Shinji Harakawa

Immunization with Recombinant Surface Antigen P50 of Babesia gibsoni Expressed in Insect Cells Induced Parasite Growth Inhibition in Dogs

ABSTRACT This is a report of a vaccine trial directed against Babesia gibsoni infection in dogs with the use of the recombinant antigen P50. Dogs immunized with P50 showed partial protection manifested as a significantly low level of parasitemia. The results indicated that P50 is a primary vaccine candidate molecule against canine B. gibsoni infection.

Effect of 50 Hz electric field in diacylglycerol acyltransferase mRNA expression level and plasma concentration of triacylglycerol, free fatty acid, phospholipid and total cholesterol

BackgroundThe effects of exposure to a 50 Hz electric field (EF) on plasma level of triacylglycerol, free fatty acids, total cholesterol and phospholipid and mRNA expression level of diacylglycerol acyltransferase (DGAT) 1 and 2 in liver and intestines from C57BL/6 J mice were studied.MethodsThe test was based on comparison between mice post treated with 50 Hz EF of 45 kV/m intensity for 30 min per day for 11 days or without EF. DGATs mRNA expression was analyzed by real-time quantitative polymerase chain reaction.ResultsThere was no difference in the gene expression level of DGAT1 in liver and intestines. The DGAT2 gene expression level in liver derived from mice treated with EF was significantly lower than those in the control (P < 0.001). Both plasma total cholesterol (P < 0.01) and phospholipid (P < 0.05) in the group exposed to EF were lower than those in the control, but there was no difference in triacylglycerol or free fatty acid levels.ConclusionExposure to 50 Hz EF decrease the plasma levels of total cholesterol and phospholipids, and downregulated DGAT2 mRNA expression in liver. The mechanisms for the effects of EF on lipid metabolism are not well understand yet, but altered DGAT2 activity may be involved.

Exposure to 50 Hz electric fields reduces stress-induced glucocorticoid levels in BALB/c mice in a kV/m- and duration-dependent manner

Electric fields (EFs) can reduce elevated levels of stress-related hormones in some organisms. In this study, endocrine effects of exposure to a 50 Hz EF were investigated in male BALB/c mice. Specifically, plasma glucocorticoid (GC) levels were examined because GC is known to mediate the stress response in mice, including changes induced by immobilization. Mice were exposed to 50 Hz EFs (at 2.5-200 kV/m) for 60 min. They were immobilized for the latter half (30 min). At the end of exposure period, blood samples were collected and GC levels estimated by spectrofluorometry. GC levels were not influenced by EFs in absence of immobilization, but they were significantly higher in immobilized mice than in non-immobilized mice (P < 0.01). Elevated GC levels induced by immobilization were significantly reduced by exposure to an EF at 10 kV/m (P < 0.05), and the effect of EFs at 0-10 kV/m on GC levels increased in a kV/m-dependent manner (P < 0.05). In contrast, following treatment with EFs at 50 and 200 kV/m, GC levels were higher than those observed at 10 kV/m. To assess the effect of EF treatment duration, mice were also exposed to 50 Hz EFs (10 kV/m) for 6, 20, or 60 min. Immobilization-induced increase in GC levels was significantly suppressed by EF exposure for 20 and 60 min. Therefore, our results demonstrate that extremely low-frequency EFs alter stress response of mice in a kV/m- and duration-dependent manner.

Structural and Immunochemical Studies on Bovine Lactoferrin Fragments

Lactoferrin (Lt) is a metal-binding protein found in milk and other secretory fluids and also in blood. It shows multifunctional properties but the mechanism of developing its function in living systems has not been resolved yet. It is known to exert bacteriostatic effects due to its ability to bind environmental iron. Moreover, apo-lactoferrin has been shown to bind to microbial membranes and causes the direct destruction of microorganisms. Other biological functions attributed to lactoferrin include roles in modulation of the inflammatory response, activation of the immune system, and control of myelopoiesis or cell growth. This molecule is constructed with N- and C-lobes, each of which is composed of 3 domains1. The function of each lobe has been studying and there are certain differences. The biologically significant function has been found mainly in N-lobe. For the aids of resolving their functional analysis, the authors prepared the monoclonal antibodies (mAb) against N-lobe and C-lobe of bovine lactoferrin. To prepare the mAb specific to N-lobe, we used lactoferricin® B (bLfcin, an anti-microbial peptide isolated from N-lobe2) as an antigen3. In this paper, the characterization of the mAb against lactoferrin fragments has been examined and the structure of the mAb-recognition site on lactoferrin molecule was identified.

