Biomedical subjects

P A Anninos

Publications and source records attributed to P A Anninos.

At least 19 recordsLinked to original sources

PubMed2001

Fetal magnetocardiogram recordings and power spectra analysis in biomagnetic arrhythmic signals.

In this study we investigated fetal arrhythmias using a Superconductive Quantum Interference Device (SQUID) in a shielded environment of low magnetic noise. The subjects involved were 84 pregnant women, 1941 years old (mean=30.55, SD=7.18) with single normal uncomplicated pregnancies and gestational ages 2532 weeks and 68 pregnant women 2342 years old (mean=32.89, SD=5.28), treated with ritodrine for the risk of preterm labour; with gestational ages 2635 weeks. Fourteen fetuses were found with cardiac arrhythmia six cases with tachycardia, one with bradycardia and seven with supraventricular/ ventricular (S/V) extrasystoles. Power spectra analysis of fetal magnetocardiographic arrhythmic signals assesses the functional state of their autonomic nervous system. Thus, magnetocardiography and power spectral analysis of the arrhythmic signals inform us that there is no deviation in the physiological process of the fetal heart in cases of fetal arrhythmia.

Journal Article↗

PubMed2001

SQUID biomagnetometry of the uterine arteries in normal and pre-eclamptic pregnancies.

AIM: This study was designed to investigate the hemodynamics of the uteroplacental circulation in normal and pre-eclamptic pregnancies using the biomagnetometer SQUID. METHOD: Twenty-two pregnancies complicated by pre-eclampsia and 49 normal pregnancies were included in this study. All were near term. Biomagnetic signals were recorded from the uterine arteries. After statistical Fourier analysis, the findings were designated in terms of spectral amplitudes as high (140-300 fT/square root of Hz), low (50-110 fT/square root of Hz) and borderline (111-139 fT/square root of Hz). RESULTS: The uterine artery waveforms and the corresponding spectral densities were of high amplitudes in most (89.7%) normal pregnancies and of low amplitudes in most (81.8%) pregnancies complicated by pre-eclampsia (p < 0.005). These findings were of statistical significance and were correlated with fetal heart rate (FHR) monitoring, pH, Apgar score at 1 and 5 minutes and birth weight percentiles: high amplitude cases were related with normal FHR patterns, pH > 7.25, Apgar score > 7 and birth weight > 75th percentile, while low amplitude recordings were connected with abnormal FHR patterns, pH < 7.25, Apgar score < 7, and birth weight < 10th percentile (8 cases) and < 50th percentile (10 cases). CONCLUSION: Biomagnetic measurement of the uterine artery flow, is a promising procedure in assessing fetal health, especially in high-risk pregnancies.

Adolescent↗

PubMed2000

Nonlinear analysis of brain activity in magnetic influenced Parkinson patients.

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 alpha-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.

Aged↗

PubMed2000

Differential diagnosis of breast lesions by use of biomagnetic activity and non-linear analysis.

PURPOSE: Breast cancer mortality rates have not changed during the past 60 years despite significant advances in screening methods. It is tempting therefore to use novel technology in order to better understand breast oncology. In this study we investigated the biomagnetic activity obtained in benign and malignant breast lesions using a single channel biomagnetometer SQUID (Superconducting Quantum Interference Device) in order to assess the method's efficacy in the differential diagnosis of these two types of lesions and its establishment as a screening technique. METHOD: Magnetic recordings were obtained from 21 patients with palpable breast lumps. Of these 11 were invasive carcinomas and 10 were benign breast lesions. We used non-linear analysis to investigate whether there is any biological differentiation in the dynamics in these two types of lesions. RESULTS: High amplitudes characterized the waveform of a malignant breast lesion whereas in benign breast lesions the corresponding amplitudes were low. Using the application of non-linear analysis we observed a clear saturation value for the dimension of malignant breast lesions and no saturation for benign ones. DISCUSSION: Biomagnetic measurements with the SQUID and the application of non-linear analysis are promising procedures in assessing and differentiating breast tumors.

Adult↗

PubMed1999

Differences in human visual evoked potentials during the perception of colour as revealed by a bootstrap method to compare cortical activity. A prospective study.

