Neuron-specific knock-down of SMN1 causes neuron degeneration and death through an apoptotic mechanism.

Spinal muscular atrophy is a devastating disease that is characterized by degeneration and death of a specific subclass of motor neurons in the anterior horn of the spinal cord. Although the gene responsible, survival motor neuron 1 (SMN1), was identified 20 years ago, it has proven difficult to investigate its effects in vivo. Consequently, a number of key questions regarding the molecular and cellular functions of this molecule have remained unanswered. We developed a Caenorhabditis elegans model of smn-1 loss-of-function using a neuron-specific RNA interference strategy to knock-down smn-1 selectively in a subclass of motor neurons. The transgenic animals presented a cell-autonomous, age-dependent degeneration of motor neurons detected as locomotory defects and the disappearance of presynaptic and cytoplasmic fluorescent markers in targeted neurons. This degeneration led to neuronal death as revealed by positive reactivity to genetic and chemical cell-death markers. We show that genes of the classical apoptosis pathway are involved in the smn-1-mediated neuronal death, and that this phenotype can be rescued by the expression of human SMN1, indicating a functional conservation between the two orthologs. Finally, we determined that Plastin3/plst-1 genetically interacts with smn-1 to prevent degeneration, and that treatment with valproic acid is able to rescue the degenerative phenotype. These results provide novel insights into the cellular and molecular mechanisms that lead to the loss of motor neurons when SMN1 function is reduced.

Kainic acid-induced albumin leak across the blood-brain barrier facilitates epileptiform hyperexcitability in limbic regions.

OBJECTIVE: Systemic administration of kainic acid (KA) is a widely used procedure utilized to develop a model of temporal lobe epilepsy (TLE). Despite its ability to induce status epilepticus (SE) in vivo, KA applied to in vitro preparations induces only interictal-like activity and/or isolated ictal discharges. The possibility that extravasation of the serum protein albumin from the vascular compartment enhances KA-induced brain excitability is investigated here. METHODS: Epileptiform activity was induced by arterial perfusion of 6 µm KA in the in vitro isolated guinea pig brain preparation. Simultaneous field potential recordings were carried out bilaterally from limbic (CA1, dentate gyrus [DG], and entorhinal cortex) and extralimbic regions (piriform cortex and neocortex). Blood-brain barrier (BBB) breakdown associated with KA-induced epileptiform activity was assessed by parenchymal leakage of intravascular fluorescein-isothiocyanate albumin. Seizure-induced brain inflammation was evaluated by western blot analysis of interleukin (IL)-1ß expression in brain tissue. RESULTS: KA infusion caused synchronized activity at 15-30 Hz in limbic (but not extralimbic) cortical areas, associated with a brief, single seizure-like event. A second bolus of KA, 60 min after the induction of the first ictal event, did not further enhance excitability. Perfusion of serum albumin between the two administrations of KA enhanced epileptiform discharges and allowed a recurrent ictal event during the second KA infusion. SIGNIFICANCE: Our data show that arterial KA administration selectively alters the synchronization of limbic networks. However, KA is not sufficient to generate recurrent seizures unless serum albumin is co-perfused during KA administration. These findings suggest a role of serum albumin in facilitating acute seizure generation.

Development of a prediction model of adverse events after stent placement for esophageal cancer.

