Glutamate N-methyl-d-aspartate (NMDA) receptor antagonists exert fast-acting antidepressant effects, providing a promising way to develop a new classification of antidepressant that targets the glutamatergic system. In the present study, we examined the potential antidepressant action of 7-chlorokynurenic acid (7-CTKA), a glycine recognition site NMDA receptor antagonist, in a series of behavioural models of depression and determined the molecular mechanisms that underlie the behavioural actions of 7-CTKA.
We administered the forced swim test, novelty-suppressed feeding test, learned helplessness paradigm and chronic mild stress (CMS) paradigm in male rats to evaluate the possible rapid antidepressant-like actions of 7-CTKA. In addition, we assessed phospho-glycogen synthase kinase-3β (p-GSK3β) level, mammalian target of rapamycin (mTOR) function, and postsynaptic protein expression in the medial prefrontal cortex (mPFC) and hippocampus.
Acute 7-CTKA administration produced rapid antidepressant-like actions in several behavioural tests. It increased p-GSK3β, enhanced mTOR function and increased postsynaptic protein levels in the mPFC. Activation of GSK3β by LY294002 completely blocked the antidepressant-like effects of 7-CTKA. Moreover, 7-CTKA did not produce rewarding properties or abuse potential.
It is possible that 7-CTKA modulates glutamatergic transmission, thereby causing enduring alterations of GSK3β and mTOR signalling, although we did not provide direct evidence to support this possibility. Thus, the therapeutic involvement of synaptic adaptions engaged by 7-CTKA requires further study.
Our findings demonstrate that acute 7-CTKA administration produced rapid antidepressant-like effects, indicating that the behavioural response to 7-CTKA is mediated by GSK3β and mTOR signalling function in the mPFC.
Neuropathic pain is common and difficult to treat. Recently a technique was developed to selectively inhibit nociceptive inputs by simultaneously applying two drugs: capsaicin, a transient receptor potential vanilloid receptor 1 channel activator and QX-314, a lidocaine derivative that intracellularly blocks sodium channels. We used this technique to investigate whether transient receptor potential vanilloid receptor 1-expressing nociceptors contribute to neuropathic pain.
The rat chronic constriction injury model was used to induce neuropathic pain in order to test the analgesic effects of both peripheral (perisciatic) and central (intrathecal) administration of the QX-314/capsaicin combination. The Hargreaves and von Frey tests were used to monitor evoked pain-like behaviors and visual observations were used to rank spontaneous pain-like behaviors.
Perisciatic injections of the QX-314/capsaicin combination transiently increased the withdrawal thresholds by ~3 fold for mechanical and thermal stimuli in rats (n = 6/group) with nerve injuries suggesting that peripheral transient receptor potential vanilloid receptor 1-expressing nociceptors contribute to neuropathic pain. In contrast, intrathecal administration of the QX-314/capsaicin combination did not alleviate pain-like behaviors (n = 5/group). Surprisingly, intrathecal QX-314 alone (n = 9) or in combination with capsaicin (n = 8) evoked spontaneous pain-like behaviors.
Data from the perisciatic injections suggested that a component of neuropathic pain was mediated by peripheral nociceptive inputs. The role of central nociceptive terminals could not be determined because of the severe side effects of the intrathecal drug combination. We concluded that only peripheral blockade of transient receptor potential vanilloid receptor 1-expressing nociceptive afferents by the QX-314/capsaicin combination was effective at reducing neuropathic allodynia and hyperalgesia.
Peritumoral liver tissue could play a potential role in hepatocellular carcinoma (HCC) progression and patient survival via angiogenesis- and lymphangiogensis-related factors. The prognostic role of these factors in hepatocytes and stromal cells in HCC patients after curative resection remains to be explored.
Tumor tissue and surrounding peritumoral tissue were obtained from 145 resected HCC patients without lymph node metastasis (LNM) and 37 resected HCC patients with LNM. Tissue microarrays were constructed from duplicate cores of tumor tissue and surrounding peritumoral tissue from each resected specimen. Immunohistochemistry and real-time polymerase chain reaction were used to evaluate the expression of vascular endothelial growth factor-A (VEGF-A), VEGF-C, VEGF receptor-1(VEGFR-1), VEGFR-2, and VEGFR-3. Macrophage infiltration was determined by CD68 staining. Correlations between the expression of these factors and overall survival (OS) and time to recurrence (TTR) were studied.
