Does the default-mode functional connectivity of the brain correlate with working-memory performances?

The "default-mode" network is an ensemble of cortical regions that are typically deactivated during demanding cognitive tasks in functional magnetic resonance imaging (fMRI) studies. Using functional connectivity analysis, this network can be studied as a "stand-alone" brain system whose functional role is supposed to consist in the dynamic control of intrinsic processing activities like attention focusing and task-unrelated thought generation and suppression. Independent component analysis (ICA) is the method of choice for generating a statistical image of the "default-mode" network (DMN) using a task- and seed-independent distributed model of fMRI functional connectivity without prior specification of node region extent and timing of neural activation. We used a standard graded working-memory task (n-back) to induce fMRI changes in the default-mode regions and ICA to evaluate to DMN functional connectivity in nineteen healthy volunteers. Based on the known spatial variability of the ICA-DMN maps with the task difficulty levels, we hypothesized the ICA-DMN may also correlate with the subject performances. We confirmed that the relative extent of the anterior and posterior midline spots within the DMN were oppositely (resp. positively in the anterior and negatively in the posterior cingulate cortex) correlated with the level of task difficulty and found out that the spatial distribution of DMN also correlates with the individual task performances. We conclude that the working-memory function is related to a spatial re-configuration of the DMN functional connectivity, and that the relative involvement of the cingulate regions within the DMN might function as a novel predictor of the working-memory efficiency.

Multiplexed AQUA-based assessment of SWOG 9313 shows prognostic value of continuous ER, PR and HER2 assessment

Abstract #704

Introduction: HER2 is expressed at high levels due to gene amplification in about 15% of breast cancer cases and it has been shown to be a poor prognostic marker. However, HER2 is also expressed in normal breast duct tissue, albeit a much lower levels. We hypothesized that continuous analysis of expression using AQUA will provide prognostic information beyond that attainable with conventional methods.
 Methods: A tissue microarray was made from 2123 cases of the 3122 patients accrued to SWOG 9313, in which sequential doxorubicin and cyclophosphamide (A-C) was compared to combination AC. A multiplexed assessment of HER2 and estrogen receptor (ER) was performed on the same slide using the immunofluoresence-based AQUA® method of automated quantitative analysis. Reproducibility and fidelity of multiplexing were determined for each marker by regression analysis.
 Results: As expected, both ER and PR were significantly predictive of disease-free survival (DFS) when both are tested as continuous variables, both adjusted for node status, tumor size, treatment and menopausal status (p-values 0.005 and <0.001, respectively). HER2, measured as a continuous variable showed a bi-phasic effect. It has been previously reported (Camp et al, Cancer Research 2003, 63;1445) that both the high and low expressers of HER2 have worse outcome (low levels are equivalent to that seen in normal breast ducts). Splitting the SWOG cohort by deciles shows that both the top and bottom decile have worse DFS than the middle 80% (log rank p=0.012). Also, modeling the hazard ratio as a function of concentration shows a U-shape relationship showing both high and low HER2 expression is associated with poorer DFS.
 Conclusions: The AQUA method provides a reproducible method of continuous measurement of ER, and HER2 on the same slide. In this cohort both ER and PR as continuous variable are highly prognostic, as expected, but multiplexing with HER2 did not affect outcome. Quantitative analysis demonstrated that both low and high levels of HER2 expression were associated with poor outcome. Studies are ongoing to determine the significance of this observation with respect to biological classifications of breast cancer and relationships with breast cancer therapies.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 704.

Brain atrophy evolution and lesion load accrual in multiple sclerosis: a 2-year follow-up study

Background

To investigate in a large cohort of patients with multiple sclerosis (MS), lesion load and atrophy evolution, and the relationship between clinical and magnetic resonance imaging (MRI) correlates of disease progression.

Methods

Two hundred and sixty-seven patients with MS were studied at baseline and two years later using the same MRI protocol. Abnormal white matter fraction, normal appearing white matter fraction, global white matter fraction, gray matter fraction and whole brain fraction, T2-hyperintense, and T1-hypointense lesions were measured at both time points.

