Fish eyes may hold key to blindness cure: study

March 11, 2017

Washington, Mar 11: Scientists, including one of Indian-origin, have identified a chemical signal in the zebrafish brain that helps it regenerate retina, a finding that may help cure blindness in humans.

fisheye

The discovery raises the possibility that human retinas can be induced to regenerate, naturally repairing damage caused by degenerative retinal diseases and injury, including age-related macular degeneration and retinitis pigmentosa, researchers said.

"The prevailing belief has been that the regeneration process in fish retinas is triggered by secreted growth factors, but our results indicate that the neurotransmitter GABA might initiate the process instead," said James Patton, Professor at Vanderbilt University in the US.

"All the regeneration models assume that a retina must be seriously damaged before regeneration takes place, but our studies indicate that GABA can induce this process even in undamaged retinas," said Patton.

It turns out that the structure of the retinas of fish and mammals are basically the same.

Although the retina is very thin - less than 0.5 millimetres thick - it contains three layers of nerve cells: photoreceptors that detect the light, horizontal cells that integrate the signals from the photoreceptors and ganglion cells that receive the visual information and route it to the brain.

In addition, the retina contains a special type of adult stem cell, called Muller glia, that span all three layers and provide mechanical support and electrical insulation. In fish retinas, they also play a key role in regeneration.

When regeneration is triggered, the Muller glia dedifferentiate, begin proliferating, and then differentiate into replacements for the damaged nerve cells. Muller glia are also present in mammalian retinas, but do not regenerate.

Graduate student Mahesh Rao got the idea that GABA - normally a fast-acting neurotransmitter best known for its role of calming nervous activity by inhibiting nerve transmission in the brain - might be the trigger for retinal regeneration.

He was inspired by the results of a study in the mouse hippocampus which found that GABA was controlling stem cell activity.

Working with Patton and assistant professor Dominic Didiano, Rao designed a series of experiments with zebrafish which determined that high concentrations of GABA in the retina keep the Miller glia quiescent and that they begin dedifferentiating and proliferating when GABA concentrations drop.

They tested their hypothesis in two ways: By blinding zebrafish and injecting them with drugs that stimulate GABA production and by injecting normal zebrafish with an enzyme that lowers the GABA levels in their eyes.

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Agencies
January 5,2020

Washington D.C., Jan 5: After a woman filed a lawsuit against a diet soda company, the California court has declared that the beverage does not promise to help buyers in losing weight.

The woman had gulped down the drink for over a decade but did not lose inches as a result.

The three-judge panel declared during the hearing: "The prevalent understanding of the term in (the marketplace) is that the 'diet' version of a soft drink has fewer calories than its 'regular' counterpart."

However, the members of the US 9th circuit court have felt that the consumers tend to make out something of their own that is unreasonable and eventually hamper the reputation of brands through a deceptive allegation, reports Fox News.

The response was due to a misleading case filed against Diet Dr Pepper by Shana Becerra from Santa Rosa, California. Shana claimed that she has been addictively purchasing the low-calorie beverage for the past 13 years hoping for losing some fat but failed to lose even a single inch.

The woman also stated that the attractive and fit models misled her into believing that drink will help her in perfecting her body like them.

However, the court's decision was that advertisements are for representational purposes only. "Cannot be reasonably understood to convey any specific meaning at all," as written by Judge Jay Bybee.

Shana had last week made such allegation against Diet coke as well where the court came to a similar verdict. She claimed that she had found various studies where it is evident that the artificial sweetener aspartame used in diet beverages actually boosts weight gain.

But the artificial sweetener is approved in by the concerned administrative department and thus is used in most American drinks.

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Agencies
May 6,2020

Washington D.C., May 5: Working from home has become the new normal ever since the outbreak of coronavirus and in today's time the work duties can be easily dealt with by means of mobile devices at home.

However, this easy use of technology, mobile devices for that matter, has the potential to blur the fine line between work and the other daily life routines.

But, contrary to the belief, a study at the University of Jyvaskyla reveals that the mixing of work and other daily life routines may have more benefits than previously assumed, and points to the importance of boundary-spanning communication.

