Biomedical subjects

Da Xing

Publications and source records attributed to Da Xing.

At least 37 records · Page 2Linked to original sources

PubMed2004

[Comparative research on attenuation characteristics of human bladder cancer tissue at different wavelengths of laser and their linearly polarized laser in vitro].

In this paper, a double-integrating-spheres system, the basic principle of measuring technology of ray radiation, and the optical model of biological tissues were used for the study. Attenuation characteristics of human bladder cancer tissue at 467.5, 488, 496.5, 514.5 and 532 nm laser and their linearly polarized laser irradiation were studied. The results of measurement showed that the attenuation characteristics of human bladder cancer tissue in Kubelka-Munk two-flux model were different at different wavelengths of laser irradiation in the range of five different laser wavelengths. There were significant differences in the total attenuation or effective attenuation coefficients of human bladder cancer tissue at 476.5, 496.5, and 532 nm wavelengths of laser and their linearly polarized laser irradiation (P>0.05), and there were no significant differences at 488 and 514.5 nm wavelengths of laser and their linearly polarized laser irradiation in two-flux model (P>0.05). The total attenuation and effective attenuation coefficients of human bladder cancer tissue at 532 nm laser and its linearly polarized laser irradiation were obviously bigger than those at other four different wavelengths of laser and their linearly polarized laser irradiation in two-flux model. The total attenuation and effective attenuation coefficients of human bladder cancer tissue at five different wavelengths of laser and their linearly polarized laser irradiation increased with the decrease of these wavelengths, there were significant differences in those at 476.5, 496.5 and 514.5 nm wavelengths of laser and their linearly polarized laser irradiation (P<0.05), and there were no significant differences in those at 488 and 532 nm wavelengths of laser and their linearly polarized laser irradiation in light transport theory (P>0.05).

Cell Line↗

PubMed2004

[Optical properties of human normal bladder tissue at five different wavelengths of laser and their linearly polarized laser irradiation in vitro].

A double-integrating-spheres system, the basic principle of measuring technology of radiation, and an optical model of biological tissues were used for the study. Optical properties of human normal bladder tissue at 476.5, 488, 496.5, 514.5 and 532 nm of laser and their linearly polarized laser irradiation were studied. The results of measurement showed that total attenuation coefficient and scattering coefficient of human normal bladder tissue at these wavelengths of laser and their linearly polarized laser irradiation increased with decreasing wavelengths. And these was an obvious distinction between the results at these wavelengths of laser and their linearly polarized laser irradiation. Absorption coefficient of human normal bladder tissue at these wavelengths of laser and their linearly polarized laser irradiation was tardily increased with decreasing wavelengths. But there were a number of gurgitations. And these were independent of the wavelengths of laser or their linearly polarized laser irradiation. Mean cosine of scattering of human normal bladder tissue at these wavelengths of laser and their linearly polarized laser irradiation also increased with decreasing wavelengths. And these was an obvious distinction with these wavelengths of laser and their linearly polarized laser irradiation. But penetration depth of human normal bladder tissue at these wavelengths of laser and their linearly polarized laser irradiation also increased with increasing wavelengths. But there were a number of gurgitations. Refractive index of human normal bladder tissue at these wavelengths of laser ranged from 1.37 to 1.44. Absorption coefficient, scattering coefficient, total attenuation coefficient, and effective attenuation coefficients of human normal bladder tissue in Kubelka-Munk two-flux model at the same wavelength of laser and the linearly polarized laser irradiation do not exhibit prominent distinction (P > 0.05). Some absorption coefficient, scattering coefficient, total attenuation coefficient, and effective attenuation coefficient of human normal bladder tissue in Kubelka-Munk two-flux model at different wavelengths of laser and their linearly polarized laser irradiation exhibit obvious distinction.

Humans↗

PubMed2004

[Optical properties of human normal small intestine tissue with theoretical model of optics about biological tissues at Ar+ laser and 532 nm laser and their linearly polarized laser irradiation in vitro].