Results

The majority of patients were clinically stable, whereas MRI-derived brain tissue fractions were significantly different after 2 years. The correlation between MRI data at baseline and their variation during the follow-up showed that lower basal gray matter atrophy was significantly related with higher progression of gray matter atrophy during follow-up. The correlation between MRI parameters and disease duration showed that gray matter atrophy rate decreased with increasing disease duration, whereas the rate of white matter atrophy had a constant pattern. Lower basal gray matter atrophy was associated with increased probability of developing gray matter atrophy at follow-up, whereas gray matter atrophy progression over 2 years and new T2 lesion load were risk factors for whole brain atrophy progression.

Conclusions

In MS, brain atrophy occurs even after a relatively short period of time and in patients with limited progression of disability. Short-term brain atrophy progression rates differ across tissue compartments, as gray matter atrophy results more pronounced than white matter atrophy and appears to be a early phenomenon in the MS-related disease progression.

A novel Angiogenin gene mutation in a sporadic patient with amyotrophic lateral sclerosis from southern Italy

Mutations in the Angiogenin gene (ANG) linked to 14q11.2 have been recently discovered to be associated with Amyotrophic Lateral Sclerosis (ALS) in Irish and Scottish populations. In our study we investigated the role of ANG gene in ALS patients from southern Italy. We found a novel mutation in the signal peptide of the ANG gene in a sporadic patient with ALS (SALS). The molecular analysis of the ANG gene also demonstrated an allelic association with the rs11701 single nucleotide polymorphism (SNP) in familial ALS (FALS) but not in SALS patients. Our finding supports the evidence that the ANG gene is involved in ALS.

Clinical and electrodiagnostic follow-up of an adolescent poisoned with thallium

We report a six-year clinical and electrodiagnostic follow-up of an adolescent patient with acute thallium poisoning from attempted suicide. During the acute stage the patient showed gastrointestinal disturbances, alopecia, and clinical and electrodiagnostic signs of severe polyneuropathy. Three years after poisoning, his neurological symptomatology was making progress, and electrophysiologic signs of peripheral neuropathy were mainly confined to lower limbs. Six years after intoxication, he was still complaining of weakness and sensory disturbances at the level of distal lower extremities; his neurologic and electrodiagnostic abnormalities affected mainly the feet. In this case report we underline the importance of early diagnosis and treatment to prevent neurological damage and the role of serial electromyographic and nerve conduction studies in thallium poisoning. These investigations allowed the authors to depict the electrophysiologic course of peripheral nervous system involvement over six years following poisoning.

A multiparametric brain and cord MR imaging study of a patient with Hirayama disease

In this study, we used a multiparametric MR imaging approach to assess a patient with Hirayama disease (HD). We found that cervical cord damage extends beyond cord T2-visible lesions. We also showed an altered pattern of cortical activations during movements of clinically unaffected limbs. Whereas this study suggests a more widespread cord involvement in HD than seen on routine MR imaging, its cause remains unclear (vascular damage versus a primary lower motor neuron disease).

Spectroscopic, diffusion and perfusion magnetic resonance imaging at 3.0 Tesla in the delineation of glioblastomas: preliminary results

Recent advances in magnetic resonance imaging (MRI) have allowed the evaluation of metabolic, diffusion and hemodynamic features of malignant gliomas. The aim of this study was to evaluate whether such information provided useful, complementary information to conventional MRI for improving the evaluation of glioblastoma extent. Ten patients with glioblastoma multiforme underwent conventional MRI, proton MR spectroscopic imaging (1H-MRSI), perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI). Metabolite signals, including normalized choline, N-acetylaspartate, creatine and lactate/lipids, were obtained by 1H-MRSI; apparent diffusion coefficient (ADC) by DWI; and relative cerebral blood volume (rCBV) by PWI. In edematous-appearing areas, 3 multiparametric patterns were identified: infiltrating tumor, with abnormal metabolite ratios, lower ADC and higher rCBV; pure edema, with normal metabolite ratios, higher ADC and lower rCBV; and tumor-infiltrated edema, with abnormal metabolite ratios and intermediate ADC and rCBV. In normal-appearing areas, 2 multiparametric patterns were identified: tumor-infiltrated tissue, with abnormal metabolite ratios and higher rCBV; and normal tissue, with normal MR parameters. The combination of 1H-MRSI, DWI and PWI features contributed to delineation of glioblastomas, offering information not available with conventional MRI. This approach may enhance the assessment of brain gliomas, providing useful information for guiding stereotactic biopsies, surgical resection and radiation treatment.

