Geometrical Characterization of an Electropore from Water Positional Fluctuations.

We present here a new method for calculating the radius of a transmembrane pore in a phospholipid bilayer. To compare size-related properties of pores in bilayers of various compositions, generated and maintained under different physical and chemical conditions, reference metrics are needed. Operational metrics can be associated with some observed behavior. For example, pore size can be defined by the largest object that will pass through the length of the pore. The novelty of the present approach resides in the characterization of electropore geometry via a statistical approach, based on essential dynamics rules. We define the pore size geometrically with an algorithm for determining the pore radius. In particular, we extract the radius from the tri-dimensional surface of a defined pore region. The method is applied to a pore formed in a phospholipid bilayer by application of an external electric field. Although the details described here are specific for lipid pores in molecular dynamics simulations, the method can be generalized for any kind of pores for which appropriate structural information is available.

Electroporation Mechanisms: The Role of Lipid Orientation in the Kinetics of Pore Formation.

Electroporation is a well-established technique used to stimulate cells, enhancing membrane permeability. Although the biological phenomena occurring after the poration process have been widely studied, the physical mechanisms of pore formation are not clearly understood. In this work we investigated by means of molecular dynamics simulations the kinetics of pore formation, linking the different stages of poration to specific arrangements of lipid membrane domains.Clinical Relevance-The approach followed in this study aims to shed light on the molecular mechanisms at the basis of the electroporation technique, nowadays used to enhance the entrance of poorly permeant anticancer drugs into tumor cells, for gene electrotransfer and all the other applications exploiting the modulation of cell membrane properties.

Microdosimetric Realistic Model of a Cell with Endoplasmic Reticulum.

When investigating the biophysical effects induced by the interaction between electromagnetic fields and biological cells, it is crucial to estimate the electromagnetic field intensity at the microscopic scale (microdosimetry). This information allows to find a connection between the external applied field and the observed biological event required to establish related biomedical applications. Here, authors present a microdosimetric study based on a 2D realistic model of a cell and its endoplasmic reticulum. The microdosimetric analysis of the cell and endoplasmic reticulum was quantified in terms of electric field and transmembrane potential induced by an externally applied high amplitude 10-ns pulsed electric field. In addition, electroporated local membrane sites and pore densities were also evaluated. This study opens the way to numerically assist experimental applications of nanosecond pulsed electric fields for controlled bio-manipulation of cells and subcellular organelles.

Comparison between low-level 50 Hz and 900 MHz electromagnetic stimulation on single channel ionic currents and on firing frequency in dorsal root ganglion isolated neurons.

Alteration of membrane surface charges represents one of the most interesting effects of the electromagnetic exposure on biological structures. Some evidence exists in the case of extremely low frequency whereas the same effect in the radiofrequency range has not been detected. Changes in transmembrane voltages are probably responsible for the mobilization of intracellular calcium described in some previous studies but not confirmed in others. These controversial results may be due to the cell type under examination and/or to the permeability properties of the membranes. According to such a hypothesis, calcium oscillations would be a secondary effect due to the induced change in the membrane voltage and thus dependent on the characteristics of ionic channels present in a particular preparation. Calcium increases could suggest more than one mechanism to explain the biological effects of exposure due to the fact that all the cellular pathways using calcium ions as a second messenger could be, in theory, disturbed by the electromagnetic field exposure. In the present work, we investigate the early phase of the signal transmission in the peripheral nervous system. We present evidence that the firing rate of rat sensory neurons can be modified by 50/60 Hz magnetic field but not by low level 900 MHz fields. The action of the 50/60 Hz magnetic field is biphasic. At first, the number of action potentials increases in time. Following this early phase, the firing rate decreases more rapidly than in control conditions. The explanation can be found at the single-channel level. Dynamic action current recordings in dorsal root ganglion neurons acutely exposed to the electromagnetic field show increased functionality of calcium channels. In parallel, a calcium-activated potassium channel is able to increase its mean open time.

Monopole patch antenna for in vivo exposure to nanosecond pulsed electric fields.

