Interactions between in vivo neuronal-glial markers, side of hippocampal sclerosis, and pharmacoresponse in temporal lobe epilepsy.

OBJECTIVE: To evaluate the interactions of metabolic neuronal-glial changes with the presence and hemispheric-side of hippocampal sclerosis (HS) and its potential role in predicting pharmacoresistance in temporal lobe epilepsy (TLE). METHODS: We included structural magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (1 H-MRS) metabolic data for 91 patients with unilateral TLE and 50 healthy controls. We measured the values of total N-acetyl aspartate/total creatine (tNAA/tCr), glutamate/tCr (Glu/tCr), and myo-inositol/tCr (mIns/tCr). To assess the influence of the pharmacoresponse and hemispheric-side of HS on metabolic data, the relationship between clinical and MRI data, and the predictive value of NAA/Cr, we used analysis of variance/covariance and built a logistic regression model. We used bootstrap simulations to evaluate reproducibility. RESULTS: Bilateral tNAA/tCr reduction was associated with pharmacoresistance and with left HS, a decrease of Glu/tCr ipsilateral to the seizure focus was associated with pharmacoresistance, and ipsilateral mIns/tCr increase was related to pharmacoresistance and the presence of left HS. The logistic regression model containing clinical and 1 H-MRS data discriminated pharmacoresistance (area under the curve [AUC] = 0.78). However, the reduction of tNAA/tCr was the main predictor, with the odds 2.48 greater for pharmacoresistance. SIGNIFICANCE: Our study revealed a spectrum of neuronal-glial changes in TLE, which was associated with pharmacoresistance, being more severe in left-sided HS and less severe in MRI-negative TLE. These noninvasive, in vivo biomarkers provide valuable additional information about the interhemispheric differences in metabolic dysfunction, seizure burden, and HS, and may help to predict pharmacoresistance.

Biological principles and clinical application of positron emission tomography-tracers in prostate cancer: a review.

Prostate carcinoma is the most common malignancy in men and the second cause of death by cancer in the western world. Currently, prostate carcinoma's diagnosis is achieved by transrectal ultrasound-guided biopsy (gold-standard), usually requested after an elevation of prostate specific antigen (PSA) levels or an abnormal digital rectal exam or transrectal ultrasound. Nevertheless, this diagnosis sequence sometimes presents with significant limitations. Therefore, there is a need of a diagnosis modality that improves the tumor detection rates and that offers information for its accurate staging, allowing the treatment's planning and administration. Molecular imaging by the means of positron emission tomography uses radiopharmaceuticals labeled with positron-emitting radioisotopes to detect metabolic changes that might be suggestive of cancer tissue. Recently, this technique has suffered a huge dynamic development, and researchers have been working on novel radiotracers agents to improve accuracy in targeting and detecting prostate tumors. On this review, it is highlighted that the most promising positron emission tomography-tracers that will, in a near future, not only improve diagnostic abilities for prostate carcinoma but also open new possibilities for theranostic approaches to treat this malignancy at a world level.

The superstatistical nature and interoccurrence time of atmospheric mercury concentration fluctuations.

The probability density function (PDF) of the time intervals between subsequent extreme events in atmospheric Hg0 concentration data series from different latitudes has been investigated. The Hg0 dynamic possesses a long-term memory autocorrelation function. Above a fixed threshold Q in the data, the PDFs of the interoccurrence time of the Hg0 data are well described by a Tsallis q-Exponential function. This PDF behavior has been explained in the framework of superstatistics, where the competition between multiple mesoscopic processes affects the macroscopic dynamics. An extensive parameter µ, encompassing all possible fluctuations related to mesoscopic phenomena, has been identified. It follows a χ 2-distribution, indicative of the superstatistical nature of the overall process. Shuffling the data series destroys the long-term memory, the distributions become independent of Q, and the PDFs collapse on to the same exponential distribution. The possible central role of atmospheric turbulence on extreme events in the Hg0 data is highlighted.

The associations between QCT-based vertebral bone measurements and prevalent vertebral fractures depend on the spinal locations of both bone measurement and fracture.

