The Impact of Oxygen on Bacterial Enteric Pathogens.

Bacterial enteric pathogens are responsible for a tremendous amount of foodborne illnesses every year through the consumption of contaminated food products. During their transit from contaminated food sources to the host gastrointestinal tract, these pathogens are exposed and must adapt to fluctuating oxygen levels to successfully colonize the host and cause diseases. However, the majority of enteric infection research has been conducted under aerobic conditions. To raise awareness of the importance in understanding the impact of oxygen, or lack of oxygen, on enteric pathogenesis, we describe in this review the metabolic and physiological responses of nine bacterial enteric pathogens exposed to environments with different oxygen levels. We further discuss the effects of oxygen levels on virulence regulation to establish potential connections between metabolic adaptations and bacterial pathogenesis. While not providing an exhaustive list of all bacterial pathogens, we highlight key differences and similarities among nine facultative anaerobic and microaerobic pathogens in this review to argue for a more in-depth understanding of the diverse impact oxygen levels have on enteric pathogenesis.

Formula feeding and systemic hypoxia synergistically induce intestinal hypoxia in experimental necrotizing enterocolitis.

PURPOSE: Feeding and systemic hypoxia are major stresses inducing necrotizing enterocolitis (NEC). This study aims to investigate the role of systemic hypoxia in NEC and its effect before and after feeding. METHODS: Neonatal mice were studied in three groups. Control (N = 9): breast feeding; NEC A (N = 8), gavage feeding + lipopolysaccharide (LPS) + preprandial hypoxia; and NEC B (N = 9), feeding + LPS + postprandial hypoxia. Pimonidazole, a hypoxia marker, was injected intraperitoneally before ileum was harvested for histology and quantitative RT-PCR studies. Statistical analysis was done using the ANOVA and Chi-square test. RESULTS: NEC incidence was 62.5% in NEC A and 88.9% in NEC B. The mortality in NEC B (55.6%) but not A (25%) is significantly higher than control (0%, p < 0.05). Pimonidazole staining elevated in both NEC A and B with higher pimonidazole grade in NEC B (p < 0.01). Both NEC groups had increased the expression of hypoxia-related genes: HIF-1α, GLUT-1, and PHD-3 with GLUT-1 expressed more in NEC B compared with NEC A (p < 0.01). The inflammation marker, IL6, was similarly raised in both NEC A and B. CONCLUSION: Feeding and postprandial hypoxia synergistically induce intestinal hypoxia in NEC. As feeding increases intestinal oxygen demand, maintaining a balance between intestinal oxygen supply and demand is important to prevent NEC.

Is single incision pediatric endoscopic surgery more painful than standard laparoscopy in children? Personal experience and review of the literature.

AIM: It has been speculated that single incision pediatric endoscopic surgery (SIPES) in children could result in more postoperative pain given the device size for a child umbilicus. Herein, we compare the postoperative pain in children who underwent SIPES or standard laparoscopy (SL). METHODS: Patients who underwent SIPES via Olympus TriPort™ Access system between 2010 and 2011 were prospectively compared with SL controls (similar age, sex and type of operation). Primary endpoint was analgesic requirement (number of doses and dose/kg). A systematic review of the literature included all articles (2008-2012) comparing postoperative pain following transumbilical SIPES and SL in children. Data were analyzed using non-parametric tests. RESULTS: Ten patients (8 males, median age 9 years, range 4-15) underwent 11 SIPES procedures: appendicectomy (N.=6), orchidopexy (N.=2), cholecystectomy (N.=2), and total colectomy (N.=1). There was no difference in paracetamol requirement between SIPES (median 74 mg/kg, range 14-149) and SL (median 59 mg/kg, range 13-108, P=0.76) patients. Morphine was required by only two patients per group (no difference in dosage or frequency). Eight studies (2010-2012) comparing 334 SIPES vs. 343 SL patients were analysed. Three studies showed advantage of SIPES, and four no difference between SIPES and SL. One randomized trial reported greater pain in SIPES appendicectomy, but no difference with SL once patients were discharged home. CONCLUSION: SIPES does not seem to be associated with more postoperative pain than SL in children. In appropriate cases, SIPES is a valid alternative to SL for a good range of pediatric procedures.