To explore the promising therapeutic applications of short nanosecond electric pulses, in vitro and in vivo experiments are highly required. In this paper, an exposure system based on monopole patch antenna is reported to perform in vivo experiments on newborn mice with both monopolar and bipolar nanosecond signals. Analytical design and numerical simulations of the antenna in air were carried out as well as experimental characterizations in term of scattering parameter (S 11) and spatial electric field distribution. Numerical dosimetry of the setup with four newborn mice properly placed in proximity of the antenna patch was carried out, exploiting a matching technique to decrease the reflections due to dielectric discontinuities (i.e., from air to mouse tissues). Such technique consists in the use of a matching dielectric box with dielectric permittivity similar to those of the mice. The average computed electric field inside single mice was homogeneous (better than 68 %) with an efficiency higher than 20 V m-1 V-1 for the four exposed mice. These results demonstrate the possibility of a multiple (four) exposure of small animals to short nanosecond pulses (both monopolar and bipolar) in a controlled and efficient way.

Microchambers for cell exposure: from the design to applications.

In the last decades, the advances in the micro and nano fabrication techniques have led to the development of microdevices that improved the possibility of analysis at cell level. These devices can be used in different applications (e.g., cell detection and identification, manipulation, cell treatments). The requisites, that are necessary to achieve, are different for various applications and represent the starting point of the project. The numerical multiphysics models can be very advantageous to analyze the performances of such devices and to predict their operation. Aim of this work is to give a look of the design rules of microchamber devices in particular for their application in electric field exposure. Two different applications for cell discrimination and characterization are reported considering time and frequency domain measurements.

A microdosimetry study for a realistic shaped nucleus.

In the last decades, the effects of ultrashort pulsed electric fields have been investigated demonstrating their capability to be involved in a great number of medical applications (e.g. cancer, gene electrotransfer, drug delivery, electrofusion). In particular, experiments in literature demonstrate that internal structures can be involved when pulse duration is reduced. Up to now, the mechanism that permits the electroporation phenomenon has not been completely understood and hence atomistic, microdosimetry and dosimetry models have been developed to help in this field. Aim of this work is to demonstrate the importance of realistically model also the internal organelles to obtain predictive results of effects at sub-cellular level with a microdosimetry model.

Scenarios approach to the electromagnetic exposure: the case study of a train compartment.

Previous studies identified the train compartment as the place where people can experience the highest exposure levels (still below the international guideline limits) to electromagnetic fields in the radiofrequency range. Here a possible scenario of a train compartment has been reproduced and characterized, both numerically and experimentally. A good agreement between the simulated electric field distributions and measurements has been found. Results indicate that the higher values of exposure in specific positions inside the train compartment depend on the number of active cell phones, the bad coverage condition, the cell orientation, and the presence of metallic walls. This study shows that the proposed approach, based on the scenarios characterization, may efficiently support the assessment of the individual electromagnetic exposure.

Ultrasound and computed tomography in staging of bladder tumours.

Eighty-seven patients with proven bladder tumours were retrospectively reviewed with ultrasound (US) and computed tomography (CT), in order to define the stage of the neoplasm. The tumours were divided into three groups with respect to the TNM classification system. Results indicate that US could predict an exact staging of the bladder tumours in 80.6% of cases in the first group (P1), 68.9% of cases in the second group (P2 - P3), and 90.0% of cases in the third group (P4). CT could predict an exact staging in 61.3% of the bladder tumours in the first group, 91.1% in the second group, and 90.0% in the third group. This finding suggests that the capability of US in detecting bladder tumours in stage P1 may avoid the use of CT, while in subsequent stages CT becomes valuable for the evaluation of extravesical invasions and lymph node metastasis.

[Renal cholesteatoma]. / Colesteatoma renale.

Renal cholesteatoma is an extremely uncommon disease. The renal pelvis is the most common site, but the lesion can be localized, even if rarely, in a calix or in the ureter. Histologically it consists of a keratinizing desquamative squamous metaplasia, with absence of cellular atypia in the urothelium, therefore cholesteatoma is not considered as a premalignant lesion. Authors report a case of renal cholesteatoma and take into consideration particularly the question regarding the diagnostic approach, that in spite of the help of new imaging techniques, as TC, is unable to arrive at a certain diagnosis, and the therapeutic approach, that must be conservative, when it's possible and according to the majority of Authors.

[Stage P-1 primary neoplasia of the bladder. Critical evaluation of results obtained with the use of adriamycin and mitomycin C in the prevention of recurrences]. / Neoplasie primitive della vescica allo stadio P1. Valutazione critica dei risultati ottenuti con l'impiego dell'adriamicina e della mitomicina C nella profilassi delle recidive.