Treatment of multiple sclerosis with interferon beta in clinical practice: 2-year follow-up data from the South Italy Mobile MRI Project

This follow-up study assessed the 2-year clinical and magnetic resonance imaging (MRI) outcomes of patients with multiple sclerosis (MS) originally enrolled in an MRI study conducted at eight centres in south Italy (the South Italy Mobile MRI Project). Of the 597 MS patients recruited at baseline, 391 returned for the follow-up study. Of these, 363 provided 2-year clinical and MRI follow-up data, and 215 were still undergoing treatment with one of four interferon beta regimens: Avonex, 30 mcg intramuscularly once weekly; Betaferon, 250 mcg subcutaneously (sc) every other day; Rebif 22 mcg sc three times weekly (tiw; Rebif 22); or Rebif 44 mcg sc tiw (Rebif 44). Over the 2-year follow-up period, patients receiving the higher dose of Rebif were more likely to remain free from relapses [odds ratio (OR) = 2.23] and from developing both new T2 (OR = 0.15) and new T1 black hole lesions (OR = 0.22), when compared with patients in the Avonex group. Despite some limitations in the trial design, the results from this follow-up study provide helpful clinical and MRI data on the efficacy of interferon beta regimens in MS patients treated in the clinical setting.

Structure of msj-1 gene: a comparative analysis

Msj-1 gene encodes a DnaJ protein highly expressed in spermatids and spermatozoa of both rodents and amphibians. We isolated and characterized the msj-1 gene in mice. A bioinformatic approach was then used to predict the putative promoter region, chromosomal localization, and its presence in the human genome. The analysis of msj-1 genomic sequence revealed that msj-1 is an intronless gene. Interestingly, two regions (A and B, separated by 10,682 bp) on human chromosome 2 having respectively 78% and 77% nucleotide identity with the murine msj-1 coding region were identified. This suggests the existence of an msj-1-like gene also in humans.

Subcortical motor plasticity in patients with sporadic ALS: An fMRI study

OBJECTIVE

To address the potential contribution of subcortical brain regions in the functional reorganization of the motor system in patients with sporadic ALS (sALS) and to investigate whether functional changes in brain activity are different in sALS patients with predominant upper motor neuron (UMN) or lower motor neuron (LMN) dysfunction.

METHODS

We studied 16 patients with sALS and 13 healthy controls, using BOLD-fMRI, while they performed a simple visually paced motor task. Seven patients had definite clinical UMN signs while nine patients had prevalent clinical and electrophysiological LMN involvement. fMRI data were analyzed with Brain Voyager QX.

RESULTS

Task-related functional changes were identified in motor cortical regions in both patients and healthy controls. Direct group comparisons revealed relatively decreased BOLD fMRI responses in left sensorimotor cortex, lateral premotor area, supplementary motor area and right posterior parietal cortex (p < 0.05 corrected) and relatively increased responses in the left anterior putamen (p < 0.001 uncorrected) in sALS patients. Additional analyses between the two patients subgroups demonstrated significant BOLD fMRI response differences in the anterior cingulate cortex and right caudate nucleus (p < 0.001 uncorrected) with more robust activation of these areas in patients with greater UMN burden. Importantly, there were no significant differences in performance of the motor task between sALS patients and controls as well as between sALS patient subgroups.

CONCLUSIONS

Our data demonstrate a different BOLD fMRI pattern between our sALS patients and healthy controls even during simple motor behavior. Furthermore, patients with sALS and greater UMN involvement show a different reorganization of the motor system compared to sALS patients with greater LMN dysfunction.

