Prediction of novel biomarkers for gastric intestinal metaplasia and gastric adenocarcinoma using bioinformatics analysis

Background & aim

The histologic and molecular changes from intestinal metaplasia (IM) to gastric cancer (GC) have not been fully characterized. The present study sought to identify potential alterations in signaling pathways in IM and GC to predict disease progression; these alterations can be considered therapeutic targets.

Materials & methods

Seven gene expression profiles were selected from the GEO database. Discriminate differentially expressed genes (DEGs) were analyzed by EnrichR. The STRING database, Cytoscape, Gene Expression Profiling Interactive Analysis (GEPIA), cBioPortal, NetworkAnalyst, MirWalk database, OncomiR, and bipartite miRNA‒mRNA correlation network was used for downstream analyses of selected module genes.

Results

Analyses revealed that extracellular matrix-receptor interactions (ITGB1, COL1A1, COL1A2, COL4A1, FN1, COL6A3, and THBS2) in GC and PPAR signaling pathway interactions (FABP1, APOC3, APOA1, HMGCS2, and PPARA and PCK1) in IM may play key roles in both the carcinogenesis and progression of underlying GC from intestinal metaplasia. IM enrichment indicated that this is closely related to digestion and absorption. The TF-hub gene regulatory network revealed that AR, TCF4, SALL4, and ESR1 were more important for hub gene expression. It was revealed that the development and prediction of GC may be affected by hsa-miR-29. It was found that PTGR1, C1orf115, CRYL1, ALDOB, and SULT1B1 were downregulated in GC and upregulated in IM. Therefore, they might have tumor suppressor activity in GC progression.

Conclusion

New potential biomarkers and pathways involved in GC and IM were identified that are important for the transformation of GC from IM to adenocarcinoma and can be therapeutic targets for GC.

Parameter Space and Potential for Biomarker Development in 25 Years of fMRI Drug Cue Reactivity: A Systematic Review

Importance

In the last 25 years, functional magnetic resonance imaging drug cue reactivity (FDCR) studies have characterized some core aspects in the neurobiology of drug addiction. However, no FDCR-derived biomarkers have been approved for treatment development or clinical adoption. Traversing this translational gap requires a systematic assessment of the FDCR literature evidence, its heterogeneity, and an evaluation of possible clinical uses of FDCR-derived biomarkers.

Objective

To summarize the state of the field of FDCR, assess their potential for biomarker development, and outline a clear process for biomarker qualification to guide future research and validation efforts.

Evidence Review

The PubMed and Medline databases were searched for every original FDCR investigation published from database inception until December 2022. Collected data covered study design, participant characteristics, FDCR task design, and whether each study provided evidence that might potentially help develop susceptibility, diagnostic, response, prognostic, predictive, or severity biomarkers for 1 or more addictive disorders.

Findings

There were 415 FDCR studies published between 1998 and 2022. Most focused on nicotine (122 [29.6%]), alcohol (120 [29.2%]), or cocaine (46 [11.1%]), and most used visual cues (354 [85.3%]). Together, these studies recruited 19 311 participants, including 13 812 individuals with past or current substance use disorders. Most studies could potentially support biomarker development, including diagnostic (143 [32.7%]), treatment response (141 [32.3%]), severity (84 [19.2%]), prognostic (30 [6.9%]), predictive (25 [5.7%]), monitoring (12 [2.7%]), and susceptibility (2 [0.5%]) biomarkers. A total of 155 interventional studies used FDCR, mostly to investigate pharmacological (67 [43.2%]) or cognitive/behavioral (51 [32.9%]) interventions; 141 studies used FDCR as a response measure, of which 125 (88.7%) reported significant interventional FDCR alterations; and 25 studies used FDCR as an intervention outcome predictor, with 24 (96%) finding significant associations between FDCR markers and treatment outcomes.

Conclusions and Relevance

Based on this systematic review and the proposed biomarker development framework, there is a pathway for the development and regulatory qualification of FDCR-based biomarkers of addiction and recovery. Further validation could support the use of FDCR-derived measures, potentially accelerating treatment development and improving diagnostic, prognostic, and predictive clinical judgments.

Evaluation of multimodal MR imaging for differentiating infiltrative versus reactive edema in brain gliomas

OBJECTIVE

To determine the border of glial tumors by diffusion weighted imaging (DWI), apparent diffusion co-efficient (ADC), magnetic resonance spectroscopy (MRS) and perfusion brain MRI.

PATIENTS AND METHODS

Ten patients with brain gliomas were enrolled [mean age: 35.3 ± 13.2, range: 20-62]. Conventional MRI was performed for all patients. Besides, tumor mapping based on Choline (Cho)/Creatine (Cr) color map in MRS, perfusion and diffusion color maps, were gathered. Different tumoral and peritumoral regions [normal tissue, reactive edema, infiltrative edema, and tumor core] were defined. MRI criteria were evaluated in areas targeted for biopsy and histopathologic evaluation was determined.

RESULTS

Tumor cell positive samples [one necrosis, 26 infiltrative and nine tumor cores] composed 36 (75%) of the 48 samples. Seven (19.4%) of the positive samples were interpreted as not tumor on MRI. Five were identified as reactive edema and two as normal tissue] [kappa: .67, p-value < .001]. Mean of ADC, median of N-acetylaspartate (NAA) and NAA/Cho were statistically different between positive and negative samples (p = .02 and p < .001, respectively). Mean ADC and median Cho/NAA were statistically different in missed tumor containing tissue presented as reactive edema compared to normal and correctly diagnosed reactive edema samples together (p-values < .05).

CONCLUSIONS

Multimodal MRI could define infiltrated borders of brain gliomas.

DLPFC stimulation alters large-scale brain networks connectivity during a drug cue reactivity task: A tDCS-fMRI study

Transcranial direct current stimulation (tDCS) is a promising intervention for reducing craving/consumption in individuals with substance use disorders. However, its exact mechanism of action has not yet been well explored. We aimed to examine the network-based effects of tDCS while people with methamphetamine use disorders (MUDs) were exposed to drug cues. In a randomized, double-blind sham-controlled trial with a crossover design, 15 participants with MUDs were recruited to receive 20 min of active/sham tDCS with an anode/cathode over F4/F3. MRI data, including structural and task-based functional MRI during a standard drug cue-reactivity task, were collected immediately before and after stimulation sessions. Craving scores were also recorded before and after MRI scans. Individualized head models were generated to determine brain regions with strong electric fields (EFs). Using atlas-based parcellation of head models, averaged EFs were extracted from the main nodes of three large-scale networks that showed abnormalities in MUDs; executive control (ECN), default mode (DMN), and ventral attention (VAN) networks. Main nodes with high EF intensity were used as seed regions for task-based functional connectivity (FC) [using generalized psychophysiological interaction (gPPI)] and activity [using a general linear model (GLM)] calculations. Subjective craving showed a significant reduction in immediate craving after active (-15.42 ± 5.42) compared to sham (-1 ± 2.63). In seed-to-whole brain results, the PFC node in ECN showed an enhanced PPI connectivity with precuneus and visual cortex; the cluster center in MNI (6, -84, -12); the PFC node in DMN showed a decreased PPI connectivity with contralateral parietal cortex;(-48, -60, 46). ROI-to-ROI results showed increased PPI connectivity within/between ECN-VAN while connectivity between ECN-DMN decreased. In line with connectivity, functional activity in the right PFC node in DMN decreased after tDCS while activity in PFC nodes of ECN/VAN increased. EF calculations in PFC nodes revealed that EF in DMN was outward, while the direction of EFs was inward in ECN/VAN. This study provides new insight into neural circuitry underlying MUDs that can be modulated by tDCS at the network level and specifically suggests that bilateral tDCS increases cortical excitability in ECN and VAN, while it has opposite effects on DMN that may be related to the direction of EFs.

A case report of the sustained and rapid response of bevacizumab in a TP53-positive breast cancer and liver metastatic patient through personalized medicine

HER2-positive metastatic breast cancer is much less frequent than other subgroups of breast cancer. Treatment options for this cancer are mostly limited to systemic chemotherapy, which leads to moderate improvements. Targeted therapy against malignant breast cancer requires the identification of reliable biomarkers for personalized medicine to obtain the maximum benefit of this therapy. Any mutations in the TP53 signaling pathway can be considered as a significant causative factor of breast cancer, for which the identification of target genes plays an important role in selecting the appropriate treatment. The use of personalized gene expression profiling could be valuable to find the direct target of the treatment in this case. The present study assessed the genetic profile of an HER2-positive metastatic breast cancer patient (with a liver metastasis) and figured out a complete and sustained response to bevacizumab. According to the results of next-generation sequencing (NGS) analysis, the patient’s genetic profile showed an increased expression of p4EBP1 and PTEN and the activation of the mTOR signaling pathway with a mutation in the TP53 gene. Based on the common treatment of similar profiling, we administrated bevacizumab/Taxol/Gemzar chemotherapy up to six courses. Accordingly, as the response to treatment was revealed by reducing the volume of the liver metastasis from 4 to 1.4 cm, metastasectomy was performed as a complementary treatment. Hence, personalized gene expression profiling not only is useful for targeted therapy but also could be recommended to avoid prescription of non-responsive drugs.

