Neural dynamics of semantic categorization in semantic variant of primary progressive aphasia.

Semantic representations are processed along a posterior-to-anterior gradient reflecting a shift from perceptual (e.g., it has eight legs) to conceptual (e.g., venomous spiders are rare) information. One critical region is the anterior temporal lobe (ATL): patients with semantic variant primary progressive aphasia (svPPA), a clinical syndrome associated with ATL neurodegeneration, manifest a deep loss of semantic knowledge. We test the hypothesis that svPPA patients perform semantic tasks by over-recruiting areas implicated in perceptual processing. We compared MEG recordings of svPPA patients and healthy controls during a categorization task. While behavioral performance did not differ, svPPA patients showed indications of greater activation over bilateral occipital cortices and superior temporal gyrus, and inconsistent engagement of frontal regions. These findings suggest a pervasive reorganization of brain networks in response to ATL neurodegeneration: the loss of this critical hub leads to a dysregulated (semantic) control system, and defective semantic representations are seemingly compensated via enhanced perceptual processing.

The diversity of zinc-finger genes on human chromosome 19 provides an evolutionary mechanism for defense against inherited endogenous retroviruses.

Endogenous retroviruses (ERVs) are remnants of ancient retroviral infections of the germ line that can remain capable of replication within the host genome. In the soma, DNA methylation and repressive chromatin keep the majority of this parasitic DNA transcriptionally silent. However, it is unclear how the host organism adapts to recognize and silence novel invading retroviruses that enter the germ line. Krueppel-Associated Box (KRAB)-associated protein 1 (KAP1) is a transcriptional regulatory factor that drives the epigenetic repression of many different loci in mammalian genomes. Here, we use published experimental data to provide evidence that human KAP1 is recruited to endogenous retroviral DNA by KRAB-containing zinc-finger transcription factors (TFs). Many of these zinc-finger genes exist in clusters associated with human chromosome 19. We demonstrate that these clusters are located at hotspots for copy number variation (CNV), generating a large and continuing diversity of zinc-finger TFs with new generations. These zinc-finger genes possess a wide variety of DNA binding affinities, but their role as transcriptional repressors is conserved. We also perform a computational study of the different ERVs that invaded the human genome during primate evolution. We find candidate zinc-finger repressors that arise in the genome for each ERV family that enters the genomes of primates. In particular, we show that those repressors that gained their binding affinity to retrovirus sequences at the same time as their targets invaded the human lineage are preferentially located on chromosome 19 (P-value: 3 × 10(-3)).

Percutaneous radiofrequency ablation of small renal cell carcinoma: technique, complications, and outcomes.

Imaging-guided radiofrequency ablation (RFA) is an option for treatment in patients with early-stage small renal cell carcinomas (RCCs). RFA has been introduced to treat focal renal tumors, particularly incidental lesions <3 cm in elderly patients and those with comorbid conditions. Other uses have included treatment in patients with von Hippel-Lindau syndrome and other diseases that predispose patients to multiple renal carcinomas, where renal parenchymal preservation is desired. It appears that this technique has a low complication rate, preserves renal function, is well tolerated by the patients, and, in a high percentage of patients, can eradicate small renal tumors. Techniques, patient selection, complications, and results are discussed.

Percutaneous imaging-guided radiofrequency ablation of small renal cell carcinoma: techniques and outcomes of 24 treatment sessions in 18 consecutive patients.

PURPOSE: To evaluate the early clinical experience associated with percutaneous imaging-guided radiofrequency ablation (RFA) in patients with renal cell carcinoma (RCC). METHODS: Eighteen consecutive patients with RCC were treated with percutaneous RFA sessions (24 sessions for 19 solitary RCC in 18 patients: 15 patients underwent a single RFA session, 3 had 2 sessions and one 3 sessions). Treatment indications were localized, solid renal mass <4.5 cm, comorbidities precluding surgery, high operation risk, and refusal to perform surgery. During 23 sessions, RFA was performed using computed tomography (CT) guidance and in one session it was guided by ultrasonography. The average patient age was 76.8±7.6 years (range 64-89), and the average renal mass size 3.3 ±0.7 cm (range 2.0-4.5). Follow-up imaging was performed at 3- and 6-month intervals and yearly thereafter. Successful treatment was defined as lack of enhancement of the treated region on follow-up CT studies. RESULTS: RFA was technically successful in all patients. After the last imaging control, 17 of the 19 tumors were completely necrotic according to the imaging criteria (the secondary clinical success rate was 89.5%). Thirteen tumors were not visible on the first follow-up imaging control (the primary clinical success rate was 68.4% - 13 of 19). In 4 of the 6 patients residual tumors were successfully re-ablated, while in 2 patients repeated RFAs were not performed at the time of writing this report. Five patients (20.8%) developed treatmentrelated complications, including mild pain, large perirenal abscess, mild perirenal hematoma and transient elevation of the white blood cell count. The mean follow-up period was 25.3±16.8 months (range 1-51). CONCLUSION: RFA is effective and safe treatment option of exophytic RCC <5 cm in diameter in patients not suitable for surgery due to serious concomitant diseases or advanced age.