A smartphone enables phone calls, email, and file transfers from the comfort of home. The study shows that there may be more effective ways to maximise the benefits of smartphone use, without diminishing employees' flexibility and the use of these technologies.

"People often forget to talk about positive effects, such as autonomy and freedom the employees gain when they have the flexibility to schedule their work," said Postdoctoral Researcher Ward van Zoonen from JYU, who with his colleagues examined the use of smartphones for work matters outside working hours.

The study paid special attention to the benefits of talking about domestic matters with the immediate supervisor outside the working hours given to an employee.

"This reduces the conflict between work and other life," van Zoonen said.

"If people in an organisation strive for more dialogue between employees' different life domains, it is possible to create a functional environment where people can talk about different matters."

The research findings show that when employees communicate across boundaries and talk at work about their life in other respects, they can receive new kinds of support and understanding from their immediate supervisor.

"This kind of communication creates a low threshold for contacting one's supervisor, which helps employees build a balance between the different domains of their lives and strengthens their organisational identification," said Professor Anu Sivunen describing the findings.

This means that tight working time restrictions to protect employees might not be beneficial after all, if they hinder reaching the positive results indicated in this research.

For the study, a survey was taken of 367 employees who were asked questions such as -- how much they talk about their work with their family, and how much they talk about their family with their immediate supervisor.

"Both supervisors and their employees answered the surveys, and the study actually focused on their mutual communication," Sivunen said.

"Usually people at workplaces are interested in how communication within the work community is succeeding. It is often forgotten how an immediate supervisor can take an employer's other life into account and thereby help the employee gain work-related benefits."

"Communication with one's immediate supervisor during flexible working hours, also on matters other than work, could ease the daily lives of many employees if they could share the possible challenges of their family life or free time with their supervisor in these settings," Sivunen added.

According to the study, such a practice could make the supervisor aware of the employee's situation as he/she works from home and the related impacts on their work performances.

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Agencies
July 7,2020

The World Health Organization (WHO) is reviewing a report that suggested its advice on the novel coronavirus needs updating after some scientists told the New York Times there was evidence the virus could be spread by tiny particles in the air.

The WHO says the Covid-19 disease spreads primarily through small droplets, which are expelled from the nose and mouth when an infected person breaths them out in coughs, sneezes, speech or laughter and quickly sink to the ground.

In an open letter to the Geneva-based agency, 239 scientists in 32 countries outlined the evidence they say shows that smaller exhaled particles can infect people who inhale them, the newspaper said on Saturday.

Because those smaller particles can linger in the air longer, the scientists - who plan to publish their findings in a scientific journal this week - are urging WHO to update its guidance, the Times said.

"We are aware of the article and are reviewing its contents with our technical experts," WHO spokesman Tarik Jasarevic said in an email reply on Monday to a Reuters request for comment.

The extent to which the coronavirus can be spread by the so-called airborne or aerosol route - as opposed to by larger droplets in coughs and sneezes - remains disputed.

Any change in the WHO's assessment of the risk of transmission could affect its current advice on keeping one-metre physical distancing. Governments, which also rely on the agency for guidance policy, may also have to adjust public health measures aimed at curbing the spread of the virus.

"Especially in the last couple of months, we have been stating several times that we consider airborne transmission as possible but certainly not supported by solid or even clear evidence," Benedetta Allegranzi, the WHO's technical lead for infection prevention and control, was quoted as saying in the New York Times.

WHO guidance to health workers, dated June 29, says that SARS-CoV-2, the virus that causes Covid-19, is primarily transmitted between people through respiratory droplets and on surfaces.

But airborne transmission via smaller particles is possible in some circumstances, such as when performing intubation and aerosol-generating procedures, it says.

Medical workers performing such procedures should wear heavy-duty N95 respiratory masks and other protective equipment in an adequately ventilated room, the WHO says.

Officials at South Korea's Centers for Disease Control said on Monday they were continuing to discuss various issues about Covid-19, including the possible airborne transmission. They said more investigations and evidence were needed.

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