A new system that could lead to diagnosing Alzheimer’s disease through a blood test was created by a group of researchers from the National University of Singapore (NUS). The system, called APEX (Amplified Plasmonic EXosome), is structured so that it can identify an early molecular marker of Alzheimer’s disease, the aggregated beta-amyloid (Aβ).
It is a technology that according to the researchers is “highly sensitive” and can provide an “accurate diagnosis, comparable to the PET image of the brain.” The latter is the standard for diagnosing Alzheimer’s disease. The difference lies in the fact that a test carried out with the APEX system, according to the researchers, would cost only $30, less than 1% of the cost that must be faced with PET imaging.
The system sees a direct analysis of the blood plasma sample and would also be very simple to use. The results of the two-year study that led to the creation of this method were published in Nature Communications.
However, one of the main features of this system is not in the cost or in the ease of use but in the fact that it allows, according to the researchers, very early diagnosis compared to the classical methods. Precisely the untimely diagnosis of Alzheimer’s disease is one of the main causes of the failure of therapies that need early intervention. A solution can arrive with the PET imaging system or with the cerebrospinal fluid test, but these are too expensive tests that are therefore not widely adopted.
The new test “captures” effectively, and measures the quantities, only the most significant amyloid-beta molecules in the blood sample and at the same time the more “early” ones, in order to analyze the first aggregated forms of this protein to allow detection of the Alzheimer’s even before the classic clinical symptoms appear.
A group of Australian researchers reveals that they have identified the fast cosmic waves related to an explosion that occurred in a distant galaxy 3.6 billion light-years away. This is a discovery that could be of fundamental importance to really understand the mysterious fast radio flashes.
The identification was carried out thanks to the observations of the Australian Square Kilometer Array Pathfinder (ASKAP) radio telescope of the Commonwealth Scientific and Industrial Research Organization (CSIRO), located in the region of Western Australia. This is a result that had long been expected in the astronomical community, a result that then resulted in a study published in Science.
Fast radio flashes are energy emissions caused by a cosmic explosion and are very difficult to intercept because they are emitted on long waves at the end of the electromagnetic spectrum. They are also very powerful so that they can develop in the same millisecond the same amount of energy that the Sun radiates in 10,000 years.
The first FRB was detected in 2007 and since then 85 have been identified, a number which however has not proved sufficient for a total understanding of the phenomenon. The researchers this time used a new method based on new software capable of calculating a billion measurements per second, which made it possible to “capture” these very fast flashes.
The new fast radio flash has been called FRB 180924 and is the first for which the position has been identified in a relatively precise manner. The lightning started from the galaxy Des J214425.25−405400.81. This galaxy was then photographed with the Very Large Telescope of the Southern European Observatory and its distance was measured with the Keck telescope of Hawaii.
Various hypotheses have been made regarding the explosion that these fast flashes generate and one of them sees the formation of a magnetar, a neutron star with a very pronounced magnetic field that is formed by the death of a very massive star. However, this discovery also reinforces the idea that there are two types of FRB, some repeated and others not, which may have completely different origins.
Those that are not repeated are much more difficult to identify but in this case, the researchers were able to identify with extreme precision the position of FRB 180924 locating it at 4000 parsecs (each parsec corresponds to about 3.26 light-years) from the galactic center of a galaxy distant from us 3.6 billion years ago.
A group of scientists has discovered that dimethyltryptamine (DMT), a molecule that is an active ingredient that is present in some hallucinogenic plants, is produced by two enzymes of neurons in the mammalian brain.
Dimethyltryptamine is historically used by various cultures during rituals that include hallucinogenic states, first of all those made by different indigenous peoples of the Americas for their religious or sacred ceremonies. It was then synthesized in the laboratory only in 1931.
