Masashi Usa

A novel method of assessing carcinoma cell proliferation by biophoton emission

Changes in the emission intensities of ultraweak biophoton emission during the cell proliferation of human carcinoma cell culture (TE9 cell line) were detected using a highly sensitive and low noise measurement apparatus coupled with a flow culture system. In the sampling period of 93 h, the biophoton emission intensity from the culture followed a similar course as that of the growth curve. Spectral analysis of the biophoton emission from the cell culture demonstrated a significant peak at around 530 nm. Our results suggest that the emission intensity mainly depends on the cell population and that this noninvasive technique has a potential role in cancer diagnosis.

Two-dimensional Imaging of Ultraweak Photon Emission from Germinating Soybean Seedlings with a Highly Sensitive CCD Camera

A novel application of a highly sensitive charge-coupled device (CCD) camera for imaging of spontaneous ultraweak photon emission from living organisms (biophoton emission) is described. The performance of the CCD camera for low-level light imaging is theoretically compared to a conventionally used two-dimensional photon counting tube, and we deduce that in the wavelength region above 700 nm and for measurement periods over 2000 s, the CCD camera is advantageous over the twodimensional photon counting tube. Experimental results on the two-dimensional biophoton imagery of germinating soybean seedlings also suggest that the wide-range spectral sensitivity of the CCD camera is effective for low-level light imaging from living organisms that have a predominant emission spectrum in the red and near-IR wavelength region.

Recent advances in coherent detection imaging (CDI) in biomedicine: laser tomography of human tissues in vivo and in vitro

We review the advantages of the optical heterodyne detection-based coherent detection imaging system, for transillumination laser computed tomography (CT) in biomedicine using CW and single-frequency lasers as light sources. The unique properties of the coherent detection imaging system such as excellent directionality, selectivity, and high sensitivity are exploited to differentiate and detect the minimally deviated on-axis/near-axis photons emerging from a tissue enabling the reconstruction high-resolution laser CT images. Our recent progress on the applications of the coherent detection imaging system to laser CT of human fingers in vivo and calcified tissues in vitro at different wavelengths in the visible and near-infrared regions are described. The laser CT images are obtained with low incident power of a few milliwatts and are comparable to conventional imaging techniques. The internal layers of the imaged tissues could be clearly differentiated and identified with submillimeter resolution. We propose that further refinements in the coherent detection imaging system could lead to a novel and potential diagnostic tool in dentistry, osteology, and bone and joint related diseases and disorders.

Two-dimensional imaging and counting of ultraweak emission patterns from injured plant seedlings

Abstract Two-dimensional emission patterns of ultraweak light originating from physically injured seedlings of soybean and adzuki bean were detected by a two-dimensional photon counting system. From the photon emission patterns, it is possible to determine accurately the wounded regions of the seedlings which exhibit strong emission. Using the same system, the response of injured and intact seedlings to H2O2 was investigated. The addition of H2O2 induces even stronger photon emission from the injured regions. The enhancement of photon emission by the addition of H2O2 appears to be due to two types of response: a fast response in which H2O2 reacts directly and a slow response in which an O2 consumption reaction is involved.

Aldehyde-enhanced photon emission from crude extracts of soybean seedlings

The photon emission from a soybean seedling was remarkably enhanced with the addition of acetaldehyde. The emission spectrum in a seedling had peaks at around 670 and 610–615 nm, with a shoulder at 530–540 nm. In the crude extracts of seedlings, enhancement of photon emission depended on the aldehyde chain length; acetaldehyde gave a maximal photon emission intensity. The photon emission intensity in crude extracts reduced by hydrosulfite showed an initial rapid increase followed by a quick decay in the first phase and a slow decay in the second phase, in the presence of oxygen and aldehyde. The emission spectrum in a whole soybean seedling was observed similarly in crude extracts, with the addition of acetaldehyde. Since a similar photon emission pattern appears in the supernatants of autoclaved extracts, concomitant with the same emission spectra, it is concluded that this photon emission occurs nonenzymatically. Furthermore, when the sample has decayed once photon emission is reduced, the photon emission appears again, upon mixing the sample with oxygen and aldehyde. This result suggests that a hydroperoxide intermediate is an emitter reacting with aldehyde. An energy transfer from triplet carbonyl may not be involved in this reaction.

