This paper presents the experimental setup and first results of a near infrared CCD based Photoplethysmographic Imager (PPGI) which has been shown to be suitable for contactless assessing various disorders of the peripheral venous system by standard test methods derived from the classical photoplethysmographic practice. The PPGI is a computer-based CCD near-infrared imaging system to visualize the skin vessels and analyze the local changes in dermal blood volume. Our current results show that this system performs as well as the available commercial PPG system by adding information of spatial distribution which allows the investigation of locations and causes of vascular disorders.

Laser Doppler perfusion imaging has been used to assess the myocardium perfusion on the arrested heart during bypass surgery. Twenty-two patients undergoing coronary artery bypass grafting, including usage of the left internal thoracic artery, were included in the study. The anticipated perfusion increase following declamping of the internal thoracic artery was investigated by mapping areas at the size of 10 cm X 11 cm, (n equals 11) and 7 cm X 5 cm (n equals 11). The larger images allowed quantification of blood flow in different regions of the myocardium. The size of the affected area was 32.2 +/- 12.9 cm² with a total increase of 3.17 +/- 0.75 a.u. (range 0 - 10 a.u.). Corresponding values for areas surrounding the vessels and areas defined as the larger vessels in the myocardium were 29.0 +/- 10.9 cm² (2.85 +/- 0.57 a.u.) and 3.5 +/- 2.8 cm² (6.78 +/- 0.18 a.u.). All subjects but two showed a substantial blood flow increase (> 2 a.u.) after release of the clamp. Six subjects had a total increase of at least 4 a.u. Correlation analysis between areas including various number of sites showed an r equals 0.91 (p < 0,0001) or better. In conclusion, laser Doppler perfusion imaging can easily be used intraoperatively in conjunction with bypass surgery. It enables immediate assessment of both the increase and spatial distribution of myocardial perfusion following declamping of an arterial graft.

To assess the microcirculation parameters of diabetes sufferers we used the method of computerized capillaroscopy that allows one to visualize non-invasively and measure at a high accuracy the size of the perivascular zone, the blood flow velocity in the capillaries and the presence and duration of stasis. The sludge phenomenon and lipid inclusions also we studied non-invasively.

The aggregation and disaggregation behavior of erythrocytes reflects pathological states of the human body. The investigation of the aggregation and disaggregation process of human blood samples by laser spectroscopic measurements is described int he present paper. The whole blood samples were analyzed using a rotating coaxial cylinder system in combination with a special method for data processing. The erythrocyte aggregates were destroyed completely without injuring the cell membranes by shear forces arising during the cylinder rotation. The time behavior of the remission signal during the aggregation process was investigated. The disaggregation process was characterized by the dependence of the remission signal intensity on different applied shear rates.

An automatic device for high-temporal resolution of the process of red blood sedimentation was designed. The position of the boundary between red blood and plasma may be registered each 30 sec in several pipettes simultaneously with +/- 10 mkm precision. Fractional rates of the boundary movement are deduced with high accuracy. Data are processed by a PC and presented as velocity-time curves (ESR-grams) and the curves describing time evolution of the boundary position. Several unexpected phenomena in the process of red blood sedimentation have been revealed. Upward fast movements of the boundary up to 1 mm were noted. In patients' blood sets of 5 - 10 milliHz oscillations of sedimentation rate were usually developing at early stages of blood sedimentation. In non-diluted healthy donors' blood high amplitude periodic oscillations were either absent, or were emerging only after blood resided in pipettes for several hours. When blood was diluted to a certain degree with physiological saline or with own plasma long-term low frequency (1 - 3 milliHz) rate oscillations regularly appeared. Non-trivial dependence of patterns of ESR-grams on diluting of blood with own plasma or saline was observed. Thus, non-linear dynamic behavior of living blood has been revealed due to application of the principles of the system of technical vision for the detailed analysis of red blood sedimentation kinetics.

The scattering of He-Ne laser light incident on a flowing column of whole human blood has been measured and analyzed. An automated scatterometer whose sample chamber simulates a small caliber blood vessel was used to perform the measurements and is described. Angular scattered light distributions due to flowing blood columns for two independently varied parameters, blood oxygenation and hemoglobin concentration, are presented. It is found that the dependence of the scattering distribution on blood oxygenation is minimal while the dependence on hemoglobin concentration is strong. A nominally transparent sample of human plasma has also been investigated to quantify its scattering characteristics. The whole blood scattering results are compared to theoretical predictions obtained using a Monte Carlo simulation employing the Mie single particle phase function and macroscopic transport coefficients obtained from published literature. The best correlation was found when the largest published scattering coefficient was employed in the simulation. However, a strong correlation between the measured and predicted scattering distributions was only obtained when unphysically high values of the scattering coefficient were used in the simulation.