One of the authors of the study, Jimo Borjigin, a researcher at the University of Michigan’s department of molecular and integrative physiology, turned to the work of another researcher, Rick Strassman. In the mid-1990s the latter conducted several experiments on humans subjected to DMT by intravenous injection, experiments that convinced him that the pineal gland in our body could naturally produce and secrete this substance. Borjigin resumed this work thinking that it would be relatively easy to locate the substance in this gland using a fluorescence detector. He therefore performed experiments on rats by collecting pineal gland samples from rodents and analyzing them in the laboratory. The analysis confirmed the presence of DMT, and this was already in 2013.
However, the researcher was not satisfied: he wanted to understand in what area of the body the substance was synthesized. He then worked with his student Jon Dean, lead author of a further study just published in Scientific Reports, performing experiments using a process called in situ hybridization that involves analyzing DNA strands to localize specific RNA sequences in a tissue.
They discovered that it is the enzymes of certain brain neurons that synthesize DMT. They also discovered that this substance did not end up only in the pineal gland but is also found in other parts of the brain, such as the neocortex and the hippocampus.
Finally, they discovered that the levels of this substance increase in rats subjected to cardiac arrest, which would justify the near-death experiences that in some ways can be considered similar to the hallucinogenic experiences that the substance produces when it is taken through plants.
According to a new study, long-term cryopreservation of human sperm would not greatly affect sperm viability. The research, conducted by Chuan Huang of the Changsa-Hunan sperm bank in China and presented at the 35th annual ESHRE meeting in Vienna, saw a retrospective analysis of 119,558 sperm samples taken from donors.
The same samples were divided into three groups: the cryopreserved ones for a period of between six months and five years, the cryopreserved ones from six to 10 years and the cryopreserved ones between 11 and 15 years. Considering the samples of the longest period, Huang and colleagues realized that, as a result of the thawing, the sperm survival rate was reduced by a few percentage points, settling in a range between 85% and 74%.
This is a decline, according to the same scholars, which has made little difference, however, as regards the clinical use of sperm in the context of assisted pregnancies.
According to Huang, these percentages would also be favored by the quality of the sperm preserved and the psychophysical condition of the donors. Despite these factors, according to the researchers, long-term sperm conservation by cryopreservation methods does not seem to affect birth rates.
However, many sperm banks establish strict time limits for sperm storage, up to a maximum of 10 years in some cases, although the scientific literature does not offer clear explanations and detailed research that can justify the imposition of these limits, not even with regards to any DNA damage.
A study conducted by researchers at Duke University clarifies some aspects regarding the question of the greater accumulation of fat in humans compared to other species of primates. In fact, in some ways, it is a mystery: why are humans so subject to obesity compared to many other species of apes and in general primates with which they share 99% of DNA?
Suffice it to say that most other primates have less than 9% body fat while for humans a fat level of between 14 and 31% can be considered healthy and normal. It is not just about eating styles and diets: there must be something genetic behind it. And in fact, the researchers have discovered that the greater aptitude to fat of the humans is connected to a molecular change in the modalities with which the DNA is packed inside the fat cells, a change that would have happened in some point of our past evolution.
This change has reduced our body’s ability to transform white fat, called “bad” fat, into brown fat, which is then dubbed the “good” fat. The study, published in Genome Biology and Evolution, describes the results achieved by Devi Swain-Lenz and Greg Wray, two Duke biologists during experiments on fat samples taken from humans, chimpanzees and Rhesus macaques. By analyzing the genome of the samples, they identified a recurrent DNA fragment that underlies the conversion of fat from one cell type to another.
This fragment would still be fully operational in monkeys while in humans it would have remained “hidden” making us lose the ability to maximize the process that sees the fat cells being diverted to “good” fat. “We are stuck along the path of white fat,” reports Swain-Lenz.
The research could be useful to understand the possibilities of activation or deactivation of some genes to reactivate the process and therefore counteract obesity, but the same researchers report that at the research level we are still very far from such a goal: “I don’t think it’s as simple as pushing a switch: if it was, we would have understood it a long time ago,” reports Swain-Lenz.