A double-integrating-spheres system, basic principle of measuring technology of ray radiation, and optical model of biological tissues were used for the study. Optical properties of human normal small intestine tissue at 476.5, 488, 496.5, 514.5 and 532 nm laser and their linearly polarized laser irradiation were studied. The results of measurement showed that the total attenuation coefficient and scattering coefficient of the tissue at these wavelengths of laser and their linearly polarized laser irradiation increased with decreasing wavelengths. And obviously there was a distinction at 514.5 to 532 nm wavelength between lasers and their linearly polarized laser irradiation. Absorption coefficient of tissue at these wavelengths of laser and their linearly polarized laser irradiation increased with decreasing wavelengths. Absorption coefficient of tissue at 514.5 to 532 nm wavelength of laser was obviously decreasing, which was independent of these wavelengths of laser or their linearly polarized laser irradiation. Mean cosine of scattering of tissue at these wavelengths of laser and their linearly polarized laser irradiation also increased with decreasing wavelengths. But penetration depth of tissue at these wavelengths of laser and their linearly polarized laser irradiation also increased with increasing of wavelengths. Refractive index of tissue between these wavelengths of laser was within 1.38 to 1.48. Absorption coefficient, scattering coefficient, total attenuation coefficient, effective attenuation coefficients of tissue in Kubelka-Munk two-flux model at the same wavelength of laser and their linearly polarized laser irradiation showed no prominent distinction (P>0.01). Absorption coefficient, scattering coefficient, total attenuation coefficient, effective attenuation coefficients of tissue in Kubelka-Munk two-flux model at different wavelength of laser and their linearly polarized laser irradiation showed obvious distinction. Optical properties of tissue at 514.5 to 532 nm wavelength of laser exhibited obvious distinction.

Absorption↗

PubMed2004

[Photobleaching properties of GFP expressed in human lung cancer cells].

The characteristic properties of GFP make this protein a good candidate for use as a molecular reporter to monitor patterns of protein localization, gene expression, and intracellular protein trafficking in living cells. In this study, the dicistronic expression vector (pEGFP-C1) was used to be transfected into human lung cancer cell line (ASTC-a-1) and a positive clone which stably expressed GFP in high level was obtained. The results showed that the green fluorescent protein expressed in tumor cells was also photobleached under intense irradiation (-488 nm) and the degree of photobleaching varied with the intensity of the excitation. In order to analyze the effect of low temperature on the fluorescent sample, the photobleaching of tumor cell slice stored at -20 degrees C was observed additionally.

Animals↗

PubMed2003

Enhanced sensitivity and spatial resolution for in vivo imaging with low-level light-emitting probes by use of biocompatible chemical agents.

We describe a technique that uses biocompatible chemical agents to enhance both the sensitivity and the resolution of in vivo imaging with low-level light-emitting probes. We demonstrate experimentally, with chemiluminescence (CL) imaging in vitro as an example, that the detected intensity of CL from treated 3-mm-thick skin tissue is approximately fivefold stronger than that from untreated skin. The spatial resolution correspondingly increases approximately threefold.

Animals↗

PubMed2003

Optical properties of human normal small intestine tissue determined by Kubelka-Munk method in vitro.

AIM: To study the optical properties of human normal small intestine tissue at 476.5 nm, 488 nm, 496.5 nm, 514.5 nm, 532 nm, 808 nm wavelengths of laser irradiation. METHODS: A double-integrating-sphere system, the basic principle of measuring technology of light radiation, and an optical model of biological tissues were used in the study. RESULTS: The results of measurement showed that there were no significant differences in the absorption coefficients of human normal small intestine tissue at 476.5 nm, 488 nm, 496.5 nm laser in the Kubelka-Munk two-flux model (P>0.05). The absorption coefficients of the tissue at 514.5 nm, 532 nm, 808 nm laser irradiation were obviously increased with the decrease of these wavelengths. The scattering coefficients of the tissue at 476.5 nm, 488 nm, 496.5 nm laser irradiation were increased with the decrease of these wavelengths. The scattering coefficients at 496.5 nm, 514.5 nm, 532 nm laser irradiation were obviously increased with the increase of these wavelengths. The scattering coefficient of the tissue at 532 nm laser irradiation was bigger than that at 808 nm. There were no significant differences in the total attenuation coefficient of the tissue at 476.5 nm and 488 nm laser irradiation (P>0.05). The total attenuation coefficient of the tissue at 488 nm, 496.5 nm, 514.5 nm, 532 nm, 808 nm laser irradiation was obviously increased with the decrease of these wavelengths, and their effective attenuation coefficient revealed the same trend. There were no significant differences among the forward scattered photon fluxe, backward scattered photon fluxe, and total scattered photon fluxe of the tissue at 476.5 nm, 488 nm, 496.5 nm laser irradiation. They were all obviously increased with attenuation of tissue thickness. The attenuations of forward and backward scattered photon fluxes, and the total scattered photon fluxe of the tissue at 514.5 nm laser irradiation were slower than those at 476.5 nm, 488 nm, 496.5 nm laser irradiation respectively. The attenuations of forward and backward scattered photon fluxes, and total scattered photon fluxes at 532 nm laser irradiation were obviously slower than those at 476.5 nm, 488 nm, 496.5 nm, 514.5 nm laser irradiation. The attenuations of forward and backward scattered photon fluxes, and total scattered photon fluxe at 808 nm laser irradiation were all obviously slower than those at 476.5 nm, 488 nm, 496.5 nm, 514.5 nm, 532 nm laser irradiation respectively. CONCLUSION: There are significant differences in optical parameters of human normal small intestine tissue in the Kubelka-Munk two-flux model at six different wavelengths of laser radiation. The results would provide a new method of information analysis for clinical diagnosis.