The aim of this prospective study was to investigate the colour related information in cortical activity as it is recorded from the scalp, by comparing the shape of the potential fields. Six healthy volunteers and two volunteers with known protanopsia were used to record multichannel visual evoked potentials after stimulation with chromatic stimuli of equally perceived brightness. The scalp fields resulting from each of the four chromatic stimuli were compared in pairs, in every possible combination and for each time point, using Efron's bootstrap method. It was found that, in comparison to other stimuli responses, the long dominant wavelength stimulus results in significant differences of cortical activity. These are mainly identified in two time periods: (a) at mid-latency responses, usually during the onset and development of P100 component, and (b) after the peak (on the decline) of P100 component. Similar but less evident behaviour was identified when the responses from the short dominant wavelength stimulus were compared with those from the other stimuli. Colour effects were not significant in protanops. The proposed method can be used to locate in time and quantify the differences in cortical activity during colour perception.

Adult↗

PubMed1999

Nonlinear analysis of biomagnetic signals recorded from the umbilical artery in normal and pre-eclamptic pregnancies.

OBJECTIVE: In this study we investigated the hemodynamics of the feto-placental circulation in normal and pre-eclamptic near term pregnancies using the biomagnetometer SQUID. Thirteen abnormal and 25 normal pregnancies were included in this study. STUDY DESIGN: The biomagnetic signals were analyzed using nonlinear analysis in order to differentiate these two types of pregnancies. RESULTS: The application of nonlinear analysis reveal a clear saturation dimension value for pre-eclamptic and non-saturation for normal pregnancies. These findings were statistically significant and were correlated with fetal heart rate monitoring, pH and Apgar score: high biomagnetic cases (140-300 fT/square root Hz) were related with normal patterns, pH>7.25 and Apgar >7, while low biomagnetic recordings (50-110 fT/square root Hz) were connected with abnormal patterns, pH<7.25 and Apgar <7. CONCLUSIONS: It is suggested that the biomagnetic measurements with SQUID and the application of nonlinear analysis, is a promising procedure in assessing fetal health, especially in high risk pregnancies.

Adolescent↗

PubMed1999

The chaos theory for differentiating fetal biomagnetic brain activity in normal and pre-eclamptic pregnancies.

In this study we investigated the fetal biomagnetic brain activity obtained in normal and pre-eclamptic pregnancies using a non-linear analysis. Measurements were performed using a single channel biomagnetometer superconducting quantum interference device (SQUID) in an electrically shielded room of low magnetic noise. Using the application of non-linear analysis and dimensionality calculations we have observed a clear saturation for the dimension of the fetal biomagnetic brain activity from pre-eclamptic pregnancies and no saturation for fetal brain activity in normal pregnancies. Thus, the biomagnetic measurements with the SQUID and the application of non-linear analysis, is a promising procedure in assessing and differentiating fetal biomagnetic brain activity in normal and pre-eclamptic pregnancies.

Journal Article↗

PubMed1999

Fetal magnetocardiogram recordings and Fourier spectral analysis.

Power spectral analysis of fetal magnetocardiogram (FMCG) data was evaluated in 64 pregnancies, using the non-invasive one channel superconducting quantum interference device (DC-SQUID), in order to investigate the power spectral amplitude distribution in the frequency range between 2 and 3 Hz. In all cases with normal and uncomplicated pregnancies, the data from the fetal heart and specifically the QRS complexes, were identifiable and unaffected by any maternal cardiac activity and furthermore the power spectral amplitudes, which varied between 120 and 350 fT/Hz, were directly related to gestational age.

Journal Article↗

PubMed1999

The use of non-linear analysis for differentiating the biomagnetic activity in ovarian lesions.

In this study we investigated the biomagnetic activity measured with the superconducting quantum interference device (SQUID) in benign and malignant ovarian lesions using non-linear analysis. We used a single channel biomagnetometer SQUID in order to measure the magnetic field emitted from benign and malignant ovarian lesions. We can differentiate such biomagnetic activities using non-linear analysis. Using the application of non-linear analysis in the ovarian lesions together with the use of dimensional calculations we have observed a clear saturation value for the dimension of malignant ovarian lesions and non-saturation for benign ovarian lesions. The biomagnetic measurements with the SQUID and the application of non-linear analysis in benign and malignant ovarian lesions, is a promising procedure in assessing and differentiating ovarian tumours.

Journal Article↗

PubMed1999

Fetal magnetoencephalogram recordings and Fourier spectral analysis.

