A theory is presented that allows for the prediction of the power of the photocurrent fluctuations in laser Doppler blood flowmetry (LDBFM). The method is complementary to the Monte Carlo simulation method which is only capable of predicting the shape of the Doppler spectrum. The input data required for application of the theory are the angular distribution of the detected photons and the relative amount of Doppler shifted photons. The consequences of the speckle dynamics for the various modes of LDBFM are discussed. The speckle behavior is particularly important in those cases where the photodetector is directly exposed to the light scattered back from the tissue, as found in a certain setup of laser Doppler imaging (LDI). In that case, the optical properties of the tissue govern the size of the speckles. Hence, the type of tissue affects the instrumental response through the speckles in an independent way. In this paper, this effect has been quantified for a number of typical tissues. The speckle effect not only influences the overall response of the instrument in a strong manner, but also its sensitivity to motion at various depths. The speckle related variation of the instrumental response may be suppressed when a sufficiently wide beam is used.

A new optical tissue phantom is presented, which consists of a polymer film containing scatterers and absorbers. With this tissue phantom, tissue models can be constructed having optical properties and layered structures similar to those in living tissue. Optical properties can be specified for each layer, with a resolution of 20 micrometers. With this tissue phantom, a new laser Doppler testing principle is developed using a repetitive construction of static and moving layers. In this paper, the consequences of the usage of uniform motion in thin layers are discussed, as compared with the more random motion of blood in tissue. This issue is studied by means of Monte Carlo simulations. Measurements are shown performed with a laser Doppler imager. In particular, the normalization of the flux signal is discussed. It turns out, that normalization with the DC-level of the backscattered light gives better images than normalization with DC². Also, results of depth sensitivity measurements are shown.

LASCA is a single-exposure, full-field technique for mapping flow velocities. The motion of the particles in a fluid flow causes fluctuations in the speckle patten produced when laser light is scattered by the particles. The frequency of these intensity fluctuations increases with increasing velocity. These intensity fluctuations blur the speckle pattern and hence reduce its contrast. With a suitable integration time for the exposure, velocity can be mapped as speckle contrast. The equipment required is very simple. A CCD camera and a framegrabber capture an image of the area of interest. The local speckle contrast is computed and used to produce a false-color map of velocities. LASCA can be used to map capillary blood flow. The results are similar to those obtained by the scanning laser Doppler technique, but are obtained without the need to scan. This reduces the time needed for capturing the image from several minutes to a fraction of a second, already a clinical advantage. Until recently, however, processing the captured image did take several minutes. Improvements in the software have now reduced the processing tome to one second, thus providing a truly real-time method for obtaining a map of capillary blood flow.

A method is described for measuring the retinal vessel diameter in bio-speckle flowmetry. Knowledge of the vessel diameter is required not only to calibrate the correlation time in velocity in the bio-speckle method, but also to evaluate a blood flow-volume rate. One-dimensional fundus reflectance patterns are detected across the retinal vessel by using a linear image sensor on the basis of spectral reflectance properties, and are used to determine the vessel diameter by using a signal processing. A total apparatus was constructed to measure simultaneously the vessel diameter and the correlation time and, thus, the flow velocity and the flow volume rate. The usefulness of the method was verified by in vivo experiments.

An attempt was made at determining if the elastically backscattered Doppler shifted light from cutaneous blood vessels merely emanates from the peripheral parts, or also from the more central core of these vessels, after illumination by red laser light (632 nm). A multilayered, semi-infinite Monte Carlo model of human skin was constructed accordingly, with separate layers or epidermis, dermis including blood, inferior vascular plexus and subcutaneous fat. Two concentric cylinders of infinite length and with varying diameters, representing core and peripheral parts of a blood vessel, were located at various depths in the skin model, either in the superior or inferior vascular plexus. In order to test the stability of the model predictions, widely varying values of the optical properties were employed in the calculations, trying to encompass most of the extreme values found in the literature. The number of photons Doppler shifted by a fixed size central core of a small blood vessel, is independent of the volume of blood surrounding this core in the rest of the blood vessel, provided the total number of detected photons is maintained constant, and the vessel dimensions are within human physiological limits. For the source/detector system simulated (one optical fiber 700 micrometer diameter), backscattered light Doppler shifted in superficial blood vessels constituted almost all the photons detected, with only very few photons having interacted with the inferior plexus.