Antegrade continence enema (ACE): predictors of outcome in 111 patients.

PURPOSE: The antegrade continence enema (ACE) is used as a means of managing faecal incontinence and constipation with varying outcomes. We aim to evaluate our outcomes of ACEs and identify predictors of outcome. METHODS: A retrospective case-note review of patients ≤16 years of age undergoing an ACE (March 2000-September 2013) was carried out. Data collected included: patient demographics, functional outcomes and complications. Data are quoted as median (range) and compared using Mann-Whitney and Fisher's exact test. Univariate analysis was performed to identify predictors of successful outcomes. P < 0.05 is significant. Successful outcome = total continence/occasional leakage and failed outcome = regular soiling and/or constipation. RESULTS: 111 patients with complete data sets underwent an ACE [59% male, median age = 9.5 years (3.4-16 years)] and median follow-up = 48 months (4 months-11 years 4 months). Underlying diagnoses were idiopathic constipation (n = 68), anorectal malformation (n = 27), neuropathic bowel (n = 7), Hirschsprung disease (n = 5) and gastrointestinal dysmotility (n = 4). Social continence was achieved in 87/111 (78%). Fifteen percent of patients underwent reversal of ACE due to resolution of symptoms. There was no difference in outcomes related to diagnosis, gender, age or follow-up duration. Complication rate was 20.7% (23/111). CONCLUSIONS: The ACE is safe and effective in the management of intractable constipation and soiling. No predictors of outcome were identified.

The colorectal cancer screening program in the local health unit n. 6 of Livorno: evaluation of the screening activity in the period 2000-2011.

INTRODUCTION: The colorectal cancer screening program in the Local Health Unit n. 6 of Livorno is running since July 2000 and is meant to residents, aged between 50 and 70, who are invited to perform the test for faecal occult blood every 2 years. The aim of this work is an evaluation of the screening activity in the period 2000-2011. METHODS: The evaluation is based on the analysis of the main quality indicators formulated by GISCoR (Italian Group for Colorectal screening). RESULTS: The screening activity extension reached 93% in 2006 and 100% in 2009. The compliance level was maintained above the acceptable GISCoR value (> 45%) with a maximum of 54.9%. Values around 80% were recorded for the compliance to colonoscopy. The detection rate (DR) for cancer and advanced adenoma showed, as expected, the highest values in the early years and then move on values consistently lower than the regional average. In 2011, the raw DR for cancer was 0.9 x 1000 and the raw DR for advanced adenoma 5.3 x 1000. The distribution by stage at diagnosis of screen-detected carcinomas shows that 58.1% of these were identified at stage I while the proportion of cases in stage III+ is 19.5%. CONCLUSIONS: The overall analysis shows a good performance of the program. The proportion of colonoscopies performed on the total number of positive subjects remains a critical point of the system. The distribution by stage of screen-detected cancers shows an excellent diagnostic anticipation of the screening program.

Acute hypoxia alters visuospatial attention orienting: an electrical neuroimaging study.

Our study investigated the effects of hypoxia on visuospatial attention processing during preparation for a single/double-choice motor response. ERPs were recorded in two sessions in which participants breathed either ambient-air or oxygen-impoverished air. During each session, participants performed four cue-target attention orienting and/or alerting tasks. Replicating the classic findings of valid visuospatial attentional orienting modulation, ERPs to pre-target cues elicited both an Anterior directing attention negativity (ADAN)/CNV and a posterior Late directing attention positivity (LDAP)/TP, which in ambient air were larger for attention orienting than for alerting. Hypoxia increased the amplitude of both these potentials in the spatial orienting conditions for the upper visual hemifield, while, for the lower hemifield, it increased ADAN/CNV, but decreased LDAP/TP for the same attention conditions. To these ERP changes corresponded compensatory enhanced activation of right anterior cingulate cortex, left superior parietal lobule and frontal gyrus, as well as detrimental effects of hypoxia on behavioral overt performance. Together, these findings reveal for the first time, to our knowledge, that (1) these reversed alterations of the activation patterns during the time between cue and target occur at a larger extent in hypoxia than in air, and (2) acute normobaric hypoxia alters visuospatial attention orienting shifting in space.

