Researchers have developed a new technique to improve understanding of how acid damages teeth over time at the microstructural level, creating a clear picture of how the damage happens.
Dentine forms the main bulk of human teeth and supports the enamel, which covers the crown surface, helping to make teeth strong and resilient, but acids from dental plaque can cause tooth decay affecting the dental structure’s integrity. This research aims to develop knowledge that leads to new treatments that can restore the structure and function of dentine.
Using in situ synchrotron X-ray microtomography to scan dentine samples while they were being treated with acid, researchers built clear 3D images of dentine’s internal structure with sub-micrometre resolution (a micrometre being one-thousandth of a millimetre). By analysing these images over the six hours of the experiment, the researchers conducted the first-ever time-resolved 3D study (otherwise known as 4D studies) of the dentine microstructural changes caused by acid.
The study, published in Dental Materials, shows that acid dissolves minerals in different structures of dentine at different rates.
Research leader Dr Tan Sui, Senior Lecturer in Materials Engineering at the University of Surrey, known for her work creating improved bio-inspired materials, said:
“Relatively little is known about how exactly acid damages the dentine inside our teeth at a microstructural level. This new research technique changes that and opens the possibility of helping identify new ways to protect dental tissues and develop new treatments.”
In BMJ Case Reports, doctors suggest investigating the use of cannabidiol (‘CBD’) oil as a potential lung cancer treatment, after dealing with a daily user whose lung tumour shrank in the absence of conventional treatment.
The body’s own endocannabinoids are involved in various processes, including nerve function, emotion, energy metabolism, pain and inflammation, sleep and immune function.
Cannabinoids are chemically similar to these, and can interact with signalling pathways in cells, including cancer cells. While they have been studied for use as a primary cancer treatment, there have been inconsistent results.
Despite treatment advances, survival rates for non-small cell lung cancer remain low at around 15% five years after diagnosis, with average survival without treatment is about seven months.
The authors describe the case of a woman in her 80s, a pack-a-week smoker diagnosed with non-small cell lung cancer. The woman also had mild chronic obstructive pulmonary disease (COPD), osteoarthritis, and hypertension, for which she was taking various drugs.
Her tumor was 41 mm in size at diagnosis, with no evidence of local or further spread, so was suitable for conventional treatment of surgery, chemotherapy, and radiotherapy. But the woman refused treatment, so was placed under ‘watch and wait’ monitoring, which included regular CT scans every 3-6 months.
These showed that the tumor was progressively shrinking, reducing in size from 41 mm in June 2018 to 10 mm by February 2021, equal to an overall 76% reduction in maximum diameter, averaging 2.4% a month, say the report authors.
When contacted in 2019 to discuss her progress, the woman revealed that she had been taking CBD oil as an alternative self-treatment for her lung cancer since August 2018, shortly after her original diagnosis.
She had done so on the advice of a relative, after witnessing her husband struggle with the side effects of radiotherapy. She reported consistently taking 0.5 ml of the oil, two to three times a day.
According to the supplier, the main active ingredients were Δ9-tetrahydrocannabinol (THC) at 19.5%, cannabidiol at around 20%, and tetrahydrocannabinolic acid (THCA) at around 24%.
The supplier also said that she should avoid hot food or drinks when taking the oil as she might otherwise feel stoned. The woman reported reduced appetite since taking the oil but had no other obvious ‘side effects’. There were no other changes to her prescribed medications, diet, or lifestyle, and she continued smoking throughout.
The authors cautioned that this is just one case report, with only one other similar case reported, and it is unclear which of the CBD oil ingredients might have been helpful.
“We are unable to confirm the full ingredients of the CBD oil that the patient was taking or to provide information on which of the ingredient(s) may be contributing to the observed tumour regression,” they pointed out.
They further emphasised that, “although there appears to be a relationship between the intake of CBD oil and the observed tumuor regression, we are unable to conclusively confirm that the tumor regression is due to the patient taking CBD oil.”
The authors concluded that, “more research is needed to identify the actual mechanism of action, administration pathways, safe dosages, its effects on different types of cancer and any potential adverse side effects when using cannabinoids.”
A paper awaiting peer review on the MedRxiv preprint server shows that menstrual changes in women receiving after the COVID vaccine are quite common.
Many people began sharing that they experienced unexpected menstrual bleeding after being vaccinated for COVID, an emerging phenomenon which was undeniable yet understudied.
Unfortunately, dismissal by medical experts fueled greater concerns, as both vaccine hesitant and anti-vaccine individuals and organisations began to conflate the possibility of short-term menstrual changes with long-term harms to fertility. Many influencers used this well-used framing of protecting women as a means of further anti-vaccine messages.