Cue-induced craving and negative emotion disrupt response inhibition in methamphetamine use disorder: Behavioral and fMRI results from a mixed Go/No-Go task

BACKGROUND

Drug-related cue-reactivity, dysfunctional negative emotion processing, and response-disinhibition constitute three core aspects of methamphetamine use disorder (MUD). These phenomena have been studied independently, but the neuroscientific literature on their interaction in addictive disorders remains scant.

METHODS

62 individuals with MUD were scanned when responding to the geometric Go or No-Go cues superimposed over blank, neutral, negative-emotional and drug-related background images. Neural correlates of drug and negative-emotional cue-reactivity, response-inhibition and their interactions were estimated, and methamphetamine cue-reactivity was compared between individuals with MUD and 23 healthy controls. Relationships between behavioral characteristics and observed activations were investigated.

RESULTS

Individuals with MUD had longer reaction times and more errors in drug and negative-emotional compared to blank blocks, and more omission errors in drug compared to neutral blocks. They showed higher drug cue-reactivity than controls across prefrontal, fusiform, and visual regions (Z > 3.1, p-corrected<0.05). Response-inhibition was associated with precuneal, inferior parietal, anterior cingulate, temporal, and inferior frontal activations (Z > 3.1, p-corrected<0.05). Response-inhibition in drug cue blocks coincided with higher activations in the visual cortex and lower activations in the paracentral lobule and superior and inferior frontal gyri, while inhibition during negative-emotional blocks led to higher superior parietal, fusiform, and lateral occipital activations (Z > 3.1, p-corrected<0.05).

CONCLUSION

Drug cue-reactivity may impair response inhibition partly through activating dis-inhibitory regions, while temporal and parietal activations associated with response-inhibition in negative blocks suggest compensatory activity. Results suggest that drug and negative-emotional cue-reactivity influence response-inhibition, and the study of these interactions may aid mechanistic understanding of methamphetamine use disorder.

Magnetic resonance imaging of tumor-infiltrating lymphocytes by anti-CD3-conjugated iron oxide nanoparticles

Immune checkpoint blockade, considered a revolutionary approach in cancer treatment, is only effective in patients with high tumor-infiltrating lymphocytes (TILs). This work aimed to investigate the feasibility of targeted contrast agent (CA) based on dextran-coated superparamagnetic iron oxide nanoparticles (SPIONs-DEX) for TILs detection by magnetic resonance imaging (MRI) studies. To do so, we synthesized an MRI CA by conjugating SPIONs-DEX to an anti-CD3 monoclonal antibody via cyanogen bromide as a cross-linker. In vitro assessments demonstrated the higher labeling efficiency of the developed CA to CD3+ lymphocytes compared to SPIONs-DEX. In vivo MRI of a xenograft model of CD3+ lymphocytes revealed the significant signal loss after the intravenous injection of the bioconjugate by ~ 34% and 21% in T 2 * -weighted and T 2 -weighted images, respectively. The histopathological evaluation of xenograft tumors confirmed the labeling of lymphocytes by the targeted CA. This approach could open up a new horizon in the non-invasive assessment of TILs to identify patients eligible for immunotherapy.

Quantification of Blood-Brain-Barrier Permeability Dysregulation and Inflammatory Activity in MS Lesions by Dynamic-Contrast Enhanced MR Imaging

Introduction

Introduction: blood-brain-barrier perfusion characterization impaired in MS as some studies have shown recently but a comparison between perfusion parameters in contrast-enhanced and non-enhanced lesions not have been well documented. Pharmacokinetic quantitative parameters have obtained from dynamic contrast-enhanced in magnetic resonance imaging is a useful way to quantify blood-brain barrier permeability leakage.

Methods

MR examination was performed on 28 patients with Relapsing-remitted Multiple Sclerosis (RRMS) with (Mean±SD age: 34.7±9.28) which had multiple lesions in the brain.3D dynamic T1-weighted spoiled gradient echo was obtained and Perfusion parameters and its map assessed in enhanced and non-enhanced lesions after intravascular injection differences in parameters and map obtained by analyzing ROI in Extended Toft model.

Results

permeability as measured Krtans was a significantly higher value in CE to compare NE lesions. Ktrans and Kep have significant differences in NAWM and CE and NE lesions. Vb was slightly different in NE and CE lesions.

Conclusion

Permeability measured as Ktrans was the good parameter to show permeability impairment of BBB in CE lesions. Dysregulation in BBB is an acceptable sign to indicate existence inflammation in CE lesions.

Highlights

Multiple Sclerosis,Inflammation,Blood-brain-barrier dysregulation.

Plain Language Summary

Inflammation activity in MS patients has an important role to cause BBB dysfunction.in this article to achieve results to confirm the inflammation importance in MS patients with acute lesions. MRI modality have been used and with comparison between acute and chronic lesions and NAWM of MS patient's presence of inflammation have been proved.

White matter microstructure differences in individuals with dependence on cocaine, methamphetamine, and nicotine: Findings from the ENIGMA-Addiction working group

BACKGROUND

Nicotine and illicit stimulants are very addictive substances. Although associations between grey matter and dependence on stimulants have been frequently reported, white matter correlates have received less attention.

METHODS

Eleven international sites ascribed to the ENIGMA-Addiction consortium contributed data from individuals with dependence on cocaine (n = 147), methamphetamine (n = 132) and nicotine (n = 189), as well as non-dependent controls (n = 333). We compared the fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD) and mean diffusivity (MD) of 20 bilateral tracts. Also, we compared the performance of various machine learning algorithms in deriving brain-based classifications on stimulant dependence.

RESULTS

The cocaine and methamphetamine groups had lower regional FA and higher RD in several association, commissural, and projection white matter tracts. The methamphetamine dependent group additionally showed lower regional AD. The nicotine group had lower FA and higher RD limited to the anterior limb of the internal capsule. The best performing machine learning algorithm was the support vector machine (SVM). The SVM successfully classified individuals with dependence on cocaine (AUC = 0.70, p < 0.001) and methamphetamine (AUC = 0.71, p < 0.001) relative to non-dependent controls. Classifications related to nicotine dependence proved modest (AUC = 0.62, p = 0.014).

CONCLUSIONS

Stimulant dependence was related to FA disturbances within tracts consistent with a role in addiction. The multivariate pattern of white matter differences proved sufficient to identify individuals with stimulant dependence, particularly for cocaine and methamphetamine.

Along-tract analysis of the white matter is more informative about brain ageing, compared to whole-tract analysis

Diffusion Tensor Imaging (DTI) enabled the investigation of brain White Matter (WM), both qualitatively to study the macrostructure, and quantitatively to study the microstructure. The quantitative analyses are mostly performed at the whole-tract level, i.e., providing one measure of interest per tract; however, along-tract approaches may provide finer details of the quality of the WM tracts. In this study, using the DWI data collected from 40 young and 40 old individuals, we compared the DTI measures of FA, MD, AD, and RD, estimated by both whole-tract and along-tract approaches in 18 WM bundles, between the two groups. The results of the whole-tract quantitative analysis showed a statistically significant (p-FWER < 0.05) difference between the old and young groups in 6 tracts for FA, 8 tracts for MD, 1 tract for AD, and 7 tracts for RD. On the contrary, the along-tract approach showed differences between the two groups in 10 tracts for FA, 14 tracts for MD, 8 tracts for AD, and 11 tracts for RD. All the differences between the along-tract measures of the two groups had a large effect size (Cohen'd > 0.80). This study showed that the along-tract approach for the analysis of brain WM reveals changes in some WM tracts which had not shown any changes in the whole-tract approach, and therefore this finding emphasizes the utilization of the along-tract approach along with the whole-tract method for a more accurate study of the brain WM.

