Language and Motor fMRI Activation in Polymicrogyric Cortex

PURPOSE

To analyze the patterns of brain activation in polymicrogyric cortex in epilepsy patients by blood oxygenation level-dependent (BOLD) functional MRI (fMRI), during language and motor activation tasks.

METHODS

Five patients with extratemporal epilepsy associated with polymicrogyria were scanned in a 1.5-T Siemens scanner with BOLD fMRI sequences, by following language and motor paradigms. Functional images were processed by using Brain Voyager software.

RESULTS

Activation of polymicrogyric cortex in the brain area that corresponds to the motor strip was present in all patients. Language studies revealed activation of polymicrogyric cortex over Broca's area in three cases.

CONCLUSIONS

Functionality was shown in polymicrogyric areas. Therefore if surgical resection is indicated, a careful functional planning is necessary because of functionality of the polymicrogyric cortex.

Evaluation of functional stability of quercetin as a raw material and in different topical formulations by its antilipoperoxidative activity

The present study evaluates the antioxidant activity of the flavonol quercetin, and its functional stability as a raw material and when added in formulations. The iron-chelating activity was determined using the bathophenanthroline assay, and the functional stability was evaluated with the antilipoperoxidative assay. Raw material presented concentration-dependent antilipoperoxidative and iron-chelating activities. The initial antilipoperoxidative activity of the raw material, cream and gel-cream were 63%, 78%, and 69%, respectively. There was no detectable loss of activity during 182 days (6 months) of storage at all tested temperatures (4 degrees C, room temperature [RT], 37 degrees C, and 45 degrees C) for the raw material. Considering the method variability of 10%, activity loss greater than 10% for nonionic cream was detected after 126 days at 4 degrees C (20.1%), decreasing thereafter to 22.2% after 182 days. At 45 degrees C, the loss of activity started after 182 days (13.2%). For the anionic gel-cream, activity loss started after 84 days (28.4%, 45 degrees C), decreasing after 182 days to 40.3% at 45 degrees C. At 37 degrees C, activity loss was detected after 182 days (12%). In conclusion, the results suggest that the activity of quercetin depends on iron chelation, and its possible usefulness as a topical antioxidant to prevent oxidative stress-induced skin damage depends on maintaining its antilipoperoxidative activity stored at RT, which avoids special storage conditions.

Autosomal dominant atretic cephalocele with phenotype variability: Report of a Brazilian family with six affected in four generations

Atretic cephalocele is a clinicopathological entity, which is different from the common form of cephalocele. Its etiopathogenesis has not been completely explained and there are only two previous reports of familial recurrence. We report a Brazilian family with autosomal dominant inheritance with variable expressivity.

Firstin vivo MRI assessment of a self-assembled metallostar compound endowed with a remarkable high field relaxivity

{Fe[Gd(2)bpy(DTTA)(2)(H(2)O)(4)](3)}(4-) is a self-assembled, metallostar-structured potential MRI contrast agent, with six efficiently relaxing Gd(3+) centres confined into a small molecular space. Its proton relaxivity is particularly remarkable at very high magnetic fields (r(1) = 15.8 mM(-1) s(-1) at 200 MHz, 37 degrees C, in H(2)O). Here we report the first in vivo MRI feasibility study, complemented with dynamic gamma scintigraphic imaging and biodistribution experiments using the (153)Sm-enriched compound. Comparative MRI studies have been performed at 4.7 T in mice with the metallostar and the small molecular weight contrast agent gadolinium(III)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate ([Gd(DOTA)(H(2)O)](-) = GdDOTA). The metallostar was well tolerated by the animals at the concentrations of 0.0500 (high dose) and 0.0125 (low dose) mmol Gd kg(-1) body weight; (BW). The signal enhancement in the inversion recovery fast low angle shot (IR FLASH) images after the high-dose metallostar injection was considerably higher than after GdDOTA injection (0.1 mmol Gd kg(-1) BW), despite the higher dose of the latter. The high-dose metallostar injection resulted in a greater drop in the spin-lattice relaxation time (T(1)), as calculated from the inversion recovery true fast imaging with steady-state precession (IR TrueFISP) data for various tissues, than the GdDOTA or the low dose metallostar injection. In summary, these studies have confirmed that the approximately four times higher relaxivity measured in vitro for the metallostar is retained under in vivo conditions. The pharmacokinetics of the metallostar was found to be similar to that of GdDOTA, involving fast renal clearance, a leakage to the extracellular space in the muscle tissue and no leakage to the brain. As expected on the basis of its moderate molecular weight, the metallostar does not function as a blood pool agent. The dynamic gamma scintigraphic studies performed in Wistar rats with the metallostar compound having (153)Sm enrichment also proved the renal elimination pathway. The biodistribution experiments are in full accordance with the MR and scintigraphic imaging. At 15 min post-injection the activity is primarily localized in the urine, while at 24 h post-injection almost all radioactivity is cleared from tissues and organs.

