Design of a magnetic localisation system for in-vivo endovascular interventions

Endovascular catheterisation is performed by an interventional radiologist using fluoroscopic guide and contrast-media. The X-Ray exposure both of the patient and of the operators can induce heavy collateral effects. The present paper describes an innovative magnetic position/orientation indicator capable to drive the endovascular probe during in-vivo medical diagnostic or interventional procedures. It uses the magnetic field produced by a thin permanent magnet installed on the endovascular probe and magnetic field sensors positioned outside the patient body: this allow the elimination of repetitive X-Ray scans used to monitor the probe position. The aims of the proposed system are: to drive the catheter inside the patient vascular tree with a reduction of the X-Ray exposure both of the patient and of the personnel involved in the intervention; to allow a more comfortable operative condition for the personnel due to the reduction of the time they wear X-Ray protective systems. The paper reports the mathematical problem formulation, the numerical simulations for the magnetic field calculation produced by the thin endovascular permanent magnet and the system design of the usable hardware.

Spinodal of supercooled polarizable water

We develop a series of molecular dynamics computer simulations of liquid water, performed with a polarizable potential model, to calculate the spinodal line and the curve of maximum density inside the metastable supercooled region. After analyzing the structural properties, the liquid spinodal line is followed down to T=210K . A monotonic decrease is found in the explored region. The curve of maximum density bends on approaching the spinodal line. These results, in agreement with similar studies on nonpolarizable models of water, are consistent with the existence of a second critical point for water.

Intrathecal IgM production at clinical onset correlates with a more severe disease course in multiple sclerosis

The intrathecal synthesis of IgM, determined at clinical onset in patients with multiple sclerosis, was found to correlate with the degree of disability (as evaluated by means of the Expanded Disability Status Scale) reached 15 years later (p<0.001). Moreover, a significant inverse correlation was observed between the value of the IgM index and time to the first relapse (p<0.001) and the initiation of the progressive phase of the disease (p = 0.01). The prognostic value of IgM in the CSF is confirmed in previous reports as well as by our study. If these findings are confirmed in patients with multiple sclerosis in a larger series, a helpful biological marker for selecting patients for immunomodulatory treatments will be available to neurologists.

Knowledge and attitudes regarding preventative HIV vaccine clinical trials in Italy: results of a national survey

We carried out a telephone survey to assess willingness to participate in HIV vaccine trials. The survey was conducted by interviewing randomly selected callers to the Italian National AIDS Help line. The questionnaire consisted of four sections: demographic information, knowledge about HIV vaccines and vaccines in general, factors related to participation in HIV vaccine trials, and acceptability of a future HIV vaccine. Over 50% of the sample had adequate knowledge about HIV and vaccines. Among the individuals interviewed, 37% would volunteer for a vaccine trial; those reporting high-risk behaviours were more likely to volunteer. Of the participants, 83% would agree to be vaccinated with a highly effective vaccine, and 92% would pay for the vaccine. Although the limits of telephone surveys should not be neglected, the results of this survey are encouraging.

Adenovirus as vehicle for anticancer genetic immunotherapy

Adenoviruses (Ads) are in the forefront of genetic immunization methods being developed against cancer. Their ability to elicit an effective immune response against tumor-associated antigens has been demonstrated in many model systems. Several clinical trials, which use Ad as vehicle for immunization, are already in progress. Preclinical studies have also demonstrated the efficacy of combining Ad-mediated immunization with adjuvants such as chemotherapeutic agents and cytokines. Issues related to sero-prevalence and safety of Ads, however, continue to pose a challenge and need to be addressed.

Immunological markers in multiple sclerosis: tackling the missing elements

Multiple sclerosis (MS) is a complex disease in which several pathophysiological mechanisms are involved: inflammation, demyelination, axonal damage and repairing. Further complicating the picture, such processes are variably represented in MS patient populations, thus accounting for the heterogeneity in phenotypic expression of the disease, its prognosis and response to therapies. In the last decade a huge effort has been made in the attempt to "capture" the gold fish, i. e., biological markers either specific for the disease and/or capable to predict, in newly diagnosed MS patients, disease course and response to therapy. Moreover, these biomarkers would be extremely useful in the development of new process-specific therapies. Unfortunately such markers are far from being "fished", but recent studies have pointed out new interesting candidates, driving new energies and hopes in the MS research community. In this review we briefly discuss the latest news on immune markers in MS.

Inherent structures and Kauzmann temperature of confined liquids

Calculations of the thermodynamical properties of a supercooled liquid confined in a matrix are performed with an inherent structure analysis. The liquid entropy is computed by means of a thermodynamical integration procedure. The contributions to the free energy of the liquid can be decoupled also in confinement in the configurational and the vibrational parts. We show that the vibrational entropy can be calculated in the harmonic approximation as in the bulk case. The Kauzmann temperature of the confined system is estimated from the behavior of the configurational entropy.