UNLABELLED: We examined how spinal location affects the relationships between quantitative computed tomography (QCT)-based bone measurements and prevalent vertebral fractures. Upper spine (T4-T10) fractures appear to be more strongly related to bone measures than lower spine (T11-L4) fractures, while lower spine measurements are at least as strongly related to fractures as upper spine measurements. INTRODUCTION: Vertebral fracture (VF), a common injury in older adults, is most prevalent in the mid-thoracic (T7-T8) and thoracolumbar (T12-L1) areas of the spine. However, measurements of bone mineral density (BMD) are typically made in the lumbar spine. It is not clear how the associations between bone measurements and VFs are affected by the spinal locations of both bone measurements and VF. METHODS: A community-based case-control study includes 40 cases with moderate or severe prevalent VF and 80 age- and sex-matched controls. Measures of vertebral BMD, strength (estimated by finite element analysis), and factor of risk (load:strength ratio) were determined based on QCT scans at the L3 and T10 vertebrae. Associations were determined between bone measures and prevalent VF occurring at any location, in the upper spine (T4-T10), or in the lower spine (T11-L4). RESULTS: Prevalent VF at any location was significantly associated with bone measures, with odds ratios (ORs) generally higher for measurements made at L3 (ORs = 1.9-3.9) than at T10 (ORs = 1.5-2.4). Upper spine fracture was associated with these measures at both T10 and L3 (ORs = 1.9-8.2), while lower spine fracture was less strongly associated (ORs = 1.0-2.4) and only reached significance for volumetric BMD measures at L3. CONCLUSIONS: Closer proximity between the locations of bone measures and prevalent VF does not strengthen associations between bone measures and fracture. Furthermore, VF etiology may vary by region, with VFs in the upper spine more strongly related to skeletal fragility.

Neocortical atrophy in Machado-Joseph disease: a longitudinal neuroimaging study.

BACKGROUND/PURPOSE: Previous imaging studies in the Machado-Joseph disease (MJD/SCA3) have mostly concentrated on the cerebellum and brainstem. Our goal was to perform a whole brain longitudinal evaluation. METHODS: We included 45 patients and 51 controls, who underwent two brain magnetic resonance imaging and magnetic resonance spectroscopy (mean interval of 12.5 ± 1.5 months). We used voxel-based morphometry (VBM) and the MarsBar analysis toolbox to extract grey matter density (GMD) values from regions of interest. We used a linear regression model and a general linear model to correlate GMD with clinical markers, and paired t-test for the longitudinal evaluation. RESULTS: We observed decreased GMD (P < .01) at frontal, parietal, temporal and occipital lobes, subcortical grey matter, cerebellum, and brainstem. White matter atrophy was restricted to the cerebellum. Age, CAG, and disease duration predicted GMD in different areas, but age and CAG were the most important predictors. The longitudinal analysis failed to demonstrate changes. Changes in regions other than the cerebellum appeared to contribute significantly to the final International Cooperative Ataxia Rating Scale score. CONCLUSION: We confirmed cortical involvement in MJD/SCA3. The most important factors in predicting GMD were age and CAG. The lack of progression of atrophy may indicate floor effect and/or short duration of follow-up.

Proton MRS may predict AED response in patients with TLE.

PURPOSE: To compare relative N-acetylaspartate (NAA) measurements in temporal lobe epilepsy (TLE) patients with good response to the first trial of antiepileptic drugs (AEDs) (an important prognostic factor) to TLE patients who failed the first AED monotherapy and required further AED trials with monotherapy or polytherapy. METHODS: We studied 25 consecutive TLE patients who responded to first AED (responders) and 21 who did not (failure-group), as well as 27 controls. Patients were seen regularly in our Epilepsy Service and underwent electroencephalography (EEG) investigation, high-resolution magnetic resonance imaging (MRI), and single-voxel proton MR spectroscopy. Voxels were tailored to the medial temporal region on each side and involved the anterior hippocampus. RESULTS: Analysis of variance (ANOVA) demonstrated significant variation of NAA/creatine (NAA/Cr) values in both hippocampi, ipsilateral and contralateral to the EEG focus (p < 0.001 and p = 0.021) across the groups. Pairwise post hoc comparisons showed reduced NAA/Cr in both hippocampi of failure-group compared to controls (p < 0.001) and compared to responders (p < 0.05), but not between the controls and responders. Individual analyses showed NAA/Cr ratios lower than 2 SDs (standard deviations) below the mean of controls in 9 of 21 patients (42.8%) in the failure-group (6 with unilateral and 3 with bilateral reduction) but in none of the responders. DISCUSSION: These results indicate that patients with TLE who respond well to the first AED have significantly less evidence of neuronal and axonal damage/dysfunction compared to those who are refractory to the first AED trial.