Measurement of erythrocyte sedimentation rate (ESR) is one of the most widely used diagnosis techniques. It is believed that high ESR testifies to inflammatory conditions or decay in body tissues. However, standard ESR test data do not allow definitive determination of such conditions. ESR is currently determined manually. The ambiguity of standard ESR tests that have found general use in medicine raises the necessity of increasing their information merit without serious modification to the test method. The present device and method allow completely automatic hourly ESR measurement and determine several parameters of blood sedimentation dynamics (BSD). Analysis of BSD introduces a number of parameters that allow pathology to be detected in case of normal standard ESR test data and allow more efficient planning of medical treatment than is available with hourly ESR data. The results were used to elaborate and produce a pilot device for automatic clinical ESR testing to obtain BSD data. The device and BSD method are being clinically tested at the Intensive Care Unit of the Moscow Central Railway Hospital. All the technical solutions have been patented. BSD can be applied as a new powerful diagnostic tool, once large statistics has been obtained.

It is well accepted, that in whole blood as well as in blood suspensions light transmission increases, when shear stress is applied. Up to now it is not clear to what extent the changes in forward scattering are related to the orientation of the RBC in flow or to their elongation. If the latter would be true, forward scattering could be used as a simple parameter for RBC deformability. For our present investigation we used the method of laser diffraction in combination with image analysis to determine RBC elongation. Simultaneously forward scattering was measured by a photo detector, placed in the center of the non-diffracted laser beam. When slowly increasing the shear stress from 0 - 500 dyn/cm² the light intensity measured by the photo detector first increased steeply, reaching a maximum of transmission at about 25 dyn/cm², followed by a mono-exponential (elongation related) decay, reaching a 'steady state' at shear stresses producing maximum elongation (450 - 500 dyn/cm²). But, the decrease of transmission was only present, if the hematocrit (HCT) of the sample was greater than 0.5%. At a HCT less than or equal to 0.5%, only an exponential increase of transmission was detected, reaching a 'steady state' at about 25 dyn/cm². In the apparatus used, the orientation of RBC is complete, if a shear stress of 15 to 25 dyn/cm² is applied. Hence, at low shear stresses the increase of transmission is a consequence of RBC orientation. At low HCT, RBC-elongation (due to shear stresses between 25 - 500 dyn/cm²) does not influence forward scattering. The elongation related decrease of light transmission observed at high HCT (1% - 6%) may be explained by an increase of the area of deformed RBC, promoting the formation of additional cell layers. As a consequence multiple scattering will reduce transmission. Alternatively, during RBC-elongation the cross section of interaction, comprising absorption and scattering, may be altered.

Dynamic light scattering (DLS) measurements are mostly performed in dark rooms. Flare and external lights must be avoided in the design of such systems. Recent advancements in optoelectronic devices and fiber optic technology has opened up applications of DLS in areas where a few years ago, their use could not be imagined. We present a compact and flexible fiber optic DLS system with optical viewing (imaging) capability to monitor biological fluids and tissues in-vivo or in-situ in real time. The optical port requires white light illumination for sample viewing or video linking. An evaluation of the effects of mixing white illumination photons with launched coherent (red) photons on the DLS data will be made. Effects such as spatial coherence factors and the reliability in determining accurate particle size from such measurements are evaluated.

