Monday, September 30, 2019

Personalized diets may be the future of nutrition. But the science isn’t all there yet

Microbiologist Lora Hooper wishes she had a good answer when her mother asks, “What should I eat?”

Hooper could rely on a familiar refrain. Eat plenty of fruits, vegetables and whole grains, and limit meat and fat intake. Try to eat foods low on the glycemic index, a measure of how high a particular food is likely to send a person’s blood sugar after eating it.

Nutrition recommendations have focused on properties of food, debating whether focusing on calorie counts, carbohydrates, fats or proteins might be more important. But more studies are showing that people’s bodies can react very differently to the same foods, and standardized nutrition advice doesn’t fit everybody. Even identical twins can have varying responses to identical foods, new research finds, suggesting that the variety can’t be explained by genes alone.

With genetics being put on the back burner, researchers are searching for other explanations for why a diet one person swears by may cause another to gain weight. One big player may be the friendly bacteria and other microbes in people’s guts.

“Your microbiota really determines how many calories you take up from your food,” says Hooper, of the University of Texas Southwestern Medical Center in Dallas. Without a better understanding of how gut microbes will react, she says, “I don’t think I can read the number of calories in my food off a box.”

So instead of focusing on the food, people like Hooper’s mother may have to look within to their own gut microbes or other personal qualities to find the diet that works best for them, an approach known as personalized nutrition. But tailoring food regimens to individuals isn’t likely be a piece of cake, either.

Finding the perfect diet is more important than ever as epidemics of obesity and type 2 diabetes sweep the globe. Worldwide, more than 1.9 billion adults and 380 million children and adolescents — about a quarter of the world’s population — were overweight in 2016, with 650 million of those people obese, according to the World Health Organization. An estimated 422 million people had diabetes in 2014, and rates of the disease have continued to grow.  

diet guidelines example
Dietary guidelines may not be tailored enough to individual metabolism, some scientists say.USDA’S CENTER FOR NUTRITION POLICY AND PROMOTION

Follow the guidelines?

Strive as they might to follow healthy diets, people may be thwarted by what they don’t know about their own response to food. Geneticist Tim Spector thought the small sandwich and glass of orange juice he typically bought in the hospital cafeteria was a healthy option. Then he discovered that both bread and orange juice send his blood sugar levels soaring into the diabetic range.

And “I get much worse sugar response to a banana than to an equivalent size of an apple,” says Spector, of King’s College London. He now chooses apples and pears over bananas. “It’s no hardship,” he says, “because I like both.”

Standard advice to eat fruits and vegetables, however, would never clue Spector in to which choice is truly healthier for him. He is not alone. Previous studies have determined that some people’s blood sugar may shoot up more after eating a banana than a cookie, while another person may have the opposite reaction (SN: 11/19/15).

Spector and others have confirmed the varied landscape of blood sugar peaks and valleys that people achieve after eating standardized foods full of carbohydrates. In the short term, high blood sugar spikes might produce headaches and fatigue. Over the long haul, high blood sugar — the hallmark of diabetes — can lead to damage of blood vessels, nerves and organs.

It’s not just carbohydrates that produce a variety of responses. People respond differently to dietary fats, too, Spector and colleagues discovered in a new study tracking foods’ effects on more than 1,000 people, including hundreds of identical twins. Spector presented the preliminary, unpublished results June 11 in Baltimore at the American Society of Nutrition’s annual meeting.

Researchers in the PREDICT I study gave volunteers standardized foods and tracked participants’ blood levels of the sugar glucose, insulin and dietary fats called triglycerides. How quickly people cleared the fats from their blood after a meal couldn’t be predicted by knowing what happened to their blood sugar or insulin levels after a meal, the team found.

Different spikes

In the PREDICT study, scientists confirmed that 1,001 people’s blood glucose responses (individual response, gray lines) to a standardized food could vary tremendously from the mean (average) or median of the group as a whole, hinting that each individual may need personalized diets to limit blood sugar spikes. 
How people’s blood glucose levels spike differently after eating a muffin

Blood glucose graph
But perhaps the biggest surprise from the study was that even identical twins process food differently.

Follow the genes?

Identical twins Julie Hodgson and Diane Portlock look like each other. Except Portlock, a firefighter in Worcester, England, weighs about 50 pounds more than her twin. The 46-year-old sisters always put their weight difference down to lifestyle. After all, Hodgson, of Ash Vale, England, is a competitive rower in the British Army who took a gold medal in the United Kingdom Invictus Games trials in July. She exercises more than her sister does and tends to go for salads, while Portlock admits “I like cheese. I like bread. I like a glass of wine.”