The influence of emitting-receiving fiber distance on the perfusion signal in laser Doppler flowmetry (LDF) for a range of optical properties has been studied. A custom made LDF probe with eight 230 micrometers fibers arranged in a row was used.

The application of optical polarimetry, using the anterior chamber of the eye as the sensing site, is being investigated as a potential method to develop a noninvasive physiological glucose monitor. First, we present results characterizing the optical rotatory dispersion of the main optically active analytes found within the aqueous humor of the eye including, glucose, albumin, and ascorbic acid. This information is used in conjunction with multiple linear regression to demonstrate how multispectral polarimetry can be used to minimize glucose prediction error in samples containing varying physiological concentrations of glucose and albumin. For this multispectral study, a novel dual wavelength (532 nm and 635 nm) polarimeter was designed and constructed. This sensor is novel in that it provides simultaneous measurements using a 532 nm laser in an open- loop configuration and a 635 nm laser in a closed-loop configuration. In addition, we present in vivo results using New Zealand White rabbits that indicate the time delay between blood and aqueous human glucose levels is below ten minutes. Lastly, we provide preliminary in vivo polarimetric results and discuss the main issues currently hindering the measurement of glucose.

A painless monitoring procedure for diabetics has proven to be an elusive goal. While completely noninvasive measurements are the desired technique, minimally invasive procedures using implanted fluorescence sensor chemistry offer significant advantages in specificity over current noninvasive approaches. The goal was to evaluate the potential for transdermal glucose sensing using intensity measurements from implanted microspheres. A fiber-optic probe and spectrometer were custom-built for collection of in vivo data. Comparisons with commercial fluorometers show the constructed device is adequate for this project.

The objective of this study was to determine the effect of pH on near-infrared (NIR) (2.0 - 2.5 micrometers ) spectra of glucose in phosphate buffered saline solution within a tight range of control similar to what is found in many mammalian organisms and cell cultures. It is known that the NIR water spectrum in the wavelength range (2 - 2.5 micrometers ) may be altered by pH, and it has been shown that glucose absorbance spectra do not change with pH when an equal reference pH is available. However, because the glucose absorbance spectra rides on the water spectra, changes in the spectral characteristics did occur. These effects need to be considered, in particular for single beam glucose spectra.

The work is devoted to the investigation of the mechanisms forming a structure of a light field under interaction of electromagnetic radiation with the suspension of the biological particles. The basic asymptotic formulas are reduced. The effects of influence of the inner structure of the particles on the light-scattering pattern in a comparison with those of homogeneous particles are shown. The sphere with radially inhomogeneous profile of refractive index, coated sphere and coated sphere with refractive index with inhomogeneous profile of the outer layer were used as the models for description of light-scattering of the spherical biological particles with different inner structure.

In this work we compare experimental results with results of numerical simulations. For our measurements, we used both spatial-resolved and frequency-domain techniques. To describe propagation of photons we solved the rigorous radiative transfer equation (RTE). We found that the Monte- Carlo method (MC) is too time-consuming for large source- detector separations. We achieved flexibility in preparation of experimental medium with tissue-simulating sample containing of several homogeneous layers. Our objective is the investigation of accuracy in determining unknown structures and optical coefficients from measured data, based on the realistic model of the tissue described in the RTE. We have shown that, by comparing the use of the RTE to the diffusion approximation or MC, we achieve better accuracy or universality in source-detector distances.

Erythrocytes can be agglutinated by the antigen-antibody reaction, with variable strength depending on the intercellular adhesive energy of antibodies (affinity) and on the antigenic density on the cell surface. A new technology based on light backscattered by a thick layer of a concentrated suspension of erythrocytes under shear stresses to estimate the intercellular adhesive energy has been developed. This adhesive energy is estimated by recording kinetically the laser back scattered intensity during the time the agglutinates become dissociated by shear in a Couette system. The Regulest Erithroaggregameter measures the changes in back scattered light when the suspension of agglutinated erythrocytes is brought to a high shear rate of 600 s^-1. The increase in optical signal reflects the gradual dissociation of agglutinates. Three dynamic parameters are derived from the obtained curves by a simple numerical process. A parameter of energy is defined by the area subtended between the curve from the agglutinated sample and that one from the non agglutinated sample. The method provides information on the agglutination strength and on the antibody affinity. This technique was successfully applied to the quality control of monoclonal antibodies and to help in the diagnosis of hemolytic anemias caused by cold agglutinins.

A new method to find directly complex viscoelastic parameters (CVP) of human red blood cells is presented in this paper. Experimental determinations were carried out in an Erythrodeformeter operating in oscillating mode (0.5 to 3.5 Hz). The Erythrodeformeter performs direct determination of CVP of erythrocytes undergoing sinusoidal shear stresses by laser diffractometry.

