low-cost-electroencephalographic-recording-system-combined-with

Low-Cost Electroencephalographic Recording System Combined with a Millimeter-Sized Coil to Transcranially Stimulate the Mouse Brain <em>In Vivo</em>

A low-cost electroencephalographic (EEG) recording system is proposed here to drive transcranial magnetic stimulation (TMS) of the mouse brain in vivo, ...

Hokkaido University

A highly sensitive ATP bioluminescence assay with diethylaminoethyl-dextran (DEAE-Dx) in the presence of ATP extractants such as trichloroacetic acid (TCA) and Triton X-100 is described. These ATP extractants inhibited the activity of firefly luciferase, resulting in a remarkable decrease in the intensity of light emission. However, DEAE-Dx enhanced the intensity of light emission as long as firefly luciferase was active in the presence of the ATP extractants. When DEAE-Dx was used for the assay, the detection limits for ATP in the presence of TCA and Triton X-100 were 0.3 and 0.5 pM, respectively, in aqueous ATP standard solution. The detection limit in the presence of DEAE-Dx was improved 13- to 20-fold compared to that in the absence of DEAE-Dx. The method was applied to the determination of ATP in Escherichia coli extracts. When a 5% solution of TCA was used for the extraction of ATP from E. coli cells, the detection limit corresponded to 250 cells ml(-1) of E. coli.

Enhanced firefly bioluminescence assay of ATP in the presence of ATP extractants by using diethylaminoethyl-dextran.

Firefly bioluminescence assay of ATP using diethylaminoethyl-dextran as an enhancer in the presence of sodium chloride and ATP extranctant.

In micro total analysis systems, liquid chromatography (LC) works under pressure-driven flow is the essential analysis component. There were not, however, much works on microchip LC. Here we developed a microchip for reversed-phase LC using porous monolithic silica. The chip consisted of a double T-shaped injector and a approximately 40-cm serpentine separation channel. The octadecyl-modified monolithic silica was prepared in the specified part of the channel on the microchip using sol-gel process. Furthermore, the effect of geometry of turn sections on band dispersion at turns was examined under pressure-driven flow. High separation efficiencies of 15,000-18,000 plates/m for catechins were obtained using the LC chip.

Reversed-phase liquid chromatography on a microchip with sample injector and monolithic silica column.

Transcranial magnetic stimulation (TMS), a minimally/non-invasive method of electromagnetic stimulation of brain tissue, has been shown to be beneficial in clinical therapy for specific neurological diseases and disorders. Magnetic stimulation is also used to modulate human and animal brain activity in basic neuroscience studies. Among experimental animal models, mouse models are particularly popular and uniquely representative of brain disorders in basic neuroscience research. TMS in mouse models may play a substantial role in understanding TMS-induced changes in neural networks and plasticity. Although TMS techniques are widely used to examine rodent disease models, techniques specific for mice using small magnetic stimulators have not been intensively developed. Here, we provide a numerical simulation and a practical method of applying TMS to mice by constructing millimeter-sized TMS coils to deliver a low stimulation intensity while maintaining focality. Our results indicate the TMS coils can produce an electrical field with sufficient magnitude to activate the anesthetized mouse cortex in the presence or absence of the skull in vivo. Our results also show that, immediately after magnetic stimulation, local field and action potentials were reliably observed in a manner that depended on the distance between the coil and the brain, implying even a small coil could reliably evoke cortical activity. Therefore, our results show our millimeter-sized coils could produce electric fields sufficient to alter cortical excitability in mice. These coils could be useful in future preclinical studies to examine detailed mechanisms underlying TMS-induced changes in neural activity of the auditory cortex and other cortical regions.

Article	Year
Enhanced firefly bioluminescence assay of ATP in the presence of ATP extractants by using diethylaminoethyl-dextran. Analytical biochemistry\| PubMed ID: 12054452	2002
Firefly bioluminescence assay of ATP using diethylaminoethyl-dextran as an enhancer in the presence of sodium chloride and ATP extranctant. Analytical biochemistry\| PubMed ID: 12694735	2003
Reversed-phase liquid chromatography on a microchip with sample injector and monolithic silica column. Journal of chromatography. A\| PubMed ID: 16876806	2006
Temporal and spatial profiles of evoked activity induced by magnetic stimulation using millimeter-sized coils in the mouse auditory cortex in vivo. Brain research\| PubMed ID: 36115587	2022

Takahiro Yoshikawa

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