Tag: 18/8/21

Categories : COVIDTags :

Keeping an Eye on B.1.621’s Immune Escape Potential

On By ModernMedia
Source: Viktor Forgacs on Unsplash

First detected in Colombia in January, the SARS-CoV-2 variant B.1.621 was recently named a ‘variant of interest’ by the European Centre for Disease Prevention and Control, reports MedPage Today. So far, neither the World Health Organization nor the CDC has elevated it to this status and it hasn’t received a greek letter designation yet.

B.1.621 has been detected in the US, though it (along with version B.1.621.1) currently accounts for just about 1% of all cases in the country. In the state of Florida, though, recent data from the University of Miami showed that 9% of cases in the Jackson Memorial Health System were B.1.621 as of the second week of July.

Last week, seven residents in a Belgian nursing home died after being infected with B.1.621, despite the fact that all of them had been vaccinated (though which vaccine was not disclosed. All of the deceased were in their 80s or 90s, and some were in poor health already, according to virologist Marc Van Ranst, who conducted tests on the virus found in the nursing home, Reuters reported. A total of 21 residents had been infected with the variant, along with several staff members. However, infected staff only had mild symptoms. B.1.621 makes up less than 1% of known cases in Belgium overall, according to Reuters.

Public Health England said that as of 2 August, there have been 32 cases (PDF) of the variant in England, with the majority (19%) being detected in London. This new variant has E484K and K417N mutations, making it similar to the Beta variant (B.1.351), prompting concern that B.1.621 could have similar immune escape properties, the agency noted.

In a recent risk assessment (PDF), Public Health England said that there is lab evidence of a reduction in pseudovirus neutralisation in the serum of vaccinated or previously Delta-infected individuals.
However, the agency noted that the trajectory of this new variant depends on its growth and expansion, and currently there’s no sign that it’s outcompeting Delta and it also seems unlikely that it’s more contagious. Still, its immune escape properties could contribute to future changes in growth, they warned, and other epidemiological events could influence whether it becomes established in the UK.

A recent paper in Lancet Infectious Diseases found two cases of B.1.621 involving community transmission, at a time when 99% of cases were due to the Delta variant. Both of these cases however occurred among unvaccinated individuals.

However, the dominance of Delta seems to be keeping other variants at bay, at least for now.

Source: MedPage Today

Categories : Mental HealthTags :

Histamine Involvement in Depression Revealed

On By ModernMedia
Image by Falkurian Design on Unsplash

Histamine from inflammation dampens serotonin levels and antidepressants’ ability to boost them, according to experiments in mice models.

The findings, published in The Journal of Neuroscience add to mounting evidence that inflammation, and the accompanying release of the molecule histamine, affects serotonin, a key molecule responsible for mood in the brain.

Inflammation triggers the release of histamine in the body, increasing blood flow to affected areas to flood them with immune cells. While these effects help the body fight infections, both long-term and acute inflammation is increasingly linked to depression. There is already strong evidence that patients with both depression and severe inflammation are the ones most likely not to respond to antidepressants.

Dr Parastoo Hashemi, Lead Author, Imperial’s Department of Bioengineering, said: “Our work shines a spotlight on histamine as a potential key player in depression. This, and its interactions with the ‘feel-good molecule’ serotonin, may thus be a crucial new avenue in improving serotonin-based treatments for depression.”

Chemical messengers
Serotonin is a key target for depression-tackling drugs, and selective serotonin reuptake inhibitors (SSRIs) inhibit the re-absorption of serotonin in the brain, allowing it to circulate for longer and improve mood.

However, although SSRIs bring relief to many who take them, an increasing number of people are resistant to it. This could be due to the specific interactions between chemical messengers, or neurotransmitters, including serotonin and histamine.

With this in mind, researchers set out to investigate the relationship between histamine, serotonin, and SSRIs. They created tiny serotonin-measuring microelectrodes and put them into the hippocampus of the brains of live mice, an area known to regulate mood. The technique, known as fast scan cyclic voltammetry (FSCV), allowed them to measure brain serotonin levels in real time..

After placing the microelectrodes, they injected half the mice with lipopolysaccharide (LPS), an inflammation-causing toxin found in some bacteria, and half the mice with a saline solution as a control.