The peritumoral expression of VEGF-A, VEGF-C, VEGFR-1, VEGFR-2, and VEGFR-3 were significantly higher than expression of these factors in tumors. VEGFR-1 was mostly located in peritumoral macrophages, while VEGF-C and VEGFR-3 were mostly located in peritumoral hepatocytes. HCC with high peritumoral co-expression of VEGF-C, VEGFR-1, and VEGFR-3 was associated with higher peritumoral distribution of macrophages (0.87%±0.26% versus 0.45%±0.20%), LNM (32.4% versus 12.0%), shorter TTR (10.2 months versus 34.5 months), and poor prognosis (19.4 months versus 49.3 months).
Expression of VEGF-C, VEGFR-1, and VEGFR-3 in peritumoral liver tissue is associated with a unique type of HCC that has a poorer outcome after hepatectomy.
This study demonstrates the feasibility of simultaneously detecting human brain metabolites labeled by two substrates infused in a sequential order. In vivo 13C spectra of carboxylic/amide carbons were acquired only during the infusion of the second substrate. This approach allowed dynamic detection of 13C labeling from two substrates with considerably different labeling patterns. [2-13C]glucose and [U-13C6]glucose were used to generate singlet and doublet signals of the same carboxylic/amide carbon atom, respectively. Because of the large one-bond 13C-13C homonuclear J coupling between a carboxylic/amide carbon and an aliphatic carbon (~50 Hz), the singlet and doublet signals of the same carboxylic/amide carbon were well distinguished. The results demonstrated that different 13C isotopomer patterns could be simultaneously and distinctly measured in vivo in a clinical setting at 3 Tesla.
In vivo 13C MRS; Carboxylic/amide spectral region; Sequential infusion
Lung cancer is the leading cause of cancer death worldwide, due to its late diagnosis and poor outcome. MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression at the posttranscriptional levels by either degrading or blocking translation of messenger RNA targets. Accumulating evidence indicates that miRNAs play a pivotal role in the development and progression of human malignancies, including lung cancer.
In this review, the authors focus on 1) application of miRNA-based biomarkers to help classify lung cancer, 2) application of the miRNA biomarkers for the early detection of lung cancer, and 3) use of miRNAs as biomarkers to predict outcomes of lung cancer.
MiRNAs provide promising biomarkers for the diagnosis and prognosis of lung cancer. The developed miRNA biomarkers should be comprehensively and prospectively validated in clinical trials before being used in laboratory settings.
MiRNAs; biomarker; diagnosis; prognosis; lung cancer
The purpose of this study was to evaluate the inhibitory effect of targeted folate-functionalized micelles containing superparamagnetic iron oxide nanoparticles (SPIONs) and sorafenib on human hepatic carcinoma (HepG2) cells in vitro, and to observe the feasibility of surveillance of this targeting therapeutic effect by magnetic resonance imaging.
Sorafenib and SPIONs were loaded into polymeric micelles. The targeted nanocarrier was synthesized by functionalizing the micelles with folate. Folate-free micelles loaded with sorafenib and SPIONs were used as control (nontargeted) micelles. Uptake of the nanocarrier by cells was assessed using Prussian blue staining after 1 hour of incubation with the polymeric micelles. The inhibitory effect of the targeted micelles on HepG2 cell proliferation at various concentrations of sorafenib was assessed in vitro using the methyl thiazolyl tetrazolium (MTT) assay and apoptotic analysis using flow cytometry. Magnetic resonance imaging using a clinical 1.5 T scanner was performed to detect changes in the signal intensity of cells after incubation with the targeted micelles.
Prussian blue staining showed significantly more intracellular SPIONs in cells incubated with the targeted micelles than those incubated with nontargeted micelles. The MTT assay showed that the average inhibitory ratio in the targeted group was significantly higher than that in the nontargeted group (38.13% versus 22.54%, P = 0.028). The mean apoptotic rate in the targeted cells, nontargeted cells, and untreated cells was 17.01%, 11.04%, and 7.89%, respectively. The apoptotic rate in the targeted cells was significantly higher than that in the nontargeted cells (P = 0.043). The T2 signal intensity on magnetic resonance imaging of cells treated with the targeted micelles decreased significantly with increasing concentrations of sorafenib in the cell culture medium, but there was no obvious decrease in signal intensity in cells treated with the nontargeted micelles.