But now the sisters have discovered that their bodies handle food differently, too. In an extension of Spector’s study, Hodgson’s blood sugar after a meal would usually rise gradually then taper off “in a nice little rounded arch,” her sister says. But Portlock’s glucose levels spiked and quickly fell and then rose again in what she calls “a double dip.”

“My insulin response is really quite efficient,” Hodgson says. Her body handles carbohydrates well, and eating more carbs fills her up and gives her more energy to train. But not all carbs work for her. Spaghetti Bolognese is Hodgson’s worst food for triggering a glucose spike, even though pasta is considered a low glycemic index food. Now, she avoids pasta and eats other carbs, including mashed potatoes, her twin’s nemesis for causing blood sugar spikes. 

Julie Hodgson and Diane Portlock
Julie Hodgson (left) and Diane Portlock (right) are identical twins who recently discovered that they have different reactions to certain foods from each other.JULIE HODGSON, DIANE PORTLOCK

“Although our DNA and our genetics are the same, the study has proven that, in fact, we’re very individual as well,” Portlock says.

Genes explain less than half of an individual’s varying responses to food, Spector and colleagues calculate. That’s bad news for people who shell out money for consumer DNA testing companies to tell them what to eat (SN: 5/22/18), Spector says. “Genes are going to be limited when it comes to predicting food responses.”

What’s more, the macronutrient content of the food — the amount of carbs, fat and protein — accounted for only 16 to 32 percent of varying responses, the researchers found. The rest is still a mystery, and could relate to a litany of causes. Medications, the amount and quality of sleep people got, how much they exercised, when people ate and what order they ate foods in, their overall health and biological rhythms as well as the microbes living in the volunteers’ guts might all influence their reactions, Spector says. His team is recruiting volunteers for an even larger study aimed at better understanding the factors that influence metabolism.

Follow the microbes?

Gut microbes are probably the most important factor, says immunologist and microbiome researcher Eran Elinav of the Weizmann Institute of Science in Rehovot, Israel. Past research has shown that microbes determine how much fiber and other complex carbohydrates get digested. Bacteria in the small intestines may influence how much fat people absorb from their food, a study in mice suggests (SN: 7/25/19).

Elinav, Weizmann colleague Eran Segal and other collaborators have found that gut microbes play a big role in controlling how much a person’s blood sugar will spike after eating white or sourdough bread (SN: 6/6/17) or a wide variety of other foods.

The researchers have cataloged hundreds of gut microbiomes — the collection of genes in bacteria, archaea, fungi and other microbes that live in the intestines — responding to thousands of meals. By deeply analyzing, or sequencing, the genes of microbes in a person’s stool samples, and comparing the results with those from people previously studied, Elinav says he can tell what will happen to someone’s blood sugar after eating a specific food. Elinav and Segal are scientific consultants to a company called DayTwo, in Adanim, Israel, that’s based on the researchers’ work.

In February, scientists at DayTwo and the Mayo Clinic reported in JAMA Network Open that they had more accurately predicted volunteers’ glycemic responses to eating a bagel and cream cheese when the team based the prediction on each volunteer’s microbiome and previous response to the meal than when predicting blood sugars based on counting carbohydrates.

But here’s where things get sticky, because what people eat also affects the microbes in the gut in very personal ways.

“What you eat does determine which microorganisms are in your gut. There’s no question about that,” Hooper says. But exactly what about that food influences microbiome changes is a mystery.

It at least seems that microbes don’t count carbs, nutrition scientist Abigail Johnson of the University of Minnesota in Minneapolis and colleagues reported in the June 12 Cell Host & Microbe. Johnson’s colleagues — 34 students enrolled in a citizen science class at the university — were also the study’s research subjects. The students kept detailed food records and collected fecal samples every day for two and half weeks. The team cataloged the abundance of types of bacteria in each person’s stool samples and tried to determine which properties of food determined how the microbe mixes would change.   

“We couldn’t look at nutrients and find relationships with nutrients and the microbiome,” Johnson says. But looking at foods eaten over the previous days predicted how the microbiome would change. For instance, knowing that a food was spaghetti with tomato sauce and meat told the researchers more about how the microbiome would change than knowing the carbohydrate, fat and protein content of the food did. Microbes may be more concerned with trace nutrients or chemical components of food that aren’t included on labels, Johnson says.