Within minutes of LPS injection, brain serotonin levels dropped, whereas they remained the same in control mice, demonstrating the rapid action of inflammatory responses on the brain and serotonin. Since LPS cannot cross the blood-brain barrier, it could not cause the drop in serotonin.
The inflammatory response triggered histamine in the brain which directly inhibited the release of serotonin by attaching to inhibitory receptors. 

To counter this, the researchers administered SSRIs to the mice, but they were much less able to boost serotonin levels than in control mice. They posited that this is because the SSRIs directly increased the amount of histamine in the brain, cancelling out its serotonin boosting action.

The researchers then administered histamine reducing drugs alongside the SSRIs to counter histamine’s inhibitory effects, and saw serotonin levels rise back to control levels. This appears to confirm the theory that histamine directly dampens serotonin release in the mouse brain. These histamine reducing drugs cause a whole-body reduction in histamine and are distinct from antihistamines taken for allergies, which block histamine’s effects on neurons.

A new molecule of interest
More work is needed before progressing to human studies. However, it is not currently feasible to use microelectrodes to make similar measurements in human brains, so the researchers are now looking at other ways to get a snapshot of the brain by looking at other organs which use serotonin and histamine, like the gut.

Source: Imperial College London

Categories : CancerTags :

Fewer Side Effects in New Breast Cancer Therapy

On By ModernMedia
Breast cancer cells. Image source: National Cancer Institute on Unsplash

Researchers have shown that a new treatment for breast cancer using an antibody linked to a cytotoxic drug is as effective as the previous combination, but with less side effects. The study was published in JAMA Oncology.

The development of treatment with antibodies directed towards HER2 positive breast cancer trastuzumab and pertuzumab, has proven the possibility of improved treatment and cure of this cancer type if these antibodies are combined with chemotherapy, often taxaner. Preoperative (neoadjuvant) treatment with this combination confers complete response in a high proportion of cases. Trastuzumab emtansine (T-DM1) consists of trastuzumab (T) and the cytotoxic substance emtansine (DM1) which clinical trials have shown have good efficacy and low toxicity.

The randomised phase II study PREDIX HER2 was conducted at 9 Swedish clinics to investigate the effect (the proportion of complete response after neoadjuvant treatment) of this treatment in relation to frequency and degree of side effects. The standard treatment was a combination of docetaxel, trastuzumab and pertuzumab which was compared with T-DM1 as experimental treatment, and patients received 6 treatments every 3rd week. The treatment effect was monitored with mammography and PET-CT with 18- fluorodeoxyglucose (18F-FDG). Tissue and blood samples were regularly taken from the patients for later analysis.

The study showed that the effect measured as pathologic complete response was similar in both treatment groups. With T-DM1 treatment, the frequency and degree of side effects was significantly lower and quality of life was higher during treatment. After a median follow up time of 40,4 months no difference was observed between the treatment groups.

In conclusion, the study showed that both treatments were equally efficient, but with fewer side effects in patients treated with T-DM1. A phase III study will allow definitive conclusions to be drawn regarding the efficiency. Meanwhile, the collected samples are being analysed to investigate factors which can explain the response in individuals.

Source: Karolinska Institute

Categories : Diet and NutritionTags :

Extra Vitamin D Does not Boost Muscles

On By ModernMedia
Photo by Michele Blackwell on Unsplash

Vitamin D supplementation does not have beneficial effects on muscle function, strength, or mass, according to a new meta-analysis, and may even have detrimental effects on muscle strength in people with normal levels of the vitamin.

Vitamin D deficiency, causes a generalised decrease in bone mineral density, resulting in osteopenia and osteoporosis. In young children who have little mineral in their skeleton, this defect results in a variety of skeletal deformities classically known as rickets. It is also believed to cause muscle weakness; affected children have difficulty in standing and walking, whereas the elderly have increasing sway and more frequent falls,thereby increasing their risk of fracture.

The analysis, which is published in the Journal of Bone and Mineral Research, included 54 trials involving 8747 individuals. Overall, no benefits of vitamin D over placebo were observed for improving muscle health. On the contrary, vitamin D appeared to have detrimental effects in terms of increased time spent performing what’s called the Timed Up and Go test, a decrease in maximum strength at knee flexion, and a tendency towards a reduced score of the Short Physical Performance Battery.