The reproducible models of biomedical optics, the measurements of chemical compounds, the aggregations of particles and so on require the statistical space-time properties of the multiply scattered light in laboratories to be analyzed quantitatively. A cluster-cluster structure in fractal media is replaced with a polydisperse random medium by renormalizing a cluster to a particle. As the particle size-distributions, a simple summation of particles with two radii, a Gaussian function and a power law function were used in numerical simulations. The light scattered from particles inside a cluster affects a decreasing rate of the backscattering intensity cone but not a relaxation time of autocorrelation functions of the time- varying intensity. On the contrary, the movement of the cluster affects strongly the relaxation time through the diffusion constant but not a decreasing rate of the backscattering intensity enhancement. As a result, it is concluded that the temporal autocorrelation functions of the time-varying light intensity scattered multiply from the cluster-cluster structure are applicable to measure the averaged cluster size of aggregations.

Dynamics and light-scattering properties of the Brownian particles in colloidal suspensions under an influence of the radiation pressure force of an illuminating laser beam are investigated by means of computer simulations using the Fokker-Planck equation and the generalized Lorenz-Mie theory. Dynamic behavior of the particles and a temporal correlation function of intensity fluctuations of the light scattered by these particles are calculated for various factors of particle size and power of the illuminating laser beam. Results of the simulations support the experimental observations of deformations in the temporal correlation functions of the scattered light and their dependencies on a size of the particles and a power of the laser. From simulation results of the dynamics of particles, it is found that these changes in the correlation function come from suppression in the radial direction of the laser beam and an acceleration in the axial direction of the beam, of a random motion of the particles.

Laser induced surface second harmonic generation (SSHG) has been applied to study the nature of oligonucletides on glass surfaces. A very strong SSH signal from most of the investigated oligonucletides was observed. The oligonucleotides were found to be resistant to damage from the incident laser radiation, up to peak pulse powers 8MW. The surface second harmonic signal intensity has been shown to be strongly dependent on the angle of the incident laser beam with respect to the sample surface. The study of both angle and polarization dependencies of glass surfaces coated with 12 mer oligonucletide AAAAAATTTTTT and fluorescein fTTTTTTTTTTTT labelled 12 mer oligonucletide is reported. The SSHG technique has been used for quantitative measurements to determine the surface concentration of several oligonucletide samples. The measured surface concentration dependence offers the potential for the development of oligonucleotide assays based on surface second harmonic generation.

In this investigation an attempt is made to find the effects of controlled breathing on brain with the help of optical sensors mounted on the left and right temples of a subject. It has already been established that the brain activity can be monitored in terms of arterial blood volumetric changes to the left and right hemispheres of the brain recorded with the help of optical sensors. To investigate the influence of controlled breathing, an expert in controlled breathing (pranayama) is chosen as the subject. Pranayama is believed to be the controlled intake and outflow of breath in a firmly established posture. Some types of pranayama are believed to relive mental stress. While the subject is practicing one such type of breath control, arterial blood volume changes in the brain are recorded using optical sensors mounted on the left and right temples of the subject. From these measurements at the beginning and end of the pranayama exercise, it could be noticed that the subject could induce changes in the cardiac and respiratory rhythms by controlled breathing. Rhythmic phenomena in the skin perfusion in the vicinity of the brian are also studied when the subject is holding his breath. The arterial blood volume changes to the left and right hemispheres of the brain, as monitored by the optical sensors during this period, exhibit asymmetric reaction when the subject is holding his breath. An attempt is made to understand whether these changes induced by stoppage of breathing are 'chaotic' or 'adaptive' in nature.

We report the results of an in-vitro study on autofluorescence from pathologically characterized normal and malignant squamous tissues from the oral cavity. The study involved biopsy samples from 47 patients with oral cancer of which 11 patients had cancer of tongue, 17 of buccal mucosa and 19 of alveolus. The results of excitation and emission spectroscopy at several wavelengths (280 nm less than or equal to (lambda) _exless than or equal to 460 nm; 340 nm less than or equal to (lambda) _em less than or equal to 520 nm) showed that at (lambda) _ex equals 337 nm and 400 nm the mean value for the spectrally integrated fluorescence intensity [(Sigma) _(lambda ) I_F((lambda) )] from the normal tissue sites was about a factor of 2 larger than that from the malignant tissue sites. At other excitation wavelengths the difference in (Sigma) _(lambda ) I_F((lambda) ) was not statistically significant. Similarly, for (lambda) _em equals 390 nm and 460 nm, the intensity of the 340 nm band of the excitation spectra from normal tissues was observed to be a factor of 2 larger than that from malignant tissues. Analysis of these results suggests that NADH concentration is higher in normal oral tissues compared to the malignant. This contrasts with our earlier observation of an reduced NADH concentration in normal sites of breast tissues vis a vis malignant sites. For the 337 nm excited emission spectra a 10-variable MVLR score (using (Sigma) _(lambda ) I_F((lambda) ) and normalized intensities at nine wavelengths as input parameters) provided a sensitivity and specificity of 95.7% and 93.1% over the sample size investigated.