She thinks that the microbiome, at least the microbes in feces, probably aren’t the major driver of how a person responds to food. “It’s a player certainly,” but not the whole story, Johnson says.

To personalize or not to personalize

Other researchers caution against being too quick to discount the properties of the foods themselves. “The glycemic index is still an important worm in this can of worms,” says Jennie Brand-Miller, a nutrition scientist at the University of Sydney.

That’s in part because people’s variability to different foods is already baked into the glycemic index, Brand-Miller says. She likens the glycemic index to the tides. Although tides may vary from bay to bay, and season to season, “On any given day high tide will be higher than low tide.” Similarly, she says, “on any given day we have a 99 percent chance that high GI food will give a higher response than a low GI food.”

For most people, she argues, following standard nutritional advice will help them get and stay healthy.

But, Elinav says, nutritionists tend to place the blame for the failure of nutritional guidelines to stem the tide of obesity and diabetes on people not following the guidelines. “Rather than blaming the public for not following these recommendations, which often change, maybe the guidelines themselves are not sufficient or not evidence-based enough,” he says.

Personalizing nutrition may do better than the one-size-fits-all guidelines for controlling blood sugar, Elinav says. He and colleagues are pitting the conventional approach and their microbiome approach against each other in a head-to-head trial. The results may be known later this year.

Still, there’s probably no harm in eating within the standard guidelines. “I don’t think we’re going to get 20 years down this line of personalized nutrition research and find out fruits and vegetables are bad,” Johnson says. But in the future, people may be able to optimize those recommendations for themselves by adding or avoiding certain foods.

Until then, when Hooper’s mother asks what to eat, she can only reply, “Mom, I don’t know.” 

Tina Hesman Saey

Tina Hesman Saey is the senior staff writer and reports on molecular biology. She has a Ph.D. in molecular genetics from Washington University in St. Louis and a master’s degree in science journalism from Boston University.

Saturday, September 21, 2019

New vaccine skin patch could do away with needles

Scientists have been studying needle-free vaccine approaches for nearly 2 decades.

Scientists are hopeful that a new type of skin patch could replace needles as a method of flu vaccination. When they tested the skin patch on mice, it elicited an appropriate immune response without side effects. 

The Centers for Disease Control and Prevention (CDC) estimate that the flu caused 48.8 million illnesses, 959,000 hospitalizations, and 79,400 deaths in the United States during the 2017–2018 season. That season had an unusually high flu burden that was severe across all age groups.

Eczema inspires a new method of delivery.

Prof. Miller and his colleagues believe that the new flu vaccine skin patch solves many of the problems that other developers have faced. In their study paper, the authors explain how previous attempts to deliver a flu vaccine with skin patches have used techniques such as microneedles and electroporation. However, while enjoying early success, these methods have proved difficult to "implement on a large scale for mass vaccination strategies." In contrast to these techniques, the new patch uses a novel approach that came to researchers when they investigated the biology of atopic dermatitis or eczema. In people with eczema, the skin barrier that normally prevents toxins and allergens from entering the body stops working properly and becomes permeable, or leaky. The protein claudin-1 is essential for preventing leakiness of the skin barrier. People with eczema have low levels of claudin-1 compared with those without the skin condition. In previous work, the researchers had shown that reducing claudin-1 in skin cells of healthy people increased leakiness.
This result made them wonder whether they could use a similar method to get a flu vaccine virus into the body through the skin. The challenge would be to induce leakiness for a length of time that lets in the vaccine virus but does not allow other materials to enter.

Skin patch boosted immunity.

Through a series of experiments with human skin cells, the team identified a peptide, or small protein, that can disrupt the skin barrier without causing toxic side effects. The peptide works by binding to and blocking claudin-1. The researchers then created a skin patch containing the peptide and a recombinant flu vaccine and tested it in two ways on mice. In the first test, they applied the skin patch and then gave the mice a flu vaccine by injection. Their aim was to prime the immune system with the patch and then boost immunity with the flu shot. In the second test, the team gave the mice the flu shot first and then applied the skin patch. Here, the aim was the other way around: prime the immune system with the flu shot and boost it with the skin patch. In both tests, in which the mice wore the patch on their shaved back for 18–36 hours, the patch opened the skin barrier. The researchers confirmed this by monitoring the water that the mice lost through their skin.