Temporal Dynamics of the Neural Response to Drug Cues: An fMRI Study among Methamphetamine Users

Objective: Cue-induced craving is central to addictive disorders. Most cue-reactivity fMRI studies are analysed statically and report averaged signals, disregarding the dynamic nature of craving and task fatigue. Methods: Thirty-two early abstinent methamphetamine users underwent fMRI-scanning while viewing visual methamphetamine cues. A Craving>Neutral contrast was obtained in regions of interest. To explore changes over time, the pre-processed signal was divided into three intervals. Contrast estimates were calculated within each interval, and were compared using ANOVA followed by post hoc t-tests. The results were compared with those from a static analysis across all blocks. Results: A priori expected activations in the prefrontal cortex, insula and striatum not detected by static analysis were discovered by the dynamic analysis. Post hoc tests revealed distinct temporal activation patterns in several regions. Most showed rapid activation (including both ventral/dorsal striata and most regions in the prefrontal, insular and cingulate cortices) whereas some had delayed activation (the right anterior insula, left middle frontal gyrus, and left dorsal anterior cingulate cortex). Conclusions: This study provides preliminary insights into the temporal dynamicity of cue-reactivity, and the potential of a conventional blocked-design task to consider it using a simple dynamic analysis. We highlight regional activations that were only uncovered by a dynamic analysis, and discuss the interesting and theoretically expected early versus late regional activation patterns. Rapidly activated regions are mostly those involved in the earlier stages of cue-reactivity, while regions with later activation participate in cognitive functions relevant later, such as reappraisal, interoception and executive control.

Psychometric Properties of the Persian Version of Patient Health Questionnaire-9

Objectives: The Patient Health Questionnaire-9 (PHQ-9) is one of the most commonly used measures for screening, diagnosing and monitoring of depression. So far, four studies have examined some of the psychometric properties of Persian version of PHQ-9 in physical and psychiatric patients; however, some aspects of its psychometrics have not yet been adequately evaluated in the student population. Therefore, this study aims to examine more psychometric properties of the Persian version of PHQ-9 in the student population. Methods: In this descriptive study, 463 students of Guilan University of Medical Sciences in the academic year 2018-19 participated who were selected using a convenience sampling method. The reliability of the Persian PHQ-9 was assessed using internal consistency and test-retest reliability for a 2-week interval. Its construct validity was evaluated by exploratory and confirmatory factor analyses. To evaluate its convergent validity, the second version of the Beck Depression Inventory (BDI-II), the depression subscale of the 21-item Depression Anxiety Depression Inventory (DASS-21), the neuroticism subscale of NEO Five Factor Inventory (NEO-FFI) and the negative affect subscale of the Positive Affect and Negative Affect Scale (PANAS) were used. The openness subscale of NEO-FFI and the positive affect subscale of PANAS were also used to assess its discriminant validity. Results: Cronbach’s alpha coefficient of 0.856 and intraclass correlation coefficient of 0.869 indicated high internal consistency and test-retest reliability of the Persian PHQ-9, respectively. Exploratory factor analysis results showed a one-factor structure, accounting for 47.59% of the total variance. Confirmatory factor analysis results showed that all questions were related to one factor. Positive correlation of the Persian PHQ-9 score with BDI-II (r= 0.769), the neuroticism subscale of NEO-FFI (r= 0.508), the depression subscale of DASS-21 (r= 0.647) and the negative affect subscale of PANAS (r= 0.430) indicated an acceptable convergent validity, while its negative correlation with the positive affect subscale PANAS (r= -0.444) indicated its acceptable discriminant validity; however, its score had no significant relationship with the openness subscale of NEO indicates NEO-FFI (r= 0.116). Conclusion: The Persian PHQ-9 can be used in clinical and research fields to screen, diagnose, and monitor clinical and/or subclinical depression in the Iranian student population.

An interictal measurement of cerebral oxygen extraction fraction in MRI-negative refractory epilepsy using quantitative susceptibility mapping

PURPOSE

Oxygen extraction fraction (OEF) can be a factor to identify brain tissue's disability in epileptic patients. This study aimed to assess the OEF's level measurement in refractory epileptic patients (REPs) using a quantitative susceptibility mapping (QSM) method and to determine whether the OEF parameters change.

METHODS

QSM-OEF maps of 26 REPs and 16 healthy subjects were acquired using 3T MRI with a 64-channel coil. Eighteen regions-of-interest (ROIs) were chosen around the cortex in one appropriate slice of the brain and the mean QSM-OEF for each ROI was obtained. The correlations of QSM-OEF among different clinical characteristics of the disease, as well as between the patients and normal subjects, were also investigated.

RESULTS

QSM-OEF was shown to be significantly higher in REPs (44.9 ± 5.8) than that in HS (41.9 ± 6.2) (p < 0.05). Mean QSM-OEF was statistically lower in the ipsilateral side (44.5 ± 6.6) compared to the contralateral side (46.4 ± 6.8) (P < 0.01). QSM-OEF was illustrated to have a strong positive correlation with the attack duration (r = 0.6), and a moderate negative correlation with the attack frequency (r = -0.3). Using an optimized support vector machine algorithm, we could predict the disease in subjects having abnormal OEF values in the brain-selected-ROIs with sensitivity, specificity, AUC, and the precision of 0.96, 1, 0.98, and 1, respectively.

CONCLUSIONS

The results of this study revealed that QSM-OEF of the REPs' brain is higher than that of HS, which indicates that QSM-OEF is associated with disease activity.

Iranian Brain Imaging Database: A Neuropsychiatric Database of Healthy Brain

INTRODUCTION

The Iranian Brain Imaging Database (IBID) was initiated in 2017, with 5 major goals: provide researchers easy access to a neuroimaging database, provide normative quantitative measures of the brain for clinical research purposes, study the aging profile of the brain, examine the association of brain structure and function, and join the ENIGMA consortium. Many prestigious databases with similar goals are available. However, they were not done on an Iranian population, and the battery of their tests (e.g. cognitive tests) is selected based on their specific questions and needs.

METHODS

The IBID will include 300 participants (50% female) in the age range of 20 to 70 years old, with an equal number of participants (#60) in each age decade. It comprises a battery of cognitive, lifestyle, medical, and mental health tests, in addition to several Magnetic Resonance Imaging (MRI) protocols. Each participant completes the assessments on two referral days.

RESULTS

The study currently has a cross-sectional design, but longitudinal assessments are considered for the future phases of the study. Here, details of the methodology and the initial results of assessing the first 152 participants of the study are provided.

CONCLUSION

IBID is established to enable research into human brain function, to aid clinicians in disease diagnosis research, and also to unite the Iranian researchers with interests in the brain.

Effect of Physiological Noise on Thoracolumbar Spinal Cord Functional Magnetic Resonance Imaging in 3T Magnetic Field

Introduction:

Functional Magnetic Resonance Imaging (fMRI) methods have been used to study sensorimotor processing in the spinal cord. However, these techniques confront unwanted noises to the measured signal from the physiological fluctuations. In the spinal cord imaging, most of the challenges are consequences of cardiac and respiratory movement artifacts that are considered as significant sources of noise, especially in the thoracolumbar region. In this study, we investigated the effect of each source of physiological noise and their contribution to the outcome of the analysis of the blood-oxygen-level-dependent signal in the human thoracolumbar spinal cord.

Methods:

Fifteen young healthy male volunteers participated in the study, and pain stimuli were delivered on the L5 dermatome between the two malleoli. Respiratory and cardiac signals were recorded during the imaging session, and the generated respiration and cardiac regressors were included in the general linear model for quantification of the effect of each of them on the task-analysis results. The sum of active voxels of the clusters was calculated in the spinal cord in three correction states (respiration correction only, cardiac correction only, and respiration and cardiac noise corrections) and analyzed with analysis of variance statistical test and receiver operating characteristic curve.

Results:

The results illustrated that cardiac noise correction had an effective role in increasing the active voxels (Mean±SD = 23.46±9.46) compared to other noise correction methods. Cardiac effects were higher than other physiological noise sources

Conclusion:

In summary, our results indicate great respiration effects on the lumbar and thoracolumbar spinal cord fMRI, and its contribution to the heartbeat effect can be a significant variable in the individual fMRI data analysis. Displacement of the spinal cord and the effects of this noise in the thoracolumbar and lumbar spinal cord fMRI results are significant and cannot be ignored.