We report, to our knowledge, the first use of synchronous luminescence (SL) spectroscopy for autofluorescence diagnosis of cancer. The spectral narrowing effect of the SL spectroscopy led to an easier identification of the different fluorophores present in human breast tissues and provided relative estimate of their concentration in qualitative agreement with the estimates obtained from conventional excitation and emission spectroscopy. Further, the SL spectra from human breast tissues could discriminate cancerous tissues from benign tumors and normal tissues with a sensitivity and specificity of 100% in a study involving 34 patients with breast tumor (19 ductal carcinomas and 15 fibroadenomas).

A non-invasive in vivo fluorescence detection scheme was employed to continuously monitor exogenous dye clearance from the vasculature. Differentiation between normal and abnormal organ function in a rat model was demonstrated for both liver and kidney. A fiber optic transmitted excitation light from source to ear; a second fiber optic positioned near the ear transmitted the emitted fluorescent light to a detector system. Several dyes were employed in the initial feasibility studies. Indocyanine green, known to be exclusively cleared from the blood stream by the liver, was excited in vivo with laser light at 780 nm. The fluorescence signal was detected at 830 nm. Characteristic clearance curves of normal hepatic function were obtained, with decay rates that agreed well with literature values. After surgically performing a partial hepatectomy, clearance curves with greatly reduced decay rates were obtained as expected. Additionally, fluorescein labeled polymers and peptides were excited in vivo with laser light at 488 nm. The fluorescence signal was detected at 520 nm. Characteristic clearance curves of normal renal function were subsequently obtained. Thus, the feasibility of a new non- invasive method for physiological function assessment was established.

Nonenzymatic glycation of free or peptide bound amino acids (Maillard reaction, MR) plays an important role in aging, diabetic complications and atherosclerosis. MR taking place at high temperatures is accompanied by chemiluminescence (CL). Here kinetics of CL development in MR proceeding in model systems at room temperature has been analyzed for the first time. Brief heating of glycine and D-glucose solutions to t greater than 93 degrees Celsius results in their browning and appearance of fluorescencent properties. Developed In solutions rapidly cooled down to 20 degrees Celsius a wave of CL. It reached maximum intensity around 40 min after the reaction mixture heating and cooling it down. CL intensity elevation was accompanied by certain decoloration of the solution. Appearance of light absorbing substances and development of CL depended critically upon the temperature of preincubation (greater than or equal to 93 degrees Celsius), initial pH (greater than or equal to 11,2), sample volume (greater than or equal to 0.5 ml) and reagents concentrations. Dependence of total counts accumulation on a system volume over the critical volume was non-monotonous. After reaching maximum values CL began to decline, though only small part of glucose and glycin had been consumed. Brief heating of such solutions to the critical temperature resulted in emergence of a new CL wave. This procedure could be repeated in one and the same reaction system for several times. Whole CL kinetic curve best fitted to lognormal distribution. Macrokinetic properties of the process are characteristic of chain reactions with delayed branching. Results imply also, that self-organization occurs in this system, and that the course of the process strongly depends upon boundary conditions and periodic interference in its course.

Transmittance spectra and spectra of optical loses due to absorption and scattering of different biofluids were registered by spectrophotometer DU-64 Beckman in the range of wavelength from 200 to 900 nm. The alteration of spectra of blood serum and whole blood were observed after irradiation of the samples by laser light (633 or 850 nm). The preliminary results indicating that the laser effects depend on the initial biophysical and biochemical state of blood are discussed.