Computer simulation of the phase diagram for a fluid confined in a fractal and disordered porous material

We present a grand canonical Monte Carlo simulation study of the phase diagram of a Lennard-Jones fluid adsorbed in a fractal and highly porous aerogel. The gel environment is generated from an off-lattice diffusion limited cluster-cluster aggregation process. Simulations have been performed with the multicanonical ensemble sampling technique. The biased sampling function has been obtained by histogram reweighting calculations. Comparing the confined and the bulk system liquid-vapor coexistence curves we observe a decrease of both the critical temperature and density in qualitative agreement with experiments and other Monte Carlo studies on Lennard-Jones fluids confined in random matrices of spheres. At variance with these numerical studies we do not observe upon confinement a peak on the liquid side of the coexistence curve associated with a liquid-liquid phase coexistence. In our case only a shouldering of the coexistence curve appears upon confinement. This shoulder can be associated with high density fluctuations in the liquid phase. The coexisting vapor and liquid phases in our system show a high degree of spatial disorder and inhomogeneity.

A double blind, placebo-controlled, phase II, add-on study of cyclophosphamide (CTX) for 24 months in patients affected by multiple sclerosis on a background therapy with interferon-beta study denomination: CYCLIN

The authors present and discuss a new protocol for active multiple sclerosis (MS) patients. A double blind randomized controlled multicenter study was planned to study the effects of a combination regimen therapy: cyclophosphamide plus beta interferon versus beta interferon alone on both relapsing-remitting and secondary MS patients with active disease. The primary endpoint of this study is the number of new gadolinium enhancing lesions at MRI evaluation. Secondary endpoints are new T2 lesions, new T1 lesions, T2 lesion load, T1 lesion load, cerebral atrophy, number of patients who were relapse-free, number of patients who improved, yearly relapses, quality of life, disability and cognitive impairment, frequency of neutralizing antibodies, safety of the combination therapy (cyclophosphamide + beta interferon). The study will enroll 225 patients in 25 Italian MS centers. Eligible for the study are patients with either relapsing-remitting or secondary MS according McDonald criteria on 6-24 months beta interferon treatment with active disease (new gadolinium enhancing lesion or who experienced a new relapse on beta interferon treatment). Clinical evaluation will be performed every 4 months, MRI yearly. Vital signs and eventual adverse events will be collected monthly. The study will last 36 months, 12 for the enrollment phase and 24 for the treatment phase. The study will start on April 2004.

Slow dynamics of a confined supercooled binary mixture. II. Q space analysis

We report the analysis in the wave vector space of the density correlator of a Lennard-Jones binary mixture confined in a disordered matrix of soft spheres upon supercooling. In spite of the strong confining medium the behavior of the mixture is consistent with the mode-coupling theory predictions for bulk supercooled liquids. The relaxation times extracted from the fit of the density correlator to the stretched exponential function follow a unique power law behavior as a function of wave vector and temperature. The von Schweidler scaling properties are valid for an extended wave vector range around the peak of the structure factor. The parameters extracted in the present work are compared with the bulk values obtained in literature.

Effects of confinement on static and dynamical properties of water

Molecular-dynamics results on water confined in a silica pore are reviewed and discussed in connection with experiments performed on water in Vycor and with studies of water in contact with proteins. The properties of confined water are studied as a function of both temperature and hydration level. The interaction of water in the film close to the substrate with the silica atoms induces a strong distortion of the hydrogen bond network. At high hydration levels a double dynamical regime is observed. At low hydration an anomalous diffusion is found upon supercooling with a transition from a Brownian to a non-Brownian regime on approaching the substrate in agreement with results found in studies of water in contact with globular proteins.

Increasing frequency of multiple sclerosis in Padova, Italy: a 30 year epidemiological survey

OBJECTIVE

To determine the incidence and prevalence rates of multiple sclerosis (MS) and their temporal profiles over the last 30 years in the province of Padova (northeast Italy).

BACKGROUND

In the early 1970s an epidemiological survey in the province of Padova showed a MS prevalence and incidence of 16/100 000 and 0.9/100 000 population, respectively; these figures are much lower than current estimates in other regions of Italy and Central Europe.

METHODS

The population of the study area was approximately 820 000 (422 028 women, 398 290 men) in the 1991 census. All possible sources of case collection were used, but only clinically definite/probable and laboratory-supported definite/probable MS were considered in the analysis of incidence and prevalence trends from 1971 to 1999.

