Day: September 28, 2021

Categories : Environmental EffectsTags :

Solar Exposure Guidelines Could be Revised

On By ModernMedia
Photo by Amy Humphries on Unsplash

Previously published solar exposure guidelines for optimal vitamin D synthesis that were based on a study of skin samples may have to be revised. 

A study published in PNAS has tested the optimum ultraviolet radiation (UVR) wavelengths for human skin production of vitamin D in sunlight.

Though UVR from sunlight can cause sunburn and skin cancer, it is the most important source of vitamin D.

Public health advice on sunshine exposure balances its risk and benefit, which is not a simple task because the health outcomes from UVR exposure vary considerably with wavelength within the sun’s UVR spectrum. For example, the sun’s UVR contains less than 5% short wavelength UVB radiation but this is responsible for over 80% of the sunburn response. Each health outcome from solar exposure has its own unique wavelength dependency.

The link between specific UVB wavelengths and vitamin D production was determined more than thirty years ago in ex vivo skin samples. However, the finding is less well established, with doubts on its accuracy which compromise risk/benefit calculations for optimal solar exposure.

Researchers led by the Professor Antony Young from King’s College London measured blood vitamin D levels in 75 healthy young volunteers, before, during, and after partial or full body exposure to five different artificial UVR sources with different amounts of UVB radiation, to gauge the trade-off between solar exposure benefits, which include vitamin D synthesis, versus the risks of sunburn and skin cancer.

The results were compared against predictions from the old ex vivo vitamin D study, finding that it was not an accurate predictor of benefit from UVR exposure.

The authors’ recommendation is a systematic correction of the ex vivo wavelength dependency for vitamin D. The new study means that many risk benefit calculations for solar UVR exposure must be reviewed with a revised version of the wavelength dependency for vitamin D.

“Our study shows that risk versus benefit calculations from solar exposure may need to be re-evaluated. The results from the study are timely because the global technical committee, Commission internationale de l’éclairage, that sets UVR standards will be able to discuss the findings of this paper to re-evaluate the wavelength dependency of vitamin D. Further research from our group will determine the risk/benefit calculations.”

Professor Antony Young, King’s College London

Source: King’s College London

Categories : CancerTags :

SSRI Antidepressants Could be Used To Fight Cancer

On By ModernMedia
Natural killer (NK) cells target a cancel cell for destruction. Credit: NCI

Long used to treat depression, selective serotonin reuptake inhibitors (SSRIs) could help improve modern cancer treatments.

In mouse experiments, they slowed the growth of pancreatic and colon cancers, and when combined with immunotherapy, they even halted cancer growth long-term. In some cases the tumours disappeared completely. The researchers’ findings will now be tested in human clinical trials.

The neurotransmitter serotonin, known as the happiness molecule, has many other functions and is mostly found outside the brain, stored in blood platelets. Serotonin reuptake inhibitors (SSRIs), which are used to treat depression, increase serotonin levels in the brain but reduce serotonin in platelets.

Serotonin was already known to be involved  in carcinogenesis. Until now, however, the underlying mechanisms had remained obscure. Now, researchers at the University of Zurich (UZH) and University Hospital Zurich (USZ) have shown that SSRIs or other drugs that lower peripheral serotonin levels can also slow cancer growth in mice.

Pierre-Alain Clavien, Director, Department of Surgery and Transplantation, University of Zurich, said: “Drugs that are already approved for clinical use as antidepressants could help improve treatment of hitherto incurable pancreatic and colorectal cancers.”

Although recent years have seen new, effective treatments such as targeted antibodies or immunotherapies, most patients with advanced-stage abdominal tumours such as colon or pancreatic cancer die within a few years of diagnosis. Tumour cells eventually become resistant to the drugs and are no longer recognised by the immune system. Now, the researchers have discovered the role serotonin plays in this tumour cell resistance mechanism.

Cancer cells use serotonin to boost production of an immunoinhibitory molecule, PD-L1, which binds to killer T cells, rendering them dysfunctional. The cancer cells thus escape destruction by the immune system. In mouse models, the researchers were able to show that SSRIs or peripheral serotonin synthesis inhibitors prevent this mechanism. “This class of antidepressants and other serotonin blockers cause immune cells to recognise and efficiently eliminate tumor cells again. This slowed the growth of colon and pancreatic cancers in the mice,” Clavien said.
PD-L1, via which serotonin exerts its effect, is also the target of modern immunotherapies, also called immune checkpoint inhibitors. The researchers then tested a dual treatment approach in mice: immunotherapy, which increases the activity of killer T cells, was combined with drugs that reduce peripheral serotonin. Cancer growth was suppressed in the animal models in the long term, and in some mice, the tumours disappeared completely.