Assessment of the Characteristics of Different Kinds of MS Lesions Using Multi-Parametric MRI

Background: Studying different pathological aspects of lesions in multiple sclerosis (MS) patients could be useful to modify the diagnosis and treatment of this neurological disorder. Magnetic resonance imaging (MRI) modalities have the potential to investigate variations in brain tissue because of inflammatory and neurodegenerative processes in various types of MS-related lesions. Objectives: This study was done to investigate the quantitative changes in MRI-based parameters, like perfusion and magnetization transfer ratio (MTR) of different types of brain lesions, to demonstrate the ability of MRI to detect structural and pathological differences in MS lesions. Methods: Quantitative MRI modalities were performed on 18 patients with five different kinds of lesions (T1 holes, acute and chronic white matter (WM), and acute and chronic gray matter (GM) lesions) using a 3 T MRI scanner. The following protocols were used to characterize the pathology of lesions: (I) fluid-attenuated inversion recovery (FLAIR); (II) pre- and post-contrast T1-weighted; (III) dynamic contrast-enhanced (DCE); and (IV) MTR imaging. Quantitative comparison of Ktrans, cerebral blood volume (CBV), cerebral blood flow (CBF), and MTR was done to find the best parameter to distinguish different lesions. Finally, a multivariate classifier was applied to introduce the best parameter to indicate differences in lesions. Results: Five lesions were characterized by perfusion and MTR parameters. The pathological changes were measured, including: (I) the highest value of parameters in both acute WM and GM lesions; (II) the lowest value of four parameters in both chronic WM and GM lesions; (III) MTR had the highest rank among parameters using the classifier. Conclusions: The degree of pathological alterations due to inflammatory and neurodegenerative processes in MS-related lesions was indicated through the used parameters in different kinds of lesions. Inflammation was the dominant process in acute lesions, while neurodegeneration and tissue loss were observed mostly in chronic lesions. Both inflammation and neurodegeneration were detected in T1 holes. Perfusion parameters and MTR were reasonable parameters to describe differences in brain lesions. Thus, it could be confirmed that magnetization transfer imaging (MTI) and DCE-MRI are high-sensitivity methods to detect microstructural changes in the brain and subtle changes in the blood-brain-barrier. Classification of the parameters indicated that MTR was the best biomarker than others to show variations in lesions pathology.

Fully automatic 3D segmentation of the thoracolumbar spinal cord and the vertebral canal from T2-weighted MRI using K-means clustering algorithm

STUDY DESIGN

Method development.

OBJECTIVES

To develop a reliable protocol for automatic segmentation of Thoracolumbar spinal cord using MRI based on K-means clustering algorithm in 3D images.

SETTING

University-based laboratory, Tehran, Iran.

METHODS

T2 structural volumes acquired from the spinal cord of 20 uninjured volunteers on a 3T MR scanner. We proposed an automatic method for spinal cord segmentation based on the K-means clustering algorithm in 3D images and compare our results with two available segmentation methods (PropSeg, DeepSeg) implemented in the Spinal Cord Toolbox. Dice and Hausdorff were used to compare the results of our method (K-Seg) with the manual segmentation, PropSeg, and DeepSeg.

RESULTS

The accuracy of our automatic segmentation method for T2-weighted images was significantly better or similar to the SCT methods, in terms of 3D DC (p < 0.001). The 3D DCs were respectively (0.81 ± 0.04) and Hausdorff Distance (12.3 ± 2.48) by the K-Seg method in contrary to other SCT methods for T2-weighted images.

CONCLUSIONS

The output with similar protocols showed that K-Seg results match the manual segmentation better than the other methods especially on the thoracolumbar levels in the spinal cord due to the low image contrast as a result of poor SNR in these areas.

Evaluation of contrast agent dose and diffusion coefficient measurement on vessel size index estimation

OBJECTIVES

The goal of this study is to examine the effect of contrast agent (CA) dose and diffusion coefficient on the estimation of vessel size index (VSI).

MATERIALS AND METHODS

Three groups of four participants were enrolled in this study and two different experiments were performed. Different dose of CA, namely 0.1 mmol/kg and 0.05 mmol/kg were assessed in two groups of normal subjects. Diffusion coefficient effect was assessed in the third group with high-grade glioma. Imaging included gradient echo and spin-echo DSC and DTI on a 3-T MR Scanner.

RESULTS

VSI estimation using half of standard dose of CA showed higher values compared to the application of standard, with a ratio of 2 for the WM and 1.5 for the GM. VSI estimates for tumor tissues (22 µm) were considerably higher compared to contra-lateral Normal-Appearing WM (NAWM, 4 µm, P < 0.01) and Normal-Appearing GM (NAGM, 8 µm, P < 0.04).

DISCUSSION

Application of standard dose for CA injection and also taking into account the effect of diffusion coefficient can lead to a better correlation of VSI with previous theoretically predicted values and improvement of individual diagnostics in tumor evaluations.

Comparison of Qualitative (Time Intensity Curve Analysis), Semi-Quantitative, and Quantitative Multi-Phase 3T DCEMRI Parameters as Predictors of Malignancy in Adnexal

Objective:

The present study aimed to compare the qualitative (time intensity curve analysis), the semi-quantitative and the quantitative multiphase 3T dynamic contrast-enhanced (DCE) MRI parameters as predictors of malignancy in adnexal masses. Materials and

Methods:

In this prospective study, women with an adnexal mass who were scheduled for surgical resection or were followed for more than one year period to confirm the benignity of their lesions, underwent multiphase 3T DCE-MRI. The qualitative (time intensity curve), semi-quantitative (SImax, SIrel, WIR) and quantitative (Ktrans, Kep, Vb) analyses were performed on DCE-MRI sequences and their predictive values were compared.

Results:

A total of 17 benign and 14 malignant lesions were included. According to the qualitative analysis, none of the lesions with Type I time intensity curves (TIC) were malignant and none of the masses with Type III TICs were benign. The accuracy of the quantitative parameters in detection of malignancy was found to be higher than that of semi-quantitative variables, particularly when calculated for a small ROI within the high signal area of the mass (sROI) rather than the largest ROI including the whole mass (lROI), and when inter-MRI variations were omitted using ratios. The Kep(tumor)/Kep(myometrium) ratio measured from sROI was the best parameter for differentiating a malignant lesion with a sensitivity of 100% and a specificity of 92.3%.

Conclusion:

We concluded that a Type I TIC confirms a benign lesion, and a type III TIC confirms the malignancy and further evaluation is not recommended for these lesions. So complementary quantitative analysis is only recommended for adnexal masses with type II TICs.

Longitudinal Effects of Bumetanide on Neuro-Cognitive Functioning in Drug-Resistant Epilepsy

Antiepileptic drugs (AEDs) have repeatedly shown inconsistent and almost contradictory effects on the neurocognitive system, from substantial impairments in processing speed to the noticeable improvement in working memory and executive functioning. Previous studies have provided a novel insight into the cognitive improvement by bumetanide as a potential antiepileptic drug. Through the current investigation, we evaluated the longitudinal effects of bumetanide, an NKCC1 co-transporter antagonist, on the brain microstructural organization as a probable underlying component for cognitive performance. Microstructure assessment was completed using SPM for the whole brain assay and Freesurfer/TRACULA for the automatic probabilistic tractography analysis. Primary cognitive operations including selective attention and processing speed, working memory capacity and spatial memory were evaluated in 12 patients with a confirmed diagnosis of refractory epilepsy. Participants treated with bumetanide (2 mg/ day) in two divided doses as an adjuvant therapy to their regular AEDs for 6 months, which followed by the re-assessment of their cognitive functions and microstructural organizations. Seizure frequency reduced in eight patients which accompanied by white matter reconstruction; fractional anisotropy (FA) increased in the cingulum-cingulate gyrus (CCG), anterior thalamic radiation (ATR), and temporal part of the superior longitudinal fasciculus (SLFt) in correlation with the clinical response. The voxel-based analysis in responder patients revealed increased FA in the left hippocampus, right cerebellum, and right medial temporal lobe, while mean diffusivity (MD) values reduced in the right occipital lobe and cerebellum. Microstructural changes in SLFt and ATR accompanied by a reduction in the error rate in the spatial memory test. These primary results have provided preliminary evidence for the effect of bumetanide on cognitive functioning through microstructural changes in patients with drug-resistant epilepsy.

Synthesis and Biological Evaluation of a Novel Glucosylated Derivative of Gadolinium Diethylenetriaminepentaacetic Acid for Tumor Magnetic Resonance Imaging

Cancer detection in early stage using a powerful and noninvasive tool is of high global interest. In this experiment, a small-molecular-weight glucose based derivative of Gd³⁺-1-(4-isothiocyanatobenzyl) diethylene tri amine penta acetic acid (Gd³⁺-p-SCN-Bn-DTPA-DG) as a novel potential MR imaging contrast agents was synthesized. Gd³⁺-p-SCN-Bn-DTPA-DG was synthesized with reacting of Glucosamine and 1-(4-isothiocyanatobenzyl) diethylene triamine penta acetic acid then loaded by gadolinium to make novel agent of functional MR imaging. The relaxivity, T ₁, T ₂ relaxation times, and cell toxicity of this contrast agent were studied. The results demonstrated that the sugar moieties linked to Gd³⁺-p-SCN-Bn-DTPA efficiently increase its cellular uptake in normal cells 25% and in cancereous cells upto 67%. The Gd³⁺-p-SCN-Bn-DTPA-DG significantly (p < 0.05) decreased MCF-7 tumor cell numbers without any significant toxicity on normal human kidney cells. Finally, it displayed an intense signal on T ₁ weighted with respect to the unlabeled cells. Based on the findings from the present research Gd³⁺-p-SCN-Bn-DTPA-DG be a potential breast molecular imaging. However, further investigations by anticancer studies are in the pipeline.