There are many plausible biological mechanisms that could explain a relationship between an acute immune challenge such as a vaccine, its corresponding and well-known systemic effects on haemostasis and inflammation, and menstrual repair mechanisms of the uterus. The uterine reproductive system is flexible and adaptable in the face of stressors. Examples include marathon running having short term influence on hormone concentrations in the short term; short-term calorie restriction that results in a loss of menstrual cycling can be overcome by resuming normal feeding; that inflammation influences ovarian hormones; and that psychosocial stressors can correspond to cycle irregularity and yet resilience can buffer one from these harms. Typhoid, Hepatitis B, HPV vaccines have all had menstrual irregularity associated with them.
While sustained early stressors can influence adult hormone concentrations, short-term stressors resolve and do not produce long-term effects. This is quite different from the sustained immune assault of COVID itself: studies and anecdotal reports are already demonstrating that menstrual function may be disrupted long-term, particularly in those with long COVID.
In this sample, 42% of people with regular menstrual cycles bled more heavily than usual, while 44% reported no change, after being vaccinated. Among people who typically do not menstruate, 71% of people on long-acting reversible contraceptives, 39% of people on gender-affirming hormones, and 66% of post-menopausal people reported breakthrough bleeding. We found increased/breakthrough bleeding was significantly associated with age, other vaccine side effects such as fever or fatigue, history of pregnancy or birth, and ethnicity.
Many respondents who had post-vaccine changes did not have them until fourteen days or longer post-inoculation, which extends beyond the typical seven days of adverse symptom reporting in vaccine trials.
While chronically high cholesterol levels are linked to increased risks of breast cancer and worse outcomes in most cancers, the link had not been fully understood until now.
In a study published in Nature Communications, researchers identify the mechanisms at work, describing how breast cancer cells utilise cholesterol to develop stress tolerance, preventing them from dying as they migrate from the original tumour site.
“Most cancer cells die as they try to metastasise – it’s a very stressful process,” said senior author Donald P. McDonnell, Ph.D., professor in the departments of Pharmacology and Cancer Biology and Medicine at Duke University School of Medicine. “The few that don’t die have this ability to overcome the cell’s stress-induced death mechanism. We found that cholesterol was integral in fueling this ability.”
McDonnell and colleagues built on earlier research in their lab focusing on the link between high cholesterol and oestrogen-positive breast and gynaecological cancers. Those studies found that cancers fueled by the oestrogen hormone benefitted from derivatives of cholesterol that act like oestrogen, stoking cancer growth.
But a paradox emerged for estrogen-negative breast cancers. These cancers are not oestrogen dependent, but high cholesterol is still associated with worse disease, which indicates the possible effect of a different mechanism.
In the current study using cancer cell lines and mouse models, the Duke researchers found that migrating cancer cells gobble cholesterol in response to stress. Most die.
However, those that live emerge with a super-power that makes them able to withstand ferroptosis, a natural process in which cells succumb to stress. These stress-impervious cancer cells then proliferate and readily metastasise.
Other tumours beside ER-negative breast cancer cells use this process. including melanoma. And the mechanisms identified could be targeted by therapies.
“Unraveling this pathway has highlighted new approaches that may be useful for the treatment of advanced disease,” McDonnell said. “There are contemporary therapies under development that inhibit the pathway we’ve described. Importantly, these findings yet again highlight why lowering cholesterol — either using drugs or by dietary modification — is a good idea for better health.”
In a distinct on previous advice, new draft recommendations posted by the U.S. Preventive Services Task Force (USPSTF) advise against adults 60 and older to begin taking aspirin to lower their risk of a first heart attack or stroke.
They further advise that people aged 40 to 59 at higher risk for cardiovascular disease, but without a history of it, should talk to a health care provider before starting an aspirin regimen.
The proposed guidance is based on new evidence that suggests the potential harms of taking aspirin can outweigh the benefits. While daily aspirin use reduces the odds of a first heart attack or stroke, it increases the risks of gastrointestinal and intracerebral bleeding, which progressively increase with age.
“The latest evidence is clear: starting a daily aspirin regimen in people who are 60 or older to prevent a first heart attack or stroke is not recommended,” UPTSTF member Chien-Wen Tseng, MD, a professor at the University of Hawaii John A. Burns School of Medicine, said in a statement. “However, this Task Force recommendation is not for people already taking aspirin for a previous heart attack or stroke; they should continue to do so unless told otherwise by their clinician.”