The predictive value of clinical, radiographic, echocardiographic variables and cardiac biomarkers for assessing risk of the onset of heart failure or cardiac death in dogs with preclinical myxomatous mitral valve disease enrolled in the DELAY study.

OBJECTIVES: To identify the predictive value on time to onset of heart failure (HF) or cardiac death of clinical, radiographic, and echocardiographic variables, as well as cardiac biomarkers N-terminal pro brain natriuretic peptide (NT-proBNP) and cardiac troponin I in dogs with preclinical myxomatous mitral valve disease (MMVD). ANIMALS: One hundred sixty-eight dogs with preclinical MMVD and left atrium to aortic root ratio ≥1.6 (LA:Ao) and normalized left ventricular end-diastolic diameter ≥1.7 were included. METHODS: Prospective, randomized, multicenter, single-blinded, placebo-controlled study. Clinical, radiographic, echocardiographic variables and plasma cardiac biomarkers concentrations were compared at different time points. Using receiving operating curves analysis, best cutoff for selected variables was identified and the risk to develop the study endpoint at six-month intervals was calculated. RESULTS: Left atrial to aortic root ratio >2.1 (hazard ratio [HR] 3.2, 95% confidence interval [95% CI] 1.9-5.6), normalized left ventricular end-diastolic diameter > 1.9 (HR: 6.3; 95% CI: 3.3-11.8), early transmitral peak velocity (E peak) > 1 m/sec (HR: 3.9; 95% CI: 2.3-6.7), and NT-proBNP > 1500 ρmol/L (HR: 5.7; 95% CI: 3.3-9.5) were associated with increased risk of HF or cardiac death. The best fit model to predict the risk to reach the endpoint was represented by the plasma NT-proBNP concentrations adjusted for LA:Ao and E peak. CONCLUSIONS: Logistic and survival models including echocardiographic variables and NT-proBNP can be used to identify dogs with preclinical MMVD at higher risk to develop HF or cardiac death.

DELay of Appearance of sYmptoms of Canine Degenerative Mitral Valve Disease Treated with Spironolactone and Benazepril: the DELAY Study.

INTRODUCTION: Efficacy of renin-angiotensin-aldosterone system (RAAS) blockade using angiotensin-converting enzyme inhibitors (ACEi) in dogs with preclinical myxomatous mitral valve disease (MMVD) is controversial. HYPOTHESIS: Administration of spironolactone (2-4 mg q 24 h) and benazepril (0.25-0.5 mg q 24 h) in dogs with preclinical MMVD, not receiving any other cardiac medications, delays the onset of heart failure (HF) and cardiac-related death. Moreover, it reduces the progression of the disease as indicated by echocardiographic parameters and level of cardiac biomarkers N-terminal pro brain natriuretic peptide (NT-proBNP) and cardiac troponin I (cTnI). ANIMALS: 184 dogs with pre-clinical MMVD and left atrium-to-aortic root ratio (LA:Ao) ≥1.6 and normalized left ventricular end-diastolic diameter (LVEDDn) ≥1.7. METHODS: This is a prospective, randomized, multicenter, single-blinded, placebo-controlled study. Primary outcome variable was time-to-onset of first occurrence of HF or cardiac death. Secondary end points included effect of treatment on progression of the disease based on echocardiographic and radiographic parameters, as well as variations of NT-proBNP and cTnI concentrations. RESULTS: The median time to primary end point was 902 days (95% confidence interval (CI) 682-not available) for the treatment group and 1139 days (95% CI 732-NA) for the control group (p = 0.45). Vertebral heart score (p = 0.05), LA:Ao (p < 0.001), LVEDDn (p < 0.001), trans-mitral E peak velocity (p = 0.011), and NT-proBNP (p = 0.037) were lower at the end of study in the treatment group. CONCLUSIONS: This study failed in demonstrating that combined administration of spironolactone and benazepril delays onset of HF in dogs with preclinical MMVD. However, such treatment induces beneficial effects on cardiac remodeling and these results could be of clinical relevance.