Folate-functionalized polymeric micelles loaded with SPIONs and sorafenib inhibited proliferation and induced apoptosis of HepG2 cells in vitro. The inhibitory events caused by targeted micelles can be monitored using clinical magnetic resonance.
folic acid; sorafenib; magnetic resonance imaging; superparamagnetic iron oxide nanoparticles
Interferon (IFN)-α is effective in inhibiting tumor growth and metastasis of hepatocellular carcinoma (HCC). However, the biologic mechanisms of IFN-α treatment in lung metastasis are not yet clear.
The effect of IFN-α treatment was studied by using an orthotopic xenograft model and measuring tumor size and lung metastasis. Pretreatment with IFN-α before implantation of tumor was done to explore the effect of IFN-α on lung tissues. Cytokines and macrophages were measured by immunohistochemistry and/or PCR assay, using human origin or mouse origin primers to differentiate the sources. Circulating tumor cells (CTCs) were also assayed by flow cytometry.
IFN-α treatment did not decrease the number of CTCs (0.075%±0.020% versus 0.063%±0.018%, P = 0.574, IFN-α–treated versus control groups), but did decrease the number and size of lung metastasis (number: 1.75±1.0 versus 28.0±6.3, P = 0.008; size [pixels]: 116.8±72.2 versus 5226.4±1355.7, P = 0.020), and inhibited macrophage infiltration (0.20%±0.04% versus 1.36%±0.21%, P = 0.0058) and alteration of matrix metalloproteinase (MMP)-9 expression (mean integrated optical density (IOD): 5.1±1.7 versus 21.9±0.4, P<0.000) in the lung, which was independent of the primary tumor.
IFN-α inhibited lung metastasis by directly modulating the lung microenvironment.
Acamprosate is approved for treatment of alcoholism, but its mechanism of action remains unclear. Animal studies suggest that a persistent hyperglutamatergic state contributes to the pathophysiology of alcoholism, and that acamprosate may exert its actions by intervening in this process. Human translation of these findings is lacking.
To examine whether acamprosate modulates indices of central glutamate levels in recently abstinent alcohol dependent patients, as measured by proton nuclear magnetic resonance spectroscopy (1H-MRS).
A 4 week, double-blind, placebo-controlled randomized controlled experimental medicine study, with 1H-MRS measures obtained on day 4 and 25.
NIAAA inpatient research unit at the NIH Clinical Center.
Thirty three patients who met the DSM-IV criteria for alcohol dependence and were admitted for medically supervised withdrawal from ongoing alcohol use.
Four weeks of acamprosate (initial oral loading followed by 1998mg daily) or matched placebo, initiated at the time of admission.
The main outcome was the glutamate/creatine ratio (Glu) as determined by single voxel 1H-MRS within the anterior cingulate. Exploratory neuroendocrine, biochemical and behavioral outcomes were also collected, as well as safety/tolerability – related measures.
There was a highly significant suppression of Glu over time by acamprosate (time × treatment interaction: F[1, 29]=13.5, p<0.001). Cerebrospinal fluid (CSF) levels of glutamate obtained in a subset of patients 4 weeks into abstinence were uncorrelated with the MRS measures and were unaffected by treatment, but were strongly correlated (R2=0.48, p<0.001) with alcohol dependence severity. Other exploratory outcomes, including repeated Dex/CRH tests, as well as psychiatric ratings were unaffected. Among tolerability measures, gastrointestinal symptoms were significantly greater in acamprosate treated subjects, in agreement with the established profile of acamprosate.
MRS measures of central glutamate are reduced over time when acamprosate is initiated at the onset of alcohol abstinence.
www.clinicaltrials.gov Identifier: NCT00106106
acamprosate; alcohol; magnetic resonance spectroscopy; glutamate
In recent years, interests combining the exploration of tumor necrosis factor receptor-associated factor 4 (TRAF4) and TRAF6 in immune cells and transgenic mice are emerging. Although it has been found that TRAF4 and TRAF6 share the same TRAF binding sites, comprehensive study of TRAF4 and TRAF6 in inflammatory bowel disease (IBD) is still lacking. This paper shows similar and different expression patterns of TRAF4 and TRAF6 in patients with IBD. The results indicate that TRAF4 and TRAF6 are overexpressed in IBD. TRAF4 and TRAF6 play different roles in the pathogenesis of IBD. Moreover, TRAF4 may be an indicator of endoscopic disease activity of UC and TRAF6 preactivation can be detected in noninflamed colonic segments.
