Day: January 26, 2021

Categories : Addiction Mental HealthTags :

Happier Memories in Teens Linked to Less Alcohol and Marijuana Use

On By ModernMedia

A study of teenage American students has found that happy childhood memories, along with a positive view of the present and outlook for the future are associated with reduced alcohol use, binge drinking and marijuana use. 

Researchers say that action is needed because COVID restrictions have left teenagers isolated and vulnerable. Quarantining results in anxiety, stress and feelings of loneliness in children and adolescents, and the closure of schools has also taken away mental health support systems which some teenagers may rely on.

John Mark Froiland of Purdue University said: “School often seems a source of stress and anxiety to students. This puts them at greater risk of not participating in lessons, getting lower grades and of substance misuse. Many teenagers also aren’t engaging with online learning during Covid or have lower engagement levels.

“But they’re more likely to be enthusiastic learners and not use drink and drugs if teachers take time to build more positive relationships with them. They can help students see that everything they’re learning is truly valuable. Parents have a role to play too.”

The study was based on questionnaires completed by 1961 student participants in San Francisco, of which 53% were female. The researchers examined how happy the students believed their childhood was, how happy they were currently and how optimistic they were about their futures.

In addition, they looked at alcohol and marijuana use over the past 30 days and binge use, as well as academic grades, behaviour during lessons and motivation.

Positive attitudes towards the past, present and future was associated with lower alcohol use, binge drinking and marijuana use, while the reverse was true for negative attitudes.

An optimistic outlook increased the likelihood that they would be motivated and focus on learning. Other findings included drinking being associated with marijuana use, and that girls had better behavioural engagement than boys.

Source: News-Medical.Net

Journal information: Froiland, J.M., et al. (2020) Positive and negative time attitudes, intrinsic motivation, behavioral engagement and substance use among urban adolescents. Addiction Research & Theory. doi.org/10.1080/16066359.2020.1857740.

Categories : Cardiovascular DiseaseTags :

Blood Vessels Self-Reinforce After Aneurysms

On By ModernMedia

Immediately following an aneurysm, blood vessels reinforce themselves by adapting collagen fibres to spread out the load, a study has found. 

An aneurysm is an abnormal bulge in the artery wall that can form in brain arteries. Brain aneurysms that rupture are fatal in nearly 50% of cases. In a rabbit model, the researchers used cutting-edge high-resolution microscopes to observe changes within the aneurysm, and observed that new collagen fibres laid down to deal with the strain and existing ones were re-oriented. Blood vessels had already been known to be able to reform and restructure over time, but this kind of primary restructuring is the first time that it has been observed, happening immediately after an event.  Instead of forming along the same direction, the blood vessels adapt to the different directions the new loads are in. 

Professor Anne Robertson at the University of Pittsburgh’s Swanson School of Engineering explained: “Imagine stretching a rubber tube in a single direction so that it only needs to be reinforced for loads in that direction. However, in an aneurysm, the forces change to be more like those in a spherical balloon, with forces pulling in multiple directions, making it more vulnerable to bursting. Our study found that blood vessels are capable of adapting after an aneurysm forms. They can restructure their collagen fibers in multiple directions instead of just one, making it better able to handle the new loads without rupturing.

“The first restructuring phase involves putting down a layer collagen fibres in two directions to deal with the new load, and the second phase involves re-orienting existing layers to adjust to these two directions, explained Chao Sang, who was a primary investigator on this research as part of his doctoral dissertation.

“The long-term restructuring is akin to a scar forming after a cut has healed, while this first phase that we observed can be thought of as having a role similar to clotting immediately after the cut–the body’s first response to protect itself,” added Robertson, who has a secondary appointment in the Swanson School’s Department of Bioengineering. “Now that we know about this first phase, we can begin to investigate how to promote it in patients with aneurysms, and how factors like age and preexisting conditions affect this ability and may place a patient at higher risk for aneurysm rupture

Source: News-Medical.Net

Journal information: Sang, C., et al. (2020) Adaptive Remodeling in the Elastase-Induced Rabbit Aneurysms. Experimental Mechanics. doi.org/10.1007/s11340-020-00671-9.

Categories : Cancer Diet and NutritionTags :

Breast Cancer in Mice Inhibited by Restricted Feeding Times

On By ModernMedia

Restricting calorie intake to an eight-hour window coinciding with physical activity reduced breast cancer risk in female mouse models.

