Brain's on-off thirst switch identified

January 27, 2015

Brains on-off

Washington, Jan 27: Scientists have identified neurons that trigger our sense of thirst and those that turn it off.

For years, researchers have suspected that thirst is regulated by neurons in the subfornical organ (SFO), in the hypothalamus. But it has been difficult to pinpoint exactly which neurons are involved.

“When researchers used electrical current to stimulate different parts of the SFO of mice, they got confusing results,” said lead author Yuki Oka, a postdoctoral research scientist in the laboratory of Charles S Zuker, a Howard Hughes Medical Institute Investigator at Columbia University Medical Center (CUMC).

The CUMC team hypothesised that there are at least two types of neurons in the SFO, including ones that drive thirst and others that suppress it.

“Those electrostimulation experiments were probably activating both types of neurons at once, so they were bound to get conflicting results,” said Oka.

To test their hypothesis, Oka and Zuker turned to optogenetics, a more precise technique for controlling brain activity. With optogenetics, researchers can control specific sets of neurons in the brain after inserting light-activated molecules into them.

Shining light onto these molecules turns on the neurons without affecting other types of neurons nearby.

These “mind-control” experiments revealed two types of neurons in the SFO that control thirst: CAMKII neurons, which turn thirst on, and VGAT neurons, which turn it off.

When the researchers turned on CAMK11 neurons, mice immediately began to seek water and to drink intensively.

This behaviour was as strong in well-hydrated mice as in dehydrated ones. Once the neurons were shut off – by turning off the light – the mice immediately stopped drinking.

The researchers also found that light-stimulation of the CAMKII neurons did not induce feeding behaviour. In addition, light-induced thirst was specific for water and did not increase the animals’ consumption of other fluids, including glycerol and honey.

Similar experiments with VGAT neurons showed that these neurons act to turn off thirst. When the researchers turned on these neurons with light, dehydrated mice immediately stopped drinking, even if they were drinking water.

“Together, these findings show that the SFO is a dedicated brain system for thirst,” said Oka.

“The SFO is one of few neurological structures that is not blocked by the blood-brain barrier – it’s completely exposed to the general circulation,” said Oka.

“This raises the possibility that it may be possible to develop drugs for conditions related to thirst,” Oka added.

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News Network
February 26,2020

New York, Feb 26:  A new wearable sensor that works in conjunction with artificial intelligence (AI) technology could help doctors remotely detect critical changes in heart failure patients days before a health crisis occurs, says a study.

The researchers said the system could eventually help avert up to one in three heart failure readmissions in the weeks following initial discharge from the hospital and help patients sustain a better quality of life.

"This study shows that we can accurately predict the likelihood of hospitalisation for heart failure deterioration well before doctors and patients know that something is wrong," says the study's lead author Josef Stehlik from University of Utah in the US.

"Being able to readily detect changes in the heart sufficiently early will allow physicians to initiate prompt interventions that could prevent rehospitalisation and stave off worsening heart failure," Stehlik added.

According to the researchers, even if patients survive, they have poor functional capacity, poor exercise tolerance and low quality of life after hospitalisations.

"This patch, this new diagnostic tool, could potentially help us prevent hospitalizations and decline in patient status," Stehlik said.

For the findings, published in the journal Circulation: Heart Failure, the researchers followed 100 heart failure patients, average age 68, who were diagnosed and treated at four veterans administration (VA) hospitals in Utah, Texas, California, and Florida.

After discharge, participants wore an adhesive sensor patch on their chests 24 hours a day for up to three months.

The sensor monitored continuous electrocardiogram (ECG) and motion of each subject.

This information was transmitted from the sensor via Bluetooth to a smartphone and then passed on to an analytics platform, developed by PhysIQ, on a secure server, which derived heart rate, heart rhythm, respiratory rate, walking, sleep, body posture and other normal activities.

Using artificial intelligence, the analytics established a normal baseline for each patient. When the data deviated from normal, the platform generated an indication that the patient's heart failure was getting worse.

Overall, the system accurately predicted the impending need for hospitalization more than 80 per cent of the time.

On average, this prediction occurred 10.4 days before a readmission took place (median 6.5 days), the study said.

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Agencies
June 27,2020

After admitting that the world may have a COVID-19 vaccine within one year or even a few months earlier, the World Health Organisation (WHO) on Friday said that UK-based AstraZeneca is leading the vaccine race while US-based pharmaceutical major Moderna is not far behind.

WHO Chief Scientist Soumya Swaminathan stated that the AstraZeneca's coronavirus vaccine candidate is the most advanced vaccine currently in terms of development.

"I think AstraZeneca certainly has a more global scope at the moment in terms of where they are doing and planning their vaccine trials," she told the media.

