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Diseases and Conditions

Ancient DNA Uncovers a Forgotten Chapter in Leprosy’s History in the Americas

Leprosy’s tale stretches from 5,000-year-old skeletons in Eurasia to a startling 4,000-year-old case in Chile, revealing that the rare strain Mycobacterium lepromatosis haunted the Americas millennia before Europeans arrived. Armed with cutting-edge ancient-DNA sleuthing, scientists have pieced together remarkably well-preserved genomes that challenge the idea of leprosy as purely a colonial import and hint that the disease may have homegrown American roots awaiting confirmation by future finds.

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The discovery of ancient DNA in human bones has revolutionized our understanding of diseases that have plagued humans for centuries. Recently, researchers have uncovered evidence that leprosy, also known as Hansen’s Disease, had a presence in the Americas long before European colonization. This finding challenges the common assumption that leprosy was introduced to the continent by European settlers.

Leprosy is a chronic disease caused by either Mycobacterium leprae or Mycobacterium lepromatosis. While M. leprae is the more commonly known pathogen, M. lepromatosis has been found in a rare form of the disease. The discovery of ancient DNA from 4000-year-old skeletons in Chile suggests that M. lepromatosis was present in the Americas thousands of years ago.

This finding is significant because it reveals a previously unknown chapter in leprosy’s history. Historically, leprosy has been documented in Europe and Asia for thousands of years, but its presence in the Americas before European colonization had gone undetected. The discovery of ancient DNA from M. lepromatosis in Chile provides evidence that this disease was present in the Americas at least 4000 years ago.

The study of ancient DNA has become a valuable tool for researchers to uncover the history of diseases that have affected humans over time. By analyzing ancient bone samples, researchers can identify the presence of pathogens and reconstruct their evolutionary history. In this case, the discovery of M. lepromatosis in Chile provides a fascinating example of how ancient DNA can shed new light on the history of a disease.

Further research is needed to understand the full extent of leprosy’s history in the Americas. The discovery of M. lepromatosis in Chile has opened up new avenues for research, and it is likely that more cases will be identified in the coming years. By studying ancient DNA from other time periods and contexts, researchers can gain a better understanding of how leprosy was transmitted and evolved over time.

Ultimately, the discovery of M. lepromatosis in Chile highlights the importance of studying ancient DNA to uncover the history of diseases that have affected humans for centuries. By doing so, we can gain a deeper understanding of how these diseases were transmitted and evolved over time, and perhaps even find new ways to prevent or treat them.

Brain Tumor

AI Tool Tracks Lung Tumors as You Breathe, Potentially Saving Lives

An AI system called iSeg is reshaping radiation oncology by automatically outlining lung tumors in 3D as they shift with each breath. Trained on scans from nine hospitals, the tool matched expert clinicians, flagged cancer zones some missed, and could speed up treatment planning while reducing deadly oversights.

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The article describes how a team of Northwestern Medicine scientists has developed an innovative AI tool called iSeg that can accurately outline lung tumors on CT scans, even as they move with each breath. This is a critical factor in planning radiation treatment, which half of all cancer patients in the US receive during their illness. The study found that iSeg consistently matches expert outlines across hospitals and scan types, and also flags additional areas that some doctors may miss – areas linked to worse outcomes if left untreated.

The AI tool was trained using CT scans and doctor-drawn tumor outlines from hundreds of lung cancer patients treated at nine clinics within the Northwestern Medicine and Cleveland Clinic health systems. The study’s authors believe that iSeg can help reduce delays, ensure fairness across hospitals, and potentially identify areas that doctors might miss – ultimately improving patient care and clinical outcomes.

The research team is now testing iSeg in clinical settings, comparing its performance to physicians in real time. They are also integrating features like user feedback and working to expand the technology to other tumor types, such as liver, brain, and prostate cancers. The team envisions this as a foundational tool that could standardize and enhance how tumors are targeted in radiation oncology.

The study was published today (June 30) in the journal npj Precision Oncology.

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Autism

Unpacking the Gene That Hijacks Fear: How PTEN Rewires the Brain’s Anxiety Circuit

Deleting a gene called PTEN in certain brain cells disrupts the brain’s fear circuitry and triggers anxiety-like behavior in mice — key traits seen in autism. Researchers mapped how this genetic tweak throws off the brain’s delicate balance of excitation and inhibition in the amygdala, offering deep insights into how one gene can drive specific ASD symptoms.