Humans↗

PubMed2003

[The non-trauma fluorescence analysis of the porphyrin in the blood of human superficial skin tissue].

The porphyrin compound in human body mainly includes hemoglobin, protoheme, protoporphyrin, coproporphyrin, uroporphyrin and so on. As we know, the metabolism of the porphyrin in human body depends on the physical conditions. It was found that the relative content of protoporphyrin (PPIX) and carotenoid in blood varied with the developing of the malignant tumor. A system, including Ti: sapphire laser, optical fiber delivery system, fluorescence probe, spectrometer CCD and computer, has been developed to examine the porphyrin in human superficial skin tissue without trauma. It was shown that the fluorescence spectrum of the porphyrin obtained from the superficial skin tissue of human earlobe has the same feature as that from the aqueous solution with PP IX.

Biomarkers, Tumor↗

PubMed2002

Localization of tumor by chemiluminescence probe during photosensitization action.

As a chemiluminescence (CL) probe, 3,7-dihydro-6-[4-[2-(N'-(5-fluoresceinyl) thioureido)ethoxy]phenyl]-2-methylimidazo[1,2-a]pyrazin-3-one dosium salt (FCLA) can sensitively and specifically react with singlet oxygen ((1)O(2)) and superoxide (O(2)(-)). Based on the fact that photosensitization action involves (1)O(2) generation, this report presents a novel method for localization of tumor mediated by FCLA. In experiments, FCLA was used as an optical reporter of (1)O(2) produced from photosensitization reaction of hematoporphyrin derivative. The effects of azide inhibition and deuterium enhancement on photosensitized CL indicated that (1)O(2) molecules generated during photosensitization action could be measured and imaged. In vivo experiments in vivo with tumor-bearing nude mice showed a clear CL image of tumor. The study suggests that CL imaging method may be applicable to the detection of (1)O(2) and the diagnosis of superficial tumors.

Animals↗

PubMed2002

FCLA chemiluminescence from sonodynamic action in vitro and in vivo.

In this work, the chemiluminescence method was engaged for the first time to detect the active oxygen species during sonodynamic action in vitro and in vivo. We used FCLA (3,7-dihydro-6-[4-[2-[N'-(5-fluoresceinyl)thioureido]-ethoxy]phenyl]-2-methylimidazo[1,2-a]pyrazin-3-one sodium salt), which can selectively react with singlet oxygen ((1)O(2)) or superoxide anion (O(2)(-)) to emit photons, to detect in real time oxygen free radical formation in the sonosensitization of hematoporphyrin derivative. The results show that (1)O(2) is involved in the sonosensitization. In in vivo experiments, a tumor-imaging method by sonodynamic chemiluminescence detection was established. This method could have potential applications in clinics for tumor diagnosis.

Fluoresceins↗

PubMed2002

Experimental study on photodynamic diagnosis of cancer mediated by chemiluminescence probe.

