Although Laser Doppler flowmetery (LDF) been extensively used in measurement of microvascular blood flow of different tissues. However, due to some physiological vibrations, fast oscillations of the renal cortical flux (RCF) are hard to be measured. In the study, a commercial 3mW 780nm Laser Doppler flowmetery, with a single fiber and a de-vibration holder, was used to measure the pulsatile RCF in rats. Considering the fast response due to the heart rate of rats, the time constant (TC) was set to 0.05 second and thus the frequency response is up to 20Hz. Furthermore, a calibration standard and a static blood sample were also measured as the references without the pulsatile driving force. In order not to perturb the RCF with tiny momentum, the applying force that the fiber exerted on the renal surface was controlled below 100 dyne. To enhance the signal to noise ratio (SNR), an averaged periodogram was used to estimate the frequency components of the pulsatile microcirculation. It is found that the dominating fast oscillation of RCF is pulsatile and its harmonic components are directly correlated with those of the heartbeat (correlation coefficient =0.999, P<0.001, n=17). The result shows that, in the kidney, the pulsatile RCF is the dominating component of microcirculation oscillation and driven by the fast propagating blood pressure. This technique could be further utilized to analyze the pharmacological effect and hemodynamic parameters on renal function.

Films made from genetically modified bacteriorhodopsins (BR) are attractive media for holographic recording. A holographic camera system is presented which uses BR-films as photowritable-photoerasable optical recording media. This camera system is useful in applications like non-destructive testing, vibration analysis and size measurement. To our knowledge this is the first technical system were a biological material, the BR-films, are employed as a performance determining component. The camera head is dust proof sealed and internally damped for applications in a technical environment. All control and display devices are mounted in a separate 19' rack which comes with the system. The system can be easily switched between various holographic measurement techniques under software control, among them double-exposure, time-averaging, real-time and phase-shifting interferometry. The system is able to resolve deformations with a resolution down to 5 nm ((lambda) /100) and operates at 12 frames/second. A variable read-out magnification allows to take advantage of the very high resolution of the BR-films which is beyond 5000 lines/mm. Polarization recording in BR-films is employed to obtain a high signal-to-noise ratio even at low exposures of 100 (mu) J/cm². The recording mechanism at low light levels is discussed in detail.

In this work a new approach based on the fiber Optic Evanescent Wave (FOEW) Spectroscopy is developed for the effective determination of dental caries activity in human saliva. The biosensor design utilized the exponentially decaying wave that extends to the lower index region of the optical fiber's core-cladding interface. In order to achieve this, a short length of the cladding is removed and the fiber core surface is coated with a porous glass medium using sol-gel technique. The acidogenic profile resulting from the Streptococcus mutans activity in the human saliva is monitored using an indicator, which was encapsulated within the porous coating. These investigations display the potential benefits of FOEW based microbial sensor to monitor caries activity in human saliva.

In the past decade several studies have demonstrated the increased acid resistance in enamel demineralization after laser irradiation. However, the exact mechanism of action to this effect still remains a speculation. Recently, the role of organic matrix was revealed to be significant in the laser-induced inhibition of enamel demineralization. The aim of the present study was to characterize the lipid component of organic matrix in mature lazed enamel and unlazed enamel histochemically using a hydrophobic fluorescent probe with Confocal Laser Scanning Microscope (CLSM). Partial decalcification of thin enamel sections was carried out using 0.5 M of EDTA in a stainless steel grid for 5 hours, following fixation with 3.5% paraformaldehyde. Thereafter the sections were stained with Nile red coupled with CLSM. The intensity of the light reflection was analyzed under the same conditions for all specimens, ruling out the autofluorescence in the control sections. Confocal imaging revealed a diffuse and increased fluorescence of the lipid stain in the lazed areas suggesting that the swelling and coating of organic matrix on the surface of enamel crystals in the peri and interprismatic spaces is rendering the increased acid resistance. These findings will substantiate the proposed organic blocking theory in partially explaining the laser-induced prevention of enamel demineralization.

A light beam coming from a circularly polarized heterodyne light source passes through a chiral medium, its rotation angle is just half of the phase difference between p- and s- polarization components. And this phase difference can be measured accurately with heterodyne interferometric technique. The rotatory power is obtained by dividing the estimated rotation angle with its path length. This method has many advantages, such as, high stability, high resolution, easy operation, and real-time measurement.

