The Effect of Sleep Deprivation on Brain Fingerprint Stability: A Magnetoencephalography Validation Study

This study examined the stability of the functional connectome (FC) over time using fingerprint analysis in healthy subjects. Additionally, it investigated how a specific stressor, namely sleep deprivation, affects individuals' differentiation. To this aim, 23 healthy young adults underwent magnetoencephalography (MEG) recording at three equally spaced time points within 24 h: 9 a.m., 9 p.m., and 9 a.m. of the following day after a night of sleep deprivation. The findings indicate that the differentiation was stable from morning to evening in all frequency bands, except in the delta band. However, after a night of sleep deprivation, the stability of the FCs was reduced. Consistent with this observation, the reduced differentiation following sleep deprivation was found to be negatively correlated with the effort perceived by participants in completing the cognitive task during sleep deprivation. This correlation suggests that individuals with less stable connectomes following sleep deprivation experienced greater difficulty in performing cognitive tasks, reflecting increased effort.

Topological changes of fast large-scale brain dynamics in mild cognitive impairment predict early memory impairment: a resting-state, source reconstructed, magnetoencephalography study

Functional connectivity has been used as a framework to investigate widespread brain interactions underlying cognitive deficits in mild cognitive impairment (MCI). However, many functional connectivity metrics focus on the average of the periodic activities, disregarding the aperiodic bursts of activity (i.e., the neuronal avalanches) characterizing the large-scale dynamic activities of the brain. Here, we apply the recently described avalanche transition matrix framework to source-reconstructed magnetoencephalography signals in a cohort of 32 MCI patients and 32 healthy controls to describe the spatio-temporal features of neuronal avalanches and explore their topological properties. Our results showed that MCI patients showed a more centralized network (as assessed by higher values of the degree divergence and leaf fraction) as compared to healthy controls. Furthermore, we found that the degree divergence (in the theta band) was predictive of hippocampal memory impairment. These findings highlight the role of the changes of aperiodic bursts in clinical conditions and may contribute to a more thorough phenotypical assessment of patients.

Brain fingerprint is based on the aperiodic, scale-free, neuronal activity

Subject differentiation bears the possibility to individualize brain analyses. However, the nature of the processes generating subject-specific features remains unknown. Most of the current literature uses techniques that assume stationarity (e.g., Pearson's correlation), which might fail to capture the non-linear nature of brain activity. We hypothesize that non-linear perturbations (defined as neuronal avalanches in the context of critical dynamics) spread across the brain and carry subject-specific information, contributing the most to differentiability. To test this hypothesis, we compute the avalanche transition matrix (ATM) from source-reconstructed magnetoencephalographic data, as to characterize subject-specific fast dynamics. We perform differentiability analysis based on the ATMs, and compare the performance to that obtained using Pearson's correlation (which assumes stationarity). We demonstrate that selecting the moments and places where neuronal avalanches spread improves differentiation (P < 0.0001, permutation testing), despite the fact that most of the data (i.e., the linear part) are discarded. Our results show that the non-linear part of the brain signals carries most of the subject-specific information, thereby clarifying the nature of the processes that underlie individual differentiation. Borrowing from statistical mechanics, we provide a principled way to link emergent large-scale personalized activations to non-observable, microscopic processes.

Highly Sensitive Tunable Magnetometer Based on Superconducting Quantum Interference Device

In the present article, experimental results regarding fully integrated superconducting quantum interference devices (SQUID), including a circuit to tune and optimize the main sensor device characteristics, are reported. We show the possibility of modifying the critical current of a SQUID magnetometer in liquid helium by means of a suitable heating circuit. This allows us to improve the characteristics of the SQUID sensor and in particular to optimize the voltage-magnetic flux characteristic and the relative transfer factor (responsivity) and consequently to also improve the flux and magnetic field noise. It is also possible to reset the SQUID sensor in case of entrapment of magnetic flux, avoiding taking it out of the helium bath. These results are very useful in view of most SQUID applications such as those requiring large multichannel systems in which it is desirable to optimize and eventually reset the magnetic sensors in a simple and effective way.

High-Quality Ferromagnetic Josephson Junctions Based on Aluminum Electrodes

Aluminum Josephson junctions are the building blocks for the realization of superconducting quantum bits. Attention has been also paid to hybrid ferromagnetic Josephson junctions, which allow switching between different magnetic states, making them interesting for applications such as cryogenic memories, single-photon detectors, and spintronics. In this paper, we report on the fabrication and characterization of high-quality ferromagnetic Josephson junctions based on aluminum technology. We employed an innovative fabrication process inspired by niobium-based technology, allowing us to obtain very high-quality hybrid aluminum Josephson junctions; thus, supporting the use of ferromagnetic Josephson junctions in advanced quantum circuits. The fabrication process is described in detail and the main DC transport properties at low temperatures (current-voltage characteristic, critical current as a function of the temperature, and the external magnetic field) are reported. Here, we illustrate in detail the fabrication process, as well as the main DC transport properties at low temperatures (current-voltage characteristic, critical current as a function of the temperature, and the external magnetic field).

The progressive loss of brain network fingerprints in Amyotrophic Lateral Sclerosis predicts clinical impairment

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterised by functional connectivity alterations in both motor and extra-motor brain regions. Within the framework of network analysis, fingerprinting represents a reliable approach to assess subject-specific connectivity features within a given population (healthy or diseased). Here, we applied the Clinical Connectome Fingerprint (CCF) analysis to source-reconstructed magnetoencephalography (MEG) signals in a cohort of seventy-eight subjects: thirty-nine ALS patients and thirty-nine healthy controls. We set out to develop an identifiability matrix to assess the extent to which each patient was recognisable based on his/her connectome, as compared to healthy controls. The analysis was performed in the five canonical frequency bands. Then, we built a multilinear regression model to test the ability of the "clinical fingerprint" to predict the clinical evolution of the disease, as assessed by the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-r), the King's disease staging system, and the Milano-Torino Staging (MiToS) disease staging system. We found a drop in the identifiability of patients in the alpha band compared to the healthy controls. Furthermore, the "clinical fingerprint" was predictive of the ALSFRS-r (p = 0.0397; β = 32.8), the King's (p = 0.0001; β = -7.40), and the MiToS (p = 0.0025; β = -4.9) scores. Accordingly, it negatively correlated with the King's (Spearman's rho = -0.6041, p = 0.0003) and MiToS scales (Spearman's rho = -0.4953, p = 0.0040). Our results demonstrated the ability of the CCF approach to predict the individual motor impairment in patients affected by ALS. Given the subject-specificity of our approach, we hope to further exploit it to improve disease management.

