Search

Results of exhaustive application of neural network pattern recognition and classification of cases suffering from eyelid basal cell carcinoma are reported. Recognition and classification were based on shallow and deep learning methods; namely, multi-layer error backpropagation and convolution neural networks were utilized. The processed material consisted of full-face, or half-face photographs of healthy subjects and patients suffering from eyelid basal cell carcinoma. Various training and learning methods were used and the efficiency of the proposed algorithms was evaluated using as performance metrics the accuracy score, that is, the ratio of the number of the correctly classified cases over the total number of cases under examination. With respect to the accuracy, some of the proposed algorithms reached up to 100%.

Studies on a case of a woman that experienced many miscarriages without having any serious gynecological problems led us to search as an alternative to examine in a microbiological diagnostic laboratory her husband’s genital system. This test detected problems in man’s genital system. To overcome these problems, we thought of applying weak magnetic fields of the order of pT-TMS (pico-Tesla Transcranial Magnetic Stimulation) on man’s brain and genital system in order to influence his genital system for its proper function with respect to the movement, the density and the better penetration of the spermatozoa after ejaculation in his wife ovule.

Backround and Objectives: Alternative, non-invasive, and non-pharmaceutical options are gaining place in the battle of Alzheimer’s Disease treatment control. Lately, the magnetic stimulation of the brain is the most prevalent technique with encouraging results. The aim of this study is to establish any possible change on the Primary Dominant Frequencies (PDF) (range 2–7 Hz) of the affected brain regions in Alzheimer Disease (AD) patients after applying extremely weak Transcranial Magnetic Stimulation. Materials and Methods: For this purpose, all AD patients were scanned with the use of MagnetoEncephaloGraphy (MEG) recordings through a whole-head 122–channel MEG system. Results: Our results exerted statistically significant PDF changes due to weak TMS accompanied by rabid attenuation of clinical symptoms. Conclusion: Thus, this is the first time that a positive therapeutic effect is being demonstrated even at pico-Tesla range magnetic fields in a small clinical group of studies for AD.

The malignant tissues, by the virtue of their expansion increased ionic movements producing magnetic fields of higher intensity than the benign ones. In our studies the biomagnetic activity of prostatic carcinomas was found lower compared to breast carcinomas. These results could be explained by the lower angiogenic activity of prostate carcinomas, in comparison to other malignancies. In this chapter we describe the probable diagnostic value of biomagnetic activity measurements in evaluating prostate lesions.

Although rehabilitation practice for most patients consists of a combined use of thermotherapy that is produced from diathermy devices resulting faster and deeper heating to the patient, major concerns about occupational exposure to electromagnetic radiation for the operators must be considered. In most occasions, physiotherapists have involved multi-hour treatment sessions to different patients, resulting overuse of the diathermy device. Recently, our team along with other groups have raised serious concerns about the occupational safety aspects related to microwave diathermy (MWD) use. Driven by these recent reports, in this work, we tried to investigate the in vitro effects of a physiotherapist routine MWD device regarding its potential inflammatory biological effects that could be evoked in human cultured monocytes. Our results show that MWD does not alter the integrity of the cell membrane and, consequently, the viability of monocytes as assessed by Trypan blue and MTT measurements. Then again, members of the MAPK family (p38 and ERK1/2) were activated upon MWD exposure at 5-30 min, eventually leading to a time-dependent considerable increase in TNF-α production, a key pro-inflammatory mediator. Our results are indicative of a stress-activated phenomenon of monocytes upon MWD radiation, which could trigger potential hazardous cellular outcomes due to thermal and/or non-thermal bystander effects. Our results deserve further investigation, planned by our team in due course, to delineate the clinical correlations of these findings.

Magnetoencephalographic recordings, external picoTesla Transcranial Magnetic Stimulation (pT-TMS) and a double blind experimental design were used for the evaluation of 10 epilepsy patients (three males, seven females). Their ages ranged from 23 to 48 years. Our results showed an enhancement in the 2-7 Hz frequency range in five out of nine patients who had a statistically significant difference (55%). The pT-TMS could be a significant means for the treatment of epilepsy. Further research should be done prior to have final conclusions.

We investigated the beta rhythm in 10 children with autism disorders (six boys and four girls) aged 5-12 (mean± SD: 8.3± 2.1) before and after the application of pico Tesla transcranial magnetic stimulation (pT-TMS) using magnetoencephalography (MEG). The MEG was car-ried out in a magnetically shielded room with a whole-head 122-channel gradiometer. After applying pT-TMS, we observed a beta rhythm increase towards the frequency range of 18-26 Hz in seven out of 10 patients (70%). We created a score that rated the level of improvement for each patient: 1=some change; 2=minor change; and 3=major change. All patients had an improvement in their clinical symptoms after the application of pT-TMS. There was a correlation between the clinical score and the increase of channels in the frequency range 18-26 Hz after pT-TMS. We concluded that the application of pT-TMS affected the beta rhythm in children with autism disorder. Therefore, more studies need to be further conducted.

