Natural and medical sciences

The Kaliningrad region has a sub-replacement fertility rate (with a total fertility rate of about 1.8) and a slightly negative rate of natural increase. With a net migration of up to 10,000 people per year (Russian regions account for 37 % of this figure), the population of the region is increasing and the workforce number is stable. Population change and age-sex structure forecasts strongly rely on the estimates of prospective net migration and a rate of natural increase. Accompanied by a decreasing age-specific mortality rate and growing life expectancy, the current age-specific fertility rate and net migration ensure a stable workforce number and a positive rate of natural increase, against the background of an increasing dependency ratio. The article considers possible measures to increase the birth rate, to reduce the morality rate, and to regulate migration processes.

In each historical period, regional models of agricultural practices are affected by a combination of natural, political, and economic factors. Such models incorporate indicators of changes in the cultivated land area, land structure, and the intensity of agricultural practices. At early stages, the evolution of a model is affected by natural conditions. Later, political (wars, revolutions, changes in national borders) and economic factors (economic crises, changes in the overall economic situation, and shifts in the structure of the economy) come to the fore. The time series of statistical data from 1890—1900 to 2015—2016 and the major events in the region’s history were juxtaposed and compared to identify the key stages in the formation of regional models of agricultural nature management in the Baltics and the Kaliningrad region. A comprehensive historical and geographical analysis helped to reconstruct balances for each landmark in the evolution of agricultural nature management in the Baltics and the Kaliningrad region. Several models existed in the region over the time – those of production curtailment in the war and post-war years and in the period following the collapse of the USSR and those of booming agriculture observed in 1913—1914, 1975—1980, and the past decade.

This article estimates the severity of ultrasonographic changes in the liver at different stages of fibrosis. Sixty-three patients underwent B-mode ultrasound scanning of the spleen and the liver and ARFI-elastography of the liver. Elastography measured the shear wave speed from the 9th, 8th, and 7th intercostal spaces in the anterior axillary line at a depth of 6.0 cm from the skin surface. It was established that patients with fibrosis stages F1 and F2 exhibited from one to four and those with fibrosis F3 and F4 from three to eleven ultrasonographic symptoms. In most cases, as fibrosis progressed, the number of ultrasonographic symptoms increased. Twelve patients with elastographyconfirmed fibrosis stage F2-F4 did not exhibit any apparent ultrasonographic symptoms. Within this group, 42 % of the patients with fibrosis stage F3 and F4 – or 8 % of all the patients – did not exhibit any ultrasonographic symptoms. One or two ultrasonographic symptoms appeared in 12 % of the patients with fibrosis stage F3-F4. It is concluded that even a single ultrasonographic symptom should be interpreted by the ultrasound specialist as a possible sign of fibrosis or cirrhosis.

This article estimates the accuracy of various formulas used to calculate the standard volume of the liver. The authors identify formulas most adequate for a comparison with volumetry results obtained using JT Childs’s easy-touse formula. The study employed the anthropometric data (age, sex, and weight) and the calculations of body height, body surface area (BSA), and liver sizes of 36 healthy volunteers. The volume of the liver was determined using different formulas that take into account either the body surface area or the product of the three dimensions of the liver (the oblique vertical size of the right lobe, the thickness of the right lobe, and the thickness of the left lobe). JT Childs’s formula was chosen as producing the most accurate results and as the most adequate for the use by a practicing ultrasound specialist. The deviation percentage of results obtained using the other formulas was calculated in relation to Childs’s formula. It is concluded that the most accurate formula for calculating the standard volume of the liver is that proposed by A Chouker. The formula can be used for reference purposes when conducting ultrasound volumetry of the liver according to JT Childs.

An excess of silicon compounds in the body leads to systemic deficiencies. Regardless of the way by which silicon compounds (silicon dioxide, asbestos, silicon, and silicon nanoparticles) enter the body, they always have a marked effect. It is established that these compounds play a part in the pathogenesis of renal diseases. The article provides a morphological description of the renal corpuscles of laboratory mice (n=10) during three months’ ad libitum administration of silicon in a concentration of 10 mg/l. Silicon compounds cause morphological changes in renal corpuscles – a reduction in the size of glomeruli and an increase in capsular space.

This paper addresses the historical development of the renal failure concept from antiquity to the present. The authors define the term ‘acute renal failure’ and ‘acute kidney injury’. The article presents a classification of these diseases. It is shown that the development of renal failure is associated with a significant increase in age-independent mortality. The main biomarker of a kidney injury, which may be elevated in patients with ischemic heart disease, is creatinine.