A night of sleep deprivation alters brain connectivity and affects specific executive functions

Sleep is a fundamental physiological process necessary for efficient cognitive functioning especially in relation to memory consolidation and executive functions, such as attentional and switching abilities. The lack of sleep strongly alters the connectivity of some resting-state networks, such as default mode network and attentional network. In this study, by means of magnetoencephalography (MEG) and specific cognitive tasks, we investigated how brain topology and cognitive functioning are affected by 24 h of sleep deprivation (SD). Thirty-two young men underwent resting-state MEG recording and evaluated in letter cancellation task (LCT) and task switching (TS) before and after SD. Results showed a worsening in the accuracy and speed of execution in the LCT and a reduction of reaction times in the TS, evidencing thus a worsening of attentional but not of switching abilities. Moreover, we observed that 24 h of SD induced large-scale rearrangements in the functional network. These findings evidence that 24 h of SD is able to alter brain connectivity and selectively affects cognitive domains which are under the control of different brain networks.

European consensus on patient contact shielding

Patient contact shielding has been in use for many years in radiology departments in order to reduce the effects and risks of ionising radiation on certain organs. New technologies in projection imaging and CT scanning such as digital receptors and automatic exposure control (AEC) systems have reduced doses and improved image consistency. These changes and a greater understanding of both the benefits and the risks from the use of shielding have led to a review of shielding use in radiology. A number of professional bodies have already issued guidance in this regard. This paper represents the current consensus view of the main bodies involved in radiation safety and imaging in Europe: European Federation of Organisations for Medical Physics, European Federation of Radiographer Societies, European Society of Radiology, European Society of Paediatric Radiology, EuroSafe Imaging, European Radiation Dosimetry Group (EURADOS), and European Academy of DentoMaxilloFacial Radiology (EADMFR). It is based on the expert recommendations of the Gonad and Patient Shielding (GAPS) Group formed with the purpose of developing consensus in this area. The recommendations are intended to be clear and easy to use. They are intended as guidance, and they are developed using a multidisciplinary team approach. It is recognised that regulations, custom and practice vary widely on the use of patient shielding in Europe and it is hoped that these recommendations will inform a change management program that will benefit patients and staff.

Brain networks and cognitive impairment in Parkinson's disease

Aim The aim of the present study is to investigate the relations between both functional connectivity and brain networks with cognitive decline, in patients with Parkinson's disease (PD). Introduction PD phenotype is not limited to motor impairment but, rather, a wide range of non-motor disturbances can occur, cognitive impairment being one of the commonest. However, how the large-scale organization of brain activity differs in cognitively impaired patients, as opposed to cognitively preserved ones, remains poorly understood. Methods Starting from source-reconstructed resting-state magnetoencephalography data, we applied the PLM to estimate functional connectivity, globally and between brain areas, in PD patients with and without cognitive impairment (respectively PD-CI and PD-NC), as compared to healthy subjects (HS). Furthermore, using graph analysis, we characterized the alterations in brain network topology and related these, as well as the functional connectivity, to cognitive performance. Results We found reduced global and nodal PLM in several temporal (fusiform gyrus, Heschl's gyrus and inferior temporal gyrus), parietal (postcentral gyrus), and occipital (lingual gyrus) areas within the left hemisphere, in the gamma band, in PD-CI patients, as compared to PD-NC and HS. With regard to the global topological features, PD-CI patients, as compared to HS and PD-NC patients, showed differences in multi frequencies bands (delta, alpha, gamma) in the Leaf fraction, Tree hierarchy (both higher in PD-CI) and Diameter (lower in PD-CI). Finally, we found statistically significant correlations between the MoCA test and both the Diameter in delta band and the Tree Hierarchy in the alpha band. Conclusion Our work points to specific large-scale rearrangements that occur selectively in cognitively compromised PD patients and correlated to cognitive impairment.

Neuronal Avalanches to Study the Coordination of Large-Scale Brain Activity: Application to Rett Syndrome

Many complex systems, such as the brain, display large-scale coordinated interactions that create ordered patterns. Classically, such patterns have been studied using the framework of criticality, i.e., at a transition point between two qualitatively distinct patterns. This kind of system is generally characterized by a scale-invariant organization, in space and time, optimally described by a power-law distribution whose slope is quantified by an exponent α. The dynamics of these systems is characterized by alternating periods of activations, called avalanches, with quiescent periods. To maximize its efficiency, the system must find a trade-off between its stability and ease of propagation of activation, which is achieved by a branching process. It is quantified by a branching parameter σ defined as the average ratio between the number of activations in consecutive time bins. The brain is itself a complex system and its activity can be described as a series of neuronal avalanches. It is known that critical aspects of brain dynamics are modeled with a branching parameter σ = , and the neuronal avalanches distribution fits well with a power law distribution exponent α = -3/2. The aim of our work was to study a self-organized criticality system in which there was a change in neuronal circuits due to genetic causes. To this end, we have compared the characteristics of neuronal avalanches in a group of 10 patients affected by Rett syndrome, during an open-eye resting-state condition estimated using magnetoencephalography, with respect to 10 healthy subjects. The analysis was performed both in broadband and in the five canonical frequency bands. We found, for both groups, a branching parameter close to 1. In this critical condition, Rett patients show a lower distribution parameter α in the delta and broadband. These results suggest that the large-scale coordination of activity occurs to a lesser extent in RTT patients.