This study investigates the fetal brain activity in normal and pre-eclamptic pregnancies. Measurements were performed by means of a Superconducting Quantum Interference Device (SQUID) in an electrically shielded room of low magnetic noise. The study was prospective. Eleven pregnant women with pre-eclampsia and 21 normal pregnancies were included. All were at 37-40 weeks of pregnancy. Biomagnetic signals (waveforms), recorded from the fetal brains in the frequency range of 2-7 Hz, were expressed in terms of magnetic power spectral amplitudes. These were low (mean, 376.67; SD, 28.66) in almost all normal pregnancies, and high (mean, 554.91; SD, 149.56) in most pregnancies complicated with preeclampsia. These findings were of statistical significance (Student's t -test, P < 0.005). Biomagnetic measurements of fetal brain activity is a promising screening procedure for assessing the cerebral function, especially in high risk pregnancies.

Journal Article↗

PubMed1999

The biological effects of magnetic stimulation in epileptic patients.

BACKGROUND: The magnetoencephalogram (MEG) is the magnetic activity emitted by the brain, which can be measured using a superconductive quantum interference device (SQUID). This is a totally non-invasive method for localizing functional healthy, epileptic and other CNS brain disorders. METHODS: Using the MEG brain activity recorded from epileptic patients we were able to obtain a mapping technique characterized by the ISO-spectral amplitude of scalp distribution of the MEG Fourier power spectrum. In addition, by utilizing the above recorded MEG activity we energize an electronic device, which emits back to the abnormal brain points of the epileptic patients magnetic fields with proper frequencies and intensities. RESULTS: Using this method we present here in more detail three randomly selected epileptic patients in which application of external magnetic fields of low intensities and frequencies produced a substantial attenuation of their abnormal brain activity. Furthermore, we present a statistical analysis of 50 randomly selected epileptic patients who underwent magnetic stimulation for the treatment of their seizures and we found that the anticonvulsant response to magnetic stimulation was statistically significant (chi 2 = 6.55, df = 1, p < 0.02). CONCLUSIONS: Our findings indicate that the use of low external magnetic fields produce substantial attenuation in seizure activity in epileptic patients and therefore it may open new ways in the future for management of epileptic activity.

Adult↗

PubMed1997

Spatiotemporal stationarity of epileptic focal activity evaluated by analyzing magnetoencephalographic (MEG) data and the theoretical implications.

BACKGROUND: The emitted brain neuromagnetic activity was recorded from patients suffering from idiopathic epilepsy, using a Superconductive Quantum Interference Device (SQUID). This activity will be referred as magnetoencephalogram (MEG). METHODS: The MEG recording which were obtained from 32 equal spaced points of a rectangular 4 x 8 matrix were analysed using Fourier statistical analysis. Then, a two dimensional brain mapping technique was utilized in order to detect the possible existence and the accurate localization of epileptic foci. The applied technique was based on the construction of ISO contour maps which are lines of equal power spectral amplitudes of the scalp spatial distribution of the recorded MEGs specific frequency bands. These maps will be referred as ISO-SA maps. A number of more than 200 epileptic patients were examined using this method. For each patient the magnetic brain activity was recorded for the temporal lobes, the frontal lobe and the occipital lobe. ISO-SA mappings were reconstructed for the frequency bands of the compound delta and theta rhythms (2-7 Hz), the alpha rhythm (8-13 Hz), and the beta rhythm (14-25 Hz). In these mappings epileptic (pathological) foci are represented as points emitting abnormal high magnetic power in the frequency band of 2-7 Hz. RESULTS: Systematic MEG measurements showed that the abnormal activity of a certain cortex region, when present, is stationary, i.e., time-invariant. CONCLUSIONS: Brain magnetic fields on the order of magnitude a picotesia are considered as to their possible physiologic nature, and a query is made as to what physical mechanisms might be involved in this propitiation.

Epilepsies, Partial↗

PubMed1992

Is the pineal gland involved in the pathogenesis of endometrial carcinoma.