Targeting of lanthanide(III) chelates of DOTA-type glycoconjugates to the hepatic asyaloglycoprotein receptor: cell internalization and animal imaging studies

The characterization of a new class of hydrophilic liver-targeted agents for gamma-scintigraphy and MRI, consisting, respectively, of [(153)Sm](3+) or Gd(3+) complexes of DOTA monoamide or bisamide linked glycoconjugates (DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid), is reported. In vitro studies show high uptake of radiolabeled [(153)Sm]-DOTAGal(2) by the human hepatocyte carcinoma cell line Hep G2 containing the asialoglycoprotein receptor (ASGP-R), which is decreased to less than 50% by the presence of its high-affinity ligand asialofetuin (ASF). In vivo biodistribution, gamma-imaging and pharmacokinetic studies on Wistar rats using the [(153)Sm](3+)-labeled glycoconjugates show a high uptake in the receptor-rich organ liver of the radiolabeled compounds containing terminal galactosyl groups, but very little uptake for those compounds with terminal glycosyl groups. Blocking the receptor in vivo reduced liver uptake by 90%, strongly suggesting that the liver uptake of these compounds is mediated by their binding to the asyaloglycoprotein receptor (ASGP-R). This study also demonstrated that the valency increase improves the targeting capability of the glycoconjugates, which is also affected by their topology. However despite the specific liver uptake of the radiolabeled galactose-bearing multivalent compounds, the animal MRI assessment of the corresponding Gd(3+) chelates shows liver-to-kidney contrast effects which are not significantly better than those shown by GdDTPA. This probably results from the quick wash-out from the liver of these highly hydrophilic complexes, before they can be sufficiently concentrated within the hepatocytes via receptor-mediated endocytosis.

Vimang (Mangifera indica L. extract) induces permeability transition in isolated mitochondria, closely reproducing the effect of mangiferin, Vimang's main component

Mitochondrial permeability transition (MPT) is a Ca(2+)-dependent, cyclosporin A (CsA)-sensitive, non-selective inner membrane permeabilization process. It is often associated with apoptotic cell death, and is induced by a wide range of agents or conditions, usually involving reactive oxygen species (ROS). In this study, we demonstrated that Mangifera indica L. extract (Vimang), in the presence of 20 microM Ca(2+), induces MPT in isolated rat liver mitochondria, assessed as CsA-sensitive mitochondrial swelling, closely reproducing the same effect of mangiferin, the main component of the extract, as well as MPT-linked processes like oxidation of membrane protein thiols, mitochondrial membrane potential dissipation and Ca(2+) release from organelles. The flavonoid catechin, the second main component of Vimang, also induces MPT, although to a lesser extent; the minor, but still representative Vimang extract components, gallic and benzoic acids, show respectively, low and high MPT inducing abilities. Nevertheless, following exposure to H(2)O(2)/horseradish peroxidase, the visible spectra of these compounds does not present the same changes previously reported for mangiferin. It is concluded that Vimang-induced MPT closely reproduces mangiferin effects, and proposed that this xanthone is the main agent responsible for the extract's MPT inducing ability, by the action on mitochondrial membrane protein thiols of products arising as a consequence of the mangiferin's antioxidant activity. While this effect would oppose the beneficial effect of Vimang's antioxidant activity, it could nevertheless benefit cells exposed to over-production of ROS as occurring in cancer cells, in which triggering of MPT-mediated apoptosis may represent an important defense mechanism to their host.