Ion source for tests of ion behavior in the Karlsruhe tritium neutrino experiment beam line.

An electron-impact ion source based on photoelectron emission was developed for ionization of gases at pressures below 10(-4) mbar in an axial magnetic field in the order of 5 T. The ion source applies only dc fields, which makes it suitable for use in the presence of equipment sensitive to radio-frequency (RF) fields. The ion source was successfully tested under varying conditions regarding pressure, magnetic field, and magnetic-field gradient, and the results were studied with the help of simulations. The processes in the ion source are well understood, and possibilities for further optimization of generated ion currents are clarified.

Arterial embolization of uterine fibroids.

PURPOSE: the aim of this study was to analyze outcomes in a series of patients with symptomatic uterine fibroids who had undergone endovascular arterial embolization. METHODS: analysis included 36 patients with uterine fibroids and average age of 38.5 years, with bilateral endovascular embolization of fibroid-feeding arteries. Solitary uterine fibroids were present in 20 (56%) patients, and multiple in 16 (44%) patients. The patients were followed up to one year after embolization. RESULTS: in the subgroup of patients with solitary uterine fibroids, 6 months after the embolization, the volume of uterine fibroids was reduced to 50% in 16 patients, and to 38% in 4 patients. After one year, the volume of uterine fibroids was reduced to 50% in all 36 patients. In the subgroup of patients with multiple uterine fibroids, 6 months after the embolization, the volume of uterine fibroids was reduced to 50% in 10 patients, and to 36% in 6 patients. After one year, the volume of uterine fibroids was reduced to 50% in 14 patients, while in 2 patients the reduction of the volume remained 36%. After one year, all patients became symptomless. CONCLUSION: the results of this case series show high efficacy of endovascular embolization of uterine fibroids: with a minimally invasive treatment, the volume of uterine fibroids is halved and symptoms disappear, obviating the need for a surgical intervention.

[Intra-arterial embolisation of uterine fibroma].

UNLABELLED: Uterine fibroid are benign tumors that consist most of the tumor occurrences in pelvic cavity of women. Possible courses of treatment include: medicament treatment, surgical and new intra-arterial embolisation method. The aim of the paper is to present achieved results in intra-arterial embolisation treatment of Uterine fibroid. MATERIAL AND METHODS: A prospective study was performed in the period from October 2007 until October 2008. It included 36 women with symptomatic uterine fibroid. They were treated by intra-arterial embolisation. All patients had control MRI examinations after treatment. Embolisation was performed by "cross-over" technique, using bilateral punction of femoral arteries, a selective catheterization a. uterine, and application of 750-900m Bead Blocks. RESULTS: Average age of patients was 38.5 years. The most of fibroids had intramural localization (39%). solitary fibroids were seen in 56% of patients, multiple in 44%. Gynecological hemorrhage was the leading symptom with 34 patients (94%). One year after receiving intra-arterial embolisation treatment, fibroid regression of 50% was registered in all patients. There were no serious complications noted in our study, with the exception of postembolisation syndrome which occurred in 11 (30%) patients in a relatively mild form. CONCLUSION: Intra-arterial embolisation of uterine fibroma is a method that in large percent of patients removes symptoms of uterine fibroma presence, prevents its growth, and safely helps women enter menopause when activity of hormone dependant tumor ceases.

[Occurrence and risk factor for development of pancreatitis and asymptomatic hyperamylasemia following endoscopic retrograde cholangiopancreatography--our experiences].

