical Bone Using Ultrashort Echo-Time MRI

    PubMed Central

    Han, Misung; Rieke, Viola; Scott, Serena J; Ozhinsky, Eugene; Salgaonkar, Vasant A; Jones, Peter D; Larson, Peder E Z; Diederich, Chris J; Krug, Roland

    2015-01-01

    Purpose To demonstrate the feasibility of using ultrashort echo-time (UTE) MRI to quantify T1 changes in cortical bone due to heating. Methods Variable flip-angle T1 mapping combined with 3D UTE imaging was used to measure T1 in cortical bone. A calibration experiment was performed to detect T1 changes with temperature in ex vivo cortical bone samples from a bovine femur. Ultrasound heating experiments were performed using an interstitial applicator in ex vivo bovine femur specimens, and heat-induced T1 changes were quantified. Results The calibration experiment demonstrated that T1 increases with temperature in cortical bone. We observed a linear relationship between temperature and T1 with a linear coefficient of 0.67–0.84 ms/°C over a range of 25–70°C. The ultrasound heating experiments showed increased T1 changes in the heated regions, and the relationship between the temperature changes and T1 changes was similar to that of the calibration. Conclusion We demonstrated a temperature dependence of T1 in ex vivo cortical bone using a variable flip-angle UTE T1 mapping method. PMID:26390357

  13. T1ρ MRI Quantification of Arthroscopically-Confirmed Cartilage Degeneration

    PubMed Central

    Witschey, Walter RT; Borthakur, Arijitt; Fenty, Matt; Kneeland, J Bruce; Lonner, Jess H; McArdle, Erin L.; Sochor, Matt; Reddy, Ravinder

    2010-01-01

    9 asymptomatic subjects and 6 patients underwent T1ρ MRI to determine whether Outerbridge grade 1 or 2 cartilage degeneration observed during arthroscopy could be detected noninvasively. MRI was performed 2–3 months post-arthroscopy using sagittal T1-weighted and axial and coronal T1ρ MRI from which spatial T1ρ relaxation maps were calculated from segmented T1-weighted images. Median T1ρ relaxation times of patients with arthroscopically documented cartilage degeneration and asymptomatic subjects were significantly different (p < 0.001) and median T1ρ exceeded asymptomatic articular cartilage median T1ρ by 2.5 to 9.2 ms. In 8 observations of mild cartilage degeneration at arthroscopy (Outerbridge grades 1 and 2), mean compartment T1ρ was elevated in 5, but in all observations, large foci of increased T1ρ were observed. It was determined that T1ρ could detect some, but not all, Outerbridge grade 1 and 2 cartilage degeneration but that a larger patient population is needed to determine the sensitivity to these changes. PMID:20432308

  14. T1ρ magnetic resonance: basic physics principles and applications in knee and intervertebral disc imaging

    PubMed Central

    Zhang, Qinwei; Li, Xiaojuan; Chen, Weitian; Ahuja, Anil; Yuan, Jing

    2015-01-01

    T1ρ relaxation time provides a new contrast mechanism that differs from T1- and T2-weighted contrast, and is useful to study low-frequency motional processes and chemical exchange in biological tissues. T1ρ imaging can be performed in the forms of T1ρ-weighted image, T1ρ mapping and T1ρ dispersion. T1ρ imaging, particularly at low spin-lock frequency, is sensitive to B0 and B1 inhomogeneity. Various composite spin-lock pulses have been proposed to alleviate the influence of field inhomogeneity so as to reduce the banding-like spin-lock artifacts. T1ρ imaging could be specific absorption rate (SAR) intensive and time consuming. Efforts to address these issues and speed-up data acquisition are being explored to facilitate wider clinical applications. This paper reviews the T1ρ imaging’s basic physic principles, as well as its application for cartilage imaging and intervertebral disc imaging. Compared to more established T2 relaxation time, it has been shown that T1ρ provides more sensitive detection of proteoglycan (PG) loss at early stages of cartilage degeneration. T1ρ has also been shown to provide more sensitive evaluation of annulus fibrosis (AF) degeneration of the discs. PMID:26807369

  15. T1ρ magnetic resonance: basic physics principles and applications in knee and intervertebral disc imaging.

    PubMed

    Wáng, Yì-Xiáng J; Zhang, Qinwei; Li, Xiaojuan; Chen, Weitian; Ahuja, Anil; Yuan, Jing

    2015-12-01

    T1ρ relaxation time provides a new contrast mechanism that differs from T1- and T2-weighted contrast, and is useful to study low-frequency motional processes and chemical exchange in biological tissues. T1ρ imaging can be performed in the forms of T1ρ-weighted image, T1ρ mapping and T1ρ dispersion. T1ρ imaging, particularly at low spin-lock frequency, is sensitive to B0 and B1 inhomogeneity. Various composite spin-lock pulses have been proposed to alleviate the influence of field inhomogeneity so as to reduce the banding-like spin-lock artifacts. T1ρ imaging could be specific absorption rate (SAR) intensive and time consuming. Efforts to address these issues and speed-up data acquisition are being explored to facilitate wider clinical applications. This paper reviews the T1ρ imaging's basic physic principles, as well as its application for cartilage imaging and intervertebral disc imaging. Compared to more established T2 relaxation time, it has been shown that T1ρ provides more sensitive detection of proteoglycan (PG) loss at early stages of cartilage degeneration. T1ρ has also been shown to provide more sensitive evaluation of annulus fibrosis (AF) degeneration of the discs.

  16. Optical probes of excitonic phases in quantum Hall bilayers at νT=1*

    NASA Astrophysics Data System (ADS)

    Pellegrini, Vittorio

    2009-03-01

    In this talk we discuss our recent inelastic light scattering results that shed light on the interplay between incompressible and compressible quantum phases of electron bilayers at total filling factor νT = 1. In the regime of finite values of tunneling gaps, we observe a quantum phase transformation between composite fermion (CF) metal and incompressible excitonic states as the tunneling gap is reduced. We show that the transition becomes discontinuous (first-order) by impacts of different terms of the electron-electron interactions that prevail on weak residual disorder [1]. The evidence is based on precise determinations of the excitonic order parameter and of measurements of CF spin excitations by resonant inelastic light scattering close to the phase boundary [2,3]. While there is marked softening of low-lying excitations, our experiments underpin the roles of competing order parameters linked to quasi-particle correlations in removing the divergence of quantum fluctuations [4]. In the regime of vanishingly small tunneling gaps we show that the abrupt disappearing of CF spin excitations below the spin-wave indicates the emergence of the inter-layer correlated quantum Hall state in the vicinity of