“Our results provide hope for cancer patients, as the drugs used are already approved for clinical use. Testing such drug combinations on cancer patients in clinical trials can be fast-forwarded due to the known safety and efficacy of the drugs,” said Clavien.

Source: University of Zurich

Categories : Cardiovascular DiseaseTags :

Home BP Monitoring Gets the Thumbs-up From Patients

On By ModernMedia
BP cuff for home monitoring, Source: Pixabay

Adults needing to track their blood pressure regularly for a hypertension diagnosis preferred home monitoring blood pressure versus at a clinic, kiosk or with a 24-hour wearable device, according to preliminary research presented at the American Heart Association’s Hypertension Scientific Sessions 2021.

According to the American Heart Association, about half of US adults have hypertension, and of those with high blood pressure (BP) over a third are unaware they have it. H

“Most hypertension is diagnosed and treated based on blood pressure measurements taken in a doctor’s office, even though the U.S. Preventive Services Task Force and the American Heart Association recommend that blood pressure measurements be taken outside of the clinical setting to confirm the diagnosis before starting treatment,” said lead study author Beverly Green, MD, MPH, senior investigator and family physician at Kaiser Permanente Washington Health Research Institute. “It is the standard that blood pressure monitoring should be done either using home blood pressure monitoring or 24-hour ambulatory blood pressure monitoring prior to diagnosing hypertension.”

The “gold standard” for out-of-office measurement to determine a diagnosis of high blood pressure is 24-hour ambulatory blood pressure monitoring devices, worn day and night to take continuous blood pressure readings. Measuring BP on a home device with a normal BP cuff, can be more convenient.

The researchers studied adherence and acceptability of different blood pressure measuring methods among 510 adults with elevated BP but without a hypertension diagnosis. Participants in the study were an average age of 59 years old; half were male; the average BP was 150/88 mm Hg and were taking blood pressure-lowering medications.

Participants were randomised to either clinic measurements, home monitoring or kiosk blood pressure monitoring.

Those in the group for clinic measurements were asked to return to the clinic for at least one additional blood pressure check, as is routine in diagnosing hypertension in clinical practice. The home group received home blood pressure machines and the training to use them, and were asked to measure their blood pressure twice in a row, two times daily, for five days, for a total of 20 measurements. The kiosk group was asked to take their blood pressure at a kiosk in their clinic or at a nearby pharmacy three times each on three separate days, for a total of nine measurements. All participants were asked to complete their group-assigned diagnostic regimens within three weeks, and then to complete 24-hour ambulatory blood pressure monitoring. Researchers compared adherence to and the acceptability among each diagnostic method.

They measured adherence to monitoring by noting the percent of individuals in each group who completed their assigned measurement method as instructed. They measured acceptability with questionnaires.

Researchers found that overall acceptability was highest for the at-home group, followed by the clinic and kiosk groups, while 24-hour ambulatory blood pressure monitoring was the least popular. Adherence to the monitoring regimen was lowest in the kiosk group, but more than 90% in the home testing group; more than 87% in the clinic group; nearly 68% in the kiosk group; and 91% for 24-hour ambulatory monitoring among all participants.

“Home blood pressure monitoring was the most preferred option because it was convenient, easy to do, did not disturb their daily personal or work routine as much, and was perceived as accurate,” said Dr Green. “Participants reported that ambulatory blood pressure monitoring disturbed daily and work activities, disrupted sleep and was uncomfortable.”

When asked which diagnostic testing regimen they would prefer, more than half chose home blood pressure monitoring, especially if they were assigned to the home group, where almost 80% preferred home monitoring.

Dr Green suggests that clinicians routinely offer home blood pressure monitoring to their patients with elevated blood pressure.
“Health care professionals should work toward relying less on in-clinic visits to diagnose hypertension and supporting their patients in taking their blood pressure measurements at home,” Dr Green said. “Home blood pressure monitoring is empowering and improves our ability to identify and treat hypertension, and to prevent strokes, heart attacks, heart failure and cardiovascular death.”

Source: American Heart Association

Categories : COVIDTags : 1 Comment

Two Ivermectin Deaths Reported in US State

On By ModernMedia
Source: Unsplash

Two deaths in the US state of New Mexico have been linked to misuse of ivermectin, the anti-parasitic medicine that has repeatedly been used by people as an anti-COVID medication.

The patients were among 14 in the state who had been hospitalised after being poisoned by the use of ivermectin, which has been widely promoted.

Dr David Scrase, the acting head of the state health department, said the two patients who died (38 and 79 years old) had both contracted the coronavirus and attempted to treat it themselves with ivermectin, leading to kidney failure in one patient.

“It’s the wrong medicine for something really serious,” Dr Scrase said.

