Blue light from smartphones may speed blindness

Agencies
August 9,2018

Washington, Aug 9: Blue light emitted from smartphones and other digital devices can accelerate blindness by transforming vital molecules in the eye's retina into cell killers, a study has found.

Macular degeneration, an incurable eye disease that results in significant vision loss starting on average in a person's 50s or 60s, is the death of photoreceptor cells in the retina.

Those cells need molecules called retinal to sense light and trigger a cascade of signalling to the brain.

"We are being exposed to blue light continuously, and the eye's cornea and lens cannot block or reflect it," said Ajith Karunarathne, an assistant professor at University of Toledo in the US.

"It's no secret that blue light harms our vision by damaging the eye's retina. Our experiments explain how this happens, and we hope this leads to therapies that slow macular degeneration, such as a new kind of eye drop," said Karunarathne.

The study, published in the journal Scientific Reports, found that blue light exposure causes retinal to trigger reactions that generate poisonous chemical molecules in photoreceptor cells.

"It's toxic. If you shine blue light on retinal, the retinal kills photoreceptor cells as the signalling molecule on the membrane dissolves," said Kasun Ratnayake, a PhD student researcher working in Karunarathne's group.

"Photoreceptor cells do not regenerate in the eye. When they're dead, they're dead for good," said Ratnayak.

Karunarathne introduced retinal molecules to other cell types in the body, such as cancer cells, heart cells and neurons. When exposed to blue light, these cell types died as a result of the combination with retinal. Blue light alone or retinal without blue light had no effect on cells.

"No activity is sparked with green, yellow or red light. The retinal-generated toxicity by blue light is universal. It can kill any cell type," Karunarathne said.

The researcher found that a molecule called alpha tocoferol, a Vitamin E derivative and a natural antioxidant in the eye and body, stops the cells from dying.

However, as a person ages or the immune system is suppressed, people lose the ability to fight against the attack by retinal and blue light.

"If you look at the amount of light coming out of your cell phone, it's not great but it seems tolerable," Dr. in the UT Department of Chemistry and Biochemistry, said.

"Some cell phone companies are adding blue-light filters to the screens, and I think that is a good idea," said John Payton, visiting assistant professor at University of Toledo.

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'Children under the age of 5 carry higher levels of Covid-19'

Agencies
August 2,2020

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Washington, Aug 2: Children under the age of five have between 10 to 100 times greater levels of genetic material of the coronavirus in their noses compared to older children and adults, a study in JAMA Pediatrics said Thursday.

Its authors wrote this meant that young children might be important drivers of Covid-19 transmission within communities -- a suggestion at odds with the current prevailing narrative.

The paper comes as the administration of US President Donald Trump is pushing hard for schools and daycare to reopen in order to kickstart the economy.

Between March 23 and April 27, researchers carried out nasal swab tests on 145 Chicago patients with mild to moderate illness within one week of symptom onset.

The patients were divided into three groups: 46 children younger than five-years-old, 51 children aged five to 17 years, and 48 adults aged 18 to 65 years.

The team, led by Dr Taylor Heald-Sargent of the Ann & Robert H. Lurie Children's Hospital, observed, "a 10-fold to 100-fold greater amount of SARS-CoV-2 in the upper respiratory tract of young children."

15 countries with the highest number of cases, deaths due to the Covid-19 pandemic

The authors added that a recent lab study had demonstrated that the more viral genetic material was present, the more infectious virus could be grown.

It has also previously been shown that children with high viral loads of the respiratory syncytial virus (RSV) are more likely to spread the disease.

"Thus, young children can potentially be important drivers of SARS-CoV-2 spread in the general population," the authors wrote.

"Behavioral habits of young children and close quarters in school and daycare settings raise concern for SARS-CoV-2 amplification in this population as public health restrictions are eased," they concluded.

The new findings are at odds with the current view among health authorities that young children -- who, it has been well established, are far less likely to fall seriously ill from the virus -- don't spread it much to others either.

However, there has been fairly little research on the topic so far.

One recent study in South Korea found children aged 10 to 19 transmitted Covid-19 within households as much as adults, but children under nine transmitted the virus at lower rates.

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National Bone and Joint Day | Bone and joint problems in obese

Dr G K Sudhakar Reddy
August 4,2020

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Being overweight or obese is now recognised as a serious cause of ill health and disability. There is a significant positive association between orthopaedic disorders and the level of obesity causing pain, deformity and difficulty in walking.

Excess body weight accumulation increases pressure on joints, particularly the hips, knees and ankles.

Here are a few type of  arthritis:

Osteoarthritis

It is a condition of damage/ wear and tear of the joint lining or cartilage. Obesity triggers this by loading excessive weight on the weight bearing joints like the knee and the hip. 

Knee Osteoarthritis

This is the most common arthritis especially in the Indian subcontinent.

