S Di Luzio

Infrared functional imaging applied to Raynaud's phenomenon

Presents an approach that allows simultaneous assessment of thermal properties of multiple fingers on both hands. It is a novel approach to the estimation of Raynauds phenomenon based on infrared functional imaging assessments. Q, which represents the total amount of stored heat by the finger during the rewarming processes and is evaluated by means of the area under the time-temperature curve, seems to be particularly effective in order to describe the thermal recovery capabilities of the finger, also in terms of thermal efficiency. Q clearly highlights the difference between primary Raynauds phenomenon and secondary scleroderma patients, and between patients and normal as well, and provides useful information about the abnormalities of their thermoregulatory finger properties.

Time course reconstruction of fetal cardiac signals from fMCG: independent component analysis versus adaptive maternal beat subtraction.

M-mode and pulsed Doppler echocardiography, cardiotocography and transabdominal fetal ECG are available in clinical practice to monitor fetal cardiac activity during advancing gestation, but none of these methods allows the direct measurement of morphological and temporal parameters for fetal rhythm assessment. Fetal magnetocardiograms (fMCGs) are noninvasive recordings of magnetic field variations associated with electrical activity of the fetal heart obtained with superconducting sensors positioned over the maternal abdomen inside a shielded room. Because of maternal cardiac activity, fMCGs are contaminated by maternal components that need to be eliminated to reconstruct fetal cardiac traces. The aim of the present work was to use two methods working in the time domain, an independent component analysis algorithm (FastICA) and an adaptive maternal beat subtraction technique (AMBS), for the retrieval of fetal cardiac signals from fMCGs. Detection rates of both methods were calculated, and FastICA and AMBS performances were compared in the context of clinical applications by estimating several temporal and morphological characteristics of the retrieved fetal traces, such as the shape and duration P-QRS-T waves, arrhythmic beat detection and classification, and noise reduction. Quantitative and qualitative comparison produced figures that always suggested that FastICA was superior to AMBS from the perspective of clinical use of the recovered fetal signals.

Fetal magnetocardiographic mapping using independent component analysis

Fetal magnetocardiography (fMCG) is the only noninvasive technique allowing effective assessment of fetal cardiac electrical activity during the prenatal period. The reconstruction of reliable magnetic field mapping associated with fetal heart activity would allow three-dimensional source localization. The efficiency of independent component analysis (ICA) in restoring reliable fetal traces from multichannel fMCG has already been demonstrated. In this paper, we describe a method of reconstructing a complete set of fetal signals hidden in multichannel fMCG preserving their correct spatial distribution, waveform, polarity and amplitude. Fetal independent components, retrieved with an ICA algorithm (FastICA), were interpolated (fICI method) using information gathered during FastICA iterations. The restored fetal signals were used to reconstruct accurate magnetic mapping for every millisecond during the average beat. The procedure was validated on fMCG recorded from the 22nd gestational week onward with a multichannel MCG system working in a shielded room. The interpolated traces were compared with those obtained with a standard technique, and the consistency of fetal mapping was checked evaluating source localizations relative to fetal echocardiographic information. Good magnetic field distributions during the P-QRS-T waves were attained with fICI for all gestational periods; their reliability was confirmed by three-dimensional source localizations.

Quantifying the relevance and stage of disease with the Tau image technique

Discusses a complementary diagnostic imaging technique based on infrared functional imaging. It is concluded that the Tau images obtained with our method provide a large amount of information. The method, in fact, correctly depicts the ill and symptomatic situation; moreover, it is able to identify the surface projection onto the skin of the damaged areas and, by means of the evaluated value of the Tau time, the stage of the disease. Additionally, it is possible to evaluate the evolution of the clinical situation following a rehabilitation therapy and to quantitatively compare the different Tau images recorded at different times.

A biomagnetic method for studying gastro-intestinal activity

SummaryA novel method to investigate the gastro-intestinal activity by means of a superconducting instrumentation based on SQUID sensors developed for biomagnetic measurements is presented. The magnetic field generated by a small marker ingested by the subject is measured over the abdomen. The localization of the marker, i.e. a magnetic dipole, is carried out by means of a standard algorithm used in biomagnetic studies. In this way it is possible to noninvasively study the activity of the gastro-intestinal system. This new approach may lead to important clinical applications.