Time-dependent changes in the suppressive effect of electric field exposure on immobilization-induced plasma glucocorticoid increase in mice

We recently reported that increased glucocorticoid (GC) levels in immobilized mice were suppressed by exposure to a 50-Hz electric field (EF) in kV/m-dependent and exposure duration-dependent manners. Here, we characterized time-dependent changes in the effect of EF exposure in immobilized mice. Using control, EF-alone, immobilization-alone, and co-treated groups, plasma GC levels, and blood properties were first measured (0-60 min) to observe changes induced by each treatment and measured again (60-120 min) to assess recovery from each treatment. The 50-Hz, 10-kV/m EF was formed in a parallel plate electrode. Co-treated mice were exposed to the EF for 60 min for the first measurement and were immobilized for the second half (30-60 min) of the EF exposure period. Plasma GC levels did not change significantly over time in the control and EF-alone groups. GC levels in the immobilization-alone and co-treated groups increased after immobilization, peaking 30 min after the start of immobilization and then decreasing gradually; however, the GC peak was lower in the co-treated group than in the immobilization-alone group (P < 0.05 at 50 and P < 0.001 at 60 min). Red blood cell counts, hemoglobin levels, and hematocrit values increased after immobilization but were not affected by the EF. Our findings indicate that the EF did not shift the peak of the time-dependent increase in plasma GC levels in immobilized mice but simply reduced it. Bioelectromagnetics. 38:272-279, 2017.

Configuration‐dependent variability of the effect of an electric field on the plasma glucocorticoid level in immobilized mice

We recently reported that an immobilization stress-induced increase in glucocorticoid (GC) level was suppressed in mice exposed to an electric field (EF) of 50 Hz in a kV/m-dependent manner. In this study, we investigated the reproducibility of the suppressive effect induced by EF exposure by varying the voltage and distance between the electrodes (0.5 kV/50 mm, 1 kV/100 mm, 2 kV/200 mm) and comparing the effects on the plasma GC level. In addition, the effect of mice being in contact with the lower electrode or not was compared at 1 kV/100 mm. Immobilization-induced GC levels were significantly decreased in mice exposed to an EF at 1 kV/100 mm for 60 min (P < 0.01), but not in mice exposed to 0.5 kV/50 mm or 2 kV/200 mm. Furthermore, the suppressive effect of the 1 kV/100 mm EF was canceled when a polypropylene sheet (0.1 mm thick) was placed between the animal and lower electrode. Our findings corroborated that an EF of 10 kV/m inhibits stress-induced changes in the endocrine system in mice and demonstrated that this effect depends on the configuration of the EF exposure system, even when the EF strength remains the same. Bioelectromagnetics. 38:265-271, 2017.

Characterization of the suppressive effects of extremely-low-frequency electric fields on a stress-induced increase in the plasma glucocorticoid level in mice: Anti-Stress Effects of ELF EF in Mice

We recently suggested that an increase in the plasma glucocorticoid (GC) level in immobilized mice is suppressed by a 50-Hz electric field (EF) in an EF strength-dependent manner. The present study aimed to assess the anti-stress effect of EFs in three scenarios: exposure to an EF of either 50 or 60 Hz, which are the standard power frequencies in most regions; varying levels of environmental brightness during EF exposure; complete or partial shielding of the mouse from the EF. We compared the GC levels and blood parameters among control, EF-alone, immobilization-alone, and co-treatment groups. There was no difference between EFs of 50 and 60 Hz in terms of the suppression of the immobilization-induced increase in GC, that is, the anti-stress effect upon EF exposure. Examination of the effects of three environmental illuminance levels, 0, 200, and 490 lux, revealed that the effect of the EF was influenced by environmental illuminance. Shielding of the mice from the EF by wrapping the animals with an electrically conductive sheet inhibited the EF effect, which showed a negative correlation with the area shielded. Hence, environmental illuminance and the body area exposed to the EF might influence the effects of an EF on stress-induced increases in plasma GC levels in mice. Because stress plays an important role in the onset and progression of various diseases, these findings may have broad implications for understanding the efficacy of EFs in health. Bioelectromagnetics. 39:516-528, 2018

Electric field sensing and imaging by noninvasive parallel-plate sensor

An innovative concept of noninvasive sensor device has been proposed and successfully demonstrated, which makes direction detections and intensity measurements for electric fields be drastically simplified and agile. Its primal feature is a unique geometry, with the simplicity of Columbus’ egg, where an ammeter and optical readout are internally contained in virtual-shorted parallel plates. While its electromagnetic principle for accurate sensing has been confirmed, its function to promptly image directions and distributions of electric fields has been demonstrated combining its aerial scan with a bulb-shuttered photographic camera.

Fine Structures of Epitopic Sites in Human and Bovine Lactoferrin Recognized by Anti-bovine Lactoferrin C-Lobe Monoclonal Antibody

The reactivity towards the monoclonal antibody (MAb) against bovine lactoferrin C-lobe was compared with six members of the transferrin family of proteins by ELISA and dot-blotting methods. This MAb recognizes WNIPMGL (467-473) of the bovine lactoferrin sequence. Human lactoferrin, Korean native goat lactoferrin and bovine transferrin showed weak reactivity with anti-C-lobe MAb. Human transferrin and ovotransferrin did not react with this antibody. As human lactoferrin in the denatured state showed reactivity with the antibody by ELISA, the configurational features of bovine lactoferrin and human lactoferrin were compared. It is observed that human lactoferrin epitopic site is covered with the bulky group and becomes exposed after denaturation.