The pathogenesis of endometrial carcinoma, which is the most common malignant neoplasm of the female genital tract, is unknown. It is believed that a prolonged period of increased estrogenic exposure unopposed by progesterone may underlie the malignant transformation of the endometrial cells. In the following communication, we propose that deficient melatonin functions may be an additional endocrine factor implicated in the pathogenesis of endometrial carcinoma. This hypothesis is based on the observations that: (a) melatonin has antiestrogenic properties; (b) melatonin stimulates progesterone production which opposes the action of estrogens; (c) an increased rate of endometrial hyperplasia, a premalignant condition, has been noted during the winter, a time of year associated with diminished melatonin secretion; (d) an increased incidence of anovulatory cycles, which is a risk factor for endometrial carcinoma, occurs in the winter; (e) melatonin secretion decreases sharply during the menopause, a period associated with an increased risk of endometrial carcinoma; (f) obesity, which is a major risk factor for endometrial carcinoma, is associated with impaired circadian melatonin secretion; (g) diabetes mellitus, which is an additional risk factor for endometrial carcinoma, is associated with decreased melatonin secretion and an increased rate of pineal calcification; and (h) the prevalence of endometrial carcinoma is lower in the black population compared to the white population. Similarly, the incidence of pineal calcification, which reflects the secretory activity of the gland, is significantly lower in the African and American black populations as compared to the white population.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

Is postmenopausal osteoporosis related to pineal gland functions?

There is currently considerable interest in the pathogenesis of postmenopausal osteoporosis, which is the most common metabolic bone disease. Osteoporosis affects approximately 20 million persons in the United States, 90% of whom are postmenopausal women. Although there is evidence that estrogen deficiency is an important contributory factor, the pathogenesis of osteoporosis is multifactorial and presently poorly understood. There is evidence that pineal melatonin is an anti-aging hormone and that the menopause is associated with a substantial decline in melatonin secretion and an increased rate of pineal calcification. Animal data indicate that pineal melatonin is involved in the regulation of calcium and phosphorus metabolism by stimulating the activity of the parathyroid glands and by inhibiting calcitonin release and inhibiting prostaglandin synthesis. Hence, the pineal gland may function as a "fine tuner" of calcium homeostasis. In the following communication, we propose that the fall of melatonin plasma levels during the early stage of menopause may be an important contributory factor in the development of postmenopausal osteoporosis. Consequently, plasma melatonin levels taken in the early menopause could be used as an indicator or perhaps as a marker for susceptibility to postmenopausal osteoporosis. Moreover, light therapy, administration of oral melatonin (2.5 mg at night) or agents which induce a sustained release of melatonin secretion such as 5-methoxypsoralen, could be useful agents in the prophylaxis and treatment of postmenopausal osteoporosis. Finally, since application of external artificial magnetic fields has been shown to synchronize melatonin secretion in experimental animals and humans, we propose that treatment with artificial magnetic fields may be beneficial for postmenopausal osteoporosis.

Aged↗

PubMed1992

The pineal gland and spontaneous abortions: implications for therapy with melatonin and magnetic field.

Spontaneous abortion, the termination of pregnancy prior to 20 weeks of gestation, is estimated to occur in 40%-50% of all pregnancies and in 12%-15% of identified pregnancies. The causes of spontaneous abortion can be divided into two main categories: those arising from chromosomal anomalies and those arising from abnormalities in the intrauterine environment. In the following communication, we propose that deficient pineal melatonin functions in early pregnancy may be causally related to the development of spontaneous abortions in cases where chromosomal anomalies or structural abnormalities of the uterus have been excluded. This hypothesis is based on the findings that: (a) melatonin plasma levels normally increase by 200%-300% in the first 20 weeks of pregnancy; (b) melatonin decreases uterine contractility in the rat; (c) melatonin stimulates the secretion of progesterone, which decreases uterine contractility and prevents immunological rejection of the trophoblast; (d) melatonin inhibits the synthesis of prostaglandins, which are potent inducers of uterine contractility and labor, and (e) pinealectomy increases the number of spontaneous abortions in pregnant rats. In addition, since melatonin is a hormone with immunosuppressant properties, we propose that the increased melatonin production in early pregnancy may contribute to a state of "transplantation immunity" to the paternal histocompatibility antigens preventing immunological rejection of the trophoblast. If this hypothesis is correct, then plasma melatonin, levels during early pregnancy could be used as an indicator for increased risk of spontaneous abortions.(ABSTRACT TRUNCATED AT 250 WORDS)

Abortion, Spontaneous↗

PubMed1992

Melatonin as a proconvulsive hormone in humans.