Hypolipemic and antioxidant activities from Tamarindus indica L. pulp fruit extract in hypercholesterolemic hamsters

Dietary modifications may significantly reduce cardiovascular disease (CVD) risk factors, including cholesterol and atherosclerosis. The present study addressed the effects of the crude extract from the pulp fruit of Tamarindus indica L. on lipid serum levels and early atherosclerotic lesions in hypercholesterolemic hamsters in vivo, and the extract's antioxidant action, in vitro. Animals were fed on either chow or atherogenic diet during 10 weeks and concomitantly received either water or T. indica L. extract for drinking. Treatment of hypercholesterolemic hamsters with the T. indica pulp fruit extract (5%) led to a decrease in the levels of serum total cholesterol (50%), non-HDL cholesterol (73%) and triglyceride (60%), and to an increase of high-density lipoprotein (HDL) cholesterol levels (61%). In vitro, the extract presented radical scavenging ability, as assessed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radicals assays, and led to decreased lipid peroxidation in serum, as assessed by the thiobarbituric acid reactive substances (TBARS) assay. In vivo, the extract improved the efficiency of the antioxidant defense system, as assessed by the superoxide dismutase, catalase and glutathione peroxidase activities. Together these results indicate the potential of tamarind extracts in diminishing the risk of atherosclerosis development in humans.

Clinical features of patients with posterior cortex epilepsies and predictors of surgical outcome

PURPOSE

Posterior cortex epilepsies (PCEs) encompass a group of epilepsies originating from the occipital, parietal, or occipital border of the temporal lobe, or from any combination of these regions. When their seizures are refractory to pharmacologic treatment, these patients are usually referred for surgery. The aim of our study was to analyze clinical characteristics of all PCE patients referred for surgery from 1994 to 2003, and to search for predictors of surgical outcome.

METHODS

We performed a retrospective analysis of clinical and laboratory data from 81 consecutive refractory PCE patients referred for surgery. Surgical and nonsurgical groups of patients were compared, and detailed analyses of all variables of the surgical cases were performed in the search for predictors of seizure outcome.

RESULTS

Risk factors for PCEs included gliosis (34.56%), malformations of cortical development (33.33%), tumors (8.64%), brain trauma (3.70%), Sturge-Weber disease (4.93%), vascular malformations (3.70%), family history of epilepsy (3.70%), history of CNS infections (2.46%), and low IQ (2.46%). Of the 81 patients, 44 were submitted to surgery at the time of the completion of this study. Surgical treatment was highly effective in improving seizures (p<0.001) when compared with previous pharmacologic treatment alone. Twenty-eight (65.11%) patients became seizure free after surgery versus none in the nonsurgical group. Regarding outcome predictors, patients with shorter duration of epilepsy and those without neurologic abnormalities on clinical examination had higher chances of favorable evolution.

CONCLUSIONS

Surgical treatment is effective for the treatment of PCEs and superior to pharmacologic therapy alone. In our series, shorter duration of epilepsy and normal neurologic examination were the only independent variables that predicted better surgical outcome.

