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January 16, 2019
Drones may one day make your life easier by delivering pizza, but today—in Rwanda—they are already playing a vital role in emergency medical services.
Epigenetics refers to information transmitted during cell division other than the DNA sequence per se, and it is the language that distinguishes stem cells from somatic cells, one organ from another, and even identical twins from each other. Examples include (1) DNA methylation, a covalent modification of the nucleotide cytosine, that is copied during cell division at CpG dinucleotides by the maintenance enzyme DNA methyltransferase I; (2) posttranslational modifications of nucleosome proteins about which the DNA double helix is wrapped; and (3) the density of nucleosomes and higher-order packaging of chromatin within the nucleus, including its relationship to the nuclear lamina.
In contrast to the DNA sequence, the epigenome is relatively susceptible to modification by the environment as well as stochastic perturbations over time, adding to phenotypic diversity in the population. A classic example is the environmentally modified phenotype of the Agouti gene, which regulates coat color and weight in mice and is manifest through epigenetic changes. A repetitive DNA variant within this gene can activate the gene in a nonregulated way, causing a yellow coat and obesity in the mice. This activation can be suppressed by DNA methylation, which can be modulated by supplying more or less dietary methionine, the essential amino acid that is the precursor of all DNA methylation in the cell.1 Similar epigenetically mediated changes can be evoked via chemical exposure and even maternal behavior.2 In humans, there has long been suspicion of the importance of nutrition in early life in modulating the epigenome. The classic epidemiological example of Överkalix, Norway, showed lower life expectancy for boys whose grandfathers had experienced famine prepubertally.3 During the Dutch Hunger Winter and Great Leap Forward, which involved starvation of huge numbers of people, children exposed in utero to the famine during their first trimester show DNA methylation changes in genes associated with birth weight and low-density lipoprotein cholesterol.4 A recent study of in utero nutritional deprivation in mice showed epigenetic changes continuing via the germline to the next generation but not beyond.5
SCIENTIFIC DISCOVERY AND THE FUTURE OF MEDICINE
The human body is soft, curvilinear, and continuously evolving; modern electronic devices are rigid, planar, and physically static. Recent research has yielded a complete set of advanced materials, manufacturing approaches, and design layouts that eliminates this profound mismatch in properties. The resulting devices can intimately integrate onto or into the human body for diagnostic, therapeutic, or surgical function with important unique capabilities in biomedical research and clinical medicine. These emerging technologies have strong potential to improve human health and to enhance the understanding of living systems. They fall into 3 categories—soft, injectable, and bioreabsorbable electronics—each demonstrated in extensive animal studies and several in initial human trials. The Figure presents images of bioelectronic devices.
Figure. Images of Biocompatible Electronic Devices A, Inflated balloon catheter equipped with arrays of sensors for pressure, flow, and contact along with actuators for ablation therapy and light-emitting diodes for optical characterization. B, Three-dimensional membrane wrapped around the entire surface of the heart for cardiac electrotherapy. C, Actively multiplexed sheet of electronics laminated onto the surface of the brain for high-resolution electrocorticography. D, Wireless electronics mounted on the skin for continuous, multimodal monitoring of physiological status. E, Injectable optoelectronic system threaded through the eye of a sewing needle and wrapped around its shaft to highlight the small dimensions and flexible mechanics. F, Bioresorbable electronic circuit, partially dissolving in a drop of water. All of the constituent materials dissolve at controlled rates into harmless end products when exposed to biofluids.
A long-touted health-care revolution may at last be about to arrive
Oct 11th 2014 | ROME | From the print edition
THE idea of telemedicine—health care provided using telecommunications equipment—has a lengthy history. Radio News, an American magazine, devoted its cover to a patient at home consulting a doctor in his surgery via a television link as long ago as 1924. When NASA began monitoring astronauts in space in the 1960s, fantasy became reality. It has been touted as health care’s future ever since.
But even smartphones and tablets have failed to usher in the telemedicine revolution: most health care still happens face to face. Now, enthusiasts think the wait is nearly over. Governments have been slow to embrace an approach that could improve coverage and outcomes, as well as saving money. But they are under increasing pressure from ageing populations and a surge in chronic diseases, just as public budgets are being squeezed.