When they applied the patch, the researchers saw the mouse skin become permeable. However, as soon as they removed the patch, they noted that the skin began to close again, meaning that it was back to normal within 24 hours. The immune response to the patch in the first test was not significant. However, there was a robust immune response to the skin patch in the second test.
Given that "[h]umans are exposed to influenza as young as 6 months of age" and that as a consequence, most people's immune systems are already primed to the virus, the second test best mimics a real-world scenario. Therefore, these findings would suggest that the skin patch could serve as a delivery mechanism for the regular seasonal flu vaccine. Another notable result was that the researchers saw no side effects. They monitored the mice for 3 months and observed no physical changes in their skin, such as those that might arise from infections.

Cheap and safe way to deliver vaccines.

It will be some time before the skin patch is ready for human trials. The researchers need to run more animal studies to find out, for instance, how long the patch should remain on the skin for optimum results. The researchers believe that should the skin patch pass flu trials in humans, the technique could work for other vaccines that currently require needles. While they are effective, needle-based vaccines can cause people distress, and they require medical staff to deliver them. In addition, needles are biohazardous waste and require careful handling. These barriers are particularly acute in less developed countries, which also happen to have the greatest need for vaccines. Delivery by means of a skin patch could be a quick and cheap way to vaccinate large numbers of people. "If you want to vaccinate a village in Africa, you don't want to do it with needles," Prof. Miller explains.



Monday, September 16, 2019

Vaginal fluid transplants to be available in US

BV bacteria covering cells
US doctors are hoping to start offering women vaginal fluid transplants and have set up a programme to screen potential donors.
They believe some women could benefit from a dose of healthy vaginal microbes to protect against an infection called bacterial vaginosis (BV).
The Johns Hopkins University team say they were inspired by the success of faecal or poo transplants.
Although antibiotics can treat BV, it often comes back.

What is BV?

BV is not a sexually transmitted disease, despite being an infection.
It's quite common and women who have it may notice that they have an unusual discharge that has a strong fishy smell.
The condition is not usually serious, but should be treated because having BV makes women more vulnerable to catching sexually transmitted infections and getting urinary infections.
If the woman is pregnant, it increases the risk of her having the baby early.

Why might donor vaginal fluid help?

BV can happen when there is a change in the natural balance of bacteria in the vagina.
The vagina, like the gut, is home to lots of different microorganisms.
Our diets, lifestyles and some types of medication that we may take can upset this finely balanced ecosystem.
While there has been a large amount of work into the gut microbiome, less is known about the vagina.
Experts know healthy microorganisms in the vagina prefer an acidic environment, and when the pH becomes too alkaline other bacteria - including those that cause BV - can thrive.
A number of factors can raise vaginal pH and make BV more likely, including having sex (semen and saliva are slightly alkaline) and using douches or vaginal washes, as well as hormonal changes at particular times of the month during a woman's menstrual cycle.

What would the transplant involve?

The researchers have been looking at what makes a fit, safe donation in preparation for starting to offer women with BV the transplants - which they hope to do soon now that they have regulatory approval from the Food and Drugs Administration.
They screened a small number of volunteers and have reported their findings in the journal Frontiers in Cellular and Infection Microbiology.
Based on the 20 women they have tested, the researchers say they have gained some insights into what might make an "ideal" donor.
Vaginal fluid samples dominated by a bacterium called Lactobacillus crispatus tended to have higher protective lactic acid content and a lower pH which might be beneficial, they say.
As a precaution, donors would be asked to abstain from sex for at least 30 days before giving a sample and would be screened for any infections, including HIV, to prevent them being passed on to any recipient, they add.
One of the researchers, Dr Laura Ensign, said: "The donation is a self collection, which we know people tend to prefer."
The woman inserts and then removes a flexible plastic disc - similar to a menstrual cup or a contraceptive diaphragm - to collect the sample.
"It's quick and easy and one sample collected like that would be enough material to make one dose for transfer," she said.
It would be drawn up into an applicator for the recipient to insert in a similar way to a tampon.
Dr Ensign said: "If we can get funding, we could start right away. Some of the donors that we studied said they would want to take part.
"We'd plan to give transplants to 40 recipients to begin with. Some would receive the real thing and others a placebo. All of them would get antibiotics for their BV too though."

Saturday, September 14, 2019

Ebola case in Tanzania!!!!! ministry warned

Image result for ebola in tanzania
Few days back there was a rumor circulating on social media abut the presence of two Ebola cases in Tanzania mainland,although the Tanzanian government has rejected the rumor via it's ministry of health minister DR.Ummy Mwalimu. In addition to that the minister has said that only the ministry of health can declare state of emergency in case of eruption of diseases including Ebola disease.
The rumor that has been circulating on social media was initiated by the case of a Dr from Bugando who was upgrading her masters education from Uganda (Makerere university) fell sick soon after reaching Tanzania. Her diagnosis wasn't clear hence results into a mind conflict and fear among health workers and surrounding society in general.
Her case has brought tension from World Health organisation and United States of America where by together they have sent a team of specialist on identifying the disease pathogen. 
Laboratory insider will kee you informed,. dont forget to write a comment on what do you think about that case

Friday, September 13, 2019

Ghana Begins Emergency Polio Vaccination.