BACKGROUND AND AIMS: Self-expandable metal stent (SEMS) positioning is the recommended method for palliation of dysphagia from esophageal cancer, although it is not adverse event-free. The present study was aimed at identifying predictors for adverse events and at proposing a statistical model to predict them. METHODS: We performed a retrospective analysis of a prospectively collected database. All patients who underwent SEMS placement for stricture due to esophageal cancer between 2002 and 2011 in a tertiary-care center were identified. Multivariable regression analysis in the presence of competing risk events was used to identify factors associated with SEMS-related adverse events and to build a prediction model. RESULTS: A total of 267 patients were included. According to the competing risk regression analysis, only 2 variables were significantly associated with the risk of SEMS-related adverse events: prior chemoradiotherapy (CRT), yielding a hazard ratio (HR) of 1.687 (95% confidence interval [CI], 1.076-2.644), and the SEMS length (HR 0.884; 95% CI, 0.798-0.980) for every 10-mm length increase. Based on the estimated probability curves, after 4 months from SEMS placement, the probability of an adverse event in patients who did receive prior CRT was 50.9% compared with 34.4% in those who did not receive prior therapy, which was reduced to 9.2% and 15.1%, respectively, if a 180 mm-length stent was used. The ability of the predictive model to differentiate between patients who did and did not experience the adverse event was moderate (c-index: 0.617). CONCLUSION: The rate of SEMS-related adverse events was higher in patients with previous CRT and lower in patients receiving longer stents. Both factors were used to build an accurate predictive model.

Flexible endoscopic treatment for Zenker's diverticulum: a systematic review and meta-analysis.

BACKGROUND AND AIMS: Flexible endoscopic septum division (FESD) is a rapidly evolving technique for the treatment of Zenker's diverticulum (ZD). The aim was to perform a systematic review and meta-analysis of the literature focusing on FESD for ZD, including an in-depth evaluation of its efficacy, safety, and limitations. METHODS: A comprehensive literature search was completed to identify papers that examined the efficacy and safety of FESD for ZD. Demographic, clinical, and technical information was retrieved. Main outcomes were extracted, pooled, and analyzed. Heterogeneity among studies was assessed using the I(2) statistic. A random effect model was used as the pooling method in cases of high heterogeneity; otherwise the fixed effect model was applied. Meta-regression was also performed. Main outcomes such as rates of success, adverse events, and recurrences were evaluated. RESULTS: Twenty studies with a total of 813 patients were selected. The pooled success, adverse events, and recurrence rates were 91% (95% confidence interval [CI], 86%-95%; I(2) = 69.5%), 11.3% (95% CI, 8%-16%; I(2) = 64%), and 11% (95% CI, 8%-15%; I(2) = 38.4%), respectively. Substantial heterogeneity across studies was found. However, for success rates, excluding 3 studies reduced heterogeneity to non-significant rates [I(2) = 25.6%; P = .154]. Adverse event rates decreased with larger samples (coefficient, -0.0123; 95% CI, -0.03 to -0.003; P = .017), whereas recurrence rates increased (coefficient, 0.006; 95% CI, -0.0010 to 0.0125; P = .093). Year of publication was negatively associated with success rate, whereas the opposite pattern was found for recurrence rates. CONCLUSIONS: FESD is a feasible, safe, and effective treatment for symptomatic ZD, with low adverse event and recurrence rates.

Adherence to WCRF/AICR lifestyle recommendations for cancer prevention and the risk of Barrett's esophagus onset and evolution to esophageal adenocarcinoma: results from a pilot study in a high-risk population.

PURPOSE: While adherence to the World Cancer Research Fund (WCRF) guidelines on lifestyle and cancer was recently proven to be associated with an increased risk of esophageal cancer, no investigation has yet been carried out on its role on Barrett's esophagus (BE) development and its progression to esophageal adenocarcinoma (EAC). The primary aim of this study was to evaluate the role of adherence to WCRF lifestyle recommendations in BE onset and progression. The secondary aim was to investigate the association between disease progression and specific aspects of diet and lifestyle. METHODS: Established risk factors for BE and EAC development and adherence to WCRF guidelines were assessed in 107 consecutive patients undergoing an upper gastrointestinal endoscopy for symptoms suggesting gastroesophageal reflux (GERD) and a suspected diagnosis of BE/dysplasia on BE. Patients were divided according to histology: those with GERD without metaplasia, with non-dysplastic BE, with low-grade dysplasia, with high-grade dysplasia or with early EAC. The four groups were expressed as an ordered categorical variable of disease progression. An ordered logit model was estimated to identify the independent predictors of disease progression. RESULTS: Adherence to WCRF guidelines was identified as independent protective factor (OR 0.51, 95 % CI 0.37-0.67) of disease progression. Disease progression was associated with reduced adherence to guidelines on physical activity (from 48.2 to 5.3 %, p = 0.001), sedentary habits (from 33.3 to 0 %, p = 0.03), fruit consumption (from 37.0 to 5.6 %, p = 0.02) and processed meat consumption (from 51.9 to 10.5 %, p = 0.002). CONCLUSION: Adherence to WCRF guidelines has a protective factor in BE onset and its evolution to EAC.