A machine learning approach for distinguishing uterine sarcoma from leiomyomas based on perfusion weighted MRI parameters

PURPOSE

To propose a computer-assisted method for distinguishing uterine sarcoma from leiomyomas based on perfusion weighted magnetic resonance imaging (PWI).

MATERIALS AND METHODS

Forty-two women confirmed to have a total of 60 masses (10 uterine sarcomas and 50 benign leiomyomas) were included. The reference diagnosis was based on postoperative histopathological examination. All women underwent the standard MRI protocol with 3-Tesla MR imager (Magnetom Trio, Siemens, Erlangen, Germany) for assessment of myometrial masses, followed by PWI. For each mass, two regions of interest (ROI) were outlined manually by an experienced radiologist; one (ROI_L) represented the entire tumor while the other (ROIs) was placed on the area of the lesion with the most marked contrast enhancement. Two additional ROI_s with diameters similar to ROI_s (3.0 to 3.1 mm) were placed on psoas muscle (ROI_P) and myometrium (ROI_M) in order to provide baselines for comparisons. The obtained ROIs of PWI images were then analyzed using the DCE Tool plug-in (version 2.0SP1) within ClearCanvas (Toronto, Ontario, Canada) framework. The DCE Tool provides seven parameters (K^trans, k_ep, V_b, IAUC, initial slope, peak, the mean squared error) for modelling contrast uptake within an ROI using the modified Tofts model. Parameters extracted from the ROIs were fed into a decision tree ensemble, which classified the corresponding lesions either as malignant or benign. The leave-one-out cross validation (LOOCV) was utilized to evaluate the performance of the classifier.

RESULTS

None of the parameters extracted from ROI_L or ROI_s differed significantly between uterine sarcoma and benign leiomyomas (all p > 0.05). The overall accuracy of 66.7% was obtained by feeding seven parameters extracted from ROI_L to the classifier. When 21 features extracted from ROI_L, ROI_M, and ROI_P were fed into the classifier an accuracy of 91.7%, sensitivity of 100%, and specificity of 90% were achieved in the optimal operating point of classifier.

CONCLUSION

Although none of the PWI parameters differed significantly between benign and malignant lesions, when the information provided by the extracted features was aggregated using a machine learning method, a promising discriminative power was obtained. This suggests that the proposed model for combining the PWI parameters is potentially useful for differentiating uterine sarcoma from leiomyomas.

Differentiation of Edematous, Tumoral and Normal Areas of Brain Using Diffusion Tensor and Neurite Orientation Dispersion and Density Imaging

BACKGROUND

Presurigical planning for glioma tumor resection and radiotherapy treatment require proper delineation of tumoral and peritumoral areas of brain. Diffusion tensor imaging (DTI) is the most common mathematical model applied for diffusion weighted MRI data. Neurite orientation dispersion and density imaging (NODDI) is another mathematical model for DWI data modeling.

OBJECTIVE

We studied whether extracted parameters of DTI, and NODDI models can be used to differentiate between edematous, tumoral, and normal areas in brain white matter (WM).

MATERIAL AND METHODS

12 patients with peritumoral edema underwent 3T multi-shell diffusion imaging with b-values of 1000 and 2000 smm-2 in 30 and 64 gradient directions, respectively. We fitted DTI and NODDI to data in manually drawn regions of interest and used their derived parameters to characterize edematous, tumoral and normal brain areas.

RESULTS

We found that DTI parameters fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) all significantly differentiated edematous from contralateral normal brain WM (p<0.005). However, only FA was found to distinguish between edematous WM fibers and tumor invaded fibers (p = 0.001). Among NODDI parameters, the intracellular volume fraction (ficvf) had the best distinguishing power with (p = 0.001) compared with the isotropic volume fraction (fiso), the orientation dispersion index (odi), and the concentration parameter of Watson distribution (κ), while comparing fibers inside normal, tumoral, and edematous areas.

CONCLUSION

The combination of two diffusion based methods, i.e. DTI and NODDI parameters can distinguish and characterize WM fibers involved in edematus, tumoral, and normal brain areas with reasonable confidence. Further studies will be required to improve the detectability of WM fibers inside the solid tumor if they hypothetically exist in tumoral parenchyma.

Detection of structural abnormalities of cortical and subcortical gray matter in patients with MRI-negative refractory epilepsy using neurite orientation dispersion and density imaging

PURPOSE

NODDI (Neurite Orientation Dispersion and Density Imaging) and DTI (Diffusion tensor imaging) may be useful in identifying abnormal regions in patients with MRI-negative refractory epilepsy. The aim of this study was to determine whether NODDI and DTI maps including neurite density (ND), orientation dispersion index (ODI), mean diffusivity (MD) and fractional anisotropy (FA) can detect structural abnormalities in cortical and subcortical gray matter (GM) in these patients. The correlation between these parameters and clinical characteristics of the disease was also investigated.

METHODS

NODDI and DTI maps of 17 patients were obtained and checked visually. Region of interest (ROI) was drawn on suspected areas and contralateral regions in cortex. Contrast-to-noise ratio (CNR) was determined for each region. Furthermore volumetric data and mean values of ND, ODI, FA and MD of subcortical GM structures were calculated in both of the patients and controls. Finally, the correlations of these parameters in the subcortical with age of onset and duration of epilepsy were investigated.

RESULTS

Cortical abnormalities on ODI images were observed in eight patients qualitatively. CNR of ODI was significantly greater than FA and MD. The subcortical changes including decrease of FA and ND and increase of ODI in left nucleus accumbens and increase of the volume in right amygdala were detected in the patients.

CONCLUSIONS

The results revealed that NODDI can improve detection of microstructural changes in cortical and subcortical GM in patients with MRI negative epilepsy.

Transcranial DC stimulation modifies functional connectivity of large-scale brain networks in abstinent methamphetamine users

Background

Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation tool suited to alter cortical excitability and activity via the application of weak direct electrical currents. An increasing number of studies in the addiction literature suggests that tDCS modulates subjective self-reported craving through stimulation of dorsolateral prefrontal cortex (DLPFC). The major goal of this study was to explore effects of bilateral DLPFC stimulation on resting state networks (RSNs) in association with drug craving modulation. We targeted three large-scale RSNs; the default mode network (DMN), the executive control network (ECN), and the salience network (SN).

Methods

Fifteen males were recruited after signing written informed consent. We conducted a double-blinded sham-controlled crossover study. Twenty-minute "real" and "sham" tDCS (2 mA) were applied over the DLPFC on two separate days in random order. Each subject received both stimulation conditions with a 1-week washout period. The anode and cathode electrodes were located over the right and left DLPFC, respectively. Resting state fMRI was acquired before and after real and sham stimulation. Subjective craving was assessed before and after each fMRI scan. The RSNs were identified using seed-based analysis and were compared using a generalized linear model.

Results

Subjective craving decreased significantly after real tDCS compared to sham stimulation (p = .03). Moreover, the analysis shows significant modulation of DMN, ECN, and SN after real tDCS compared to sham stimulation. Additionally, alteration of subjective craving score was correlated with modified activation of the three networks.

Discussion

Given the observed alteration of the targeted functional brain networks in methamphetamine users, new potentials are highlighted for tDCS as a network intervention strategy and rsfMRI as a suitable monitoring method for these interventions.

Assessment of the Agreement between Cerebral Hemodynamic Indices Quantified Using Dynamic Susceptibility Contrast and Dynamic Contrast-enhanced Perfusion Magnetic Resonance Imagings

Background:

Brain tumor is one of the most common tumors. A successful treatment might be achieved with an early identification. Pathological investigation as the gold standard method for tumor identification has some limitations. Noninvasive assessment of tumor specifications may be possible using perfusion-weighted magnetic resonance imaging (MRI). Cerebral blood volume (CBV) and cerebral blood flow (CBF) could be calculated based on dynamic contrast-enhanced MRI (DCE-MRI) in addition to dynamic susceptibility contrast MRI (DSC-MRI) modality. Each category of the cerebral hemodynamic and permeability indices revealed the specific tumor characteristics and their collection could help for better identification of the tumor. Some mathematical methods were developed to determine both cerebral hemodynamic and permeability indices based on a single-dose DCE perfusion MRI. There are only a few studies available on the comparison of DSC- and DCE-derived cerebral hemodynamic indices such as CBF and CBV.

