Comment

Comment by Dr. Krishna Kumari Challa on June 21, 2022 at 9:07am

Scientists transplant human photoreceptors to successfully recover daylight perception in mice

Transplantation of photoreceptor cells is a promising intervention that in the future could help recover vision in people with blinding diseases. A team of researchers developed a robust method to produce high numbers of human photoreceptor cells. The researchers show that such human photoreceptors can incorporate in bulk into partially degenerated mouse retinas. The incorporated photoreceptors developed characteristics of normal photoreceptors and allowed mice with damaged eyesight to detect daylight.

The new study represents a step forward in an effort to bring photoreceptor transplantations to patients with blinding diseases.

To massively increase the number of incorporated photoreceptors, the scientists optimized multiple critical factors. They established that the age of transplanted photoreceptors is decisive.

The team also found that the integration into the retina needs a longer time. 

The interaction with the remaining, undamaged cells in the mouse retina turned out to be a key factor. About 30% of the cells in the retina are other cells that support the work of photoreceptors. In this case, researchers clearly saw that the interaction of transplanted cells with host retinal cells was crucial for successful incorporation and maturation. Some of these remaining cells provided a scaffold for the new photoreceptors and helped them organize correctly.

To produce photoreceptors, the team used stem cells to grow mini-retinas in a laboratory dish.

Obtaining a pure population of photoreceptors is yet another challenge. To address it researchers developed a new stem cell line in which cone photoreceptor cells have special tags. These tags do not interfere with their function but allow us to robustly sort photoreceptors from the rest of the cells in the mini-retinas.

Such induced pluripotent stem cell lines provide a virtually unlimited source of photoreceptors and can potentially be used in future clinical applications.

In this study, the team focused on mice with partially degenerated retinas that lacked only one out of two types of photoreceptors. The mice had only damaged cones, which are responsible for daylight vision, a situation similar to several blinding diseases in human patients. 

https://www.jci.org/articles/view/154619

Comment by Dr. Krishna Kumari Challa on June 21, 2022 at 8:51am

Scientists develop antimicrobial, plant-based food wrap designed to replace plastic

Aiming to produce environmentally friendly alternatives to plastic food wrap and containers, a  scientist has developed a biodegradable, plant-based coating that can be sprayed on foods, guarding against pathogenic and spoilage microorganisms and transportation damage.

The scalable process could potentially reduce the adverse environmental impact of  plastic food packaging as well as protect human health.

Their article, published in the science journal Nature Food, describes the new kind of packaging technology using the polysaccharide/biopolymer-based fibers. Like the webs cast by the Marvel comic book character Spider-Man, the stringy material can be spun from a heating device that resembles a hair dryer and "shrink-wrapped" over foods of various shapes and sizes, such as an avocado or a sirloin steak. The resulting material that encases food products is sturdy enough to protect bruising and contains antimicrobial agents to fight spoilage and pathogenic microorganisms such as E. coli and listeria.

The research paper includes a description of the technology called focused rotary jet spinning, a process by which the biopolymer is produced, and quantitative assessments showing the coating extended the shelf life of avocados by 50 percent. The coating can be rinsed off with water and degrades in soil within three days, according to the study.

The new packaging is targeted at addressing a serious environmental issue: the proliferation of petroleum-based plastic products in the waste stream.

 High-throughput coating with biodegradable antimicrobial pullulan fibres extends shelf life and reduces weight loss in an avocado model, Nature Food (2022). DOI: 10.1038/s43016-022-00519-6

Comment by Dr. Krishna Kumari Challa on June 21, 2022 at 8:42am

Lack of diversity of microorganisms in the gut or elevated gut metabolites implicated in heart failure severity

Some people who experience heart failure have less biodiversity in their gut or have elevated gut metabolites, both of which are associated with more hospital visits and greater risk of death, according to a systematic review of research findings.

The gut microbiome is a delicately balanced ecosystem comprised primarily of bacteria as well as viruses, fungi and protozoa. The microbiome can affect cardiovascular disease, which is a leading cause of death in many parts of the world.

For their overview, the investigators looked at seven years of genetic, pharmacologic and other types of research findings from around the world to generate a wide perspective on how the microbiome can influence heart failure. The investigators zeroed in on one harmful metabolite, trimethylamine-N-oxide (TMAO), that can be produced by churning gut microbiota when full-fat dairy products, egg yolks and red meat are consumed.

The Heart and Gut Relationship: A Systematic Review of the Evaluation of the Microbiome and Trimethylamine-N-Oxide (TMAO) in Heart Failure, Heart Failure Reviews (2022). DOI: 10.1007/s10741-022-10254-6

Comment by Dr. Krishna Kumari Challa on June 21, 2022 at 8:24am

Keeping objects levitated by sound airborne despite interference

A team of researchers  has developed a way to keep objects levitated by sound waves airborne when other objects interfere with the levitation path. In their paper published in the journal Science Advances, the group describes their self-correcting levitation system.