INTRODUCTION: Chronic pancreatitis is defined as chronic inflammatory lesion of pancreatic parenchyma leading to destruction and fibrosis of exocrine pancreas. Endoscopic retrograde cholangiopancreatography (ERCP) is the most sensitive and specific method for detection of morphological alterations in chronic pancreatitis. ERCP is inevitably associated to post-ERCP acute pancreatitis, as well as hyperamilasemia. STUDY AIM: This study aims to determine frequency of post-ERPC pancreatitis and asymptomatic hyperamilasemia. STUDY METHODS: We have studied 160 patients who underwent ERCP in Institute of Digestive Diseases, Clinical Centre of Serbia in Belgrade. Data regarding cholecystectomy, papillotomy, peripapillary diverticulosis, Oddi's sphincter hypertension, choledoch canulation and diameter, Wirsung duct canulation, minor duodenal papilla patency, anomalies of BP junction, as well as chronic pancreatitis has been analysed and correlated with eventual development of post-ERCP pancreatitis and asymptomatic hyperamilasemia. RESULTS: Asymptomatic hyperamilasemia was determined in 51 subjects (31.9%), while pancreatitis has been developed in 5 patients (3.1%) subsequent to ERCP. It has been proofed that Wirsung duct canulation plays significant role in development of post-ERCP complications. CONCLUSION: Although numerous factors may potentially contribute to development of post-ERCP pancreatitis, none of them, with the exception of Wirsung duct canulation, has been determined to play significant role in development of these complications.

Selective blockade of metabotropic glutamate receptor subtype 5 is neuroprotective.

We have used potent and selective non-competitive antagonists of metabotropic glutamate receptor subtype 5 (mGlu5) -- 2-methyl-6-phenylethynylpyridine (MPEP), [6-methyl-2-(phenylazo)-3-pyridinol] (SIB-1757) and [(E)-2-methyl-6-(2-phenylethenyl)pyridine] (SIB-1893) - to examine whether endogenous activation of this particular metabotropic glutamate receptor subtype contributes to neuronal degeneration. In cortical cultures challenged with N-methyl-D-aspartate (NMDA), all three mGlu5 receptor antagonists were neuroprotective. The effect of MPEP was highly specific because the close analogue, 3-methyl-6-phenylethynylpyridine (iso-MPEP), which did not antagonize heterologously expressed mGlu5 receptors, was devoid of activity on NMDA toxicity. Neuroprotection by mGlu5 receptor antagonists was also observed in cortical cultures challenged with a toxic concentration of beta-amyloid peptide. We have also examined the effect of mGlu5 receptor antagonists in in vivo models of excitotoxic degeneration. MPEP and SIB-1893 were neuroprotective against neuronal damage induced by intrastriatal injection of NMDA or quinolinic acid. These results indicate that mGlu5 receptors represent a suitable target for novel neuroprotective agents of potential application in neurodegenerative disorders.

Selective activation of mGlu4 metabotropic glutamate receptors is protective against excitotoxic neuronal death.

Activation of group III metabotropic glutamate receptors (mGluR4, mGluR6, mGluR7, and mGluR8) has been established to be neuroprotective in vitro and in vivo. To disclose the identity of the receptor subtype(s) that exert(s) the protective effect, we have used group III agonists in combination with mGluR4 subtype-deficient mice (-/-). In cortical cultures prepared from wild-type (+/+) mice and exposed to a toxic pulse of NMDA, the selective group III agonist (+)-4-phosphonophenylglycine [(+)-PPG] reversed excitotoxicity with an EC(50) value of 4.9 microm, whereas its enantiomer (-)-PPG was inactive. This correlated closely with the potency of (+)-PPG in activating recombinant mGluR4a. In cortical neurons from -/- mice, (+)-PPG showed no protection against the NMDA insult up to 300 microm, whereas group I/II mGluR ligands still retained their protective activity. Classical group III agonists (l-2-amino-4-phosphonobutyrate and l-serine-O-phosphate) were also substantially neuroprotective against NMDA toxicity in +/+ and heterozygous (+/-) cultures but were inactive in -/- cultures. Interestingly, -/- cultures were more vulnerable to low concentrations of NMDA and showed higher extracellular glutamate levels compared with +/+ cultures. We have also examined neurodegeneration induced by intrastriatal infusion of NMDA in wild-type or mGluR4-deficient mice. Low doses of (R,S)-PPG (10 nmol/0.5 microl) substantially reduced NMDA toxicity in +/+ mice but were ineffective in -/- mice. Higher doses of (R,S)-PPG were neuroprotective in both strains of animals. Finally, microdialysis studies showed that intrastriatal infusion of NMDA increased extracellular glutamate levels to a greater extent in -/- than in +/+ mice, supporting the hypothesis that the mGluR4 subtype is necessary for the maintenance of the homeostasis of extracellular glutamate levels.