Axonal injury in the cerebral normal-appearing white matter of patients with multiple sclerosis is related to concurrent demyelination in lesions but not to concurrent demyelination in normal-appearing white matter

We assessed axonal injury and demyelination in the cerebral normal-appearing white matter (NAWM) of MS patients in a pilot study using proton magnetic resonance spectroscopic imaging and quantitative magnetization transfer (MT) imaging. Resonance intensities of N-acetylaspartate (NAA) relative to creatine (Cr) were measured in a large central brain volume. NAA/Cr in NAWM was estimated by regression of the NAA/Cr in each voxel against white matter fraction and extrapolation to a white matter fraction of 1. The fractional size of the semi-solid pool (F) was obtained from the binary spin bath model of MT by computing the model parameters from multiple MT-weighted and relaxometry acquisitions. F in NAWM was significantly smaller in the patients [0.109 (0.009)] relative to controls [0.123 (0.007), P = 0.011], but did not differ between RR [0.1085] and SP [0.1087] patients [P > 0.99]. NAA/Cr and F in the NAWM were not correlated (r = 0.16, P > 0.7), mainly due to a lack of variation in F among patients. This may indicate a floor to the extent of myelin pathology that can occur in NAWM before a lesion appears, or that axonal damage is not strictly related to demyelination. The correlation between NAWM NAA/Cr and T2w lesion volume was not significant (P > 0.1). However, dividing the lesion volumes by the mean F in T2w lesions resulted in a quantity that correlated well with NAWM NAA/Cr (r = -0.78, P = 0.038), possibly reflecting the association of Wallerian degeneration in the NAWM with axonal transection associated with demyelination within lesions.

Temporal lobe epilepsy surgery in children and adolescents: clinical characteristics and post-surgical outcome

BACKGROUND AND PURPOSE

Temporal lobe epilepsy (TLE) encompasses 10-20% of the cases of intractable epilepsy in pediatric patients. Mesial temporal sclerosis (MTS) can still be encountered in adolescent patients, but is rare in children under 5 years of age. In this paper we report on the surgical outcome of a series of TLE patients ranging in age from 1 to 18 years at the time of operation.

PATIENTS AND METHODS

Thirty-five patients (37 surgeries) with medically intractable TLE were operated upon between January 1996 and December 2002. The following variables were analyzed: age at surgery, age at epilepsy onset, history of an initial precipitating injury, etiology, seizure semiology, interictal and ictal EEG findings, surgical complications, and post-surgical seizure outcome.

RESULTS

There were 68.6% females and 31.3% males, and complex partial seizures (CPS) occurred in 86.5%. The most common etiology was MTS (40%) followed by isolated cortical developmental abnormalities (22.9%). In the age group up to 5 years, cortical development abnormalities predominated, and 71% of these children had multifocal interictal EEG. Patients older than 10 years had more frequently MTS (78.6%) and focal temporal interictal EEG abnormalities. Post-surgical seizure outcome showed that 88.5% of patients were in Engel classes I and II.

CONCLUSIONS

Adolescents with TLE had clinical features, electrographic findings, and seizure outcome similar to those observed in adult patients. However, younger children up to 5 years of age had distinct ictal semiology and different etiological, electrophysiological and outcome profiles, clearly suggesting that they behave as a special subgroup within the TLE.

Surgically amenable epilepsies in children and adolescents: clinical, imaging, electrophysiological, and post-surgical outcome data

BACKGROUND AND PURPOSE

A large number of patients with epilepsy in the pediatric population have medically intractable epilepsy. In this age group seizures are usually daily or weekly, and response to antiepileptic therapy is poor, especially for those with neurological abnormalities and symptomatic epilepsies. However, several authors have already demonstrated similarly favorable long-term post-surgical seizure control when comparing pediatric and adult populations. In this article we aim to report the experience of the Ribeirão Preto Epilepsy Surgery Program in pediatric epilepsy surgery.

PATIENTS AND METHODS

We analyzed 107 patients with medically intractable epilepsy operated on between July 1994 and December 2002, considering age at surgery, seizure type, pathological findings, and seizure outcome. All data were prospectively collected according to protocols previously approved by the institution ethics committee.