The role of flexible endotherapy for the treatment of recurrent Zenker's diverticula after surgery and endoscopic stapling.

BACKGROUND: Currently there are three main treatment options for Zenker's diverticulum (ZD): surgery, rigid endoscopy and flexible endoscopy. After primary success, recurrence can be as high as 19 % for surgery, 12.8 % for rigid endoscopy and 20 % for flexible endoscopy. Flexible endoscopy may represent an ideal treatment option for recurring ZD. The aims of this paper are to evaluate the efficacy and safety of flexible endotherapy for recurring ZD after surgery and/or endoscopic stapling and to compare the treatment outcome between naive and recurring patients. METHODS: Data on patients that underwent flexible endotherapy for ZD between January 2010 and January 2015 were collected. Patients were divided into those with recurrences after surgery and/or endoscopic stapling and those who did not have previous treatments. Dysphagia, regurgitation, and respiratory symptom severity before the procedure were graded. The outcome parameters were: complications, symptom improvement after the first treatment, number of treatment sessions, rate of complete remission and relapses. These parameters were then compared between patients groups. RESULTS: Twenty-five recurring patients were included. Treatment was carried out successfully in all patients. Two adverse events occurred; they were successfully managed conservatively. After the first treatment, there was a significant reduction in dysphagia, regurgitation and respiratory symptoms scores. The median number of treatments was 1 (IQR 0.25, range 1-3): symptom remission was achieved in 84 % patients and partial improvement in 16 %. Relapsing symptoms occurred in 20 % patients; they were successfully managed with an additional treatment session. Results were compared with data on 34 consecutive naive patients treated within the same time span; no differences of the outcome parameters were revealed. CONCLUSIONS: Flexible endotherapy for ZD recurrences after surgery and endoscopic stapling appears to be safe and effective, and its efficacy and safety profile seems to be comparable between recurring and naive patients.

Feasibility, efficacy and safety of stent insertion as a palliative treatment for malignant strictures in the cervical segment of the esophagus and the hypopharynx.

BACKGROUND: 50% of esophageal cancers are inoperable at the time of diagnosis, and around 15% involve the cervical esophagus. The hypopharynx is often involved by these malignancies as well. Palliation of cervical esophageal malignancies through stent insertion is considered limited due to technical challenges, poor patient tolerance and high complication rate. The aim of this study is to review our experience with stent insertion in the cervical segment of the esophagus and to evaluate outcome differences between stent insertions involving or sparing the hypopharynx. METHODS: We retrospectively reviewed data on 69 consecutive patients that underwent stent insertion for malignant strictures in the cervical esophagus at our Department. Patients were divided according to involvement or sparing of the lower hypopharynx. Dysphagia severity was measured with the Mellow-Pinkas scale before the procedure and on monthly follow-ups. Any complication and its management were recorded. The main outcome parameters were as follows: dysphagia improvement, rate of successful dysphagia palliation (i.e., a reduction of the score to 0 or 1 after stent insertion) and complication rate. Multivariable analysis was carried out to assess the influence of patient- and procedure-related factors on the outcome of the procedure. RESULTS: Stent insertion was achieved in 100% patients. At 4 weeks, dysphagia score improved from a median of 3-0 (p < 0.001), and a successful palliation was achieved in 76.8% patients. The 30-day mortality rate was 14.5%. Successful palliation throughout the follow-up was achieved in 72.9% of the surviving patients. Complications occurred in 31.9% patients. Dilation before stent insertion was associated with a less efficient short-term dysphagia palliation (OR 6.77, 95% CI 1.46-31.29, p = 0.02). CONCLUSIONS: Stent insertion is a safe and effective palliative treatment for malignant cervical esophageal strictures. Results are consistent even in patients with hypopharyngeal lesions. Dilation should be avoided before stent insertion.