Cognitive dysfunction in patients with relapsing-remitting multiple sclerosis

Cognitive dysfunction is considered one of the clinical markers of multiple sclerosis (MS). However, in the literature there are inconsistent reports on the prevalence of cognitive dysfunction, and separate data for the relapsing-remitting (RR) type of the disease are not always presented. In this study, we submitted 461 RRMS patients to a battery of neuropsychological tests to investigate their impairment in various cognitive domains. As a consequence of the exclusion criteria, the sample is not fully representative of the entire population of RRMS patients. In this selected sample, when only the eight scores of a core battery (Mental Deterioration Battery) were considered (with respective cutoffs), it emerged that 31% of the patients were affected by some degree of cognitive deficit. In particular, 15% had mild, 11.2% moderate and 4.8% had severe impairment. Information processing speed was the most frequently impaired area, followed by memory. When two other tests (SDMT and MCST) were added and cognitive domains were considered, it emerged that 39.3% of the patients were impaired in two or more domains. When four subgroups were obtained by means of cluster analysis and then compared, it emerged that information processing speed and memory deficits differentiated the still cognitively unimpaired from the mildly impaired MS patients. Significant associations were found between cognitive and clinical characteristics. However, due to the large sample size, clinically irrelevant relationships may also have emerged. Even with the limitations imposed by the sample selection and the possible underestimation of the prevalence and severity of cognitive dysfunction, these results seem to provide further evidence that information processing speed deficit may be an early and important marker of cognitive impairment in MS patients.

Brain atrophy and lesion load in a large population of patients with multiple sclerosis

OBJECTIVE

To measure white matter (WM) and gray matter (GM) atrophy and lesion load in a large population of patients with multiple sclerosis (MS) using a fully automated, operator-independent, multiparametric segmentation method.

METHODS

The study population consisted of 597 patients with MS and 104 control subjects. The MRI parameters were abnormal WM fraction (AWM-f), global WM-f (gWM-f), and GM fraction (GM-f).

RESULTS

Significant differences between patients with MS and control subjects included higher AWM-f and reduced gWM-f and GM-f. MRI data showed significant differences between patients with relapsing-remitting and secondary progressive forms of MS. Significant correlations between MRI parameters and between MRI and clinical data were found.

CONCLUSIONS

Patients with multiple sclerosis have significant atrophy of both white matter (WM) and gray matter (GM); secondary progressive patients have significantly more atrophy of both WM and GM than do relapsing-remitting patients and a significantly higher lesion load (abnormal WM fraction); lesion load is related to both WM and even more to GM atrophy; lesion load and WM and GM atrophy are significantly related to Expanded Disability Status Scale score and age at onset (suggesting that the younger the age at disease onset, the worse the lesion load and brain atrophy); and GM atrophy is the most significant MRI variable in determining the final disability.

Multiple sclerosis patients and immunomodulation therapies: the potential role of new MRI techniques to assess responders versus non-responders

Disease-modifying drugs (DMD) are effective in reducing relapses and magnetic resonance imaging (MRI) lesions in multiple sclerosis (MS). Nevertheless, individual treatment responses are variable, and accurate and reliable methods to identify DMD responsiveness have not been validated. Although extremely relevant in the study and management of MS, MRI data have not been systematically tested to answer this question yet. Here we present non-conventional MRI data, including magnetisation transfer imaging (MTI), diffusion-weighted imaging (DWI) and proton magnetic resonance spectroscopy ((1)HMRS). As these techniques are more sensitive to microstructural tissue changes and more specific for the heterogeneous pathological substrates of MS lesions, we anticipate their potential role for detecting relevant changes of tissue pathology during treatment of MS patients and, consequently, for a better definition of response status to therapy.

Smoking and longevity: an incompatible binomial?