First results of the classification of the eyelid Basal Cell Carcinoma using Artificial Neural Networks are presented. Full, or half-face photographs of healthy subjects and patients suffering from eyelid Basal Cell Carcinoma were used to train and validate Artificial Neural Networks for the purpose of pattern recognition, identification and classification. The efficiency of the algorithm was tested using various training methods and it was evaluated using the accuracy score, that is, the ration of the number of the correctly classified cases over the total number of cases under examination. With respect to the accuracy, the proposed algorithm reached up to 100% performance. The algorithm is accompanied by a specifically designed and developed user friendly Graphical User Interface.

Aim: Rehabilitation practice for most patients consists of a combined use of thermotherapy that is produced from diathermy devices resulting faster and deeper heating to the patient, considerable concerns about occupational exposure to electromagnetic radiation for the operators has to be taken into account. In most occasions, physiotherapists have involved multi-hour treatment sessions to different patients, resulting overuse of the diathermy device. The time extended use of the device periodically leads to mechanical failures or troubleshooting of the machine which, in most cases, are not perceived by the operator of the device. All device's efficient functionality have a major impact on the completion of the treatment procedure in a large percentage of specific clinical conditions. If the device's operating condition is technically out of order or in a mode of over-activity, operators are mainly seeking solutions by reviewing the clinical case of the patient. This is eliminating their contribut...

Microwave diathermies (MWDs) are electromagnetic (EM) radiation emitting systems that are used by physiotherapists for thermotherapy treatment. Although this form of therapy is widely available in most physiotherapy units worldwide, management of the equipment is not obligatory addressed either by clinical engineers or medical physicists. A novel quality control (QC) protocol for MWD equipment, examining mechanical, electrical and electronic condition, the power output and EM radiation distribution in the electrotherapy room, was used during a national QC survey. The results of the survey revealed serious concerns about the safety of users and coexisting patients. The proposed approach could result in the introduction of EM-screened rooms, ensuring that MWD users and other persons in the vicinity will not be exposed to EM radiation over reference levels. International bodies could develop specific directives for EM radiation exposure in Physiotherapy Units, to conform to the proposed acceptance and functioning criteria for MDWs.

High-throughput technology like microarrays is widely used in the inference of gene regulatory networks (GRNs). We focused on time series data since we are interested in the dynamics of GRNs and the identification of dynamic networks. We evaluated the amount of information that exists in artificial time series microarray data and the ability of an inference process to produce accurate models based on them. We used dynamic artificial gene regulatory networks in order to create artificial microarray data. Key features that characterize microarray data such as the time separation of directly triggered genes, the percentage of directly triggered genes and the triggering function type were altered in order to reveal the limits that are imposed by the nature of microarray data on the inference process. We examined the effect of various factors on the inference performance such as the network size, the presence of noise in microarray data, and the network sparseness. We used a system theory approach and examined the relationship between the pole placement of the inferred system and the inference performance. We examined the relationship between the inference performance in the time domain and the true system parameter identification. Simulation results indicated that time separation and the percentage of directly triggered genes are crucial factors. Also, network sparseness, the triggering function type and noise in input data affect the inference performance. When two factors were simultaneously varied, it was found that variation of one parameter significantly affects the dynamic response of the other. Crucial factors were also examined using a real GRN and acquired results confirmed simulation findings with artificial data. Different initial conditions were also used as an alternative triggering approach. Relevant results confirmed that the number of datasets constitutes the most significant parameter with regard to the inference performance.

