(Press-News.org) A study explains why cuff-based blood pressure readings systematically underestimate systolic blood pressure. High blood pressure is the most important risk factor for premature death. Yet the gold standard method for measuring blood pressure, the inflatable cuff, is known to systematically underestimate systolic (maximum) blood pressure and overestimate diastolic (minimum) blood pressure. To measure blood pressure, a cuff is placed around the upper arm and inflated to constrict the brachial artery, collapsing it. The pressure is then slowly released, until blood begins to flow through the artery again. With each blood pressure pulse, the blood pressure briefly exceeds the cuff pressure, and the artery opens, producing a tapping sound heard by the clinician. The cuff pressure continues to decrease, until the blood pressure exceeds the cuff pressure throughout the whole cardiac cycle. The artery is then fully open, and the tapping sounds disappear. The cuff pressures at which the tapping sounds appear and disappear are noted as the systolic and diastolic pressures, respectively. The reason for the overestimation of the minimum pressure is well understood: to fully occlude the artery, the cuff needs a little extra pressure to counteract the tissue around the artery and the stiffness of arterial walls. But the reason for the underestimation of systolic pressure has been unknown. Kate Bassil and Anurag Agarwal use a novel experimental rig that more accurately reproduces the behavior of the human circulatory system than previous rigs. The authors show that when the artery is closed, the blood pressure downstream of the cuff drops, as pressure equalizes in the isolated vasculature of the arm and hand. The cuff does not apply even pressure, and this, in combination with the low downstream pressure, changes the length of the closed section of artery under the cuff. The artery opens from the upstream side to the downstream side, but the detectable signal won’t be present until the whole length is open—and the longer it takes to open, the lower the pressure readings will have fallen before the clinician notes it. In sum, the lower the downstream pressure, the longer the section of artery that closes, the more time the artery takes to reopen, and the greater the underestimation of the systolic blood pressure. According to the authors, the study could inform improved calibration methods or refinements to the cuff protocol.
END
Better calibration for cuff-based blood pressure readings
2025-08-12
ELSE PRESS RELEASES FROM THIS DATE:
The future of ‘personalized’ cancer treatment: Antitumor mRNA-based vaccines
2025-08-12
Gastric cancer is one of the leading causes of cancer-related mortality worldwide, and peritoneal metastasis, wherein the cancer spreads to the peritoneum or the lining of the abdominal cavity, represents the most common form of recurrence after gastric cancer surgery. This form of metastasis is particularly associated with poor survival outcomes, as current first-line treatment options, including anti-PD-1 therapy combined with chemotherapy, have proven ineffective against peritoneal dissemination.
Immunotherapy presents an attractive option for tackling this challenging condition—more ...
Common food thickeners – long thought to pass right through us – are actually digested
2025-08-12
It turns out those cellulose-based thickening agents found in common foods can be digested.
Researchers at the University of British Columbia have shown that our gut bacteria can feed on these large molecules – something thought to not be possible – thanks to enzymes that normally help us break down dietary fibre.
“Researchers assumed that these thickening agents, which are artificial derivatives of natural cellulose, just pass right through the digestive system unaltered,” says Dr. Deepesh Panwar, a postdoctoral fellow ...
Off-the-shelf cancer vaccine elicits strong immune response in patients with pancreatic and colorectal cancer
2025-08-12
A novel cancer vaccine that stimulates the immune system to target one of the most common cancer-driving mutations has shown encouraging early results in patients with pancreatic and colorectal cancer, two of the most difficult-to-treat malignancies, according to a study led in part by investigators at the UCLA Health Jonsson Comprehensive Cancer Center.
The findings, published in Nature Medicine, show that the vaccine, called ELI-002 2P, can trigger powerful and lasting immune responses and may help prevent or delay cancer recurrence in high-risk patients whose tumors are driven by KRAS ...
New strategy to boost the effect of immunotherapy in the most aggressive form of lung cancer
2025-08-12
Adding a MET gene inhibitor enhances the effect of combined chemotherapy and immunotherapy in small cell lung cancer (SCLC), according to a multicenter study led by the Hospital del Mar Research Institute, in collaboration with researchers from the CIBERONC cancer research network. The study, published in Cell Reports Medicine, highlights the role of HGF (hepatocyte growth factor)—which is linked to cell proliferation and survival—in the poor prognosis of this disease and its resistance to treatment. The research explores a novel approach that adds a MET inhibitor to standard therapy and demonstrates improved treatment response.
Small cell lung cancer is one of the most aggressive ...
Counties with animal feeding operations have more air pollution, less health insurance coverage
2025-08-12
There are more than 15,000 cattle and hog feeding operations in the United States. These operations rear 70% of the country's cattle and 98% of its hogs.
Now, for the first time in the nation's history, we know with certainty where most of them are, thanks to research from the University of Michigan.
The research team found that a quarter of the nation's hog and cattle feeding operations are found in just 30 counties out of more than 3,000 in the United States. Going a step further, the team also found that an air pollutant linked to heart and respiratory issues near these animal feeding operations, ...
Mirror-like graphite films break records in strength and conductivity
2025-08-12
Graphite has attracted global interest due to its unique anisotropic properties, including excellent electrical and thermal conductivity. Widely used as a battery anode material and in applications such as electromagnetic shielding, catalysis, and nuclear technology, graphite remains a critical material in both industrial and research fields.
For decades, researchers have sought to produce high-quality artificial graphite with large grains and smooth, layered structures. Conventional methods typically involve high-temperature treatment of polymer ...
AI uncovers new antibiotics in ancient microbes
2025-08-12
They’ve survived for billions of years in boiling acid, deep-sea vents and salt flats. Now, some of Earth’s oldest life forms — microbes called Archaea — are offering a new weapon in the fight against one of today’s most urgent health threats: antibiotic resistance.
In a new study published in Nature Microbiology, researchers at the University of Pennsylvania used artificial intelligence to identify previously unknown compounds in Archaea that could fuel the development ...
AI meets CRISPR for precise gene editing
2025-08-12
A research team headed by the University of Zurich has developed a powerful new method to precisely edit DNA by combining cutting-edge genetic engineering with artificial intelligence. This technique opens the door to more accurate modeling of human diseases and lays the groundwork for next-generation gene therapies.
Precise and targeted DNA editing by small point mutations as well as the integration of whole genes via CRISPR/Cas technology has great potential for applications in biotechnology and gene therapy. However, it is very important that the so-called “gene scissors” do not cause any unintended ...
New method to synthesize carbohydrates could pave the way to biomedical advances
2025-08-12
New method to synthesize carbohydrates could pave the way to biomedical advances
(Santa Barbara, Calif.) — Carbohydrate is a familiar term. It’s the bagel you had for breakfast, the bread in your sandwich, the slice of cake you’re thinking about sneaking later today. But carbs aren’t only in baked goods, and they’re not just found in foods. Small yet structurally complex carbohydrates serve as elements of cell walls and are important in intercellular interactions.
Scientists can quickly and reliably make many biomolecules, from DNA to proteins, using automated instruments. So it may come as a surprise that for decades, scientists have had major difficulty ...
Plants feed through one-way routes
2025-08-12
Plants transport water and nutrients from their environment through specialised pores. Researchers at the University of Geneva (UNIGE) have shed light on a little-known but essential mechanism for proper plant function: the directionality of nutrient transport in roots. The team demonstrates that this transport becomes unidirectional as the root develops. This discovery highlights the central role of the pores connecting plant cells and opens up new perspectives for improving plant resistance to water stress. These findings are published in the journal Molecular Plant.
Roots play ...