Core-Shell Magnetic Nanoparticles for Highly Sensitive Magnetoelastic Immunosensor

A magnetoelastic (ME) biosensor for wireless detection of analytes in liquid is described. The ME biosensor was tested against human IgG in the range 0-20 μg∙mL-1. The sensing elements, anti-human IgG produced in goat, were immobilized on the surface of the sensor by using a recently introduced photochemical immobilization technique (PIT), whereas a new amplification protocol exploiting gold coated magnetic nanoparticles (core-shell nanoparticles) is demonstrated to significantly enhance the sensitivity. The gold nanoflowers grown on the magnetic core allowed us to tether anti-human IgG to the nanoparticles to exploit the sandwich detection scheme. The experimental results show that the 6 mm × 1 mm × 30 μm ME biosensor with an amplification protocol that uses magnetic nanoparticles has a limit of detection (LOD) lower than 1 nM, works well in water, and has a rapid response time of few minutes. Therefore, the ME biosensor is very promising for real-time wireless detection of pathogens in liquids and for real life diagnostic purpose.

Detection of Magnetomechanical Effect in Structural Steel Using GMR 2nd Order Gradiometer Based Sensors

The magneto-mechanical behaviour of structural steel specimens stressed up to the plastic deformation stage was investigated using a 2nd order gradiometer based on Giant Magneto Resistive (GMR) sensors. The correlation between the gradient of the magnetization and the dislocation density before the crack initiation inside the test material was reported. The capability of the GMR scanning sensor to detect the residual magnetization due to the tensile stress with a non-invasive technique was demonstrated.

CONSERVATIVE MANAGEMENT OF CHYLOUS ASCITES AFTER ONCOLOGICAL SURGERY FOR PERIPHERAL NEUROBLASTIC TUMORS IN PEDIATRIC PATIENTS

Chylous ascites may complicate the postoperative course of abdominal surgery mainly due to the iatrogenic disruption of the lymphatic channels during extensive retroperitoneal dissection. Sparse data are available regarding treatment; however, in many cases a recommended first-line treatment approach is by way of enteral feeding, consisting of a formula high in medium-chain triglycerides (MCTs) together with a complete total parenteral nutrition teamed with somatostatin (or an equivalent). Nonetheless, the ligation of chylous fistulae, together with the application of Fibrin glue, as well as the creation of peritoneal-venous shunts have also been documented. The aims of this study are to document incidence of postoperative chylous ascites following resection of abdominal peripheral neuroblastic tumors, evaluate efficacy of the management of chylous ascites, and investigate the main risk factors. A survey was carried out over a span of six years, from March 2010 to March 2016 at Giannina Gaslini Children's Hospital involving seventy-seven children with resections of peripheral neuroblastic tumors. Incidence rate of postoperative chylous ascites following a normal diet was 9% (n=7). Treatment using total parenteral nutrition with octreotide resulted in a complete recovery from chylous ascites within a 20 day period without recurrence. Length of operative time, nephrectomy, and the extension of lymphadenectomy were all significantly associated with a higher incidence of postoperative chylous ascites (p&lt;0.05) which also lengthened hospital stay (p&lt;0.05) and possibly delayed beginning adjuvant chemotherapy.

Conservative management of chylous ascites after oncological surgery for peripheral neuroblastic tumors in pediatric patients

Chylous ascites may complicate the postoperative course of abdominal surgery mainly due to the iatrogenic disruption of the lymphatic channels during extensive retroperitoneal dissection. Sparse data are available regarding treatment; however, in many cases a recommended first-line treatment approach is by way of enteral feeding, consisting of a formula high in medium-chain triglycerides (MCTs) together with a complete total parenteral nutrition teamed with somatostatin (or an equivalent). Nonetheless, the ligation of chylous fistulae, together with the application of Fibrin glue, as well as the creation of peritoneal-venous shunts have also been documented. The aims of this study are to document incidence of postoperative chylous ascites following resection of abdominal peripheral neuroblastic tumors, evaluate efficacy of the management of chylous ascites, and investigate the main risk factors. A survey was carried out over a span of six years, from March 2010 to March 2016 at Giannina Gaslini Children's Hospital involving seventy-seven children with resections of peripheral neuroblastic tumors. Incidence rate of postoperative chylous ascites following a normal diet was 9% (n=7). Treatment using total parenteral nutrition with octreotide resulted in a complete recovery from chylous ascites within a 20 day period without recurrence. Length of operative time, nephrectomy, and the extension of lymphadenectomy were all significantly associated with a higher incidence of postoperative chylous ascites (p<0.05) which also lengthened hospital stay (p<0.05) and possibly delayed beginning adjuvant chemotherapy.

Amnestic Mild Cognitive Impairment Is Associated With Frequency-Specific Brain Network Alterations in Temporal Poles

There is general agreement that the neuropathological processes leading to Alzheimer’s disease (AD) begin decades before the clinical onset. In order to detect early topological changes, we applied functional connectivity and network analysis to magnetoencephalographic (MEG) data obtained from 16 patients with amnestic Mild Cognitive Impairment (aMCI), a prodromal stage of AD, and 16 matched healthy control (HCs). Significant differences between the two groups were found in the theta band, which is associated with memory processes, in both temporal poles (TPs). In aMCI, the degree and betweenness centrality (BC) were lower in the left superior TP, whereas in the right middle TP the BC was higher. A statistically significant negative linear correlation was found between the BC of the left superior TP and a delayed recall score, a sensitive marker of the “hippocampal memory” deficit in early AD. Our results suggest that the TPs, which are involved early in AD pathology and belong to the memory circuitry, have an altered role in the functional network in aMCI.

Brain functional networks become more connected as amyotrophic lateral sclerosis progresses: a source level magnetoencephalographic study

This study hypothesizes that the brain shows hyper connectedness as amyotrophic lateral sclerosis (ALS) progresses. 54 patients (classified as "early stage" or "advanced stage") and 25 controls underwent magnetoencephalography and MRI recordings. The activity of the brain areas was reconstructed, and the synchronization between them was estimated in the classical frequency bands using the phase lag index. Brain topological metrics such as the leaf fraction (number of nodes with degree of 1), the degree divergence (a measure of the scale-freeness) and the degree correlation (a measure of disassortativity) were estimated. Betweenness centrality was used to estimate the centrality of the brain areas. In all frequency bands, it was evident that, the more advanced the disease, the more connected, scale-free and disassortative the brain networks. No differences were evident in specific brain areas. Such modified brain topology is sub-optimal as compared to controls. Within this framework, our study shows that brain networks become more connected according to disease staging in ALS patients.