In the paper the research status and viewpoints about the coherent of the ultra-weak photon emission from biological system (UPE) were simply introduced. For proving the biophotons indeed have coherent from another side, an experimental setup for testing UPE in different spectral region was designed. Using the experimental setup the test data of different several spectral regions from 300nm to 1060nm has been got. These test results show that UPE of living biological system exists in wide spectra region from UV-visible to infrared. Using the test data, we also can obtain the important conclusion of UPE has coherence. In the end of this paper, the UPE's application in medicine was discussed.

In this work, chemiluminescence method was engaged for the first time to detect the active oxygen spices during sonocynamic action both in vitro and in vivo. We used CLA derivatives, which can efficiently react with singlet oxygen (¹O₂) or superoxide anion (O₂^-) to emit light, and luminol, which can be oxidized by a variety of free radicals to emit photons, to real-timely detect oxygen free radical formation in the sonosensitization of two sonosensitizer ATX-70 and HpD. The results show that ¹O₂ is involved in the sonosensitization. The mechanism of sonosensitizing was discussed. In vivo experiments, tumor imaging by sonodynamic chemiluminescence detection methods was established. This method could have potential applications in clinics for early-stage tumor diagnosis.

In this paper, spectrospopic feature of photo-induced acoustic signal generated in biological tissues are investigated, and its characteristics are analyzed in time domain and in frequency domain. The results show that spectrum of photoacoustic signal changes with the property of medium sensitively. The frequency range of photoacoustic signal generated in biological tissues is about 2MHz, and its time duration is about 2microsecond(s) . According to the characteristics of photoacoustic signal, we present an experiment result of a photoacoustic tomography to depths of ~7mm for a real tissue, using a 532-nm pulse YAG laser. The time-resolved stress detection technique was used for PA signal detection and a spatial resolution up to 0.1mm was obtained. A phase-controlled focus algorithm was used for image reconstruction. Images of different depth profile of tissue was obtained with a depth resolution of ~20micrometers .

The proposed new method solves the problem that it is difficult to obtain high-resolution simultaneously in both x and y direction for an ultrasound -modulated optical tomographic 2-D image. In this method, incident laser and detector are coaxial to utilize the character of small lateral size of ultrasonic focused zone. An 860nm, 20mW laser is delivered by a fiber that passes the hole in the center of ultrasound transducer. It illuminated to a 20mm thick fat tissue with a buried object, a 5mm-wide colloidal cube, meanwhile ultrasound is focused to the sample. The scattering modulated photons are collected by an avalanche diode module, and then output signal is amplified and inputted to an oscilloscope with a FFT module. A 3D translation stage carried the sample moving to complete scanning. Combing with frequency swept ultrasound technology, the 2D tomographic images of different depth are obtained.

The refractive index matching (immersion) method is used to enhance the optical penetration depth of whole blood in in vitro study by the NIR optical coherence tomography (OCT) technique. It was found that for tested agents (glucose, dextrans, propylene glycol, and trazograph) the enhancement of penetration was from 20 % to 150 %. In the blood sedimentation study, regular or irregular oscillations or jumps of the RBC/plasma boundary were observed. The one-minute time period of regular oscillations correlated well with the kinetics of the aggregation process. For the first time OCT images of blood aggregates in a small plastic vessel were observed. Presented results have potentials in intra-vascular OCT imaging and in blood sedimentation and aggregation studies for diagnostic purposes.

Sol-gel technique is a method for producing of glass-like materials without involving a melting process. Organic compounds such as alcoholates of silicon, sodium or calcium can be used. The irregular non-crystalline network forms a gel structure where the metallic atoms are bonded to oxygen atoms. Low-temperature treatment turns this gel into an inorganic glass-like structure. There are numbers of applications of these materials that can be produced in various forms and shapes. Here, silica based sol-gel bulks and thin films optodes for biomedical applications will be presented.

Recently, the sol-gel based biomaterials are extendedly investigated with emphasis on theirs various applications, including medical ones. In this respect it is important to investigate the influence of sol-gel matrices on biological systems. The results of laboratory and biological testing of aqueous extracts of sol-gels are presented in this work. It was proved that it is possible to produce the sol-gel derived materials that will be non-haemolytic. This can be achieved by heating the materials in elevated temperatures. This effect can also be reached by suitably long aging (minimum 6 months).