Rehabilitation practice for many patients consisting of a combined use of magneto therapy resulting emission of low frequency magnetic fields to the patient, elicit concerns about occupational exposure to electromagnetic radiation (EMR) for the operators. The time extended use of the device periodically leads to mechanical failures or troubleshooting of the machine which, in most cases, are not perceived by the operator of the device. All device’s efficient functionality have a major impact on the completion of the treatment procedure in a large percentage of specific clinical conditions. If the device’s operating condition is technically out of order or in a mode of over-activity, operators are mainly seeking solutions by reviewing the clinical case of the patient. This eliminates their contribution during the primary therapeutic plan or increases the treatment sessions. In this work, an extended survey is presented including 75 physiotherapy centres concerning usability and maintenance issues of magneto therapy devices throughout Greek territory combined with extended measurements of Electromagnetic Radiation in the unit room were performed. Physiotherapists’ perceptions revealed lack of technical support, maintenance and safe use of magneto therapy devices that extract auxiliary observations upon their clinical practice routines. Additionally safety measurements have not revealed field strengths over International Reference Levels which could result health risks for users and coexisting patients. The pilot survey that conducted in Attica and Western Greece confirms that magnetic fields strength that are measured are in accordance with the statutory legislation but will, at the same time, revealed lack of maintenance of the devices. Deficiency in topics such as proper equipment function will necessitate the creation of quality safety protocols, concerning the use of magneto-therapy, with the main aim the improvement of treatment procedures for the higher performance of therapeutic rehabilitation services to patients. Finally in this work, the proposal of a QC protocol for magnetotherapy devices is proposed for evaluation.

Magnetoencephalographic (MEG) recordings of the brain in Parkinson's disease were obtained in order to look for possible effect of pico-Tesla transcranial magnetic stimulation (pT-TMS). We found a significant effect of an increase of frequencies in the range of 2-7 Hz across subjects. In addition, we observed the mean peak frequency difference within the 2-7 Hz band towards frequencies of less or equal to those frequencies of the alpha frequency range (8-13 Hz).

Magnetoencephalography (MEG) is the recording of the magnetic field produced by the flowing of ions in the brain. This article reports our experience in the application of MEG in patients and healthy volunteers in the Greek population. We provide a brief description of our research work. The MEG data were recorded in a magnetically shielded room with a whole-head 122 channel or an one-channel biomagnetometer. Our results lead us to believe that the MEG is an important research field which is evolving quickly with a number of interesting findings with respect to normal and abnormal functions of the human brain. It could provide clinical practice with an easy to perform non invasive method, which could be adjunct to conventional methods for the evaluation of brain disorders.

Microwave diathermy (MWD) is a therapeutic system that has been in use for some decades now in all physiotherapy settings, following the regulations of national facility establishments. The validity of diathermy devices is probably reduced as their working time increases, introducing the need for the device to be controlled/reset by qualified personnel in order to maintain its effectiveness in sessions and to accurately deliver the energy output that the physiotherapist asks for. However, while MWD has been a vital tool for practising physiotherapists, there is no clear evidence of a health burden due to incorrect usability. Additionally, due to the fact that physiotherapy rooms contain physiotherapeutic equipment it is observed that during the use of the diathermy device there is spatial heterogeneity in the interior space. In this work, the results are presented of the first national survey for quality control of MWD systems installed in physiotherapy rooms existing in urban and rural areas in Greece. Serious concerns about the technical status of the equipment as well as staff and patient safety, regarding the levels of non-ionising radiation emitted from MWD devices, are discussed. Additional evaluation is included of measurements in empty physiotherapy rooms while the MWD unit is transmitting at three different input powers (50 W/100 W/150 W-these are the therapeutic protocols used most frequently by physiotherapists) and in fully equipped physiotherapy rooms. Field strengths measured around MWDs normally working at different angles, distances and times compared to international limits revealed great spatial and time heterogeneity, raising serious concerns about the safety of occupational workers or other patients.

The purpose of this study was to use magnetoencephalography (MEG) to identify epileptic zones in patients with brain tumors before undergoing tumor surgery. The MEG data were recorded with a 122-channel biomagnetometer. Equivalent current dipoles (ECD) were calculated for epileptic spikes on MEG recordings according to the single dipole model. Eight patients (five males and three females) within the age range (43-73 years; mean ± SD = 55.12 ± 9.77) were examined by MEG before neurosurgery operation. Four patients had meningioma grade I, three had glioblastoma grade IV and one had astrocytoma grade II. All the patients showed ECD at their MEG's before surgical operation except a female one with meningioma who showed no ECD. Tumors observed in the frontal areas show posteriorly located ECD. We conclude that the MEG is a valuable clinical tool for the localization of epileptic foci in patients with brain tumors before surgical tumor operation.