(R,S)-4-phosphonophenylglycine, a potent and selective group III metabotropic glutamate receptor agonist, is anticonvulsive and neuroprotective in vivo.

Group III metabotropic glutamate receptors (mGluRs) are thought to modulate neurotoxicity of excitatory amino acids, via mechanisms of presynaptic inhibition, such as regulation of neurotransmitter release. Here, we describe (R,S)-4-phosphonophenylglycine (PPG) as a novel, potent, and selective agonist for group III mGluRs. In recombinant cell lines expressing the human receptors hmGluR4a, hmGluR6, hmGluR7b, or hmGluR8a, EC50 values for (R,S)-PPG of 5.2 +/- 0.7 microM, 4.7 +/- 0.9 microM, 185 +/- 42 microM, and 0.2 +/- 0.1 microM, respectively, were measured. The compound showed EC50 and IC50 values of >/=200 microM at group I and II hmGluRs and was inactive at cloned human N-methyl-D-aspartate, alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionate, and kainate receptors (>300 microM). On the other hand, it showed micromolar affinity for a Ca2+/Cl--dependent L-glutamate binding site in rat brain, similar to other phosphono-substituted amino acids like L-2-amino-4-phosphonobutyrate. In cultured cortical neurons, (R, S)-PPG provided protection against a toxic pulse of N-methyl-D-aspartate (EC50 = 12 microM), which was reversed by the group III mGluR antagonist (R,S)-alpha-methylserine-O-phosphate but not by the group II antagonist (2S)-alpha-ethylglutamate. Moreover, (R,S)-PPG protected against N-methyl-D-aspartate- and quinolinic acid-induced striatal lesions in rats and was anticonvulsive in the maximal electroshock model in mice. In contrast to the group III mGluR agonists L-2-amino-4-phosphonobutyrate and L-serine-O-phosphate, (R,S)-PPG showed no proconvulsive effects (2200 nmol i.c.v.). These data provide novel in vivo evidence for group III mGluRs as attractive targets for neuroprotective and anticonvulsive therapy. Also, (R,S)-PPG represents an attractive tool to analyze the roles of group III mGluRs in nervous system physiology and pathology.

A novel splice variant of a metabotropic glutamate receptor, human mGluR7b.

Two splice variants of the human metabotropic glutamate receptor 7, named hmGluR7a and hmGluR7b, were isolated from a human brain cDNA library. The isoforms differ by an out-of-frame insertion of 92 nucleotides close to the C-terminus of the hmGluR7 coding region, hmGluR7a has a length of 915 amino acids and represents the human homolog of the recently cloned rat mGluR7. hmGluR7b is seven amino acids longer and exhibits a novel C-terminus of 23 amino acids in length. RT-PCR analysis demonstrated the existence of mGluR7b transcripts in wild-type mouse brain and its absence in mGluR7 knockout mice. Northern blot analysis indicate that mGluR7 expression is developmentally regulated. It is expressed at high levels in human fetal brain and at a lower level in many regions of adult human brain. Stimulation of hmGluR7b with L-2-amino-4-phosphonobutyrate (L-AP4), L-serine-O-phosphate (L-SOP) or L-glutamate in stably transfected Chinese hamster ovary (CHO) cells depressed forskolin-induced cAMP accumulation, whereas (1S,3R)-1-aminocyclopentane-1,3,-dicarboxylic acid ((1S,3R)-ACPD) and quisqualate (both at 1mM) had no significant effects. As described for rat mGluR7, the rank order of agonist potencies is: L-SOP, L-AP4 > L-glutamate > (1S,3R)-ACPD, quisqualate.

Pharmacological characterization of MCCG and MAP4 at the mGluR1b, mGluR2 and mGluR4a human metabotropic glutamate receptor subtypes.

The two reported metabotropic glutamate receptor (mGluR) antagonists, alpha-methyl-cyclopropyl glycine (MCCG) and alpha-methyl-aminophosphonobutyrate (MAP4) were tested on the mGluR1b, mGluR2 and mGluR4a subtypes of human mGluRs. Neither MCCG (500 microM) nor MAP4 (500 microM) antagonized the activation of mGluR1b by 10 microM quisqualate. MCCG was found to potently antagonize the action of 30 microM (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid [(1S,3R)-ACPD] at mGluR2 (IC50 = 87.5 microM; apparent Kd = 25 microM) but did not block the action of 1 microM S-2-amino-4-phosphonobutyric acid at mGluR4a (IC50 >> 1 mM). MAP4 was found to be a weak antagonist or partial agonist at mGluR4a (IC50 > 500 microM) and, less potently, also antagonized the action of 30 microM (1S,3R)-ACPD) at mGluR2 (IC50 approximately 2 mM).