However adequately treated, surface carcinomas of the bladder recur sooner or later with infiltration found in about 10% of cases. Any development that may offer therapeutic progress and reduce the incidence of recurrences is therefore of primary importance. Two homogeneous groups of patients were selected for the present study: 35 were given Adriamycin and 25 Mitomycin C. In evaluating results, the incidence of recurrences in relation to the primary neoplasia and the existence of single or multiple tumors was analysed. It is concluded that Mitomycin C in association with either T.U.R. or T.V.R. is a particularly useful and indubitably effective form of topical chemotherapy in cases of single or multiple primary neoplasias.

[Normal values of the urinary activity of 4 enzymes]. / I valori normali dell'attività urinaria di 4 enzimi.

The urinary activity of 4 enzymes (NAG, GLU, GAL, GRS) was investigated in 105 healthy subjects in order to evaluate the variability of standard levels and establish the degree of such variations in relation to sex, age, weight and height. The results obtained demonstrate that these enzymurias do vary in relation to the parameters examined. Age and sex produced the most pronounced variations though height and body weight also appeared to have some influence. The study of variations in standard levels is of value in the interpretation of pathological enzymurias.

[Behavior of certain forms of enzymuria in subjects treated with pipemidic acid]. / Considerazioni sul comportamento di alcune enzimurie in soggetti trattati con acido pipemidico.

Three groups of subjects (I with infections of the lower urinary ways; II with chronic pyelonephritis; III healthy controls) were treated with pipemidic acid for 10 consecutive days and the behaviour of their urinary NAG and AAP was studied. It was discovered that the healthy group and the patients with infections of the lower urinary ways showed no significant variations in the urinary activity of the two enzymes following the administration of pipemidic acid. However there was a distinct reduction in both enzymes in patients with chronic pyelonephritis who presented demonstrable bacterial sensitivity to the drug. Apart from the fact that it produces no nephrotoxic effects at least in the doses used and for the treatment period adopted, the drug is therefore considered to reduce renal inflammation that is beneficial to individuals with chronic interstitial nephropathy.

[Partial and multiple correlations between 4 types of enzymuria in 2 groups of chronic nephropathic patients]. / Aspetti di correlazione parziale e multipla tra quattro enzimurie in due gruppi di nefropatici cronici.

The urinary activity of four enzymes (NAG, GLU, GRS and GAL) was studied in two groups of patients suffering respectively from interstitial nephritis and chronic glomerulonephritis with the aim of further investigating enzyme variability through the theory of partial and multiple correlation. This study permitted the effects of two enzymes on the known correlations between the remaining two enzyme types to be studied. It was established that very stable relationships exist between each enzyme and the group composed of the remaining three. In particular, in patients with interstizial nephritis, correlations with GAL were all highly significant even if the effect of the other two enzymes was ignored. Similarly, correlations with GRS were strongly significant in patients with chronic glomerulonephritis. In the two groups studied, each enzyme appears to have a highly stable relationship with the other three. Accurate estimates may probably be achieved for GAL and GRS in both groups and for NAG in the glomerulonephritis sufferers. This is further evidence that the enzyme procedure may be used to differentiate between interstitial and glomerular nephritis.

[Radiologic staging after surgical, chemical, and radiation treatment of non-seminomatous tumors of the testis]. / La stadiazione radiologica dopo trattamento chirurgico, chemio e radioterapico dei tumori non seminomatosi del testicolo.

The aim of this work was to evaluate the clinic usefulness of Computed Tomography (CT) and Magnetic Resonance (RM) in the staging after surgery, radiotherapy and chemotherapy of the nonseminomatous germ cells tumours of the testis. The Authors discussed the CT and MR dimensional criteria for the diagnosis of retroperitoneal metastases of the nonseminomatous germ cells tumours and delineated their CT and MR morphologic appearances in detail. The density of the residual mass on CT was classified as solid, cystic and half-cystic. The retroperitoneal hematoma and lymphocele formed as a complication respectively of orchiectomy and retroperitoneal lymphadenectomy can be misinterpreted to represent metastatic disease on post operative staging CT scans. Early recognition of this complication are crucial if unnecessary treatment is to be avoided. Finally the Authors evaluated, in patients affected from nonseminomatous germ cells tumours of the testis, the possibility to characterize with CT and MR imaging the retroperitoneal mass. The density and character of the residual mass on CT scan did not reliably predict the histology. On the basis of tumor consistency and signal intensity in T1 and T2 weighted images, MR cannot yet warrant any conclusion about the ultimate effect of chemotherapy.