Magnetoencephalographic (MEG) recordings from the brain of 10 children with autism (6 boys and 4 girls, with ages range from 5-12 years, mean[Formula: see text][Formula: see text][Formula: see text]SD: 8.3[Formula: see text][Formula: see text][Formula: see text]2.1) were obtained using a whole-head 122-channel MEG system in a magnetically shielded room of low magnetic noise. A double-blind experimental design was used in order to look for possible effect of external pico-Tesla Transcranial Magnetic Stimulation (pT-TMS). The pT-TMS was applied on the brain of the autistic children with proper field characteristics (magnetic field amplitude: 1-7.5[Formula: see text]pT, frequency: the alpha - rhythm of the patient 8-13[Formula: see text]Hz). After unblinding it was found a significant effect of an increase of frequencies in the range of 2-7[Formula: see text]Hz across the subjects followed by an improvement and normalization of their MEG recordings. The statistical analysis of our results showed a statistical significance at 6 out of 10 patients (60%). It is also observed an increase of alpha activity in autistic children at the end of one month after pT-TMS treatment at home. In conclusion, the application of pT-TMS has the prospective to be a noninvasive, safe and important modality in the management of autism children.

Background Magnetoencephalography (MEG) is a well-established noninvasive method for investigating human brain activity. Objectives The present study aimed at identifying any change in the brain state after pico- Tesla Transcranial Magnetic Stimulation (pT-TMS) on patients with multiple sclerosis (MS). Methods A whole-head 122 - channel MEG system in a magnetically shielded room with low magnetic noise was used. The study population comprised of 2 male and 8 female volunteers with MS, with a mean age of 41.3 ± 9.5 years. External magnetic field of pT-TMS was applied on the above patients with proper field characteristics (magnetic field amplitude: 1 - 7.5 pT, frequency: the alpha rhythm of the patient 8 - 13 Hz), obtained prior to the application of pT-TMS. Results A significant effect was observed with an increase of frequencies in the range of 2 - 7 Hz among the participants. The results were statistically significant in 7 out of 10 patients (70%). Conclusions The pT-TMS has the prospective to be a significant noninvasive secure and effective means in managing MS symptoms.

Magnetoencephalographic (MEG) recordings of 10 multiple sclerosis (MS) patients (2 men, 8 women, mean 41.3±9.5 years, mean disease duration 12.7±7.2 years) were obtained using a whole-head 122 - channel MEG system in a magnetically shielded room of low magnetic noise. Our experimental design was double-blind in order to look for possible effect of external pico - Tesla Transcranial Magnetic Stimulation (pT-TMS). The external pT-TMS was applied on the MS patients with proper field characteristics (magnetic field amplitude: 1-7.5pT, frequency: the alpha-rhythm of the patient 8-13Hz) which were obtained prior to the application of pT-TMS. Each MS patient had two separate recording sessions consisting of 3 runs in between where were given real or sham pT-TMS. It was then tried to predict the real and sham stimulation sessions based on the changes in the mean peak frequency difference (MPFD) observed in the brain of the patients in the 2-7Hz frequency band. After unblinding it was found a significant effect of an increase of frequencies in the range of 2-7Hz across the subjects followed by an improvement and normalization of the MEG.

Microarray data are primarily used by gene regulatory network inference algorithms. We used dynamic artificial gene regulatory networks to evaluate the adequacy of time course microarray data to support the inference process. We evaluated the effect of different ways that genes can be triggered on the performance of an inference algorithm. We evaluated the effect of sparseness of a network on the inference performance. Finally we evaluated the effect of noise in microarray data on the inference process.

In this paper, the authors present mathematical models that describe individual neural networks of the Central Nervous System. Three cases are examined, varying in each case the values of the refractory period and the synaptic delay of a neuron. In the case where both the refractory period and the synaptic delay are bigger than one, the authors split the population of neurons into sub-groups with their own distinct synaptic delay. The proposed approach describes the neural regime of the network efficiently, especially in the case mentioned. Various examples with different network parameters are presented to investigate the network’s behavior.

Background: Non-linear signal analysis has proven to be a technique that is capable of revealing qualitative and quan- titative differentiations between different dynamical systems (biological or otherwise). In the present work it has been demonstrated that this capability reveals quantitative differences in the Magnetoencephalograms (MEG) received from patients with Idiopathic Generalized Epilepsy (IGE) and from healthy volunteers. Method: We present MEG record- ings of 10 epileptic patients with IGE and the corresponding ones from 10 healthy volunteers. A 122-channel SQUID biomagnetometer in an electromagnetically shielded room was used to record the MEG signals and the Grassber- ger-Procaccia method for the estimation of the correlation dimension was applied in the phase space reconstruction of the recorded signal from each patient. Results: The aforementioned analysis demonstrates the existence of spatially diffused low dimensionality in the MEG signals of patients with IGE. Conclusion: The obtained results provide support for the hypothesis that low dimensionality in MEG signals is linked to functional brain pathogeny.

