Publications by authors named "L R Gavrilov"

129 Publications

What Can We Learn about Aging and COVID-19 by Studying Mortality?

Biochemistry (Mosc) 2020 Dec;85(12):1499-1504

Academic Research Centers, NORC at the University of Chicago, Chicago, IL 60637, USA.

Promising ideas and directions for further research into biology of aging are discussed using analysis of the age-related kinetics of organisms' mortality. It is shown that the traditional evolutionary theory explaining aging by decreasing force of natural selection with age is not consistent with the data on age-related mortality kinetics. The hypothesis of multistage destruction of organisms with age, including the rate-limiting stage of transition to a state of non-specific vulnerability ("non-survivor"), is discussed. It is found that the effect of the COVID-19 coronavirus infection on mortality is not additive (as it was the case with the Spanish flu epidemic in 1918), but multiplicative (proportional) for ages over 65 years.
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http://dx.doi.org/10.1134/S0006297920120032DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7768994PMC
December 2020

Patterns of mortality during pandemic: An example of Spanish flu pandemic of 1918.

Popul Econ 2020 30;4(2):56-64. Epub 2020 Apr 30.

University of Chicago, 60637, USA; Federal Research Institute for Health Organization and Informatics of Ministry of Health of the Russian Federation, Moscow, 127254, Russia; Institute of Socio-Political Research at the Federal Center of Theoretical and Applied Sociology of the Russian Academy of Science, Moscow, 119333, Russia.

Now the attention of the whole world is focused on the developing pandemic of the coronavirus infection COVID-19. This article discusses mortality patterns of the deadliest epidemic in the last 120 years - the Spanish flu pandemic of 1918. Statistical sources from Italy and the USA, published shortly after the pandemic, were analyzed. The analysis was carried out for mortality from all causes, since in this case inaccuracies associated with establishing the causes of death are minimized. Despite the fact that the first cases of the Spanish flu appeared in the United States as early as March 1918, this first wave of epidemic practically did not affect the total mortality rate. The main peak of mortality in 1918 occurred in October 1918 both in the USA and Italy, with a gradual decrease in mortality over several months. Analysis of age-specific mortality demonstrates a significant increase in mortality at middle ages (20-50 years) in 1918 compared with 1917. Analysis of mortality trends using the method of latent variables shows a significant increase in the background mortality factor in 1918, which turned out to be higher for Italy than the mortality losses during the Second World War. The Spanish flu pandemic differs from the current coronavirus pandemic, because of significant increase in mortality of middle-aged people, while the COVID-19 pandemic causes a more marked increase in mortality among the elderly. With this, the COVID-19 pandemic is more like the recent flu epidemics than the earlier Spanish flu pandemic.
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http://dx.doi.org/10.3897/popecon.4.e53492DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7351247PMC
April 2020

Simulation of nonlinear trans-skull focusing and formation of shocks in brain using a fully populated ultrasound array with aberration correction.

J Acoust Soc Am 2019 09;146(3):1786

Department of Acoustics, Physics Faculty, Moscow State University, Leninskie Gory, Moscow 119991, Russia.

Multi-element high-intensity focused ultrasound phased arrays in the shape of hemispheres are currently used in clinics for thermal lesioning in deep brain structures. Certain side effects of overheating non-targeted tissues and skull bones have been revealed. Here, an approach is developed to mitigate these effects. A specific design of a fully populated 256-element 1-MHz array shaped as a spherical segment (F-number, F = 1) and filled by randomly distributed equal-area polygonal elements is proposed. Capability of the array to generate high-amplitude shock fronts at the focus is tested in simulations by combining three numerical algorithms for linear and nonlinear field modeling and aberration correction. The algorithms are based on the combination of the Rayleigh integral, a linear pseudo-spectral time domain Kelvin-Voigt model, and nonlinear Westervelt model to account for the effects of inhomogeneities, aberrations, reflections, absorption, nonlinearity, and shear waves in the skull. It is shown that the proposed array can generate nonlinear waveforms with shock amplitudes >60 MPa at the focus deep inside the brain without exceeding the existing technical limitation on the intensity of 40 W/cm at the array elements. Such shock amplitudes are sufficient for mechanical ablation of brain tissues using the boiling histotripsy approach and implementation of other shock-based therapies.
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http://dx.doi.org/10.1121/1.5126685DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7064313PMC
September 2019

Measuring Aging and Identifying Aging Phenotypes in Cancer Survivors.

J Natl Cancer Inst 2019 12;111(12):1245-1254

Observational data have shown that some cancer survivors develop chronic conditions like frailty, sarcopenia, cardiac dysfunction, and mild cognitive impairment earlier and/or at a greater burden than similarly aged individuals never diagnosed with cancer or exposed to systemic or targeted cancer therapies. In aggregate, cancer- and treatment-related physical, cognitive, and psychosocial late- and long-term morbidities experienced by cancer survivors are hypothesized to represent accelerated or accentuated aging trajectories. However, conceptual, measurement, and methodological challenges have constrained efforts to identify, predict, and mitigate aging-related consequences of cancer and cancer treatment. In July 2018, the National Cancer Institute convened basic, clinical, and translational science experts for a think tank titled "Measuring Aging and Identifying Aging Phenotypes in Cancer Survivors." Through the resulting deliberations, several research and resource needs were identified, including longitudinal studies to examine aging trajectories that include detailed data from before, during, and after cancer treatment; mechanistic studies to elucidate the pathways that lead to the emergence of aging phenotypes in cancer survivors; long-term clinical surveillance to monitor survivors for late-emerging effects; and tools to integrate multiple data sources to inform understanding of how cancer and its therapies contribute to the aging process. Addressing these needs will help expand the evidence base and inform strategies to optimize healthy aging of cancer survivors.
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http://dx.doi.org/10.1093/jnci/djz136DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7962788PMC
December 2019

New Trend in Old-Age Mortality: Gompertzialization of Mortality Trajectory.

Gerontology 2019 20;65(5):451-457. Epub 2019 May 20.

Academic Research Centers, NORC at the University of Chicago, Chicago, Illinois, USA.

There is great interest among gerontologists, demographers, and actuaries in the question concerning the limits to human longevity. Attempts at getting answers to this important question have stimulated many studies on late-life mortality trajectories, often with opposing conclusions. One group of researchers believes that mortality stops growing with age at extreme old ages, and that hence there is no fixed limit to the human life span. Other studies found that mortality continues to grow with age up to extreme old ages. Our study suggests a possible solution to this controversy. We found that mortality deceleration is best observed when older, less accurate life span data are analyzed, while in the case of more recent and reliable data there is a persistent mortality growth with age. We compared the performance (goodness of fit) of two competing mortality models - the Gompertz model and the Kannisto ("mortality deceleration") model - at ages of 80-105 years using data for 1880-1899 single-year birth cohorts of US men and women. The mortality modeling approach suggests a transition from mortality deceleration to the Gompertzian mortality pattern over time for both men and women. These results are consistent with the hypothesis about disappearing mortality deceleration over time due to improvement in the accuracy of age reporting. In the case of more recent data, mortality continues to grow with age even at very old ages. This observation may lead to more conservative estimates of future human longevity records.
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http://dx.doi.org/10.1159/000500141DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6703938PMC
February 2020