Prior research has shown that it is possible to levitate objects by firing sound waves at them. Because sound waves are nothing more than air particles moving together in a certain way, the object being levitated will fall if an object interferes with the sound waves. In this new effort, the researchers developed new features to address this problem.

To protect the sound waves from interference, the researchers increased the number of speakers used—in their work, they used 256. They also added software to control each of the speakers. The speakers were arranged in a grid and objects were levitated by specifically shaped sound waves. By programming the speakers in specific ways, the team was able to get the system to work together to keep an object above the grid in the air despite interruptions. If some of the sound waves were blocked, other sound waves were redirected to take their place.

The researchers proved their system was viable by testing it using a 3D-printed white rabbit as an interference object. Objects were levitated around the rabbit regardless of its location. In one experiment, the researchers levitated beads around the rabbit that formed into a flying butterfly. They also levitated a piece of clear fabric that they used as a screen for projection of the rabbit they had printed. And they levitated a single drop of water over a glass of water, showing that their system would work even when the interfering object was a jiggling glass of liquid.

 Ryuji Hirayama et al, High-speed acoustic holography with arbitrary scattering objects, Science Advances (2022). DOI: 10.1126/sciadv.abn7614

Comment by Dr. Krishna Kumari Challa on June 18, 2022 at 10:24am

Damage to Brain Network Curbs Urge to Smoke

A study finds that injuries to certain areas of the brain were associated with quitting smoking more quickly, easily, and with no cravings.

Astudy of people who effortlessly quit smoking after a stroke or other brain injury—and of those who suffered an injury but then kept smoking—has pinpointed a brain network involved in addiction, researchers reported June 13 in Nature Medicine. Experts say the findings may help identify targets for therapies that could treat addictions.  

https://www.the-scientist.com/news-opinion/damage-to-brain-network-...

Comment by Dr. Krishna Kumari Challa on June 18, 2022 at 9:37am

Bluetooth signals can be used to identify and track smartphones

Comment by Dr. Krishna Kumari Challa on June 18, 2022 at 9:33am

The idea of transplanting a patient with their organ donor's immune system has been around for decades, but it has been difficult to implement. Transplants of stem cells from bone marrow provide the patient with a genetically new immune system, as some of the bone marrow stem cells mature into immune cells in the blood. First developed for people with blood cancers, stem cell transplants carry the risk of the new immune cells attacking the recipient's body, a complication called graft-versus-host disease. Severe GVHD can be fatal.

Researchers working with adult patients have performed sequential stem cell and kidney transplants from living donors. When the donor was half-matched they had partial success, but patients were either unable to completely discontinue immune-suppressing drugs after transplant, or—in other trials not conducted at Stanford—they had unacceptably high risks of severe GVHD.

This new work introduced refinements that greatly improve the success of the two-transplant combination with much lower risk. This key innovation is a change in how the donor's stem cells are processed.

https://www.nejm.org/doi/full/10.1056/NEJMoa2117028

After stem cells are removed from the donor's body, technicians perform alpha-beta T cell depletion, which removes the type of immune cells that cause GVHD. Bertaina's team had showed that alpha-beta T cell depletion—which she developed while working in Italy prior to coming to Stanford—makes stem cell transplants safer and enables genetically half-matched transplants. The protocol is relatively gentle, making it safe for children with immune disorders who are too medically fragile for a traditional stem cell transplant. The alpha-beta T cells recover in the patient after 60 to 90 days, meaning they regain full immune function.

Part 2

Comment by Dr. Krishna Kumari Challa on June 18, 2022 at 9:30am

Transplanting kidneys without need for immune-suppressing drugs

Physicians  have developed a way to provide pediatric kidney transplants without immune-suppressing drugs. Their key innovation is a safe method to transplant the donor's immune system to the patient before surgeons implant the kidney.

The medical team has named the two-transplant combination a "dual immune/solid organ transplant," or DISOT. A scientific paper describing the first three DISOT cases, all performed at Lucile Packard Children's Hospital Stanford, published online June 15 in the New England Journal of Medicine. 

 This innovation removes the possibility that the recipient will experience immune rejection of their transplanted organ. (Organ rejection is the most common reason for a second organ transplant.) The new procedure also rids recipients of the substantial side effects of a lifetime of immune-suppressing medications, including increased risks for cancer, diabetes, infections and high blood pressure.

The first three DISOT patients were children with a rare immune disease, but the team is expanding the types of patients who could benefit.

