Biomedical subjects
Publications and source records attributed to Y Romanov.
Structural peculiarities of the epithelium and connective tissue stroma of vascular plexuses in amphibian brain are examined. Quantitative and qualitative characteristics of the pool of cell regulators of regional hemodynamics during normothermy and deep winter torpidity are determined.
It is well known that endothelial cells (EC) are highly sensitive to mechanical influences such as hemodynamic conditions or pulsatile stretch. However, it is still unknown, how endothelium responds to the changed gravity. The results of some studies suggest that cellular elements of vascular wall and, particularly, endothelium, may directly participate in development of physiological responces to microgravity. On our suggestion, this is extremely attractive since vascular endothelium is one of the main regulators of vascular tone (via its interaction with vascular smooth muscle cells) and, consequently, can play not last role in maintaining of normal cardiovascular system operation in microgravity. On the other hand, the endothelium itself may be regarded as a widely dispersed organ of approximately 1.5 kg in weight (in the adult human organism). Finally, endothelium is not just a passive barrier between vascular wall and circulating blood but synthesizes, metabolizes, and releases a substances which act on adjacent cell systems or distant cell structures. The main aims of this study were: 1) the development of experimental model, allowing to study functional parameters of human endothelial cells in hypogravity conditions in vitro; 2) the verification of endothelial sensitivity to gravitational micro-environment.
The microarchitecture and cell composition of intima were studied at the macroscopically unaffected branch regions of human thoracic aorta using en face preparations, scanning and transmission electron microscopy, and immunohistochemistry. The endothelial lining showed a heterogeneous pattern and altered morphology including the areas of deendothelialization covered with platelets and dilated intercellular clefts. Leukocyte adhesion, accumulation of subendothelial macrophages and lymphocytes were characteristic of proximal and lateral zones, while the flow divider showed no significant accumulation of blood cells. Smooth muscle cells (SMCs) on the flow divider were elongated, in a contractile state, contacted side-by-side and did not contain lipid inclusions. In the lateral and proximal zones, intima appeared to be a network of stellate SMCs which were in contact through their processes. Most of the SMCs were in a synthetic state and many of them contained small lipid droplets. The number of procollagen I positive cells and the volume of extracellular components were most significant at the lateral zones rather than at the flow divider. We did not observe any difference in the rate of proliferation. Our results suggest that the intimal layer at the lateral and proximal zones has some distinct structural peculiarities, which provoke the development of initial atherosclerotic lesions at these sites. Such an intimal structure is probably caused by different flow patterns at these zone. However, only the totality of different morphological features exhibited in the area of altered vascular wall shear stress may be considered as a prerequisite for atherosclerotic lesions.
Times of heightened susceptibility are expressed by nonrandom patterns in the incidence of various diseases, not only along the scale of a day but also of a week and a year. Whereas these rhythms can be synchronized by the environment, their endogenicity is revealed by their persistence in the absence of time cues with a period slightly but statistically significantly different from the environmental match. In the case of some circadians, the gene involved has been identified and heritabiliy in humans determined by studies on twins. Vital signs are now amenable to automatic monitoring around the clock. When analyzed by chronobiologic software, the data provide information regarding the given individual's time structure (chronome). Such physiologic monitoring serves the multiple purposes of deriving time-specified reference norms on the basis of which rhythm alteration can detect an elevated risk early, thus prompting timely preventive action and timed treatment whenever warranted. For long journeys in space, the design of a multi-disease prophylactic pill poses a chronopharmacologic challenge. Drugs such as aspirin and carnitine, used for the prevention of strokes, myocardial infarctions and depression, all show striking chronome-dependent effects which can determine not only the presence or the absence of a desired effect, but even yield effects in opposite directions.
AIMS: Velocity changes in the solar wind, recorded by satellite (IMP8 and Wind) are characterized by a solar cycle dependent approximately 1.3-year component. The presence of any approximately 1.3-year component in human blood pressure (BP) and heart rate (HR) and in mortality from myocardial infarction (MI) is tested and its relative prominence compared to the 1.0-year variation. MATERIALS AND METHODS: Around the clock manual or automatic BP and HR measurements from four subjects recorded over 5 to 35 years and a 29-year record of mortality from MI in Minnesota were analyzed by linear-nonlinear rhythmometry. Point and 95% confidence interval (CI) estimates were obtained for the approximately 1.3-year period and amplitude. The latter is compared with the 1.0-year amplitude for BP and HR records concurrent to the solar data provided by one of us (JDR). RESULTS: An approximately 1.3-year component is resolved nonlinearly for MI, with a period of 1.23 (95% CI: 1.21; 1.26) year. This component was invariably validated with statistical significance for BP and HR by linear rhythmometry. Nonlinearly, the 95% CI for the 1.3-year amplitude did not overlap zero in 11 of the 12 BP and HR series. Given the usually strong synchronizing role of light and temperature, it is surprising that 5 of the 12 cardiovascular series had a numerically larger amplitude of the 1.3-year versus the precise 1.0-year component. The beating of the approximately 1.3-year and 1.0-year components was shown by gliding spectra on actual and simulated data. DISCUSSION AND CONCLUSION: The shortest 5-year record (1998-2003) revealed an approximately 1.3-year component closer to the solar wind speed period characterizing the entire available record (1994-2003) than that for the concurrent 5-year span. Physiological variables may resonate with non-photic environmental cycles that may have entered the genetic code during evolution.