In vivo detection of carboxylic/amide carbons is a promising technique for studying cerebral metabolism and neurotransmission due to the very low RF power required for proton decoupling. In the carboxylic/amide region, however, there is severe spectral overlap between acetate C1 and glutamate C5, complicating studies that use acetate as an astroglia-specific substrate. There are no known in vivo MRS techniques that can spectrally resolve acetate C1 and glutamate C5 singlets. In this study, we propose to spectrally separate acetate C1 and glutamate C5 by a two-step J-editing technique after introducing homonuclear 13C-13C scalar coupling between carboxylic/amide carbons and aliphatic carbons. By infusing [1,2-13C2]acetate instead of [1-13C]acetate the acetate doublet can be spectrally edited because of the large separation between acetate C2 and glutamate C4 in the aliphatic region. This technique can be applied to studying acetate transport and metabolism in brain in the carboxylic/amide region without spectral interference.
In vivo 13C MRS; carboxylic/amide spectral region; acetate metabolism; spectral editing
Objective: TRAF3 and TRAF5 share a common ancestral gene, and interact as essential components of signaling pathways in immunity. TRAF3 and TRAF5 are overexpressed in the colon of rat/mouse models with colitis. However, the expressions of TRAF3 and TRAF5 in patients with inflammatory bowel disease have not been elucidated. The aim of the present study is to explore the potential roles of TRAF3 and TRAF5 in patients with inflammatory bowel disease.
Methods: Plasma levels of TRAF3 and TRAF5 proteins were detected by Enzyme-linked Immunosorbent Assay (ELISA). Colonic expression of TRAF3 and TRAF5 proteins was detected by western blot analysis. Quantitative Real-time PCR (qRT-PCR) was applied for gene expression. Inflamed intestinal mucosa and non-inflamed intestinal mucosa in patients with inflammatory bowel disease and normal mucosa was analyzed from healthy controls.
Results: The plasma levels of TRAF3 and TRAF5 were significantly higher both in patients with Crohn's disease and ulcerative colitis than in healthy controls. Only soluble TRAF5 showed a weak correlation with endoscopic disease activity index (Baron score) in patients with ulcerative colitis (spearman's r=0.358, P=0.022). Gene expressions of TRAF3 and TRAF5 in peripheral blood mononuclear cells were significantly higher both in patients with Crohn's disease and ulcerative colitis than in healthy controls (all P<0.0001). Gene and protein expressions of TRAF3 and TRAF5 were significantly higher in inflamed colonic mucosa of patients with Crohn's disease and ulcerative colitis than in non-inflamed colonic mucosa and normal mucosa of healthy controls (all P<0.0001). Furthermore, gene and protein expressions of TRAF3 and TRAF5 were also significantly higher in non-inflamed colonic mucosa of patients with Crohn's disease and ulcerative colitis than in normal mucosa of healthy controls.
Conclusions: TRAF3 and TRAF5 are overexpressed in inflammatory bowel disease. Although the endoscopic appearance can be normal, TRAF3 and TRAF5 pre-activation can be detected in non-inflamed colonic segments.
TRAF3; TRAF5; Crohn's disease; Ulcerative colitis.
Glutamate is the principal excitatory neurotransmitter in brain. Although it is rapidly synthesized from glucose in neural tissues the biochemical processes for replenishing the neurotransmitter glutamate after glutamate release involve the glutamate–glutamine cycle. Numerous in vivo
13C magnetic resonance spectroscopy (MRS) experiments since 1994 by different laboratories have consistently concluded: (1) the glutamate–glutamine cycle is a major metabolic pathway with a flux rate substantially greater than those suggested by early studies of cell cultures and brain slices; (2) the glutamate–glutamine cycle is coupled to a large portion of the total energy demand of brain function. The dual roles of glutamate as the principal neurotransmitter in the CNS and as a key metabolite linking carbon and nitrogen metabolism make it possible to probe glutamate neurotransmitter cycling using MRS by measuring the labeling kinetics of glutamate and glutamine. At the same time, comparing to non-amino acid neurotransmitters, the added complexity makes it more challenging to quantitatively separate neurotransmission events from metabolism. Over the past few years our understanding of the neuronal-astroglial two-compartment metabolic model of the glutamate–glutamine cycle has been greatly advanced. In particular, the importance of isotopic dilution of glutamine in determining the glutamate–glutamine cycling rate using [1−13C] or [1,6-13C2] glucose has been demonstrated and reproduced by different laboratories. In this article, recent developments in the two-compartment modeling of the glutamate–glutamine cycle are reviewed. In particular, the effects of isotopic dilution of glutamine on various labeling strategies for determining the glutamate–glutamine cycling rate are analyzed. Experimental strategies for measuring the glutamate–glutamine cycling flux that are insensitive to isotopic dilution of glutamine are also suggested.
