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Category: biotech/medical – Page 5

A new reagent makes living brains transparent for deeper, non-invasive imaging

Making a living brain transparent and watching its neurons fire without disturbing their function—sounds like science fiction, doesn’t it? Yet the solution may already exist within our own bodies. In a paper published in Nature Methods, a research team led by Kyushu University introduces a new reagent called SeeDB-Live.

SeeDB-Live uses albumin—a common protein in blood serum—to clear tissue while preserving cellular function. The technique allows scientists to see deeper, brighter structures in both brain slices in a dish and living mice, achieving neural activity that was previously out of sight.

“This is the first time tissue clearing has been achieved without altering its biology,” says Takeshi Imai, professor at Kyushu University’s Faculty of Medical Sciences and the study’s senior author.

Diltiazem With Blood Thinners Tied to Bleeding Risk

Among patients with atrial fibrillation (AF) who initiated apixaban or rivaroxaban, the use of diltiazem was associated with a higher risk for serious bleeding complications than the use of metoprolol. The risk for bleeding was particularly elevated in patients who received diltiazem doses exceeding 120 mg daily.

Patients with atrial fibrillation who use diltiazem combined with apixaban or rivaroxaban face an increased risk for serious bleeding events compared with those who use metoprolol.

Human brain and AI speech recognition decode speech in similar step-by-step stages, study finds

Over the past decades, computer scientists have developed numerous artificial intelligence (AI) systems that can process human speech in different languages. The extent to which these models replicate the brain processes via which humans understand spoken language, however, has not yet been clearly determined.

Researchers at Columbia University, IBM Research and the Feinstein Institutes for Medical Research recently carried out a study aimed at comparing how automatic speech recognition (ASR) systems and the human brain decode speech. Their findings, published in Nature Machine Intelligence, suggest that activity in specific brain regions while people make sense of spoken language corresponds to specific stages in the processing of speech by AI models.

“The core mystery we wanted to solve is how the human brain performs the incredible computational feat of turning raw acoustic vibrations, the sounds of speech, into discrete linguistic meaning,” Nima Mesgarani, senior author of the paper, told Tech Xplore. “We now have AI systems that match human performance in transcribing speech, but we didn’t know if they were reaching those solutions independently or if they had converged on the same strategy as our biology.”

Molecular mechanisms of insulin resistance

1. Insulin stimulates tyrosine phosphorylation of the insulin receptor and of an endogenous substrate of approximately 185 kDa (insulin receptor substrate 1 or IRS-1). IRS-1 fulfills the criteria of a direct substrate of the insulin receptor, and tyrosine phosphorylation of IRS-1 leads to another step in insulin action, i.e., an association of phosphorylated IRS-1 with the enzyme PI3-kinase activating this enzyme. Using antipeptide antibodies to insulin receptor, to IRS-1 and to PI 3-kinase together with anti-phosphotyrosine antibodies it is possible to study insulin-stimulated insulin receptor phosphorylation, IRS-1 phosphorylation and the association/activation of IRS-1/PI 3-kinase. 2. In this review we describe alterations in these three early steps of insulin action after binding in animal models of insulin resistance, i.e., streptozotocin-induced diabetes (STZ diabetes), fasting, spontaneously hypertensive rats, the ob/ob mice, dexamethasone-treated rats, and the chronic effect of insulin on Fao cells in culture. 3. In states of insulin resistance with hypoinsulinemia (STZ diabetes and fasting) there is an increase in these early steps of insulin action. In animal models of insulin resistance with hyperinsulinemia there is a decrease in these steps of insulin action, indicating molecular post-receptor defects. Since we could reproduce the decrease in these three early steps of insulin action in cells in culture by chronic treatment with insulin, we postulate that these defects may be a consequence of the hyperinsulinemia of these animals.

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Targeted Remediation of the Ipsilesional Arm in Chronic Stroke: A Randomized Clinical Trial

Among patients with chronic stroke and severe contralesional impairment, targeted ipsilesional arm training supported significant and sustained improvements in ipsilesional motor performance vs best practice therapy.

Importance Ipsilesional upper-limb motor deficits after stroke are functionally important yet largely neglected in rehabilitation. Remediation may improve motor outcomes in individuals with severe contralesional arm hemiparesis.