A novel method of photodynamic diagnosis of cancer mediated by chemiluminescence probe is presented. The mechanism for photodynamic therapy involves singlet oxygen ((1)O(2)) generated by energy transfer from photosensitizers. (1)O(2) can react with 3,7-dihydro-6-[4-[2-(N'-(5-fluoresceinyl)thioureido)ethoxy]phenyl]-2-methylimidazo[1,2-a]pyrazin-3-one sodium salt (FCLA), which is a Cypridina luciferin analog and a specific chemiluminescence probe for detecting (1)O(2) and superoxide (O(2)(-)). The reaction of FCLA and (1)O(2) can give emission with peak wavelength at about 532 nm. In the present study, FCLA was chosen as an optical reporter of (1)O(2) produced from the photosensitization reaction of hematoporphyrin derivative in model solution and in nude mice with transplanted mammary cancer. Photosensitized chemiluminescence from the reaction of FCLA with (1)O(2) was detected by a highly sensitive Intensified Charge-Coupled Device detector. The chemiluminescence was markedly inhibited by the addition of 10 mmol/l sodium azide (NaN(3)) to the model solution and minor effects were observed at the addition of 10 micromol/l superoxide dismutase, 20 mmol/l mannitol and 100 microg/ml catalase, respectively, thus indicating that (1)O(2) generation from photosensitization reaction mainly results in light emission. Experiments in vivo with tumor-bearing mice showed a clear chemiluminescence image of tumor. The study suggests that this novel method may be applicable to the diagnosis of superficial tumors.

Animals↗

PubMed2002

In vivo sonoluminescence imaging with the assistance of FCLA.

In this paper, sonoluminescence of tissues is reported for the first time. A sonoluminescence image of a living animal was obtained with a high-sensitivity imaging system. Furthermore, to enhance biological sonoluminescence, fluoresceinyl Cypridina luminescent analogue (FCLA), a chemiluminescence analysis agent, was used in the experiment. With the assistance of FCLA we succeeded in observing an image of a living animal with high contrast and good signal-to-noise ratio. This technique has potential applications in clinical diagnosis.

Acoustics↗

PubMed2002

Detection of vitamin C-induced singlet oxygen formation in oxidized LDL using MCLA as a chemiluminescence probe.

In this study, it was observed that addition of vitamin C (vit C) to oxidized low-density lipoprotein (Ox-LDL) by cupric ions (Cu2+) could result in the formation of singlet oxygen (1O2). In experiments, 1O2 was detected by chemiluminescence method using a Cypridina luciferin analog, 2-methyl-6-(p-methoxyphenyl)-3, 7-dihydroimidazo [1, 2-a] pyrazin-3-one (MCLA), as a selective and sensitive chemiluminescence probe. Additional experimental evidence for the formation of 1O2 came from the quenching effect of sodium azide (NaN3) on vit C-induced chemiluminescence in the reaction mixture of LDL-Cu(2+)-MCLA. Analysis based on the experimental results demonstrated the plausible reaction mechanism is that vit C first converts Cu2+ to its reduced state and vit C becomes vit C radical itself, thereby stimulating the formation of peroxyl and alkoxyl radicals, and bimolecular reaction of peroxyl radicals results in 1O2 production in the systems studied.

Ascorbic Acid↗

PubMed2002

[Study of the insoluble remainder of human gallstones by scanning electron microscope and Fourier transform infrared spectrum].

The insoluble remainder of brown pigment and mixed gallstones which were dissolved with chloroform, ethanol, ether, and hydrochloric acid were studied by Fourier transform infrared (FT-IR) spectrum and scanning electron microscope. It was found that bilirubinate salts, proteins, fatty salts, phosphate and calcium carbonate are the main components in the insoluble remainder of gallstones. The secondary structure of proteins in brown pigment gallstones may be predominated by alpha-helix. The microstructure of proteins in brown pigment stones is membranous, phosphate and bilirubinate salts were trapped within the membranes. The relationship between the insoluble components and formation of gallstones was discussed.

Bilirubin↗

PubMedDate not supplied

Rapid determination of rice seed vigour by spontaneous chemiluminescence and singlet oxygen generation during early imbibition.

Using a highly sensitive single photon counter, a spontaneous chemiluminescence (CL) study on rice (Oryza sativa L.) seeds stored in different years was carried out. We first observed that the degree of ageing in rice seeds was related to the intensity of spontaneous CL during early imbibition (0-30 min). Rice seeds stored for a shorter time had a stronger intensity of CL in early imbibition. The germination rate of rice seeds showed an obvious positive correlation with the intensity of spontaneous CL. Singlet oxygen ((1)O(2)) in rice seeds during early imbibition was investigated by a CL method using a cypridina luciferin analogue, 2-methyl-6-(p-methoxyphenyl)-3,7-dihydroimidazo [1,2alpha] pyrazin-3-one (MCLA), as a selective CL probe. Additional experimental evidence for the formation of (1)O(2) came from the quenching effect of sodium azide (NaN(3)) on MCLA-mediated rice seeds' CL. Analysis based on the experimental results demonstrated that spontaneous CL in rice seeds during early imbibition was mainly contributed by singlet oxygen ((1)O(2)).

