Development and evaluation of intermediate frequency magnetic field exposure system for studies of in vitro biological effects

We have developed an intermediate frequency (IF) magnetic field exposure system for in vitro studies. Since there are no previous studies on exposure to heating-frequency magnetic fields generated from an induction heating (IH) cook top, there is a strong need for such an exposure system and for biological studies of IF magnetic fields. This system mainly consists of a magnetic-field-generating coil housed inside an incubator, inside which cultured cells can be exposed to magnetic field. Two systems were prepared to allow the experiment to be conducted in a double-blind manner. The level of the generated magnetic field was set to 532 microT rms in the exposure space, 23 kHz, 80 times the value in the International Commission on Non-ionizing Radiation Protection (ICNIRP) guidelines, with a spatial field uniformity better than 3.8%. The waveforms were nearly sinusoidal. It was also confirmed that the parasitic electric field was 157 V/m rms and the induced electric field was 1.9 V/m rms. The temperature was maintained at 36.5 +/- 0.5 degrees C for 2 h. Furthermore, leaked magnetic flux density was 0.7 microT rms or lower at extremely low frequency (ELF) and IF in the stopped system when the other system was being operated, and the environmental magnetic flux density was 0.1 microT rms or lower at the center of the coils. As a result, it was confirmed that this system could be successfully used to evaluate the biological effects of exposure to IF magnetic fields.     

Action of neltenexine on anion secretion in human airway epithelia

Neltenexine has been applied to human lung diseases such as chronic obstructive pulmonary disease (COPD) as a mucolytic agent. However, we have no information on the neltenexine action in bronchial epithelial cells. We studied the neltenexine action on the ion transport in human submucosal serous Calu-3 cells. Under a hyper-secreting condition caused by terbutaline (a beta2-adrenergic agonist), neltenexine diminished anion secretion by inhibiting the Cl- and HCO3- uptake via Na+/K+/2Cl- cotransporter and Na+/HCO3- cotransporter without blockade of the cystic fibrosis transmembrane conductance regulator (CFTR) channel, and also diminished anion secretion via stimulation of Cl-/HCO3- exchanger, which facilitates the extrusion of more CFTR-permeant anion, Cl-, with the uptake of less CFTR-permeant anion, HCO3-. Thus, neltenexine reduced the hyper-secretion to keep an appropriate fluid level in the airway, providing a possibility that neltenexine can be an effective drug in airway obstructive diseases by decreasing the airway resistance under a hyper-secreting condition.     

Cyclodextrin-linked alginate beads as supporting materials for Sphingomonas cloacae, a nonylphenol degrading bacteria

Calcium alginate beads covalently linked with alpha-cyclodextrin (alpha-CD-alginate beads) were prepared and examined for their ability to serve as a supporting matrix for bacterial degradation of nonylphenol, an endocrine disruptor. Column chromatographic experiment using alpha-CD-alginate beads with diameter of 657+/-82 microm and with degree of CD substitution of 0.16 showed a strong affinity for nonylphenol adsorption. Although addition of alpha-CD (2.7-27 mM) to the culture broth of Sphingomonas cloacae retarded nonylphenol degradation, the immobilized bacteria on the CD-alginate beads were effective for the degradation. Batch degradation tests using the immobilized bacteria on alpha-CD-alginate-beads showed 46% nonylphenol recovery after 10-day incubation at 25+/-2 degrees C, and the recovery reached to about 17% when wide and shallow incubation tubes were used to facilitate uptake of the viscous liquid of nonylphenol on the surface of the medium. Scanning electron microscopic photographs revealed that multiplicated bacteria was present both on the surface and inside the beads and the matrix of CD-alginate was stable and suitable during 10-day incubation.     

Effects of functional overloading on the regenerative potential of injured skeletal muscles in mice

The purpose of this study was to investigate the effects of functional overload on the regeneration of injured skeletal muscles of male C57BL/6J mice. To activate a necrosis-regeneration cycle, cardiotoxin (CTX) was injected into soleus muscles both control and functionally overloaded groups. The recovery of muscle protein content, which was decreased by CTX injection, was significantly stimulated by application of functional overloading. The CTX-injection-related increment of satellite cell number in the overloaded groups was also greater than that in the group without overloading. Evidences suggest that the application of a mechanical stress on the injured skeletal muscles could activate satellite cells and facilitate the regeneration of the muscle.     

Nanobiotechnology: quantum dots in bioimaging

Many biological systems, including protein complexes, are natural nanostructures. To better understand these structures and to monitor them in real time, it is becoming increasingly important to develop nanometer-scale signaling markers. Single-molecule methods will play a major role in elucidating the role of all proteins and their mutual interactions in a given organism. Fluorescent semiconductor nanocrystals, known as quantum dots, have several advantages of optical and chemical features over the traditional fluorescent labels. These features make them desirable for long-term stability and simultaneous detection of multiple signals. Here, we review current approaches to developing a biological application for quantum dots.     

Age-related changes of dietary intake and blood eicosapentaenoic acid, docosahexaenoic acid, and arachidonic acid levels in Japanese men and women

We studied the relationship between dietary intake and the blood compositions of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid (ARA) in four study groups with different ages and sexes. One hundred and four subjects were recruited. Dietary records together with photographic records from 28 consecutive days were amassed and the fatty acid composition in erythrocyte membranes and plasma lipid fractions was analyzed. Fish intake in the elderly group was significantly higher than that in the young group in both men and women. The compositions of ARA in erythrocytes and plasma phospholipids in the elderly were lower than those in the young, but the ARA intake was nearly identical. In the elderly group, the percentage of dietary ARA consumed at the same time as EPA and DHA derived from fish was high. We considered that these fatty acids markedly inhibited the incorporation of dietary ARA into blood phospholipids.     

N-glycans linked to glycoproteins in edible beans (zatsu-mame): natural resources for bioactive oligosaccharides

In this study, we analyzed structural features of the N-glycans linked to glycoproteins expressed in various edible beans to identify excellent sources of useful N-glycans and N-glycopeptides. Structural analysis of N-glycans of the glycopeptides prepared from the pepsin digests of bean powder that the useful high-mannose type N-glycans occur predominantly in Phaseolus and Vigna beans; tora bean for Man?GlcNAc?-Asn, dainagon bean for Man?GlcNAc?-Asn, and azuki bean for Man?GlcNAc?-Asn.