Aim:

The objective of the study was to validate first-pass perfusion parameters derived from T1-based DCE method in comparison to the routine T2*-based DSC protocol.

Materials and Methods:

Twenty-nine patients with brain tumor underwent DCE- and DSC-MRIs to evaluate the agreement between DSC- and DCE-derived cerebral hemodynamic parameters. Agreement between DSC- and DCE-derived cerebral hemodynamic indices was determined using the statistical method described by Bland and Altman. The reliability between DSC- and DCE-derived cerebral hemodynamic indices was measured using the intraclass correlation analysis.

Results:

The achieved magnitudes for DCE-derived CBV (gray matter [GM]: 5.01 ± 1.40 mL/100 g vs. white matter [WM]: 1.84 ± 0.74 mL/100 g) and DCE-derived CBF (GM: 60.53 ± 12.70 mL/100 g/min vs. WM: 32.00 ± 6.00 mL/100 g/min) were in good agreement with other studies. The intraclass correlation coefficients showed that the cerebral hemodynamic indices could accurately be estimated based on the DCE-MRI using a single-compartment model (>0.87), and DCE-derived cerebral hemodynamic indices are significantly similar to the magnitudes achieved based on the DSC-MRI (P < 0.001). Furthermore, an acceptable agreement was observed between DSC- and DCE-derived cerebral hemodynamic indices.

Conclusion:

Based on the measurement of the cerebral hemodynamic and blood–brain barrier permeability using DCE-MRI, a more comprehensive collection of the physiological parameters cloud be achieved for tumor evaluations.

Not single brain areas but a network is involved in language: Applications in presurgical planning

OBJECTIVES

Language is an important human function, and is a determinant of the quality of life. In conditions such as brain lesions, disruption of the language function may occur, and lesion resection is a solution for that. Presurgical planning to determine the language-related brain areas would enhance the chances of language preservation after the operation; however, availability of a normative language template is essential.

PATIENTS AND METHODS

In this study, using data from 60 young individuals who were meticulously checked for mental and physical health, and using fMRI and robust imaging and data analysis methods, functional brain maps for the language production, perception and semantic were produced.

RESULTS

The obtained templates showed that the language function should be considered as the product of the collaboration of a network of brain regions, instead of considering only few brain areas to be involved in that.

CONCLUSION

This study has important clinical applications, and extends our knowledge on the neuroanatomy of the language function.

Analysis of Resting-State fMRI Topological Graph Theory Properties in Methamphetamine Drug Users Applying Box-Counting Fractal Dimension

Introduction:

Graph theoretical analysis of functional Magnetic Resonance Imaging (fMRI) data has provided new measures of mapping human brain in vivo. Of all methods to measure the functional connectivity between regions, Linear Correlation (LC) calculation of activity time series of the brain regions as a linear measure is considered the most ubiquitous one. The strength of the dependence obligatory for graph construction and analysis is consistently underestimated by LC, because not all the bivariate distributions, but only the marginals are Gaussian. In a number of studies, Mutual Information (MI) has been employed, as a similarity measure between each two time series of the brain regions, a pure nonlinear measure. Owing to the complex fractal organization of the brain indicating self-similarity, more information on the brain can be revealed by fMRI Fractal Dimension (FD) analysis.

Methods:

In the present paper, Box-Counting Fractal Dimension (BCFD) is introduced for graph theoretical analysis of fMRI data in 17 methamphetamine drug users and 18 normal controls. Then, BCFD performance was evaluated compared to those of LC and MI methods. Moreover, the global topological graph properties of the brain networks inclusive of global efficiency, clustering coefficient and characteristic path length in addict subjects were investigated too.

Results:

Compared to normal subjects by using statistical tests (P<0.05), topological graph properties were postulated to be disrupted significantly during the resting-state fMRI.

Conclusion:

Based on the results, analyzing the graph topological properties (representing the brain networks) based on BCFD is a more reliable method than LC and MI.

Changes in Effective Connectivity Network Patterns in Drug Abusers, Treated With Different Methods

Introduction:

Various treatment methods for drug abusers will result in different success rates. This is partly due to different neural assumptions and partly due to various rate of relapse in abusers because of different circumstances. Investigating the brain activation networks of treated subjects can reveal the hidden mechanisms of the therapeutic methods.

Methods:

We studied three groups of subjects: heroin abusers treated with abstinent based therapy (ABT) method, heroin abusers treated with Methadone Maintenance Therapy (MMT) method, and a control group. They were all scanned with functional magnetic resonance imaging (fMRI), using a 6-block task, where each block consisted of the rest-craving-rest-neutral sequence. Using the dynamic causal modeling (DCM) algorithm, brain effective connectivity network (caused by the drug craving stimulation) was quantified for all groups. In this regard, 4 brain areas were selected for this analysis based on previous findings: ventromedial prefrontal cortex (VMPFC), dorsolateral prefrontal cortex (DLPFC), amygdala, and ventral striatum.

Results:

Our results indicated that the control subjects did not show significant brain activations after craving stimulations, but the two other groups showed significant brain activations in all 4 regions. In addition, VMPFC showed higher activations in the ABT group compared to the MMT group. The effective connectivity network suggested that the control subjects did not have any direct input from drug-related cue indices, while the other two groups showed reactions to these cues. Also, VMPFC displayed an important role in ABT group. In encountering the craving pictures, MMT subjects manifest a very simple mechanism compared to other groups.

Conclusion:

This study revealed an activation network similar to the emotional and inhibitory control networks observed in drug abusers in previous works. The results of DCM analysis also support the regulatory role of frontal regions on bottom regions. Furthermore, this study demonstrates the different effective connectivity patterns after drug abuse treatment and in this way helps the experts in the field.

Evaluation of the factors influencing brain language laterality in presurgical planning

Brain lesions cause functional deficits, and one treatment for this condition is lesion resection. In most cases, presurgical planning (PSP) and the information from laterality indices are necessary for maximum preservation of the critical functions after surgery. Language laterality index (LI) is reliably estimated using functional magnetic resonance imaging (fMRI); however, this measure is under the influence of some external factors. In this study, we investigated the influence of a number of factors on language LI, using data from 120 patients (mean age=35.65 (±13.4) years) who underwent fMRI for PSP. Using two proposed language tasks from our previous works, brain left hemisphere was showed to be dominant for the language function, although a higher LI was obtained using the "Word Generation" task, compared to the "Reverse Word Reading". In addition, decline of LIs with age, and lower LI when the lesion invaded brain language area were observed. Meanwhile, gender, lesion side (affected hemisphere), LI calculation strategy, and fMRI analysis Z-values did not statistically show any influences on the LIs. Although fMRI is widely used to estimate language LI, it is shown here that in order to present a reliable language LI and to correctly select the dominant hemisphere of the brain, the influence of external factors should be carefully considered.

Effect of coating thickness of iron oxide nanoparticles on their relaxivity in the MRI

OBJECTIVES

Iron oxide nanoparticles have found prevalent applications in various fields including drug delivery, cell separation and as contrast agents. Super paramagnetic iron oxide (SPIO) nanoparticles allow researchers and clinicians to enhance the tissue contrast of an area of interest by increasing the relaxation rate of water. In this study, we evaluate the dependency of hydrodynamic size of iron oxide nanoparticles coated with Polyethylene glycol (PEG) on their relativities with 3 Tesla clinical MRI.

MATERIALS AND METHODS

We used three groups of nanoparticles with nominal sizes 20, 50 and 100 nm with a core size of 8.86 nm, 8.69 nm and 10.4 nm that they were covered with PEG 300 and 600 Da. A clinical magnetic resonance scanner determines the T1 and T2 relaxation times for various concentrations of PEG-coated nanoparticles.

RESULTS

The size measurement by photon correlation spectroscopy showed the hydrodynamic sizes of MNPs with nominal 20, 50 and 100 nm with 70, 82 and 116 nm for particles with PEG 600 coating and 74, 93 and 100 nm for particles with PEG 300 coating, respectively. We foud that the relaxivity decreased with increasing overall particle size (via coating thickness). Magnetic resonance imaging showed that by increasing the size of the nanoparticles, r2/r1 increases linearly.