Molecular cloning, functional expression and pharmacological characterization of the human metabotropic glutamate receptor type 2.

A cDNA encoding the human metabotropic glutamate receptor type 2 (hmGluR2) was isolated from human brain cDNA libraries by cross-hybridization with rat mGluR2 probes. The deduced amino acid sequence of the human mGluR2 receptor consists of 872 residues and shows a sequence identity of 97% to the amino acid sequence of rat mGluR2. Northern blot analyses showed that hmGluR2 is widely expressed in different regions of the adult brain as well as in fetal human brain. Genomic Southern blotting localized the mGluR2 gene to human chromosome 3. Chinese hamster ovary (CHO) cells stably transfected with the cloned hmGluR2 cDNA exhibit agonist induced depression of forskolin-stimulated cAMP accumulation. A direct comparison of CHO cells stably expressing human and rat mGluR2 with five agonists revealed the same rank order of potency [(2S,3S,4S)-alpha-(carboxycyclopropyl)-glycine >> (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid = L-glutamate >> quisqualate = L-2-amino-4-phosphonobutyric acid] and similar EC50 values for both homologous receptors. (R,S)-alpha-methyl-4-carboxyphenylglycine, a reported antagonist at some mGluR subtypes, reduced the depression of forskolin-induced cAMP accumulation by (1S,3R)-ACPD in both human and rat mGluR2.

Molecular cloning, functional expression and pharmacological characterization of the human metabotropic glutamate receptor type 4.

A cDNA encoding the human metabotropic glutamate receptor type 4 (hmGluR4) was isolated from human brain cDNA libraries by cross-hybridization with rat mGluR4 probes. The deduced amino acid sequence of human mGluR4 consists of 912 residues and shows a sequence identity of 96% to the amino acid sequence of rat mGluR4. Northern blot analyses indicate that hmGluR4 is strongly expressed in the cerebellum of the adult human brain but also at low levels in hippocampus, hypothalamus and thalamus. Stimulation of hmGluR4 with L-2-amino-4-phosphonobutyrate (L-AP4), L-serine-O-phosphate (L-SOP), L-glutamate or (1S,3R)-1-aminocyclo-pentane-1,3-dicarboxylic acid ((1S,3R)-ACPD) in stably transfected Chinese hamster ovary (CHO) cells depressed forskolin-induced cAMP accumulation, whereas quisqualate (0.5 mM) was ineffective. The rank order of agonist potencies is: L-AP4 > L-SOP > L-glutamate > (1S,3R)-ACPD >> quisqualate. (R,S)-alpha-methyl-4-carboxyphenylglycine (1 mM), a reported antagonist at some mGluR subtypes, did not reduce the depression of forskolin-induced cAMP accumulation by L-AP4.

[A case of brain malformation without a change in skull configuration]. / Ein Fall von Hirnfehlbildung ohne Veränderung der Schädelkonfiguration.

The brain of a 5-months old female baby was investigated. The baby died following operation for myelomeningocystocoele of the lumbosacral region. The post mortem finding showed that there were no other malformations present besides the changes at the level of the central nervous system. Lack of the falx was observed on the dura mater, while the tentorium cerebelli was well developed. The cerebrum was on the whole of a bulbular form with a larger transversal diameter and was not divided into 2 hemispheres. A complete lack of the rhinencephalon was observed on the basal aspect of the brain. Between the dorsal surface of the cerebral trunk and the cerebrum there was a specious transversal fissure through which a considerable part of the choroidal plexus emerged from the ventricle and was positioned extraventricularly. The posterior edge of this fissure is formed by the commissura hippocampi behind which there are well developed gyri dentati which are interconnected in the medial line. The cerebellum is normally developed but antepositioned, with a considerably pronounced vermis cerebelli. Frontal sections of the brain showed an emphasised contrast between the gray and the white brain substance which is indicative of a higher level of brain maturity. The third brain ventricle, as well as the frontal horns of the lateral ventricle were missing, and there was a developed central common cavity and the temporal horns. The basal ganglia were merged with the central gray matter spread in a transversal direction which was separated from the cortex by an arc-formed white brain substance.