For the evaluation of the therapy effects the double-blind clinical trial followed by statistical analysis was performed. After statistical calculations it was stated that laser therapy with IR radiation has a significant influence on the decrease of the level of pain in the examined group of patients suffering from various locomotive diseases. The level of pain of patients undergoing laser therapy was statistically lower than the level of pain of patients undergoing placebo therapy. It means that laser therapy had statistically significant influence on the decrease of the level of pain. The same tests were performed for evaluation of movement range. Although placebo therapy contributes to the increase of the range of movement, the statistically significant influence was stated in case of the therapeutic group treated by laser.

The infrared emitting lasers have been widely used in medicine. The aim of this work was to examine the IR laser light evoked changes in the breast carcinoma of rats. The different light doses were applied: 1J/cm², 10J/cm², 20J/cm² and 30J/cm². The used wavelength was 980nm. The tumors were irradiated for 10 days. There was also control (non-irradiated) group. In both groups, no additional pharmacological means were applied. The bigger increase of the tumor size was stated in case of lowest mentioned here light dose. In this case the severe metastasis to the lung and lymphatic nodes were noticed. No metastasis were observed in case of highest dose applied in this study. For higher energy densities an apoptosis in tumors was stated.

The work is devoted to an analysis of pre-clinical and clinical experiments on photodynamic action of HeNe laser radiation in aggregate with a cation thiazinium dye Methylene Blue (MB) on a mix of pathogenic and conditionally pathogenic aerobic bacteria being activators of pyoinflammatory diseases of oral cavity. Concentration of photosensitizes at which there is no own bactericidal influence on dying microflora, and parameters of influence at which the efficiency of irradiated microflora defeat reaches 99% are determined.

A portable and rapid near-infrared (NIR) Raman spectroscopy system together with a tissue Raman probe was developed and utilized to acquire in vivo skin Raman spectra at 785 nm excitation. We demonstrated that good quality in vivo skin Raman spectra free of interferences of fiber fluorescence and silica Raman signals can be acquired within 5 seconds. Distinct Raman peaks in the 800-1800 cm^-1 range can be discerned clearly from various skin sites of the body. The intensity ratio of the Raman band at 1655 cm^-1 to that at 1445 cm^-1 was used to evaluate the variation of the protein/lipid depositions in the skin. The results show that the regional variations in the molecular composition and structure can be determined in vivo, suggesting that NIR Raman spectroscopy will be useful to non-invasively measure important biochemical parameters of human skin.

A study on in vivo measurement of autofluorescence spectra for hamster buccal pouch and development of oral carcinogenesis identification algorithm is presented. The measurement was preceded with a fiber-optics based fluorescence spectroscopy system. In total 75 samples, including 14 hyperkratosis, 23 normal, 28 dysplasia, and 10 SCC, were separated into 4 categories. All the spectra were normalized to have the same area below the spectrum curve. The results show that the autofluorescence spectra start to change as soon as the tissues have morphological alternation (eg hyperkratosis). The differences of ratios between the areas under 380+/- 15 nm and 460+/- 15 nm (denoted as A_{380+/- 15}/ A_{460+/- 15}) among categories are statistically significant. To develop a diagnostic algorithm for early neoplasia detection and evaluate its performance, a PLS discriminant analysis with cross-validation technique was proceeded. Sample points on the PLS score plot were grouped as four categories. By selecting suitable threshold, the accuracy rates for classifying 4 categories of samples are 86% (hyperkratosis), 87% (normal), 90% (dysplasia), and 100% (SCC), respectively. The results reveal that the autofluorescence spectroscopy technique is potential for in vivo detection of early neoplasia of oral tissues.

Optical imaging with a high detecting power is very instrumental to dynamic observations of bio-molecular objects in water. To pioneer this field of imaging researches further, we used novel objective lenses of 1.65 and 1.45 in NA comparatively with 1.35 NA lens. The lenses of ultra high NA have a high resolving power and very useful properties for observation of high contrast images of fluorescently labeled molecules and subcellular organelles including DNA and membrane fusion proteins.