Goals: Comparison of nitric oxide (NO) levels in cirrhotic patients with and without hepatic encephalopathy (HE), evaluation of possible correlation between HE and other clinical or laboratory characteristics, and estimation of utilization of NO levels in clinical practice. Background: HE is a neuropsychiatric complication of cirrhosis. The exact pathogenetic mechanisms underlying the presence of HE are not known. However, dysfunction of the NO pathway and ammonia detoxification are thought to play a major role. Study: Sixty-seven cirrhotic patients, 36 (53.7%) without HE, and 31 (46.3%) with HE were included in the study. Eighteen healthy individuals were used as control group. Clinical and laboratory data, including ammonia and stable end products of NO using Griess reaction, were collected. Results: NOx levels were statistically significantly higher in cirrhotic patients (225.5 μmol/L) than in control group [(67.94 μmol/L) (P = 0.000)]. NOx levels were, also, statistically significantly higher in patients with HE compared with patients without HE (324.67 μmol/L vs. 141.96 μmol/L, P = 0.000). Significant correlation between the presence of HE and NOx, ammonia, C-reactive protein, albumin, Model for End-Stage Liver Disease score, and Child-Pugh classification revealed. NOx levels also correlated with severity of HE. NOx and ammonia are independent factors predicting HE according to regression analysis. Diagnostic accuracy for the diagnosis of HE using a combination of NOx and ammonia was superior compared with standalone NOx or ammonia utilization. Conclusions: NOx levels are correlated with the presence and severity of HE. NOx levels determination, in addition to ammonia levels, could contribute in diagnosis of HE.

Complex binary sequences are generated through the application of simple threshold, linear transformations to the logistic iterative map. Depending primarily on the value of its non-linearity parameter, the logistic map exhibits a great variety of behavior, including stable states, cycling and periodical activity and the period doubling phenomenon that leads to high-order chaos. From the real data sequences, binary sequences are derived. Consecutive L bit sequences are given as input to a cellular automaton with the task to regenerate the subsequent L bits of the binary sequence in precisely L evolution steps. To perform this task a genetic algorithm is employed to evolve cellular automaton rules. Various complex binary sequences are examined, for a variety of initial values and a wide range of values of the non-linearity parameter. The proposed hybrid multiple-step-ahead prediction algorithm, based on a combination of genetic algorithms and cellular automata proved efficient and effective.

The abdominal pain is a very common disease in childhood, which lurks complications. Pediatric surgeons have to estimate at least 15 clinical and laboratory factors in order to make a diagnosis and decide about performing a surgical operation of the abdomen. Artificial Neural Networks (ANNs) are particular implementations of Artificial Intelligence (AI) systems and they are used in a wide area of application fields. This study examines the implementation of ANN architectures, using Multi-Layer Perceptron (MLP) neural networks and Probabilistic Neural Networks (PNN) architectures, in order to specify the appropriate ANN structure for abdominal pain estimation in childhood. The architecture with the best performance is a fully interconnected MLP neural network with an input layer of 15 nodes, one hidden layer of 5 neurons and an output layer, with error back-propagation algorithm being used as the learning scheme. In the output layer, the estimation of appendicitis' stage is reached automatically. The proposed ANN achieved a percentage of 88.5% of correct classification on testing set cases. Further analysis of obtained results, exhibited the ability of ANN for distinguishing the necessity of a case for operative treatment of abdominal pain based on diagnostic features, attaining a percentage of 100% of successful prognosis over the cases of testing set. The aim of proposed MLP neural network is to assist surgeons in appendicitis prediction, avoiding an unnecessary operative treatment.

Magnetoencephalographic (MEG) recordings of patients with CNS disorders were obtained using a whole-head 122-channel magnetometer SQUID and analyzed using Fourier statistical analysis. External transcranial magnetic stimulation in the order of pico Tesla (pTMS) was applied to the above patients with proper characteristics (magnetic intensity 1-7.5 pT; frequency: 8-13 Hz) which were obtained with MEG recordings prior to pTMS. The MEG recordings after the application of pTMS showed a rapid attenuation of the high abnormal activity followed by an increase in the number of the low frequency components toward the patients alpha-rhythm. The possible mechanisms of the effects of external magnetic stimulation on the pineal gland in the brain are presented.