AstraZeneca's Covid-19 vaccine candidate developed by researchers from the Oxford University will likely provide protection against the disease for one year, the British drug maker's CEO told Belgian radio station Bel RTL this month.

The Oxford University last month announced the start of a Phase II/III UK trial of the vaccine, named AZD1222 (formerly known as ChAdOx1 nCoV-19), in about 10,000 adult volunteers. Other late-stage trials are due to begin in a number of countries.

Last week, Swaminathan had said that nearly 2 billion doses of the COVID-19 vaccine would be ready by the end of next year.

Addressing the media from Geneva, she said that "at the moment, we do not have a proven vaccine but if we are lucky, there will be one or two successful candidates before the end of this year" and 2 billion doses by the end of next year.

Scientists predict that the world may have a COVID-19 vaccine within one year or even a few months earlier, said the Director-General of the World Health Organization even as he underlined the importance of global cooperation to develop, manufacture and distribute the vaccines.

However, making the vaccine available and distributing it to all will be a challenge and will require political will, WHO chief Tedros Adhanom Ghebreyesus said on Thursday during a meeting with the European Parliament's Committee for Environment, Public Health and Food Safety.

One option would be to give the vaccine only to those who are most vulnerable to the virus.

There are currently over 100 COVID-19 vaccine candidates in various stages of development.

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Agencies
June 20,2020

At a time when the country is yet to recover from the shock of losing 20 Indian soldiers in a violent clash with the Chinese People's Liberation Army (PLA) troops in Ladakh's Galwan Valley, another shocker has come to light with news coming of a malware hitting the Indian Railways network and snooping its data for foreign countries, including train movements, sources in the intelligence agencies said on Friday.

Meanwhile, Railways Board Chairman V K Yadav said that the national transporter keeps on receiving malware security threats and the engineers in the railways keep on taking all precautions and keeps on updating the firewalls to prevent data theft.

The news comes a day after the Dedicated Freight Corridor Corporation Limited (DFCCIL) decided to terminate the 417-km signalling project worth Rs 471 crore with Chinese firm Beijing National Railway Research and Design Institute of Signal and Communication Group Company Limited (BNRRDISC) due to non-performance.

According to intelligence agency sources, the system of the Railways has been hit by the APT 36 Malware campaign. The source said that the intel agencies have also alerted the Railway Board to instantly disconnect the system with the Internet and change the password immediately.

The source said the APT 36 Malware is connected to Pakistan, which is a close ally of China. The source further said that following the red flag from the intel agencies, the system of a senior Principal Executive Director of the Railways, working in its vigilance department, has been taken for cleaning the malware threat.

As per the source, through the APT 36 Malware campaign, data stored in the Indian Railways systems were being stolen and stored in foreign locations, including the movement of the trains.

He further claimed that the APT 36 Malware also tried to take defence movement data. 

The source said the APT 36 Malware effect was reported from at least four systems of the Indian Railways.

Responding to queries, the Railways Board Chairman said: "Whether it is our systems or the IRCTC, we continuously update it with firewalls, and it is an ongoing process as we get the updates." 

Yadav said that our system is updated time to time. "We get malware threat on a regular basis. And we look at it continuously," he said. 

When pressed further about the malware threat in four railways systems, he said: "It has not come to our notice that some information has been leaked. Our systems are secure and our engineers keep on working on it."

According to intel sources, besides Railways, there was also malware threat in the defence, central police organisations, education and healthcare sectors, the source said.

In view of the threat, the intel agencies have asked the departments concerned to change the passwords of emails and online services from secure computers, format the hard-disk of the affected computers after taking back-up and re-install the operating systems and other softwares.

Sources in the Railways had said on Thursday that DFFCIL, which is looking after the work of the Dedicated Freight Corridor Project, has decided to terminate the tender with BNRRDISC.

A source in the Railway Ministry said that it has informed the Railway Board and the World Bank to take the final decision in the matter.

The source said the project was awarded to the Chinese firm in 2016 for signalling and telecommunication work on the 417-km Kanpur-Deen Dayal Upadhyaya section of the Eastern Dedicated Freight Corridor (EDFC). 

The source disclosed that the contract was awarded to the Beijing National Railway Research and Design Institute in June 2016. The source further said that even after four years, the progress in the project was only 20%. The issues that led to the termination of the project are reluctance by the company to furnish technical documents, as per the contract agreement, such as logic design of electronic interlocking.

The source further said that other issues like non-availability of their engineers and authorised personnel on site were a serious constraint. Even physical work could not progress as they have no tie-up with local agencies. 

The 3,373-km DFC, a flagship project of the Railways, aims to augment rail transport capacity to meet the growing requirement of movement of goods by segregating freight from passenger traffic.

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