[Surgical treatment of unrepairable vesicovaginal fistulas]. / La terapia chirurgica delle fistole vescico-vaginali non riparabili.

The authors discuss different types of urinary diversion as the therapy of unrepairable vesico-vaginal fistulas. They also describe the therapy performed in their experience and underline that, at the moment, rectal bladder is to be considered the best solution.

[A case of epidermoid cyst of the testis]. / Un caso di cisti epidermoide del testicolo.

The epidermoid cyst of the testis represents about 1% of all testicle tumours. The average age of presentation ranges from the second and the fourth decade of life. Its clinical features do not differ from those of a testis malignancy. Preliminary clinical and laboratory findings do not determine the diagnosis. The Authors report a case and review the Literature (about 150 cases up to 1985). Therapeutic strategy is also discussed: orchiectomy or simple removal of the cyst.

A molecular dynamic study of cholesterol rich lipid membranes: comparison of electroporation protocols.

We report on a molecular dynamics (MD) simulation study of the electroporation of lipid bilayers at different cholesterol contents using protocols mimicking "traditional" electroporation, i.e. low intensity millisecond pulses (msEP), and high intensity nanosecond electric pulses (nsEP). The results show that addition of cholesterol in concentrations of lipid:sterol ranging from 20 to 50 mol% enhances substantially the membrane cohesion, which is manifested by an increase of the electroporation threshold (U(thr)). This increase is steady in the case of the nsEP protocol, reaching roughly a factor 2 in the 50 mol% samples. In contrast, for the msEP protocol, U(thr) increases by 50% upon addition of 30 mol% cholesterol then levels off. Furthermore, pores formed under msEP are found to possess morphologies much different from the usually reported hydrophilic "electropores" encountered under the nsEP protocol, which may have profound consequences on the transport properties of "electroporated" membranes. Hence, this study reveals that cell membrane models containing the ubiquitous cholesterol component respond quite differently to the two electroporation techniques, in contrast to what has been found for simple zwitterionic bilayers.

[Epidemiology of CKD in Italy and prevention strategies]. / Epidemiologia della malattia renale cronica in italia e strategie per la prevenzione.

Although chronic kidney disease (CKD) is a major health problem worldwide; it is not adequately considered in the strategies for the prevention of non-communicable diseases. To plan properly preventive strategies in our country, we need to know what is the prevalence of CKD, the risk factors, the level of awareness for the diagnosis, the referral to specialists nephrologists and the prognosis of patients followed in primary care. The prevalence of CKD, adjusted for age and gender, is 6.3% and the major independent risk factors are represented by old age, arterial hypertension, obesity, diabetes, cardiovascular disease and smoking . The awareness of the diagnosis in our country in 2003 is underestimated and nephrology referral for individuals with glomerular filtration (GF) under 60 ml / min was only 10%. The prognosis of patients, followed exclusively in primary care, worsens progressively for values of GF under 45 ml / min, both as need for substitutive treatment and mortality, compared with patients of stage I and II. To improve the management of CKD, it would be useful to set up an electronic database on our national territory by a network among laboratories, primary care, and nephrologists. An example of this organization is Great Britain that evidences encouraging results in the treatment and prevention of this debilitating disease.

A numerical study to compare stimulations by intraoperative microelectrodes and chronic macroelectrodes in the DBS technique.

Deep brain stimulation is a clinical technique for the treatment of parkinson's disease based on the electric stimulation, through an implanted electrode, of specific basal ganglia in the brain. To identify the correct target of stimulation and to choose the optimal parameters for the stimulating signal, intraoperative microelectrodes are generally used. However, when they are replaced with the chronic macroelectrode, the effect of the stimulation is often very different. Here, we used numerical simulations to predict the stimulation of neuronal fibers induced by microelectrodes and macroelectrodes placed in different positions with respect to each other. Results indicate that comparable stimulations can be obtained if the chronic macroelectrode is correctly positioned with the same electric center of the intraoperative microelectrode. Otherwise, some groups of fibers may experience a completely different electric stimulation.