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The gene PTEN has emerged as one of the most significant autism risk genes. Variations in this gene are found in a significant proportion of people with autism who also exhibit brain overgrowth. Researchers at the Max Planck Florida Institute for Neuroscience have discovered how loss of this gene rewires circuits and alters behavior, leading to increased fear learning and anxiety in mice – core traits seen in ASD.

PTEN has been linked to alterations in the function of inhibitory neurons in the development of ASD. The researchers focused on the changes in the central lateral amygdala driven by loss of PTEN in a critical neuronal population – somatostatin-expressing inhibitory neurons. They found that deleting PTEN specifically in these interneurons disrupted local inhibitory connectivity in the amygdala by roughly 50% and reduced the strength of the remaining inhibitory connections.

This diminished connectivity between inhibitory connections within the amygdala was contrasted by an increase in the strength of excitatory inputs received from the basolateral amygdala, a nearby brain region that relays emotionally-relevant sensory information to the amygdala. Behavioral analysis demonstrated that this imbalance in neural signaling was linked to heightened anxiety and increased fear learning, but not alterations in social behavior or repetitive behavior traits commonly observed in ASD.

The results confirm that PTEN loss in this specific cell type is sufficient to induce specific ASD-like behaviors and provide one of the most detailed maps to date of how local inhibitory networks in the amygdala are affected by genetic variations associated with neurological disorders. Importantly, the altered circuitry did not affect all ASD-relevant behaviors – social interactions remained largely intact – suggesting that PTEN-related anxiety and fear behaviors may stem from specific microcircuit changes.

By teasing out the local circuitry underlying specific traits, researchers hope to differentiate the roles of specific microcircuits within the umbrella of neurological disorders, which may one day help in developing targeted therapeutics for specific cognitive and behavioral characteristics. In future studies, they plan to evaluate these circuits in different genetic models to determine if these microcircuit alterations are convergent changes that underlie heightened fear and anxiety expression across diverse genetic profiles.

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Allergy

The Hidden Dangers of Fire Smoke Exposure

Smoke from wildfires and structural fires doesn t just irritate lungs it actually changes your immune system. Harvard scientists found that even healthy people exposed to smoke showed signs of immune system activation, genetic changes tied to allergies, and even toxic metals inside their immune cells.

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The dangers of fire smoke exposure are well-documented, but until now, the full extent of its impact on our bodies has been unclear. A recent study led by researchers at Harvard T.H. Chan School of Public Health reveals that fire smoke can alter our immune system on a cellular level, leaving lasting changes and increasing our risk of serious health problems.

The study examined blood samples from 31 individuals who had been exposed to fire smoke and compared them to those from 29 non-exposed individuals. The results showed significant changes in the immune cells of those who had been exposed to smoke. These changes included an increase in memory CD8+ T cells, which are crucial for long-term immunity against pathogens, as well as elevated activation and chemokine receptor biomarkers that indicate inflammation and immune activity.

The researchers also found changes in 133 genes related to allergies and asthma in the individuals who had been exposed to smoke. Moreover, their immune cells were more likely to be bound with toxic metals like mercury and cadmium, which can further harm our health.

“This study fills a critical knowledge gap by showing exactly how fire smoke exposure can damage the body,” said Kari Nadeau, corresponding author of the study and chair of the Department of Environmental Health. “Our findings have significant implications for public health leaders and clinicians who need to respond to the growing threat of wildfires.”
The study’s lead author, Mary Johnson, added that the immune system is extremely sensitive to environmental exposures like fire smoke, even in healthy individuals. Knowing exactly how smoke exposure can harm our bodies may help us detect immune dysfunction earlier and pave the way for new therapeutics to mitigate or prevent the health effects of smoke exposure.

The researchers also noted that their study could inform environmental and public health policies and investments, such as increasing public awareness about the dangers of smoke exposure and the importance of following evacuation procedures during wildfires.
The study was funded by several organizations, including the National Institute of Environmental Health Sciences, the National Heart, Lung, and Blood Institute, and the San Francisco Cancer Prevention Foundation.

In conclusion, this study highlights the need for increased caution when it comes to fire smoke exposure. By understanding the full extent of its impact on our bodies, we can take steps to protect ourselves and others from its toxic effects.

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