The Director-General of the Ghana Health Service, Anthony Nsiah-Asare, vaccinating the first child in Greater Accra to kickstart the response vaccination against polio. The Ghana Health Service (GHS) has begun a two phased emergency polio immunization exercise in the Greater Accra and the Northern Regions.The exercise which follows recent confirmations of polio cases in a two year old girl in the Chereponi district of the northern region and at Agbogbloshie, forms part of response activities to curb the further spread of the viral disease. It has been over 10 years since Ghana last recorded a polio case.
Director-General of the GHS, Dr. Anthony Nsiah Asare, speaking at the launch of the campaign at Agbogbloshie Park in Accra, said the exercise in Accra area will last till September 14, 2019. He said the four day exercise will see teams of health workers and volunteers moving from house to house, schools, markets, lorry stations, churches, mosques to vaccinate eligible children (under five) adding that there will be no fixed posts at health facilities and other designated areas. He said for the northern part of the country with the first phase is expected to commence from 25th to 28th September 2019 in all districts in the Northern, North East, Savanna, Upper East and Greater Accra regions. "Round two scheduled for 16-19 October this October this year will cover all districts in Northern, North East, Savanna and Upper East Regions," he said.

"We have teams of health workers and volunteers who will move from house to house, school to school, market to market, lorry station to lorry station, churches and mosques to vaccinate all eligible children under the ages of five years," he announced. Dr. Nsiah Asare therefore encouraged all parents and guardians to take their children born between 2016 and 2018 to health centers for vaccination. World Health Organization country representative, Dr. Owen Kaluwa said the vaccination presents an opportunity for children to be protected against polio and assured the support of the World Health Organization and other partners of the Global Polio Eradication Initiative (GPEI). "We are calling for the full support of all sectors, especially the media to create awareness and generate demand for the vaccination campaign," he said.

Thursday, September 12, 2019

Chinese Scientists Try to Cure One Man's HIV With Crispr

Image result for crispr technology
Imagine you’re 27 years old and you start feeling ill. Ill enough that you go to the hospital, and after much poking and prodding and waiting for lab results you learn you’re HIV positive. Two weeks later you find out that’s not even the worst of it. You’ve got leukemia too.

Under any circumstances it would be a lot to take in. Especially in China, where HIV/AIDS is highly stigmatized. But for one young man living there, who this happened to in the late spring of 2016, there was one small but significant silver lining to this double whammy of a diagnosis. He would be eligible to participate in the first-ever clinical trial to assess the safety of trying to cure both the cancer and the infection in a single procedure using the gene-editing tool called Crispr.
In July of 2017, doctors in Beijing blasted the patient with chemicals and radiation to wipe out his bone marrow, making space for millions of stem cells they then pumped into his body through an IV. These new stem cells, donated by a healthy fellow countryman, would replace the patient’s unhealthy ones, hopefully resolving his cancer. But unlike any other routine bone marrow transplant, this time researchers edited those stem cells with Crispr to cripple a gene called CCR5, without which HIV can’t infiltrate immune cells.

Now, more than two years later, the patient is in good health, his cancer in full remission, as researchers report today in the New England Journal of Medicine. The edited stem cells survived and are still keeping his body supplied with all the necessary blood and immune cells, and a small percentage of them continue to carry the protective CCR5 mutation. Not enough to have cured him of HIV, though—he remains infected and on antiretroviral drugs to keep the virus in check. Still, experts say the new case study shows this use of Crispr appears to be safe in humans and moves the field one step closer toward creating drug-free HIV treatments.
“The safety profile appears to be acceptable,” pioneering cancer researcher Carl June wrote in an accompanying editorial, noting that the editing appeared to be precise, and that the engineered stem cells didn’t provoke an immune response in the patient. June did offer a caveat that the study’s single patient offered only limited data to draw on.