Chemiluminescence in the crude extracts of soybean seedlings. Postulated mechanism on the formation of hydroperoxide intermediates

It has been reported that weak chemiluminescence (CL) from crude extracts of soybean seedlings is remarkably enhanced with the addition of various aldehydes (Biochim. Biophys. Acta 1058, 209-216). The reactivity of certain emitter(s) with oxygen species was examined in the autoclaved extracts of seedlings. When samples were reduced by the addition of hydrosulfite, two different types of reactivities in CL were defined. One type showed an initial rapid increase and a subsequent fast decay in CL upon mixing with oxygen. This rapid increase in CL intensity was independent of the presence of aldehydes, and was significantly suppressed by SOD. However, the subsequent slow decay phase in CL was dependent on the presence of aldehydes. In the sample reduced more moderately by borohydride, the same slow decay of CL appeared upon mixing with acetaldehyde and oxygen. This second type of CL was not inhibited by active oxygen scavengers. Hydrogen peroxide added to unreduced (oxidized) samples also elicited CL. Three types of primary emitters may be oxidized to form transient hydroperoxide, and excited for light emission by slightly different ways: two of them are excited by abstraction of one atomic oxygen from the hydroperoxy intermediate with aldehyde or hydrogen peroxide, leading to formation of an excited hydroxide intermediate. The third is excited directly on the binding of superoxide anion to the reduced primary emitter.

Spectra of the formaldehyde-induced ultraweak luminescence from yeast cells

An increase in the intensity and distinct spectral changes of ultraweak luminescence from the yeast Saccharomyces cerevisiae were measured when the metabolism of cells was drastically altered. A small emission peak and a red emission band 680-850 nm appeared when air-dried cells were imbibed in water. Lethal concentrations of HCHO (0.01%-10%) elicited a 2500 fold increase of the emission intensity and distinct spectral alterations. A transient 500-580 nm emission appeared in the initial phase of interaction. Then a gradually increasing long-lasting red emission band centered around 620 nm predominated in the total spectral range covering 470-850 nm. These emissions were not correlated with minor changes in fluorescence emission and excitation spectra originating from tryptophan, flavins, and unidentified emitters.

SPECTRAL ANALYSES OF LOW LEVEL CHEMILUMINESCENCE OF A SHORT LIFETIME USING A HIGHLY SENSITIVE POLYCHROMATIC SPECTROMETER INCORPORATING A TWO DIMENSIONAL PHOTON‐COUNTING TYPE DETECTOR

Abstract— Spectral analyses of low level chemiluminescence were carried out by using a newly developed polychromatic spectrometer in which a diffracted photon emission was detected simultaneously using a two dimensional photon‐counting device. The spectrometer was sensitive in the 400–800 nm wavelength range. Low level chemiluminescence generated in a 1 nM luminol solution could be detected as a spectrum, showing a peak at 430 nm. Short lifetime photon emission from singlet oxygen showed only two peaks at around 630 and 700 nm in this highly time‐resolved spectroscopy. Lipid peroxidation of linoleic acid by the lipoxygenase emitted a low intensity peak centered at 440 nm, but singlet oxygen emission arising from the decomposition of lipid peroxide was not observed. An injured cotyledon of a soybean seedling gave a broad emission centered at 725 nm in the absence of hydrogen peroxide, while in its presence a different emission peak appeared at a shorter wavelength (515 nm). Oxygenated, fluorescent components in the soybean seedling may be the emitting species. Singlet oxygen and triplet carbonyl groups were shown to be unlikely sources of the emission.

Laser computed tomography of opaque industrial products measured by coherent detection imaging method

The coherent detection imaging method with a low-power He–Ne laser as the source is used to obtain transillumination laser computed tomographic and two-dimensional (2D) images of opaque industrial products such as fluorescent lamps and electric light bulbs. This method is principally based on the optical heterodyne detection technique that has the highest sensitivity along with excellent selectivity in terms of coherence, polarization and high directionality. Structures of the filament and electrode enclosed in the opaque glass were clearly identified with submillimeter resolution.

Spectroscopic Characteristics of Pulse Blood Flow in the Wavelength Region from Visible Short to Near-Infrared.

Noninvasive techniques for the measurement of biomedical information are the most desirable for diagnostic purposes. The use of optical methods in biomedicine, for example, is rapidly emerging with potential applications. Photo-plethysmography (PPG) is a simple optical technique to examine the state of heart and blood circulating system in situ. Conventionally, wavelength region covering from red to near-IR, commonly referred to as the therapeutic window (600nm-1300nm), have been used for PPG. In the present study, we developed a simple photometer for PPG that used lasers as light sources and compared the pulse blood flow in finger tip at ten different wavelengths from 476.5nm to 820nm. The ratio of the amplitude of ac components to dc components of transmitted light through the tissue was measured as a function of wavelength. Our results suggest that blue and green wavelength regions are also useful for PPG as the red and near-IR regions.