A digitized fluorescence endoscopy imaging system combined with 5-Aminolevulinic Acid (5-ALA) induced Protoporphyrin IX (PPIX) has been developed for the detection of neoplasms in oral cavity. It mainly consists of the illumination console, fluorescence detection unit, computer system for image acquisition, processing and analysis, and online image display system as well. The developed system can produce both the digital and video fluorescence images in real time, and can be used to quantify fluorescence images acquired. Preliminary results from the Head and Neck clinic show that high sensitivity and high specificity can be achieved. Furthermore, applying the intensity ratios at two different wavelength regions, the developed system shows the capability of differentiating between different histopathological stages of oral lesions, suggesting a significant potential for realizing the non-invasive optical biopsy for early cancer diagnosis.

Fluorescence excitation-emission matrices (EEMs) were measured from normal and tumourous oral tissues in vitro using excitation wavelengths ranging from 220 to 500 nm. The prominent fluorescence excitation-emission peaks: (228 nm; 260/338/475 nm), (282 nm; 337/475/660 nm), (335 nm; 472 nm) and (465 nm, 523 nm) for normal tissues; (228 nm; 335/475/660 nm), (282 nm; 330/660 nm) and (350 nm; 460 nm) for tumour tissues, can be found in EEM maps, indicating the dominant fluorophores responsible for tissue autofluorescence are tryptophan, NADH, FAD, and porphyrin compounds in oral tissues. The optimal excitation wavelengths were found to be 280, 335, and 465 nm. The empirical discrimination algorithms based on I₄₇₅/I₆₆₀, and I₅₂₀/I₆₆₀ were developed. These algorithms yield an average sensitivity and specificity of 95% and 88%, respectively.

The ratio of autofluorescence intensity at 550+/- 10 nm to that at 630+/- 10 nm (R₁=I₅₅₀/I₆₃₀) or 680+/- 10 nm (R₂=I₅₅₀/I₆₈₀) was used as a diagnostic algorithm for identification of malignant tumour tissues. The performance of the ratio diagnostic algorithm was evaluated on more than 100 human colonic specimens under excitation laser light at 457.9 nm. A significant difference of the ratio value R₁ and R₂ was found between normal and tumour specimens (p<0.001). The diagnostic test has a sensitivity and specificity of 85% and 87% for a threshold value of R₁=1.75, and a sensitivity and specificity of 94% and 82% for a threshold of R₂=3.5. The experimental results show that the ratio mapping is sensitive to the small changes in the presence of tumour tissues, and the contrast of the contour map for detecting the region of malignancy can also be enhanced significantly if using the diagnostic algorithm R₂ (I₅₅₀/I₆₈₀).

A generalized m-line spectroscopy enables an evaluation of the parameters (the refractive index, n and the thickness, W) of sub-guiding films deposited on a planar waveguide. The method is based on a coupling of a laser beam with a prism coupler and studying of light distribution of the beam decoupled by the same prism. Additionally to the beam spot reflected geometrically from the prism base the light distribution takes a form of discrete lines - m-modes. This image can be observed but only for some discrete values of the coupling angles. The refractive index, n and thickness, W of the waveguide are evaluated by the numerical solution of the dispersion equation with a set of the coupling angles. A sub-guiding film (not reaching the guiding effect) when deposited on the existing planar waveguide influences the present guiding system and effects its guiding properties. From the previous and actual coupling angles the thin film parameters can be evaluated. In the paper an application of the generalized m-line spectroscopy to biological samples is presented. Some initial measurements reveal an effect of the presence of the films on the coupling angles of the structures. The presence of glucose has been revealed in secretions of patients suffering diabetes. Testing of its presence with proposed method can be performed with a trace amount of the patient secretion.

A fiber optic microsensor is described which utilizes the surface plasmon resonance (SPR) effect to detect the chemical environment surrounding the fiber. The sensor is a multimode step index optic fiber, which is constructed by removing the fiber cladding layer with hot sulfuric acid and coated with gold film on fiber core and on distal end. The changes in the light reflectivity are recorded as SPR spectra, which are highly sensitive to the optical properties of the samples adjacent to the sensor surface. The incident light is guided through a splitter to excite and record SPR in both visible and near infrared (NIR) regions. The NIR spectrum has a larger and sharper resonant peak than visible one. It thus provides a more sensitive mechanism to probe the vicinity of interface for biochip applications.