Researchers from University of California San Diego School of Medicine, Moores Cancer Center and Veterans Affairs San Diego Healthcare System (VASDSH) found that the restricted feeding times, which are kind of circadian rhythm-linked intermittent fasting, enhanced metabolic health and tumour circadian rhythms in female mice with obesity-driven postmenopausal breast cancer. Breast cancer is the second most common cancer in US women, after skin cancer.

“Previous research has shown that obesity increases the risk of a variety of cancers by negatively affecting how the body reacts to insulin levels and changing circadian rhythms,” explained senior author Nicholas Webster, PhD. professor at UC San Diego School of Medicine and senior research career scientist at VASDSH. “We were able to increase insulin sensitivity, reduce hyperinsulinemia, restore circadian rhythms and reduce tumor growth by simply modifying when and for how long mice had access to food.”

Female mouse models mimicking postmenopausal hormone conditions were used to investigate if time-restricted feeding of obese mice affected the tumour growth and development, and reduced metastasis to the lungs. The mice were split into three groups, one with constant access to food, one with access for eight hours at night when they have the greatest activity, and the last was fed an unrestricted low-fat diet.

Obesity and menopause disrupt the circadian rhythm, with increased risk of insulin resistance and thereby chronic diseases such as cancer. A number of cancers are known to be associated with insulin resistance, such as breast cancer and pancreatic cancer. High insulin levels in obese mice drive tumour growth. Artificially increasing insulin levels has been shown to accelerate tumour growth whilst lowering them is similar to the effect of limiting eating.
Manasi Das, PhD, postdoctoral fellow in the Webster lab and first author, said: “Time-restricted eating has a positive effect on metabolic health and does not trigger the hunger and irritability that is associated with long-term fasting or calorie restriction. Through its beneficial metabolic effects, time-restricted eating may also provide an inexpensive, easy to adopt, but effective strategy to prevent and inhibit breast cancer without requiring a change in diet or physical activity.”

Webster believes that time-restricting eating warrants further investigations as it may present a way to reduce breast cancer risk, or that of cancer in general.

“The increase in risk of breast cancer is particularly high in women who are overweight and have been through menopause. For this reason, doctors may advise women to adopt weight loss strategies to prevent tumor growth,” said Das. “Our data suggests that a person may benefit from simply timing their meals differently to prevent breast cancer rather than changing what they eat.”

Source: Medical Xpress

Journal information: Manasi Das et al. Time-restricted feeding normalizes hyperinsulinemia to inhibit breast cancer in obese postmenopausal mouse models, Nature Communications (2021). DOI: 10.1038/s41467-020-20743-7

Categories : COVIDTags :

EU to Restrict AstraZeneca Exports to Tackle Vaccine Shortage

On By ModernMedia

In response to AstraZeneca’s COVID vaccine production and delays, the European Union has warned that it will tighten exports of the company’s vaccine to countries outside its borders.

EU Health Commissioner Stella Kyriakides warned it would “take any action required to protect its citizens”, adding that she had requested detailed delivery schedules and a meeting next week with the company. She added that “in the future, all companies producing vaccines against Covid-19 in the EU will have to provide early notification whenever they want to export vaccines to third countries”.

The vaccine, developed by Oxford University and the British-Swedish company AstraZeneca, is still yet to be approved in the EU but should receive it by the end of January, with distribution set to start on the 15th of February. The EU has been suffering from a number of vaccination programme setbacks, including a previous announcement last week from Pfizer that its own deliveries were being delayed in order to upgrade manufacturing capabilities at a plant in Belgium, provoking ire amongst EU politicians. Italy’s PM has resigned over handling of the pandemic.

The EU had signed a deal in August to secure 300 million doses from AstraZeneca, with an option for another 100 million. Last week, AstraZeneca had announced a slowdown in delivery due to “reduced yields at a manufacturing site within our European supply chain”. The problem is thought to be from a manufacturing plant also in Belgium, which is run by an AstraZeneca partner firm. The exact size of the shortfall is not known but some believe it to be a drop of 31 million doses, or 60% of those meant to be delivered by the end of the quarter.

Where this leaves low and middle-income countries counting on the Oxford/AstraZeneca vaccines is unclear, but it certainly will add to mounting tension between countries seeking vaccines for their populations amidst the spread of more contagious COVID variants. President Cyril Ramaphosa warned in an address to the World Economic Forum that vaccine nationalism was a growing concern and threat to global recovery. The African Union’s vaccine task team has thus far managed to secure only 270 million doses.

Source: BBC News