glutamate; glutamine; magnetic resonance spectroscopy; glucose metabolism; CNS; metabolic modeling; acetate
This paper investigates finite-time synchronization of an array of coupled neural networks via discontinuous controllers. Based on Lyapunov function method and the discontinuous version of finite-time stability theory, some sufficient criteria for finite-time synchronization are obtained. Furthermore, we propose switched control and adaptive tuning parameter strategies in order to reduce the settling time. In addition, pinning control scheme via a single controller is also studied in this paper. With the hypothesis that the coupling network topology contains a directed spanning tree and each of the strongly connected components is detail-balanced, we prove that finite-time synchronization can be achieved via pinning control. Finally, some illustrative examples are given to show the validity of the theoretical results.
Neural networks; Finite-time synchronization; Discontinuous control; Pinning control
We present a rare case of dysembryoplastic neuroepithelial tumor, a rare benign glioneuronal tumor of the central nervous system. It generally occurs in the supratentorial region and the temporal cerebral cortex in children and young adults. The most common presentation is epilepsy. The supratentorial tumor without any signs of mass effect or peritumoral edema is the conventionally accepted diagnostic criteria. In this case of a 19-year-old male with intractable epilepsy, atypical features such as the location of the tumor and the presence of mass effect and peritumoral edema made imaging diagnosis difficult. Diagnosis was confirmed through histopathology. Due to its recent discovery and relatively rare occurrence it is important for radiologists to recognize this disease entity.
DNET; dysembryoplastic neuroepithelial tumor; epilepsy; magnetic resonance imaging
To propose a strategy for reducing RF power deposition by stochastic proton decoupling based on Rayleigh’s theorem.
Materials and Methods
Rayleigh’s theorem was used to remove frequency components of stochastic decoupling over the 3.90–6.83 ppm range. [2-13C] or [2,5-13C2]glucose was infused intravenously to anesthetized rats. 13C labeling of brain metabolites was detected in the carboxylic/amide spectral region at 11.7 Tesla using either the original stochastic decoupling method developed by Ernst or the proposed windowed stochastic decoupling method.
By restricting frequency components of stochastic decoupling to 1.91–3.90 ppm and 6.83–7.60 ppm spectral regions decoupling power deposition was reduced by ~50%. The proposed windowed stochastic decoupling scheme is experimentally demonstrated for in vivo 13C MRS of rat brain at 11.7 Tesla.
The large reduction in decoupling power deposition makes it feasible to perform stochastic proton decoupling at very high magnetic fields for human brain 13C MRS studies.
In vivo 13C MRS; carboxylic/amide carbons; stochastic decoupling scheme; RF power deposition
Amino-acid neurotransmitter system dysfunction plays a major role in the pathophysiology of major depressive disorder (MDD). We used proton magnetic resonance spectroscopy (1H-MRS) to investigate whether prefrontal levels of amino-acid neurotransmitters predict antidepressant response to a single intravenous infusion of the N-methyl-D-aspartate (NMDA) antagonist ketamine in MDD patients. Fourteen drug-free patients with MDD were scanned 1–3 d before receiving a single intravenous infusion of ketamine (0.5 mg/kg). We measured gamma aminobutyric acid (GABA), glutamate, and Glx/glutamate ratio (a surrogate marker of glutamine) in the ventromedial prefrontal cortex (VM-PFC) and the dorsomedial/dorsal anterolateral prefrontal cortex (DM/DA-PFC). Correlation analyses were conducted to determine whether pretreatment GABA, glutamate, or Glx/glutamate ratio predicted change in depressive and anxiety symptoms 230 min after ketamine administration. Pretreatment GABA or glutamate did not correlate with improved depressive symptoms in either of the two regions of interest (p>0.1) ; pretreatment Glx/glutamate ratio in the DM/DA-PFC was negatively correlated with improvement in depressive symptoms [rs(11)=−0.57, p<0.05]. Pretreatment glutamate levels in the VM-PFC were positively correlated with improvement in anxiety symptoms [rs(11)=0.57, p<0.05]. The findings suggest an association between lower Glx/glutamate ratio and greater improvement in response to ketamine treatment. Because glutamine is mainly contained in glia, the decreased Glx/glutamate ratio observed in this study may reflect the reduction in glial cells found in the same regions in post-mortem studies of individuals with MDD, and suggests that the presence of this neuropathological construct may be associated with antidepressant responsiveness to ketamine.