The new guidance will be finalised after public comments close in November. It pivots from previous recommendations issued in 2016, which suggest that people ages 50 to 59 with a risk of cardiovascular disease ≥ 10% in the next decade and a low risk for bleeding take a daily low-dose aspirin (≤ 100mg/day) to reduce the likelihood of suffering a heart attack or stroke. According to the 2016 recommendations, the decision to start taking aspirin for preventive reasons should be “an individual one” for adults ages 60 to 69 who are at risk for cardiovascular disease
At present, neither the American Heart Association nor the American College of Cardiology recommend aspirin use for the prevention of heart attack and stroke in the general population; this only applies for some people between the ages of 40 and 70 who have never had a heart attack or stroke but have an increased risk for cardiovascular disease and a low risk for bleeding. The groups recommend that adults 70 and up should not take aspirin for first stroke or heart attack prevention.
Still, aspirin use for cardiovascular risk prevention is widespread in the US, “and is often self-initiated rather than recommended by a physician,” the latest USPSTF report states. A 2017 National Health Interview Survey (NHIS) found that 23.4 percent of adults age 40 or older and without cardiovascular disease took aspirin for primary prevention; among adults 60-69 years, 34.7 percent reported aspirin use. Tomas Ayala, MD, a cardiologist at Mercy Personal Physicians, said that this pivot had been anticipated by doctors.
“It is not that aspirin is less effective at reducing heart attacks or strokes than it once was,” he told Health. “Rather, it is that we have other therapies at our disposal that have reduced the overall population risk of these conditions, so the relative benefit of aspirin is less, and in many cases, is outweighed by the risks.”
SARS-CoV-2 virus. Source: Fusion Medical Animation on Unsplash
The global race to develop new stem cell-based COVID treatments during the pandemic was filled with violations of government regulations, inflated medical claims and distorted public communication, according to an article appearing in Stem Cell Reports.
While stem cell therapy has treatment applications for a limited range of diseases and conditions, at present no clinically tested or government-approved cell therapies are available for the treatment or prevention of COVID or long COVID.
Despite this, some clinics have started offering unproven and unsafe “stem cell” therapies that promise to prevent COVID by strengthening the immune system or improving overall health, according to lead author Laertis Ikonomou, PhD, associate professor of oral biology in the University at Buffalo School of Dental Medicine.
The article explores the negative effects that misinformation about cell therapies has on public health, as well as the roles that researchers, science communicators and regulatory agencies should play in curbing the spread of inaccurate information and in promoting responsible, accurate communication of research findings.
“Efforts to rapidly develop therapeutic interventions should never occur at the expense of the ethical and scientific standards that are at the heart of responsible clinical research and innovation,” said Prof Ikonomou.
Other investigators include Megan Munsie, PhD, professor of ethics, education and policy in stem cell science at the University of Melbourne; and
Many of the studies on possible stem cell-based COVID treatments are at an early stage of investigation and further evaluation on larger sample sizes is required, says Munsie. However, the findings from preliminary studies are frequently exaggerated through press releases, social media and uncritical news media reports.
“Given the urgency of the ongoing pandemic, even the smallest morsel of COVID science is often deemed newsworthy and rapidly enters a social media landscape where—regardless of its accuracy – it can be widely shared with a global audience,” said Aaron Levine, PhD, associate professor of public policy at Georgia Institute of Technology..
Clinics selling such treatments sometimes use these findings and news reports to exploit the fears of vulnerable patients by unethically advertising unproven stem cell treatments benefits of boosting the immune system, regenerating lung tissue and preventing transmission of COVID, said co-author Leigh Turner, PhD, professor of health, society and behaviour at the University of California, Irvine.
Reportedly some harm to patients resulted from unproven stem cell therapies, including blindness and death. Patients suffer financially as well, said Prof Ikonomou, as the products range in price from a few thousand to tens of thousands of dollars, and people are often encouraged to receive the expensive treatments every few months.
Patients who COVID may decline vaccines, stop wearing masks and stop other COVID safety measures, Prof Turner warned. They may also be less likely to participate in ethically conducted clinical trials.
“The premature commercialisation of cell-based therapeutics will inevitably harm the field of regenerative medicine, increase risks to patients and erode the public’s trust,” said Prof Ikonomou.
Despite warnings, many offending companies continue to make false claims. The authors recommend that regulatory agencies consider implementing stronger measures.
They also suggest that scientific and professional societies lobby regulatory agencies to increase enforcement of laws and regulations. The authors recommended that science communicators and journalists can combat misinformation by not engaging in hyperbolic coverage of research results and conveying study limitations.