RESULTS

We analyzed a total of 115 operations performed in 107 patients. There was no difference in sex distribution. Complex partial seizures occurred in 31.4% of the patients, followed by tonic seizures (25.9%), focal motor seizures (15.4%), and infantile spasms (13.3%). The most common etiologies were cortical developmental abnormalities (25.2%), tumors (16.8%), mesial temporal sclerosis (15.9%), Rasmussen syndrome (6.5%), and tuberous sclerosis (6.5%). Overall post-surgical seizure outcome showed 67.2% of the patients within Engel classes I and II, reaching 75.0% when patients with callosotomies were excluded.

CONCLUSIONS

Post-surgical seizure control in the pediatric population is similar to that in adult patients, despite the fact that epilepsies in this age group are more frequently of extratemporal origin, suggesting that surgery should be considered in children as soon as intractability is determined.

The interaction of flavonoids with mitochondria: effects on energetic processes

The study addressed aspects of energetics of isolated rat liver mitochondria exposed to the flavonoids quercetin, taxifolin, catechin and galangin, taking into account influences of the 2,3 double bond/3-OH group and 4-oxo function on the C-ring, and o-di-OH on the B-ring of their structures, as well as mitochondrial mechanisms potentially involved in cell necrosis and apoptosis. The major findings/hypothesis, were: The 2,3 double bond/3-OH group in conjugation with the 4-oxo function on the C-ring in the flavonoid structure seems favour the interaction of these compounds with the mitochondrial membrane, decreasing its fluidity either inhibiting the respiratory chain of mitochondria or causing uncoupling; while the o-di-OH on the B-ring seems favour the respiratory chain inhibition, the absence of this structure seems favour the uncoupling activity. The flavonoids not affecting the respiration of mitochondria, induced MPT. The ability of flavonoids to induce the release of mitochondria-accumulated Ca(2+) correlated well with their ability to affect mitochondrial respiration on the one hand, and their inability to induce MPT, on the other. The flavonoids causing substantial respiratory chain inhibition or mitochondrial uncoupling, quercetin and galangin, respectively, also decreased the mitochondrial ATP levels, thus suggesting an apparent higher potential for necrosis induction in relation to the flavonoids inducing MPT, taxifolin and cathechin, which did not decrease significantly the ATP levels, rather suggesting an apparent higher potential for apoptosis induction.

Cortical malformations are associated with a rare polymorphism of cellular prion protein

Studies in animals lacking the cellular prion protein (PrP(c)) gene (Prnp) showed higher neuronal excitability in vitro and increased sensitivity to seizures in vivo. The authors previously reported a rare polymorphism at codon 171 (Asn-->Ser) of human Prnp to be associated with mesial temporal lobe epilepsy related to hippocampal sclerosis. They demonstrated that the same variant allele is also associated with symptomatic epilepsies related to different forms of malformations of cortical development.

CG, Assirati Jr. JA, Santos AC, Sakamoto AC. Memory tests are not good predictors of surgical outcome in patients with mesial temporal Lobe epilepsy associated with hippocampal sclerosis

Introduction: One of the objectives of pre-surgical evaluation in mesial temporal epilepsy associated to hippoocampal sclerosis is the identification of patients with bad surgical prognosis for seizure control. At least theoretically, neuropsychological tests could be used in this venue. Objective: To evaluate whether verbal and visual memory tests can be used as isolate predictors of the post-surgical seizure outcome in patients with mesial temporal lobe epilepsy associated with hippocampal sclerosis refractory to pharmacological treatment. Methods: In a retrospective cohort study using the control of epileptic seizures as end-point, we evaluated 187 patients and calculated the correlation of clinical variables, cognitive evaluation, neuroimaging data, demographic data and electrophysiological findings with the result of seizure control after lobectomy in these patients. Results: An unfavorable prognosis during the postoperative period was observed only in association with low visual reproduction scores (visual memory). However, after Bonferroni correction, which was necessary to reduce the chance of type I error, this result was found to be spurious. Conclusion: We conclude that neuropsychological tests of verbal and visual memory such as those used in the routine presurgical evaluation of our patients with temporal lobe epilepsy are not good isolated predictors of surgical outcome.