The pineal gland and melatonin exert a major influence in the control of brain electrical activity and have been shown to be involved in seizure and sleep mechanisms. Since pinealectomy has been reported to result in seizures in experimental animals, it is assumed that melatonin has anticonvulsant properties. Indeed, limited studies in humans with temporal lobe epilepsy indicate that melatonin attenuates seizure activity. In the present communication we present evidence, based on magnetoencephalographic (MEG) brain measurements, that melatonin may exert proconvulsive activity in humans as well. The proconvulsive properties of melatonin may explain several phenomena associated with epilepsy such as the increased occurrence of seizures at night when melatonin plasma levels are 5 to 8-fold higher than during the day and the observed exacerbation of seizures premenstrually and during pregnancy as well as the attenuation of seizures in the menopause. Furthermore, our findings suggest that anticonvulsants which decrease melatonin secretion, such as the benzodiazepines, may exert their antiepileptic activity by attenuating nocturnal melatonin secretion. Finally, we propose that patients with nocturnal epilepsy or those experiencing exacerbation of seizures premenstrually may benefit from the administration of agents which block the secretion or action of melatonin.

Adult↗

PubMed1992

Magnetic fields in the treatment of Parkinson's disease.

Levodopa-induced dyskinesias are a common complication of chronic dopaminergic therapy in patients with Parkinson's disease (PD). The overall prevalence of levodopa-induced dyskinesias ranges from 40%-90% and is related to the underlying disease process, pharmacologic factors, and to the duration of high dose levodopa therapy. The mechanisms underlying the emergence of levodopa-induced dyskinesias are unknown, although most investigators favor the theory that striatal dopamine receptor supersensitivity is directly responsible for the development of these abnormal movements. In laboratory animals, the pineal hormone melatonin has been shown to regulate striatal dopaminergic activity and block levodopa-induced dyskinesias (Cotzias et al., 1971). Since the pineal gland is known to be a magnetosensitive organ and as application of external magnetic fields has been shown to alter melatonin secretion, we studied the effects of application of external artificial weak magnetic fields in a Parkinsonian patient with severe levodopa-induced dyskinesias ("on-off"). Application of weak magnetic fields with a frequency of 2 Hz and intensity of 7.5 picotesla (pT) for a 6 minute period resulted in a rapid and dramatic attenuation of Parkinsonian disability and an almost complete resolution of the dyskinesias. This effect persisted for about 72 hours after which the patient regressed to his pretreatment state. To ascertain if the responses elicited in the laboratory were reproducible, the patient was instructed to apply magnetic fields of the same characteristics daily at home. These subsequent treatments paralleled the initial response with a sustained improvement being maintained during an observation period lasting at least one month. This case demonstrates the efficacy of weak magnetic fields in the treatment of Parkinsonism and motor complications of chronic levodopa therapy.

Combined Modality Therapy↗

PubMed1992

Magnetic fields alter the circadian periodicity of seizures.

We have recently reported that application of external, weak magnetic fields attenuated seizures in epileptic patients (Anninos et al., 1991). However, the mechanisms by which magnetic stimulation reduces seizure activity are unknown. We present four non-selected epileptic patients the first to be rated by the senior author, in whom treatment with magnetic fields attenuated the severity of seizures and also altered the circadian occurrence of seizures. The first patient, a 27-year old woman, had generalized tonic-clonic seizures which occurred almost exclusively at night. Following treatment with magnetic fields she experienced attenuation of seizures which then occurred only after waking up in the morning. The second patient, a 42-year old man, had generalized tonic-clonic seizures which occurred randomly during the day and night. Treatment with magnetic fields resulted in disappearance of nocturnal seizures with seizures now occurring exclusively during the day. The third patient, a 21-year old woman had generalized tonic-clonic seizures which occurred randomly during the day. After treatment with magnetic fields she was free of seizures for 7 months, but recently experienced one attack in the morning hours while sleeping. The fourth patient, a 39-year old woman had secondary generalized seizures since the age of 12. Prior to treatment with magnetic fields she had 8-10 seizures daily which occurred randomly during the day and night hours. Magnetic treatment resulted in attenuation in seizure frequency (1-2/day) with seizures now occurring only during the day. We propose, therefore, that since the pineal gland is a magnetosensitive organ which "transduces" environmental information of the light-dark cycle and of the earth's magnetic field into an endocrine message mediated via the circadian release of melatonin, and since it is recognized that melatonin attenuates seizure activity, artificial magnetic fields attenuate seizure activity by altering the functions of the pineal gland.

Adult↗