Theoretical analysis of the magnetocardiographic pattern for reentry wave propagation in a three-dimensional human heart model

We present a computational study of reentry wave propagation using electrophysiological models of human cardiac cells and the associated magnetic field map of a human heart. We examined the details of magnetic field variation and related physiological parameters for reentry waves in two-dimensional (2-D) human atrial tissue and a three-dimensional (3-D) human ventricle model. A 3-D mesh system representing the human ventricle was reconstructed from the surface geometry of a human heart. We used existing human cardiac cell models to simulate action potential (AP) propagation in atrial tissue and 3-D ventricular geometry, and a finite element method and the Galerkin approximation to discretize the 3-D domain spatially. The reentry wave was generated using an S1-S2 protocol. The calculations of the magnetic field pattern assumed a horizontally layered conductor for reentry wave propagation in the 3-D ventricle. We also compared the AP and magnetocardiograph (MCG) magnitudes during reentry wave propagation to those during normal wave propagation. The temporal changes in the reentry wave motion and magnetic field map patterns were also analyzed using two well-known MCG parameters: the current dipole direction and strength. The current vector in a reentry wave forms a rotating spiral. We delineated the magnetic field using the changes in the vector angle during a reentry wave, demonstrating that the MCG pattern can be helpful for theoretical analysis of reentry waves.     

ELF non ionizing radiation changes the distribution of the inner chemical functional groups in human epithelial cell (HaCaT) culture

Human skin cell culture (HaCaT) that has been exposed to an AC magnetic field undergoes detectable changes in its biochemical properties and shapes. Such changes were observed by infrared wavelength-selective scanning near-field optical microscopy with a resolution of 80-100 nm. We specifically investigated the changes in the distribution of the inner chemical functional groups and in the cell morphology induced by a 24 h exposure to a 1 mT (rms), 50 Hz sinusoidal magnetic field in a temperature regulated solenoid. These results further accentuate the crucial questions, raised by several recent studies, about the impact of low-frequency electromagnetic field on human cells.     

Archaeological records indicate a complex history of Pleistocene hunter-gatherer societies in Arabia

Paleolithic research on the Arabian Peninsula is still in its early stage. During the last decade, however, an increasing number of field projects were conducted and added significant data to the record. This development in addition to substantial paleoenvironmental research on Pleistocene climate and habitat changes creates a promising setting for research on human evolution in arid landscapes. Here I provide an overview of the main Paleolithic field projects conducted in Arabia and summarize their results.     

Vegetation Components of a Subtropical Rural Landscape in China

To assess the overall vegetation changes and their ecological significance, following landscape evolution, plant composition and physical structures of the homegardens (woodlots and vegetation patches with hedgerow fence) and field boundaries were examined in the rural landscape of subtropical China in order to determine their ecological significance. Field surveys on landscape changes and plant composition were carried out in two typical villages in the Yangtze river plain. Analysis of landscape changes and plant composition showed that the rural landscape is diverse both in terms of types of elements and plant species. The vegetation types in the area have undergone frequent alterations by human beings following major changes of landscape management due to economic and social reforms. The plant diversity of the various vegetation types in the area is related to the duration of colonization of the vegetation type, the extent of disturbance by human beings, and the physical structure diversity of the vegetation type. In the discussion, the plant diversity and heterogeneity of the physical environment in any vegetation type is of importance for the ecological sustainability of the landscape.     

Investigation of protein expression in magnetic field-treated human glioma cells

We previously reported phenotypic changes in human breast cancer cells following low-level magnetic field (MF) exposure. Here proteomic methods were used to investigate the biochemical effect of MF exposure in SF767 human glioma cells. Protein alterations were studied after exposure to 1.2 microTesla (microT) MF [12 milliGauss (mG), 60 Hertz (Hz)] +/- epidermal growth factor (EGF). SF767 cells were exposed for 3 h to sham conditions (<0.2 microT ambient field strength) or 1.2 microT MF (+/-EGF; 10 ng/ml). Solubilized protein fractions (sham; 1.2 microT; sham + EGF; 1.2 microT + EGF) were loaded for electrophoresis by 2D-PAGE and stained using a colloidal Coomassie blue technique to resolve and characterize the proteins. Protein patterns were compared across groups via Student's t-test using PDQUEST software. Cell profiles revealed significant alterations in the spot density of a subset of treated cells. Automated spot excision and processing was performed prior to peptide mass fingerprinting proteins of interest. Fifty-seven proteins from the detectable pool were identified and/or found to differ significantly across treatment groups. The mean abundance of 10 identified proteins was altered following 1.2 microT exposure. In the presence of EGF six proteins were altered after low magnetic field treatment by increasing (4) or decreasing (2) in abundance. The results suggest that the analysis of differentially expressed proteins in SF767 cells may be useful as biomarkers for biological changes caused by exposure to magnetic fields.     