While walking, an individual exerts 3 to 6 times pressure that of the body weight on the weight-bearing knee joint, which means in an obese with excess body weight, larger forces are exerted, which lead to higher risk of deterioration of cartilage.

In addition, there are excessive fat tissues that produce hormones and other factors that affect the joint cartilage metabolism and cause inflammation of the joints giving rise to joint pathology.  Leptin is one of the hormones causing knee osteoarthritis. 

Hip osteoarthritis

The force exerted across the hip is 3 times that of body weight. Hip osteoarthritis is caused by factors such as joint injury, increasing age and being overweight.    

Hand osteoarthritis

The observation that obese individual has a higher risk in having hand osteoarthritis has led to a hypothesis that the metabolic effect produced by fat tissue is the underlying factor. 

Osteoporosis

It is a progressive bone condition of decrease in bone mass and density (Bone Mineral Density or BMD) which can lead to an increased risk of fracture. Recent research suggests that obesity may accelerate bone loss. It is the amount of muscle mass which is seen in an active person, which accounts for bone strengthening effects and not due to the fat seen in a heavy person.

Low back pain

Low back pain from degenerative disc disease of the lumbar spine is one of the most disabling conditions in the community and overweight and obesity have the strongest association with seeking care for low back pain.

Managing Hip and Knee Osteoarthritis

Life style changes

If one is overweight, try to lose weight by doing more physical activity and eating a healthier diet. Regular exercise keeps you active and mobile and builds up muscle, thereby strengthening the joints and can improve symptoms. 

Pain Killers

Painkillers help with pain and stiffness for short term. They don’t affect the arthritis itself and won’t repair the damage to your joint. Creams and gels can be applied directly onto painful joints.

Nutritional Supplements

Glucosamine and chondroitin are nutritional supplements. Animal studies have found that glucosamine can both delay the breakdown of and repair damaged cartilage. However, there is insufficient evidence to support the use of glucosamine in humans and one can expect only a mild-to-moderate reduction in pain

Joint injections

If pain from osteoarthritis is severe joint steroid injections are injected into the joints that can reduces swelling and pain. The injections can start working within a day or so and may improve pain for several weeks or months. 

Hyaluronic acid injections, which help to lubricate your knee joint also give short term relief. In early stages. Stem cell treatment or cartilage regeneration procedures are being tried in young people with small defects, however it is still experimental and lacks long term evidence.

Surgery

May be recommended if you have severe pain or mobility problems.

Arthroscopy

If one has frequent painful locking/stiffening episodes especially in the knee joint, an operation to wash out loose fragments of bone and other tissue as joint can be performed by a minimally invasive key hole procedure called Arthroscopy.

Arthrodesis

If hip or knee replacement is not suitable, especially in young people who do heavy manual work, one can consider an operation known as an arthrodesis, which fuses your joint in a permanent position. This means that your joint will be stronger and much less painful, although you will no longer be able to move it.

Osteotomy

In young, active people in whom a knee joint replacement would fail due to excessive use one can consider an operation called an osteotomy. This involves adding or removing a small section of bone either above or below your knee joint.  This helps realign your knee so your weight is no longer focused on the damaged part of your knee. An osteotomy can relieve your symptoms of osteoarthritis, although you may still need knee replacement surgery eventually as you grow old

Joint replacement surgery

Joint replacement therapy is most commonly carried out to replace hip and knee joints. It involves replacing a damaged, worn or diseased joint with an artificial joint made of special plastics and metal.

For most people, a replacement hip or knee will last for at least 20 years, especially if it is cared for properly and not put under too much strain.

Dr G K Sudhakar Reddy is a Sr Consultant Orthopaedic Surgeon at Citizens Speciality Hospitals, Hyderabad

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Is coronavirus spreading through air?

Agencies
July 30,2020

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New York, Jul 30: Can the coronavirus spread through the air? Yes, it's possible.

The World Health Organisation recently acknowledged the possibility that Covid-19 might be spread in the air under certain conditions.

Recent Covid-19 outbreaks in crowded indoor settings — restaurants, nightclubs and choir practices — suggest the virus can hang around in the air long enough to potentially infect others if social distancing measures are not strictly enforced.

Experts say the lack of ventilation in these situations is thought to have contributed to spread, and might have allowed the virus to linger in the air longer than normal.

In a report published in May, researchers found that talking produced respiratory droplets that could remain in the air in a closed environment for about eight to 14 minutes.

The WHO says those most at risk from airborne spread are doctors and nurses who perform specialized procedures such as inserting a breathing tube or putting patients on a ventilator.

Medical authorities recommend the use of protective masks and other equipment when doing such procedures.

Scientists maintain it's far less risky to be outside than indoors because virus droplets disperse in the fresh air, reducing the chances of Covid-19 transmission.

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