This is the first time an HIV-positive patient has been treated with Crispr-edited cells. But scientists have been trying to find ways to genetically disable CCR5 for more than a decade now. It all started in 2007, when a German doctor took a 41-year-old man with HIV/AIDS and leukemia off of his antiretroviral drugs and hooked a thin tube up to a vein in his chest. Through it, the so-called Berlin Patient received blood cells from a bone marrow donor who had a naturally occurring mutation called CCR5 Δ32. He was missing a chunk of DNA that ultimately allows an HIV virus to enter immune cells. The patient survived his cancer and became the first (though no longer the only) person considered to be fully cured of HIV/AIDS.What he found more striking was how quickly the science has moved from the first reports of using Crispr to treat HIV infection in mice to trying it in humans: only two years. At the University of Pennsylvania, June has led work in a groundbreaking cancer treatment called CAR-T, which involves genetically reprogramming immune cells into a clone army of tumor-targeting assassins. But it took him five years to go from studies in animals to trials involving humans. In this case, China’s more permissive biomedical research regulations might have expedited the work, or it could be that genetic engineering is lending new momentum to the race for an HIV/AIDS cure, he wrote. “In any case, the genie is out of the bottle with genome editing.”
Until that moment, scientists had only hoped to control the insidious disease, through drugs like PrEP that cut down on transmission or antiretroviral treatments that prop up patients’ immune systems. The Berlin Patient made them believe total virus annihilation was, in fact, possible.

His story galvanized labs and companies across the world to do it using genetic engineering. In 2009, California-based Sangamo Therapeutics launched the first human trials of gene-editing to treat HIV, using an older technology called zinc-finger nucleases. Those trials, which edit a person’s T cells, have produced some limited successes.
A better approach, many contend, is to instead edit the cells that make T cells (and all the other blood and immune cells) deep inside a person’s bones. Known as hematopoietic stem cells, they tend to be more resistant to editing, and require more risk and discomfort to deliver. But if you succeed, you can provide a patient with a lifetime supply of HIV-immune blood and immune cells. That’s what Crispr seems to offer.
The Chinese research team that conducted the latest study had previously transplanted Crispr-edited CCR5 mutant human cells into mice, making them resistant to HIV infection. In the spring of 2017 they registered a small human trial, to be conducted at the 307 Hospital of the People’s Liberation Army in Beijing. So far, the researchers have only enrolled and treated the single patient, according to Hongkui Deng, director of Peking University’s Stem Cell Research Center and one of the study’s coauthors. But Deng expects the trial to expand once they improve the efficiency of their technique.
To edit the donor stem cells, Deng’s team put them into a machine that applies a mild electrical shock. This allows the Crispr components—a DNA-chopping enzyme and GPS guides that tell it where to cut—to slip through the cell membrane and get to work. This approach minimizes potential mistakes, known as off-target effects, because Crispr is only in the cells for a short period of time, meaning they aren’t as likely to go rogue and break DNA they’re not supposed to. But it also means not all the cells get edited.
In an ideal world, both copies of the CCR5 gene would get snipped in all of the 163 million or so stem cells they isolated from the donor’s bone marrow. That would replicate what the Berlin Patient received from his donor. What the researchers got instead was much lower. After transplantation, only between 5.2 and 8.3 percent of the patient’s bone marrow cells carried at least one copy of the CCR5 edit. (The study authors didn’t report how many cells had both copies versus one copy edited.)
That number stayed more or less stable over the 19 months that researchers have so far tracked the patient. But the more telling question is whether T cells in the patient’s blood also retain the edit. In the specific kind of T cells that HIV uses to infiltrate the immune system, the broken version of CCR5 was present in only about 2 percent of them.
“That leaves a lot of room for improvement,” says Paula Cannon, a molecular microbiologist who studies HIV and gene-editing at the University of Southern California’s Keck School of Medicine. “At those levels, the cells would not be expected to have much of an effect against the virus.”
Another clinical trial, run by the City of Hope in Los Angeles, is investigating using zinc-finger nucleases to edit the hematopoietic stem cells of HIV-positive people, with a less aggressive bone-marrow-clearing-out step, what you might call “chemo-lite.” So far six patients have been treated, and again, after 500 days only about 2 to 4 percent of cells carried the mutation, according to data presented at an HIV/AIDS conference last month in Seattle.
“Ultimately, it comes down to the editing efficiency. That’s the biggest challenge right now,” says Rowena Johnston, vice president and director of research for amfAR, the Foundation for AIDS Research. Since 2010, the organization has awarded nearly $65 million to researchers working on HIV/AIDS cure strategies, including gene editing. “Crispr is certainly looking like the future right now, so I’m very interested these researchers decided to go in this direction.”
China has been pushing the boundaries of Crispr in humans since the tool arrived in bioengineers’ toolboxes. Last year, a scientist named Jiankui He scandalized the scientific world by using Crispr to edit CCR5 in human embryos, in an attempt to make children immune to HIV. The experiments crossed a plethora of ethical lines, in addition to not working that well. In response to the global outcry, China proposed new, stricter, regulations on gene-editing in humans.
Deng wouldn’t say whether the incident has made his own work more difficult, only that he has to be extra careful in how he explains it to the public. “Specifically, that in our study, gene-editing was applied to adult cells,” he wrote. Importantly, that means the CCR5 gene will remain unaltered in non-blood cell tissues. Studies have found that people lacking a functional CCR5 gene in all their cells are more susceptible to influenza and West Nile virus, and might even experience shortened lifespans.