Humoral (immunological) responses in female albino rats during rotating magnetic field exposures

Experiments were designed to evaluate the primary and secondary humoral responses to a rotating magnetic field configuration, which is known to evoke significant biobehavioral changes. Ten days after inoculation with human serum albumin and 10 days before a booster, female rats were exposed to eigher a 0.5 Hz rotating magnetic field (RMF) or to room conditions (control). The lighting schedule was either continuous or involved a light-dark cycle (LD) of 12:12h. A third group of rats served as colony room controls. Group differences of low statistical significance were found when females were exposed to continuous lighting rather than the LD 12:12 light-dark cycle. However, the effects were considered trivial and not sufficient to explain the previously reported biobehavioral changes evoked by this field configuration.     

Changes of blood volume distribution by postural changes in rats

During a space flight the human body responds to many different gravities. The launching of the rocket, the weightlessness, the re-entry of the spacecraft, and other factors influence the astronaut's body. The fluid shifts and the effect on the cardiovascular system arising from these gravitational changes have been frequently studied in space medicine by using body tilting, lower body negative pressure (LBNP) and centrifugal accelerators. There exist, however, few reports about the changes in whole body blood volume distribution caused by body tilting. These changes can be measured using radioisotopes: scintigraphy using 99mTechnetium-labeled human serum albumin (99mTc-HSA), etc. In humans, however, because the visual field of the scintillation camera is so small, the simultaneous measurement of whole body blood volume distribution cannot be done during body tilting. We therefore used rats, whose whole bodies can be encompassed within the visual field of the camera, and we discussed the changes in blood volume distribution induced by body tilting. We also measured the blood concentrations in each organ by using whole body autoradiography in mice, and discussed the effect of postural changes on some abdominal organs.     

Changes in the electrophoretic mobility of erythrocytes under the action of low-intensity pulsed magnetic field

Exposure of intact rats and human erythrocytes to low-intensity pulsed magnetic field leads to similar biphasic changes in the electrophoretic mobility of erythrocytes; this is accompanied by modification of their membrane and cytoskeletal protein spectrum.     

The effect of the extremely weak field on the cultures of bacteria Escherichia coli and Staphylococcus aureus

The effect of extremely weak human electromagnetic field on the suspensions of Escherichia coli and Staphylococcus aureus in a physiological solution at 25 degrees C was studied. The results obtained indicate that the human field induces changes in the physical properties of liquid water in physiological solution and the induced structural and dynamic rearrangements of extracellular water are tranferred to bacterial cells and change their functional activity.     

Change in the percent of lactate dehydrogenase isoenzyme level in testes of animals exposed to superhigh frequency radiation

The content of six lactate dehydrogenase isoenzymes in testes of rats exposed to electromagnetic field of 3-cm wavelength range was studied. The changes in their percent contents were found to be inhomogeneous compared with control. It is assumed that electromagnetic radiation affects the organs of the human urinogenital system. The results can be used for estimating the safety of persons professionally exposed to electromagnetic radiation of the industrial frequency range and in the therapy of diseases of the urinogenital system.     

Evolution of hominoids and the search for a genetic basis for creating humanness

The phylogenetic relationship of human and apes are reviewed. The history of molecular phylogenetic studies in this field is then discussed, as is the role of natural selection at the molecular level. It is argued that approximately 10,000 genetic changes are responsible for creating human specific phenotypes. A genome-wide comparison is necessary to decipher those changes.     

The influence of local tissue conductivity changes on the magnetoencephalogram and the electroencephalogram.

We examined the influence of local tissue conductivity changes in the vicinity of a dipolar source on the neuromagnetic field and the electric scalp potential using a high resolution finite element method model of the human head. We found that the topology of both the electric scalp potential and the neuromagnetic field (and consequently dipole localization) is influenced significantly by conductivity changes only in voxels adjacent to the source. Conductivity changes in these voxels yield a greater change in the amplitude of the magnetic field (and consequently in the dipole strength) than in the amplitude of the electric potential.     

The effect of a constant magnetic field on components of protein structures in human blood

A study on the effects of a constant magnetic field on the components of the protein structures in human blood was conducted by the methods of electron spectroscopy, optic aggregometry, and electrophoresis on an agarose gel. It was found that protein structures of different localizations experience the primary effect of a constant magnetic field. As a result, the total charge, form, and linear dimensions of the molecules change, as well as the rotation frequency of the components around valence bonds; this leads to changes in the spatial structures of the blood protein components. It was suggested as a working hypothesis that an increase in the intensity of oxidation processes under the effect of a magnetic field and, consequently, an increase in the negative activities of oxygen metabolites underlie these changes.     

Changes in the electrophoretic mobility of erythrocytes by the action of low-intensity pulse magnetic field

It has been shown that the exposure of "intact" rats and human blood to low-intensity pulse magnetic field leads to similar changes in the electrophoretic mobility of erythrocytes, which may be connected with the modification of the spectrum of their membrane proteins.     

Unicausal theories of human canine evolution: are they sufficient?