The doctors anticipate that the protocol will eventually be available to many people needing kidney transplants, starting with children and young adults, and later expanding to older adults. The researchers also plan to investigate DISOT's utility for other types of solid-organ transplants.

The scientific innovation from the team has another important benefit: It enables safe transplantation between a donor and recipient whose immune systems are genetically half-matched, meaning children can receive stem cell and kidney donations from a parent.

Part 1

Comment by Dr. Krishna Kumari Challa on June 18, 2022 at 9:12am

Electrons take the fast and slow lanes at the same time

Imagine a road with two lanes in each direction. One lane is for slow cars, and the other is for fast ones. For electrons moving along a quantum wire, researchers have discovered that there are also two "lanes," but electrons can take both at the same time!

Current in a wire is carried by the flow of electrons. When the wire is very narrow (one-dimensional, 1D) then electrons cannot overtake each other, as they strongly repel each other. Current, or energy, is carried instead by waves of compression as one particle pushes on the next.

It has long been known that there are two types of excitation for electrons, as in addition to their charge they have a property called spin. Spin and charge excitations travel at fixed, but different speeds, as predicted by the Tomonaga-Luttinger model many decades ago. However, theorists are unable to calculate what precisely happens beyond only small perturbations, as the interactions are too complex. The Cambridge team has measured these speeds as their energies are varied, and find that a very simple picture emerges (now published in the journal Science Advances). Each type of excitation can have low or high kinetic energy, like cars on a road, with the well-known formula E=1/2 mv², which is a parabola. But for spin and charge the masses m are different, and, since charges repel and so cannot occupy the same state as another charge, there is twice as wide a range of momentum for charge as for spin. The results measure energy as a function of magnetic field, which is equivalent to momentum or speed v, showing these two energy parabolas, which can be seen in places all the way up to five times the highest energy occupied by electrons in the system.

It's as if the cars (like charges) are traveling in the slow lane but their passengers (like spins) are going more quickly, in the fast lane! Even when the cars and passengers slow down or speed up, they still remain separate!

These results now open the question of whether this spin-charge separation of the whole electron sea remains robust beyond 1D, e.g., in high-temperature superconducting materials. It may also now be applied to logic devices that harness spin (spintronics), which offer a drastic reduction (by three orders of magnitude!) of the energy consumption of a transistor, simultaneously improving our understanding of quantum matter as well as offering a new tool for engineering quantum materials

Pedro M. T. Vianez et al, Observing separate spin and charge Fermi seas in a strongly correlated one-dimensional conductor, Science Advances (2022). DOI: 10.1126/sciadv.abm2781

Comment by Dr. Krishna Kumari Challa on June 18, 2022 at 8:40am

Which cells are involved in heart repair and how they communicate with each other

Thousands of people suffer heart attacks every year. In this case, the heart muscle is no longer supplied with sufficient blood and oxygen, and part of the heart muscle tissue dies and becomes scarred. The consequences can range from massive cardiac insufficiency to heart failure. Unlike the liver, the heart of an adult human being cannot regenerate. However, it is able to initiate repair processes. Exactly how these repair processes take place has not been known until now. Therefore, there are still no drugs that can specifically promote healing.

Now a research team has found out which cells are involved in heart repair and how they communicate with each other. The researchers have discovered a new messenger substance that controls wound healing, thus revealing an approach for a new therapy. The research has been published in Science.

The focus of the study is the receptor KIT. The protein is produced by various cells, including the hematopoietic stem cells  in the bone marrow. Here, KIT plays an important role as a binding site for the so-called stem cell factor. This messenger substance activates the KIT-positive stem cells and causes them to develop into the various cells of the blood. KIT-positive cells are also found in the heart.

"However, these are not stem cells, as long suspected, but vascular cells. The KIT-positive vascular cells ensure that new heart vessels form after a heart attack. However, the stem cell factor necessary for KIT activation can barely be detected in the heart. The researchers have now resolved this contradiction. They discovered a new messenger substance in the heart that can also bind precisely to the KIT receptor and set the repair process in motion: the protein meteorin-like (METRNL).

After a heart attack, the immune system reacts with an inflammatory response . The inflammatory cells produce METRNL, which stimulates the KIT-positive vascular cells to form new blood vessels.

Studies in the mouse model showed that without METRNL, heart repair no longer worked. In contrast, when mice were treated with METRNL, new vessels formed in the infarct area. This alleviates scarring and prevents severe heart failure.

The newly discovered messenger substance could now be the decisive building block to a drug that specifically supports heart repair.

 Marc R. Reboll et al, Meteorin-like promotes heart repair through endothelial KIT receptor tyrosine kinase, Science (2022). DOI: 10.1126/science.abn3027

• ‹ Previous
• 1
• …
• 261
• 262
• 263
• 264
• 265
• …
• 855
• Next ›
• Page