In Western countries data from clinical and epidemiological studies have induced the public health offices to promote a great deal of advertising and informative campaigning for smoking reduction. Cigarette smoking has been clearly linked to the most common causes of death in the elderly and contributes to the higher death rate and disability rate associated with many chronic illnesses that are common in this age group. The combination of smoking along with other risk factors like hypertension and diabetes increase high frequency diseases, disability as well as adding to an increase in mortality rate. In order to verify if a healthy lifestyle really favors longevity and how much smoking is incompatible with extreme longevity we investigated the prevalence of smokers and the total smoking exposure of a sample of centenarians in relation with residual survival and health conditions. Our sample consists of 157 centenarians living in Rome, 39 males and 118 females (ratio m/f =1:3),mean age being 101.59 +/- 1.8 years (+/-SD), 83.8% of the centenarians have never smoked,13.5 % are former smokers, and 2.7% are active smokers. The average starting age of smoking is 21.2 years, while the average age of quitting is 65.7 years with an average of 44.7 +/- 17.1 smoking years. The average number of smoked cigarettes per day is quite low,less than 10 cigarettes, so that the total average number of smoked cigarettes is 158,045,well under 280,000 which is considered the cut-off point in many studies of when tumors are noticed. There seemed to be a significant difference (p < 0.001) in gender results in smokers: among male centenarians smokers reached 46%, while female smoker centenarians reached only 8.1%. Statistically significant chronic illnesses were noted among centenarian smokers over the age of 65 (p < 0.02). Moreover, Cox's regression has shown in centenarians a lower survival rate (p < 0.05) in smokers (20.7 +/- 11.2 months) than in non-smokers (27.0 +/- 19.0 months). In conclusion, our study evidences that smoking is for all but some exceptional subjects, incompatible with successful aging and compromises life expectancy even in extreme longevity.

Correlation between cognitive impairment and the Rey auditory-verbal learning test in a population with Alzheimer disease

Patients affected by Alzheimer disease (AD) need an accurate diagnosis, to the extent allowing us to find the best therapy or polytherapy, in order to take under control their cognitive impairment. In our Alzheimer Evaluation Units (from the Italian name abbreviated: UVA), the patients undergo a multidimensional evaluation, which can address us towards a proper diagnosis and of other weakening, or even dementia-related diseases. The patients are also subject to neuropsychometric and neuropsychological evaluations, allowing a more focused analysis on cognitive impairments. Among the tests, we use the Rey auditory-verbal learning test (RAVLT), evaluating the patient's verbal memory. A list of 15 words is read to each patient. N the first part of the test, the clinician repeats 5 times such a list. the patient is hen asked, at the end of every repetition, to tell all words he/she remembers. This part is useful to evaluate the immediate recall (IR) ability. The score, i.e., the total number of recalled words, ranges from 0 to 75. After 15 minutes, the delayed recall (DR) ability is evaluated: the patient is newly asked to repeat as many words as he can recall from the list. The score for this part ranges from 0 to 15 minutes. The score is corrected of rage and education, with a cut-off of 28.5 for IR and 4.7 for DR. We made a survey with the purpose of deciding if there was a correlation between cognitive impairment and verbal memory lack, whose deficiency appears earlier in AD. To this aim, we selected several patients with AD, diagnosed during the period between September 2002 and February 2003. We only considered those patients whose AD was not associated with other weakening diseases, and whose clinical dementia rating scale (CDR) score was between 0.5-2.0. A sample of 35 individuals (11 men and 24 women) could be obtained. A meaningful correlation was observed between CDR and IR (r = -0.725, p < 0.01), as well as between CDR and DR (r = -0.470; p < 0.05). Such a result confirms the importance of evaluating immediate and long-term memories, for the early diagnosis of AD, because it is the only symptom of clinically not yet diagnosed dementia, as proven also by other studies.