biomarkers; glutamate; glutamine; magnetic resonance spectroscopy (MRS); major depressive disorder (MDD)
The purpose of this prospective study was to evaluate the value of the combined use of MR imaging and multi-slice spiral CT for limb salvage surgery in orthopaedic oncology patients.
Patients and methods
Nine consecutive patients with lower/upper limb malignant bone tumours (7 osteosarcomas and 2 chondrosarcomas) were treated with limb-salvaging procedures. Preoperative planning including determination of the osteotomy plane and diameters of the prosthesis was performed basing on the preoperative CT and MR images. The histopathology was performed as golden diagnostic criteria to evaluate the accuracy of CT and MR-based determination for tumour’s boundary.
The tumour extension measured on MRI was consistent with the actual extension (P>0.05, paired Student’s t test), while the extension measured on CT imaging was less than the actual extension. The length, offset and alignment of the affected limb were reconstructed accurately after the operation. An excellent functional outcome was achieved in all patients.
In the present study, MRI was found to be superior to CT for determining the tumour extension, combined use of MRI and CT measurement provided high precision for the fit of the prosthesis and excellent functional results.
limb salvage surgery; magnetic resonance imaging (MRI); computed tomography (CT)
In the present study, in vivo 13C magnetic resonance spectroscopy (MRS) was used to study the labeling of brain metabolites after intravenous administration of [1-13C]ethanol. After [1-13C]ethanol was systemically administrated to the rats, 13C labels were detected in glutamate, glutamine and aspartate in the carboxylic and amide carbon spectral region. 13C-labeled bicarbonate HCO3− (161.0 ppm) was also detected. Saturating acetaldehyde C1 at 207.0 ppm was found to have no effect on the ethanol C1 (57.7 ppm) signal intensity after extensive signal averaging, providing direct in vivo evidence that direct metabolism of alcohol by brain tissue is minimal. To compare the labeling of brain metabolites by ethanol with labeling by glucose, in vivo time course data were acquired during intravenous co-infusion of [1-13C]ethanol and [13C6]-D-glucose. In contrast to labeling by [13C6]-D-glucose which produced doublets of carboxylic/amide carbons with a J coupling constant of 51 Hz, the simultaneously detected glutamate and glutamine singlets are labeled by [1-13C]ethanol. Since 13C labels originated from ethanol enter brain after being converted into [1-13C]acetate in liver and the direct metabolism of ethanol by brain tissue is negligible, it is suggested that orally or intragastrically administered 13C-labeled ethanol may be used to study brain metabolism and glutamatergic neurotransmission in studies involving alcohol administration. In vivo 13C MRS of rat brain following intragastric administration of 13C-labeled ethanol is demonstrated.
in vivo13C MRS; ethanol; acetate; cerebral metabolism
A new spectral localization technique for in vivo magnetic resonance spectroscopy (MRS) is introduced. Structural information extracted from anatomical imaging is utilized for defining compartments which provide the basis for spectral localization. Inherent spatial heterogeneity of multiple receiver coil elements is used along with optional phase encoding to resolve signals from different compartments. This technique allows a few compartmental spectra to be reconstructed from multi-channel data acquired with no or very few phase encoding steps, resulting in short scan time and high efficiency. Alternatively, this technique also allows a significant number of compartmental spectra to be reconstructed if sufficient phase encoding steps are used. A procedure is developed to semi-automatically generate a significant number of compartments of comparable sizes, which allows one to obtain spectra from small regions of interest with curvilinear shapes. This may be useful for obtaining spectra from relatively small stroke lesions or tumors. Phantom experiments and in vivo MRS of stroke patients have been performed to demonstrate this technique.