Superconductive quantum interference magnetometer with high sensitivity achieved by an induced resonance

A fully integrated low noise superconducting quantum interference device (SQUID) in a magnetometer configuration is presented. An intrinsic high voltage responsivity as high as 500 μV/Φ0 has been obtained by introducing a resonance in the voltage - magnetic flux characteristic. This resonance is induced by an integrated superconducting coil surrounding the pick-up coil and connected to one end of the SQUID output. The SQUID magnetometer exhibits a spectral density of magnetic field noise as low as 3 fT/Hz(1/2). In order to verify the suitability of the magnetometer, measurements of bandwidth and slew rate have been performed and compared with those of the same device without the resonance and with additional positive feedback. Due to their good characteristics such devices can be employed in a large number of applications including biomagnetism.

Multichannel system based on a high sensitivity superconductive sensor for magnetoencephalography

We developed a multichannel system based on superconducting quantum interference devices (SQUIDs) for magnetoencephalography measurements. Our system consists of 163 fully-integrated SQUID magnetometers, 154 channels and 9 references, and all of the operations are performed inside a magnetically-shielded room. The system exhibits a magnetic field noise spectral density of approximatively 5 fT/Hz(1=2). The presented magnetoencephalography is the first system working in a clinical environment in Italy.

Robot services for elderly with cognitive impairment: testing usability of graphical user interfaces

BACKGROUND

Socially assistive robotics for elderly care is a growing field. However, although robotics has the potential to support elderly in daily tasks by offering specific services, the development of usable interfaces is still a challenge. Since several factors such as age or disease-related changes in perceptual or cognitive abilities and familiarity with computer technologies influence technology use they must be considered when designing interfaces for these users.

OBJECTIVE

This paper presents findings from usability testing of two different services provided by a social assistive robot intended for elderly with cognitive impairment: a grocery shopping list and an agenda application. The main goal of this study is to identify the usability problems of the robot interface for target end-users as well as to isolate the human factors that affect the use of the technology by elderly.

METHODS

Socio-demographic characteristics and computer experience were examined as factors that could have an influence on task performance. A group of 11 elderly persons with Mild Cognitive Impairment and a group of 11 cognitively healthy elderly individuals took part in this study. Performance measures (task completion time and number of errors) were collected.

RESULTS

Cognitive profile, age and computer experience were found to impact task performance. Participants with cognitive impairment achieved the tasks committing more errors than cognitively healthy elderly. Instead younger participants and those with previous computer experience were faster at completing the tasks confirming previous findings in the literature.

CONCLUSIONS

The overall results suggested that interfaces and contents of the services assessed were usable by older adults with cognitive impairment. However, some usability problems were identified and should be addressed to better meet the needs and capacities of target end-users.

Surface sensitivity of Rayleigh anomalies in metallic nanogratings

Sensing schemes based on Rayleigh anomalies (RAs) in metal nanogratings exhibit an impressive bulk refractive-index sensitivity determined solely by the grating period. However, the surface sensitivity (which is a key figure of merit for label-free chemical and biological sensing) needs to be carefully investigated to assess the actual applicability of this technological platform. In this paper, we explore the sensitivity of RAs in metal nanogratings when local refractive-index changes are considered. Our studies reveal that the surface sensitivity deteriorates up to two orders of magnitude by comparison with the corresponding bulk value; interestingly, this residual sensitivity is not attributable to the wavelength shift of the RAs, which are completely insensitive to local refractive-index changes, but rather to a strictly connected plasmonic effect. Our analysis for increasing overlay thickness reveals an ultimate surface sensitivity that approaches the RA bulk value, which turns out to be the upper-limit of grating-assisted surface-plasmon-polariton sensitivities.

Nano Superconducting QUantum Interference Device sensors for magnetic nanoparticle detection

In this paper, Superconducting QUantum Interference Devices (SQUIDs) based on single layer Nb nanobridge Josephson junctions are described. Devices, with loop area ranging from 4 to 0.5 microm2, have been patterned by Electron Beam Lithography (EBL) in a 20 nm thick Nb layer, achieving a responsivity of about 30 microA/phi0. Magnetization measurements have been performed via switching current measurements at a temperature T = 4.2 K. Preliminary detection of Silica-magnetite (Fe3O4-SiO2) core/shell nanoparticle cluster has been proven.

An ultralow noise current amplifier based on superconducting quantum interference device for high sensitivity applications

An integrated ultrahigh sensitive current amplifier based on a niobium dc superconducting quantum interference device (SQUID) has been developed. The sensor design is based on a multiturn signal coil coupled to a suitable SQUID magnetometer. The signal coil consists of 60 square niobium turns tightly coupled to a superconducting flux transformer of a SQUID magnetometer. The primary coil (pick-up coil) of the flux transformer has been suitably designed in order to accommodate the multiturn input coil. It has a side length of 10 mm and a width of 2.4 mm. In such a way we have obtained a signal current to magnetic flux transfer coefficient (current sensitivity) as low as 62 nA∕Φ(0). The sensor has been characterized in liquid helium by using a direct coupling low noise readout electronic and a standard modulated electronic in flux locked loop configuration for the noise measurements. Beside the circuit complexity, the sensor has exhibited a smooth and free resonance voltage-flux characteristic guaranteeing a reliable and a stable working operation. Considering a SQUID magnetic flux noise of S(Φ)(1∕2) = 1.8 μΦ(0)∕Hz(1∕2) at T = 4.2 K, a current noise as low as 110 fA∕Hz(1∕2) is obtained. Such a value is about a factor two less than the noise of other SQUIDs of the same category. As an application, Nyquist noise measurements of integrated test resistors using the current sensing noise thermometer technique are reported. Due to its high performance such a sensor can be employed in all applications requiring an extremely current sensitivity like the readout of the gravitational wave detectors and the current sensing noise thermometry.