CONCLUSION

According to the data obtained from this study it can be concluded that increments in coating thickness have more influence on relaxivities compared to the changes in core size of magnetic nanoparticles.

An integrated assessment of morphology, size, and complement activation of the PEGylated liposomal doxorubicin products Doxil®, Caelyx®, DOXOrubicin, and SinaDoxosome

In order to improve patient's benefit and safety, comprehensive regulatory guidelines on specificities of Non-Biological Complex Drugs (NBCDs), such as doxorubicin-encapsulated liposomes, and their follow-on versions are needed. Here, we compare Doxil® and its European analog Caelyx® with the two follow-on products DOXOrubicin (approved by the US Food and Drug Administration) and SinaDoxosome (produced in Iran) by cryogenic transmission electron microscopy, dynamic light scattering and Nanoparticle Tracking Analysis, and assess their potential in activating the complement system in human sera. We found subtle physicochemical differences between the tested liposomal products and even between the tested batches of Doxil® and Caelyx®. Notably, these included differences in vesicular population aspect ratios and particle number. Among the tested products, only SinaDoxosome, in addition to the presence of unilamellar vesicles with entrapped doxorubicin crystals, contained empty circular disks. Differences were also found in complement responses, which may be related to some morphological differences. This study has demonstrated an integrated biophysical and immunological toolbox for improved analysis and detection of physical differences among vesicular populations that may modulate their clinical performance. Combined, these approaches may help better product selection for infusion to the patients as well as for improved design and characterization of future vesicular NBCDs with enhanced clinical performance and safety.

Exploring Neural Correlates of Different Dimensions in Drug Craving Self-Reports among Heroin Dependents

INTRODUCTION

Drug craving could be described as a motivational state which drives drug dependents towards drug seeking and use. Different types of self-reports such as craving feeling, desire and intention, wanting and need, imagery of use, and negative affect have been attributed to this motivational state. By using subjective self-reports for different correlates of drug craving along with functional neuroimaging with cue exposure paradigm, we investigated the brain regions that could correspond to different dimensions of subjective reports for heroin craving.

METHODS

A total of 25 crystalline-heroin smokers underwent functional magnetic resonance imaging (fMRI), while viewing heroin-related and neutral cues presented in a block-design task. During trial intervals, subjects verbally reported their subjective feeling of cue induced craving (CIC). After fMRI procedure, participants reported the intensity of their "need for drug use" and "drug use imagination" on a 0-100 visual analog scale (VAS). Afterwards, they completed positive and negative affect scale (PANAS) and desire for drug questionnaire (DDQ) with 3 components of "desire and intention to drug use," "negative reinforcement," and "loss of control."

RESULTS

The study showed significant correlation between "subjective feeling of craving" and activation of the left and right anterior cingulate cortex, as well as right medial frontal gyrus. Furthermore, the "desire and intention to drug use" was correlated with activation of the left precentral gyrus, left superior frontal gyrus, and left middle frontal gyrus. Subjects also exhibited significant correlation between the "need for drug use" and activation of the right inferior temporal gyrus, right middle temporal gyrus, and right parahippocampal gyrus. Correlation between subjective report of "heroin use imagination" and activation of the cerebellar vermis was also observed. Another significant correlation was between the "negative affect" and activation of the left precuneus, right putamen, and right middle temporal gyrus.

DISCUSSION

This preliminary study proposes different neural correlates for various dimensions of subjective craving self-reports. It could reflect multidimensionality of cognitive functions corresponding with drug craving. These cognitive functions could represent their motivational and affective outcomes in a single item "subjective craving feeling" or in self-reports with multiple dissociable items, such as intention, need, imagination, or negative feeling. The new psychological models of drug craving for covering various dimensions of subjective craving self-reports based on their neurocognitive correspondence could potentially modify craving assessments in addiction medicine.

Preparation and Characterization of Double Shell Fe3O4 Cluster@Nonporous SiO2@Mesoporous SiO2 Nanocomposite Spheres and Investigation of their In Vitro Biocompatibility

BACKGROUND

Multifunctional core-shell magnetic nanocomposite particles with tunable characteristics have been paid much attention for biomedical applications in recent years. A rational design and suitable preparation method must be employed to be able to exploit attractive properties of magnetic nanocomposite particles.

OBJECTIVES

Herein, we report on a simple approach for the synthesis of magnetic mesoporous silica nanocomposite particles (MMSPs), consisted of a Fe₃O₄ cluster core, a nonporous silica shell and a second shell of the mesoporous silica of suitable sizes for biomedical applications and evaluate their cytotoxicity effects on human cancer prostate cell lines.

MATERIALS AND METHODS

Clusters of magnetite (Fe₃O₄) nanoparticles were coated by a layer of nonporous silica using Stöber method. The coating step was completed by an outer layer of mesoporous silica via template-removing method. Structural properties of MMSPs were investigated by FTIR, HR-S(T)EM, BET, XRD techniques and magnetic properties of MMSPs by VSM instrument. MTT and LDH assays were employed to study the cytotoxicity of MMSPs.

RESULTS

Obtained results revealed that decreasing the precursor concentration and the reaction time at the nonporous silica shell formation step decreases the thickness of the nonporous silica shell and consequently leads to the formation of smaller MMSPs. The as-prepared MMSPs have a desirable average size of 180±10 nm, an average pore size of 3.01 nm, a high surface area of 390.4 m².g^-1 and a large pore volume of 0.294 cm³.g^-1. In addition, the MMSPs exhibited a superparamagnetic behavior and a high magnetization saturation value of 21±0.5 emu/g. Furthermore, the viability tests of DU-145 cell lines exposed to various concentrations of these particles demonstrated negligible cytotoxicity effects of the as-prepared particles.

CONCLUSIONS

These results demonstrate interesting properties of MMSPs prepared in this study for biomedical applications.

Methodological considerations in conducting an olfactory fMRI study

The sense of smell is a complex chemosensory processing in human and animals that allows them to connect with the environment as one of their chief sensory systems. In the field of functional brain imaging, many studies have focused on locating brain regions that are involved during olfactory processing. Despite wealth of literature about brain network in different olfactory tasks, there is a paucity of data regarding task design. Moreover, considering importance of olfactory tasks for patients with variety of neurological diseases, special contemplations should be addressed for patients. In this article, we review current olfaction tasks for behavioral studies and functional neuroimaging assessments, as well as technical principles regarding utilization of these tasks in functional magnetic resonance imaging studies.

Monoclonal antibody conjugated magnetic nanoparticles could target MUC-1-positive cells in vitro but not in vivo

MUC1 antigen is recognized as a high-molecular-weight glycoprotein that is unexpectedly over-expressed in human breast and other carcinomas. In contrast, C595 a monoclonal antibody (mAb) against the protein core of the human urinary epithelial machine, is commonly expressed in breast carcinomas. The aim of this study was to conjugate ultra-small super paramagnetic iron oxide nanoparticles (USPIO) with C595 mAb, in order to detect in vivo MUC1 expression. A dual contrast agent (the C595 antibody-conjugated USPIO labeled with 99mTc) was prepared for targeted imaging and therapy of anti-MUC1-expressing cancers. The C595 antibody-conjugated USPIO had good stability and reactivity in the presence of blood plasma at 37 °C. No significant differences were observed in immunoreactivity results between conjugated and nonconjugated nanoparticles. The T1 and T2 measurements show >79 and 29% increments (for 0.02 mg/ml iron concentrations) in T1 and T2 values for USPIO-C595 in comparison with USPIO, respectively. The nanoprobes showed the interesting targeting capability of finding the MUC1-positive cell line in vitro. However, we found disappointing in vivo results (i.e. very low accumulation of nanoprobes in the targeted site while >80% of the injected dose per gram was taken up by the liver and spleen), not only due to the coverage of targeting site by protein corona but also because of absorption of opsonin-based proteins at the surface of nanoprobes.

High frequency TMS for the management of Borderline Personality Disorder: a case report

OBJECTIVE

To assess the effect of repetitive trans-cranial magnetic stimulation (rTMS) therapy in the management of Borderline Personality Disorder (BPD).

METHOD

The subject was a 22 years old girl. She was first diagnosed with BPD after one of her suicidal attempts about two years ago. She received 10 sessions of high-frequency TMS over her left dorsolateral prefrontal cortex. Assessment was done before treatment, exactly after the last session, one and three months after treatment. Functional Scanning was performed before and after the TMS sessions and one month after the last session.