Method of erythrocyte sedimentation rate (ESR) measurement is non-specific one. The ESR are tightly correlated to increase or decrease of aggregation coefficient (N). The variations of N could happen due to two main reasons: either changes in concentration of plasma proteins (first of all of fibrinogen) or changes of erythrocyte membrane characteristics (surface charge, transmembrane potential). The cross-method of ESR analysis has been proposed, using blood samples from patient and healthy donor of the same ABO blood groups and Rh-factors. The hematocrit (H_o)-ESR dependencies were measured in four variants: (1) patient's erythrocytes in patient's plasma; (2) patient's erythrocytes in donor's plasma; (3) donor's erythrocytes in donor's plasma; (4) donor's erythrocytes in patient's plasma. On presenting the ESR data for more than 100 patients with different bone marrow disorders after chemotherapy in the coordinates H_o-ESR three conventional zones could be marked out: high-ESR zone, medium zone and zone of low level of H_o. Proposed cross-method allows to estimate which of the two aforementioned reasons results in ESR variation. Some patients revealed not only changed fibrinogen level but additional changes in membrane affinity to fibrinogen. The modificated ESR cross-method opens us some new capacities in medical diagnostics.

Blood Microcirculation includes many of different components, which are joined by unique multiple system. Capillaries are one of the main link in this morpho-functional chain. Changes in any components of blood microcirculation are revealed by many of pathological processes in different organs and systems of the whole organism. We investigated 250 patients from 30 to 77 ages. Men included 149, women -- 101. The main diagnosis of all patients was the ischaemic pancreatitis. For verification of this diagnosis we used the whole spectrum of clinical, laboratorial and instrumental methods. These were the following: the definition of amylase of blood and urine, sonography and computer's tomography of pancreas, angiography of vessels of pancreas and Doppler's sonography of abdominal aorta and her branches: arteria mesenterica superior (AMS), truncus coeliacus (TC), arteria hepatica communis (AHC) and arteria lienalis (AL). We investigated the blood microcirculation of the mucous of the inferior lip, using Laser Dopplerography. The equipment for this research was LACC-01 with modified computer's program. The normal levels of blood microcirculation were from 120 to 180 Units. But patients with ischaemic pancreatitis had more lower level than in normal situation. This method are suggested as express diagnostic in the cases of abdominal ischaemic pathology. It can used as singel method or in combined with ultrasound Dopplerography.

We investigated the optical properties (mu) _a, (mu) _s, and g of human blood under flow conditions using integrating sphere measurements and inverse Monte-Carlo-simulations. The experiments were conducted at 633 nm with regard to the influence of the most important physiological and biochemical blood parameters. In addition, a spectrum of all three parameters was measured in the wavelength range 400 to 2500 nm for oxygenated and deoxygenated blood.

The dielectric and magnetic influence on human cells have been widely studied previously by the authors. Recently, the effects of energy in the visible electromagnetic spectrum have been investigated. In this subsequent study, the photonic effects on the in vitro migration of the polymorphonuclear and mononuclear leukocytes are compared with the corresponding electromagnetic field effects. Dielectric spectra of the polymorph in the 300 KHz to 400 KHz and 700 KHz to 800 KHz range have been measured. At frequencies of 350 KHz and 720 KHz an increase in the migration of the polymorphonuclear leukocyte have been observed. This stimulation was attributed to the charges on the nuclear surface. Recent preliminary data have shown a similar increased migration in the 20 MHz range. Photonic studies have indicated an enhanced migration for the polymorphonuclear leukocytes at a wavelength of 660 nm (red) and an inhibited migration at 565 nm (green). The photonic effects were postulated to be the results of a biochemical interaction rather than a membranous surface charge displacement secondary to an electric field. The migration of the white blood cells were measurement via the Boyden chamber technique and expressed in terms of a cytokinetic index which expresses the cellular movement independent of its environmental concentration gradient.