Multislice CT in congenital bronchopulmonary malformations in children

Congenital bronchopulmonary malformations encompass a wide spectrum of pathologies involving the lungs, trachea and bronchi, pulmonary vessels, and oesophagus. These developmental lesions are often isolated, but the association of two or more anomalies is not infrequent. Contrast-enhanced multidetector computed tomography (MDCT), thanks to multiplanar and 3D reconstructions, allows for detailed studies of these malformations, achieving better accuracy compared with conventional techniques such as chest X-ray, fluoroscopy, ventilation and perfusion scintigraphy and ultrasonography. MDCT is characterised by fast data acquisition and does not require sedation in the majority of cases. The main drawbacks of MDCT are the use of ionising radiation and - in many cases -contrast media. Recently, improved CT scanners and optimised CT protocols have made available to children all the benefits of MDCT, thanks to a significant reduction in radiation dose and an improved risk-benefit ratio. The aim of our paper was to evaluate MDCT in children with bronchopulmonary malformations by reporting our experience (about 2,400 studies in 30 months with a 64-slice MDCT scanner) and comparing it with the available literature.

Shifting from open surgical cut down to ultrasound-guided percutaneous central venous catheterization in children: learning curve and related complications

PURPOSE

Tunneled indwelling central venous catheters (CVC) are essential in the management of children with cancer, hematological, nephrological disorders and for parenteral nutrition. The aim of this study is to present the experience of a single center of the transition from traditional open surgical cut down procedure (OSC) to ultrasound (US)-guided percutaneous CVC insertion, focusing on learning curve and related complications.

METHODS

All CVCs inserted between April 2008 and November 2009 in children at the Gaslini Children Hospital were revised, and data on methods of cannulation, intraoperative and device-related complications and re-intervention were recorded.

RESULTS

194 CVCs were positioned in 188 patients. 128 out of 194 CVCs were positioned through an OSC technique, whereas the remaining 66 CVCs were inserted percutaneously with US guidance. Of the 27 recorded complications, 15 were mechanical events, 7 cases developed infection, whereas the remaining 5 (2.6%) were classified as intraoperative complications. A second surgical procedure was described in 23 (11.8%) cases.

CONCLUSION

Shifting from OSC to US-guided percutaneous CVC insertion inevitably involves a challenging learning curve which is generally associated with high complication rates. Complications progressively decrease once a good experience in US guidance and percutaneous technique has been obtained.

An integrated superconductive magnetic nanosensor for high-sensitivity nanoscale applications

An integrated magnetic nanosensor based on a niobium dc SQUID (superconducting quantum interference device) for nanoscale applications is presented. The sensor, having a washer shape with a hole of 200 nm and two Josephson-Dayem nanobridges of 80 nm × 100 nm, consists of a Nb(30 nm)/Al(30 nm) bilayer patterned by electron beam lithography (EBL) and shaped by lift-off and reactive ion etch (RIE) processes. The presence of the niobium coils, integrated on-chip and tightly coupled to the SQUID, allows us to easily excite the sensor in order to get the voltage-flux characteristics and to flux bias the SQUID at its optimal point. The measurements were performed at liquid helium temperature. A voltage swing of 75 µV and a maximum voltage-flux transfer coefficient (responsivity) as high as 1 mV/Φ(0) were directly measured from the voltage-flux characteristic. The noise measurements were performed in open loop mode, biasing the SQUID with a dc magnetic flux at its maximum responsivity point and using direct-coupled low-noise readout electronics. A white magnetic flux noise spectral density as low as 2.5 μΦ(0) Hz(-1/2) was achieved, corresponding to a magnetization or spin sensitivity in units of the Bohr magneton of 100 spin Hz(-1/2). Possible applications of this nanosensor can be envisaged in magnetic detection of nanoparticles and small clusters of atoms and molecules, in the measurement of nanoobject magnetization, and in quantum computing.

Vesicoureteral reflux and ureteropelvic junction obstruction in children with horseshoe kidney: treatment and outcome

PURPOSE

Horseshoe kidney is the most common renal fusion anomaly. We determined the treatment and outcome of vesicoureteral reflux and ureteropelvic junction obstruction in children with horseshoe kidney.

MATERIALS AND METHODS

We reviewed the medical and radiological records of 52 consecutive children, including 32 boys and 20 girls, in whom horseshoe kidney was diagnosed at 2 children's hospitals during 1990 to 1999. Patient age at diagnosis was 1 day to 12 years (mean 3.9 years). In 2 children with horseshoe kidney neuropathic bladder was secondary to spina bifida and they were excluded from study. The diagnosis was made in all cases by abdominal ultrasound and confirmed by excretory urography or (99m)technetium-dimercaptosuccinic acid scan. Voiding cystourethrography was performed in 40 cases (80%). Patients were followed for 2 to 11 years (mean 4.2).

RESULTS

Associated urological anomalies were identified in 26 patients (52%) with horseshoe kidney, including primary vesicoureteral reflux in 13, ureteropelvic junction obstruction in 12 and ectopic ureter in 1. Surgical intervention to correct the anomalies in 15 of the 26 children (58%) involved pyeloplasty in 8, ureteral reimplantation in 2, endoscopic treatment for vesicoureteral reflux in 2, ureterolithotomy in 1, upper pole heminephrectomy in 1 and valve fulguration in 1. No significant complications were observed in surgically treated patients.

CONCLUSIONS

More than half of the patients with a clinically symptomatic horseshoe kidney have vesicoureteral reflux or ureteropelvic junction obstruction. Many patients with horseshoe kidney require surgical intervention for associated urological anomalies with good results.

Lichen sclerosus et atrophicus in children with phimosis and hypospadias

This prospective study was designed to evaluate the incidence of lichen sclerosus et atrophicus (LSA) in a pediatric population with hypospadias and phimosis in order to discuss the indications for circumcision and utilization of preputial skin for urethral surgery. All 115 boys, 55 with congenital phimosis, 45 with acquired phimosis, 13 with hypospadias, and 2 with recurrent chronic balanitis, underwent full-thickness biopsies of the foreskin that were examined by a single pathologist. Of the patients with acquired phimosis, 88% showed inflammatory features in the foreskin; 60% had LSA. Of the patients with congenital phimosis, 82% showed inflammatory disease in the prepuce; 30% had LSA. Of the patients operated upon for hypospadias, 61% showed histologic findings of chronic inflammation of the foreskin and LSA was evident in 15%. The high incidence of LSA in the prepuce of patients with phimosis suggests that circumcision should be performed to correct this disease. The frequent presence of chronic inflammation is a possible cause of stenosis when the foreskin is used to perform a urethroplasty in patients with hypospadias.

