HIGH TESTOSTERONE
I’m grateful for the warnings threaded by means of Stephanie Pappas’s “The Fact about Testosterone” and wish to elaborate from private expertise. As a transgender man, I like the results of testosterone. However I found some unwelcome ones when my ranges climbed. My larger dosage was unintentional; I assumed my physician needed me to extend it every week till she mentioned, “Halt!”
It seems like one man’s accident is one other man’s goal, nonetheless, provided that cisgender males with testosterone within the regular vary of 300 to 1,000 nanograms per deciliter (ng/dl) can simply get prescriptions for the hormone. Above 1,000 ng/dl, I grew impatient, irritable and disturbingly apathetic. As soon as an keen listener at volunteer conferences, I felt like I used to be the one particular person within the room. All these different people with their human opinions! They exasperated me.
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STEVE HUITING NEVADA CITY, CALIF.
SLICE OF CONFUSION
In “Excellent Slice” [Advances], Max Springer describes a slicing drawback involving convex shapes as equal to “asking whether or not an avocado of a given measurement, irrespective of the precise form, can at all times be cut up into two halves with both sides revealing a minimum of some sizable slice,” within the case of three-dimensional objects.
Does “two halves” imply two true halves or two items? And does “some sizable slice” imply that the world of the reduce will not be zero—that the 2 “halves” usually are not related by only a thread?
DAWN JACOBS VIA E-MAIL
SPRINGER REPLIES: “Two halves” on this drawback means two disconnected items. Shifting your knife fully by means of a fruit at any angle will at all times provide you with two items however not essentially two halves. The outline of “some sizable slice” is capturing a deeper mathematical boundary on how massive the world of every of the 2 cross sections will probably be. As described in my article, the just lately proved results of the issue says we are able to at all times reduce an object into two items so that every has a cross part of a minimum of a given measurement. This will likely appear intuitive for fruits however will get extra complicated in larger dimensions.
ILLUMINATING MITOCHONDRIA
“Can Daylight Remedy Illness?,” by Rowan Jacobsen [June], leaves us with a way of thriller as to the mechanism of motion for the well being advantages of sunshine. But in the identical subject, a clue is obtainable by Martin Picard in “The Social Lives of Mitochondria.” The advantages of sunshine would possibly come up from its impact on the mitochondrial degree, as demonstrated in a July Scientific Studies paper by Glen Jeffery of College School London and his colleagues. Picard does suggest weight-reduction plan, socialization and train to optimize mitochondrial operate, together with in a short reference to his work with Nirosha Murugan of Wilfrid Laurier College in Ontario. However he doesn’t confer with the well being advantages of publicity to the outside.
HAROLD PUPKO TORONTO
Picard says that, thus far, the perfect speculation for a way mitochondrial DNA’s internal membrane folds, referred to as cristae, line up seems to contain “electromagnetic fields induced by the circulate {of electrical} cost throughout” these folds. He then goes on to explain how mitochondria talk with mitochondria in different cells chemically. Maybe mitochondria are the sector sensors and turbines, or presumably the “concentrators,” of biology.
DONALD WELLER HILLSBORO, ORE.
PICARD AND MURUGAN REPLY: Pupko is true that the well being advantages of sunshine could act, partly, by means of mitochondria. To exert organic results, mild should be absorbed by a chromophore. Mitochondria have such chromophores, together with cytochrome c oxidase (an electron shuttle within the electron-transport chain), which absorbs purple and near-infrared photons, ample in pure mild. These wavelengths improve the electrochemical potential throughout the internal mitochondrial membrane, energizing mitochondria and rising adenosine triphosphate synthesis.
For instance, photobiomodulation with near-infrared mild can rescue retinal operate in vivo and cut back Alzheimer’s pathology in mice. In people, transcranial photobiomodulation can enhance working reminiscence. In a 2024 human research, simply quarter-hour of publicity to 670-nanometer purple mild diminished postprandial glucose spikes by practically 30 %.
Mechanistic research, together with simulations and photoacoustic imaging, reveal how completely different wavelengths of sunshine work together with chromophores. A research utilizing photo voltaic simulators that matched the depth of summer time daylight demonstrated that mitochondrial responses to mild are cell-type-specific: epidermal keratinocytes confirmed mitochondrial injury beneath intense daylight, whereas dermal fibroblasts have been extra resilient. Daylight can due to this fact be broadly helpful, however its results rely strongly on wavelength, depth and publicity time, with ultraviolet mild carrying well-known dangers.
Mitochondria’s broader mild sensitivity might also assist clarify why time spent in nature feels restorative. Crops mirror a lot of the near-infrared spectrum, saturating inexperienced areas with low-energy, tissue-penetrating wavelengths.
In response to Weller: Throughout biology, mitochondria produce a number of the strongest electrical fields. As food-derived electrons circulate towards oxygen, the electron transport chain generates an electrochemical gradient throughout the internal mitochondrial membrane. The voltage potential spans a distance of solely about 5 nanometers, producing an electrical discipline on the order of 30 million volts per meter.
These immense electrical fields rise and fall with metabolic calls for and vitality circulate. Such fluctuations in electrical fields are anticipated to generate low-frequency electromagnetic indicators. Though it’s past the attain of in the present day’s devices, detecting such indicators from particular person mitochondria seems to be a necessary step towards totally understanding them as a social, energetic collective that transforms and regulates vitality throughout dwelling methods. And the composition of mitochondria suggests they might not solely generate but in addition reply to electromagnetic fields.
Maybe the perfect direct proof of biologically related fields on the scale of mitochondria is the transmitochondrial cristae alignment. This happens at intermitochondrial junctions, electron-dense contacts between two mitochondria.
ERRATA
“Analysis in Reverse,” by Charles C. Mann [September], ought to have referred to the Canadian Nationwide Breast Screening Research of most cancers.
“Folks Watching,” by Clarissa Brincat [Advances; October], ought to have quoted Laura Lewis as saying that people’ and chimpanzees’ shared primate ancestor lived round 5 million years in the past.
In “Prevention Intervention,” by Jyoti Madhusoodanan [Innovations in Alzheimer’s; October], OHSU’s identify must be Oregon Well being & Science College.