Introduction: In the era of the new millennium, a lot of preclinical and clinical research is published. However, ethico-legal, cost-effectiveness and patient care issues are not addressed equally. Aim: To investigate whether abstracts presented at major international gastroenterology congresses refer to issues relevant to doctor-patient relationship, cost-effectiveness and care. Methods: We reviewed the abstracts on disk CD-ROMs of the United European Gastroenterology Week (UEGW) and the Digestive Disease Week (DDW), for the years 1998–2006. We used the following keywords: ethical/ethically, legal, consent, cost-effective/effectiveness, care, quality and tolerable/tolerability. Results: Over the study period, 1,612/20,018 (8.05%) and 764/45,628 (1.67%) abstracts including the above keywords were presented at UEGW and DDW congresses (p = 0.013), respectively. Statistically significant more abstracts containing separately any of the key words (apart from ‘legal’) were presented at the UEGW than at the DDW congress. There was a significant trend of increased referring to these key words over the study period for UEGW (p < 0.041) but not for DDW congresses (p = 0.70). Conclusion: The abstracts presented at the UEGW refer to ethico-legal, cost-effectiveness and patient care issues more frequently than those presented at the DDW. There is a trend of increased referring to these subjects at the UEGW but not at the DDW.

Background: In the last decade, the diagnostic approach of Gastrointestinal Stromal Tumors (GIST) has drastically changed with the utilization of tissue-specific biomarkers, such as c-Kit. However, a serum biomarker aiding in differential GIST diagnosis prior to surgery would provide added benefit in the daily clinical practice. Thus, the aim of the study was to investigate whether detection of c-Kit protein in the serum could be used as a reliable diagnostic biomarker. Methods: Twenty-seven patients with histologically confirmed GIST (16 men; age 41-80 years), 27 healthy controls (14 men; age 45-76 years) and 24 patients with submucosal tumors other than GIST (10 men; age 25-85 years) were enrolled in the study. Detection of serum c-Kit protein in blood samples of all patients prior to any treatment-related intervention and of healthy participants was accomplished using flow cytometry. The sensitivity and specificity of the assay were estimated. Results: Of the 27 patients with GIST, 25 were serum c-Kit positive. In the control group of 27 healthy participants, all except one were serum c-Kit negative, while among the 24 patients with tumors either than GIST, 22 were serum c-Kit negative and 2 were positive. Based on these results, the sensitivity of the assay was 92.6%, while the specificity was 96.3% when compared with the healthy volunteers and 91.7% in comparison with the non-GIST group. Conclusion: c-Kit protein detection with flow cytometry could represent a reliable sensitive and specific serum bioassay for differential GIST diagnosis.

Background: Low - frequency activity has been reported in Parkinson disease (PD). We investigated the magnetoencephalographic (MEG) recordings from PD patients and healthy volunteers in the frequency domain. Methods: The MEG recordings were carried out in a magnetically shielded room with a whole-head 122-channel gradiometer. Nine patients suffering from PD and 9 age and gender matched healthy subjects were included in the study. MRI with T1-w and T2-w images, was available in patients' records. Results: Frequency analysis may be usefully combined in the analysis of data sets, which contain oscillatory components. Prominent low frequencies can be seen in the spectrum obtained from the PD patients whereas in the control group the frequency range was 6Hz in the majority of channels. MRI did not disclose specific findings in any case. Conclusions: It is suggested that the MEG could be a complementary method in the diagnostic evaluation of PD using spatial distribution of the raw data in the frequency domain.

To evaluate the biomagnetic activity of a low-grade mucosa-associated lymphoid tissue (MALT-) type gastric lymphoma, and to determine if this procedure could be an adjunct to endoscopic ultrasonography (EUS) in the assessment of the disease pre- and postsurgically.A 47-year-old female with a 2-year clinical history of a low-grade MALT-type gastric lymphoma associated with Helicobacter pylori was examined. The disease showed no histologic remission after eradication of the H. pylori infection and subsequent treatment with chemotherapy and the patient was classified as stage II EA. A decision for surgical resection was made. Biomagnetic waveform recordings were made in the target area before and after surgery and the Fourier analysis of these recordings was performed.The gastric lymphoma biomagnetic waveforms showed high amplitudes (1.8 pT) before and low amplitudes (0.6 pT) after resection. The corresponding Fourier analysis demonstrated that the maximum spectral power of the presurgical measurement was elevated (mean 235 +/- 847 pT2/Hz) compared with that obtained postsurgically (mean 725 +/- 89 pT2/Hz). The difference was of statistical significance ( p0.0001, t-test).Biomagnetic monitoring of gastric lymphoma, which is an entirely new diagnostic modality, could be a supplement to EUS for assessing remission or persistence of disease with medical treatment during follow up.

