New Delhi, As tuberculosis (TB) continues as the deadliest infectious cause of deaths globally, a new study has shown that artificial intelligence (AI)-enabled digital stethoscopes can help fill critical screening gaps, especially in hard-to-reach areas.
In a commentary published in the journal Med (Cell Press), global experts contended that stethoscopes combined with digital technology and AI can be a better option against the challenges faced in screening programmes, such as under-detection, high cost, and inequitable access.
“AI-enabled digital stethoscopes have demonstrated promising accuracy and feasibility for detecting lung and cardiovascular abnormalities, with promising results in early TB studies. Training and validation in diverse, high-burden settings are essential to explore the potential of this tool further,” said corresponding author Madhukar Pai from McGill University, Canada, along with researchers from the UAE, Germany, and Switzerland.
Despite advancements in screening and diagnostic tools, an estimated 2.7 million people with TB were missed by current screening programmes, as per data from the World Health Organization (WHO). Routine symptom screening is also likely to miss people with asymptomatic or subclinical TB.
While the WHO recently recommended several AI-powered computer-aided detection (CAD) software, as well as ultra-portable radiography hardware, higher operating costs and upfront hardware act as a deterrent.
This particularly appeared difficult in primary care settings and or among pregnant women due to radiation concerns.
At the same time, AI showed significant potential for screening, including applications beyond CAD of TB from radiographs, said the researchers.
“One application of AI for disease screening is to interpret acoustic (sound) biomarkers of disease, with potential to identify sounds that appear nonspecific or are inaudible to the human ear,” they added, while highlighting the potential of AI in detecting and interpreting cough biomarkers and lung auscultation to analyse breath sounds.
Studies from high-TB burden countries, including India, Peru, South Africa, Uganda, and Vietnam, highlighted that AI-enabled auscultation could hold promise as a TB screening and triage tool.
"AI digital stethoscopes may become useful alternatives to imaging-based approaches for TB screening, with the potential to democratise access to care for populations underserved by radiography," the researchers said."Importantly, AI digital stethoscopes offer a scalable, low-cost, and person-centered tool that could bring us closer to reaching TB case finding goals," they added. AI-powered digital stethoscopes show promise in bridging screening gaps | MorungExpress | morungexpress.com
The deep sea is cold, dark and under immense pressure. Yet life has found a way to prevail there, in the form of some of Earth’s strangest creatures.
Since deep-sea critters have adapted to near darkness, their eyes are particularly unique – pitch-black and fearsome in dragonfish, enormous in giant squid, barrel-shaped in telescope fish. This helps them catch the remaining rays of sunlight penetrating to depth and see the faint glow of bioluminescence.
Deep-sea fishes, however, typically start life in shallower waters in the twilight zone of the ocean (roughly 50–200 metres deep). This is a safe refuge to feed on plankton and grow while avoiding becoming a snack for larger predators.
Our new study, published in Science Advances, shows deep-sea fish larvae have evolved a unique way to maximise their vision in this dusky environment – a finding that challenges scientific understanding of vertebrate vision.
The nightmare of seeing in the twilight zone
The vertebrate retina, located at the back of the eye, has two main types of light-sensitive photoreceptor cells: rod-shaped for dim light and cone-shaped for bright light.
The rods and cones slowly change position inside the retina when moving between dim and bright conditions, which is why you temporarily go blind when you flick on the light switch on your way to the bathroom at night.
While vertebrates that are active during the daytime and predominantly inhabit bright light environments favour cone-dominated vision, animals that live in dim conditions, such as the deep sea or caves, have lost or reduced their cone cells in favour of more rods.
However, vision in twilight is a bit of a nightmare – neither rods nor cones are working at their best. This raises the question of how some animals, such as larval deep-sea fishes, can overcome the limitations of the cone-and-rod retina not only to survive but even to thrive in twilight conditions.
Starting where the fish start
To understand how newly born deep-sea fishes see, we had to start where they do: in the twilight zone of the ocean.
We caught larval fish from the Red Sea using fine-meshed nets towed from near the surface to a depth of around 200m. This way we got hold of three different species – the lightfish (Vinciguerria mabahiss) and the hatchetfish (Maurolicus mucronatus), both members of the dragonfishes, and a member of the lanternfishes, the skinnycheek lanternfish (Benthosema pterotum). Next, we studied what their photoreceptor cells looked like on the outside and how they were wired on the inside.
First, we used high-resolution microscopy to examine the cells’ shape in great detail. Then we investigated retinal gene expression to identify which vision genes were activated as the fish grew. Finally, we got some experts in computational modelling of visual proteins on board to simulate which wavelengths of light these tiny fishes may perceive.
By combining all the approaches, we were able to piece together a picture of how these animals see their world. This sounds relatively simple, but working with deep-sea fishes is anything but easy.
While these animals are generally thought of as monsters of the deep, in reality, most reach only about the size of a thumb – even when fully grown. They are also very fragile and difficult to get.
Working with larval specimens that are only a few millimetres long is even more difficult. However, by leveraging support from the deep-sea research community, we were fortunate enough to combine specimens from multiple research expeditions to piece together an unusually complete picture of visual development in these elusive animals.
So, what did we discover?
For decades, scientists have thought that, as vertebrates grow, the development of their retina follows a predictable pattern: cones form first, then rods. But the deep-sea fish we studied do not follow this rule.
We found that, as larvae, they mostly use a mix-and-match type of hybrid photoreceptor. The cells they are using early on look like rods but use the molecular machinery of cones, making them rod-like cones.
In some of the species we studied, these hybrid cells were a temporary solution, replaced by “normal” rods as the fish grew and migrated into deeper, darker waters.
However, in the hatchetfish, which spends its whole life in twilight, the adults keep their rod-like cone cells throughout life, essentially building their entire visual system around this extra type of cell.
Our research shows this is not a minor tweak to the system. Instead, it represents a fundamentally different developmental pathway for vertebrate vision.
Biology doesn’t fit into neat boxes
So why bother with these hybrid cells?
It seems that to overcome the visual limitations of the twilight zone, rod-like cones offer the best of both worlds: the light-capturing ability of rods combined with the faster, less bright-light sensitive properties of cones. For a tiny fish trying to survive in the murky midwater, this could mean the difference between spotting dinner or becoming it.
For more than a century, biology textbooks have taught that vertebrate vision is built from two clearly defined cell types. Our findings show these tidy categories are much more blurred.
Deep-sea fish larvae combine features of both rods and cones into a single, highly specialised cell optimised for life in between light and darkness. In the murky depths of the ocean, deep-sea fish larvae have quietly rewritten the rules of how eyes can be built, and in doing so, remind us that biology rarely fits into neat boxes.
(Photo: Eko Health, US) IANS