Assessment of a neonatal rat model of necrotizing enterocolitis.

INTRODUCTION: A neonatal rat model of necrotizing enterocolitis (NEC) is useful to investigate this devastating and obscure disease. The aim of this study was to assess a neonatal rat model of NEC to evaluate whether the histological appearance of the damaged intestine could be predicted by the clinical behaviour of the animals and the macroscopic appearance of the gut. MATERIALS AND METHODS: Neonatal rats were delivered at term and assigned either to a control group consisting of breastfeeding and no stress factors, or to a NEC group in which NEC was induced by gavage feeding + hypoxia + oral lipopolysaccharide (4 mg/kg/day once daily for the first 2 days of life). Clinical status was assessed on day 4 using a clinical sickness score (general appearance, response to touch, natural activity, body colour; 0 - 3 for each variable). Neonatal rats were sacrificed at 4 different time points: day 1, day 2, day 3, and day 4. At sacrifice, a macroscopic assessment of the gut was performed using a new scoring system based on: colour (0 - 2), consistency (0 - 2) and degree of dilatation (0 - 2). The resected gut was stained with haematoxylin/eosin, and evaluated microscopically by 2 independent blinded scorers, including a consultant histopathologist. The histology results were used to validate the macroscopic gut assessment. Results were compared by ANOVA and linear regression analysis. Ethics Committee and Home Office approvals were obtained. RESULTS: In the control group NEC was not present either macroscopically or histologically. The clinical sickness score was higher in the NEC group (median = 4.5; range = 2 - 6) compared to controls (median = 0; range = 0 - 1; p < 0.0001). In the NEC group the macroscopic appearance (from day 2) and histological score (from day 1) increased significantly (p < 0.0001) and were strongly correlated (r (2) = 0.74, p < 0.0001). CONCLUSIONS: The clinical behaviour and macroscopic appearance of the intestine are valid tools to assess gut damage in our neonatal rat model of NEC. This allows future studies that are not exclusively based on histology.

Delta9-tetrahydrocannabinol (THC) and AM 404 protect against cerebral ischaemia in gerbils through a mechanism involving cannabinoid and opioid receptors.

BACKGROUND AND PURPOSE: It has been suggested that the endocannabinoid system elicits neuroprotection against excitotoxic brain damage. In the present study the therapeutic potential of AM 404 on ischaemia-induced neuronal injury was investigated in vivo and compared with that of the classical cannabinoid receptor type 1 (CB1) agonist, delta 9-tetraydrocannabinol (THC), using a model of transient global cerebral ischaemia in the gerbil. EXPERIMENTAL APPROACH: The effects of AM 404 (0.015-2 mg kg(-1)) and THC (0.05-2 mg kg(-1)), given 5 min after ischaemia, were measured from 1 h to 7 days in terms of electroencephalographic (EEG) total spectral power, spontaneous motor activity, memory function, rectal temperature and hippocampal CA1 neuronal count. KEY RESULTS: Over the dose range tested, AM 404 (2 mg kg(-1)) and THC (1 mg kg(-1)) completely reversed the ischaemia-induced behavioural, EEG and histological damage. Only THC (1 and 2 mg kg(-1)) induced a decrease of body temperature. Pretreatment with the selective CB1 receptor antagonist, AM 251 (1 mg kg(-1)) and the opioid antagonist, naloxone (2 mg kg(-1)) reversed the protective effect induced by both AM 404 and THC while the TRPV1 vanilloid antagonist, capsazepine (0.01 mg kg(-1)), was ineffective. CONCLUSIONS AND IMPLICATIONS: Our findings demonstrate that AM 404 and THC reduce neuronal damage caused by bilateral carotid occlusion in gerbils and that this protection is mediated through an interaction with CB1 and opioid receptors. Endocannabinoids might form the basis for the development of new neuroprotective drugs useful for the treatment of stroke and other neurodegenerative pathologies.

Compensatory renal growth in children with unilateral renal tumor treated by nephron-sparing surgery or nephrectomy.