Continuous neurodegeneration and death pathway activation in neurons and glia in an experimental model of severe chronic epilepsy.

Whether seizures might determine the activation of cell death pathways and what could be the relevance of seizure-induced cell death in epilepsy are still highly debated issues. We recently developed an experimental model of acquired focal cortical dysplasia (the MAM-pilocarpine or MP rat) in which the occurrence of status epilepticus--SE--and subsequent seizures induced progressive cellular/molecular abnormalities and neocortical/hippocampal atrophy. Here, we exploited the same model to verify when, where, and how cell death occurred in neurons and glia during epilepsy course. We analyzed Fluoro Jade (FJ) staining and the activation of c-Jun- and caspase-3-dependent pathways during epilepsy, from few hours post-SE up to six months of spontaneous recurrent seizures. FJ staining revealed that cell injury in MP rats was not temporally restricted to SE, but extended throughout the different epileptic stages. The region-specific pattern of FJ staining changed during epilepsy, and FJ(+) neurons became more prominent in the dorsal and ventral hippocampal CA at chronic epilepsy stages. Phospho-c-Jun- and caspase-3-dependent pathways were selectively activated respectively in neurons and glia, at early but even more conspicuously at late chronic stages. Phospho-c-Jun activation was associated with increased cytochrome-c staining, particularly at chronic stages, and the staining pattern of cytochrome-c was suggestive of its release from the mitochondria. Taken together, these data support the content that at least in the MP rat model the recurrence of seizures can also sustain cell death mechanisms, thus continuously contributing to the pathologic process triggered by the occurrence of SE.

Flexible endoscopic treatment for Zenker's diverticulum with the SB Knife. Preliminary results from a single-center experience.

BACKGROUND AND AIM: Flexible endoscopic septum division is becoming a prominent treatment option for Zenker's diverticulum (ZD). Over the years, various techniques have been developed and many cutting tools have been tested with varying results. We report our experience with a recently designed, monopolar, rotating, scissor-shaped device (SB Knife). METHODS: Data on 31 consecutive patients that underwent flexible endoscopic treatment for ZD with the use of the SB Knife were retrieved. Dysphagia, regurgitation, and respiratory symptom severity before the procedure were graded. Procedure duration, rate of complications, symptom changes after the procedure and rate of relapsing patients during follow up were recorded. RESULTS: The procedure was carried out successfully in all patients. Median procedure time was 14 min. One case of late-onset bleeding developed 1 week after the procedure, and was managed endoscopically. A significant symptom improvement was achieved (dysphagia: median score <3, median score >0, P < 0.001; regurgitation: median score <2, median score >0, P < 0.001; respiratory symptoms: median score <2, median score >0, P = 0.009). Two patients had mild relapsing symptoms, respectively, after 4 and 9 months from the procedure but refused further treatment. CONCLUSIONS: Endoscopic treatment of ZD using this new device is safe and efficient at short term follow up. No perforations were observed and there was a substantial reduction of symptoms after the treatment. Larger studies are needed to fully assess advantages of this new device for endoscopic treatment of ZD.

Human axonal survival of motor neuron (a-SMN) protein stimulates axon growth, cell motility, C-C motif ligand 2 (CCL2), and insulin-like growth factor-1 (IGF1) production.