Wednesday, September 11, 2019

WHO Director-General urges world leaders to protect health from climate change

Image result for environmental pollution
Climate change is one of the defining issues of our time. It is also one of the world’s most urgent health threats.
In less than two weeks’ time, I will join the UN Secretary-General and other world leaders at the Climate Action Summit at the United Nations General Assembly. This landmark summit will showcase the concrete commitments governments are making to address climate change and to secure and improve the health and well-being of their citizens. 
Two of those commitments have been developed by the World Health Organization and its partners. The first is a pledge to ensure that air meets WHO safety standards by 2030 at the latest, and to align climate change and air pollution policies. Many of the same practices that lead to climate change also result in deadly air pollution.  
The second is to provide financial resources to protect people from the detrimental health impacts of climate change. Today, less than 0.5% of international finance for climate change is allocated to health, and the most vulnerable countries, particularly small island developing states, receive only a fraction of that. Countries are being asked to allocate more to protect people against the ravages of the climate crisis.
Twelve days remain for leaders to sign up to those commitments: I urge those who have not yet made their commitments to join those who have pledged action to protect people from the devastating heatwaves, floods and cyclones linked with climate change, and to reduce the risk of malnutrition, malaria, diarrhoea, and heat stress.
The Climate Action Summit takes place on the same day as the UN High-Level Meeting on Universal Health Coverage. It is significant that these events will run in parallel. Taking steps to address and mitigate the impacts of climate change, and to ensure that everyone can access the health services they need, when and where they need them, are two of the top priorities in global public health.
Only when countries can provide health services to all, including those in greatest jeopardy from climate change, will we achieve our goals of promoting health, keeping the world safe, and protecting the vulnerable.

Sunday, September 1, 2019

Darkroom Printing guide (instruments,steps,functions)

Related image
The printing process isn’t as difficult as you might imagine and a makeshift darkroom can be set up in a bedroom, at one end of the garage, in a cellar, in a shed or even under the stairs. All that is needed is an enlarger, three trays, a power socket and a red light. The stop and fix you used to process your film can be used for printing, but a different developer is needed for the paper.
The developer can be any standard paper developer, which might come as a powder or a liquid concentrate that is mixed to the correct strength before use. Many manufacturers offer darkroom paper, but the brand I recommend you buy first is Ilford Multigrade RC (resin-coated) paper, with either a glossy or pearl surface.
The hardware for printing is easy to acquire. Second-hand darkroom gear is ridiculously cheap and sometimes even available for free. Ask at your local camera club if anyone has any old equipment looking for a home. Remember that you will need plastic trays for the chemicals, and flasks/measuring jugs to mix up solutions. You will also need a set of Multigrade filters for altering contrast, which are easily found online.

Guide to Darkroom Printing: Equipment Needed

  • Enlarger (with 50mm lens if printing 35mm film)
  • Red/orange safe light
  • 3 trays
  • Masking frame
  • 2x plastic tongs/tweezers
  • Multigrade filters (8.9cm size)
  • Multigrade paper (RC type)
  • Multigrade paper developer, stop bath and fix (check dilutions before use)
  • Plastic bottles to store mixed-up chemicals
  • Optional: electronic timer, focus finder