RESULTS

Results of block design analysis revealed increased activity in amygdala, Superior Temporal Gyrus, Superior Frontal Gyrus, Middle Frontal Gyrus and parahippocampus in negative-neutral and negative-rest contrasts. In contrast to the mentioned areas that exhibited decrease in activity after treatment, we found that middle temporal gyrus and post central gyrus were activated by the emotional stimuli. The changes in brain activity were associated with decrease in BPD severity (measured by BPD severity index) and depression and impulsivity level.

CONCLUSION

Regardless of the limitations of this study, our findings suggest a positive role for rTMS in the management of BPD.

Improving cellular uptake and in vivo tumor suppression efficacy of liposomal oligonucleotides by urea as a chemical penetration enhancer

BACKGROUND

Liposomes are among the most widely used carriers for the delivery of antisense oligonucleotides (AsODNs) to intracellular targets. Although different strategies have been employed, the question of how to improve liposomal uptake and enhance the release of AsODN into cytoplasm still remains to be answered with respect to the use of a safe, easy and economic method. In the present study, the possibility of enhancing such processes at cellular and animal levels using urea as a penetration enhancer was investigated.

METHODS

To perform this investigation, a cationic liposome containing an AsODN against protein kinase (PKC)-α was prepared, and the effect of urea on its cellular internalization and the related sequence-specific inhibition of gene expression in human lung adenocarcinoma A549 cells were investigated by flow cytometry and the reverse transcriptase-polymerase chain reaction, respectively. In in vivo studies, a xenograft lung tumor was established in nude mice by A549 cells and the enhancement effect of urea toward the effects of liposomal AsODN on tumor growth was investigated.

RESULTS

Cellular studies revealed that urea treatment increases liposomal uptake and the release of AsODN into the cytoplasm by approximately 40%. Sequence-specific inhibition of target gene PKC-α expression was also increased by approximately two-fold by urea at 200-300 nM AsODN. In animal studies, urea significantly decreased the tumor volume (approximately 40%) and increased its doubling time from approximately 13 days to 17 days.

CONCLUSIONS

Urea, and possibly other membrane fluidizers, could be regarded as penetration enhancers for liposomal AsODN delivery and may improve the therapeutic effect of these gene-therapy vectors at both cellular and animal levels.

False positive control of activated voxels in single fMRI analysis using bootstrap resampling in comparison to spatial smoothing

Functional magnetic resonance imaging (fMRI) is an effective tool for the measurement of brain neuronal activities. To date, several statistical methods have been proposed for analyzing fMRI datasets to select true active voxels among all the voxels appear to be positively activated. Finding a reliable and valid activation map is very important and becomes more crucial in clinical and neurosurgical investigations of single fMRI data, especially when pre-surgical planning requires accurate lateralization index as well as a precise localization of activation map. Defining a proper threshold to determine true activated regions, using common statistical processes, is a challenging task. This is due to a number of variation sources such as noise, artifacts, and physiological fluctuations in time series of fMRI data which affect spatial distribution of noise in an expected uniform activated region. Spatial smoothing methods are frequently used as a preprocessing step to reduce the effect of noise and artifacts. The smoothing may lead to a shift and enlargement of activation regions, and in some extend, unification of distinct regions. In this article, we propose a bootstrap resampling technique for analyzing single fMRI dataset with the aim of finding more accurate and reliable activated regions. This method can remove false positive voxels and present high localization accuracy in activation map without any spatial smoothing and statistical threshold setting.

Age-related frontal hyperactivation observed across different working memory tasks: an fMRI study

Purpose: To evaluate patterns of activation, convergence and divergence of three functional magnetic resonance imaging (fMRI) Working Memory (WM) tasks in two different age groups. We want to understand potential impact of task and subjects’ age on WM activations as well as most important areas with regard to WM functions.

Materials and methods: Thirty-five healthy volunteers completed visual, verbal, and novel auditory WM tasks. The subjects were selected from age extremes to depict possible impact of normal aging. The General Linear Model was used to report significant activations and the effect of age group. Contrasts revealed differences in activation between tasks, and Combined Task Analysis was performed to determine common regions of activation across tasks.

Results: Most of the observed differences between the tasks were seen in areas that were responsible for feature processing. Frontal regions were mainstay activation areas, regardless of the utilized stimulus. We found an age-related reduction in activity of visual (in visually-presented tasks) and auditory (in auditory task) cortices but an age-related increase in prefrontal cortex for all tasks.

Conclusion: Regardless of the type of the task stimuli, frontal regions are the most important activation areas in WM processing. These areas are also main targets of age-related changes with regard to activation patterns. Our results also indicate that prefrontal overactivity in working memory might be a compensatory effort to mask age-related decline in sensory processing.

Evaluating the effect of ultrasmall superparamagnetic iron oxide nanoparticles for a long-term magnetic cell labeling

In order to evaluate the long-term viability, the iron content stability, and the labeling efficiency of mammalian cells using magnetic cell labeling; dextran-coated ultrasmall superparamagnetic iron oxide (USPIOs) nanoparticles with plain surfaces having a hydrodynamic size of 25 nm were used for this study. Tests were carried out in four groups each containing 5 flasks of 5.5 × 10(6) AD-293 embryonic kidney cells. The cell lines were incubated for 24 h using four different iron concentrations with and without protamine sulfate (Pro), washed with phosphate-buffered saline (PBS) and centrifuged three times to remove the unbounded USPIOs. Cell viability was also verified using USPIOs. There were no significant differences in the cell viability between the control group of cells and those groups with iron uptake at the specified iron concentrations. The average iron uptake ratio compared to that of the control group was (114 ± 1). The magnetic resonance images (MRI) at post-labeling day 1 and day 21 showed (75 ± 4)% and (22 ± 5)% signal decrements compared to that of the control, respectively. The Perl's Prussian blue test showed that 98% of the cells were labeled, and the iron concentration within the media did not affect the cell iron uptake. Magnetic cellular labeling with the USPIO-Pro complex had no short or medium term (3 weeks) toxic effects on AD-293 embryonic kidney cells.

Impacts of normal aging on different working memory tasks: implications from an fMRI study

PURPOSE

To evaluate patterns of activation, convergence and divergence of three functional magnetic resonance imaging (fMRI) Working Memory (WM) tasks in two different age groups. We want to understand potential impact of task and subjects' age on WM activations as well as most important areas with regard to WM functions.

MATERIALS AND METHODS

Thirty-five healthy volunteers completed visual, verbal, and novel auditory WM tasks. The subjects were selected from age extremes to depict possible impact of normal aging. General Linear Model was used to report significant activations and the effect of group. One-to-one comparison of the tasks and Combined Task Analysis was also performed.

RESULTS

Most of the observed differences between the tasks were seen in areas that were responsible for feature processing. Frontal regions were mainstay activation areas, regardless of the utilized stimulus. We found an age-related reduction in activity of visual (in visually-presented tasks) and auditory (in auditory task) cortices but an age-related increase in prefrontal cortex for all tasks.

CONCLUSION

Regardless of the type of the task stimuli, frontal regions are the most important activation areas in WM processing. These areas are also main targets of age-related changes with regard to activation patterns. Our results also indicate that prefrontal overactivity in working memory might be a compensatory effort to mask age-related decline in sensory processing.

Preparation and in-vitro Evaluation of an Antisense-containing Cationic Liposome against Non-small Cell Lung Cancer: a Comparative Preparation Study

The current methods for treatment of cancers are inadequate and more specific methods such as gene therapy are in progress. Among different vehicles, cationic liposomes are frequently used for delivery of genetic material. This investigation aims to prepare and optimize DOTAP cationic liposomes containing an antisense oligonuclotide (AsODN) against protein kinase C alpha in non-small cells lung cancer (NSCLC). To perform this investigation, two different methods of ethanol injection and thin film hydration were used to prepare AsODN-loaded DOTAP liposomes. The formulated liposomes were then evaluated for their morphology, particle size, zeta potential and encapsulation efficiency, and the best formulation was chosen. In-vitro growth inhibitory effect of encapsulated ODN on A549 cells were evaluated by MTT and colonogenic assay. The physical and serum stability of liposomal ODN were also evaluated. Thin film hydration method resulted in large liposomes that required downsizing by extrusion with an encapsulation efficiency of 13%. Ethanol injection, in a single step gave liposomes with a small size of 115 nm and an encapsulation efficiency of around 90% which were physically stable for 6 months. The optimized liposome could protect oligonucleotides from degradation by nuclease. Cell studies showed a 20% sequence-specific inhibition of cell growth in MTT assay and revealed an LC50 of 103 nM in colonogenic studies. In conclusion, ethanol injection was able to provide suitable liposomes from the permanently charged DOTAP. Also the resulted liposomes were able to inhibit the growth of lung cancer cells.