MRS; CSI; SLIM; stroke; tumor
Rheumatoid arthritis (RA) is a chronic inflammatory disease leading to joint destruction and disability. Focal bone erosion is due to excess bone resorption of osteoclasts. Tumor necrosis factor receptor-associated factor 6 (TRAF6) is one of the critical mediators both in inflammatory signal pathway and differentiation and resorption activity of osteoclasts. Here we aimed to investigate TRAF6 expression in RA synovium and its correlation with histological synovitis severity and radiological joint destruction in RA.
Synovitis score was determined in needle biopsied synovium from 44 patients with active RA. Synovium from nine patients with osteoarthritis (OA) and seven with orthopedic arthropathies (Orth.A) were enrolled as "less inflamed" disease controls. Serial sections were stained immunohistochemically for TRAF6 as well as CD68 (macrophage), CD3 (T cell), CD20 (B cell), CD38 (plasmocyte), CD79a (B lineage cells from pre-B cell to plasmocyte stage), and CD34 (endothelial cell). Double immunofluorescence staining of TRAF6 and CD68 were tested. Densities of positive staining cells were determined and correlated with histological disease activity (synovitis score) and radiographic joint destruction (Sharp score).
TRAF6 expression was found in the intimal and subintimal area of RA synovium, with intense staining found in the endochylema and nucleus of intimal synoviocytes and subintimal inflammatory cells. Double immunofluorescence staining showed TRAF6 was expressed in most of the intimal cells and obviously expressed in CD68+ cells and some other CD68- cells in subintimal area. Synovial TRAF6 was significantly over-expressed in the RA group compared with the OA and Orth.A group (2.53 ± 0.94 vs. 0.72 ± 0.44 and 0.71 ± 0.49, P < 0.0001). Synovial TRAF6 expression in RA correlated significantly with synovitis score (r = 0.412, P = 0.006), as well as the inflammatory cell infiltration (r = 0.367, P = 0.014). Significant correlation was detected between synovial TRAF6 expression and intimal CD68+ cells, as well as the cell density of subintimal CD68+ cells, CD3+ cells, CD20+ cells, CD38+ cells, and CD79a+ cells (all P < 0.05).
Elevated synovial TRAF6 expression correlated with synovitis severity and CD68+ cell density in RA. It is, therefore, hypothesized that synovial TRAF6 is involved in the pathogenesis of synovial inflammation and osteoclast differentiation in RA.
In this report a new method is introduced for simultaneous detection of the metabolism of two 13C-labeled subtracts in brain in vivo. We recognized and experimentally demonstrated that when a 13C-labeled substrate generates [1,2-13C2]acetylCoA ([1-13C]acetylCoA) only, glutamate C5, glutamine C5 and apsartate C4 doublets (singlets) are formed exclusively, regardless of the number of turns of the tricarboxylic acid cycle. We utilized the large one-bond 13C-13C homonuclear J coupling between a carboxylic/amide carbon and an aliphatic carbon (~50 Hz) and demonstrated that it is feasible to simultaneously detect the labeling of brain metabolites by two different substrates using different isotopomer signals of the same carbon atom. Uniformly labeled glucose was used to generate the doublets and a second substrate ([2-13C] lactate or [1,3-13C2]β-hydroxybutyrate or [1-13C] acetate) was used to generate the singlets. It was shown that contribution to cerebral metabolism from different substrates can be simultaneously measured in vivo.
cerebral energy metabolism; in vivo 13C MRS; carboxylic/amide spectral region; ketone body; lactate
Adiabatic pulses are widely used for spatial localization in magnetic resonance spectroscopy because of their high immunity to RF inhomogeneity and excellent slice profiles. Since non-rectangular volume is often preferred in localized spectroscopy, we propose a scheme for selecting a trapezoidal slice using adiabatic π pulses. In this scheme, a time-varying gradient orthogonal to a stationary slice-selection gradient is used to change the boundaries of the slice profile from parallel to non-parallel. Numerical simulation results for the transverse and longitudinal magnetization using different RF and gradient waveforms are presented for non-parallel slice selection. Phantom imaging and in vivo 1H MRS of rat brain using nonparallel slices are demonstrated.