Outbreak of African tick-bite fever in six Italian tourists returning from South Africa

In May 1999, a cluster of cases of African tick-bite fever was detected in six Italian tourists who had returned from South Africa. All of the patients had moderate fever and cutaneous eschars. Regional lymphangitis was observed in three of the patients and skin rash in two. By comparing the number of eschars with the number of detectable bite sites it was suggested that at least two-thirds of the biting vectors were capable of transmitting Rickettsia africae. The clinical course of disease was mild in all cases, and all but one of the patients recovered spontaneously before antibiotic treatment was initiated. The diagnosis of African tick-bite fever was confirmed serologically using both microimmunofluorescence and Western blot tests.

Conformationally restricted PACAP27 analogues incorporating type II/II' IBTM beta-turn mimetics. Synthesis, NMR structure determination, and binding affinity

To probe the importance of a proposed beta-turn within residues S9-R12 of PACAP for recognition by VIP/PACAP receptors, compounds 1 and 2, two conformationally restricted analogues of PACAP27 incorporating respectively (S)- or (R)-IBTM as type II or II' beta-turn dipeptide mimetic at the Y10-S11 position, were synthesized. According to 1H NMR conformational analyses in aqueous solution and 30% TFE, both PACAP27 and the [S-IBTM(10,11)]PACAP27 analogue 1 adopt similar ordered structures. PACAP27 shows an N-terminal disordered region (residues H1-F6) and an alpha-helical conformation within segment T7-L27. For residues S9-R12, our data seem more compatible with a segment of the alpha-helix than with the beta-turn previously proposed for this fragment. In compound 1 the alpha-helix, also spanning T7-L27 residues, appears slightly distorted at the N-terminus relative to the native peptide. Although this distortion could lead to the marked decrease in binding affinity of this compound at the VIP/PACAP receptors, the lack of the Y10 side chain in analogues 1 and 2 could also significantly affect the binding of these compounds.

Medium-term results after cholecystectomy in patients younger than 10 years

BACKGROUND

Gallbladder stones are a well-known and widely studied problem in children. Hematological disorders are the most common diseases that can cause cholelithiasis. However, in the last few years, the proportion of children with idiopathic cholelithiasis has increased 50%. Herein, we present a prospective study on laparoscopic cholecystectomy in a selected group of patients aged < 10 years.

METHODS

Fifty-eight patients aged < 10 years underwent laparoscopic cholecystectomy for stones in the period 1992-99. The female/male ratio was 1.5, the mean age was 8 years (range, 2-10), and the mean weight was 30 kg. In all patients, parenteral nutrition, fasting state, and prolonged use of antibiotics had been suspended for > or = 6 months, and conservative treatment had been tried for > or = 12 months in the absence of symptoms of stone migration. All the patients were followed up after surgery: clinically at 1,6,12, and 36 months and by ultrasound at 1, 12, and 36 months. Liver function and hematological tests were performed in case of symptoms or if hemolytic disorders were the cause of stones.

RESULTS

The mean operative time was 63 min (range, 30-120) in children undergoing cholecystectomy alone and 150 min in children undergoing associated splenectomy. There were no major complications or reoperations. Minor complications included bleeding from accessory cystic artery (n = 3) and insufflation of the omentum (n = 2). One case was converted to an open procedure due to technical problems. All the children were followed up and no complications were observed.

CONCLUSION

We consider the laparoscopic approach the gold standard for cholecystectomy in children. This procedure does not have a complication rate any higher than open cholecystectomy, and patient follow-up is as good as that of open surgery. Previous abdominal surgery is not a contraindication to laparoscopy.

[Intractable diarrhea and neuroblastoma: report of a clinical case]

One of the typical presentations of neuroblastoma is intractable diarrhea or wdha (watery diarrhea, hypokalemia, achloridria). The case admitted to our Pediatric Surgery Department presented watery diarrhea due to VIP hyperincretion caused by a stage 1 neuroblastoma, whose ablation allowed a complete resolution of the clinical conditions. This case report can be useful in the discussion of the differential diagnosis of the most common clinical pictures.

N-terminal fatty acid substitution increases the leishmanicidal activity of CA(1-7)M(2-9), a cecropin-melittin hybrid peptide

In order to improve the leishmanicidal activity of the synthetic cecropin A-melittin hybrid peptide CA(1-7)M(2-9) (KWKLFKKIGAVLKVL-NH(2)), a systematic study of its acylation with saturated linear fatty acids was carried out. Acylation of the N(epsilon)-7 lysine residue led to a drastic decrease in leishmanicidal activity, whereas acylation at lysine 1, in either the alpha or the epsilon NH(2) group, increased up to 3 times the activity of the peptide against promastigotes and increased up to 15 times the activity of the peptide against amastigotes. Leishmanicidal activity increased with the length of the fatty acid chain, reaching a maximum for the lauroyl analogue (12 carbons). According to the fast kinetics, dissipation of membrane potential, and parasite membrane permeability to the nucleic acid binding probe SYTOX green, the lethal mechanism was directly related to plasma membrane permeabilization.

Pleuropulmonary blastoma

We report a rare case of pleuropulmonary blastoma arising in a 3-year-old boy and involving the middle and upper lobes of the right lung. Radical resection of the mass was achieved by a bilobectomy. Microscopic examination of the histologic sections showed the typical findings of blastemal and mesenchymal areas with focal zones of rhabdomyoblastic and liposarcomatous differentiation. Monthly cycles of chemotherapy consisting of ifosfamide, vincristine and actinomycin D were given for 10 months after surgical resection. Our patient is presently alive and disease-free two years after diagnosis. As complete tumour ablation is essential to prevent local recurrence and allow any chance of survival, the favourable outcome of our patient is probably due to the radical resection of the neoplasm.