RESULTS

On 31 December 1999, the crude prevalence rate was 80.5/100 000 (95% CI 70.3-90.7); prevalence was higher in women (111.1/100 000; 95% CI 99.0-123.1) than in men (49.7/100 000; 95% CI 41.3-58.1). This difference was significant (F/M = 2.43; z = 10.1, P < 0,00001); a rate adjusted for the European population was 81.4/100 000. On 31 December 1980 and on 31 December 1990 the estimated prevalence rates were 18/100 000 and 45.7/100 000, respectively. Thus, a fivefold increase in prevalence was observed from the 1970s. The mean annual incidence was 2.2/100 000 in the period 1980-89, 3.9 in the period 1990-94 and 4.2 in the period 1995 99. Thus, incidence increased more than fourfold from the 1970s through 1994 and remained quite stable in the last several years. Mean age at onset was 31.3 +/- 9.88 years. Mean diagnostic latency decreased significantly from 49.2 +/- 44.5 months in 1985 to 23.0 +/- 30.3 months in 1990, 12.9 +/- 15.61 in 1995 and 5.3 +/- 4.7 in 1999.

CONCLUSIONS

The actual prevalence (80.5/100 000) and incidence (4.2/100 000) of MS in the province of Padova agree with the most recent epidemiological estimates/trends observed in other Italian and European areas, except for Sardinia and Scotland. The increase in both incidence and prevalence rates observed in much of this region over the last 30 years parallels the introduction of more sensitive diagnostic techniques and a highly significant decrease in diagnostic latency. These findings probably do not support a real increase in the frequency of MS in northeast Italy because recent estimates of incidence have increased only slightly (3.9 to 4.2, which is < 10% in five years) and increase in the prevalence rate was almost completely due to the accumulation of new incidence cases.

Growth hormone secretion in polytransfused prepubertal patients with homozygous beta-thalassemia. Effect of long-term recombinant GH (recGH) therapy

Growth was monitored in 133 male and 150 female North Sardinian prepubertal patients with homozygous beta-thalassemia in order to ascertain the incidence of GH deficiency (GHD) and the effects of long-term recombinant GH (recGH) treatment on growth velocity and bone maturation. A significant reduction in growth velocity and a fall in IGF-I levels was observed in 19 male and 16 female patients (12.3%). Their peak GH responses to GHRH (5.45+/-0.78 and 4.99+/-0.86 ng/ml) and clonidine administration (4.21+/-0.32 and 4.15+/-0.27 ng/ml in males and females, respectively) were markedly reduced with respect to control subjects (p<0.01). No statistically significant correlation was found between chronological age, number of blood units received, plasma ferritin levels and plasma IGF-I levels as well as with peak GH response to stimulation. Thalassemic patients with GHD had plasma ferritin levels (1382.44+/-160.34 and 1255.23+/-139.81 ng/ml in males and females, respectively) significantly lower than those recorded in the other patients (2848.94+/-283.61 and 3077.82+/-220.51 ng/ml). Patients with GHD were treated with recGH for an average period of 59 months (range 26-124). Treatment was able to restore growth and to increase significantly plasma IGF-I levels. Growth velocity at the end of the first yr of treatment was 6.78+/-1.21 and 6.11+/-0.85 cm/yr in males and females, respectively. Growth velocity values and plasma IGF-I levels remained significantly higher than basal values throughout the period of treatment. However, treatment was unable to normalize bone maturation since bone age values were always reduced with respect to chronological age. No incidence of side effects was observed. These data indicate that GHD, when present, is one but not the sole cause of delayed bone maturation and height deficiency in thalassemia.

Slow dynamics of a confined supercooled binary mixture: direct space analysis

Dynamical properties of a Lennard-Jones binary mixture embedded in an off-lattice matrix of soft spheres are studied in the direct space upon supercooling by molecular dynamics simulations. On lowering the temperature, the smaller particles tend to avoid the soft sphere interfaces and correspondingly their mobility decreases below one of the larger particles. The system displays a dynamic behavior, consistent with the mode coupling predictions. A decrease in the mode coupling crossover temperature with respect to the bulk is found. We however find that the range of validity of the theory shrinks with respect to the bulk. This is due to the change in the smaller particle mobility and to a substantial enhancement of hopping processes well above the crossover temperature upon confinement.

Microscopic two-dimensional lattice model of dimer granular compaction with friction

We study by Monte Carlo simulation the compaction dynamics of hard dimers in two dimensions under the action of gravity, subjected to vertical and horizontal shaking, considering also the case in which a friction force acts for horizontal displacements of the dimers. These forces are modeled by introducing effective probabilities for all kinds of moves of the particles. We analyze the dynamics for different values of the time tau during which the shaking is applied to the system and for different intensities of the forces. It turns out that the density evolution in time follows a stretched exponential behavior if tau is not very large, while a power law tail develops for larger values of tau. Moreover, in the absence of friction, a critical value tau(*) exists, which signals the crossover between two different regimes: for tau<tau(*) the asymptotic density scales with a power law of tau, while for tau>tau(*) it reaches logarithmically a maximal saturation value. Such behavior smears out when a finite friction force is present. In this situation the dynamics is slower and lower asymptotic densities are attained. In particular, for significant friction forces, the final density decreases linearly with the friction coefficient. We also compare the frictionless single tap dynamics to the sequential tapping dynamics, observing in the latter case an inverse logarithmic behavior of the density evolution, as found in the experiments.