The American Association of Poison Control Centers reported 1440 cases of ivermectin poisoning up to 20 September, more than three times seen in the same period in 2019 and 2020. A majority of this year’s reports came over the past few months as people sought prescriptions after false claims about the drug’s effectiveness in COVID patients started to circulate on social media, podcasts and talk radio. Many other states are seeing increasing cases of ivermectin poisoning.

Dr Susan Smolinske, the director of the New Mexico Poison and Drug Information Center, said that about half of the reported cases of ivermectin poisoning this year were people who took the drug to prevent COVID.

While certain versions of ivermectin are prescribed to humans to treat head lice and other parasites, other more concentrated formulations are commonly used in the equine and livestock industries to combat worms and parasites.

Previously, Dr Smolinske said, many of the incidents in New Mexico involved children mistakenly taking chewable tablets intended for dogs, however the poison centres had recently seen more instances of people taking concentrated forms of the drug intended for large animals, which may contain other ingredients not intended for human use.

“Most of our cases are of the horse or dewormer or pour-on product, so they’re highly concentrated compared to those tablets for dogs,” said Dr Susan Smolinske, the director of the New Mexico Poison and Drug Information Center.

Dr Smolinske said misuse of the drug can cause drowsiness, dizziness, tremors or even a coma. “It gets into the brain, and if you take a high enough dose, it has difficulty getting out of the brain,” she said.

Source: New York Times

Categories : CancerTags :

Oxford-AstraZeneca Vaccine Tech Tapped to Treat Cancer

On By ModernMedia
Source: National Cancer Institute on Unsplash

The Oxford-AstraZeneca vaccine’s success against SARS-CoV-2 has prompted scientists to develop a vaccine for cancer, using Oxford’s viral vector vaccine technology.

When tested in mouse tumour models, the two-dose therapeutic cancer vaccine increased the numbers of anti-tumour T cells infiltrating the tumours and improved the efficacy of cancer immunotherapy. Compared to immunotherapy alone, combination with the vaccine resulted in a greater reduction in tumour size and improved survival.

The study, which was done by Professor Benoit Van den Eynde’s group at the Ludwig Institute for Cancer Research, University of Oxford in collaboration with co-authors Professor Adrian Hill and Dr Irina Redchenko at the University’s Jenner Institute, has been published in the Journal for ImmunoTherapy of Cancer.

Cancer immunotherapy has improved outcomes for some cancer patients. Anti-PD-1 immunotherapy works by unleashing anti-tumour T cells to allow them to kill cancer cells. However, in the majority of cancer patients, anti-PD-1 therapy is still ineffective .

One reason for the poor efficacy of anti-PD-1 cancer therapy is that some patients have low levels of anti-tumour T cells. Oxford’s vaccine technology generates strong CD8+ T cell responses, which are necessary for strong anti-tumour effects.

The team developed a two-dose therapeutic cancer vaccine with different prime and boost viral vectors, one of which is the same as the vector in the Oxford-AstraZeneca COVID vaccine. In order to create a vaccine treatment that specifically targets cancer cells, the vaccine was designed to target two MAGE-type proteins found on the surface of many types of cancer cells.

Preclinical experiments in mouse tumour models demonstrated that the cancer vaccine increased the levels of tumour-infiltrating CD8+ T cells and enhanced the response to anti-PD-1 immunotherapy. The combined vaccine and anti-PD-1 treatment resulted in a greater reduction in tumour size and improved the survival of the mice compared to anti-PD-1 therapy alone.

Benoit Van den Eynde, Professor of Tumour Immunology at the University of Oxford, said: “We knew from our previous research that MAGE-type proteins act like red flags on the surface of cancer cells to attract immune cells that destroy tumours.

“MAGE proteins have an advantage over other cancer antigens as vaccine targets since they are present on a wide range of tumour types. This broadens the potential benefit of this approach to people with many different types of cancer.

“Importantly for target specificity, MAGE-type antigens are not present on the surface of normal tissues, which reduces the risk of side-effects caused by the immune system attacking healthy cells.”

Human trials in 80 patients with non-small cell lung cancer will be launched later this year.

Adrian Hill, Lakshmi Mittal and Family Professorship of Vaccinology and Director of the Jenner Institute, University of Oxford, said: “This new vaccine platform has the potential to revolutionise cancer treatment. The forthcoming trial in non-small cell lung cancer follows a Phase 2a trial of a similar cancer vaccine in prostate cancer undertaken by the University of Oxford that is showing promising results.

“Our cancer vaccines elicit strong CD8+ T cell responses that infiltrate tumours and show great potential in enhancing the efficacy of immune checkpoint blockade therapy and improving outcomes for patients with cancer.”

Source: Oxford University