MIB-1 labeling index in astrocytic tumors--a clinicopathologic study

BACKGROUND

Although neuroimage and surgical techniques have improved substantially, the prognosis of patients with astrocytic tumors remains unchanged. The purpose of this study was to evaluate the proliferative activity in astrocytic tumors in different grades of malignancy and correlate it to other clinical features.

PATIENTS AND METHODS

From archival paraffin-embedded surgical specimens of 40 patients of the Ribeirão Preto Medical School with World Health Organization grade II (n = 10), grade III (n = 5) and grade IV astrocytomas (n = 25), the MIB-1 labeling index (LI) was determined using at least a half of the blocks per case. The results were correlated to the biological behavior of the tumors. The aims of this study were to determine the level of MIB-1 LI values (cut-off) that reflect differences in biological behavior of these tumors, the impact on survival of clinical features such as age, tumor location or extension of surgical removal as well as the adjuvant therapy.

RESULTS AND CONCLUSIONS

As expected, a wide range of MIB-1 LI values was disclosed (mean of 2.35% in grade II astrocytomas to 12.28% in glioblastomas). A close relationship was found between MIB-1 LI and survival of patients with astrocytomas according to the histological grade. All but 1 recurrent tumor presented higher MIB-1 LI in the second biopsy, and the mean MIB-1 LI of the patients who died in the immediate postoperative period (n = 7) was higher in comparison to the MIB-1 LI of the respective grade. Postoperative radiation therapy was an important factor that affected the survival of patients with high-grade astrocytomas (p = 0.006). MIB-1 LI cut-off of 3% divided the astrocytomas in 2 groups with significantly different survival (p < 0.001): median survival time of 12 months (low-grade) versus 45 months (high-grade). On the other hand, univariate analysis did not show any correlation between survival and extension of surgical resection (radical versus partial), tumor's location or patient's age at surgery.

In situ evidence of an alternative oxidase and an uncoupling protein in the respiratory chain of Aspergillus fumigatus

Aspergillus fumigatus is an unusual pathogen in immunocompetent individuals; its incidence has increased in the last decades in patients immunocompromised, like those with chronic granulomatosis disease and AIDS. The aim of this study was to identify differences between the respiratory chain of host and the fungus planning to use the later as a pharmacological target. We evaluated respiration, membrane potential and oxidative phosphorylation of mitochondria of the spheroplasts of A. fumigatus in situ, after permeabilization with digitonin. Firstly, a functional respiratory chain (complex I-V) was demonstrated: adenosine 5'-diphosphate (ADP) induced an oligomycin-sensitive transition from resting to phophorylating respiration in the presence of the oxidizable substrates malate, glutamate, alpha-ketoglutarate, pyruvate, dihydroorotate, succinate, N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) and exogenous NADH. In addition, the ability of the fungus to oxidize exogenous NADH, as well as the insensitivity of its respiration to rotenone, in association with the sensitivity to flavone, indicate the presence of an alternative NADH-ubiquinone oxidoreductase; the partial sensitivity of respiration to antimycin A and cyanide, in association with the sensitivity to benzohydroxamic acid, indicates the presence of an alternative oxidase. The fatty acid-uncoupled respiration was partly reversed by bovine serum albumin (BSA) and guanosine 5'-triphosphate (GTP) and was insensitive to either carboxyatractyloside or ADP. These results, together with evidences obtained using antibodies raised against uncoupling protein (UCP) from potato, indicate in addition, the presence of an uncoupling protein in the respiratory chain of A. fumigatus.

Regional variations in normal brain shown by quantitative magnetization transfer imaging

A quantitative magnetization transfer imaging (qMTI) study, based on a two-pool model of magnetization transfer, was performed on seven normal subjects to determine, on a regional basis, normal values for the pool sizes, exchange, and relaxation parameters that characterize the MT phenomenon. Regions were identified on high-resolution anatomical scans using a combination of manual and automatic methods. Only voxels identified as pure tissue at the resolution of the quantitative scans were considered for analysis. While no left/right differences were observed, significant differences were found among white-matter regions and gray-matter regions. These regional differences were compared with existing cytoarchitectural data. In addition, the pattern and magnitude of the regional differences observed in white matter was found to be different from that reported previously for an alternative putative MRI measure of myelination, the 10-50-ms T2 component described as myelin water.

