This work is aimed at creating a modified invasive technique for assessing the liver’s functional reserves. A study of the degree of hepatodepression is carried out by measuring the plasma elimination of indocyanine green using the method of optical densitometry. This paper presents test results for an aqueous solution and an albumin solution, as well as the results of measurements of plasma elimination of indocyanine green for patients with liver disease. Perfecting the proposed method will make an important scientific contribution to modern diagnostic medicine. Diagnosing the stages in the progression of the disease and its developing complications can make it possible to rapidly correct the patient’s treatment algorithm, achieving positive outcomes in medical practice.

The work is dedicated to determination of physical parameters of micro- and nanoparticles by static light scattering method. We present static light scattering device and theory to determine sizes of particles in suspensions. We analyze calculated distributions of scattering intensity for particles of different sizes and compare it with experimental data, received for spherical particles of different sizes. We also suggest theory to calculate form factor of scattering intensity for micro- and nanoparticles of different shapes. We also demonstrated that Rayleigh scattering theory is better to be applied for small particles investigation.

OBJECTIVE To justify the optimal method for determining indocyanine green plasma disappearance rate (PDR_ICG). MATERIAL AND METHODS We analyzed PDR_ICG in intensive care units. Indocyanine green was administered intravenously at a dose of 0.25 mg/kg. PDR_ICG was analyzed simultaneously by using of three methods: 1) PDD (PiCCO2 LiMON device), 2) SBS with analysis of plasma samples on precise spectrophotometer, 3) SBS with analysis of plasma samples on simple experimental photometer. RESULTS PDD method was used for 346 PDR_ICG tests in 256 patients. Of these, 14.3% of measurements were erroneous. Paired tests using PDD and SBS methods were performed in 299 cases. SBS method resulted erroneous data in 0.6% of cases. Certain correlation (r=0.79, p<0.001) was found between the reference method (SBS with spectrophotometry) and the PDD method. Bland—Altman plot for these two methods showed that proportional bias of mean difference was caused by extremely high PDR_ICG of the PDD method (for example, more than 30%/min). Comparison of two SBS variants (spectrophotometer and experimental photometer) revealed good correlation (r=0.91, p<0.001). CONCLUSION SBS method for measuring PDR_ICG ensures accurate results under mechanical interferences in patients with impaired capillary blood flow. This eliminates the need for redo measurement. Duplication of the PDD and SBS methods is recommended when repeating the test is not possible (organ donors).

A pressing health problem, both in clinical and socio-economic terms, is the increase in the number of patients with liver damage caused by viral diseases (hepatitis), cancer, toxicological damage, or metabolic disorders. Liver function assessment is a complex task, for which various existing diagnostic methods are used. Unfortunately, they all have several limitations which frequently make prompt and accurate diagnosis impossible. The high level of disability and mortality caused by liver diseases makes the development of new liver diagnostic methods very urgent. In this paper, we describe a new joint methodology for studying liver function based on optical densitometry and dynamic light scattering. This will help to diagnose and predict the dynamics of liver function during treatment with greater efficiency, due to including in consideration the individual characteristics of the cardiovascular system and tissue metabolism. In this paper, we present a laboratory model of a combined sensor for optical densitometry and dynamic light scattering. We also developed special software for controlling the sensor and processing the recorded data. Modeling experiments and physical medical studies were carried out to adjust and calibrate the sensor and software. We also assessed the sensor resolution when registering the concentration of dye in the human body and the minimum measured flow rate.