adiabatic pulse; non-rectangular volume selection; time-varying gradient
Attentional dysfunction is one of the most consistent findings in individuals with autism spectrum disorders (ASD). However, the significance of such findings for the pathophysiology of autism is unclear. In this study, we investigated cellular neurochemistry with proton magnetic resonance spectroscopy imaging (1H-MRS) in brain regions associated with networks subserving alerting, orienting, and executive control of attention in patients with ASD. Concentrations of cerebral N-acetyl-aspartate (NAA), creatinine + phosphocreatinine, choline-containing compounds, myo-inositol (Ins) and glutamate + glutamine (Glx) were determined by 3 T 1H-MRS examinations in 14 high-functioning medication-free adults with a diagnosis of ASD and 14 age- and IQ-matched healthy controls (HC) in the anterior cingulate cortex (ACC), thalamus, temporoparietal junction (TPJ), and areas near or along the intraparietal sulcus (IPS). Compared to HC group, the ASD group showed significantly lower Glx concentrations in right ACC and reduced Ins in left TPJ. This study provides evidence of abnormalities in neurotransmission related to networks subserving executive control and alerting of attention, functions which have been previously implicated in ASD pathogenesis.
autism; spectroscopy; glutamate; anterior cingulate cortex; intraparietal sulcus; myo-inositol
Osteoarthritis (OA) is a degenerative joint disease that affects both cartilage and bone. A better understanding of the early molecular changes in subchondral bone may help elucidate the pathogenesis of OA. We used microarray technology to investigate the time course of molecular changes in the subchondral bone in the early stages of experimental osteoarthritis in a rat model. We identified 2,234 differentially expressed (DE) genes at 1 week, 1,944 at 2 weeks and 1,517 at 4 weeks post-surgery. Further analyses of the dysregulated genes indicated that the events underlying subchondral bone remodeling occurred sequentially and in a time-dependent manner at the gene expression level. Some of the identified dysregulated genes that were identified have suspected roles in bone development or remodeling; these genes include Alp, Igf1, Tgf β1, Postn, Mmp3, Tnfsf11, Acp5, Bmp5, Aspn and Ihh. The differences in the expression of these genes were confirmed by real-time PCR, and the results indicated that our microarray data accurately reflected gene expression patterns characteristic of early OA. To validate the results of our microarray analysis at the protein level, immunohistochemistry staining was used to investigate the expression of Mmp3 and Aspn protein in tissue sections. These analyses indicate that Mmp3 protein expression completely matched the results of both the microarray and real-time PCR analyses; however, Aspn protein expression was not observed to differ at any time. In summary, our study demonstrated a simple method of separation of subchondral bone sample from the knee joint of rat, which can effectively avoid bone RNA degradation. These findings also revealed the gene expression profiles of subchondral bone in the rat OA model at multiple time points post-surgery and identified important DE genes with known or suspected roles in bone development or remodeling. These genes may be novel diagnostic markers or therapeutic targets for OA.
NRG1-ErbB4 signaling controls inhibitory circuit development in the mammalian cortex through ErbB4 dependent regulation of GABAergic interneuron connectivity. Common genetic variation in ErbB4 (rs7598440) has been associated with ErbB4 messenger RNA levels in the human cortex and risk for schizophrenia. Recent work demonstrates that Erbb4 is expressed exclusively on inhibitory interneurons, where its presence on parvalbumin positive cells mediates the effects of NRG1 on inhibitory circuit formation in the cortex. We therefore hypothesized that genetic variation in ErbB4 at rs7598440 would impact indices of GABA concentration in the human cortex. We tested this hypothesis in 116 healthy volunteers by measuring GABA and GLX (glutamate + glutamine) with proton magnetic resonance spectroscopy (MRS) in the dorsal anterior cingulate gyrus. ErbB4 rs7598440 genotype significantly predicted cortical GABA concentration (p=0.014), but not GLX (p=0.51), with A allele carriers having higher GABA as predicted by their impact on ErbB4 expression. These data establish an association of ErbB4 and GABA in human brain and have implications for understanding the pathogenesis of schizophrenia and other psychiatric disorders.
Glutamate; NAA; Creatine; Anterior Cingulate; white matter; gray matter; MRS; 3 Tesla