Discordant phenotypes in first cousins withUBE3Aframeshift mutation

Mutations have been found in the UBE3A gene (E6-AP ubiquitin protein ligase gene) in many Angelman syndrome (AS) patients with no deletion, no uniparental disomy, and no imprinting defect. UBE3A mutations are more frequent in familial than in sporadic patients and the mutations described so far seem to cause similar phenotypes in the familial affected cases. Here we describe two first cousins who have inherited the same UBE3A frameshift mutation (duplication of GAGG in exon 10) from their asymptomatic mothers but present discordant phenotypes. The proband shows typical AS features. Her affected cousin shows a more severe phenotype, with asymmetric spasticity that led originally to a diagnosis of cerebral palsy. Proband's brain MRI shows mild cerebral atrophy while her cousin's brain MRI shows severe brain malformation. This family demonstrates that, although brain malformation is unusual in AS, presence of a brain malformation does not exclude the diagnosis of AS. Also, this UBE3A mutation was transmitted from the cousin's grandfather to only two sisters among eight full siblings, raising the hypothesis of mosaicism for this mutation.

The size and prevalence of the cavum septum pellucidum are normal in subjects with panic disorder

Panic disorder is thought to involve dysfunction in the septohippocampal system, and the presence of a cavum septum pellucidum might indicate the aberrant development of this system. We compared the prevalence and size of cavum septum pellucidum in 21 patients with panic disorder and in 21 healthy controls by magnetic resonance imaging. The length of the cavum septum pellucidum was measured by counting the number of consecutive 1-mm coronal slices in which it appeared. A cavum septum pellucidum of >6 mm in length was rated as large. There was no significant difference in the proportion of patients (16 of 21 or 76.2%) and controls (18 of 21 or 85.7%) with a cavum septum pellucidum (P=0.35, Fisher's exact test, one-tailed), and no members of either group had a large cavum septum pellucidum. The mean cavum septum pellucidum rating in the patient and control groups was 1.81 (SD=1.50) and 2.09 (SD=1.51), respectively. There were also no significant differences between groups when we analyzed cavum septum pellucidum ratings as a continuous variable (U=196.5; P=0.54). Across all subjects there was a trend towards a higher prevalence of cavum septum pellucidum in males (100%, 10 of 10) than females (75%, 24 of 32; P=0.09, Fisher's exact test, one-tailed). Thus, we conclude that, while panic disorder may involve septo-hippocampal dysfunction, it is not associated with an increased prevalence or size of the cavum septum pellucidum.

Silencing of Phosphonate-Gadolinium Magnetic Resonance Imaging Contrast by Hydroxyapatite Binding

RATIONALE AND OBJECTIVES

GdDOTP5- is a highly charged, bone-seeking paramagnetic complex that could potentially detect bone lesions by magnetic resonance imaging (MRI). To date, its pharmacokinetics, effects on organ relaxivity, and interaction with hydroxyapatite (HA) has not been described.

METHODS

Liver, kidney, and bone MRI images were obtained on male white rabbits after the administration of GdDOTP5- or a gold standard MRI contrast agent, GdDTPA2-. Parallel in vitro experiments quantified the effect of HA binding on GdDOTP5- -induced changes in relaxivity.

RESULTS

The 2 compounds showed similar MRI enhancements in visceral tissues, but no enhancement of bone was evident with GdDOTP5- despite confirmation of bone and HA binding of the radioactive 153SmDOTP5- and 111InDOTP5- derivatives. In vitro experiments demonstrated that GdDOTP5--induced changes in relaxivity were silenced upon HA binding but could be recovered by acid elution of the complex.