High-field proton MRS of human brain

Proton magnetic resonance spectroscopy (1H-MRS) of the brain reveals specific biochemical information about cerebral metabolites, which may support clinical diagnoses and enhance the understanding of neurological disorders. The advantages of performing 1H-MRS at higher field strengths include better signal to noise ratio (SNR) and increased spectral, spatial and temporal resolution, allowing the acquisition of high quality, easily quantifiable spectra in acceptable imaging times. In addition to improved measurement precision of N-acetylaspartate, choline, creatine and myo-inositol, high-field systems allow the high-resolution measurement of other metabolites, such as glutamate, glutamine, gamma-aminobutyric acid, scyllo-inositol, aspartate, taurine, N-acetylaspartylglutamate, glucose and branched amino acids, thus extending the range of metabolic information. However, these advantages may be hampered by intrinsic field-dependent technical difficulties, such as decreased T2 signal, chemical shift dispersion errors, J-modulation anomalies, increased magnetic susceptibility, eddy current artifacts, limitations in the design of homogeneous and sensitive radiofrequency (RF) coils, magnetic field instability and safety issues. Several studies demonstrated that these limitations could be overcome, suggesting that the appropriate optimization of high-field 1H-MRS would expand the application in the fields of clinical research and diagnostic routine.

GABA(B) receptor 1 polymorphism (G1465A) is associated with temporal lobe epilepsy

BACKGROUND

Dysfunction of gamma-aminobutyric acid (GABA) (B) receptors has been implicated in the pathogenesis of temporal lobe epilepsy (TLE).

OBJECTIVE

To evaluate the genetic contribution of cloned human GABA(B) receptors to TLE.

METHODS

The authors genotyped 141 patients (78 women and 63 men; mean age = 49.1 +/- 18.0 years) with nonlesional TLE and 372 age- and sex-matched normal individuals for the known polymorphism G1465A in the human GABA(B) receptor 1 [GABA(B[1])] gene.

RESULTS

There was a highly significant overrepresentation of the G1465A heterozygote in patients with TLE compared with controls. The A/G genotype was found in 17% of the 141 patients with TLE and in only 0.5% of the 372 controls (p < 0.0001). The authors also found that patients carrying the A allele had a significantly higher risk (p = 0.003, OR = 6.47, 95% CI = 2.02 to 20.76) of developing drug-resistant TLE. Furthermore, the age at onset of seizures tended to be lower in patients with A/G genotype, but the difference was not significant.

CONCLUSIONS

The results of this study indicate that the GABA(B[1]) polymorphism (G1465A) confers a highly increased susceptibility to TLE. Moreover, it seems to influence the severity of this common epileptic disorder.

Dilated Virchow-Robin spaces in myotonic dystrophy: frequency, extent and significance

To study the frequency, extent and significance of dilated Virchow-Robin spaces (VRSs) in dystrophia myotonica (DM), we evaluated the cranial magnetic resonance imaging (MRI) of 41 patients with the adult form of DM and 41 healthy controls. Dilated VRSs and white matter lesions (WMLs) were rated according to semiquantitative methods. Convexity VRSs were more frequent (68 vs. 34%; p < 0.01) and severer (median scores: 4 vs. 0; p < 0.01) in DM patients than in controls, while lenticulostriate VRSs did not show significant differences in frequency (83 vs. 70%; p > 0.05) and severity (median scores: 4 vs. 3; p > 0.05). WMLs were more frequent (66 vs. 22%; p < 0.01) and severer (median scores: 5 vs. 0; p < 0.01) in patients. Disease duration was negatively correlated with convexity VRSs and positively with lobar (centrum semiovale) WML scores. Dilated convexity VRSs might be one of the initial findings in cranial MRI of DM, preceding the appearance of lobar WMLs.

Proton MR spectroscopic imaging in multiple sclerosis

We studied 24 patients with multiple sclerosis (MS) by proton magnetic resonance spectroscopic imaging (1H-MRSI) to assess the neurochemical pathology of the white-matter lesions (WML) and normal-appearing white matter (NAWM). Our 1H-MRSI technique allowed simultaneous measurement of N-acetylaspartate (NAA), choline-containing compounds (Cho), and creatine plus phosphocreatine (Cr) signal intensities from four 15-mm slices divided into 0.84 ml single-volume elements. In WML we found significantly lower NAA/Cr and NAA/Cho ratios and a significantly higher Cho/Cr ratio than in NAWM or control white matter. In NAWM, NAA/Cr and Cho/Cr were significantly lower than in control white matter. 1H-MRSI was compatible with damage to myelin in WML, and with axonal damage and/or dysfunction in WML and NAWM. These findings extend data on involvement of NAWM in MS beyond the abnormalities visible on MRI.