“Care should be taken recommending vitamin D supplementation to improve muscle strength and function in people with normal or only slightly impaired vitamin D status,” said lead author Lise Sofie Bislev, MD, PhD, of Aarhus University Hospital, in Denmark. “We need to study further whether it may benefit muscles in those with severe vitamin D deficiency, however.”

Source: Wiley

Categories : AllergiesTags :

Allergies in Childhood Linked to Developing Tree Nut Allergies

On By ModernMedia
Photo by Pavel Kalenik on Unsplash

A Swedish study found that while allergic sensitivity to tree nuts was common in adults, most people never experienced symptoms.

Allergies to tree nuts are common and have become an important health concern as availability has increased. Tree nuts include hazelnuts, walnuts, pecans, cashews, pistachios, almonds, and brazil nuts.Tree nuts, as a group, are one of the eight most common allergens, and allergic reactions to them can be severe. Availability of tree nuts has increased both in the raw form and within processed foods and bakery products; tree nut utilisation has increased by 1kg per capita from 1980 to 2015. Research has shown that the consumption of nuts has positive cardiovascular effects, such as decreasing cholesterol, triglycerides, and fasting blood glucose, and this has encouraged consumption.

The study, with a total of 2215 participants, found that eczema, asthma, and egg allergies at an early age were associated with developing a tree nut allergy by adulthood. Additionally, the researchers found allergen molecules to be better diagnostic tools for predicting allergic symptoms to tree nuts compared with analysing allergen extracts. The study was published in Clinical and Experimental Allergy.

“This study increases the understanding of tree nut allergy in a general population, followed from infancy up to adulthood. For example, our study reveals that most extract‐based tree nut‐sensitised individuals do not have tree nut allergy and hence extract-based testing for tree nuts without a specific clinical suspicion should not be performed,” said co–lead author Jessica Bager, of the Karolinska Institute.

Source: Wiley

Categories : COVIDTags :

SA’s Department of Tourism Aims to Join Vaccine Passport System

On By ModernMedia
Image by Quicknews

The Department of Tourism says that it wants to introduce a vaccine passport for South Africa, but a number of international and legislative obstacles have to be overcome.

A lack of standardisation around vaccine passports worldwide is a key issue, said tourism director-general Nkhumeleni Victor Tharage in a briefing to Parliament on 17 August.

“Even in some jurisdictions that have opted to apply this (passport), there isn’t yet a sense of uniformity. When we don’t have a single, standardised specimen, it is a little bit difficult to say which one is which.

“If South Africa introduces (a passport), and there is access to information from the National Institute for Communicable Diseases (NICD) that confirms that a person has been vaccinated, the question is if that person arrives Lagos (Nigeria), what resources will they use to verify this information that is stored on a database in South Africa?”

South Africa has the same problem when it comes to verification of incoming tourists, Tharage said. The government was also cautious about introducing a vaccine passport system that is discriminatory against certain groups of people, he noted.

“When we reopen, and when everyone is starting to travel, it should not be discriminatory. And that principle has been reiterated time and time again.”

The vaccine passport could be a requirement for events, and Tharage said he was confident that this is something that the government could introduce with ease on short notice.

“At the end of the day, it’s about being able to get the necessary confidence from consumers, tourists and trade. If we don’t do that, then there will be a negative impact on our recovery.”

However, Department of Health spokesperson Foster Mohale affirmed that South Africa has no immediate plans to require proof of vaccination for any purpose.

Open for tourism
Transport minister Fikile Mbalula has said that his department is working with businesses to ensure that South Africa successfully reopens for international travel. Presenting his departmental budget speech at the end of May, Mbalula said that South Africa must ensure that it joins the increasing number of countries which accept the International Air Transport Association’s (IATA) mobile travel pass.

The travel pass is a mobile app that helps travellers store and manage their verified certifications for COVID tests or vaccines, and is more secure and efficient than current paper processes, IATA said. This is important given the potentially enormous scale of testing or vaccine verifications that the group must securely manage. IATA said it is looking to introduce further changes, such as QR code scanning by immigration officials.

Source: BusinessTech