Making a Print: Getting Started

Once you have the equipment and you are satisfied that the wiring is safe, set up an area with the enlarger and enough space for three 10 x 8in trays (roughly 1 metre x 40cm. You should have the developer nearest to the enlarger, then the stop bath and then the fix. Beyond that, you could have a big bucket of water to put your prints in to be washed after the printing session.
Before you open your box of paper, remember that it is sensitive to light and will be ruined if there is any stray light. You can work with an orange or red light, but I would suggest turning this on after you have checked the room is totally dark. If you leave your printing until the evening, you will probably be able to cover the windows and cracks of light with a couple of layers of black bin-liner plastic, stuck up with masking tape. Once you have all the lights out, if you can still see across the room there is too much light. Small amounts of stray light can make a difference over a period of time. Cover any stray light from digital clocks, LEDs and electrical equipment, and keep your phone in your pocket.
You will need a power supply for your enlarger and safe light, although a battery-powered red bicycle light can be used at a pinch, so long as it is well away from the paper. Make sure the surface for the enlarger and trays is steady. It’s no use balancing everything on boxes. A wobbly enlarger will give you blurry prints and you don’t want spillages in the dark.
I hope you give it a go, as having actual prints that you created yourself from your own negatives is very rewarding.

Step by Step Guide to Darkroom Printing

1. Using the enlarger

Once the chemicals have been measured out, place the negative in the enlarger carrier with the shiny side upwards and the numbers away from you. Set the enlarger at the correct height to give a projected image big enough for the chosen print size. Each time you alter the height, refocus the image.

2. Positioning

Turn on the enlarger and alter the aperture ring of the lens until the brightest image is projected onto the baseboard. Focus the image on the masking frame. Turn the lens’s aperture ring until you feel two clicks and see a slight darkening of the projected image. This should be 2 stops darker than the lens’s maximum aperture.

3. Check sharpness

Check for critical sharpness by using a focus finder if you have one, but remember to set it for your own eyesight first. Turn off the enlarger until ready for exposure. Now remove a sheet of paper and cut it up to use for test strips. You should be able to get roughly ten 10 x 5cm pieces from a 10 x 8in sheet.

4. Make a test strip


Place a Grade 2 filter into the enlarger, then place one of your cut pieces of paper on the masking frame. Expose for 5secs. Cover a 1cm strip of the paper with card and expose for another 5secs. Repeat until the last strip of paper has been exposed. Make sure you do not move the test paper as you move the card.

5. Developing the image

Place the exposed paper into the tray of developer and gently rock the solution back and forth, trying to get the paper submerged all at the same time. Timing is important – 1min for RC paper, but this will need longer in cold conditions. Avoid poking the paper with tongs as this can leave marks on the image.

6. Stop and fix

Remove the paper from the developer after the allotted time and drain briefly. Slide the paper into the stop bath and gently rock the stop bath tray for 10secs. Remove, drain and slide it into a tray of fixer, gently rocking again (10secs for test strips, 1-2mins for finished prints).

7. Review

Remove the test from the fix and view by white light (make sure your box of unexposed paper is closed). Counting from the lightest end of the test in fives, look for the first exposure that looks correct, and this will be your exposure time for the full print. This method will produce good ‘beginner’ prints.

8. Adjusting contrast

If the print is too high in contrast, replace the Grade 2 filter with a Grade 1 and re-test. If the improvement is only slight, move down to Grade 0 and re-test. However, if the print is grey and flat, replace the Grade 2 filter with a Grade 3 and re-test. If the improvement is only slight, move up another grade to 4 and re-test

9. Final print

When the correct exposure and contrast grade have been established, place a sheet in the masking frame and expose. Develop and stop as you did for the test, fix for 1min and wash for 5-10mins. Don’t leave prints in water for more than 30mins. Hang the fully washed print up to dry or lay it out on blotting paper.

Guide to Darkroom Printing: Things to Watch Out For

  • Be careful how you rock the trays. It’s easy to spill chemicals over the edge, so put plenty of newspaper under the trays in case of splashes
  • Drain off the excess from tests and prints before placing them in the next tray. This prolongs chemical life and reduces waste
  • Use one set of tongs to lift paper out of the developer and another set of tongs for stop and fix. Do not allow tongs to get mixed up, as fix will get into the developer and reduce its effectiveness
  • Always wrap up the paper and put the lid on after taking out what you need
  • Wash your hands each time you get any chemicals on them and don’t handle paper with fix on your fingers

Guide to Darkroom Printing: Troubleshooting

Having problems? Here are some common issues you may encounter and what causes them:

  • Photo paper black after development: Paper has been totally exposed to light
  • Photo paper has black edge after development: Paper is partially fogged, so the packet was probably left open
  • Paper is white after development: Paper unexposed
  • Paper is pink: Print not fixed
  • Print turns brown over time: Fix not washed off
  • White specks on final print: Dust and dirt on the negative
  • White fingerprint marks on finished print: You had fix on your fingers when you handled the paper