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
May 20,2020

Washington D.C., May 20: While a dairy-rich diet is helpful in meeting the body's calcium requirement, outcomes of a large international study links eating at least two daily servings of dairy with lower risks of diabetes and high blood pressure.

The dairy-rich diet also proved to lower the cluster of factors that heighten cardiovascular disease risk (metabolic syndrome). The study was published online in journal BMJ Open Diabetes Research & Care.

The observed associations were strongest for full-fat dairy products, the findings indicated.

Previously published research has suggested that higher dairy intake is associated with a lower risk of diabetes, high blood pressure, and metabolic syndrome. But these studies have tended to focus on North America and Europe to the exclusion of other regions of the world.

To see whether these associations might also be found in a broader range of countries, the researchers drew on people taking part in the Prospective Urban Rural Epidemiology (PURE) study.

Participants were all aged between 35 and 70 and came from 21 countries: Argentina; Bangladesh; Brazil; Canada; Chile; China; Colombia; India; Iran; Malaysia; Palestine; Pakistan; Philippines, Poland; South Africa; Saudi Arabia; Sweden; Tanzania; Turkey; United Arab Emirates; and Zimbabwe.

Usual dietary intake over the previous 12 months was assessed by means of Food Frequency Questionnaires. Dairy products included milk, yogurt, yogurt drinks, cheese and dishes prepared with dairy products, and were classified as full or low fat (1-2 percent).

Butter and cream were assessed separately as these are not commonly eaten in some of the countries studied.

Information on personal medical history, use of prescription medicines, educational attainment, smoking and measurements of weight, height, waist circumference, blood pressure and fasting blood glucose were also collected.

Data on all five components of the metabolic syndrome were available for nearly 113,000 people: blood pressure above 130/85 mm Hg; waist circumference above 80 cm; low levels of (beneficial) high-density cholesterol (less than 1-1.3 mmol/l); blood fats (triglycerides) of more than 1.7 mmol/dl; and fasting blood glucose of 5.5 mmol/l or more.

Average daily total dairy consumption was 179 g, with full-fat accounting for around double the amount of low fat: 124.5+ vs 65 g.

Some 46, 667 people had metabolic syndrome--defined as having at least 3 of the 5 components.

Total dairy and full-fat dairy, but not low-fat dairy, was associated with a lower prevalence of most components of metabolic syndrome, with the size of the association greatest in those countries with normally low dairy intakes.

At least 2 servings a day of total dairy were associated with a 24 percent lower risk of metabolic syndrome, rising to 28 percent for full-fat dairy alone, compared with no daily dairy intake.

The health of nearly 190,000 participants was tracked for an average of nine years, during which time 13,640 people developed high blood pressure and 5351 developed diabetes.

At least 2 servings a day of total dairy was associated with a 11-12 percent lower risk of both conditions, rising to a 13-14 percent lower risk for 3 daily servings. The associations were stronger for full fat than they were for low-fat dairy.

This is an observational study, and as such can't establish the cause. Food frequency questionnaires are also subject to recall, and changes in metabolic syndrome weren't measured over time, all of which may have influenced the findings.

Nevertheless, the researchers suggest: "If our findings are confirmed in sufficiently large and long term trials, then increasing dairy consumption may represent a feasible and low-cost approach to reducing [metabolic syndrome], hypertension, diabetes, and ultimately cardiovascular disease events worldwide."

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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
June 28,2020

As the COVID-19 wave sweeps strongly across the country, including in Tamil Nadu, mental health experts say the pandemic has triggered panic attacks among those who tested positive for the virus, causing bouts of depression and even driving some to the brink of suicide.

According to experts, nervousness, fear of contamination, panic attacks, constant reassurance seeking behaviour, sleep disturbance, excessive worry, feelings of helplessness and probability of an economic slowdown are the major factors leading to depression and anxiety among the people.

Potential job losses, financial burden, uncertainty about the future and fears of running out of food and necessities add to the worries.

Online platforms too have seen a growing number of people seeking help for mental health issues, ranging from anxiety and loneliness to concerns over productivity and job loss since the outbreak of COVID-19.

Director of Institute of Mental Health here, Dr R Purna Chandrika said towards April end about 3,632 calls were received and psychiatric counselling was provided to 2,603 callers.

"We have dedicated services at our centres in the districts and the calls meant for government medical college hospitals are routed to the respective institutions," she said.

Due to heavy virus caseloads, making this city the major contributor to the state's tally, the Greater Chennai Corporation too started a free helpline to help residents cope up with stress during the pandemic.

"From the psychological perspective, we don't find a single human being who is not feeling some degree of stress or anxiety due to coronavirus. The intensity and impact varies from person to person," said Lt Col N T Rajan, director of Chennai-based Mastermind Foundation.

The organisation is involved in free counselling throughout India ever since the first case of the deadly virus was reported in the country.

The foundation's recommendation on not to deploy the vulnerable in the police force, especially those above 50 years and women personnel with children below five years for COVID-19 related duty, was accepted and implemented by the Punjab government.

Psychiatrists feel that further worsening situations could lead to severe mental health issues, even triggering suicidal tendencies.

"Further worsening depression may lead to severe mental health issues and suicidal tendencies," said Dr S Senthil Kumar, a psychiatrist.

However, not all of them require medicines, he added.

"The situation is serious. There should be counselling at three stages--on coping with the virus, how to face it if tested positive and how to face life once treated and discharged from the hospital," Rajan said.

Awareness was of paramount importance, he said and warned the pandemic could cause panic attacks while in hospital or drive them to the brink of suicide.

Tamil Nadu, one of the worst affected states with a virus count in excess of 74,000 as of Friday, has witnessed a few instances of suicides allegedly related to COVID-19.

Hari Singh, owner of popular 'Iruttu Kadai' halwa shop in Tirunelveli, allegedly died by committing suicide on Thursday after being tested positive for COVID-19. He was 80.

Earlier in May, two COVID-19 patients in their 50s allegedly committed suicide in separate instances, at the government hospitals they were admitted to for treatment.

In the city corporation limits, a three-member team comprising a psychiatrist, counsellor and a social worker work for the respective zones.

"We direct certain sections of people like those with withdrawal symptoms and people requiring pills, to visit the doctor at their corporation zonal at a specific time, for medicines," a health worker of the civic body said.

Health platform, Lybrate reported an increase of 180 per cent in online patient consultations related to mental health on its platform between March 1 and June 20 across the country.

The largest increase came from Mumbai and Delhi, followed by Pune, Ahmedabad, Chennai and Bengaluru.

The biggest jump was witnessed in the age group of 25 and 45 years.

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