Objective: The aim of this study is to investigate the influence of external magnetic stimulation (EMS) in epileptic patients using magnetoencephalographic (MEG) measurements and non-linear analytic techniques. Methods: The examined group consisted of 15 men aged 19-56 years (mean: 39.5±11.3) and 15 women aged 15-53 years (mean: 36.7±11.4 ). For each one the magnetic activity was recorded from 32 points for each temporal lobe. External magnetic stimulation (EMS) with proper field characteristics (intensity: 1-7.5 pT, frequency: the α-rhythm of the patient (8-13 Hz)) was applied in the frontal, occipital and temporal lobes for 2 to 6 minutes and the emitted brain magnetic activity was recorded again. In order to investigate if there is any alteration in the MEG complexity underlying the neural dynamics characterizing the pathologic brain before and after the EMS, chaotic analysis approach was applied for the estimation of the dimensional analysis of the existing strange attractors. Results: The application of EMS resulted in rapid attenuation of the MEG activity of epileptic patients. The obtained results of the dimensionality calculation provide a shift from lower to higher dimensional values. Such a shift is an indication that we are dealing with a chaotic system similar with the one characterizing normal subjects. Conclusions: The increased values of the dimensional complexity and the lower activity of the MEG after the application of EMS strongly supports the beneficial effects of EMS in epileptic patients.

In this study we investigated the fetal magnetocardiogram recordings (FMCG) in 64 women, 21-30 years old, with single normal pregnancies and gestational ages 28-40 weeks. Spectral analysis was used to quantify heart rate variability and to identify the maturation of the autonomic nervous system. According to our results, there was an increase of the ratio LF/HF of the power spectrum, which reflects the maturation of the autonomous nervous system and also an increase in heart rate variability in the course of pregnancies, which was statistically significant (ANOVA test, P < 0·0005) comparing the R-R intervals of the number of cases in the four groups of 28-30, 37-40, 31-33 and 37-40 weeks of gestation. This study highlights some of the advantages of FMCG as a novel, non-invasive technique for obtaining useful clinical information.

Magnetoencephalography (MEG) recordings were evaluated for 25 healthy female volunteers, in five different gustatory states: normal, sweet, bitter, sour and salty. The study population was divided in two groups according to age: group A (10-19 years old) and group B (20-30 years old). There was a higher count of low frequencies (2 Hz) and a lower count of high frequencies (7 Hz) with increasing age, in all studied states. We compared each state for the frequencies of 2 Hz and 7 Hz between the two groups. Statistically significant differences were found in the normal and sweet states for the frequencies of 2 Hz and 7 Hz and in the salty taste in the frequency of 7 Hz. We also intra-compared the five states in group A and the five states in group B for the 2 Hz and 7 Hz frequencies. The results were not statistically significant. A differentiation in the distribution of the frequencies with increasing age may provide new insights into the age-dependence of taste quality brain centers.

Background: Analysis of primary prevention studies of the use of β-blockers has shown clear reductions in variceal bleeding in cirrhotic patients with varices. In contrast, the usefulness of prophylactic endoscopic sclerotherapy, alone or in combination with propranolol, in the management of these patients is still under investigation. The present study compared the efficacy of combined sclerotherapy and propranolol versus propranolol alone in the primary prevention of hemorrhage in cirrhotic patients with varices and high (greater than 18 mm Hg) intraesophageal variceal pressure. Methods: Patients were randomly assigned to propranolol (42 patients) or to propranolol plus sclerotherapy (44 patients). The mean duration of follow-up was 26.8 ± 7.7 and 24.6 ± 9.8 months, respectively. Results: During this period 23% of the patients in the combination group experienced at least 1 episode of bleeding due to varices or congestive gastropathy as compared with 14% in the propranolol group (not significant). Twenty-three patients (52%) in the combination group developed complications as compared with 8 (19%) in the propranolol group (p = 0.002). The mortality rate was similar in both groups (14% and 18%, respectively). The only independent factor predictive of survival was the level of serum albumin. Conclusions: Endoscopic sclerotherapy should not be used for the primary prevention of hemorrhage in cirrhotic patients at high risk of variceal bleeding who are undergoing treatment with propranolol. (Gastrointest Endosc 2000;51:652-8.)