Biological Effects of Electromagnetic Fields

Nowadays, concerns about hazards from electromagnetic fields represent an alarming source for human lives in technologically developed countries. We are surrounded by electromagnetic fields everywhere we spend our working hours, rest or recreational activities. The aim of this review is to summarize the biological effects due to these fields arising from power and transmission lines, electrical cable splices, electronic devices inside our homes and work-places, distribution networks and associated devices such as cellular telephones and wireless communication tower, etc. Special care has been reserved to study the biological effects of electromagnetic fields on cell lines of the mammalian immune system about which our research group has been working for several years.Molecular biology today appears to be the mainstream interpretative basis for all cellular and pathophysiological phenomena, even going so far as to embrace neuronal and psychic events. The explanation of disease processes, whether genetic or acquired, is sought and, where possible, located in mechanisms consisting in quantitative and/or qualitative modifications of particular molecules making up part of the various anatomical or physiological systems. In relation with the molecular paradigm of disease, also the medical treatment is today founded mostly on the conventional pharmacological approach. However, the need of further research in different fields is suggested by the fact that biological phenomena are characterized by high levels of organization, in which inter-molecular and inter-cellular communications of biophysical nature appear to be involved according to many lines of evidence (Bellavite and Signorini, 1995). As suggested by Kroy (1989), in the living creatures there is an ancestral cybernetic order that is not based on the nervous system or on the humoral system (blood, hormones). This ancestral system is thought to be of an electromagnetic nature, because electromagnetic radiation is the most basic form of information carrier present in nature. Electromagnetic signals have constituted (and still constitute) both the language of communication between atoms and molecules and the means whereby primordial organisms received a series of items of information on the environment (sunlight, other cosmic waves). Living organisms have learnt to use electromagnetism as an information signalling system and even as a means of communication between cells and tissues. According to the studies by Popp and coworkers (Popp 1985; Popp et al. 1989; Ho and Popp 1994), many biological systems are capable of producing, receiving and even of “storing” electromagnetic waves such as light.

Detection and counting of specific cell populations by means of magnetic markers linked to monoclonal antibodies

We report on experiments aimed at the assessment of a new method for cell marking. This method combines superparamagnetic particles, commonly used for cell separation, linked to monoclonal antibodies, and biomagnetic instrumentation featuring an extremely high magnetic field sensitivity. The final goal of the method is to locate and estimate specific cell populations in the human body. In this experiment, quantitative features of the method are evaluated in vitro with lymphocytes and carcinoma cells. Comparison between estimation and direct counting of cells is quite satisfactory and motivates further development of the technique.

A SQUID based AC susceptometer for the investigation of large samples.

We developed a SQUID based susceptometer with a large available magnetized volume for the investigation of large objects. The magnetizing field is generated by a pair of Helmoltz coils. To achieve a high signal-to-noise ratio, the susceptometer is operated in a lock-in mode with an AC magnetizing field. A negative feedback control allows the rejection of the applied field with a relative residual of 1 x 10(-7). The apparatus was tested with substances of known magnetic susceptibility. The overall sensitivity, stated in terms of the magnetic moment, is better than 7 x 10(-11) A m2 for small samples.

Combined Effects of Electromagnetic Fields on Immune and Nervous Responses

In technologically developed countries, there is concern about hazards from electromagnetic fields (EMFs). Several studies have reported that immune and neuroendocrine systems exert an integrated response to EMF exposure. The aim of this review is to summarize the results of studies on the effect of low and high frequency EMF on immune and neuroendocrine systems on which our research group has been working for several years.

The use of an inhomogeneous applied field improves the spatial sensitivity profile of an in vivo SQUID susceptometer

We present a SQUID susceptometer with a non-homogeneous magnetizing field which is null at the sensing coil and increases towards the patient position with a constant gradient plus a cubic term at large distances. Compared with the magnetizing fields of similar instruments described in the literature, our gradient field enhances the signal due to internal organs with respect to the signal due to superficial tissue. Preliminary measurements have been performed on phantoms of known magnetic susceptibility. The advantage of using a non-homogeneous field compared with a uniform field has been investigated in the case of a double-layer phantom.