INTRODUCTION: In children with an unilateral renal tumor, nephron-sparing surgery (NSS) results in a more adequate renal function adaptation compared to nephrectomy. In the present study, we investigated whether nephron-sparing surgery is followed by a different renal structure adaptation compared to nephrectomy. METHODS: Sixteen patients with unilateral renal tumor treated by nephrectomy (Group 1) and 10 treated by nephron-sparing surgery (Group 2) were enrolled in the study. Kidney volume was estimated by ultrasonography, using the formula for a prolate ellipsoid. Kidney volume was adjusted to the patient's weight and kidney laterality and expressed as a percentage of the expected volume of two kidneys in a healthy child. Total kidney volume (TKV) corresponded to the volume of the contralateral kidney in Group 1 patients, and to the volume of contralateral kidney + kidney remnant in Group 2 patients. Renal function was evaluated by serum creatinine values adjusted for sex and age and expressed as standard deviation scores (SDS). RESULTS: Group 2 patients presented with a greater indexed TKV compared to Group 1 patients, (97.4 +/- 18.8 % vs. 77.0 +/- 17.7 %; p = 0.005). Indexed TKV below the reference range for healthy controls with two kidneys was found in 4 of 10 Group 2 patients vs. 14 of 16 Group 1 patients (p = 0.017). In both patient groups, correlation analysis of indexed TKV and creatinine SDS showed a negative correlation (r = - 0.47; p = 0.01). CONCLUSION: In children with unilateral renal tumor, NSS is followed by a more adequate compensatory restoration of TKV compared with nephrectomy.

Oromandibular reconstruction using titanium plate and pectoralis major myocutaneous flap.

To assess whether locking-screw titanium plates (UniLOCK) and pedicled pectoralis major myocutaneous flaps are a valid alternative to complex reconstruction with bony free flaps in poor prognosis or poor performance status oncological patients with mandibular defects, a retrospective evaluation has been made of outcomes in 27 consecutive cases. No patient died perioperatively. Mean operating time was 270 minutes. Post-operative course was uneventful in 14. Mean follow-up was 13 months with no loss to follow-up. Twelve patients are alive and well, 12 died from their malignancy, two from non-neoplastic causes, and one from second cancer. Plate exposure - the main problem with bridging plates - occurred in 6 (22%, 4 early, 2 late), 4 with symphyseal and 2 with postero-lateral defects: removal was necessary in 2; 2 died with the plate exposed, and 2 had successful re-coverage, increasing the final success rate from 78% to 85%. Most patients considered the aesthetic outcome acceptable, however all edentulous patients complained of unsatisfactory dental rehabilitation. From the acceptable success rate, it may be concluded that bridging plates represent a useful reconstruction method, provided they are well covered by viable muscular tissue. They should be offered to patients contraindicated for more invasive procedures or with limited functional needs, or poor prognosis.

Pathogenesis of apparent life-threatening events in infants with esophageal atresia.

Many infants with a repaired esophageal atresia (EA) undergo fundoplication, aortopexy, or glossopexy because the mechanisms most responsible for airway obstruction and/or apparent life-threatening event (AO/ALTE) syndrome are considered to be gastroesophageal reflux (GER), tracheal compression (TC), or obstructive apnea, respectively. In the present study, we investigated whether these mechanisms are independent or interrelated. We developed a database of 120 consecutive patients with EA treated by the senior author between 1967-2002. We studied the clinical manifestations of patients with a cervical esophagostomy and/or blind lower esophageal stump, which ruled out TC and/or proximal esophageal GER as a mechanism for AO/ALTE. Of 25 neonates who underwent section/ligation of lower tracheo-esophageal fistula and/or feeding gastrostomy, 10 critically ill neonates died. Of 15 survivors, 9 infants had a feeding gastrostomy without an esophagostomy. Of these, 6 infants presented one or more episodes of AO, and 8 presented ALTE with or without AO. Subsequently, 5 of the 9 infants underwent an esophagostomy. Eventually, 11 infants had a feeding gastrostomy with an esophagostomy. Of the latter, 5 infants presented one or more episodes of AO, and 6 presented ALTE without AO. In conclusion, oral feeding, proximal esophageal GER, and TC are not essential for AO/ALTE syndrome to occur. They are probably factors which offer evidence of an underlying problem with control of upper airway patency.