Spinal muscular atrophy is a fatal genetic disease of motoneurons due to loss of full-length survival of motor neuron protein, the main product of the disease gene SMN1. Axonal SMN (a-SMN) is an alternatively spliced isoform of SMN1, generated by retention of intron 3. To study a-SMN function, we generated cellular clones for the expression of the protein in mouse motoneuron-like NSC34 cells. The model was instrumental in providing evidence that a-SMN decreases cell growth and plays an important role in the processes of axon growth and cellular motility. In our conditions, low levels of a-SMN expression were sufficient to trigger the observed biological effects, which were not modified by further increasing the amounts of the expressed protein. Differential transcriptome analysis led to the identification of novel a-SMN-regulated factors, i.e. the transcripts coding for the two chemokines, C-C motif ligands 2 and 7 (CCL2 and CCL7), as well as the neuronal and myotrophic factor, insulin-like growth factor-1 (IGF1). a-SMN-dependent induction of CCL2 and IGF1 mRNAs resulted in increased intracellular levels and secretion of the respective protein products. Induction of CCL2 contributes to the a-SMN effects, mediating part of the action on axon growth and random cell motility, as indicated by chemokine knockdown and re-addition studies. Our results shed new light on a-SMN function and the underlying molecular mechanisms. The data provide a rational framework to understand the role of a-SMN deficiency in the etiopathogenesis of spinal muscular atrophy.

Long-duration epilepsy affects cell morphology and glutamatergic synapses in type IIB focal cortical dysplasia.

To investigate hypothesized effects of severe epilepsy on malformed cortex, we analyzed surgical samples from eight patients with type IIB focal cortical dysplasia (FCD) in comparison with samples from nine non-dysplastic controls. We investigated, using stereological quantification methods, where appropriate, dysplastic neurons, neuronal density, balloon cells, glia, glutamatergic synaptic input, and the expression of N-methyl-D-aspartate (NMDA) receptor subunits and associated membrane-associated guanylate kinase (MAGUK). In all FCD patients, the dysplastic areas giving rise to epileptic discharges were characterized by larger dysmorphic neurons, reduced neuronal density, and increased glutamatergic inputs, compared to adjacent areas with normal cytology. The duration of epilepsy was found to correlate directly (a) with dysmorphic neuron size, (b) reduced neuronal cell density, and (c) extent of reactive gliosis in epileptogenic/dysplastic areas. Consistent with increased glutamatergic input, western blot revealed that NMDA regulatory subunits and related MAGUK proteins were up-regulated in epileptogenic/dysplastic areas of all FCD patients examined. Taken together, these results support the hypothesis that epilepsy itself alters morphology-and probably also function-in the malformed epileptic brain. They also suggest that glutamate/NMDA/MAGUK dysregulation might be the intracellular trigger that modifies brain morphology and induces cell death.

Intrinsic epileptogenicity of dysplastic cortex: converging data from experimental models and human patients.

Focal cortical dysplasia (FCD) is a brain malformation associated with particularly severe drug-resistant epilepsy that often requires surgery for seizure control. The molecular basis for such enhanced propensity to seizure generation in FCD is not as yet elucidated. To investigate cellular and molecular bases of epileptogenic mechanisms and possible effect of severe epilepsy on the malformed cortex we have here performed a parallel analysis of a rat model of acquired cortical dysplasia previously established in our laboratory, i.e., the methylazoxymethanol/pilocarpine (MAM-PILO) rats, and surgical samples from patients with type IIB FCD. Data from the MAM-PILO rat model and human FCD samples reveal in both conditions: (1) that status epilepticus (SE) and/or seizures can further modify the cellular and molecular settings of the malformed cortex; (2) excitation/inhibition imbalance, and dysregulation of the N-methyl-d-aspartate/ membrane-associated guanylate kinase (NMDA/MAGUK) expression; (3) activation of cell death in neurons and glia. The data therefore highlight the mechanistic relevance of glutamate/NMDA hyperactivation in FCD epileptogenesis and suggest that epilepsy is a pathologic process capable of affecting structure and function of both neurons and glia.

Spinal muscular atrophy pathogenic mutations impair the axonogenic properties of axonal-survival of motor neuron.