CONCLUSIONS

HA binding assays revealed that GdDOTP5- is essentially MR silent when bound to bone, likely because of the exclusion of all outer sphere water molecules from the surface of the complex. These data suggest a novel strategy for creating highly sensitive, switchable MRI contrast agents.

Surgical outcome in mesial temporal sclerosis correlates with prion protein gene variant

BACKGROUND

Mesial temporal lobe epilepsy related to hippocampal sclerosis (MTLE-HS) is the most common surgically remediable epileptic syndrome. Ablation of the cellular prion protein (PrP(c)) gene (PRNP) enhances neuronal excitability of the hippocampus in vitro and sensitivity to seizure in vivo, indicating that PrP(c) might be related to epilepsy.

OBJECTIVE

To evaluate the genetic contribution of PRNP to MTLE-HS.

METHODS

The PRNP coding sequence of DNA from peripheral blood cells of 100 consecutive patients with surgically treated MTLE-HS was compared to that from a group of healthy controls adjusted for sex, age, and ethnicity (n = 180). The presence of PRNP variant alleles was correlated with clinical and presurgical parameters as well as surgical outcome.

RESULTS

A variant allele at position 171 (Asn-->Ser), absent in controls, was found in heterozygosis (Asn171Ser) in 23% of patients (p < 0.0001). The PRNP genotypes were not correlated with any clinical or presurgical data investigated. However, patients carrying the Asn171Ser variant had a five times higher chance of continuing to have seizures after temporal lobectomy (95% CI 1.65 to 17.33, p = 0.005) than those carrying the normal allele. At 18 months after surgery, 91.8% of patients with the normal allele at codon 171 were seizure free, in comparison to 68.2% of those carrying Asn171Ser (p = 0.005).

CONCLUSIONS

The PRNP variant allele Asn171Ser is highly prevalent in patients with medically untreatable MTLE-HS and influences their surgical outcome. The results suggest that the PRNP variant allele at codon 171 (Asn171Ser) is associated with epileptogenesis in MTLE-HS.

A proposed sequence of events for cadmium-induced mitochondrial impairment

Cadmium is a very important environmental toxicant, the cytotoxicity mechanism of which is likely to involve mitochondria as a target. In the present study we addressed the cause/effect relationship between the multiple cadmium-induced responses involving the mitochondrial energetic and oxidative status. Assays were performed with succinate-energized rat liver mitochondria incubated with 5 microM CdCl(2) for 0-25 min, in the absence or presence, respectively, of N-ethylmaleimide (NEM), butylhydroxytoluene (BHT), ruthenium red (RR), and cyclosporine A+ADP. A sequence of events accounting for cadmium-induced mitochondrial impairment is proposed, beginning with an apparent interaction of Cd(2+) with specific protein thiols in the mitochondrial membrane, which stimulates the cation's uptake via the Ca(2+) uniporter, and is followed by the onset of mitochondrial permeability transition (MPT); both effects dissipate the transmembrane electrical potential (Deltapsi), causing uncoupling, followed by an early depression of mitochondrial ATP levels. The respiratory chain subsequently undergoes inhibition, generating reactive oxygen species which together with iron mobilized by the cation, cause late, gradual mitochondrial membrane lipid peroxidation.

Shannon entropy applied to the analysis of event-related fMRI time series

Event-related functional magnetic resonance imaging (ER-fMRI) refers to the blood oxygen level-dependent (BOLD) signal in response to a short stimulus followed by a long period of rest. These paradigms have become more popular in the last few years due to some advantages over standard block techniques. Most of the analysis of the time series generated in such exams is based on a model of specific hemodynamic response function. In this paper we propose a new method for the analysis of ER-fMRI based in a specific aspect of information theory: the entropy of a signal using the Shannon formulation, which makes no assumption about the shape of the response. The results show the ability to discriminate between activated and resting cerebral regions for motor and visual stimuli. Moreover, the results of simulated data show a more stable pattern of the method, if compared to typical algorithms, when the signal to noise ratio decreases.