Nutritional surveillance in Tuscany: eating habits at breakfast, mid-morning and afternoon snacks among 8-9 y-old children.

INTRODUCTION: The prevalence of overweight and obesity in children is rapidly increasing in many countries. For that it has been interesting to investigate the eating habits of 8-9 y-old Tuscany children by paying attention to their meals frequency per day and their food choices in total and in relation to children's Body Mass Index (BMI) classes. In addition we considered some environment factors that could affect the children eating behaviours, such as mother's BMI and their education level. METHODS: A statistical sample of 3076 (1583 males, 1493 females), 8-9 year-old school-children was collected; weight and height were measured using standardized personnel and instruments. BMI classes were calculated using Cole et al.'s cutoff for children and adolescents. In order to evaluate the consumption frequency of individual meals and various foods, a Food Frequency Questionnaire (FFQ) was used, which was completed by the children themselves at school. A self-administered questionnaire revealed the weight and height of parents and their educational levels. Three educational levels were established: high, medium and low. RESULTS: The results showed that 92.3% of children ate breakfast from 4-7 times a week, the vast majority at home, while only 3% declared consuming breakfast never or almost never The most preferred breakfast consisted of milk and biscuits for all children's BMI classes. 95.9% of children reported having midmorning snack at school; fruit juice and tea are the most frequently consumed liquid foods, and pizza, salami sandwiches and pre-packaged snacks are the most frequently consumed solid foods in all BMI classes. 93.6% ate afternoon snack for the most part at home, even if 12% of children reported consuming it elsewhere; fruit juice and tea with pizza, sandwiches and pre-packaged snacks are still the most highly consumed foods by all children's BMI classes. The consumption frequency of breakfast (P < 0.001), mid-morning (P < 0.05) and afternoon snack (P < 0.05) of 8-9 y-old Tuscany children decrease with increase the children's BMI classes. The same tendency may be noted for the consumption frequency of breakfast in relation to mother's BMI (P < 0.05) and their education level (P < 0.05). This data strengthens the thesis that some home environments can affect the children's eating behaviours. CONCLUSION: No substantial differences in food choices at the meals analyzed were determined among normal weight, overweight and obese children. Children of normal weight had a greater tendency to consume meals more regularly. Mother's BMI and their education level can have influence on children's eating behaviours.

Use of an Amplatz Canine Ductal Occluder (ACDO) device to close an acquired aortopulmonary fistula with a hybrid approach in a dog.

A 2-year-old recently spayed female Rottweiler was referred as an emergency with cardiac tamponade and the presence of an anomalous retrograde flow in the pulmonary artery. Echocardiography and angiography demonstrated a left-to-right aortopulmonary fistula. Clinical history and data indicated a possible infectious aetiology. Antibiotics and heart failure medications were administered for 30 days before intervention. Initial attempt at insertion of an Amplatz occluder by means of a percutaneous catheterization technique was tried but a safe release of the device was judged to be not possible due to the angle and the fragile and irregular margins of the window. A decision was made to proceed with a hybrid technique combining thoracotomy and direct pulmonary artery catheterization. This hybrid approach was successful with resolution of congestive heart failure with only residual mild paraprosthetic leakage.

Analgesic, antiulcer, antithrombotic drugs and organ damage: a population-based case-control study.