[Soft tissue sarcoma in childhood: local treatment in patients under 3 years of age. Analysis of the RMS-88 multicenter study]

The purpose of this report is to describe the treatment and the outcome of patients affected by soft tissue sarcomas and enrolled in the Italian Cooperative Study RMS 88, whose age was less than 36 months. In particular the role of local treatment is discussed, considering that RT was not recommended by the protocol. The 104 patients, 70 affected by RMS and 34 by NR-STS, were grouped according to the Intergroup Rhabdomyosarcoma Staging (IRS) system. The general guidelines of the study for the local treatment included surgery in Gr I, surgery + radiotherapy (40 Gy) in Gr II, surgery (1 or more procedures) + radiotherapy (45-54 Gy) in Gr III, but RT was not recommended for patients < 3 years. RMS: The 5 patients in Gr I did not receive RT: 4/5 are alive NED and 1 is lost at FU. Among the 5 patients in Gr II, 5 did not receive RT and are alive NED; 4 were given RT and 2 of these died of disease. In the 56 patients in Gr III, RT was utilized in 25: 5 died of disease and 6 manifested distant sequelae due to RT. 10/31 patients who were not given RT, did not undergo any other local treatment and died of disease; 4 patients died after surgery only.

NRSTS

7/9 Gr I patients are alive (1 was treated with RT and did not present sequelae); 1/9 died and 1 is lost at FU. 3/6 Gr II patients are alive (1 after RT), 2 died of disease and 1 is lost at FU. 2/19 Gr III patients were given RT and 1 died of disease; 3 of the not irradiated patients died without any local treatment, 4 after surgery only.

CONCLUSION

The local treatment was important for patients' outcome: only 28% of the RMS and 36% of the NRSTS patients who were not treated with surgery a/o RT are in CR. Surgery was not particularly aggressive (6 mutilating procedures). RT was utilized in 33/104 patients and sequelae were 7. The difference in overall survival between patients less than 3 and patients more than 3 is not statistically significant.

Importance of local treatment in pediatric soft tissue sarcomas with microscopic residual after primary surgery: results of the Italian Cooperative Study RMS-88

BACKGROUND

The goal of primary excision in soft tissue sarcomas is the complete removal of the tumor by a nonmutilating procedure. However, microscopic residuals may be left after a conservative procedure because of inadequate preoperative assessment or difficulties during the operation. The purpose of this report is to describe the treatment and the outcome in patients, enrolled in the Italian Cooperative Study RMS-88, with microscopic residuals after primary excision (IRS Group IIa).

PROCEDURE

Microscopic residuals were evident at histology in 52 of 90 patients who had a macroscopic complete primary excision: 25 rhabdomyosarcomas (RMS) and 27 nonrhabdo-soft tissue sarcomas (NRSTS). Eighteen patients were treated with primary reexcision (PRE) and chemotherapy (CT) using VA or IVA regimens; 27 patients received radiation therapy (RT; 40 Gy) and IVA; 7 children in whom PRE was not feasible and RT could not be administered for age <3 years were treated with CT (IVA) alone.

RESULTS

Of the 18 patients who underwent a successful PRE + CT, the local relapses were 3 (16.6%); of 27 cases who had RT + CT there were 4 local relapses (14.8%); 3 local relapses occurred in those 7 patients in whom CT alone was administered (43%).

CONCLUSIONS

Microscopic residuals after primary surgery were difficult to manage because of the absence of a measurable target. PRE represented the treatment of choice for children <3 years of age who cannot receive RT and for paratesticular sites. PRE and RT showed similar results in achieving local control in extremity and trunk sites, but they could not always avoid local recurrence. In particular PRE was not effective in tumors larger than 5 cm. If microscopic residuals could not be avoided and PRE was not possible, adequate RT was effective both for RMS and for NRSTS.

Features and outcome of neuroblastoma detected before birth

BACKGROUND/PURPOSE

The growing use of routine ultrasonography during pregnancy is leading to an increasing number of prenatally diagnosed neuroblastomas. Optimal strategy has not yet been defined for these patients, because knowledge on this particular neuroblastoma (NB) population is still limited. However, definite guidelines are needed to avoid inadequate treatment. The authors analyzed the cases of antenatally detected NB (ADNB) reported in the Italian Neuroblastoma Registry during the past 6 years to elucidate the features of this subset of NB.

METHODS

The Italian Neuroblastoma Registry was reviewed for the period January 1993 to December 1998 to collect clinical, radiographic, surgical, and histopathological data on ADNB cases. NB stage was evaluated according to INSS criteria. All patients had undergone imaging (computed tomography or magnetic resonance imaging) of the primary tumor and bone marrow biopsy before surgical resection.

RESULTS

Seventeen patients were identified. Primary tumour site was adrenal glands in 16 cases and retroperitoneal ganglia in 1. Stage distribution was stage I, 13 cases; stage II-A, 1 case; stage II-B, 1 case; stage IV-S, 2 cases. All cases underwent primary tumour resection. Mean age at surgery was 4 weeks. Resection of primary tumor was radical in 16 cases, partial in 1. All tumors were characterised by favourable histology according to Shimada classification. N-myc gene amplification was studied in 14 patients. N-myc amplification was detected only in a newborn with stage II-A NB, who died of massive bleeding 2 days after tumor resection. DNA index and 1p deletion were studied in 11 and 8 patients, respectively. Both diploidy and deletion of 1p were observed in a newborn who subsequently died of disease progression despite surgery, chemotherapy, and radiation therapy. Fourteen of 17 patients currently are alive and free of disease, and one with IV-S NB and short follow-up is alive with disease.

CONCLUSIONS

Our data give evidence that in most cases infants with ADNB represent a subset of patients with excellent outcome. Aggressive treatment may not always be necessary. Infants with ADNB with unfavorable features should undergo early surgical excision, whereas patients with favourable features could be observed awaiting spontaneous regression of the mass, reserving delayed surgery for tumors that increase in size or do not regress.

Treatment of vesico-ureteric reflux in children with neuropathic bladder: a comparison of surgical and endoscopic correction

BACKGROUND/PURPOSE

Vesico-ureteric reflux (VUR) is a common problem in children with neuropathic bladder. Lesser-degree VUR may be manageable by intermittent catheterization or by anticholinergics, but higher grades usually require surgical treatment. If left untreated, two thirds of such patients may experience deterioration of the upper renal tracts. The aim of this study was to compare the results of the STING (Subureteric Teflon Injection) technique with surgical ureteric reimplantation as treatment for VUR in neuropathic bladder.