Magnetoencephalogram (MEG) recordings were obtained from the brain of patients suffering from Parkinson's disease (PD) using the Superconductive Quantum Interference Device (SQUID). For each patient the magnetic activity was recorded from a total of 64 points of the skull (32 points from each temporal lobe) as defined by a recording reference system, which is based on the 10-20 Electrode Placement System. Some of the recorded points were observed to exhibit abnormal rhythmic activity, characterized by high amplitudes and low frequencies. External magnetic stimulation (EMS) with intensity 1-7.5pT, and frequency the a-rhythm of the patient (8-13 Hz) was applied in the left-right temporal, frontal-occipital and vertex (2 minutes over each of the above regions) and the brain magnetic activity was recorded again. The application of the EMS resulted in rapid attenuation of the MEG activity of PD patients. Furthermore, chaotic dynamic methods were used, in order to estimate the correlation dimension D of the reconstructed phase spaces. The estimated values of D, in conjunction with the results derived from the other data analysis methods, strongly support the existence of low dimension chaotic structures in the dynamics of cortical activity of PD patients. In addition, the increased values of D of the MEG after the application of EMS when compared with the corresponding ones obtained from the MEGs prior to the EMS, suggest that the neural dynamics are strongly influenced by the application of EMS.

A hybrid model that consists of an Artificial Neural Network and Genetic Algorithm is used in order to select the most significant osteoporosis risk factors. The results indicated that just 8 to 10 parameters, out of a total 34, are essential in order of high performance to be achieved.

Nocturnal reflux has been associated with severe complications of gastro-oesophageal reflux disease and a poorer quality of life. Hiatal hernia predisposes to increased oesophageal acid exposure, but the effect on night reflux symptoms has never been investigated. The aim of the study was to investigate if hiatal hernia is associated with more frequent and severe night reflux symptoms.A total of 215 consecutive patients (110 male, mean age 52.6 ± 14.7 years) answered a detailed questionnaire on frequency and severity of specific day and night reflux symptoms. Subsequently, all patients underwent upper endoscopy and were categorized in two groups based on the endoscopic presence of hiatal hernia.Patients with hiatal hernia were more likely to have nocturnal symptoms compared to those without hiatal hernia (78.6 vs. 51.8%, p = 0.0001); 59.2% of patients with hiatal hernia reported heartburn and 60.2% regurgitation compared to 43.8 and 39.3% of those without hiatal hernia, respectively (p = 0.033 and p = 0.003). The proportions of patients with day heartburn or regurgitation were not significantly different between the two groups. Night heartburn and regurgitation were graded as significantly more severe by patients with hiatal hernia (4.9 ± 4.2 vs. 3.2 ± 3.7, p = 0.002, and 3.8 ± 4.2 vs. 2.2 ± 3.5, p = 0.001, respectively). Patients with hiatal hernia had more frequent weekly night heartburn and regurgitation compared to those without hiatal hernia (p = 0.004 and p = 0.008, respectively).More patients with hiatal hernia reported nocturnal reflux symptoms compared to those without hiatal hernia. Furthermore, nocturnal reflux symptoms were significantly more frequent and graded as significantly more severe in patients with presence of hiatal hernia rather than in those without hiatal hernia.

A medical database of 589 women thought to have osteoporosis has been analyzed. A hybrid algorithm consisting of Artificial Neural Networks and Genetic Algorithms was used for the assessment of osteoporosis. Osteoporosis is a common disease, especially in women, and a timely and accurate diagnosis is important for avoiding fractures. In this paper, the 33 initial osteoporosis risk factors are reduced to only 2 risk factors by the proposed hybrid algorithm. That leads to faster data analysis procedures and more accurate diagnostic results. The proposed method may be used as a screening tool that assists surgeons in making an osteoporosis diagnosis.

We generalize the clustering theorem by Lanchier (2012) on the infinite one-dimensional integer lattice ℤ for the constrained voter model and the two-feature two-trait Axelrod model to multitype biased models with confidence threshold. Types are represented by a connected graph Γ, and dynamics is described as follows. At independent exponential times for each site of type i, one of the neighboring sites is chosen randomly, and its type j is adopted if i, j are adjacent on Γ. Starting from a product measure with positive type densities, the clustering theorem dictates that fluctuation and clustering occurs, i.e., each site changes type at arbitrary large times and looking at a finite interval consensus is reached asymptotically with probability 1, if there is one or two vertices of Γ adjacent to all other vertices but each other. Additionally, we propose a simple definition of clustering on a finite set, in which case one can apply the clustering theorem that justifies known previous claims.

Our intention in this work is to show, by using two different methods, that magnetospheric dynamics reveal low dimensional chaos. In the first method we extend the chaotic analysis for the AE index time series by including singular value decomposition (SVD) analysis in combination with Theiler's test in order to discriminate dynamical chaos from self-affinity or "crinkliness". The estimated fractality of the AE index time series which is obtained belongs to a strange attractor structure with close returns in the reconstructed phase space. In the second method we extend the linear equivalent magnetospheric electric circuit to a nonlinear one, the arithmetic solution of which reveals low dimensional chaotic dynamics. Both methods strongly support the existence of low dimensional magnetospheric chaos.