Germination↗

PubMedDate not supplied

Imaging of ultra-weak bio-chemiluminescence and singlet oxygen generation in germinating soybean in response to wounding.

Ultra-weak bio-chemiluminescence (UBC) from germinating soybean (Glycine max L. Merr) cotyledon under mechanical wounding was observed using a high-sensitivity imaging system based on an ICCD detector and a highly sensitive single photon counter (SPC) device. The UBC imaging showed that the intensity at the injury location on a wounded cotyledon was obviously enhanced as compared with that at the non-injured point. The UBC intensity of wounded cotyledons was initially very high and reached a stationary state after about 5 min. Wounding-induced emission could be suppressed by wounding in the presence of sodium azide. Deuterium oxide amplified the emission intensity. It was concluded that singlet oxygen ((1)O(2)) was the main cause of the emission during the wounding phase.

Cotyledon↗

PubMedDate not supplied

Evaluation of the degree of medical radiation damage with a highly sensitive chemiluminescence method.

A highly sensitive chemiluminescence (CL) method for evaluation of medical radiation damage degree is presented. According to the principle of cell stress response to ionizing radiation, lymphocytes will produce reactive oxygen species (ROS) after irradiation. The ROS produced can react with 2-methyl-6-(p-methoxyphenyl)-3,7-dihydroimidazo[1,2-alpha] pyrazin-3-one (MCLA), a specific CL probe for superoxide anion (O(.-) (2)) and singlet oxygen ((1)O(2)), to emit light at 465 nm. The CL intensity is positively related to the amount of generated ROS detected 30 min after irradiation. Cell viability, which is inversely related to cell mortality, was determined by MTT assay after 3 days' culture. The results show that both CL intensity and cell mortality of lymphocytes increase with the increase of the radiation dose when the dosage is no more than 3 Gy, suggesting a positive relationship between the degree of lymphocyte cell damage and the amount of ROS generated. In addition, the effects of catalase, Cu-Zn superoxide dismutase (SOD), mannitol, sodium azide (NaN(3)), and D(2)O on MCLA-dependent CL of lymphocytes are discussed. We believe that the MCLA-dependent CL method would potentially provide an easy way for evaluating the degree of lymphocyte damage induced by radiation.

Cell Death↗

PubMedDate not supplied

Effects of isoflurane on measurements of delayed lumininescence in Acetabularia acetabulum.

The volatile halogenated methyl ethyl ether, isoflurane, used as an anaesthetic, inhibits actin-based dynamics directly or indirectly in animal cells. In plant cells, most intracellular movements are related to actin pathways. We have used isoflurane in a unicellular alga, Acetabularia acetabulum, to test the dynamics of choloroplast organization. By measuring the delayed luminescence, we found that isoflurane worked efficiently in the unicellular organism and showed dose- and time-course-dependent actin-inhibition patterns. When A. acetabulum was treated with saturated solutions of isoflurane in artificial seawater (defined as 100% isoflurane) for 3 or 6 min, the delayed luminescence (DL) was decreased and was never recovered. In contrast, if treated with 75% diluted isoflurane, the DL was firstly inhibited and then recovered several hours later, and if treated with 50% diluted isoflurane, the change of DL was small. Our work proved that isoflurane can affect actin-related pathways in both animals and plants.

Acetabularia↗

PubMedDate not supplied

Effect of artificial acid rain and SO2 on characteristics of delayed light emission.

The structure and function of chloroplast in plant leaves can be affected by acid rain and air pollution. The photosystem II in a plant is considered the primary site where light-induced delayed light emission (DLE) is produced. With the lamina of zijinghua (Bauhinia variegata L.) and soybean (Glycine max (L.) Merr.) as testing models, we studied the effects of artificial acid rain and SO2 on characteristics of DLE by using a home-made weak luminescence detection system. The results show that the changes in DLE intensity of green plants can reflect the changes in chloroplast intactness and function. With proper calibration, DLE may provide an alternative means of evaluating environmental acid stress on plants. The changes in DLE intensity may provide a new approach for the detection of environmental pollution and its impact on the ecosystem.

Acid Rain↗