The axonal survival of motor neuron (a-SMN) protein is a truncated isoform of SMN1, the spinal muscular atrophy (SMA) disease gene. a-SMN is selectively localized in axons and endowed with remarkable axonogenic properties. At present, the role of a-SMN in SMA is unknown. As a first step to verify a link between a-SMN and SMA, we investigated by means of over-expression experiments in neuroblastoma-spinal cord hybrid cell line (NSC34) whether SMA pathogenic mutations located in the N-terminal part of the protein affected a-SMN function. We demonstrated here that either SMN1 missense mutations or small intragenic re-arrangements located in the Tudor domain consistently altered the a-SMN capability of inducing axonal elongation in vitro. Mutated human a-SMN proteins determined in almost all NSC34 motor neurons the growth of short axons with prominent morphologic abnormalities. Our data indicate that the Tudor domain is critical in dictating a-SMN function possibly because it is an association domain for proteins involved in axon growth. They also indicate that Tudor domain mutations are functionally relevant not only for FL-SMN but also for a-SMN, raising the possibility that also a-SMN loss of function may contribute to the pathogenic steps leading to SMA.

Barrett's esophagus and adenocarcinoma risk: the experience of the North-Eastern Italian Registry (EBRA).

OBJECTIVE: To establish the incidence and risk factors for progression to high-grade intraepithelial neoplasia (HG-IEN) or Barrett's esophageal adenocarcinoma (BAc) in a prospective cohort of patients with esophageal intestinal metaplasia [(BE)]. BACKGROUND: BE is associated with an increased risk of BAc unless cases are detected early by surveillance. No consistent data are available on the prevalence of BE-related cancer, the ideal surveillance schedule, or the risk factors for cancer. METHODS: In 2003, a regional registry of BE patients was created in north-east Italy, establishing the related diagnostic criteria (endoscopic landmarks, biopsy protocol, histological classification) and timing of follow-up (tailored to histology) and recording patient outcomes. Thirteen centers were involved and audited yearly. The probability of progression to HG-IEN/BAc was calculated using the Kaplan-Meier method; the Cox regression model was used to calculate the risk of progression. RESULTS: HG-IEN (10 cases) and EAc (7 cases) detected at the index endoscopy or in the first year of follow-up were considered to be cases of preexisting disease and excluded; 841 patients with at least 2 endoscopies {median, 3 [interquartile range (IQR): 2-4); median follow-up = 44.6 [IQR: 24.7-60.5] months; total 3083 patient-years} formed the study group [male/female = 646/195; median age, 60 (IQR: 51-68) years]. Twenty-two patients progressed to HG-IEN or BAc (incidence: 0.72 per 100 patient-years) after a median of 40.2 (26.9-50.4) months. At multivariate analysis, endoscopic abnormalities, that is, ulceration or nodularity (P = 0.0002; relative risk [RR] = 7.6; 95% confidence interval, 2.63-21.9), LG-IEN (P = 0.02, RR = 3.7; 95% confidence interval, 1.22-11.43), and BE length (P = 0.01; RR = 1.16; 95% confidence interval, 1.03-1.30) were associated with BE progression. Among the LG-IEN patients, the incidence of HG-IEN/EAc was 3.17 patient-years, that is, 6 times higher than in BE patients without LG-IEN. CONCLUSIONS: These results suggest that in the absence of intraepithelial neoplastic changes, BE carries a low risk of progression to HG-IEN/BAc, and strict surveillance (or ablative therapy) is advisable in cases with endoscopic abnormalities, LG-IEN or long BE segments.

Early HER2 dysregulation in gastric and oesophageal carcinogenesis.