Objective To determine whether training of the ipsilesional arm improves motor performance in chronic stroke with severe contralesional impairment and significant ipsilesional arm motor deficits.

Design, Setting, and Participants This 2-site, parallel-group randomized clinical trial with blinded outcome assessment was conducted from February 2019 to August 2024, with follow-up through 6 months posttreatment. Data analysis was performed from August 2024 through August 2025. The trial was conducted at outpatient research laboratories at Penn State College of Medicine and the University of Southern California among adults with radiologically confirmed unilateral middle cerebral artery stroke, severe contralesional upper-extremity impairment (Fugl-Meyer score ≤28), and ipsilesional motor deficits. Participants were randomly assigned with equal probability to 2 treatment groups and stratified by sex.

Golden lancehead genome reveals how genes responsible for venom toxins evolved

A research team led by scientists at the Butantan Institute in São Paulo, Brazil, has completed the most extensive genetic sequencing of a jararaca viper to date. The focus of the study was the genome of the golden lancehead (Bothrops insularis), particularly its venom genes. Since the species shares most of its genes with the other 48 species in the genus, the data serve as a reference for broader studies on the evolution of jararaca vipers and their toxins. The study is published in the journal Genome Biology and Evolution.

The golden lancehead was described in 1921 as a different species from the one known on the mainland, simply called jararaca (Bothrops jararaca). Isolated on Queimada Grande Island, off the coast of São Paulo, about 100,000 years ago, the population differed from its mainland counterparts to the point of separating into a new species.

In addition to having yellow skin, the golden lancehead is semi-arboreal and feeds on birds as an adult. Jararacas on the mainland, on the other hand, are dark in color and usually hunt small mammals, such as rats, on the ground. In 2021, B. jararaca became the first Brazilian snake to have its genome sequenced.

Neuronal VIP shapes intestinal stem cell activity and mucosal immunity

Intestinal homeostasis and regeneration rely on intestinal stem cells (ISCs). Li et al. identified neuronal vasoactive intestinal peptide (VIP) as a brake on ISCs through VIPR1 to limit regeneration. In Nature Immunology, Jakob et al. and Pirzgalska et al. further showed that VIP-VIPR1 signaling restrains secretory lineage expansion and balances immune responses.

Dolphin mass strandings in Patagonia linked to killer whales

In 2021 and 2023, hundreds of dolphins were stranded in shallow waters in San Antonio Bay in northern Patagonia. Some died, but many were returned safely to the sea. But what remained a mystery until now was how they ended up stuck on sandbanks in the first place. Now, a new study published in the journal Royal Society Open Science suggests that orcas may be to blame.

Mass strandings of common dolphins are rare and poorly understood in the southwestern Atlantic. Explanations for why they occur in other parts of the world include everything from disease and disorientation to human activities and being trapped by tides.

To discover what happened at San Antonio Bay, researchers from Argentina conducted necropsies (animal autopsies) on 38 dolphins from the 2021 event and gathered evidence from local community members. This included video footage from drones and tourist vessels uploaded to the eWHALE science platform, as well as interviews with fishermen and residents.

Open 3D Human Organ Atlas lets users explore anatomy in unprecedented detail

An international team of scientists and clinicians has announced the launch of a new open-access 3D portal that allows users to explore intact human organs in unprecedented detail—from the whole organ down to individual cells locally. The Human Organ Atlas, created using a powerful synchrotron imaging method, brings together some of the most detailed 3D images of human organs ever produced. It enables scientists, doctors, educators, students and the wider public to interactively “fly through” organs such as the brain, heart, lungs, kidney and liver, providing a new way of understanding human anatomy and human diseases.

Building on an initial release, the Human Organ Atlas (HOA) is now available in a greatly expanded form and can be accessed directly through a standard web browser, without specialized software. The technology is published in the journal Science Advances.

The Atlas is powered by an advanced imaging method called Hierarchical Phase-Contrast Tomography (HiP-CT), developed at the European Synchrotron (ESRF) in Grenoble, France, by an international team led by University College London (UCL), UK. HiP-CT uses the ESRF’s Extremely Brilliant Source—a new generation of synchrotron source—which is up to 100 billion times brighter than conventional hospital CT scanners.

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