METHODS

From January 1981 to December 1996, 58 children with NB (81 ureters) were treated for VUR. STING and Cohen ureteroneocystotomy were performed in 40 and 41 ureters, respectively. Mean age was 4.5 years (STING) and 5.1 years (Cohen).

RESULTS

Twenty-nine of 40 refluxing ureters (72.5%) were cured by STING, whereas Cohen eradicated reflux in 39 of 41 ureters (95.5%). No complications were observed in either group. All the ureters in which STING failed were treated successfully by Cohen ureteroneocystostomy. The 2 ureters still refluxing after surgical reimplantation were cured successfully by a single STING. The mean follow-up was 6.8 years in the Cohen group and 4.8 years in the STING group. During follow-up, no recurrence was observed in patients cured by open reimplantation. In the STING group, 2 previously cured ureters showed recurrence of VUR: both were treated successfully by a further STING.

CONCLUSIONS

Open ureteral reimplantation is more effective than STING in correcting VUR in children with neuropathic bladder dysfunction. Nevertheless, the good success rate, the relative technical simplicity, outpatient nature, and rapid recovery point to STING as a safe and effective procedure for the initial treatment of VUR. Failure of STING does not preclude a successful open operation.

Pancreatitis caused by duodenal duplication

The authors present the investigations and surgical treatment of two cases of duodenal cystic duplication. Abdominal pain and gastroesophageal reflux were the most important symptoms and signs associated with an history of recurrent acute pancreatitis. Computed tomography scan, ultrasound examination, and cholangiography confirmed preoperatively the diagnosis, and a transduodenal surgical approach was carried out in both children. A simple marsupialization of the cyst was performed in the former, and a sphincterotomy with papillosphincteroplasty was associated in the latter. The diagnosis was confirmed by microscopy, and both the children are asymptomatic after a 14 and 18 months of follow-up. This report focuses on the importance of the cholangiopancreatography for every child presenting with recurrent, unexplained bouts of acute pancreatitis, and underlines the technical surgical aspects on the basis of the anatomic identification of the malformation.

Apoptosis and bcl-2 oncogene expression in Wilms' tumor

Wilms' tumor (WT) usually has a good outcome, although a poor prognosis is often related to more advanced stages and anaplastic features. Apoptosis occurs with variable frequency in malignant tumors, and may have a role in reducing their growth rate. The bcl-2 proto-oncogene inhibits apoptosis, and the consequent increase in the number of cells may play a role in the development of tumors. The aim of this study was to analyze the role of apoptosis and bcl-2 expression in WT. Twenty-six resected WT specimens were studied; 12 patients had stage I tumor, 4 stage II, 5 stage III, 3 stage IV, and 2 stage V. Twenty-three tumors were classified as favorable histology (FH) and 3 as unfavorable (UH). The mean follow-up was 34 months; 22 patients were alive and 4 were dead (2 with FH: 1 stage III and 1 stage IV, and 2 with UH stages 4). Apoptosis was detected by the in-situ end-labelling technique; bcl-2 expression was detected by immunohistochemistry. An apoptotic index (AI) was calculated as the ratio of apoptotic to normal cells in each specimen. The AI was lower in higher tumor stages, with a significant difference between stages I and IV (P < 0.05). In cases with UH, Al was lower than in tumors with FH (P < 0.01). The AI was also lower in patients who died than in those who survived (P < 0. 01). In all specimens no correlation between AI and bcl-2 expression was observed. Progression to advanced stages of WT and a poor prognosis f anaplastic tumors may be linked with disruption of the mechanisms that control apoptosis. Bcl-2 does not play a role as a regulator of apoptosis in WT, other oncogenes and tumor-suppression genes may be more involved in inhibiting apoptosis in WT.

Multicenter survey of endoscopic treatment of vesicoureteral reflux using polytetrafluoroethylene

PURPOSE

Endoscopic subureteral polytetrafluoroethylene (Teflon) injection has been used successfully to treat primary and secondary vesicoureteral reflux in children. We review the results of subureteral polytetrafluoroethylene injection in terms of its effectiveness, long-term followup and morbidity.

MATERIALS AND METHODS

A total of 53 pediatric urologists and/or pediatric surgeons at 41 centers worldwide answered an inquiry regarding experience with subureteral polytetrafluoroethylene injection in vesicoureteral reflux. Data were collected from a completed standard questionnaire. From 1984 to 1996, 1,921 boys and 6,411 girls with a mean age of 4.5 years (12,251 refluxing ureters) were treated endoscopically with subureteral polytetrafluoroethylene injection. Reflux was grades I to V in 407 (3.3%), 3,832 (31.2%), 5,213 (42.5%), 2,218 (18.1%) and 581 (4.7%) ureters, respectively. In the majority of patients subureteral polytetrafluoroethylene injection was performed on an outpatient basis. Most urologists monitored patients with voiding cystourethrography and renal ultrasound at 3 months, 1 year and 3 years. All patients were followed 1 to 13 years.

RESULTS

Reflux resolved in 9,226 ureters (75.3%) after 1 polytetrafluoroethylene injection, in 1,478 (12%) after 2 and in 250 (2%) after 3 or 4. Vesicoureteral reflux improved to grade I after 1 or 2 injections in 743 (6%) ureters, which needed no further treatment. Subureteral injection failed to correct reflux in 554 ureters (4.5%), which were then treated with ureteral reimplantation. Vesicoureteral junction obstruction requiring ureteral reimplantation developed in 41 ureters (0.33%). More than 90% of patients have been followed for more than 2 years. At followup reflux recurred in 326 (2.8%) endoscopically corrected refluxing ureters. No clinically untoward effects were reported in any patient due to the use of polytetrafluoroethylene as an injectable material.

CONCLUSIONS

The results of this multicenter survey confirm that endoscopic subureteral polytetrafluoroethylene injection is a simple, safe and effective outpatient procedure for treating all grades of vesicoureteral reflux.