AIMS: To explore human epidermal growth factor receptor 2 (HER2) status in the histological phenotypes [metaplasia, intraepithelial neoplasia (IEN, i.e. dysplasia), and adenocarcinoma] involved in the morphogenesis of both intestinal-type gastric cancer (GC) and Barrett's adenocarcinoma (BAc). METHODS AND RESULTS: A consecutive series of 275 samples of stomach and oesophagus tissue (representing the whole spectrum of the phenotypic changes involved in gastric and Barrett's carcinogenesis) was studied. HER2 status was assessed by applying two immunohistochemistry (IHC) protocols, using the antibodies 4B5 and CB11. Dual-colour silver chromogenic in-situ hybridization (SISH) was also performed on the same tissue samples. In both oesophageal and gastric samples, the rate of HER2 overexpression rose significantly from low-grade to high-grade IEN to adenocarcinoma (P < 0.001), with the two IHC protocols showing consistent staining (consistency 95%; k = 0.78; P < 0.001). Intratumour heterogeneity was documented in both GC and BAc (using both IHC protocols). The rate of HER2 amplification (using SISH) increased significantly along with IEN dedifferentiation (P < 0.001). Neither native nor metaplastic mucosa samples (obtained from either stomach or oesophagus) ever showed HER2 amplification. There was excellent agreement between HER2 amplification and protein overexpression (both IHC protocols: SISH/4B5--consistency 97.8%, k = 0.89, P < 0.001; SISH/CB11-consistency 97.8%, k = 0.91, P < 0.001). CONCLUSIONS: There is early involvement of HER2 dysregulation (amplification and protein overexpression) in both gastric (intestinal-type) and Barrett's oncogenesis.

Status epilepticus-induced pathologic plasticity in a rat model of focal cortical dysplasia.

We have generated an experimental 'double-hit' model of chronic epilepsy to recapitulate the co-existence of abnormal cortical structure and frequently recurrent seizures as observed in human focal cortical dysplasia. We induced cortical malformations by exposing rats prenatally to methylazoxymethanol acetate and triggered status epilepticus and recurrent seizures in adult methylazoxymethanol acetate rats with pilocarpine. We studied the course of epilepsy and the long-term morphologic and molecular changes induced by the occurrence of status epilepticus and subsequent chronic epilepsy in the malformed methylazoxymethanol acetate exposed brain. Behavioural and electroencephalographic analyses showed that methylazoxymethanol acetate pilocarpine rats develop more severe epilepsy than naïve rats. Morphologic and molecular analyses demonstrated that status epilepticus and subsequent seizures, but not pilocarpine treatment per se, was capable of affecting both cortical architectural and N-methyl-D-aspartate receptor abnormalities induced by methylazoxymethanol acetate. In particular, cortical thickness was further decreased and N-methyl-D-aspartate regulatory subunits were recruited at the postsynaptic membrane. In addition, methylazoxymethanol acetate pilocarpine rats showed abnormally large cortical pyramidal neurons with neurofilament over-expression. These neurons bear similarities to the hypertrophic/dysmorphic pyramidal neurons observed in acquired human focal cortical dysplasia. These data show that status epilepticus sets in motion a pathological process capable of significantly changing the cellular and molecular features of pre-existing experimental cortical malformations. They suggest that seizure recurrence in human focal cortical dysplasia might be an additional factor in establishing a pathological circuitry that favours chronic neuronal hyperexcitability.

Comparison of preoperative and surgical measurements of Zenker's diverticulum.

BACKGROUND: Zenker's diverticulum (ZD) may be treated with a variety of endoscopic or open surgical techniques; the choice of treatment depends partly on the size of the diverticulum. The purpose of this study was to correlate ZD measurements obtained preoperatively and during surgery. METHODS: From March 2006 to November 2008, 20 consecutive patients (19 males; median age 64.5 (range 37-88) years) with dysphagia secondary to ZD were enrolled for this study. All patients had preoperative barium radiography of the pharynx and esophagus, and diagnostic endoscopy. Ten patients underwent transoral stapling diverticulostomy and ten had open surgery. The depth of the ZD was measured on radiographic views, at endoscopy and during surgery, focusing on the distance from the top of the septum to the bottom of the pouch. The ZD dimensions obtained radiologically and endoscopically were compared with those found during surgery. Correlations and agreements between measurements were assessed using Pearson's correlation coefficients and method-comparison analysis, respectively. RESULTS: The median depth of the ZD was 2.9 cm (mean 2.95 ± 1.12 cm; range 1.5-6 cm), 3.0 cm (mean 3.24 ± 1.27 cm; range 1.7-6.8 cm), and 3.0 cm (mean 2.99 ± 1.01 cm; range 1.5-6 cm) when measured during surgery, radiology, and endoscopy, respectively. The correlation and agreement between the radiographic and surgical ZD measurements were good, whereas those between the endoscopic and surgical measurements were poor. CONCLUSIONS: These findings confirm that preoperative barium radiography is mandatory in order to choose the most appropriate surgical treatment for ZD.