AIM: Oral medication is of paramount importance for pain treatment. Analgesics, antiulcer (AUDs) and antithrombotic drugs (ATDs) are often coprescribed in elderly people. Non-steroidal anti-inflammatory drugs (NSAIDs) require AUDs to lower the risk of peptic ulcer, and potentially interfere with ATDs. The aim of this study was to quantify the prevalence of NSAID use in patients with gastrointestinal, cardiac or kidney damage in the year 2013, compared to the general population. METHODS: We performed a population-based case-control study in the Republic of San Marino to evaluate the Odds-Ratios for upper gastrointestinal damage (gastroduodenal ulcers and/or erosions, GUE), ischemic heart disease (IHD), heart failure (HF), and renal function impairment (assessed using the CKD-EPI formula), in people who had taken AUDs, ATDs, or NSAIDs in the previous 90 days, versus people who had not taken such drugs in the same period of time. RESULTS: We found that AUDs decreased the OR for GUE (OR: 0.762; CI:0.598-0.972), while ATDs and NSAIDs increased the risk (OR: 1.238 and CI: 0.935-1.683; OR:1.203 and CI:0.909-1.592, respectively). NSAIDs seemed to increase the risk of IHD, although this was not statistically significant (OR=1.464; CI=0.592-3.621). AUDs and ATDs significantly increased the risk of renal function impairment (OR=1.369 and CI=1.187-1.579; OR=1.818 and CI=1.578-2.095, respectively), while this effect was not observed for NSAIDs. CONCLUSION: NSAIDs may induce gastrointestinal and cardiovascular damage, not only by themselves, but also when used concomitantly with common medications such as AUDs or ATDs, due to additive and/or synergistic effects. We performed a "pragmatic" analysis of the association of organ damage with use of NSAIDs/AUDs/ATDs, including patient age, treatment duration and dose, to allow for an immediate application of our findings to everyday clinical practice.

ERP indexes of functional differences in brain activation during proper and common names retrieval.

Functional neuroimaging and neuropsychological findings suggest that memory retrieval of common and proper names is subserved by different neuro-functional systems but little is known about the topographic localization of neural generators. In the present study brain electrical activity was recorded with a high density electrode montage in healthy young volunteers during lexical retrieval upon written definition. ERPs spatio-temporal mapping showed on one side a strong activation of left anterior temporal and left central-frontal areas for proper names, and on the other side a greater involvement of occipital areas for common names retrieval. The specific pattern of bio-electrical activity recorded during proper names retrieval might index the activation of neural circuits for recalling names of high contextual complexity, poor of sensory-motor associations and dependent on precise spatio-temporal coordinates.

Electrophysiological evidence of a perceptual precedence of global vs. local visual information.

Aim of the present study was to investigate the mechanisms of attentional selection of hierarchically organized visual patterns (compound letter stimuli), while subjects were engaged in target selection at either the global or local level. Event-related brain potentials (ERPs) were recorded using a high density electrode montage. Reaction times (RTs) to target stimuli were also recorded. RT data indicated the interference effect of global incongruent information with the local one. ERP data were consistent with behavioral data. In fact, the early sensory N115 component recorded at the primary visual areas exhibited smaller responses to locally attended elements when the global configuration was incongruent rather than congruent, suggesting an interference effect of the global with the local level. Conversely, no interference effect was found for globally attended configurations. These results strongly support the view of a perceptual advantage of globally conveyed information, very likely mediated by low spatial frequency channels. At later processing levels, N1 and P3 components were faster and larger when attention was paid to the global configuration. The difference between target and nontarget responses, indexing the attentional target selection, yielded a broad occipital-temporal negativity focused onto the left hemisphere in the attend-local, and over the right hemisphere in the attend-global condition. The present findings indicate a hemispheric asymmetry in cerebral activation during local/global processing. In addition, they provide robust evidence of a sensory precedence of global information.

ERP and RT signs of a rightward bias for spatial orienting in a split-brain patient.

Neuropsychological data have shown that the two cerebral hemispheres differ in the control of spatial attention. The present study investigated hemispheric asymmetries and visuomotor integration in a split-brain patient and three control subjects. Simple reaction times (RTs) and event-related potentials (ERPs) were recorded to lateralized stimuli presented at different eccentricities in the left and right visual hemifields. Both electrophysiological and behavioural data showed that, unlike controls, the split-brain patient showed a strong rightward attentional bias resulting in shorter RTs and larger P300 potentials to stimuli falling in the rightmost space. Furthermore, ERPs also showed that while the RH has a bilateral control of visual space, the LH spatial orienting capability is most restricted to the contralateral hemifield.