Most theories of human canine evolution are unicausal and only purport to explain size and related shape changes in human canines. The present work tests whether one of the morphological changes, dulling of the distal edge of the maxillary canine, can be entirely explained as a byproduct of changes in the overall shape of the canine. The data show that the distal edge of maxillary canines of A. afarensis became far duller than would be predicted from changes in crown shape. The greater than expected dullness of the distal edge can be explained by evolutionary changes in the genetic field for cheek tooth morphology. This suggests that human canine evolution is complex and cannot be accounted for by unicausal theories.     

A replication study of human exposure to 60-Hz fields: effects on neurobehavioral measures.

The purpose of this study was to reproduce and extend an earlier investigation of the effects of human exposure to combined, 60-Hz electric and magnetic fields. This paper presents the neurobehavioral results. Thirty men participated in one training session and four testing sessions. Subjects were randomly assigned to two groups. The 18 subjects in Group I were exposed (9 kV/m, 20 microT) and sham exposed in two counterbalanced orders. In Group II, half of 12 subjects were exposed (9 kV/m, 20 microT) every session, and the remaining half were sham exposed every session. The study was doubly blinded. Measures of cardiac interbeat interval, event-related brain potentials, and performance were obtained before, during, and after exposures. As in the earlier study, exposure to the combined field resulted in a statistically significant slowing of heart rate, in changes in late components of event-related brain potentials, and in decreased errors on a choice reaction-time task. In addition, field effects on several other measures approached statistical significance. The physiological measures obtained during exposure indicated that effects were greatest soon after the field was switched on, and again when it was switched off. The data indicate that changes in exposure level may be more important than duration of exposure for producing effects in human beings.     

Exposure and fetal growth-associated miRNA alterations in the human placenta

Researchers have begun to examine epigenetic alterations in the placenta, making key advances in understanding the epigenetic regulatory mechanisms of the placenta that define underlying processes of human development and disease. Examining changes in microRNA (miRNA) expression associated with environmental exposures and fetal growth is providing critical insights into the biology of development, response to in utero exposure, and future disease risk assessment. This review aims to highlight previous studies describing changes in miRNA expression in the human placenta associated with in utero exposure and fetal growth and seeks to assess the future directions in this exciting field of research.     

低频交变磁场对肿瘤细胞作用的理论分析和实验结果

本文研究了低频交变磁场对细胞作用的理论机理和实验结果。交变磁场和交变磁场感应的电场对运动离子产生电场力,加速离子的运行。基于该理论分析,设计了一系列的实验来验证假定的理论,实验采用两种肿瘤细胞系（HL-60 and SK-Hep-1）。将肿瘤细胞暴露于50Hz,20mT连续正弦磁场4天,每24小时检测上清液Na^＋和K^＋浓度。结果发现,照射组和对照组的Na^＋和K^＋浓度有显著变化,实验结果和理论分析相符。     

Effects of ultra-strong static magnetic field on the gut microbiota of humans and mice

To explore the effect of ultra-strong static magnetic field on gut microbiota, 16 T static magnetic field was used to study the changes in the structure and composition of human and mouse gut microbiota in this environment. In the mouse gut microbiota, at the genus level, the magnetic field significantly decreased the relative abundances of Escherichia-Shigella, Lactobacillus, Enterococcus, Burkholderia-Caballeronia-Paraburkholderia, Parasutterella, and Ralstonia and significantly increased those of Parabacteroides, Alloprevotella, Alistipes, Odoribacter, Bacteroides, Mucispirillum, Sutterella, and Prevotellaceae_UCG-001. Similarly, at the genus level, the relative abundances of Bacteroides, Parabacteroides, Romboutsia, and Streptococcus significantly decreased in the human gut microbiota. Contrary to the changing trend of the abundance in the mouse gut, the abundances of Bacteroides and Parabacteroides in the human gut were significantly reduced under magnetic field. The BugBase phenotypic prediction analysis showed that the relative abundances of five phenotypes, including anaerobism, mobile elements, potential pathogenicity, stress-tolerant, and biofilm formation, changed significantly in the mouse gut microbiota, while the relative abundances of two phenotypes, including Gram-positive and Gram-negative phenotypes, changed significantly in the human gut microbiota. The 16 T magnetic field could differently affect the composition, structure, and phenotypes of gut microbiota in human and mice, suggesting the importance of model selection in studying the biological effects of magnetic field.     

蛋白质组学技术在精子蛋白研究中的应用

从蛋白质组学研究的技术手段、蛋白质组学在人类不育及精卵相互识别并结合的机理研究、免疫法开展男性避孕方法的研究及蛋白质组学研究方法在家畜繁殖环节中的应用等几个方面阐述了蛋白质组学在人类生殖及动物繁殖环节相关研究中的重要作用。说明蛋白质组学已经成为生命科学未来发展的主要分支之一,为揭示生命个体的蛋白质动态变化提供了技术手段和理论基础,并将在药物开发,生命活动机理研究等方面发挥巨大作用,也必将会在家畜繁殖学领域发挥其应有的作用。