Aggregation and disaggregation processes of lipid vesicles in water suspension were studied by computer simulation and laser backscattering techniques. Diffusion-limited aggregation algorithm of simulation model was enhanced to reversible cluster growth. It was estimated that morphological structure of clusters is controlled by the ratio of secondary minimum depth of vesicles interaction potential and their kinetics energy. Shear flow in Couette chamber made it possible to induce aggregation/disaggregation of vesicles under the different values of their kinetic energy due to shear flow ratio shift. Characteristic times of stasis and shear flow induced aggregation kinetics were determined by laser backscattering. Computer simulation is in good agreement with experimental data.

In the present study the characteristics of lymph flow in microvessels are investigated in vivo by the speckle- interferometrical and biomicroscopic methods. Two parameters of the lymph flow velocity are determined. The first frequency-weighted spectral moment of Doppler signal (M₁) was calculated. This parameter is proportional to lymph flow velocity. In the same regions of lymphatics the velocity of translational motion of the signal lymphocytes in the flow is assessed. The value of velocity and the parameter M₁ essentially varied. The temporary dynamics of M₁ indicated that the lymph flow had the alternating- translational character. Simultaneously the diameter of lymph microvessel, the amplitude and the rate of phasic contraction and the rate of valve functioning are registered. N^G-nitro-L-arginine (L-NNA, 10^-4 M), an inhibitor of nitric oxide synthase, is topically applied during 15 min. The application of L-NNA provoked the modulation of alternating-translational motion of lymph flow, the changes of diameters and rate of valve function and the stimulating of phasic contractions and the correlation between parameters of lymph microcirculation.

Magnetic sedimentation processes near ferromagnetic wire were applied for the cellular and the biotechnological monitoring. Numerous biological applications of magnetic sedimentation, or high gradient magnetic separation (HGMS), achieved mainly for human blood cells, have shown that it is possible to distinguish between the diamagnetic Fe-zero-spin oxidized states and the paramagnetic Fe-high-spin reduced ones in red blood cells. The precision methods of the measurements of capture travelling (magnetic diffusion) time or accumulation (magnetic sedimentation) radius in HGMS have shown that it is really to determine the weak dia- or paramagnetic shifts of magnetic susceptibility up to 0.7 (DOT) 10^-10 (SI). The capture and sedimentation of particles with 5 - 40 micrometers sizes on single magnetized wires were investigated using microscopic video-recording type. Magnetic susceptibility bars for cells in normal and disturbed states demonstrated the high reproducibility and narrow distribution patterns.

At present in hematology there are no quantitative estimates of such important for the cell classification parameters: cell form and nuclear form. Due to the absence of the correlation between morphological parameters and parameters measured by hemoanalyzers, both flow cytometers and computer recognition systems, do not provide the completeness of the clinical blood analysis. Analysis of the spatial-frequency spectra of blood samples (smears and liquid probes) permit the estimate the forms quantitatively. On the results of theoretical and experimental researches carried out an algorithm of the form quantitative estimation by means of SFS parameters has been created. The criteria of the quality of these estimates have been proposed. A test bench based on the coherent optical and digital processors. The received results could be applied for the automated classification of ether normal or pathological blood cells in the standard blood smears.

The investigation upon the necessity and the reliability required of the determination of the poikilocytosis in hematology has shown that existing techniques suffer from grave shortcomings. To determine a deviation of the erythrocytes' form from the normal (rounded) one in blood smears it is expedient to use an integrative estimate. The algorithm which is based on the correlation between erythrocyte morphological parameters with properties of the spatial-frequency spectrum of blood smear is suggested. During analytical and experimental research an integrative form parameter (IFP) which characterizes the increase of the relative concentration of cells with the changed form over 5% and the predominating type of poikilocytes was suggested. An algorithm of statistically reliable estimation of the IFP on the standard stained blood smears has been developed. To provide the quantitative characterization of the morphological features of cells a form vector has been proposed, and its validity for poikilocytes differentiation was shown.

The paper investigated in vivo the influence of low- intensity laser radiation (He-Ne laser with wavelength 0.63 nm) on the relative value of perfusion (the product of the number of particles moving in the volume being investigated into the mean velocity of their movement) of human blood erythrocytes and the mean velocity of their movement. It is known that characteristic of cardiovascular diseases are microcirculation disturbances and disorder in rheological properties of blood. Therefore these investigations were carried out on cardiac ischemia patients.

An experimental facility has been developed that allows for the determination of the scattering cross section and the scattering phase function of thin layers of undiluted blood. The layer is formed between to flat glass plates. By rotating one of the plates, a simple shear can be imposed onto the blood. Experiments have been performed with 633 nm light on layers with a thickness between 20 and 60 micrometer. It was shown that for shear rates in the range 150 - 500 s^-1, the scattering coefficient has a constant value of 115 mm^-1. Also, the scattering anisotropy for single scattering g ranges from 0.95 at lower shear rates, to 0.975 at higher shear rates. The value of g increases with the shear, both in a direction parallel to and perpendicular to the shear direction.