[Microbubbles: current state and future prospects]. / Le microbolle: attualita' e prospettive future.

Contrast-enhanced ultrasound (CEUS) represents one of the most interesting applications of traditional medical sonography. Ultrasound contrast agents are classified into first- and second-generation agents depending on the gas (nitrogen, perfluorocarbon or sulfur hexafluoride) in the microbubbles. Both generations are characterized by an excellent safety profile, with low hepatic and renal toxicity and rare central nervous system reactions. The respiratory and hepatic elimination of the gases explains the low nephrotoxicity. CEUS has been successfully employed in drug and gene delivery. Indeed, new molecules such as liposomes, micelles and perfluorocarbon nanoparticles have been recently proposed as ultrasound contrast agents. Possible future applications of liposomes are the treatment of hypertension complications (given the possibility to fill them with nitric oxide), the treatment of cerebral disease with xenon, and the treatment of breast and liver cancer with doxorubicin. Micelles have been demonstrated to be effective in cancer treatment as well. Finally, perfluorocarbon nanoparticles can be used in oncological settings and in pancreatic islet transplantation in patients with type I diabetes.

Misplaced NMDA receptors in epileptogenesis contribute to excitotoxicity.

Pharmacological blockade of NR2B-containing N-methyl-d-aspartate receptors (NMDARs) during epileptogenesis reduces neurodegeneration provoked in the rodent hippocampus by status epilepticus. The functional consequences of NMDAR activation are crucially influenced by their synaptic vs extrasynaptic localization, and both NMDAR function and localization are dependent on the presence of the NR2B subunit and its phosphorylation state. We investigated whether changes in NR2B subunit phosphorylation, and alterations in its neuronal membrane localization and cellular expression occur during epileptogenesis, and if these changes are involved in neuronal cell loss. We also explored NR2B subunit changes both in the acute phase of status epilepticus and in the chronic phase of spontaneous seizures which encompass the epileptogenesis phase. Levels of Tyr1472 phosphorylated NR2B subunit decreased in the post-synaptic membranes from rat hippocampus during epileptogenesis induced by electrical status epilepticus. This effect was concomitant with a reduced interaction between NR2B and post-synaptic density (PSD)-95 protein, and was associated with decreased CREB phosphorylation. This evidence suggests an extra-synaptic localization of NR2B subunit in epileptogenesis. Accordingly, electron microscopy showed increased NR2B both in extra-synaptic and pre-synaptic neuronal compartments, and a concomitant decrease of this subunit in PSD, thus indicating a shift in NR2B membrane localization. De novo expression of NR2B in activated astrocytes was also found in epileptogenesis indicating ectopic receptor expression in glia. The NR2B phosphorylation changes detected at completion of status epilepticus, and interictally in the chronic phase of spontaneous seizures, are predictive of receptor translocation from synaptic to extrasynaptic sites. Pharmacological blockade of NR2B-containing NMDARs by ifenprodil administration during epileptogenesis significantly reduced pyramidal cell loss in the hippocampus, showing that the observed post-translational and cellular changes of NR2B subunit contribute to excitotoxicity. Therefore, pharmacological targeting of misplaced NR2B-containing NMDARs, or prevention of these NMDAR changes, should be considered to block excitotoxicity which develops after various pro-epileptogenic brain injuries.